Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/kernel/printk.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * Modified to make sys_syslog() more flexible: added commands to | |
7 | * return the last 4k of kernel messages, regardless of whether | |
8 | * they've been read or not. Added option to suppress kernel printk's | |
9 | * to the console. Added hook for sending the console messages | |
10 | * elsewhere, in preparation for a serial line console (someday). | |
11 | * Ted Ts'o, 2/11/93. | |
12 | * Modified for sysctl support, 1/8/97, Chris Horn. | |
40dc5651 | 13 | * Fixed SMP synchronization, 08/08/99, Manfred Spraul |
624dffcb | 14 | * manfred@colorfullife.com |
1da177e4 | 15 | * Rewrote bits to get rid of console_lock |
e1f8e874 | 16 | * 01Mar01 Andrew Morton |
1da177e4 LT |
17 | */ |
18 | ||
19 | #include <linux/kernel.h> | |
20 | #include <linux/mm.h> | |
21 | #include <linux/tty.h> | |
22 | #include <linux/tty_driver.h> | |
1da177e4 LT |
23 | #include <linux/console.h> |
24 | #include <linux/init.h> | |
bfe8df3d RD |
25 | #include <linux/jiffies.h> |
26 | #include <linux/nmi.h> | |
1da177e4 | 27 | #include <linux/module.h> |
3b9c0410 | 28 | #include <linux/moduleparam.h> |
1da177e4 | 29 | #include <linux/interrupt.h> /* For in_interrupt() */ |
1da177e4 LT |
30 | #include <linux/delay.h> |
31 | #include <linux/smp.h> | |
32 | #include <linux/security.h> | |
33 | #include <linux/bootmem.h> | |
162a7e75 | 34 | #include <linux/memblock.h> |
1da177e4 | 35 | #include <linux/syscalls.h> |
04d491ab | 36 | #include <linux/kexec.h> |
d37d39ae | 37 | #include <linux/kdb.h> |
3fff4c42 | 38 | #include <linux/ratelimit.h> |
456b565c | 39 | #include <linux/kmsg_dump.h> |
00234592 | 40 | #include <linux/syslog.h> |
034260d6 KC |
41 | #include <linux/cpu.h> |
42 | #include <linux/notifier.h> | |
fb842b00 | 43 | #include <linux/rculist.h> |
e11fea92 | 44 | #include <linux/poll.h> |
1da177e4 LT |
45 | |
46 | #include <asm/uaccess.h> | |
47 | ||
95100358 JB |
48 | #define CREATE_TRACE_POINTS |
49 | #include <trace/events/printk.h> | |
50 | ||
076f9776 IM |
51 | /* |
52 | * Architectures can override it: | |
53 | */ | |
e17ba73b | 54 | void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...) |
076f9776 IM |
55 | { |
56 | } | |
57 | ||
1da177e4 | 58 | /* printk's without a loglevel use this.. */ |
5af5bcb8 | 59 | #define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL |
1da177e4 LT |
60 | |
61 | /* We show everything that is MORE important than this.. */ | |
62 | #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */ | |
63 | #define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */ | |
64 | ||
65 | DECLARE_WAIT_QUEUE_HEAD(log_wait); | |
66 | ||
67 | int console_printk[4] = { | |
68 | DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */ | |
69 | DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */ | |
70 | MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */ | |
71 | DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */ | |
72 | }; | |
73 | ||
1da177e4 | 74 | /* |
0bbfb7c2 | 75 | * Low level drivers may need that to know if they can schedule in |
1da177e4 LT |
76 | * their unblank() callback or not. So let's export it. |
77 | */ | |
78 | int oops_in_progress; | |
79 | EXPORT_SYMBOL(oops_in_progress); | |
80 | ||
81 | /* | |
82 | * console_sem protects the console_drivers list, and also | |
83 | * provides serialisation for access to the entire console | |
84 | * driver system. | |
85 | */ | |
5b8c4f23 | 86 | static DEFINE_SEMAPHORE(console_sem); |
1da177e4 | 87 | struct console *console_drivers; |
a29d1cfe IM |
88 | EXPORT_SYMBOL_GPL(console_drivers); |
89 | ||
1da177e4 LT |
90 | /* |
91 | * This is used for debugging the mess that is the VT code by | |
92 | * keeping track if we have the console semaphore held. It's | |
93 | * definitely not the perfect debug tool (we don't know if _WE_ | |
94 | * hold it are racing, but it helps tracking those weird code | |
95 | * path in the console code where we end up in places I want | |
96 | * locked without the console sempahore held | |
97 | */ | |
557240b4 | 98 | static int console_locked, console_suspended; |
1da177e4 | 99 | |
fe3d8ad3 FT |
100 | /* |
101 | * If exclusive_console is non-NULL then only this console is to be printed to. | |
102 | */ | |
103 | static struct console *exclusive_console; | |
104 | ||
1da177e4 LT |
105 | /* |
106 | * Array of consoles built from command line options (console=) | |
107 | */ | |
108 | struct console_cmdline | |
109 | { | |
110 | char name[8]; /* Name of the driver */ | |
111 | int index; /* Minor dev. to use */ | |
112 | char *options; /* Options for the driver */ | |
f7511d5f ST |
113 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
114 | char *brl_options; /* Options for braille driver */ | |
115 | #endif | |
1da177e4 LT |
116 | }; |
117 | ||
118 | #define MAX_CMDLINECONSOLES 8 | |
119 | ||
120 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; | |
121 | static int selected_console = -1; | |
122 | static int preferred_console = -1; | |
9e124fe1 MA |
123 | int console_set_on_cmdline; |
124 | EXPORT_SYMBOL(console_set_on_cmdline); | |
1da177e4 LT |
125 | |
126 | /* Flag: console code may call schedule() */ | |
127 | static int console_may_schedule; | |
128 | ||
7ff9554b KS |
129 | /* |
130 | * The printk log buffer consists of a chain of concatenated variable | |
131 | * length records. Every record starts with a record header, containing | |
132 | * the overall length of the record. | |
133 | * | |
134 | * The heads to the first and last entry in the buffer, as well as the | |
135 | * sequence numbers of these both entries are maintained when messages | |
136 | * are stored.. | |
137 | * | |
138 | * If the heads indicate available messages, the length in the header | |
139 | * tells the start next message. A length == 0 for the next message | |
140 | * indicates a wrap-around to the beginning of the buffer. | |
141 | * | |
142 | * Every record carries the monotonic timestamp in microseconds, as well as | |
143 | * the standard userspace syslog level and syslog facility. The usual | |
144 | * kernel messages use LOG_KERN; userspace-injected messages always carry | |
145 | * a matching syslog facility, by default LOG_USER. The origin of every | |
146 | * message can be reliably determined that way. | |
147 | * | |
148 | * The human readable log message directly follows the message header. The | |
149 | * length of the message text is stored in the header, the stored message | |
150 | * is not terminated. | |
151 | * | |
e11fea92 KS |
152 | * Optionally, a message can carry a dictionary of properties (key/value pairs), |
153 | * to provide userspace with a machine-readable message context. | |
154 | * | |
155 | * Examples for well-defined, commonly used property names are: | |
156 | * DEVICE=b12:8 device identifier | |
157 | * b12:8 block dev_t | |
158 | * c127:3 char dev_t | |
159 | * n8 netdev ifindex | |
160 | * +sound:card0 subsystem:devname | |
161 | * SUBSYSTEM=pci driver-core subsystem name | |
162 | * | |
163 | * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value | |
164 | * follows directly after a '=' character. Every property is terminated by | |
165 | * a '\0' character. The last property is not terminated. | |
166 | * | |
167 | * Example of a message structure: | |
168 | * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec | |
169 | * 0008 34 00 record is 52 bytes long | |
170 | * 000a 0b 00 text is 11 bytes long | |
171 | * 000c 1f 00 dictionary is 23 bytes long | |
172 | * 000e 03 00 LOG_KERN (facility) LOG_ERR (level) | |
173 | * 0010 69 74 27 73 20 61 20 6c "it's a l" | |
174 | * 69 6e 65 "ine" | |
175 | * 001b 44 45 56 49 43 "DEVIC" | |
176 | * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D" | |
177 | * 52 49 56 45 52 3d 62 75 "RIVER=bu" | |
178 | * 67 "g" | |
179 | * 0032 00 00 00 padding to next message header | |
180 | * | |
181 | * The 'struct log' buffer header must never be directly exported to | |
182 | * userspace, it is a kernel-private implementation detail that might | |
183 | * need to be changed in the future, when the requirements change. | |
184 | * | |
185 | * /dev/kmsg exports the structured data in the following line format: | |
186 | * "level,sequnum,timestamp;<message text>\n" | |
187 | * | |
188 | * The optional key/value pairs are attached as continuation lines starting | |
189 | * with a space character and terminated by a newline. All possible | |
190 | * non-prinatable characters are escaped in the "\xff" notation. | |
191 | * | |
192 | * Users of the export format should ignore possible additional values | |
193 | * separated by ',', and find the message after the ';' character. | |
7ff9554b KS |
194 | */ |
195 | ||
084681d1 | 196 | enum log_flags { |
5becfb1d KS |
197 | LOG_NOCONS = 1, /* already flushed, do not print to console */ |
198 | LOG_NEWLINE = 2, /* text ended with a newline */ | |
199 | LOG_PREFIX = 4, /* text started with a prefix */ | |
200 | LOG_CONT = 8, /* text is a fragment of a continuation line */ | |
084681d1 KS |
201 | }; |
202 | ||
7ff9554b KS |
203 | struct log { |
204 | u64 ts_nsec; /* timestamp in nanoseconds */ | |
205 | u16 len; /* length of entire record */ | |
206 | u16 text_len; /* length of text buffer */ | |
207 | u16 dict_len; /* length of dictionary buffer */ | |
084681d1 KS |
208 | u8 facility; /* syslog facility */ |
209 | u8 flags:5; /* internal record flags */ | |
210 | u8 level:3; /* syslog level */ | |
7ff9554b KS |
211 | }; |
212 | ||
213 | /* | |
214 | * The logbuf_lock protects kmsg buffer, indices, counters. It is also | |
215 | * used in interesting ways to provide interlocking in console_unlock(); | |
216 | */ | |
217 | static DEFINE_RAW_SPINLOCK(logbuf_lock); | |
d59745ce | 218 | |
7f3a781d KS |
219 | /* the next printk record to read by syslog(READ) or /proc/kmsg */ |
220 | static u64 syslog_seq; | |
221 | static u32 syslog_idx; | |
5becfb1d | 222 | static enum log_flags syslog_prev; |
eb02dac9 | 223 | static size_t syslog_partial; |
7ff9554b KS |
224 | |
225 | /* index and sequence number of the first record stored in the buffer */ | |
226 | static u64 log_first_seq; | |
227 | static u32 log_first_idx; | |
228 | ||
229 | /* index and sequence number of the next record to store in the buffer */ | |
230 | static u64 log_next_seq; | |
7f3a781d | 231 | #ifdef CONFIG_PRINTK |
7ff9554b KS |
232 | static u32 log_next_idx; |
233 | ||
234 | /* the next printk record to read after the last 'clear' command */ | |
235 | static u64 clear_seq; | |
236 | static u32 clear_idx; | |
237 | ||
7f3a781d KS |
238 | #define LOG_LINE_MAX 1024 |
239 | ||
240 | /* record buffer */ | |
6ebb017d | 241 | #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) |
f8450fca SW |
242 | #define LOG_ALIGN 4 |
243 | #else | |
6ebb017d | 244 | #define LOG_ALIGN __alignof__(struct log) |
f8450fca | 245 | #endif |
7f3a781d | 246 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
f8450fca | 247 | static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); |
7f3a781d KS |
248 | static char *log_buf = __log_buf; |
249 | static u32 log_buf_len = __LOG_BUF_LEN; | |
250 | ||
251 | /* cpu currently holding logbuf_lock */ | |
252 | static volatile unsigned int logbuf_cpu = UINT_MAX; | |
7ff9554b KS |
253 | |
254 | /* human readable text of the record */ | |
255 | static char *log_text(const struct log *msg) | |
256 | { | |
257 | return (char *)msg + sizeof(struct log); | |
258 | } | |
259 | ||
260 | /* optional key/value pair dictionary attached to the record */ | |
261 | static char *log_dict(const struct log *msg) | |
262 | { | |
263 | return (char *)msg + sizeof(struct log) + msg->text_len; | |
264 | } | |
265 | ||
266 | /* get record by index; idx must point to valid msg */ | |
267 | static struct log *log_from_idx(u32 idx) | |
268 | { | |
269 | struct log *msg = (struct log *)(log_buf + idx); | |
270 | ||
271 | /* | |
272 | * A length == 0 record is the end of buffer marker. Wrap around and | |
273 | * read the message at the start of the buffer. | |
274 | */ | |
275 | if (!msg->len) | |
276 | return (struct log *)log_buf; | |
277 | return msg; | |
278 | } | |
279 | ||
280 | /* get next record; idx must point to valid msg */ | |
281 | static u32 log_next(u32 idx) | |
282 | { | |
283 | struct log *msg = (struct log *)(log_buf + idx); | |
284 | ||
285 | /* length == 0 indicates the end of the buffer; wrap */ | |
286 | /* | |
287 | * A length == 0 record is the end of buffer marker. Wrap around and | |
288 | * read the message at the start of the buffer as *this* one, and | |
289 | * return the one after that. | |
290 | */ | |
