1 /*
2 * Kernel Debugger Architecture Independent Console I/O handler
3 *
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
6 * for more details.
7 *
8 * Copyright (c) 1999-2006 Silicon Graphics, Inc. All Rights Reserved.
9 * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
10 */
11
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"
28
29 #define CMD_BUFLEN 256
30 char kdb_prompt_str[CMD_BUFLEN];
31
32 int kdb_trap_printk;
33 int kdb_printf_cpu = -1;
34
kgdb_transition_check(char * buffer)35 static int kgdb_transition_check(char *buffer)
36 {
37 if (buffer[0] != '+' && buffer[0] != '$') {
38 KDB_STATE_SET(KGDB_TRANS);
39 kdb_printf("%s", buffer);
40 } else {
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);
46 return 1;
47 }
48 }
49 return 0;
50 }
51
52 /**
53 * kdb_handle_escape() - validity check on an accumulated escape sequence.
54 * @buf: Accumulated escape characters to be examined. Note that buf
55 * is not a string, it is an array of characters and need not be
56 * nil terminated.
57 * @sz: Number of accumulated escape characters.
58 *
59 * Return: -1 if the escape sequence is unwanted, 0 if it is incomplete,
60 * otherwise it returns a mapped key value to pass to the upper layers.
61 */
kdb_handle_escape(char * buf,size_t sz)62 static int kdb_handle_escape(char *buf, size_t sz)
63 {
64 char *lastkey = buf + sz - 1;
65
66 switch (sz) {
67 case 1:
68 if (*lastkey == '\e')
69 return 0;
70 break;
71
72 case 2: /* \e<something> */
73 if (*lastkey == '[')
74 return 0;
75 break;
76
77 case 3:
78 switch (*lastkey) {
79 case 'A': /* \e[A, up arrow */
80 return 16;
81 case 'B': /* \e[B, down arrow */
82 return 14;
83 case 'C': /* \e[C, right arrow */
84 return 6;
85 case 'D': /* \e[D, left arrow */
86 return 2;
87 case '1': /* \e[<1,3,4>], may be home, del, end */
88 case '3':
89 case '4':
90 return 0;
91 }
92 break;
93
94 case 4:
95 if (*lastkey == '~') {
96 switch (buf[2]) {
97 case '1': /* \e[1~, home */
98 return 1;
99 case '3': /* \e[3~, del */
100 return 4;
101 case '4': /* \e[4~, end */
102 return 5;
103 }
104 }
105 break;
106 }
107
108 return -1;
109 }
110
111 /**
112 * kdb_getchar() - Read a single character from a kdb console (or consoles).
113 *
114 * Other than polling the various consoles that are currently enabled,
115 * most of the work done in this function is dealing with escape sequences.
116 *
117 * An escape key could be the start of a vt100 control sequence such as \e[D
118 * (left arrow) or it could be a character in its own right. The standard
119 * method for detecting the difference is to wait for 2 seconds to see if there
120 * are any other characters. kdb is complicated by the lack of a timer service
121 * (interrupts are off), by multiple input sources. Escape sequence processing
122 * has to be done as states in the polling loop.
123 *
124 * Return: The key pressed or a control code derived from an escape sequence.
125 */
kdb_getchar(void)126 char kdb_getchar(void)
127 {
128 #define ESCAPE_UDELAY 1000
129 #define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
130 char buf[4]; /* longest vt100 escape sequence is 4 bytes */
131 char *pbuf = buf;
132 int escape_delay = 0;
133 get_char_func *f, *f_prev = NULL;
134 int key;
135
136 for (f = &kdb_poll_funcs[0]; ; ++f) {
137 if (*f == NULL) {
138 /* Reset NMI watchdog once per poll loop */
139 touch_nmi_watchdog();
140 f = &kdb_poll_funcs[0];
141 }
142
143 key = (*f)();
144 if (key == -1) {
145 if (escape_delay) {
146 udelay(ESCAPE_UDELAY);
147 if (--escape_delay == 0)
148 return '\e';
149 }
150 continue;
151 }
152
153 /*
154 * When the first character is received (or we get a change
155 * input source) we set ourselves up to handle an escape
156 * sequences (just in case).
