2 * Kernel Debugger Architecture Independent Console I/O handler
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
8 * Copyright (c) 1999-2006 Silicon Graphics, Inc. All Rights Reserved.
9 * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
12 #include <linux/module.h>
13 #include <linux/types.h>
14 #include <linux/ctype.h>
15 #include <linux/kernel.h>
16 #include <linux/init.h>
17 #include <linux/kdev_t.h>
18 #include <linux/console.h>
19 #include <linux/string.h>
20 #include <linux/sched.h>
21 #include <linux/smp.h>
22 #include <linux/nmi.h>
23 #include <linux/delay.h>
24 #include <linux/kgdb.h>
25 #include <linux/kdb.h>
26 #include <linux/kallsyms.h>
27 #include "kdb_private.h"
29 #define CMD_BUFLEN 256
30 char kdb_prompt_str[CMD_BUFLEN];
34 static int kgdb_transition_check(char *buffer)
36 if (buffer[0] != '+' && buffer[0] != '$') {
37 KDB_STATE_SET(KGDB_TRANS);
38 kdb_printf("%s", buffer);
40 int slen = strlen(buffer);
41 if (slen > 3 && buffer[slen - 3] == '#') {
42 kdb_gdb_state_pass(buffer);
43 strcpy(buffer, "kgdb");
44 KDB_STATE_SET(DOING_KGDB);
51 static int kdb_read_get_key(char *buffer, size_t bufsize)
53 #define ESCAPE_UDELAY 1000
54 #define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
55 char escape_data[5]; /* longest vt100 escape sequence is 4 bytes */
56 char *ped = escape_data;
58 get_char_func *f, *f_escape = NULL;
61 for (f = &kdb_poll_funcs[0]; ; ++f) {
63 /* Reset NMI watchdog once per poll loop */
65 f = &kdb_poll_funcs[0];
67 if (escape_delay == 2) {
72 if (escape_delay == 1) {
81 udelay(ESCAPE_UDELAY);
93 if (escape_delay == 0 && key == '\e') {
94 escape_delay = ESCAPE_DELAY;
104 if (ped - escape_data == 1) {
107 } else if (ped - escape_data == 2) {
112 } else if (ped - escape_data == 3) {
116 case 'A': /* \e[A, up arrow */
119 case 'B': /* \e[B, down arrow */
122 case 'C': /* \e[C, right arrow */
125 case 'D': /* \e[D, left arrow */
128 case '1': /* dropthrough */
129 case '3': /* dropthrough */
130 /* \e[<1,3,4>], may be home, del, end */
137 escape_data[0] = mapkey;
138 escape_data[1] = '\0';
143 } else if (ped - escape_data == 4) {
144 /* \e[<1,3,4><something> */
147 switch (escape_data[2]) {
148 case '1': /* \e[1~, home */
151 case '3': /* \e[3~, del */
154 case '4': /* \e[4~, end */
160 escape_data[0] = mapkey;
161 escape_data[1] = '\0';
167 break; /* A key to process */
175 * This function reads a string of characters, terminated by
176 * a newline, or by reaching the end of the supplied buffer,
177 * from the current kernel debugger console device.
179 * buffer - Address of character buffer to receive input characters.
180 * bufsize - size, in bytes, of the character buffer
182 * Returns a pointer to the buffer containing the received
183 * character string. This string will be terminated by a
186 * No locks are required to be held upon entry to this
187 * function. It is not reentrant - it relies on the fact
188 * that while kdb is running on only one "master debug" cpu.
191 * The buffer size must be >= 2. A buffer size of 2 means that the caller only
192 * wants a single key.
194 * An escape key could be the start of a vt100 control sequence such as \e[D
195 * (left arrow) or it could be a character in its own right. The standard
196 * method for detecting the difference is to wait for 2 seconds to see if there
197 * are any other characters. kdb is complicated by the lack of a timer service
198 * (interrupts are off), by multiple input sources and by the need to sometimes
199 * return after just one key. Escape sequence processing has to be done as
200 * states in the polling loop.
