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/types.h>
13 #include <linux/ctype.h>
14 #include <linux/kernel.h>
15 #include <linux/init.h>
16 #include <linux/kdev_t.h>
17 #include <linux/console.h>
18 #include <linux/string.h>
19 #include <linux/sched.h>
20 #include <linux/smp.h>
21 #include <linux/nmi.h>
22 #include <linux/delay.h>
23 #include <linux/kgdb.h>
24 #include <linux/kdb.h>
25 #include <linux/kallsyms.h>
26 #include "kdb_private.h"
27
28 #define CMD_BUFLEN 256
29 char kdb_prompt_str[CMD_BUFLEN];
30
31 int kdb_trap_printk;
32 int kdb_printf_cpu = -1;
33
kgdb_transition_check(char * buffer)34 static int kgdb_transition_check(char *buffer)
35 {
36 if (buffer[0] != '+' && buffer[0] != '$') {
37 KDB_STATE_SET(KGDB_TRANS);
38 kdb_printf("%s", buffer);
39 } else {
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);
45 return 1;
46 }
47 }
48 return 0;
49 }
50
51 /**
52 * kdb_handle_escape() - validity check on an accumulated escape sequence.
53 * @buf: Accumulated escape characters to be examined. Note that buf
54 * is not a string, it is an array of characters and need not be
55 * nil terminated.
56 * @sz: Number of accumulated escape characters.
57 *
58 * Return: -1 if the escape sequence is unwanted, 0 if it is incomplete,
59 * otherwise it returns a mapped key value to pass to the upper layers.
60 */
kdb_handle_escape(char * buf,size_t sz)61 static int kdb_handle_escape(char *buf, size_t sz)
62 {
63 char *lastkey = buf + sz - 1;
64
65 switch (sz) {
66 case 1:
67 if (*lastkey == '\e')
68 return 0;
69 break;
70
71 case 2: /* \e<something> */
72 if (*lastkey == '[')
73 return 0;
74 break;
75
76 case 3:
77 switch (*lastkey) {
78 case 'A': /* \e[A, up arrow */
79 return 16;
80 case 'B': /* \e[B, down arrow */
81 return 14;
82 case 'C': /* \e[C, right arrow */
83 return 6;
84 case 'D': /* \e[D, left arrow */
85 return 2;
86 case '1': /* \e[<1,3,4>], may be home, del, end */
87 case '3':
88 case '4':
89 return 0;
90 }
91 break;
92
93 case 4:
94 if (*lastkey == '~') {
95 switch (buf[2]) {
96 case '1': /* \e[1~, home */
97 return 1;
98 case '3': /* \e[3~, del */
99 return 4;
100 case '4': /* \e[4~, end */
101 return 5;
102 }
103 }
104 break;
105 }
106
107 return -1;
108 }
109
110 /**
111 * kdb_getchar() - Read a single character from a kdb console (or consoles).
112 *
113 * Other than polling the various consoles that are currently enabled,
114 * most of the work done in this function is dealing with escape sequences.
115 *
116 * An escape key could be the start of a vt100 control sequence such as \e[D
117 * (left arrow) or it could be a character in its own right. The standard
118 * method for detecting the difference is to wait for 2 seconds to see if there
119 * are any other characters. kdb is complicated by the lack of a timer service
120 * (interrupts are off), by multiple input sources. Escape sequence processing
121 * has to be done as states in the polling loop.
122 *
123 * Return: The key pressed or a control code derived from an escape sequence.
124 */
kdb_getchar(void)125 char kdb_getchar(void)
126 {
127 #define ESCAPE_UDELAY 1000
128 #define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
129 char buf[4]; /* longest vt100 escape sequence is 4 bytes */
130 char *pbuf = buf;
131 int escape_delay = 0;
132 get_char_func *f, *f_prev = NULL;
133 int key;
134
135 for (f = &kdb_poll_funcs[0]; ; ++f) {
136 if (*f == NULL) {
137 /* Reset NMI watchdog once per poll loop */
138 touch_nmi_watchdog();
139 f = &kdb_poll_funcs[0];
140 }
141
142 key = (*f)();
143 if (key == -1) {
144 if (escape_delay) {
145 udelay(ESCAPE_UDELAY);
146 if (--escape_delay == 0)
147 return '\e';
148 }
149 continue;
150 }
151
152 /*
153 * When the first character is received (or we get a change
154 * input source) we set ourselves up to handle an escape
155 * sequences (just in case).