157 */
158 if (f_prev != f) {
159 f_prev = f;
160 pbuf = buf;
161 escape_delay = ESCAPE_DELAY;
162 }
163
164 *pbuf++ = key;
165 key = kdb_handle_escape(buf, pbuf - buf);
166 if (key < 0) /* no escape sequence; return best character */
167 return buf[pbuf - buf == 2 ? 1 : 0];
168 if (key > 0)
169 return key;
170 }
171
172 unreachable();
173 }
174
175 /*
176 * kdb_read
177 *
178 * This function reads a string of characters, terminated by
179 * a newline, or by reaching the end of the supplied buffer,
180 * from the current kernel debugger console device.
181 * Parameters:
182 * buffer - Address of character buffer to receive input characters.
183 * bufsize - size, in bytes, of the character buffer
184 * Returns:
185 * Returns a pointer to the buffer containing the received
186 * character string. This string will be terminated by a
187 * newline character.
188 * Locking:
189 * No locks are required to be held upon entry to this
190 * function. It is not reentrant - it relies on the fact
191 * that while kdb is running on only one "master debug" cpu.
192 * Remarks:
193 * The buffer size must be >= 2.
194 */
195
kdb_read(char * buffer,size_t bufsize)196 static char *kdb_read(char *buffer, size_t bufsize)
197 {
198 char *cp = buffer;
199 char *bufend = buffer+bufsize-2; /* Reserve space for newline
200 * and null byte */
201 char *lastchar;
202 char *p_tmp;
203 char tmp;
204 static char tmpbuffer[CMD_BUFLEN];
205 int len = strlen(buffer);
206 int len_tmp;
207 int tab = 0;
208 int count;
209 int i;
210 int diag, dtab_count;
211 int key, buf_size, ret;
212
213
214 diag = kdbgetintenv("DTABCOUNT", &dtab_count);
215 if (diag)
216 dtab_count = 30;
217
218 if (len > 0) {
219 cp += len;
220 if (*(buffer+len-1) == '\n')
221 cp--;
222 }
223
224 lastchar = cp;
225 *cp = '\0';
226 kdb_printf("%s", buffer);
227 poll_again:
228 key = kdb_getchar();
229 if (key != 9)
230 tab = 0;
231 switch (key) {
232 case 8: /* backspace */
233 if (cp > buffer) {
234 if (cp < lastchar) {
235 memcpy(tmpbuffer, cp, lastchar - cp);
236 memcpy(cp-1, tmpbuffer, lastchar - cp);
237 }
238 *(--lastchar) = '\0';
239 --cp;
240 kdb_printf("\b%s \r", cp);
241 tmp = *cp;
242 *cp = '\0';
243 kdb_printf(kdb_prompt_str);
244 kdb_printf("%s", buffer);
245 *cp = tmp;
246 }
247 break;
248 case 13: /* enter */
249 *lastchar++ = '\n';
250 *lastchar++ = '\0';
251 if (!KDB_STATE(KGDB_TRANS)) {
252 KDB_STATE_SET(KGDB_TRANS);
253 kdb_printf("%s", buffer);
254 }
255 kdb_printf("\n");
256 return buffer;
257 case 4: /* Del */
258 if (cp < lastchar) {
259 memcpy(tmpbuffer, cp+1, lastchar - cp - 1);
260 memcpy(cp, tmpbuffer, lastchar - cp - 1);
261 *(--lastchar) = '\0';
262 kdb_printf("%s \r", cp);
263 tmp = *cp;
264 *cp = '\0';
265 kdb_printf(kdb_prompt_str);
266 kdb_printf("%s", buffer);
267 *cp = tmp;
268 }
269 break;
270 case 1: /* Home */
271 if (cp > buffer) {
