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 #include <yajl/yajl_version.h>
   8
   9 #if defined(__FreeBSD__) || defined(__OpenBSD__)
  10 #include <sys/param.h>
  11 #include <sys/types.h>
  12 #include <sys/sysctl.h>
  13 #include <sys/dkstat.h>
  14 #endif
  15
  16 #if defined(__DragonFly__)
  17 #include <sys/param.h>
  18 #include <sys/types.h>
  19 #include <sys/sysctl.h>
  20 #include <sys/resource.h>
  21 #endif
  22
  23 #include "i3status.h"
  24
  25 static int prev_total = 0;
  26 static int prev_idle  = 0;
  27
  28 /*
  29  * Reads the CPU utilization from /proc/stat and returns the usage as a
  30  * percentage.
  31  *
  32  */
  33 void print_cpu_usage(yajl_gen json_gen, char *buffer, const char *format) {
  34         const char *walk;
  35         char *outwalk = buffer;
  36         char buf[1024];
  37         int curr_user = 0, curr_nice = 0, curr_system = 0, curr_idle = 0, curr_total;
  38         int diff_idle, diff_total, diff_usage;
  39
  40 #if defined(LINUX)
  41         static char statpath[512];
  42         strcpy(statpath, "/proc/stat");
  43         if (!slurp(statpath, buf, sizeof(buf)) ||
  44             sscanf(buf, "cpu %d %d %d %d", &curr_user, &curr_nice, &curr_system, &curr_idle) != 4)
  45                 goto error;
  46
  47         curr_total = curr_user + curr_nice + curr_system + curr_idle;
  48         diff_idle  = curr_idle - prev_idle;
  49         diff_total = curr_total - prev_total;
  50         diff_usage = (diff_total ? (1000 * (diff_total - diff_idle)/diff_total + 5)/10 : 0);
  51         prev_total = curr_total;
  52         prev_idle  = curr_idle;
  53 #elif defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
  54
  55 #if defined(__FreeBSD__) || defined(__DragonFly__)
  56         size_t size;
  57         long cp_time[CPUSTATES];
  58         size = sizeof cp_time;
  59         if (sysctlbyname("kern.cp_time", &cp_time, &size, NULL, 0) < 0)
  60                 goto error;
  61 #else
  62         /* This information is taken from the boot cpu, any other cpus are currently ignored. */
  63         long cp_time[CPUSTATES];
  64         int mib[2];
  65         size_t size = sizeof(cp_time);
  66
  67         mib[0] = CTL_KERN;
  68         mib[1] = KERN_CPTIME;
  69
  70         if (sysctl(mib, 2, cp_time, &size, NULL, 0))
  71                 goto error;
  72 #endif
  73
  74         curr_user = cp_time[CP_USER];
  75         curr_nice = cp_time[CP_NICE];
  76         curr_system = cp_time[CP_SYS];
  77         curr_idle = cp_time[CP_IDLE];
  78         curr_total = curr_user + curr_nice + curr_system + curr_idle;
  79         diff_idle  = curr_idle - prev_idle;
  80         diff_total = curr_total - prev_total;
  81         diff_usage = (diff_total ? (1000 * (diff_total - diff_idle)/diff_total + 5)/10 : 0);
  82         prev_total = curr_total;
  83         prev_idle  = curr_idle;
  84 #else
  85         goto error;
  86 #endif
  87         for (walk = format; *walk != '\0'; walk++) {
  88                 if (*walk != '%') {
  89                         *(outwalk++) = *walk;
  90                         continue;
  91                 }
  92
  93                 if (strncmp(walk+1, "usage", strlen("usage")) == 0) {
  94                         outwalk += sprintf(outwalk, "%02d%%", diff_usage);
  95                         walk += strlen("usage");
  96                 }
  97         }
  98
  99         OUTPUT_FULL_TEXT(buffer);
 100         return;
 101 error:
 102         OUTPUT_FULL_TEXT("cant read cpu usage");
 103         (void)fputs("i3status: Cannot read CPU usage\n", stderr);
 104 }