readline/histfile.c

   1 /* histfile.c - functions to manipulate the history file. */
   2
   3 /* Copyright (C) 1989-2010 Free Software Foundation, Inc.
   4
   5    This file contains the GNU History Library (History), a set of
   6    routines for managing the text of previously typed lines.
   7
   8    History is free software: you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation, either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    History is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with History.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 /* The goal is to make the implementation transparent, so that you
  23    don't have to know what data types are used, just what functions
  24    you can call.  I think I have done that. */
  25
  26 #define READLINE_LIBRARY
  27
  28 #if defined (__TANDEM)
  29 #  include <floss.h>
  30 #endif
  31
  32 #if defined (HAVE_CONFIG_H)
  33 #  include <config.h>
  34 #endif
  35
  36 #include <stdio.h>
  37
  38 #include <sys/types.h>
  39 #if ! defined (_MINIX) && defined (HAVE_SYS_FILE_H)
  40 #  include <sys/file.h>
  41 #endif
  42 #include "posixstat.h"
  43 #include <fcntl.h>
  44
  45 #if defined (HAVE_STDLIB_H)
  46 #  include <stdlib.h>
  47 #else
  48 #  include "ansi_stdlib.h"
  49 #endif /* HAVE_STDLIB_H */
  50
  51 #if defined (HAVE_UNISTD_H)
  52 #  include <unistd.h>
  53 #endif
  54
  55 #include <ctype.h>
  56
  57 #if defined (__EMX__)
  58 #  undef HAVE_MMAP
  59 #endif
  60
  61 #ifdef HISTORY_USE_MMAP
  62 #  include <sys/mman.h>
  63
  64 #  ifdef MAP_FILE
  65 #    define MAP_RFLAGS  (MAP_FILE|MAP_PRIVATE)
  66 #    define MAP_WFLAGS  (MAP_FILE|MAP_SHARED)
  67 #  else
  68 #    define MAP_RFLAGS  MAP_PRIVATE
  69 #    define MAP_WFLAGS  MAP_SHARED
  70 #  endif
  71
  72 #  ifndef MAP_FAILED
  73 #    define MAP_FAILED  ((void *)-1)
  74 #  endif
  75
  76 #endif /* HISTORY_USE_MMAP */
  77
  78 /* If we're compiling for __EMX__ (OS/2) or __CYGWIN__ (cygwin32 environment
  79    on win 95/98/nt), we want to open files with O_BINARY mode so that there
  80    is no \n -> \r\n conversion performed.  On other systems, we don't want to
  81    mess around with O_BINARY at all, so we ensure that it's defined to 0. */
  82 #if defined (__EMX__) || defined (__CYGWIN__)
  83 #  ifndef O_BINARY
  84 #    define O_BINARY 0
  85 #  endif
  86 #else /* !__EMX__ && !__CYGWIN__ */
  87 #  undef O_BINARY
  88 #  define O_BINARY 0
  89 #endif /* !__EMX__ && !__CYGWIN__ */
  90
  91 #include <errno.h>
  92 #if !defined (errno)
  93 extern int errno;
  94 #endif /* !errno */
  95
  96 #include "history.h"
  97 #include "histlib.h"
  98
  99 #include "rlshell.h"
 100 #include "xmalloc.h"
 101
 102 /* If non-zero, we write timestamps to the history file in history_do_write() */
 103 int history_write_timestamps = 0;
 104
 105 /* Does S look like the beginning of a history timestamp entry?  Placeholder
 106    for more extensive tests. */
 107 #define HIST_TIMESTAMP_START(s)         (*(s) == history_comment_char && isdigit ((s)[1]) )
 108
 109 /* Return the string that should be used in the place of this
 110    filename.  This only matters when you don't specify the
 111    filename to read_history (), or write_history (). */
 112 static char *
 113 history_filename (filename)
 114      const char *filename;
 115 {
 116   char *return_val;
 117   const char *home;
 118   int home_len;
 119
 120   return_val = filename ? savestring (filename) : (char *)NULL;
 121
 122   if (return_val)
 123     return (return_val);
 124
 125   home = sh_get_env_value ("HOME");
 126
 127   if (home == 0)
 128     {
 129 #if 0
 130       home = ".";
 131       home_len = 1;
 132 #else
 133       return (NULL);
 134 #endif
 135     }
 136   else
 137     home_len = strlen (home);
 138
 139   return_val = (char *)xmalloc (2 + home_len + 8); /* strlen(".history") == 8 */
 140   strcpy (return_val, home);
 141   return_val[home_len] = '/';
 142 #if defined (__MSDOS__)
 143   strcpy (return_val + home_len + 1, "_history");
 144 #else
 145   strcpy (return_val + home_len + 1, ".history");
 146 #endif
 147
 148   return (return_val);
 149 }
 150
 151 /* Add the contents of FILENAME to the history list, a line at a time.