156 */
157 if (f_prev != f) {
158 f_prev = f;
159 pbuf = buf;
160 escape_delay = ESCAPE_DELAY;
161 }
162
163 *pbuf++ = key;
164 key = kdb_handle_escape(buf, pbuf - buf);
165 if (key < 0) /* no escape sequence; return best character */
166 return buf[pbuf - buf == 2 ? 1 : 0];
167 if (key > 0)
168 return key;
169 }
170
171 unreachable();
172 }
173
174 /*
175 * kdb_read
176 *
177 * This function reads a string of characters, terminated by
178 * a newline, or by reaching the end of the supplied buffer,
179 * from the current kernel debugger console device.
180 * Parameters:
181 * buffer - Address of character buffer to receive input characters.
182 * bufsize - size, in bytes, of the character buffer
183 * Returns:
184 * Returns a pointer to the buffer containing the received
185 * character string. This string will be terminated by a
186 * newline character.
187 * Locking:
188 * No locks are required to be held upon entry to this
189 * function. It is not reentrant - it relies on the fact
190 * that while kdb is running on only one "master debug" cpu.
191 * Remarks:
192 * The buffer size must be >= 2.
193 */
194
kdb_read(char * buffer,size_t bufsize)195 static char *kdb_read(char *buffer, size_t bufsize)
196 {
197 char *cp = buffer;
198 char *bufend = buffer+bufsize-2; /* Reserve space for newline
199 * and null byte */
200 char *lastchar;
201 char *p_tmp;
202 char tmp;
203 static char tmpbuffer[CMD_BUFLEN];
204 int len = strlen(buffer);
205 int len_tmp;
206 int tab = 0;
207 int count;
208 int i;
209 int diag, dtab_count;
210 int key, buf_size, ret;
211
212
213 diag = kdbgetintenv("DTABCOUNT", &dtab_count);
214 if (diag)
215 dtab_count = 30;
216
217 if (len > 0) {
218 cp += len;
219 if (*(buffer+len-1) == '\n')
220 cp--;
221 }
222
223 lastchar = cp;
224 *cp = '\0';
225 kdb_printf("%s", buffer);
226 poll_again:
227 key = kdb_getchar();
228 if (key != 9)
229 tab = 0;
230 switch (key) {
231 case 8: /* backspace */
232 if (cp > buffer) {
233 if (cp < lastchar) {
234 memcpy(tmpbuffer, cp, lastchar - cp);
235 memcpy(cp-1, tmpbuffer, lastchar - cp);
236 }
237 *(--lastchar) = '\0';
238 --cp;
239 kdb_printf("\b%s \r", cp);
240 tmp = *cp;
241 *cp = '\0';
242 kdb_printf(kdb_prompt_str);
243 kdb_printf("%s", buffer);
244 *cp = tmp;
245 }
246 break;
247 case 13: /* enter */
248 *lastchar++ = '\n';
249 *lastchar++ = '\0';
250 if (!KDB_STATE(KGDB_TRANS)) {
251 KDB_STATE_SET(KGDB_TRANS);
252 kdb_printf("%s", buffer);
253 }
254 kdb_printf("\n");
255 return buffer;
256 case 4: /* Del */
257 if (cp < lastchar) {
258 memcpy(tmpbuffer, cp+1, lastchar - cp - 1);
259 memcpy(cp, tmpbuffer, lastchar - cp - 1);
260 *(--lastchar) = '\0';
261 kdb_printf("%s \r", cp);
262 tmp = *cp;
263 *cp = '\0';
264 kdb_printf(kdb_prompt_str);
265 kdb_printf("%s", buffer);
266 *cp = tmp;
267 }
268 break;
269 case 1: /* Home */
270 if (cp > buffer) {
