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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Kernel Debugger Architecture Independent Console I/O handler
4 *
5 * Copyright (c) 1999-2006 Silicon Graphics, Inc. All Rights Reserved.
6 * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
7 */
8
9#include <linux/types.h>
10#include <linux/ctype.h>
11#include <linux/kernel.h>
12#include <linux/init.h>
13#include <linux/kdev_t.h>
14#include <linux/console.h>
15#include <linux/string.h>
16#include <linux/sched.h>
17#include <linux/smp.h>
18#include <linux/nmi.h>
19#include <linux/delay.h>
20#include <linux/kgdb.h>
21#include <linux/kdb.h>
22#include <linux/kallsyms.h>
23#include "kdb_private.h"
24
25#define CMD_BUFLEN 256
26char kdb_prompt_str[CMD_BUFLEN];
27
28int kdb_trap_printk;
29int kdb_printf_cpu = -1;
30
31static int kgdb_transition_check(char *buffer)
32{
33 if (buffer[0] != '+' && buffer[0] != '$') {
34 KDB_STATE_SET(KGDB_TRANS);
35 kdb_printf("%s", buffer);
36 } else {
37 int slen = strlen(buffer);
38 if (slen > 3 && buffer[slen - 3] == '#') {
39 kdb_gdb_state_pass(buffer);
40 strcpy(buffer, "kgdb");
41 KDB_STATE_SET(DOING_KGDB);
42 return 1;
43 }
44 }
45 return 0;
46}
47
48/**
49 * kdb_handle_escape() - validity check on an accumulated escape sequence.
50 * @buf: Accumulated escape characters to be examined. Note that buf
51 * is not a string, it is an array of characters and need not be
52 * nil terminated.
53 * @sz: Number of accumulated escape characters.
54 *
55 * Return: -1 if the escape sequence is unwanted, 0 if it is incomplete,
56 * otherwise it returns a mapped key value to pass to the upper layers.
57 */
58static int kdb_handle_escape(char *buf, size_t sz)
59{
60 char *lastkey = buf + sz - 1;
61
62 switch (sz) {
63 case 1:
64 if (*lastkey == '\e')
65 return 0;
66 break;
67
68 case 2: /* \e<something> */
69 if (*lastkey == '[')
70 return 0;
71 break;
72
73 case 3:
74 switch (*lastkey) {
75 case 'A': /* \e[A, up arrow */
76 return 16;
77 case 'B': /* \e[B, down arrow */
78 return 14;
79 case 'C': /* \e[C, right arrow */
80 return 6;
81 case 'D': /* \e[D, left arrow */
82 return 2;
83 case '1': /* \e[<1,3,4>], may be home, del, end */
84 case '3':
85 case '4':
86 return 0;
87 }
88 break;
89
90 case 4:
91 if (*lastkey == '~') {
92 switch (buf[2]) {
93 case '1': /* \e[1~, home */
94 return 1;
95 case '3': /* \e[3~, del */
96 return 4;
97 case '4': /* \e[4~, end */
98 return 5;
99 }
100 }
101 break;
102 }
103
104 return -1;
105}
106
107/**
108 * kdb_getchar() - Read a single character from a kdb console (or consoles).
109 *
110 * Other than polling the various consoles that are currently enabled,
111 * most of the work done in this function is dealing with escape sequences.
112 *
113 * An escape key could be the start of a vt100 control sequence such as \e[D
114 * (left arrow) or it could be a character in its own right. The standard
115 * method for detecting the difference is to wait for 2 seconds to see if there
116 * are any other characters. kdb is complicated by the lack of a timer service
117 * (interrupts are off), by multiple input sources. Escape sequence processing
118 * has to be done as states in the polling loop.
119 *
120 * Return: The key pressed or a control code derived from an escape sequence.
