Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/printk.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * Modified to make sys_syslog() more flexible: added commands to | |
7 | * return the last 4k of kernel messages, regardless of whether | |
8 | * they've been read or not. Added option to suppress kernel printk's | |
9 | * to the console. Added hook for sending the console messages | |
10 | * elsewhere, in preparation for a serial line console (someday). | |
11 | * Ted Ts'o, 2/11/93. | |
12 | * Modified for sysctl support, 1/8/97, Chris Horn. | |
40dc5651 | 13 | * Fixed SMP synchronization, 08/08/99, Manfred Spraul |
624dffcb | 14 | * manfred@colorfullife.com |
1da177e4 | 15 | * Rewrote bits to get rid of console_lock |
e1f8e874 | 16 | * 01Mar01 Andrew Morton |
1da177e4 LT |
17 | */ |
18 | ||
19 | #include <linux/kernel.h> | |
20 | #include <linux/mm.h> | |
21 | #include <linux/tty.h> | |
22 | #include <linux/tty_driver.h> | |
1da177e4 LT |
23 | #include <linux/console.h> |
24 | #include <linux/init.h> | |
bfe8df3d RD |
25 | #include <linux/jiffies.h> |
26 | #include <linux/nmi.h> | |
1da177e4 | 27 | #include <linux/module.h> |
3b9c0410 | 28 | #include <linux/moduleparam.h> |
1da177e4 | 29 | #include <linux/interrupt.h> /* For in_interrupt() */ |
1da177e4 LT |
30 | #include <linux/delay.h> |
31 | #include <linux/smp.h> | |
32 | #include <linux/security.h> | |
33 | #include <linux/bootmem.h> | |
162a7e75 | 34 | #include <linux/memblock.h> |
1da177e4 | 35 | #include <linux/syscalls.h> |
04d491ab | 36 | #include <linux/kexec.h> |
d37d39ae | 37 | #include <linux/kdb.h> |
3fff4c42 | 38 | #include <linux/ratelimit.h> |
456b565c | 39 | #include <linux/kmsg_dump.h> |
00234592 | 40 | #include <linux/syslog.h> |
034260d6 KC |
41 | #include <linux/cpu.h> |
42 | #include <linux/notifier.h> | |
fb842b00 | 43 | #include <linux/rculist.h> |
e11fea92 | 44 | #include <linux/poll.h> |
74876a98 | 45 | #include <linux/irq_work.h> |
196779b9 | 46 | #include <linux/utsname.h> |
249771b8 | 47 | #include <linux/ctype.h> |
e2e40f2c | 48 | #include <linux/uio.h> |
1da177e4 LT |
49 | |
50 | #include <asm/uaccess.h> | |
51 | ||
95100358 JB |
52 | #define CREATE_TRACE_POINTS |
53 | #include <trace/events/printk.h> | |
54 | ||
d197c43d | 55 | #include "console_cmdline.h" |
bbeddf52 | 56 | #include "braille.h" |
d197c43d | 57 | |
1da177e4 | 58 | int console_printk[4] = { |
a8fe19eb | 59 | CONSOLE_LOGLEVEL_DEFAULT, /* console_loglevel */ |
42a9dc0b | 60 | MESSAGE_LOGLEVEL_DEFAULT, /* default_message_loglevel */ |
a8fe19eb BP |
61 | CONSOLE_LOGLEVEL_MIN, /* minimum_console_loglevel */ |
62 | CONSOLE_LOGLEVEL_DEFAULT, /* default_console_loglevel */ | |
1da177e4 LT |
63 | }; |
64 | ||
1da177e4 | 65 | /* |
0bbfb7c2 | 66 | * Low level drivers may need that to know if they can schedule in |
1da177e4 LT |
67 | * their unblank() callback or not. So let's export it. |
68 | */ | |
69 | int oops_in_progress; | |
70 | EXPORT_SYMBOL(oops_in_progress); | |
71 | ||
72 | /* | |
73 | * console_sem protects the console_drivers list, and also | |
74 | * provides serialisation for access to the entire console | |
75 | * driver system. | |
76 | */ | |
5b8c4f23 | 77 | static DEFINE_SEMAPHORE(console_sem); |
1da177e4 | 78 | struct console *console_drivers; |
a29d1cfe IM |
79 | EXPORT_SYMBOL_GPL(console_drivers); |
80 | ||
daee7797 DV |
81 | #ifdef CONFIG_LOCKDEP |
82 | static struct lockdep_map console_lock_dep_map = { | |
83 | .name = "console_lock" | |
84 | }; | |
85 | #endif | |
86 | ||
bd8d7cf5 JK |
87 | /* |
88 | * Helper macros to handle lockdep when locking/unlocking console_sem. We use | |
89 | * macros instead of functions so that _RET_IP_ contains useful information. | |
90 | */ | |
91 | #define down_console_sem() do { \ | |
92 | down(&console_sem);\ | |
93 | mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);\ | |
94 | } while (0) | |
95 | ||
96 | static int __down_trylock_console_sem(unsigned long ip) | |
97 | { | |
98 | if (down_trylock(&console_sem)) | |
99 | return 1; | |
100 | mutex_acquire(&console_lock_dep_map, 0, 1, ip); | |
101 | return 0; | |
102 | } | |
103 | #define down_trylock_console_sem() __down_trylock_console_sem(_RET_IP_) | |
104 | ||
105 | #define up_console_sem() do { \ | |
106 | mutex_release(&console_lock_dep_map, 1, _RET_IP_);\ | |
107 | up(&console_sem);\ | |
108 | } while (0) | |
109 | ||
1da177e4 LT |
110 | /* |
111 | * This is used for debugging the mess that is the VT code by | |
112 | * keeping track if we have the console semaphore held. It's | |
113 | * definitely not the perfect debug tool (we don't know if _WE_ | |
0b90fec3 AE |
114 | * hold it and are racing, but it helps tracking those weird code |
115 | * paths in the console code where we end up in places I want | |
116 | * locked without the console sempahore held). | |
1da177e4 | 117 | */ |
557240b4 | 118 | static int console_locked, console_suspended; |
1da177e4 | 119 | |
fe3d8ad3 FT |
120 | /* |
121 | * If exclusive_console is non-NULL then only this console is to be printed to. | |
122 | */ | |
123 | static struct console *exclusive_console; | |
124 | ||
1da177e4 LT |
125 | /* |
126 | * Array of consoles built from command line options (console=) | |
127 | */ | |
1da177e4 LT |
128 | |
129 | #define MAX_CMDLINECONSOLES 8 | |
130 | ||
131 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; | |
d197c43d | 132 | |
1da177e4 LT |
133 | static int selected_console = -1; |
134 | static int preferred_console = -1; | |
9e124fe1 MA |
135 | int console_set_on_cmdline; |
136 | EXPORT_SYMBOL(console_set_on_cmdline); | |
1da177e4 LT |
137 | |
138 | /* Flag: console code may call schedule() */ | |
139 | static int console_may_schedule; | |
140 | ||
7ff9554b KS |
141 | /* |
142 | * The printk log buffer consists of a chain of concatenated variable | |
143 | * length records. Every record starts with a record header, containing | |
144 | * the overall length of the record. | |
145 | * | |
146 | * The heads to the first and last entry in the buffer, as well as the | |
0b90fec3 AE |
147 | * sequence numbers of these entries are maintained when messages are |
148 | * stored. | |
7ff9554b KS |
149 | * |
150 | * If the heads indicate available messages, the length in the header | |
151 | * tells the start next message. A length == 0 for the next message | |
152 | * indicates a wrap-around to the beginning of the buffer. | |
153 | * | |
154 | * Every record carries the monotonic timestamp in microseconds, as well as | |
155 | * the standard userspace syslog level and syslog facility. The usual | |
156 | * kernel messages use LOG_KERN; userspace-injected messages always carry | |
157 | * a matching syslog facility, by default LOG_USER. The origin of every | |
158 | * message can be reliably determined that way. | |
159 | * | |
160 | * The human readable log message directly follows the message header. The | |
161 | * length of the message text is stored in the header, the stored message | |
162 | * is not terminated. | |
163 | * | |
e11fea92 KS |
164 | * Optionally, a message can carry a dictionary of properties (key/value pairs), |
165 | * to provide userspace with a machine-readable message context. | |
166 | * | |
167 | * Examples for well-defined, commonly used property names are: | |
168 | * DEVICE=b12:8 device identifier | |
169 | * b12:8 block dev_t | |
170 | * c127:3 char dev_t | |
171 | * n8 netdev ifindex | |
172 | * +sound:card0 subsystem:devname | |
173 | * SUBSYSTEM=pci driver-core subsystem name | |
174 | * | |
175 | * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value | |
176 | * follows directly after a '=' character. Every property is terminated by | |
177 | * a '\0' character. The last property is not terminated. | |
178 | * | |
179 | * Example of a message structure: | |
180 | * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec | |
181 | * 0008 34 00 record is 52 bytes long | |
182 | * 000a 0b 00 text is 11 bytes long | |
183 | * 000c 1f 00 dictionary is 23 bytes long | |
184 | * 000e 03 00 LOG_KERN (facility) LOG_ERR (level) | |
185 | * 0010 69 74 27 73 20 61 20 6c "it's a l" | |
186 | * 69 6e 65 "ine" | |
187 | * 001b 44 45 56 49 43 "DEVIC" | |
188 | * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D" | |
189 | * 52 49 56 45 52 3d 62 75 "RIVER=bu" | |
190 | * 67 "g" | |
191 | * 0032 00 00 00 padding to next message header | |
192 | * | |
62e32ac3 | 193 | * The 'struct printk_log' buffer header must never be directly exported to |
e11fea92 KS |
194 | * userspace, it is a kernel-private implementation detail that might |
195 | * need to be changed in the future, when the requirements change. | |
196 | * | |
197 | * /dev/kmsg exports the structured data in the following line format: | |
198 | * "level,sequnum,timestamp;<message text>\n" | |
199 | * | |
200 | * The optional key/value pairs are attached as continuation lines starting | |
201 | * with a space character and terminated by a newline. All possible | |
202 | * non-prinatable characters are escaped in the "\xff" notation. | |
203 | * | |
204 | * Users of the export format should ignore possible additional values | |
205 | * separated by ',', and find the message after the ';' character. | |
7ff9554b KS |
206 | */ |
207 | ||
084681d1 | 208 | enum log_flags { |
5becfb1d KS |
209 | LOG_NOCONS = 1, /* already flushed, do not print to console */ |
210 | LOG_NEWLINE = 2, /* text ended with a newline */ | |
211 | LOG_PREFIX = 4, /* text started with a prefix */ | |
212 | LOG_CONT = 8, /* text is a fragment of a continuation line */ | |
084681d1 KS |
213 | }; |
214 | ||
62e32ac3 | 215 | struct printk_log { |
7ff9554b KS |
216 | u64 ts_nsec; /* timestamp in nanoseconds */ |
217 | u16 len; /* length of entire record */ | |
218 | u16 text_len; /* length of text buffer */ | |
219 | u16 dict_len; /* length of dictionary buffer */ | |
084681d1 KS |
220 | u8 facility; /* syslog facility */ |
221 | u8 flags:5; /* internal record flags */ | |
222 | u8 level:3; /* syslog level */ | |
7ff9554b KS |
223 | }; |
224 | ||
225 | /* | |
458df9fd SR |
226 | * The logbuf_lock protects kmsg buffer, indices, counters. This can be taken |
227 | * within the scheduler's rq lock. It must be released before calling | |
228 | * console_unlock() or anything else that might wake up a process. | |
7ff9554b KS |
229 | */ |
230 | static DEFINE_RAW_SPINLOCK(logbuf_lock); | |
d59745ce | 231 | |
96efedf1 | 232 | #ifdef CONFIG_PRINTK |
dc72c32e | 233 | DECLARE_WAIT_QUEUE_HEAD(log_wait); |
7f3a781d KS |
234 | /* the next printk record to read by syslog(READ) or /proc/kmsg */ |
235 | static u64 syslog_seq; | |
236 | static u32 syslog_idx; | |
5becfb1d | 237 | static enum log_flags syslog_prev; |
eb02dac9 | 238 | static size_t syslog_partial; |
7ff9554b KS |
239 | |
240 | /* index and sequence number of the first record stored in the buffer */ | |
241 | static u64 log_first_seq; | |
242 | static u32 log_first_idx; | |
243 | ||
244 | /* index and sequence number of the next record to store in the buffer */ | |
245 | static u64 log_next_seq; | |
246 | static u32 log_next_idx; | |
247 | ||
eab07260 KS |
248 | /* the next printk record to write to the console */ |
249 | static u64 console_seq; | |
250 | static u32 console_idx; | |
251 | static enum log_flags console_prev; | |
252 | ||
7ff9554b KS |
253 | /* the next printk record to read after the last 'clear' command */ |
254 | static u64 clear_seq; | |
255 | static u32 clear_idx; | |
256 | ||
70498253 | 257 | #define PREFIX_MAX 32 |
249771b8 | 258 | #define LOG_LINE_MAX (1024 - PREFIX_MAX) |
7f3a781d KS |
259 | |
260 | /* record buffer */ | |
6ebb017d | 261 | #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) |
f8450fca SW |
262 | #define LOG_ALIGN 4 |
263 | #else | |
62e32ac3 | 264 | #define LOG_ALIGN __alignof__(struct printk_log) |
f8450fca | 265 | #endif |
7f3a781d | 266 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
f8450fca | 267 | static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); |
7f3a781d KS |
268 | static char *log_buf = __log_buf; |
269 | static u32 log_buf_len = __LOG_BUF_LEN; | |
270 | ||
14c4000a VH |
271 | /* Return log buffer address */ |
272 | char *log_buf_addr_get(void) | |
273 | { | |
274 | return log_buf; | |
275 | } | |
276 | ||
277 | /* Return log buffer size */ | |
278 | u32 log_buf_len_get(void) | |
279 | { | |
280 | return log_buf_len; | |
281 | } | |
282 | ||
7ff9554b | 283 | /* human readable text of the record */ |
62e32ac3 | 284 | static char *log_text(const struct printk_log *msg) |
7ff9554b | 285 | { |
62e32ac3 | 286 | return (char *)msg + sizeof(struct printk_log); |
7ff9554b KS |
287 | } |
288 | ||
289 | /* optional key/value pair dictionary attached to the record */ | |
62e32ac3 | 290 | static char *log_dict(const struct printk_log *msg) |
7ff9554b | 291 | { |
62e32ac3 | 292 | return (char *)msg + sizeof(struct printk_log) + msg->text_len; |
7ff9554b KS |
293 | } |
294 | ||
295 | /* get record by index; idx must point to valid msg */ | |
62e32ac3 | 296 | static struct printk_log *log_from_idx(u32 idx) |
7ff9554b | 297 | { |
62e32ac3 | 298 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
299 | |
300 | /* | |
301 | * A length == 0 record is the end of buffer marker. Wrap around and | |
302 | * read the message at the start of the buffer. | |
303 | */ | |
304 | if (!msg->len) | |
62e32ac3 | 305 | return (struct printk_log *)log_buf; |
7ff9554b KS |
306 | return msg; |
307 | } | |
308 | ||
309 | /* get next record; idx must point to valid msg */ | |
310 | static u32 log_next(u32 idx) | |
311 | { | |
62e32ac3 | 312 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
313 | |
314 | /* length == 0 indicates the end of the buffer; wrap */ | |
315 | /* | |
316 | * A length == 0 record is the end of buffer marker. Wrap around and | |
317 | * read the message at the start of the buffer as *this* one, and | |
318 | * return the one after that. | |
319 | */ | |
320 | if (!msg->len) { | |
62e32ac3 | 321 | msg = (struct printk_log *)log_buf; |
7ff9554b KS |
322 | return msg->len; |
323 | } | |
324 | return idx + msg->len; | |
325 | } | |
326 | ||
f40e4b9f PM |
327 | /* |
328 | * Check whether there is enough free space for the given message. | |
329 | * | |
330 | * The same values of first_idx and next_idx mean that the buffer | |
331 | * is either empty or full. | |
332 | * | |
333 | * If the buffer is empty, we must respect the position of the indexes. | |
334 | * They cannot be reset to the beginning of the buffer. | |
335 | */ | |
336 | static int logbuf_has_space(u32 msg_size, bool empty) | |
0a581694 PM |
337 | { |
338 | u32 free; | |
339 | ||
f40e4b9f | 340 | if (log_next_idx > log_first_idx || empty) |