271 kdb_printf("\r");
272 kdb_printf(kdb_prompt_str);
273 cp = buffer;
274 }
275 break;
276 case 5: /* End */
277 if (cp < lastchar) {
278 kdb_printf("%s", cp);
279 cp = lastchar;
280 }
281 break;
282 case 2: /* Left */
283 if (cp > buffer) {
284 kdb_printf("\b");
285 --cp;
286 }
287 break;
288 case 14: /* Down */
289 memset(tmpbuffer, ' ',
290 strlen(kdb_prompt_str) + (lastchar-buffer));
291 *(tmpbuffer+strlen(kdb_prompt_str) +
292 (lastchar-buffer)) = '\0';
293 kdb_printf("\r%s\r", tmpbuffer);
294 *lastchar = (char)key;
295 *(lastchar+1) = '\0';
296 return lastchar;
297 case 6: /* Right */
298 if (cp < lastchar) {
299 kdb_printf("%c", *cp);
300 ++cp;
301 }
302 break;
303 case 16: /* Up */
304 memset(tmpbuffer, ' ',
305 strlen(kdb_prompt_str) + (lastchar-buffer));
306 *(tmpbuffer+strlen(kdb_prompt_str) +
307 (lastchar-buffer)) = '\0';
308 kdb_printf("\r%s\r", tmpbuffer);
309 *lastchar = (char)key;
310 *(lastchar+1) = '\0';
311 return lastchar;
312 case 9: /* Tab */
313 if (tab < 2)
314 ++tab;
315 p_tmp = buffer;
316 while (*p_tmp == ' ')
317 p_tmp++;
318 if (p_tmp > cp)
319 break;
320 memcpy(tmpbuffer, p_tmp, cp-p_tmp);
321 *(tmpbuffer + (cp-p_tmp)) = '\0';
322 p_tmp = strrchr(tmpbuffer, ' ');
323 if (p_tmp)
324 ++p_tmp;
325 else
326 p_tmp = tmpbuffer;
327 len = strlen(p_tmp);
328 buf_size = sizeof(tmpbuffer) - (p_tmp - tmpbuffer);
329 count = kallsyms_symbol_complete(p_tmp, buf_size);
330 if (tab == 2 && count > 0) {
331 kdb_printf("\n%d symbols are found.", count);
332 if (count > dtab_count) {
333 count = dtab_count;
334 kdb_printf(" But only first %d symbols will"
335 " be printed.\nYou can change the"
336 " environment variable DTABCOUNT.",
337 count);
338 }
339 kdb_printf("\n");
340 for (i = 0; i < count; i++) {
341 ret = kallsyms_symbol_next(p_tmp, i, buf_size);
342 if (WARN_ON(!ret))
343 break;
344 if (ret != -E2BIG)
345 kdb_printf("%s ", p_tmp);
346 else
347 kdb_printf("%s... ", p_tmp);
348 *(p_tmp + len) = '\0';
349 }
350 if (i >= dtab_count)
351 kdb_printf("...");
352 kdb_printf("\n");
353 kdb_printf(kdb_prompt_str);
354 kdb_printf("%s", buffer);
355 } else if (tab != 2 && count > 0) {
356 len_tmp = strlen(p_tmp);
357 strncpy(p_tmp+len_tmp, cp, lastchar-cp+1);
358 len_tmp = strlen(p_tmp);
359 strncpy(cp, p_tmp+len, len_tmp-len + 1);
360 len = len_tmp - len;
361 kdb_printf("%s", cp);
362 cp += len;
363 lastchar += len;
364 }
365 kdb_nextline = 1; /* reset output line number */
366 break;
367 default:
368 if (key >= 32 && lastchar < bufend) {
369 if (cp < lastchar) {
370 memcpy(tmpbuffer, cp, lastchar - cp);
371 memcpy(cp+1, tmpbuffer, lastchar - cp);
372 *++lastchar = '\0';
373 *cp = key;
374 kdb_printf("%s\r", cp);
375 ++cp;
376 tmp = *cp;
377 *cp = '\0';
378 kdb_printf(kdb_prompt_str);
379 kdb_printf("%s", buffer);
380 *cp = tmp;
381 } else {
382 *++lastchar = '\0';
383 *cp++ = key;
