cpucount.c

   1 #include "cpucount.h"
   2
   3 #ifndef BSD
   4 #  ifndef __linux__
   5 // FreeBSD
   6 #    ifdef __FreeBSD__
   7 #      undef BSD
   8 #      define BSD
   9 #    endif
  10 // OpenBSD
  11 #    ifdef __OpenBSD__
  12 #      undef BSD
  13 #      define BSD
  14 #    endif
  15 // NetBSD
  16 #    ifdef __NetBSD__
  17 #      undef BSD
  18 #      define BSD
  19 #    endif
  20 // DragonFly
  21 #    ifdef __DragonFly__
  22 #      undef BSD
  23 #      define BSD
  24 #    endif
  25 #  endif // __linux__
  26 // sys/param.h may have its own define
  27 #  ifdef BSD
  28 #    undef BSD
  29 #    include <sys/param.h>
  30 #    define SYS_PARAM_INCLUDED
  31 #    ifndef BSD
  32 #      define BSD
  33 #    endif
  34 #  endif
  35 #endif // BSD
  36
  37 #ifdef BSD
  38 #  ifndef SYS_PARAM_INCLUDED
  39 #    include <sys/param.h>
  40 #  endif
  41 #  include <sys/sysctl.h>
  42 #endif
  43
  44 #include <unistd.h>
  45 #include <string.h>
  46 #include <stdio.h>
  47
  48 #ifdef __linux__
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <strings.h>
  52 static int parsecpuinfo()
  53 {
  54         unsigned char cpubitmap[128];
  55
  56         memset(cpubitmap,0,sizeof(cpubitmap));
  57
  58         FILE *f = fopen("/proc/cpuinfo","r");
  59         if (!f)
  60                 return -1;
  61
  62         char buf[8192];
  63         while (fgets(buf,sizeof(buf),f)) {
  64                 // we don't like newlines
  65                 for (char *p = buf;*p;++p) {
  66                         if (*p == '\n') {
  67                                 *p = 0;
  68                                 break;
  69                         }
  70                 }
  71                 // split ':'
  72                 char *v = 0;
  73                 for (char *p = buf;*p;++p) {
  74                         if (*p == ':') {
  75                                 *p = 0;
  76                                 v = p + 1;
  77                                 break;
  78                         }
  79                 }
  80                 // key padding
  81                 size_t kl = strlen(buf);
  82                 while (kl > 0 && (buf[kl - 1] == '\t' || buf[kl - 1] == ' ')) {
  83                         --kl;
  84                         buf[kl] = 0;
  85                 }
  86                 // space before value
  87                 if (v) {
  88                         while (*v && (*v == ' ' || *v == '\t'))
  89                                 ++v;
  90                 }
  91                 // check what we need
  92                 if (strcasecmp(buf,"processor") == 0 && v) {
  93                         char *endp = 0;
  94                         long n = strtol(v,&endp,10);
  95                         if (endp && endp > v && n >= 0 && n < sizeof(cpubitmap) * 8)
  96                                 cpubitmap[n / 8] |= 1 << (n % 8);
  97                 }
  98         }
  99
 100         fclose(f);
 101
 102         // count bits in bitmap
 103         int ncpu = 0;
 104         for (size_t n = 0;n < sizeof(cpubitmap) * 8;++n)
 105                 if (cpubitmap[n / 8] & (1 << (n % 8)))
 106                         ++ncpu;
 107
 108         return ncpu;
 109 }
 110 #endif
 111
 112 int cpucount(void)
 113 {
 114         int ncpu;
 115 #ifdef _SC_NPROCESSORS_ONLN
 116         ncpu = (int)sysconf(_SC_NPROCESSORS_ONLN);
 117         if (ncpu > 0)
 118                 return ncpu;
 119 #endif
 120 #ifdef __linux__
 121         // try parsing /proc/cpuinfo
 122         ncpu = parsecpuinfo();
 123         if (ncpu > 0)
 124                 return ncpu;
 125 #endif
 126 #ifdef BSD
 127         const int ctlname[2] = {CTL_HW,HW_NCPU};
 128         size_t ctllen = sizeof(ncpu);
 129         if (sysctl(ctlname,2,&ncpu,&ctllen,0,0) < 0)
 130                 ncpu = -1;
 131         if (ncpu > 0)
 132                 return ncpu;
 133 #endif
 134         return -1;
 135 }