291 | if (!msg->len) { | |
292 | msg = (struct log *)log_buf; | |
293 | return msg->len; | |
294 | } | |
295 | return idx + msg->len; | |
296 | } | |
297 | ||
7ff9554b KS |
298 | /* insert record into the buffer, discard old ones, update heads */ |
299 | static void log_store(int facility, int level, | |
084681d1 | 300 | enum log_flags flags, u64 ts_nsec, |
7ff9554b KS |
301 | const char *dict, u16 dict_len, |
302 | const char *text, u16 text_len) | |
303 | { | |
304 | struct log *msg; | |
305 | u32 size, pad_len; | |
306 | ||
307 | /* number of '\0' padding bytes to next message */ | |
308 | size = sizeof(struct log) + text_len + dict_len; | |
309 | pad_len = (-size) & (LOG_ALIGN - 1); | |
310 | size += pad_len; | |
311 | ||
312 | while (log_first_seq < log_next_seq) { | |
313 | u32 free; | |
314 | ||
315 | if (log_next_idx > log_first_idx) | |
316 | free = max(log_buf_len - log_next_idx, log_first_idx); | |
317 | else | |
318 | free = log_first_idx - log_next_idx; | |
319 | ||
320 | if (free > size + sizeof(struct log)) | |
321 | break; | |
322 | ||
323 | /* drop old messages until we have enough contiuous space */ | |
324 | log_first_idx = log_next(log_first_idx); | |
325 | log_first_seq++; | |
326 | } | |
327 | ||
328 | if (log_next_idx + size + sizeof(struct log) >= log_buf_len) { | |
329 | /* | |
330 | * This message + an additional empty header does not fit | |
331 | * at the end of the buffer. Add an empty header with len == 0 | |
332 | * to signify a wrap around. | |
333 | */ | |
334 | memset(log_buf + log_next_idx, 0, sizeof(struct log)); | |
335 | log_next_idx = 0; | |
336 | } | |
337 | ||
338 | /* fill message */ | |
339 | msg = (struct log *)(log_buf + log_next_idx); | |
340 | memcpy(log_text(msg), text, text_len); | |
341 | msg->text_len = text_len; | |
342 | memcpy(log_dict(msg), dict, dict_len); | |
343 | msg->dict_len = dict_len; | |
084681d1 KS |
344 | msg->facility = facility; |
345 | msg->level = level & 7; | |
346 | msg->flags = flags & 0x1f; | |
347 | if (ts_nsec > 0) | |
348 | msg->ts_nsec = ts_nsec; | |
349 | else | |
350 | msg->ts_nsec = local_clock(); | |
7ff9554b KS |
351 | memset(log_dict(msg) + dict_len, 0, pad_len); |
352 | msg->len = sizeof(struct log) + text_len + dict_len + pad_len; | |
353 | ||
354 | /* insert message */ | |
355 | log_next_idx += msg->len; | |
356 | log_next_seq++; | |
357 | } | |
d59745ce | 358 | |
e11fea92 KS |
359 | /* /dev/kmsg - userspace message inject/listen interface */ |
360 | struct devkmsg_user { | |
361 | u64 seq; | |
362 | u32 idx; | |
363 | struct mutex lock; | |
364 | char buf[8192]; | |
365 | }; | |
366 | ||
367 | static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv, | |
368 | unsigned long count, loff_t pos) | |
369 | { | |
370 | char *buf, *line; | |
371 | int i; | |
372 | int level = default_message_loglevel; | |
373 | int facility = 1; /* LOG_USER */ | |
374 | size_t len = iov_length(iv, count); | |
375 | ssize_t ret = len; | |
376 | ||
377 | if (len > LOG_LINE_MAX) | |
378 | return -EINVAL; | |
379 | buf = kmalloc(len+1, GFP_KERNEL); | |
380 | if (buf == NULL) | |
381 | return -ENOMEM; | |
382 | ||
383 | line = buf; | |
384 | for (i = 0; i < count; i++) { | |
385 | if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) | |
386 | goto out; | |
387 | line += iv[i].iov_len; | |
388 | } | |
389 | ||
390 | /* | |
391 | * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace | |
392 | * the decimal value represents 32bit, the lower 3 bit are the log | |
393 | * level, the rest are the log facility. | |
394 | * | |
395 | * If no prefix or no userspace facility is specified, we | |
396 | * enforce LOG_USER, to be able to reliably distinguish | |
397 | * kernel-generated messages from userspace-injected ones. | |
398 | */ | |
399 | line = buf; | |
400 | if (line[0] == '<') { | |
401 | char *endp = NULL; | |
402 | ||
403 | i = simple_strtoul(line+1, &endp, 10); | |
404 | if (endp && endp[0] == '>') { | |
405 | level = i & 7; | |
406 | if (i >> 3) | |
407 | facility = i >> 3; | |
408 | endp++; | |
409 | len -= endp - line; | |
410 | line = endp; | |
411 | } | |
412 | } | |
413 | line[len] = '\0'; | |
414 | ||
415 | printk_emit(facility, level, NULL, 0, "%s", line); | |
416 | out: | |
417 | kfree(buf); | |
418 | return ret; | |
419 | } | |
420 | ||
421 | static ssize_t devkmsg_read(struct file *file, char __user *buf, | |
422 | size_t count, loff_t *ppos) | |
423 | { | |
424 | struct devkmsg_user *user = file->private_data; | |
425 | struct log *msg; | |
5fc32490 | 426 | u64 ts_usec; |
e11fea92 KS |
427 | size_t i; |
428 | size_t len; | |
429 | ssize_t ret; | |
430 | ||
431 | if (!user) | |
432 | return -EBADF; | |
433 | ||
4a77a5a0 YL |
434 | ret = mutex_lock_interruptible(&user->lock); |
435 | if (ret) | |
436 | return ret; | |
5c53d819 | 437 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
438 | while (user->seq == log_next_seq) { |
439 | if (file->f_flags & O_NONBLOCK) { | |
440 | ret = -EAGAIN; | |
5c53d819 | 441 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
442 | goto out; |
443 | } | |
444 | ||
5c53d819 | 445 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
446 | ret = wait_event_interruptible(log_wait, |
447 | user->seq != log_next_seq); | |
448 | if (ret) | |
449 | goto out; | |
5c53d819 | 450 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
451 | } |
452 | ||
453 | if (user->seq < log_first_seq) { | |
454 | /* our last seen message is gone, return error and reset */ | |
455 | user->idx = log_first_idx; | |
456 | user->seq = log_first_seq; | |
457 | ret = -EPIPE; | |
5c53d819 | 458 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
459 | goto out; |
460 | } | |
461 | ||
462 | msg = log_from_idx(user->idx); | |
5fc32490 KS |
463 | ts_usec = msg->ts_nsec; |
464 | do_div(ts_usec, 1000); | |
e11fea92 | 465 | len = sprintf(user->buf, "%u,%llu,%llu;", |
084681d1 | 466 | (msg->facility << 3) | msg->level, user->seq, ts_usec); |
e11fea92 KS |
467 | |
468 | /* escape non-printable characters */ | |
469 | for (i = 0; i < msg->text_len; i++) { | |
3ce9a7c0 | 470 | unsigned char c = log_text(msg)[i]; |
e11fea92 | 471 | |
e3f5a5f2 | 472 | if (c < ' ' || c >= 127 || c == '\\') |
e11fea92 KS |
473 | len += sprintf(user->buf + len, "\\x%02x", c); |
474 | else | |
475 | user->buf[len++] = c; | |
476 | } | |
477 | user->buf[len++] = '\n'; | |
478 | ||
479 | if (msg->dict_len) { | |
480 | bool line = true; | |
481 | ||
482 | for (i = 0; i < msg->dict_len; i++) { | |
3ce9a7c0 | 483 | unsigned char c = log_dict(msg)[i]; |
e11fea92 KS |
484 | |
485 | if (line) { | |
486 | user->buf[len++] = ' '; | |
487 | line = false; | |
488 | } | |
489 | ||
490 | if (c == '\0') { | |
491 | user->buf[len++] = '\n'; | |
492 | line = true; | |
493 | continue; | |
494 | } | |
495 | ||
e3f5a5f2 | 496 | if (c < ' ' || c >= 127 || c == '\\') { |
e11fea92 KS |
497 | len += sprintf(user->buf + len, "\\x%02x", c); |
498 | continue; | |
499 | } | |
500 | ||
501 | user->buf[len++] = c; | |
502 | } | |
503 | user->buf[len++] = '\n'; | |
504 | } | |
505 | ||
506 | user->idx = log_next(user->idx); | |
507 | user->seq++; | |
5c53d819 | 508 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
509 | |
510 | if (len > count) { | |
511 | ret = -EINVAL; | |
512 | goto out; | |
513 | } | |
514 | ||
515 | if (copy_to_user(buf, user->buf, len)) { | |
516 | ret = -EFAULT; | |
517 | goto out; | |
518 | } | |
519 | ret = len; | |
520 | out: | |
521 | mutex_unlock(&user->lock); | |
522 | return ret; | |
523 | } | |
524 | ||
525 | static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) | |
526 | { | |
527 | struct devkmsg_user *user = file->private_data; | |
528 | loff_t ret = 0; | |
529 | ||
530 | if (!user) | |
531 | return -EBADF; | |
532 | if (offset) | |
533 | return -ESPIPE; | |
534 | ||
5c53d819 | 535 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
536 | switch (whence) { |
537 | case SEEK_SET: | |
538 | /* the first record */ | |
539 | user->idx = log_first_idx; | |
540 | user->seq = log_first_seq; | |
541 | break; | |
542 | case SEEK_DATA: | |
543 | /* | |
544 | * The first record after the last SYSLOG_ACTION_CLEAR, | |
545 | * like issued by 'dmesg -c'. Reading /dev/kmsg itself | |
546 | * changes no global state, and does not clear anything. | |
547 | */ | |
548 | user->idx = clear_idx; | |
549 | user->seq = clear_seq; | |
550 | break; | |
551 | case SEEK_END: | |
552 | /* after the last record */ | |
553 | user->idx = log_next_idx; | |
554 | user->seq = log_next_seq; | |
555 | break; | |
556 | default: | |
557 | ret = -EINVAL; | |
558 | } | |
5c53d819 | 559 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
560 | return ret; |
561 | } | |
562 | ||
563 | static unsigned int devkmsg_poll(struct file *file, poll_table *wait) | |
564 | { | |
565 | struct devkmsg_user *user = file->private_data; | |
566 | int ret = 0; | |
567 | ||
568 | if (!user) | |
569 | return POLLERR|POLLNVAL; | |
570 | ||
571 | poll_wait(file, &log_wait, wait); | |
572 | ||
5c53d819 | 573 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
574 | if (user->seq < log_next_seq) { |
575 | /* return error when data has vanished underneath us */ | |
576 | if (user->seq < log_first_seq) | |
577 | ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI; | |
578 | ret = POLLIN|POLLRDNORM; | |
579 | } | |
5c53d819 | 580 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
581 | |
582 | return ret; | |
583 | } | |
584 | ||
585 | static int devkmsg_open(struct inode *inode, struct file *file) | |
586 | { | |
587 | struct devkmsg_user *user; | |
588 | int err; | |
589 | ||
590 | /* write-only does not need any file context */ | |
591 | if ((file->f_flags & O_ACCMODE) == O_WRONLY) | |
592 | return 0; | |
593 | ||
594 | err = security_syslog(SYSLOG_ACTION_READ_ALL); | |
595 | if (err) | |
596 | return err; | |
597 | ||
598 | user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL); | |
599 | if (!user) | |
600 | return -ENOMEM; | |
601 | ||
602 | mutex_init(&user->lock); | |
603 | ||
5c53d819 | 604 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
605 | user->idx = log_first_idx; |
606 | user->seq = log_first_seq; | |
5c53d819 | 607 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
608 | |
609 | file->private_data = user; | |
610 | return 0; | |
611 | } | |
612 | ||
613 | static int devkmsg_release(struct inode *inode, struct file *file) | |
614 | { | |
615 | struct devkmsg_user *user = file->private_data; | |
616 | ||
617 | if (!user) | |
618 | return 0; | |
619 | ||
620 | mutex_destroy(&user->lock); | |
621 | kfree(user); | |
622 | return 0; | |
623 | } | |
624 | ||
625 | const struct file_operations kmsg_fops = { | |
626 | .open = devkmsg_open, | |
627 | .read = devkmsg_read, | |
628 | .aio_write = devkmsg_writev, | |
629 | .llseek = devkmsg_llseek, | |
630 | .poll = devkmsg_poll, | |
631 | .release = devkmsg_release, | |
632 | }; | |
633 | ||
04d491ab NH |
634 | #ifdef CONFIG_KEXEC |
635 | /* | |
636 | * This appends the listed symbols to /proc/vmcoreinfo | |
637 | * | |
638 | * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to | |
639 | * obtain access to symbols that are otherwise very difficult to locate. These | |
640 | * symbols are specifically used so that utilities can access and extract the | |
641 | * dmesg log from a vmcore file after a crash. | |
642 | */ | |
643 | void log_buf_kexec_setup(void) | |
644 | { | |
645 | VMCOREINFO_SYMBOL(log_buf); | |
04d491ab | 646 | VMCOREINFO_SYMBOL(log_buf_len); |
7ff9554b KS |
647 | VMCOREINFO_SYMBOL(log_first_idx); |
648 | VMCOREINFO_SYMBOL(log_next_idx); | |
04d491ab NH |
649 | } |
650 | #endif | |
651 | ||
162a7e75 MT |
652 | /* requested log_buf_len from kernel cmdline */ |
653 | static unsigned long __initdata new_log_buf_len; | |
654 | ||
655 | /* save requested log_buf_len since it's too early to process it */ | |
1da177e4 LT |
656 | static int __init log_buf_len_setup(char *str) |
657 | { | |
eed4a2ab | 658 | unsigned size = memparse(str, &str); |
1da177e4 LT |
659 | |
660 | if (size) | |
661 | size = roundup_pow_of_two(size); | |
162a7e75 MT |
662 | if (size > log_buf_len) |
663 | new_log_buf_len = size; | |
664 | ||
665 | return 0; | |
1da177e4 | 666 | } |
162a7e75 MT |
667 | early_param("log_buf_len", log_buf_len_setup); |
668 | ||
669 | void __init setup_log_buf(int early) | |
670 | { | |
671 | unsigned long flags; | |
162a7e75 MT |
672 | char *new_log_buf; |
673 | int free; | |
674 | ||
675 | if (!new_log_buf_len) | |
676 | return; | |
1da177e4 | 677 | |
162a7e75 MT |
678 | if (early) { |
679 | unsigned long mem; | |
680 | ||
681 | mem = memblock_alloc(new_log_buf_len, PAGE_SIZE); | |
1f5026a7 | 682 | if (!mem) |
