C语言的readlink
read value of a symbolic link。
ssize_t readlink(const char *path, char *buf, size_t bufsiz);
readlink() places the contents of the symbolic link path in the buffer buf, which has size bufsiz. readlink() does not append a null byte to buf. 把path所指的符号连接中对应的文件路径放到buf中，最多bufsiz个字节。
示例
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "sys/types.h"
#include <sys/stat.h>
#include <fcntl.h>
//#include <>
int get_pathname_from_fd(int fd, char pathname[], int n)
{
char buf[1024];
pid_t pid;
bzero(buf, 1024);
pid = getpid();
snprintf(buf, 1024, "/proc/%i/fd/%i", pid, fd);
return readlink(buf, pathname, n);
}
int main(void)
{
int fd;
char pathname[4096];
bzero(pathname, 4096);
fd = open("/tmp/foo", O_CREAT|O_RDONLY);
get_pathname_from_fd(fd, pathname, 4096);
printf("fd=%d; pathname=%s\n", fd, pathname);
return 0;
}