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> |
a27bb332 | 35 | #include <linux/aio.h> |
1da177e4 | 36 | #include <linux/syscalls.h> |
04d491ab | 37 | #include <linux/kexec.h> |
d37d39ae | 38 | #include <linux/kdb.h> |
3fff4c42 | 39 | #include <linux/ratelimit.h> |
456b565c | 40 | #include <linux/kmsg_dump.h> |
00234592 | 41 | #include <linux/syslog.h> |
034260d6 KC |
42 | #include <linux/cpu.h> |
43 | #include <linux/notifier.h> | |
fb842b00 | 44 | #include <linux/rculist.h> |
e11fea92 | 45 | #include <linux/poll.h> |
74876a98 | 46 | #include <linux/irq_work.h> |
196779b9 | 47 | #include <linux/utsname.h> |
1da177e4 LT |
48 | |
49 | #include <asm/uaccess.h> | |
50 | ||
95100358 JB |
51 | #define CREATE_TRACE_POINTS |
52 | #include <trace/events/printk.h> | |
53 | ||
d197c43d | 54 | #include "console_cmdline.h" |
bbeddf52 | 55 | #include "braille.h" |
d197c43d | 56 | |
1da177e4 | 57 | /* printk's without a loglevel use this.. */ |
5af5bcb8 | 58 | #define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL |
1da177e4 LT |
59 | |
60 | /* We show everything that is MORE important than this.. */ | |
61 | #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */ | |
62 | #define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */ | |
63 | ||
1da177e4 LT |
64 | int console_printk[4] = { |
65 | DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */ | |
66 | DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */ | |
67 | MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */ | |
68 | DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */ | |
69 | }; | |
70 | ||
1da177e4 | 71 | /* |
0bbfb7c2 | 72 | * Low level drivers may need that to know if they can schedule in |
1da177e4 LT |
73 | * their unblank() callback or not. So let's export it. |
74 | */ | |
75 | int oops_in_progress; | |
76 | EXPORT_SYMBOL(oops_in_progress); | |
77 | ||
78 | /* | |
79 | * console_sem protects the console_drivers list, and also | |
80 | * provides serialisation for access to the entire console | |
81 | * driver system. | |
82 | */ | |
5b8c4f23 | 83 | static DEFINE_SEMAPHORE(console_sem); |
1da177e4 | 84 | struct console *console_drivers; |
a29d1cfe IM |
85 | EXPORT_SYMBOL_GPL(console_drivers); |
86 | ||
daee7797 DV |
87 | #ifdef CONFIG_LOCKDEP |
88 | static struct lockdep_map console_lock_dep_map = { | |
89 | .name = "console_lock" | |
90 | }; | |
91 | #endif | |
92 | ||
1da177e4 LT |
93 | /* |
94 | * This is used for debugging the mess that is the VT code by | |
95 | * keeping track if we have the console semaphore held. It's | |
96 | * definitely not the perfect debug tool (we don't know if _WE_ | |
97 | * hold it are racing, but it helps tracking those weird code | |
98 | * path in the console code where we end up in places I want | |
99 | * locked without the console sempahore held | |
100 | */ | |
557240b4 | 101 | static int console_locked, console_suspended; |
1da177e4 | 102 | |
fe3d8ad3 FT |
103 | /* |
104 | * If exclusive_console is non-NULL then only this console is to be printed to. | |
105 | */ | |
106 | static struct console *exclusive_console; | |
107 | ||
1da177e4 LT |
108 | /* |
109 | * Array of consoles built from command line options (console=) | |
110 | */ | |
1da177e4 LT |
111 | |
112 | #define MAX_CMDLINECONSOLES 8 | |
113 | ||
114 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; | |
d197c43d | 115 | |
1da177e4 LT |
116 | static int selected_console = -1; |
117 | static int preferred_console = -1; | |
9e124fe1 MA |
118 | int console_set_on_cmdline; |
119 | EXPORT_SYMBOL(console_set_on_cmdline); | |
1da177e4 LT |
120 | |
121 | /* Flag: console code may call schedule() */ | |
122 | static int console_may_schedule; | |
123 | ||
7ff9554b KS |
124 | /* |
125 | * The printk log buffer consists of a chain of concatenated variable | |
126 | * length records. Every record starts with a record header, containing | |
127 | * the overall length of the record. | |
128 | * | |
129 | * The heads to the first and last entry in the buffer, as well as the | |
130 | * sequence numbers of these both entries are maintained when messages | |
131 | * are stored.. | |
132 | * | |
133 | * If the heads indicate available messages, the length in the header | |
134 | * tells the start next message. A length == 0 for the next message | |
135 | * indicates a wrap-around to the beginning of the buffer. | |
136 | * | |
137 | * Every record carries the monotonic timestamp in microseconds, as well as | |
138 | * the standard userspace syslog level and syslog facility. The usual | |
139 | * kernel messages use LOG_KERN; userspace-injected messages always carry | |
140 | * a matching syslog facility, by default LOG_USER. The origin of every | |
141 | * message can be reliably determined that way. | |
142 | * | |
143 | * The human readable log message directly follows the message header. The | |
144 | * length of the message text is stored in the header, the stored message | |
145 | * is not terminated. | |
146 | * | |
e11fea92 KS |
147 | * Optionally, a message can carry a dictionary of properties (key/value pairs), |
148 | * to provide userspace with a machine-readable message context. | |
149 | * | |
150 | * Examples for well-defined, commonly used property names are: | |
151 | * DEVICE=b12:8 device identifier | |
152 | * b12:8 block dev_t | |
153 | * c127:3 char dev_t | |
154 | * n8 netdev ifindex | |
155 | * +sound:card0 subsystem:devname | |
156 | * SUBSYSTEM=pci driver-core subsystem name | |
157 | * | |
158 | * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value | |
159 | * follows directly after a '=' character. Every property is terminated by | |
160 | * a '\0' character. The last property is not terminated. | |
161 | * | |
162 | * Example of a message structure: | |
163 | * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec | |
164 | * 0008 34 00 record is 52 bytes long | |
165 | * 000a 0b 00 text is 11 bytes long | |
166 | * 000c 1f 00 dictionary is 23 bytes long | |
167 | * 000e 03 00 LOG_KERN (facility) LOG_ERR (level) | |
168 | * 0010 69 74 27 73 20 61 20 6c "it's a l" | |
169 | * 69 6e 65 "ine" | |
170 | * 001b 44 45 56 49 43 "DEVIC" | |
171 | * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D" | |
172 | * 52 49 56 45 52 3d 62 75 "RIVER=bu" | |
173 | * 67 "g" | |
174 | * 0032 00 00 00 padding to next message header | |
175 | * | |
62e32ac3 | 176 | * The 'struct printk_log' buffer header must never be directly exported to |
e11fea92 KS |
177 | * userspace, it is a kernel-private implementation detail that might |
178 | * need to be changed in the future, when the requirements change. | |
179 | * | |
180 | * /dev/kmsg exports the structured data in the following line format: | |
181 | * "level,sequnum,timestamp;<message text>\n" | |
182 | * | |
183 | * The optional key/value pairs are attached as continuation lines starting | |
184 | * with a space character and terminated by a newline. All possible | |
185 | * non-prinatable characters are escaped in the "\xff" notation. | |
186 | * | |
187 | * Users of the export format should ignore possible additional values | |
188 | * separated by ',', and find the message after the ';' character. | |
7ff9554b KS |
189 | */ |
190 | ||
084681d1 | 191 | enum log_flags { |
5becfb1d KS |
192 | LOG_NOCONS = 1, /* already flushed, do not print to console */ |
193 | LOG_NEWLINE = 2, /* text ended with a newline */ | |
194 | LOG_PREFIX = 4, /* text started with a prefix */ | |
195 | LOG_CONT = 8, /* text is a fragment of a continuation line */ | |
084681d1 KS |
196 | }; |
197 | ||
62e32ac3 | 198 | struct printk_log { |
7ff9554b KS |
199 | u64 ts_nsec; /* timestamp in nanoseconds */ |
200 | u16 len; /* length of entire record */ | |
201 | u16 text_len; /* length of text buffer */ | |
202 | u16 dict_len; /* length of dictionary buffer */ | |
084681d1 KS |
203 | u8 facility; /* syslog facility */ |
204 | u8 flags:5; /* internal record flags */ | |
205 | u8 level:3; /* syslog level */ | |
7ff9554b KS |
206 | }; |
207 | ||
208 | /* | |
ca1d432a | 209 | * The logbuf_lock protects kmsg buffer, indices, counters. |
7ff9554b KS |
210 | */ |
211 | static DEFINE_RAW_SPINLOCK(logbuf_lock); | |
d59745ce | 212 | |
96efedf1 | 213 | #ifdef CONFIG_PRINTK |
dc72c32e | 214 | DECLARE_WAIT_QUEUE_HEAD(log_wait); |
7f3a781d KS |
215 | /* the next printk record to read by syslog(READ) or /proc/kmsg */ |
216 | static u64 syslog_seq; | |
217 | static u32 syslog_idx; | |
5becfb1d | 218 | static enum log_flags syslog_prev; |
eb02dac9 | 219 | static size_t syslog_partial; |
7ff9554b KS |
220 | |
221 | /* index and sequence number of the first record stored in the buffer */ | |
222 | static u64 log_first_seq; | |
223 | static u32 log_first_idx; | |
224 | ||
225 | /* index and sequence number of the next record to store in the buffer */ | |
226 | static u64 log_next_seq; | |
227 | static u32 log_next_idx; | |
228 | ||
eab07260 KS |
229 | /* the next printk record to write to the console */ |
230 | static u64 console_seq; | |
231 | static u32 console_idx; | |
232 | static enum log_flags console_prev; | |
233 | ||
7ff9554b KS |
234 | /* the next printk record to read after the last 'clear' command */ |
235 | static u64 clear_seq; | |
236 | static u32 clear_idx; | |
237 | ||
70498253 KS |
238 | #define PREFIX_MAX 32 |
239 | #define LOG_LINE_MAX 1024 - PREFIX_MAX | |
7f3a781d KS |
240 | |
241 | /* record buffer */ | |
6ebb017d | 242 | #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) |
f8450fca SW |
243 | #define LOG_ALIGN 4 |
244 | #else | |
62e32ac3 | 245 | #define LOG_ALIGN __alignof__(struct printk_log) |
f8450fca | 246 | #endif |
7f3a781d | 247 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
f8450fca | 248 | static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); |
7f3a781d KS |
249 | static char *log_buf = __log_buf; |
250 | static u32 log_buf_len = __LOG_BUF_LEN; | |
251 | ||
252 | /* cpu currently holding logbuf_lock */ | |
253 | static volatile unsigned int logbuf_cpu = UINT_MAX; | |
7ff9554b KS |
254 | |
255 | /* human readable text of the record */ | |
62e32ac3 | 256 | static char *log_text(const struct printk_log *msg) |
7ff9554b | 257 | { |
62e32ac3 | 258 | return (char *)msg + sizeof(struct printk_log); |
7ff9554b KS |
259 | } |
260 | ||
261 | /* optional key/value pair dictionary attached to the record */ | |
62e32ac3 | 262 | static char *log_dict(const struct printk_log *msg) |
7ff9554b | 263 | { |
62e32ac3 | 264 | return (char *)msg + sizeof(struct printk_log) + msg->text_len; |
7ff9554b KS |
265 | } |
266 | ||
267 | /* get record by index; idx must point to valid msg */ | |
62e32ac3 | 268 | static struct printk_log *log_from_idx(u32 idx) |
7ff9554b | 269 | { |
62e32ac3 | 270 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
271 | |
272 | /* | |
273 | * A length == 0 record is the end of buffer marker. Wrap around and | |
274 | * read the message at the start of the buffer. | |
275 | */ | |
276 | if (!msg->len) | |
62e32ac3 | 277 | return (struct printk_log *)log_buf; |
7ff9554b KS |
278 | return msg; |
279 | } | |
280 | ||
281 | /* get next record; idx must point to valid msg */ | |
282 | static u32 log_next(u32 idx) | |
283 | { | |
62e32ac3 | 284 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
285 | |
286 | /* length == 0 indicates the end of the buffer; wrap */ | |
287 | /* | |
288 | * A length == 0 record is the end of buffer marker. Wrap around and | |
289 | * read the message at the start of the buffer as *this* one, and | |
290 | * return the one after that. | |
291 | */ | |
292 | if (!msg->len) { | |
62e32ac3 | 293 | msg = (struct printk_log *)log_buf; |
7ff9554b KS |
294 | return msg->len; |
295 | } | |
296 | return idx + msg->len; | |
297 | } | |
298 | ||
f40e4b9f PM |
299 | /* |
300 | * Check whether there is enough free space for the given message. | |
301 | * | |
302 | * The same values of first_idx and next_idx mean that the buffer | |
303 | * is either empty or full. | |
304 | * | |
305 | * If the buffer is empty, we must respect the position of the indexes. | |
306 | * They cannot be reset to the beginning of the buffer. | |
307 | */ | |
308 | static int logbuf_has_space(u32 msg_size, bool empty) | |
0a581694 PM |
309 | { |
310 | u32 free; | |
311 | ||
f40e4b9f | 312 | if (log_next_idx > log_first_idx || empty) |
0a581694 PM |
313 | free = max(log_buf_len - log_next_idx, log_first_idx); |
314 | else | |
315 | free = log_first_idx - log_next_idx; | |
316 | ||
317 | /* | |
318 | * We need space also for an empty header that signalizes wrapping | |
319 | * of the buffer. | |
320 | */ | |
321 | return free >= msg_size + sizeof(struct printk_log); | |
322 | } | |
323 | ||
f40e4b9f | 324 | static int log_make_free_space(u32 msg_size) |
0a581694 PM |
325 | { |
326 | while (log_first_seq < log_next_seq) { | |
f40e4b9f PM |
327 | if (logbuf_has_space(msg_size, false)) |
328 | return 0; | |
0a581694 PM |
329 | /* drop old messages until we have enough continuous space */ |
330 | log_first_idx = log_next(log_first_idx); | |
331 | log_first_seq++; | |
332 | } | |
f40e4b9f PM |
333 | |
334 | /* sequence numbers are equal, so the log buffer is empty */ | |
335 | if (logbuf_has_space(msg_size, true)) | |
336 | return 0; | |
337 | ||
338 | return -ENOMEM; | |
0a581694 PM |
339 | } |
340 | ||
85c87043 PM |
341 | /* compute the message size including the padding bytes */ |
342 | static u32 msg_used_size(u16 text_len, u16 dict_len, u32 *pad_len) | |
343 | { | |
344 | u32 size; | |
345 | ||
346 | size = sizeof(struct printk_log) + text_len + dict_len; | |
347 | *pad_len = (-size) & (LOG_ALIGN - 1); | |
348 | size += *pad_len; | |
349 | ||
350 | return size; | |
351 | } | |
352 | ||
55bd53a4 PM |
353 | /* |
354 | * Define how much of the log buffer we could take at maximum. The value | |
355 | * must be greater than two. Note that only half of the buffer is available | |
356 | * when the index points to the middle. | |
