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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/printk.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * Modified to make sys_syslog() more flexible: added commands to | |
7 | * return the last 4k of kernel messages, regardless of whether | |
8 | * they've been read or not. Added option to suppress kernel printk's | |
9 | * to the console. Added hook for sending the console messages | |
10 | * elsewhere, in preparation for a serial line console (someday). | |
11 | * Ted Ts'o, 2/11/93. | |
12 | * Modified for sysctl support, 1/8/97, Chris Horn. | |
40dc5651 | 13 | * Fixed SMP synchronization, 08/08/99, Manfred Spraul |
624dffcb | 14 | * manfred@colorfullife.com |
1da177e4 | 15 | * Rewrote bits to get rid of console_lock |
e1f8e874 | 16 | * 01Mar01 Andrew Morton |
1da177e4 LT |
17 | */ |
18 | ||
19 | #include <linux/kernel.h> | |
20 | #include <linux/mm.h> | |
21 | #include <linux/tty.h> | |
22 | #include <linux/tty_driver.h> | |
1da177e4 LT |
23 | #include <linux/console.h> |
24 | #include <linux/init.h> | |
bfe8df3d RD |
25 | #include <linux/jiffies.h> |
26 | #include <linux/nmi.h> | |
1da177e4 | 27 | #include <linux/module.h> |
3b9c0410 | 28 | #include <linux/moduleparam.h> |
1da177e4 | 29 | #include <linux/interrupt.h> /* For in_interrupt() */ |
1da177e4 LT |
30 | #include <linux/delay.h> |
31 | #include <linux/smp.h> | |
32 | #include <linux/security.h> | |
33 | #include <linux/bootmem.h> | |
162a7e75 | 34 | #include <linux/memblock.h> |
1da177e4 | 35 | #include <linux/syscalls.h> |
04d491ab | 36 | #include <linux/kexec.h> |
d37d39ae | 37 | #include <linux/kdb.h> |
3fff4c42 | 38 | #include <linux/ratelimit.h> |
456b565c | 39 | #include <linux/kmsg_dump.h> |
00234592 | 40 | #include <linux/syslog.h> |
034260d6 KC |
41 | #include <linux/cpu.h> |
42 | #include <linux/notifier.h> | |
fb842b00 | 43 | #include <linux/rculist.h> |
e11fea92 | 44 | #include <linux/poll.h> |
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 KS |
196 | enum log_flags { |
197 | LOG_DEFAULT = 0, | |
198 | LOG_NOCONS = 1, /* already flushed, do not print to console */ | |
199 | }; | |
200 | ||
7ff9554b KS |
201 | struct log { |
202 | u64 ts_nsec; /* timestamp in nanoseconds */ | |
203 | u16 len; /* length of entire record */ | |
204 | u16 text_len; /* length of text buffer */ | |
205 | u16 dict_len; /* length of dictionary buffer */ | |
084681d1 KS |
206 | u8 facility; /* syslog facility */ |
207 | u8 flags:5; /* internal record flags */ | |
208 | u8 level:3; /* syslog level */ | |
7ff9554b KS |
209 | }; |
210 | ||
211 | /* | |
212 | * The logbuf_lock protects kmsg buffer, indices, counters. It is also | |
213 | * used in interesting ways to provide interlocking in console_unlock(); | |
214 | */ | |
215 | static DEFINE_RAW_SPINLOCK(logbuf_lock); | |
d59745ce | 216 | |
7f3a781d KS |
217 | /* the next printk record to read by syslog(READ) or /proc/kmsg */ |
218 | static u64 syslog_seq; | |
219 | static u32 syslog_idx; | |
7ff9554b KS |
220 | |
221 | /* index and sequence number of the first record stored in the buffer */ | |
222 | static u64 log_first_seq; | |
223 | static u32 log_first_idx; | |
224 | ||
225 | /* index and sequence number of the next record to store in the buffer */ | |
226 | static u64 log_next_seq; | |
7f3a781d | 227 | #ifdef CONFIG_PRINTK |
7ff9554b KS |
228 | static u32 log_next_idx; |
229 | ||
230 | /* the next printk record to read after the last 'clear' command */ | |
231 | static u64 clear_seq; | |
232 | static u32 clear_idx; | |
233 | ||
7f3a781d KS |
234 | #define LOG_LINE_MAX 1024 |
235 | ||
236 | /* record buffer */ | |
6ebb017d | 237 | #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) |
f8450fca SW |
238 | #define LOG_ALIGN 4 |
239 | #else | |
6ebb017d | 240 | #define LOG_ALIGN __alignof__(struct log) |
f8450fca | 241 | #endif |
7f3a781d | 242 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
f8450fca | 243 | static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); |
7f3a781d KS |
244 | static char *log_buf = __log_buf; |
245 | static u32 log_buf_len = __LOG_BUF_LEN; | |
246 | ||
247 | /* cpu currently holding logbuf_lock */ | |
248 | static volatile unsigned int logbuf_cpu = UINT_MAX; | |
7ff9554b KS |
249 | |
250 | /* human readable text of the record */ | |
251 | static char *log_text(const struct log *msg) | |
252 | { | |
253 | return (char *)msg + sizeof(struct log); | |
254 | } | |
255 | ||
256 | /* optional key/value pair dictionary attached to the record */ | |
257 | static char *log_dict(const struct log *msg) | |
258 | { | |
259 | return (char *)msg + sizeof(struct log) + msg->text_len; | |
260 | } | |
261 | ||
262 | /* get record by index; idx must point to valid msg */ | |
263 | static struct log *log_from_idx(u32 idx) | |
264 | { | |
265 | struct log *msg = (struct log *)(log_buf + idx); | |
266 | ||
267 | /* | |
268 | * A length == 0 record is the end of buffer marker. Wrap around and | |
269 | * read the message at the start of the buffer. | |
270 | */ | |
271 | if (!msg->len) | |
272 | return (struct log *)log_buf; | |
273 | return msg; | |
274 | } | |
275 | ||
276 | /* get next record; idx must point to valid msg */ | |
277 | static u32 log_next(u32 idx) | |
278 | { | |
279 | struct log *msg = (struct log *)(log_buf + idx); | |
280 | ||
281 | /* length == 0 indicates the end of the buffer; wrap */ | |
282 | /* | |
283 | * A length == 0 record is the end of buffer marker. Wrap around and | |
284 | * read the message at the start of the buffer as *this* one, and | |
285 | * return the one after that. | |
286 | */ | |
287 | if (!msg->len) { | |
288 | msg = (struct log *)log_buf; | |
289 | return msg->len; | |
290 | } | |
291 | return idx + msg->len; | |
292 | } | |
293 | ||
7ff9554b KS |
294 | /* insert record into the buffer, discard old ones, update heads */ |
295 | static void log_store(int facility, int level, | |
084681d1 | 296 | enum log_flags flags, u64 ts_nsec, |
7ff9554b KS |
297 | const char *dict, u16 dict_len, |
298 | const char *text, u16 text_len) | |
299 | { | |
300 | struct log *msg; | |
301 | u32 size, pad_len; | |
302 | ||
303 | /* number of '\0' padding bytes to next message */ | |
304 | size = sizeof(struct log) + text_len + dict_len; | |
305 | pad_len = (-size) & (LOG_ALIGN - 1); | |
306 | size += pad_len; | |
307 | ||
308 | while (log_first_seq < log_next_seq) { | |
309 | u32 free; | |
310 | ||
311 | if (log_next_idx > log_first_idx) | |
312 | free = max(log_buf_len - log_next_idx, log_first_idx); | |
313 | else | |
314 | free = log_first_idx - log_next_idx; | |
315 | ||
316 | if (free > size + sizeof(struct log)) | |
317 | break; | |
318 | ||
319 | /* drop old messages until we have enough contiuous space */ | |
320 | log_first_idx = log_next(log_first_idx); | |
321 | log_first_seq++; | |
322 | } | |
323 | ||
324 | if (log_next_idx + size + sizeof(struct log) >= log_buf_len) { | |
325 | /* | |
326 | * This message + an additional empty header does not fit | |
327 | * at the end of the buffer. Add an empty header with len == 0 | |
328 | * to signify a wrap around. | |
329 | */ | |
330 | memset(log_buf + log_next_idx, 0, sizeof(struct log)); | |
331 | log_next_idx = 0; | |
332 | } | |
333 | ||
334 | /* fill message */ | |
335 | msg = (struct log *)(log_buf + log_next_idx); | |
336 | memcpy(log_text(msg), text, text_len); | |
337 | msg->text_len = text_len; | |
338 | memcpy(log_dict(msg), dict, dict_len); | |
339 | msg->dict_len = dict_len; | |
084681d1 KS |
340 | msg->facility = facility; |
341 | msg->level = level & 7; | |
342 | msg->flags = flags & 0x1f; | |
343 | if (ts_nsec > 0) | |
344 | msg->ts_nsec = ts_nsec; | |
345 | else | |
346 | msg->ts_nsec = local_clock(); | |
7ff9554b KS |
347 | memset(log_dict(msg) + dict_len, 0, pad_len); |
348 | msg->len = sizeof(struct log) + text_len + dict_len + pad_len; | |
349 | ||
350 | /* insert message */ | |
351 | log_next_idx += msg->len; | |
352 | log_next_seq++; | |
353 | } | |
d59745ce | 354 | |
e11fea92 KS |
355 | /* /dev/kmsg - userspace message inject/listen interface */ |
356 | struct devkmsg_user { | |
357 | u64 seq; | |
358 | u32 idx; | |
359 | struct mutex lock; | |
360 | char buf[8192]; | |
361 | }; | |
362 | ||
363 | static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv, | |
364 | unsigned long count, loff_t pos) | |
365 | { | |
366 | char *buf, *line; | |
367 | int i; | |
368 | int level = default_message_loglevel; | |
369 | int facility = 1; /* LOG_USER */ | |
370 | size_t len = iov_length(iv, count); | |
371 | ssize_t ret = len; | |
372 | ||
373 | if (len > LOG_LINE_MAX) | |
374 | return -EINVAL; | |
375 | buf = kmalloc(len+1, GFP_KERNEL); | |
376 | if (buf == NULL) | |
377 | return -ENOMEM; | |
378 | ||
379 | line = buf; | |
380 | for (i = 0; i < count; i++) { | |
381 | if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) | |
382 | goto out; | |
383 | line += iv[i].iov_len; | |
384 | } | |
385 | ||
386 | /* | |
387 | * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace | |
388 | * the decimal value represents 32bit, the lower 3 bit are the log | |
389 | * level, the rest are the log facility. | |
390 | * | |
391 | * If no prefix or no userspace facility is specified, we | |
392 | * enforce LOG_USER, to be able to reliably distinguish | |
393 | * kernel-generated messages from userspace-injected ones. | |
394 | */ | |
395 | line = buf; | |
396 | if (line[0] == '<') { | |
397 | char *endp = NULL; | |
398 | ||
399 | i = simple_strtoul(line+1, &endp, 10); | |
400 | if (endp && endp[0] == '>') { | |
401 | level = i & 7; | |
402 | if (i >> 3) | |
403 | facility = i >> 3; | |
404 | endp++; | |
405 | len -= endp - line; | |
406 | line = endp; | |
407 | } | |
408 | } | |
409 | line[len] = '\0'; | |
410 | ||
411 | printk_emit(facility, level, NULL, 0, "%s", line); | |
412 | out: | |
413 | kfree(buf); | |
414 | return ret; | |
415 | } | |
416 | ||
417 | static ssize_t devkmsg_read(struct file *file, char __user *buf, | |
418 | size_t count, loff_t *ppos) | |
419 | { | |
420 | struct devkmsg_user *user = file->private_data; | |
421 | struct log *msg; | |
5fc32490 | 422 | u64 ts_usec; |
e11fea92 KS |
423 | size_t i; |
424 | size_t len; | |
425 | ssize_t ret; | |
426 | ||
427 | if (!user) | |
428 | return -EBADF; | |
429 | ||
4a77a5a0 YL |
430 | ret = mutex_lock_interruptible(&user->lock); |
431 | if (ret) | |
432 | return ret; | |
5c53d819 | 433 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
434 | while (user->seq == log_next_seq) { |
435 | if (file->f_flags & O_NONBLOCK) { | |
436 | ret = -EAGAIN; | |
5c53d819 | 437 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
438 | goto out; |
439 | } | |
440 | ||
5c53d819 | 441 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
442 | ret = wait_event_interruptible(log_wait, |
443 | user->seq != log_next_seq); | |
444 | if (ret) | |
445 | goto out; | |
5c53d819 | 446 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
447 | } |
448 | ||
449 | if (user->seq < log_first_seq) { | |
450 | /* our last seen message is gone, return error and reset */ | |
451 | user->idx = log_first_idx; | |
452 | user->seq = log_first_seq; | |
453 | ret = -EPIPE; | |
5c53d819 | 454 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
455 | goto out; |
456 | } | |
457 | ||
458 | msg = log_from_idx(user->idx); | |