121 */
122char kdb_getchar(void)
123{
124#define ESCAPE_UDELAY 1000
125#define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
126 char buf[4]; /* longest vt100 escape sequence is 4 bytes */
127 char *pbuf = buf;
128 int escape_delay = 0;
129 get_char_func *f, *f_prev = NULL;
130 int key;
131 static bool last_char_was_cr;
132
133 for (f = &kdb_poll_funcs[0]; ; ++f) {
134 if (*f == NULL) {
135 /* Reset NMI watchdog once per poll loop */
136 touch_nmi_watchdog();
137 f = &kdb_poll_funcs[0];
138 }
139
140 key = (*f)();
141 if (key == -1) {
142 if (escape_delay) {
143 udelay(ESCAPE_UDELAY);
144 if (--escape_delay == 0)
145 return '\e';
146 }
147 continue;
148 }
149
150 /*
151 * The caller expects that newlines are either CR or LF. However
152 * some terminals send _both_ CR and LF. Avoid having to handle
153 * this in the caller by stripping the LF if we saw a CR right
154 * before.
155 */
156 if (last_char_was_cr && key == '\n') {
157 last_char_was_cr = false;
158 continue;
159 }
160 last_char_was_cr = (key == '\r');
161
162 /*
163 * When the first character is received (or we get a change
164 * input source) we set ourselves up to handle an escape
165 * sequences (just in case).
166 */
167 if (f_prev != f) {
168 f_prev = f;
169 pbuf = buf;
170 escape_delay = ESCAPE_DELAY;
171 }
172
173 *pbuf++ = key;
174 key = kdb_handle_escape(buf, pbuf - buf);
175 if (key < 0) /* no escape sequence; return best character */
176 return buf[pbuf - buf == 2 ? 1 : 0];
177 if (key > 0)
178 return key;
179 }
180
181 unreachable();
182}
183
184/**
185 * kdb_position_cursor() - Place cursor in the correct horizontal position
186 * @prompt: Nil-terminated string containing the prompt string
187 * @buffer: Nil-terminated string containing the entire command line
188 * @cp: Cursor position, pointer the character in buffer where the cursor
189 * should be positioned.
190 *
191 * The cursor is positioned by sending a carriage-return and then printing
192 * the content of the line until we reach the correct cursor position.
193 *
194 * There is some additional fine detail here.
195 *
196 * Firstly, even though kdb_printf() will correctly format zero-width fields
197 * we want the second call to kdb_printf() to be conditional. That keeps things
198 * a little cleaner when LOGGING=1.
199 *
200 * Secondly, we can't combine everything into one call to kdb_printf() since
201 * that renders into a fixed length buffer and the combined print could result
202 * in unwanted truncation.
203 */
204static void kdb_position_cursor(char *prompt, char *buffer, char *cp)
205{
206 kdb_printf("\r%s", prompt);
207 if (cp > buffer)
208 kdb_printf("%.*s", (int)(cp - buffer), buffer);
209}
210
211/*
212 * kdb_read
213 *
214 * This function reads a string of characters, terminated by
215 * a newline, or by reaching the end of the supplied buffer,
216 * from the current kernel debugger console device.
217 * Parameters:
218 * buffer - Address of character buffer to receive input characters.
219 * bufsize - size, in bytes, of the character buffer
220 * Returns:
221 * Returns a pointer to the buffer containing the received
222 * character string. This string will be terminated by a
223 * newline character.
224 * Locking:
225 * No locks are required to be held upon entry to this
226 * function. It is not reentrant - it relies on the fact
227 * that while kdb is running on only one "master debug" cpu.
228 * Remarks:
229 * The buffer size must be >= 2.
