kernel/debug/kdb/kdb_io.c

   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);