5fc32490 KS |
459 | ts_usec = msg->ts_nsec; |
460 | do_div(ts_usec, 1000); | |
e11fea92 | 461 | len = sprintf(user->buf, "%u,%llu,%llu;", |
084681d1 | 462 | (msg->facility << 3) | msg->level, user->seq, ts_usec); |
e11fea92 KS |
463 | |
464 | /* escape non-printable characters */ | |
465 | for (i = 0; i < msg->text_len; i++) { | |
3ce9a7c0 | 466 | unsigned char c = log_text(msg)[i]; |
e11fea92 | 467 | |
e3f5a5f2 | 468 | if (c < ' ' || c >= 127 || c == '\\') |
e11fea92 KS |
469 | len += sprintf(user->buf + len, "\\x%02x", c); |
470 | else | |
471 | user->buf[len++] = c; | |
472 | } | |
473 | user->buf[len++] = '\n'; | |
474 | ||
475 | if (msg->dict_len) { | |
476 | bool line = true; | |
477 | ||
478 | for (i = 0; i < msg->dict_len; i++) { | |
3ce9a7c0 | 479 | unsigned char c = log_dict(msg)[i]; |
e11fea92 KS |
480 | |
481 | if (line) { | |
482 | user->buf[len++] = ' '; | |
483 | line = false; | |
484 | } | |
485 | ||
486 | if (c == '\0') { | |
487 | user->buf[len++] = '\n'; | |
488 | line = true; | |
489 | continue; | |
490 | } | |
491 | ||
e3f5a5f2 | 492 | if (c < ' ' || c >= 127 || c == '\\') { |
e11fea92 KS |
493 | len += sprintf(user->buf + len, "\\x%02x", c); |
494 | continue; | |
495 | } | |
496 | ||
497 | user->buf[len++] = c; | |
498 | } | |
499 | user->buf[len++] = '\n'; | |
500 | } | |
501 | ||
502 | user->idx = log_next(user->idx); | |
503 | user->seq++; | |
5c53d819 | 504 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
505 | |
506 | if (len > count) { | |
507 | ret = -EINVAL; | |
508 | goto out; | |
509 | } | |
510 | ||
511 | if (copy_to_user(buf, user->buf, len)) { | |
512 | ret = -EFAULT; | |
513 | goto out; | |
514 | } | |
515 | ret = len; | |
516 | out: | |
517 | mutex_unlock(&user->lock); | |
518 | return ret; | |
519 | } | |
520 | ||
521 | static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) | |
522 | { | |
523 | struct devkmsg_user *user = file->private_data; | |
524 | loff_t ret = 0; | |
525 | ||
526 | if (!user) | |
527 | return -EBADF; | |
528 | if (offset) | |
529 | return -ESPIPE; | |
530 | ||
5c53d819 | 531 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
532 | switch (whence) { |
533 | case SEEK_SET: | |
534 | /* the first record */ | |
535 | user->idx = log_first_idx; | |
536 | user->seq = log_first_seq; | |
537 | break; | |
538 | case SEEK_DATA: | |
539 | /* | |
540 | * The first record after the last SYSLOG_ACTION_CLEAR, | |
541 | * like issued by 'dmesg -c'. Reading /dev/kmsg itself | |
542 | * changes no global state, and does not clear anything. | |
543 | */ | |
544 | user->idx = clear_idx; | |
545 | user->seq = clear_seq; | |
546 | break; | |
547 | case SEEK_END: | |
548 | /* after the last record */ | |
549 | user->idx = log_next_idx; | |
550 | user->seq = log_next_seq; | |
551 | break; | |
552 | default: | |
553 | ret = -EINVAL; | |
554 | } | |
5c53d819 | 555 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
556 | return ret; |
557 | } | |
558 | ||
559 | static unsigned int devkmsg_poll(struct file *file, poll_table *wait) | |
560 | { | |
561 | struct devkmsg_user *user = file->private_data; | |
562 | int ret = 0; | |
563 | ||
564 | if (!user) | |
565 | return POLLERR|POLLNVAL; | |
566 | ||
567 | poll_wait(file, &log_wait, wait); | |
568 | ||
5c53d819 | 569 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
570 | if (user->seq < log_next_seq) { |
571 | /* return error when data has vanished underneath us */ | |
572 | if (user->seq < log_first_seq) | |
573 | ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI; | |
574 | ret = POLLIN|POLLRDNORM; | |
575 | } | |
5c53d819 | 576 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
577 | |
578 | return ret; | |
579 | } | |
580 | ||
581 | static int devkmsg_open(struct inode *inode, struct file *file) | |
582 | { | |
583 | struct devkmsg_user *user; | |
584 | int err; | |
585 | ||
586 | /* write-only does not need any file context */ | |
587 | if ((file->f_flags & O_ACCMODE) == O_WRONLY) | |
588 | return 0; | |
589 | ||
590 | err = security_syslog(SYSLOG_ACTION_READ_ALL); | |
591 | if (err) | |
592 | return err; | |
593 | ||
594 | user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL); | |
595 | if (!user) | |
596 | return -ENOMEM; | |
597 | ||
598 | mutex_init(&user->lock); | |
599 | ||
5c53d819 | 600 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
601 | user->idx = log_first_idx; |
602 | user->seq = log_first_seq; | |
5c53d819 | 603 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
604 | |
605 | file->private_data = user; | |
606 | return 0; | |
607 | } | |
608 | ||
609 | static int devkmsg_release(struct inode *inode, struct file *file) | |
610 | { | |
611 | struct devkmsg_user *user = file->private_data; | |
612 | ||
613 | if (!user) | |
614 | return 0; | |
615 | ||
616 | mutex_destroy(&user->lock); | |
617 | kfree(user); | |
618 | return 0; | |
619 | } | |
620 | ||
621 | const struct file_operations kmsg_fops = { | |
622 | .open = devkmsg_open, | |
623 | .read = devkmsg_read, | |
624 | .aio_write = devkmsg_writev, | |
625 | .llseek = devkmsg_llseek, | |
626 | .poll = devkmsg_poll, | |
627 | .release = devkmsg_release, | |
628 | }; | |
629 | ||
04d491ab NH |
630 | #ifdef CONFIG_KEXEC |
631 | /* | |
632 | * This appends the listed symbols to /proc/vmcoreinfo | |
633 | * | |
634 | * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to | |
635 | * obtain access to symbols that are otherwise very difficult to locate. These | |
636 | * symbols are specifically used so that utilities can access and extract the | |
637 | * dmesg log from a vmcore file after a crash. | |
638 | */ | |
639 | void log_buf_kexec_setup(void) | |
640 | { | |
641 | VMCOREINFO_SYMBOL(log_buf); | |
04d491ab | 642 | VMCOREINFO_SYMBOL(log_buf_len); |
7ff9554b KS |
643 | VMCOREINFO_SYMBOL(log_first_idx); |
644 | VMCOREINFO_SYMBOL(log_next_idx); | |
04d491ab NH |
645 | } |
646 | #endif | |
647 | ||
162a7e75 MT |
648 | /* requested log_buf_len from kernel cmdline */ |
649 | static unsigned long __initdata new_log_buf_len; | |
650 | ||
651 | /* save requested log_buf_len since it's too early to process it */ | |
1da177e4 LT |
652 | static int __init log_buf_len_setup(char *str) |
653 | { | |
eed4a2ab | 654 | unsigned size = memparse(str, &str); |
1da177e4 LT |
655 | |
656 | if (size) | |
657 | size = roundup_pow_of_two(size); | |
162a7e75 MT |
658 | if (size > log_buf_len) |
659 | new_log_buf_len = size; | |
660 | ||
661 | return 0; | |
1da177e4 | 662 | } |
162a7e75 MT |
663 | early_param("log_buf_len", log_buf_len_setup); |
664 | ||
665 | void __init setup_log_buf(int early) | |
666 | { | |
667 | unsigned long flags; | |
162a7e75 MT |
668 | char *new_log_buf; |
669 | int free; | |
670 | ||
671 | if (!new_log_buf_len) | |
672 | return; | |
1da177e4 | 673 | |
162a7e75 MT |
674 | if (early) { |
675 | unsigned long mem; | |
676 | ||
677 | mem = memblock_alloc(new_log_buf_len, PAGE_SIZE); | |
1f5026a7 | 678 | if (!mem) |
162a7e75 MT |
679 | return; |
680 | new_log_buf = __va(mem); | |
681 | } else { | |
682 | new_log_buf = alloc_bootmem_nopanic(new_log_buf_len); | |
683 | } | |
684 | ||
685 | if (unlikely(!new_log_buf)) { | |
686 | pr_err("log_buf_len: %ld bytes not available\n", | |
687 | new_log_buf_len); | |
688 | return; | |
689 | } | |
690 | ||
07354eb1 | 691 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
162a7e75 MT |
692 | log_buf_len = new_log_buf_len; |
693 | log_buf = new_log_buf; | |
694 | new_log_buf_len = 0; | |
7ff9554b KS |
695 | free = __LOG_BUF_LEN - log_next_idx; |
696 | memcpy(log_buf, __log_buf, __LOG_BUF_LEN); | |
07354eb1 | 697 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
162a7e75 MT |
698 | |
699 | pr_info("log_buf_len: %d\n", log_buf_len); | |
700 | pr_info("early log buf free: %d(%d%%)\n", | |
701 | free, (free * 100) / __LOG_BUF_LEN); | |
702 | } | |
1da177e4 | 703 | |
bfe8df3d RD |
704 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
705 | ||
674dff65 | 706 | static int boot_delay; /* msecs delay after each printk during bootup */ |
3a3b6ed2 | 707 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
bfe8df3d RD |
708 | |
709 | static int __init boot_delay_setup(char *str) | |
710 | { | |
711 | unsigned long lpj; | |
bfe8df3d RD |
712 | |
713 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ | |
714 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; | |
715 | ||
716 | get_option(&str, &boot_delay); | |
717 | if (boot_delay > 10 * 1000) | |
718 | boot_delay = 0; | |
719 | ||
3a3b6ed2 DY |
720 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
721 | "HZ: %d, loops_per_msec: %llu\n", | |
722 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); | |
bfe8df3d RD |
723 | return 1; |
724 | } | |
725 | __setup("boot_delay=", boot_delay_setup); | |
726 | ||
727 | static void boot_delay_msec(void) | |
728 | { | |
729 | unsigned long long k; | |
730 | unsigned long timeout; | |
731 | ||
732 | if (boot_delay == 0 || system_state != SYSTEM_BOOTING) | |
733 | return; | |
734 | ||
3a3b6ed2 | 735 | k = (unsigned long long)loops_per_msec * boot_delay; |
bfe8df3d RD |
736 | |
737 | timeout = jiffies + msecs_to_jiffies(boot_delay); | |
738 | while (k) { | |
739 | k--; | |
740 | cpu_relax(); | |
741 | /* | |
742 | * use (volatile) jiffies to prevent | |
743 | * compiler reduction; loop termination via jiffies | |
744 | * is secondary and may or may not happen. | |
745 | */ | |
746 | if (time_after(jiffies, timeout)) | |
747 | break; | |
748 | touch_nmi_watchdog(); | |
749 | } | |
750 | } | |
751 | #else | |
752 | static inline void boot_delay_msec(void) | |
753 | { | |
754 | } | |
755 | #endif | |
756 | ||
eaf06b24 DR |
757 | #ifdef CONFIG_SECURITY_DMESG_RESTRICT |
758 | int dmesg_restrict = 1; | |
759 | #else | |
760 | int dmesg_restrict; | |
761 | #endif | |
762 | ||
ee24aebf LT |
763 | static int syslog_action_restricted(int type) |
764 | { | |
765 | if (dmesg_restrict) | |
766 | return 1; | |
767 | /* Unless restricted, we allow "read all" and "get buffer size" for everybody */ | |
768 | return type != SYSLOG_ACTION_READ_ALL && type != SYSLOG_ACTION_SIZE_BUFFER; | |
769 | } | |
770 | ||
771 | static int check_syslog_permissions(int type, bool from_file) | |
772 | { | |
773 | /* | |
774 | * If this is from /proc/kmsg and we've already opened it, then we've | |
775 | * already done the capabilities checks at open time. | |
776 | */ | |
777 | if (from_file && type != SYSLOG_ACTION_OPEN) | |
778 | return 0; | |
779 | ||
780 | if (syslog_action_restricted(type)) { | |
781 | if (capable(CAP_SYSLOG)) | |
782 | return 0; | |
783 | /* For historical reasons, accept CAP_SYS_ADMIN too, with a warning */ | |
784 | if (capable(CAP_SYS_ADMIN)) { | |
f2c0d026 JN |
785 | printk_once(KERN_WARNING "%s (%d): " |
786 | "Attempt to access syslog with CAP_SYS_ADMIN " | |
787 | "but no CAP_SYSLOG (deprecated).\n", | |
788 | current->comm, task_pid_nr(current)); | |
ee24aebf LT |
789 | return 0; |
790 | } | |
791 | return -EPERM; | |
792 | } | |
793 | return 0; | |
794 | } | |
795 | ||
7ff9554b KS |
796 | #if defined(CONFIG_PRINTK_TIME) |
797 | static bool printk_time = 1; | |
798 | #else | |
799 | static bool printk_time; | |
800 | #endif | |
801 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); | |
802 | ||
084681d1 KS |
803 | static size_t print_time(u64 ts, char *buf) |
804 | { | |
