fix errno value when fdopendir is given an invalid file descriptor

[musl] / src / dirent / fdopendir.c

#include <dirent.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <limits.h>
#include "__dirent.h"

DIR *fdopendir(int fd)
{
        DIR *dir;
        struct stat st;

        if (fstat(fd, &st) < 0) {
                return 0;
        }
        if (!S_ISDIR(st.st_mode)) {
                errno = ENOTDIR;
                return 0;
        }
        if (!(dir = calloc(1, sizeof *dir))) {
                return 0;
        }

        fcntl(fd, F_SETFD, FD_CLOEXEC);
        dir->fd = fd;
        return dir;
}