203 static char *kdb_read(char *buffer, size_t bufsize)
206 char *bufend = buffer+bufsize-2; /* Reserve space for newline
211 static char tmpbuffer[CMD_BUFLEN];
212 int len = strlen(buffer);
217 int diag, dtab_count;
219 static int last_crlf;
221 diag = kdbgetintenv("DTABCOUNT", &dtab_count);
227 if (*(buffer+len-1) == '\n')
233 kdb_printf("%s", buffer);
235 key = kdb_read_get_key(buffer, bufsize);
240 if (key != 10 && key != 13)
244 case 8: /* backspace */
247 memcpy(tmpbuffer, cp, lastchar - cp);
248 memcpy(cp-1, tmpbuffer, lastchar - cp);
250 *(--lastchar) = '\0';
252 kdb_printf("\b%s \r", cp);
255 kdb_printf(kdb_prompt_str);
256 kdb_printf("%s", buffer);
260 case 10: /* new line */
261 case 13: /* carriage return */
262 /* handle \n after \r */
263 if (last_crlf && last_crlf != key)
268 if (!KDB_STATE(KGDB_TRANS)) {
269 KDB_STATE_SET(KGDB_TRANS);
270 kdb_printf("%s", buffer);
276 memcpy(tmpbuffer, cp+1, lastchar - cp - 1);
277 memcpy(cp, tmpbuffer, lastchar - cp - 1);
278 *(--lastchar) = '\0';
279 kdb_printf("%s \r", cp);
282 kdb_printf(kdb_prompt_str);
283 kdb_printf("%s", buffer);
290 kdb_printf(kdb_prompt_str);
296 kdb_printf("%s", cp);
307 memset(tmpbuffer, ' ',
308 strlen(kdb_prompt_str) + (lastchar-buffer));
309 *(tmpbuffer+strlen(kdb_prompt_str) +
310 (lastchar-buffer)) = '\0';
311 kdb_printf("\r%s\r", tmpbuffer);
312 *lastchar = (char)key;
313 *(lastchar+1) = '\0';
317 kdb_printf("%c", *cp);
322 memset(tmpbuffer, ' ',
323 strlen(kdb_prompt_str) + (lastchar-buffer));
324 *(tmpbuffer+strlen(kdb_prompt_str) +
325 (lastchar-buffer)) = '\0';
326 kdb_printf("\r%s\r", tmpbuffer);
327 *lastchar = (char)key;
328 *(lastchar+1) = '\0';
334 while (*p_tmp == ' ')
338 memcpy(tmpbuffer, p_tmp, cp-p_tmp);
339 *(tmpbuffer + (cp-p_tmp)) = '\0';
340 p_tmp = strrchr(tmpbuffer, ' ');
346 count = kallsyms_symbol_complete(p_tmp,
348 (p_tmp - tmpbuffer));
349 if (tab == 2 && count > 0) {
350 kdb_printf("\n%d symbols are found.", count);
351 if (count > dtab_count) {
353 kdb_printf(" But only first %d symbols will"
354 " be printed.\nYou can change the"
355 " environment variable DTABCOUNT.",
359 for (i = 0; i < count; i++) {
360 if (kallsyms_symbol_next(p_tmp, i) < 0)
362 kdb_printf("%s ", p_tmp);
363 *(p_tmp + len) = '\0';
368 kdb_printf(kdb_prompt_str);
369 kdb_printf("%s", buffer);
370 } else if (tab != 2 && count > 0) {
371 len_tmp = strlen(p_tmp);
372 strncpy(p_tmp+len_tmp, cp, lastchar-cp+1);
373 len_tmp = strlen(p_tmp);
374 strncpy(cp, p_tmp+len, len_tmp-len + 1);
376 kdb_printf("%s", cp);
380 kdb_nextline = 1; /* reset output line number */
383 if (key >= 32 && lastchar < bufend) {
385 memcpy(tmpbuffer, cp, lastchar - cp);
386 memcpy(cp+1, tmpbuffer, lastchar - cp);
389 kdb_printf("%s\r", cp);
393 kdb_printf(kdb_prompt_str);
394 kdb_printf("%s", buffer);
399 /* The kgdb transition check will hide
400 * printed characters if we think that
401 * kgdb is connecting, until the check
403 if (!KDB_STATE(KGDB_TRANS)) {
404 if (kgdb_transition_check(buffer))
407 kdb_printf("%c", key);