805 | unsigned long rem_nsec; | |
806 | ||
807 | if (!printk_time) | |
808 | return 0; | |
809 | ||
810 | if (!buf) | |
811 | return 15; | |
812 | ||
813 | rem_nsec = do_div(ts, 1000000000); | |
814 | return sprintf(buf, "[%5lu.%06lu] ", | |
815 | (unsigned long)ts, rem_nsec / 1000); | |
816 | } | |
817 | ||
3ce9a7c0 | 818 | static size_t print_prefix(const struct log *msg, bool syslog, char *buf) |
649e6ee3 | 819 | { |
3ce9a7c0 | 820 | size_t len = 0; |
43a73a50 | 821 | unsigned int prefix = (msg->facility << 3) | msg->level; |
649e6ee3 | 822 | |
3ce9a7c0 KS |
823 | if (syslog) { |
824 | if (buf) { | |
43a73a50 | 825 | len += sprintf(buf, "<%u>", prefix); |
3ce9a7c0 KS |
826 | } else { |
827 | len += 3; | |
43a73a50 KS |
828 | if (prefix > 999) |
829 | len += 3; | |
830 | else if (prefix > 99) | |
831 | len += 2; | |
832 | else if (prefix > 9) | |
3ce9a7c0 KS |
833 | len++; |
834 | } | |
835 | } | |
649e6ee3 | 836 | |
084681d1 | 837 | len += print_time(msg->ts_nsec, buf ? buf + len : NULL); |
3ce9a7c0 | 838 | return len; |
649e6ee3 KS |
839 | } |
840 | ||
3ce9a7c0 KS |
841 | static size_t msg_print_text(const struct log *msg, bool syslog, |
842 | char *buf, size_t size) | |
7ff9554b | 843 | { |
3ce9a7c0 KS |
844 | const char *text = log_text(msg); |
845 | size_t text_size = msg->text_len; | |
846 | size_t len = 0; | |
847 | ||
848 | do { | |
849 | const char *next = memchr(text, '\n', text_size); | |
850 | size_t text_len; | |
851 | ||
852 | if (next) { | |
853 | text_len = next - text; | |
854 | next++; | |
855 | text_size -= next - text; | |
856 | } else { | |
857 | text_len = text_size; | |
858 | } | |
7ff9554b | 859 | |
3ce9a7c0 KS |
860 | if (buf) { |
861 | if (print_prefix(msg, syslog, NULL) + | |
862 | text_len + 1>= size - len) | |
863 | break; | |
7ff9554b | 864 | |
3ce9a7c0 KS |
865 | len += print_prefix(msg, syslog, buf + len); |
866 | memcpy(buf + len, text, text_len); | |
867 | len += text_len; | |
868 | buf[len++] = '\n'; | |
869 | } else { | |
870 | /* SYSLOG_ACTION_* buffer size only calculation */ | |
871 | len += print_prefix(msg, syslog, NULL); | |
872 | len += text_len + 1; | |
873 | } | |
7ff9554b | 874 | |
3ce9a7c0 KS |
875 | text = next; |
876 | } while (text); | |
7ff9554b | 877 | |
7ff9554b KS |
878 | return len; |
879 | } | |
880 | ||
881 | static int syslog_print(char __user *buf, int size) | |
882 | { | |
883 | char *text; | |
3ce9a7c0 | 884 | struct log *msg; |
116e90b2 | 885 | int len = 0; |
7ff9554b KS |
886 | |
887 | text = kmalloc(LOG_LINE_MAX, GFP_KERNEL); | |
888 | if (!text) | |
889 | return -ENOMEM; | |
890 | ||
116e90b2 JB |
891 | while (size > 0) { |
892 | size_t n; | |
893 | ||
894 | raw_spin_lock_irq(&logbuf_lock); | |
895 | if (syslog_seq < log_first_seq) { | |
896 | /* messages are gone, move to first one */ | |
897 | syslog_seq = log_first_seq; | |
898 | syslog_idx = log_first_idx; | |
899 | } | |
900 | if (syslog_seq == log_next_seq) { | |
901 | raw_spin_unlock_irq(&logbuf_lock); | |
902 | break; | |
903 | } | |
904 | msg = log_from_idx(syslog_idx); | |
905 | n = msg_print_text(msg, true, text, LOG_LINE_MAX); | |
906 | if (n <= size) { | |
907 | syslog_idx = log_next(syslog_idx); | |
908 | syslog_seq++; | |
909 | } else | |
910 | n = 0; | |
911 | raw_spin_unlock_irq(&logbuf_lock); | |
912 | ||
913 | if (!n) | |
914 | break; | |
915 | ||
916 | len += n; | |
917 | size -= n; | |
918 | buf += n; | |
919 | n = copy_to_user(buf - n, text, n); | |
920 | ||
921 | if (n) { | |
922 | len -= n; | |
923 | if (!len) | |
924 | len = -EFAULT; | |
925 | break; | |
926 | } | |
7ff9554b | 927 | } |
7ff9554b KS |
928 | |
929 | kfree(text); | |
930 | return len; | |
931 | } | |
932 | ||
933 | static int syslog_print_all(char __user *buf, int size, bool clear) | |
934 | { | |
935 | char *text; | |
936 | int len = 0; | |
937 | ||
938 | text = kmalloc(LOG_LINE_MAX, GFP_KERNEL); | |
939 | if (!text) | |
940 | return -ENOMEM; | |
941 | ||
942 | raw_spin_lock_irq(&logbuf_lock); | |
943 | if (buf) { | |
944 | u64 next_seq; | |
945 | u64 seq; | |
946 | u32 idx; | |
947 | ||
948 | if (clear_seq < log_first_seq) { | |
949 | /* messages are gone, move to first available one */ | |
950 | clear_seq = log_first_seq; | |
951 | clear_idx = log_first_idx; | |
952 | } | |
953 | ||
954 | /* | |
955 | * Find first record that fits, including all following records, | |
956 | * into the user-provided buffer for this dump. | |
e2ae715d | 957 | */ |
7ff9554b KS |
958 | seq = clear_seq; |
959 | idx = clear_idx; | |
960 | while (seq < log_next_seq) { | |
3ce9a7c0 KS |
961 | struct log *msg = log_from_idx(idx); |
962 | ||
963 | len += msg_print_text(msg, true, NULL, 0); | |
7ff9554b KS |
964 | idx = log_next(idx); |
965 | seq++; | |
966 | } | |
e2ae715d KS |
967 | |
968 | /* move first record forward until length fits into the buffer */ | |
7ff9554b KS |
969 | seq = clear_seq; |
970 | idx = clear_idx; | |
971 | while (len > size && seq < log_next_seq) { | |
3ce9a7c0 KS |
972 | struct log *msg = log_from_idx(idx); |
973 | ||
974 | len -= msg_print_text(msg, true, NULL, 0); | |
7ff9554b KS |
975 | idx = log_next(idx); |
976 | seq++; | |
977 | } | |
978 | ||
e2ae715d | 979 | /* last message fitting into this dump */ |
7ff9554b KS |
980 | next_seq = log_next_seq; |
981 | ||
982 | len = 0; | |
983 | while (len >= 0 && seq < next_seq) { | |
3ce9a7c0 | 984 | struct log *msg = log_from_idx(idx); |
7ff9554b KS |
985 | int textlen; |
986 | ||
3ce9a7c0 | 987 | textlen = msg_print_text(msg, true, text, LOG_LINE_MAX); |
7ff9554b KS |
988 | if (textlen < 0) { |
989 | len = textlen; | |
990 | break; | |
991 | } | |
992 | idx = log_next(idx); | |
993 | seq++; | |
994 | ||
995 | raw_spin_unlock_irq(&logbuf_lock); | |
996 | if (copy_to_user(buf + len, text, textlen)) | |
997 | len = -EFAULT; | |
998 | else | |
999 | len += textlen; | |
1000 | raw_spin_lock_irq(&logbuf_lock); | |
1001 | ||
1002 | if (seq < log_first_seq) { | |
1003 | /* messages are gone, move to next one */ | |
1004 | seq = log_first_seq; | |
1005 | idx = log_first_idx; | |
1006 | } | |
1007 | } | |
1008 | } | |
1009 | ||
1010 | if (clear) { | |
1011 | clear_seq = log_next_seq; | |
1012 | clear_idx = log_next_idx; | |
1013 | } | |
1014 | raw_spin_unlock_irq(&logbuf_lock); | |
1015 | ||
1016 | kfree(text); | |
1017 | return len; | |
1018 | } | |
1019 | ||
00234592 | 1020 | int do_syslog(int type, char __user *buf, int len, bool from_file) |
1da177e4 | 1021 | { |
7ff9554b KS |
1022 | bool clear = false; |
1023 | static int saved_console_loglevel = -1; | |
ee24aebf | 1024 | int error; |
1da177e4 | 1025 | |
ee24aebf LT |
1026 | error = check_syslog_permissions(type, from_file); |
1027 | if (error) | |
1028 | goto out; | |
12b3052c EP |
1029 | |
1030 | error = security_syslog(type); | |
1da177e4 LT |
1031 | if (error) |
1032 | return error; | |
1033 | ||
1034 | switch (type) { | |
d78ca3cd | 1035 | case SYSLOG_ACTION_CLOSE: /* Close log */ |
1da177e4 | 1036 | break; |
d78ca3cd | 1037 | case SYSLOG_ACTION_OPEN: /* Open log */ |
1da177e4 | 1038 | break; |
d78ca3cd | 1039 | case SYSLOG_ACTION_READ: /* Read from log */ |
1da177e4 LT |
1040 | error = -EINVAL; |
1041 | if (!buf || len < 0) | |
1042 | goto out; | |
1043 | error = 0; | |
1044 | if (!len) | |
1045 | goto out; | |
1046 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1047 | error = -EFAULT; | |
1048 | goto out; | |
1049 | } | |
40dc5651 | 1050 | error = wait_event_interruptible(log_wait, |
7ff9554b | 1051 | syslog_seq != log_next_seq); |
cb424ffe | 1052 | if (error) |
1da177e4 | 1053 | goto out; |
7ff9554b | 1054 | error = syslog_print(buf, len); |
1da177e4 | 1055 | break; |
d78ca3cd KC |
1056 | /* Read/clear last kernel messages */ |
1057 | case SYSLOG_ACTION_READ_CLEAR: | |
7ff9554b | 1058 | clear = true; |
1da177e4 | 1059 | /* FALL THRU */ |
d78ca3cd KC |
1060 | /* Read last kernel messages */ |
1061 | case SYSLOG_ACTION_READ_ALL: | |
1da177e4 LT |
1062 | error = -EINVAL; |
1063 | if (!buf || len < 0) | |
1064 | goto out; | |
1065 | error = 0; | |
1066 | if (!len) | |
1067 | goto out; | |
1068 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1069 | error = -EFAULT; | |
1070 | goto out; | |
1071 | } | |
7ff9554b | 1072 | error = syslog_print_all(buf, len, clear); |
1da177e4 | 1073 | break; |
d78ca3cd KC |
1074 | /* Clear ring buffer */ |
1075 | case SYSLOG_ACTION_CLEAR: | |
7ff9554b | 1076 | syslog_print_all(NULL, 0, true); |
4661e356 | 1077 | break; |
d78ca3cd KC |
1078 | /* Disable logging to console */ |
1079 | case SYSLOG_ACTION_CONSOLE_OFF: | |
1aaad49e FP |
1080 | if (saved_console_loglevel == -1) |
1081 | saved_console_loglevel = console_loglevel; | |
1da177e4 LT |
1082 | console_loglevel = minimum_console_loglevel; |
1083 | break; | |
d78ca3cd KC |
1084 | /* Enable logging to console */ |
1085 | case SYSLOG_ACTION_CONSOLE_ON: | |
1aaad49e FP |
1086 | if (saved_console_loglevel != -1) { |
1087 | console_loglevel = saved_console_loglevel; | |
1088 | saved_console_loglevel = -1; | |
1089 | } | |
1da177e4 | 1090 | break; |
d78ca3cd KC |
1091 | /* Set level of messages printed to console */ |
1092 | case SYSLOG_ACTION_CONSOLE_LEVEL: | |
1da177e4 LT |
1093 | error = -EINVAL; |
1094 | if (len < 1 || len > 8) | |
1095 | goto out; | |
1096 | if (len < minimum_console_loglevel) | |
1097 | len = minimum_console_loglevel; | |
1098 | console_loglevel = len; | |
1aaad49e FP |
1099 | /* Implicitly re-enable logging to console */ |
1100 | saved_console_loglevel = -1; | |
1da177e4 LT |
1101 | error = 0; |
1102 | break; | |
d78ca3cd KC |
1103 | /* Number of chars in the log buffer */ |
1104 | case SYSLOG_ACTION_SIZE_UNREAD: | |
7ff9554b KS |
1105 | raw_spin_lock_irq(&logbuf_lock); |
1106 | if (syslog_seq < log_first_seq) { | |
1107 | /* messages are gone, move to first one */ | |
1108 | syslog_seq = log_first_seq; | |
1109 | syslog_idx = log_first_idx; | |
1110 | } | |
1111 | if (from_file) { | |
1112 | /* | |
1113 | * Short-cut for poll(/"proc/kmsg") which simply checks | |
1114 | * for pending data, not the size; return the count of | |
1115 | * records, not the length. | |
1116 | */ | |
1117 | error = log_next_idx - syslog_idx; | |
1118 | } else { | |
1119 | u64 seq; | |
1120 | u32 idx; | |
1121 | ||
1122 | error = 0; | |
1123 | seq = syslog_seq; | |
1124 | idx = syslog_idx; | |
1125 | while (seq < log_next_seq) { | |
3ce9a7c0 KS |
1126 | struct log *msg = log_from_idx(idx); |
1127 | ||
1128 | error += msg_print_text(msg, true, NULL, 0); | |
7ff9554b KS |
1129 | idx = log_next(idx); |
1130 | seq++; | |
1131 | } | |
1132 | } | |
1133 | raw_spin_unlock_irq(&logbuf_lock); | |
1da177e4 | 1134 | break; |
d78ca3cd KC |
1135 | /* Size of the log buffer */ |
1136 | case SYSLOG_ACTION_SIZE_BUFFER: | |
1da177e4 LT |
1137 | error = log_buf_len; |
1138 | break; | |
1139 | default: | |
1140 | error = -EINVAL; | |
1141 | break; | |
1142 | } | |
1143 | out: | |
1144 | return error; | |
1145 | } | |
1146 | ||
1e7bfb21 | 1147 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
1da177e4 | 1148 | { |
00234592 | 1149 | return do_syslog(type, buf, len, SYSLOG_FROM_CALL); |
1da177e4 LT |
1150 | } |
1151 | ||
67fc4e0c JW |
1152 | #ifdef CONFIG_KGDB_KDB |
1153 | /* kdb dmesg command needs access to the syslog buffer. do_syslog() | |
1154 | * uses locks so it cannot be used during debugging. Just tell kdb | |