0a581694 PM |
341 | free = max(log_buf_len - log_next_idx, log_first_idx); |
342 | else | |
343 | free = log_first_idx - log_next_idx; | |
344 | ||
345 | /* | |
346 | * We need space also for an empty header that signalizes wrapping | |
347 | * of the buffer. | |
348 | */ | |
349 | return free >= msg_size + sizeof(struct printk_log); | |
350 | } | |
351 | ||
f40e4b9f | 352 | static int log_make_free_space(u32 msg_size) |
0a581694 PM |
353 | { |
354 | while (log_first_seq < log_next_seq) { | |
f40e4b9f PM |
355 | if (logbuf_has_space(msg_size, false)) |
356 | return 0; | |
0b90fec3 | 357 | /* drop old messages until we have enough contiguous space */ |
0a581694 PM |
358 | log_first_idx = log_next(log_first_idx); |
359 | log_first_seq++; | |
360 | } | |
f40e4b9f PM |
361 | |
362 | /* sequence numbers are equal, so the log buffer is empty */ | |
363 | if (logbuf_has_space(msg_size, true)) | |
364 | return 0; | |
365 | ||
366 | return -ENOMEM; | |
0a581694 PM |
367 | } |
368 | ||
85c87043 PM |
369 | /* compute the message size including the padding bytes */ |
370 | static u32 msg_used_size(u16 text_len, u16 dict_len, u32 *pad_len) | |
371 | { | |
372 | u32 size; | |
373 | ||
374 | size = sizeof(struct printk_log) + text_len + dict_len; | |
375 | *pad_len = (-size) & (LOG_ALIGN - 1); | |
376 | size += *pad_len; | |
377 | ||
378 | return size; | |
379 | } | |
380 | ||
55bd53a4 PM |
381 | /* |
382 | * Define how much of the log buffer we could take at maximum. The value | |
383 | * must be greater than two. Note that only half of the buffer is available | |
384 | * when the index points to the middle. | |
385 | */ | |
386 | #define MAX_LOG_TAKE_PART 4 | |
387 | static const char trunc_msg[] = "<truncated>"; | |
388 | ||
389 | static u32 truncate_msg(u16 *text_len, u16 *trunc_msg_len, | |
390 | u16 *dict_len, u32 *pad_len) | |
391 | { | |
392 | /* | |
393 | * The message should not take the whole buffer. Otherwise, it might | |
394 | * get removed too soon. | |
395 | */ | |
396 | u32 max_text_len = log_buf_len / MAX_LOG_TAKE_PART; | |
397 | if (*text_len > max_text_len) | |
398 | *text_len = max_text_len; | |
399 | /* enable the warning message */ | |
400 | *trunc_msg_len = strlen(trunc_msg); | |
401 | /* disable the "dict" completely */ | |
402 | *dict_len = 0; | |
403 | /* compute the size again, count also the warning message */ | |
404 | return msg_used_size(*text_len + *trunc_msg_len, 0, pad_len); | |
405 | } | |
406 | ||
7ff9554b | 407 | /* insert record into the buffer, discard old ones, update heads */ |
034633cc PM |
408 | static int log_store(int facility, int level, |
409 | enum log_flags flags, u64 ts_nsec, | |
410 | const char *dict, u16 dict_len, | |
411 | const char *text, u16 text_len) | |
7ff9554b | 412 | { |
62e32ac3 | 413 | struct printk_log *msg; |
7ff9554b | 414 | u32 size, pad_len; |
55bd53a4 | 415 | u16 trunc_msg_len = 0; |
7ff9554b KS |
416 | |
417 | /* number of '\0' padding bytes to next message */ | |
85c87043 | 418 | size = msg_used_size(text_len, dict_len, &pad_len); |
7ff9554b | 419 | |
55bd53a4 PM |
420 | if (log_make_free_space(size)) { |
421 | /* truncate the message if it is too long for empty buffer */ | |
422 | size = truncate_msg(&text_len, &trunc_msg_len, | |
423 | &dict_len, &pad_len); | |
424 | /* survive when the log buffer is too small for trunc_msg */ | |
425 | if (log_make_free_space(size)) | |
034633cc | 426 | return 0; |
55bd53a4 | 427 | } |
7ff9554b | 428 | |
39b25109 | 429 | if (log_next_idx + size + sizeof(struct printk_log) > log_buf_len) { |
7ff9554b KS |
430 | /* |
431 | * This message + an additional empty header does not fit | |
432 | * at the end of the buffer. Add an empty header with len == 0 | |
433 | * to signify a wrap around. | |
434 | */ | |
62e32ac3 | 435 | memset(log_buf + log_next_idx, 0, sizeof(struct printk_log)); |
7ff9554b KS |
436 | log_next_idx = 0; |
437 | } | |
438 | ||
439 | /* fill message */ | |
62e32ac3 | 440 | msg = (struct printk_log *)(log_buf + log_next_idx); |
7ff9554b KS |
441 | memcpy(log_text(msg), text, text_len); |
442 | msg->text_len = text_len; | |
55bd53a4 PM |
443 | if (trunc_msg_len) { |
444 | memcpy(log_text(msg) + text_len, trunc_msg, trunc_msg_len); | |
445 | msg->text_len += trunc_msg_len; | |
446 | } | |
7ff9554b KS |
447 | memcpy(log_dict(msg), dict, dict_len); |
448 | msg->dict_len = dict_len; | |
084681d1 KS |
449 | msg->facility = facility; |
450 | msg->level = level & 7; | |
451 | msg->flags = flags & 0x1f; | |
452 | if (ts_nsec > 0) | |
453 | msg->ts_nsec = ts_nsec; | |
454 | else | |
455 | msg->ts_nsec = local_clock(); | |
7ff9554b | 456 | memset(log_dict(msg) + dict_len, 0, pad_len); |
fce6e033 | 457 | msg->len = size; |
7ff9554b KS |
458 | |
459 | /* insert message */ | |
460 | log_next_idx += msg->len; | |
461 | log_next_seq++; | |
034633cc PM |
462 | |
463 | return msg->text_len; | |
7ff9554b | 464 | } |
d59745ce | 465 | |
e99aa461 | 466 | int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT); |
637241a9 KC |
467 | |
468 | static int syslog_action_restricted(int type) | |
469 | { | |
470 | if (dmesg_restrict) | |
471 | return 1; | |
472 | /* | |
473 | * Unless restricted, we allow "read all" and "get buffer size" | |
474 | * for everybody. | |
475 | */ | |
476 | return type != SYSLOG_ACTION_READ_ALL && | |
477 | type != SYSLOG_ACTION_SIZE_BUFFER; | |
478 | } | |
479 | ||
68c4a4f8 | 480 | int check_syslog_permissions(int type, bool from_file) |
637241a9 KC |
481 | { |
482 | /* | |
483 | * If this is from /proc/kmsg and we've already opened it, then we've | |
484 | * already done the capabilities checks at open time. | |
485 | */ | |
486 | if (from_file && type != SYSLOG_ACTION_OPEN) | |
487 | return 0; | |
488 | ||
489 | if (syslog_action_restricted(type)) { | |
490 | if (capable(CAP_SYSLOG)) | |
491 | return 0; | |
492 | /* | |
493 | * For historical reasons, accept CAP_SYS_ADMIN too, with | |
494 | * a warning. | |
495 | */ | |
496 | if (capable(CAP_SYS_ADMIN)) { | |
497 | pr_warn_once("%s (%d): Attempt to access syslog with " | |
498 | "CAP_SYS_ADMIN but no CAP_SYSLOG " | |
499 | "(deprecated).\n", | |
500 | current->comm, task_pid_nr(current)); | |
501 | return 0; | |
502 | } | |
503 | return -EPERM; | |
504 | } | |
505 | return security_syslog(type); | |
506 | } | |
507 | ||
d43ff430 TH |
508 | static void append_char(char **pp, char *e, char c) |
509 | { | |
510 | if (*pp < e) | |
511 | *(*pp)++ = c; | |
512 | } | |
637241a9 | 513 | |
0a295e67 TH |
514 | static ssize_t msg_print_ext_header(char *buf, size_t size, |
515 | struct printk_log *msg, u64 seq, | |
516 | enum log_flags prev_flags) | |
517 | { | |
518 | u64 ts_usec = msg->ts_nsec; | |
519 | char cont = '-'; | |
520 | ||
521 | do_div(ts_usec, 1000); | |
522 | ||
523 | /* | |
524 | * If we couldn't merge continuation line fragments during the print, | |
525 | * export the stored flags to allow an optional external merge of the | |
526 | * records. Merging the records isn't always neccessarily correct, like | |
527 | * when we hit a race during printing. In most cases though, it produces | |
528 | * better readable output. 'c' in the record flags mark the first | |
529 | * fragment of a line, '+' the following. | |
530 | */ | |
531 | if (msg->flags & LOG_CONT && !(prev_flags & LOG_CONT)) | |
532 | cont = 'c'; | |
533 | else if ((msg->flags & LOG_CONT) || | |
534 | ((prev_flags & LOG_CONT) && !(msg->flags & LOG_PREFIX))) | |
535 | cont = '+'; | |
536 | ||
537 | return scnprintf(buf, size, "%u,%llu,%llu,%c;", | |
538 | (msg->facility << 3) | msg->level, seq, ts_usec, cont); | |
539 | } | |
540 | ||
541 | static ssize_t msg_print_ext_body(char *buf, size_t size, | |
542 | char *dict, size_t dict_len, | |
543 | char *text, size_t text_len) | |
544 | { | |
545 | char *p = buf, *e = buf + size; | |
546 | size_t i; | |
547 | ||
548 | /* escape non-printable characters */ | |
549 | for (i = 0; i < text_len; i++) { | |
550 | unsigned char c = text[i]; | |
551 | ||
552 | if (c < ' ' || c >= 127 || c == '\\') | |
553 | p += scnprintf(p, e - p, "\\x%02x", c); | |
554 | else | |
555 | append_char(&p, e, c); | |
556 | } | |
557 | append_char(&p, e, '\n'); | |
558 | ||
559 | if (dict_len) { | |
560 | bool line = true; | |
561 | ||
562 | for (i = 0; i < dict_len; i++) { | |
563 | unsigned char c = dict[i]; | |
564 | ||
565 | if (line) { | |
566 | append_char(&p, e, ' '); | |
567 | line = false; | |
568 | } | |
569 | ||
570 | if (c == '\0') { | |
571 | append_char(&p, e, '\n'); | |
572 | line = true; | |
573 | continue; | |
574 | } | |
575 | ||
576 | if (c < ' ' || c >= 127 || c == '\\') { | |
577 | p += scnprintf(p, e - p, "\\x%02x", c); | |
578 | continue; | |
579 | } | |
580 | ||
581 | append_char(&p, e, c); | |
582 | } | |
583 | append_char(&p, e, '\n'); | |
584 | } | |
585 | ||
586 | return p - buf; | |
587 | } | |
588 | ||
e11fea92 KS |
589 | /* /dev/kmsg - userspace message inject/listen interface */ |
590 | struct devkmsg_user { | |
591 | u64 seq; | |
592 | u32 idx; | |
d39f3d77 | 593 | enum log_flags prev; |
e11fea92 | 594 | struct mutex lock; |
d43ff430 | 595 | char buf[CONSOLE_EXT_LOG_MAX]; |
e11fea92 KS |
596 | }; |
597 | ||
849f3127 | 598 | static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from) |
e11fea92 KS |
599 | { |
600 | char *buf, *line; | |
601 | int i; | |
602 | int level = default_message_loglevel; | |
603 | int facility = 1; /* LOG_USER */ | |
66ee59af | 604 | size_t len = iov_iter_count(from); |
e11fea92 KS |
605 | ssize_t ret = len; |
606 | ||
607 | if (len > LOG_LINE_MAX) | |
608 | return -EINVAL; | |
609 | buf = kmalloc(len+1, GFP_KERNEL); | |
610 | if (buf == NULL) | |
611 | return -ENOMEM; | |
612 | ||
849f3127 AV |
613 | buf[len] = '\0'; |
614 | if (copy_from_iter(buf, len, from) != len) { | |
615 | kfree(buf); | |
616 | return -EFAULT; | |
e11fea92 KS |
617 | } |
618 | ||
619 | /* | |
620 | * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace | |
621 | * the decimal value represents 32bit, the lower 3 bit are the log | |
622 | * level, the rest are the log facility. | |
623 | * | |
624 | * If no prefix or no userspace facility is specified, we | |
625 | * enforce LOG_USER, to be able to reliably distinguish | |
626 | * kernel-generated messages from userspace-injected ones. | |
627 | */ | |
628 | line = buf; | |
629 | if (line[0] == '<') { | |
630 | char *endp = NULL; | |
631 | ||
632 | i = simple_strtoul(line+1, &endp, 10); | |
633 | if (endp && endp[0] == '>') { | |
634 | level = i & 7; | |
635 | if (i >> 3) | |
636 | facility = i >> 3; | |
637 | endp++; | |
638 | len -= endp - line; | |
639 | line = endp; | |
640 | } | |
641 | } | |
e11fea92 KS |
642 | |
643 | printk_emit(facility, level, NULL, 0, "%s", line); | |
e11fea92 KS |
644 | kfree(buf); |
645 | return ret; | |
646 | } | |
647 | ||
648 | static ssize_t devkmsg_read(struct file *file, char __user *buf, | |
649 | size_t count, loff_t *ppos) | |
650 | { | |
651 | struct devkmsg_user *user = file->private_data; | |
62e32ac3 | 652 | struct printk_log *msg; |
e11fea92 KS |
653 | size_t len; |
654 | ssize_t ret; | |
655 | ||
656 | if (!user) | |
657 | return -EBADF; | |
658 | ||
4a77a5a0 YL |
659 | ret = mutex_lock_interruptible(&user->lock); |
660 | if (ret) | |
661 | return ret; | |
5c53d819 | 662 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
663 | while (user->seq == log_next_seq) { |
664 | if (file->f_flags & O_NONBLOCK) { | |
665 | ret = -EAGAIN; | |
5c53d819 | 666 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
667 | goto out; |
668 | } | |
669 | ||
5c53d819 | 670 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
671 | ret = wait_event_interruptible(log_wait, |
672 | user->seq != log_next_seq); | |
673 | if (ret) | |
674 | goto out; | |
5c53d819 | 675 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
676 | } |
677 | ||
678 | if (user->seq < log_first_seq) { | |
679 | /* our last seen message is gone, return error and reset */ | |
680 | user->idx = log_first_idx; | |
681 | user->seq = log_first_seq; | |
682 | ret = -EPIPE; | |
5c53d819 | 683 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
684 | goto out; |
685 | } | |
686 | ||
687 | msg = log_from_idx(user->idx); | |
0a295e67 TH |
688 | len = msg_print_ext_header(user->buf, sizeof(user->buf), |
689 | msg, user->seq, user->prev); | |
690 | len += msg_print_ext_body(user->buf + len, sizeof(user->buf) - len, | |
691 | log_dict(msg), msg->dict_len, | |
692 | log_text(msg), msg->text_len); | |
d39f3d77 | 693 | |
d39f3d77 | 694 | user->prev = msg->flags; |
e11fea92 KS |
695 | user->idx = log_next(user->idx); |
696 | user->seq++; | |
5c53d819 | 697 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
698 | |
699 | if (len > count) { | |
700 | ret = -EINVAL; | |
701 | goto out; | |
702 | } | |
703 | ||
704 | if (copy_to_user(buf, user->buf, len)) { | |
705 | ret = -EFAULT; | |
706 | goto out; | |
707 | } | |
708 | ret = len; | |
709 | out: | |
710 | mutex_unlock(&user->lock); | |
711 | return ret; | |
712 | } | |
713 | ||
714 | static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) | |
715 | { | |
716 | struct devkmsg_user *user = file->private_data; | |
717 | loff_t ret = 0; | |
718 | ||
719 | if (!user) | |
720 | return -EBADF; | |
721 | if (offset) | |
722 | return -ESPIPE; | |
723 | ||
5c53d819 | 724 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
725 | switch (whence) { |
726 | case SEEK_SET: | |
727 | /* the first record */ | |
728 | user->idx = log_first_idx; | |
729 | user->seq = log_first_seq; | |
730 | break; | |
731 | case SEEK_DATA: | |
732 | /* | |
733 | * The first record after the last SYSLOG_ACTION_CLEAR, | |
734 | * like issued by 'dmesg -c'. Reading /dev/kmsg itself | |
735 | * changes no global state, and does not clear anything. | |
736 | */ | |
737 | user->idx = clear_idx; | |
738 | user->seq = clear_seq; | |
739 | break; | |
740 | case SEEK_END: | |
741 | /* after the last record */ | |
742 | user->idx = log_next_idx; | |
743 | user->seq = log_next_seq; | |
744 | break; | |
745 | default: | |
746 | ret = -EINVAL; | |
747 | } | |
5c53d819 | 748 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
749 | return ret; |
750 | } | |
751 | ||
752 | static unsigned int devkmsg_poll(struct file *file, poll_table *wait) | |
753 | { | |
754 | struct devkmsg_user *user = file->private_data; | |
755 | int ret = 0; | |
756 | ||
757 | if (!user) | |
758 | return POLLERR|POLLNVAL; | |
759 | ||
760 | poll_wait(file, &log_wait, wait); | |
761 | ||
5c53d819 | 762 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
763 | if (user->seq < log_next_seq) { |
764 | /* return error when data has vanished underneath us */ | |