410 /* Special escape to kgdb */
411 if (lastchar - buffer >= 5 &&
412 strcmp(lastchar - 5, "$?#3f") == 0) {
413 kdb_gdb_state_pass(lastchar - 5);
414 strcpy(buffer, "kgdb");
415 KDB_STATE_SET(DOING_KGDB);
418 if (lastchar - buffer >= 11 &&
419 strcmp(lastchar - 11, "$qSupported") == 0) {
420 kdb_gdb_state_pass(lastchar - 11);
421 strcpy(buffer, "kgdb");
422 KDB_STATE_SET(DOING_KGDB);
434 * Print the prompt string and read a command from the
438 * buffer Address of buffer to receive command
439 * bufsize Size of buffer in bytes
440 * prompt Pointer to string to use as prompt string
442 * Pointer to command buffer.
446 * For SMP kernels, the processor number will be
447 * substituted for %d, %x or %o in the prompt.
450 char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
452 if (prompt && kdb_prompt_str != prompt)
453 strncpy(kdb_prompt_str, prompt, CMD_BUFLEN);
454 kdb_printf(kdb_prompt_str);
455 kdb_nextline = 1; /* Prompt and input resets line number */
456 return kdb_read(buffer, bufsize);
462 * Get rid of any buffered console input.
471 * Call this function whenever you want to flush input. If there is any
472 * outstanding input, it ignores all characters until there has been no
473 * data for approximately 1ms.
476 static void kdb_input_flush(void)
481 while (flush_delay) {
484 touch_nmi_watchdog();
485 for (f = &kdb_poll_funcs[0]; *f; ++f) {
500 * Print a string to the output device(s).
503 * printf-like format and optional args.
509 * use 'kdbcons->write()' to avoid polluting 'log_buf' with
512 * If the user is doing a cmd args | grep srch
513 * then kdb_grepping_flag is set.
514 * In that case we need to accumulate full lines (ending in \n) before
515 * searching for the pattern.
518 static char kdb_buffer[256]; /* A bit too big to go on stack */
519 static char *next_avail = kdb_buffer;
520 static int size_avail;
521 static int suspend_grep;
524 * search arg1 to see if it contains arg2
525 * (kdmain.c provides flags for ^pat and pat$)
527 * return 1 for found, 0 for not found
529 static int kdb_search_string(char *searched, char *searchfor)
534 /* not counting the newline at the end of "searched" */
535 len1 = strlen(searched)-1;
536 len2 = strlen(searchfor);
539 if (kdb_grep_leading && kdb_grep_trailing && len1 != len2)
541 if (kdb_grep_leading) {
542 if (!strncmp(searched, searchfor, len2))
544 } else if (kdb_grep_trailing) {
545 if (!strncmp(searched+len1-len2, searchfor, len2))
548 firstchar = *searchfor;
550 while ((cp = strchr(cp, firstchar))) {
551 if (!strncmp(cp, searchfor, len2))
559 int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
564 int logging, saved_loglevel = 0;
565 int saved_trap_printk;
566 int got_printf_lock = 0;
569 char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
570 char *moreprompt = "more> ";
571 struct console *c = console_drivers;
572 static DEFINE_SPINLOCK(kdb_printf_lock);
573 unsigned long uninitialized_var(flags);
576 saved_trap_printk = kdb_trap_printk;
579 /* Serialize kdb_printf if multiple cpus try to write at once.
