usr.bin/kenv/kenv.c

   1 /*
   2  * Copyright (c) 2000  Peter Wemm <peter@freebsd.org>
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  23  * SUCH DAMAGE.
  24  *
  25  * $FreeBSD: src/usr.bin/kenv/kenv.c,v 1.1.2.2 2001/12/19 04:52:15 dd Exp $
  26  * $DragonFly: src/usr.bin/kenv/kenv.c,v 1.3 2005/02/25 14:55:51 joerg Exp $
  27  */
  28 #include <sys/types.h>
  29 #include <sys/sysctl.h>
  30 #include <stdlib.h>
  31 #include <stdio.h>
  32 #include <string.h>
  33 #include <errno.h>
  34 #include <err.h>
  35 #include <unistd.h>
  36
  37 static char sbuf[1024];
  38
  39 static void
  40 usage(void)
  41 {
  42         (void)fprintf(stderr, "usage: kenv [-h] [variable]\n");
  43         exit(1);
  44 }
  45
  46 int
  47 main(int argc, char **argv)
  48 {
  49         int real_oid[CTL_MAXNAME];
  50         size_t oidlen;
  51         int ch, error, hflag, i, slen;
  52         char *env, *eq, *var, *val;
  53
  54         hflag = 0;
  55         env = NULL;
  56         while ((ch = getopt(argc, argv, "h")) != -1) {
  57                 switch (ch) {
  58                 case 'h':
  59                         hflag++;
  60                         break;
  61                 default:
  62                         usage();
  63                 }
  64         }
  65         argc -= optind;
  66         argv += optind;
  67         if (argc > 0) {
  68                 env = argv[0];
  69                 argv++;
  70                 argc--;
  71         }
  72         if (argc > 0)
  73                 usage();
  74         oidlen = __arysize(real_oid);
  75         error = sysctlnametomib("kern.environment", real_oid, &oidlen);
  76         if (error)
  77                 err(1, "cannot find kern.environment base sysctl OID");
  78         if (oidlen + 1 >= __arysize(real_oid))
  79                 errx(1, "kern.environment base OID too large");
  80         real_oid[oidlen] = 0;
  81         for (i = 0; ; i++) {
  82                 real_oid[oidlen + 1] = i;
  83                 slen = sizeof(sbuf) - 1;
  84                 error = sysctl(real_oid, oidlen + 2, sbuf, &slen, NULL, 0);
  85                 if (error < 0) {
  86                         if (errno != ENOENT)
  87                                 err(1, "sysctl kern.environment.%d\n", i);
  88                         break;
  89                 }
  90                 sbuf[sizeof(sbuf) - 1] = '\0';
  91                 eq = strchr(sbuf, '=');
  92                 if (eq == NULL)
  93                         err(1, "malformed environment string: %s\n", sbuf);
  94                 var = sbuf;
  95                 *eq = '\0';
  96                 val = eq + 1;
  97                 if (env) {
  98                         if (strcmp(var, env) != 0)
  99                                 continue;
 100                         printf("%s\n", val);
 101                         break;
 102                 }
 103                 if (hflag) {
 104                         if (strncmp(var, "hint.", 5) != 0)
 105                                 continue;
 106                         /* FALLTHROUGH */
 107                 }
 108                 printf("%s=\"", var);
 109                 while (*val) {
 110                         switch (*val) {
 111                         case '"':
 112                                 putchar('\\');
 113                                 putchar('"');
 114                                 break;
 115                         case '\\':
 116                                 putchar('\\');
 117                                 putchar('\\');
 118                                 break;
 119                         default:
 120                                 putchar(*val);
 121                                 break;
 122                         }
 123                         val++;
 124                 }
 125                 printf("\"\n");
 126         }
 127         exit(0);
 128 }