libiberty/argv.c

   1 /* Create and destroy argument vectors (argv's)
   2    Copyright (C) 1992, 2001, 2010 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 **@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 **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 **) malloc ((argc + 1) * sizeof (char *));
  76   if (copy == NULL)
  77     return NULL;
  78
  79   /* the strings */
  80   for (argc = 0; argv[argc] != NULL; argc++)
  81     {
  82       int len = strlen (argv[argc]);
  83       copy[argc] = (char *) malloc (len + 1);
  84       if (copy[argc] == NULL)
  85         {
  86           freeargv (copy);
  87           return NULL;
  88         }
  89       strcpy (copy[argc], argv[argc]);
  90     }
  91   copy[argc] = NULL;
  92   return copy;
  93 }
  94
  95 /*
  96
  97 @deftypefn Extension void freeargv (char **@var{vector})
  98
  99 Free an argument vector that was built using @code{buildargv}.  Simply
 100 scans through @var{vector}, freeing the memory for each argument until
 101 the terminating @code{NULL} is found, and then frees @var{vector}
 102 itself.
 103
 104 @end deftypefn
 105
 106 */
 107
 108 void freeargv (char **vector)
 109 {
 110   register char **scan;
 111
 112   if (vector != NULL)
 113     {
 114       for (scan = vector; *scan != NULL; scan++)
 115         {
 116           free (*scan);
 117         }
 118       free (vector);
 119     }
 120 }
 121
 122 static void
 123 consume_whitespace (const char **input)
 124 {
 125   while (ISSPACE (**input))
 126     {
 127       (*input)++;
 128     }
 129 }
 130
 131 static int
 132 only_whitespace (const char* input)
 133 {
 134   while (*input != EOS && ISSPACE (*input))
 135     input++;
 136
 137   return (*input == EOS);
 138 }
 139
 140 /*
 141
 142 @deftypefn Extension char** buildargv (char *@var{sp})
 143
 144 Given a pointer to a string, parse the string extracting fields
 145 separated by whitespace and optionally enclosed within either single
 146 or double quotes (which are stripped off), and build a vector of
 147 pointers to copies of the string for each field.  The input string
 148 remains unchanged.  The last element of the vector is followed by a
 149 @code{NULL} element.
 150
 151 All of the memory for the pointer array and copies of the string
 152 is obtained from @code{malloc}.  All of the memory can be returned to the
 153 system with the single function call @code{freeargv}, which takes the
 154 returned result of @code{buildargv}, as it's argument.
 155
 156 Returns a pointer to the argument vector if successful.  Returns
 157 @code{NULL} if @var{sp} is @code{NULL} or if there is insufficient
 158 memory to complete building the argument vector.
 159
 160 If the input is a null string (as opposed to a @code{NULL} pointer),
 161 then buildarg returns an argument vector that has one arg, a null
 162 string.
 163
 164 @end deftypefn
 165
 166 The memory for the argv array is dynamically expanded as necessary.
 167
 168 In order to provide a working buffer for extracting arguments into,
 169 with appropriate stripping of quotes and translation of backslash
 170 sequences, we allocate a working buffer at least as long as the input
 171 string.  This ensures that we always have enough space in which to
 172 work, since the extracted arg is never larger than the input string.
 173
 174 The argument vector is always kept terminated with a @code{NULL} arg
 175 pointer, so it can be passed to @code{freeargv} at any time, or
 176 returned, as appropriate.
 177
 178 */
 179
 180 char **buildargv (const char *input)
 181 {
 182   char *arg;
 183   char *copybuf;
 184   int squote = 0;
 185   int dquote = 0;
 186   int bsquote = 0;
 187   int argc = 0;
 188   int maxargc = 0;
 189   char **argv = NULL;
 190   char **nargv;
 191
 192   if (input != NULL)
 193     {
 194       copybuf = (char *) alloca (strlen (input) + 1);
 195       /* Is a do{}while to always execute the loop once.  Always return an
 196          argv, even for null strings.  See NOTES above, test case below. */
 197       do
 198         {
 199           /* Pick off argv[argc] */
 200           consume_whitespace (&input);
 201
 202           if ((maxargc == 0) || (argc >= (maxargc - 1)))
 203             {
 204               /* argv needs initialization, or expansion */
 205               if (argv == NULL)
 206                 {
 207                   maxargc = INITIAL_MAXARGC;
 208                   nargv = (char **) malloc (maxargc * sizeof (char *));
 209                 }
 210               else
 211                 {
 212                   maxargc *= 2;
 213                   nargv = (char **) realloc (argv, maxargc * sizeof (char *));
 214                 }
 215               if (nargv == NULL)
 216                 {
 217                   if (argv != NULL)
 218                     {
 219                       freeargv (argv);
 220                       argv = NULL;
 221                     }