1155 | * where the start and end of the physical and logical logs are. This | |
1156 | * is equivalent to do_syslog(3). | |
1157 | */ | |
1158 | void kdb_syslog_data(char *syslog_data[4]) | |
1159 | { | |
1160 | syslog_data[0] = log_buf; | |
1161 | syslog_data[1] = log_buf + log_buf_len; | |
7ff9554b KS |
1162 | syslog_data[2] = log_buf + log_first_idx; |
1163 | syslog_data[3] = log_buf + log_next_idx; | |
67fc4e0c JW |
1164 | } |
1165 | #endif /* CONFIG_KGDB_KDB */ | |
1166 | ||
2329abfa | 1167 | static bool __read_mostly ignore_loglevel; |
79290822 | 1168 | |
99eea6a1 | 1169 | static int __init ignore_loglevel_setup(char *str) |
79290822 IM |
1170 | { |
1171 | ignore_loglevel = 1; | |
1172 | printk(KERN_INFO "debug: ignoring loglevel setting.\n"); | |
1173 | ||
c4772d99 | 1174 | return 0; |
79290822 IM |
1175 | } |
1176 | ||
c4772d99 | 1177 | early_param("ignore_loglevel", ignore_loglevel_setup); |
29d4d6df | 1178 | module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); |
0eca6b7c YZ |
1179 | MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to" |
1180 | "print all kernel messages to the console."); | |
79290822 | 1181 | |
1da177e4 LT |
1182 | /* |
1183 | * Call the console drivers, asking them to write out | |
1184 | * log_buf[start] to log_buf[end - 1]. | |
ac751efa | 1185 | * The console_lock must be held. |
1da177e4 | 1186 | */ |
7ff9554b | 1187 | static void call_console_drivers(int level, const char *text, size_t len) |
1da177e4 | 1188 | { |
7ff9554b | 1189 | struct console *con; |
1da177e4 | 1190 | |
7ff9554b KS |
1191 | trace_console(text, 0, len, len); |
1192 | ||
1193 | if (level >= console_loglevel && !ignore_loglevel) | |
1194 | return; | |
1195 | if (!console_drivers) | |
1196 | return; | |
1197 | ||
1198 | for_each_console(con) { | |
1199 | if (exclusive_console && con != exclusive_console) | |
1200 | continue; | |
1201 | if (!(con->flags & CON_ENABLED)) | |
1202 | continue; | |
1203 | if (!con->write) | |
1204 | continue; | |
1205 | if (!cpu_online(smp_processor_id()) && | |
1206 | !(con->flags & CON_ANYTIME)) | |
1207 | continue; | |
1208 | con->write(con, text, len); | |
1209 | } | |
1da177e4 LT |
1210 | } |
1211 | ||
1212 | /* | |
1213 | * Zap console related locks when oopsing. Only zap at most once | |
1214 | * every 10 seconds, to leave time for slow consoles to print a | |
1215 | * full oops. | |
1216 | */ | |
1217 | static void zap_locks(void) | |
1218 | { | |
1219 | static unsigned long oops_timestamp; | |
1220 | ||
1221 | if (time_after_eq(jiffies, oops_timestamp) && | |
40dc5651 | 1222 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
1da177e4 LT |
1223 | return; |
1224 | ||
1225 | oops_timestamp = jiffies; | |
1226 | ||
94d24fc4 | 1227 | debug_locks_off(); |
1da177e4 | 1228 | /* If a crash is occurring, make sure we can't deadlock */ |
07354eb1 | 1229 | raw_spin_lock_init(&logbuf_lock); |
1da177e4 | 1230 | /* And make sure that we print immediately */ |
5b8c4f23 | 1231 | sema_init(&console_sem, 1); |
1da177e4 LT |
1232 | } |
1233 | ||
76a8ad29 ME |
1234 | /* Check if we have any console registered that can be called early in boot. */ |
1235 | static int have_callable_console(void) | |
1236 | { | |
1237 | struct console *con; | |
1238 | ||
4d091611 | 1239 | for_each_console(con) |
76a8ad29 ME |
1240 | if (con->flags & CON_ANYTIME) |
1241 | return 1; | |
1242 | ||
1243 | return 0; | |
1244 | } | |
1245 | ||
266c2e0a LT |
1246 | /* |
1247 | * Can we actually use the console at this time on this cpu? | |
1248 | * | |
1249 | * Console drivers may assume that per-cpu resources have | |
1250 | * been allocated. So unless they're explicitly marked as | |
1251 | * being able to cope (CON_ANYTIME) don't call them until | |
1252 | * this CPU is officially up. | |
1253 | */ | |
1254 | static inline int can_use_console(unsigned int cpu) | |
1255 | { | |
1256 | return cpu_online(cpu) || have_callable_console(); | |
1257 | } | |
1258 | ||
1259 | /* | |
1260 | * Try to get console ownership to actually show the kernel | |
1261 | * messages from a 'printk'. Return true (and with the | |
ac751efa | 1262 | * console_lock held, and 'console_locked' set) if it |
266c2e0a LT |
1263 | * is successful, false otherwise. |
1264 | * | |
1265 | * This gets called with the 'logbuf_lock' spinlock held and | |
1266 | * interrupts disabled. It should return with 'lockbuf_lock' | |
1267 | * released but interrupts still disabled. | |
1268 | */ | |
ac751efa | 1269 | static int console_trylock_for_printk(unsigned int cpu) |
8155c02a | 1270 | __releases(&logbuf_lock) |
266c2e0a | 1271 | { |
0b5e1c52 | 1272 | int retval = 0, wake = 0; |
266c2e0a | 1273 | |
ac751efa | 1274 | if (console_trylock()) { |
093a07e2 LT |
1275 | retval = 1; |
1276 | ||
1277 | /* | |
1278 | * If we can't use the console, we need to release | |
1279 | * the console semaphore by hand to avoid flushing | |
1280 | * the buffer. We need to hold the console semaphore | |
1281 | * in order to do this test safely. | |
1282 | */ | |
1283 | if (!can_use_console(cpu)) { | |
1284 | console_locked = 0; | |
0b5e1c52 | 1285 | wake = 1; |
093a07e2 LT |
1286 | retval = 0; |
1287 | } | |
1288 | } | |
7ff9554b | 1289 | logbuf_cpu = UINT_MAX; |
0b5e1c52 PZ |
1290 | if (wake) |
1291 | up(&console_sem); | |
07354eb1 | 1292 | raw_spin_unlock(&logbuf_lock); |
266c2e0a LT |
1293 | return retval; |
1294 | } | |
32a76006 | 1295 | |
af91322e DY |
1296 | int printk_delay_msec __read_mostly; |
1297 | ||
1298 | static inline void printk_delay(void) | |
1299 | { | |
1300 | if (unlikely(printk_delay_msec)) { | |
1301 | int m = printk_delay_msec; | |
1302 | ||
1303 | while (m--) { | |
1304 | mdelay(1); | |
1305 | touch_nmi_watchdog(); | |
1306 | } | |
1307 | } | |
1308 | } | |
1309 | ||
084681d1 KS |
1310 | /* |
1311 | * Continuation lines are buffered, and not committed to the record buffer | |
1312 | * until the line is complete, or a race forces it. The line fragments | |
1313 | * though, are printed immediately to the consoles to ensure everything has | |
1314 | * reached the console in case of a kernel crash. | |
1315 | */ | |
1316 | static struct cont { | |
1317 | char buf[LOG_LINE_MAX]; | |
1318 | size_t len; /* length == 0 means unused buffer */ | |
1319 | size_t cons; /* bytes written to console */ | |
1320 | struct task_struct *owner; /* task of first print*/ | |
1321 | u64 ts_nsec; /* time of first print */ | |
1322 | u8 level; /* log level of first message */ | |
1323 | u8 facility; /* log level of first message */ | |
1324 | bool flushed:1; /* buffer sealed and committed */ | |
1325 | } cont; | |
1326 | ||
1327 | static void cont_flush(void) | |
1328 | { | |
1329 | if (cont.flushed) | |
1330 | return; | |
1331 | if (cont.len == 0) | |
1332 | return; | |
1333 | ||
1334 | log_store(cont.facility, cont.level, LOG_NOCONS, cont.ts_nsec, | |
1335 | NULL, 0, cont.buf, cont.len); | |
1336 | ||
1337 | cont.flushed = true; | |
1338 | } | |
1339 | ||
1340 | static bool cont_add(int facility, int level, const char *text, size_t len) | |
1341 | { | |
1342 | if (cont.len && cont.flushed) | |
1343 | return false; | |
1344 | ||
1345 | if (cont.len + len > sizeof(cont.buf)) { | |
1346 | cont_flush(); | |
1347 | return false; | |
1348 | } | |
1349 | ||
1350 | if (!cont.len) { | |
1351 | cont.facility = facility; | |
1352 | cont.level = level; | |
1353 | cont.owner = current; | |
1354 | cont.ts_nsec = local_clock(); | |
1355 | cont.cons = 0; | |
1356 | cont.flushed = false; | |
1357 | } | |
1358 | ||
1359 | memcpy(cont.buf + cont.len, text, len); | |
1360 | cont.len += len; | |
1361 | return true; | |
1362 | } | |
1363 | ||
1364 | static size_t cont_print_text(char *text, size_t size) | |
1365 | { | |
1366 | size_t textlen = 0; | |
1367 | size_t len; | |
1368 | ||
1369 | if (cont.cons == 0) { | |
1370 | textlen += print_time(cont.ts_nsec, text); | |
1371 | size -= textlen; | |
1372 | } | |
1373 | ||
1374 | len = cont.len - cont.cons; | |
1375 | if (len > 0) { | |
1376 | if (len+1 > size) | |
1377 | len = size-1; | |
1378 | memcpy(text + textlen, cont.buf + cont.cons, len); | |
1379 | textlen += len; | |
1380 | cont.cons = cont.len; | |
1381 | } | |
1382 | ||
1383 | if (cont.flushed) { | |
1384 | text[textlen++] = '\n'; | |
1385 | /* got everything, release buffer */ | |
1386 | cont.len = 0; | |
1387 | } | |
1388 | return textlen; | |
1389 | } | |
1390 | ||
7ff9554b KS |
1391 | asmlinkage int vprintk_emit(int facility, int level, |
1392 | const char *dict, size_t dictlen, | |
1393 | const char *fmt, va_list args) | |
1da177e4 | 1394 | { |
7ff9554b | 1395 | static int recursion_bug; |
7ff9554b KS |
1396 | static char textbuf[LOG_LINE_MAX]; |
1397 | char *text = textbuf; | |
c313af14 | 1398 | size_t text_len; |
ac60ad74 | 1399 | unsigned long flags; |
32a76006 | 1400 | int this_cpu; |
7ff9554b | 1401 | bool newline = false; |
5c5d5ca5 | 1402 | bool prefix = false; |
7ff9554b | 1403 | int printed_len = 0; |
1da177e4 | 1404 | |
bfe8df3d | 1405 | boot_delay_msec(); |
af91322e | 1406 | printk_delay(); |
bfe8df3d | 1407 | |
1da177e4 | 1408 | /* This stops the holder of console_sem just where we want him */ |
1a9a8aef | 1409 | local_irq_save(flags); |
32a76006 IM |
1410 | this_cpu = smp_processor_id(); |
1411 | ||
1412 | /* | |
1413 | * Ouch, printk recursed into itself! | |
1414 | */ | |
7ff9554b | 1415 | if (unlikely(logbuf_cpu == this_cpu)) { |
32a76006 IM |
1416 | /* |
1417 | * If a crash is occurring during printk() on this CPU, | |
1418 | * then try to get the crash message out but make sure | |
1419 | * we can't deadlock. Otherwise just return to avoid the | |
1420 | * recursion and return - but flag the recursion so that | |
1421 | * it can be printed at the next appropriate moment: | |
1422 | */ | |
94d24fc4 | 1423 | if (!oops_in_progress && !lockdep_recursing(current)) { |
3b8945e8 | 1424 | recursion_bug = 1; |
32a76006 IM |
1425 | goto out_restore_irqs; |
1426 | } | |
1427 | zap_locks(); | |
1428 | } | |
1429 | ||
a0f1ccfd | 1430 | lockdep_off(); |
07354eb1 | 1431 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 1432 | logbuf_cpu = this_cpu; |
1da177e4 | 1433 | |
3b8945e8 | 1434 | if (recursion_bug) { |
7ff9554b KS |
1435 | static const char recursion_msg[] = |
1436 | "BUG: recent printk recursion!"; | |
1437 | ||
3b8945e8 | 1438 | recursion_bug = 0; |
7ff9554b KS |
1439 | printed_len += strlen(recursion_msg); |
1440 | /* emit KERN_CRIT message */ | |
084681d1 KS |
1441 | log_store(0, 2, LOG_DEFAULT, 0, |
1442 | NULL, 0, recursion_msg, printed_len); | |
32a76006 | 1443 | } |
1da177e4 | 1444 | |
7ff9554b KS |
1445 | /* |
1446 | * The printf needs to come first; we need the syslog | |
1447 | * prefix which might be passed-in as a parameter. | |
1448 | */ | |
c313af14 | 1449 | text_len = vscnprintf(text, sizeof(textbuf), fmt, args); |
5fd29d6c | 1450 | |
7ff9554b | 1451 | /* mark and strip a trailing newline */ |
c313af14 KS |
1452 | if (text_len && text[text_len-1] == '\n') { |
1453 | text_len--; | |
7ff9554b KS |
1454 | newline = true; |
1455 | } | |
9d90c8d9 | 1456 | |
c313af14 | 1457 | /* strip syslog prefix and extract log level or control flags */ |
7ff9554b KS |
1458 | if (text[0] == '<' && text[1] && text[2] == '>') { |
1459 | switch (text[1]) { | |
1460 | case '0' ... '7': | |
1461 | if (level == -1) | |
1462 | level = text[1] - '0'; | |
7ff9554b | 1463 | case 'd': /* KERN_DEFAULT */ |
