src/pathchk.c

   1 /* pathchk -- check whether file names are valid or portable
   2    Copyright (C) 1991-2013 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18 #include <stdio.h>
  19 #include <getopt.h>
  20 #include <sys/types.h>
  21 #include <wchar.h>
  22
  23 #include "system.h"
  24 #include "error.h"
  25 #include "quote.h"
  26 #include "quotearg.h"
  27
  28 /* The official name of this program (e.g., no 'g' prefix).  */
  29 #define PROGRAM_NAME "pathchk"
  30
  31 #define AUTHORS \
  32   proper_name ("Paul Eggert"), \
  33   proper_name ("David MacKenzie"), \
  34   proper_name ("Jim Meyering")
  35
  36 #ifndef _POSIX_PATH_MAX
  37 # define _POSIX_PATH_MAX 256
  38 #endif
  39 #ifndef _POSIX_NAME_MAX
  40 # define _POSIX_NAME_MAX 14
  41 #endif
  42
  43 #ifdef _XOPEN_NAME_MAX
  44 # define NAME_MAX_MINIMUM _XOPEN_NAME_MAX
  45 #else
  46 # define NAME_MAX_MINIMUM _POSIX_NAME_MAX
  47 #endif
  48 #ifdef _XOPEN_PATH_MAX
  49 # define PATH_MAX_MINIMUM _XOPEN_PATH_MAX
  50 #else
  51 # define PATH_MAX_MINIMUM _POSIX_PATH_MAX
  52 #endif
  53
  54 #if ! (HAVE_PATHCONF && defined _PC_NAME_MAX && defined _PC_PATH_MAX)
  55 # ifndef _PC_NAME_MAX
  56 #  define _PC_NAME_MAX 0
  57 #  define _PC_PATH_MAX 1
  58 # endif
  59 # ifndef pathconf
  60 #  define pathconf(file, flag) \
  61      (flag == _PC_NAME_MAX ? NAME_MAX_MINIMUM : PATH_MAX_MINIMUM)
  62 # endif
  63 #endif
  64
  65 static bool validate_file_name (char *, bool, bool);
  66
  67 /* For long options that have no equivalent short option, use a
  68    non-character as a pseudo short option, starting with CHAR_MAX + 1.  */
  69 enum
  70 {
  71   PORTABILITY_OPTION = CHAR_MAX + 1
  72 };
  73
  74 static struct option const longopts[] =
  75 {
  76   {"portability", no_argument, NULL, PORTABILITY_OPTION},
  77   {GETOPT_HELP_OPTION_DECL},
  78   {GETOPT_VERSION_OPTION_DECL},
  79   {NULL, 0, NULL, 0}
  80 };
  81
  82 void
  83 usage (int status)
  84 {
  85   if (status != EXIT_SUCCESS)
  86     emit_try_help ();
  87   else
  88     {
  89       printf (_("Usage: %s [OPTION]... NAME...\n"), program_name);
  90       fputs (_("\
  91 Diagnose invalid or unportable file names.\n\
  92 \n\
  93   -p                  check for most POSIX systems\n\
  94   -P                  check for empty names and leading \"-\"\n\
  95       --portability   check for all POSIX systems (equivalent to -p -P)\n\
  96 "), stdout);
  97       fputs (HELP_OPTION_DESCRIPTION, stdout);
  98       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  99       emit_ancillary_info ();
 100     }
 101   exit (status);
 102 }
 103
 104 int
 105 main (int argc, char **argv)
 106 {
 107   bool ok = true;
 108   bool check_basic_portability = false;
 109   bool check_extra_portability = false;
 110   int optc;
 111
 112   initialize_main (&argc, &argv);
 113   set_program_name (argv[0]);
 114   setlocale (LC_ALL, "");
 115   bindtextdomain (PACKAGE, LOCALEDIR);
 116   textdomain (PACKAGE);
 117
 118   atexit (close_stdout);
 119
 120   while ((optc = getopt_long (argc, argv, "+pP", longopts, NULL)) != -1)
 121     {
 122       switch (optc)
 123         {
 124         case PORTABILITY_OPTION:
 125           check_basic_portability = true;
 126           check_extra_portability = true;
 127           break;
 128
 129         case 'p':
 130           check_basic_portability = true;
 131           break;
 132
 133         case 'P':
 134           check_extra_portability = true;
 135           break;
 136
 137         case_GETOPT_HELP_CHAR;
 138
 139         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 140
 141         default:
 142           usage (EXIT_FAILURE);
 143         }
 144     }
 145
 146   if (optind == argc)
 147     {
 148       error (0, 0, _("missing operand"));
 149       usage (EXIT_FAILURE);
 150     }
 151
 152   for (; optind < argc; ++optind)
 153     ok &= validate_file_name (argv[optind],
 154                               check_basic_portability, check_extra_portability);
 155
 156   exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 157 }
 158
 159 /* If FILE contains a component with a leading "-", report an error
