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
];
33 int kdb_printf_cpu
= -1;
35 static int kgdb_transition_check(char *buffer
)
37 if (buffer
[0] != '+' && buffer
[0] != '$') {
38 KDB_STATE_SET(KGDB_TRANS
);
39 kdb_printf("%s", buffer
);
41 int slen
= strlen(buffer
);
42 if (slen
> 3 && buffer
[slen
- 3] == '#') {
43 kdb_gdb_state_pass(buffer
);
44 strcpy(buffer
, "kgdb");
45 KDB_STATE_SET(DOING_KGDB
);
52 static int kdb_read_get_key(char *buffer
, size_t bufsize
)
54 #define ESCAPE_UDELAY 1000
55 #define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
56 char escape_data
[5]; /* longest vt100 escape sequence is 4 bytes */
57 char *ped
= escape_data
;
59 get_char_func
*f
, *f_escape
= NULL
;
62 for (f
= &kdb_poll_funcs
[0]; ; ++f
) {
64 /* Reset NMI watchdog once per poll loop */
66 f
= &kdb_poll_funcs
[0];
68 if (escape_delay
== 2) {
73 if (escape_delay
== 1) {
82 udelay(ESCAPE_UDELAY
);
94 if (escape_delay
== 0 && key
== '\e') {
95 escape_delay
= ESCAPE_DELAY
;
105 if (ped
- escape_data
== 1) {
108 } else if (ped
- escape_data
== 2) {
113 } else if (ped
- escape_data
== 3) {
117 case 'A': /* \e[A, up arrow */
120 case 'B': /* \e[B, down arrow */
123 case 'C': /* \e[C, right arrow */
126 case 'D': /* \e[D, left arrow */
129 case '1': /* dropthrough */
130 case '3': /* dropthrough */
131 /* \e[<1,3,4>], may be home, del, end */
138 escape_data
[0] = mapkey
;
139 escape_data
[1] = '\0';
144 } else if (ped
- escape_data
== 4) {
145 /* \e[<1,3,4><something> */
148 switch (escape_data
[2]) {
149 case '1': /* \e[1~, home */
152 case '3': /* \e[3~, del */
155 case '4': /* \e[4~, end */
161 escape_data
[0] = mapkey
;
162 escape_data
[1] = '\0';
168 break; /* A key to process */
176 * This function reads a string of characters, terminated by
177 * a newline, or by reaching the end of the supplied buffer,
178 * from the current kernel debugger console device.
180 * buffer - Address of character buffer to receive input characters.
181 * bufsize - size, in bytes, of the character buffer
183 * Returns a pointer to the buffer containing the received
184 * character string. This string will be terminated by a
187 * No locks are required to be held upon entry to this
188 * function. It is not reentrant - it relies on the fact
189 * that while kdb is running on only one "master debug" cpu.
192 * The buffer size must be >= 2. A buffer size of 2 means that the caller only
193 * wants a single key.
195 * An escape key could be the start of a vt100 control sequence such as \e[D
196 * (left arrow) or it could be a character in its own right. The standard
197 * method for detecting the difference is to wait for 2 seconds to see if there
198 * are any other characters. kdb is complicated by the lack of a timer service
199 * (interrupts are off), by multiple input sources and by the need to sometimes
200 * return after just one key. Escape sequence processing has to be done as
201 * states in the polling loop.