765 | if (user->seq < log_first_seq) | |
766 | ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI; | |
0a285317 NK |
767 | else |
768 | ret = POLLIN|POLLRDNORM; | |
e11fea92 | 769 | } |
5c53d819 | 770 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
771 | |
772 | return ret; | |
773 | } | |
774 | ||
775 | static int devkmsg_open(struct inode *inode, struct file *file) | |
776 | { | |
777 | struct devkmsg_user *user; | |
778 | int err; | |
779 | ||
780 | /* write-only does not need any file context */ | |
781 | if ((file->f_flags & O_ACCMODE) == O_WRONLY) | |
782 | return 0; | |
783 | ||
637241a9 KC |
784 | err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL, |
785 | SYSLOG_FROM_READER); | |
e11fea92 KS |
786 | if (err) |
787 | return err; | |
788 | ||
789 | user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL); | |
790 | if (!user) | |
791 | return -ENOMEM; | |
792 | ||
793 | mutex_init(&user->lock); | |
794 | ||
5c53d819 | 795 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
796 | user->idx = log_first_idx; |
797 | user->seq = log_first_seq; | |
5c53d819 | 798 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
799 | |
800 | file->private_data = user; | |
801 | return 0; | |
802 | } | |
803 | ||
804 | static int devkmsg_release(struct inode *inode, struct file *file) | |
805 | { | |
806 | struct devkmsg_user *user = file->private_data; | |
807 | ||
808 | if (!user) | |
809 | return 0; | |
810 | ||
811 | mutex_destroy(&user->lock); | |
812 | kfree(user); | |
813 | return 0; | |
814 | } | |
815 | ||
816 | const struct file_operations kmsg_fops = { | |
817 | .open = devkmsg_open, | |
818 | .read = devkmsg_read, | |
849f3127 | 819 | .write_iter = devkmsg_write, |
e11fea92 KS |
820 | .llseek = devkmsg_llseek, |
821 | .poll = devkmsg_poll, | |
822 | .release = devkmsg_release, | |
823 | }; | |
824 | ||
04d491ab NH |
825 | #ifdef CONFIG_KEXEC |
826 | /* | |
4c1ace64 | 827 | * This appends the listed symbols to /proc/vmcore |
04d491ab | 828 | * |
4c1ace64 | 829 | * /proc/vmcore is used by various utilities, like crash and makedumpfile to |
04d491ab NH |
830 | * obtain access to symbols that are otherwise very difficult to locate. These |
831 | * symbols are specifically used so that utilities can access and extract the | |
832 | * dmesg log from a vmcore file after a crash. | |
833 | */ | |
834 | void log_buf_kexec_setup(void) | |
835 | { | |
836 | VMCOREINFO_SYMBOL(log_buf); | |
04d491ab | 837 | VMCOREINFO_SYMBOL(log_buf_len); |
7ff9554b KS |
838 | VMCOREINFO_SYMBOL(log_first_idx); |
839 | VMCOREINFO_SYMBOL(log_next_idx); | |
6791457a | 840 | /* |
62e32ac3 | 841 | * Export struct printk_log size and field offsets. User space tools can |
6791457a VG |
842 | * parse it and detect any changes to structure down the line. |
843 | */ | |
62e32ac3 JP |
844 | VMCOREINFO_STRUCT_SIZE(printk_log); |
845 | VMCOREINFO_OFFSET(printk_log, ts_nsec); | |
846 | VMCOREINFO_OFFSET(printk_log, len); | |
847 | VMCOREINFO_OFFSET(printk_log, text_len); | |
848 | VMCOREINFO_OFFSET(printk_log, dict_len); | |
04d491ab NH |
849 | } |
850 | #endif | |
851 | ||
162a7e75 MT |
852 | /* requested log_buf_len from kernel cmdline */ |
853 | static unsigned long __initdata new_log_buf_len; | |
854 | ||
c0a318a3 LR |
855 | /* we practice scaling the ring buffer by powers of 2 */ |
856 | static void __init log_buf_len_update(unsigned size) | |
1da177e4 | 857 | { |
1da177e4 LT |
858 | if (size) |
859 | size = roundup_pow_of_two(size); | |
162a7e75 MT |
860 | if (size > log_buf_len) |
861 | new_log_buf_len = size; | |
c0a318a3 LR |
862 | } |
863 | ||
864 | /* save requested log_buf_len since it's too early to process it */ | |
865 | static int __init log_buf_len_setup(char *str) | |
866 | { | |
867 | unsigned size = memparse(str, &str); | |
868 | ||
869 | log_buf_len_update(size); | |
162a7e75 MT |
870 | |
871 | return 0; | |
1da177e4 | 872 | } |
162a7e75 MT |
873 | early_param("log_buf_len", log_buf_len_setup); |
874 | ||
2240a31d GU |
875 | #ifdef CONFIG_SMP |
876 | #define __LOG_CPU_MAX_BUF_LEN (1 << CONFIG_LOG_CPU_MAX_BUF_SHIFT) | |
877 | ||
23b2899f LR |
878 | static void __init log_buf_add_cpu(void) |
879 | { | |
880 | unsigned int cpu_extra; | |
881 | ||
882 | /* | |
883 | * archs should set up cpu_possible_bits properly with | |
884 | * set_cpu_possible() after setup_arch() but just in | |
885 | * case lets ensure this is valid. | |
886 | */ | |
887 | if (num_possible_cpus() == 1) | |
888 | return; | |
889 | ||
890 | cpu_extra = (num_possible_cpus() - 1) * __LOG_CPU_MAX_BUF_LEN; | |
891 | ||
892 | /* by default this will only continue through for large > 64 CPUs */ | |
893 | if (cpu_extra <= __LOG_BUF_LEN / 2) | |
894 | return; | |
895 | ||
896 | pr_info("log_buf_len individual max cpu contribution: %d bytes\n", | |
897 | __LOG_CPU_MAX_BUF_LEN); | |
898 | pr_info("log_buf_len total cpu_extra contributions: %d bytes\n", | |
899 | cpu_extra); | |
900 | pr_info("log_buf_len min size: %d bytes\n", __LOG_BUF_LEN); | |
901 | ||
902 | log_buf_len_update(cpu_extra + __LOG_BUF_LEN); | |
903 | } | |
2240a31d GU |
904 | #else /* !CONFIG_SMP */ |
905 | static inline void log_buf_add_cpu(void) {} | |
906 | #endif /* CONFIG_SMP */ | |
23b2899f | 907 | |
162a7e75 MT |
908 | void __init setup_log_buf(int early) |
909 | { | |
910 | unsigned long flags; | |
162a7e75 MT |
911 | char *new_log_buf; |
912 | int free; | |
913 | ||
23b2899f LR |
914 | if (log_buf != __log_buf) |
915 | return; | |
916 | ||
917 | if (!early && !new_log_buf_len) | |
918 | log_buf_add_cpu(); | |
919 | ||
162a7e75 MT |
920 | if (!new_log_buf_len) |
921 | return; | |
1da177e4 | 922 | |
162a7e75 | 923 | if (early) { |
9da791df | 924 | new_log_buf = |
70300177 | 925 | memblock_virt_alloc(new_log_buf_len, LOG_ALIGN); |
162a7e75 | 926 | } else { |
70300177 LR |
927 | new_log_buf = memblock_virt_alloc_nopanic(new_log_buf_len, |
928 | LOG_ALIGN); | |
162a7e75 MT |
929 | } |
930 | ||
931 | if (unlikely(!new_log_buf)) { | |
932 | pr_err("log_buf_len: %ld bytes not available\n", | |
933 | new_log_buf_len); | |
934 | return; | |
935 | } | |
936 | ||
07354eb1 | 937 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
162a7e75 MT |
938 | log_buf_len = new_log_buf_len; |
939 | log_buf = new_log_buf; | |
940 | new_log_buf_len = 0; | |
7ff9554b KS |
941 | free = __LOG_BUF_LEN - log_next_idx; |
942 | memcpy(log_buf, __log_buf, __LOG_BUF_LEN); | |
07354eb1 | 943 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
162a7e75 | 944 | |
f5405172 | 945 | pr_info("log_buf_len: %d bytes\n", log_buf_len); |
162a7e75 MT |
946 | pr_info("early log buf free: %d(%d%%)\n", |
947 | free, (free * 100) / __LOG_BUF_LEN); | |
948 | } | |
1da177e4 | 949 | |
2fa72c8f AC |
950 | static bool __read_mostly ignore_loglevel; |
951 | ||
952 | static int __init ignore_loglevel_setup(char *str) | |
953 | { | |
d25d9fec | 954 | ignore_loglevel = true; |
27083bac | 955 | pr_info("debug: ignoring loglevel setting.\n"); |
2fa72c8f AC |
956 | |
957 | return 0; | |
958 | } | |
959 | ||
960 | early_param("ignore_loglevel", ignore_loglevel_setup); | |
961 | module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); | |
205bd3d2 JP |
962 | MODULE_PARM_DESC(ignore_loglevel, |
963 | "ignore loglevel setting (prints all kernel messages to the console)"); | |
2fa72c8f | 964 | |
bfe8df3d RD |
965 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
966 | ||
674dff65 | 967 | static int boot_delay; /* msecs delay after each printk during bootup */ |
3a3b6ed2 | 968 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
bfe8df3d RD |
969 | |
970 | static int __init boot_delay_setup(char *str) | |
971 | { | |
972 | unsigned long lpj; | |
bfe8df3d RD |
973 | |
974 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ | |
975 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; | |
976 | ||
977 | get_option(&str, &boot_delay); | |
978 | if (boot_delay > 10 * 1000) | |
979 | boot_delay = 0; | |
980 | ||
3a3b6ed2 DY |
981 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
982 | "HZ: %d, loops_per_msec: %llu\n", | |
983 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); | |
29e9d225 | 984 | return 0; |
bfe8df3d | 985 | } |
29e9d225 | 986 | early_param("boot_delay", boot_delay_setup); |
bfe8df3d | 987 | |
2fa72c8f | 988 | static void boot_delay_msec(int level) |
bfe8df3d RD |
989 | { |
990 | unsigned long long k; | |
991 | unsigned long timeout; | |
992 | ||
2fa72c8f AC |
993 | if ((boot_delay == 0 || system_state != SYSTEM_BOOTING) |
994 | || (level >= console_loglevel && !ignore_loglevel)) { | |
bfe8df3d | 995 | return; |
2fa72c8f | 996 | } |
bfe8df3d | 997 | |
3a3b6ed2 | 998 | k = (unsigned long long)loops_per_msec * boot_delay; |
bfe8df3d RD |
999 | |
1000 | timeout = jiffies + msecs_to_jiffies(boot_delay); | |
1001 | while (k) { | |
1002 | k--; | |
1003 | cpu_relax(); | |
1004 | /* | |
1005 | * use (volatile) jiffies to prevent | |
1006 | * compiler reduction; loop termination via jiffies | |
1007 | * is secondary and may or may not happen. | |
1008 | */ | |
1009 | if (time_after(jiffies, timeout)) | |
1010 | break; | |
1011 | touch_nmi_watchdog(); | |
1012 | } | |
1013 | } | |
1014 | #else | |
2fa72c8f | 1015 | static inline void boot_delay_msec(int level) |
bfe8df3d RD |
1016 | { |
1017 | } | |
1018 | #endif | |
1019 | ||
e99aa461 | 1020 | static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME); |
7ff9554b KS |
1021 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); |
1022 | ||
084681d1 KS |
1023 | static size_t print_time(u64 ts, char *buf) |
1024 | { | |
1025 | unsigned long rem_nsec; | |
1026 | ||
1027 | if (!printk_time) | |
1028 | return 0; | |
1029 | ||
35dac27c RD |
1030 | rem_nsec = do_div(ts, 1000000000); |
1031 | ||
084681d1 | 1032 | if (!buf) |
35dac27c | 1033 | return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts); |
084681d1 | 1034 | |
084681d1 KS |
1035 | return sprintf(buf, "[%5lu.%06lu] ", |
1036 | (unsigned long)ts, rem_nsec / 1000); | |
1037 | } | |
1038 | ||
62e32ac3 | 1039 | static size_t print_prefix(const struct printk_log *msg, bool syslog, char *buf) |
649e6ee3 | 1040 | { |
3ce9a7c0 | 1041 | size_t len = 0; |
43a73a50 | 1042 | unsigned int prefix = (msg->facility << 3) | msg->level; |
649e6ee3 | 1043 | |
3ce9a7c0 KS |
1044 | if (syslog) { |
1045 | if (buf) { | |
43a73a50 | 1046 | len += sprintf(buf, "<%u>", prefix); |
3ce9a7c0 KS |
1047 | } else { |
1048 | len += 3; | |
43a73a50 KS |
1049 | if (prefix > 999) |
1050 | len += 3; | |
1051 | else if (prefix > 99) | |
1052 | len += 2; | |
1053 | else if (prefix > 9) | |
3ce9a7c0 KS |
1054 | len++; |
1055 | } | |
1056 | } | |
649e6ee3 | 1057 | |
084681d1 | 1058 | len += print_time(msg->ts_nsec, buf ? buf + len : NULL); |
3ce9a7c0 | 1059 | return len; |
649e6ee3 KS |
1060 | } |
1061 | ||
62e32ac3 | 1062 | static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev, |
5becfb1d | 1063 | bool syslog, char *buf, size_t size) |
7ff9554b | 1064 | { |
3ce9a7c0 KS |
1065 | const char *text = log_text(msg); |
1066 | size_t text_size = msg->text_len; | |
5becfb1d KS |
1067 | bool prefix = true; |
1068 | bool newline = true; | |
3ce9a7c0 KS |
1069 | size_t len = 0; |
1070 | ||
5becfb1d KS |
1071 | if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) |
1072 | prefix = false; | |
1073 | ||
1074 | if (msg->flags & LOG_CONT) { | |
1075 | if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE)) | |
1076 | prefix = false; | |
1077 | ||
1078 | if (!(msg->flags & LOG_NEWLINE)) | |
1079 | newline = false; | |
1080 | } | |
1081 | ||
3ce9a7c0 KS |
1082 | do { |
1083 | const char *next = memchr(text, '\n', text_size); | |
1084 | size_t text_len; | |
1085 | ||
1086 | if (next) { | |
1087 | text_len = next - text; | |
1088 | next++; | |
1089 | text_size -= next - text; | |
1090 | } else { | |
1091 | text_len = text_size; | |
1092 | } | |
7ff9554b | 1093 | |
3ce9a7c0 KS |
1094 | if (buf) { |
1095 | if (print_prefix(msg, syslog, NULL) + | |
70498253 | 1096 | text_len + 1 >= size - len) |
3ce9a7c0 | 1097 | break; |
7ff9554b | 1098 | |
5becfb1d KS |
1099 | if (prefix) |
1100 | len += print_prefix(msg, syslog, buf + len); | |
3ce9a7c0 KS |
1101 | memcpy(buf + len, text, text_len); |
1102 | len += text_len; | |
5becfb1d KS |
1103 | if (next || newline) |
1104 | buf[len++] = '\n'; | |
3ce9a7c0 KS |
1105 | } else { |
1106 | /* SYSLOG_ACTION_* buffer size only calculation */ | |
5becfb1d KS |
1107 | if (prefix) |
1108 | len += print_prefix(msg, syslog, NULL); | |
1109 | len += text_len; | |
1110 | if (next || newline) | |
1111 | len++; | |
3ce9a7c0 | 1112 | } |
7ff9554b | 1113 | |
5becfb1d | 1114 | prefix = true; |
3ce9a7c0 KS |
1115 | text = next; |
1116 | } while (text); | |
7ff9554b | 1117 | |
7ff9554b KS |
1118 | return len; |
1119 | } | |
1120 | ||
1121 | static int syslog_print(char __user *buf, int size) | |
1122 | { | |
1123 | char *text; | |
62e32ac3 | 1124 | struct printk_log *msg; |
116e90b2 | 1125 | int len = 0; |
7ff9554b | 1126 | |
70498253 | 1127 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1128 | if (!text) |
1129 | return -ENOMEM; | |
1130 | ||
116e90b2 JB |
1131 | while (size > 0) { |
1132 | size_t n; | |
eb02dac9 | 1133 | size_t skip; |
116e90b2 JB |
1134 | |
1135 | raw_spin_lock_irq(&logbuf_lock); | |
1136 | if (syslog_seq < log_first_seq) { | |
1137 | /* messages are gone, move to first one */ | |
1138 | syslog_seq = log_first_seq; | |
1139 | syslog_idx = log_first_idx; | |
5becfb1d | 1140 | syslog_prev = 0; |
eb02dac9 | 1141 | syslog_partial = 0; |
116e90b2 JB |
1142 | } |
1143 | if (syslog_seq == log_next_seq) { | |
1144 | raw_spin_unlock_irq(&logbuf_lock); | |
1145 | break; | |
1146 | } | |
eb02dac9 KS |
1147 | |
1148 | skip = syslog_partial; | |
116e90b2 | 1149 | msg = log_from_idx(syslog_idx); |
70498253 KS |
1150 | n = msg_print_text(msg, syslog_prev, true, text, |
1151 | LOG_LINE_MAX + PREFIX_MAX); | |
eb02dac9 KS |
1152 | if (n - syslog_partial <= size) { |
1153 | /* message fits into buffer, move forward */ | |
116e90b2 JB |
1154 | syslog_idx = log_next(syslog_idx); |
1155 | syslog_seq++; | |
5becfb1d | 1156 | syslog_prev = msg->flags; |
eb02dac9 KS |
1157 | n -= syslog_partial; |
1158 | syslog_partial = 0; | |
1159 | } else if (!len){ | |
1160 | /* partial read(), remember position */ | |
1161 | n = size; | |
1162 | syslog_partial += n; | |
116e90b2 JB |
1163 | } else |
1164 | n = 0; | |
1165 | raw_spin_unlock_irq(&logbuf_lock); | |
1166 | ||
1167 | if (!n) | |
1168 | break; | |
1169 | ||
eb02dac9 | 1170 | if (copy_to_user(buf, text + skip, n)) { |
116e90b2 JB |
1171 | if (!len) |
1172 | len = -EFAULT; | |
1173 | break; | |
1174 | } | |
eb02dac9 KS |
1175 | |
1176 | len += n; | |
1177 | size -= n; | |
