linux C 简易版iostat

Linux下用C语言获取IO信息 只获取iostat的CPU信息

代码如下

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <errno.h>
#include <sys/param.h>
#include <linux/major.h>


struct cpu_info {
    unsigned long long user;
    unsigned long long system;
    unsigned long long idle;
    unsigned long long iowait;
};

void mini_iostat()
{
    int linux_ver = 6;
    FILE* fp=NULL;
    const char* scan_fmt = NULL;
    struct cpu_info info;
    double total;
    char buffer[1024];
    fp = fopen("/proc/diskstats", "r");
    if (fp) {
        linux_ver = 6;
    }
    else {
        fp = fopen("/proc/partitions", "r");
        if (fp)
            linux_ver = 4;
    }
    if (fp)fclose(fp);

    switch (linux_ver) {
    case 4:
        scan_fmt = "%4d %4d %*d %*s %u %u %llu %u %u %u %llu %u %*u %u %u";
        break;
    case 6:
        scan_fmt = "%4d %4d %*s %u %u %llu %u %u %u %llu %u %*u %u %u";
        break;
    }

    fp = fopen("/proc/stat", "r");
    while (fgets(buffer, sizeof(buffer), fp)) {
        if (!strncmp(buffer, "cpu ", 4)) {
            int items;
            unsigned long long nice, irq, softirq;

            items = sscanf(buffer,
                "cpu %llu %llu %llu %llu %llu %llu %llu",
                &info.user, &nice,
                &info.system,
                &info.idle,
                &info.iowait,
                &irq, &softirq);

            info.user += nice;
            if (items == 4)
                info.iowait = 0;
            if (items == 7)
                info.system += irq + softirq;

        }
    }
    fclose(fp);

    total = (info.user + info.system + info.idle + info.iowait) / 100.0;
    printf("user=%3.0f system=%3.0f ", info.user / total, info.system / total);
    if (linux_ver == 6)
        printf("iowait=%3.0f ", info.iowait / total);
    printf("idle=%3.0f\n", info.idle / total);
}
int main(int argc, char** argv)
{
    mini_iostat();
    return 0;
}