libiberty/argv.c

   1 /* Create and destroy argument vectors (argv's)
   2    Copyright (C) 1992, 2001, 2010, 2012 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
  39 #ifndef NULL
  40 #define NULL 0
  41 #endif
  42
  43 #ifndef EOS
  44 #define EOS '\0'
  45 #endif
  46
  47 #define INITIAL_MAXARGC 8       /* Number of args + NULL in initial argv */
  48
  49
  50 /*
  51
  52 @deftypefn Extension char** dupargv (char * const *@var{vector})
  53
  54 Duplicate an argument vector.  Simply scans through @var{vector},
  55 duplicating each argument until the terminating @code{NULL} is found.
  56 Returns a pointer to the argument vector if successful.  Returns
  57 @code{NULL} if there is insufficient memory to complete building the
  58 argument vector.
  59
  60 @end deftypefn
  61
  62 */
  63
  64 char **
  65 dupargv (char * const *argv)
  66 {
  67   int argc;
  68   char **copy;
  69
  70   if (argv == NULL)
  71     return NULL;
  72
  73   /* the vector */
  74   for (argc = 0; argv[argc] != NULL; argc++);
  75   copy = (char **) xmalloc ((argc + 1) * sizeof (char *));
  76
  77   /* the strings */
  78   for (argc = 0; argv[argc] != NULL; argc++)
  79     copy[argc] = xstrdup (argv[argc]);
  80   copy[argc] = NULL;
  81   return copy;
  82 }
  83
  84 /*
  85
  86 @deftypefn Extension void freeargv (char **@var{vector})
  87
  88 Free an argument vector that was built using @code{buildargv}.  Simply
  89 scans through @var{vector}, freeing the memory for each argument until
  90 the terminating @code{NULL} is found, and then frees @var{vector}
  91 itself.
  92
  93 @end deftypefn
  94
  95 */
  96
  97 void freeargv (char **vector)
  98 {
  99   register char **scan;
 100
 101   if (vector != NULL)
 102     {
 103       for (scan = vector; *scan != NULL; scan++)
 104         {
 105           free (*scan);
 106         }
 107       free (vector);
 108     }
 109 }
 110
 111 static void
 112 consume_whitespace (const char **input)
 113 {
 114   while (ISSPACE (**input))
 115     {
 116       (*input)++;
 117     }
 118 }
 119
 120 static int
 121 only_whitespace (const char* input)
 122 {
 123   while (*input != EOS && ISSPACE (*input))
 124     input++;
 125
 126   return (*input == EOS);
 127 }
 128
 129 /*
 130
 131 @deftypefn Extension char** buildargv (char *@var{sp})
 132
 133 Given a pointer to a string, parse the string extracting fields
 134 separated by whitespace and optionally enclosed within either single
 135 or double quotes (which are stripped off), and build a vector of
 136 pointers to copies of the string for each field.  The input string
 137 remains unchanged.  The last element of the vector is followed by a
 138 @code{NULL} element.
 139
 140 All of the memory for the pointer array and copies of the string
 141 is obtained from @code{xmalloc}.  All of the memory can be returned to the
 142 system with the single function call @code{freeargv}, which takes the
 143 returned result of @code{buildargv}, as it's argument.
 144
 145 Returns a pointer to the argument vector if successful.  Returns
 146 @code{NULL} if @var{sp} is @code{NULL} or if there is insufficient
 147 memory to complete building the argument vector.
 148
 149 If the input is a null string (as opposed to a @code{NULL} pointer),
 150 then buildarg returns an argument vector that has one arg, a null
 151 string.
 152
 153 @end deftypefn
 154
 155 The memory for the argv array is dynamically expanded as necessary.
 156
 157 In order to provide a working buffer for extracting arguments into,
 158 with appropriate stripping of quotes and translation of backslash
 159 sequences, we allocate a working buffer at least as long as the input
 160 string.  This ensures that we always have enough space in which to
 161 work, since the extracted arg is never larger than the input string.