204 static char *kdb_read(char *buffer
, size_t bufsize
)
207 char *bufend
= buffer
+bufsize
-2; /* Reserve space for newline
212 static char tmpbuffer
[CMD_BUFLEN
];
213 int len
= strlen(buffer
);
218 int diag
, dtab_count
;
222 diag
= kdbgetintenv("DTABCOUNT", &dtab_count
);
228 if (*(buffer
+len
-1) == '\n')
234 kdb_printf("%s", buffer
);
236 key
= kdb_read_get_key(buffer
, bufsize
);
242 case 8: /* backspace */
245 memcpy(tmpbuffer
, cp
, lastchar
- cp
);
246 memcpy(cp
-1, tmpbuffer
, lastchar
- cp
);
248 *(--lastchar
) = '\0';
250 kdb_printf("\b%s \r", cp
);
253 kdb_printf(kdb_prompt_str
);
254 kdb_printf("%s", buffer
);
261 if (!KDB_STATE(KGDB_TRANS
)) {
262 KDB_STATE_SET(KGDB_TRANS
);
263 kdb_printf("%s", buffer
);
269 memcpy(tmpbuffer
, cp
+1, lastchar
- cp
- 1);
270 memcpy(cp
, tmpbuffer
, lastchar
- cp
- 1);
271 *(--lastchar
) = '\0';
272 kdb_printf("%s \r", cp
);
275 kdb_printf(kdb_prompt_str
);
276 kdb_printf("%s", buffer
);
283 kdb_printf(kdb_prompt_str
);
289 kdb_printf("%s", cp
);
300 memset(tmpbuffer
, ' ',
301 strlen(kdb_prompt_str
) + (lastchar
-buffer
));
302 *(tmpbuffer
+strlen(kdb_prompt_str
) +
303 (lastchar
-buffer
)) = '\0';
304 kdb_printf("\r%s\r", tmpbuffer
);
305 *lastchar
= (char)key
;
306 *(lastchar
+1) = '\0';
310 kdb_printf("%c", *cp
);
315 memset(tmpbuffer
, ' ',
316 strlen(kdb_prompt_str
) + (lastchar
-buffer
));
317 *(tmpbuffer
+strlen(kdb_prompt_str
) +
318 (lastchar
-buffer
)) = '\0';
319 kdb_printf("\r%s\r", tmpbuffer
);
320 *lastchar
= (char)key
;
321 *(lastchar
+1) = '\0';
327 while (*p_tmp
== ' ')
331 memcpy(tmpbuffer
, p_tmp
, cp
-p_tmp
);
332 *(tmpbuffer
+ (cp
-p_tmp
)) = '\0';
333 p_tmp
= strrchr(tmpbuffer
, ' ');
339 count
= kallsyms_symbol_complete(p_tmp
,
341 (p_tmp
- tmpbuffer
));
342 if (tab
== 2 && count
> 0) {
343 kdb_printf("\n%d symbols are found.", count
);
344 if (count
> dtab_count
) {
346 kdb_printf(" But only first %d symbols will"
347 " be printed.\nYou can change the"
348 " environment variable DTABCOUNT.",
352 for (i
= 0; i
< count
; i
++) {
353 if (kallsyms_symbol_next(p_tmp
, i
) < 0)
355 kdb_printf("%s ", p_tmp
);
356 *(p_tmp
+ len
) = '\0';
361 kdb_printf(kdb_prompt_str
);
362 kdb_printf("%s", buffer
);
363 } else if (tab
!= 2 && count
> 0) {
364 len_tmp
= strlen(p_tmp
);
365 strncpy(p_tmp
+len_tmp
, cp
, lastchar
-cp
+1);
366 len_tmp
= strlen(p_tmp
);
367 strncpy(cp
, p_tmp
+len
, len_tmp
-len
+ 1);
369 kdb_printf("%s", cp
);
373 kdb_nextline
= 1; /* reset output line number */
376 if (key
>= 32 && lastchar
< bufend
) {
378 memcpy(tmpbuffer
, cp
, lastchar
- cp
);
379 memcpy(cp
+1, tmpbuffer
, lastchar
- cp
);
382 kdb_printf("%s\r", cp
);
386 kdb_printf(kdb_prompt_str
);
387 kdb_printf("%s", buffer
);
392 /* The kgdb transition check will hide
393 * printed characters if we think that
394 * kgdb is connecting, until the check
396 if (!KDB_STATE(KGDB_TRANS
)) {
397 if (kgdb_transition_check(buffer
))
400 kdb_printf("%c", key
);
403 /* Special escape to kgdb */
404 if (lastchar
- buffer
>= 5 &&
405 strcmp(lastchar
- 5, "$?#3f") == 0) {
406 kdb_gdb_state_pass(lastchar
- 5);
407 strcpy(buffer
, "kgdb");
408 KDB_STATE_SET(DOING_KGDB
);
411 if (lastchar
- buffer
>= 11 &&
412 strcmp(lastchar
- 11, "$qSupported") == 0) {
413 kdb_gdb_state_pass(lastchar
- 11);
414 strcpy(buffer
, "kgdb");
415 KDB_STATE_SET(DOING_KGDB
);
427 * Print the prompt string and read a command from the
431 * buffer Address of buffer to receive command
432 * bufsize Size of buffer in bytes
433 * prompt Pointer to string to use as prompt string
435 * Pointer to command buffer.
