src/printenv.c

   1 /* printenv -- print all or part of environment
   2    Copyright (C) 1989-1997, 1999-2005, 2007-2009 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 /* Usage: printenv [variable...]
  18
  19    If no arguments are given, print the entire environment.
  20    If one or more variable names are given, print the value of
  21    each one that is set, and nothing for ones that are not set.
  22
  23    Exit status:
  24    0 if all variables specified were found
  25    1 if not
  26    2 if some other error occurred
  27
  28    David MacKenzie and Richard Mlynarik */
  29
  30 #include <config.h>
  31 #include <stdio.h>
  32 #include <sys/types.h>
  33 #include <getopt.h>
  34
  35 #include "system.h"
  36 #include "long-options.h"
  37
  38 /* Exit status for syntax errors, etc.  */
  39 enum { PRINTENV_FAILURE = 2 };
  40
  41 /* The official name of this program (e.g., no `g' prefix).  */
  42 #define PROGRAM_NAME "printenv"
  43
  44 #define AUTHORS \
  45   proper_name ("David MacKenzie"), \
  46   proper_name ("Richard Mlynarik")
  47
  48 extern char **environ;
  49
  50 void
  51 usage (int status)
  52 {
  53   if (status != EXIT_SUCCESS)
  54     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  55              program_name);
  56   else
  57     {
  58       printf (_("\
  59 Usage: %s [VARIABLE]...\n\
  60   or:  %s OPTION\n\
  61 Print the values of the specified environment VARIABLE(s).\n\
  62 If no VARIABLE is specified, print name and value pairs for them all.\n\
  63 \n\
  64 "),
  65               program_name, program_name);
  66       fputs (HELP_OPTION_DESCRIPTION, stdout);
  67       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  68       printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
  69       emit_bug_reporting_address ();
  70     }
  71   exit (status);
  72 }
  73
  74 int
  75 main (int argc, char **argv)
  76 {
  77   char **env;
  78   char *ep, *ap;
  79   int i;
  80   bool ok;
  81
  82   initialize_main (&argc, &argv);
  83   set_program_name (argv[0]);
  84   setlocale (LC_ALL, "");
  85   bindtextdomain (PACKAGE, LOCALEDIR);
  86   textdomain (PACKAGE);
  87
  88   initialize_exit_failure (PRINTENV_FAILURE);
  89   atexit (close_stdout);
  90
  91   parse_long_options (argc, argv, PROGRAM_NAME, PACKAGE_NAME, Version,
  92                       usage, AUTHORS, (char const *) NULL);
  93   if (getopt_long (argc, argv, "+", NULL, NULL) != -1)
  94     usage (PRINTENV_FAILURE);
  95
  96   if (optind >= argc)
  97     {
  98       for (env = environ; *env != NULL; ++env)
  99         puts (*env);
 100       ok = true;
 101     }
 102   else
 103     {
 104       int matches = 0;
 105
 106       for (i = optind; i < argc; ++i)
 107         {
 108           bool matched = false;
 109
 110           for (env = environ; *env; ++env)
 111             {
 112               ep = *env;
 113               ap = argv[i];
 114               while (*ep != '\0' && *ap != '\0' && *ep++ == *ap++)
 115                 {
 116                   if (*ep == '=' && *ap == '\0')
 117                     {
 118                       puts (ep + 1);
 119                       matched = true;
 120                       break;
 121                     }
 122                 }
 123             }
 124
 125           matches += matched;
 126         }
 127
 128       ok = (matches == argc - optind);
 129     }
 130
 131   exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 132 }