libiberty/argv.c

   1 /* Create and destroy argument vectors (argv's)
   2    Copyright (C) 1992-2023 Free Software Foundation, Inc.
   3    Written by Fred Fish @ Cygnus Support
   4
   5 This file is part of the libiberty library.
   6 Libiberty is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU Library General Public
   8 License as published by the Free Software Foundation; either
   9 version 2 of the License, or (at your option) any later version.
  10
  11 Libiberty is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 Library General Public License for more details.
  15
  16 You should have received a copy of the GNU Library General Public
  17 License along with libiberty; see the file COPYING.LIB.  If
  18 not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
  19 Boston, MA 02110-1301, USA.  */
  20
  21
  22 /*  Create and destroy argument vectors.  An argument vector is simply an
  23     array of string pointers, terminated by a NULL pointer. */
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28 #include "ansidecl.h"
  29 #include "libiberty.h"
  30 #include "safe-ctype.h"
  31
  32 /*  Routines imported from standard C runtime libraries. */
  33
  34 #include <stddef.h>
  35 #include <string.h>
  36 #include <stdlib.h>
  37 #include <stdio.h>
  38 #include <sys/types.h>
  39 #ifdef HAVE_UNISTD_H
  40 #include <unistd.h>
  41 #endif
  42 #if HAVE_SYS_STAT_H
  43 #include <sys/stat.h>
  44 #endif
  45
  46 #ifndef NULL
  47 #define NULL 0
  48 #endif
  49
  50 #ifndef EOS
  51 #define EOS '\0'
  52 #endif
  53
  54 #define INITIAL_MAXARGC 8       /* Number of args + NULL in initial argv */
  55
  56
  57 /*
  58
  59 @deftypefn Extension char** dupargv (char * const *@var{vector})
  60
  61 Duplicate an argument vector.  Simply scans through @var{vector},
  62 duplicating each argument until the terminating @code{NULL} is found.
  63 Returns a pointer to the argument vector if successful.  Returns
  64 @code{NULL} if there is insufficient memory to complete building the
  65 argument vector.
  66
  67 @end deftypefn
  68
  69 */
  70
  71 char **
  72 dupargv (char * const *argv)
  73 {
  74   int argc;
  75   char **copy;
  76
  77   if (argv == NULL)
  78     return NULL;
  79
  80   /* the vector */
  81   for (argc = 0; argv[argc] != NULL; argc++);
  82   copy = (char **) xmalloc ((argc + 1) * sizeof (char *));
  83
  84   /* the strings */
  85   for (argc = 0; argv[argc] != NULL; argc++)
  86     copy[argc] = xstrdup (argv[argc]);
  87   copy[argc] = NULL;
  88   return copy;
  89 }
  90
  91 /*
  92
  93 @deftypefn Extension void freeargv (char **@var{vector})
  94
  95 Free an argument vector that was built using @code{buildargv}.  Simply
  96 scans through @var{vector}, freeing the memory for each argument until
  97 the terminating @code{NULL} is found, and then frees @var{vector}
  98 itself.
  99
 100 @end deftypefn
 101
 102 */
 103
 104 void freeargv (char **vector)
 105 {
 106   register char **scan;
 107
 108   if (vector != NULL)
 109     {
 110       for (scan = vector; *scan != NULL; scan++)
 111         {
 112           free (*scan);
 113         }
 114       free (vector);
 115     }
 116 }
 117
 118 static void
 119 consume_whitespace (const char **input)
 120 {
 121   while (ISSPACE (**input))
 122     {
 123       (*input)++;
 124     }
 125 }
 126
 127 static int
 128 only_whitespace (const char* input)
 129 {
 130   while (*input != EOS && ISSPACE (*input))
 131     input++;
 132
 133   return (*input == EOS);
 134 }
 135
 136 /*
 137
 138 @deftypefn Extension char** buildargv (char *@var{sp})
 139
 140 Given a pointer to a string, parse the string extracting fields
 141 separated by whitespace and optionally enclosed within either single
 142 or double quotes (which are stripped off), and build a vector of
 143 pointers to copies of the string for each field.  The input string
 144 remains unchanged.  The last element of the vector is followed by a
 145 @code{NULL} element.
 146
 147 All of the memory for the pointer array and copies of the string
 148 is obtained from @code{xmalloc}.  All of the memory can be returned to the
 149 system with the single function call @code{freeargv}, which takes the
 150 returned result of @code{buildargv}, as it's argument.
