src/basename.c

   1 /* basename -- strip directory and suffix from file names
   2    Copyright (C) 1990-2023 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 <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18 #include <getopt.h>
  19 #include <stdio.h>
  20 #include <sys/types.h>
  21
  22 #include "system.h"
  23 #include "quote.h"
  24
  25 /* The official name of this program (e.g., no 'g' prefix).  */
  26 #define PROGRAM_NAME "basename"
  27
  28 #define AUTHORS proper_name ("David MacKenzie")
  29
  30 static struct option const longopts[] =
  31 {
  32   {"multiple", no_argument, nullptr, 'a'},
  33   {"suffix", required_argument, nullptr, 's'},
  34   {"zero", no_argument, nullptr, 'z'},
  35   {GETOPT_HELP_OPTION_DECL},
  36   {GETOPT_VERSION_OPTION_DECL},
  37   {nullptr, 0, nullptr, 0}
  38 };
  39
  40 void
  41 usage (int status)
  42 {
  43   if (status != EXIT_SUCCESS)
  44     emit_try_help ();
  45   else
  46     {
  47       printf (_("\
  48 Usage: %s NAME [SUFFIX]\n\
  49   or:  %s OPTION... NAME...\n\
  50 "),
  51               program_name, program_name);
  52       fputs (_("\
  53 Print NAME with any leading directory components removed.\n\
  54 If specified, also remove a trailing SUFFIX.\n\
  55 "), stdout);
  56
  57       emit_mandatory_arg_note ();
  58
  59       fputs (_("\
  60   -a, --multiple       support multiple arguments and treat each as a NAME\n\
  61   -s, --suffix=SUFFIX  remove a trailing SUFFIX; implies -a\n\
  62   -z, --zero           end each output line with NUL, not newline\n\
  63 "), stdout);
  64       fputs (HELP_OPTION_DESCRIPTION, stdout);
  65       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  66       printf (_("\
  67 \n\
  68 Examples:\n\
  69   %s /usr/bin/sort          -> \"sort\"\n\
  70   %s include/stdio.h .h     -> \"stdio\"\n\
  71   %s -s .h include/stdio.h  -> \"stdio\"\n\
  72   %s -a any/str1 any/str2   -> \"str1\" followed by \"str2\"\n\
  73 "),
  74               program_name, program_name, program_name, program_name);
  75       emit_ancillary_info (PROGRAM_NAME);
  76     }
  77   exit (status);
  78 }
  79
  80 /* Remove SUFFIX from the end of NAME if it is there, unless NAME
  81    consists entirely of SUFFIX.  */
  82
  83 static void
  84 remove_suffix (char *name, char const *suffix)
  85 {
  86   char *np;
  87   char const *sp;
  88
  89   np = name + strlen (name);
  90   sp = suffix + strlen (suffix);
  91
  92   while (np > name && sp > suffix)
  93     if (*--np != *--sp)
  94       return;
  95   if (np > name)
  96     *np = '\0';
  97 }
  98
  99 /* Perform the basename operation on STRING.  If SUFFIX is non-null, remove
 100    the trailing SUFFIX.  Finally, output the result string.  */
 101
 102 static void
 103 perform_basename (char const *string, char const *suffix, bool use_nuls)
 104 {
 105   char *name = base_name (string);
 106   strip_trailing_slashes (name);
 107
 108   /* Per POSIX, 'basename // /' must return '//' on platforms with
 109      distinct //.  On platforms with drive letters, this generalizes
 110      to making 'basename c: :' return 'c:'.  This rule is captured by
 111      skipping suffix stripping if base_name returned an absolute path
 112      or a drive letter (only possible if name is a file-system
 113      root).  */
 114   if (suffix && IS_RELATIVE_FILE_NAME (name) && ! FILE_SYSTEM_PREFIX_LEN (name))
 115     remove_suffix (name, suffix);
 116
 117   fputs (name, stdout);
 118   putchar (use_nuls ? '\0' : '\n');
 119   free (name);
 120 }
 121
 122 int
 123 main (int argc, char **argv)
 124 {
 125   bool multiple_names = false;
 126   bool use_nuls = false;
 127   char const *suffix = nullptr;
 128
 129   initialize_main (&argc, &argv);
 130   set_program_name (argv[0]);
 131   setlocale (LC_ALL, "");
 132   bindtextdomain (PACKAGE, LOCALEDIR);
 133   textdomain (PACKAGE);
 134
 135   atexit (close_stdout);
 136
 137   while (true)
 138     {
 139       int c = getopt_long (argc, argv, "+as:z", longopts, nullptr);
 140
 141       if (c == -1)
 142         break;
 143
 144       switch (c)
 145         {
 146         case 's':
 147           suffix = optarg;
 148           /* -s implies -a, so...  */
 149           FALLTHROUGH;
 150
 151         case 'a':
 152           multiple_names = true;
 153           break;
 154
 155         case 'z':
 156           use_nuls = true;
 157           break;
 158
 159         case_GETOPT_HELP_CHAR;
 160         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 161
 162         default:
 163           usage (EXIT_FAILURE);
 164         }
 165     }
 166
 167   if (argc < optind + 1)
 168     {
 169       error (0, 0, _("missing operand"));
 170       usage (EXIT_FAILURE);
 171     }
 172
 173   if (!multiple_names && optind + 2 < argc)
 174     {
 175       error (0, 0, _("extra operand %s"), quote (argv[optind + 2]));
 176       usage (EXIT_FAILURE);
 177     }
 178
 179   if (multiple_names)
 180     {
 181       for (; optind < argc; optind++)
 182         perform_basename (argv[optind], suffix, use_nuls);
 183     }
 184   else
 185     perform_basename (argv[optind],
 186                       optind + 2 == argc ? argv[optind + 1] : nullptr,
 187                       use_nuls);
 188
 189   return EXIT_SUCCESS;
 190 }