272 kdb_printf("\r");
273 kdb_printf(kdb_prompt_str);
274 cp = buffer;
275 }
276 break;
277 case 5: /* End */
278 if (cp < lastchar) {
279 kdb_printf("%s", cp);
280 cp = lastchar;
281 }
282 break;
283 case 2: /* Left */
284 if (cp > buffer) {
285 kdb_printf("\b");
286 --cp;
287 }
288 break;
289 case 14: /* Down */
290 memset(tmpbuffer, ' ',
291 strlen(kdb_prompt_str) + (lastchar-buffer));
292 *(tmpbuffer+strlen(kdb_prompt_str) +
293 (lastchar-buffer)) = '\0';
294 kdb_printf("\r%s\r", tmpbuffer);
295 *lastchar = (char)key;
296 *(lastchar+1) = '\0';
297 return lastchar;
298 case 6: /* Right */
299 if (cp < lastchar) {
300 kdb_printf("%c", *cp);
301 ++cp;
302 }
303 break;
304 case 16: /* Up */
305 memset(tmpbuffer, ' ',
306 strlen(kdb_prompt_str) + (lastchar-buffer));
307 *(tmpbuffer+strlen(kdb_prompt_str) +
308 (lastchar-buffer)) = '\0';
309 kdb_printf("\r%s\r", tmpbuffer);
310 *lastchar = (char)key;
311 *(lastchar+1) = '\0';
312 return lastchar;
313 case 9: /* Tab */
314 if (tab < 2)
315 ++tab;
316 p_tmp = buffer;
317 while (*p_tmp == ' ')
318 p_tmp++;
319 if (p_tmp > cp)
320 break;
321 memcpy(tmpbuffer, p_tmp, cp-p_tmp);
322 *(tmpbuffer + (cp-p_tmp)) = '\0';
323 p_tmp = strrchr(tmpbuffer, ' ');
324 if (p_tmp)
325 ++p_tmp;
326 else
327 p_tmp = tmpbuffer;
328 len = strlen(p_tmp);
329 buf_size = sizeof(tmpbuffer) - (p_tmp - tmpbuffer);
330 count = kallsyms_symbol_complete(p_tmp, buf_size);
331 if (tab == 2 && count > 0) {
332 kdb_printf("\n%d symbols are found.", count);
333 if (count > dtab_count) {
334 count = dtab_count;
335 kdb_printf(" But only first %d symbols will"
336 " be printed.\nYou can change the"
337 " environment variable DTABCOUNT.",
338 count);
339 }
340 kdb_printf("\n");
341 for (i = 0; i < count; i++) {
342 ret = kallsyms_symbol_next(p_tmp, i, buf_size);
343 if (WARN_ON(!ret))
344 break;
345 if (ret != -E2BIG)
346 kdb_printf("%s ", p_tmp);
347 else
348 kdb_printf("%s... ", p_tmp);
349 *(p_tmp + len) = '\0';
350 }
351 if (i >= dtab_count)
352 kdb_printf("...");
353 kdb_printf("\n");
354 kdb_printf(kdb_prompt_str);
355 kdb_printf("%s", buffer);
356 } else if (tab != 2 && count > 0) {
357 len_tmp = strlen(p_tmp);
358 strncpy(p_tmp+len_tmp, cp, lastchar-cp+1);
359 len_tmp = strlen(p_tmp);
360 strncpy(cp, p_tmp+len, len_tmp-len + 1);
361 len = len_tmp - len;
362 kdb_printf("%s", cp);
363 cp += len;
364 lastchar += len;
365 }
366 kdb_nextline = 1; /* reset output line number */
367 break;
368 default:
369 if (key >= 32 && lastchar < bufend) {
370 if (cp < lastchar) {
371 memcpy(tmpbuffer, cp, lastchar - cp);
372 memcpy(cp+1, tmpbuffer, lastchar - cp);
373 *++lastchar = '\0';
374 *cp = key;
375 kdb_printf("%s\r", cp);
376 ++cp;
377 tmp = *cp;
378 *cp = '\0';
379 kdb_printf(kdb_prompt_str);
380 kdb_printf("%s", buffer);
381 *cp = tmp;
382 } else {
383 *++lastchar = '\0';
384 *cp++ = key;
