cpucount.c

   1
   2 #ifndef BSD
   3 #  ifndef __linux__
   4 // FreeBSD
   5 #    ifdef __FreeBSD__
   6 #      undef BSD
   7 #      define BSD
   8 #    endif
   9 // OpenBSD
  10 #    ifdef __OpenBSD__
  11 #      undef BSD
  12 #      define BSD
  13 #    endif
  14 // NetBSD
  15 #    ifdef __NetBSD__
  16 #      undef BSD
  17 #      define BSD
  18 #    endif
  19 // DragonFly
  20 #    ifdef __DragonFly__
  21 #      undef BSD
  22 #      define BSD
  23 #    endif
  24 #  endif // __linux__
  25 // sys/param.h may have its own define
  26 #  ifdef BSD
  27 #    undef BSD
  28 #    include <sys/param.h>
  29 #    define SYS_PARAM_INCLUDED
  30 #    ifndef BSD
  31 #      define BSD
  32 #    endif
  33 #  endif
  34 #endif // BSD
  35
  36 #ifdef BSD
  37 #  ifndef SYS_PARAM_INCLUDED
  38 #    include <sys/param.h>
  39 #  endif
  40 #  include <sys/sysctl.h>
  41 #endif
  42
  43 #include <unistd.h>
  44 #include <string.h>
  45 #include <stdio.h>
  46
  47 #ifdef __linux__
  48 #include <stdio.h>
  49 #include <stdlib.h>
  50 #include <strings.h>
  51 static int parsecpuinfo()
  52 {
  53         unsigned char cpubitmap[128];
  54
  55         memset(cpubitmap,0,sizeof(cpubitmap));
  56
  57         FILE *f = fopen("/proc/cpuinfo","r");
  58         if (!f)
  59                 return -1;
  60
  61         char buf[8192];
  62         while (fgets(buf,sizeof(buf),f)) {
  63                 // we don't like newlines
  64                 for (char *p = buf;*p;++p) {
  65                         if (*p == '\n') {
  66                                 *p = 0;
  67                                 break;
  68                         }
  69                 }
  70                 // split ':'
  71                 char *v = 0;
  72                 for (char *p = buf;*p;++p) {
  73                         if (*p == ':') {
  74                                 *p = 0;
  75                                 v = p + 1;
  76                                 break;
  77                         }
  78                 }
  79                 // key padding
  80                 size_t kl = strlen(buf);
  81                 while (kl > 0 && (buf[kl - 1] == '\t' || buf[kl - 1] == ' ')) {
  82                         --kl;
  83                         buf[kl] = 0;
  84                 }
  85                 // space before value
  86                 if (v) {
  87                         while (*v && (*v == ' ' || *v == '\t'))
  88                                 ++v;
  89                 }
  90                 // check what we need
  91                 if (strcasecmp(buf,"processor") == 0 && v) {
  92                         char *endp = 0;
  93                         long n = strtol(v,&endp,10);
  94                         if (endp && endp > v && n >= 0 && n < sizeof(cpubitmap) * 8)
  95                                 cpubitmap[n / 8] |= 1 << (n % 8);
  96                 }
  97         }
  98
  99         fclose(f);
 100
 101         // count bits in bitmap
 102         int ncpu = 0;
 103         for (size_t n = 0;n < sizeof(cpubitmap) * 8;++n)
 104                 if (cpubitmap[n / 8] & (1 << (n % 8)))
 105                         ++ncpu;
 106
 107         return ncpu;
 108 }
 109 #endif
 110
 111 #include "cpucount.h"
 112
 113 int cpucount()
 114 {
 115         int ncpu;
 116 #ifdef _SC_NPROCESSORS_ONLN
 117         ncpu = (int)sysconf(_SC_NPROCESSORS_ONLN);
 118         if (ncpu > 0)
 119                 return ncpu;
 120 #endif
 121 #ifdef __linux__
 122         // try parsing /proc/cpuinfo
 123         ncpu = parsecpuinfo();
 124         if (ncpu > 0)
 125                 return ncpu;
 126 #endif
 127 #ifdef BSD
 128         const int ctlname[2] = {CTL_HW,HW_NCPU};
 129         size_t ctllen = sizeof(ncpu);
 130         if (sysctl(ctlname,2,&ncpu,&ctllen,0,0) < 0)
 131                 ncpu = -1;
 132         if (ncpu > 0)
 133                 return ncpu;
 134 #endif
 135         return -1;
 136 }