162a7e75 MT |
683 | return; |
684 | new_log_buf = __va(mem); | |
685 | } else { | |
686 | new_log_buf = alloc_bootmem_nopanic(new_log_buf_len); | |
687 | } | |
688 | ||
689 | if (unlikely(!new_log_buf)) { | |
690 | pr_err("log_buf_len: %ld bytes not available\n", | |
691 | new_log_buf_len); | |
692 | return; | |
693 | } | |
694 | ||
07354eb1 | 695 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
162a7e75 MT |
696 | log_buf_len = new_log_buf_len; |
697 | log_buf = new_log_buf; | |
698 | new_log_buf_len = 0; | |
7ff9554b KS |
699 | free = __LOG_BUF_LEN - log_next_idx; |
700 | memcpy(log_buf, __log_buf, __LOG_BUF_LEN); | |
07354eb1 | 701 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
162a7e75 MT |
702 | |
703 | pr_info("log_buf_len: %d\n", log_buf_len); | |
704 | pr_info("early log buf free: %d(%d%%)\n", | |
705 | free, (free * 100) / __LOG_BUF_LEN); | |
706 | } | |
1da177e4 | 707 | |
bfe8df3d RD |
708 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
709 | ||
674dff65 | 710 | static int boot_delay; /* msecs delay after each printk during bootup */ |
3a3b6ed2 | 711 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
bfe8df3d RD |
712 | |
713 | static int __init boot_delay_setup(char *str) | |
714 | { | |
715 | unsigned long lpj; | |
bfe8df3d RD |
716 | |
717 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ | |
718 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; | |
719 | ||
720 | get_option(&str, &boot_delay); | |
721 | if (boot_delay > 10 * 1000) | |
722 | boot_delay = 0; | |
723 | ||
3a3b6ed2 DY |
724 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
725 | "HZ: %d, loops_per_msec: %llu\n", | |
726 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); | |
bfe8df3d RD |
727 | return 1; |
728 | } | |
729 | __setup("boot_delay=", boot_delay_setup); | |
730 | ||
731 | static void boot_delay_msec(void) | |
732 | { | |
733 | unsigned long long k; | |
734 | unsigned long timeout; | |
735 | ||
736 | if (boot_delay == 0 || system_state != SYSTEM_BOOTING) | |
737 | return; | |
738 | ||
3a3b6ed2 | 739 | k = (unsigned long long)loops_per_msec * boot_delay; |
bfe8df3d RD |
740 | |
741 | timeout = jiffies + msecs_to_jiffies(boot_delay); | |
742 | while (k) { | |
743 | k--; | |
744 | cpu_relax(); | |
745 | /* | |
746 | * use (volatile) jiffies to prevent | |
747 | * compiler reduction; loop termination via jiffies | |
748 | * is secondary and may or may not happen. | |
749 | */ | |
750 | if (time_after(jiffies, timeout)) | |
751 | break; | |
752 | touch_nmi_watchdog(); | |
753 | } | |
754 | } | |
755 | #else | |
756 | static inline void boot_delay_msec(void) | |
757 | { | |
758 | } | |
759 | #endif | |
760 | ||
eaf06b24 DR |
761 | #ifdef CONFIG_SECURITY_DMESG_RESTRICT |
762 | int dmesg_restrict = 1; | |
763 | #else | |
764 | int dmesg_restrict; | |
765 | #endif | |
766 | ||
ee24aebf LT |
767 | static int syslog_action_restricted(int type) |
768 | { | |
769 | if (dmesg_restrict) | |
770 | return 1; | |
771 | /* Unless restricted, we allow "read all" and "get buffer size" for everybody */ | |
772 | return type != SYSLOG_ACTION_READ_ALL && type != SYSLOG_ACTION_SIZE_BUFFER; | |
773 | } | |
774 | ||
775 | static int check_syslog_permissions(int type, bool from_file) | |
776 | { | |
777 | /* | |
778 | * If this is from /proc/kmsg and we've already opened it, then we've | |
779 | * already done the capabilities checks at open time. | |
780 | */ | |
781 | if (from_file && type != SYSLOG_ACTION_OPEN) | |
782 | return 0; | |
783 | ||
784 | if (syslog_action_restricted(type)) { | |
785 | if (capable(CAP_SYSLOG)) | |
786 | return 0; | |
787 | /* For historical reasons, accept CAP_SYS_ADMIN too, with a warning */ | |
788 | if (capable(CAP_SYS_ADMIN)) { | |
f2c0d026 JN |
789 | printk_once(KERN_WARNING "%s (%d): " |
790 | "Attempt to access syslog with CAP_SYS_ADMIN " | |
791 | "but no CAP_SYSLOG (deprecated).\n", | |
792 | current->comm, task_pid_nr(current)); | |
ee24aebf LT |
793 | return 0; |
794 | } | |
795 | return -EPERM; | |
796 | } | |
797 | return 0; | |
798 | } | |
799 | ||
7ff9554b KS |
800 | #if defined(CONFIG_PRINTK_TIME) |
801 | static bool printk_time = 1; | |
802 | #else | |
803 | static bool printk_time; | |
804 | #endif | |
805 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); | |
806 | ||
084681d1 KS |
807 | static size_t print_time(u64 ts, char *buf) |
808 | { | |
809 | unsigned long rem_nsec; | |
810 | ||
811 | if (!printk_time) | |
812 | return 0; | |
813 | ||
814 | if (!buf) | |
815 | return 15; | |
816 | ||
817 | rem_nsec = do_div(ts, 1000000000); | |
818 | return sprintf(buf, "[%5lu.%06lu] ", | |
819 | (unsigned long)ts, rem_nsec / 1000); | |
820 | } | |
821 | ||
3ce9a7c0 | 822 | static size_t print_prefix(const struct log *msg, bool syslog, char *buf) |
649e6ee3 | 823 | { |
3ce9a7c0 | 824 | size_t len = 0; |
43a73a50 | 825 | unsigned int prefix = (msg->facility << 3) | msg->level; |
649e6ee3 | 826 | |
3ce9a7c0 KS |
827 | if (syslog) { |
828 | if (buf) { | |
43a73a50 | 829 | len += sprintf(buf, "<%u>", prefix); |
3ce9a7c0 KS |
830 | } else { |
831 | len += 3; | |
43a73a50 KS |
832 | if (prefix > 999) |
833 | len += 3; | |
834 | else if (prefix > 99) | |
835 | len += 2; | |
836 | else if (prefix > 9) | |
3ce9a7c0 KS |
837 | len++; |
838 | } | |
839 | } | |
649e6ee3 | 840 | |
084681d1 | 841 | len += print_time(msg->ts_nsec, buf ? buf + len : NULL); |
3ce9a7c0 | 842 | return len; |
649e6ee3 KS |
843 | } |
844 | ||
5becfb1d KS |
845 | static size_t msg_print_text(const struct log *msg, enum log_flags prev, |
846 | bool syslog, char *buf, size_t size) | |
7ff9554b | 847 | { |
3ce9a7c0 KS |
848 | const char *text = log_text(msg); |
849 | size_t text_size = msg->text_len; | |
5becfb1d KS |
850 | bool prefix = true; |
851 | bool newline = true; | |
3ce9a7c0 KS |
852 | size_t len = 0; |
853 | ||
5becfb1d KS |
854 | if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) |
855 | prefix = false; | |
856 | ||
857 | if (msg->flags & LOG_CONT) { | |
858 | if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE)) | |
859 | prefix = false; | |
860 | ||
861 | if (!(msg->flags & LOG_NEWLINE)) | |
862 | newline = false; | |
863 | } | |
864 | ||
3ce9a7c0 KS |
865 | do { |
866 | const char *next = memchr(text, '\n', text_size); | |
867 | size_t text_len; | |
868 | ||
869 | if (next) { | |
870 | text_len = next - text; | |
871 | next++; | |
872 | text_size -= next - text; | |
873 | } else { | |
874 | text_len = text_size; | |
875 | } | |
7ff9554b | 876 | |
3ce9a7c0 KS |
877 | if (buf) { |
878 | if (print_prefix(msg, syslog, NULL) + | |
879 | text_len + 1>= size - len) | |
880 | break; | |
7ff9554b | 881 | |
5becfb1d KS |
882 | if (prefix) |
883 | len += print_prefix(msg, syslog, buf + len); | |
3ce9a7c0 KS |
884 | memcpy(buf + len, text, text_len); |
885 | len += text_len; | |
5becfb1d KS |
886 | if (next || newline) |
887 | buf[len++] = '\n'; | |
3ce9a7c0 KS |
888 | } else { |
889 | /* SYSLOG_ACTION_* buffer size only calculation */ | |
5becfb1d KS |
890 | if (prefix) |
891 | len += print_prefix(msg, syslog, NULL); | |
892 | len += text_len; | |
893 | if (next || newline) | |
894 | len++; | |
3ce9a7c0 | 895 | } |
7ff9554b | 896 | |
5becfb1d | 897 | prefix = true; |
3ce9a7c0 KS |
898 | text = next; |
899 | } while (text); | |
7ff9554b | 900 | |
7ff9554b KS |
901 | return len; |
902 | } | |
903 | ||
904 | static int syslog_print(char __user *buf, int size) | |
905 | { | |
906 | char *text; | |
3ce9a7c0 | 907 | struct log *msg; |
116e90b2 | 908 | int len = 0; |
7ff9554b KS |
909 | |
910 | text = kmalloc(LOG_LINE_MAX, GFP_KERNEL); | |
911 | if (!text) | |
912 | return -ENOMEM; | |
913 | ||
116e90b2 JB |
914 | while (size > 0) { |
915 | size_t n; | |
eb02dac9 | 916 | size_t skip; |
116e90b2 JB |
917 | |
918 | raw_spin_lock_irq(&logbuf_lock); | |
919 | if (syslog_seq < log_first_seq) { | |
920 | /* messages are gone, move to first one */ | |
921 | syslog_seq = log_first_seq; | |
922 | syslog_idx = log_first_idx; | |
5becfb1d | 923 | syslog_prev = 0; |
eb02dac9 | 924 | syslog_partial = 0; |
116e90b2 JB |
925 | } |
926 | if (syslog_seq == log_next_seq) { | |
927 | raw_spin_unlock_irq(&logbuf_lock); | |
928 | break; | |
929 | } | |
eb02dac9 KS |
930 | |
931 | skip = syslog_partial; | |
116e90b2 | 932 | msg = log_from_idx(syslog_idx); |
5becfb1d | 933 | n = msg_print_text(msg, syslog_prev, true, text, LOG_LINE_MAX); |
eb02dac9 KS |
934 | if (n - syslog_partial <= size) { |
935 | /* message fits into buffer, move forward */ | |
116e90b2 JB |
936 | syslog_idx = log_next(syslog_idx); |
937 | syslog_seq++; | |
5becfb1d | 938 | syslog_prev = msg->flags; |
eb02dac9 KS |
939 | n -= syslog_partial; |
940 | syslog_partial = 0; | |
941 | } else if (!len){ | |
942 | /* partial read(), remember position */ | |
943 | n = size; | |
944 | syslog_partial += n; | |
116e90b2 JB |
945 | } else |
946 | n = 0; | |
947 | raw_spin_unlock_irq(&logbuf_lock); | |
948 | ||
949 | if (!n) | |
950 | break; | |
951 | ||
eb02dac9 | 952 | if (copy_to_user(buf, text + skip, n)) { |
116e90b2 JB |
953 | if (!len) |
954 | len = -EFAULT; | |
955 | break; | |
956 | } | |
eb02dac9 KS |
957 | |
958 | len += n; | |
959 | size -= n; | |
960 | buf += n; | |
7ff9554b | 961 | } |
7ff9554b KS |
962 | |
963 | kfree(text); | |
964 | return len; | |
965 | } | |
966 | ||
967 | static int syslog_print_all(char __user *buf, int size, bool clear) | |
968 | { | |
969 | char *text; | |
970 | int len = 0; | |
971 | ||
972 | text = kmalloc(LOG_LINE_MAX, GFP_KERNEL); | |
973 | if (!text) | |
974 | return -ENOMEM; | |
975 | ||
976 | raw_spin_lock_irq(&logbuf_lock); | |
977 | if (buf) { | |
978 | u64 next_seq; | |
979 | u64 seq; | |
980 | u32 idx; | |
5becfb1d | 981 | enum log_flags prev; |
7ff9554b KS |
982 | |
983 | if (clear_seq < log_first_seq) { | |
984 | /* messages are gone, move to first available one */ | |
985 | clear_seq = log_first_seq; | |
986 | clear_idx = log_first_idx; | |
987 | } | |
988 | ||
989 | /* | |
990 | * Find first record that fits, including all following records, | |
991 | * into the user-provided buffer for this dump. | |
e2ae715d | 992 | */ |
7ff9554b KS |
993 | seq = clear_seq; |
994 | idx = clear_idx; | |
5becfb1d | 995 | prev = 0; |
7ff9554b | 996 | while (seq < log_next_seq) { |
3ce9a7c0 KS |
997 | struct log *msg = log_from_idx(idx); |
998 | ||
5becfb1d | 999 | len += msg_print_text(msg, prev, true, NULL, 0); |
7ff9554b KS |
1000 | idx = log_next(idx); |
1001 | seq++; | |
1002 | } | |
e2ae715d KS |
1003 | |
1004 | /* move first record forward until length fits into the buffer */ | |
7ff9554b KS |
1005 | seq = clear_seq; |
1006 | idx = clear_idx; | |
5becfb1d | 1007 | prev = 0; |
7ff9554b | 1008 | while (len > size && seq < log_next_seq) { |
3ce9a7c0 KS |
1009 | struct log *msg = log_from_idx(idx); |
1010 | ||
5becfb1d | 1011 | len -= msg_print_text(msg, prev, true, NULL, 0); |
7ff9554b KS |
1012 | idx = log_next(idx); |
1013 | seq++; | |
1014 | } | |
1015 | ||
e2ae715d | 1016 | /* last message fitting into this dump */ |
7ff9554b KS |
1017 | next_seq = log_next_seq; |
1018 | ||
1019 | len = 0; | |
5becfb1d | 1020 | prev = 0; |
7ff9554b | 1021 | while (len >= 0 && seq < next_seq) { |
3ce9a7c0 | 1022 | struct log *msg = log_from_idx(idx); |
7ff9554b KS |
1023 | int textlen; |
1024 | ||
5becfb1d | 1025 | textlen = msg_print_text(msg, prev, true, text, LOG_LINE_MAX); |
7ff9554b KS |
1026 | if (textlen < 0) { |
1027 | len = textlen; | |
1028 | break; | |
1029 | } | |
1030 | idx = log_next(idx); | |
1031 | seq++; | |
5becfb1d | 1032 | prev = msg->flags; |
7ff9554b KS |
1033 | |
1034 | raw_spin_unlock_irq(&logbuf_lock); | |
1035 | if (copy_to_user(buf + len, text, textlen)) | |
1036 | len = -EFAULT; | |
1037 | else | |
1038 | len += textlen; | |
1039 | raw_spin_lock_irq(&logbuf_lock); | |
1040 | ||
1041 | if (seq < log_first_seq) { | |
1042 | /* messages are gone, move to next one */ | |
1043 | seq = log_first_seq; | |
1044 | idx = log_first_idx; | |
5becfb1d | 1045 | prev = 0; |
7ff9554b KS |
1046 | } |
1047 | } | |
1048 | } | |
1049 | ||
1050 | if (clear) { | |
1051 | clear_seq = log_next_seq; | |
1052 | clear_idx = log_next_idx; | |
1053 | } | |
1054 | raw_spin_unlock_irq(&logbuf_lock); | |
1055 | ||
1056 | kfree(text); | |
1057 | return len; | |
1058 | } | |
1059 | ||
00234592 | 1060 | int do_syslog(int type, char __user *buf, int len, bool from_file) |
1da177e4 | 1061 | { |
7ff9554b KS |
1062 | bool clear = false; |
1063 | static int saved_console_loglevel = -1; | |
ee24aebf | 1064 | int error; |
1da177e4 | 1065 | |
ee24aebf LT |
1066 | error = check_syslog_permissions(type, from_file); |
1067 | if (error) | |
1068 | goto out; | |
12b3052c EP |
