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Diffstat (limited to 'src/env.c')
| -rw-r--r-- | src/env.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/src/env.c b/src/env.c new file mode 100644 index 0000000..d95ebfd --- /dev/null +++ b/src/env.c @@ -0,0 +1,205 @@ +/* env - run a program in a modified environment + Copyright (C) 1986, 1991-2005, 2007 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 2, 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, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* Richard Mlynarik and David MacKenzie */ + +/* Options: + - + -i + --ignore-environment + Construct a new environment from scratch; normally the + environment is inherited from the parent process, except as + modified by other options. + + -u variable + --unset=variable + Unset variable VARIABLE (remove it from the environment). + If VARIABLE was not set, does nothing. + + variable=value (an arg containing a "=" character) + Set the environment variable VARIABLE to value VALUE. VALUE + may be of zero length ("variable="). Setting a variable to a + zero-length value is different from unsetting it. + + -- + Indicate that the following argument is the program + to invoke. This is necessary when the program's name + begins with "-" or contains a "=". + + The first remaining argument specifies a program to invoke; + it is searched for according to the specification of the PATH + environment variable. Any arguments following that are + passed as arguments to that program. + + If no command name is specified following the environment + specifications, the resulting environment is printed. + This is like specifying a command name of "printenv". + + Examples: + + If the environment passed to "env" is + { LOGNAME=rms EDITOR=emacs PATH=.:/gnubin:/hacks } + + env - foo + runs "foo" in a null environment. + + env foo + runs "foo" in the environment + { LOGNAME=rms EDITOR=emacs PATH=.:/gnubin:/hacks } + + env DISPLAY=gnu:0 nemacs + runs "nemacs" in the environment + { LOGNAME=rms EDITOR=emacs PATH=.:/gnubin:/hacks DISPLAY=gnu:0 } + + env - LOGNAME=foo /hacks/hack bar baz + runs the "hack" program on arguments "bar" and "baz" in an + environment in which the only variable is "LOGNAME". Note that + the "-" option clears out the PATH variable, so one should be + careful to specify in which directory to find the program to + call. + + env -u EDITOR LOGNAME=foo PATH=/energy -- e=mc2 bar baz + runs the program "/energy/e=mc2" with environment + { LOGNAME=foo PATH=/energy } +*/ + +#include <config.h> +#include <stdio.h> +#include <getopt.h> +#include <sys/types.h> +#include <getopt.h> + +#include "system.h" +#include "error.h" + +/* The official name of this program (e.g., no `g' prefix). */ +#define PROGRAM_NAME "env" + +#define AUTHORS "Richard Mlynarik", "David MacKenzie" + +int putenv (); + +extern char **environ; + +/* The name by which this program was run. */ +char *program_name; + +static struct option const longopts[] = +{ + {"ignore-environment", no_argument, NULL, 'i'}, + {"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) + fprintf (stderr, _("Try `%s --help' for more information.\n"), + program_name); + 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\ +\n\ + -i, --ignore-environment start with an empty environment\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); + printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT); + } + exit (status); +} + +int +main (int argc, char **argv) +{ + int optc; + bool ignore_environment = false; + + initialize_main (&argc, &argv); + program_name = argv[0]; + setlocale (LC_ALL, ""); + bindtextdomain (PACKAGE, LOCALEDIR); + textdomain (PACKAGE); + + initialize_exit_failure (EXIT_FAIL); + atexit (close_stdout); + + while ((optc = getopt_long (argc, argv, "+iu:", longopts, NULL)) != -1) + { + switch (optc) + { + case 'i': + ignore_environment = true; + break; + case 'u': + break; + case_GETOPT_HELP_CHAR; + case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS); + default: + usage (EXIT_FAIL); + } + } + + 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:", longopts, NULL)) != -1) + if (optc == 'u') + putenv (optarg); /* Requires GNU putenv. */ + + if (optind < argc && STREQ (argv[optind], "-")) + ++optind; + + while (optind < argc && strchr (argv[optind], '=')) + putenv (argv[optind++]); + + /* If no program is specified, print the environment and exit. */ + if (argc <= optind) + { + char *const *e = environ; + while (*e) + puts (*e++); + exit (EXIT_SUCCESS); + } + + execvp (argv[optind], &argv[optind]); + + { + int exit_status = (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE); + error (0, errno, "%s", argv[optind]); + exit (exit_status); + } +} |