1178 | buf += n; | |
7ff9554b | 1179 | } |
7ff9554b KS |
1180 | |
1181 | kfree(text); | |
1182 | return len; | |
1183 | } | |
1184 | ||
1185 | static int syslog_print_all(char __user *buf, int size, bool clear) | |
1186 | { | |
1187 | char *text; | |
1188 | int len = 0; | |
1189 | ||
70498253 | 1190 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1191 | if (!text) |
1192 | return -ENOMEM; | |
1193 | ||
1194 | raw_spin_lock_irq(&logbuf_lock); | |
1195 | if (buf) { | |
1196 | u64 next_seq; | |
1197 | u64 seq; | |
1198 | u32 idx; | |
5becfb1d | 1199 | enum log_flags prev; |
7ff9554b KS |
1200 | |
1201 | if (clear_seq < log_first_seq) { | |
1202 | /* messages are gone, move to first available one */ | |
1203 | clear_seq = log_first_seq; | |
1204 | clear_idx = log_first_idx; | |
1205 | } | |
1206 | ||
1207 | /* | |
1208 | * Find first record that fits, including all following records, | |
1209 | * into the user-provided buffer for this dump. | |
e2ae715d | 1210 | */ |
7ff9554b KS |
1211 | seq = clear_seq; |
1212 | idx = clear_idx; | |
5becfb1d | 1213 | prev = 0; |
7ff9554b | 1214 | while (seq < log_next_seq) { |
62e32ac3 | 1215 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1216 | |
5becfb1d | 1217 | len += msg_print_text(msg, prev, true, NULL, 0); |
e3756477 | 1218 | prev = msg->flags; |
7ff9554b KS |
1219 | idx = log_next(idx); |
1220 | seq++; | |
1221 | } | |
e2ae715d KS |
1222 | |
1223 | /* move first record forward until length fits into the buffer */ | |
7ff9554b KS |
1224 | seq = clear_seq; |
1225 | idx = clear_idx; | |
5becfb1d | 1226 | prev = 0; |
7ff9554b | 1227 | while (len > size && seq < log_next_seq) { |
62e32ac3 | 1228 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1229 | |
5becfb1d | 1230 | len -= msg_print_text(msg, prev, true, NULL, 0); |
e3756477 | 1231 | prev = msg->flags; |
7ff9554b KS |
1232 | idx = log_next(idx); |
1233 | seq++; | |
1234 | } | |
1235 | ||
e2ae715d | 1236 | /* last message fitting into this dump */ |
7ff9554b KS |
1237 | next_seq = log_next_seq; |
1238 | ||
1239 | len = 0; | |
1240 | while (len >= 0 && seq < next_seq) { | |
62e32ac3 | 1241 | struct printk_log *msg = log_from_idx(idx); |
7ff9554b KS |
1242 | int textlen; |
1243 | ||
70498253 KS |
1244 | textlen = msg_print_text(msg, prev, true, text, |
1245 | LOG_LINE_MAX + PREFIX_MAX); | |
7ff9554b KS |
1246 | if (textlen < 0) { |
1247 | len = textlen; | |
1248 | break; | |
1249 | } | |
1250 | idx = log_next(idx); | |
1251 | seq++; | |
5becfb1d | 1252 | prev = msg->flags; |
7ff9554b KS |
1253 | |
1254 | raw_spin_unlock_irq(&logbuf_lock); | |
1255 | if (copy_to_user(buf + len, text, textlen)) | |
1256 | len = -EFAULT; | |
1257 | else | |
1258 | len += textlen; | |
1259 | raw_spin_lock_irq(&logbuf_lock); | |
1260 | ||
1261 | if (seq < log_first_seq) { | |
1262 | /* messages are gone, move to next one */ | |
1263 | seq = log_first_seq; | |
1264 | idx = log_first_idx; | |
5becfb1d | 1265 | prev = 0; |
7ff9554b KS |
1266 | } |
1267 | } | |
1268 | } | |
1269 | ||
1270 | if (clear) { | |
1271 | clear_seq = log_next_seq; | |
1272 | clear_idx = log_next_idx; | |
1273 | } | |
1274 | raw_spin_unlock_irq(&logbuf_lock); | |
1275 | ||
1276 | kfree(text); | |
1277 | return len; | |
1278 | } | |
1279 | ||
00234592 | 1280 | int do_syslog(int type, char __user *buf, int len, bool from_file) |
1da177e4 | 1281 | { |
7ff9554b | 1282 | bool clear = false; |
a39d4a85 | 1283 | static int saved_console_loglevel = LOGLEVEL_DEFAULT; |
ee24aebf | 1284 | int error; |
1da177e4 | 1285 | |
ee24aebf LT |
1286 | error = check_syslog_permissions(type, from_file); |
1287 | if (error) | |
1288 | goto out; | |
12b3052c EP |
1289 | |
1290 | error = security_syslog(type); | |
1da177e4 LT |
1291 | if (error) |
1292 | return error; | |
1293 | ||
1294 | switch (type) { | |
d78ca3cd | 1295 | case SYSLOG_ACTION_CLOSE: /* Close log */ |
1da177e4 | 1296 | break; |
d78ca3cd | 1297 | case SYSLOG_ACTION_OPEN: /* Open log */ |
1da177e4 | 1298 | break; |
d78ca3cd | 1299 | case SYSLOG_ACTION_READ: /* Read from log */ |
1da177e4 LT |
1300 | error = -EINVAL; |
1301 | if (!buf || len < 0) | |
1302 | goto out; | |
1303 | error = 0; | |
1304 | if (!len) | |
1305 | goto out; | |
1306 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1307 | error = -EFAULT; | |
1308 | goto out; | |
1309 | } | |
40dc5651 | 1310 | error = wait_event_interruptible(log_wait, |
7ff9554b | 1311 | syslog_seq != log_next_seq); |
cb424ffe | 1312 | if (error) |
1da177e4 | 1313 | goto out; |
7ff9554b | 1314 | error = syslog_print(buf, len); |
1da177e4 | 1315 | break; |
d78ca3cd KC |
1316 | /* Read/clear last kernel messages */ |
1317 | case SYSLOG_ACTION_READ_CLEAR: | |
7ff9554b | 1318 | clear = true; |
1da177e4 | 1319 | /* FALL THRU */ |
d78ca3cd KC |
1320 | /* Read last kernel messages */ |
1321 | case SYSLOG_ACTION_READ_ALL: | |
1da177e4 LT |
1322 | error = -EINVAL; |
1323 | if (!buf || len < 0) | |
1324 | goto out; | |
1325 | error = 0; | |
1326 | if (!len) | |
1327 | goto out; | |
1328 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1329 | error = -EFAULT; | |
1330 | goto out; | |
1331 | } | |
7ff9554b | 1332 | error = syslog_print_all(buf, len, clear); |
1da177e4 | 1333 | break; |
d78ca3cd KC |
1334 | /* Clear ring buffer */ |
1335 | case SYSLOG_ACTION_CLEAR: | |
7ff9554b | 1336 | syslog_print_all(NULL, 0, true); |
4661e356 | 1337 | break; |
d78ca3cd KC |
1338 | /* Disable logging to console */ |
1339 | case SYSLOG_ACTION_CONSOLE_OFF: | |
a39d4a85 | 1340 | if (saved_console_loglevel == LOGLEVEL_DEFAULT) |
1aaad49e | 1341 | saved_console_loglevel = console_loglevel; |
1da177e4 LT |
1342 | console_loglevel = minimum_console_loglevel; |
1343 | break; | |
d78ca3cd KC |
1344 | /* Enable logging to console */ |
1345 | case SYSLOG_ACTION_CONSOLE_ON: | |
a39d4a85 | 1346 | if (saved_console_loglevel != LOGLEVEL_DEFAULT) { |
1aaad49e | 1347 | console_loglevel = saved_console_loglevel; |
a39d4a85 | 1348 | saved_console_loglevel = LOGLEVEL_DEFAULT; |
1aaad49e | 1349 | } |
1da177e4 | 1350 | break; |
d78ca3cd KC |
1351 | /* Set level of messages printed to console */ |
1352 | case SYSLOG_ACTION_CONSOLE_LEVEL: | |
1da177e4 LT |
1353 | error = -EINVAL; |
1354 | if (len < 1 || len > 8) | |
1355 | goto out; | |
1356 | if (len < minimum_console_loglevel) | |
1357 | len = minimum_console_loglevel; | |
1358 | console_loglevel = len; | |
1aaad49e | 1359 | /* Implicitly re-enable logging to console */ |
a39d4a85 | 1360 | saved_console_loglevel = LOGLEVEL_DEFAULT; |
1da177e4 LT |
1361 | error = 0; |
1362 | break; | |
d78ca3cd KC |
1363 | /* Number of chars in the log buffer */ |
1364 | case SYSLOG_ACTION_SIZE_UNREAD: | |
7ff9554b KS |
1365 | raw_spin_lock_irq(&logbuf_lock); |
1366 | if (syslog_seq < log_first_seq) { | |
1367 | /* messages are gone, move to first one */ | |
1368 | syslog_seq = log_first_seq; | |
1369 | syslog_idx = log_first_idx; | |
5becfb1d | 1370 | syslog_prev = 0; |
eb02dac9 | 1371 | syslog_partial = 0; |
7ff9554b KS |
1372 | } |
1373 | if (from_file) { | |
1374 | /* | |
1375 | * Short-cut for poll(/"proc/kmsg") which simply checks | |
1376 | * for pending data, not the size; return the count of | |
1377 | * records, not the length. | |
1378 | */ | |
e97e1267 | 1379 | error = log_next_seq - syslog_seq; |
7ff9554b | 1380 | } else { |
5becfb1d KS |
1381 | u64 seq = syslog_seq; |
1382 | u32 idx = syslog_idx; | |
1383 | enum log_flags prev = syslog_prev; | |
7ff9554b KS |
1384 | |
1385 | error = 0; | |
7ff9554b | 1386 | while (seq < log_next_seq) { |
62e32ac3 | 1387 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1388 | |
5becfb1d | 1389 | error += msg_print_text(msg, prev, true, NULL, 0); |
7ff9554b KS |
1390 | idx = log_next(idx); |
1391 | seq++; | |
5becfb1d | 1392 | prev = msg->flags; |
7ff9554b | 1393 | } |
eb02dac9 | 1394 | error -= syslog_partial; |
7ff9554b KS |
1395 | } |
1396 | raw_spin_unlock_irq(&logbuf_lock); | |
1da177e4 | 1397 | break; |
d78ca3cd KC |
1398 | /* Size of the log buffer */ |
1399 | case SYSLOG_ACTION_SIZE_BUFFER: | |
1da177e4 LT |
1400 | error = log_buf_len; |
1401 | break; | |
1402 | default: | |
1403 | error = -EINVAL; | |
1404 | break; | |
1405 | } | |
1406 | out: | |
1407 | return error; | |
1408 | } | |
1409 | ||
1e7bfb21 | 1410 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
1da177e4 | 1411 | { |
637241a9 | 1412 | return do_syslog(type, buf, len, SYSLOG_FROM_READER); |
1da177e4 LT |
1413 | } |
1414 | ||
1da177e4 LT |
1415 | /* |
1416 | * Call the console drivers, asking them to write out | |
1417 | * log_buf[start] to log_buf[end - 1]. | |
ac751efa | 1418 | * The console_lock must be held. |
1da177e4 | 1419 | */ |
7ff9554b | 1420 | static void call_console_drivers(int level, const char *text, size_t len) |
1da177e4 | 1421 | { |
7ff9554b | 1422 | struct console *con; |
1da177e4 | 1423 | |
07c65f4d | 1424 | trace_console(text, len); |
7ff9554b KS |
1425 | |
1426 | if (level >= console_loglevel && !ignore_loglevel) | |
1427 | return; | |
1428 | if (!console_drivers) | |
1429 | return; | |
1430 | ||
1431 | for_each_console(con) { | |
1432 | if (exclusive_console && con != exclusive_console) | |
1433 | continue; | |
1434 | if (!(con->flags & CON_ENABLED)) | |
1435 | continue; | |
1436 | if (!con->write) | |
1437 | continue; | |
1438 | if (!cpu_online(smp_processor_id()) && | |
1439 | !(con->flags & CON_ANYTIME)) | |
1440 | continue; | |
1441 | con->write(con, text, len); | |
1442 | } | |
1da177e4 LT |
1443 | } |
1444 | ||
1445 | /* | |
205bd3d2 JP |
1446 | * Zap console related locks when oopsing. |
1447 | * To leave time for slow consoles to print a full oops, | |
1448 | * only zap at most once every 30 seconds. | |
1da177e4 LT |
1449 | */ |
1450 | static void zap_locks(void) | |
1451 | { | |
1452 | static unsigned long oops_timestamp; | |
1453 | ||
1454 | if (time_after_eq(jiffies, oops_timestamp) && | |
205bd3d2 | 1455 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
1da177e4 LT |
1456 | return; |
1457 | ||
1458 | oops_timestamp = jiffies; | |
1459 | ||
94d24fc4 | 1460 | debug_locks_off(); |
1da177e4 | 1461 | /* If a crash is occurring, make sure we can't deadlock */ |
07354eb1 | 1462 | raw_spin_lock_init(&logbuf_lock); |
1da177e4 | 1463 | /* And make sure that we print immediately */ |
5b8c4f23 | 1464 | sema_init(&console_sem, 1); |
1da177e4 LT |
1465 | } |
1466 | ||
608873ca JK |
1467 | /* |
1468 | * Check if we have any console that is capable of printing while cpu is | |
1469 | * booting or shutting down. Requires console_sem. | |
1470 | */ | |
76a8ad29 ME |
1471 | static int have_callable_console(void) |
1472 | { | |
1473 | struct console *con; | |
1474 | ||
4d091611 | 1475 | for_each_console(con) |
76a8ad29 ME |
1476 | if (con->flags & CON_ANYTIME) |
1477 | return 1; | |
1478 | ||
1479 | return 0; | |
1480 | } | |
1481 | ||
266c2e0a LT |
1482 | /* |
1483 | * Can we actually use the console at this time on this cpu? | |
1484 | * | |
5874af20 JK |
1485 | * Console drivers may assume that per-cpu resources have been allocated. So |
1486 | * unless they're explicitly marked as being able to cope (CON_ANYTIME) don't | |
1487 | * call them until this CPU is officially up. | |
266c2e0a LT |
1488 | */ |
1489 | static inline int can_use_console(unsigned int cpu) | |
1490 | { | |
1491 | return cpu_online(cpu) || have_callable_console(); | |
1492 | } | |
1493 | ||
1494 | /* | |
1495 | * Try to get console ownership to actually show the kernel | |
1496 | * messages from a 'printk'. Return true (and with the | |
ac751efa | 1497 | * console_lock held, and 'console_locked' set) if it |
266c2e0a | 1498 | * is successful, false otherwise. |
266c2e0a | 1499 | */ |
5874af20 | 1500 | static int console_trylock_for_printk(void) |
266c2e0a | 1501 | { |
5874af20 JK |
1502 | unsigned int cpu = smp_processor_id(); |
1503 | ||
608873ca JK |
1504 | if (!console_trylock()) |
1505 | return 0; | |
1506 | /* | |
1507 | * If we can't use the console, we need to release the console | |
1508 | * semaphore by hand to avoid flushing the buffer. We need to hold the | |
1509 | * console semaphore in order to do this test safely. | |
1510 | */ | |
1511 | if (!can_use_console(cpu)) { | |
1512 | console_locked = 0; | |
bd8d7cf5 | 1513 | up_console_sem(); |
608873ca JK |
1514 | return 0; |
1515 | } | |
1516 | return 1; | |
266c2e0a | 1517 | } |
32a76006 | 1518 | |
af91322e DY |
1519 | int printk_delay_msec __read_mostly; |
1520 | ||
1521 | static inline void printk_delay(void) | |
1522 | { | |
1523 | if (unlikely(printk_delay_msec)) { | |
1524 | int m = printk_delay_msec; | |
1525 | ||
1526 | while (m--) { | |
1527 | mdelay(1); | |
1528 | touch_nmi_watchdog(); | |
1529 | } | |
1530 | } | |
1531 | } | |
1532 | ||
084681d1 KS |
1533 | /* |
1534 | * Continuation lines are buffered, and not committed to the record buffer | |
1535 | * until the line is complete, or a race forces it. The line fragments | |
1536 | * though, are printed immediately to the consoles to ensure everything has | |
1537 | * reached the console in case of a kernel crash. | |
1538 | */ | |
1539 | static struct cont { | |
1540 | char buf[LOG_LINE_MAX]; | |
1541 | size_t len; /* length == 0 means unused buffer */ | |
1542 | size_t cons; /* bytes written to console */ | |
1543 | struct task_struct *owner; /* task of first print*/ | |
1544 | u64 ts_nsec; /* time of first print */ | |
1545 | u8 level; /* log level of first message */ | |
0b90fec3 | 1546 | u8 facility; /* log facility of first message */ |
eab07260 | 1547 | enum log_flags flags; /* prefix, newline flags */ |
084681d1 KS |
1548 | bool flushed:1; /* buffer sealed and committed */ |
1549 | } cont; | |
1550 | ||
70498253 | 1551 | static void cont_flush(enum log_flags flags) |
084681d1 KS |
1552 | { |
1553 | if (cont.flushed) | |
1554 | return; | |
1555 | if (cont.len == 0) | |
1556 | return; | |
1557 | ||
eab07260 KS |
1558 | if (cont.cons) { |
1559 | /* | |
1560 | * If a fragment of this line was directly flushed to the | |
1561 | * console; wait for the console to pick up the rest of the | |
1562 | * line. LOG_NOCONS suppresses a duplicated output. | |
1563 | */ | |
1564 | log_store(cont.facility, cont.level, flags | LOG_NOCONS, | |
1565 | cont.ts_nsec, NULL, 0, cont.buf, cont.len); | |
1566 | cont.flags = flags; | |
1567 | cont.flushed = true; | |
1568 | } else { | |
1569 | /* | |
1570 | * If no fragment of this line ever reached the console, | |
1571 | * just submit it to the store and free the buffer. | |
1572 | */ | |
1573 | log_store(cont.facility, cont.level, flags, 0, | |
1574 | NULL, 0, cont.buf, cont.len); | |
1575 | cont.len = 0; | |
1576 | } | |
084681d1 KS |
1577 | } |
1578 | ||