357 | */ | |
358 | #define MAX_LOG_TAKE_PART 4 | |
359 | static const char trunc_msg[] = "<truncated>"; | |
360 | ||
361 | static u32 truncate_msg(u16 *text_len, u16 *trunc_msg_len, | |
362 | u16 *dict_len, u32 *pad_len) | |
363 | { | |
364 | /* | |
365 | * The message should not take the whole buffer. Otherwise, it might | |
366 | * get removed too soon. | |
367 | */ | |
368 | u32 max_text_len = log_buf_len / MAX_LOG_TAKE_PART; | |
369 | if (*text_len > max_text_len) | |
370 | *text_len = max_text_len; | |
371 | /* enable the warning message */ | |
372 | *trunc_msg_len = strlen(trunc_msg); | |
373 | /* disable the "dict" completely */ | |
374 | *dict_len = 0; | |
375 | /* compute the size again, count also the warning message */ | |
376 | return msg_used_size(*text_len + *trunc_msg_len, 0, pad_len); | |
377 | } | |
378 | ||
7ff9554b | 379 | /* insert record into the buffer, discard old ones, update heads */ |
034633cc PM |
380 | static int log_store(int facility, int level, |
381 | enum log_flags flags, u64 ts_nsec, | |
382 | const char *dict, u16 dict_len, | |
383 | const char *text, u16 text_len) | |
7ff9554b | 384 | { |
62e32ac3 | 385 | struct printk_log *msg; |
7ff9554b | 386 | u32 size, pad_len; |
55bd53a4 | 387 | u16 trunc_msg_len = 0; |
7ff9554b KS |
388 | |
389 | /* number of '\0' padding bytes to next message */ | |
85c87043 | 390 | size = msg_used_size(text_len, dict_len, &pad_len); |
7ff9554b | 391 | |
55bd53a4 PM |
392 | if (log_make_free_space(size)) { |
393 | /* truncate the message if it is too long for empty buffer */ | |
394 | size = truncate_msg(&text_len, &trunc_msg_len, | |
395 | &dict_len, &pad_len); | |
396 | /* survive when the log buffer is too small for trunc_msg */ | |
397 | if (log_make_free_space(size)) | |
034633cc | 398 | return 0; |
55bd53a4 | 399 | } |
7ff9554b | 400 | |
39b25109 | 401 | if (log_next_idx + size + sizeof(struct printk_log) > log_buf_len) { |
7ff9554b KS |
402 | /* |
403 | * This message + an additional empty header does not fit | |
404 | * at the end of the buffer. Add an empty header with len == 0 | |
405 | * to signify a wrap around. | |
406 | */ | |
62e32ac3 | 407 | memset(log_buf + log_next_idx, 0, sizeof(struct printk_log)); |
7ff9554b KS |
408 | log_next_idx = 0; |
409 | } | |
410 | ||
411 | /* fill message */ | |
62e32ac3 | 412 | msg = (struct printk_log *)(log_buf + log_next_idx); |
7ff9554b KS |
413 | memcpy(log_text(msg), text, text_len); |
414 | msg->text_len = text_len; | |
55bd53a4 PM |
415 | if (trunc_msg_len) { |
416 | memcpy(log_text(msg) + text_len, trunc_msg, trunc_msg_len); | |
417 | msg->text_len += trunc_msg_len; | |
418 | } | |
7ff9554b KS |
419 | memcpy(log_dict(msg), dict, dict_len); |
420 | msg->dict_len = dict_len; | |
084681d1 KS |
421 | msg->facility = facility; |
422 | msg->level = level & 7; | |
423 | msg->flags = flags & 0x1f; | |
424 | if (ts_nsec > 0) | |
425 | msg->ts_nsec = ts_nsec; | |
426 | else | |
427 | msg->ts_nsec = local_clock(); | |
7ff9554b | 428 | memset(log_dict(msg) + dict_len, 0, pad_len); |
fce6e033 | 429 | msg->len = size; |
7ff9554b KS |
430 | |
431 | /* insert message */ | |
432 | log_next_idx += msg->len; | |
433 | log_next_seq++; | |
034633cc PM |
434 | |
435 | return msg->text_len; | |
7ff9554b | 436 | } |
d59745ce | 437 | |
637241a9 KC |
438 | #ifdef CONFIG_SECURITY_DMESG_RESTRICT |
439 | int dmesg_restrict = 1; | |
440 | #else | |
441 | int dmesg_restrict; | |
442 | #endif | |
443 | ||
444 | static int syslog_action_restricted(int type) | |
445 | { | |
446 | if (dmesg_restrict) | |
447 | return 1; | |
448 | /* | |
449 | * Unless restricted, we allow "read all" and "get buffer size" | |
450 | * for everybody. | |
451 | */ | |
452 | return type != SYSLOG_ACTION_READ_ALL && | |
453 | type != SYSLOG_ACTION_SIZE_BUFFER; | |
454 | } | |
455 | ||
456 | static int check_syslog_permissions(int type, bool from_file) | |
457 | { | |
458 | /* | |
459 | * If this is from /proc/kmsg and we've already opened it, then we've | |
460 | * already done the capabilities checks at open time. | |
461 | */ | |
462 | if (from_file && type != SYSLOG_ACTION_OPEN) | |
463 | return 0; | |
464 | ||
465 | if (syslog_action_restricted(type)) { | |
466 | if (capable(CAP_SYSLOG)) | |
467 | return 0; | |
468 | /* | |
469 | * For historical reasons, accept CAP_SYS_ADMIN too, with | |
470 | * a warning. | |
471 | */ | |
472 | if (capable(CAP_SYS_ADMIN)) { | |
473 | pr_warn_once("%s (%d): Attempt to access syslog with " | |
474 | "CAP_SYS_ADMIN but no CAP_SYSLOG " | |
475 | "(deprecated).\n", | |
476 | current->comm, task_pid_nr(current)); | |
477 | return 0; | |
478 | } | |
479 | return -EPERM; | |
480 | } | |
481 | return security_syslog(type); | |
482 | } | |
483 | ||
484 | ||
e11fea92 KS |
485 | /* /dev/kmsg - userspace message inject/listen interface */ |
486 | struct devkmsg_user { | |
487 | u64 seq; | |
488 | u32 idx; | |
d39f3d77 | 489 | enum log_flags prev; |
e11fea92 KS |
490 | struct mutex lock; |
491 | char buf[8192]; | |
492 | }; | |
493 | ||
494 | static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv, | |
495 | unsigned long count, loff_t pos) | |
496 | { | |
497 | char *buf, *line; | |
498 | int i; | |
499 | int level = default_message_loglevel; | |
500 | int facility = 1; /* LOG_USER */ | |
501 | size_t len = iov_length(iv, count); | |
502 | ssize_t ret = len; | |
503 | ||
504 | if (len > LOG_LINE_MAX) | |
505 | return -EINVAL; | |
506 | buf = kmalloc(len+1, GFP_KERNEL); | |
507 | if (buf == NULL) | |
508 | return -ENOMEM; | |
509 | ||
510 | line = buf; | |
511 | for (i = 0; i < count; i++) { | |
cdf53441 KS |
512 | if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) { |
513 | ret = -EFAULT; | |
e11fea92 | 514 | goto out; |
cdf53441 | 515 | } |
e11fea92 KS |
516 | line += iv[i].iov_len; |
517 | } | |
518 | ||
519 | /* | |
520 | * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace | |
521 | * the decimal value represents 32bit, the lower 3 bit are the log | |
522 | * level, the rest are the log facility. | |
523 | * | |
524 | * If no prefix or no userspace facility is specified, we | |
525 | * enforce LOG_USER, to be able to reliably distinguish | |
526 | * kernel-generated messages from userspace-injected ones. | |
527 | */ | |
528 | line = buf; | |
529 | if (line[0] == '<') { | |
530 | char *endp = NULL; | |
531 | ||
532 | i = simple_strtoul(line+1, &endp, 10); | |
533 | if (endp && endp[0] == '>') { | |
534 | level = i & 7; | |
535 | if (i >> 3) | |
536 | facility = i >> 3; | |
537 | endp++; | |
538 | len -= endp - line; | |
539 | line = endp; | |
540 | } | |
541 | } | |
542 | line[len] = '\0'; | |
543 | ||
544 | printk_emit(facility, level, NULL, 0, "%s", line); | |
545 | out: | |
546 | kfree(buf); | |
547 | return ret; | |
548 | } | |
549 | ||
550 | static ssize_t devkmsg_read(struct file *file, char __user *buf, | |
551 | size_t count, loff_t *ppos) | |
552 | { | |
553 | struct devkmsg_user *user = file->private_data; | |
62e32ac3 | 554 | struct printk_log *msg; |
5fc32490 | 555 | u64 ts_usec; |
e11fea92 | 556 | size_t i; |
d39f3d77 | 557 | char cont = '-'; |
e11fea92 KS |
558 | size_t len; |
559 | ssize_t ret; | |
560 | ||
561 | if (!user) | |
562 | return -EBADF; | |
563 | ||
4a77a5a0 YL |
564 | ret = mutex_lock_interruptible(&user->lock); |
565 | if (ret) | |
566 | return ret; | |
5c53d819 | 567 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
568 | while (user->seq == log_next_seq) { |
569 | if (file->f_flags & O_NONBLOCK) { | |
570 | ret = -EAGAIN; | |
5c53d819 | 571 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
572 | goto out; |
573 | } | |
574 | ||
5c53d819 | 575 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
576 | ret = wait_event_interruptible(log_wait, |
577 | user->seq != log_next_seq); | |
578 | if (ret) | |
579 | goto out; | |
5c53d819 | 580 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
581 | } |
582 | ||
583 | if (user->seq < log_first_seq) { | |
584 | /* our last seen message is gone, return error and reset */ | |
585 | user->idx = log_first_idx; | |
586 | user->seq = log_first_seq; | |
587 | ret = -EPIPE; | |
5c53d819 | 588 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
589 | goto out; |
590 | } | |
591 | ||
592 | msg = log_from_idx(user->idx); | |
5fc32490 KS |
593 | ts_usec = msg->ts_nsec; |
594 | do_div(ts_usec, 1000); | |
d39f3d77 KS |
595 | |
596 | /* | |
597 | * If we couldn't merge continuation line fragments during the print, | |
598 | * export the stored flags to allow an optional external merge of the | |
599 | * records. Merging the records isn't always neccessarily correct, like | |
600 | * when we hit a race during printing. In most cases though, it produces | |
601 | * better readable output. 'c' in the record flags mark the first | |
602 | * fragment of a line, '+' the following. | |
603 | */ | |
604 | if (msg->flags & LOG_CONT && !(user->prev & LOG_CONT)) | |
605 | cont = 'c'; | |
606 | else if ((msg->flags & LOG_CONT) || | |
607 | ((user->prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))) | |
608 | cont = '+'; | |
609 | ||
610 | len = sprintf(user->buf, "%u,%llu,%llu,%c;", | |
611 | (msg->facility << 3) | msg->level, | |
612 | user->seq, ts_usec, cont); | |
613 | user->prev = msg->flags; | |
e11fea92 KS |
614 | |
615 | /* escape non-printable characters */ | |
616 | for (i = 0; i < msg->text_len; i++) { | |
3ce9a7c0 | 617 | unsigned char c = log_text(msg)[i]; |
e11fea92 | 618 | |
e3f5a5f2 | 619 | if (c < ' ' || c >= 127 || c == '\\') |
e11fea92 KS |
620 | len += sprintf(user->buf + len, "\\x%02x", c); |
621 | else | |
622 | user->buf[len++] = c; | |
623 | } | |
624 | user->buf[len++] = '\n'; | |
625 | ||
626 | if (msg->dict_len) { | |
627 | bool line = true; | |
628 | ||
629 | for (i = 0; i < msg->dict_len; i++) { | |
3ce9a7c0 | 630 | unsigned char c = log_dict(msg)[i]; |
e11fea92 KS |
631 | |
632 | if (line) { | |
633 | user->buf[len++] = ' '; | |
634 | line = false; | |
635 | } | |
636 | ||
637 | if (c == '\0') { | |
638 | user->buf[len++] = '\n'; | |
639 | line = true; | |
640 | continue; | |
641 | } | |
642 | ||
e3f5a5f2 | 643 | if (c < ' ' || c >= 127 || c == '\\') { |
e11fea92 KS |
644 | len += sprintf(user->buf + len, "\\x%02x", c); |
645 | continue; | |
646 | } | |
647 | ||
648 | user->buf[len++] = c; | |
649 | } | |
650 | user->buf[len++] = '\n'; | |
651 | } | |
652 | ||
653 | user->idx = log_next(user->idx); | |
654 | user->seq++; | |
5c53d819 | 655 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
656 | |
657 | if (len > count) { | |
658 | ret = -EINVAL; | |
659 | goto out; | |
660 | } | |
661 | ||
662 | if (copy_to_user(buf, user->buf, len)) { | |
663 | ret = -EFAULT; | |
664 | goto out; | |
665 | } | |
666 | ret = len; | |
667 | out: | |
668 | mutex_unlock(&user->lock); | |
669 | return ret; | |
670 | } | |
671 | ||
672 | static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) | |
673 | { | |
674 | struct devkmsg_user *user = file->private_data; | |
675 | loff_t ret = 0; | |
676 | ||
677 | if (!user) | |
678 | return -EBADF; | |
679 | if (offset) | |
680 | return -ESPIPE; | |
681 | ||
5c53d819 | 682 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
683 | switch (whence) { |
684 | case SEEK_SET: | |
685 | /* the first record */ | |
686 | user->idx = log_first_idx; | |
687 | user->seq = log_first_seq; | |
688 | break; | |
689 | case SEEK_DATA: | |
690 | /* | |
691 | * The first record after the last SYSLOG_ACTION_CLEAR, | |
692 | * like issued by 'dmesg -c'. Reading /dev/kmsg itself | |
693 | * changes no global state, and does not clear anything. | |
694 | */ | |
695 | user->idx = clear_idx; | |
696 | user->seq = clear_seq; | |
697 | break; | |
698 | case SEEK_END: | |
699 | /* after the last record */ | |
700 | user->idx = log_next_idx; | |
701 | user->seq = log_next_seq; | |
702 | break; | |
703 | default: | |
704 | ret = -EINVAL; | |
705 | } | |
5c53d819 | 706 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
707 | return ret; |
708 | } | |
709 | ||
710 | static unsigned int devkmsg_poll(struct file *file, poll_table *wait) | |
711 | { | |
712 | struct devkmsg_user *user = file->private_data; | |
713 | int ret = 0; | |
714 | ||
715 | if (!user) | |
716 | return POLLERR|POLLNVAL; | |
717 | ||
718 | poll_wait(file, &log_wait, wait); | |
719 | ||
5c53d819 | 720 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
721 | if (user->seq < log_next_seq) { |
722 | /* return error when data has vanished underneath us */ | |
723 | if (user->seq < log_first_seq) | |
724 | ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI; | |
0a285317 NK |
725 | else |
726 | ret = POLLIN|POLLRDNORM; | |
e11fea92 | 727 | } |
5c53d819 | 728 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
729 | |
730 | return ret; | |
731 | } | |
732 | ||
733 | static int devkmsg_open(struct inode *inode, struct file *file) | |
734 | { | |
735 | struct devkmsg_user *user; | |
736 | int err; | |
737 | ||
738 | /* write-only does not need any file context */ | |
739 | if ((file->f_flags & O_ACCMODE) == O_WRONLY) | |
740 | return 0; | |
741 | ||
637241a9 KC |
742 | err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL, |
743 | SYSLOG_FROM_READER); | |
e11fea92 KS |
744 | if (err) |
745 | return err; | |
746 | ||
747 | user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL); | |
748 | if (!user) | |
749 | return -ENOMEM; | |
750 | ||
751 | mutex_init(&user->lock); | |
752 | ||
5c53d819 | 753 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
754 | user->idx = log_first_idx; |
755 | user->seq = log_first_seq; | |
5c53d819 | 756 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
757 | |
758 | file->private_data = user; | |
759 | return 0; | |
760 | } | |
761 | ||
762 | static int devkmsg_release(struct inode *inode, struct file *file) | |
763 | { | |
764 | struct devkmsg_user *user = file->private_data; | |
765 | ||
766 | if (!user) | |
767 | return 0; | |
768 | ||
769 | mutex_destroy(&user->lock); | |