439 * For SMP kernels, the processor number will be
440 * substituted for %d, %x or %o in the prompt.
443 char *kdb_getstr(char *buffer
, size_t bufsize
, const char *prompt
)
445 if (prompt
&& kdb_prompt_str
!= prompt
)
446 strncpy(kdb_prompt_str
, prompt
, CMD_BUFLEN
);
447 kdb_printf(kdb_prompt_str
);
448 kdb_nextline
= 1; /* Prompt and input resets line number */
449 return kdb_read(buffer
, bufsize
);
455 * Get rid of any buffered console input.
464 * Call this function whenever you want to flush input. If there is any
465 * outstanding input, it ignores all characters until there has been no
466 * data for approximately 1ms.
469 static void kdb_input_flush(void)
474 while (flush_delay
) {
477 touch_nmi_watchdog();
478 for (f
= &kdb_poll_funcs
[0]; *f
; ++f
) {
493 * Print a string to the output device(s).
496 * printf-like format and optional args.
502 * use 'kdbcons->write()' to avoid polluting 'log_buf' with
505 * If the user is doing a cmd args | grep srch
506 * then kdb_grepping_flag is set.
507 * In that case we need to accumulate full lines (ending in \n) before
508 * searching for the pattern.
511 static char kdb_buffer
[256]; /* A bit too big to go on stack */
512 static char *next_avail
= kdb_buffer
;
513 static int size_avail
;
514 static int suspend_grep
;
517 * search arg1 to see if it contains arg2
518 * (kdmain.c provides flags for ^pat and pat$)
520 * return 1 for found, 0 for not found
522 static int kdb_search_string(char *searched
, char *searchfor
)
527 /* not counting the newline at the end of "searched" */
528 len1
= strlen(searched
)-1;
529 len2
= strlen(searchfor
);
532 if (kdb_grep_leading
&& kdb_grep_trailing
&& len1
!= len2
)
534 if (kdb_grep_leading
) {
535 if (!strncmp(searched
, searchfor
, len2
))
537 } else if (kdb_grep_trailing
) {
538 if (!strncmp(searched
+len1
-len2
, searchfor
, len2
))
541 firstchar
= *searchfor
;
543 while ((cp
= strchr(cp
, firstchar
))) {
544 if (!strncmp(cp
, searchfor
, len2
))
552 int vkdb_printf(enum kdb_msgsrc src
, const char *fmt
, va_list ap
)
557 int logging
, saved_loglevel
= 0;
560 int this_cpu
, old_cpu
;
561 char *cp
, *cp2
, *cphold
= NULL
, replaced_byte
= ' ';
562 char *moreprompt
= "more> ";
563 struct console
*c
= console_drivers
;
564 unsigned long uninitialized_var(flags
);
566 /* Serialize kdb_printf if multiple cpus try to write at once.
567 * But if any cpu goes recursive in kdb, just print the output,
568 * even if it is interleaved with any other text.