1069 | |
1070 | error = security_syslog(type); | |
1da177e4 LT |
1071 | if (error) |
1072 | return error; | |
1073 | ||
1074 | switch (type) { | |
d78ca3cd | 1075 | case SYSLOG_ACTION_CLOSE: /* Close log */ |
1da177e4 | 1076 | break; |
d78ca3cd | 1077 | case SYSLOG_ACTION_OPEN: /* Open log */ |
1da177e4 | 1078 | break; |
d78ca3cd | 1079 | case SYSLOG_ACTION_READ: /* Read from log */ |
1da177e4 LT |
1080 | error = -EINVAL; |
1081 | if (!buf || len < 0) | |
1082 | goto out; | |
1083 | error = 0; | |
1084 | if (!len) | |
1085 | goto out; | |
1086 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1087 | error = -EFAULT; | |
1088 | goto out; | |
1089 | } | |
40dc5651 | 1090 | error = wait_event_interruptible(log_wait, |
7ff9554b | 1091 | syslog_seq != log_next_seq); |
cb424ffe | 1092 | if (error) |
1da177e4 | 1093 | goto out; |
7ff9554b | 1094 | error = syslog_print(buf, len); |
1da177e4 | 1095 | break; |
d78ca3cd KC |
1096 | /* Read/clear last kernel messages */ |
1097 | case SYSLOG_ACTION_READ_CLEAR: | |
7ff9554b | 1098 | clear = true; |
1da177e4 | 1099 | /* FALL THRU */ |
d78ca3cd KC |
1100 | /* Read last kernel messages */ |
1101 | case SYSLOG_ACTION_READ_ALL: | |
1da177e4 LT |
1102 | error = -EINVAL; |
1103 | if (!buf || len < 0) | |
1104 | goto out; | |
1105 | error = 0; | |
1106 | if (!len) | |
1107 | goto out; | |
1108 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1109 | error = -EFAULT; | |
1110 | goto out; | |
1111 | } | |
7ff9554b | 1112 | error = syslog_print_all(buf, len, clear); |
1da177e4 | 1113 | break; |
d78ca3cd KC |
1114 | /* Clear ring buffer */ |
1115 | case SYSLOG_ACTION_CLEAR: | |
7ff9554b | 1116 | syslog_print_all(NULL, 0, true); |
4661e356 | 1117 | break; |
d78ca3cd KC |
1118 | /* Disable logging to console */ |
1119 | case SYSLOG_ACTION_CONSOLE_OFF: | |
1aaad49e FP |
1120 | if (saved_console_loglevel == -1) |
1121 | saved_console_loglevel = console_loglevel; | |
1da177e4 LT |
1122 | console_loglevel = minimum_console_loglevel; |
1123 | break; | |
d78ca3cd KC |
1124 | /* Enable logging to console */ |
1125 | case SYSLOG_ACTION_CONSOLE_ON: | |
1aaad49e FP |
1126 | if (saved_console_loglevel != -1) { |
1127 | console_loglevel = saved_console_loglevel; | |
1128 | saved_console_loglevel = -1; | |
1129 | } | |
1da177e4 | 1130 | break; |
d78ca3cd KC |
1131 | /* Set level of messages printed to console */ |
1132 | case SYSLOG_ACTION_CONSOLE_LEVEL: | |
1da177e4 LT |
1133 | error = -EINVAL; |
1134 | if (len < 1 || len > 8) | |
1135 | goto out; | |
1136 | if (len < minimum_console_loglevel) | |
1137 | len = minimum_console_loglevel; | |
1138 | console_loglevel = len; | |
1aaad49e FP |
1139 | /* Implicitly re-enable logging to console */ |
1140 | saved_console_loglevel = -1; | |
1da177e4 LT |
1141 | error = 0; |
1142 | break; | |
d78ca3cd KC |
1143 | /* Number of chars in the log buffer */ |
1144 | case SYSLOG_ACTION_SIZE_UNREAD: | |
7ff9554b KS |
1145 | raw_spin_lock_irq(&logbuf_lock); |
1146 | if (syslog_seq < log_first_seq) { | |
1147 | /* messages are gone, move to first one */ | |
1148 | syslog_seq = log_first_seq; | |
1149 | syslog_idx = log_first_idx; | |
5becfb1d | 1150 | syslog_prev = 0; |
eb02dac9 | 1151 | syslog_partial = 0; |
7ff9554b KS |
1152 | } |
1153 | if (from_file) { | |
1154 | /* | |
1155 | * Short-cut for poll(/"proc/kmsg") which simply checks | |
1156 | * for pending data, not the size; return the count of | |
1157 | * records, not the length. | |
1158 | */ | |
1159 | error = log_next_idx - syslog_idx; | |
1160 | } else { | |
5becfb1d KS |
1161 | u64 seq = syslog_seq; |
1162 | u32 idx = syslog_idx; | |
1163 | enum log_flags prev = syslog_prev; | |
7ff9554b KS |
1164 | |
1165 | error = 0; | |
7ff9554b | 1166 | while (seq < log_next_seq) { |
3ce9a7c0 KS |
1167 | struct log *msg = log_from_idx(idx); |
1168 | ||
5becfb1d | 1169 | error += msg_print_text(msg, prev, true, NULL, 0); |
7ff9554b KS |
1170 | idx = log_next(idx); |
1171 | seq++; | |
5becfb1d | 1172 | prev = msg->flags; |
7ff9554b | 1173 | } |
eb02dac9 | 1174 | error -= syslog_partial; |
7ff9554b KS |
1175 | } |
1176 | raw_spin_unlock_irq(&logbuf_lock); | |
1da177e4 | 1177 | break; |
d78ca3cd KC |
1178 | /* Size of the log buffer */ |
1179 | case SYSLOG_ACTION_SIZE_BUFFER: | |
1da177e4 LT |
1180 | error = log_buf_len; |
1181 | break; | |
1182 | default: | |
1183 | error = -EINVAL; | |
1184 | break; | |
1185 | } | |
1186 | out: | |
1187 | return error; | |
1188 | } | |
1189 | ||
1e7bfb21 | 1190 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
1da177e4 | 1191 | { |
00234592 | 1192 | return do_syslog(type, buf, len, SYSLOG_FROM_CALL); |
1da177e4 LT |
1193 | } |
1194 | ||
2329abfa | 1195 | static bool __read_mostly ignore_loglevel; |
79290822 | 1196 | |
99eea6a1 | 1197 | static int __init ignore_loglevel_setup(char *str) |
79290822 IM |
1198 | { |
1199 | ignore_loglevel = 1; | |
1200 | printk(KERN_INFO "debug: ignoring loglevel setting.\n"); | |
1201 | ||
c4772d99 | 1202 | return 0; |
79290822 IM |
1203 | } |
1204 | ||
c4772d99 | 1205 | early_param("ignore_loglevel", ignore_loglevel_setup); |
29d4d6df | 1206 | module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); |
0eca6b7c YZ |
1207 | MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to" |
1208 | "print all kernel messages to the console."); | |
79290822 | 1209 | |
1da177e4 LT |
1210 | /* |
1211 | * Call the console drivers, asking them to write out | |
1212 | * log_buf[start] to log_buf[end - 1]. | |
ac751efa | 1213 | * The console_lock must be held. |
1da177e4 | 1214 | */ |
7ff9554b | 1215 | static void call_console_drivers(int level, const char *text, size_t len) |
1da177e4 | 1216 | { |
7ff9554b | 1217 | struct console *con; |
1da177e4 | 1218 | |
7ff9554b KS |
1219 | trace_console(text, 0, len, len); |
1220 | ||
1221 | if (level >= console_loglevel && !ignore_loglevel) | |
1222 | return; | |
1223 | if (!console_drivers) | |
1224 | return; | |
1225 | ||
1226 | for_each_console(con) { | |
1227 | if (exclusive_console && con != exclusive_console) | |
1228 | continue; | |
1229 | if (!(con->flags & CON_ENABLED)) | |
1230 | continue; | |
1231 | if (!con->write) | |
1232 | continue; | |
1233 | if (!cpu_online(smp_processor_id()) && | |
1234 | !(con->flags & CON_ANYTIME)) | |
1235 | continue; | |
1236 | con->write(con, text, len); | |
1237 | } | |
1da177e4 LT |
1238 | } |
1239 | ||
1240 | /* | |
1241 | * Zap console related locks when oopsing. Only zap at most once | |
1242 | * every 10 seconds, to leave time for slow consoles to print a | |
1243 | * full oops. | |
1244 | */ | |
1245 | static void zap_locks(void) | |
1246 | { | |
1247 | static unsigned long oops_timestamp; | |
1248 | ||
1249 | if (time_after_eq(jiffies, oops_timestamp) && | |
40dc5651 | 1250 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
1da177e4 LT |
1251 | return; |
1252 | ||
1253 | oops_timestamp = jiffies; | |
1254 | ||
94d24fc4 | 1255 | debug_locks_off(); |
1da177e4 | 1256 | /* If a crash is occurring, make sure we can't deadlock */ |
07354eb1 | 1257 | raw_spin_lock_init(&logbuf_lock); |
1da177e4 | 1258 | /* And make sure that we print immediately */ |
5b8c4f23 | 1259 | sema_init(&console_sem, 1); |
1da177e4 LT |
1260 | } |
1261 | ||
76a8ad29 ME |
1262 | /* Check if we have any console registered that can be called early in boot. */ |
1263 | static int have_callable_console(void) | |
1264 | { | |
1265 | struct console *con; | |
1266 | ||
4d091611 | 1267 | for_each_console(con) |
76a8ad29 ME |
1268 | if (con->flags & CON_ANYTIME) |
1269 | return 1; | |
1270 | ||
1271 | return 0; | |
1272 | } | |
1273 | ||
266c2e0a LT |
1274 | /* |
1275 | * Can we actually use the console at this time on this cpu? | |
1276 | * | |
1277 | * Console drivers may assume that per-cpu resources have | |
1278 | * been allocated. So unless they're explicitly marked as | |
1279 | * being able to cope (CON_ANYTIME) don't call them until | |
1280 | * this CPU is officially up. | |
1281 | */ | |
1282 | static inline int can_use_console(unsigned int cpu) | |
1283 | { | |
1284 | return cpu_online(cpu) || have_callable_console(); | |
1285 | } | |
1286 | ||
1287 | /* | |
1288 | * Try to get console ownership to actually show the kernel | |
1289 | * messages from a 'printk'. Return true (and with the | |
ac751efa | 1290 | * console_lock held, and 'console_locked' set) if it |
266c2e0a LT |
1291 | * is successful, false otherwise. |
1292 | * | |
1293 | * This gets called with the 'logbuf_lock' spinlock held and | |
1294 | * interrupts disabled. It should return with 'lockbuf_lock' | |
1295 | * released but interrupts still disabled. | |
1296 | */ | |
ac751efa | 1297 | static int console_trylock_for_printk(unsigned int cpu) |
8155c02a | 1298 | __releases(&logbuf_lock) |
266c2e0a | 1299 | { |
0b5e1c52 | 1300 | int retval = 0, wake = 0; |
266c2e0a | 1301 | |
ac751efa | 1302 | if (console_trylock()) { |
093a07e2 LT |
1303 | retval = 1; |
1304 | ||
1305 | /* | |
1306 | * If we can't use the console, we need to release | |
1307 | * the console semaphore by hand to avoid flushing | |
1308 | * the buffer. We need to hold the console semaphore | |
1309 | * in order to do this test safely. | |
1310 | */ | |
1311 | if (!can_use_console(cpu)) { | |
1312 | console_locked = 0; | |
0b5e1c52 | 1313 | wake = 1; |
093a07e2 LT |
1314 | retval = 0; |
1315 | } | |
1316 | } | |
7ff9554b | 1317 | logbuf_cpu = UINT_MAX; |
0b5e1c52 PZ |
1318 | if (wake) |
1319 | up(&console_sem); | |
07354eb1 | 1320 | raw_spin_unlock(&logbuf_lock); |
266c2e0a LT |
1321 | return retval; |
1322 | } | |
32a76006 | 1323 | |
af91322e DY |
1324 | int printk_delay_msec __read_mostly; |
1325 | ||
1326 | static inline void printk_delay(void) | |
1327 | { | |
1328 | if (unlikely(printk_delay_msec)) { | |
1329 | int m = printk_delay_msec; | |
1330 | ||
1331 | while (m--) { | |
1332 | mdelay(1); | |
1333 | touch_nmi_watchdog(); | |
1334 | } | |
1335 | } | |
1336 | } | |
1337 | ||
084681d1 KS |
1338 | /* |
1339 | * Continuation lines are buffered, and not committed to the record buffer | |
1340 | * until the line is complete, or a race forces it. The line fragments | |
1341 | * though, are printed immediately to the consoles to ensure everything has | |
1342 | * reached the console in case of a kernel crash. | |
1343 | */ | |
1344 | static struct cont { | |
1345 | char buf[LOG_LINE_MAX]; | |
1346 | size_t len; /* length == 0 means unused buffer */ | |
1347 | size_t cons; /* bytes written to console */ | |
1348 | struct task_struct *owner; /* task of first print*/ | |
1349 | u64 ts_nsec; /* time of first print */ | |
1350 | u8 level; /* log level of first message */ | |
1351 | u8 facility; /* log level of first message */ | |
1352 | bool flushed:1; /* buffer sealed and committed */ | |
1353 | } cont; | |
1354 | ||
1355 | static void cont_flush(void) | |
1356 | { | |
1357 | if (cont.flushed) | |
1358 | return; | |
1359 | if (cont.len == 0) | |
1360 | return; | |
1361 | ||
1362 | log_store(cont.facility, cont.level, LOG_NOCONS, cont.ts_nsec, | |
1363 | NULL, 0, cont.buf, cont.len); | |
1364 | ||
1365 | cont.flushed = true; | |
1366 | } | |
1367 | ||
1368 | static bool cont_add(int facility, int level, const char *text, size_t len) | |
1369 | { | |
1370 | if (cont.len && cont.flushed) | |
1371 | return false; | |
1372 | ||
1373 | if (cont.len + len > sizeof(cont.buf)) { | |
1374 | cont_flush(); | |
1375 | return false; | |
1376 | } | |
1377 | ||
1378 | if (!cont.len) { | |
1379 | cont.facility = facility; | |
1380 | cont.level = level; | |
1381 | cont.owner = current; | |
1382 | cont.ts_nsec = local_clock(); | |
1383 | cont.cons = 0; | |
1384 | cont.flushed = false; | |
1385 | } | |
1386 | ||
1387 | memcpy(cont.buf + cont.len, text, len); | |
1388 | cont.len += len; | |
1389 | return true; | |
1390 | } | |
1391 | ||
1392 | static size_t cont_print_text(char *text, size_t size) | |
1393 | { | |
1394 | size_t textlen = 0; | |
1395 | size_t len; | |
1396 | ||
1397 | if (cont.cons == 0) { | |
1398 | textlen += print_time(cont.ts_nsec, text); | |
1399 | size -= textlen; | |
1400 | } | |
1401 | ||
1402 | len = cont.len - cont.cons; | |
1403 | if (len > 0) { | |
1404 | if (len+1 > size) | |
1405 | len = size-1; | |
1406 | memcpy(text + textlen, cont.buf + cont.cons, len); | |
1407 | textlen += len; | |
1408 | cont.cons = cont.len; | |
1409 | } | |
1410 | ||
1411 | if (cont.flushed) { | |
1412 | text[textlen++] = '\n'; | |
1413 | /* got everything, release buffer */ | |
1414 | cont.len = 0; | |
1415 | } | |
1416 | return textlen; | |
1417 | } | |
1418 | ||
7ff9554b KS |
1419 | asmlinkage int vprintk_emit(int facility, int level, |
1420 | const char *dict, size_t dictlen, | |
