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
  11//usage:#define printenv_trivial_usage
  12//usage:       "[VARIABLE]..."
  13//usage:#define printenv_full_usage "\n\n"
  14//usage:       "Print environment VARIABLEs.\n"
  15//usage:       "If no VARIABLE specified, print all."
  16
  17#include "libbb.h"
  18
  19/* This is a NOFORK applet. Be very careful! */
  20
  21int printenv_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  22int printenv_main(int argc UNUSED_PARAM, char **argv)
  23{
  24        int exit_code = EXIT_SUCCESS;
  25
  26        /* no variables specified, show whole env */
  27        if (!argv[1]) {
  28                char **e = environ;
  29
  30                /* environ can be NULL! (for example, after clearenv())
  31                 * Check for that:
  32                 */
  33                if (e)
  34                        while (*e)
  35                                puts(*e++);
  36        } else {
  37                /* search for specified variables and print them out if found */
  38                char *arg, *env;
  39
  40                while ((arg = *++argv) != NULL) {
  41                        env = getenv(arg);
  42                        if (env)
  43                                puts(env);
  44                        else
  45                                exit_code = EXIT_FAILURE;
  46                }
  47        }
  48
  49        fflush_stdout_and_exit(exit_code);
  50}
  51