linux系统信息获取和上报 linux内存查看及释放 /proc/meminfo分析

通过调用shell命令获取系统信息，如cpu个数，cpu/内存磁盘使用情况，网络信息等。

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define CMD_BUF_SIZE    256 

typedef float (*func_trans)(char *buf, int buf_size);
static float trans_cpu_avg_rate(char *buf, int buf_size);
static float trans_cpu_now_rate(char *buf, int buf_size);
static float trans_mem_rate(char *buf, int buf_size);

static int exec_cmd(char *buf, int buf_size, char *cmd)
{
    if(NULL == cmd || NULL == buf || buf_size <= 0){
        return -1;
    }

    FILE *f = NULL;
    int len = 0;

    f= popen(cmd, "r");
    if(NULL == f){
        return -1;
    }

//    memset(buf, '\0', buf_size);
    if(NULL == fgets(buf, buf_size, f)){
        pclose(f);
        return -1;
    }

    pclose(f);

    len = strlen(buf);
    if(len > 0 && (buf[len-1] == '\n')){
        buf[len-1] = '\0';
        len --;
    }

    return len;
}

struct st_cmd_gw{
    char *item;
    char format;
    char *cmd;
    func_trans trans;
    char *factor;
} cmd_gw[] = {
    {"ip1", 's', "ifconfig eth0 | awk '/inet /{ print $2; }' | cut -d : -f 2", NULL, NULL},
    {"wlp1s0", 's', "ifconfig wlp1s0 | awk '/inet /{ print $2; }' | cut -d : -f 2", NULL, NULL},
    {"pppoe", 's', "ifconfig ppp0 | awk '/inet /{ print $2; }' | cut -d : -f 2", NULL, NULL},    
    {"time_now", 's', "date '+%Y-%m-\%d %H:%M:\%S'", NULL, NULL},
    {"time_up", 's', "uptime | awk '{ print $3; }' | cut -d ',' -f1", NULL, NULL},
    {"cpu_avg_rate", 'f', "cat /proc/loadavg | cut -d ' ' -f 1", trans_cpu_avg_rate, "100*\%f/4"},
    {"cpu_now_rate", 'f', "top -b -n 1|grep Cpu|awk '{print $8; }' ", trans_cpu_now_rate, "100.00-\%f"},
    {"cpu_usr_now_rate", 'f', "top -b -n 1|grep Cpu|awk '{print $2; }'", NULL, NULL},
    {"disk_rate", 'f', "df -h | grep '/dev/root' | awk '{print $5}'", NULL, NULL},
    {"disk_use_f", 'f', "df -h | grep '/dev/root' | awk '{print $3}'", NULL, NULL},
    {"disk_avail_f", 'f', "df -h | grep '/dev/root' | awk '{print $4}'", NULL, NULL},
    {"disk_use_s", 's', "df -h | grep '/dev/root' | awk '{print $3}'", NULL, NULL},
    {"disk_avail_s", 's', "df -h | grep '/dev/root' | awk '{print $4}'", NULL, NULL},
    {"ram_rate", 'f', "cat /proc/meminfo | awk '/MemTotal/{print $2}'", trans_mem_rate, NULL},
    {"ram_all", 'f', "cat /proc/meminfo | awk '/MemTotal/{print $2}'", NULL, NULL},
    {"ram_free", 'f', "cat /proc/meminfo | awk '/MemFree/{print $2}'", NULL, NULL},
    {"cpu_num", 's', "cat /proc/cpuinfo | grep \"processor\" | wc -l | awk '{print $1}'", NULL, NULL}
};

// out: output the result of the string type
// f: output the result of the float type
int out_gw(char *out, int out_len, const char *in, float *f)
{
    if(NULL == in || NULL == out || out_len <= 0){
        return -1;
    }

    int i = 0;
    int len = strlen(in);
    int count = sizeof(cmd_gw)/sizeof(cmd_gw[0]);

    for(; i < count; i++){
        if(!strncasecmp(in, cmd_gw[i].item, len)){
            break;            
        }    
    }

    if(i >count){
        return -1;
    }

    int ret = exec_cmd(out, out_len, cmd_gw[i].cmd);
    if(ret <= 0){
        return -1;
    }
    
    *f = 0.0;
    if('f' == cmd_gw[i].format){
        if(cmd_gw[i].trans){
            *f = (cmd_gw[i].trans)(out, out_len);    
        } else {
            *f = atof(out);
        }
    }
    
    return cmd_gw[i].format;
}

static float trans_cpu_avg_rate(char *buf, int buf_size)
{
    return 100 * atof(buf) / 4;
}

static float trans_cpu_now_rate(char *buf, int buf_size)
{
    return 100.00 - atof(buf);
}

static float trans_mem_rate(char *buf, int buf_size)
{
    float f = 0.0;
    char out_free[CMD_BUF_SIZE] = {'\0'};
    int ret_free = out_gw(out_free, sizeof(out_free), "mem_free", &f);

    if('f' != (char)ret_free){
        return -1;
    }

    return 100.00 - 100.00 * atof(out_free) / atof(buf);
}

参考：

1. linux内存查看及释放

2. /proc/meminfo分析