384 /* The kgdb transition check will hide
385 * printed characters if we think that
386 * kgdb is connecting, until the check
387 * fails */
388 if (!KDB_STATE(KGDB_TRANS)) {
389 if (kgdb_transition_check(buffer))
390 return buffer;
391 } else {
392 kdb_printf("%c", key);
393 }
394 }
395 /* Special escape to kgdb */
396 if (lastchar - buffer >= 5 &&
397 strcmp(lastchar - 5, "$?#3f") == 0) {
398 kdb_gdb_state_pass(lastchar - 5);
399 strcpy(buffer, "kgdb");
400 KDB_STATE_SET(DOING_KGDB);
401 return buffer;
402 }
403 if (lastchar - buffer >= 11 &&
404 strcmp(lastchar - 11, "$qSupported") == 0) {
405 kdb_gdb_state_pass(lastchar - 11);
406 strcpy(buffer, "kgdb");
407 KDB_STATE_SET(DOING_KGDB);
408 return buffer;
409 }
410 }
411 break;
412 }
413 goto poll_again;
414 }
415
416 /*
417 * kdb_getstr
418 *
419 * Print the prompt string and read a command from the
420 * input device.
421 *
422 * Parameters:
423 * buffer Address of buffer to receive command
424 * bufsize Size of buffer in bytes
425 * prompt Pointer to string to use as prompt string
426 * Returns:
427 * Pointer to command buffer.
428 * Locking:
429 * None.
430 * Remarks:
431 * For SMP kernels, the processor number will be
432 * substituted for %d, %x or %o in the prompt.
433 */
434
kdb_getstr(char * buffer,size_t bufsize,const char * prompt)435 char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
436 {
437 if (prompt && kdb_prompt_str != prompt)
438 strscpy(kdb_prompt_str, prompt, CMD_BUFLEN);
439 kdb_printf(kdb_prompt_str);
440 kdb_nextline = 1; /* Prompt and input resets line number */
441 return kdb_read(buffer, bufsize);
442 }
443
444 /*
445 * kdb_input_flush
446 *
447 * Get rid of any buffered console input.
448 *
449 * Parameters:
450 * none
451 * Returns:
452 * nothing
453 * Locking:
454 * none
455 * Remarks:
456 * Call this function whenever you want to flush input. If there is any
457 * outstanding input, it ignores all characters until there has been no
458 * data for approximately 1ms.
459 */
460
kdb_input_flush(void)461 static void kdb_input_flush(void)
462 {
463 get_char_func *f;
464 int res;
465 int flush_delay = 1;
466 while (flush_delay) {
467 flush_delay--;
468 empty:
469 touch_nmi_watchdog();
470 for (f = &kdb_poll_funcs[0]; *f; ++f) {
471 res = (*f)();
472 if (res != -1) {
473 flush_delay = 1;
474 goto empty;
475 }
476 }
477 if (flush_delay)
478 mdelay(1);
479 }
480 }
481
482 /*
483 * kdb_printf
484 *
485 * Print a string to the output device(s).
486 *
487 * Parameters:
488 * printf-like format and optional args.
489 * Returns:
490 * 0
491 * Locking:
492 * None.
493 * Remarks:
494 * use 'kdbcons->write()' to avoid polluting 'log_buf' with
495 * kdb output.
496 *
497 * If the user is doing a cmd args | grep srch
498 * then kdb_grepping_flag is set.
499 * In that case we need to accumulate full lines (ending in \n) before
500 * searching for the pattern.