570 local_irq_save(flags
);
571 this_cpu
= smp_processor_id();
573 old_cpu
= cmpxchg(&kdb_printf_cpu
, -1, this_cpu
);
574 if (old_cpu
== -1 || old_cpu
== this_cpu
)
580 diag
= kdbgetintenv("LINES", &linecount
);
581 if (diag
|| linecount
<= 1)
584 diag
= kdbgetintenv("COLUMNS", &colcount
);
585 if (diag
|| colcount
<= 1)
588 diag
= kdbgetintenv("LOGGING", &logging
);
592 if (!kdb_grepping_flag
|| suspend_grep
) {
593 /* normally, every vsnprintf starts a new buffer */
594 next_avail
= kdb_buffer
;
595 size_avail
= sizeof(kdb_buffer
);
597 vsnprintf(next_avail
, size_avail
, fmt
, ap
);
600 * If kdb_parse() found that the command was cmd xxx | grep yyy
601 * then kdb_grepping_flag is set, and kdb_grep_string contains yyy
603 * Accumulate the print data up to a newline before searching it.
604 * (vsnprintf does null-terminate the string that it generates)
607 /* skip the search if prints are temporarily unconditional */
608 if (!suspend_grep
&& kdb_grepping_flag
) {
609 cp
= strchr(kdb_buffer
, '\n');
612 * Special cases that don't end with newlines
613 * but should be written without one:
614 * The "[nn]kdb> " prompt should
615 * appear at the front of the buffer.
617 * The "[nn]more " prompt should also be
618 * (MOREPROMPT -> moreprompt)
619 * written * but we print that ourselves,
620 * we set the suspend_grep flag to make
624 if (next_avail
== kdb_buffer
) {
626 * these should occur after a newline,
627 * so they will be at the front of the
631 len
= strlen(kdb_prompt_str
);
632 if (!strncmp(cp2
, kdb_prompt_str
, len
)) {
634 * We're about to start a new
635 * command, so we can go back
638 kdb_grepping_flag
= 0;
642 /* no newline; don't search/write the buffer
643 until one is there */
644 len
= strlen(kdb_buffer
);
645 next_avail
= kdb_buffer
+ len
;
646 size_avail
= sizeof(kdb_buffer
) - len
;
651 * The newline is present; print through it or discard
652 * it, depending on the results of the search.
654 cp
++; /* to byte after the newline */
655 replaced_byte
= *cp
; /* remember what/where it was */
657 *cp
= '\0'; /* end the string for our search */
660 * We now have a newline at the end of the string
661 * Only continue with this output if it contains the
664 fnd
= kdb_search_string(kdb_buffer
, kdb_grep_string
);
667 * At this point the complete line at the start
668 * of kdb_buffer can be discarded, as it does
669 * not contain what the user is looking for.
670 * Shift the buffer left.
672 *cphold
= replaced_byte
;
673 strcpy(kdb_buffer
, cphold
);
674 len
= strlen(kdb_buffer
);
675 next_avail
= kdb_buffer
+ len
;
676 size_avail
= sizeof(kdb_buffer
) - len
;
679 if (kdb_grepping_flag
>= KDB_GREPPING_FLAG_SEARCH
)
681 * This was a interactive search (using '/' at more
682 * prompt) and it has completed. Clear the flag.
684 kdb_grepping_flag
= 0;
686 * at this point the string is a full line and
687 * should be printed, up to the null.
693 * Write to all consoles.
695 retlen
= strlen(kdb_buffer
);
696 cp
= (char *) printk_skip_headers(kdb_buffer
);
697 if (!dbg_kdb_mode
&& kgdb_connected
) {
698 gdbstub_msg_write(cp
, retlen
- (cp
- kdb_buffer
));
700 if (dbg_io_ops
&& !dbg_io_ops
->is_console
) {
701 len
= retlen
- (cp
- kdb_buffer
);
704 dbg_io_ops
->write_char(*cp2
);
709 c
->write(c
, cp
, retlen
- (cp
- kdb_buffer
));
710 touch_nmi_watchdog();
715 saved_loglevel
= console_loglevel
;
716 console_loglevel
= CONSOLE_LOGLEVEL_SILENT
;
717 if (printk_get_level(kdb_buffer
) || src
== KDB_MSGSRC_PRINTK
)
718 printk("%s", kdb_buffer
);
720 pr_info("%s", kdb_buffer
);
723 if (KDB_STATE(PAGER
)) {
725 * Check printed string to decide how to bump the
726 * kdb_nextline to control when the more prompt should
732 if (kdb_buffer
[len
] == '\n') {
735 } else if (kdb_buffer
[len
] == '\r') {
741 kdb_nextline
+= got
/ (colcount
+ 1);
744 /* check for having reached the LINES number of printed lines */
745 if (kdb_nextline
>= linecount
) {
748 /* Watch out for recursion here. Any routine that calls
749 * kdb_printf will come back through here. And kdb_read
750 * uses kdb_printf to echo on serial consoles ...