5c5d5ca5 KS |
1464 | prefix = true; |
1465 | case 'c': /* KERN_CONT */ | |
7ff9554b | 1466 | text += 3; |
c313af14 | 1467 | text_len -= 3; |
5fd29d6c LT |
1468 | } |
1469 | } | |
1470 | ||
c313af14 KS |
1471 | if (level == -1) |
1472 | level = default_message_loglevel; | |
9d90c8d9 | 1473 | |
c313af14 KS |
1474 | if (dict) { |
1475 | prefix = true; | |
1476 | newline = true; | |
7ff9554b | 1477 | } |
ac60ad74 | 1478 | |
c313af14 | 1479 | if (!newline) { |
084681d1 KS |
1480 | /* |
1481 | * Flush the conflicting buffer. An earlier newline was missing, | |
1482 | * or another task also prints continuation lines. | |
1483 | */ | |
1484 | if (cont.len && (prefix || cont.owner != current)) | |
1485 | cont_flush(); | |
c313af14 | 1486 | |
084681d1 KS |
1487 | /* buffer line if possible, otherwise store it right away */ |
1488 | if (!cont_add(facility, level, text, text_len)) | |
1489 | log_store(facility, level, LOG_DEFAULT, 0, | |
1490 | dict, dictlen, text, text_len); | |
5c5d5ca5 | 1491 | } else { |
084681d1 | 1492 | bool stored = false; |
c313af14 | 1493 | |
084681d1 | 1494 | /* |
d3620822 SR |
1495 | * If an earlier newline was missing and it was the same task, |
1496 | * either merge it with the current buffer and flush, or if | |
1497 | * there was a race with interrupts (prefix == true) then just | |
1498 | * flush it out and store this line separately. | |
084681d1 | 1499 | */ |
084681d1 | 1500 | if (cont.len && cont.owner == current) { |
d3620822 SR |
1501 | if (!prefix) |
1502 | stored = cont_add(facility, level, text, text_len); | |
084681d1 | 1503 | cont_flush(); |
c313af14 | 1504 | } |
084681d1 KS |
1505 | |
1506 | if (!stored) | |
1507 | log_store(facility, level, LOG_DEFAULT, 0, | |
1508 | dict, dictlen, text, text_len); | |
1da177e4 | 1509 | } |
084681d1 | 1510 | printed_len += text_len; |
1da177e4 | 1511 | |
266c2e0a | 1512 | /* |
7ff9554b KS |
1513 | * Try to acquire and then immediately release the console semaphore. |
1514 | * The release will print out buffers and wake up /dev/kmsg and syslog() | |
1515 | * users. | |
266c2e0a | 1516 | * |
7ff9554b KS |
1517 | * The console_trylock_for_printk() function will release 'logbuf_lock' |
1518 | * regardless of whether it actually gets the console semaphore or not. | |
266c2e0a | 1519 | */ |
ac751efa TH |
1520 | if (console_trylock_for_printk(this_cpu)) |
1521 | console_unlock(); | |
76a8ad29 | 1522 | |
266c2e0a | 1523 | lockdep_on(); |
32a76006 | 1524 | out_restore_irqs: |
1a9a8aef | 1525 | local_irq_restore(flags); |
76a8ad29 | 1526 | |
1da177e4 LT |
1527 | return printed_len; |
1528 | } | |
7ff9554b KS |
1529 | EXPORT_SYMBOL(vprintk_emit); |
1530 | ||
1531 | asmlinkage int vprintk(const char *fmt, va_list args) | |
1532 | { | |
1533 | return vprintk_emit(0, -1, NULL, 0, fmt, args); | |
1534 | } | |
1da177e4 LT |
1535 | EXPORT_SYMBOL(vprintk); |
1536 | ||
7ff9554b KS |
1537 | asmlinkage int printk_emit(int facility, int level, |
1538 | const char *dict, size_t dictlen, | |
1539 | const char *fmt, ...) | |
1540 | { | |
1541 | va_list args; | |
1542 | int r; | |
1543 | ||
1544 | va_start(args, fmt); | |
1545 | r = vprintk_emit(facility, level, dict, dictlen, fmt, args); | |
1546 | va_end(args); | |
1547 | ||
1548 | return r; | |
1549 | } | |
1550 | EXPORT_SYMBOL(printk_emit); | |
1551 | ||
1552 | /** | |
1553 | * printk - print a kernel message | |
1554 | * @fmt: format string | |
1555 | * | |
1556 | * This is printk(). It can be called from any context. We want it to work. | |
1557 | * | |
1558 | * We try to grab the console_lock. If we succeed, it's easy - we log the | |
1559 | * output and call the console drivers. If we fail to get the semaphore, we | |
1560 | * place the output into the log buffer and return. The current holder of | |
1561 | * the console_sem will notice the new output in console_unlock(); and will | |
1562 | * send it to the consoles before releasing the lock. | |
1563 | * | |
1564 | * One effect of this deferred printing is that code which calls printk() and | |
1565 | * then changes console_loglevel may break. This is because console_loglevel | |
1566 | * is inspected when the actual printing occurs. | |
1567 | * | |
1568 | * See also: | |
1569 | * printf(3) | |
1570 | * | |
1571 | * See the vsnprintf() documentation for format string extensions over C99. | |
1572 | */ | |
1573 | asmlinkage int printk(const char *fmt, ...) | |
1574 | { | |
1575 | va_list args; | |
1576 | int r; | |
1577 | ||
1578 | #ifdef CONFIG_KGDB_KDB | |
1579 | if (unlikely(kdb_trap_printk)) { | |
1580 | va_start(args, fmt); | |
1581 | r = vkdb_printf(fmt, args); | |
1582 | va_end(args); | |
1583 | return r; | |
1584 | } | |
1585 | #endif | |
1586 | va_start(args, fmt); | |
1587 | r = vprintk_emit(0, -1, NULL, 0, fmt, args); | |
1588 | va_end(args); | |
1589 | ||
1590 | return r; | |
1591 | } | |
1592 | EXPORT_SYMBOL(printk); | |
7f3a781d | 1593 | |
d59745ce MM |
1594 | #else |
1595 | ||
7f3a781d | 1596 | #define LOG_LINE_MAX 0 |
084681d1 KS |
1597 | static struct cont { |
1598 | size_t len; | |
1599 | size_t cons; | |
1600 | u8 level; | |
1601 | bool flushed:1; | |
1602 | } cont; | |
7f3a781d KS |
1603 | static struct log *log_from_idx(u32 idx) { return NULL; } |
1604 | static u32 log_next(u32 idx) { return 0; } | |
7f3a781d | 1605 | static void call_console_drivers(int level, const char *text, size_t len) {} |
3ce9a7c0 KS |
1606 | static size_t msg_print_text(const struct log *msg, bool syslog, |
1607 | char *buf, size_t size) { return 0; } | |
084681d1 | 1608 | static size_t cont_print_text(char *text, size_t size) { return 0; } |
d59745ce | 1609 | |
7f3a781d | 1610 | #endif /* CONFIG_PRINTK */ |
d59745ce | 1611 | |
f7511d5f ST |
1612 | static int __add_preferred_console(char *name, int idx, char *options, |
1613 | char *brl_options) | |
1614 | { | |
1615 | struct console_cmdline *c; | |
1616 | int i; | |
1617 | ||
1618 | /* | |
1619 | * See if this tty is not yet registered, and | |
1620 | * if we have a slot free. | |
1621 | */ | |
1622 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) | |
1623 | if (strcmp(console_cmdline[i].name, name) == 0 && | |
1624 | console_cmdline[i].index == idx) { | |
1625 | if (!brl_options) | |
1626 | selected_console = i; | |
1627 | return 0; | |
1628 | } | |
1629 | if (i == MAX_CMDLINECONSOLES) | |
1630 | return -E2BIG; | |
1631 | if (!brl_options) | |
1632 | selected_console = i; | |
1633 | c = &console_cmdline[i]; | |
1634 | strlcpy(c->name, name, sizeof(c->name)); | |
1635 | c->options = options; | |
1636 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE | |
1637 | c->brl_options = brl_options; | |
1638 | #endif | |
1639 | c->index = idx; | |
1640 | return 0; | |
1641 | } | |
2ea1c539 JB |
1642 | /* |
1643 | * Set up a list of consoles. Called from init/main.c | |
1644 | */ | |
1645 | static int __init console_setup(char *str) | |
1646 | { | |
eaa944af | 1647 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ |
f7511d5f | 1648 | char *s, *options, *brl_options = NULL; |
2ea1c539 JB |
1649 | int idx; |
1650 | ||
f7511d5f ST |
1651 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
1652 | if (!memcmp(str, "brl,", 4)) { | |
1653 | brl_options = ""; | |
1654 | str += 4; | |
1655 | } else if (!memcmp(str, "brl=", 4)) { | |
1656 | brl_options = str + 4; | |
1657 | str = strchr(brl_options, ','); | |
1658 | if (!str) { | |
1659 | printk(KERN_ERR "need port name after brl=\n"); | |
1660 | return 1; | |
1661 | } | |
1662 | *(str++) = 0; | |
1663 | } | |
1664 | #endif | |
1665 | ||
2ea1c539 JB |
1666 | /* |
1667 | * Decode str into name, index, options. | |
1668 | */ | |
1669 | if (str[0] >= '0' && str[0] <= '9') { | |
eaa944af YL |
1670 | strcpy(buf, "ttyS"); |
1671 | strncpy(buf + 4, str, sizeof(buf) - 5); | |
2ea1c539 | 1672 | } else { |
eaa944af | 1673 | strncpy(buf, str, sizeof(buf) - 1); |
2ea1c539 | 1674 | } |
eaa944af | 1675 | buf[sizeof(buf) - 1] = 0; |
2ea1c539 JB |
1676 | if ((options = strchr(str, ',')) != NULL) |
1677 | *(options++) = 0; | |
1678 | #ifdef __sparc__ | |
1679 | if (!strcmp(str, "ttya")) | |
eaa944af | 1680 | strcpy(buf, "ttyS0"); |
2ea1c539 | 1681 | if (!strcmp(str, "ttyb")) |
eaa944af | 1682 | strcpy(buf, "ttyS1"); |
2ea1c539 | 1683 | #endif |
eaa944af | 1684 | for (s = buf; *s; s++) |
2ea1c539 JB |
1685 | if ((*s >= '0' && *s <= '9') || *s == ',') |
1686 | break; | |
1687 | idx = simple_strtoul(s, NULL, 10); | |
1688 | *s = 0; | |
1689 | ||
f7511d5f | 1690 | __add_preferred_console(buf, idx, options, brl_options); |
9e124fe1 | 1691 | console_set_on_cmdline = 1; |
2ea1c539 JB |
1692 | return 1; |
1693 | } | |
1694 | __setup("console=", console_setup); | |
1695 | ||
3c0547ba MM |
1696 | /** |
1697 | * add_preferred_console - add a device to the list of preferred consoles. | |
ddad86c2 MW |
1698 | * @name: device name |
1699 | * @idx: device index | |
1700 | * @options: options for this console | |
3c0547ba MM |
1701 | * |
1702 | * The last preferred console added will be used for kernel messages | |
1703 | * and stdin/out/err for init. Normally this is used by console_setup | |
1704 | * above to handle user-supplied console arguments; however it can also | |
1705 | * be used by arch-specific code either to override the user or more | |
1706 | * commonly to provide a default console (ie from PROM variables) when | |
1707 | * the user has not supplied one. | |
1708 | */ | |
fb445ee5 | 1709 | int add_preferred_console(char *name, int idx, char *options) |
3c0547ba | 1710 | { |
f7511d5f | 1711 | return __add_preferred_console(name, idx, options, NULL); |
3c0547ba MM |
1712 | } |
1713 | ||
b6b1d877 | 1714 | int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options) |
18a8bd94 YL |
1715 | { |
1716 | struct console_cmdline *c; | |
1717 | int i; | |
1718 | ||
1719 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++) | |
1720 | if (strcmp(console_cmdline[i].name, name) == 0 && | |
1721 | console_cmdline[i].index == idx) { | |
1722 | c = &console_cmdline[i]; | |
f735295b | 1723 | strlcpy(c->name, name_new, sizeof(c->name)); |
18a8bd94 YL |
1724 | c->name[sizeof(c->name) - 1] = 0; |
1725 | c->options = options; | |
1726 | c->index = idx_new; | |
1727 | return i; | |
1728 | } | |
1729 | /* not found */ | |
1730 | return -1; | |
1731 | } | |
1732 | ||
2329abfa | 1733 | bool console_suspend_enabled = 1; |
8f4ce8c3 AS |
1734 | EXPORT_SYMBOL(console_suspend_enabled); |
1735 | ||
1736 | static int __init console_suspend_disable(char *str) | |
1737 | { | |
1738 | console_suspend_enabled = 0; | |
1739 | return 1; | |
1740 | } | |
1741 | __setup("no_console_suspend", console_suspend_disable); | |
134620f7 YZ |
1742 | module_param_named(console_suspend, console_suspend_enabled, |
1743 | bool, S_IRUGO | S_IWUSR); | |
1744 | MODULE_PARM_DESC(console_suspend, "suspend console during suspend" | |
1745 | " and hibernate operations"); | |
8f4ce8c3 | 1746 | |
557240b4 LT |
1747 | /** |
1748 | * suspend_console - suspend the console subsystem | |
1749 | * | |
1750 | * This disables printk() while we go into suspend states | |
1751 | */ | |
1752 | void suspend_console(void) | |
1753 | { | |
8f4ce8c3 AS |
1754 | if (!console_suspend_enabled) |
1755 | return; | |
0d63081d | 1756 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
ac751efa | 1757 | console_lock(); |