 151
 152 Returns a pointer to the argument vector if successful.  Returns
 153 @code{NULL} if @var{sp} is @code{NULL} or if there is insufficient
 154 memory to complete building the argument vector.
 155
 156 If the input is a null string (as opposed to a @code{NULL} pointer),
 157 then buildarg returns an argument vector that has one arg, a null
 158 string.
 159
 160 @end deftypefn
 161
 162 The memory for the argv array is dynamically expanded as necessary.
 163
 164 In order to provide a working buffer for extracting arguments into,
 165 with appropriate stripping of quotes and translation of backslash
 166 sequences, we allocate a working buffer at least as long as the input
 167 string.  This ensures that we always have enough space in which to
 168 work, since the extracted arg is never larger than the input string.
 169
 170 The argument vector is always kept terminated with a @code{NULL} arg
 171 pointer, so it can be passed to @code{freeargv} at any time, or
 172 returned, as appropriate.
 173
 174 */
 175
 176 char **buildargv (const char *input)
 177 {
 178   char *arg;
 179   char *copybuf;
 180   int squote = 0;
 181   int dquote = 0;
 182   int bsquote = 0;
 183   int argc = 0;
 184   int maxargc = 0;
 185   char **argv = NULL;
 186   char **nargv;
 187
 188   if (input != NULL)
 189     {
 190       copybuf = (char *) xmalloc (strlen (input) + 1);
 191       /* Is a do{}while to always execute the loop once.  Always return an
 192          argv, even for null strings.  See NOTES above, test case below. */
 193       do
 194         {
 195           /* Pick off argv[argc] */
 196           consume_whitespace (&input);
 197
 198           if ((maxargc == 0) || (argc >= (maxargc - 1)))
 199             {
 200               /* argv needs initialization, or expansion */
 201               if (argv == NULL)
 202                 {
 203                   maxargc = INITIAL_MAXARGC;
 204                   nargv = (char **) xmalloc (maxargc * sizeof (char *));
 205                 }
 206               else
 207                 {
 208                   maxargc *= 2;
 209                   nargv = (char **) xrealloc (argv, maxargc * sizeof (char *));
 210                 }
 211               argv = nargv;
 212               argv[argc] = NULL;
 213             }
 214           /* Begin scanning arg */
 215           arg = copybuf;
 216           while (*input != EOS)
 217             {
 218               if (ISSPACE (*input) && !squote && !dquote && !bsquote)
 219                 {
 220                   break;
 221                 }
 222               else
 223                 {
 224                   if (bsquote)
 225                     {
 226                       bsquote = 0;
 227                       *arg++ = *input;
 228                     }
 229                   else if (*input == '\\')
 230                     {
 231                       bsquote = 1;
 232                     }
 233                   else if (squote)
 234                     {
 235                       if (*input == '\'')
 236                         {
 237                           squote = 0;
 238                         }
 239                       else
 240                         {
 241                           *arg++ = *input;
 242                         }
 243                     }
 244                   else if (dquote)
 245                     {
 246                       if (*input == '"')
 247                         {
 248                           dquote = 0;
 249                         }
 250                       else
 251                         {
 252                           *arg++ = *input;
 253                         }
 254                     }
 255                   else
 256                     {
 257                       if (*input == '\'')
 258                         {
 259                           squote = 1;
 260                         }
 261                       else if (*input == '"')
 262                         {
 263                           dquote = 1;
 264                         }
 265                       else
 266                         {
 267                           *arg++ = *input;
 268                         }
 269                     }
 270                   input++;
 271                 }
 272             }
 273           *arg = EOS;
 274           argv[argc] = xstrdup (copybuf);
 275           argc++;
 276           argv[argc] = NULL;
 277
 278           consume_whitespace (&input);
 279         }
 280       while (*input != EOS);
 281
 282       free (copybuf);
 283     }
 284   return (argv);
 285 }
 286
 287 /*
 288
 289 @deftypefn Extension int writeargv (char * const *@var{argv}, FILE *@var{file})
 290
 291 Write each member of ARGV, handling all necessary quoting, to the file
 292 associated with FILE, separated by whitespace.  Return 0 on success,
 293 non-zero if an error occurred while writing to FILE.