770 | kfree(user); | |
771 | return 0; | |
772 | } | |
773 | ||
774 | const struct file_operations kmsg_fops = { | |
775 | .open = devkmsg_open, | |
776 | .read = devkmsg_read, | |
777 | .aio_write = devkmsg_writev, | |
778 | .llseek = devkmsg_llseek, | |
779 | .poll = devkmsg_poll, | |
780 | .release = devkmsg_release, | |
781 | }; | |
782 | ||
04d491ab NH |
783 | #ifdef CONFIG_KEXEC |
784 | /* | |
4c1ace64 | 785 | * This appends the listed symbols to /proc/vmcore |
04d491ab | 786 | * |
4c1ace64 | 787 | * /proc/vmcore is used by various utilities, like crash and makedumpfile to |
04d491ab NH |
788 | * obtain access to symbols that are otherwise very difficult to locate. These |
789 | * symbols are specifically used so that utilities can access and extract the | |
790 | * dmesg log from a vmcore file after a crash. | |
791 | */ | |
792 | void log_buf_kexec_setup(void) | |
793 | { | |
794 | VMCOREINFO_SYMBOL(log_buf); | |
04d491ab | 795 | VMCOREINFO_SYMBOL(log_buf_len); |
7ff9554b KS |
796 | VMCOREINFO_SYMBOL(log_first_idx); |
797 | VMCOREINFO_SYMBOL(log_next_idx); | |
6791457a | 798 | /* |
62e32ac3 | 799 | * Export struct printk_log size and field offsets. User space tools can |
6791457a VG |
800 | * parse it and detect any changes to structure down the line. |
801 | */ | |
62e32ac3 JP |
802 | VMCOREINFO_STRUCT_SIZE(printk_log); |
803 | VMCOREINFO_OFFSET(printk_log, ts_nsec); | |
804 | VMCOREINFO_OFFSET(printk_log, len); | |
805 | VMCOREINFO_OFFSET(printk_log, text_len); | |
806 | VMCOREINFO_OFFSET(printk_log, dict_len); | |
04d491ab NH |
807 | } |
808 | #endif | |
809 | ||
162a7e75 MT |
810 | /* requested log_buf_len from kernel cmdline */ |
811 | static unsigned long __initdata new_log_buf_len; | |
812 | ||
813 | /* save requested log_buf_len since it's too early to process it */ | |
1da177e4 LT |
814 | static int __init log_buf_len_setup(char *str) |
815 | { | |
eed4a2ab | 816 | unsigned size = memparse(str, &str); |
1da177e4 LT |
817 | |
818 | if (size) | |
819 | size = roundup_pow_of_two(size); | |
162a7e75 MT |
820 | if (size > log_buf_len) |
821 | new_log_buf_len = size; | |
822 | ||
823 | return 0; | |
1da177e4 | 824 | } |
162a7e75 MT |
825 | early_param("log_buf_len", log_buf_len_setup); |
826 | ||
827 | void __init setup_log_buf(int early) | |
828 | { | |
829 | unsigned long flags; | |
162a7e75 MT |
830 | char *new_log_buf; |
831 | int free; | |
832 | ||
833 | if (!new_log_buf_len) | |
834 | return; | |
1da177e4 | 835 | |
162a7e75 | 836 | if (early) { |
9da791df SS |
837 | new_log_buf = |
838 | memblock_virt_alloc(new_log_buf_len, PAGE_SIZE); | |
162a7e75 | 839 | } else { |
9da791df | 840 | new_log_buf = memblock_virt_alloc_nopanic(new_log_buf_len, 0); |
162a7e75 MT |
841 | } |
842 | ||
843 | if (unlikely(!new_log_buf)) { | |
844 | pr_err("log_buf_len: %ld bytes not available\n", | |
845 | new_log_buf_len); | |
846 | return; | |
847 | } | |
848 | ||
07354eb1 | 849 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
162a7e75 MT |
850 | log_buf_len = new_log_buf_len; |
851 | log_buf = new_log_buf; | |
852 | new_log_buf_len = 0; | |
7ff9554b KS |
853 | free = __LOG_BUF_LEN - log_next_idx; |
854 | memcpy(log_buf, __log_buf, __LOG_BUF_LEN); | |
07354eb1 | 855 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
162a7e75 MT |
856 | |
857 | pr_info("log_buf_len: %d\n", log_buf_len); | |
858 | pr_info("early log buf free: %d(%d%%)\n", | |
859 | free, (free * 100) / __LOG_BUF_LEN); | |
860 | } | |
1da177e4 | 861 | |
2fa72c8f AC |
862 | static bool __read_mostly ignore_loglevel; |
863 | ||
864 | static int __init ignore_loglevel_setup(char *str) | |
865 | { | |
866 | ignore_loglevel = 1; | |
27083bac | 867 | pr_info("debug: ignoring loglevel setting.\n"); |
2fa72c8f AC |
868 | |
869 | return 0; | |
870 | } | |
871 | ||
872 | early_param("ignore_loglevel", ignore_loglevel_setup); | |
873 | module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); | |
874 | MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to" | |
875 | "print all kernel messages to the console."); | |
876 | ||
bfe8df3d RD |
877 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
878 | ||
674dff65 | 879 | static int boot_delay; /* msecs delay after each printk during bootup */ |
3a3b6ed2 | 880 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
bfe8df3d RD |
881 | |
882 | static int __init boot_delay_setup(char *str) | |
883 | { | |
884 | unsigned long lpj; | |
bfe8df3d RD |
885 | |
886 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ | |
887 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; | |
888 | ||
889 | get_option(&str, &boot_delay); | |
890 | if (boot_delay > 10 * 1000) | |
891 | boot_delay = 0; | |
892 | ||
3a3b6ed2 DY |
893 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
894 | "HZ: %d, loops_per_msec: %llu\n", | |
895 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); | |
29e9d225 | 896 | return 0; |
bfe8df3d | 897 | } |
29e9d225 | 898 | early_param("boot_delay", boot_delay_setup); |
bfe8df3d | 899 | |
2fa72c8f | 900 | static void boot_delay_msec(int level) |
bfe8df3d RD |
901 | { |
902 | unsigned long long k; | |
903 | unsigned long timeout; | |
904 | ||
2fa72c8f AC |
905 | if ((boot_delay == 0 || system_state != SYSTEM_BOOTING) |
906 | || (level >= console_loglevel && !ignore_loglevel)) { | |
bfe8df3d | 907 | return; |
2fa72c8f | 908 | } |
bfe8df3d | 909 | |
3a3b6ed2 | 910 | k = (unsigned long long)loops_per_msec * boot_delay; |
bfe8df3d RD |
911 | |
912 | timeout = jiffies + msecs_to_jiffies(boot_delay); | |
913 | while (k) { | |
914 | k--; | |
915 | cpu_relax(); | |
916 | /* | |
917 | * use (volatile) jiffies to prevent | |
918 | * compiler reduction; loop termination via jiffies | |
919 | * is secondary and may or may not happen. | |
920 | */ | |
921 | if (time_after(jiffies, timeout)) | |
922 | break; | |
923 | touch_nmi_watchdog(); | |
924 | } | |
925 | } | |
926 | #else | |
2fa72c8f | 927 | static inline void boot_delay_msec(int level) |
bfe8df3d RD |
928 | { |
929 | } | |
930 | #endif | |
931 | ||
7ff9554b KS |
932 | #if defined(CONFIG_PRINTK_TIME) |
933 | static bool printk_time = 1; | |
934 | #else | |
935 | static bool printk_time; | |
936 | #endif | |
937 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); | |
938 | ||
084681d1 KS |
939 | static size_t print_time(u64 ts, char *buf) |
940 | { | |
941 | unsigned long rem_nsec; | |
942 | ||
943 | if (!printk_time) | |
944 | return 0; | |
945 | ||
35dac27c RD |
946 | rem_nsec = do_div(ts, 1000000000); |
947 | ||
084681d1 | 948 | if (!buf) |
35dac27c | 949 | return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts); |
084681d1 | 950 | |
084681d1 KS |
951 | return sprintf(buf, "[%5lu.%06lu] ", |
952 | (unsigned long)ts, rem_nsec / 1000); | |
953 | } | |
954 | ||
62e32ac3 | 955 | static size_t print_prefix(const struct printk_log *msg, bool syslog, char *buf) |
649e6ee3 | 956 | { |
3ce9a7c0 | 957 | size_t len = 0; |
43a73a50 | 958 | unsigned int prefix = (msg->facility << 3) | msg->level; |
649e6ee3 | 959 | |
3ce9a7c0 KS |
960 | if (syslog) { |
961 | if (buf) { | |
43a73a50 | 962 | len += sprintf(buf, "<%u>", prefix); |
3ce9a7c0 KS |
963 | } else { |
964 | len += 3; | |
43a73a50 KS |
965 | if (prefix > 999) |
966 | len += 3; | |
967 | else if (prefix > 99) | |
968 | len += 2; | |
969 | else if (prefix > 9) | |
3ce9a7c0 KS |
970 | len++; |
971 | } | |
972 | } | |
649e6ee3 | 973 | |
084681d1 | 974 | len += print_time(msg->ts_nsec, buf ? buf + len : NULL); |
3ce9a7c0 | 975 | return len; |
649e6ee3 KS |
976 | } |
977 | ||
62e32ac3 | 978 | static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev, |
5becfb1d | 979 | bool syslog, char *buf, size_t size) |
7ff9554b | 980 | { |
3ce9a7c0 KS |
981 | const char *text = log_text(msg); |
982 | size_t text_size = msg->text_len; | |
5becfb1d KS |
983 | bool prefix = true; |
984 | bool newline = true; | |
3ce9a7c0 KS |
985 | size_t len = 0; |
986 | ||
5becfb1d KS |
987 | if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) |
988 | prefix = false; | |
989 | ||
990 | if (msg->flags & LOG_CONT) { | |
991 | if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE)) | |
992 | prefix = false; | |
993 | ||
994 | if (!(msg->flags & LOG_NEWLINE)) | |
995 | newline = false; | |
996 | } | |
997 | ||
3ce9a7c0 KS |
998 | do { |
999 | const char *next = memchr(text, '\n', text_size); | |
1000 | size_t text_len; | |
1001 | ||
1002 | if (next) { | |
1003 | text_len = next - text; | |
1004 | next++; | |
1005 | text_size -= next - text; | |
1006 | } else { | |
1007 | text_len = text_size; | |
1008 | } | |
7ff9554b | 1009 | |
3ce9a7c0 KS |
1010 | if (buf) { |
1011 | if (print_prefix(msg, syslog, NULL) + | |
70498253 | 1012 | text_len + 1 >= size - len) |
3ce9a7c0 | 1013 | break; |
7ff9554b | 1014 | |
5becfb1d KS |
1015 | if (prefix) |
1016 | len += print_prefix(msg, syslog, buf + len); | |
3ce9a7c0 KS |
1017 | memcpy(buf + len, text, text_len); |
1018 | len += text_len; | |
5becfb1d KS |
1019 | if (next || newline) |
1020 | buf[len++] = '\n'; | |
3ce9a7c0 KS |
1021 | } else { |
1022 | /* SYSLOG_ACTION_* buffer size only calculation */ | |
5becfb1d KS |
1023 | if (prefix) |
1024 | len += print_prefix(msg, syslog, NULL); | |
1025 | len += text_len; | |
1026 | if (next || newline) | |
1027 | len++; | |
3ce9a7c0 | 1028 | } |
7ff9554b | 1029 | |
5becfb1d | 1030 | prefix = true; |
3ce9a7c0 KS |
1031 | text = next; |
1032 | } while (text); | |
7ff9554b | 1033 | |
7ff9554b KS |
1034 | return len; |
1035 | } | |
1036 | ||
1037 | static int syslog_print(char __user *buf, int size) | |
1038 | { | |
1039 | char *text; | |
62e32ac3 | 1040 | struct printk_log *msg; |
116e90b2 | 1041 | int len = 0; |
7ff9554b | 1042 | |
70498253 | 1043 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1044 | if (!text) |
1045 | return -ENOMEM; | |
1046 | ||
116e90b2 JB |
1047 | while (size > 0) { |
1048 | size_t n; | |
eb02dac9 | 1049 | size_t skip; |
116e90b2 JB |
1050 | |
1051 | raw_spin_lock_irq(&logbuf_lock); | |
1052 | if (syslog_seq < log_first_seq) { | |
1053 | /* messages are gone, move to first one */ | |
1054 | syslog_seq = log_first_seq; | |
1055 | syslog_idx = log_first_idx; | |
5becfb1d | 1056 | syslog_prev = 0; |
eb02dac9 | 1057 | syslog_partial = 0; |
116e90b2 JB |
1058 | } |
1059 | if (syslog_seq == log_next_seq) { | |
1060 | raw_spin_unlock_irq(&logbuf_lock); | |
1061 | break; | |
1062 | } | |
eb02dac9 KS |
1063 | |
1064 | skip = syslog_partial; | |
116e90b2 | 1065 | msg = log_from_idx(syslog_idx); |
70498253 KS |
1066 | n = msg_print_text(msg, syslog_prev, true, text, |
1067 | LOG_LINE_MAX + PREFIX_MAX); | |
eb02dac9 KS |
1068 | if (n - syslog_partial <= size) { |
1069 | /* message fits into buffer, move forward */ | |
116e90b2 JB |
1070 | syslog_idx = log_next(syslog_idx); |
1071 | syslog_seq++; | |
5becfb1d | 1072 | syslog_prev = msg->flags; |
eb02dac9 KS |
1073 | n -= syslog_partial; |
1074 | syslog_partial = 0; | |
1075 | } else if (!len){ | |
1076 | /* partial read(), remember position */ | |
1077 | n = size; | |
1078 | syslog_partial += n; | |
116e90b2 JB |
1079 | } else |
1080 | n = 0; | |
1081 | raw_spin_unlock_irq(&logbuf_lock); | |
1082 | ||
1083 | if (!n) | |
1084 | break; | |
1085 | ||
eb02dac9 | 1086 | if (copy_to_user(buf, text + skip, n)) { |
116e90b2 JB |
1087 | if (!len) |
1088 | len = -EFAULT; | |
1089 | break; | |
1090 | } | |
eb02dac9 KS |
1091 | |
1092 | len += n; | |
1093 | size -= n; | |
1094 | buf += n; | |
7ff9554b | 1095 | } |
7ff9554b KS |
1096 | |
1097 | kfree(text); | |
1098 | return len; | |
1099 | } | |
1100 | ||
1101 | static int syslog_print_all(char __user *buf, int size, bool clear) | |
1102 | { | |
1103 | char *text; | |
1104 | int len = 0; | |
1105 | ||
70498253 | 1106 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1107 | if (!text) |
1108 | return -ENOMEM; | |
1109 | ||
1110 | raw_spin_lock_irq(&logbuf_lock); | |
1111 | if (buf) { | |
1112 | u64 next_seq; | |
1113 | u64 seq; | |
1114 | u32 idx; | |
5becfb1d | 1115 | enum log_flags prev; |
7ff9554b KS |
1116 | |
1117 | if (clear_seq < log_first_seq) { | |
1118 | /* messages are gone, move to first available one */ | |
1119 | clear_seq = log_first_seq; | |
1120 | clear_idx = log_first_idx; | |
1121 | } | |
1122 | ||
1123 | /* | |
1124 | * Find first record that fits, including all following records, | |
1125 | * into the user-provided buffer for this dump. | |
e2ae715d | 1126 | */ |
7ff9554b KS |
1127 | seq = clear_seq; |
1128 | idx = clear_idx; | |
5becfb1d | 1129 | prev = 0; |
7ff9554b | 1130 | while (seq < log_next_seq) { |
62e32ac3 | 1131 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1132 | |
5becfb1d | 1133 | len += msg_print_text(msg, prev, true, NULL, 0); |
e3756477 | 1134 | prev = msg->flags; |
7ff9554b KS |
1135 | idx = log_next(idx); |
1136 | seq++; | |
1137 | } | |
e2ae715d KS |
1138 | |
1139 | /* move first record forward until length fits into the buffer */ | |
7ff9554b KS |
1140 | seq = clear_seq; |
1141 | idx = clear_idx; | |
5becfb1d | 1142 | prev = 0; |
7ff9554b | 1143 | while (len > size && seq < log_next_seq) { |
62e32ac3 | 1144 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1145 | |
5becfb1d | 1146 | len -= msg_print_text(msg, prev, true, NULL, 0); |
e3756477 | 1147 | prev = msg->flags; |
7ff9554b KS |
1148 | idx = log_next(idx); |
1149 | seq++; | |
1150 | } | |
1151 | ||
e2ae715d | 1152 | /* last message fitting into this dump */ |
7ff9554b KS |
1153 | next_seq = log_next_seq; |
1154 | ||
1155 | len = 0; | |
1156 | while (len >= 0 && seq < next_seq) { | |
62e32ac3 | 1157 | struct printk_log *msg = log_from_idx(idx); |
7ff9554b KS |
1158 | int textlen; |
1159 | ||
70498253 KS |
1160 | textlen = msg_print_text(msg, prev, true, text, |
1161 | LOG_LINE_MAX + PREFIX_MAX); | |
7ff9554b KS |
1162 | if (textlen < 0) { |
1163 | len = textlen; | |
1164 | break; | |
1165 | } | |
1166 | idx = log_next(idx); | |
1167 | seq++; | |
5becfb1d | 1168 | prev = msg->flags; |