580 * But if any cpu goes recursive in kdb, just print the output,
581 * even if it is interleaved with any other text.
583 if (!KDB_STATE(PRINTF_LOCK)) {
584 KDB_STATE_SET(PRINTF_LOCK);
585 spin_lock_irqsave(&kdb_printf_lock, flags);
587 atomic_inc(&kdb_event);
589 __acquire(kdb_printf_lock);
592 diag = kdbgetintenv("LINES", &linecount);
593 if (diag || linecount <= 1)
596 diag = kdbgetintenv("COLUMNS", &colcount);
597 if (diag || colcount <= 1)
600 diag = kdbgetintenv("LOGGING", &logging);
604 if (!kdb_grepping_flag || suspend_grep) {
605 /* normally, every vsnprintf starts a new buffer */
606 next_avail = kdb_buffer;
607 size_avail = sizeof(kdb_buffer);
609 vsnprintf(next_avail, size_avail, fmt, ap);
612 * If kdb_parse() found that the command was cmd xxx | grep yyy
613 * then kdb_grepping_flag is set, and kdb_grep_string contains yyy
615 * Accumulate the print data up to a newline before searching it.
616 * (vsnprintf does null-terminate the string that it generates)
619 /* skip the search if prints are temporarily unconditional */
620 if (!suspend_grep && kdb_grepping_flag) {
621 cp = strchr(kdb_buffer, '\n');
624 * Special cases that don't end with newlines
625 * but should be written without one:
626 * The "[nn]kdb> " prompt should
627 * appear at the front of the buffer.
629 * The "[nn]more " prompt should also be
630 * (MOREPROMPT -> moreprompt)
631 * written * but we print that ourselves,
632 * we set the suspend_grep flag to make
636 if (next_avail == kdb_buffer) {
638 * these should occur after a newline,
639 * so they will be at the front of the
643 len = strlen(kdb_prompt_str);
644 if (!strncmp(cp2, kdb_prompt_str, len)) {
646 * We're about to start a new
647 * command, so we can go back
650 kdb_grepping_flag = 0;
654 /* no newline; don't search/write the buffer
655 until one is there */
656 len = strlen(kdb_buffer);
657 next_avail = kdb_buffer + len;
658 size_avail = sizeof(kdb_buffer) - len;
663 * The newline is present; print through it or discard
664 * it, depending on the results of the search.
666 cp++; /* to byte after the newline */
667 replaced_byte = *cp; /* remember what/where it was */
669 *cp = '\0'; /* end the string for our search */
672 * We now have a newline at the end of the string
673 * Only continue with this output if it contains the
676 fnd = kdb_search_string(kdb_buffer, kdb_grep_string);
679 * At this point the complete line at the start
680 * of kdb_buffer can be discarded, as it does
681 * not contain what the user is looking for.
682 * Shift the buffer left.
684 *cphold = replaced_byte;
685 strcpy(kdb_buffer, cphold);
686 len = strlen(kdb_buffer);
687 next_avail = kdb_buffer + len;
688 size_avail = sizeof(kdb_buffer) - len;
691 if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH)
693 * This was a interactive search (using '/' at more
694 * prompt) and it has completed. Clear the flag.
696 kdb_grepping_flag = 0;
698 * at this point the string is a full line and
699 * should be printed, up to the null.
705 * Write to all consoles.