1579 | static bool cont_add(int facility, int level, const char *text, size_t len) | |
1580 | { | |
1581 | if (cont.len && cont.flushed) | |
1582 | return false; | |
1583 | ||
1584 | if (cont.len + len > sizeof(cont.buf)) { | |
70498253 KS |
1585 | /* the line gets too long, split it up in separate records */ |
1586 | cont_flush(LOG_CONT); | |
084681d1 KS |
1587 | return false; |
1588 | } | |
1589 | ||
1590 | if (!cont.len) { | |
1591 | cont.facility = facility; | |
1592 | cont.level = level; | |
1593 | cont.owner = current; | |
1594 | cont.ts_nsec = local_clock(); | |
eab07260 | 1595 | cont.flags = 0; |
084681d1 KS |
1596 | cont.cons = 0; |
1597 | cont.flushed = false; | |
1598 | } | |
1599 | ||
1600 | memcpy(cont.buf + cont.len, text, len); | |
1601 | cont.len += len; | |
eab07260 KS |
1602 | |
1603 | if (cont.len > (sizeof(cont.buf) * 80) / 100) | |
1604 | cont_flush(LOG_CONT); | |
1605 | ||
084681d1 KS |
1606 | return true; |
1607 | } | |
1608 | ||
1609 | static size_t cont_print_text(char *text, size_t size) | |
1610 | { | |
1611 | size_t textlen = 0; | |
1612 | size_t len; | |
1613 | ||
eab07260 | 1614 | if (cont.cons == 0 && (console_prev & LOG_NEWLINE)) { |
084681d1 KS |
1615 | textlen += print_time(cont.ts_nsec, text); |
1616 | size -= textlen; | |
1617 | } | |
1618 | ||
1619 | len = cont.len - cont.cons; | |
1620 | if (len > 0) { | |
1621 | if (len+1 > size) | |
1622 | len = size-1; | |
1623 | memcpy(text + textlen, cont.buf + cont.cons, len); | |
1624 | textlen += len; | |
1625 | cont.cons = cont.len; | |
1626 | } | |
1627 | ||
1628 | if (cont.flushed) { | |
eab07260 KS |
1629 | if (cont.flags & LOG_NEWLINE) |
1630 | text[textlen++] = '\n'; | |
084681d1 KS |
1631 | /* got everything, release buffer */ |
1632 | cont.len = 0; | |
1633 | } | |
1634 | return textlen; | |
1635 | } | |
1636 | ||
7ff9554b KS |
1637 | asmlinkage int vprintk_emit(int facility, int level, |
1638 | const char *dict, size_t dictlen, | |
1639 | const char *fmt, va_list args) | |
1da177e4 | 1640 | { |
7ff9554b | 1641 | static int recursion_bug; |
7ff9554b KS |
1642 | static char textbuf[LOG_LINE_MAX]; |
1643 | char *text = textbuf; | |
458df9fd | 1644 | size_t text_len = 0; |
5becfb1d | 1645 | enum log_flags lflags = 0; |
ac60ad74 | 1646 | unsigned long flags; |
32a76006 | 1647 | int this_cpu; |
7ff9554b | 1648 | int printed_len = 0; |
458df9fd | 1649 | bool in_sched = false; |
608873ca | 1650 | /* cpu currently holding logbuf_lock in this function */ |
f099755d | 1651 | static unsigned int logbuf_cpu = UINT_MAX; |
608873ca | 1652 | |
a39d4a85 JP |
1653 | if (level == LOGLEVEL_SCHED) { |
1654 | level = LOGLEVEL_DEFAULT; | |
458df9fd SR |
1655 | in_sched = true; |
1656 | } | |
1da177e4 | 1657 | |
2fa72c8f | 1658 | boot_delay_msec(level); |
af91322e | 1659 | printk_delay(); |
bfe8df3d | 1660 | |
1da177e4 | 1661 | /* This stops the holder of console_sem just where we want him */ |
1a9a8aef | 1662 | local_irq_save(flags); |
32a76006 IM |
1663 | this_cpu = smp_processor_id(); |
1664 | ||
1665 | /* | |
1666 | * Ouch, printk recursed into itself! | |
1667 | */ | |
7ff9554b | 1668 | if (unlikely(logbuf_cpu == this_cpu)) { |
32a76006 IM |
1669 | /* |
1670 | * If a crash is occurring during printk() on this CPU, | |
1671 | * then try to get the crash message out but make sure | |
1672 | * we can't deadlock. Otherwise just return to avoid the | |
1673 | * recursion and return - but flag the recursion so that | |
1674 | * it can be printed at the next appropriate moment: | |
1675 | */ | |
94d24fc4 | 1676 | if (!oops_in_progress && !lockdep_recursing(current)) { |
3b8945e8 | 1677 | recursion_bug = 1; |
5874af20 JK |
1678 | local_irq_restore(flags); |
1679 | return 0; | |
32a76006 IM |
1680 | } |
1681 | zap_locks(); | |
1682 | } | |
1683 | ||
a0f1ccfd | 1684 | lockdep_off(); |
07354eb1 | 1685 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 1686 | logbuf_cpu = this_cpu; |
1da177e4 | 1687 | |
000a7d66 | 1688 | if (unlikely(recursion_bug)) { |
7ff9554b KS |
1689 | static const char recursion_msg[] = |
1690 | "BUG: recent printk recursion!"; | |
1691 | ||
3b8945e8 | 1692 | recursion_bug = 0; |
7ff9554b | 1693 | /* emit KERN_CRIT message */ |
034633cc | 1694 | printed_len += log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, |
000a7d66 PP |
1695 | NULL, 0, recursion_msg, |
1696 | strlen(recursion_msg)); | |
32a76006 | 1697 | } |
1da177e4 | 1698 | |
7ff9554b KS |
1699 | /* |
1700 | * The printf needs to come first; we need the syslog | |
1701 | * prefix which might be passed-in as a parameter. | |
1702 | */ | |
98e35f58 | 1703 | text_len = vscnprintf(text, sizeof(textbuf), fmt, args); |
5fd29d6c | 1704 | |
7ff9554b | 1705 | /* mark and strip a trailing newline */ |
c313af14 KS |
1706 | if (text_len && text[text_len-1] == '\n') { |
1707 | text_len--; | |
5becfb1d | 1708 | lflags |= LOG_NEWLINE; |
7ff9554b | 1709 | } |
9d90c8d9 | 1710 | |
088a52aa JP |
1711 | /* strip kernel syslog prefix and extract log level or control flags */ |
1712 | if (facility == 0) { | |
1713 | int kern_level = printk_get_level(text); | |
1714 | ||
1715 | if (kern_level) { | |
1716 | const char *end_of_header = printk_skip_level(text); | |
1717 | switch (kern_level) { | |
1718 | case '0' ... '7': | |
a39d4a85 | 1719 | if (level == LOGLEVEL_DEFAULT) |
088a52aa | 1720 | level = kern_level - '0'; |
a39d4a85 | 1721 | /* fallthrough */ |
088a52aa JP |
1722 | case 'd': /* KERN_DEFAULT */ |
1723 | lflags |= LOG_PREFIX; | |
088a52aa | 1724 | } |
e8c42d36 PM |
1725 | /* |
1726 | * No need to check length here because vscnprintf | |
1727 | * put '\0' at the end of the string. Only valid and | |
1728 | * newly printed level is detected. | |
1729 | */ | |
088a52aa JP |
1730 | text_len -= end_of_header - text; |
1731 | text = (char *)end_of_header; | |
5fd29d6c LT |
1732 | } |
1733 | } | |
1734 | ||
a39d4a85 | 1735 | if (level == LOGLEVEL_DEFAULT) |
c313af14 | 1736 | level = default_message_loglevel; |
9d90c8d9 | 1737 | |
5becfb1d KS |
1738 | if (dict) |
1739 | lflags |= LOG_PREFIX|LOG_NEWLINE; | |
ac60ad74 | 1740 | |
5becfb1d | 1741 | if (!(lflags & LOG_NEWLINE)) { |
084681d1 KS |
1742 | /* |
1743 | * Flush the conflicting buffer. An earlier newline was missing, | |
1744 | * or another task also prints continuation lines. | |
1745 | */ | |
5becfb1d | 1746 | if (cont.len && (lflags & LOG_PREFIX || cont.owner != current)) |
eab07260 | 1747 | cont_flush(LOG_NEWLINE); |
c313af14 | 1748 | |
084681d1 | 1749 | /* buffer line if possible, otherwise store it right away */ |
034633cc PM |
1750 | if (cont_add(facility, level, text, text_len)) |
1751 | printed_len += text_len; | |
1752 | else | |
1753 | printed_len += log_store(facility, level, | |
1754 | lflags | LOG_CONT, 0, | |
1755 | dict, dictlen, text, text_len); | |
5c5d5ca5 | 1756 | } else { |
084681d1 | 1757 | bool stored = false; |
c313af14 | 1758 | |
084681d1 | 1759 | /* |
d3620822 SR |
1760 | * If an earlier newline was missing and it was the same task, |
1761 | * either merge it with the current buffer and flush, or if | |
1762 | * there was a race with interrupts (prefix == true) then just | |
1763 | * flush it out and store this line separately. | |
1d3fa370 AK |
1764 | * If the preceding printk was from a different task and missed |
1765 | * a newline, flush and append the newline. | |
084681d1 | 1766 | */ |
1d3fa370 AK |
1767 | if (cont.len) { |
1768 | if (cont.owner == current && !(lflags & LOG_PREFIX)) | |
1769 | stored = cont_add(facility, level, text, | |
1770 | text_len); | |
eab07260 | 1771 | cont_flush(LOG_NEWLINE); |
c313af14 | 1772 | } |
084681d1 | 1773 | |
034633cc PM |
1774 | if (stored) |
1775 | printed_len += text_len; | |
1776 | else | |
1777 | printed_len += log_store(facility, level, lflags, 0, | |
1778 | dict, dictlen, text, text_len); | |
1da177e4 LT |
1779 | } |
1780 | ||
608873ca JK |
1781 | logbuf_cpu = UINT_MAX; |
1782 | raw_spin_unlock(&logbuf_lock); | |
5874af20 JK |
1783 | lockdep_on(); |
1784 | local_irq_restore(flags); | |
939f04be | 1785 | |
458df9fd | 1786 | /* If called from the scheduler, we can not call up(). */ |
d18bbc21 | 1787 | if (!in_sched) { |
5874af20 JK |
1788 | lockdep_off(); |
1789 | /* | |
1790 | * Disable preemption to avoid being preempted while holding | |
1791 | * console_sem which would prevent anyone from printing to | |
1792 | * console | |
1793 | */ | |
1794 | preempt_disable(); | |
1795 | ||
d18bbc21 AM |
1796 | /* |
1797 | * Try to acquire and then immediately release the console | |
1798 | * semaphore. The release will print out buffers and wake up | |
1799 | * /dev/kmsg and syslog() users. | |
1800 | */ | |
5874af20 | 1801 | if (console_trylock_for_printk()) |
d18bbc21 | 1802 | console_unlock(); |
5874af20 JK |
1803 | preempt_enable(); |
1804 | lockdep_on(); | |
d18bbc21 | 1805 | } |
76a8ad29 | 1806 | |
1da177e4 LT |
1807 | return printed_len; |
1808 | } | |
7ff9554b KS |
1809 | EXPORT_SYMBOL(vprintk_emit); |
1810 | ||
1811 | asmlinkage int vprintk(const char *fmt, va_list args) | |
1812 | { | |
a39d4a85 | 1813 | return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args); |
7ff9554b | 1814 | } |
1da177e4 LT |
1815 | EXPORT_SYMBOL(vprintk); |
1816 | ||
7ff9554b KS |
1817 | asmlinkage int printk_emit(int facility, int level, |
1818 | const char *dict, size_t dictlen, | |
1819 | const char *fmt, ...) | |
1820 | { | |
1821 | va_list args; | |
1822 | int r; | |
1823 | ||
1824 | va_start(args, fmt); | |
1825 | r = vprintk_emit(facility, level, dict, dictlen, fmt, args); | |
1826 | va_end(args); | |
1827 | ||
1828 | return r; | |
1829 | } | |
1830 | EXPORT_SYMBOL(printk_emit); | |
1831 | ||
afdc34a3 SRRH |
1832 | int vprintk_default(const char *fmt, va_list args) |
1833 | { | |
1834 | int r; | |
1835 | ||
1836 | #ifdef CONFIG_KGDB_KDB | |
1837 | if (unlikely(kdb_trap_printk)) { | |
f7d4ca8b | 1838 | r = vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args); |
afdc34a3 SRRH |
1839 | return r; |
1840 | } | |
1841 | #endif | |
350e4f49 | 1842 | r = vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args); |
afdc34a3 SRRH |
1843 | |
1844 | return r; | |
1845 | } | |
1846 | EXPORT_SYMBOL_GPL(vprintk_default); | |
1847 | ||
1848 | /* | |
1849 | * This allows printk to be diverted to another function per cpu. | |
1850 | * This is useful for calling printk functions from within NMI | |
1851 | * without worrying about race conditions that can lock up the | |
1852 | * box. | |
1853 | */ | |
1854 | DEFINE_PER_CPU(printk_func_t, printk_func) = vprintk_default; | |
1855 | ||
7ff9554b KS |
1856 | /** |
1857 | * printk - print a kernel message | |
1858 | * @fmt: format string | |
1859 | * | |
1860 | * This is printk(). It can be called from any context. We want it to work. | |
1861 | * | |
1862 | * We try to grab the console_lock. If we succeed, it's easy - we log the | |
1863 | * output and call the console drivers. If we fail to get the semaphore, we | |
1864 | * place the output into the log buffer and return. The current holder of | |
1865 | * the console_sem will notice the new output in console_unlock(); and will | |
1866 | * send it to the consoles before releasing the lock. | |
1867 | * | |
1868 | * One effect of this deferred printing is that code which calls printk() and | |
1869 | * then changes console_loglevel may break. This is because console_loglevel | |
1870 | * is inspected when the actual printing occurs. | |
1871 | * | |
1872 | * See also: | |
1873 | * printf(3) | |
1874 | * | |
1875 | * See the vsnprintf() documentation for format string extensions over C99. | |
1876 | */ | |
722a9f92 | 1877 | asmlinkage __visible int printk(const char *fmt, ...) |
7ff9554b | 1878 | { |
afdc34a3 | 1879 | printk_func_t vprintk_func; |
7ff9554b KS |
1880 | va_list args; |
1881 | int r; | |
1882 | ||
7ff9554b | 1883 | va_start(args, fmt); |
1fb8915b SRRH |
1884 | |
1885 | /* | |
1886 | * If a caller overrides the per_cpu printk_func, then it needs | |
1887 | * to disable preemption when calling printk(). Otherwise | |
1888 | * the printk_func should be set to the default. No need to | |
1889 | * disable preemption here. | |
1890 | */ | |
afdc34a3 SRRH |
1891 | vprintk_func = this_cpu_read(printk_func); |
1892 | r = vprintk_func(fmt, args); | |
1fb8915b | 1893 | |
7ff9554b KS |
1894 | va_end(args); |
1895 | ||
1896 | return r; | |
1897 | } | |
1898 | EXPORT_SYMBOL(printk); | |
7f3a781d | 1899 | |
96efedf1 | 1900 | #else /* CONFIG_PRINTK */ |
d59745ce | 1901 | |
70498253 KS |
1902 | #define LOG_LINE_MAX 0 |
1903 | #define PREFIX_MAX 0 | |
249771b8 | 1904 | |
96efedf1 KS |
1905 | static u64 syslog_seq; |
1906 | static u32 syslog_idx; | |
eab07260 KS |
1907 | static u64 console_seq; |
1908 | static u32 console_idx; | |
96efedf1 KS |
1909 | static enum log_flags syslog_prev; |
1910 | static u64 log_first_seq; | |
1911 | static u32 log_first_idx; | |
1912 | static u64 log_next_seq; | |
eab07260 | 1913 | static enum log_flags console_prev; |
084681d1 KS |
1914 | static struct cont { |
1915 | size_t len; | |
1916 | size_t cons; | |
1917 | u8 level; | |
1918 | bool flushed:1; | |
1919 | } cont; | |
62e32ac3 | 1920 | static struct printk_log *log_from_idx(u32 idx) { return NULL; } |
7f3a781d | 1921 | static u32 log_next(u32 idx) { return 0; } |
7f3a781d | 1922 | static void call_console_drivers(int level, const char *text, size_t len) {} |
62e32ac3 | 1923 | static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev, |
5becfb1d | 1924 | bool syslog, char *buf, size_t size) { return 0; } |
084681d1 | 1925 | static size_t cont_print_text(char *text, size_t size) { return 0; } |
d59745ce | 1926 | |
04b74b27 SRRH |
1927 | /* Still needs to be defined for users */ |
1928 | DEFINE_PER_CPU(printk_func_t, printk_func); | |
1929 | ||
7f3a781d | 1930 | #endif /* CONFIG_PRINTK */ |
d59745ce | 1931 | |
d0380e6c TG |
1932 | #ifdef CONFIG_EARLY_PRINTK |
1933 | struct console *early_console; | |
1934 | ||
722a9f92 | 1935 | asmlinkage __visible void early_printk(const char *fmt, ...) |
d0380e6c TG |
1936 | { |
1937 | va_list ap; | |
1dc6244b JP |
1938 | char buf[512]; |
1939 | int n; | |
1940 | ||
1941 | if (!early_console) | |
1942 | return; | |
d0380e6c TG |
1943 | |
1944 | va_start(ap, fmt); | |
1dc6244b | 1945 | n = vscnprintf(buf, sizeof(buf), fmt, ap); |
d0380e6c | 1946 | va_end(ap); |
1dc6244b JP |
1947 | |
1948 | early_console->write(early_console, buf, n); | |
d0380e6c TG |
1949 | } |
1950 | #endif | |
1951 | ||
f7511d5f ST |
1952 | static int __add_preferred_console(char *name, int idx, char *options, |
1953 | char *brl_options) | |
1954 | { | |
1955 | struct console_cmdline *c; | |
1956 | int i; | |
1957 | ||
1958 | /* | |
1959 | * See if this tty is not yet registered, and | |
1960 | * if we have a slot free. | |