385 /* The kgdb transition check will hide
386 * printed characters if we think that
387 * kgdb is connecting, until the check
388 * fails */
389 if (!KDB_STATE(KGDB_TRANS)) {
390 if (kgdb_transition_check(buffer))
391 return buffer;
392 } else {
393 kdb_printf("%c", key);
394 }
395 }
396 /* Special escape to kgdb */
397 if (lastchar - buffer >= 5 &&
398 strcmp(lastchar - 5, "$?#3f") == 0) {
399 kdb_gdb_state_pass(lastchar - 5);
400 strcpy(buffer, "kgdb");
401 KDB_STATE_SET(DOING_KGDB);
402 return buffer;
403 }
404 if (lastchar - buffer >= 11 &&
405 strcmp(lastchar - 11, "$qSupported") == 0) {
406 kdb_gdb_state_pass(lastchar - 11);
407 strcpy(buffer, "kgdb");
408 KDB_STATE_SET(DOING_KGDB);
409 return buffer;
410 }
411 }
412 break;
413 }
414 goto poll_again;
415 }
416
417 /*
418 * kdb_getstr
419 *
420 * Print the prompt string and read a command from the
421 * input device.
422 *
423 * Parameters:
424 * buffer Address of buffer to receive command
425 * bufsize Size of buffer in bytes
426 * prompt Pointer to string to use as prompt string
427 * Returns:
428 * Pointer to command buffer.
429 * Locking:
430 * None.
431 * Remarks:
432 * For SMP kernels, the processor number will be
433 * substituted for %d, %x or %o in the prompt.
434 */
435
kdb_getstr(char * buffer,size_t bufsize,const char * prompt)436 char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
437 {
438 if (prompt && kdb_prompt_str != prompt)
439 strscpy(kdb_prompt_str, prompt, CMD_BUFLEN);
440 kdb_printf(kdb_prompt_str);
441 kdb_nextline = 1; /* Prompt and input resets line number */
442 return kdb_read(buffer, bufsize);
443 }
444
445 /*
446 * kdb_input_flush
447 *
448 * Get rid of any buffered console input.
449 *
450 * Parameters:
451 * none
452 * Returns:
453 * nothing
454 * Locking:
455 * none
456 * Remarks:
457 * Call this function whenever you want to flush input. If there is any
458 * outstanding input, it ignores all characters until there has been no
459 * data for approximately 1ms.
460 */
461
kdb_input_flush(void)462 static void kdb_input_flush(void)
463 {
464 get_char_func *f;
465 int res;
466 int flush_delay = 1;
467 while (flush_delay) {
468 flush_delay--;
469 empty:
470 touch_nmi_watchdog();
471 for (f = &kdb_poll_funcs[0]; *f; ++f) {
472 res = (*f)();
473 if (res != -1) {
474 flush_delay = 1;
475 goto empty;
476 }
477 }
478 if (flush_delay)
479 mdelay(1);
480 }
481 }
482
483 /*
484 * kdb_printf
485 *
486 * Print a string to the output device(s).
487 *
488 * Parameters:
489 * printf-like format and optional args.
490 * Returns:
491 * 0
492 * Locking:
493 * None.
494 * Remarks:
495 * use 'kdbcons->write()' to avoid polluting 'log_buf' with
496 * kdb output.
497 *
498 * If the user is doing a cmd args | grep srch
499 * then kdb_grepping_flag is set.
500 * In that case we need to accumulate full lines (ending in \n) before
501 * searching for the pattern.