707 retlen = strlen(kdb_buffer);
708 cp = (char *) printk_skip_level(kdb_buffer);
709 if (!dbg_kdb_mode && kgdb_connected) {
710 gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
712 if (dbg_io_ops && !dbg_io_ops->is_console) {
713 len = retlen - (cp - kdb_buffer);
716 dbg_io_ops->write_char(*cp2);
721 c->write(c, cp, retlen - (cp - kdb_buffer));
722 touch_nmi_watchdog();
727 saved_loglevel = console_loglevel;
728 console_loglevel = CONSOLE_LOGLEVEL_SILENT;
729 if (printk_get_level(kdb_buffer) || src == KDB_MSGSRC_PRINTK)
730 printk("%s", kdb_buffer);
732 pr_info("%s", kdb_buffer);
735 if (KDB_STATE(PAGER)) {
737 * Check printed string to decide how to bump the
738 * kdb_nextline to control when the more prompt should
744 if (kdb_buffer[len] == '\n') {
747 } else if (kdb_buffer[len] == '\r') {
753 kdb_nextline += got / (colcount + 1);
756 /* check for having reached the LINES number of printed lines */
757 if (kdb_nextline >= linecount) {
760 /* Watch out for recursion here. Any routine that calls
761 * kdb_printf will come back through here. And kdb_read
762 * uses kdb_printf to echo on serial consoles ...
764 kdb_nextline = 1; /* In case of recursion */
769 moreprompt = kdbgetenv("MOREPROMPT");
770 if (moreprompt == NULL)
771 moreprompt = "more> ";
776 if (dbg_io_ops && !dbg_io_ops->is_console) {
777 len = strlen(moreprompt);
780 dbg_io_ops->write_char(*cp);
785 c->write(c, moreprompt, strlen(moreprompt));
786 touch_nmi_watchdog();
791 printk("%s", moreprompt);
793 kdb_read(buf1, 2); /* '2' indicates to return
794 * immediately after getting one key. */
795 kdb_nextline = 1; /* Really set output line 1 */
797 /* empty and reset the buffer: */
798 kdb_buffer[0] = '\0';
799 next_avail = kdb_buffer;
800 size_avail = sizeof(kdb_buffer);
801 if ((buf1[0] == 'q') || (buf1[0] == 'Q')) {
802 /* user hit q or Q */
803 KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */
804 KDB_STATE_CLEAR(PAGER);
805 /* end of command output; back to normal mode */
806 kdb_grepping_flag = 0;
808 } else if (buf1[0] == ' ') {
810 suspend_grep = 1; /* for this recursion */
811 } else if (buf1[0] == '\n') {
812 kdb_nextline = linecount - 1;
814 suspend_grep = 1; /* for this recursion */
815 } else if (buf1[0] == '/' && !kdb_grepping_flag) {
817 kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
818 kdbgetenv("SEARCHPROMPT") ?: "search> ");
819 *strchrnul(kdb_grep_string, '\n') = '\0';
820 kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
821 suspend_grep = 1; /* for this recursion */
822 } else if (buf1[0] && buf1[0] != '\n') {
823 /* user hit something other than enter */
824 suspend_grep = 1; /* for this recursion */
827 "\nOnly 'q', 'Q' or '/' are processed at "
828 "more prompt, input ignored\n");
830 kdb_printf("\n'/' cannot be used during | "
831 "grep filtering, input ignored\n");
832 } else if (kdb_grepping_flag) {
834 suspend_grep = 1; /* for this recursion */
841 * For grep searches, shift the printed string left.
842 * replaced_byte contains the character that was overwritten with
843 * the terminating null, and cphold points to the null.
844 * Then adjust the notion of available space in the buffer.
846 if (kdb_grepping_flag && !suspend_grep) {
847 *cphold = replaced_byte;
848 strcpy(kdb_buffer, cphold);
849 len = strlen(kdb_buffer);
850 next_avail = kdb_buffer + len;
851 size_avail = sizeof(kdb_buffer) - len;
855 suspend_grep = 0; /* end of what may have been a recursive call */
857 console_loglevel = saved_loglevel;
858 if (KDB_STATE(PRINTF_LOCK) && got_printf_lock) {
860 spin_unlock_irqrestore(&kdb_printf_lock, flags);
861 KDB_STATE_CLEAR(PRINTF_LOCK);
862 atomic_dec(&kdb_event);
864 __release(kdb_printf_lock);
866 kdb_trap_printk = saved_trap_printk;
871 int kdb_printf(const char *fmt, ...)
877 r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap);
882 EXPORT_SYMBOL_GPL(kdb_printf);