1961 | */ | |
23475408 JP |
1962 | for (i = 0, c = console_cmdline; |
1963 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
1964 | i++, c++) { | |
1965 | if (strcmp(c->name, name) == 0 && c->index == idx) { | |
1966 | if (!brl_options) | |
1967 | selected_console = i; | |
1968 | return 0; | |
f7511d5f | 1969 | } |
23475408 | 1970 | } |
f7511d5f ST |
1971 | if (i == MAX_CMDLINECONSOLES) |
1972 | return -E2BIG; | |
1973 | if (!brl_options) | |
1974 | selected_console = i; | |
f7511d5f ST |
1975 | strlcpy(c->name, name, sizeof(c->name)); |
1976 | c->options = options; | |
bbeddf52 JP |
1977 | braille_set_options(c, brl_options); |
1978 | ||
f7511d5f ST |
1979 | c->index = idx; |
1980 | return 0; | |
1981 | } | |
2ea1c539 | 1982 | /* |
0b90fec3 AE |
1983 | * Set up a console. Called via do_early_param() in init/main.c |
1984 | * for each "console=" parameter in the boot command line. | |
2ea1c539 JB |
1985 | */ |
1986 | static int __init console_setup(char *str) | |
1987 | { | |
0b90fec3 | 1988 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for "ttyS" */ |
f7511d5f | 1989 | char *s, *options, *brl_options = NULL; |
2ea1c539 JB |
1990 | int idx; |
1991 | ||
bbeddf52 JP |
1992 | if (_braille_console_setup(&str, &brl_options)) |
1993 | return 1; | |
f7511d5f | 1994 | |
2ea1c539 JB |
1995 | /* |
1996 | * Decode str into name, index, options. | |
1997 | */ | |
1998 | if (str[0] >= '0' && str[0] <= '9') { | |
eaa944af YL |
1999 | strcpy(buf, "ttyS"); |
2000 | strncpy(buf + 4, str, sizeof(buf) - 5); | |
2ea1c539 | 2001 | } else { |
eaa944af | 2002 | strncpy(buf, str, sizeof(buf) - 1); |
2ea1c539 | 2003 | } |
eaa944af | 2004 | buf[sizeof(buf) - 1] = 0; |
249771b8 AE |
2005 | options = strchr(str, ','); |
2006 | if (options) | |
2ea1c539 JB |
2007 | *(options++) = 0; |
2008 | #ifdef __sparc__ | |
2009 | if (!strcmp(str, "ttya")) | |
eaa944af | 2010 | strcpy(buf, "ttyS0"); |
2ea1c539 | 2011 | if (!strcmp(str, "ttyb")) |
eaa944af | 2012 | strcpy(buf, "ttyS1"); |
2ea1c539 | 2013 | #endif |
eaa944af | 2014 | for (s = buf; *s; s++) |
249771b8 | 2015 | if (isdigit(*s) || *s == ',') |
2ea1c539 JB |
2016 | break; |
2017 | idx = simple_strtoul(s, NULL, 10); | |
2018 | *s = 0; | |
2019 | ||
f7511d5f | 2020 | __add_preferred_console(buf, idx, options, brl_options); |
9e124fe1 | 2021 | console_set_on_cmdline = 1; |
2ea1c539 JB |
2022 | return 1; |
2023 | } | |
2024 | __setup("console=", console_setup); | |
2025 | ||
3c0547ba MM |
2026 | /** |
2027 | * add_preferred_console - add a device to the list of preferred consoles. | |
ddad86c2 MW |
2028 | * @name: device name |
2029 | * @idx: device index | |
2030 | * @options: options for this console | |
3c0547ba MM |
2031 | * |
2032 | * The last preferred console added will be used for kernel messages | |
2033 | * and stdin/out/err for init. Normally this is used by console_setup | |
2034 | * above to handle user-supplied console arguments; however it can also | |
2035 | * be used by arch-specific code either to override the user or more | |
2036 | * commonly to provide a default console (ie from PROM variables) when | |
2037 | * the user has not supplied one. | |
2038 | */ | |
fb445ee5 | 2039 | int add_preferred_console(char *name, int idx, char *options) |
3c0547ba | 2040 | { |
f7511d5f | 2041 | return __add_preferred_console(name, idx, options, NULL); |
3c0547ba MM |
2042 | } |
2043 | ||
d25d9fec | 2044 | bool console_suspend_enabled = true; |
8f4ce8c3 AS |
2045 | EXPORT_SYMBOL(console_suspend_enabled); |
2046 | ||
2047 | static int __init console_suspend_disable(char *str) | |
2048 | { | |
d25d9fec | 2049 | console_suspend_enabled = false; |
8f4ce8c3 AS |
2050 | return 1; |
2051 | } | |
2052 | __setup("no_console_suspend", console_suspend_disable); | |
134620f7 YZ |
2053 | module_param_named(console_suspend, console_suspend_enabled, |
2054 | bool, S_IRUGO | S_IWUSR); | |
2055 | MODULE_PARM_DESC(console_suspend, "suspend console during suspend" | |
2056 | " and hibernate operations"); | |
8f4ce8c3 | 2057 | |
557240b4 LT |
2058 | /** |
2059 | * suspend_console - suspend the console subsystem | |
2060 | * | |
2061 | * This disables printk() while we go into suspend states | |
2062 | */ | |
2063 | void suspend_console(void) | |
2064 | { | |
8f4ce8c3 AS |
2065 | if (!console_suspend_enabled) |
2066 | return; | |
0d63081d | 2067 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
ac751efa | 2068 | console_lock(); |
557240b4 | 2069 | console_suspended = 1; |
bd8d7cf5 | 2070 | up_console_sem(); |
557240b4 LT |
2071 | } |
2072 | ||
2073 | void resume_console(void) | |
2074 | { | |
8f4ce8c3 AS |
2075 | if (!console_suspend_enabled) |
2076 | return; | |
bd8d7cf5 | 2077 | down_console_sem(); |
557240b4 | 2078 | console_suspended = 0; |
ac751efa | 2079 | console_unlock(); |
557240b4 LT |
2080 | } |
2081 | ||
034260d6 KC |
2082 | /** |
2083 | * console_cpu_notify - print deferred console messages after CPU hotplug | |
2084 | * @self: notifier struct | |
2085 | * @action: CPU hotplug event | |
2086 | * @hcpu: unused | |
2087 | * | |
2088 | * If printk() is called from a CPU that is not online yet, the messages | |
2089 | * will be spooled but will not show up on the console. This function is | |
2090 | * called when a new CPU comes online (or fails to come up), and ensures | |
2091 | * that any such output gets printed. | |
2092 | */ | |
0db0628d | 2093 | static int console_cpu_notify(struct notifier_block *self, |
034260d6 KC |
2094 | unsigned long action, void *hcpu) |
2095 | { | |
2096 | switch (action) { | |
2097 | case CPU_ONLINE: | |
2098 | case CPU_DEAD: | |
034260d6 KC |
2099 | case CPU_DOWN_FAILED: |
2100 | case CPU_UP_CANCELED: | |
ac751efa TH |
2101 | console_lock(); |
2102 | console_unlock(); | |
034260d6 KC |
2103 | } |
2104 | return NOTIFY_OK; | |
2105 | } | |
2106 | ||
1da177e4 | 2107 | /** |
ac751efa | 2108 | * console_lock - lock the console system for exclusive use. |
1da177e4 | 2109 | * |
ac751efa | 2110 | * Acquires a lock which guarantees that the caller has |
1da177e4 LT |
2111 | * exclusive access to the console system and the console_drivers list. |
2112 | * | |
2113 | * Can sleep, returns nothing. | |
2114 | */ | |
ac751efa | 2115 | void console_lock(void) |
1da177e4 | 2116 | { |
6b898c07 DV |
2117 | might_sleep(); |
2118 | ||
bd8d7cf5 | 2119 | down_console_sem(); |
403f3075 AH |
2120 | if (console_suspended) |
2121 | return; | |
1da177e4 LT |
2122 | console_locked = 1; |
2123 | console_may_schedule = 1; | |
2124 | } | |
ac751efa | 2125 | EXPORT_SYMBOL(console_lock); |
1da177e4 | 2126 | |
ac751efa TH |
2127 | /** |
2128 | * console_trylock - try to lock the console system for exclusive use. | |
2129 | * | |
0b90fec3 AE |
2130 | * Try to acquire a lock which guarantees that the caller has exclusive |
2131 | * access to the console system and the console_drivers list. | |
ac751efa TH |
2132 | * |
2133 | * returns 1 on success, and 0 on failure to acquire the lock. | |
2134 | */ | |
2135 | int console_trylock(void) | |
1da177e4 | 2136 | { |
bd8d7cf5 | 2137 | if (down_trylock_console_sem()) |
ac751efa | 2138 | return 0; |
403f3075 | 2139 | if (console_suspended) { |
bd8d7cf5 | 2140 | up_console_sem(); |
ac751efa | 2141 | return 0; |
403f3075 | 2142 | } |
1da177e4 LT |
2143 | console_locked = 1; |
2144 | console_may_schedule = 0; | |
ac751efa | 2145 | return 1; |
1da177e4 | 2146 | } |
ac751efa | 2147 | EXPORT_SYMBOL(console_trylock); |
1da177e4 LT |
2148 | |
2149 | int is_console_locked(void) | |
2150 | { | |
2151 | return console_locked; | |
2152 | } | |
1da177e4 | 2153 | |
eab07260 KS |
2154 | static void console_cont_flush(char *text, size_t size) |
2155 | { | |
2156 | unsigned long flags; | |
2157 | size_t len; | |
2158 | ||
2159 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2160 | ||
2161 | if (!cont.len) | |
2162 | goto out; | |
2163 | ||
2164 | /* | |
2165 | * We still queue earlier records, likely because the console was | |
2166 | * busy. The earlier ones need to be printed before this one, we | |
2167 | * did not flush any fragment so far, so just let it queue up. | |
2168 | */ | |
2169 | if (console_seq < log_next_seq && !cont.cons) | |
2170 | goto out; | |
2171 | ||
2172 | len = cont_print_text(text, size); | |
2173 | raw_spin_unlock(&logbuf_lock); | |
2174 | stop_critical_timings(); | |
2175 | call_console_drivers(cont.level, text, len); | |
2176 | start_critical_timings(); | |
2177 | local_irq_restore(flags); | |
2178 | return; | |
2179 | out: | |
2180 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2181 | } | |
7ff9554b | 2182 | |
1da177e4 | 2183 | /** |
ac751efa | 2184 | * console_unlock - unlock the console system |
1da177e4 | 2185 | * |
ac751efa | 2186 | * Releases the console_lock which the caller holds on the console system |
1da177e4 LT |
2187 | * and the console driver list. |
2188 | * | |
ac751efa TH |
2189 | * While the console_lock was held, console output may have been buffered |
2190 | * by printk(). If this is the case, console_unlock(); emits | |
2191 | * the output prior to releasing the lock. | |
1da177e4 | 2192 | * |
7f3a781d | 2193 | * If there is output waiting, we wake /dev/kmsg and syslog() users. |
1da177e4 | 2194 | * |
ac751efa | 2195 | * console_unlock(); may be called from any context. |
1da177e4 | 2196 | */ |
ac751efa | 2197 | void console_unlock(void) |
1da177e4 | 2198 | { |
70498253 | 2199 | static char text[LOG_LINE_MAX + PREFIX_MAX]; |
7ff9554b | 2200 | static u64 seen_seq; |
1da177e4 | 2201 | unsigned long flags; |
7ff9554b KS |
2202 | bool wake_klogd = false; |
2203 | bool retry; | |
1da177e4 | 2204 | |
557240b4 | 2205 | if (console_suspended) { |
bd8d7cf5 | 2206 | up_console_sem(); |
557240b4 LT |
2207 | return; |
2208 | } | |
78944e54 AD |
2209 | |
2210 | console_may_schedule = 0; | |
2211 | ||
084681d1 | 2212 | /* flush buffered message fragment immediately to console */ |
eab07260 | 2213 | console_cont_flush(text, sizeof(text)); |
4f2a8d3c | 2214 | again: |
7ff9554b | 2215 | for (;;) { |
62e32ac3 | 2216 | struct printk_log *msg; |
3ce9a7c0 | 2217 | size_t len; |
7ff9554b KS |
2218 | int level; |
2219 | ||
07354eb1 | 2220 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2221 | if (seen_seq != log_next_seq) { |
2222 | wake_klogd = true; | |
2223 | seen_seq = log_next_seq; | |
2224 | } | |
2225 | ||
2226 | if (console_seq < log_first_seq) { | |
84b5ec8a WD |
2227 | len = sprintf(text, "** %u printk messages dropped ** ", |
2228 | (unsigned)(log_first_seq - console_seq)); | |
2229 | ||
7ff9554b KS |
2230 | /* messages are gone, move to first one */ |
2231 | console_seq = log_first_seq; | |
2232 | console_idx = log_first_idx; | |
5becfb1d | 2233 | console_prev = 0; |
84b5ec8a WD |
2234 | } else { |
2235 | len = 0; | |
7ff9554b | 2236 | } |
084681d1 | 2237 | skip: |
7ff9554b KS |
2238 | if (console_seq == log_next_seq) |
2239 | break; | |
2240 | ||
2241 | msg = log_from_idx(console_idx); | |
084681d1 KS |
2242 | if (msg->flags & LOG_NOCONS) { |
2243 | /* | |
2244 | * Skip record we have buffered and already printed | |
2245 | * directly to the console when we received it. | |
2246 | */ | |
2247 | console_idx = log_next(console_idx); | |
2248 | console_seq++; | |
68b6507d KS |
2249 | /* |
2250 | * We will get here again when we register a new | |
2251 | * CON_PRINTBUFFER console. Clear the flag so we | |
2252 | * will properly dump everything later. | |
2253 | */ | |
2254 | msg->flags &= ~LOG_NOCONS; | |
eab07260 | 2255 | console_prev = msg->flags; |
084681d1 KS |
2256 | goto skip; |
2257 | } | |
649e6ee3 | 2258 | |
084681d1 | 2259 | level = msg->level; |
84b5ec8a WD |
2260 | len += msg_print_text(msg, console_prev, false, |
2261 | text + len, sizeof(text) - len); | |
7ff9554b KS |
2262 | console_idx = log_next(console_idx); |
2263 | console_seq++; | |
5becfb1d | 2264 | console_prev = msg->flags; |
07354eb1 | 2265 | raw_spin_unlock(&logbuf_lock); |
7ff9554b | 2266 | |
81d68a96 | 2267 | stop_critical_timings(); /* don't trace print latency */ |
7ff9554b | 2268 | call_console_drivers(level, text, len); |
81d68a96 | 2269 | start_critical_timings(); |
1da177e4 LT |
2270 | local_irq_restore(flags); |
2271 | } | |
2272 | console_locked = 0; | |
fe3d8ad3 FT |
2273 | |
2274 | /* Release the exclusive_console once it is used */ | |
2275 | if (unlikely(exclusive_console)) | |
2276 | exclusive_console = NULL; | |
2277 | ||
07354eb1 | 2278 | raw_spin_unlock(&logbuf_lock); |
4f2a8d3c | 2279 | |
bd8d7cf5 | 2280 | up_console_sem(); |
4f2a8d3c PZ |
2281 | |
2282 | /* | |
2283 | * Someone could have filled up the buffer again, so re-check if there's | |
2284 | * something to flush. In case we cannot trylock the console_sem again, | |
2285 | * there's a new owner and the console_unlock() from them will do the | |
2286 | * flush, no worries. | |
2287 | */ | |
07354eb1 | 2288 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 2289 | retry = console_seq != log_next_seq; |
09dc3cf9 PZ |
2290 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
2291 | ||
4f2a8d3c PZ |
2292 | if (retry && console_trylock()) |
2293 | goto again; | |
2294 | ||
e3e8a75d KK |
2295 | if (wake_klogd) |
2296 | wake_up_klogd(); | |
1da177e4 | 2297 | } |
ac751efa | 2298 | EXPORT_SYMBOL(console_unlock); |
1da177e4 | 2299 | |
ddad86c2 MW |
2300 | /** |
2301 | * console_conditional_schedule - yield the CPU if required | |
1da177e4 LT |
2302 | * |
2303 | * If the console code is currently allowed to sleep, and | |
2304 | * if this CPU should yield the CPU to another task, do | |
2305 | * so here. | |
2306 | * | |
ac751efa | 2307 | * Must be called within console_lock();. |
1da177e4 LT |
2308 | */ |
2309 | void __sched console_conditional_schedule(void) | |
2310 | { | |
2311 | if (console_may_schedule) | |
2312 | cond_resched(); | |
2313 | } | |
2314 | EXPORT_SYMBOL(console_conditional_schedule); | |
2315 | ||
1da177e4 LT |
2316 | void console_unblank(void) |
2317 | { | |
2318 | struct console *c; | |
2319 | ||
2320 | /* | |
2321 | * console_unblank can no longer be called in interrupt context unless | |
2322 | * oops_in_progress is set to 1.. | |
2323 | */ | |
2324 | if (oops_in_progress) { | |
bd8d7cf5 | 2325 | if (down_trylock_console_sem() != 0) |
1da177e4 LT |
2326 | return; |
2327 | } else | |
ac751efa | 2328 | console_lock(); |
1da177e4 LT |
2329 | |
2330 | console_locked = 1; | |
2331 | console_may_schedule = 0; | |
4d091611 | 2332 | for_each_console(c) |
1da177e4 LT |
2333 | if ((c->flags & CON_ENABLED) && c->unblank) |
2334 | c->unblank(); | |
ac751efa | 2335 | console_unlock(); |
1da177e4 | 2336 | } |
1da177e4 LT |
2337 | |
2338 | /* | |
2339 | * Return the console tty driver structure and its associated index | |