 162
 163 The argument vector is always kept terminated with a @code{NULL} arg
 164 pointer, so it can be passed to @code{freeargv} at any time, or
 165 returned, as appropriate.
 166
 167 */
 168
 169 char **buildargv (const char *input)
 170 {
 171   char *arg;
 172   char *copybuf;
 173   int squote = 0;
 174   int dquote = 0;
 175   int bsquote = 0;
 176   int argc = 0;
 177   int maxargc = 0;
 178   char **argv = NULL;
 179   char **nargv;
 180
 181   if (input != NULL)
 182     {
 183       copybuf = (char *) xmalloc (strlen (input) + 1);
 184       /* Is a do{}while to always execute the loop once.  Always return an
 185          argv, even for null strings.  See NOTES above, test case below. */
 186       do
 187         {
 188           /* Pick off argv[argc] */
 189           consume_whitespace (&input);
 190
 191           if ((maxargc == 0) || (argc >= (maxargc - 1)))
 192             {
 193               /* argv needs initialization, or expansion */
 194               if (argv == NULL)
 195                 {
 196                   maxargc = INITIAL_MAXARGC;
 197                   nargv = (char **) xmalloc (maxargc * sizeof (char *));
 198                 }
 199               else
 200                 {
 201                   maxargc *= 2;
 202                   nargv = (char **) xrealloc (argv, maxargc * sizeof (char *));
 203                 }
 204               argv = nargv;
 205               argv[argc] = NULL;
 206             }
 207           /* Begin scanning arg */
 208           arg = copybuf;
 209           while (*input != EOS)
 210             {
 211               if (ISSPACE (*input) && !squote && !dquote && !bsquote)
 212                 {
 213                   break;
 214                 }
 215               else
 216                 {
 217                   if (bsquote)
 218                     {
 219                       bsquote = 0;
 220                       *arg++ = *input;
 221                     }
 222                   else if (*input == '\\')
 223                     {
 224                       bsquote = 1;
 225                     }
 226                   else if (squote)
 227                     {
 228                       if (*input == '\'')
 229                         {
 230                           squote = 0;
 231                         }
 232                       else
 233                         {
 234                           *arg++ = *input;
 235                         }
 236                     }
 237                   else if (dquote)
 238                     {
 239                       if (*input == '"')
 240                         {
 241                           dquote = 0;
 242                         }
 243                       else
 244                         {
 245                           *arg++ = *input;
 246                         }
 247                     }
 248                   else
 249                     {
 250                       if (*input == '\'')
 251                         {
 252                           squote = 1;
 253                         }
 254                       else if (*input == '"')
 255                         {
 256                           dquote = 1;
 257                         }
 258                       else
 259                         {
 260                           *arg++ = *input;
 261                         }
 262                     }
 263                   input++;
 264                 }
 265             }
 266           *arg = EOS;
 267           argv[argc] = xstrdup (copybuf);
 268           argc++;
 269           argv[argc] = NULL;
 270
 271           consume_whitespace (&input);
 272         }
 273       while (*input != EOS);
 274
 275       free (copybuf);
 276     }
 277   return (argv);
 278 }
 279
 280 /*
 281
 282 @deftypefn Extension int writeargv (char * const *@var{argv}, FILE *@var{file})
 283
 284 Write each member of ARGV, handling all necessary quoting, to the file
 285 named by FILE, separated by whitespace.  Return 0 on success, non-zero
 286 if an error occurred while writing to FILE.
