readline/histfile.c

   1 /* histfile.c - functions to manipulate the history file. */
   2
   3 /* Copyright (C) 1989, 1992 Free Software Foundation, Inc.
   4
   5    This file contains the GNU History Library (the Library), a set of
   6    routines for managing the text of previously typed lines.
   7
   8    The Library 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 2, or (at your option)
  11    any later version.
  12
  13    The Library is distributed in the hope that it will be useful, but
  14    WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16    General Public License for more details.
  17
  18    The GNU General Public License is often shipped with GNU software, and
  19    is generally kept in a file called COPYING or LICENSE.  If you do not
  20    have a copy of the license, write to the Free Software Foundation,
  21    59 Temple Place, Suite 330, Boston, MA 02111 USA. */
  22
  23 /* The goal is to make the implementation transparent, so that you
  24    don't have to know what data types are used, just what functions
  25    you can call.  I think I have done that. */
  26 #define READLINE_LIBRARY
  27
  28 #if defined (HAVE_CONFIG_H)
  29 #  include <config.h>
  30 #endif
  31
  32 #include <stdio.h>
  33
  34 #include <sys/types.h>
  35 #ifndef _MINIX
  36 #  include <sys/file.h>
  37 #endif
  38 #include "posixstat.h"
  39 #include <fcntl.h>
  40
  41 #if defined (HAVE_STDLIB_H)
  42 #  include <stdlib.h>
  43 #else
  44 #  include "ansi_stdlib.h"
  45 #endif /* HAVE_STDLIB_H */
  46
  47 #if defined (HAVE_UNISTD_H)
  48 #  include <unistd.h>
  49 #endif
  50
  51 #if defined (__EMX__) || defined (__CYGWIN__)
  52 #  undef HAVE_MMAP
  53 #endif
  54
  55 #ifdef HAVE_MMAP
  56 #  include <sys/mman.h>
  57
  58 #  ifdef MAP_FILE
  59 #    define MAP_RFLAGS  (MAP_FILE|MAP_PRIVATE)
  60 #    define MAP_WFLAGS  (MAP_FILE|MAP_SHARED)
  61 #  else
  62 #    define MAP_RFLAGS  MAP_PRIVATE
  63 #    define MAP_WFLAGS  MAP_SHARED
  64 #  endif
  65
  66 #  ifndef MAP_FAILED
  67 #    define MAP_FAILED  ((void *)-1)
  68 #  endif
  69
  70 #endif /* HAVE_MMAP */
  71
  72 /* If we're compiling for __EMX__ (OS/2) or __CYGWIN__ (cygwin32 environment
  73    on win 95/98/nt), we want to open files with O_BINARY mode so that there
  74    is no \n -> \r\n conversion performed.  On other systems, we don't want to
  75    mess around with O_BINARY at all, so we ensure that it's defined to 0. */
  76 #if defined (__EMX__) || defined (__CYGWIN__)
  77 #  ifndef O_BINARY
  78 #    define O_BINARY 0
  79 #  endif
  80 #else /* !__EMX__ && !__CYGWIN__ */
  81 #  undef O_BINARY
  82 #  define O_BINARY 0
  83 #endif /* !__EMX__ && !__CYGWIN__ */
  84
  85 #include <errno.h>
  86 #if !defined (errno)
  87 extern int errno;
  88 #endif /* !errno */
  89
  90 #include "history.h"
  91 #include "histlib.h"
  92
  93 #include "rlshell.h"
  94 #include "xmalloc.h"
  95
  96 /* Return the string that should be used in the place of this
  97    filename.  This only matters when you don't specify the
  98    filename to read_history (), or write_history (). */
  99 static char *
 100 history_filename (filename)
 101      const char *filename;
 102 {
 103   char *return_val;
 104   const char *home;
 105   int home_len;
 106
 107   return_val = filename ? savestring (filename) : (char *)NULL;
 108
 109   if (return_val)
 110     return (return_val);
 111
 112   home = sh_get_env_value ("HOME");
 113
 114   if (home == 0)
 115     {
 116       home = ".";
 117       home_len = 1;
 118     }
 119   else
 120     home_len = strlen (home);
 121
 122   return_val = (char *)xmalloc (2 + home_len + 8); /* strlen(".history") == 8 */
 123   strcpy (return_val, home);
 124   return_val[home_len] = '/';
 125 #if defined (__MSDOS__)
 126   strcpy (return_val + home_len + 1, "_history");
 127 #else
 128   strcpy (return_val + home_len + 1, ".history");
 129 #endif
 130
 131   return (return_val);
 132 }
 133
 134 /* Add the contents of FILENAME to the history list, a line at a time.
