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Diffstat (limited to 'src/printenv.c')
| -rw-r--r-- | src/printenv.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/src/printenv.c b/src/printenv.c new file mode 100644 index 0000000..0cc8a48 --- /dev/null +++ b/src/printenv.c @@ -0,0 +1,154 @@ +/* printenv -- print all or part of environment + Copyright (C) 1989-2018 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 <https://www.gnu.org/licenses/>. */ + +/* Usage: printenv [variable...] + + If no arguments are given, print the entire environment. + If one or more variable names are given, print the value of + each one that is set, and nothing for ones that are not set. + + Exit status: + 0 if all variables specified were found + 1 if not + 2 if some other error occurred + + David MacKenzie and Richard Mlynarik */ + +#include <config.h> +#include <stdio.h> +#include <sys/types.h> +#include <getopt.h> + +#include "system.h" + +/* Exit status for syntax errors, etc. */ +enum { PRINTENV_FAILURE = 2 }; + +/* The official name of this program (e.g., no 'g' prefix). */ +#define PROGRAM_NAME "printenv" + +#define AUTHORS \ + proper_name ("David MacKenzie"), \ + proper_name ("Richard Mlynarik") + +static struct option const longopts[] = +{ + {"null", no_argument, NULL, '0'}, + {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]... [VARIABLE]...\n\ +Print the values of the specified environment VARIABLE(s).\n\ +If no VARIABLE is specified, print name and value pairs for them all.\n\ +\n\ +"), + program_name); + fputs (_("\ + -0, --null end each output line with NUL, not newline\n\ +"), stdout); + fputs (HELP_OPTION_DESCRIPTION, stdout); + fputs (VERSION_OPTION_DESCRIPTION, stdout); + printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME); + emit_ancillary_info (PROGRAM_NAME); + } + exit (status); +} + +int +main (int argc, char **argv) +{ + char **env; + char *ep, *ap; + int i; + bool ok; + int optc; + 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 (PRINTENV_FAILURE); + atexit (close_stdout); + + while ((optc = getopt_long (argc, argv, "+iu:0", longopts, NULL)) != -1) + { + switch (optc) + { + case '0': + opt_nul_terminate_output = true; + break; + case_GETOPT_HELP_CHAR; + case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS); + default: + usage (PRINTENV_FAILURE); + } + } + + if (optind >= argc) + { + for (env = environ; *env != NULL; ++env) + printf ("%s%c", *env, opt_nul_terminate_output ? '\0' : '\n'); + ok = true; + } + else + { + int matches = 0; + + for (i = optind; i < argc; ++i) + { + bool matched = false; + + /* 'printenv a=b' is silent, even if 'a=b=c' is in environ. */ + if (strchr (argv[i], '=')) + continue; + + for (env = environ; *env; ++env) + { + ep = *env; + ap = argv[i]; + while (*ep != '\0' && *ap != '\0' && *ep++ == *ap++) + { + if (*ep == '=' && *ap == '\0') + { + printf ("%s%c", ep + 1, + opt_nul_terminate_output ? '\0' : '\n'); + matched = true; + break; + } + } + } + + matches += matched; + } + + ok = (matches == argc - optind); + } + + return ok ? EXIT_SUCCESS : EXIT_FAILURE; +} |