502 */
503
504 static char kdb_buffer[256]; /* A bit too big to go on stack */
505 static char *next_avail = kdb_buffer;
506 static int size_avail;
507 static int suspend_grep;
508
509 /*
510 * search arg1 to see if it contains arg2
511 * (kdmain.c provides flags for ^pat and pat$)
512 *
513 * return 1 for found, 0 for not found
514 */
kdb_search_string(char * searched,char * searchfor)515 static int kdb_search_string(char *searched, char *searchfor)
516 {
517 char firstchar, *cp;
518 int len1, len2;
519
520 /* not counting the newline at the end of "searched" */
521 len1 = strlen(searched)-1;
522 len2 = strlen(searchfor);
523 if (len1 < len2)
524 return 0;
525 if (kdb_grep_leading && kdb_grep_trailing && len1 != len2)
526 return 0;
527 if (kdb_grep_leading) {
528 if (!strncmp(searched, searchfor, len2))
529 return 1;
530 } else if (kdb_grep_trailing) {
531 if (!strncmp(searched+len1-len2, searchfor, len2))
532 return 1;
533 } else {
534 firstchar = *searchfor;
535 cp = searched;
536 while ((cp = strchr(cp, firstchar))) {
537 if (!strncmp(cp, searchfor, len2))
538 return 1;
539 cp++;
540 }
541 }
542 return 0;
543 }
544
kdb_msg_write(const char * msg,int msg_len)545 static void kdb_msg_write(const char *msg, int msg_len)
546 {
547 struct console *c;
548 const char *cp;
549 int len;
550
551 if (msg_len == 0)
552 return;
553
554 cp = msg;
555 len = msg_len;
556
557 while (len--) {
558 dbg_io_ops->write_char(*cp);
559 cp++;
560 }
561
562 for_each_console(c) {
563 if (!(c->flags & CON_ENABLED))
564 continue;
565 if (c == dbg_io_ops->cons)
566 continue;
567 /*
568 * Set oops_in_progress to encourage the console drivers to
569 * disregard their internal spin locks: in the current calling
570 * context the risk of deadlock is a bigger problem than risks
571 * due to re-entering the console driver. We operate directly on
572 * oops_in_progress rather than using bust_spinlocks() because
573 * the calls bust_spinlocks() makes on exit are not appropriate
574 * for this calling context.
575 */
576 ++oops_in_progress;
577 c->write(c, msg, msg_len);
578 --oops_in_progress;
579 touch_nmi_watchdog();
580 }
581 }
582
vkdb_printf(enum kdb_msgsrc src,const char * fmt,va_list ap)583 int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
584 {
585 int diag;
586 int linecount;
587 int colcount;
588 int logging, saved_loglevel = 0;
589 int retlen = 0;
590 int fnd, len;
591 int this_cpu, old_cpu;
592 char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
593 char *moreprompt = "more> ";
594 unsigned long flags;
595
596 /* Serialize kdb_printf if multiple cpus try to write at once.
597 * But if any cpu goes recursive in kdb, just print the output,
598 * even if it is interleaved with any other text.
599 */
600 local_irq_save(flags);
601 this_cpu = smp_processor_id();
602 for (;;) {
603 old_cpu = cmpxchg(&kdb_printf_cpu, -1, this_cpu);
604 if (old_cpu == -1 || old_cpu == this_cpu)
605 break;
606
607 cpu_relax();
608 }
609
610 diag = kdbgetintenv("LINES", &linecount);
611 if (diag || linecount <= 1)
612 linecount = 24;
613
614 diag = kdbgetintenv("COLUMNS", &colcount);
615 if (diag || colcount <= 1)
616 colcount = 80;
617
618 diag = kdbgetintenv("LOGGING", &logging);
619 if (diag)
620 logging = 0;
621
622 if (!kdb_grepping_flag || suspend_grep) {
623 /* normally, every vsnprintf starts a new buffer */
624 next_avail = kdb_buffer;
625 size_avail = sizeof(kdb_buffer);
626 }
627 vsnprintf(next_avail, size_avail, fmt, ap);
628
629 /*
630 * If kdb_parse() found that the command was cmd xxx | grep yyy
631 * then kdb_grepping_flag is set, and kdb_grep_string contains yyy
632 *
633 * Accumulate the print data up to a newline before searching it.