230 */
231
232static char *kdb_read(char *buffer, size_t bufsize)
233{
234 char *cp = buffer;
235 char *bufend = buffer+bufsize-2; /* Reserve space for newline
236 * and null byte */
237 char *lastchar;
238 char *p_tmp;
239 char tmp;
240 static char tmpbuffer[CMD_BUFLEN];
241 int len = strlen(buffer);
242 int len_tmp;
243 int tab = 0;
244 int count;
245 int i;
246 int diag, dtab_count;
247 int key, ret;
248
249 diag = kdbgetintenv("DTABCOUNT", &dtab_count);
250 if (diag)
251 dtab_count = 30;
252
253 if (len > 0) {
254 cp += len;
255 if (*(buffer+len-1) == '\n')
256 cp--;
257 }
258
259 lastchar = cp;
260 *cp = '\0';
261 kdb_printf("%s", buffer);
262poll_again:
263 key = kdb_getchar();
264 if (key != 9)
265 tab = 0;
266 switch (key) {
267 case 8: /* backspace */
268 if (cp > buffer) {
269 memmove(cp-1, cp, lastchar - cp + 1);
270 lastchar--;
271 cp--;
272 kdb_printf("\b%s ", cp);
273 kdb_position_cursor(kdb_prompt_str, buffer, cp);
274 }
275 break;
276 case 10: /* linefeed */
277 case 13: /* carriage return */
278 *lastchar++ = '\n';
279 *lastchar++ = '\0';
280 if (!KDB_STATE(KGDB_TRANS)) {
281 KDB_STATE_SET(KGDB_TRANS);
282 kdb_printf("%s", buffer);
283 }
284 kdb_printf("\n");
285 return buffer;
286 case 4: /* Del */
287 if (cp < lastchar) {
288 memmove(cp, cp+1, lastchar - cp);
289 lastchar--;
290 kdb_printf("%s ", cp);
291 kdb_position_cursor(kdb_prompt_str, buffer, cp);
292 }
293 break;
294 case 1: /* Home */
295 if (cp > buffer) {
296 cp = buffer;
297 kdb_position_cursor(kdb_prompt_str, buffer, cp);
298 }
299 break;
300 case 5: /* End */
301 if (cp < lastchar) {
302 kdb_printf("%s", cp);
303 cp = lastchar;
304 }
305 break;
306 case 2: /* Left */
307 if (cp > buffer) {
308 kdb_printf("\b");
309 --cp;
310 }
311 break;
312 case 14: /* Down */
313 case 16: /* Up */
314 kdb_printf("\r%*c\r",
315 (int)(strlen(kdb_prompt_str) + (lastchar - buffer)),
316 ' ');
317 *lastchar = (char)key;
318 *(lastchar+1) = '\0';
319 return lastchar;
320 case 6: /* Right */
321 if (cp < lastchar) {
322 kdb_printf("%c", *cp);
323 ++cp;
324 }
325 break;
326 case 9: /* Tab */
327 if (tab < 2)
328 ++tab;
329
330 tmp = *cp;
331 *cp = '\0';
332 p_tmp = strrchr(buffer, ' ');
333 p_tmp = (p_tmp ? p_tmp + 1 : buffer);
334 strscpy(tmpbuffer, p_tmp);
335 *cp = tmp;
336
337 len = strlen(tmpbuffer);
338 count = kallsyms_symbol_complete(tmpbuffer, sizeof(tmpbuffer));
339 if (tab == 2 && count > 0) {
340 kdb_printf("\n%d symbols are found.", count);
341 if (count > dtab_count) {
342 count = dtab_count;
343 kdb_printf(" But only first %d symbols will"
344 " be printed.\nYou can change the"
345 " environment variable DTABCOUNT.",
346 count);
347 }
348 kdb_printf("\n");
349 for (i = 0; i < count; i++) {
350 ret = kallsyms_symbol_next(tmpbuffer, i, sizeof(tmpbuffer));
351 if (WARN_ON(!ret))
352 break;
353 if (ret != -E2BIG)
354 kdb_printf("%s ", tmpbuffer);
355 else
356 kdb_printf("%s... ", tmpbuffer);
357 tmpbuffer[len] = '\0';
358 }
359 if (i >= dtab_count)
360 kdb_printf("...");
361 kdb_printf("\n");
362 kdb_printf("%s", kdb_prompt_str);
363 kdb_printf("%s", buffer);
364 if (cp != lastchar)
365 kdb_position_cursor(kdb_prompt_str, buffer, cp);
366 } else if (tab != 2 && count > 0) {
367 /* How many new characters do we want from tmpbuffer? */
368 len_tmp = strlen(tmpbuffer) - len;
369 if (lastchar + len_tmp >= bufend)
370 len_tmp = bufend - lastchar;
371
372 if (len_tmp) {
373 /* + 1 ensures the '\0' is memmove'd */