1421 | const char *fmt, va_list args) | |
1da177e4 | 1422 | { |
7ff9554b | 1423 | static int recursion_bug; |
7ff9554b KS |
1424 | static char textbuf[LOG_LINE_MAX]; |
1425 | char *text = textbuf; | |
c313af14 | 1426 | size_t text_len; |
5becfb1d | 1427 | enum log_flags lflags = 0; |
ac60ad74 | 1428 | unsigned long flags; |
32a76006 | 1429 | int this_cpu; |
7ff9554b | 1430 | int printed_len = 0; |
1da177e4 | 1431 | |
bfe8df3d | 1432 | boot_delay_msec(); |
af91322e | 1433 | printk_delay(); |
bfe8df3d | 1434 | |
1da177e4 | 1435 | /* This stops the holder of console_sem just where we want him */ |
1a9a8aef | 1436 | local_irq_save(flags); |
32a76006 IM |
1437 | this_cpu = smp_processor_id(); |
1438 | ||
1439 | /* | |
1440 | * Ouch, printk recursed into itself! | |
1441 | */ | |
7ff9554b | 1442 | if (unlikely(logbuf_cpu == this_cpu)) { |
32a76006 IM |
1443 | /* |
1444 | * If a crash is occurring during printk() on this CPU, | |
1445 | * then try to get the crash message out but make sure | |
1446 | * we can't deadlock. Otherwise just return to avoid the | |
1447 | * recursion and return - but flag the recursion so that | |
1448 | * it can be printed at the next appropriate moment: | |
1449 | */ | |
94d24fc4 | 1450 | if (!oops_in_progress && !lockdep_recursing(current)) { |
3b8945e8 | 1451 | recursion_bug = 1; |
32a76006 IM |
1452 | goto out_restore_irqs; |
1453 | } | |
1454 | zap_locks(); | |
1455 | } | |
1456 | ||
a0f1ccfd | 1457 | lockdep_off(); |
07354eb1 | 1458 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 1459 | logbuf_cpu = this_cpu; |
1da177e4 | 1460 | |
3b8945e8 | 1461 | if (recursion_bug) { |
7ff9554b KS |
1462 | static const char recursion_msg[] = |
1463 | "BUG: recent printk recursion!"; | |
1464 | ||
3b8945e8 | 1465 | recursion_bug = 0; |
7ff9554b KS |
1466 | printed_len += strlen(recursion_msg); |
1467 | /* emit KERN_CRIT message */ | |
5becfb1d | 1468 | log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, |
084681d1 | 1469 | NULL, 0, recursion_msg, printed_len); |
32a76006 | 1470 | } |
1da177e4 | 1471 | |
7ff9554b KS |
1472 | /* |
1473 | * The printf needs to come first; we need the syslog | |
1474 | * prefix which might be passed-in as a parameter. | |
1475 | */ | |
c313af14 | 1476 | text_len = vscnprintf(text, sizeof(textbuf), fmt, args); |
5fd29d6c | 1477 | |
7ff9554b | 1478 | /* mark and strip a trailing newline */ |
c313af14 KS |
1479 | if (text_len && text[text_len-1] == '\n') { |
1480 | text_len--; | |
5becfb1d | 1481 | lflags |= LOG_NEWLINE; |
7ff9554b | 1482 | } |
9d90c8d9 | 1483 | |
c313af14 | 1484 | /* strip syslog prefix and extract log level or control flags */ |
7ff9554b KS |
1485 | if (text[0] == '<' && text[1] && text[2] == '>') { |
1486 | switch (text[1]) { | |
1487 | case '0' ... '7': | |
1488 | if (level == -1) | |
1489 | level = text[1] - '0'; | |
7ff9554b | 1490 | case 'd': /* KERN_DEFAULT */ |
5becfb1d | 1491 | lflags |= LOG_PREFIX; |
5c5d5ca5 | 1492 | case 'c': /* KERN_CONT */ |
7ff9554b | 1493 | text += 3; |
c313af14 | 1494 | text_len -= 3; |
5fd29d6c LT |
1495 | } |
1496 | } | |
1497 | ||
c313af14 KS |
1498 | if (level == -1) |
1499 | level = default_message_loglevel; | |
9d90c8d9 | 1500 | |
5becfb1d KS |
1501 | if (dict) |
1502 | lflags |= LOG_PREFIX|LOG_NEWLINE; | |
ac60ad74 | 1503 | |
5becfb1d | 1504 | if (!(lflags & LOG_NEWLINE)) { |
084681d1 KS |
1505 | /* |
1506 | * Flush the conflicting buffer. An earlier newline was missing, | |
1507 | * or another task also prints continuation lines. | |
1508 | */ | |
5becfb1d | 1509 | if (cont.len && (lflags & LOG_PREFIX || cont.owner != current)) |
084681d1 | 1510 | cont_flush(); |
c313af14 | 1511 | |
084681d1 KS |
1512 | /* buffer line if possible, otherwise store it right away */ |
1513 | if (!cont_add(facility, level, text, text_len)) | |
5becfb1d | 1514 | log_store(facility, level, lflags | LOG_CONT, 0, |
084681d1 | 1515 | dict, dictlen, text, text_len); |
5c5d5ca5 | 1516 | } else { |
084681d1 | 1517 | bool stored = false; |
c313af14 | 1518 | |
084681d1 | 1519 | /* |
d3620822 SR |
1520 | * If an earlier newline was missing and it was the same task, |
1521 | * either merge it with the current buffer and flush, or if | |
1522 | * there was a race with interrupts (prefix == true) then just | |
1523 | * flush it out and store this line separately. | |
084681d1 | 1524 | */ |
084681d1 | 1525 | if (cont.len && cont.owner == current) { |
5becfb1d | 1526 | if (!(lflags & LOG_PREFIX)) |
d3620822 | 1527 | stored = cont_add(facility, level, text, text_len); |
084681d1 | 1528 | cont_flush(); |
c313af14 | 1529 | } |
084681d1 KS |
1530 | |
1531 | if (!stored) | |
5becfb1d | 1532 | log_store(facility, level, lflags, 0, |
084681d1 | 1533 | dict, dictlen, text, text_len); |
1da177e4 | 1534 | } |
084681d1 | 1535 | printed_len += text_len; |
1da177e4 | 1536 | |
266c2e0a | 1537 | /* |
7ff9554b KS |
1538 | * Try to acquire and then immediately release the console semaphore. |
1539 | * The release will print out buffers and wake up /dev/kmsg and syslog() | |
1540 | * users. | |
266c2e0a | 1541 | * |
7ff9554b KS |
1542 | * The console_trylock_for_printk() function will release 'logbuf_lock' |
1543 | * regardless of whether it actually gets the console semaphore or not. | |
266c2e0a | 1544 | */ |
ac751efa TH |
1545 | if (console_trylock_for_printk(this_cpu)) |
1546 | console_unlock(); | |
76a8ad29 | 1547 | |
266c2e0a | 1548 | lockdep_on(); |
32a76006 | 1549 | out_restore_irqs: |
1a9a8aef | 1550 | local_irq_restore(flags); |
76a8ad29 | 1551 | |
1da177e4 LT |
1552 | return printed_len; |
1553 | } | |
7ff9554b KS |
1554 | EXPORT_SYMBOL(vprintk_emit); |
1555 | ||
1556 | asmlinkage int vprintk(const char *fmt, va_list args) | |
1557 | { | |
1558 | return vprintk_emit(0, -1, NULL, 0, fmt, args); | |
1559 | } | |
1da177e4 LT |
1560 | EXPORT_SYMBOL(vprintk); |
1561 | ||
7ff9554b KS |
1562 | asmlinkage int printk_emit(int facility, int level, |
1563 | const char *dict, size_t dictlen, | |
1564 | const char *fmt, ...) | |
1565 | { | |
1566 | va_list args; | |
1567 | int r; | |
1568 | ||
1569 | va_start(args, fmt); | |
1570 | r = vprintk_emit(facility, level, dict, dictlen, fmt, args); | |
1571 | va_end(args); | |
1572 | ||
1573 | return r; | |
1574 | } | |
1575 | EXPORT_SYMBOL(printk_emit); | |
1576 | ||
1577 | /** | |
1578 | * printk - print a kernel message | |
1579 | * @fmt: format string | |
1580 | * | |
1581 | * This is printk(). It can be called from any context. We want it to work. | |
1582 | * | |
1583 | * We try to grab the console_lock. If we succeed, it's easy - we log the | |
1584 | * output and call the console drivers. If we fail to get the semaphore, we | |
1585 | * place the output into the log buffer and return. The current holder of | |
1586 | * the console_sem will notice the new output in console_unlock(); and will | |
1587 | * send it to the consoles before releasing the lock. | |
1588 | * | |
1589 | * One effect of this deferred printing is that code which calls printk() and | |
1590 | * then changes console_loglevel may break. This is because console_loglevel | |
1591 | * is inspected when the actual printing occurs. | |
1592 | * | |
1593 | * See also: | |
1594 | * printf(3) | |
1595 | * | |
1596 | * See the vsnprintf() documentation for format string extensions over C99. | |
1597 | */ | |
1598 | asmlinkage int printk(const char *fmt, ...) | |
1599 | { | |
1600 | va_list args; | |
1601 | int r; | |
1602 | ||
1603 | #ifdef CONFIG_KGDB_KDB | |
1604 | if (unlikely(kdb_trap_printk)) { | |
1605 | va_start(args, fmt); | |
1606 | r = vkdb_printf(fmt, args); | |
1607 | va_end(args); | |
1608 | return r; | |
1609 | } | |
1610 | #endif | |
1611 | va_start(args, fmt); | |
1612 | r = vprintk_emit(0, -1, NULL, 0, fmt, args); | |
1613 | va_end(args); | |
1614 | ||
1615 | return r; | |
1616 | } | |
1617 | EXPORT_SYMBOL(printk); | |
7f3a781d | 1618 | |
d59745ce MM |
1619 | #else |
1620 | ||
7f3a781d | 1621 | #define LOG_LINE_MAX 0 |
084681d1 KS |
1622 | static struct cont { |
1623 | size_t len; | |
1624 | size_t cons; | |
1625 | u8 level; | |
1626 | bool flushed:1; | |
1627 | } cont; | |
7f3a781d KS |
1628 | static struct log *log_from_idx(u32 idx) { return NULL; } |
1629 | static u32 log_next(u32 idx) { return 0; } | |
7f3a781d | 1630 | static void call_console_drivers(int level, const char *text, size_t len) {} |
5becfb1d KS |
1631 | static size_t msg_print_text(const struct log *msg, enum log_flags prev, |
1632 | bool syslog, char *buf, size_t size) { return 0; } | |
084681d1 | 1633 | static size_t cont_print_text(char *text, size_t size) { return 0; } |
d59745ce | 1634 | |
7f3a781d | 1635 | #endif /* CONFIG_PRINTK */ |
d59745ce | 1636 | |
f7511d5f ST |
1637 | static int __add_preferred_console(char *name, int idx, char *options, |
1638 | char *brl_options) | |
1639 | { | |
1640 | struct console_cmdline *c; | |
1641 | int i; | |
1642 | ||
1643 | /* | |
1644 | * See if this tty is not yet registered, and | |
1645 | * if we have a slot free. | |
1646 | */ | |
1647 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) | |
1648 | if (strcmp(console_cmdline[i].name, name) == 0 && | |
1649 | console_cmdline[i].index == idx) { | |
1650 | if (!brl_options) | |
1651 | selected_console = i; | |
1652 | return 0; | |
1653 | } | |
1654 | if (i == MAX_CMDLINECONSOLES) | |
1655 | return -E2BIG; | |
1656 | if (!brl_options) | |
1657 | selected_console = i; | |
1658 | c = &console_cmdline[i]; | |
1659 | strlcpy(c->name, name, sizeof(c->name)); | |
1660 | c->options = options; | |
1661 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE | |
1662 | c->brl_options = brl_options; | |
1663 | #endif | |
1664 | c->index = idx; | |
1665 | return 0; | |
1666 | } | |
2ea1c539 JB |
1667 | /* |
1668 | * Set up a list of consoles. Called from init/main.c | |
1669 | */ | |
1670 | static int __init console_setup(char *str) | |
1671 | { | |
eaa944af | 1672 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ |
f7511d5f | 1673 | char *s, *options, *brl_options = NULL; |
2ea1c539 JB |
1674 | int idx; |
1675 | ||
f7511d5f ST |
1676 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
1677 | if (!memcmp(str, "brl,", 4)) { | |
1678 | brl_options = ""; | |
1679 | str += 4; | |
1680 | } else if (!memcmp(str, "brl=", 4)) { | |
1681 | brl_options = str + 4; | |
1682 | str = strchr(brl_options, ','); | |
1683 | if (!str) { | |
1684 | printk(KERN_ERR "need port name after brl=\n"); | |
1685 | return 1; | |
1686 | } | |
1687 | *(str++) = 0; | |
1688 | } | |
1689 | #endif | |
1690 | ||
2ea1c539 JB |
1691 | /* |
1692 | * Decode str into name, index, options. | |
1693 | */ | |
1694 | if (str[0] >= '0' && str[0] <= '9') { | |
eaa944af YL |
1695 | strcpy(buf, "ttyS"); |
1696 | strncpy(buf + 4, str, sizeof(buf) - 5); | |
2ea1c539 | 1697 | } else { |
eaa944af | 1698 | strncpy(buf, str, sizeof(buf) - 1); |
2ea1c539 | 1699 | } |
eaa944af | 1700 | buf[sizeof(buf) - 1] = 0; |
2ea1c539 JB |
1701 | if ((options = strchr(str, ',')) != NULL) |
1702 | *(options++) = 0; | |
1703 | #ifdef __sparc__ | |
1704 | if (!strcmp(str, "ttya")) | |
eaa944af | 1705 | strcpy(buf, "ttyS0"); |
2ea1c539 | 1706 | if (!strcmp(str, "ttyb")) |
eaa944af | 1707 | strcpy(buf, "ttyS1"); |
2ea1c539 | 1708 | #endif |
eaa944af | 1709 | for (s = buf; *s; s++) |
2ea1c539 JB |
1710 | if ((*s >= '0' && *s <= '9') || *s == ',') |
1711 | break; | |
1712 | idx = simple_strtoul(s, NULL, 10); | |
1713 | *s = 0; | |
1714 | ||
f7511d5f | 1715 | __add_preferred_console(buf, idx, options, brl_options); |
9e124fe1 | 1716 | console_set_on_cmdline = 1; |
2ea1c539 JB |
1717 | return 1; |
1718 | } | |
1719 | __setup("console=", console_setup); | |
1720 | ||
3c0547ba MM |
1721 | /** |
1722 | * add_preferred_console - add a device to the list of preferred consoles. | |
ddad86c2 MW |
1723 | * @name: device name |
1724 | * @idx: device index | |
1725 | * @options: options for this console | |
3c0547ba MM |
1726 | * |
1727 | * The last preferred console added will be used for kernel messages | |
1728 | * and stdin/out/err for init. Normally this is used by console_setup | |
1729 | * above to handle user-supplied console arguments; however it can also | |
1730 | * be used by arch-specific code either to override the user or more | |
1731 | * commonly to provide a default console (ie from PROM variables) when | |
1732 | * the user has not supplied one. | |
1733 | */ | |
fb445ee5 | 1734 | int add_preferred_console(char *name, int idx, char *options) |
3c0547ba | 1735 | { |
f7511d5f | 1736 | return __add_preferred_console(name, idx, options, NULL); |
3c0547ba MM |
1737 | } |
1738 | ||
b6b1d877 | 1739 | int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options) |
18a8bd94 YL |
