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- #include <errno.h>
- #include <unistd.h>
- #include <string.h>
- #include <sys/stat.h>
- #include <dirent.h>
- static int __check_dir_for_tty_match(char * dirname, struct stat *st, char *buf, size_t buflen)
- {
- DIR *fp;
- int len;
- struct stat dst;
- struct dirent *d;
- fp = opendir(dirname);
- if (fp == NULL)
- return errno;
- strncpy(buf, dirname, buflen);
- strncat(buf, "/", buflen);
- len = strlen(dirname) + 1;
- while ((d = readdir(fp)) != 0) {
- strncpy(buf+len, d->d_name, buflen);
- buf[buflen]='\0';
- if (stat(buf, &dst) == 0 && st->st_dev == dst.st_dev
- && st->st_ino == dst.st_ino)
- {
- closedir(fp);
- return 0;
- }
- }
- closedir(fp);
- return ENOTTY;
- }
- /* This is a fairly slow approach. We do a linear search through some
- * directories looking for a match. Yes this is lame. But it should
- * work, should be small, and will return names that match what is on
- * disk. Another approach we could use would be to use the info in
- * /proc/self/fd, but that is even more lame since it requires /proc */
- char *ttyname(int fd)
- {
- static char name[NAME_MAX];
- ttyname_r(fd, name, NAME_MAX);
- return(name);
- }
- int ttyname_r(int fd, char *buf, size_t buflen)
- {
- int noerr;
- struct stat st;
- noerr = errno;
- if (buf==NULL) {
- noerr = EINVAL;
- goto cool_found_it;
- }
- /* Make sure we have enough space to return "/dev/pts/0" */
- if (buflen < 10) {
- noerr = ERANGE;
- goto cool_found_it;
- }
- if (!isatty (fd)) {
- noerr = ENOTTY;
- goto cool_found_it;
- }
- if (fstat(fd, &st) < 0)
- return errno;
- if (!isatty(fd)) {
- noerr = ENOTTY;
- goto cool_found_it;
- }
- /* Lets try /dev/vc first (be devfs compatible) */
- if ( (noerr=__check_dir_for_tty_match("/dev/vc", &st, buf, buflen)) == 0)
- goto cool_found_it;
- /* Lets try /dev/tts next (be devfs compatible) */
- if ( (noerr=__check_dir_for_tty_match("/dev/tts", &st, buf, buflen)) == 0)
- goto cool_found_it;
- /* Lets try /dev/pts next */
- if ( (noerr=__check_dir_for_tty_match("/dev/pts", &st, buf, buflen)) == 0)
- goto cool_found_it;
- /* Lets try walking through /dev last */
- if ( (noerr=__check_dir_for_tty_match("/dev", &st, buf, buflen)) == 0)
- goto cool_found_it;
- cool_found_it:
- __set_errno(noerr);
- return noerr;
- }
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