 222                   break;
 223                 }
 224               argv = nargv;
 225               argv[argc] = NULL;
 226             }
 227           /* Begin scanning arg */
 228           arg = copybuf;
 229           while (*input != EOS)
 230             {
 231               if (ISSPACE (*input) && !squote && !dquote && !bsquote)
 232                 {
 233                   break;
 234                 }
 235               else
 236                 {
 237                   if (bsquote)
 238                     {
 239                       bsquote = 0;
 240                       *arg++ = *input;
 241                     }
 242                   else if (*input == '\\')
 243                     {
 244                       bsquote = 1;
 245                     }
 246                   else if (squote)
 247                     {
 248                       if (*input == '\'')
 249                         {
 250                           squote = 0;
 251                         }
 252                       else
 253                         {
 254                           *arg++ = *input;
 255                         }
 256                     }
 257                   else if (dquote)
 258                     {
 259                       if (*input == '"')
 260                         {
 261                           dquote = 0;
 262                         }
 263                       else
 264                         {
 265                           *arg++ = *input;
 266                         }
 267                     }
 268                   else
 269                     {
 270                       if (*input == '\'')
 271                         {
 272                           squote = 1;
 273                         }
 274                       else if (*input == '"')
 275                         {
 276                           dquote = 1;
 277                         }
 278                       else
 279                         {
 280                           *arg++ = *input;
 281                         }
 282                     }
 283                   input++;
 284                 }
 285             }
 286           *arg = EOS;
 287           argv[argc] = strdup (copybuf);
 288           if (argv[argc] == NULL)
 289             {
 290               freeargv (argv);
 291               argv = NULL;
 292               break;
 293             }
 294           argc++;
 295           argv[argc] = NULL;
 296
 297           consume_whitespace (&input);
 298         }
 299       while (*input != EOS);
 300     }
 301   return (argv);
 302 }
 303
 304 /*
 305
 306 @deftypefn Extension int writeargv (const char **@var{argv}, FILE *@var{file})
 307
 308 Write each member of ARGV, handling all necessary quoting, to the file
 309 named by FILE, separated by whitespace.  Return 0 on success, non-zero
 310 if an error occurred while writing to FILE.
 311
 312 @end deftypefn
 313
 314 */
 315
 316 int
 317 writeargv (char **argv, FILE *f)
 318 {
 319   int status = 0;
 320
 321   if (f == NULL)
 322     return 1;
 323
 324   while (*argv != NULL)
 325     {
 326       const char *arg = *argv;
 327
 328       while (*arg != EOS)
 329         {
 330           char c = *arg;
 331
 332           if (ISSPACE(c) || c == '\\' || c == '\'' || c == '"')
 333             if (EOF == fputc ('\\', f))
 334               {
 335                 status = 1;
 336                 goto done;
 337               }
 338
 339           if (EOF == fputc (c, f))
 340             {
 341               status = 1;
 342               goto done;
 343             }
 344           arg++;
 345         }
 346
 347       if (EOF == fputc ('\n', f))
 348         {
 349           status = 1;
 350           goto done;
 351         }
 352       argv++;
 353     }
 354
 355  done:
 356   return status;
 357 }
 358
 359 /*
 360
 361 @deftypefn Extension void expandargv (int *@var{argcp}, char ***@var{argvp})
 362
 363 The @var{argcp} and @code{argvp} arguments are pointers to the usual
 364 @code{argc} and @code{argv} arguments to @code{main}.  This function
 365 looks for arguments that begin with the character @samp{@@}.  Any such
 366 arguments are interpreted as ``response files''.  The contents of the
 367 response file are interpreted as additional command line options.  In
 368 particular, the file is separated into whitespace-separated strings;
 369 each such string is taken as a command-line option.  The new options
 370 are inserted in place of the option naming the response file, and
 371 @code{*argcp} and @code{*argvp} will be updated.  If the value of
 372 @code{*argvp} is modified by this function, then the new value has
 373 been dynamically allocated and can be deallocated by the caller with
 374 @code{freeargv}.  However, most callers will simply call
 375 @code{expandargv} near the beginning of @code{main} and allow the
 376 operating system to free the memory when the program exits.
