commands/env/env.c

   1 /*      env 1.1 - Set environment for command           Author: Kees J. Bot
   2  *                                                              17 Dec 1997
   3  */
   4 #define nil 0
   5 #include <sys/types.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <unistd.h>
  10 #include <errno.h>
  11
  12 int main(int argc, char **argv)
  13 {
  14         int i;
  15         int iflag= 0;
  16         int aflag= 0;
  17         extern char **environ;
  18
  19         i= 1;
  20         while (i < argc && argv[i][0] == '-') {
  21                 char *opt= argv[i++] + 1;
  22
  23                 if (opt[0] == '-' && opt[1] == 0) break;        /* -- */
  24
  25                 if (opt[0] == 0) iflag= 1;                      /* - */
  26
  27                 while (*opt != 0) switch (*opt++) {
  28                 case 'i':
  29                         iflag= 1;       /* Clear environment. */
  30                         break;
  31                 case 'a':               /* Specify arg 0 separately. */
  32                         aflag= 1;
  33                         break;
  34                 default:
  35                         fprintf(stderr,
  36                 "Usage: env [-ia] [name=value] ... [utility [argument ...]]\n");
  37                         exit(1);
  38                 }
  39         }
  40
  41         /* Clear the environment if -i. */
  42         if (iflag) *environ= nil;
  43
  44         /* Set the new environment strings. */
  45         while (i < argc && strchr(argv[i], '=') != nil) {
  46                 if (putenv(argv[i]) != 0) {
  47                         fprintf(stderr, "env: Setting '%s' failed: %s\n",
  48                                 argv[i], strerror(errno));
  49                         exit(1);
  50                 }
  51                 i++;
  52         }
  53
  54         /* Environment settings and command may be separated with '--'.
  55          * This is for compatibility with other envs, we don't advertise it.
  56          */
  57         if (i < argc && strcmp(argv[i], "--") == 0) i++;
  58
  59         if (i >= argc) {
  60                 /* No utility given; print environment. */
  61                 char **ep;
  62
  63                 for (ep= environ; *ep != nil; ep++) {
  64                         if (puts(*ep) == EOF) {
  65                                 fprintf(stderr, "env: %s\n", strerror(errno));
  66                                 exit(1);
  67                         }
  68                 }
  69                 return 0;
  70         } else {
  71                 char *util, **args;
  72                 int err;
  73
  74                 util= argv[i];
  75                 args= argv + i;
  76                 if (aflag) args++;
  77                 (void) execvp(util, args);
  78                 err= errno;
  79                 fprintf(stderr, "env: Can't execute %s: %s\n",
  80                         util, strerror(err));
  81                 return err == ENOENT ? 127 : 126;
  82         }
  83 }