374 memmove(cp+len_tmp, cp, (lastchar-cp) + 1);
375 memcpy(cp, tmpbuffer+len, len_tmp);
376 kdb_printf("%s", cp);
377 cp += len_tmp;
378 lastchar += len_tmp;
379 if (cp != lastchar)
380 kdb_position_cursor(kdb_prompt_str,
381 buffer, cp);
382 }
383 }
384 kdb_nextline = 1; /* reset output line number */
385 break;
386 default:
387 if (key >= 32 && lastchar < bufend) {
388 if (cp < lastchar) {
389 memmove(cp+1, cp, lastchar - cp + 1);
390 lastchar++;
391 *cp = key;
392 kdb_printf("%s", cp);
393 ++cp;
394 kdb_position_cursor(kdb_prompt_str, buffer, cp);
395 } else {
396 *++lastchar = '\0';
397 *cp++ = key;
398 /* The kgdb transition check will hide
399 * printed characters if we think that
400 * kgdb is connecting, until the check
401 * fails */
402 if (!KDB_STATE(KGDB_TRANS)) {
403 if (kgdb_transition_check(buffer))
404 return buffer;
405 } else {
406 kdb_printf("%c", key);
407 }
408 }
409 /* Special escape to kgdb */
410 if (lastchar - buffer >= 5 &&
411 strcmp(lastchar - 5, "$?#3f") == 0) {
412 kdb_gdb_state_pass(lastchar - 5);
413 strcpy(buffer, "kgdb");
414 KDB_STATE_SET(DOING_KGDB);
415 return buffer;
416 }
417 if (lastchar - buffer >= 11 &&
418 strcmp(lastchar - 11, "$qSupported") == 0) {
419 kdb_gdb_state_pass(lastchar - 11);
420 strcpy(buffer, "kgdb");
421 KDB_STATE_SET(DOING_KGDB);
422 return buffer;
423 }
424 }
425 break;
426 }
427 goto poll_again;
428}
429
430/*
431 * kdb_getstr
432 *
433 * Print the prompt string and read a command from the
434 * input device.
435 *
436 * Parameters:
437 * buffer Address of buffer to receive command
438 * bufsize Size of buffer in bytes
439 * prompt Pointer to string to use as prompt string
440 * Returns:
441 * Pointer to command buffer.
442 * Locking:
443 * None.
444 * Remarks:
445 * For SMP kernels, the processor number will be
446 * substituted for %d, %x or %o in the prompt.
447 */
448
449char *kdb_getstr(char *buffer, size_t bufsize, const char *prompt)
450{
451 if (prompt && kdb_prompt_str != prompt)
452 strscpy(kdb_prompt_str, prompt);
453 kdb_printf("%s", kdb_prompt_str);
454 kdb_nextline = 1; /* Prompt and input resets line number */
455 return kdb_read(buffer, bufsize);
456}
457
458/*
459 * kdb_input_flush
460 *
461 * Get rid of any buffered console input.
462 *
463 * Parameters:
464 * none
465 * Returns:
466 * nothing
467 * Locking:
468 * none
469 * Remarks:
470 * Call this function whenever you want to flush input. If there is any
471 * outstanding input, it ignores all characters until there has been no
472 * data for approximately 1ms.
473 */
474
475static void kdb_input_flush(void)
476{
477 get_char_func *f;
478 int res;
479 int flush_delay = 1;
480 while (flush_delay) {
481 flush_delay--;
482empty:
483 touch_nmi_watchdog();
484 for (f = &kdb_poll_funcs[0]; *f; ++f) {
485 res = (*f)();
486 if (res != -1) {
487 flush_delay = 1;
488 goto empty;
489 }
490 }
491 if (flush_delay)
492 mdelay(1);
493 }
494}
495
496/*
497 * kdb_printf
498 *
499 * Print a string to the output device(s).
500 *
501 * Parameters:
502 * printf-like format and optional args.
503 * Returns:
504 * 0
505 * Locking:
506 * None.
507 * Remarks:
508 * use 'kdbcons->write()' to avoid polluting 'log_buf' with
509 * kdb output.
510 *
511 * If the user is doing a cmd args | grep srch
512 * then kdb_grepping_flag is set.
513 * In that case we need to accumulate full lines (ending in \n) before
514 * searching for the pattern.