 152    If FILENAME is NULL, then read from ~/.history.  Returns 0 if
 153    successful, or errno if not. */
 154 int
 155 read_history (filename)
 156      const char *filename;
 157 {
 158   return (read_history_range (filename, 0, -1));
 159 }
 160
 161 /* Read a range of lines from FILENAME, adding them to the history list.
 162    Start reading at the FROM'th line and end at the TO'th.  If FROM
 163    is zero, start at the beginning.  If TO is less than FROM, read
 164    until the end of the file.  If FILENAME is NULL, then read from
 165    ~/.history.  Returns 0 if successful, or errno if not. */
 166 int
 167 read_history_range (filename, from, to)
 168      const char *filename;
 169      int from, to;
 170 {
 171   register char *line_start, *line_end, *p;
 172   char *input, *buffer, *bufend, *last_ts;
 173   int file, current_line, chars_read;
 174   struct stat finfo;
 175   size_t file_size;
 176 #if defined (EFBIG)
 177   int overflow_errno = EFBIG;
 178 #elif defined (EOVERFLOW)
 179   int overflow_errno = EOVERFLOW;
 180 #else
 181   int overflow_errno = EIO;
 182 #endif
 183
 184   buffer = last_ts = (char *)NULL;
 185   input = history_filename (filename);
 186   file = input ? open (input, O_RDONLY|O_BINARY, 0666) : -1;
 187
 188   if ((file < 0) || (fstat (file, &finfo) == -1))
 189     goto error_and_exit;
 190
 191   file_size = (size_t)finfo.st_size;
 192
 193   /* check for overflow on very large files */
 194   if (file_size != finfo.st_size || file_size + 1 < file_size)
 195     {
 196       errno = overflow_errno;
 197       goto error_and_exit;
 198     }
 199
 200 #ifdef HISTORY_USE_MMAP
 201   /* We map read/write and private so we can change newlines to NULs without
 202      affecting the underlying object. */
 203   buffer = (char *)mmap (0, file_size, PROT_READ|PROT_WRITE, MAP_RFLAGS, file, 0);
 204   if ((void *)buffer == MAP_FAILED)
 205     {
 206       errno = overflow_errno;
 207       goto error_and_exit;
 208     }
 209   chars_read = file_size;
 210 #else
 211   buffer = (char *)malloc (file_size + 1);
 212   if (buffer == 0)
 213     {
 214       errno = overflow_errno;
 215       goto error_and_exit;
 216     }
 217
 218   chars_read = read (file, buffer, file_size);
 219 #endif
 220   if (chars_read < 0)
 221     {
 222   error_and_exit:
 223       if (errno != 0)
 224         chars_read = errno;
 225       else
 226         chars_read = EIO;
 227       if (file >= 0)
 228         close (file);
 229
 230       FREE (input);
 231 #ifndef HISTORY_USE_MMAP
 232       FREE (buffer);
 233 #endif
 234
 235       return (chars_read);
 236     }
 237
 238   close (file);
 239
 240   /* Set TO to larger than end of file if negative. */
 241   if (to < 0)
 242     to = chars_read;
 243
 244   /* Start at beginning of file, work to end. */
 245   bufend = buffer + chars_read;
 246   current_line = 0;
 247
 248   /* Skip lines until we are at FROM. */
 249   for (line_start = line_end = buffer; line_end < bufend && current_line < from; line_end++)
 250     if (*line_end == '\n')
 251       {
 252         p = line_end + 1;
 253         /* If we see something we think is a timestamp, continue with this
 254            line.  We should check more extensively here... */
 255         if (HIST_TIMESTAMP_START(p) == 0)
 256           current_line++;
 257         line_start = p;
 258       }
 259
 260   /* If there are lines left to gobble, then gobble them now. */
 261   for (line_end = line_start; line_end < bufend; line_end++)
 262     if (*line_end == '\n')
 263       {
 264         /* Change to allow Windows-like \r\n end of line delimiter. */
 265         if (line_end > line_start && line_end[-1] == '\r')
 266           line_end[-1] = '\0';
 267         else
 268           *line_end = '\0';
 269
 270         if (*line_start)
 271           {
 272             if (HIST_TIMESTAMP_START(line_start) == 0)
 273               {
 274                 add_history (line_start);
 275                 if (last_ts)
 276                   {
 277                     add_history_time (last_ts);
 278                     last_ts = NULL;
 279                   }
 280               }
 281             else
 282               {
 283                 last_ts = line_start;
 284                 current_line--;
 285               }
 286           }
 287
 288         current_line++;
 289
 290         if (current_line >= to)
 291           break;
 292
 293         line_start = line_end + 1;
 294       }
 295
 296   FREE (input);
 297 #ifndef HISTORY_USE_MMAP
 298   FREE (buffer);
 299 #else
 300   munmap (buffer, file_size);
 301 #endif
 302
 303   return (0);
 304 }
 305
 306 /* Truncate the history file FNAME, leaving only LINES trailing lines.