501 */
502
503 static char kdb_buffer[256]; /* A bit too big to go on stack */
504 static char *next_avail = kdb_buffer;
505 static int size_avail;
506 static int suspend_grep;
507
508 /*
509 * search arg1 to see if it contains arg2
510 * (kdmain.c provides flags for ^pat and pat$)
511 *
512 * return 1 for found, 0 for not found
513 */
kdb_search_string(char * searched,char * searchfor)514 static int kdb_search_string(char *searched, char *searchfor)
515 {
516 char firstchar, *cp;
517 int len1, len2;
518
519 /* not counting the newline at the end of "searched" */
520 len1 = strlen(searched)-1;
521 len2 = strlen(searchfor);
522 if (len1 < len2)
523 return 0;
524 if (kdb_grep_leading && kdb_grep_trailing && len1 != len2)
525 return 0;
526 if (kdb_grep_leading) {
527 if (!strncmp(searched, searchfor, len2))
528 return 1;
529 } else if (kdb_grep_trailing) {
530 if (!strncmp(searched+len1-len2, searchfor, len2))
531 return 1;
532 } else {
533 firstchar = *searchfor;
534 cp = searched;
535 while ((cp = strchr(cp, firstchar))) {
536 if (!strncmp(cp, searchfor, len2))
537 return 1;
538 cp++;
539 }
540 }
541 return 0;
542 }
543
kdb_msg_write(const char * msg,int msg_len)544 static void kdb_msg_write(const char *msg, int msg_len)
545 {
546 struct console *c;
547 const char *cp;
548 int cookie;
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 /*
563 * The console_srcu_read_lock() only provides safe console list
564 * traversal. The use of the ->write() callback relies on all other
565 * CPUs being stopped at the moment and console drivers being able to
566 * handle reentrance when @oops_in_progress is set.
567 *
568 * There is no guarantee that every console driver can handle
569 * reentrance in this way; the developer deploying the debugger
570 * is responsible for ensuring that the console drivers they
571 * have selected handle reentrance appropriately.
572 */
573 cookie = console_srcu_read_lock();
574 for_each_console_srcu(c) {
575 if (!(console_srcu_read_flags(c) & CON_ENABLED))
576 continue;
577 if (c == dbg_io_ops->cons)
578 continue;
579 /*
580 * Set oops_in_progress to encourage the console drivers to
581 * disregard their internal spin locks: in the current calling
582 * context the risk of deadlock is a bigger problem than risks
583 * due to re-entering the console driver. We operate directly on
584 * oops_in_progress rather than using bust_spinlocks() because
585 * the calls bust_spinlocks() makes on exit are not appropriate
586 * for this calling context.
587 */
588 ++oops_in_progress;
589 c->write(c, msg, msg_len);
590 --oops_in_progress;
591 touch_nmi_watchdog();
592 }
593 console_srcu_read_unlock(cookie);
594 }
595
vkdb_printf(enum kdb_msgsrc src,const char * fmt,va_list ap)596 int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
597 {
598 int diag;
599 int linecount;
600 int colcount;
601 int logging, saved_loglevel = 0;
602 int retlen = 0;
603 int fnd, len;
604 int this_cpu, old_cpu;
605 char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
606 char *moreprompt = "more> ";
607 unsigned long flags;
608
609 /* Serialize kdb_printf if multiple cpus try to write at once.
610 * But if any cpu goes recursive in kdb, just print the output,
611 * even if it is interleaved with any other text.
612 */
613 local_irq_save(flags);
614 this_cpu = smp_processor_id();
615 for (;;) {
616 old_cpu = cmpxchg(&kdb_printf_cpu, -1, this_cpu);
617 if (old_cpu == -1 || old_cpu == this_cpu)
618 break;
619
620 cpu_relax();
621 }
622
623 diag = kdbgetintenv("LINES", &linecount);
624 if (diag || linecount <= 1)
625 linecount = 24;
626
627 diag = kdbgetintenv("COLUMNS", &colcount);
628 if (diag || colcount <= 1)
629 colcount = 80;
630
631 diag = kdbgetintenv("LOGGING", &logging);
632 if (diag)
633 logging = 0;
634
635 if (!kdb_grepping_flag || suspend_grep) {
636 /* normally, every vsnprintf starts a new buffer */
637 next_avail = kdb_buffer;
638 size_avail = sizeof(kdb_buffer);
639 }
640 vsnprintf(next_avail, size_avail, fmt, ap);
641
642 /*
643 * If kdb_parse() found that the command was cmd xxx | grep yyy
644 * then kdb_grepping_flag is set, and kdb_grep_string contains yyy
645 *
646 * Accumulate the print data up to a newline before searching it.