557240b4 | 1758 | console_suspended = 1; |
403f3075 | 1759 | up(&console_sem); |
557240b4 LT |
1760 | } |
1761 | ||
1762 | void resume_console(void) | |
1763 | { | |
8f4ce8c3 AS |
1764 | if (!console_suspend_enabled) |
1765 | return; | |
403f3075 | 1766 | down(&console_sem); |
557240b4 | 1767 | console_suspended = 0; |
ac751efa | 1768 | console_unlock(); |
557240b4 LT |
1769 | } |
1770 | ||
034260d6 KC |
1771 | /** |
1772 | * console_cpu_notify - print deferred console messages after CPU hotplug | |
1773 | * @self: notifier struct | |
1774 | * @action: CPU hotplug event | |
1775 | * @hcpu: unused | |
1776 | * | |
1777 | * If printk() is called from a CPU that is not online yet, the messages | |
1778 | * will be spooled but will not show up on the console. This function is | |
1779 | * called when a new CPU comes online (or fails to come up), and ensures | |
1780 | * that any such output gets printed. | |
1781 | */ | |
1782 | static int __cpuinit console_cpu_notify(struct notifier_block *self, | |
1783 | unsigned long action, void *hcpu) | |
1784 | { | |
1785 | switch (action) { | |
1786 | case CPU_ONLINE: | |
1787 | case CPU_DEAD: | |
1788 | case CPU_DYING: | |
1789 | case CPU_DOWN_FAILED: | |
1790 | case CPU_UP_CANCELED: | |
ac751efa TH |
1791 | console_lock(); |
1792 | console_unlock(); | |
034260d6 KC |
1793 | } |
1794 | return NOTIFY_OK; | |
1795 | } | |
1796 | ||
1da177e4 | 1797 | /** |
ac751efa | 1798 | * console_lock - lock the console system for exclusive use. |
1da177e4 | 1799 | * |
ac751efa | 1800 | * Acquires a lock which guarantees that the caller has |
1da177e4 LT |
1801 | * exclusive access to the console system and the console_drivers list. |
1802 | * | |
1803 | * Can sleep, returns nothing. | |
1804 | */ | |
ac751efa | 1805 | void console_lock(void) |
1da177e4 | 1806 | { |
8abd8e29 | 1807 | BUG_ON(in_interrupt()); |
1da177e4 | 1808 | down(&console_sem); |
403f3075 AH |
1809 | if (console_suspended) |
1810 | return; | |
1da177e4 LT |
1811 | console_locked = 1; |
1812 | console_may_schedule = 1; | |
1813 | } | |
ac751efa | 1814 | EXPORT_SYMBOL(console_lock); |
1da177e4 | 1815 | |
ac751efa TH |
1816 | /** |
1817 | * console_trylock - try to lock the console system for exclusive use. | |
1818 | * | |
1819 | * Tried to acquire a lock which guarantees that the caller has | |
1820 | * exclusive access to the console system and the console_drivers list. | |
1821 | * | |
1822 | * returns 1 on success, and 0 on failure to acquire the lock. | |
1823 | */ | |
1824 | int console_trylock(void) | |
1da177e4 LT |
1825 | { |
1826 | if (down_trylock(&console_sem)) | |
ac751efa | 1827 | return 0; |
403f3075 AH |
1828 | if (console_suspended) { |
1829 | up(&console_sem); | |
ac751efa | 1830 | return 0; |
403f3075 | 1831 | } |
1da177e4 LT |
1832 | console_locked = 1; |
1833 | console_may_schedule = 0; | |
ac751efa | 1834 | return 1; |
1da177e4 | 1835 | } |
ac751efa | 1836 | EXPORT_SYMBOL(console_trylock); |
1da177e4 LT |
1837 | |
1838 | int is_console_locked(void) | |
1839 | { | |
1840 | return console_locked; | |
1841 | } | |
1da177e4 | 1842 | |
3ccf3e83 | 1843 | /* |
7ff9554b | 1844 | * Delayed printk version, for scheduler-internal messages: |
3ccf3e83 PZ |
1845 | */ |
1846 | #define PRINTK_BUF_SIZE 512 | |
1847 | ||
1848 | #define PRINTK_PENDING_WAKEUP 0x01 | |
1849 | #define PRINTK_PENDING_SCHED 0x02 | |
1850 | ||
b845b517 | 1851 | static DEFINE_PER_CPU(int, printk_pending); |
3ccf3e83 | 1852 | static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf); |
b845b517 PZ |
1853 | |
1854 | void printk_tick(void) | |
e3e8a75d | 1855 | { |
40dc11ff | 1856 | if (__this_cpu_read(printk_pending)) { |
3ccf3e83 PZ |
1857 | int pending = __this_cpu_xchg(printk_pending, 0); |
1858 | if (pending & PRINTK_PENDING_SCHED) { | |
1859 | char *buf = __get_cpu_var(printk_sched_buf); | |
1860 | printk(KERN_WARNING "[sched_delayed] %s", buf); | |
1861 | } | |
1862 | if (pending & PRINTK_PENDING_WAKEUP) | |
1863 | wake_up_interruptible(&log_wait); | |
b845b517 PZ |
1864 | } |
1865 | } | |
1866 | ||
1867 | int printk_needs_cpu(int cpu) | |
1868 | { | |
40dc11ff | 1869 | if (cpu_is_offline(cpu)) |
61ab2544 | 1870 | printk_tick(); |
40dc11ff | 1871 | return __this_cpu_read(printk_pending); |
b845b517 PZ |
1872 | } |
1873 | ||
1874 | void wake_up_klogd(void) | |
1875 | { | |
1876 | if (waitqueue_active(&log_wait)) | |
3ccf3e83 | 1877 | this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); |
e3e8a75d KK |
1878 | } |
1879 | ||
7ff9554b KS |
1880 | /* the next printk record to write to the console */ |
1881 | static u64 console_seq; | |
1882 | static u32 console_idx; | |
1883 | ||
1da177e4 | 1884 | /** |
ac751efa | 1885 | * console_unlock - unlock the console system |
1da177e4 | 1886 | * |
ac751efa | 1887 | * Releases the console_lock which the caller holds on the console system |
1da177e4 LT |
1888 | * and the console driver list. |
1889 | * | |
ac751efa TH |
1890 | * While the console_lock was held, console output may have been buffered |
1891 | * by printk(). If this is the case, console_unlock(); emits | |
1892 | * the output prior to releasing the lock. | |
1da177e4 | 1893 | * |
7f3a781d | 1894 | * If there is output waiting, we wake /dev/kmsg and syslog() users. |
1da177e4 | 1895 | * |
ac751efa | 1896 | * console_unlock(); may be called from any context. |
1da177e4 | 1897 | */ |
ac751efa | 1898 | void console_unlock(void) |
1da177e4 | 1899 | { |
084681d1 | 1900 | static char text[LOG_LINE_MAX]; |
7ff9554b | 1901 | static u64 seen_seq; |
1da177e4 | 1902 | unsigned long flags; |
7ff9554b KS |
1903 | bool wake_klogd = false; |
1904 | bool retry; | |
1da177e4 | 1905 | |
557240b4 | 1906 | if (console_suspended) { |
403f3075 | 1907 | up(&console_sem); |
557240b4 LT |
1908 | return; |
1909 | } | |
78944e54 AD |
1910 | |
1911 | console_may_schedule = 0; | |
1912 | ||
084681d1 KS |
1913 | /* flush buffered message fragment immediately to console */ |
1914 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
1915 | if (cont.len && (cont.cons < cont.len || cont.flushed)) { | |
1916 | size_t len; | |
1917 | ||
1918 | len = cont_print_text(text, sizeof(text)); | |
1919 | raw_spin_unlock(&logbuf_lock); | |
1920 | stop_critical_timings(); | |
1921 | call_console_drivers(cont.level, text, len); | |
1922 | start_critical_timings(); | |
1923 | local_irq_restore(flags); | |
1924 | } else | |
1925 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
1926 | ||
4f2a8d3c | 1927 | again: |
7ff9554b KS |
1928 | for (;;) { |
1929 | struct log *msg; | |
3ce9a7c0 | 1930 | size_t len; |
7ff9554b KS |
1931 | int level; |
1932 | ||
07354eb1 | 1933 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
1934 | if (seen_seq != log_next_seq) { |
1935 | wake_klogd = true; | |
1936 | seen_seq = log_next_seq; | |
1937 | } | |
1938 | ||
1939 | if (console_seq < log_first_seq) { | |
1940 | /* messages are gone, move to first one */ | |
1941 | console_seq = log_first_seq; | |
1942 | console_idx = log_first_idx; | |
1943 | } | |
084681d1 | 1944 | skip: |
7ff9554b KS |
1945 | if (console_seq == log_next_seq) |
1946 | break; | |
1947 | ||
1948 | msg = log_from_idx(console_idx); | |
084681d1 KS |
1949 | if (msg->flags & LOG_NOCONS) { |
1950 | /* | |
1951 | * Skip record we have buffered and already printed | |
1952 | * directly to the console when we received it. | |
1953 | */ | |
1954 | console_idx = log_next(console_idx); | |
1955 | console_seq++; | |
68b6507d KS |
1956 | /* |
1957 | * We will get here again when we register a new | |
1958 | * CON_PRINTBUFFER console. Clear the flag so we | |
1959 | * will properly dump everything later. | |
1960 | */ | |
1961 | msg->flags &= ~LOG_NOCONS; | |
084681d1 KS |
1962 | goto skip; |
1963 | } | |
649e6ee3 | 1964 | |
084681d1 | 1965 | level = msg->level; |
3ce9a7c0 | 1966 | len = msg_print_text(msg, false, text, sizeof(text)); |
7ff9554b KS |
1967 | |
1968 | console_idx = log_next(console_idx); | |
1969 | console_seq++; | |
07354eb1 | 1970 | raw_spin_unlock(&logbuf_lock); |
7ff9554b | 1971 | |
81d68a96 | 1972 | stop_critical_timings(); /* don't trace print latency */ |
7ff9554b | 1973 | call_console_drivers(level, text, len); |
81d68a96 | 1974 | start_critical_timings(); |
1da177e4 LT |
1975 | local_irq_restore(flags); |
1976 | } | |
1977 | console_locked = 0; | |
fe3d8ad3 FT |
1978 | |
1979 | /* Release the exclusive_console once it is used */ | |
1980 | if (unlikely(exclusive_console)) | |
1981 | exclusive_console = NULL; | |
1982 | ||
07354eb1 | 1983 | raw_spin_unlock(&logbuf_lock); |
4f2a8d3c | 1984 | |
0b5e1c52 | 1985 | up(&console_sem); |
4f2a8d3c PZ |
1986 | |
1987 | /* | |
1988 | * Someone could have filled up the buffer again, so re-check if there's | |
1989 | * something to flush. In case we cannot trylock the console_sem again, | |
1990 | * there's a new owner and the console_unlock() from them will do the | |
1991 | * flush, no worries. | |
1992 | */ | |
07354eb1 | 1993 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 1994 | retry = console_seq != log_next_seq; |
09dc3cf9 PZ |
1995 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
1996 | ||
4f2a8d3c PZ |
1997 | if (retry && console_trylock()) |
1998 | goto again; | |
1999 | ||
e3e8a75d KK |
2000 | if (wake_klogd) |
2001 | wake_up_klogd(); | |
1da177e4 | 2002 | } |
ac751efa | 2003 | EXPORT_SYMBOL(console_unlock); |
1da177e4 | 2004 | |
ddad86c2 MW |
2005 | /** |
2006 | * console_conditional_schedule - yield the CPU if required | |
1da177e4 LT |
2007 | * |
2008 | * If the console code is currently allowed to sleep, and | |
2009 | * if this CPU should yield the CPU to another task, do | |
2010 | * so here. | |
2011 | * | |
ac751efa | 2012 | * Must be called within console_lock();. |
1da177e4 LT |
2013 | */ |
2014 | void __sched console_conditional_schedule(void) | |
2015 | { | |
2016 | if (console_may_schedule) | |
2017 | cond_resched(); | |
2018 | } | |
2019 | EXPORT_SYMBOL(console_conditional_schedule); | |
2020 | ||
1da177e4 LT |
2021 | void console_unblank(void) |
2022 | { | |
2023 | struct console *c; | |
2024 | ||
2025 | /* | |
2026 | * console_unblank can no longer be called in interrupt context unless | |
2027 | * oops_in_progress is set to 1.. | |
2028 | */ | |
2029 | if (oops_in_progress) { | |
2030 | if (down_trylock(&console_sem) != 0) | |
2031 | return; | |
2032 | } else | |
ac751efa | 2033 | console_lock(); |
1da177e4 LT |
2034 | |
2035 | console_locked = 1; | |
2036 | console_may_schedule = 0; | |
4d091611 | 2037 | for_each_console(c) |
1da177e4 LT |
2038 | if ((c->flags & CON_ENABLED) && c->unblank) |
2039 | c->unblank(); | |
ac751efa | 2040 | console_unlock(); |
1da177e4 | 2041 | } |
1da177e4 LT |
2042 | |
2043 | /* | |
2044 | * Return the console tty driver structure and its associated index | |
2045 | */ | |
2046 | struct tty_driver *console_device(int *index) | |
2047 | { | |
2048 | struct console *c; | |
2049 | struct tty_driver *driver = NULL; | |
2050 | ||
ac751efa | 2051 | console_lock(); |
4d091611 | 2052 | for_each_console(c) { |
1da177e4 LT |
2053 | if (!c->device) |
2054 | continue; | |
2055 | driver = c->device(c, index); | |
2056 | if (driver) | |
2057 | break; | |
2058 | } | |
ac751efa | 2059 | console_unlock(); |
1da177e4 LT |
2060 | return driver; |
2061 | } | |
2062 | ||
2063 | /* | |
2064 | * Prevent further output on the passed console device so that (for example) | |