 307    If FNAME is NULL, then use ~/.history.  Returns 0 on success, errno
 308    on failure. */
 309 int
 310 history_truncate_file (fname, lines)
 311      const char *fname;
 312      int lines;
 313 {
 314   char *buffer, *filename, *bp, *bp1;           /* bp1 == bp+1 */
 315   int file, chars_read, rv;
 316   struct stat finfo;
 317   size_t file_size;
 318
 319   buffer = (char *)NULL;
 320   filename = history_filename (fname);
 321   file = filename ? open (filename, O_RDONLY|O_BINARY, 0666) : -1;
 322   rv = 0;
 323
 324   /* Don't try to truncate non-regular files. */
 325   if (file == -1 || fstat (file, &finfo) == -1)
 326     {
 327       rv = errno;
 328       if (file != -1)
 329         close (file);
 330       goto truncate_exit;
 331     }
 332
 333   if (S_ISREG (finfo.st_mode) == 0)
 334     {
 335       close (file);
 336 #ifdef EFTYPE
 337       rv = EFTYPE;
 338 #else
 339       rv = EINVAL;
 340 #endif
 341       goto truncate_exit;
 342     }
 343
 344   file_size = (size_t)finfo.st_size;
 345
 346   /* check for overflow on very large files */
 347   if (file_size != finfo.st_size || file_size + 1 < file_size)
 348     {
 349       close (file);
 350 #if defined (EFBIG)
 351       rv = errno = EFBIG;
 352 #elif defined (EOVERFLOW)
 353       rv = errno = EOVERFLOW;
 354 #else
 355       rv = errno = EINVAL;
 356 #endif
 357       goto truncate_exit;
 358     }
 359
 360   buffer = (char *)malloc (file_size + 1);
 361   if (buffer == 0)
 362     {
 363       close (file);
 364       goto truncate_exit;
 365     }
 366
 367   chars_read = read (file, buffer, file_size);
 368   close (file);
 369
 370   if (chars_read <= 0)
 371     {
 372       rv = (chars_read < 0) ? errno : 0;
 373       goto truncate_exit;
 374     }
 375
 376   /* Count backwards from the end of buffer until we have passed
 377      LINES lines.  bp1 is set funny initially.  But since bp[1] can't
 378      be a comment character (since it's off the end) and *bp can't be
 379      both a newline and the history comment character, it should be OK. */
 380   for (bp1 = bp = buffer + chars_read - 1; lines && bp > buffer; bp--)
 381     {
 382       if (*bp == '\n' && HIST_TIMESTAMP_START(bp1) == 0)
 383         lines--;
 384       bp1 = bp;
 385     }
 386
 387   /* If this is the first line, then the file contains exactly the
 388      number of lines we want to truncate to, so we don't need to do
 389      anything.  It's the first line if we don't find a newline between
 390      the current value of i and 0.  Otherwise, write from the start of
 391      this line until the end of the buffer. */
 392   for ( ; bp > buffer; bp--)
 393     {
 394       if (*bp == '\n' && HIST_TIMESTAMP_START(bp1) == 0)
 395         {
 396           bp++;
 397           break;
 398         }
 399       bp1 = bp;
 400     }
 401
 402   /* Write only if there are more lines in the file than we want to
 403      truncate to. */
 404   if (bp > buffer && ((file = open (filename, O_WRONLY|O_TRUNC|O_BINARY, 0600)) != -1))
 405     {
 406       write (file, bp, chars_read - (bp - buffer));
 407
 408 #if defined (__BEOS__)
 409       /* BeOS ignores O_TRUNC. */
 410       ftruncate (file, chars_read - (bp - buffer));
 411 #endif
 412
 413       close (file);
 414     }
 415
 416  truncate_exit:
 417
 418   FREE (buffer);
 419
 420   xfree (filename);
 421   return rv;
 422 }
 423
 424 /* Workhorse function for writing history.  Writes NELEMENT entries
 425    from the history list to FILENAME.  OVERWRITE is non-zero if you
 426    wish to replace FILENAME with the entries. */
 427 static int
 428 history_do_write (filename, nelements, overwrite)
 429      const char *filename;
 430      int nelements, overwrite;
 431 {
 432   register int i;
 433   char *output;
 434   int file, mode, rv;
 435 #ifdef HISTORY_USE_MMAP
 436   size_t cursize;
 437
 438   mode = overwrite ? O_RDWR|O_CREAT|O_TRUNC|O_BINARY : O_RDWR|O_APPEND|O_BINARY;
 439 #else
 440   mode = overwrite ? O_WRONLY|O_CREAT|O_TRUNC|O_BINARY : O_WRONLY|O_APPEND|O_BINARY;
 441 #endif
 442   output = history_filename (filename);
 443   file = output ? open (output, mode, 0600) : -1;
 444   rv = 0;
 445
 446   if (file == -1)
 447     {
 448       FREE (output);
 449       return (errno);
 450     }
 451
 452 #ifdef HISTORY_USE_MMAP
 453   cursize = overwrite ? 0 : lseek (file, 0, SEEK_END);
 454 #endif
 455
 456   if (nelements > history_length)
 457     nelements = history_length;
 458
 459   /* Build a buffer of all the lines to write, and write them in one syscall.