7ff9554b KS |
1169 | |
1170 | raw_spin_unlock_irq(&logbuf_lock); | |
1171 | if (copy_to_user(buf + len, text, textlen)) | |
1172 | len = -EFAULT; | |
1173 | else | |
1174 | len += textlen; | |
1175 | raw_spin_lock_irq(&logbuf_lock); | |
1176 | ||
1177 | if (seq < log_first_seq) { | |
1178 | /* messages are gone, move to next one */ | |
1179 | seq = log_first_seq; | |
1180 | idx = log_first_idx; | |
5becfb1d | 1181 | prev = 0; |
7ff9554b KS |
1182 | } |
1183 | } | |
1184 | } | |
1185 | ||
1186 | if (clear) { | |
1187 | clear_seq = log_next_seq; | |
1188 | clear_idx = log_next_idx; | |
1189 | } | |
1190 | raw_spin_unlock_irq(&logbuf_lock); | |
1191 | ||
1192 | kfree(text); | |
1193 | return len; | |
1194 | } | |
1195 | ||
00234592 | 1196 | int do_syslog(int type, char __user *buf, int len, bool from_file) |
1da177e4 | 1197 | { |
7ff9554b KS |
1198 | bool clear = false; |
1199 | static int saved_console_loglevel = -1; | |
ee24aebf | 1200 | int error; |
1da177e4 | 1201 | |
ee24aebf LT |
1202 | error = check_syslog_permissions(type, from_file); |
1203 | if (error) | |
1204 | goto out; | |
12b3052c EP |
1205 | |
1206 | error = security_syslog(type); | |
1da177e4 LT |
1207 | if (error) |
1208 | return error; | |
1209 | ||
1210 | switch (type) { | |
d78ca3cd | 1211 | case SYSLOG_ACTION_CLOSE: /* Close log */ |
1da177e4 | 1212 | break; |
d78ca3cd | 1213 | case SYSLOG_ACTION_OPEN: /* Open log */ |
1da177e4 | 1214 | break; |
d78ca3cd | 1215 | case SYSLOG_ACTION_READ: /* Read from log */ |
1da177e4 LT |
1216 | error = -EINVAL; |
1217 | if (!buf || len < 0) | |
1218 | goto out; | |
1219 | error = 0; | |
1220 | if (!len) | |
1221 | goto out; | |
1222 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1223 | error = -EFAULT; | |
1224 | goto out; | |
1225 | } | |
40dc5651 | 1226 | error = wait_event_interruptible(log_wait, |
7ff9554b | 1227 | syslog_seq != log_next_seq); |
cb424ffe | 1228 | if (error) |
1da177e4 | 1229 | goto out; |
7ff9554b | 1230 | error = syslog_print(buf, len); |
1da177e4 | 1231 | break; |
d78ca3cd KC |
1232 | /* Read/clear last kernel messages */ |
1233 | case SYSLOG_ACTION_READ_CLEAR: | |
7ff9554b | 1234 | clear = true; |
1da177e4 | 1235 | /* FALL THRU */ |
d78ca3cd KC |
1236 | /* Read last kernel messages */ |
1237 | case SYSLOG_ACTION_READ_ALL: | |
1da177e4 LT |
1238 | error = -EINVAL; |
1239 | if (!buf || len < 0) | |
1240 | goto out; | |
1241 | error = 0; | |
1242 | if (!len) | |
1243 | goto out; | |
1244 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1245 | error = -EFAULT; | |
1246 | goto out; | |
1247 | } | |
7ff9554b | 1248 | error = syslog_print_all(buf, len, clear); |
1da177e4 | 1249 | break; |
d78ca3cd KC |
1250 | /* Clear ring buffer */ |
1251 | case SYSLOG_ACTION_CLEAR: | |
7ff9554b | 1252 | syslog_print_all(NULL, 0, true); |
4661e356 | 1253 | break; |
d78ca3cd KC |
1254 | /* Disable logging to console */ |
1255 | case SYSLOG_ACTION_CONSOLE_OFF: | |
1aaad49e FP |
1256 | if (saved_console_loglevel == -1) |
1257 | saved_console_loglevel = console_loglevel; | |
1da177e4 LT |
1258 | console_loglevel = minimum_console_loglevel; |
1259 | break; | |
d78ca3cd KC |
1260 | /* Enable logging to console */ |
1261 | case SYSLOG_ACTION_CONSOLE_ON: | |
1aaad49e FP |
1262 | if (saved_console_loglevel != -1) { |
1263 | console_loglevel = saved_console_loglevel; | |
1264 | saved_console_loglevel = -1; | |
1265 | } | |
1da177e4 | 1266 | break; |
d78ca3cd KC |
1267 | /* Set level of messages printed to console */ |
1268 | case SYSLOG_ACTION_CONSOLE_LEVEL: | |
1da177e4 LT |
1269 | error = -EINVAL; |
1270 | if (len < 1 || len > 8) | |
1271 | goto out; | |
1272 | if (len < minimum_console_loglevel) | |
1273 | len = minimum_console_loglevel; | |
1274 | console_loglevel = len; | |
1aaad49e FP |
1275 | /* Implicitly re-enable logging to console */ |
1276 | saved_console_loglevel = -1; | |
1da177e4 LT |
1277 | error = 0; |
1278 | break; | |
d78ca3cd KC |
1279 | /* Number of chars in the log buffer */ |
1280 | case SYSLOG_ACTION_SIZE_UNREAD: | |
7ff9554b KS |
1281 | raw_spin_lock_irq(&logbuf_lock); |
1282 | if (syslog_seq < log_first_seq) { | |
1283 | /* messages are gone, move to first one */ | |
1284 | syslog_seq = log_first_seq; | |
1285 | syslog_idx = log_first_idx; | |
5becfb1d | 1286 | syslog_prev = 0; |
eb02dac9 | 1287 | syslog_partial = 0; |
7ff9554b KS |
1288 | } |
1289 | if (from_file) { | |
1290 | /* | |
1291 | * Short-cut for poll(/"proc/kmsg") which simply checks | |
1292 | * for pending data, not the size; return the count of | |
1293 | * records, not the length. | |
1294 | */ | |
1295 | error = log_next_idx - syslog_idx; | |
1296 | } else { | |
5becfb1d KS |
1297 | u64 seq = syslog_seq; |
1298 | u32 idx = syslog_idx; | |
1299 | enum log_flags prev = syslog_prev; | |
7ff9554b KS |
1300 | |
1301 | error = 0; | |
7ff9554b | 1302 | while (seq < log_next_seq) { |
62e32ac3 | 1303 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1304 | |
5becfb1d | 1305 | error += msg_print_text(msg, prev, true, NULL, 0); |
7ff9554b KS |
1306 | idx = log_next(idx); |
1307 | seq++; | |
5becfb1d | 1308 | prev = msg->flags; |
7ff9554b | 1309 | } |
eb02dac9 | 1310 | error -= syslog_partial; |
7ff9554b KS |
1311 | } |
1312 | raw_spin_unlock_irq(&logbuf_lock); | |
1da177e4 | 1313 | break; |
d78ca3cd KC |
1314 | /* Size of the log buffer */ |
1315 | case SYSLOG_ACTION_SIZE_BUFFER: | |
1da177e4 LT |
1316 | error = log_buf_len; |
1317 | break; | |
1318 | default: | |
1319 | error = -EINVAL; | |
1320 | break; | |
1321 | } | |
1322 | out: | |
1323 | return error; | |
1324 | } | |
1325 | ||
1e7bfb21 | 1326 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
1da177e4 | 1327 | { |
637241a9 | 1328 | return do_syslog(type, buf, len, SYSLOG_FROM_READER); |
1da177e4 LT |
1329 | } |
1330 | ||
1da177e4 LT |
1331 | /* |
1332 | * Call the console drivers, asking them to write out | |
1333 | * log_buf[start] to log_buf[end - 1]. | |
ac751efa | 1334 | * The console_lock must be held. |
1da177e4 | 1335 | */ |
7ff9554b | 1336 | static void call_console_drivers(int level, const char *text, size_t len) |
1da177e4 | 1337 | { |
7ff9554b | 1338 | struct console *con; |
1da177e4 | 1339 | |
07c65f4d | 1340 | trace_console(text, len); |
7ff9554b KS |
1341 | |
1342 | if (level >= console_loglevel && !ignore_loglevel) | |
1343 | return; | |
1344 | if (!console_drivers) | |
1345 | return; | |
1346 | ||
1347 | for_each_console(con) { | |
1348 | if (exclusive_console && con != exclusive_console) | |
1349 | continue; | |
1350 | if (!(con->flags & CON_ENABLED)) | |
1351 | continue; | |
1352 | if (!con->write) | |
1353 | continue; | |
1354 | if (!cpu_online(smp_processor_id()) && | |
1355 | !(con->flags & CON_ANYTIME)) | |
1356 | continue; | |
1357 | con->write(con, text, len); | |
1358 | } | |
1da177e4 LT |
1359 | } |
1360 | ||
1361 | /* | |
1362 | * Zap console related locks when oopsing. Only zap at most once | |
1363 | * every 10 seconds, to leave time for slow consoles to print a | |
1364 | * full oops. | |
1365 | */ | |
1366 | static void zap_locks(void) | |
1367 | { | |
1368 | static unsigned long oops_timestamp; | |
1369 | ||
1370 | if (time_after_eq(jiffies, oops_timestamp) && | |
40dc5651 | 1371 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
1da177e4 LT |
1372 | return; |
1373 | ||
1374 | oops_timestamp = jiffies; | |
1375 | ||
94d24fc4 | 1376 | debug_locks_off(); |
1da177e4 | 1377 | /* If a crash is occurring, make sure we can't deadlock */ |
07354eb1 | 1378 | raw_spin_lock_init(&logbuf_lock); |
1da177e4 | 1379 | /* And make sure that we print immediately */ |
5b8c4f23 | 1380 | sema_init(&console_sem, 1); |
1da177e4 LT |
1381 | } |
1382 | ||
76a8ad29 ME |
1383 | /* Check if we have any console registered that can be called early in boot. */ |
1384 | static int have_callable_console(void) | |
1385 | { | |
1386 | struct console *con; | |
1387 | ||
4d091611 | 1388 | for_each_console(con) |
76a8ad29 ME |
1389 | if (con->flags & CON_ANYTIME) |
1390 | return 1; | |
1391 | ||
1392 | return 0; | |
1393 | } | |
1394 | ||
266c2e0a LT |
1395 | /* |
1396 | * Can we actually use the console at this time on this cpu? | |
1397 | * | |
1398 | * Console drivers may assume that per-cpu resources have | |
1399 | * been allocated. So unless they're explicitly marked as | |
1400 | * being able to cope (CON_ANYTIME) don't call them until | |
1401 | * this CPU is officially up. | |
1402 | */ | |
1403 | static inline int can_use_console(unsigned int cpu) | |
1404 | { | |
1405 | return cpu_online(cpu) || have_callable_console(); | |
1406 | } | |
1407 | ||
1408 | /* | |
1409 | * Try to get console ownership to actually show the kernel | |
1410 | * messages from a 'printk'. Return true (and with the | |
ac751efa | 1411 | * console_lock held, and 'console_locked' set) if it |
266c2e0a LT |
1412 | * is successful, false otherwise. |
1413 | * | |
1414 | * This gets called with the 'logbuf_lock' spinlock held and | |
1415 | * interrupts disabled. It should return with 'lockbuf_lock' | |
1416 | * released but interrupts still disabled. | |
1417 | */ | |
ac751efa | 1418 | static int console_trylock_for_printk(unsigned int cpu) |
8155c02a | 1419 | __releases(&logbuf_lock) |
266c2e0a | 1420 | { |
0b5e1c52 | 1421 | int retval = 0, wake = 0; |
266c2e0a | 1422 | |
ac751efa | 1423 | if (console_trylock()) { |
093a07e2 LT |
1424 | retval = 1; |
1425 | ||
1426 | /* | |
1427 | * If we can't use the console, we need to release | |
1428 | * the console semaphore by hand to avoid flushing | |
1429 | * the buffer. We need to hold the console semaphore | |
1430 | * in order to do this test safely. | |
1431 | */ | |
1432 | if (!can_use_console(cpu)) { | |
1433 | console_locked = 0; | |
0b5e1c52 | 1434 | wake = 1; |
093a07e2 LT |
1435 | retval = 0; |
1436 | } | |
1437 | } | |
7ff9554b | 1438 | logbuf_cpu = UINT_MAX; |
dbda92d1 | 1439 | raw_spin_unlock(&logbuf_lock); |
0b5e1c52 PZ |
1440 | if (wake) |
1441 | up(&console_sem); | |
266c2e0a LT |
1442 | return retval; |
1443 | } | |
32a76006 | 1444 | |
af91322e DY |
1445 | int printk_delay_msec __read_mostly; |
1446 | ||
1447 | static inline void printk_delay(void) | |
1448 | { | |
1449 | if (unlikely(printk_delay_msec)) { | |
1450 | int m = printk_delay_msec; | |
1451 | ||
1452 | while (m--) { | |
1453 | mdelay(1); | |
1454 | touch_nmi_watchdog(); | |
1455 | } | |
1456 | } | |
1457 | } | |
1458 | ||
084681d1 KS |
1459 | /* |
1460 | * Continuation lines are buffered, and not committed to the record buffer | |
1461 | * until the line is complete, or a race forces it. The line fragments | |
1462 | * though, are printed immediately to the consoles to ensure everything has | |
1463 | * reached the console in case of a kernel crash. | |
1464 | */ | |
1465 | static struct cont { | |
1466 | char buf[LOG_LINE_MAX]; | |
1467 | size_t len; /* length == 0 means unused buffer */ | |
1468 | size_t cons; /* bytes written to console */ | |
1469 | struct task_struct *owner; /* task of first print*/ | |
1470 | u64 ts_nsec; /* time of first print */ | |
1471 | u8 level; /* log level of first message */ | |
1472 | u8 facility; /* log level of first message */ | |
eab07260 | 1473 | enum log_flags flags; /* prefix, newline flags */ |
084681d1 KS |
1474 | bool flushed:1; /* buffer sealed and committed */ |
1475 | } cont; | |
1476 | ||
70498253 | 1477 | static void cont_flush(enum log_flags flags) |
084681d1 KS |
1478 | { |
1479 | if (cont.flushed) | |
1480 | return; | |
1481 | if (cont.len == 0) | |
1482 | return; | |
1483 | ||
eab07260 KS |
1484 | if (cont.cons) { |
1485 | /* | |
1486 | * If a fragment of this line was directly flushed to the | |
1487 | * console; wait for the console to pick up the rest of the | |
1488 | * line. LOG_NOCONS suppresses a duplicated output. | |
1489 | */ | |
1490 | log_store(cont.facility, cont.level, flags | LOG_NOCONS, | |
1491 | cont.ts_nsec, NULL, 0, cont.buf, cont.len); | |
1492 | cont.flags = flags; | |
1493 | cont.flushed = true; | |
1494 | } else { | |
1495 | /* | |
1496 | * If no fragment of this line ever reached the console, | |
1497 | * just submit it to the store and free the buffer. | |
1498 | */ | |
1499 | log_store(cont.facility, cont.level, flags, 0, | |
1500 | NULL, 0, cont.buf, cont.len); | |
1501 | cont.len = 0; | |
1502 | } | |
084681d1 KS |
1503 | } |
1504 | ||
1505 | static bool cont_add(int facility, int level, const char *text, size_t len) | |
1506 | { | |
1507 | if (cont.len && cont.flushed) | |
1508 | return false; | |
1509 | ||
1510 | if (cont.len + len > sizeof(cont.buf)) { | |
70498253 KS |
1511 | /* the line gets too long, split it up in separate records */ |
1512 | cont_flush(LOG_CONT); | |
084681d1 KS |
1513 | return false; |
1514 | } | |
1515 | ||
1516 | if (!cont.len) { | |
1517 | cont.facility = facility; | |
1518 | cont.level = level; | |
1519 | cont.owner = current; | |
1520 | cont.ts_nsec = local_clock(); | |
eab07260 | 1521 | cont.flags = 0; |
084681d1 KS |
1522 | cont.cons = 0; |
1523 | cont.flushed = false; | |
1524 | } | |
1525 | ||
1526 | memcpy(cont.buf + cont.len, text, len); | |
1527 | cont.len += len; | |
eab07260 KS |
1528 | |
1529 | if (cont.len > (sizeof(cont.buf) * 80) / 100) | |
1530 | cont_flush(LOG_CONT); | |
1531 | ||
084681d1 KS |
1532 | return true; |
1533 | } | |
1534 | ||
1535 | static size_t cont_print_text(char *text, size_t size) | |
1536 | { | |
1537 | size_t textlen = 0; | |
1538 | size_t len; | |
1539 | ||
eab07260 | 1540 | if (cont.cons == 0 && (console_prev & LOG_NEWLINE)) { |
084681d1 KS |
1541 | textlen += print_time(cont.ts_nsec, text); |
1542 | size -= textlen; | |
1543 | } | |
1544 | ||
1545 | len = cont.len - cont.cons; | |
1546 | if (len > 0) { | |
1547 | if (len+1 > size) | |
1548 | len = size-1; | |
1549 | memcpy(text + textlen, cont.buf + cont.cons, len); | |
1550 | textlen += len; | |
1551 | cont.cons = cont.len; | |
1552 | } | |
1553 | ||
1554 | if (cont.flushed) { | |
eab07260 KS |