1740 | { |
1741 | struct console_cmdline *c; | |
1742 | int i; | |
1743 | ||
1744 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) | |
1745 | if (strcmp(console_cmdline[i].name, name) == 0 && | |
1746 | console_cmdline[i].index == idx) { | |
1747 | c = &console_cmdline[i]; | |
f735295b | 1748 | strlcpy(c->name, name_new, sizeof(c->name)); |
18a8bd94 YL |
1749 | c->name[sizeof(c->name) - 1] = 0; |
1750 | c->options = options; | |
1751 | c->index = idx_new; | |
1752 | return i; | |
1753 | } | |
1754 | /* not found */ | |
1755 | return -1; | |
1756 | } | |
1757 | ||
2329abfa | 1758 | bool console_suspend_enabled = 1; |
8f4ce8c3 AS |
1759 | EXPORT_SYMBOL(console_suspend_enabled); |
1760 | ||
1761 | static int __init console_suspend_disable(char *str) | |
1762 | { | |
1763 | console_suspend_enabled = 0; | |
1764 | return 1; | |
1765 | } | |
1766 | __setup("no_console_suspend", console_suspend_disable); | |
134620f7 YZ |
1767 | module_param_named(console_suspend, console_suspend_enabled, |
1768 | bool, S_IRUGO | S_IWUSR); | |
1769 | MODULE_PARM_DESC(console_suspend, "suspend console during suspend" | |
1770 | " and hibernate operations"); | |
8f4ce8c3 | 1771 | |
557240b4 LT |
1772 | /** |
1773 | * suspend_console - suspend the console subsystem | |
1774 | * | |
1775 | * This disables printk() while we go into suspend states | |
1776 | */ | |
1777 | void suspend_console(void) | |
1778 | { | |
8f4ce8c3 AS |
1779 | if (!console_suspend_enabled) |
1780 | return; | |
0d63081d | 1781 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
ac751efa | 1782 | console_lock(); |
557240b4 | 1783 | console_suspended = 1; |
403f3075 | 1784 | up(&console_sem); |
557240b4 LT |
1785 | } |
1786 | ||
1787 | void resume_console(void) | |
1788 | { | |
8f4ce8c3 AS |
1789 | if (!console_suspend_enabled) |
1790 | return; | |
403f3075 | 1791 | down(&console_sem); |
557240b4 | 1792 | console_suspended = 0; |
ac751efa | 1793 | console_unlock(); |
557240b4 LT |
1794 | } |
1795 | ||
034260d6 KC |
1796 | /** |
1797 | * console_cpu_notify - print deferred console messages after CPU hotplug | |
1798 | * @self: notifier struct | |
1799 | * @action: CPU hotplug event | |
1800 | * @hcpu: unused | |
1801 | * | |
1802 | * If printk() is called from a CPU that is not online yet, the messages | |
1803 | * will be spooled but will not show up on the console. This function is | |
1804 | * called when a new CPU comes online (or fails to come up), and ensures | |
1805 | * that any such output gets printed. | |
1806 | */ | |
1807 | static int __cpuinit console_cpu_notify(struct notifier_block *self, | |
1808 | unsigned long action, void *hcpu) | |
1809 | { | |
1810 | switch (action) { | |
1811 | case CPU_ONLINE: | |
1812 | case CPU_DEAD: | |
1813 | case CPU_DYING: | |
1814 | case CPU_DOWN_FAILED: | |
1815 | case CPU_UP_CANCELED: | |
ac751efa TH |
1816 | console_lock(); |
1817 | console_unlock(); | |
034260d6 KC |
1818 | } |
1819 | return NOTIFY_OK; | |
1820 | } | |
1821 | ||
1da177e4 | 1822 | /** |
ac751efa | 1823 | * console_lock - lock the console system for exclusive use. |
1da177e4 | 1824 | * |
ac751efa | 1825 | * Acquires a lock which guarantees that the caller has |
1da177e4 LT |
1826 | * exclusive access to the console system and the console_drivers list. |
1827 | * | |
1828 | * Can sleep, returns nothing. | |
1829 | */ | |
ac751efa | 1830 | void console_lock(void) |
1da177e4 | 1831 | { |
8abd8e29 | 1832 | BUG_ON(in_interrupt()); |
1da177e4 | 1833 | down(&console_sem); |
403f3075 AH |
1834 | if (console_suspended) |
1835 | return; | |
1da177e4 LT |
1836 | console_locked = 1; |
1837 | console_may_schedule = 1; | |
1838 | } | |
ac751efa | 1839 | EXPORT_SYMBOL(console_lock); |
1da177e4 | 1840 | |
ac751efa TH |
1841 | /** |
1842 | * console_trylock - try to lock the console system for exclusive use. | |
1843 | * | |
1844 | * Tried to acquire a lock which guarantees that the caller has | |
1845 | * exclusive access to the console system and the console_drivers list. | |
1846 | * | |
1847 | * returns 1 on success, and 0 on failure to acquire the lock. | |
1848 | */ | |
1849 | int console_trylock(void) | |
1da177e4 LT |
1850 | { |
1851 | if (down_trylock(&console_sem)) | |
ac751efa | 1852 | return 0; |
403f3075 AH |
1853 | if (console_suspended) { |
1854 | up(&console_sem); | |
ac751efa | 1855 | return 0; |
403f3075 | 1856 | } |
1da177e4 LT |
1857 | console_locked = 1; |
1858 | console_may_schedule = 0; | |
ac751efa | 1859 | return 1; |
1da177e4 | 1860 | } |
ac751efa | 1861 | EXPORT_SYMBOL(console_trylock); |
1da177e4 LT |
1862 | |
1863 | int is_console_locked(void) | |
1864 | { | |
1865 | return console_locked; | |
1866 | } | |
1da177e4 | 1867 | |
3ccf3e83 | 1868 | /* |
7ff9554b | 1869 | * Delayed printk version, for scheduler-internal messages: |
3ccf3e83 PZ |
1870 | */ |
1871 | #define PRINTK_BUF_SIZE 512 | |
1872 | ||
1873 | #define PRINTK_PENDING_WAKEUP 0x01 | |
1874 | #define PRINTK_PENDING_SCHED 0x02 | |
1875 | ||
b845b517 | 1876 | static DEFINE_PER_CPU(int, printk_pending); |
3ccf3e83 | 1877 | static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf); |
b845b517 PZ |
1878 | |
1879 | void printk_tick(void) | |
e3e8a75d | 1880 | { |
40dc11ff | 1881 | if (__this_cpu_read(printk_pending)) { |
3ccf3e83 PZ |
1882 | int pending = __this_cpu_xchg(printk_pending, 0); |
1883 | if (pending & PRINTK_PENDING_SCHED) { | |
1884 | char *buf = __get_cpu_var(printk_sched_buf); | |
1885 | printk(KERN_WARNING "[sched_delayed] %s", buf); | |
1886 | } | |
1887 | if (pending & PRINTK_PENDING_WAKEUP) | |
1888 | wake_up_interruptible(&log_wait); | |
b845b517 PZ |
1889 | } |
1890 | } | |
1891 | ||
1892 | int printk_needs_cpu(int cpu) | |
1893 | { | |
40dc11ff | 1894 | if (cpu_is_offline(cpu)) |
61ab2544 | 1895 | printk_tick(); |
40dc11ff | 1896 | return __this_cpu_read(printk_pending); |
b845b517 PZ |
1897 | } |
1898 | ||
1899 | void wake_up_klogd(void) | |
1900 | { | |
1901 | if (waitqueue_active(&log_wait)) | |
3ccf3e83 | 1902 | this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); |
e3e8a75d KK |
1903 | } |
1904 | ||
7ff9554b KS |
1905 | /* the next printk record to write to the console */ |
1906 | static u64 console_seq; | |
1907 | static u32 console_idx; | |
5becfb1d | 1908 | static enum log_flags console_prev; |
7ff9554b | 1909 | |
1da177e4 | 1910 | /** |
ac751efa | 1911 | * console_unlock - unlock the console system |
1da177e4 | 1912 | * |
ac751efa | 1913 | * Releases the console_lock which the caller holds on the console system |
1da177e4 LT |
1914 | * and the console driver list. |
1915 | * | |
ac751efa TH |
1916 | * While the console_lock was held, console output may have been buffered |
1917 | * by printk(). If this is the case, console_unlock(); emits | |
1918 | * the output prior to releasing the lock. | |
1da177e4 | 1919 | * |
7f3a781d | 1920 | * If there is output waiting, we wake /dev/kmsg and syslog() users. |
1da177e4 | 1921 | * |
ac751efa | 1922 | * console_unlock(); may be called from any context. |
1da177e4 | 1923 | */ |
ac751efa | 1924 | void console_unlock(void) |
1da177e4 | 1925 | { |
084681d1 | 1926 | static char text[LOG_LINE_MAX]; |
7ff9554b | 1927 | static u64 seen_seq; |
1da177e4 | 1928 | unsigned long flags; |
7ff9554b KS |
1929 | bool wake_klogd = false; |
1930 | bool retry; | |
1da177e4 | 1931 | |
557240b4 | 1932 | if (console_suspended) { |
403f3075 | 1933 | up(&console_sem); |
557240b4 LT |
1934 | return; |
1935 | } | |
78944e54 AD |
1936 | |
1937 | console_may_schedule = 0; | |
1938 | ||
084681d1 KS |
1939 | /* flush buffered message fragment immediately to console */ |
1940 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
1941 | if (cont.len && (cont.cons < cont.len || cont.flushed)) { | |
1942 | size_t len; | |
1943 | ||
1944 | len = cont_print_text(text, sizeof(text)); | |
1945 | raw_spin_unlock(&logbuf_lock); | |
1946 | stop_critical_timings(); | |
1947 | call_console_drivers(cont.level, text, len); | |
1948 | start_critical_timings(); | |
1949 | local_irq_restore(flags); | |
1950 | } else | |
1951 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
1952 | ||
4f2a8d3c | 1953 | again: |
7ff9554b KS |
1954 | for (;;) { |
1955 | struct log *msg; | |
3ce9a7c0 | 1956 | size_t len; |
7ff9554b KS |
1957 | int level; |
1958 | ||
07354eb1 | 1959 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
1960 | if (seen_seq != log_next_seq) { |
1961 | wake_klogd = true; | |
1962 | seen_seq = log_next_seq; | |
1963 | } | |
1964 | ||
1965 | if (console_seq < log_first_seq) { | |
1966 | /* messages are gone, move to first one */ | |
1967 | console_seq = log_first_seq; | |
1968 | console_idx = log_first_idx; | |
5becfb1d | 1969 | console_prev = 0; |
7ff9554b | 1970 | } |
084681d1 | 1971 | skip: |
7ff9554b KS |
1972 | if (console_seq == log_next_seq) |
1973 | break; | |
1974 | ||
1975 | msg = log_from_idx(console_idx); | |
084681d1 KS |
1976 | if (msg->flags & LOG_NOCONS) { |
1977 | /* | |
1978 | * Skip record we have buffered and already printed | |
1979 | * directly to the console when we received it. | |
1980 | */ | |
1981 | console_idx = log_next(console_idx); | |
1982 | console_seq++; | |
68b6507d KS |
1983 | /* |
1984 | * We will get here again when we register a new | |
1985 | * CON_PRINTBUFFER console. Clear the flag so we | |
1986 | * will properly dump everything later. | |
1987 | */ | |
1988 | msg->flags &= ~LOG_NOCONS; | |
084681d1 KS |
1989 | goto skip; |
1990 | } | |
649e6ee3 | 1991 | |
084681d1 | 1992 | level = msg->level; |
5becfb1d KS |
1993 | len = msg_print_text(msg, console_prev, false, |
1994 | text, sizeof(text)); | |
7ff9554b KS |
1995 | console_idx = log_next(console_idx); |
1996 | console_seq++; | |
5becfb1d | 1997 | console_prev = msg->flags; |
07354eb1 | 1998 | raw_spin_unlock(&logbuf_lock); |
7ff9554b | 1999 | |
81d68a96 | 2000 | stop_critical_timings(); /* don't trace print latency */ |
7ff9554b | 2001 | call_console_drivers(level, text, len); |
81d68a96 | 2002 | start_critical_timings(); |
1da177e4 LT |
2003 | local_irq_restore(flags); |
2004 | } | |
2005 | console_locked = 0; | |
fe3d8ad3 FT |
2006 | |
2007 | /* Release the exclusive_console once it is used */ | |
2008 | if (unlikely(exclusive_console)) | |
2009 | exclusive_console = NULL; | |
2010 | ||
07354eb1 | 2011 | raw_spin_unlock(&logbuf_lock); |
4f2a8d3c | 2012 | |
0b5e1c52 | 2013 | up(&console_sem); |
4f2a8d3c PZ |
2014 | |
2015 | /* | |
2016 | * Someone could have filled up the buffer again, so re-check if there's | |
2017 | * something to flush. In case we cannot trylock the console_sem again, | |
2018 | * there's a new owner and the console_unlock() from them will do the | |
2019 | * flush, no worries. | |
2020 | */ | |
07354eb1 | 2021 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 2022 | retry = console_seq != log_next_seq; |
09dc3cf9 PZ |
2023 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
2024 | ||
4f2a8d3c PZ |
2025 | if (retry && console_trylock()) |
2026 | goto again; | |
2027 | ||
e3e8a75d KK |
2028 | if (wake_klogd) |
2029 | wake_up_klogd(); | |
1da177e4 | 2030 | } |
ac751efa | 2031 | EXPORT_SYMBOL(console_unlock); |
1da177e4 | 2032 | |
ddad86c2 MW |
2033 | /** |
2034 | * console_conditional_schedule - yield the CPU if required | |
1da177e4 LT |
2035 | * |
2036 | * If the console code is currently allowed to sleep, and | |
2037 | * if this CPU should yield the CPU to another task, do | |
2038 | * so here. | |
2039 | * | |
ac751efa | 2040 | * Must be called within console_lock();. |
1da177e4 LT |
2041 | */ |
2042 | void __sched console_conditional_schedule(void) | |
2043 | { | |
2044 | if (console_may_schedule) | |
2045 | cond_resched(); | |
2046 | } | |
2047 | EXPORT_SYMBOL(console_conditional_schedule); | |
2048 | ||
1da177e4 LT |
2049 | void console_unblank(void) |
2050 | { | |
2051 | struct console *c; | |
2052 | ||
2053 | /* | |
2054 | * console_unblank can no longer be called in interrupt context unless | |
2055 | * oops_in_progress is set to 1.. | |
2056 | */ | |
2057 | if (oops_in_progress) { | |
2058 | if (down_trylock(&console_sem) != 0) | |
2059 | return; | |
2060 | } else | |
ac751efa | 2061 | console_lock(); |
1da177e4 LT |
2062 | |
2063 | console_locked = 1; | |
2064 | console_may_schedule = 0; | |
4d091611 | 2065 | for_each_console(c) |
1da177e4 LT |
2066 | if ((c->flags & CON_ENABLED) && c->unblank) |
2067 | c->unblank(); | |
ac751efa | 2068 | console_unlock(); |
1da177e4 | 2069 | } |
1da177e4 LT |
2070 | |
2071 | /* | |
2072 | * Return the console tty driver structure and its associated index | |
2073 | */ | |
2074 | struct tty_driver *console_device(int *index) | |
2075 | { | |
2076 | struct console *c; | |
