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/* env - run a program in a modified environment
Copyright (C) 1986-2016 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* Richard Mlynarik and David MacKenzie */
#include <config.h>
#include <stdio.h>
#include <sys/types.h>
#include <getopt.h>
#include "system.h"
#include "error.h"
#include "quote.h"
/* The official name of this program (e.g., no 'g' prefix). */
#define PROGRAM_NAME "env"
#define AUTHORS \
proper_name ("Richard Mlynarik"), \
proper_name ("David MacKenzie")
static struct option const longopts[] =
{
{"ignore-environment", no_argument, NULL, 'i'},
{"null", no_argument, NULL, '0'},
{"unset", required_argument, NULL, 'u'},
{GETOPT_HELP_OPTION_DECL},
{GETOPT_VERSION_OPTION_DECL},
{NULL, 0, NULL, 0}
};
void
usage (int status)
{
if (status != EXIT_SUCCESS)
emit_try_help ();
else
{
printf (_("\
Usage: %s [OPTION]... [-] [NAME=VALUE]... [COMMAND [ARG]...]\n"),
program_name);
fputs (_("\
Set each NAME to VALUE in the environment and run COMMAND.\n\
"), stdout);
emit_mandatory_arg_note ();
fputs (_("\
-i, --ignore-environment start with an empty environment\n\
-0, --null end each output line with NUL, not newline\n\
-u, --unset=NAME remove variable from the environment\n\
"), stdout);
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
fputs (_("\
\n\
A mere - implies -i. If no COMMAND, print the resulting environment.\n\
"), stdout);
emit_ancillary_info (PROGRAM_NAME);
}
exit (status);
}
int
main (int argc, char **argv)
{
int optc;
bool ignore_environment = false;
bool opt_nul_terminate_output = false;
initialize_main (&argc, &argv);
set_program_name (argv[0]);
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
initialize_exit_failure (EXIT_CANCELED);
atexit (close_stdout);
while ((optc = getopt_long (argc, argv, "+iu:0", longopts, NULL)) != -1)
{
switch (optc)
{
case 'i':
ignore_environment = true;
break;
case 'u':
break;
case '0':
opt_nul_terminate_output = true;
break;
case_GETOPT_HELP_CHAR;
case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
default:
usage (EXIT_CANCELED);
}
}
if (optind < argc && STREQ (argv[optind], "-"))
ignore_environment = true;
if (ignore_environment)
{
static char *dummy_environ[] = { NULL };
environ = dummy_environ;
}
optind = 0; /* Force GNU getopt to re-initialize. */
while ((optc = getopt_long (argc, argv, "+iu:0", longopts, NULL)) != -1)
if (optc == 'u' && unsetenv (optarg))
error (EXIT_CANCELED, errno, _("cannot unset %s"), quote (optarg));
if (optind < argc && STREQ (argv[optind], "-"))
++optind;
char *eq;
while (optind < argc && (eq = strchr (argv[optind], '=')))
{
if (putenv (argv[optind]))
{
*eq = '\0';
error (EXIT_CANCELED, errno, _("cannot set %s"),
quote (argv[optind]));
}
optind++;
}
/* If no program is specified, print the environment and exit. */
if (argc <= optind)
{
char *const *e = environ;
while (*e)
printf ("%s%c", *e++, opt_nul_terminate_output ? '\0' : '\n');
return EXIT_SUCCESS;
}
if (opt_nul_terminate_output)
{
error (0, errno, _("cannot specify --null (-0) with command"));
usage (EXIT_CANCELED);
}
execvp (argv[optind], &argv[optind]);
int exit_status = errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE;
error (0, errno, "%s", quote (argv[optind]));
return exit_status;
}
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