 160    and return false; otherwise, return true.  */
 161
 162 static bool
 163 no_leading_hyphen (char const *file)
 164 {
 165   char const *p;
 166
 167   for (p = file;  (p = strchr (p, '-'));  p++)
 168     if (p == file || p[-1] == '/')
 169       {
 170         error (0, 0, _("leading '-' in a component of file name %s"),
 171                quote (file));
 172         return false;
 173       }
 174
 175   return true;
 176 }
 177
 178 /* If FILE (of length FILELEN) contains only portable characters,
 179    return true, else report an error and return false.  */
 180
 181 static bool
 182 portable_chars_only (char const *file, size_t filelen)
 183 {
 184   size_t validlen = strspn (file,
 185                             ("/"
 186                              "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 187                              "abcdefghijklmnopqrstuvwxyz"
 188                              "0123456789._-"));
 189   char const *invalid = file + validlen;
 190
 191   if (*invalid)
 192     {
 193       mbstate_t mbstate = { 0, };
 194       size_t charlen = mbrlen (invalid, filelen - validlen, &mbstate);
 195       error (0, 0,
 196              _("nonportable character %s in file name %s"),
 197              quotearg_n_style_mem (1, locale_quoting_style, invalid,
 198                                    (charlen <= MB_LEN_MAX ? charlen : 1)),
 199              quote_n (0, file));
 200       return false;
 201     }
 202
 203   return true;
 204 }
 205
 206 /* Return the address of the start of the next file name component in F.  */
 207
 208 static char * _GL_ATTRIBUTE_PURE
 209 component_start (char *f)
 210 {
 211   while (*f == '/')
 212     f++;
 213   return f;
 214 }
 215
 216 /* Return the size of the file name component F.  F must be nonempty.  */
 217
 218 static size_t _GL_ATTRIBUTE_PURE
 219 component_len (char const *f)
 220 {
 221   size_t len;
 222   for (len = 1; f[len] != '/' && f[len]; len++)
 223     continue;
 224   return len;
 225 }
 226
 227 /* Make sure that
 228    strlen (FILE) <= PATH_MAX
 229    && strlen (each-existing-directory-in-FILE) <= NAME_MAX
 230
 231    If CHECK_BASIC_PORTABILITY is true, compare against _POSIX_PATH_MAX and
 232    _POSIX_NAME_MAX instead, and make sure that FILE contains no
 233    characters not in the POSIX portable filename character set, which
 234    consists of A-Z, a-z, 0-9, ., _, - (plus / for separators).
 235
 236    If CHECK_BASIC_PORTABILITY is false, make sure that all leading directories
 237    along FILE that exist are searchable.
 238
 239    If CHECK_EXTRA_PORTABILITY is true, check that file name components do not
 240    begin with "-".
 241
 242    If either CHECK_BASIC_PORTABILITY or CHECK_EXTRA_PORTABILITY is true,
 243    check that the file name is not empty.
 244
 245    Return true if all of these tests are successful, false if any fail.  */
 246
 247 static bool
 248 validate_file_name (char *file, bool check_basic_portability,
 249                     bool check_extra_portability)
 250 {
 251   size_t filelen = strlen (file);
 252
 253   /* Start of file name component being checked.  */
 254   char *start;
 255
 256   /* True if component lengths need to be checked.  */
 257   bool check_component_lengths;
 258
 259   /* True if the file is known to exist.  */
 260   bool file_exists = false;
 261
 262   if (check_extra_portability && ! no_leading_hyphen (file))
 263     return false;
 264
 265   if ((check_basic_portability || check_extra_portability)
 266       && filelen == 0)
 267     {
 268       /* Fail, since empty names are not portable.  As of
 269          2005-01-06 POSIX does not address whether "pathchk -p ''"
 270          should (or is allowed to) fail, so this is not a
 271          conformance violation.  */
 272       error (0, 0, _("empty file name"));
 273       return false;
 274     }
 275
 276   if (check_basic_portability)
 277     {
 278       if (! portable_chars_only (file, filelen))
 279         return false;
 280     }
 281   else
 282     {
 283       /* Check whether a file name component is in a directory that
 284          is not searchable, or has some other serious problem.