634 * (vsnprintf does null-terminate the string that it generates)
635 */
636
637 /* skip the search if prints are temporarily unconditional */
638 if (!suspend_grep && kdb_grepping_flag) {
639 cp = strchr(kdb_buffer, '\n');
640 if (!cp) {
641 /*
642 * Special cases that don't end with newlines
643 * but should be written without one:
644 * The "[nn]kdb> " prompt should
645 * appear at the front of the buffer.
646 *
647 * The "[nn]more " prompt should also be
648 * (MOREPROMPT -> moreprompt)
649 * written * but we print that ourselves,
650 * we set the suspend_grep flag to make
651 * it unconditional.
652 *
653 */
654 if (next_avail == kdb_buffer) {
655 /*
656 * these should occur after a newline,
657 * so they will be at the front of the
658 * buffer
659 */
660 cp2 = kdb_buffer;
661 len = strlen(kdb_prompt_str);
662 if (!strncmp(cp2, kdb_prompt_str, len)) {
663 /*
664 * We're about to start a new
665 * command, so we can go back
666 * to normal mode.
667 */
668 kdb_grepping_flag = 0;
669 goto kdb_printit;
670 }
671 }
672 /* no newline; don't search/write the buffer
673 until one is there */
674 len = strlen(kdb_buffer);
675 next_avail = kdb_buffer + len;
676 size_avail = sizeof(kdb_buffer) - len;
677 goto kdb_print_out;
678 }
679
680 /*
681 * The newline is present; print through it or discard
682 * it, depending on the results of the search.
683 */
684 cp++; /* to byte after the newline */
685 replaced_byte = *cp; /* remember what/where it was */
686 cphold = cp;
687 *cp = '\0'; /* end the string for our search */
688
689 /*
690 * We now have a newline at the end of the string
691 * Only continue with this output if it contains the
692 * search string.
693 */
694 fnd = kdb_search_string(kdb_buffer, kdb_grep_string);
695 if (!fnd) {
696 /*
697 * At this point the complete line at the start
698 * of kdb_buffer can be discarded, as it does
699 * not contain what the user is looking for.
700 * Shift the buffer left.
701 */
702 *cphold = replaced_byte;
703 strcpy(kdb_buffer, cphold);
704 len = strlen(kdb_buffer);
705 next_avail = kdb_buffer + len;
706 size_avail = sizeof(kdb_buffer) - len;
707 goto kdb_print_out;
708 }
709 if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH) {
710 /*
711 * This was a interactive search (using '/' at more
712 * prompt) and it has completed. Replace the \0 with
713 * its original value to ensure multi-line strings
714 * are handled properly, and return to normal mode.
715 */
716 *cphold = replaced_byte;
717 kdb_grepping_flag = 0;
718 }
719 /*
720 * at this point the string is a full line and
721 * should be printed, up to the null.
722 */
723 }
724 kdb_printit:
725
726 /*
727 * Write to all consoles.
728 */
729 retlen = strlen(kdb_buffer);
730 cp = (char *) printk_skip_headers(kdb_buffer);
731 if (!dbg_kdb_mode && kgdb_connected)
732 gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
733 else
734 kdb_msg_write(cp, retlen - (cp - kdb_buffer));
735
736 if (logging) {
737 saved_loglevel = console_loglevel;
738 console_loglevel = CONSOLE_LOGLEVEL_SILENT;
739 if (printk_get_level(kdb_buffer) || src == KDB_MSGSRC_PRINTK)
740 printk("%s", kdb_buffer);
741 else
742 pr_info("%s", kdb_buffer);
743 }
744
745 if (KDB_STATE(PAGER)) {
746 /*
747 * Check printed string to decide how to bump the
748 * kdb_nextline to control when the more prompt should
749 * show up.