2077 | struct tty_driver *driver = NULL; | |
2078 | ||
ac751efa | 2079 | console_lock(); |
4d091611 | 2080 | for_each_console(c) { |
1da177e4 LT |
2081 | if (!c->device) |
2082 | continue; | |
2083 | driver = c->device(c, index); | |
2084 | if (driver) | |
2085 | break; | |
2086 | } | |
ac751efa | 2087 | console_unlock(); |
1da177e4 LT |
2088 | return driver; |
2089 | } | |
2090 | ||
2091 | /* | |
2092 | * Prevent further output on the passed console device so that (for example) | |
2093 | * serial drivers can disable console output before suspending a port, and can | |
2094 | * re-enable output afterwards. | |
2095 | */ | |
2096 | void console_stop(struct console *console) | |
2097 | { | |
ac751efa | 2098 | console_lock(); |
1da177e4 | 2099 | console->flags &= ~CON_ENABLED; |
ac751efa | 2100 | console_unlock(); |
1da177e4 LT |
2101 | } |
2102 | EXPORT_SYMBOL(console_stop); | |
2103 | ||
2104 | void console_start(struct console *console) | |
2105 | { | |
ac751efa | 2106 | console_lock(); |
1da177e4 | 2107 | console->flags |= CON_ENABLED; |
ac751efa | 2108 | console_unlock(); |
1da177e4 LT |
2109 | } |
2110 | EXPORT_SYMBOL(console_start); | |
2111 | ||
7bf69395 FDN |
2112 | static int __read_mostly keep_bootcon; |
2113 | ||
2114 | static int __init keep_bootcon_setup(char *str) | |
2115 | { | |
2116 | keep_bootcon = 1; | |
2117 | printk(KERN_INFO "debug: skip boot console de-registration.\n"); | |
2118 | ||
2119 | return 0; | |
2120 | } | |
2121 | ||
2122 | early_param("keep_bootcon", keep_bootcon_setup); | |
2123 | ||
1da177e4 LT |
2124 | /* |
2125 | * The console driver calls this routine during kernel initialization | |
2126 | * to register the console printing procedure with printk() and to | |
2127 | * print any messages that were printed by the kernel before the | |
2128 | * console driver was initialized. | |
4d091611 RG |
2129 | * |
2130 | * This can happen pretty early during the boot process (because of | |
2131 | * early_printk) - sometimes before setup_arch() completes - be careful | |
2132 | * of what kernel features are used - they may not be initialised yet. | |
2133 | * | |
2134 | * There are two types of consoles - bootconsoles (early_printk) and | |
2135 | * "real" consoles (everything which is not a bootconsole) which are | |
2136 | * handled differently. | |
2137 | * - Any number of bootconsoles can be registered at any time. | |
2138 | * - As soon as a "real" console is registered, all bootconsoles | |
2139 | * will be unregistered automatically. | |
2140 | * - Once a "real" console is registered, any attempt to register a | |
2141 | * bootconsoles will be rejected | |
1da177e4 | 2142 | */ |
4d091611 | 2143 | void register_console(struct console *newcon) |
1da177e4 | 2144 | { |
40dc5651 | 2145 | int i; |
1da177e4 | 2146 | unsigned long flags; |
4d091611 | 2147 | struct console *bcon = NULL; |
1da177e4 | 2148 | |
4d091611 RG |
2149 | /* |
2150 | * before we register a new CON_BOOT console, make sure we don't | |
2151 | * already have a valid console | |
2152 | */ | |
2153 | if (console_drivers && newcon->flags & CON_BOOT) { | |
2154 | /* find the last or real console */ | |
2155 | for_each_console(bcon) { | |
2156 | if (!(bcon->flags & CON_BOOT)) { | |
2157 | printk(KERN_INFO "Too late to register bootconsole %s%d\n", | |
2158 | newcon->name, newcon->index); | |
2159 | return; | |
2160 | } | |
2161 | } | |
69331af7 GH |
2162 | } |
2163 | ||
4d091611 RG |
2164 | if (console_drivers && console_drivers->flags & CON_BOOT) |
2165 | bcon = console_drivers; | |
2166 | ||
2167 | if (preferred_console < 0 || bcon || !console_drivers) | |
1da177e4 LT |
2168 | preferred_console = selected_console; |
2169 | ||
4d091611 RG |
2170 | if (newcon->early_setup) |
2171 | newcon->early_setup(); | |
18a8bd94 | 2172 | |
1da177e4 LT |
2173 | /* |
2174 | * See if we want to use this console driver. If we | |
2175 | * didn't select a console we take the first one | |
2176 | * that registers here. | |
2177 | */ | |
2178 | if (preferred_console < 0) { | |
4d091611 RG |
2179 | if (newcon->index < 0) |
2180 | newcon->index = 0; | |
2181 | if (newcon->setup == NULL || | |
2182 | newcon->setup(newcon, NULL) == 0) { | |
2183 | newcon->flags |= CON_ENABLED; | |
2184 | if (newcon->device) { | |
2185 | newcon->flags |= CON_CONSDEV; | |
cd3a1b85 JK |
2186 | preferred_console = 0; |
2187 | } | |
1da177e4 LT |
2188 | } |
2189 | } | |
2190 | ||
2191 | /* | |
2192 | * See if this console matches one we selected on | |
2193 | * the command line. | |
2194 | */ | |
40dc5651 JJ |
2195 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; |
2196 | i++) { | |
4d091611 | 2197 | if (strcmp(console_cmdline[i].name, newcon->name) != 0) |
1da177e4 | 2198 | continue; |
4d091611 RG |
2199 | if (newcon->index >= 0 && |
2200 | newcon->index != console_cmdline[i].index) | |
1da177e4 | 2201 | continue; |
4d091611 RG |
2202 | if (newcon->index < 0) |
2203 | newcon->index = console_cmdline[i].index; | |
f7511d5f ST |
2204 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
2205 | if (console_cmdline[i].brl_options) { | |
4d091611 RG |
2206 | newcon->flags |= CON_BRL; |
2207 | braille_register_console(newcon, | |
f7511d5f ST |
2208 | console_cmdline[i].index, |
2209 | console_cmdline[i].options, | |
2210 | console_cmdline[i].brl_options); | |
2211 | return; | |
2212 | } | |
2213 | #endif | |
4d091611 RG |
2214 | if (newcon->setup && |
2215 | newcon->setup(newcon, console_cmdline[i].options) != 0) | |
1da177e4 | 2216 | break; |
4d091611 RG |
2217 | newcon->flags |= CON_ENABLED; |
2218 | newcon->index = console_cmdline[i].index; | |
ab4af03a | 2219 | if (i == selected_console) { |
4d091611 | 2220 | newcon->flags |= CON_CONSDEV; |
ab4af03a GE |
2221 | preferred_console = selected_console; |
2222 | } | |
1da177e4 LT |
2223 | break; |
2224 | } | |
2225 | ||
4d091611 | 2226 | if (!(newcon->flags & CON_ENABLED)) |
1da177e4 LT |
2227 | return; |
2228 | ||
8259cf43 RG |
2229 | /* |
2230 | * If we have a bootconsole, and are switching to a real console, | |
2231 | * don't print everything out again, since when the boot console, and | |
2232 | * the real console are the same physical device, it's annoying to | |
2233 | * see the beginning boot messages twice | |
2234 | */ | |
2235 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) | |
4d091611 | 2236 | newcon->flags &= ~CON_PRINTBUFFER; |
1da177e4 LT |
2237 | |
2238 | /* | |
2239 | * Put this console in the list - keep the | |
2240 | * preferred driver at the head of the list. | |
2241 | */ | |
ac751efa | 2242 | console_lock(); |
4d091611 RG |
2243 | if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
2244 | newcon->next = console_drivers; | |
2245 | console_drivers = newcon; | |
2246 | if (newcon->next) | |
2247 | newcon->next->flags &= ~CON_CONSDEV; | |
1da177e4 | 2248 | } else { |
4d091611 RG |
2249 | newcon->next = console_drivers->next; |
2250 | console_drivers->next = newcon; | |
1da177e4 | 2251 | } |
4d091611 | 2252 | if (newcon->flags & CON_PRINTBUFFER) { |
1da177e4 | 2253 | /* |
ac751efa | 2254 | * console_unlock(); will print out the buffered messages |
1da177e4 LT |
2255 | * for us. |
2256 | */ | |
07354eb1 | 2257 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2258 | console_seq = syslog_seq; |
2259 | console_idx = syslog_idx; | |
5becfb1d | 2260 | console_prev = syslog_prev; |
07354eb1 | 2261 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
fe3d8ad3 FT |
2262 | /* |
2263 | * We're about to replay the log buffer. Only do this to the | |
2264 | * just-registered console to avoid excessive message spam to | |
2265 | * the already-registered consoles. | |
2266 | */ | |
2267 | exclusive_console = newcon; | |
1da177e4 | 2268 | } |
ac751efa | 2269 | console_unlock(); |
fbc92a34 | 2270 | console_sysfs_notify(); |
8259cf43 RG |
2271 | |
2272 | /* | |
2273 | * By unregistering the bootconsoles after we enable the real console | |
2274 | * we get the "console xxx enabled" message on all the consoles - | |
2275 | * boot consoles, real consoles, etc - this is to ensure that end | |
2276 | * users know there might be something in the kernel's log buffer that | |
2277 | * went to the bootconsole (that they do not see on the real console) | |
2278 | */ | |
7bf69395 FDN |
2279 | if (bcon && |
2280 | ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && | |
2281 | !keep_bootcon) { | |
8259cf43 RG |
2282 | /* we need to iterate through twice, to make sure we print |
2283 | * everything out, before we unregister the console(s) | |
2284 | */ | |
2285 | printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n", | |
2286 | newcon->name, newcon->index); | |
2287 | for_each_console(bcon) | |
2288 | if (bcon->flags & CON_BOOT) | |
2289 | unregister_console(bcon); | |
2290 | } else { | |
2291 | printk(KERN_INFO "%sconsole [%s%d] enabled\n", | |
2292 | (newcon->flags & CON_BOOT) ? "boot" : "" , | |
2293 | newcon->name, newcon->index); | |
2294 | } | |
1da177e4 LT |
2295 | } |
2296 | EXPORT_SYMBOL(register_console); | |
2297 | ||
40dc5651 | 2298 | int unregister_console(struct console *console) |
1da177e4 | 2299 | { |
40dc5651 | 2300 | struct console *a, *b; |
1da177e4 LT |
2301 | int res = 1; |
2302 | ||
f7511d5f ST |
2303 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
2304 | if (console->flags & CON_BRL) | |
2305 | return braille_unregister_console(console); | |
2306 | #endif | |
2307 | ||
ac751efa | 2308 | console_lock(); |
1da177e4 LT |
2309 | if (console_drivers == console) { |
2310 | console_drivers=console->next; | |
2311 | res = 0; | |
e9b15b54 | 2312 | } else if (console_drivers) { |
1da177e4 LT |
2313 | for (a=console_drivers->next, b=console_drivers ; |
2314 | a; b=a, a=b->next) { | |
2315 | if (a == console) { | |
2316 | b->next = a->next; | |
2317 | res = 0; | |
2318 | break; | |
40dc5651 | 2319 | } |
1da177e4 LT |
2320 | } |
2321 | } | |
40dc5651 | 2322 | |
69331af7 | 2323 | /* |
ab4af03a GE |
2324 | * If this isn't the last console and it has CON_CONSDEV set, we |
2325 | * need to set it on the next preferred console. | |
1da177e4 | 2326 | */ |
69331af7 | 2327 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
ab4af03a | 2328 | console_drivers->flags |= CON_CONSDEV; |
1da177e4 | 2329 | |
ac751efa | 2330 | console_unlock(); |
fbc92a34 | 2331 | console_sysfs_notify(); |
1da177e4 LT |
2332 | return res; |
2333 | } | |
2334 | EXPORT_SYMBOL(unregister_console); | |
d59745ce | 2335 | |
034260d6 | 2336 | static int __init printk_late_init(void) |
0c5564bd | 2337 | { |
4d091611 RG |
2338 | struct console *con; |
2339 | ||
2340 | for_each_console(con) { | |
4c30c6f5 | 2341 | if (!keep_bootcon && con->flags & CON_BOOT) { |
cb00e99c | 2342 | printk(KERN_INFO "turn off boot console %s%d\n", |
4d091611 | 2343 | con->name, con->index); |
42c2c8c8 | 2344 | unregister_console(con); |
cb00e99c | 2345 | } |
0c5564bd | 2346 | } |
034260d6 | 2347 | hotcpu_notifier(console_cpu_notify, 0); |
0c5564bd RG |
2348 | return 0; |
2349 | } | |
034260d6 | 2350 | late_initcall(printk_late_init); |
0c5564bd | 2351 | |
7ef3d2fd | 2352 | #if defined CONFIG_PRINTK |
717115e1 | 2353 | |
600e1458 PZ |
2354 | int printk_sched(const char *fmt, ...) |
2355 | { | |
2356 | unsigned long flags; | |
2357 | va_list args; | |
2358 | char *buf; | |
2359 | int r; | |
2360 | ||
2361 | local_irq_save(flags); | |
2362 | buf = __get_cpu_var(printk_sched_buf); | |
2363 | ||
2364 | va_start(args, fmt); | |
2365 | r = vsnprintf(buf, PRINTK_BUF_SIZE, fmt, args); | |
2366 | va_end(args); | |
2367 | ||
2368 | __this_cpu_or(printk_pending, PRINTK_PENDING_SCHED); | |
2369 | local_irq_restore(flags); | |
2370 | ||
2371 | return r; | |
2372 | } | |
2373 | ||
1da177e4 LT |
2374 | /* |
2375 | * printk rate limiting, lifted from the networking subsystem. | |
2376 | * | |
641de9d8 UKK |
2377 | * This enforces a rate limit: not more than 10 kernel messages |
2378 | * every 5s to make a denial-of-service attack impossible. | |
1da177e4 | 2379 | */ |
641de9d8 UKK |
2380 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
2381 | ||
5c828713 | 2382 | int __printk_ratelimit(const char *func) |
1da177e4 | 2383 | { |
5c828713 | 2384 | return ___ratelimit(&printk_ratelimit_state, func); |
1da177e4 | 2385 | } |
5c828713 | 2386 | EXPORT_SYMBOL(__printk_ratelimit); |
f46c4833 AM |
2387 | |
2388 | /** | |
2389 | * printk_timed_ratelimit - caller-controlled printk ratelimiting | |
2390 | * @caller_jiffies: pointer to caller's state | |
2391 | * @interval_msecs: minimum interval between prints | |
2392 | * | |
2393 | * printk_timed_ratelimit() returns true if more than @interval_msecs | |
2394 | * milliseconds have elapsed since the last time printk_timed_ratelimit() | |
