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