git.sur5r.net Git - i3/i3status/blob - src/print_cpu_usage.c

   1 // vim:sw=8:sts=8:ts=8:expandtab
   2 #include <stdlib.h>
   3 #include <limits.h>
   4 #include <stdio.h>
   5 #include <string.h>
   6 #include <yajl/yajl_gen.h>
   7
   8 #ifdef __FreeBSD__
   9 #include <sys/types.h>
  10 #include <sys/sysctl.h>
  11 #include <sys/dkstat.h>
  12 #endif
  13
  14 #include "i3status.h"
  15
  16 static int prev_total = 0;
  17 static int prev_idle  = 0;
  18
  19 /*
  20  * Reads the CPU utilization from /proc/stat and returns the usage as a
  21  * percentage.
  22  *
  23  */
  24 void print_cpu_usage(yajl_gen json_gen, char *buffer, const char *format) {
  25         const char *walk;
  26         char *outwalk = buffer;
  27         char buf[1024];
  28         int curr_user = 0, curr_nice = 0, curr_system = 0, curr_idle = 0, curr_total;
  29         int diff_idle, diff_total, diff_usage;
  30
  31 #if defined(LINUX)
  32         static char statpath[512];
  33         strcpy(statpath, "/proc/stat");
  34         if (!slurp(statpath, buf, sizeof(buf)) ||
  35             sscanf(buf, "cpu %d %d %d %d", &curr_user, &curr_nice, &curr_system, &curr_idle) != 4)
  36                 goto error;
  37
  38         curr_total = curr_user + curr_nice + curr_system + curr_idle;
  39         diff_idle  = curr_idle - prev_idle;
  40         diff_total = curr_total - prev_total;
  41         diff_usage = (1000 * (diff_total - diff_idle)/diff_total + 5)/10;
  42         prev_total = curr_total;
  43         prev_idle  = curr_idle;
  44 #elif defined(__FreeBSD__)
  45         size_t size;
  46         long cp_time[CPUSTATES];
  47         size = sizeof cp_time;
  48         if (sysctlbyname("kern.cp_time", &cp_time, &size, NULL, 0) < 0)
  49                 goto error;
  50
  51         curr_user = cp_time[CP_USER];
  52         curr_nice = cp_time[CP_NICE];
  53         curr_system = cp_time[CP_SYS];
  54         curr_idle = cp_time[CP_IDLE];
  55         curr_total = curr_user + curr_nice + curr_system + curr_idle;
  56         diff_idle  = curr_idle - prev_idle;
  57         diff_total = curr_total - prev_total;
  58         diff_usage = (1000 * (diff_total - diff_idle)/diff_total + 5)/10;
  59         prev_total = curr_total;
  60         prev_idle  = curr_idle;
  61 #else
  62         goto error;
  63 #endif
  64         for (walk = format; *walk != '\0'; walk++) {
  65                 if (*walk != '%') {
  66                         *(outwalk++) = *walk;
  67                         continue;
  68                 }
  69
  70                 if (strncmp(walk+1, "usage", strlen("usage")) == 0) {
  71                         outwalk += sprintf(outwalk, "%02d%%", diff_usage);
  72                         walk += strlen("usage");
  73                 }
  74         }
  75
  76         OUTPUT_FULL_TEXT(buffer);
  77         return;
  78 error:
  79         (void)fputs("Cannot read usage\n", stderr);
  80 }