Add print_cpu_usage

i3status.c

@@ -226,6 +226,11 @@ int main(int argc, char *argv[]) {
                 CFG_STR("format", "%5min %10min %15min", CFGF_NONE),
                 CFG_END()
         };
+        
+        cfg_opt_t usage_opts[] = {
+                CFG_STR("format", "%usage", CFGF_NONE),
+                CFG_END()
+        };
 
         cfg_opt_t temp_opts[] = {
                 CFG_STR("format", "%degrees C", CFGF_NONE),
@@ -260,6 +265,7 @@ int main(int argc, char *argv[]) {
                 CFG_SEC("time", time_opts, CFGF_NONE),
                 CFG_SEC("ddate", ddate_opts, CFGF_NONE),
                 CFG_SEC("load", load_opts, CFGF_NONE),
+                CFG_SEC("cpu_usage", usage_opts, CFGF_NONE),
                 CFG_END()
         };
 
@@ -370,6 +376,9 @@ int main(int argc, char *argv[]) {
 
                         CASE_SEC_TITLE("cpu_temperature")
                                 print_cpu_temperature_info(atoi(title), cfg_getstr(sec, "path"), cfg_getstr(sec, "format"));
+                        
+                        CASE_SEC("cpu_usage")
+                                print_cpu_usage(cfg_getstr(sec, "format"));
                 }
                 printf("\n");
                 fflush(stdout);

include/i3status.h

@@ -68,6 +68,7 @@ const char *get_ip_addr();
 void print_wireless_info(const char *interface, const char *format_up, const char *format_down);
 void print_run_watch(const char *title, const char *pidfile, const char *format);
 void print_cpu_temperature_info(int zone, const char *path, const char *format);
+void print_cpu_usage(const char *format);
 void print_eth_info(const char *interface, const char *format_up, const char *format_down);
 void print_load();
 void print_volume(const char *fmt, const char *device, const char *mixer, int mixer_idx);

src/print_cpu_usage.c

@@ -0,0 +1,50 @@
+// vim:sw=8:sts=8:ts=8:expandtab
+#include <stdlib.h>
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "i3status.h"
+
+static int prev_total = 0;
+static int prev_idle  = 0;
+
+/*
+ * Reads the CPU utilization from /proc/stat and returns the usage as a
+ * percentage.
+ *
+ */
+void print_cpu_usage(const char *format) { 
+        const char *walk;
+        char buf[1024];
+        int curr_user, curr_nice, curr_system, curr_idle, curr_total;
+        int diff_idle, diff_total, diff_usage;
+
+#if defined(LINUX)
+        static char statpath[512];
+        strcpy(statpath, "/proc/stat");
+        if (!slurp(statpath, buf, sizeof(buf)))
+                die("could not read %s\n", statpath);
+
+        if (sscanf(buf, "cpu %d %d %d %d", &curr_user, &curr_nice, &curr_system, &curr_idle) != 4)
+                die("could not read cpu utilization\n");
+
+        curr_total = curr_user + curr_nice + curr_system + curr_idle;
+        diff_idle  = curr_idle - prev_idle;
+        diff_total = curr_total - prev_total;
+        diff_usage = (1000 * (diff_total - diff_idle)/diff_total + 5)/10;
+        prev_total = curr_total;
+        prev_idle  = curr_idle;
+#endif
+        for (walk = format; *walk != '\0'; walk++) {
+                if (*walk != '%') {
+                        putchar(*walk);
+                        continue;
+                }
+
+                if (strncmp(walk+1, "usage", strlen("usage")) == 0) {
+                        printf("%02d%%", diff_usage);
+                        walk += strlen("usage");
+                }
+        }
+}