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最新推荐文章于 2025-01-09 16:37:03 发布

silentpebble

最新推荐文章于 2025-01-09 16:37:03 发布

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分类专栏： test code

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/*
 *[silent]#gcc readlink.c -o readlink
 *[silent]#./readlink /usr/bin/vi
 */

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <linux/limits.h>
#include <sys/stat.h>

int is_slink(char *file)
{
        struct stat file_stat= {0};

        if (lstat(file, &file_stat) == -1)
                return 0;

        return S_ISLNK(file_stat.st_mode) ? 1 : 0;
}

char *get_realpath(const char *file, char *realpath)
{
#define MAX_LINK_DEPTH 8
        int depth = 0;
        char buf[PATH_MAX]  = {0};

        if (realpath == NULL || file == NULL)
                return NULL;

        snprintf(buf, PATH_MAX, "%s", file);
        snprintf(realpath, PATH_MAX, "%s", file);

        for (; depth <= MAX_LINK_DEPTH; ) {
                if (is_slink(buf)) {
                        memset(realpath, 0, PATH_MAX);

                        readlink(buf, realpath, PATH_MAX);

                        memset(buf, 0, PATH_MAX);
                        snprintf(buf, PATH_MAX, "%s", realpath);

                        continue;
                }
                break;
        }

        return realpath;

}

int main(int argc, char **argv)
{
        char *file = argv[1];
        char realpath[PATH_MAX] = {0};
        get_realpath(file, realpath);
        printf("real path = %s\n", realpath);
}