1555 | if (cont.flags & LOG_NEWLINE) |
1556 | text[textlen++] = '\n'; | |
084681d1 KS |
1557 | /* got everything, release buffer */ |
1558 | cont.len = 0; | |
1559 | } | |
1560 | return textlen; | |
1561 | } | |
1562 | ||
7ff9554b KS |
1563 | asmlinkage int vprintk_emit(int facility, int level, |
1564 | const char *dict, size_t dictlen, | |
1565 | const char *fmt, va_list args) | |
1da177e4 | 1566 | { |
7ff9554b | 1567 | static int recursion_bug; |
7ff9554b KS |
1568 | static char textbuf[LOG_LINE_MAX]; |
1569 | char *text = textbuf; | |
c313af14 | 1570 | size_t text_len; |
5becfb1d | 1571 | enum log_flags lflags = 0; |
ac60ad74 | 1572 | unsigned long flags; |
32a76006 | 1573 | int this_cpu; |
7ff9554b | 1574 | int printed_len = 0; |
1da177e4 | 1575 | |
2fa72c8f | 1576 | boot_delay_msec(level); |
af91322e | 1577 | printk_delay(); |
bfe8df3d | 1578 | |
1da177e4 | 1579 | /* This stops the holder of console_sem just where we want him */ |
1a9a8aef | 1580 | local_irq_save(flags); |
32a76006 IM |
1581 | this_cpu = smp_processor_id(); |
1582 | ||
1583 | /* | |
1584 | * Ouch, printk recursed into itself! | |
1585 | */ | |
7ff9554b | 1586 | if (unlikely(logbuf_cpu == this_cpu)) { |
32a76006 IM |
1587 | /* |
1588 | * If a crash is occurring during printk() on this CPU, | |
1589 | * then try to get the crash message out but make sure | |
1590 | * we can't deadlock. Otherwise just return to avoid the | |
1591 | * recursion and return - but flag the recursion so that | |
1592 | * it can be printed at the next appropriate moment: | |
1593 | */ | |
94d24fc4 | 1594 | if (!oops_in_progress && !lockdep_recursing(current)) { |
3b8945e8 | 1595 | recursion_bug = 1; |
32a76006 IM |
1596 | goto out_restore_irqs; |
1597 | } | |
1598 | zap_locks(); | |
1599 | } | |
1600 | ||
a0f1ccfd | 1601 | lockdep_off(); |
07354eb1 | 1602 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 1603 | logbuf_cpu = this_cpu; |
1da177e4 | 1604 | |
3b8945e8 | 1605 | if (recursion_bug) { |
7ff9554b KS |
1606 | static const char recursion_msg[] = |
1607 | "BUG: recent printk recursion!"; | |
1608 | ||
3b8945e8 | 1609 | recursion_bug = 0; |
034633cc | 1610 | text_len = strlen(recursion_msg); |
7ff9554b | 1611 | /* emit KERN_CRIT message */ |
034633cc PM |
1612 | printed_len += log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, |
1613 | NULL, 0, recursion_msg, text_len); | |
32a76006 | 1614 | } |
1da177e4 | 1615 | |
7ff9554b KS |
1616 | /* |
1617 | * The printf needs to come first; we need the syslog | |
1618 | * prefix which might be passed-in as a parameter. | |
1619 | */ | |
c313af14 | 1620 | text_len = vscnprintf(text, sizeof(textbuf), fmt, args); |
5fd29d6c | 1621 | |
7ff9554b | 1622 | /* mark and strip a trailing newline */ |
c313af14 KS |
1623 | if (text_len && text[text_len-1] == '\n') { |
1624 | text_len--; | |
5becfb1d | 1625 | lflags |= LOG_NEWLINE; |
7ff9554b | 1626 | } |
9d90c8d9 | 1627 | |
088a52aa JP |
1628 | /* strip kernel syslog prefix and extract log level or control flags */ |
1629 | if (facility == 0) { | |
1630 | int kern_level = printk_get_level(text); | |
1631 | ||
1632 | if (kern_level) { | |
1633 | const char *end_of_header = printk_skip_level(text); | |
1634 | switch (kern_level) { | |
1635 | case '0' ... '7': | |
1636 | if (level == -1) | |
1637 | level = kern_level - '0'; | |
1638 | case 'd': /* KERN_DEFAULT */ | |
1639 | lflags |= LOG_PREFIX; | |
088a52aa | 1640 | } |
e8c42d36 PM |
1641 | /* |
1642 | * No need to check length here because vscnprintf | |
1643 | * put '\0' at the end of the string. Only valid and | |
1644 | * newly printed level is detected. | |
1645 | */ | |
088a52aa JP |
1646 | text_len -= end_of_header - text; |
1647 | text = (char *)end_of_header; | |
5fd29d6c LT |
1648 | } |
1649 | } | |
1650 | ||
c313af14 KS |
1651 | if (level == -1) |
1652 | level = default_message_loglevel; | |
9d90c8d9 | 1653 | |
5becfb1d KS |
1654 | if (dict) |
1655 | lflags |= LOG_PREFIX|LOG_NEWLINE; | |
ac60ad74 | 1656 | |
5becfb1d | 1657 | if (!(lflags & LOG_NEWLINE)) { |
084681d1 KS |
1658 | /* |
1659 | * Flush the conflicting buffer. An earlier newline was missing, | |
1660 | * or another task also prints continuation lines. | |
1661 | */ | |
5becfb1d | 1662 | if (cont.len && (lflags & LOG_PREFIX || cont.owner != current)) |
eab07260 | 1663 | cont_flush(LOG_NEWLINE); |
c313af14 | 1664 | |
084681d1 | 1665 | /* buffer line if possible, otherwise store it right away */ |
034633cc PM |
1666 | if (cont_add(facility, level, text, text_len)) |
1667 | printed_len += text_len; | |
1668 | else | |
1669 | printed_len += log_store(facility, level, | |
1670 | lflags | LOG_CONT, 0, | |
1671 | dict, dictlen, text, text_len); | |
5c5d5ca5 | 1672 | } else { |
084681d1 | 1673 | bool stored = false; |
c313af14 | 1674 | |
084681d1 | 1675 | /* |
d3620822 SR |
1676 | * If an earlier newline was missing and it was the same task, |
1677 | * either merge it with the current buffer and flush, or if | |
1678 | * there was a race with interrupts (prefix == true) then just | |
1679 | * flush it out and store this line separately. | |
1d3fa370 AK |
1680 | * If the preceding printk was from a different task and missed |
1681 | * a newline, flush and append the newline. | |
084681d1 | 1682 | */ |
1d3fa370 AK |
1683 | if (cont.len) { |
1684 | if (cont.owner == current && !(lflags & LOG_PREFIX)) | |
1685 | stored = cont_add(facility, level, text, | |
1686 | text_len); | |
eab07260 | 1687 | cont_flush(LOG_NEWLINE); |
c313af14 | 1688 | } |
084681d1 | 1689 | |
034633cc PM |
1690 | if (stored) |
1691 | printed_len += text_len; | |
1692 | else | |
1693 | printed_len += log_store(facility, level, lflags, 0, | |
1694 | dict, dictlen, text, text_len); | |
1da177e4 LT |
1695 | } |
1696 | ||
266c2e0a | 1697 | /* |
7ff9554b KS |
1698 | * Try to acquire and then immediately release the console semaphore. |
1699 | * The release will print out buffers and wake up /dev/kmsg and syslog() | |
1700 | * users. | |
266c2e0a | 1701 | * |
7ff9554b KS |
1702 | * The console_trylock_for_printk() function will release 'logbuf_lock' |
1703 | * regardless of whether it actually gets the console semaphore or not. | |
266c2e0a | 1704 | */ |
ac751efa TH |
1705 | if (console_trylock_for_printk(this_cpu)) |
1706 | console_unlock(); | |
76a8ad29 | 1707 | |
266c2e0a | 1708 | lockdep_on(); |
32a76006 | 1709 | out_restore_irqs: |
1a9a8aef | 1710 | local_irq_restore(flags); |
76a8ad29 | 1711 | |
1da177e4 LT |
1712 | return printed_len; |
1713 | } | |
7ff9554b KS |
1714 | EXPORT_SYMBOL(vprintk_emit); |
1715 | ||
1716 | asmlinkage int vprintk(const char *fmt, va_list args) | |
1717 | { | |
1718 | return vprintk_emit(0, -1, NULL, 0, fmt, args); | |
1719 | } | |
1da177e4 LT |
1720 | EXPORT_SYMBOL(vprintk); |
1721 | ||
7ff9554b KS |
1722 | asmlinkage int printk_emit(int facility, int level, |
1723 | const char *dict, size_t dictlen, | |
1724 | const char *fmt, ...) | |
1725 | { | |
1726 | va_list args; | |
1727 | int r; | |
1728 | ||
1729 | va_start(args, fmt); | |
1730 | r = vprintk_emit(facility, level, dict, dictlen, fmt, args); | |
1731 | va_end(args); | |
1732 | ||
1733 | return r; | |
1734 | } | |
1735 | EXPORT_SYMBOL(printk_emit); | |
1736 | ||
1737 | /** | |
1738 | * printk - print a kernel message | |
1739 | * @fmt: format string | |
1740 | * | |
1741 | * This is printk(). It can be called from any context. We want it to work. | |
1742 | * | |
1743 | * We try to grab the console_lock. If we succeed, it's easy - we log the | |
1744 | * output and call the console drivers. If we fail to get the semaphore, we | |
1745 | * place the output into the log buffer and return. The current holder of | |
1746 | * the console_sem will notice the new output in console_unlock(); and will | |
1747 | * send it to the consoles before releasing the lock. | |
1748 | * | |
1749 | * One effect of this deferred printing is that code which calls printk() and | |
1750 | * then changes console_loglevel may break. This is because console_loglevel | |
1751 | * is inspected when the actual printing occurs. | |
1752 | * | |
1753 | * See also: | |
1754 | * printf(3) | |
1755 | * | |
1756 | * See the vsnprintf() documentation for format string extensions over C99. | |
1757 | */ | |
722a9f92 | 1758 | asmlinkage __visible int printk(const char *fmt, ...) |
7ff9554b KS |
1759 | { |
1760 | va_list args; | |
1761 | int r; | |
1762 | ||
1763 | #ifdef CONFIG_KGDB_KDB | |
1764 | if (unlikely(kdb_trap_printk)) { | |
1765 | va_start(args, fmt); | |
1766 | r = vkdb_printf(fmt, args); | |
1767 | va_end(args); | |
1768 | return r; | |
1769 | } | |
1770 | #endif | |
1771 | va_start(args, fmt); | |
1772 | r = vprintk_emit(0, -1, NULL, 0, fmt, args); | |
1773 | va_end(args); | |
1774 | ||
1775 | return r; | |
1776 | } | |
1777 | EXPORT_SYMBOL(printk); | |
7f3a781d | 1778 | |
96efedf1 | 1779 | #else /* CONFIG_PRINTK */ |
d59745ce | 1780 | |
70498253 KS |
1781 | #define LOG_LINE_MAX 0 |
1782 | #define PREFIX_MAX 0 | |
7f3a781d | 1783 | #define LOG_LINE_MAX 0 |
96efedf1 KS |
1784 | static u64 syslog_seq; |
1785 | static u32 syslog_idx; | |
eab07260 KS |
1786 | static u64 console_seq; |
1787 | static u32 console_idx; | |
96efedf1 KS |
1788 | static enum log_flags syslog_prev; |
1789 | static u64 log_first_seq; | |
1790 | static u32 log_first_idx; | |
1791 | static u64 log_next_seq; | |
eab07260 | 1792 | static enum log_flags console_prev; |
084681d1 KS |
1793 | static struct cont { |
1794 | size_t len; | |
1795 | size_t cons; | |
1796 | u8 level; | |
1797 | bool flushed:1; | |
1798 | } cont; | |
62e32ac3 | 1799 | static struct printk_log *log_from_idx(u32 idx) { return NULL; } |
7f3a781d | 1800 | static u32 log_next(u32 idx) { return 0; } |
7f3a781d | 1801 | static void call_console_drivers(int level, const char *text, size_t len) {} |
62e32ac3 | 1802 | static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev, |
5becfb1d | 1803 | bool syslog, char *buf, size_t size) { return 0; } |
084681d1 | 1804 | static size_t cont_print_text(char *text, size_t size) { return 0; } |
d59745ce | 1805 | |
7f3a781d | 1806 | #endif /* CONFIG_PRINTK */ |
d59745ce | 1807 | |
d0380e6c TG |
1808 | #ifdef CONFIG_EARLY_PRINTK |
1809 | struct console *early_console; | |
1810 | ||
1811 | void early_vprintk(const char *fmt, va_list ap) | |
1812 | { | |
1813 | if (early_console) { | |
1814 | char buf[512]; | |
1815 | int n = vscnprintf(buf, sizeof(buf), fmt, ap); | |
1816 | ||
1817 | early_console->write(early_console, buf, n); | |
1818 | } | |
1819 | } | |
1820 | ||
722a9f92 | 1821 | asmlinkage __visible void early_printk(const char *fmt, ...) |
d0380e6c TG |
1822 | { |
1823 | va_list ap; | |
1824 | ||
1825 | va_start(ap, fmt); | |
1826 | early_vprintk(fmt, ap); | |
1827 | va_end(ap); | |
1828 | } | |
1829 | #endif | |
1830 | ||
f7511d5f ST |
1831 | static int __add_preferred_console(char *name, int idx, char *options, |
1832 | char *brl_options) | |
1833 | { | |
1834 | struct console_cmdline *c; | |
1835 | int i; | |
1836 | ||
1837 | /* | |
1838 | * See if this tty is not yet registered, and | |
1839 | * if we have a slot free. | |
1840 | */ | |
23475408 JP |
1841 | for (i = 0, c = console_cmdline; |
1842 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
1843 | i++, c++) { | |
1844 | if (strcmp(c->name, name) == 0 && c->index == idx) { | |
1845 | if (!brl_options) | |
1846 | selected_console = i; | |
1847 | return 0; | |
f7511d5f | 1848 | } |
23475408 | 1849 | } |
f7511d5f ST |
1850 | if (i == MAX_CMDLINECONSOLES) |
1851 | return -E2BIG; | |
1852 | if (!brl_options) | |
1853 | selected_console = i; | |
f7511d5f ST |
1854 | strlcpy(c->name, name, sizeof(c->name)); |
1855 | c->options = options; | |
bbeddf52 JP |
1856 | braille_set_options(c, brl_options); |
1857 | ||
f7511d5f ST |
1858 | c->index = idx; |
1859 | return 0; | |
1860 | } | |
2ea1c539 JB |
1861 | /* |
1862 | * Set up a list of consoles. Called from init/main.c | |
1863 | */ | |
1864 | static int __init console_setup(char *str) | |
1865 | { | |
eaa944af | 1866 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ |
f7511d5f | 1867 | char *s, *options, *brl_options = NULL; |
2ea1c539 JB |
1868 | int idx; |
1869 | ||
bbeddf52 JP |
1870 | if (_braille_console_setup(&str, &brl_options)) |
1871 | return 1; | |
f7511d5f | 1872 | |
2ea1c539 JB |
1873 | /* |
1874 | * Decode str into name, index, options. | |
1875 | */ | |
1876 | if (str[0] >= '0' && str[0] <= '9') { | |
eaa944af YL |
1877 | strcpy(buf, "ttyS"); |
1878 | strncpy(buf + 4, str, sizeof(buf) - 5); | |
2ea1c539 | 1879 | } else { |
eaa944af | 1880 | strncpy(buf, str, sizeof(buf) - 1); |
2ea1c539 | 1881 | } |
eaa944af | 1882 | buf[sizeof(buf) - 1] = 0; |
2ea1c539 JB |
1883 | if ((options = strchr(str, ',')) != NULL) |
1884 | *(options++) = 0; | |
1885 | #ifdef __sparc__ | |
1886 | if (!strcmp(str, "ttya")) | |
eaa944af | 1887 | strcpy(buf, "ttyS0"); |
2ea1c539 | 1888 | if (!strcmp(str, "ttyb")) |
eaa944af | 1889 | strcpy(buf, "ttyS1"); |
2ea1c539 | 1890 | #endif |
eaa944af | 1891 | for (s = buf; *s; s++) |
2ea1c539 JB |
1892 | if ((*s >= '0' && *s <= '9') || *s == ',') |
1893 | break; | |
1894 | idx = simple_strtoul(s, NULL, 10); | |
1895 | *s = 0; | |
1896 | ||
f7511d5f | 1897 | __add_preferred_console(buf, idx, options, brl_options); |
9e124fe1 | 1898 | console_set_on_cmdline = 1; |
2ea1c539 JB |
1899 | return 1; |
1900 | } | |
1901 | __setup("console=", console_setup); | |
1902 | ||
3c0547ba MM |
1903 | /** |
1904 | * add_preferred_console - add a device to the list of preferred consoles. | |
ddad86c2 MW |
1905 | * @name: device name |
1906 | * @idx: device index | |
1907 | * @options: options for this console | |
3c0547ba MM |
1908 | * |
1909 | * The last preferred console added will be used for kernel messages | |
1910 | * and stdin/out/err for init. Normally this is used by console_setup | |
1911 | * above to handle user-supplied console arguments; however it can also | |