 460      Suggested by Peter Ho (peter@robosts.oxford.ac.uk). */
 461   {
 462     HIST_ENTRY **the_history;   /* local */
 463     register int j;
 464     int buffer_size;
 465     char *buffer;
 466
 467     the_history = history_list ();
 468     /* Calculate the total number of bytes to write. */
 469     for (buffer_size = 0, i = history_length - nelements; i < history_length; i++)
 470 #if 0
 471       buffer_size += 2 + HISTENT_BYTES (the_history[i]);
 472 #else
 473       {
 474         if (history_write_timestamps && the_history[i]->timestamp && the_history[i]->timestamp[0])
 475           buffer_size += strlen (the_history[i]->timestamp) + 1;
 476         buffer_size += strlen (the_history[i]->line) + 1;
 477       }
 478 #endif
 479
 480     /* Allocate the buffer, and fill it. */
 481 #ifdef HISTORY_USE_MMAP
 482     if (ftruncate (file, buffer_size+cursize) == -1)
 483       goto mmap_error;
 484     buffer = (char *)mmap (0, buffer_size, PROT_READ|PROT_WRITE, MAP_WFLAGS, file, cursize);
 485     if ((void *)buffer == MAP_FAILED)
 486       {
 487 mmap_error:
 488         rv = errno;
 489         FREE (output);
 490         close (file);
 491         return rv;
 492       }
 493 #else
 494     buffer = (char *)malloc (buffer_size);
 495     if (buffer == 0)
 496       {
 497         rv = errno;
 498         FREE (output);
 499         close (file);
 500         return rv;
 501       }
 502 #endif
 503
 504     for (j = 0, i = history_length - nelements; i < history_length; i++)
 505       {
 506         if (history_write_timestamps && the_history[i]->timestamp && the_history[i]->timestamp[0])
 507           {
 508             strcpy (buffer + j, the_history[i]->timestamp);
 509             j += strlen (the_history[i]->timestamp);
 510             buffer[j++] = '\n';
 511           }
 512         strcpy (buffer + j, the_history[i]->line);
 513         j += strlen (the_history[i]->line);
 514         buffer[j++] = '\n';
 515       }
 516
 517 #ifdef HISTORY_USE_MMAP
 518     if (msync (buffer, buffer_size, 0) != 0 || munmap (buffer, buffer_size) != 0)
 519       rv = errno;
 520 #else
 521     if (write (file, buffer, buffer_size) < 0)
 522       rv = errno;
 523     xfree (buffer);
 524 #endif
 525   }
 526
 527   close (file);
 528
 529   FREE (output);
 530
 531   return (rv);
 532 }
 533
 534 /* Append NELEMENT entries to FILENAME.  The entries appended are from
 535    the end of the list minus NELEMENTs up to the end of the list. */
 536 int
 537 append_history (nelements, filename)
 538      int nelements;
 539      const char *filename;
 540 {
 541   return (history_do_write (filename, nelements, HISTORY_APPEND));
 542 }
 543
 544 /* Overwrite FILENAME with the current history.  If FILENAME is NULL,
 545    then write the history list to ~/.history.  Values returned
 546    are as in read_history ().*/
 547 int
 548 write_history (filename)
 549      const char *filename;
 550 {
 551   return (history_do_write (filename, history_length, HISTORY_OVERWRITE));
 552 }