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root/usr/bin/printenv/printenv.c

DEFINITIONS

1. main
2. usage

   1 /*
   2  * Copyright (c) 1987, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  30 #include <unistd.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  35 extern char     **environ;
  37 static void usage(void);
  40 #ifdef CMDBOX
  41 #define main(argc, argv)        printenv_main(argc, argv)
  42 #endif
  44 /*
  45  * printenv
  46  *
  47  * Bill Joy, UCB
  48  * February, 1979
  49  */
  50 int
main(int argc, char *argv[])
  52 {
  53         char *cp, **ep;
size_t len;
  55         int ch;
  57         while ((ch = getopt(argc, argv, "")) != EOF)
  58                 switch(ch) {
  59                 case '?':
  60                 default:
usage();
  62                 }
argc -= optind;
argv += optind;
  66         if (argc == 0) {
  67                 for (ep = environ; *ep; ep++)
  68                         (void)printf("%s\n", *ep);
exit(0);
  70         }
len = strlen(*argv);
  72         for (ep = environ; *ep; ep++)
  73                 if (!memcmp(*ep, *argv, len)) {
cp = *ep + len;
  75                         if (!*cp || *cp == '=') {
  76                                 (void)printf("%s\n", *cp ? cp + 1 : cp);
exit(0);
  78                         }
  79                 }
exit(1);
  81 }
  83 static void
usage(void)
  85 {
  86         (void)fprintf(stderr, "usage: printenv [name]\n");
exit(1);
  88 }