1 | /* Copyright (C) 1991-2022 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either |
7 | version 2.1 of the License, or (at your option) any later version. |
8 | |
9 | The GNU C Library is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | Lesser General Public License for more details. |
13 | |
14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library; if not, see |
16 | <https://www.gnu.org/licenses/>. */ |
17 | |
18 | #include <errno.h> |
19 | #include <limits.h> |
20 | #include <stddef.h> |
21 | #include <dirent.h> |
22 | #include <sys/types.h> |
23 | #include <sys/stat.h> |
24 | #include <unistd.h> |
25 | #include <string.h> |
26 | #include <stdlib.h> |
27 | |
28 | char *__ttyname; |
29 | |
30 | static char *getttyname (int fd, dev_t mydev, ino_t myino, |
31 | int save, int *dostat); |
32 | |
33 | |
34 | libc_freeres_ptr (static char *getttyname_name); |
35 | |
36 | static char * |
37 | getttyname (int fd, dev_t mydev, ino_t myino, int save, int *dostat) |
38 | { |
39 | static const char dev[] = "/dev" ; |
40 | static size_t namelen; |
41 | struct stat st; |
42 | DIR *dirstream; |
43 | struct dirent *d; |
44 | |
45 | dirstream = __opendir (name: dev); |
46 | if (dirstream == NULL) |
47 | { |
48 | *dostat = -1; |
49 | return NULL; |
50 | } |
51 | |
52 | while ((d = __readdir (dirp: dirstream)) != NULL) |
53 | if (((ino_t) d->d_fileno == myino || *dostat) |
54 | && strcmp (d->d_name, "stdin" ) |
55 | && strcmp (d->d_name, "stdout" ) |
56 | && strcmp (d->d_name, "stderr" )) |
57 | { |
58 | size_t dlen = _D_ALLOC_NAMLEN (d); |
59 | if (sizeof (dev) + dlen > namelen) |
60 | { |
61 | free (ptr: getttyname_name); |
62 | namelen = 2 * (sizeof (dev) + dlen); /* Big enough. */ |
63 | getttyname_name = malloc (size: namelen); |
64 | if (! getttyname_name) |
65 | { |
66 | *dostat = -1; |
67 | /* Perhaps it helps to free the directory stream buffer. */ |
68 | (void) __closedir (dirp: dirstream); |
69 | return NULL; |
70 | } |
71 | *((char *) __mempcpy (getttyname_name, dev, sizeof (dev) - 1)) |
72 | = '/'; |
73 | } |
74 | (void) __mempcpy (&getttyname_name[sizeof (dev)], d->d_name, dlen); |
75 | if (stat (file: getttyname_name, buf: &st) == 0 |
76 | #ifdef _STATBUF_ST_RDEV |
77 | && S_ISCHR (st.st_mode) && st.st_rdev == mydev |
78 | #else |
79 | && (ino_t) d->d_fileno == myino && st.st_dev == mydev |
80 | #endif |
81 | ) |
82 | { |
83 | (void) __closedir (dirp: dirstream); |
84 | __ttyname = getttyname_name; |
85 | __set_errno (save); |
86 | return getttyname_name; |
87 | } |
88 | } |
89 | |
90 | (void) __closedir (dirp: dirstream); |
91 | __set_errno (save); |
92 | return NULL; |
93 | } |
94 | |
95 | /* Return the pathname of the terminal FD is open on, or NULL on errors. |
96 | The returned storage is good only until the next call to this function. */ |
97 | char * |
98 | ttyname (int fd) |
99 | { |
100 | struct stat st; |
101 | int dostat = 0; |
102 | char *name; |
103 | int save = errno; |
104 | |
105 | if (!__isatty (fd: fd)) |
106 | return NULL; |
107 | |
108 | if (fstat (fd: fd, buf: &st) < 0) |
109 | return NULL; |
110 | |
111 | #ifdef _STATBUF_ST_RDEV |
112 | name = getttyname (fd, mydev: st.st_rdev, myino: st.st_ino, save, dostat: &dostat); |
113 | #else |
114 | name = getttyname (fd, st.st_dev, st.st_ino, save, &dostat); |
115 | #endif |
116 | |
117 | if (!name && dostat != -1) |
118 | { |
119 | dostat = 1; |
120 | #ifdef _STATBUF_ST_RDEV |
121 | name = getttyname (fd, mydev: st.st_rdev, myino: st.st_ino, save, dostat: &dostat); |
122 | #else |
123 | name = getttyname (fd, st.st_dev, st.st_ino, save, &dostat); |
124 | #endif |
125 | } |
126 | |
127 | return name; |
128 | } |
129 | |