515 */
516
517static char kdb_buffer[256]; /* A bit too big to go on stack */
518static char *next_avail = kdb_buffer;
519static int size_avail;
520static int suspend_grep;
521
522/*
523 * search arg1 to see if it contains arg2
524 * (kdmain.c provides flags for ^pat and pat$)
525 *
526 * return 1 for found, 0 for not found
527 */
528static int kdb_search_string(char *searched, char *searchfor)
529{
530 char firstchar, *cp;
531 int len1, len2;
532
533 /* not counting the newline at the end of "searched" */
534 len1 = strlen(searched)-1;
535 len2 = strlen(searchfor);
536 if (len1 < len2)
537 return 0;
538 if (kdb_grep_leading && kdb_grep_trailing && len1 != len2)
539 return 0;
540 if (kdb_grep_leading) {
541 if (!strncmp(searched, searchfor, len2))
542 return 1;
543 } else if (kdb_grep_trailing) {
544 if (!strncmp(searched+len1-len2, searchfor, len2))
545 return 1;
546 } else {
547 firstchar = *searchfor;
548 cp = searched;
549 while ((cp = strchr(cp, firstchar))) {
550 if (!strncmp(cp, searchfor, len2))
551 return 1;
552 cp++;
553 }
554 }
555 return 0;
556}
557
558static void kdb_msg_write(const char *msg, int msg_len)
559{
560 struct console *c;
561 const char *cp;
562 int cookie;
563 int len;
564
565 if (msg_len == 0)
566 return;
567
568 cp = msg;
569 len = msg_len;
570
571 while (len--) {
572 dbg_io_ops->write_char(*cp);
573 cp++;
574 }
575
576 /*
577 * The console_srcu_read_lock() only provides safe console list
578 * traversal. The use of the ->write() callback relies on all other
579 * CPUs being stopped at the moment and console drivers being able to
580 * handle reentrance when @oops_in_progress is set.
581 *
582 * There is no guarantee that every console driver can handle
583 * reentrance in this way; the developer deploying the debugger
584 * is responsible for ensuring that the console drivers they
585 * have selected handle reentrance appropriately.
586 */
587 cookie = console_srcu_read_lock();
588 for_each_console_srcu(c) {
589 short flags = console_srcu_read_flags(c);
590
591 if (!console_is_usable(c, flags, true))
592 continue;
593 if (c == dbg_io_ops->cons)
594 continue;
595
596 if (flags & CON_NBCON) {
597 struct nbcon_write_context wctxt = { };
598
599 /*
600 * Do not continue if the console is NBCON and the context
601 * can't be acquired.
602 */
603 if (!nbcon_kdb_try_acquire(c, &wctxt))
604 continue;
605
606 nbcon_write_context_set_buf(&wctxt, (char *)msg, msg_len);
607
608 c->write_atomic(c, &wctxt);
609 nbcon_kdb_release(&wctxt);
610 } else {
611 /*
612 * Set oops_in_progress to encourage the console drivers to
613 * disregard their internal spin locks: in the current calling
614 * context the risk of deadlock is a bigger problem than risks
615 * due to re-entering the console driver. We operate directly on
616 * oops_in_progress rather than using bust_spinlocks() because
617 * the calls bust_spinlocks() makes on exit are not appropriate
618 * for this calling context.
619 */
620 ++oops_in_progress;
621 c->write(c, msg, msg_len);
622 --oops_in_progress;
623 }
624 touch_nmi_watchdog();
625 }
626 console_srcu_read_unlock(cookie);
627}
628
629int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
630{
631 int diag;
632 int linecount;
633 int colcount;
634 int logging, saved_loglevel = 0;
635 int retlen = 0;
636 int fnd, len;
637 int this_cpu, old_cpu;
638 char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
639 char *moreprompt = "more> ";
640 unsigned long flags;
641
642 /* Serialize kdb_printf if multiple cpus try to write at once.
643 * But if any cpu goes recursive in kdb, just print the output,
644 * even if it is interleaved with any other text.
645 */
646 local_irq_save(flags);
647 this_cpu = smp_processor_id();
648 for (;;) {
649 old_cpu = cmpxchg(&kdb_printf_cpu, -1, this_cpu);
650 if (old_cpu == -1 || old_cpu == this_cpu)
651 break;
652
653 cpu_relax();
654 }
655
656 diag = kdbgetintenv("LINES", &linecount);
657 if (diag || linecount <= 1)
658 linecount = 24;
659
660 diag = kdbgetintenv("COLUMNS", &colcount);
661 if (diag || colcount <= 1)
662 colcount = 80;
663
664 diag = kdbgetintenv("LOGGING", &logging);
665 if (diag)
666 logging = 0;
667
668 if (!kdb_grepping_flag || suspend_grep) {
669 /* normally, every vsnprintf starts a new buffer */
670 next_avail = kdb_buffer;
671 size_avail = sizeof(kdb_buffer);
672 }
673 vsnprintf(next_avail, size_avail, fmt, ap);
674
675 /*
676 * If kdb_parse() found that the command was cmd xxx | grep yyy
677 * then kdb_grepping_flag is set, and kdb_grep_string contains yyy
678 *
679 * Accumulate the print data up to a newline before searching it.