 135    If FILENAME is NULL, then read from ~/.history.  Returns 0 if
 136    successful, or errno if not. */
 137 int
 138 read_history (filename)
 139      const char *filename;
 140 {
 141   return (read_history_range (filename, 0, -1));
 142 }
 143
 144 /* Read a range of lines from FILENAME, adding them to the history list.
 145    Start reading at the FROM'th line and end at the TO'th.  If FROM
 146    is zero, start at the beginning.  If TO is less than FROM, read
 147    until the end of the file.  If FILENAME is NULL, then read from
 148    ~/.history.  Returns 0 if successful, or errno if not. */
 149 int
 150 read_history_range (filename, from, to)
 151      const char *filename;
 152      int from, to;
 153 {
 154   register char *line_start, *line_end;
 155   char *input, *buffer, *bufend;
 156   int file, current_line, chars_read;
 157   struct stat finfo;
 158   size_t file_size;
 159
 160   buffer = (char *)NULL;
 161   input = history_filename (filename);
 162   file = open (input, O_RDONLY|O_BINARY, 0666);
 163
 164   if ((file < 0) || (fstat (file, &finfo) == -1))
 165     goto error_and_exit;
 166
 167   file_size = (size_t)finfo.st_size;
 168
 169   /* check for overflow on very large files */
 170   if (file_size != finfo.st_size || file_size + 1 < file_size)
 171     {
 172 #if defined (EFBIG)
 173       errno = EFBIG;
 174 #elif defined (EOVERFLOW)
 175       errno = EOVERFLOW;
 176 #endif
 177       goto error_and_exit;
 178     }
 179
 180 #ifdef HAVE_MMAP
 181   /* We map read/write and private so we can change newlines to NULs without
 182      affecting the underlying object. */
 183   buffer = (char *)mmap (0, file_size, PROT_READ|PROT_WRITE, MAP_RFLAGS, file, 0);
 184   if ((void *)buffer == MAP_FAILED)
 185     goto error_and_exit;
 186   chars_read = file_size;
 187 #else
 188   buffer = (char *)malloc (file_size + 1);
 189   if (buffer == 0)
 190     goto error_and_exit;
 191
 192   chars_read = read (file, buffer, file_size);
 193 #endif
 194   if (chars_read < 0)
 195     {
 196   error_and_exit:
 197       chars_read = errno;
 198       if (file >= 0)
 199         close (file);
 200
 201       FREE (input);
 202 #ifndef HAVE_MMAP
 203       FREE (buffer);
 204 #endif
 205
 206       return (chars_read);
 207     }
 208
 209   close (file);
 210
 211   /* Set TO to larger than end of file if negative. */
 212   if (to < 0)
 213     to = chars_read;
 214
 215   /* Start at beginning of file, work to end. */
 216   bufend = buffer + chars_read;
 217   current_line = 0;
 218
 219   /* Skip lines until we are at FROM. */
 220   for (line_start = line_end = buffer; line_end < bufend && current_line < from; line_end++)
 221     if (*line_end == '\n')
 222       {
 223         current_line++;
 224         line_start = line_end + 1;
 225       }
 226
 227   /* If there are lines left to gobble, then gobble them now. */
 228   for (line_end = line_start; line_end < bufend; line_end++)
 229     if (*line_end == '\n')
 230       {
 231         *line_end = '\0';
 232
 233         if (*line_start)
 234           add_history (line_start);
 235
 236         current_line++;
 237
 238         if (current_line >= to)
 239           break;
 240
 241         line_start = line_end + 1;
 242       }
 243
 244   FREE (input);
 245 #ifndef HAVE_MMAP
 246   FREE (buffer);
 247 #else
 248   munmap (buffer, file_size);
 249 #endif
 250
 251   return (0);
 252 }
 253
 254 /* Truncate the history file FNAME, leaving only LINES trailing lines.
