libbb/kernel_version.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Utility routines.
   4  *
   5  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8  */
   9 #include "libbb.h"
  10 /* After libbb.h, since it needs sys/types.h on some systems */
  11 #include <sys/utsname.h>  /* for uname(2) */
  12
  13 /* Returns current kernel version encoded as major*65536 + minor*256 + patch,
  14  * so, for example,  to check if the kernel is greater than 2.2.11:
  15  *
  16  *     if (get_linux_version_code() > KERNEL_VERSION(2,2,11)) { <stuff> }
  17  */
  18 int FAST_FUNC get_linux_version_code(void)
  19 {
  20         struct utsname name;
  21         char *t;
  22         int r;
  23
  24         uname(&name); /* never fails */
  25         t = name.release - 1;
  26         r = 1;
  27         do {
  28                 r <<= 8;
  29                 if (t) {
  30                         r += atoi(++t);
  31                         t = strchr(t, '.');
  32                 }
  33         } while (r < 0x1000000);
  34         return r - 0x1000000;
  35 }