752 kdb_nextline
= 1; /* In case of recursion */
757 moreprompt
= kdbgetenv("MOREPROMPT");
758 if (moreprompt
== NULL
)
759 moreprompt
= "more> ";
764 if (dbg_io_ops
&& !dbg_io_ops
->is_console
) {
765 len
= strlen(moreprompt
);
768 dbg_io_ops
->write_char(*cp
);
773 c
->write(c
, moreprompt
, strlen(moreprompt
));
774 touch_nmi_watchdog();
779 printk("%s", moreprompt
);
781 kdb_read(buf1
, 2); /* '2' indicates to return
782 * immediately after getting one key. */
783 kdb_nextline
= 1; /* Really set output line 1 */
785 /* empty and reset the buffer: */
786 kdb_buffer
[0] = '\0';
787 next_avail
= kdb_buffer
;
788 size_avail
= sizeof(kdb_buffer
);
789 if ((buf1
[0] == 'q') || (buf1
[0] == 'Q')) {
790 /* user hit q or Q */
791 KDB_FLAG_SET(CMD_INTERRUPT
); /* command interrupted */
792 KDB_STATE_CLEAR(PAGER
);
793 /* end of command output; back to normal mode */
794 kdb_grepping_flag
= 0;
796 } else if (buf1
[0] == ' ') {
798 suspend_grep
= 1; /* for this recursion */
799 } else if (buf1
[0] == '\n') {
800 kdb_nextline
= linecount
- 1;
802 suspend_grep
= 1; /* for this recursion */
803 } else if (buf1
[0] == '/' && !kdb_grepping_flag
) {
805 kdb_getstr(kdb_grep_string
, KDB_GREP_STRLEN
,
806 kdbgetenv("SEARCHPROMPT") ?: "search> ");
807 *strchrnul(kdb_grep_string
, '\n') = '\0';
808 kdb_grepping_flag
+= KDB_GREPPING_FLAG_SEARCH
;
809 suspend_grep
= 1; /* for this recursion */
810 } else if (buf1
[0] && buf1
[0] != '\n') {
811 /* user hit something other than enter */
812 suspend_grep
= 1; /* for this recursion */
815 "\nOnly 'q', 'Q' or '/' are processed at "
816 "more prompt, input ignored\n");
818 kdb_printf("\n'/' cannot be used during | "
819 "grep filtering, input ignored\n");
820 } else if (kdb_grepping_flag
) {
822 suspend_grep
= 1; /* for this recursion */
829 * For grep searches, shift the printed string left.
830 * replaced_byte contains the character that was overwritten with
831 * the terminating null, and cphold points to the null.
832 * Then adjust the notion of available space in the buffer.
834 if (kdb_grepping_flag
&& !suspend_grep
) {
835 *cphold
= replaced_byte
;
836 strcpy(kdb_buffer
, cphold
);
837 len
= strlen(kdb_buffer
);
838 next_avail
= kdb_buffer
+ len
;
839 size_avail
= sizeof(kdb_buffer
) - len
;
843 suspend_grep
= 0; /* end of what may have been a recursive call */
845 console_loglevel
= saved_loglevel
;
846 /* kdb_printf_cpu locked the code above. */
847 smp_store_release(&kdb_printf_cpu
, old_cpu
);
848 local_irq_restore(flags
);
852 int kdb_printf(const char *fmt
, ...)
858 r
= vkdb_printf(KDB_MSGSRC_INTERNAL
, fmt
, ap
);
863 EXPORT_SYMBOL_GPL(kdb_printf
);