750 */
751 int got = 0;
752 len = retlen;
753 while (len--) {
754 if (kdb_buffer[len] == '\n') {
755 kdb_nextline++;
756 got = 0;
757 } else if (kdb_buffer[len] == '\r') {
758 got = 0;
759 } else {
760 got++;
761 }
762 }
763 kdb_nextline += got / (colcount + 1);
764 }
765
766 /* check for having reached the LINES number of printed lines */
767 if (kdb_nextline >= linecount) {
768 char ch;
769
770 /* Watch out for recursion here. Any routine that calls
771 * kdb_printf will come back through here. And kdb_read
772 * uses kdb_printf to echo on serial consoles ...
773 */
774 kdb_nextline = 1; /* In case of recursion */
775
776 /*
777 * Pause until cr.
778 */
779 moreprompt = kdbgetenv("MOREPROMPT");
780 if (moreprompt == NULL)
781 moreprompt = "more> ";
782
783 kdb_input_flush();
784 kdb_msg_write(moreprompt, strlen(moreprompt));
785
786 if (logging)
787 printk("%s", moreprompt);
788
789 ch = kdb_getchar();
790 kdb_nextline = 1; /* Really set output line 1 */
791
792 /* empty and reset the buffer: */
793 kdb_buffer[0] = '\0';
794 next_avail = kdb_buffer;
795 size_avail = sizeof(kdb_buffer);
796 if ((ch == 'q') || (ch == 'Q')) {
797 /* user hit q or Q */
798 KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */
799 KDB_STATE_CLEAR(PAGER);
800 /* end of command output; back to normal mode */
801 kdb_grepping_flag = 0;
802 kdb_printf("\n");
803 } else if (ch == ' ') {
804 kdb_printf("\r");
805 suspend_grep = 1; /* for this recursion */
806 } else if (ch == '\n' || ch == '\r') {
807 kdb_nextline = linecount - 1;
808 kdb_printf("\r");
809 suspend_grep = 1; /* for this recursion */
810 } else if (ch == '/' && !kdb_grepping_flag) {
811 kdb_printf("\r");
812 kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
813 kdbgetenv("SEARCHPROMPT") ?: "search> ");
814 *strchrnul(kdb_grep_string, '\n') = '\0';
815 kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
816 suspend_grep = 1; /* for this recursion */
817 } else if (ch) {
818 /* user hit something unexpected */
819 suspend_grep = 1; /* for this recursion */
820 if (ch != '/')
821 kdb_printf(
822 "\nOnly 'q', 'Q' or '/' are processed at "
823 "more prompt, input ignored\n");
824 else
825 kdb_printf("\n'/' cannot be used during | "
826 "grep filtering, input ignored\n");
827 } else if (kdb_grepping_flag) {
828 /* user hit enter */
829 suspend_grep = 1; /* for this recursion */
830 kdb_printf("\n");
831 }
832 kdb_input_flush();
833 }
834
835 /*
836 * For grep searches, shift the printed string left.
837 * replaced_byte contains the character that was overwritten with
838 * the terminating null, and cphold points to the null.
839 * Then adjust the notion of available space in the buffer.
840 */
841 if (kdb_grepping_flag && !suspend_grep) {
842 *cphold = replaced_byte;
843 strcpy(kdb_buffer, cphold);
844 len = strlen(kdb_buffer);
845 next_avail = kdb_buffer + len;
846 size_avail = sizeof(kdb_buffer) - len;
847 }
848
849 kdb_print_out:
850 suspend_grep = 0; /* end of what may have been a recursive call */
851 if (logging)
852 console_loglevel = saved_loglevel;
853 /* kdb_printf_cpu locked the code above. */
854 smp_store_release(&kdb_printf_cpu, old_cpu);
855 local_irq_restore(flags);
856 return retlen;
857 }
858
kdb_printf(const char * fmt,...)859 int kdb_printf(const char *fmt, ...)
860 {
861 va_list ap;
862 int r;
863
864 va_start(ap, fmt);
865 r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap);
866 va_end(ap);
867
868 return r;
869 }
870 EXPORT_SYMBOL_GPL(kdb_printf);
871