gen/FreeBSD/sysctlbyname.c

   1 /*
   2  * ----------------------------------------------------------------------------
   3  * "THE BEER-WARE LICENSE" (Revision 42):
   4  * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
   5  * can do whatever you want with this stuff. If we meet some day, and you think
   6  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
   7  * ----------------------------------------------------------------------------
   8  *
   9  */
  10
  11 #include <sys/cdefs.h>
  12 __FBSDID("$FreeBSD: src/lib/libc/gen/sysctlbyname.c,v 1.5 2002/02/01 00:57:29 obrien Exp $");
  13
  14 #include <sys/types.h>
  15 #include <sys/sysctl.h>
  16 #include <string.h>
  17
  18 int
  19 sysctlbyname(const char *name, void *oldp, size_t *oldlenp, void *newp,
  20              size_t newlen)
  21 {
  22         int name2oid_oid[2];
  23         int real_oid[CTL_MAXNAME+2];
  24         int error;
  25         size_t oidlen;
  26
  27         name2oid_oid[0] = 0;    /* This is magic & undocumented! */
  28         name2oid_oid[1] = 3;
  29
  30         oidlen = sizeof(real_oid);
  31         error = sysctl(name2oid_oid, 2, real_oid, &oidlen, (void *)name,
  32                        strlen(name));
  33         if (error < 0)
  34                 return error;
  35         oidlen /= sizeof (int);
  36         error = sysctl(real_oid, oidlen, oldp, oldlenp, newp, newlen);
  37         return (error);
  38 }
  39