coreutils/env.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * env implementation for busybox
   4  *
   5  * Copyright (c) 1988, 1993, 1994
   6  * The Regents of the University of California.  All rights reserved.
   7  *
   8  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   9  *
  10  * Original copyright notice is retained at the end of this file.
  11  *
  12  * Modified for BusyBox by Erik Andersen <andersen@codepoet.org>
  13  */
  14 /* Mar 16, 2003      Manuel Novoa III   (mjn3@codepoet.org)
  15  *
  16  * Fixed bug involving exit return codes if execvp fails.  Also added
  17  * output error checking.
  18  */
  19 /*
  20  * Modified by Vladimir Oleynik <dzo@simtreas.ru> (C) 2003
  21  * - correct "-" option usage
  22  * - multiple "-u unsetenv" support
  23  * - GNU long option support
  24  * - use xfunc_error_retval
  25  */
  26 //config:config ENV
  27 //config:       bool "env (4.3 kb)"
  28 //config:       default y
  29 //config:       help
  30 //config:       env is used to set an environment variable and run
  31 //config:       a command; without options it displays the current
  32 //config:       environment.
  33
  34 //applet:IF_ENV(APPLET_NOEXEC(env, env, BB_DIR_USR_BIN, BB_SUID_DROP, env))
  35
  36 //kbuild:lib-$(CONFIG_ENV) += env.o
  37
  38 /* BB_AUDIT SUSv3 compliant */
  39 /* http://www.opengroup.org/onlinepubs/007904975/utilities/env.html */
  40
  41 //usage:#define env_trivial_usage
  42 //usage:       "[-i0] [-u NAME]... [-] [NAME=VALUE]... [PROG ARGS]"
  43 // The "-" can occur only once (unlike, say, -i): it terminates option processing,
  44 // so if it is followed by another "-" arg (or any option-looking arg),
  45 // that arg will be taken as PROG (or even as NAME=VALUE, example: "-z=QWE").
  46 //usage:#define env_full_usage "\n\n"
  47 //usage:       "Print current environment or run PROG after setting up environment\n"
  48 //usage:     "\n        -, -i   Start with empty environment"
  49 //usage:     "\n        -0      NUL terminated output"
  50 //usage:     "\n        -u NAME Remove variable from environment"
  51
  52 #include "libbb.h"
  53
  54 int env_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  55 int env_main(int argc UNUSED_PARAM, char **argv)
  56 {
  57         unsigned opts;
  58         llist_t *unset_env = NULL;
  59
  60         opts = getopt32long(argv, "+i0u:*",
  61                         "ignore-environment\0" No_argument       "i"
  62                         "null\0"               No_argument       "0"
  63                         "unset\0"              Required_argument "u"
  64                         , &unset_env
  65         );
  66         argv += optind;
  67         if (argv[0] && LONE_DASH(argv[0])) {
  68                 opts |= 1;
  69                 ++argv;
  70         }
  71         if (opts & 1) {
  72                 clearenv();
  73         }
  74         while (unset_env) {
  75                 char *var = llist_pop(&unset_env);
  76                 /* This does not handle -uVAR=VAL
  77                  * (coreutils _sets_ the variable in that case): */
  78                 /*unsetenv(var);*/
  79                 /* This does, but uses somewhan undocumented feature that
  80                  * putenv("name_without_equal_sign") unsets the variable: */
  81                 putenv(var);
  82         }
  83
  84         while (*argv && (strchr(*argv, '=') != NULL)) {
  85                 if (putenv(*argv) < 0) {
  86                         bb_simple_perror_msg_and_die("putenv");
  87                 }
  88                 ++argv;
  89         }
  90
  91         if (argv[0]) {
  92                 BB_EXECVP_or_die(argv);
  93         }
  94
  95         if (environ) { /* clearenv() may set environ == NULL! */
  96                 char **ep;
  97                 opts = (opts & 2) ? 0 : '\n';
  98                 for (ep = environ; *ep; ep++) {
  99                         printf("%s%c", *ep, opts);
 100                 }
 101         }
 102
 103         fflush_stdout_and_exit_SUCCESS();
 104 }
 105
 106 /*
 107  * Copyright (c) 1988, 1993, 1994
 108  *      The Regents of the University of California.  All rights reserved.
 109  *
 110  * Redistribution and use in source and binary forms, with or without
 111  * modification, are permitted provided that the following conditions
 112  * are met:
 113  * 1. Redistributions of source code must retain the above copyright
 114  *    notice, this list of conditions and the following disclaimer.
 115  * 2. Redistributions in binary form must reproduce the above copyright
 116  *    notice, this list of conditions and the following disclaimer in the
 117  *    documentation and/or other materials provided with the distribution.
 118  *
 119  * 3. BSD Advertising Clause omitted per the July 22, 1999 licensing change
 120  *    ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change
 121  *
 122  * 4. Neither the name of the University nor the names of its contributors
 123  *    may be used to endorse or promote products derived from this software
 124  *    without specific prior written permission.
 125  *
 126  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND
 127  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 128  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 129  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 130  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 131  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 132  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 133  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 134  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 135  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 136  * SUCH DAMAGE.
 137  */