647 * (vsnprintf does null-terminate the string that it generates)
648 */
649
650 /* skip the search if prints are temporarily unconditional */
651 if (!suspend_grep && kdb_grepping_flag) {
652 cp = strchr(kdb_buffer, '\n');
653 if (!cp) {
654 /*
655 * Special cases that don't end with newlines
656 * but should be written without one:
657 * The "[nn]kdb> " prompt should
658 * appear at the front of the buffer.
659 *
660 * The "[nn]more " prompt should also be
661 * (MOREPROMPT -> moreprompt)
662 * written * but we print that ourselves,
663 * we set the suspend_grep flag to make
664 * it unconditional.
665 *
666 */
667 if (next_avail == kdb_buffer) {
668 /*
669 * these should occur after a newline,
670 * so they will be at the front of the
671 * buffer
672 */
673 cp2 = kdb_buffer;
674 len = strlen(kdb_prompt_str);
675 if (!strncmp(cp2, kdb_prompt_str, len)) {
676 /*
677 * We're about to start a new
678 * command, so we can go back
679 * to normal mode.
680 */
681 kdb_grepping_flag = 0;
682 goto kdb_printit;
683 }
684 }
685 /* no newline; don't search/write the buffer
686 until one is there */
687 len = strlen(kdb_buffer);
688 next_avail = kdb_buffer + len;
689 size_avail = sizeof(kdb_buffer) - len;
690 goto kdb_print_out;
691 }
692
693 /*
694 * The newline is present; print through it or discard
695 * it, depending on the results of the search.
696 */
697 cp++; /* to byte after the newline */
698 replaced_byte = *cp; /* remember what/where it was */
699 cphold = cp;
700 *cp = '\0'; /* end the string for our search */
701
702 /*
703 * We now have a newline at the end of the string
704 * Only continue with this output if it contains the
705 * search string.
706 */
707 fnd = kdb_search_string(kdb_buffer, kdb_grep_string);
708 if (!fnd) {
709 /*
710 * At this point the complete line at the start
711 * of kdb_buffer can be discarded, as it does
712 * not contain what the user is looking for.
713 * Shift the buffer left.
714 */
715 *cphold = replaced_byte;
716 strcpy(kdb_buffer, cphold);
717 len = strlen(kdb_buffer);
718 next_avail = kdb_buffer + len;
719 size_avail = sizeof(kdb_buffer) - len;
720 goto kdb_print_out;
721 }
722 if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH) {
723 /*
724 * This was a interactive search (using '/' at more
725 * prompt) and it has completed. Replace the \0 with
726 * its original value to ensure multi-line strings
727 * are handled properly, and return to normal mode.
728 */
729 *cphold = replaced_byte;
730 kdb_grepping_flag = 0;
731 }
732 /*
733 * at this point the string is a full line and
734 * should be printed, up to the null.
735 */
736 }
737 kdb_printit:
738
739 /*
740 * Write to all consoles.
741 */
742 retlen = strlen(kdb_buffer);
743 cp = (char *) printk_skip_headers(kdb_buffer);
744 if (!dbg_kdb_mode && kgdb_connected)
745 gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
746 else
747 kdb_msg_write(cp, retlen - (cp - kdb_buffer));
748
749 if (logging) {
750 saved_loglevel = console_loglevel;
751 console_loglevel = CONSOLE_LOGLEVEL_SILENT;
752 if (printk_get_level(kdb_buffer) || src == KDB_MSGSRC_PRINTK)
753 printk("%s", kdb_buffer);
754 else
755 pr_info("%s", kdb_buffer);
756 }
757
758 if (KDB_STATE(PAGER)) {
759 /*
760 * Check printed string to decide how to bump the
761 * kdb_nextline to control when the more prompt should
762 * show up.
