lib/libc/gen/confstr.c

   1 /*-
   2  * Copyright (c) 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. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * @(#)confstr.c        8.1 (Berkeley) 6/4/93
  34  * $DragonFly: src/lib/libc/gen/confstr.c,v 1.5 2006/12/06 16:33:29 tgen Exp $
  35  */
  36
  37 #include <sys/param.h>
  38 #include <sys/sysctl.h>
  39
  40 #include <errno.h>
  41 #include <paths.h>
  42 #include <stdlib.h>
  43 #include <unistd.h>
  44 #include <string.h>
  45
  46 size_t
  47 confstr(int name, char *buf, size_t len)
  48 {
  49         size_t tlen;
  50         int mib[2], sverrno;
  51         char *p;
  52
  53         switch (name) {
  54         case _CS_PATH:
  55                 mib[0] = CTL_USER;
  56                 mib[1] = USER_CS_PATH;
  57                 if (sysctl(mib, 2, NULL, &tlen, NULL, 0) == -1)
  58                         /*
  59                          * SUSv3 requires errors to return 0.
  60                          */
  61                         return (0);
  62                 if (len != 0 && buf != NULL) {
  63                         if ((p = malloc(tlen)) == NULL)
  64                                 return (0);     /* SUSv3 */
  65                         if (sysctl(mib, 2, p, &tlen, NULL, 0) == -1) {
  66                                 sverrno = errno;
  67                                 free(p);
  68                                 errno = sverrno;
  69                                 return (0);     /* SUSv3 */
  70                         }
  71                         /*
  72                          * POSIX 1003.2 requires partial return of
  73                          * the string -- that should be *real* useful.
  74                          */
  75                         strncpy(buf, p, len - 1);
  76                         buf[len - 1] = '\0';
  77                         free(p);
  78                 }
  79                 return (tlen + 1);
  80         default:
  81                 errno = EINVAL;
  82                 return (0);
  83         }
  84         /* NOTREACHED */
  85 }