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Linux C代码实现读取配置文件示例

最近在看hostapd,该程序使用了conf配置文件,本文参考hostapd代码抽取出读取配置文件的示例,由于配置选项和业务密切相关,实际使用中仍需要做修改。

下面是代码示例:

/**
读配置文件示例
注:配置文件必须为unix格式,即\n结尾

*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <stdint.h>

// 结构体
struct hostapd_config
{
    char iface[16];
    uint16_t beacon_int;

    uint8_t channel;

    char country[3]; /* first two octets: country code as described in
              * ISO/IEC 3166-1. Third octet:
              * ' ' (ascii 32): all environments
              * 'O': Outdoor environemnt only
              * 'I': Indoor environment only
              */
};

// 默认值
struct hostapd_config * config_defaults(void)
{
    struct hostapd_config *conf = NULL;

    conf = (struct hostapd_config *)calloc(1, sizeof(*conf));
    if (conf == NULL)
    {
        return NULL;
    }

    // set default value
    conf->beacon_int = 100;
    conf->channel = 1;

    return conf;
}

// 根据读取到的信息填充结构体
static int config_defaults(struct hostapd_config *conf, const char *buf, char *pos, int line)
{
    if (strcmp(buf, "interface") == 0)
    {
        strncpy(conf->iface, pos, sizeof(conf->iface));
    }
    else if (strcmp(buf, "channel") == 0)
    {
        int val = atoi(pos);
        conf->channel = val;
    }
    else if (strcmp(buf, "beacon_int") == 0)
    {
        int val = atoi(pos);
        conf->beacon_int = val;
    }
    else if (strcmp(buf, "country_code") == 0)
    {
        memcpy(conf->country, pos, 2);
        conf->country[2] = ' ';
    }
    // more ...
    return 0;
}

//////////////////////////////////////
// 读配置文件
struct hostapd_config* config_read(const char *fname)
{
    struct hostapd_config *conf = NULL;
    FILE *f = NULL;
    char buf[1024] = {0};
    char *pos = NULL;
    int line = 0;
    int errors = 0;
    
    f = fopen(fname, "r");
    if (f == NULL)
    {
        printf("Could not open configuration file '%s' for reading.\n", fname);
        return NULL;
    }
    
    conf = config_defaults();
    if (conf == NULL)
    {
        fclose(f);
        return NULL;
    }
    
    while (fgets(buf, sizeof(buf), f))
    {
        line++;

        if (buf[0] == '#')
            continue;
        pos = buf;
        while (*pos != '\0')
        {
            if (*pos == '\n')
            {
                *pos = '\0';
                break;
            }
            pos++;
        }
        if (buf[0] == '\0')
            continue;

        pos = strchr(buf, '=');
        if (pos == NULL) {
            printf("Line %d: invalid line '%s'\n", line, buf);
            errors++;
            continue;
        }
        *pos = '\0';
        pos++;
        errors += config_defaults(conf, buf, pos, line);
    }

    fclose(f);

    return conf;
}

/////////////////////////////////////

int main(int argc, char *argv[])
{
    const char* conf_file = "foo.conf";

    if (argc == 2)
    {
        conf_file = argv[1];
    }

    struct hostapd_config *conf = NULL;
    
    conf = config_read(conf_file);
    if (conf == NULL)
    {
        printf("failed to read file: %s\n", conf_file);
        return -1;
    }
    printf("%d %s %s\n", conf->channel, conf->country, conf->iface);

    return 0;
}

李迟 2016.8.21 周日

 

本文固定链接: http://www.latelee.org/my-library/linux-c-read-config-file-example.html

如无特别说明,迟思堂工作室文章均为原创,转载请注明: Linux C代码实现读取配置文件示例 | 迟思堂工作室

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