 285          POSIX does not allow "" as a file name, but some non-POSIX
 286          hosts do (as an alias for "."), so allow "" if lstat does.  */
 287
 288       struct stat st;
 289       if (lstat (file, &st) == 0)
 290         file_exists = true;
 291       else if (errno != ENOENT || filelen == 0)
 292         {
 293           error (0, errno, "%s", file);
 294           return false;
 295         }
 296     }
 297
 298   if (check_basic_portability
 299       || (! file_exists && PATH_MAX_MINIMUM <= filelen))
 300     {
 301       size_t maxsize;
 302
 303       if (check_basic_portability)
 304         maxsize = _POSIX_PATH_MAX;
 305       else
 306         {
 307           long int size;
 308           char const *dir = (*file == '/' ? "/" : ".");
 309           errno = 0;
 310           size = pathconf (dir, _PC_PATH_MAX);
 311           if (size < 0 && errno != 0)
 312             {
 313               error (0, errno,
 314                      _("%s: unable to determine maximum file name length"),
 315                      dir);
 316               return false;
 317             }
 318           maxsize = MIN (size, SSIZE_MAX);
 319         }
 320
 321       if (maxsize <= filelen)
 322         {
 323           unsigned long int len = filelen;
 324           unsigned long int maxlen = maxsize - 1;
 325           error (0, 0, _("limit %lu exceeded by length %lu of file name %s"),
 326                  maxlen, len, quote (file));
 327           return false;
 328         }
 329     }
 330
 331   /* Check whether pathconf (..., _PC_NAME_MAX) can be avoided, i.e.,
 332      whether all file name components are so short that they are valid
 333      in any file system on this platform.  If CHECK_BASIC_PORTABILITY, though,
 334      it's more convenient to check component lengths below.  */
 335
 336   check_component_lengths = check_basic_portability;
 337   if (! check_component_lengths && ! file_exists)
 338     {
 339       for (start = file; *(start = component_start (start)); )
 340         {
 341           size_t length = component_len (start);
 342
 343           if (NAME_MAX_MINIMUM < length)
 344             {
 345               check_component_lengths = true;
 346               break;
 347             }
 348
 349           start += length;
 350         }
 351     }
 352
 353   if (check_component_lengths)
 354     {
 355       /* The limit on file name components for the current component.
 356          This defaults to NAME_MAX_MINIMUM, for the sake of non-POSIX
 357          systems (NFS, say?) where pathconf fails on "." or "/" with
 358          errno == ENOENT.  */
 359       size_t name_max = NAME_MAX_MINIMUM;
 360
 361       /* If nonzero, the known limit on file name components.  */
 362       size_t known_name_max = (check_basic_portability ? _POSIX_NAME_MAX : 0);
 363
 364       for (start = file; *(start = component_start (start)); )
 365         {
 366           size_t length;
 367
 368           if (known_name_max)
 369             name_max = known_name_max;
 370           else
 371             {
 372               long int len;
 373               char const *dir = (start == file ? "." : file);
 374               char c = *start;
 375               errno = 0;
 376               *start = '\0';
 377               len = pathconf (dir, _PC_NAME_MAX);
 378               *start = c;
 379               if (0 <= len)
 380                 name_max = MIN (len, SSIZE_MAX);
 381               else
 382                 switch (errno)
 383                   {
 384                   case 0:
 385                     /* There is no limit.  */
 386                     name_max = SIZE_MAX;
 387                     break;
 388
 389                   case ENOENT:
 390                     /* DIR does not exist; use its parent's maximum.  */
 391                     known_name_max = name_max;
 392                     break;
 393
 394                   default:
 395                     *start = '\0';
 396                     error (0, errno, "%s", dir);
 397                     *start = c;
 398                     return false;
 399                   }
 400             }
 401
 402           length = component_len (start);
 403
 404           if (name_max < length)
 405             {
 406               unsigned long int len = length;
 407               unsigned long int maxlen = name_max;
 408               char c = start[len];
 409               start[len] = '\0';
 410               error (0, 0,
 411                      _("limit %lu exceeded by length %lu "
 412                        "of file name component %s"),
 413                      maxlen, len, quote (start));
 414               start[len] = c;
 415               return false;
 416             }
 417
 418           start += length;
 419         }
 420     }
 421
 422   return true;
 423 }