2340 | */ | |
2341 | struct tty_driver *console_device(int *index) | |
2342 | { | |
2343 | struct console *c; | |
2344 | struct tty_driver *driver = NULL; | |
2345 | ||
ac751efa | 2346 | console_lock(); |
4d091611 | 2347 | for_each_console(c) { |
1da177e4 LT |
2348 | if (!c->device) |
2349 | continue; | |
2350 | driver = c->device(c, index); | |
2351 | if (driver) | |
2352 | break; | |
2353 | } | |
ac751efa | 2354 | console_unlock(); |
1da177e4 LT |
2355 | return driver; |
2356 | } | |
2357 | ||
2358 | /* | |
2359 | * Prevent further output on the passed console device so that (for example) | |
2360 | * serial drivers can disable console output before suspending a port, and can | |
2361 | * re-enable output afterwards. | |
2362 | */ | |
2363 | void console_stop(struct console *console) | |
2364 | { | |
ac751efa | 2365 | console_lock(); |
1da177e4 | 2366 | console->flags &= ~CON_ENABLED; |
ac751efa | 2367 | console_unlock(); |
1da177e4 LT |
2368 | } |
2369 | EXPORT_SYMBOL(console_stop); | |
2370 | ||
2371 | void console_start(struct console *console) | |
2372 | { | |
ac751efa | 2373 | console_lock(); |
1da177e4 | 2374 | console->flags |= CON_ENABLED; |
ac751efa | 2375 | console_unlock(); |
1da177e4 LT |
2376 | } |
2377 | EXPORT_SYMBOL(console_start); | |
2378 | ||
7bf69395 FDN |
2379 | static int __read_mostly keep_bootcon; |
2380 | ||
2381 | static int __init keep_bootcon_setup(char *str) | |
2382 | { | |
2383 | keep_bootcon = 1; | |
27083bac | 2384 | pr_info("debug: skip boot console de-registration.\n"); |
7bf69395 FDN |
2385 | |
2386 | return 0; | |
2387 | } | |
2388 | ||
2389 | early_param("keep_bootcon", keep_bootcon_setup); | |
2390 | ||
1da177e4 LT |
2391 | /* |
2392 | * The console driver calls this routine during kernel initialization | |
2393 | * to register the console printing procedure with printk() and to | |
2394 | * print any messages that were printed by the kernel before the | |
2395 | * console driver was initialized. | |
4d091611 RG |
2396 | * |
2397 | * This can happen pretty early during the boot process (because of | |
2398 | * early_printk) - sometimes before setup_arch() completes - be careful | |
2399 | * of what kernel features are used - they may not be initialised yet. | |
2400 | * | |
2401 | * There are two types of consoles - bootconsoles (early_printk) and | |
2402 | * "real" consoles (everything which is not a bootconsole) which are | |
2403 | * handled differently. | |
2404 | * - Any number of bootconsoles can be registered at any time. | |
2405 | * - As soon as a "real" console is registered, all bootconsoles | |
2406 | * will be unregistered automatically. | |
2407 | * - Once a "real" console is registered, any attempt to register a | |
2408 | * bootconsoles will be rejected | |
1da177e4 | 2409 | */ |
4d091611 | 2410 | void register_console(struct console *newcon) |
1da177e4 | 2411 | { |
40dc5651 | 2412 | int i; |
1da177e4 | 2413 | unsigned long flags; |
4d091611 | 2414 | struct console *bcon = NULL; |
23475408 | 2415 | struct console_cmdline *c; |
1da177e4 | 2416 | |
16cf48a6 AB |
2417 | if (console_drivers) |
2418 | for_each_console(bcon) | |
2419 | if (WARN(bcon == newcon, | |
2420 | "console '%s%d' already registered\n", | |
2421 | bcon->name, bcon->index)) | |
2422 | return; | |
2423 | ||
4d091611 RG |
2424 | /* |
2425 | * before we register a new CON_BOOT console, make sure we don't | |
2426 | * already have a valid console | |
2427 | */ | |
2428 | if (console_drivers && newcon->flags & CON_BOOT) { | |
2429 | /* find the last or real console */ | |
2430 | for_each_console(bcon) { | |
2431 | if (!(bcon->flags & CON_BOOT)) { | |
27083bac | 2432 | pr_info("Too late to register bootconsole %s%d\n", |
4d091611 RG |
2433 | newcon->name, newcon->index); |
2434 | return; | |
2435 | } | |
2436 | } | |
69331af7 GH |
2437 | } |
2438 | ||
4d091611 RG |
2439 | if (console_drivers && console_drivers->flags & CON_BOOT) |
2440 | bcon = console_drivers; | |
2441 | ||
2442 | if (preferred_console < 0 || bcon || !console_drivers) | |
1da177e4 LT |
2443 | preferred_console = selected_console; |
2444 | ||
2445 | /* | |
2446 | * See if we want to use this console driver. If we | |
2447 | * didn't select a console we take the first one | |
2448 | * that registers here. | |
2449 | */ | |
2450 | if (preferred_console < 0) { | |
4d091611 RG |
2451 | if (newcon->index < 0) |
2452 | newcon->index = 0; | |
2453 | if (newcon->setup == NULL || | |
2454 | newcon->setup(newcon, NULL) == 0) { | |
2455 | newcon->flags |= CON_ENABLED; | |
2456 | if (newcon->device) { | |
2457 | newcon->flags |= CON_CONSDEV; | |
cd3a1b85 JK |
2458 | preferred_console = 0; |
2459 | } | |
1da177e4 LT |
2460 | } |
2461 | } | |
2462 | ||
2463 | /* | |
2464 | * See if this console matches one we selected on | |
2465 | * the command line. | |
2466 | */ | |
23475408 JP |
2467 | for (i = 0, c = console_cmdline; |
2468 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
2469 | i++, c++) { | |
c7cef0a8 PH |
2470 | if (!newcon->match || |
2471 | newcon->match(newcon, c->name, c->index, c->options) != 0) { | |
2472 | /* default matching */ | |
2473 | BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name)); | |
2474 | if (strcmp(c->name, newcon->name) != 0) | |
2475 | continue; | |
2476 | if (newcon->index >= 0 && | |
2477 | newcon->index != c->index) | |
2478 | continue; | |
2479 | if (newcon->index < 0) | |
2480 | newcon->index = c->index; | |
bbeddf52 | 2481 | |
c7cef0a8 PH |
2482 | if (_braille_register_console(newcon, c)) |
2483 | return; | |
2484 | ||
2485 | if (newcon->setup && | |
2486 | newcon->setup(newcon, c->options) != 0) | |
2487 | break; | |
2488 | } | |
bbeddf52 | 2489 | |
4d091611 | 2490 | newcon->flags |= CON_ENABLED; |
ab4af03a | 2491 | if (i == selected_console) { |
4d091611 | 2492 | newcon->flags |= CON_CONSDEV; |
ab4af03a GE |
2493 | preferred_console = selected_console; |
2494 | } | |
1da177e4 LT |
2495 | break; |
2496 | } | |
2497 | ||
4d091611 | 2498 | if (!(newcon->flags & CON_ENABLED)) |
1da177e4 LT |
2499 | return; |
2500 | ||
8259cf43 RG |
2501 | /* |
2502 | * If we have a bootconsole, and are switching to a real console, | |
2503 | * don't print everything out again, since when the boot console, and | |
2504 | * the real console are the same physical device, it's annoying to | |
2505 | * see the beginning boot messages twice | |
2506 | */ | |
2507 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) | |
4d091611 | 2508 | newcon->flags &= ~CON_PRINTBUFFER; |
1da177e4 LT |
2509 | |
2510 | /* | |
2511 | * Put this console in the list - keep the | |
2512 | * preferred driver at the head of the list. | |
2513 | */ | |
ac751efa | 2514 | console_lock(); |
4d091611 RG |
2515 | if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
2516 | newcon->next = console_drivers; | |
2517 | console_drivers = newcon; | |
2518 | if (newcon->next) | |
2519 | newcon->next->flags &= ~CON_CONSDEV; | |
1da177e4 | 2520 | } else { |
4d091611 RG |
2521 | newcon->next = console_drivers->next; |
2522 | console_drivers->next = newcon; | |
1da177e4 | 2523 | } |
4d091611 | 2524 | if (newcon->flags & CON_PRINTBUFFER) { |
1da177e4 | 2525 | /* |
ac751efa | 2526 | * console_unlock(); will print out the buffered messages |
1da177e4 LT |
2527 | * for us. |
2528 | */ | |
07354eb1 | 2529 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2530 | console_seq = syslog_seq; |
2531 | console_idx = syslog_idx; | |
5becfb1d | 2532 | console_prev = syslog_prev; |
07354eb1 | 2533 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
fe3d8ad3 FT |
2534 | /* |
2535 | * We're about to replay the log buffer. Only do this to the | |
2536 | * just-registered console to avoid excessive message spam to | |
2537 | * the already-registered consoles. | |
2538 | */ | |
2539 | exclusive_console = newcon; | |
1da177e4 | 2540 | } |
ac751efa | 2541 | console_unlock(); |
fbc92a34 | 2542 | console_sysfs_notify(); |
8259cf43 RG |
2543 | |
2544 | /* | |
2545 | * By unregistering the bootconsoles after we enable the real console | |
2546 | * we get the "console xxx enabled" message on all the consoles - | |
2547 | * boot consoles, real consoles, etc - this is to ensure that end | |
2548 | * users know there might be something in the kernel's log buffer that | |
2549 | * went to the bootconsole (that they do not see on the real console) | |
2550 | */ | |
27083bac | 2551 | pr_info("%sconsole [%s%d] enabled\n", |
6b802394 KC |
2552 | (newcon->flags & CON_BOOT) ? "boot" : "" , |
2553 | newcon->name, newcon->index); | |
7bf69395 FDN |
2554 | if (bcon && |
2555 | ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && | |
2556 | !keep_bootcon) { | |
6b802394 KC |
2557 | /* We need to iterate through all boot consoles, to make |
2558 | * sure we print everything out, before we unregister them. | |
8259cf43 | 2559 | */ |
8259cf43 RG |
2560 | for_each_console(bcon) |
2561 | if (bcon->flags & CON_BOOT) | |
2562 | unregister_console(bcon); | |
8259cf43 | 2563 | } |
1da177e4 LT |
2564 | } |
2565 | EXPORT_SYMBOL(register_console); | |
2566 | ||
40dc5651 | 2567 | int unregister_console(struct console *console) |
1da177e4 | 2568 | { |
40dc5651 | 2569 | struct console *a, *b; |
bbeddf52 | 2570 | int res; |
1da177e4 | 2571 | |
27083bac | 2572 | pr_info("%sconsole [%s%d] disabled\n", |
6b802394 KC |
2573 | (console->flags & CON_BOOT) ? "boot" : "" , |
2574 | console->name, console->index); | |
2575 | ||
bbeddf52 JP |
2576 | res = _braille_unregister_console(console); |
2577 | if (res) | |
2578 | return res; | |
f7511d5f | 2579 | |
bbeddf52 | 2580 | res = 1; |
ac751efa | 2581 | console_lock(); |
1da177e4 LT |
2582 | if (console_drivers == console) { |
2583 | console_drivers=console->next; | |
2584 | res = 0; | |
e9b15b54 | 2585 | } else if (console_drivers) { |
1da177e4 LT |
2586 | for (a=console_drivers->next, b=console_drivers ; |
2587 | a; b=a, a=b->next) { | |
2588 | if (a == console) { | |
2589 | b->next = a->next; | |
2590 | res = 0; | |
2591 | break; | |
40dc5651 | 2592 | } |
1da177e4 LT |
2593 | } |
2594 | } | |
40dc5651 | 2595 | |
69331af7 | 2596 | /* |
ab4af03a GE |
2597 | * If this isn't the last console and it has CON_CONSDEV set, we |
2598 | * need to set it on the next preferred console. | |
1da177e4 | 2599 | */ |
69331af7 | 2600 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
ab4af03a | 2601 | console_drivers->flags |= CON_CONSDEV; |
1da177e4 | 2602 | |
7fa21dd8 | 2603 | console->flags &= ~CON_ENABLED; |
ac751efa | 2604 | console_unlock(); |
fbc92a34 | 2605 | console_sysfs_notify(); |
1da177e4 LT |
2606 | return res; |
2607 | } | |
2608 | EXPORT_SYMBOL(unregister_console); | |
d59745ce | 2609 | |
034260d6 | 2610 | static int __init printk_late_init(void) |
0c5564bd | 2611 | { |
4d091611 RG |
2612 | struct console *con; |
2613 | ||
2614 | for_each_console(con) { | |
4c30c6f5 | 2615 | if (!keep_bootcon && con->flags & CON_BOOT) { |
42c2c8c8 | 2616 | unregister_console(con); |
cb00e99c | 2617 | } |
0c5564bd | 2618 | } |
034260d6 | 2619 | hotcpu_notifier(console_cpu_notify, 0); |
0c5564bd RG |
2620 | return 0; |
2621 | } | |
034260d6 | 2622 | late_initcall(printk_late_init); |
0c5564bd | 2623 | |
7ef3d2fd | 2624 | #if defined CONFIG_PRINTK |
dc72c32e FW |
2625 | /* |
2626 | * Delayed printk version, for scheduler-internal messages: | |
2627 | */ | |
dc72c32e | 2628 | #define PRINTK_PENDING_WAKEUP 0x01 |
458df9fd | 2629 | #define PRINTK_PENDING_OUTPUT 0x02 |
dc72c32e FW |
2630 | |
2631 | static DEFINE_PER_CPU(int, printk_pending); | |
dc72c32e FW |
2632 | |
2633 | static void wake_up_klogd_work_func(struct irq_work *irq_work) | |
2634 | { | |
2635 | int pending = __this_cpu_xchg(printk_pending, 0); | |
2636 | ||
458df9fd SR |
2637 | if (pending & PRINTK_PENDING_OUTPUT) { |
2638 | /* If trylock fails, someone else is doing the printing */ | |
2639 | if (console_trylock()) | |
2640 | console_unlock(); | |
dc72c32e FW |
2641 | } |
2642 | ||
2643 | if (pending & PRINTK_PENDING_WAKEUP) | |
2644 | wake_up_interruptible(&log_wait); | |
2645 | } | |
2646 | ||
2647 | static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = { | |
2648 | .func = wake_up_klogd_work_func, | |
2649 | .flags = IRQ_WORK_LAZY, | |
2650 | }; | |
2651 | ||
2652 | void wake_up_klogd(void) | |
2653 | { | |
2654 | preempt_disable(); | |
2655 | if (waitqueue_active(&log_wait)) { | |
2656 | this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); | |
bb964a92 | 2657 | irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); |
dc72c32e FW |
2658 | } |
2659 | preempt_enable(); | |
2660 | } | |
717115e1 | 2661 | |
aac74dc4 | 2662 | int printk_deferred(const char *fmt, ...) |
600e1458 | 2663 | { |
600e1458 | 2664 | va_list args; |
600e1458 PZ |
2665 | int r; |
2666 | ||
81954606 | 2667 | preempt_disable(); |
600e1458 | 2668 | va_start(args, fmt); |
a39d4a85 | 2669 | r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args); |
600e1458 PZ |
2670 | va_end(args); |
2671 | ||
458df9fd | 2672 | __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT); |
bb964a92 | 2673 | irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); |
81954606 | 2674 | preempt_enable(); |
600e1458 PZ |
2675 | |
2676 | return r; | |
2677 | } | |
2678 | ||
1da177e4 LT |
2679 | /* |
2680 | * printk rate limiting, lifted from the networking subsystem. | |
2681 | * | |
641de9d8 UKK |
2682 | * This enforces a rate limit: not more than 10 kernel messages |
2683 | * every 5s to make a denial-of-service attack impossible. | |
1da177e4 | 2684 | */ |
641de9d8 UKK |
2685 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
2686 | ||
5c828713 | 2687 | int __printk_ratelimit(const char *func) |
1da177e4 | 2688 | { |
5c828713 | 2689 | return ___ratelimit(&printk_ratelimit_state, func); |
1da177e4 | 2690 | } |
5c828713 | 2691 | EXPORT_SYMBOL(__printk_ratelimit); |
f46c4833 AM |
2692 | |
2693 | /** | |
2694 | * printk_timed_ratelimit - caller-controlled printk ratelimiting | |
2695 | * @caller_jiffies: pointer to caller's state | |
2696 | * @interval_msecs: minimum interval between prints | |
2697 | * | |
2698 | * printk_timed_ratelimit() returns true if more than @interval_msecs | |
2699 | * milliseconds have elapsed since the last time printk_timed_ratelimit() | |
2700 | * returned true. | |
2701 | */ | |
2702 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, | |
2703 | unsigned int interval_msecs) | |
2704 | { | |
249771b8 AE |
2705 | unsigned long elapsed = jiffies - *caller_jiffies; |
2706 | ||
2707 | if (*caller_jiffies && elapsed <= msecs_to_jiffies(interval_msecs)) | |
2708 | return false; | |
2709 | ||
2710 | *caller_jiffies = jiffies; | |
2711 | return true; | |
f46c4833 AM |
2712 | } |