 294
 295 @end deftypefn
 296
 297 */
 298
 299 int
 300 writeargv (char * const *argv, FILE *f)
 301 {
 302   if (f == NULL)
 303     return 1;
 304
 305   while (*argv != NULL)
 306     {
 307       const char *arg = *argv;
 308
 309       while (*arg != EOS)
 310         {
 311           char c = *arg;
 312
 313           if (ISSPACE(c) || c == '\\' || c == '\'' || c == '"')
 314             if (EOF == fputc ('\\', f))
 315               return 1;
 316
 317           if (EOF == fputc (c, f))
 318             return 1;
 319
 320           arg++;
 321         }
 322
 323       /* Write out a pair of quotes for an empty argument.  */
 324       if (arg == *argv)
 325         if (EOF == fputs ("\"\"", f))
 326           return 1;
 327
 328       if (EOF == fputc ('\n', f))
 329         return 1;
 330
 331       argv++;
 332     }
 333
 334   return 0;
 335 }
 336
 337 /*
 338
 339 @deftypefn Extension void expandargv (int *@var{argcp}, char ***@var{argvp})
 340
 341 The @var{argcp} and @code{argvp} arguments are pointers to the usual
 342 @code{argc} and @code{argv} arguments to @code{main}.  This function
 343 looks for arguments that begin with the character @samp{@@}.  Any such
 344 arguments are interpreted as ``response files''.  The contents of the
 345 response file are interpreted as additional command line options.  In
 346 particular, the file is separated into whitespace-separated strings;
 347 each such string is taken as a command-line option.  The new options
 348 are inserted in place of the option naming the response file, and
 349 @code{*argcp} and @code{*argvp} will be updated.  If the value of
 350 @code{*argvp} is modified by this function, then the new value has
 351 been dynamically allocated and can be deallocated by the caller with
 352 @code{freeargv}.  However, most callers will simply call
 353 @code{expandargv} near the beginning of @code{main} and allow the
 354 operating system to free the memory when the program exits.
 355
 356 @end deftypefn
 357
 358 */
 359
 360 void
 361 expandargv (int *argcp, char ***argvp)
 362 {
 363   /* The argument we are currently processing.  */
 364   int i = 0;
 365   /* To check if ***argvp has been dynamically allocated.  */
 366   char ** const original_argv = *argvp;
 367   /* Limit the number of response files that we parse in order
 368      to prevent infinite recursion.  */
 369   unsigned int iteration_limit = 2000;
 370   /* Loop over the arguments, handling response files.  We always skip
 371      ARGVP[0], as that is the name of the program being run.  */
 372   while (++i < *argcp)
 373     {
 374       /* The name of the response file.  */
 375       const char *filename;
 376       /* The response file.  */
 377       FILE *f;
 378       /* An upper bound on the number of characters in the response
 379          file.  */
 380       long pos;
 381       /* The number of characters in the response file, when actually
 382          read.  */
 383       size_t len;
 384       /* A dynamically allocated buffer used to hold options read from a
 385          response file.  */
 386       char *buffer;
 387       /* Dynamically allocated storage for the options read from the
 388          response file.  */
 389       char **file_argv;
 390       /* The number of options read from the response file, if any.  */
 391       size_t file_argc;
 392 #ifdef S_ISDIR
 393       struct stat sb;
 394 #endif
 395       /* We are only interested in options of the form "@file".  */
 396       filename = (*argvp)[i];
 397       if (filename[0] != '@')
 398         continue;
 399       /* If we have iterated too many times then stop.  */
 400       if (-- iteration_limit == 0)
 401         {
 402           fprintf (stderr, "%s: error: too many @-files encountered\n", (*argvp)[0]);
 403           xexit (1);
 404         }
 405 #ifdef S_ISDIR
 406       if (stat (filename+1, &sb) < 0)
 407         continue;
 408       if (S_ISDIR(sb.st_mode))
 409         {
 410           fprintf (stderr, "%s: error: @-file refers to a directory\n", (*argvp)[0]);
 411           xexit (1);
 412         }
 413 #endif
 414       /* Read the contents of the file.  */
 415       f = fopen (++filename, "r");
 416       if (!f)
 417         continue;
 418       if (fseek (f, 0L, SEEK_END) == -1)
 419         goto error;
 420       pos = ftell (f);
 421       if (pos == -1)
 422         goto error;
 423       if (fseek (f, 0L, SEEK_SET) == -1)
 424         goto error;
 425       buffer = (char *) xmalloc (pos * sizeof (char) + 1);
 426       len = fread (buffer, sizeof (char), pos, f);
 427       if (len != (size_t) pos
 428           /* On Windows, fread may return a value smaller than POS,
 429              due to CR/LF->CR translation when reading text files.