680 * (vsnprintf does null-terminate the string that it generates)
681 */
682
683 /* skip the search if prints are temporarily unconditional */
684 if (!suspend_grep && kdb_grepping_flag) {
685 cp = strchr(kdb_buffer, '\n');
686 if (!cp) {
687 /*
688 * Special cases that don't end with newlines
689 * but should be written without one:
690 * The "[nn]kdb> " prompt should
691 * appear at the front of the buffer.
692 *
693 * The "[nn]more " prompt should also be
694 * (MOREPROMPT -> moreprompt)
695 * written * but we print that ourselves,
696 * we set the suspend_grep flag to make
697 * it unconditional.
698 *
699 */
700 if (next_avail == kdb_buffer) {
701 /*
702 * these should occur after a newline,
703 * so they will be at the front of the
704 * buffer
705 */
706 cp2 = kdb_buffer;
707 len = strlen(kdb_prompt_str);
708 if (!strncmp(cp2, kdb_prompt_str, len)) {
709 /*
710 * We're about to start a new
711 * command, so we can go back
712 * to normal mode.
713 */
714 kdb_grepping_flag = 0;
715 goto kdb_printit;
716 }
717 }
718 /* no newline; don't search/write the buffer
719 until one is there */
720 len = strlen(kdb_buffer);
721 next_avail = kdb_buffer + len;
722 size_avail = sizeof(kdb_buffer) - len;
723 goto kdb_print_out;
724 }
725
726 /*
727 * The newline is present; print through it or discard
728 * it, depending on the results of the search.
729 */
730 cp++; /* to byte after the newline */
731 replaced_byte = *cp; /* remember what it was */
732 cphold = cp; /* remember where it was */
733 *cp = '\0'; /* end the string for our search */
734
735 /*
736 * We now have a newline at the end of the string
737 * Only continue with this output if it contains the
738 * search string.
739 */
740 fnd = kdb_search_string(kdb_buffer, kdb_grep_string);
741 if (!fnd) {
742 /*
743 * At this point the complete line at the start
744 * of kdb_buffer can be discarded, as it does
745 * not contain what the user is looking for.
746 * Shift the buffer left.
747 */
748 *cphold = replaced_byte;
749 len = strlen(cphold);
750 /* Use memmove() because the buffers overlap */
751 memmove(kdb_buffer, cphold, len + 1);
752 next_avail = kdb_buffer + len;
753 size_avail = sizeof(kdb_buffer) - len;
754 goto kdb_print_out;
755 }
756 if (kdb_grepping_flag >= KDB_GREPPING_FLAG_SEARCH) {
757 /*
758 * This was a interactive search (using '/' at more
759 * prompt) and it has completed. Replace the \0 with
760 * its original value to ensure multi-line strings
761 * are handled properly, and return to normal mode.
762 */
763 *cphold = replaced_byte;
764 kdb_grepping_flag = 0;
765 }
766 /*
767 * at this point the string is a full line and
768 * should be printed, up to the null.
769 */
770 }
771kdb_printit:
772
773 /*
774 * Write to all consoles.
775 */
776 retlen = strlen(kdb_buffer);
777 cp = (char *) printk_skip_headers(kdb_buffer);
778 if (!dbg_kdb_mode && kgdb_connected)
779 gdbstub_msg_write(cp, retlen - (cp - kdb_buffer));
780 else
781 kdb_msg_write(cp, retlen - (cp - kdb_buffer));
782
783 if (logging) {
784 saved_loglevel = console_loglevel;
785 console_loglevel = CONSOLE_LOGLEVEL_SILENT;
786 if (printk_get_level(kdb_buffer) || src == KDB_MSGSRC_PRINTK)
787 printk("%s", kdb_buffer);
788 else
789 pr_info("%s", kdb_buffer);
790 }
791
792 if (KDB_STATE(PAGER)) {
793 /*
794 * Check printed string to decide how to bump the
795 * kdb_nextline to control when the more prompt should
796 * show up.