 255    If FNAME is NULL, then use ~/.history.  Returns 0 on success, errno
 256    on failure. */
 257 int
 258 history_truncate_file (fname, lines)
 259      const char *fname;
 260      int lines;
 261 {
 262   char *buffer, *filename, *bp;
 263   int file, chars_read, rv;
 264   struct stat finfo;
 265   size_t file_size;
 266
 267   buffer = (char *)NULL;
 268   filename = history_filename (fname);
 269   file = open (filename, O_RDONLY|O_BINARY, 0666);
 270   rv = 0;
 271
 272   /* Don't try to truncate non-regular files. */
 273   if (file == -1 || fstat (file, &finfo) == -1)
 274     {
 275       rv = errno;
 276       if (file != -1)
 277         close (file);
 278       goto truncate_exit;
 279     }
 280
 281   if (S_ISREG (finfo.st_mode) == 0)
 282     {
 283       close (file);
 284 #ifdef EFTYPE
 285       rv = EFTYPE;
 286 #else
 287       rv = EINVAL;
 288 #endif
 289       goto truncate_exit;
 290     }
 291
 292   file_size = (size_t)finfo.st_size;
 293
 294   /* check for overflow on very large files */
 295   if (file_size != finfo.st_size || file_size + 1 < file_size)
 296     {
 297       close (file);
 298 #if defined (EFBIG)
 299       rv = errno = EFBIG;
 300 #elif defined (EOVERFLOW)
 301       rv = errno = EOVERFLOW;
 302 #else
 303       rv = errno = EINVAL;
 304 #endif
 305       goto truncate_exit;
 306     }
 307
 308   buffer = (char *)malloc (file_size + 1);
 309   if (buffer == 0)
 310     {
 311       close (file);
 312       goto truncate_exit;
 313     }
 314
 315   chars_read = read (file, buffer, file_size);
 316   close (file);
 317
 318   if (chars_read <= 0)
 319     {
 320       rv = (chars_read < 0) ? errno : 0;
 321       goto truncate_exit;
 322     }
 323
 324   /* Count backwards from the end of buffer until we have passed
 325      LINES lines. */
 326   for (bp = buffer + chars_read - 1; lines && bp > buffer; bp--)
 327     {
 328       if (*bp == '\n')
 329         lines--;
 330     }
 331
 332   /* If this is the first line, then the file contains exactly the
 333      number of lines we want to truncate to, so we don't need to do
 334      anything.  It's the first line if we don't find a newline between
 335      the current value of i and 0.  Otherwise, write from the start of
 336      this line until the end of the buffer. */
 337   for ( ; bp > buffer; bp--)
 338     if (*bp == '\n')
 339       {
 340         bp++;
 341         break;
 342       }
 343
 344   /* Write only if there are more lines in the file than we want to
 345      truncate to. */
 346   if (bp > buffer && ((file = open (filename, O_WRONLY|O_TRUNC|O_BINARY, 0600)) != -1))
 347     {
 348       write (file, bp, chars_read - (bp - buffer));
 349
 350 #if defined (__BEOS__)
 351       /* BeOS ignores O_TRUNC. */
 352       ftruncate (file, chars_read - (bp - buffer));
 353 #endif
 354
 355       close (file);
 356     }
 357
 358  truncate_exit:
 359
 360   FREE (buffer);
 361
 362   free (filename);
 363   return rv;
 364 }
 365
 366 /* Workhorse function for writing history.  Writes NELEMENT entries
 367    from the history list to FILENAME.  OVERWRITE is non-zero if you
 368    wish to replace FILENAME with the entries. */
 369 static int
 370 history_do_write (filename, nelements, overwrite)