 430              That does not in-and-of itself indicate failure.  */
 431           && ferror (f))
 432         {
 433           free (buffer);
 434           goto error;
 435         }
 436       /* Add a NUL terminator.  */
 437       buffer[len] = '\0';
 438       /* If the file is empty or contains only whitespace, buildargv would
 439          return a single empty argument.  In this context we want no arguments,
 440          instead.  */
 441       if (only_whitespace (buffer))
 442         {
 443           file_argv = (char **) xmalloc (sizeof (char *));
 444           file_argv[0] = NULL;
 445         }
 446       else
 447         /* Parse the string.  */
 448         file_argv = buildargv (buffer);
 449       /* If *ARGVP is not already dynamically allocated, copy it.  */
 450       if (*argvp == original_argv)
 451         *argvp = dupargv (*argvp);
 452       /* Count the number of arguments.  */
 453       file_argc = 0;
 454       while (file_argv[file_argc])
 455         ++file_argc;
 456       /* Free the original option's memory.  */
 457       free ((*argvp)[i]);
 458       /* Now, insert FILE_ARGV into ARGV.  The "+1" below handles the
 459          NULL terminator at the end of ARGV.  */
 460       *argvp = ((char **)
 461                 xrealloc (*argvp,
 462                           (*argcp + file_argc + 1) * sizeof (char *)));
 463       memmove (*argvp + i + file_argc, *argvp + i + 1,
 464                (*argcp - i) * sizeof (char *));
 465       memcpy (*argvp + i, file_argv, file_argc * sizeof (char *));
 466       /* The original option has been replaced by all the new
 467          options.  */
 468       *argcp += file_argc - 1;
 469       /* Free up memory allocated to process the response file.  We do
 470          not use freeargv because the individual options in FILE_ARGV
 471          are now in the main ARGV.  */
 472       free (file_argv);
 473       free (buffer);
 474       /* Rescan all of the arguments just read to support response
 475          files that include other response files.  */
 476       --i;
 477     error:
 478       /* We're all done with the file now.  */
 479       fclose (f);
 480     }
 481 }
 482
 483 /*
 484
 485 @deftypefn Extension int countargv (char * const *@var{argv})
 486
 487 Return the number of elements in @var{argv}.
 488 Returns zero if @var{argv} is NULL.
 489
 490 @end deftypefn
 491
 492 */
 493
 494 int
 495 countargv (char * const *argv)
 496 {
 497   int argc;
 498
 499   if (argv == NULL)
 500     return 0;
 501   for (argc = 0; argv[argc] != NULL; argc++)
 502     continue;
 503   return argc;
 504 }
 505
 506 #ifdef MAIN
 507
 508 /* Simple little test driver. */
 509
 510 static const char *const tests[] =
 511 {
 512   "a simple command line",
 513   "arg 'foo' is single quoted",
 514   "arg \"bar\" is double quoted",
 515   "arg \"foo bar\" has embedded whitespace",
 516   "arg 'Jack said \\'hi\\'' has single quotes",
 517   "arg 'Jack said \\\"hi\\\"' has double quotes",
 518   "a b c d e f g h i j k l m n o p q r s t u v w x y z 1 2 3 4 5 6 7 8 9",
 519
 520   /* This should be expanded into only one argument.  */
 521   "trailing-whitespace ",
 522
 523   "",
 524   NULL
 525 };
 526
 527 int
 528 main (void)
 529 {
 530   char **argv;
 531   const char *const *test;
 532   char **targs;
 533
 534   for (test = tests; *test != NULL; test++)
 535     {
 536       printf ("buildargv(\"%s\")\n", *test);
 537       if ((argv = buildargv (*test)) == NULL)
 538         {
 539           printf ("failed!\n\n");
 540         }
 541       else
 542         {
 543           for (targs = argv; *targs != NULL; targs++)
 544             {
 545               printf ("\t\"%s\"\n", *targs);
 546             }
 547           printf ("\n");
 548         }
 549       freeargv (argv);
 550     }
 551
 552   return 0;
 553 }
 554
 555 #endif  /* MAIN */