| /* Copyright (C) 1991-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <errno.h> |
| #include <limits.h> |
| #include <stddef.h> |
| #include <dirent.h> |
| #include <sys/types.h> |
| #include <sys/stat.h> |
| #include <termios.h> |
| #include <unistd.h> |
| #include <string.h> |
| #include <stdlib.h> |
| |
| #include <_itoa.h> |
| |
| #include "ttyname.h" |
| |
| static int getttyname_r (char *buf, size_t buflen, |
| const struct stat64 *mytty, int save, |
| int *dostat); |
| |
| static int |
| attribute_compat_text_section |
| getttyname_r (char *buf, size_t buflen, const struct stat64 *mytty, |
| int save, int *dostat) |
| { |
| struct stat64 st; |
| DIR *dirstream; |
| struct dirent64 *d; |
| size_t devlen = strlen (buf); |
| |
| dirstream = __opendir (buf); |
| if (dirstream == NULL) |
| { |
| *dostat = -1; |
| return errno; |
| } |
| |
| while ((d = __readdir64 (dirstream)) != NULL) |
| if ((d->d_fileno == mytty->st_ino || *dostat) |
| && strcmp (d->d_name, "stdin") |
| && strcmp (d->d_name, "stdout") |
| && strcmp (d->d_name, "stderr")) |
| { |
| char *cp; |
| size_t needed = _D_EXACT_NAMLEN (d) + 1; |
| |
| if (needed > buflen) |
| { |
| *dostat = -1; |
| (void) __closedir (dirstream); |
| __set_errno (ERANGE); |
| return ERANGE; |
| } |
| |
| cp = __stpncpy (buf + devlen, d->d_name, needed); |
| cp[0] = '\0'; |
| |
| if (__xstat64 (_STAT_VER, buf, &st) == 0 |
| && is_mytty (mytty, &st)) |
| { |
| (void) __closedir (dirstream); |
| __set_errno (save); |
| return 0; |
| } |
| } |
| |
| (void) __closedir (dirstream); |
| __set_errno (save); |
| /* It is not clear what to return in this case. `isatty' says FD |
| refers to a TTY but no entry in /dev has this inode. */ |
| return ENOTTY; |
| } |
| |
| /* Store at most BUFLEN character of the pathname of the terminal FD is |
| open on in BUF. Return 0 on success, otherwise an error number. */ |
| int |
| __ttyname_r (int fd, char *buf, size_t buflen) |
| { |
| char procname[30]; |
| struct stat64 st, st1; |
| int dostat = 0; |
| int doispty = 0; |
| int save = errno; |
| |
| /* Test for the absolute minimal size. This makes life easier inside |
| the loop. */ |
| if (!buf) |
| { |
| __set_errno (EINVAL); |
| return EINVAL; |
| } |
| |
| if (buflen < sizeof ("/dev/pts/")) |
| { |
| __set_errno (ERANGE); |
| return ERANGE; |
| } |
| |
| /* isatty check, tcgetattr is used because it sets the correct |
| errno (EBADF resp. ENOTTY) on error. */ |
| struct termios term; |
| if (__glibc_unlikely (__tcgetattr (fd, &term) < 0)) |
| return errno; |
| |
| if (__fxstat64 (_STAT_VER, fd, &st) < 0) |
| return errno; |
| |
| /* We try using the /proc filesystem. */ |
| *_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/"), 10, 0) = '\0'; |
| |
| ssize_t ret = __readlink (procname, buf, buflen - 1); |
| if (__glibc_unlikely (ret == -1 && errno == ENAMETOOLONG)) |
| { |
| __set_errno (ERANGE); |
| return ERANGE; |
| } |
| |
| if (__glibc_likely (ret != -1)) |
| { |
| #define UNREACHABLE_LEN strlen ("(unreachable)") |
| if (ret > UNREACHABLE_LEN |
| && memcmp (buf, "(unreachable)", UNREACHABLE_LEN) == 0) |
| { |
| memmove (buf, buf + UNREACHABLE_LEN, ret - UNREACHABLE_LEN); |
| ret -= UNREACHABLE_LEN; |
| } |
| |
| /* readlink need not terminate the string. */ |
| buf[ret] = '\0'; |
| |
| /* Verify readlink result, fall back on iterating through devices. */ |
| if (buf[0] == '/' |
| && __xstat64 (_STAT_VER, buf, &st1) == 0 |
| && is_mytty (&st, &st1)) |
| return 0; |
| |
| doispty = 1; |
| } |
| |
| /* Prepare the result buffer. */ |
| memcpy (buf, "/dev/pts/", sizeof ("/dev/pts/")); |
| buflen -= sizeof ("/dev/pts/") - 1; |
| |
| if (__xstat64 (_STAT_VER, buf, &st1) == 0 && S_ISDIR (st1.st_mode)) |
| { |
| ret = getttyname_r (buf, buflen, &st, save, |
| &dostat); |
| } |
| else |
| { |
| __set_errno (save); |
| ret = ENOENT; |
| } |
| |
| if (ret && dostat != -1) |
| { |
| buf[sizeof ("/dev/") - 1] = '\0'; |
| buflen += sizeof ("pts/") - 1; |
| ret = getttyname_r (buf, buflen, &st, save, |
| &dostat); |
| } |
| |
| if (ret && dostat != -1) |
| { |
| buf[sizeof ("/dev/") - 1] = '\0'; |
| dostat = 1; |
| ret = getttyname_r (buf, buflen, &st, |
| save, &dostat); |
| } |
| |
| if (ret && doispty && is_pty (&st)) |
| { |
| /* We failed to figure out the TTY's name, but we can at least |
| signal that we did verify that it really is a PTY slave. |
| This happens when we have inherited the file descriptor from |
| a different mount namespace. */ |
| __set_errno (ENODEV); |
| return ENODEV; |
| } |
| |
| return ret; |
| } |
| |
| weak_alias (__ttyname_r, ttyname_r) |