1912 | * be used by arch-specific code either to override the user or more | |
1913 | * commonly to provide a default console (ie from PROM variables) when | |
1914 | * the user has not supplied one. | |
1915 | */ | |
fb445ee5 | 1916 | int add_preferred_console(char *name, int idx, char *options) |
3c0547ba | 1917 | { |
f7511d5f | 1918 | return __add_preferred_console(name, idx, options, NULL); |
3c0547ba MM |
1919 | } |
1920 | ||
b6b1d877 | 1921 | int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options) |
18a8bd94 YL |
1922 | { |
1923 | struct console_cmdline *c; | |
1924 | int i; | |
1925 | ||
23475408 JP |
1926 | for (i = 0, c = console_cmdline; |
1927 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
1928 | i++, c++) | |
1929 | if (strcmp(c->name, name) == 0 && c->index == idx) { | |
1930 | strlcpy(c->name, name_new, sizeof(c->name)); | |
1931 | c->name[sizeof(c->name) - 1] = 0; | |
1932 | c->options = options; | |
1933 | c->index = idx_new; | |
1934 | return i; | |
18a8bd94 YL |
1935 | } |
1936 | /* not found */ | |
1937 | return -1; | |
1938 | } | |
1939 | ||
2329abfa | 1940 | bool console_suspend_enabled = 1; |
8f4ce8c3 AS |
1941 | EXPORT_SYMBOL(console_suspend_enabled); |
1942 | ||
1943 | static int __init console_suspend_disable(char *str) | |
1944 | { | |
1945 | console_suspend_enabled = 0; | |
1946 | return 1; | |
1947 | } | |
1948 | __setup("no_console_suspend", console_suspend_disable); | |
134620f7 YZ |
1949 | module_param_named(console_suspend, console_suspend_enabled, |
1950 | bool, S_IRUGO | S_IWUSR); | |
1951 | MODULE_PARM_DESC(console_suspend, "suspend console during suspend" | |
1952 | " and hibernate operations"); | |
8f4ce8c3 | 1953 | |
557240b4 LT |
1954 | /** |
1955 | * suspend_console - suspend the console subsystem | |
1956 | * | |
1957 | * This disables printk() while we go into suspend states | |
1958 | */ | |
1959 | void suspend_console(void) | |
1960 | { | |
8f4ce8c3 AS |
1961 | if (!console_suspend_enabled) |
1962 | return; | |
0d63081d | 1963 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
ac751efa | 1964 | console_lock(); |
557240b4 | 1965 | console_suspended = 1; |
403f3075 | 1966 | up(&console_sem); |
72581487 | 1967 | mutex_release(&console_lock_dep_map, 1, _RET_IP_); |
557240b4 LT |
1968 | } |
1969 | ||
1970 | void resume_console(void) | |
1971 | { | |
8f4ce8c3 AS |
1972 | if (!console_suspend_enabled) |
1973 | return; | |
403f3075 | 1974 | down(&console_sem); |
72581487 | 1975 | mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_); |
557240b4 | 1976 | console_suspended = 0; |
ac751efa | 1977 | console_unlock(); |
557240b4 LT |
1978 | } |
1979 | ||
034260d6 KC |
1980 | /** |
1981 | * console_cpu_notify - print deferred console messages after CPU hotplug | |
1982 | * @self: notifier struct | |
1983 | * @action: CPU hotplug event | |
1984 | * @hcpu: unused | |
1985 | * | |
1986 | * If printk() is called from a CPU that is not online yet, the messages | |
1987 | * will be spooled but will not show up on the console. This function is | |
1988 | * called when a new CPU comes online (or fails to come up), and ensures | |
1989 | * that any such output gets printed. | |
1990 | */ | |
0db0628d | 1991 | static int console_cpu_notify(struct notifier_block *self, |
034260d6 KC |
1992 | unsigned long action, void *hcpu) |
1993 | { | |
1994 | switch (action) { | |
1995 | case CPU_ONLINE: | |
1996 | case CPU_DEAD: | |
034260d6 KC |
1997 | case CPU_DOWN_FAILED: |
1998 | case CPU_UP_CANCELED: | |
ac751efa TH |
1999 | console_lock(); |
2000 | console_unlock(); | |
034260d6 KC |
2001 | } |
2002 | return NOTIFY_OK; | |
2003 | } | |
2004 | ||
1da177e4 | 2005 | /** |
ac751efa | 2006 | * console_lock - lock the console system for exclusive use. |
1da177e4 | 2007 | * |
ac751efa | 2008 | * Acquires a lock which guarantees that the caller has |
1da177e4 LT |
2009 | * exclusive access to the console system and the console_drivers list. |
2010 | * | |
2011 | * Can sleep, returns nothing. | |
2012 | */ | |
ac751efa | 2013 | void console_lock(void) |
1da177e4 | 2014 | { |
6b898c07 DV |
2015 | might_sleep(); |
2016 | ||
1da177e4 | 2017 | down(&console_sem); |
403f3075 AH |
2018 | if (console_suspended) |
2019 | return; | |
1da177e4 LT |
2020 | console_locked = 1; |
2021 | console_may_schedule = 1; | |
daee7797 | 2022 | mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_); |
1da177e4 | 2023 | } |
ac751efa | 2024 | EXPORT_SYMBOL(console_lock); |
1da177e4 | 2025 | |
ac751efa TH |
2026 | /** |
2027 | * console_trylock - try to lock the console system for exclusive use. | |
2028 | * | |
2029 | * Tried to acquire a lock which guarantees that the caller has | |
2030 | * exclusive access to the console system and the console_drivers list. | |
2031 | * | |
2032 | * returns 1 on success, and 0 on failure to acquire the lock. | |
2033 | */ | |
2034 | int console_trylock(void) | |
1da177e4 LT |
2035 | { |
2036 | if (down_trylock(&console_sem)) | |
ac751efa | 2037 | return 0; |
403f3075 AH |
2038 | if (console_suspended) { |
2039 | up(&console_sem); | |
ac751efa | 2040 | return 0; |
403f3075 | 2041 | } |
1da177e4 LT |
2042 | console_locked = 1; |
2043 | console_may_schedule = 0; | |
daee7797 | 2044 | mutex_acquire(&console_lock_dep_map, 0, 1, _RET_IP_); |
ac751efa | 2045 | return 1; |
1da177e4 | 2046 | } |
ac751efa | 2047 | EXPORT_SYMBOL(console_trylock); |
1da177e4 LT |
2048 | |
2049 | int is_console_locked(void) | |
2050 | { | |
2051 | return console_locked; | |
2052 | } | |
1da177e4 | 2053 | |
eab07260 KS |
2054 | static void console_cont_flush(char *text, size_t size) |
2055 | { | |
2056 | unsigned long flags; | |
2057 | size_t len; | |
2058 | ||
2059 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2060 | ||
2061 | if (!cont.len) | |
2062 | goto out; | |
2063 | ||
2064 | /* | |
2065 | * We still queue earlier records, likely because the console was | |
2066 | * busy. The earlier ones need to be printed before this one, we | |
2067 | * did not flush any fragment so far, so just let it queue up. | |
2068 | */ | |
2069 | if (console_seq < log_next_seq && !cont.cons) | |
2070 | goto out; | |
2071 | ||
2072 | len = cont_print_text(text, size); | |
2073 | raw_spin_unlock(&logbuf_lock); | |
2074 | stop_critical_timings(); | |
2075 | call_console_drivers(cont.level, text, len); | |
2076 | start_critical_timings(); | |
2077 | local_irq_restore(flags); | |
2078 | return; | |
2079 | out: | |
2080 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2081 | } | |
7ff9554b | 2082 | |
1da177e4 | 2083 | /** |
ac751efa | 2084 | * console_unlock - unlock the console system |
1da177e4 | 2085 | * |
ac751efa | 2086 | * Releases the console_lock which the caller holds on the console system |
1da177e4 LT |
2087 | * and the console driver list. |
2088 | * | |
ac751efa TH |
2089 | * While the console_lock was held, console output may have been buffered |
2090 | * by printk(). If this is the case, console_unlock(); emits | |
2091 | * the output prior to releasing the lock. | |
1da177e4 | 2092 | * |
7f3a781d | 2093 | * If there is output waiting, we wake /dev/kmsg and syslog() users. |
1da177e4 | 2094 | * |
ac751efa | 2095 | * console_unlock(); may be called from any context. |
1da177e4 | 2096 | */ |
ac751efa | 2097 | void console_unlock(void) |
1da177e4 | 2098 | { |
70498253 | 2099 | static char text[LOG_LINE_MAX + PREFIX_MAX]; |
7ff9554b | 2100 | static u64 seen_seq; |
1da177e4 | 2101 | unsigned long flags; |
7ff9554b KS |
2102 | bool wake_klogd = false; |
2103 | bool retry; | |
1da177e4 | 2104 | |
557240b4 | 2105 | if (console_suspended) { |
403f3075 | 2106 | up(&console_sem); |
557240b4 LT |
2107 | return; |
2108 | } | |
78944e54 AD |
2109 | |
2110 | console_may_schedule = 0; | |
2111 | ||
084681d1 | 2112 | /* flush buffered message fragment immediately to console */ |
eab07260 | 2113 | console_cont_flush(text, sizeof(text)); |
4f2a8d3c | 2114 | again: |
7ff9554b | 2115 | for (;;) { |
62e32ac3 | 2116 | struct printk_log *msg; |
3ce9a7c0 | 2117 | size_t len; |
7ff9554b KS |
2118 | int level; |
2119 | ||
07354eb1 | 2120 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2121 | if (seen_seq != log_next_seq) { |
2122 | wake_klogd = true; | |
2123 | seen_seq = log_next_seq; | |
2124 | } | |
2125 | ||
2126 | if (console_seq < log_first_seq) { | |
2127 | /* messages are gone, move to first one */ | |
2128 | console_seq = log_first_seq; | |
2129 | console_idx = log_first_idx; | |
5becfb1d | 2130 | console_prev = 0; |
7ff9554b | 2131 | } |
084681d1 | 2132 | skip: |
7ff9554b KS |
2133 | if (console_seq == log_next_seq) |
2134 | break; | |
2135 | ||
2136 | msg = log_from_idx(console_idx); | |
084681d1 KS |
2137 | if (msg->flags & LOG_NOCONS) { |
2138 | /* | |
2139 | * Skip record we have buffered and already printed | |
2140 | * directly to the console when we received it. | |
2141 | */ | |
2142 | console_idx = log_next(console_idx); | |
2143 | console_seq++; | |
68b6507d KS |
2144 | /* |
2145 | * We will get here again when we register a new | |
2146 | * CON_PRINTBUFFER console. Clear the flag so we | |
2147 | * will properly dump everything later. | |
2148 | */ | |
2149 | msg->flags &= ~LOG_NOCONS; | |
eab07260 | 2150 | console_prev = msg->flags; |
084681d1 KS |
2151 | goto skip; |
2152 | } | |
649e6ee3 | 2153 | |
084681d1 | 2154 | level = msg->level; |
5becfb1d KS |
2155 | len = msg_print_text(msg, console_prev, false, |
2156 | text, sizeof(text)); | |
7ff9554b KS |
2157 | console_idx = log_next(console_idx); |
2158 | console_seq++; | |
5becfb1d | 2159 | console_prev = msg->flags; |
07354eb1 | 2160 | raw_spin_unlock(&logbuf_lock); |
7ff9554b | 2161 | |
81d68a96 | 2162 | stop_critical_timings(); /* don't trace print latency */ |
7ff9554b | 2163 | call_console_drivers(level, text, len); |
81d68a96 | 2164 | start_critical_timings(); |
1da177e4 LT |
2165 | local_irq_restore(flags); |
2166 | } | |
2167 | console_locked = 0; | |
daee7797 | 2168 | mutex_release(&console_lock_dep_map, 1, _RET_IP_); |
fe3d8ad3 FT |
2169 | |
2170 | /* Release the exclusive_console once it is used */ | |
2171 | if (unlikely(exclusive_console)) | |
2172 | exclusive_console = NULL; | |
2173 | ||
07354eb1 | 2174 | raw_spin_unlock(&logbuf_lock); |
4f2a8d3c | 2175 | |
0b5e1c52 | 2176 | up(&console_sem); |
4f2a8d3c PZ |
2177 | |
2178 | /* | |
2179 | * Someone could have filled up the buffer again, so re-check if there's | |
2180 | * something to flush. In case we cannot trylock the console_sem again, | |
2181 | * there's a new owner and the console_unlock() from them will do the | |
2182 | * flush, no worries. | |
2183 | */ | |
07354eb1 | 2184 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 2185 | retry = console_seq != log_next_seq; |
09dc3cf9 PZ |
2186 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
2187 | ||
4f2a8d3c PZ |
2188 | if (retry && console_trylock()) |
2189 | goto again; | |
2190 | ||
e3e8a75d KK |
2191 | if (wake_klogd) |
2192 | wake_up_klogd(); | |
1da177e4 | 2193 | } |
ac751efa | 2194 | EXPORT_SYMBOL(console_unlock); |
1da177e4 | 2195 | |
ddad86c2 MW |
2196 | /** |
2197 | * console_conditional_schedule - yield the CPU if required | |
1da177e4 LT |
2198 | * |
2199 | * If the console code is currently allowed to sleep, and | |
2200 | * if this CPU should yield the CPU to another task, do | |
2201 | * so here. | |
2202 | * | |
ac751efa | 2203 | * Must be called within console_lock();. |
1da177e4 LT |
2204 | */ |
2205 | void __sched console_conditional_schedule(void) | |
2206 | { | |
2207 | if (console_may_schedule) | |
2208 | cond_resched(); | |
2209 | } | |
2210 | EXPORT_SYMBOL(console_conditional_schedule); | |
2211 | ||
1da177e4 LT |
2212 | void console_unblank(void) |
2213 | { | |
2214 | struct console *c; | |
2215 | ||
2216 | /* | |
2217 | * console_unblank can no longer be called in interrupt context unless | |
2218 | * oops_in_progress is set to 1.. | |
2219 | */ | |
2220 | if (oops_in_progress) { | |
2221 | if (down_trylock(&console_sem) != 0) | |
2222 | return; | |
2223 | } else | |
ac751efa | 2224 | console_lock(); |
1da177e4 LT |
2225 | |
2226 | console_locked = 1; | |
2227 | console_may_schedule = 0; | |
4d091611 | 2228 | for_each_console(c) |
1da177e4 LT |
2229 | if ((c->flags & CON_ENABLED) && c->unblank) |
2230 | c->unblank(); | |
ac751efa | 2231 | console_unlock(); |
1da177e4 | 2232 | } |
1da177e4 LT |
2233 | |
2234 | /* | |
2235 | * Return the console tty driver structure and its associated index | |
2236 | */ | |
2237 | struct tty_driver *console_device(int *index) | |
2238 | { | |
2239 | struct console *c; | |
2240 | struct tty_driver *driver = NULL; | |
2241 | ||
ac751efa | 2242 | console_lock(); |
4d091611 | 2243 | for_each_console(c) { |
1da177e4 LT |
2244 | if (!c->device) |
2245 | continue; | |
2246 | driver = c->device(c, index); | |
2247 | if (driver) | |
2248 | break; | |
2249 | } | |
ac751efa | 2250 | console_unlock(); |
1da177e4 LT |
2251 | return driver; |
2252 | } | |
2253 | ||
2254 | /* | |
2255 | * Prevent further output on the passed console device so that (for example) | |
2256 | * serial drivers can disable console output before suspending a port, and can | |
2257 | * re-enable output afterwards. | |
2258 | */ | |
2259 | void console_stop(struct console *console) | |
2260 | { | |
ac751efa | 2261 | console_lock(); |
1da177e4 | 2262 | console->flags &= ~CON_ENABLED; |
ac751efa | 2263 | console_unlock(); |
1da177e4 LT |
2264 | } |
2265 | EXPORT_SYMBOL(console_stop); | |
2266 | ||
2267 | void console_start(struct console *console) | |
2268 | { | |
ac751efa | 2269 | console_lock(); |
1da177e4 | 2270 | console->flags |= CON_ENABLED; |
ac751efa | 2271 | console_unlock(); |
1da177e4 LT |
2272 | } |
2273 | EXPORT_SYMBOL(console_start); | |
2274 | ||
7bf69395 FDN |
2275 | static int __read_mostly keep_bootcon; |
2276 | ||
2277 | static int __init keep_bootcon_setup(char *str) | |
2278 | { | |
2279 | keep_bootcon = 1; | |
27083bac | 2280 | pr_info("debug: skip boot console de-registration.\n"); |