 377
 378 @end deftypefn
 379
 380 */
 381
 382 void
 383 expandargv (int *argcp, char ***argvp)
 384 {
 385   /* The argument we are currently processing.  */
 386   int i = 0;
 387   /* Non-zero if ***argvp has been dynamically allocated.  */
 388   int argv_dynamic = 0;
 389   /* Limit the number of response files that we parse in order
 390      to prevent infinite recursion.  */
 391   unsigned int iteration_limit = 2000;
 392   /* Loop over the arguments, handling response files.  We always skip
 393      ARGVP[0], as that is the name of the program being run.  */
 394   while (++i < *argcp)
 395     {
 396       /* The name of the response file.  */
 397       const char *filename;
 398       /* The response file.  */
 399       FILE *f;
 400       /* An upper bound on the number of characters in the response
 401          file.  */
 402       long pos;
 403       /* The number of characters in the response file, when actually
 404          read.  */
 405       size_t len;
 406       /* A dynamically allocated buffer used to hold options read from a
 407          response file.  */
 408       char *buffer;
 409       /* Dynamically allocated storage for the options read from the
 410          response file.  */
 411       char **file_argv;
 412       /* The number of options read from the response file, if any.  */
 413       size_t file_argc;
 414       /* We are only interested in options of the form "@file".  */
 415       filename = (*argvp)[i];
 416       if (filename[0] != '@')
 417         continue;
 418       /* If we have iterated too many times then stop.  */
 419       if (-- iteration_limit == 0)
 420         {
 421           fprintf (stderr, "%s: error: too many @-files encountered\n", (*argvp)[0]);
 422           xexit (1);
 423         }
 424       /* Read the contents of the file.  */
 425       f = fopen (++filename, "r");
 426       if (!f)
 427         continue;
 428       if (fseek (f, 0L, SEEK_END) == -1)
 429         goto error;
 430       pos = ftell (f);
 431       if (pos == -1)
 432         goto error;
 433       if (fseek (f, 0L, SEEK_SET) == -1)
 434         goto error;
 435       buffer = (char *) xmalloc (pos * sizeof (char) + 1);
 436       len = fread (buffer, sizeof (char), pos, f);
 437       if (len != (size_t) pos
 438           /* On Windows, fread may return a value smaller than POS,
 439              due to CR/LF->CR translation when reading text files.
 440              That does not in-and-of itself indicate failure.  */
 441           && ferror (f))
 442         goto error;
 443       /* Add a NUL terminator.  */
 444       buffer[len] = '\0';
 445       /* If the file is empty or contains only whitespace, buildargv would
 446          return a single empty argument.  In this context we want no arguments,
 447          instead.  */
 448       if (only_whitespace (buffer))
 449         {
 450           file_argv = (char **) xmalloc (sizeof (char *));
 451           file_argv[0] = NULL;
 452         }
 453       else
 454         /* Parse the string.  */
 455         file_argv = buildargv (buffer);
 456       /* If *ARGVP is not already dynamically allocated, copy it.  */
 457       if (!argv_dynamic)
 458         {
 459           *argvp = dupargv (*argvp);
 460           if (!*argvp)
 461             {
 462               fputs ("\nout of memory\n", stderr);
 463               xexit (1);
 464             }
 465         }
 466       /* Count the number of arguments.  */
 467       file_argc = 0;
 468       while (file_argv[file_argc])
 469         ++file_argc;
 470       /* Now, insert FILE_ARGV into ARGV.  The "+1" below handles the
 471          NULL terminator at the end of ARGV.  */
 472       *argvp = ((char **)
 473                 xrealloc (*argvp,
 474                           (*argcp + file_argc + 1) * sizeof (char *)));
 475       memmove (*argvp + i + file_argc, *argvp + i + 1,
 476                (*argcp - i) * sizeof (char *));
 477       memcpy (*argvp + i, file_argv, file_argc * sizeof (char *));
 478       /* The original option has been replaced by all the new
 479          options.  */
 480       *argcp += file_argc - 1;
 481       /* Free up memory allocated to process the response file.  We do
 482          not use freeargv because the individual options in FILE_ARGV
 483          are now in the main ARGV.  */
 484       free (file_argv);
 485       free (buffer);
 486       /* Rescan all of the arguments just read to support response
 487          files that include other response files.  */
 488       --i;
 489     error:
 490       /* We're all done with the file now.  */
 491       fclose (f);
 492     }
 493 }
 494
 495 #ifdef MAIN
 496
 497 /* Simple little test driver. */
 498
 499 static const char *const tests[] =
 500 {
 501   "a simple command line",
 502   "arg 'foo' is single quoted",
 503   "arg \"bar\" is double quoted",
 504   "arg \"foo bar\" has embedded whitespace",
 505   "arg 'Jack said \\'hi\\'' has single quotes",
 506   "arg 'Jack said \\\"hi\\\"' has double quotes",
 507   "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",
 508
 509   /* This should be expanded into only one argument.  */
 510   "trailing-whitespace ",
 511
 512   "",
 513   NULL
 514 };
 515
 516 int
 517 main (void)
 518 {
 519   char **argv;
 520   const char *const *test;
 521   char **targs;
 522
 523   for (test = tests; *test != NULL; test++)
 524     {
 525       printf ("buildargv(\"%s\")\n", *test);
 526       if ((argv = buildargv (*test)) == NULL)
 527         {
 528           printf ("failed!\n\n");
 529         }
 530       else
 531         {
 532           for (targs = argv; *targs != NULL; targs++)
 533             {
 534               printf ("\t\"%s\"\n", *targs);
 535             }
 536           printf ("\n");
 537         }
 538       freeargv (argv);
 539     }
 540
 541   return 0;
 542 }
 543
 544 #endif  /* MAIN */