 371      const char *filename;
 372      int nelements, overwrite;
 373 {
 374   register int i;
 375   char *output;
 376   int file, mode, rv;
 377   size_t cursize;
 378
 379 #ifdef HAVE_MMAP
 380   mode = overwrite ? O_RDWR|O_CREAT|O_TRUNC|O_BINARY : O_RDWR|O_APPEND|O_BINARY;
 381 #else
 382   mode = overwrite ? O_WRONLY|O_CREAT|O_TRUNC|O_BINARY : O_WRONLY|O_APPEND|O_BINARY;
 383 #endif
 384   output = history_filename (filename);
 385   rv = 0;
 386
 387   if ((file = open (output, mode, 0600)) == -1)
 388     {
 389       FREE (output);
 390       return (errno);
 391     }
 392
 393 #ifdef HAVE_MMAP
 394   cursize = overwrite ? 0 : lseek (file, 0, SEEK_END);
 395 #endif
 396
 397   if (nelements > history_length)
 398     nelements = history_length;
 399
 400   /* Build a buffer of all the lines to write, and write them in one syscall.
 401      Suggested by Peter Ho (peter@robosts.oxford.ac.uk). */
 402   {
 403     HIST_ENTRY **the_history;   /* local */
 404     register int j;
 405     int buffer_size;
 406     char *buffer;
 407
 408     the_history = history_list ();
 409     /* Calculate the total number of bytes to write. */
 410     for (buffer_size = 0, i = history_length - nelements; i < history_length; i++)
 411       buffer_size += 1 + strlen (the_history[i]->line);
 412
 413     /* Allocate the buffer, and fill it. */
 414 #ifdef HAVE_MMAP
 415     if (ftruncate (file, buffer_size+cursize) == -1)
 416       goto mmap_error;
 417     buffer = (char *)mmap (0, buffer_size, PROT_READ|PROT_WRITE, MAP_WFLAGS, file, cursize);
 418     if ((void *)buffer == MAP_FAILED)
 419       {
 420 mmap_error:
 421         rv = errno;
 422         FREE (output);
 423         close (file);
 424         return rv;
 425       }
 426 #else
 427     buffer = (char *)malloc (buffer_size);
 428     if (buffer == 0)
 429       {
 430         rv = errno;
 431         FREE (output);
 432         close (file);
 433         return rv;
 434       }
 435 #endif
 436
 437     for (j = 0, i = history_length - nelements; i < history_length; i++)
 438       {
 439         strcpy (buffer + j, the_history[i]->line);
 440         j += strlen (the_history[i]->line);
 441         buffer[j++] = '\n';
 442       }
 443
 444 #ifdef HAVE_MMAP
 445     if (msync (buffer, buffer_size, 0) != 0 || munmap (buffer, buffer_size) != 0)
 446       rv = errno;
 447 #else
 448     if (write (file, buffer, buffer_size) < 0)
 449       rv = errno;
 450     free (buffer);
 451 #endif
 452   }
 453
 454   close (file);
 455
 456   FREE (output);
 457
 458   return (rv);
 459 }
 460
 461 /* Append NELEMENT entries to FILENAME.  The entries appended are from
 462    the end of the list minus NELEMENTs up to the end of the list. */
 463 int
 464 append_history (nelements, filename)
 465      int nelements;
 466      const char *filename;
 467 {
 468   return (history_do_write (filename, nelements, HISTORY_APPEND));
 469 }
 470
 471 /* Overwrite FILENAME with the current history.  If FILENAME is NULL,
 472    then write the history list to ~/.history.  Values returned
 473    are as in read_history ().*/
 474 int
 475 write_history (filename)
 476      const char *filename;
 477 {
 478   return (history_do_write (filename, history_length, HISTORY_OVERWRITE));
 479 }