7bf69395 FDN |
2281 | |
2282 | return 0; | |
2283 | } | |
2284 | ||
2285 | early_param("keep_bootcon", keep_bootcon_setup); | |
2286 | ||
1da177e4 LT |
2287 | /* |
2288 | * The console driver calls this routine during kernel initialization | |
2289 | * to register the console printing procedure with printk() and to | |
2290 | * print any messages that were printed by the kernel before the | |
2291 | * console driver was initialized. | |
4d091611 RG |
2292 | * |
2293 | * This can happen pretty early during the boot process (because of | |
2294 | * early_printk) - sometimes before setup_arch() completes - be careful | |
2295 | * of what kernel features are used - they may not be initialised yet. | |
2296 | * | |
2297 | * There are two types of consoles - bootconsoles (early_printk) and | |
2298 | * "real" consoles (everything which is not a bootconsole) which are | |
2299 | * handled differently. | |
2300 | * - Any number of bootconsoles can be registered at any time. | |
2301 | * - As soon as a "real" console is registered, all bootconsoles | |
2302 | * will be unregistered automatically. | |
2303 | * - Once a "real" console is registered, any attempt to register a | |
2304 | * bootconsoles will be rejected | |
1da177e4 | 2305 | */ |
4d091611 | 2306 | void register_console(struct console *newcon) |
1da177e4 | 2307 | { |
40dc5651 | 2308 | int i; |
1da177e4 | 2309 | unsigned long flags; |
4d091611 | 2310 | struct console *bcon = NULL; |
23475408 | 2311 | struct console_cmdline *c; |
1da177e4 | 2312 | |
16cf48a6 AB |
2313 | if (console_drivers) |
2314 | for_each_console(bcon) | |
2315 | if (WARN(bcon == newcon, | |
2316 | "console '%s%d' already registered\n", | |
2317 | bcon->name, bcon->index)) | |
2318 | return; | |
2319 | ||
4d091611 RG |
2320 | /* |
2321 | * before we register a new CON_BOOT console, make sure we don't | |
2322 | * already have a valid console | |
2323 | */ | |
2324 | if (console_drivers && newcon->flags & CON_BOOT) { | |
2325 | /* find the last or real console */ | |
2326 | for_each_console(bcon) { | |
2327 | if (!(bcon->flags & CON_BOOT)) { | |
27083bac | 2328 | pr_info("Too late to register bootconsole %s%d\n", |
4d091611 RG |
2329 | newcon->name, newcon->index); |
2330 | return; | |
2331 | } | |
2332 | } | |
69331af7 GH |
2333 | } |
2334 | ||
4d091611 RG |
2335 | if (console_drivers && console_drivers->flags & CON_BOOT) |
2336 | bcon = console_drivers; | |
2337 | ||
2338 | if (preferred_console < 0 || bcon || !console_drivers) | |
1da177e4 LT |
2339 | preferred_console = selected_console; |
2340 | ||
4d091611 RG |
2341 | if (newcon->early_setup) |
2342 | newcon->early_setup(); | |
18a8bd94 | 2343 | |
1da177e4 LT |
2344 | /* |
2345 | * See if we want to use this console driver. If we | |
2346 | * didn't select a console we take the first one | |
2347 | * that registers here. | |
2348 | */ | |
2349 | if (preferred_console < 0) { | |
4d091611 RG |
2350 | if (newcon->index < 0) |
2351 | newcon->index = 0; | |
2352 | if (newcon->setup == NULL || | |
2353 | newcon->setup(newcon, NULL) == 0) { | |
2354 | newcon->flags |= CON_ENABLED; | |
2355 | if (newcon->device) { | |
2356 | newcon->flags |= CON_CONSDEV; | |
cd3a1b85 JK |
2357 | preferred_console = 0; |
2358 | } | |
1da177e4 LT |
2359 | } |
2360 | } | |
2361 | ||
2362 | /* | |
2363 | * See if this console matches one we selected on | |
2364 | * the command line. | |
2365 | */ | |
23475408 JP |
2366 | for (i = 0, c = console_cmdline; |
2367 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
2368 | i++, c++) { | |
2369 | if (strcmp(c->name, newcon->name) != 0) | |
1da177e4 | 2370 | continue; |
4d091611 | 2371 | if (newcon->index >= 0 && |
23475408 | 2372 | newcon->index != c->index) |
1da177e4 | 2373 | continue; |
4d091611 | 2374 | if (newcon->index < 0) |
23475408 | 2375 | newcon->index = c->index; |
bbeddf52 | 2376 | |
23475408 | 2377 | if (_braille_register_console(newcon, c)) |
f7511d5f | 2378 | return; |
bbeddf52 | 2379 | |
4d091611 RG |
2380 | if (newcon->setup && |
2381 | newcon->setup(newcon, console_cmdline[i].options) != 0) | |
1da177e4 | 2382 | break; |
4d091611 | 2383 | newcon->flags |= CON_ENABLED; |
23475408 | 2384 | newcon->index = c->index; |
ab4af03a | 2385 | if (i == selected_console) { |
4d091611 | 2386 | newcon->flags |= CON_CONSDEV; |
ab4af03a GE |
2387 | preferred_console = selected_console; |
2388 | } | |
1da177e4 LT |
2389 | break; |
2390 | } | |
2391 | ||
4d091611 | 2392 | if (!(newcon->flags & CON_ENABLED)) |
1da177e4 LT |
2393 | return; |
2394 | ||
8259cf43 RG |
2395 | /* |
2396 | * If we have a bootconsole, and are switching to a real console, | |
2397 | * don't print everything out again, since when the boot console, and | |
2398 | * the real console are the same physical device, it's annoying to | |
2399 | * see the beginning boot messages twice | |
2400 | */ | |
2401 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) | |
4d091611 | 2402 | newcon->flags &= ~CON_PRINTBUFFER; |
1da177e4 LT |
2403 | |
2404 | /* | |
2405 | * Put this console in the list - keep the | |
2406 | * preferred driver at the head of the list. | |
2407 | */ | |
ac751efa | 2408 | console_lock(); |
4d091611 RG |
2409 | if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
2410 | newcon->next = console_drivers; | |
2411 | console_drivers = newcon; | |
2412 | if (newcon->next) | |
2413 | newcon->next->flags &= ~CON_CONSDEV; | |
1da177e4 | 2414 | } else { |
4d091611 RG |
2415 | newcon->next = console_drivers->next; |
2416 | console_drivers->next = newcon; | |
1da177e4 | 2417 | } |
4d091611 | 2418 | if (newcon->flags & CON_PRINTBUFFER) { |
1da177e4 | 2419 | /* |
ac751efa | 2420 | * console_unlock(); will print out the buffered messages |
1da177e4 LT |
2421 | * for us. |
2422 | */ | |
07354eb1 | 2423 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2424 | console_seq = syslog_seq; |
2425 | console_idx = syslog_idx; | |
5becfb1d | 2426 | console_prev = syslog_prev; |
07354eb1 | 2427 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
fe3d8ad3 FT |
2428 | /* |
2429 | * We're about to replay the log buffer. Only do this to the | |
2430 | * just-registered console to avoid excessive message spam to | |
2431 | * the already-registered consoles. | |
2432 | */ | |
2433 | exclusive_console = newcon; | |
1da177e4 | 2434 | } |
ac751efa | 2435 | console_unlock(); |
fbc92a34 | 2436 | console_sysfs_notify(); |
8259cf43 RG |
2437 | |
2438 | /* | |
2439 | * By unregistering the bootconsoles after we enable the real console | |
2440 | * we get the "console xxx enabled" message on all the consoles - | |
2441 | * boot consoles, real consoles, etc - this is to ensure that end | |
2442 | * users know there might be something in the kernel's log buffer that | |
2443 | * went to the bootconsole (that they do not see on the real console) | |
2444 | */ | |
27083bac | 2445 | pr_info("%sconsole [%s%d] enabled\n", |
6b802394 KC |
2446 | (newcon->flags & CON_BOOT) ? "boot" : "" , |
2447 | newcon->name, newcon->index); | |
7bf69395 FDN |
2448 | if (bcon && |
2449 | ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && | |
2450 | !keep_bootcon) { | |
6b802394 KC |
2451 | /* We need to iterate through all boot consoles, to make |
2452 | * sure we print everything out, before we unregister them. | |
8259cf43 | 2453 | */ |
8259cf43 RG |
2454 | for_each_console(bcon) |
2455 | if (bcon->flags & CON_BOOT) | |
2456 | unregister_console(bcon); | |
8259cf43 | 2457 | } |
1da177e4 LT |
2458 | } |
2459 | EXPORT_SYMBOL(register_console); | |
2460 | ||
40dc5651 | 2461 | int unregister_console(struct console *console) |
1da177e4 | 2462 | { |
40dc5651 | 2463 | struct console *a, *b; |
bbeddf52 | 2464 | int res; |
1da177e4 | 2465 | |
27083bac | 2466 | pr_info("%sconsole [%s%d] disabled\n", |
6b802394 KC |
2467 | (console->flags & CON_BOOT) ? "boot" : "" , |
2468 | console->name, console->index); | |
2469 | ||
bbeddf52 JP |
2470 | res = _braille_unregister_console(console); |
2471 | if (res) | |
2472 | return res; | |
f7511d5f | 2473 | |
bbeddf52 | 2474 | res = 1; |
ac751efa | 2475 | console_lock(); |
1da177e4 LT |
2476 | if (console_drivers == console) { |
2477 | console_drivers=console->next; | |
2478 | res = 0; | |
e9b15b54 | 2479 | } else if (console_drivers) { |
1da177e4 LT |
2480 | for (a=console_drivers->next, b=console_drivers ; |
2481 | a; b=a, a=b->next) { | |
2482 | if (a == console) { | |
2483 | b->next = a->next; | |
2484 | res = 0; | |
2485 | break; | |
40dc5651 | 2486 | } |
1da177e4 LT |
2487 | } |
2488 | } | |
40dc5651 | 2489 | |
69331af7 | 2490 | /* |
ab4af03a GE |
2491 | * If this isn't the last console and it has CON_CONSDEV set, we |
2492 | * need to set it on the next preferred console. | |
1da177e4 | 2493 | */ |
69331af7 | 2494 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
ab4af03a | 2495 | console_drivers->flags |= CON_CONSDEV; |
1da177e4 | 2496 | |
7fa21dd8 | 2497 | console->flags &= ~CON_ENABLED; |
ac751efa | 2498 | console_unlock(); |
fbc92a34 | 2499 | console_sysfs_notify(); |
1da177e4 LT |
2500 | return res; |
2501 | } | |
2502 | EXPORT_SYMBOL(unregister_console); | |
d59745ce | 2503 | |
034260d6 | 2504 | static int __init printk_late_init(void) |
0c5564bd | 2505 | { |
4d091611 RG |
2506 | struct console *con; |
2507 | ||
2508 | for_each_console(con) { | |
4c30c6f5 | 2509 | if (!keep_bootcon && con->flags & CON_BOOT) { |
42c2c8c8 | 2510 | unregister_console(con); |
cb00e99c | 2511 | } |
0c5564bd | 2512 | } |
034260d6 | 2513 | hotcpu_notifier(console_cpu_notify, 0); |
0c5564bd RG |
2514 | return 0; |
2515 | } | |
034260d6 | 2516 | late_initcall(printk_late_init); |
0c5564bd | 2517 | |
7ef3d2fd | 2518 | #if defined CONFIG_PRINTK |
dc72c32e FW |
2519 | /* |
2520 | * Delayed printk version, for scheduler-internal messages: | |
2521 | */ | |
2522 | #define PRINTK_BUF_SIZE 512 | |
2523 | ||
2524 | #define PRINTK_PENDING_WAKEUP 0x01 | |
2525 | #define PRINTK_PENDING_SCHED 0x02 | |
2526 | ||
2527 | static DEFINE_PER_CPU(int, printk_pending); | |
2528 | static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf); | |
2529 | ||
2530 | static void wake_up_klogd_work_func(struct irq_work *irq_work) | |
2531 | { | |
2532 | int pending = __this_cpu_xchg(printk_pending, 0); | |
2533 | ||
2534 | if (pending & PRINTK_PENDING_SCHED) { | |
2535 | char *buf = __get_cpu_var(printk_sched_buf); | |
27083bac | 2536 | pr_warn("[sched_delayed] %s", buf); |
dc72c32e FW |
2537 | } |
2538 | ||
2539 | if (pending & PRINTK_PENDING_WAKEUP) | |
2540 | wake_up_interruptible(&log_wait); | |
2541 | } | |
2542 | ||
2543 | static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = { | |
2544 | .func = wake_up_klogd_work_func, | |
2545 | .flags = IRQ_WORK_LAZY, | |
2546 | }; | |
2547 | ||
2548 | void wake_up_klogd(void) | |
2549 | { | |
2550 | preempt_disable(); | |
2551 | if (waitqueue_active(&log_wait)) { | |
2552 | this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); | |
2553 | irq_work_queue(&__get_cpu_var(wake_up_klogd_work)); | |
2554 | } | |
2555 | preempt_enable(); | |
2556 | } | |
717115e1 | 2557 | |
600e1458 PZ |
2558 | int printk_sched(const char *fmt, ...) |
2559 | { | |
2560 | unsigned long flags; | |
2561 | va_list args; | |
2562 | char *buf; | |
2563 | int r; | |
2564 | ||
2565 | local_irq_save(flags); | |
2566 | buf = __get_cpu_var(printk_sched_buf); | |
2567 | ||
2568 | va_start(args, fmt); | |
2569 | r = vsnprintf(buf, PRINTK_BUF_SIZE, fmt, args); | |
2570 | va_end(args); | |
2571 | ||
2572 | __this_cpu_or(printk_pending, PRINTK_PENDING_SCHED); | |
74876a98 | 2573 | irq_work_queue(&__get_cpu_var(wake_up_klogd_work)); |
600e1458 PZ |
2574 | local_irq_restore(flags); |
2575 | ||
2576 | return r; | |
2577 | } | |
2578 | ||
1da177e4 LT |
2579 | /* |
2580 | * printk rate limiting, lifted from the networking subsystem. | |
2581 | * | |
641de9d8 UKK |
2582 | * This enforces a rate limit: not more than 10 kernel messages |
2583 | * every 5s to make a denial-of-service attack impossible. | |
1da177e4 | 2584 | */ |
641de9d8 UKK |
2585 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
2586 | ||
5c828713 | 2587 | int __printk_ratelimit(const char *func) |
1da177e4 | 2588 | { |
5c828713 | 2589 | return ___ratelimit(&printk_ratelimit_state, func); |
1da177e4 | 2590 | } |
5c828713 | 2591 | EXPORT_SYMBOL(__printk_ratelimit); |
f46c4833 AM |
2592 | |
2593 | /** | |
2594 | * printk_timed_ratelimit - caller-controlled printk ratelimiting | |
2595 | * @caller_jiffies: pointer to caller's state | |
2596 | * @interval_msecs: minimum interval between prints | |
2597 | * | |
2598 | * printk_timed_ratelimit() returns true if more than @interval_msecs | |
2599 | * milliseconds have elapsed since the last time printk_timed_ratelimit() | |
2600 | * returned true. | |
2601 | */ | |
2602 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, | |
2603 | unsigned int interval_msecs) | |
2604 | { | |
f2d28a2e GK |
2605 | if (*caller_jiffies == 0 |
2606 | || !time_in_range(jiffies, *caller_jiffies, | |
2607 | *caller_jiffies | |
2608 | + msecs_to_jiffies(interval_msecs))) { | |
2609 | *caller_jiffies = jiffies; | |
f46c4833 AM |
2610 | return true; |
2611 | } | |
2612 | return false; | |
2613 | } | |
2614 | EXPORT_SYMBOL(printk_timed_ratelimit); | |
456b565c SK |
2615 | |
2616 | static DEFINE_SPINLOCK(dump_list_lock); | |
2617 | static LIST_HEAD(dump_list); | |
2618 | ||
2619 | /** | |
2620 | * kmsg_dump_register - register a kernel log dumper. | |
6485536b | 2621 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2622 | * |
2623 | * Adds a kernel log dumper to the system. The dump callback in the | |
2624 | * structure will be called when the kernel oopses or panics and must be | |
2625 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. | |
2626 | */ | |
2627 | int kmsg_dump_register(struct kmsg_dumper *dumper) | |
2628 | { | |
2629 | unsigned long flags; | |
2630 | int err = -EBUSY; | |
2631 | ||