2065 | * serial drivers can disable console output before suspending a port, and can | |
2066 | * re-enable output afterwards. | |
2067 | */ | |
2068 | void console_stop(struct console *console) | |
2069 | { | |
ac751efa | 2070 | console_lock(); |
1da177e4 | 2071 | console->flags &= ~CON_ENABLED; |
ac751efa | 2072 | console_unlock(); |
1da177e4 LT |
2073 | } |
2074 | EXPORT_SYMBOL(console_stop); | |
2075 | ||
2076 | void console_start(struct console *console) | |
2077 | { | |
ac751efa | 2078 | console_lock(); |
1da177e4 | 2079 | console->flags |= CON_ENABLED; |
ac751efa | 2080 | console_unlock(); |
1da177e4 LT |
2081 | } |
2082 | EXPORT_SYMBOL(console_start); | |
2083 | ||
7bf69395 FDN |
2084 | static int __read_mostly keep_bootcon; |
2085 | ||
2086 | static int __init keep_bootcon_setup(char *str) | |
2087 | { | |
2088 | keep_bootcon = 1; | |
2089 | printk(KERN_INFO "debug: skip boot console de-registration.\n"); | |
2090 | ||
2091 | return 0; | |
2092 | } | |
2093 | ||
2094 | early_param("keep_bootcon", keep_bootcon_setup); | |
2095 | ||
1da177e4 LT |
2096 | /* |
2097 | * The console driver calls this routine during kernel initialization | |
2098 | * to register the console printing procedure with printk() and to | |
2099 | * print any messages that were printed by the kernel before the | |
2100 | * console driver was initialized. | |
4d091611 RG |
2101 | * |
2102 | * This can happen pretty early during the boot process (because of | |
2103 | * early_printk) - sometimes before setup_arch() completes - be careful | |
2104 | * of what kernel features are used - they may not be initialised yet. | |
2105 | * | |
2106 | * There are two types of consoles - bootconsoles (early_printk) and | |
2107 | * "real" consoles (everything which is not a bootconsole) which are | |
2108 | * handled differently. | |
2109 | * - Any number of bootconsoles can be registered at any time. | |
2110 | * - As soon as a "real" console is registered, all bootconsoles | |
2111 | * will be unregistered automatically. | |
2112 | * - Once a "real" console is registered, any attempt to register a | |
2113 | * bootconsoles will be rejected | |
1da177e4 | 2114 | */ |
4d091611 | 2115 | void register_console(struct console *newcon) |
1da177e4 | 2116 | { |
40dc5651 | 2117 | int i; |
1da177e4 | 2118 | unsigned long flags; |
4d091611 | 2119 | struct console *bcon = NULL; |
1da177e4 | 2120 | |
4d091611 RG |
2121 | /* |
2122 | * before we register a new CON_BOOT console, make sure we don't | |
2123 | * already have a valid console | |
2124 | */ | |
2125 | if (console_drivers && newcon->flags & CON_BOOT) { | |
2126 | /* find the last or real console */ | |
2127 | for_each_console(bcon) { | |
2128 | if (!(bcon->flags & CON_BOOT)) { | |
2129 | printk(KERN_INFO "Too late to register bootconsole %s%d\n", | |
2130 | newcon->name, newcon->index); | |
2131 | return; | |
2132 | } | |
2133 | } | |
69331af7 GH |
2134 | } |
2135 | ||
4d091611 RG |
2136 | if (console_drivers && console_drivers->flags & CON_BOOT) |
2137 | bcon = console_drivers; | |
2138 | ||
2139 | if (preferred_console < 0 || bcon || !console_drivers) | |
1da177e4 LT |
2140 | preferred_console = selected_console; |
2141 | ||
4d091611 RG |
2142 | if (newcon->early_setup) |
2143 | newcon->early_setup(); | |
18a8bd94 | 2144 | |
1da177e4 LT |
2145 | /* |
2146 | * See if we want to use this console driver. If we | |
2147 | * didn't select a console we take the first one | |
2148 | * that registers here. | |
2149 | */ | |
2150 | if (preferred_console < 0) { | |
4d091611 RG |
2151 | if (newcon->index < 0) |
2152 | newcon->index = 0; | |
2153 | if (newcon->setup == NULL || | |
2154 | newcon->setup(newcon, NULL) == 0) { | |
2155 | newcon->flags |= CON_ENABLED; | |
2156 | if (newcon->device) { | |
2157 | newcon->flags |= CON_CONSDEV; | |
cd3a1b85 JK |
2158 | preferred_console = 0; |
2159 | } | |
1da177e4 LT |
2160 | } |
2161 | } | |
2162 | ||
2163 | /* | |
2164 | * See if this console matches one we selected on | |
2165 | * the command line. | |
2166 | */ | |
40dc5651 JJ |
2167 | for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; |
2168 | i++) { | |
4d091611 | 2169 | if (strcmp(console_cmdline[i].name, newcon->name) != 0) |
1da177e4 | 2170 | continue; |
4d091611 RG |
2171 | if (newcon->index >= 0 && |
2172 | newcon->index != console_cmdline[i].index) | |
1da177e4 | 2173 | continue; |
4d091611 RG |
2174 | if (newcon->index < 0) |
2175 | newcon->index = console_cmdline[i].index; | |
f7511d5f ST |
2176 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
2177 | if (console_cmdline[i].brl_options) { | |
4d091611 RG |
2178 | newcon->flags |= CON_BRL; |
2179 | braille_register_console(newcon, | |
f7511d5f ST |
2180 | console_cmdline[i].index, |
2181 | console_cmdline[i].options, | |
2182 | console_cmdline[i].brl_options); | |
2183 | return; | |
2184 | } | |
2185 | #endif | |
4d091611 RG |
2186 | if (newcon->setup && |
2187 | newcon->setup(newcon, console_cmdline[i].options) != 0) | |
1da177e4 | 2188 | break; |
4d091611 RG |
2189 | newcon->flags |= CON_ENABLED; |
2190 | newcon->index = console_cmdline[i].index; | |
ab4af03a | 2191 | if (i == selected_console) { |
4d091611 | 2192 | newcon->flags |= CON_CONSDEV; |
ab4af03a GE |
2193 | preferred_console = selected_console; |
2194 | } | |
1da177e4 LT |
2195 | break; |
2196 | } | |
2197 | ||
4d091611 | 2198 | if (!(newcon->flags & CON_ENABLED)) |
1da177e4 LT |
2199 | return; |
2200 | ||
8259cf43 RG |
2201 | /* |
2202 | * If we have a bootconsole, and are switching to a real console, | |
2203 | * don't print everything out again, since when the boot console, and | |
2204 | * the real console are the same physical device, it's annoying to | |
2205 | * see the beginning boot messages twice | |
2206 | */ | |
2207 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) | |
4d091611 | 2208 | newcon->flags &= ~CON_PRINTBUFFER; |
1da177e4 LT |
2209 | |
2210 | /* | |
2211 | * Put this console in the list - keep the | |
2212 | * preferred driver at the head of the list. | |
2213 | */ | |
ac751efa | 2214 | console_lock(); |
4d091611 RG |
2215 | if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
2216 | newcon->next = console_drivers; | |
2217 | console_drivers = newcon; | |
2218 | if (newcon->next) | |
2219 | newcon->next->flags &= ~CON_CONSDEV; | |
1da177e4 | 2220 | } else { |
4d091611 RG |
2221 | newcon->next = console_drivers->next; |
2222 | console_drivers->next = newcon; | |
1da177e4 | 2223 | } |
4d091611 | 2224 | if (newcon->flags & CON_PRINTBUFFER) { |
1da177e4 | 2225 | /* |
ac751efa | 2226 | * console_unlock(); will print out the buffered messages |
1da177e4 LT |
2227 | * for us. |
2228 | */ | |
07354eb1 | 2229 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2230 | console_seq = syslog_seq; |
2231 | console_idx = syslog_idx; | |
07354eb1 | 2232 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
fe3d8ad3 FT |
2233 | /* |
2234 | * We're about to replay the log buffer. Only do this to the | |
2235 | * just-registered console to avoid excessive message spam to | |
2236 | * the already-registered consoles. | |
2237 | */ | |
2238 | exclusive_console = newcon; | |
1da177e4 | 2239 | } |
ac751efa | 2240 | console_unlock(); |
fbc92a34 | 2241 | console_sysfs_notify(); |
8259cf43 RG |
2242 | |
2243 | /* | |
2244 | * By unregistering the bootconsoles after we enable the real console | |
2245 | * we get the "console xxx enabled" message on all the consoles - | |
2246 | * boot consoles, real consoles, etc - this is to ensure that end | |
2247 | * users know there might be something in the kernel's log buffer that | |
2248 | * went to the bootconsole (that they do not see on the real console) | |
2249 | */ | |
7bf69395 FDN |
2250 | if (bcon && |
2251 | ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && | |
2252 | !keep_bootcon) { | |
8259cf43 RG |
2253 | /* we need to iterate through twice, to make sure we print |
2254 | * everything out, before we unregister the console(s) | |
2255 | */ | |
2256 | printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n", | |
2257 | newcon->name, newcon->index); | |
2258 | for_each_console(bcon) | |
2259 | if (bcon->flags & CON_BOOT) | |
2260 | unregister_console(bcon); | |
2261 | } else { | |
2262 | printk(KERN_INFO "%sconsole [%s%d] enabled\n", | |
2263 | (newcon->flags & CON_BOOT) ? "boot" : "" , | |
2264 | newcon->name, newcon->index); | |
2265 | } | |
1da177e4 LT |
2266 | } |
2267 | EXPORT_SYMBOL(register_console); | |
2268 | ||
40dc5651 | 2269 | int unregister_console(struct console *console) |
1da177e4 | 2270 | { |
40dc5651 | 2271 | struct console *a, *b; |
1da177e4 LT |
2272 | int res = 1; |
2273 | ||
f7511d5f ST |
2274 | #ifdef CONFIG_A11Y_BRAILLE_CONSOLE |
2275 | if (console->flags & CON_BRL) | |
2276 | return braille_unregister_console(console); | |
2277 | #endif | |
2278 | ||
ac751efa | 2279 | console_lock(); |
1da177e4 LT |
2280 | if (console_drivers == console) { |
2281 | console_drivers=console->next; | |
2282 | res = 0; | |
e9b15b54 | 2283 | } else if (console_drivers) { |
1da177e4 LT |
2284 | for (a=console_drivers->next, b=console_drivers ; |
2285 | a; b=a, a=b->next) { | |
2286 | if (a == console) { | |
2287 | b->next = a->next; | |
2288 | res = 0; | |
2289 | break; | |
40dc5651 | 2290 | } |
1da177e4 LT |
2291 | } |
2292 | } | |
40dc5651 | 2293 | |
69331af7 | 2294 | /* |
ab4af03a GE |
2295 | * If this isn't the last console and it has CON_CONSDEV set, we |
2296 | * need to set it on the next preferred console. | |
1da177e4 | 2297 | */ |
69331af7 | 2298 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
ab4af03a | 2299 | console_drivers->flags |= CON_CONSDEV; |
1da177e4 | 2300 | |
ac751efa | 2301 | console_unlock(); |
fbc92a34 | 2302 | console_sysfs_notify(); |
1da177e4 LT |
2303 | return res; |
2304 | } | |
2305 | EXPORT_SYMBOL(unregister_console); | |
d59745ce | 2306 | |
034260d6 | 2307 | static int __init printk_late_init(void) |
0c5564bd | 2308 | { |
4d091611 RG |
2309 | struct console *con; |
2310 | ||
2311 | for_each_console(con) { | |
4c30c6f5 | 2312 | if (!keep_bootcon && con->flags & CON_BOOT) { |
cb00e99c | 2313 | printk(KERN_INFO "turn off boot console %s%d\n", |
4d091611 | 2314 | con->name, con->index); |
42c2c8c8 | 2315 | unregister_console(con); |
cb00e99c | 2316 | } |
0c5564bd | 2317 | } |
034260d6 | 2318 | hotcpu_notifier(console_cpu_notify, 0); |
0c5564bd RG |
2319 | return 0; |
2320 | } | |
034260d6 | 2321 | late_initcall(printk_late_init); |
0c5564bd | 2322 | |
7ef3d2fd | 2323 | #if defined CONFIG_PRINTK |
717115e1 | 2324 | |
600e1458 PZ |
2325 | int printk_sched(const char *fmt, ...) |
2326 | { | |
2327 | unsigned long flags; | |
2328 | va_list args; | |
2329 | char *buf; | |
2330 | int r; | |
2331 | ||
2332 | local_irq_save(flags); | |
2333 | buf = __get_cpu_var(printk_sched_buf); | |
2334 | ||
2335 | va_start(args, fmt); | |
2336 | r = vsnprintf(buf, PRINTK_BUF_SIZE, fmt, args); | |
2337 | va_end(args); | |
2338 | ||
2339 | __this_cpu_or(printk_pending, PRINTK_PENDING_SCHED); | |
2340 | local_irq_restore(flags); | |
2341 | ||
2342 | return r; | |
2343 | } | |
2344 | ||
1da177e4 LT |
2345 | /* |
2346 | * printk rate limiting, lifted from the networking subsystem. | |
2347 | * | |
641de9d8 UKK |
2348 | * This enforces a rate limit: not more than 10 kernel messages |
