wmcpuload/src/cpu_linux.c

   1 /*
   2  * cpu_linux.c - module to get cpu usage, for GNU/Linux
   3  *
   4  * Copyright (C) 2001, 2002 Seiichi SATO <ssato@sh.rim.or.jp>
   5  *
   6  * licensed under the GPL
   7  */
   8
   9 #ifdef HAVE_CONFIG_H
  10 #include "config.h"
  11 #endif
  12
  13 #include <stdio.h>
  14 #include <unistd.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include "cpu.h"
  18
  19 #include <dirent.h>
  20 #include <sys/types.h>
  21 #include <sys/stat.h>
  22 #include <linux/limits.h>
  23
  24 #ifdef USE_SMP
  25 #include <linux/threads.h>
  26 #endif
  27
  28 static void set_pidlist_from_namelist(int names, char **name_list);
  29 static int get_cpuusage_bypid(pid_t pid);
  30
  31 static int *pid_list;
  32 static int pids;
  33
  34 void cpu_init(void)
  35 {
  36     /*  You don't need initialization under GNU/Linux */
  37     return;
  38 }
  39
  40 /* returns current cpu usage in percent */
  41 int
  42 cpu_get_usage(cpu_options *opts)
  43 {
  44     static int pre_used, pre_total;
  45     static int pre_ig_used;
  46     int usage;
  47     int cpu, nice, system, idle;
  48     int used = 0, total = 0;
  49     int ig_used = 0;
  50     int i;
  51
  52     FILE *fp;
  53     if (!(fp = fopen("/proc/stat", "r"))) {
  54         perror("can't open /proc/stat");
  55         exit(1);
  56     }
  57
  58     fscanf(fp, "%*s %d %d %d %d", &cpu, &nice, &system, &idle);
  59
  60 #ifdef USE_SMP
  61     if (opts->cpu_number >= 0) {
  62         char cpu_name[20];
  63         if (opts->cpu_number > NR_CPUS - 1) {
  64             fprintf (stderr, "MAX CPU number that can be running in SMP is %d\n", NR_CPUS - 1);
  65             exit(1);
  66         }
  67
  68         for (i = 0; i <= opts->cpu_number; i++) {
  69             fscanf(fp, "%s %d %d %d %d", cpu_name, &cpu, &nice, &system, &idle);
  70             if (strncmp(cpu_name, "cpu", 3)){
  71                 fprintf (stderr, "can't find cpu%d!\n", opts->cpu_number);
  72                 exit (1);
  73             }
  74         }
  75     }
  76 #endif /* USE_SMP */
  77
  78     fclose(fp);
  79     used = cpu + system;
  80     if (!opts->ignore_nice)
  81         used += nice;
  82     total = cpu + nice + system + idle;
  83
  84     /* get CPU usage of processes which specified by name with '-p' option */
  85     if (opts->ignore_procs) {
  86         pids = 0;
  87         if (!(pid_list = malloc(sizeof(pid_t)))) {
  88             perror("malloc");
  89             exit(1);
  90         }
  91         set_pidlist_from_namelist(opts->ignore_procs, opts->ignore_proc_list);
  92         for (i = 0; i < pids; i++)
  93             ig_used += get_cpuusage_bypid(pid_list[i]);
  94         free(pid_list);
  95     }
  96
  97     /* calc CPU usage */
  98     if ((pre_total == 0) || !(total - pre_total > 0)) {
  99         usage = 0;
 100     } else  if (ig_used - pre_ig_used > 0) {
 101         usage = (100 * (double)(used - pre_used - ig_used + pre_ig_used)) /
 102                 (double)(total - pre_total);
 103     } else {
 104         usage = (100 * (double)(used - pre_used)) / (double)(total - pre_total);
 105     }
 106
 107     /* save current values for next calculation */
 108     pre_ig_used = ig_used;
 109     pre_used = used;
 110     pre_total = total;
 111
 112     return usage;
 113 }
 114
 115 /* set pid list table from command names */
 116 static void
 117 set_pidlist_from_namelist(int names, char **name_list)
 118 {
 119     DIR *dir;
 120     struct dirent *de;
 121     FILE *fp;
 122     char path[PATH_MAX + 1];
 123     char comm[COMM_LEN];
 124     pid_t pid;
 125     int i;
 126
 127     if (!(dir = opendir("/proc"))) {
 128         perror("can't open /proc");
 129         exit(1);
 130     }
 131
 132     /* search specified process from all processes */
 133     chdir("/proc");
 134     while ((de = readdir(dir)) != NULL) {
 135         if ((de->d_name[0] != '.') &&
 136             ((de->d_name[0] >= '0') && (de->d_name[0] <= '9'))) {
 137             pid = (pid_t) atoi(de->d_name);
 138             sprintf(path, "%d/stat", pid);
 139             if ((fp = fopen(path, "r")) != NULL) {
 140                 fscanf(fp, "%*d (%[^)]", comm);
 141                 for (i = 0; i < names; i++) {
 142                     if (strcmp(comm, name_list[i]) == 0) {
 143                         /* add process id to list */
 144                         pids++;
 145                         if (!(pid_list=realloc(pid_list, pids*sizeof(pid_t)))){
 146                             perror("realloc() failed");
 147                             exit(1);
 148                         }
 149                         pid_list[pids - 1] = pid;
 150                     }
 151                 }
 152                 fclose(fp);
 153             }
 154         }
 155     }
 156     closedir(dir);
 157 }
 158
 159 static int
 160 get_cpuusage_bypid(pid_t pid)
 161 {
 162     FILE *fp;
 163     char path[PATH_MAX];
 164     int utime = 0, stime = 0;
 165     int ret = 0;
 166
 167     sprintf(path, "/proc/%d/stat", pid);
 168     if ((fp = fopen(path, "r")) != NULL) {
 169         fscanf(fp, "%*d %*s %*s %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %d %d ",
 170                &utime, &stime);
 171         fclose(fp);
 172     }
 173
 174     ret = utime + stime;
 175     return ret;
 176 }