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 1.2 2003/06/17 04:29:27 dillon 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 name2oid_oid[2];
  50         int real_oid[CTL_MAXNAME+4];
  51         size_t oidlen;
  52         int ch, error, hflag, i, slen;
  53         char *env, *eq, *name, *var, *val;
  54
  55         hflag = 0;
  56         env = NULL;
  57         while ((ch = getopt(argc, argv, "h")) != -1) {
  58                 switch (ch) {
  59                 case 'h':
  60                         hflag++;
  61                         break;
  62                 default:
  63                         usage();
  64                 }
  65         }
  66         argc -= optind;
  67         argv += optind;
  68         if (argc > 0) {
  69                 env = argv[0];
  70                 argv++;
  71                 argc--;
  72         }
  73         if (argc > 0)
  74                 usage();
  75         name2oid_oid[0] = 0;    /* This is magic & undocumented! */
  76         name2oid_oid[1] = 3;
  77         oidlen = sizeof(real_oid);
  78         name = "kern.environment";
  79         error = sysctl(name2oid_oid, 2, real_oid, &oidlen, name, strlen(name));
  80         if (error < 0)
  81                 err(1, "cannot find kern.environment base sysctl OID");
  82         oidlen /= sizeof (int);
  83         if (oidlen >= CTL_MAXNAME)
  84                 errx(1, "kern.environment OID is too large!");
  85         real_oid[oidlen] = 0;
  86         for (i = 0; ; i++) {
  87                 real_oid[oidlen + 1] = i;
  88                 slen = sizeof(sbuf) - 1;
  89                 error = sysctl(real_oid, oidlen + 2, sbuf, &slen, NULL, 0);
  90                 if (error < 0) {
  91                         if (errno != ENOENT)
  92                                 err(1, "sysctl kern.environment.%d\n", i);
  93                         break;
  94                 }
  95                 sbuf[sizeof(sbuf) - 1] = '\0';
  96                 eq = strchr(sbuf, '=');
  97                 if (eq == NULL)
  98                         err(1, "malformed environment string: %s\n", sbuf);
  99                 var = sbuf;
 100                 *eq = '\0';
 101                 val = eq + 1;
 102                 if (env) {
 103                         if (strcmp(var, env) != 0)
 104                                 continue;
 105                         printf("%s\n", val);
 106                         break;
 107                 }
 108                 if (hflag) {
 109                         if (strncmp(var, "hint.", 5) != 0)
 110                                 continue;
 111                         /* FALLTHROUGH */
 112                 }
 113                 printf("%s=\"", var);
 114                 while (*val) {
 115                         switch (*val) {
 116                         case '"':
 117                                 putchar('\\');
 118                                 putchar('"');
 119                                 break;
 120                         case '\\':
 121                                 putchar('\\');
 122                                 putchar('\\');
 123                                 break;
 124                         default:
 125                                 putchar(*val);
 126                                 break;
 127                         }
 128                         val++;
 129                 }
 130                 printf("\"\n");
 131         }
 132         exit(0);
 133 }