797 */
798 int got = 0;
799 len = retlen;
800 while (len--) {
801 if (kdb_buffer[len] == '\n') {
802 kdb_nextline++;
803 got = 0;
804 } else if (kdb_buffer[len] == '\r') {
805 got = 0;
806 } else {
807 got++;
808 }
809 }
810 kdb_nextline += got / (colcount + 1);
811 }
812
813 /* check for having reached the LINES number of printed lines */
814 if (kdb_nextline >= linecount) {
815 char ch;
816
817 /* Watch out for recursion here. Any routine that calls
818 * kdb_printf will come back through here. And kdb_read
819 * uses kdb_printf to echo on serial consoles ...
820 */
821 kdb_nextline = 1; /* In case of recursion */
822
823 /*
824 * Pause until cr.
825 */
826 moreprompt = kdbgetenv("MOREPROMPT");
827 if (moreprompt == NULL)
828 moreprompt = "more> ";
829
830 kdb_input_flush();
831 kdb_msg_write(moreprompt, strlen(moreprompt));
832
833 if (logging)
834 printk("%s", moreprompt);
835
836 ch = kdb_getchar();
837 kdb_nextline = 1; /* Really set output line 1 */
838
839 /* empty and reset the buffer: */
840 kdb_buffer[0] = '\0';
841 next_avail = kdb_buffer;
842 size_avail = sizeof(kdb_buffer);
843 if ((ch == 'q') || (ch == 'Q')) {
844 /* user hit q or Q */
845 KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */
846 KDB_STATE_CLEAR(PAGER);
847 /* end of command output; back to normal mode */
848 kdb_grepping_flag = 0;
849 kdb_printf("\n");
850 } else if (ch == ' ') {
851 kdb_printf("\r");
852 suspend_grep = 1; /* for this recursion */
853 } else if (ch == '\n' || ch == '\r') {
854 kdb_nextline = linecount - 1;
855 kdb_printf("\r");
856 suspend_grep = 1; /* for this recursion */
857 } else if (ch == '/' && !kdb_grepping_flag) {
858 kdb_printf("\r");
859 kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
860 kdbgetenv("SEARCHPROMPT") ?: "search> ");
861 *strchrnul(kdb_grep_string, '\n') = '\0';
862 kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
863 suspend_grep = 1; /* for this recursion */
864 } else if (ch) {
865 /* user hit something unexpected */
866 suspend_grep = 1; /* for this recursion */
867 if (ch != '/')
868 kdb_printf(
869 "\nOnly 'q', 'Q' or '/' are processed at "
870 "more prompt, input ignored\n");
871 else
872 kdb_printf("\n'/' cannot be used during | "
873 "grep filtering, input ignored\n");
874 } else if (kdb_grepping_flag) {
875 /* user hit enter */
876 suspend_grep = 1; /* for this recursion */
877 kdb_printf("\n");
878 }
879 kdb_input_flush();
880 }
881
882 /*
883 * For grep searches, shift the printed string left.
884 * replaced_byte contains the character that was overwritten with
885 * the terminating null, and cphold points to the null.
886 * Then adjust the notion of available space in the buffer.
887 */
888 if (kdb_grepping_flag && !suspend_grep) {
889 *cphold = replaced_byte;
890 len = strlen(cphold);
891 /* Use memmove() because the buffers overlap */
892 memmove(kdb_buffer, cphold, len + 1);
893 next_avail = kdb_buffer + len;
894 size_avail = sizeof(kdb_buffer) - len;
895 }
896
897kdb_print_out:
898 suspend_grep = 0; /* end of what may have been a recursive call */
899 if (logging)
900 console_loglevel = saved_loglevel;
901 /* kdb_printf_cpu locked the code above. */
902 smp_store_release(&kdb_printf_cpu, old_cpu);
903 local_irq_restore(flags);
904 return retlen;
905}
906
907int kdb_printf(const char *fmt, ...)
908{
909 va_list ap;
910 int r;
911
912 va_start(ap, fmt);
913 r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap);
914 va_end(ap);
915
916 return r;
917}
918EXPORT_SYMBOL_GPL(kdb_printf);