LXR busybox/coreutils/printenv.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * printenv implementation for busybox
   4 *
   5 * Copyright (C) 2005 by Erik Andersen <andersen@codepoet.org>
   6 * Copyright (C) 2005 by Mike Frysinger <vapier@gentoo.org>
   7 *
   8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   9 */
  10//config:config PRINTENV
  11//config:       bool "printenv (1.3 kb)"
  12//config:       default y
  13//config:       help
  14//config:       printenv is used to print all or part of environment.
  15
  16//applet:IF_PRINTENV(APPLET_NOFORK(printenv, printenv, BB_DIR_BIN, BB_SUID_DROP, printenv))
  17
  18//kbuild:lib-$(CONFIG_PRINTENV) += printenv.o
  19
  20//usage:#define printenv_trivial_usage
  21//usage:       "[VARIABLE]..."
  22//usage:#define printenv_full_usage "\n\n"
  23//usage:       "Print environment VARIABLEs.\n"
  24//usage:       "If no VARIABLE specified, print all."
  25
  26#include "libbb.h"
  27
  28/* This is a NOFORK applet. Be very careful! */
  29
  30int printenv_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  31int printenv_main(int argc UNUSED_PARAM, char **argv)
  32{
  33        int exit_code = EXIT_SUCCESS;
  34
  35        /* no variables specified, show whole env */
  36        if (!argv[1]) {
  37                char **e = environ;
  38
  39                /* environ can be NULL! (for example, after clearenv())
  40                 * Check for that:
  41                 */
  42                if (e)
  43                        while (*e)
  44                                puts(*e++);
  45        } else {
  46                /* search for specified variables and print them out if found */
  47                char *arg, *env;
  48
  49                while ((arg = *++argv) != NULL) {
  50                        env = getenv(arg);
  51                        if (env)
  52                                puts(env);
  53                        else
  54                                exit_code = EXIT_FAILURE;
  55                }
  56        }
  57
  58        fflush_stdout_and_exit(exit_code);
  59}
  60