2713 | EXPORT_SYMBOL(printk_timed_ratelimit); | |
456b565c SK |
2714 | |
2715 | static DEFINE_SPINLOCK(dump_list_lock); | |
2716 | static LIST_HEAD(dump_list); | |
2717 | ||
2718 | /** | |
2719 | * kmsg_dump_register - register a kernel log dumper. | |
6485536b | 2720 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2721 | * |
2722 | * Adds a kernel log dumper to the system. The dump callback in the | |
2723 | * structure will be called when the kernel oopses or panics and must be | |
2724 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. | |
2725 | */ | |
2726 | int kmsg_dump_register(struct kmsg_dumper *dumper) | |
2727 | { | |
2728 | unsigned long flags; | |
2729 | int err = -EBUSY; | |
2730 | ||
2731 | /* The dump callback needs to be set */ | |
2732 | if (!dumper->dump) | |
2733 | return -EINVAL; | |
2734 | ||
2735 | spin_lock_irqsave(&dump_list_lock, flags); | |
2736 | /* Don't allow registering multiple times */ | |
2737 | if (!dumper->registered) { | |
2738 | dumper->registered = 1; | |
fb842b00 | 2739 | list_add_tail_rcu(&dumper->list, &dump_list); |
456b565c SK |
2740 | err = 0; |
2741 | } | |
2742 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
2743 | ||
2744 | return err; | |
2745 | } | |
2746 | EXPORT_SYMBOL_GPL(kmsg_dump_register); | |
2747 | ||
2748 | /** | |
2749 | * kmsg_dump_unregister - unregister a kmsg dumper. | |
6485536b | 2750 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2751 | * |
2752 | * Removes a dump device from the system. Returns zero on success and | |
2753 | * %-EINVAL otherwise. | |
2754 | */ | |
2755 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) | |
2756 | { | |
2757 | unsigned long flags; | |
2758 | int err = -EINVAL; | |
2759 | ||
2760 | spin_lock_irqsave(&dump_list_lock, flags); | |
2761 | if (dumper->registered) { | |
2762 | dumper->registered = 0; | |
fb842b00 | 2763 | list_del_rcu(&dumper->list); |
456b565c SK |
2764 | err = 0; |
2765 | } | |
2766 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
fb842b00 | 2767 | synchronize_rcu(); |
456b565c SK |
2768 | |
2769 | return err; | |
2770 | } | |
2771 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); | |
2772 | ||
7ff9554b KS |
2773 | static bool always_kmsg_dump; |
2774 | module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); | |
2775 | ||
456b565c SK |
2776 | /** |
2777 | * kmsg_dump - dump kernel log to kernel message dumpers. | |
2778 | * @reason: the reason (oops, panic etc) for dumping | |
2779 | * | |
e2ae715d KS |
2780 | * Call each of the registered dumper's dump() callback, which can |
2781 | * retrieve the kmsg records with kmsg_dump_get_line() or | |
2782 | * kmsg_dump_get_buffer(). | |
456b565c SK |
2783 | */ |
2784 | void kmsg_dump(enum kmsg_dump_reason reason) | |
2785 | { | |
456b565c | 2786 | struct kmsg_dumper *dumper; |
456b565c SK |
2787 | unsigned long flags; |
2788 | ||
c22ab332 MG |
2789 | if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) |
2790 | return; | |
2791 | ||
e2ae715d KS |
2792 | rcu_read_lock(); |
2793 | list_for_each_entry_rcu(dumper, &dump_list, list) { | |
2794 | if (dumper->max_reason && reason > dumper->max_reason) | |
2795 | continue; | |
2796 | ||
2797 | /* initialize iterator with data about the stored records */ | |
2798 | dumper->active = true; | |
2799 | ||
2800 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2801 | dumper->cur_seq = clear_seq; | |
2802 | dumper->cur_idx = clear_idx; | |
2803 | dumper->next_seq = log_next_seq; | |
2804 | dumper->next_idx = log_next_idx; | |
2805 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2806 | ||
2807 | /* invoke dumper which will iterate over records */ | |
2808 | dumper->dump(dumper, reason); | |
2809 | ||
2810 | /* reset iterator */ | |
2811 | dumper->active = false; | |
2812 | } | |
2813 | rcu_read_unlock(); | |
2814 | } | |
2815 | ||
2816 | /** | |
533827c9 | 2817 | * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) |
e2ae715d KS |
2818 | * @dumper: registered kmsg dumper |
2819 | * @syslog: include the "<4>" prefixes | |
2820 | * @line: buffer to copy the line to | |
2821 | * @size: maximum size of the buffer | |
2822 | * @len: length of line placed into buffer | |
2823 | * | |
2824 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2825 | * record, and copy one record into the provided buffer. | |
2826 | * | |
2827 | * Consecutive calls will return the next available record moving | |
2828 | * towards the end of the buffer with the youngest messages. | |
2829 | * | |
2830 | * A return value of FALSE indicates that there are no more records to | |
2831 | * read. | |
533827c9 AV |
2832 | * |
2833 | * The function is similar to kmsg_dump_get_line(), but grabs no locks. | |
e2ae715d | 2834 | */ |
533827c9 AV |
2835 | bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, |
2836 | char *line, size_t size, size_t *len) | |
e2ae715d | 2837 | { |
62e32ac3 | 2838 | struct printk_log *msg; |
e2ae715d KS |
2839 | size_t l = 0; |
2840 | bool ret = false; | |
2841 | ||
2842 | if (!dumper->active) | |
2843 | goto out; | |
7ff9554b | 2844 | |
e2ae715d KS |
2845 | if (dumper->cur_seq < log_first_seq) { |
2846 | /* messages are gone, move to first available one */ | |
2847 | dumper->cur_seq = log_first_seq; | |
2848 | dumper->cur_idx = log_first_idx; | |
2849 | } | |
456b565c | 2850 | |
e2ae715d | 2851 | /* last entry */ |
533827c9 | 2852 | if (dumper->cur_seq >= log_next_seq) |
e2ae715d | 2853 | goto out; |
456b565c | 2854 | |
e2ae715d | 2855 | msg = log_from_idx(dumper->cur_idx); |
5becfb1d | 2856 | l = msg_print_text(msg, 0, syslog, line, size); |
e2ae715d KS |
2857 | |
2858 | dumper->cur_idx = log_next(dumper->cur_idx); | |
2859 | dumper->cur_seq++; | |
2860 | ret = true; | |
e2ae715d KS |
2861 | out: |
2862 | if (len) | |
2863 | *len = l; | |
2864 | return ret; | |
2865 | } | |
533827c9 AV |
2866 | |
2867 | /** | |
2868 | * kmsg_dump_get_line - retrieve one kmsg log line | |
2869 | * @dumper: registered kmsg dumper | |
2870 | * @syslog: include the "<4>" prefixes | |
2871 | * @line: buffer to copy the line to | |
2872 | * @size: maximum size of the buffer | |
2873 | * @len: length of line placed into buffer | |
2874 | * | |
2875 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2876 | * record, and copy one record into the provided buffer. | |
2877 | * | |
2878 | * Consecutive calls will return the next available record moving | |
2879 | * towards the end of the buffer with the youngest messages. | |
2880 | * | |
2881 | * A return value of FALSE indicates that there are no more records to | |
2882 | * read. | |
2883 | */ | |
2884 | bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, | |
2885 | char *line, size_t size, size_t *len) | |
2886 | { | |
2887 | unsigned long flags; | |
2888 | bool ret; | |
2889 | ||
2890 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2891 | ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len); | |
2892 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2893 | ||
2894 | return ret; | |
2895 | } | |
e2ae715d KS |
2896 | EXPORT_SYMBOL_GPL(kmsg_dump_get_line); |
2897 | ||
2898 | /** | |
2899 | * kmsg_dump_get_buffer - copy kmsg log lines | |
2900 | * @dumper: registered kmsg dumper | |
2901 | * @syslog: include the "<4>" prefixes | |
4f0f4af5 | 2902 | * @buf: buffer to copy the line to |
e2ae715d KS |
2903 | * @size: maximum size of the buffer |
2904 | * @len: length of line placed into buffer | |
2905 | * | |
2906 | * Start at the end of the kmsg buffer and fill the provided buffer | |
2907 | * with as many of the the *youngest* kmsg records that fit into it. | |
2908 | * If the buffer is large enough, all available kmsg records will be | |
2909 | * copied with a single call. | |
2910 | * | |
2911 | * Consecutive calls will fill the buffer with the next block of | |
2912 | * available older records, not including the earlier retrieved ones. | |
2913 | * | |
2914 | * A return value of FALSE indicates that there are no more records to | |
2915 | * read. | |
2916 | */ | |
2917 | bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, | |
2918 | char *buf, size_t size, size_t *len) | |
2919 | { | |
2920 | unsigned long flags; | |
2921 | u64 seq; | |
2922 | u32 idx; | |
2923 | u64 next_seq; | |
2924 | u32 next_idx; | |
5becfb1d | 2925 | enum log_flags prev; |
e2ae715d KS |
2926 | size_t l = 0; |
2927 | bool ret = false; | |
2928 | ||
2929 | if (!dumper->active) | |
2930 | goto out; | |
2931 | ||
2932 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2933 | if (dumper->cur_seq < log_first_seq) { | |
2934 | /* messages are gone, move to first available one */ | |
2935 | dumper->cur_seq = log_first_seq; | |
2936 | dumper->cur_idx = log_first_idx; | |
2937 | } | |
2938 | ||
2939 | /* last entry */ | |
2940 | if (dumper->cur_seq >= dumper->next_seq) { | |
2941 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2942 | goto out; | |
2943 | } | |
2944 | ||
2945 | /* calculate length of entire buffer */ | |
2946 | seq = dumper->cur_seq; | |
2947 | idx = dumper->cur_idx; | |
5becfb1d | 2948 | prev = 0; |
e2ae715d | 2949 | while (seq < dumper->next_seq) { |
62e32ac3 | 2950 | struct printk_log *msg = log_from_idx(idx); |
e2ae715d | 2951 | |
5becfb1d | 2952 | l += msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
2953 | idx = log_next(idx); |
2954 | seq++; | |
5becfb1d | 2955 | prev = msg->flags; |
e2ae715d KS |
2956 | } |
2957 | ||
2958 | /* move first record forward until length fits into the buffer */ | |
2959 | seq = dumper->cur_seq; | |
2960 | idx = dumper->cur_idx; | |
5becfb1d | 2961 | prev = 0; |
e2ae715d | 2962 | while (l > size && seq < dumper->next_seq) { |
62e32ac3 | 2963 | struct printk_log *msg = log_from_idx(idx); |
456b565c | 2964 | |
5becfb1d | 2965 | l -= msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
2966 | idx = log_next(idx); |
2967 | seq++; | |
5becfb1d | 2968 | prev = msg->flags; |
456b565c | 2969 | } |
e2ae715d KS |
2970 | |
2971 | /* last message in next interation */ | |
2972 | next_seq = seq; | |
2973 | next_idx = idx; | |
2974 | ||
2975 | l = 0; | |
2976 | while (seq < dumper->next_seq) { | |
62e32ac3 | 2977 | struct printk_log *msg = log_from_idx(idx); |
e2ae715d | 2978 | |
5becfb1d | 2979 | l += msg_print_text(msg, prev, syslog, buf + l, size - l); |
e2ae715d KS |
2980 | idx = log_next(idx); |
2981 | seq++; | |
5becfb1d | 2982 | prev = msg->flags; |
e2ae715d KS |
2983 | } |
2984 | ||
2985 | dumper->next_seq = next_seq; | |
2986 | dumper->next_idx = next_idx; | |
2987 | ret = true; | |
7ff9554b | 2988 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
e2ae715d KS |
2989 | out: |
2990 | if (len) | |
2991 | *len = l; | |
2992 | return ret; | |
2993 | } | |
2994 | EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); | |
456b565c | 2995 | |
533827c9 AV |
2996 | /** |
2997 | * kmsg_dump_rewind_nolock - reset the interator (unlocked version) | |
2998 | * @dumper: registered kmsg dumper | |
2999 | * | |
3000 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
3001 | * kmsg_dump_get_buffer() can be called again and used multiple | |
3002 | * times within the same dumper.dump() callback. | |
3003 | * | |
3004 | * The function is similar to kmsg_dump_rewind(), but grabs no locks. | |
3005 | */ | |
3006 | void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) | |
3007 | { | |
3008 | dumper->cur_seq = clear_seq; | |
3009 | dumper->cur_idx = clear_idx; | |
3010 | dumper->next_seq = log_next_seq; | |
3011 | dumper->next_idx = log_next_idx; | |
3012 | } | |
3013 | ||
e2ae715d KS |
3014 | /** |
3015 | * kmsg_dump_rewind - reset the interator | |
3016 | * @dumper: registered kmsg dumper | |
3017 | * | |
3018 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
3019 | * kmsg_dump_get_buffer() can be called again and used multiple | |
3020 | * times within the same dumper.dump() callback. | |
3021 | */ | |
3022 | void kmsg_dump_rewind(struct kmsg_dumper *dumper) | |
3023 | { | |
3024 | unsigned long flags; | |
3025 | ||
3026 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
533827c9 | 3027 | kmsg_dump_rewind_nolock(dumper); |
e2ae715d | 3028 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
456b565c | 3029 | } |
e2ae715d | 3030 | EXPORT_SYMBOL_GPL(kmsg_dump_rewind); |
196779b9 | 3031 | |
98e5e1bf TH |
3032 | static char dump_stack_arch_desc_str[128]; |
3033 | ||
3034 | /** | |
3035 | * dump_stack_set_arch_desc - set arch-specific str to show with task dumps | |
3036 | * @fmt: printf-style format string | |
3037 | * @...: arguments for the format string | |
3038 | * | |
3039 | * The configured string will be printed right after utsname during task | |
3040 | * dumps. Usually used to add arch-specific system identifiers. If an | |
3041 | * arch wants to make use of such an ID string, it should initialize this | |
3042 | * as soon as possible during boot. | |
3043 | */ | |
3044 | void __init dump_stack_set_arch_desc(const char *fmt, ...) | |
3045 | { | |
3046 | va_list args; | |
3047 | ||
3048 | va_start(args, fmt); | |
3049 | vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), | |
3050 | fmt, args); | |
3051 | va_end(args); | |
3052 | } | |
3053 | ||
196779b9 TH |
3054 | /** |
3055 | * dump_stack_print_info - print generic debug info for dump_stack() | |
3056 | * @log_lvl: log level | |
3057 | * | |
3058 | * Arch-specific dump_stack() implementations can use this function to | |
3059 | * print out the same debug information as the generic dump_stack(). | |
3060 | */ | |
3061 | void dump_stack_print_info(const char *log_lvl) | |
3062 | { | |
3063 | printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n", | |
3064 | log_lvl, raw_smp_processor_id(), current->pid, current->comm, | |
3065 | print_tainted(), init_utsname()->release, | |
3066 | (int)strcspn(init_utsname()->version, " "), | |
3067 | init_utsname()->version); | |
98e5e1bf TH |
3068 | |
3069 | if (dump_stack_arch_desc_str[0] != '\0') | |
3070 | printk("%sHardware name: %s\n", | |
3071 | log_lvl, dump_stack_arch_desc_str); | |
3d1cb205 TH |
3072 | |
3073 | print_worker_info(log_lvl, current); | |
196779b9 TH |
3074 | } |
3075 | ||
a43cb95d TH |
3076 | /** |
3077 | * show_regs_print_info - print generic debug info for show_regs() | |
3078 | * @log_lvl: log level | |
3079 | * | |
3080 | * show_regs() implementations can use this function to print out generic | |
3081 | * debug information. | |
3082 | */ | |
3083 | void show_regs_print_info(const char *log_lvl) | |
3084 | { | |
3085 | dump_stack_print_info(log_lvl); | |
3086 | ||
3087 | printk("%stask: %p ti: %p task.ti: %p\n", | |
3088 | log_lvl, current, current_thread_info(), | |
3089 | task_thread_info(current)); | |
3090 | } | |
3091 | ||
7ef3d2fd | 3092 | #endif |