2395 | * returned true. | |
2396 | */ | |
2397 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, | |
2398 | unsigned int interval_msecs) | |
2399 | { | |
f2d28a2e GK |
2400 | if (*caller_jiffies == 0 |
2401 | || !time_in_range(jiffies, *caller_jiffies, | |
2402 | *caller_jiffies | |
2403 | + msecs_to_jiffies(interval_msecs))) { | |
2404 | *caller_jiffies = jiffies; | |
f46c4833 AM |
2405 | return true; |
2406 | } | |
2407 | return false; | |
2408 | } | |
2409 | EXPORT_SYMBOL(printk_timed_ratelimit); | |
456b565c SK |
2410 | |
2411 | static DEFINE_SPINLOCK(dump_list_lock); | |
2412 | static LIST_HEAD(dump_list); | |
2413 | ||
2414 | /** | |
2415 | * kmsg_dump_register - register a kernel log dumper. | |
6485536b | 2416 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2417 | * |
2418 | * Adds a kernel log dumper to the system. The dump callback in the | |
2419 | * structure will be called when the kernel oopses or panics and must be | |
2420 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. | |
2421 | */ | |
2422 | int kmsg_dump_register(struct kmsg_dumper *dumper) | |
2423 | { | |
2424 | unsigned long flags; | |
2425 | int err = -EBUSY; | |
2426 | ||
2427 | /* The dump callback needs to be set */ | |
2428 | if (!dumper->dump) | |
2429 | return -EINVAL; | |
2430 | ||
2431 | spin_lock_irqsave(&dump_list_lock, flags); | |
2432 | /* Don't allow registering multiple times */ | |
2433 | if (!dumper->registered) { | |
2434 | dumper->registered = 1; | |
fb842b00 | 2435 | list_add_tail_rcu(&dumper->list, &dump_list); |
456b565c SK |
2436 | err = 0; |
2437 | } | |
2438 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
2439 | ||
2440 | return err; | |
2441 | } | |
2442 | EXPORT_SYMBOL_GPL(kmsg_dump_register); | |
2443 | ||
2444 | /** | |
2445 | * kmsg_dump_unregister - unregister a kmsg dumper. | |
6485536b | 2446 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2447 | * |
2448 | * Removes a dump device from the system. Returns zero on success and | |
2449 | * %-EINVAL otherwise. | |
2450 | */ | |
2451 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) | |
2452 | { | |
2453 | unsigned long flags; | |
2454 | int err = -EINVAL; | |
2455 | ||
2456 | spin_lock_irqsave(&dump_list_lock, flags); | |
2457 | if (dumper->registered) { | |
2458 | dumper->registered = 0; | |
fb842b00 | 2459 | list_del_rcu(&dumper->list); |
456b565c SK |
2460 | err = 0; |
2461 | } | |
2462 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
fb842b00 | 2463 | synchronize_rcu(); |
456b565c SK |
2464 | |
2465 | return err; | |
2466 | } | |
2467 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); | |
2468 | ||
7ff9554b KS |
2469 | static bool always_kmsg_dump; |
2470 | module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); | |
2471 | ||
456b565c SK |
2472 | /** |
2473 | * kmsg_dump - dump kernel log to kernel message dumpers. | |
2474 | * @reason: the reason (oops, panic etc) for dumping | |
2475 | * | |
e2ae715d KS |
2476 | * Call each of the registered dumper's dump() callback, which can |
2477 | * retrieve the kmsg records with kmsg_dump_get_line() or | |
2478 | * kmsg_dump_get_buffer(). | |
456b565c SK |
2479 | */ |
2480 | void kmsg_dump(enum kmsg_dump_reason reason) | |
2481 | { | |
456b565c | 2482 | struct kmsg_dumper *dumper; |
456b565c SK |
2483 | unsigned long flags; |
2484 | ||
c22ab332 MG |
2485 | if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) |
2486 | return; | |
2487 | ||
e2ae715d KS |
2488 | rcu_read_lock(); |
2489 | list_for_each_entry_rcu(dumper, &dump_list, list) { | |
2490 | if (dumper->max_reason && reason > dumper->max_reason) | |
2491 | continue; | |
2492 | ||
2493 | /* initialize iterator with data about the stored records */ | |
2494 | dumper->active = true; | |
2495 | ||
2496 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2497 | dumper->cur_seq = clear_seq; | |
2498 | dumper->cur_idx = clear_idx; | |
2499 | dumper->next_seq = log_next_seq; | |
2500 | dumper->next_idx = log_next_idx; | |
2501 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2502 | ||
2503 | /* invoke dumper which will iterate over records */ | |
2504 | dumper->dump(dumper, reason); | |
2505 | ||
2506 | /* reset iterator */ | |
2507 | dumper->active = false; | |
2508 | } | |
2509 | rcu_read_unlock(); | |
2510 | } | |
2511 | ||
2512 | /** | |
533827c9 | 2513 | * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) |
e2ae715d KS |
2514 | * @dumper: registered kmsg dumper |
2515 | * @syslog: include the "<4>" prefixes | |
2516 | * @line: buffer to copy the line to | |
2517 | * @size: maximum size of the buffer | |
2518 | * @len: length of line placed into buffer | |
2519 | * | |
2520 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2521 | * record, and copy one record into the provided buffer. | |
2522 | * | |
2523 | * Consecutive calls will return the next available record moving | |
2524 | * towards the end of the buffer with the youngest messages. | |
2525 | * | |
2526 | * A return value of FALSE indicates that there are no more records to | |
2527 | * read. | |
533827c9 AV |
2528 | * |
2529 | * The function is similar to kmsg_dump_get_line(), but grabs no locks. | |
e2ae715d | 2530 | */ |
533827c9 AV |
2531 | bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, |
2532 | char *line, size_t size, size_t *len) | |
e2ae715d | 2533 | { |
e2ae715d KS |
2534 | struct log *msg; |
2535 | size_t l = 0; | |
2536 | bool ret = false; | |
2537 | ||
2538 | if (!dumper->active) | |
2539 | goto out; | |
7ff9554b | 2540 | |
e2ae715d KS |
2541 | if (dumper->cur_seq < log_first_seq) { |
2542 | /* messages are gone, move to first available one */ | |
2543 | dumper->cur_seq = log_first_seq; | |
2544 | dumper->cur_idx = log_first_idx; | |
2545 | } | |
456b565c | 2546 | |
e2ae715d | 2547 | /* last entry */ |
533827c9 | 2548 | if (dumper->cur_seq >= log_next_seq) |
e2ae715d | 2549 | goto out; |
456b565c | 2550 | |
e2ae715d | 2551 | msg = log_from_idx(dumper->cur_idx); |
5becfb1d | 2552 | l = msg_print_text(msg, 0, syslog, line, size); |
e2ae715d KS |
2553 | |
2554 | dumper->cur_idx = log_next(dumper->cur_idx); | |
2555 | dumper->cur_seq++; | |
2556 | ret = true; | |
e2ae715d KS |
2557 | out: |
2558 | if (len) | |
2559 | *len = l; | |
2560 | return ret; | |
2561 | } | |
533827c9 AV |
2562 | |
2563 | /** | |
2564 | * kmsg_dump_get_line - retrieve one kmsg log line | |
2565 | * @dumper: registered kmsg dumper | |
2566 | * @syslog: include the "<4>" prefixes | |
2567 | * @line: buffer to copy the line to | |
2568 | * @size: maximum size of the buffer | |
2569 | * @len: length of line placed into buffer | |
2570 | * | |
2571 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2572 | * record, and copy one record into the provided buffer. | |
2573 | * | |
2574 | * Consecutive calls will return the next available record moving | |
2575 | * towards the end of the buffer with the youngest messages. | |
2576 | * | |
2577 | * A return value of FALSE indicates that there are no more records to | |
2578 | * read. | |
2579 | */ | |
2580 | bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, | |
2581 | char *line, size_t size, size_t *len) | |
2582 | { | |
2583 | unsigned long flags; | |
2584 | bool ret; | |
2585 | ||
2586 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2587 | ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len); | |
2588 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2589 | ||
2590 | return ret; | |
2591 | } | |
e2ae715d KS |
2592 | EXPORT_SYMBOL_GPL(kmsg_dump_get_line); |
2593 | ||
2594 | /** | |
2595 | * kmsg_dump_get_buffer - copy kmsg log lines | |
2596 | * @dumper: registered kmsg dumper | |
2597 | * @syslog: include the "<4>" prefixes | |
4f0f4af5 | 2598 | * @buf: buffer to copy the line to |
e2ae715d KS |
2599 | * @size: maximum size of the buffer |
2600 | * @len: length of line placed into buffer | |
2601 | * | |
2602 | * Start at the end of the kmsg buffer and fill the provided buffer | |
2603 | * with as many of the the *youngest* kmsg records that fit into it. | |
2604 | * If the buffer is large enough, all available kmsg records will be | |
2605 | * copied with a single call. | |
2606 | * | |
2607 | * Consecutive calls will fill the buffer with the next block of | |
2608 | * available older records, not including the earlier retrieved ones. | |
2609 | * | |
2610 | * A return value of FALSE indicates that there are no more records to | |
2611 | * read. | |
2612 | */ | |
2613 | bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, | |
2614 | char *buf, size_t size, size_t *len) | |
2615 | { | |
2616 | unsigned long flags; | |
2617 | u64 seq; | |
2618 | u32 idx; | |
2619 | u64 next_seq; | |
2620 | u32 next_idx; | |
5becfb1d | 2621 | enum log_flags prev; |
e2ae715d KS |
2622 | size_t l = 0; |
2623 | bool ret = false; | |
2624 | ||
2625 | if (!dumper->active) | |
2626 | goto out; | |
2627 | ||
2628 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2629 | if (dumper->cur_seq < log_first_seq) { | |
2630 | /* messages are gone, move to first available one */ | |
2631 | dumper->cur_seq = log_first_seq; | |
2632 | dumper->cur_idx = log_first_idx; | |
2633 | } | |
2634 | ||
2635 | /* last entry */ | |
2636 | if (dumper->cur_seq >= dumper->next_seq) { | |
2637 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2638 | goto out; | |
2639 | } | |
2640 | ||
2641 | /* calculate length of entire buffer */ | |
2642 | seq = dumper->cur_seq; | |
2643 | idx = dumper->cur_idx; | |
5becfb1d | 2644 | prev = 0; |
e2ae715d KS |
2645 | while (seq < dumper->next_seq) { |
2646 | struct log *msg = log_from_idx(idx); | |
2647 | ||
5becfb1d | 2648 | l += msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
2649 | idx = log_next(idx); |
2650 | seq++; | |
5becfb1d | 2651 | prev = msg->flags; |
e2ae715d KS |
2652 | } |
2653 | ||
2654 | /* move first record forward until length fits into the buffer */ | |
2655 | seq = dumper->cur_seq; | |
2656 | idx = dumper->cur_idx; | |
5becfb1d | 2657 | prev = 0; |
e2ae715d KS |
2658 | while (l > size && seq < dumper->next_seq) { |
2659 | struct log *msg = log_from_idx(idx); | |
456b565c | 2660 | |
5becfb1d | 2661 | l -= msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
2662 | idx = log_next(idx); |
2663 | seq++; | |
5becfb1d | 2664 | prev = msg->flags; |
456b565c | 2665 | } |
e2ae715d KS |
2666 | |
2667 | /* last message in next interation */ | |
2668 | next_seq = seq; | |
2669 | next_idx = idx; | |
2670 | ||
2671 | l = 0; | |
5becfb1d | 2672 | prev = 0; |
e2ae715d KS |
2673 | while (seq < dumper->next_seq) { |
2674 | struct log *msg = log_from_idx(idx); | |
2675 | ||
5becfb1d | 2676 | l += msg_print_text(msg, prev, syslog, buf + l, size - l); |
e2ae715d KS |
2677 | idx = log_next(idx); |
2678 | seq++; | |
5becfb1d | 2679 | prev = msg->flags; |
e2ae715d KS |
2680 | } |
2681 | ||
2682 | dumper->next_seq = next_seq; | |
2683 | dumper->next_idx = next_idx; | |
2684 | ret = true; | |
7ff9554b | 2685 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
e2ae715d KS |
2686 | out: |
2687 | if (len) | |
2688 | *len = l; | |
2689 | return ret; | |
2690 | } | |
2691 | EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); | |
456b565c | 2692 | |
533827c9 AV |
2693 | /** |
2694 | * kmsg_dump_rewind_nolock - reset the interator (unlocked version) | |
2695 | * @dumper: registered kmsg dumper | |
2696 | * | |
2697 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
2698 | * kmsg_dump_get_buffer() can be called again and used multiple | |
2699 | * times within the same dumper.dump() callback. | |
2700 | * | |
2701 | * The function is similar to kmsg_dump_rewind(), but grabs no locks. | |
2702 | */ | |
2703 | void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) | |
2704 | { | |
2705 | dumper->cur_seq = clear_seq; | |
2706 | dumper->cur_idx = clear_idx; | |
2707 | dumper->next_seq = log_next_seq; | |
2708 | dumper->next_idx = log_next_idx; | |
2709 | } | |
2710 | ||
e2ae715d KS |
2711 | /** |
2712 | * kmsg_dump_rewind - reset the interator | |
2713 | * @dumper: registered kmsg dumper | |
2714 | * | |
2715 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
2716 | * kmsg_dump_get_buffer() can be called again and used multiple | |
2717 | * times within the same dumper.dump() callback. | |
2718 | */ | |
2719 | void kmsg_dump_rewind(struct kmsg_dumper *dumper) | |
2720 | { | |
2721 | unsigned long flags; | |
2722 | ||
2723 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
533827c9 | 2724 | kmsg_dump_rewind_nolock(dumper); |
e2ae715d | 2725 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
456b565c | 2726 | } |
e2ae715d | 2727 | EXPORT_SYMBOL_GPL(kmsg_dump_rewind); |
7ef3d2fd | 2728 | #endif |