2349 | * every 5s to make a denial-of-service attack impossible. | |
1da177e4 | 2350 | */ |
641de9d8 UKK |
2351 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
2352 | ||
5c828713 | 2353 | int __printk_ratelimit(const char *func) |
1da177e4 | 2354 | { |
5c828713 | 2355 | return ___ratelimit(&printk_ratelimit_state, func); |
1da177e4 | 2356 | } |
5c828713 | 2357 | EXPORT_SYMBOL(__printk_ratelimit); |
f46c4833 AM |
2358 | |
2359 | /** | |
2360 | * printk_timed_ratelimit - caller-controlled printk ratelimiting | |
2361 | * @caller_jiffies: pointer to caller's state | |
2362 | * @interval_msecs: minimum interval between prints | |
2363 | * | |
2364 | * printk_timed_ratelimit() returns true if more than @interval_msecs | |
2365 | * milliseconds have elapsed since the last time printk_timed_ratelimit() | |
2366 | * returned true. | |
2367 | */ | |
2368 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, | |
2369 | unsigned int interval_msecs) | |
2370 | { | |
f2d28a2e GK |
2371 | if (*caller_jiffies == 0 |
2372 | || !time_in_range(jiffies, *caller_jiffies, | |
2373 | *caller_jiffies | |
2374 | + msecs_to_jiffies(interval_msecs))) { | |
2375 | *caller_jiffies = jiffies; | |
f46c4833 AM |
2376 | return true; |
2377 | } | |
2378 | return false; | |
2379 | } | |
2380 | EXPORT_SYMBOL(printk_timed_ratelimit); | |
456b565c SK |
2381 | |
2382 | static DEFINE_SPINLOCK(dump_list_lock); | |
2383 | static LIST_HEAD(dump_list); | |
2384 | ||
2385 | /** | |
2386 | * kmsg_dump_register - register a kernel log dumper. | |
6485536b | 2387 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2388 | * |
2389 | * Adds a kernel log dumper to the system. The dump callback in the | |
2390 | * structure will be called when the kernel oopses or panics and must be | |
2391 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. | |
2392 | */ | |
2393 | int kmsg_dump_register(struct kmsg_dumper *dumper) | |
2394 | { | |
2395 | unsigned long flags; | |
2396 | int err = -EBUSY; | |
2397 | ||
2398 | /* The dump callback needs to be set */ | |
2399 | if (!dumper->dump) | |
2400 | return -EINVAL; | |
2401 | ||
2402 | spin_lock_irqsave(&dump_list_lock, flags); | |
2403 | /* Don't allow registering multiple times */ | |
2404 | if (!dumper->registered) { | |
2405 | dumper->registered = 1; | |
fb842b00 | 2406 | list_add_tail_rcu(&dumper->list, &dump_list); |
456b565c SK |
2407 | err = 0; |
2408 | } | |
2409 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
2410 | ||
2411 | return err; | |
2412 | } | |
2413 | EXPORT_SYMBOL_GPL(kmsg_dump_register); | |
2414 | ||
2415 | /** | |
2416 | * kmsg_dump_unregister - unregister a kmsg dumper. | |
6485536b | 2417 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2418 | * |
2419 | * Removes a dump device from the system. Returns zero on success and | |
2420 | * %-EINVAL otherwise. | |
2421 | */ | |
2422 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) | |
2423 | { | |
2424 | unsigned long flags; | |
2425 | int err = -EINVAL; | |
2426 | ||
2427 | spin_lock_irqsave(&dump_list_lock, flags); | |
2428 | if (dumper->registered) { | |
2429 | dumper->registered = 0; | |
fb842b00 | 2430 | list_del_rcu(&dumper->list); |
456b565c SK |
2431 | err = 0; |
2432 | } | |
2433 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
fb842b00 | 2434 | synchronize_rcu(); |
456b565c SK |
2435 | |
2436 | return err; | |
2437 | } | |
2438 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); | |
2439 | ||
7ff9554b KS |
2440 | static bool always_kmsg_dump; |
2441 | module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); | |
2442 | ||
456b565c SK |
2443 | /** |
2444 | * kmsg_dump - dump kernel log to kernel message dumpers. | |
2445 | * @reason: the reason (oops, panic etc) for dumping | |
2446 | * | |
e2ae715d KS |
2447 | * Call each of the registered dumper's dump() callback, which can |
2448 | * retrieve the kmsg records with kmsg_dump_get_line() or | |
2449 | * kmsg_dump_get_buffer(). | |
456b565c SK |
2450 | */ |
2451 | void kmsg_dump(enum kmsg_dump_reason reason) | |
2452 | { | |
456b565c | 2453 | struct kmsg_dumper *dumper; |
456b565c SK |
2454 | unsigned long flags; |
2455 | ||
c22ab332 MG |
2456 | if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) |
2457 | return; | |
2458 | ||
e2ae715d KS |
2459 | rcu_read_lock(); |
2460 | list_for_each_entry_rcu(dumper, &dump_list, list) { | |
2461 | if (dumper->max_reason && reason > dumper->max_reason) | |
2462 | continue; | |
2463 | ||
2464 | /* initialize iterator with data about the stored records */ | |
2465 | dumper->active = true; | |
2466 | ||
2467 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2468 | dumper->cur_seq = clear_seq; | |
2469 | dumper->cur_idx = clear_idx; | |
2470 | dumper->next_seq = log_next_seq; | |
2471 | dumper->next_idx = log_next_idx; | |
2472 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2473 | ||
2474 | /* invoke dumper which will iterate over records */ | |
2475 | dumper->dump(dumper, reason); | |
2476 | ||
2477 | /* reset iterator */ | |
2478 | dumper->active = false; | |
2479 | } | |
2480 | rcu_read_unlock(); | |
2481 | } | |
2482 | ||
2483 | /** | |
2484 | * kmsg_dump_get_line - retrieve one kmsg log line | |
2485 | * @dumper: registered kmsg dumper | |
2486 | * @syslog: include the "<4>" prefixes | |
2487 | * @line: buffer to copy the line to | |
2488 | * @size: maximum size of the buffer | |
2489 | * @len: length of line placed into buffer | |
2490 | * | |
2491 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2492 | * record, and copy one record into the provided buffer. | |
2493 | * | |
2494 | * Consecutive calls will return the next available record moving | |
2495 | * towards the end of the buffer with the youngest messages. | |
2496 | * | |
2497 | * A return value of FALSE indicates that there are no more records to | |
2498 | * read. | |
2499 | */ | |
2500 | bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, | |
2501 | char *line, size_t size, size_t *len) | |
2502 | { | |
2503 | unsigned long flags; | |
2504 | struct log *msg; | |
2505 | size_t l = 0; | |
2506 | bool ret = false; | |
2507 | ||
2508 | if (!dumper->active) | |
2509 | goto out; | |
7ff9554b | 2510 | |
07354eb1 | 2511 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
e2ae715d KS |
2512 | if (dumper->cur_seq < log_first_seq) { |
2513 | /* messages are gone, move to first available one */ | |
2514 | dumper->cur_seq = log_first_seq; | |
2515 | dumper->cur_idx = log_first_idx; | |
2516 | } | |
456b565c | 2517 | |
e2ae715d KS |
2518 | /* last entry */ |
2519 | if (dumper->cur_seq >= log_next_seq) { | |
2520 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2521 | goto out; | |
2522 | } | |
456b565c | 2523 | |
e2ae715d KS |
2524 | msg = log_from_idx(dumper->cur_idx); |
2525 | l = msg_print_text(msg, syslog, | |
2526 | line, size); | |
2527 | ||
2528 | dumper->cur_idx = log_next(dumper->cur_idx); | |
2529 | dumper->cur_seq++; | |
2530 | ret = true; | |
2531 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2532 | out: | |
2533 | if (len) | |
2534 | *len = l; | |
2535 | return ret; | |
2536 | } | |
2537 | EXPORT_SYMBOL_GPL(kmsg_dump_get_line); | |
2538 | ||
2539 | /** | |
2540 | * kmsg_dump_get_buffer - copy kmsg log lines | |
2541 | * @dumper: registered kmsg dumper | |
2542 | * @syslog: include the "<4>" prefixes | |
4f0f4af5 | 2543 | * @buf: buffer to copy the line to |
e2ae715d KS |
2544 | * @size: maximum size of the buffer |
2545 | * @len: length of line placed into buffer | |
2546 | * | |
2547 | * Start at the end of the kmsg buffer and fill the provided buffer | |
2548 | * with as many of the the *youngest* kmsg records that fit into it. | |
2549 | * If the buffer is large enough, all available kmsg records will be | |
2550 | * copied with a single call. | |
2551 | * | |
2552 | * Consecutive calls will fill the buffer with the next block of | |
2553 | * available older records, not including the earlier retrieved ones. | |
2554 | * | |
2555 | * A return value of FALSE indicates that there are no more records to | |
2556 | * read. | |
2557 | */ | |
2558 | bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, | |
2559 | char *buf, size_t size, size_t *len) | |
2560 | { | |
2561 | unsigned long flags; | |
2562 | u64 seq; | |
2563 | u32 idx; | |
2564 | u64 next_seq; | |
2565 | u32 next_idx; | |
2566 | size_t l = 0; | |
2567 | bool ret = false; | |
2568 | ||
2569 | if (!dumper->active) | |
2570 | goto out; | |
2571 | ||
2572 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2573 | if (dumper->cur_seq < log_first_seq) { | |
2574 | /* messages are gone, move to first available one */ | |
2575 | dumper->cur_seq = log_first_seq; | |
2576 | dumper->cur_idx = log_first_idx; | |
2577 | } | |
2578 | ||
2579 | /* last entry */ | |
2580 | if (dumper->cur_seq >= dumper->next_seq) { | |
2581 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2582 | goto out; | |
2583 | } | |
2584 | ||
2585 | /* calculate length of entire buffer */ | |
2586 | seq = dumper->cur_seq; | |
2587 | idx = dumper->cur_idx; | |
2588 | while (seq < dumper->next_seq) { | |
2589 | struct log *msg = log_from_idx(idx); | |
2590 | ||
2591 | l += msg_print_text(msg, true, NULL, 0); | |
2592 | idx = log_next(idx); | |
2593 | seq++; | |
2594 | } | |
2595 | ||
2596 | /* move first record forward until length fits into the buffer */ | |
2597 | seq = dumper->cur_seq; | |
2598 | idx = dumper->cur_idx; | |
2599 | while (l > size && seq < dumper->next_seq) { | |
2600 | struct log *msg = log_from_idx(idx); | |
456b565c | 2601 | |
e2ae715d KS |
2602 | l -= msg_print_text(msg, true, NULL, 0); |
2603 | idx = log_next(idx); | |
2604 | seq++; | |
456b565c | 2605 | } |
e2ae715d KS |
2606 | |
2607 | /* last message in next interation */ | |
2608 | next_seq = seq; | |
2609 | next_idx = idx; | |
2610 | ||
2611 | l = 0; | |
2612 | while (seq < dumper->next_seq) { | |
2613 | struct log *msg = log_from_idx(idx); | |
2614 | ||
2615 | l += msg_print_text(msg, syslog, | |
2616 | buf + l, size - l); | |
2617 | ||
2618 | idx = log_next(idx); | |
2619 | seq++; | |
2620 | } | |
2621 | ||
2622 | dumper->next_seq = next_seq; | |
2623 | dumper->next_idx = next_idx; | |
2624 | ret = true; | |
7ff9554b | 2625 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
e2ae715d KS |
2626 | out: |
2627 | if (len) | |
2628 | *len = l; | |
2629 | return ret; | |
2630 | } | |
2631 | EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); | |
456b565c | 2632 | |
e2ae715d KS |
2633 | /** |
2634 | * kmsg_dump_rewind - reset the interator | |
2635 | * @dumper: registered kmsg dumper | |
2636 | * | |
2637 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
2638 | * kmsg_dump_get_buffer() can be called again and used multiple | |
2639 | * times within the same dumper.dump() callback. | |
2640 | */ | |
2641 | void kmsg_dump_rewind(struct kmsg_dumper *dumper) | |
2642 | { | |
2643 | unsigned long flags; | |
2644 | ||
2645 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2646 | dumper->cur_seq = clear_seq; | |
2647 | dumper->cur_idx = clear_idx; | |
2648 | dumper->next_seq = log_next_seq; | |
2649 | dumper->next_idx = log_next_idx; | |
2650 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
456b565c | 2651 | } |
e2ae715d | 2652 | EXPORT_SYMBOL_GPL(kmsg_dump_rewind); |
7ef3d2fd | 2653 | #endif |