2632 | /* The dump callback needs to be set */ | |
2633 | if (!dumper->dump) | |
2634 | return -EINVAL; | |
2635 | ||
2636 | spin_lock_irqsave(&dump_list_lock, flags); | |
2637 | /* Don't allow registering multiple times */ | |
2638 | if (!dumper->registered) { | |
2639 | dumper->registered = 1; | |
fb842b00 | 2640 | list_add_tail_rcu(&dumper->list, &dump_list); |
456b565c SK |
2641 | err = 0; |
2642 | } | |
2643 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
2644 | ||
2645 | return err; | |
2646 | } | |
2647 | EXPORT_SYMBOL_GPL(kmsg_dump_register); | |
2648 | ||
2649 | /** | |
2650 | * kmsg_dump_unregister - unregister a kmsg dumper. | |
6485536b | 2651 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2652 | * |
2653 | * Removes a dump device from the system. Returns zero on success and | |
2654 | * %-EINVAL otherwise. | |
2655 | */ | |
2656 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) | |
2657 | { | |
2658 | unsigned long flags; | |
2659 | int err = -EINVAL; | |
2660 | ||
2661 | spin_lock_irqsave(&dump_list_lock, flags); | |
2662 | if (dumper->registered) { | |
2663 | dumper->registered = 0; | |
fb842b00 | 2664 | list_del_rcu(&dumper->list); |
456b565c SK |
2665 | err = 0; |
2666 | } | |
2667 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
fb842b00 | 2668 | synchronize_rcu(); |
456b565c SK |
2669 | |
2670 | return err; | |
2671 | } | |
2672 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); | |
2673 | ||
7ff9554b KS |
2674 | static bool always_kmsg_dump; |
2675 | module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); | |
2676 | ||
456b565c SK |
2677 | /** |
2678 | * kmsg_dump - dump kernel log to kernel message dumpers. | |
2679 | * @reason: the reason (oops, panic etc) for dumping | |
2680 | * | |
e2ae715d KS |
2681 | * Call each of the registered dumper's dump() callback, which can |
2682 | * retrieve the kmsg records with kmsg_dump_get_line() or | |
2683 | * kmsg_dump_get_buffer(). | |
456b565c SK |
2684 | */ |
2685 | void kmsg_dump(enum kmsg_dump_reason reason) | |
2686 | { | |
456b565c | 2687 | struct kmsg_dumper *dumper; |
456b565c SK |
2688 | unsigned long flags; |
2689 | ||
c22ab332 MG |
2690 | if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) |
2691 | return; | |
2692 | ||
e2ae715d KS |
2693 | rcu_read_lock(); |
2694 | list_for_each_entry_rcu(dumper, &dump_list, list) { | |
2695 | if (dumper->max_reason && reason > dumper->max_reason) | |
2696 | continue; | |
2697 | ||
2698 | /* initialize iterator with data about the stored records */ | |
2699 | dumper->active = true; | |
2700 | ||
2701 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2702 | dumper->cur_seq = clear_seq; | |
2703 | dumper->cur_idx = clear_idx; | |
2704 | dumper->next_seq = log_next_seq; | |
2705 | dumper->next_idx = log_next_idx; | |
2706 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2707 | ||
2708 | /* invoke dumper which will iterate over records */ | |
2709 | dumper->dump(dumper, reason); | |
2710 | ||
2711 | /* reset iterator */ | |
2712 | dumper->active = false; | |
2713 | } | |
2714 | rcu_read_unlock(); | |
2715 | } | |
2716 | ||
2717 | /** | |
533827c9 | 2718 | * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) |
e2ae715d KS |
2719 | * @dumper: registered kmsg dumper |
2720 | * @syslog: include the "<4>" prefixes | |
2721 | * @line: buffer to copy the line to | |
2722 | * @size: maximum size of the buffer | |
2723 | * @len: length of line placed into buffer | |
2724 | * | |
2725 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2726 | * record, and copy one record into the provided buffer. | |
2727 | * | |
2728 | * Consecutive calls will return the next available record moving | |
2729 | * towards the end of the buffer with the youngest messages. | |
2730 | * | |
2731 | * A return value of FALSE indicates that there are no more records to | |
2732 | * read. | |
533827c9 AV |
2733 | * |
2734 | * The function is similar to kmsg_dump_get_line(), but grabs no locks. | |
e2ae715d | 2735 | */ |
533827c9 AV |
2736 | bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, |
2737 | char *line, size_t size, size_t *len) | |
e2ae715d | 2738 | { |
62e32ac3 | 2739 | struct printk_log *msg; |
e2ae715d KS |
2740 | size_t l = 0; |
2741 | bool ret = false; | |
2742 | ||
2743 | if (!dumper->active) | |
2744 | goto out; | |
7ff9554b | 2745 | |
e2ae715d KS |
2746 | if (dumper->cur_seq < log_first_seq) { |
2747 | /* messages are gone, move to first available one */ | |
2748 | dumper->cur_seq = log_first_seq; | |
2749 | dumper->cur_idx = log_first_idx; | |
2750 | } | |
456b565c | 2751 | |
e2ae715d | 2752 | /* last entry */ |
533827c9 | 2753 | if (dumper->cur_seq >= log_next_seq) |
e2ae715d | 2754 | goto out; |
456b565c | 2755 | |
e2ae715d | 2756 | msg = log_from_idx(dumper->cur_idx); |
5becfb1d | 2757 | l = msg_print_text(msg, 0, syslog, line, size); |
e2ae715d KS |
2758 | |
2759 | dumper->cur_idx = log_next(dumper->cur_idx); | |
2760 | dumper->cur_seq++; | |
2761 | ret = true; | |
e2ae715d KS |
2762 | out: |
2763 | if (len) | |
2764 | *len = l; | |
2765 | return ret; | |
2766 | } | |
533827c9 AV |
2767 | |
2768 | /** | |
2769 | * kmsg_dump_get_line - retrieve one kmsg log line | |
2770 | * @dumper: registered kmsg dumper | |
2771 | * @syslog: include the "<4>" prefixes | |
2772 | * @line: buffer to copy the line to | |
2773 | * @size: maximum size of the buffer | |
2774 | * @len: length of line placed into buffer | |
2775 | * | |
2776 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2777 | * record, and copy one record into the provided buffer. | |
2778 | * | |
2779 | * Consecutive calls will return the next available record moving | |
2780 | * towards the end of the buffer with the youngest messages. | |
2781 | * | |
2782 | * A return value of FALSE indicates that there are no more records to | |
2783 | * read. | |
2784 | */ | |
2785 | bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, | |
2786 | char *line, size_t size, size_t *len) | |
2787 | { | |
2788 | unsigned long flags; | |
2789 | bool ret; | |
2790 | ||
2791 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2792 | ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len); | |
2793 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2794 | ||
2795 | return ret; | |
2796 | } | |
e2ae715d KS |
2797 | EXPORT_SYMBOL_GPL(kmsg_dump_get_line); |
2798 | ||
2799 | /** | |
2800 | * kmsg_dump_get_buffer - copy kmsg log lines | |
2801 | * @dumper: registered kmsg dumper | |
2802 | * @syslog: include the "<4>" prefixes | |
4f0f4af5 | 2803 | * @buf: buffer to copy the line to |
e2ae715d KS |
2804 | * @size: maximum size of the buffer |
2805 | * @len: length of line placed into buffer | |
2806 | * | |
2807 | * Start at the end of the kmsg buffer and fill the provided buffer | |
2808 | * with as many of the the *youngest* kmsg records that fit into it. | |
2809 | * If the buffer is large enough, all available kmsg records will be | |
2810 | * copied with a single call. | |
2811 | * | |
2812 | * Consecutive calls will fill the buffer with the next block of | |
2813 | * available older records, not including the earlier retrieved ones. | |
2814 | * | |
2815 | * A return value of FALSE indicates that there are no more records to | |
2816 | * read. | |
2817 | */ | |
2818 | bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, | |
2819 | char *buf, size_t size, size_t *len) | |
2820 | { | |
2821 | unsigned long flags; | |
2822 | u64 seq; | |
2823 | u32 idx; | |
2824 | u64 next_seq; | |
2825 | u32 next_idx; | |
5becfb1d | 2826 | enum log_flags prev; |
e2ae715d KS |
2827 | size_t l = 0; |
2828 | bool ret = false; | |
2829 | ||
2830 | if (!dumper->active) | |
2831 | goto out; | |
2832 | ||
2833 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2834 | if (dumper->cur_seq < log_first_seq) { | |
2835 | /* messages are gone, move to first available one */ | |
2836 | dumper->cur_seq = log_first_seq; | |
2837 | dumper->cur_idx = log_first_idx; | |
2838 | } | |
2839 | ||
2840 | /* last entry */ | |
2841 | if (dumper->cur_seq >= dumper->next_seq) { | |
2842 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2843 | goto out; | |
2844 | } | |
2845 | ||
2846 | /* calculate length of entire buffer */ | |
2847 | seq = dumper->cur_seq; | |
2848 | idx = dumper->cur_idx; | |
5becfb1d | 2849 | prev = 0; |
e2ae715d | 2850 | while (seq < dumper->next_seq) { |
62e32ac3 | 2851 | struct printk_log *msg = log_from_idx(idx); |
e2ae715d | 2852 | |
5becfb1d | 2853 | l += msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
2854 | idx = log_next(idx); |
2855 | seq++; | |
5becfb1d | 2856 | prev = msg->flags; |
e2ae715d KS |
2857 | } |
2858 | ||
2859 | /* move first record forward until length fits into the buffer */ | |
2860 | seq = dumper->cur_seq; | |
2861 | idx = dumper->cur_idx; | |
5becfb1d | 2862 | prev = 0; |
e2ae715d | 2863 | while (l > size && seq < dumper->next_seq) { |
62e32ac3 | 2864 | struct printk_log *msg = log_from_idx(idx); |
456b565c | 2865 | |
5becfb1d | 2866 | l -= msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
2867 | idx = log_next(idx); |
2868 | seq++; | |
5becfb1d | 2869 | prev = msg->flags; |
456b565c | 2870 | } |
e2ae715d KS |
2871 | |
2872 | /* last message in next interation */ | |
2873 | next_seq = seq; | |
2874 | next_idx = idx; | |
2875 | ||
2876 | l = 0; | |
2877 | while (seq < dumper->next_seq) { | |
62e32ac3 | 2878 | struct printk_log *msg = log_from_idx(idx); |
e2ae715d | 2879 | |
5becfb1d | 2880 | l += msg_print_text(msg, prev, syslog, buf + l, size - l); |
e2ae715d KS |
2881 | idx = log_next(idx); |
2882 | seq++; | |
5becfb1d | 2883 | prev = msg->flags; |
e2ae715d KS |
2884 | } |
2885 | ||
2886 | dumper->next_seq = next_seq; | |
2887 | dumper->next_idx = next_idx; | |
2888 | ret = true; | |
7ff9554b | 2889 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
e2ae715d KS |
2890 | out: |
2891 | if (len) | |
2892 | *len = l; | |
2893 | return ret; | |
2894 | } | |
2895 | EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); | |
456b565c | 2896 | |
533827c9 AV |
2897 | /** |
2898 | * kmsg_dump_rewind_nolock - reset the interator (unlocked version) | |
2899 | * @dumper: registered kmsg dumper | |
2900 | * | |
2901 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
2902 | * kmsg_dump_get_buffer() can be called again and used multiple | |
2903 | * times within the same dumper.dump() callback. | |
2904 | * | |
2905 | * The function is similar to kmsg_dump_rewind(), but grabs no locks. | |
2906 | */ | |
2907 | void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) | |
2908 | { | |
2909 | dumper->cur_seq = clear_seq; | |
2910 | dumper->cur_idx = clear_idx; | |
2911 | dumper->next_seq = log_next_seq; | |
2912 | dumper->next_idx = log_next_idx; | |
2913 | } | |
2914 | ||
e2ae715d KS |
2915 | /** |
2916 | * kmsg_dump_rewind - reset the interator | |
2917 | * @dumper: registered kmsg dumper | |
2918 | * | |
2919 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
2920 | * kmsg_dump_get_buffer() can be called again and used multiple | |
2921 | * times within the same dumper.dump() callback. | |
2922 | */ | |
2923 | void kmsg_dump_rewind(struct kmsg_dumper *dumper) | |
2924 | { | |
2925 | unsigned long flags; | |
2926 | ||
2927 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
533827c9 | 2928 | kmsg_dump_rewind_nolock(dumper); |
e2ae715d | 2929 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
456b565c | 2930 | } |
e2ae715d | 2931 | EXPORT_SYMBOL_GPL(kmsg_dump_rewind); |
196779b9 | 2932 | |
98e5e1bf TH |
2933 | static char dump_stack_arch_desc_str[128]; |
2934 | ||
2935 | /** | |
2936 | * dump_stack_set_arch_desc - set arch-specific str to show with task dumps | |
2937 | * @fmt: printf-style format string | |
2938 | * @...: arguments for the format string | |
2939 | * | |
2940 | * The configured string will be printed right after utsname during task | |
2941 | * dumps. Usually used to add arch-specific system identifiers. If an | |
2942 | * arch wants to make use of such an ID string, it should initialize this | |
2943 | * as soon as possible during boot. | |
2944 | */ | |
2945 | void __init dump_stack_set_arch_desc(const char *fmt, ...) | |
2946 | { | |
2947 | va_list args; | |
2948 | ||
2949 | va_start(args, fmt); | |
2950 | vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), | |
2951 | fmt, args); | |
2952 | va_end(args); | |
2953 | } | |
2954 | ||
196779b9 TH |
2955 | /** |
2956 | * dump_stack_print_info - print generic debug info for dump_stack() | |
2957 | * @log_lvl: log level | |
2958 | * | |
2959 | * Arch-specific dump_stack() implementations can use this function to | |
2960 | * print out the same debug information as the generic dump_stack(). | |
2961 | */ | |
2962 | void dump_stack_print_info(const char *log_lvl) | |
2963 | { | |
2964 | printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n", | |
2965 | log_lvl, raw_smp_processor_id(), current->pid, current->comm, | |
2966 | print_tainted(), init_utsname()->release, | |
2967 | (int)strcspn(init_utsname()->version, " "), | |
2968 | init_utsname()->version); | |
98e5e1bf TH |
2969 | |
2970 | if (dump_stack_arch_desc_str[0] != '\0') | |
2971 | printk("%sHardware name: %s\n", | |
2972 | log_lvl, dump_stack_arch_desc_str); | |
3d1cb205 TH |
2973 | |
2974 | print_worker_info(log_lvl, current); | |
196779b9 TH |
2975 | } |
2976 | ||
a43cb95d TH |
2977 | /** |
2978 | * show_regs_print_info - print generic debug info for show_regs() | |
2979 | * @log_lvl: log level | |
2980 | * | |
2981 | * show_regs() implementations can use this function to print out generic | |
2982 | * debug information. | |
2983 | */ | |
2984 | void show_regs_print_info(const char *log_lvl) | |
2985 | { | |
2986 | dump_stack_print_info(log_lvl); | |
2987 | ||
2988 | printk("%stask: %p ti: %p task.ti: %p\n", | |
2989 | log_lvl, current, current_thread_info(), | |
2990 | task_thread_info(current)); | |
2991 | } | |
2992 | ||
7ef3d2fd | 2993 | #endif |