 287
 288 @end deftypefn
 289
 290 */
 291
 292 int
 293 writeargv (char * const *argv, FILE *f)
 294 {
 295   int status = 0;
 296
 297   if (f == NULL)
 298     return 1;
 299
 300   while (*argv != NULL)
 301     {
 302       const char *arg = *argv;
 303
 304       while (*arg != EOS)
 305         {
 306           char c = *arg;
 307
 308           if (ISSPACE(c) || c == '\\' || c == '\'' || c == '"')
 309             if (EOF == fputc ('\\', f))
 310               {
 311                 status = 1;
 312                 goto done;
 313               }
 314
 315           if (EOF == fputc (c, f))
 316             {
 317               status = 1;
 318               goto done;
 319             }
 320           arg++;
 321         }
 322
 323       if (EOF == fputc ('\n', f))
 324         {
 325           status = 1;
 326           goto done;
 327         }
 328       argv++;
 329     }
 330
 331  done:
 332   return status;
 333 }
 334
 335 /*
 336
 337 @deftypefn Extension void expandargv (int *@var{argcp}, char ***@var{argvp})
 338
 339 The @var{argcp} and @code{argvp} arguments are pointers to the usual
 340 @code{argc} and @code{argv} arguments to @code{main}.  This function
 341 looks for arguments that begin with the character @samp{@@}.  Any such
 342 arguments are interpreted as ``response files''.  The contents of the
 343 response file are interpreted as additional command line options.  In
 344 particular, the file is separated into whitespace-separated strings;
 345 each such string is taken as a command-line option.  The new options
 346 are inserted in place of the option naming the response file, and
 347 @code{*argcp} and @code{*argvp} will be updated.  If the value of
 348 @code{*argvp} is modified by this function, then the new value has
 349 been dynamically allocated and can be deallocated by the caller with
 350 @code{freeargv}.  However, most callers will simply call
 351 @code{expandargv} near the beginning of @code{main} and allow the
 352 operating system to free the memory when the program exits.
 353
 354 @end deftypefn
 355
 356 */
 357
 358 void
 359 expandargv (int *argcp, char ***argvp)
 360 {
 361   /* The argument we are currently processing.  */
 362   int i = 0;
 363   /* Non-zero if ***argvp has been dynamically allocated.  */
 364   int argv_dynamic = 0;
 365   /* Limit the number of response files that we parse in order
 366      to prevent infinite recursion.  */
 367   unsigned int iteration_limit = 2000;
 368   /* Loop over the arguments, handling response files.  We always skip
 369      ARGVP[0], as that is the name of the program being run.  */
 370   while (++i < *argcp)
 371     {
 372       /* The name of the response file.  */
 373       const char *filename;
 374       /* The response file.  */
 375       FILE *f;
 376       /* An upper bound on the number of characters in the response
 377          file.  */
 378       long pos;
 379       /* The number of characters in the response file, when actually
 380          read.  */
 381       size_t len;
 382       /* A dynamically allocated buffer used to hold options read from a
 383          response file.  */
 384       char *buffer;
 385       /* Dynamically allocated storage for the options read from the
 386          response file.  */
 387       char **file_argv;
 388       /* The number of options read from the response file, if any.  */
 389       size_t file_argc;
 390       /* We are only interested in options of the form "@file".  */
 391       filename = (*argvp)[i];
 392       if (filename[0] != '@')
 393         continue;
 394       /* If we have iterated too many times then stop.  */
 395       if (-- iteration_limit == 0)
 396         {
 397           fprintf (stderr, "%s: error: too many @-files encountered\n", (*argvp)[0]);
 398           xexit (1);
 399         }
 400       /* Read the contents of the file.  */
 401       f = fopen (++filename, "r");
 402       if (!f)
 403         continue;
 404       if (fseek (f, 0L, SEEK_END) == -1)
 405         goto error;
 406       pos = ftell (f);
 407       if (pos == -1)
 408         goto error;
 409       if (fseek (f, 0L, SEEK_SET) == -1)
 410         goto error;
 411       buffer = (char *) xmalloc (pos * sizeof (char) + 1);
 412       len = fread (buffer, sizeof (char), pos, f);
 413       if (len != (size_t) pos
 414           /* On Windows, fread may return a value smaller than POS,
 415              due to CR/LF->CR translation when reading text files.