763 */
764 int got = 0;
765 len = retlen;
766 while (len--) {
767 if (kdb_buffer[len] == '\n') {
768 kdb_nextline++;
769 got = 0;
770 } else if (kdb_buffer[len] == '\r') {
771 got = 0;
772 } else {
773 got++;
774 }
775 }
776 kdb_nextline += got / (colcount + 1);
777 }
778
779 /* check for having reached the LINES number of printed lines */
780 if (kdb_nextline >= linecount) {
781 char ch;
782
783 /* Watch out for recursion here. Any routine that calls
784 * kdb_printf will come back through here. And kdb_read
785 * uses kdb_printf to echo on serial consoles ...
786 */
787 kdb_nextline = 1; /* In case of recursion */
788
789 /*
790 * Pause until cr.
791 */
792 moreprompt = kdbgetenv("MOREPROMPT");
793 if (moreprompt == NULL)
794 moreprompt = "more> ";
795
796 kdb_input_flush();
797 kdb_msg_write(moreprompt, strlen(moreprompt));
798
799 if (logging)
800 printk("%s", moreprompt);
801
802 ch = kdb_getchar();
803 kdb_nextline = 1; /* Really set output line 1 */
804
805 /* empty and reset the buffer: */
806 kdb_buffer[0] = '\0';
807 next_avail = kdb_buffer;
808 size_avail = sizeof(kdb_buffer);
809 if ((ch == 'q') || (ch == 'Q')) {
810 /* user hit q or Q */
811 KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */
812 KDB_STATE_CLEAR(PAGER);
813 /* end of command output; back to normal mode */
814 kdb_grepping_flag = 0;
815 kdb_printf("\n");
816 } else if (ch == ' ') {
817 kdb_printf("\r");
818 suspend_grep = 1; /* for this recursion */
819 } else if (ch == '\n' || ch == '\r') {
820 kdb_nextline = linecount - 1;
821 kdb_printf("\r");
822 suspend_grep = 1; /* for this recursion */
823 } else if (ch == '/' && !kdb_grepping_flag) {
824 kdb_printf("\r");
825 kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
826 kdbgetenv("SEARCHPROMPT") ?: "search> ");
827 *strchrnul(kdb_grep_string, '\n') = '\0';
828 kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
829 suspend_grep = 1; /* for this recursion */
830 } else if (ch) {
831 /* user hit something unexpected */
832 suspend_grep = 1; /* for this recursion */
833 if (ch != '/')
834 kdb_printf(
835 "\nOnly 'q', 'Q' or '/' are processed at "
836 "more prompt, input ignored\n");
837 else
838 kdb_printf("\n'/' cannot be used during | "
839 "grep filtering, input ignored\n");
840 } else if (kdb_grepping_flag) {
841 /* user hit enter */
842 suspend_grep = 1; /* for this recursion */
843 kdb_printf("\n");
844 }
845 kdb_input_flush();
846 }
847
848 /*
849 * For grep searches, shift the printed string left.
850 * replaced_byte contains the character that was overwritten with
851 * the terminating null, and cphold points to the null.
852 * Then adjust the notion of available space in the buffer.
853 */
854 if (kdb_grepping_flag && !suspend_grep) {
855 *cphold = replaced_byte;
856 strcpy(kdb_buffer, cphold);
857 len = strlen(kdb_buffer);
858 next_avail = kdb_buffer + len;
859 size_avail = sizeof(kdb_buffer) - len;
860 }
861
862 kdb_print_out:
863 suspend_grep = 0; /* end of what may have been a recursive call */
864 if (logging)
865 console_loglevel = saved_loglevel;
866 /* kdb_printf_cpu locked the code above. */
867 smp_store_release(&kdb_printf_cpu, old_cpu);
868 local_irq_restore(flags);
869 return retlen;
870 }
871
kdb_printf(const char * fmt,...)872 int kdb_printf(const char *fmt, ...)
873 {
874 va_list ap;
875 int r;
876
877 va_start(ap, fmt);
878 r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap);
879 va_end(ap);
880
881 return r;
882 }
883 EXPORT_SYMBOL_GPL(kdb_printf);
884