 416              That does not in-and-of itself indicate failure.  */
 417           && ferror (f))
 418         goto error;
 419       /* Add a NUL terminator.  */
 420       buffer[len] = '\0';
 421       /* If the file is empty or contains only whitespace, buildargv would
 422          return a single empty argument.  In this context we want no arguments,
 423          instead.  */
 424       if (only_whitespace (buffer))
 425         {
 426           file_argv = (char **) xmalloc (sizeof (char *));
 427           file_argv[0] = NULL;
 428         }
 429       else
 430         /* Parse the string.  */
 431         file_argv = buildargv (buffer);
 432       /* If *ARGVP is not already dynamically allocated, copy it.  */
 433       if (!argv_dynamic)
 434         *argvp = dupargv (*argvp);
 435       /* Count the number of arguments.  */
 436       file_argc = 0;
 437       while (file_argv[file_argc])
 438         ++file_argc;
 439       /* Now, insert FILE_ARGV into ARGV.  The "+1" below handles the
 440          NULL terminator at the end of ARGV.  */
 441       *argvp = ((char **)
 442                 xrealloc (*argvp,
 443                           (*argcp + file_argc + 1) * sizeof (char *)));
 444       memmove (*argvp + i + file_argc, *argvp + i + 1,
 445                (*argcp - i) * sizeof (char *));
 446       memcpy (*argvp + i, file_argv, file_argc * sizeof (char *));
 447       /* The original option has been replaced by all the new
 448          options.  */
 449       *argcp += file_argc - 1;
 450       /* Free up memory allocated to process the response file.  We do
 451          not use freeargv because the individual options in FILE_ARGV
 452          are now in the main ARGV.  */
 453       free (file_argv);
 454       free (buffer);
 455       /* Rescan all of the arguments just read to support response
 456          files that include other response files.  */
 457       --i;
 458     error:
 459       /* We're all done with the file now.  */
 460       fclose (f);
 461     }
 462 }
 463
 464 /*
 465
 466 @deftypefn Extension int countargv (char * const *@var{argv})
 467
 468 Return the number of elements in @var{argv}.
 469 Returns zero if @var{argv} is NULL.
 470
 471 @end deftypefn
 472
 473 */
 474
 475 int
 476 countargv (char * const *argv)
 477 {
 478   int argc;
 479
 480   if (argv == NULL)
 481     return 0;
 482   for (argc = 0; argv[argc] != NULL; argc++)
 483     continue;
 484   return argc;
 485 }
 486
 487 #ifdef MAIN
 488
 489 /* Simple little test driver. */
 490
 491 static const char *const tests[] =
 492 {
 493   "a simple command line",
 494   "arg 'foo' is single quoted",
 495   "arg \"bar\" is double quoted",
 496   "arg \"foo bar\" has embedded whitespace",
 497   "arg 'Jack said \\'hi\\'' has single quotes",
 498   "arg 'Jack said \\\"hi\\\"' has double quotes",
 499   "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",
 500
 501   /* This should be expanded into only one argument.  */
 502   "trailing-whitespace ",
 503
 504   "",
 505   NULL
 506 };
 507
 508 int
 509 main (void)
 510 {
 511   char **argv;
 512   const char *const *test;
 513   char **targs;
 514
 515   for (test = tests; *test != NULL; test++)
 516     {
 517       printf ("buildargv(\"%s\")\n", *test);
 518       if ((argv = buildargv (*test)) == NULL)
 519         {
 520           printf ("failed!\n\n");
 521         }
 522       else
 523         {
 524           for (targs = argv; *targs != NULL; targs++)
 525             {
 526               printf ("\t\"%s\"\n", *targs);
 527             }
 528           printf ("\n");
 529         }
 530       freeargv (argv);
 531     }
 532
 533   return 0;
 534 }
 535
 536 #endif  /* MAIN */