1 | /* Copyright (C) 1991-2017 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 | <http://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 <termios.h> |
25 | #include <unistd.h> |
26 | #include <string.h> |
27 | #include <stdlib.h> |
28 | |
29 | #include <_itoa.h> |
30 | |
31 | #if 0 |
32 | /* Is this used anywhere? It is not exported. */ |
33 | char *__ttyname; |
34 | #endif |
35 | |
36 | static char *getttyname (const char *dev, dev_t mydev, |
37 | ino64_t myino, int save, int *dostat) |
38 | internal_function; |
39 | |
40 | |
41 | libc_freeres_ptr (static char *getttyname_name); |
42 | |
43 | static char * |
44 | internal_function attribute_compat_text_section |
45 | getttyname (const char *dev, dev_t mydev, ino64_t myino, int save, int *dostat) |
46 | { |
47 | static size_t namelen; |
48 | struct stat64 st; |
49 | DIR *dirstream; |
50 | struct dirent64 *d; |
51 | size_t devlen = strlen (dev) + 1; |
52 | |
53 | dirstream = __opendir (dev); |
54 | if (dirstream == NULL) |
55 | { |
56 | *dostat = -1; |
57 | return NULL; |
58 | } |
59 | |
60 | /* Prepare for the loop. If we already have a buffer copy the directory |
61 | name we look at into it. */ |
62 | if (devlen < namelen) |
63 | *((char *) __mempcpy (getttyname_name, dev, devlen - 1)) = '/'; |
64 | |
65 | while ((d = __readdir64 (dirstream)) != NULL) |
66 | if ((d->d_fileno == myino || *dostat) |
67 | && strcmp (d->d_name, "stdin" ) |
68 | && strcmp (d->d_name, "stdout" ) |
69 | && strcmp (d->d_name, "stderr" )) |
70 | { |
71 | size_t dlen = _D_ALLOC_NAMLEN (d); |
72 | if (devlen + dlen > namelen) |
73 | { |
74 | free (getttyname_name); |
75 | namelen = 2 * (devlen + dlen); /* Big enough. */ |
76 | getttyname_name = malloc (namelen); |
77 | if (! getttyname_name) |
78 | { |
79 | *dostat = -1; |
80 | /* Perhaps it helps to free the directory stream buffer. */ |
81 | (void) __closedir (dirstream); |
82 | return NULL; |
83 | } |
84 | *((char *) __mempcpy (getttyname_name, dev, devlen - 1)) = '/'; |
85 | } |
86 | memcpy (&getttyname_name[devlen], d->d_name, dlen); |
87 | if (__xstat64 (_STAT_VER, getttyname_name, &st) == 0 |
88 | #ifdef _STATBUF_ST_RDEV |
89 | && S_ISCHR (st.st_mode) && st.st_rdev == mydev |
90 | #else |
91 | && d->d_fileno == myino && st.st_dev == mydev |
92 | #endif |
93 | ) |
94 | { |
95 | (void) __closedir (dirstream); |
96 | #if 0 |
97 | __ttyname = getttyname_name; |
98 | #endif |
99 | __set_errno (save); |
100 | return getttyname_name; |
101 | } |
102 | } |
103 | |
104 | (void) __closedir (dirstream); |
105 | __set_errno (save); |
106 | return NULL; |
107 | } |
108 | |
109 | |
110 | /* Static buffer in `ttyname'. */ |
111 | libc_freeres_ptr (static char *ttyname_buf); |
112 | |
113 | |
114 | /* Return the pathname of the terminal FD is open on, or NULL on errors. |
115 | The returned storage is good only until the next call to this function. */ |
116 | char * |
117 | ttyname (int fd) |
118 | { |
119 | static size_t buflen; |
120 | char procname[30]; |
121 | struct stat64 st, st1; |
122 | int dostat = 0; |
123 | char *name; |
124 | int save = errno; |
125 | struct termios term; |
126 | |
127 | /* isatty check, tcgetattr is used because it sets the correct |
128 | errno (EBADF resp. ENOTTY) on error. */ |
129 | if (__glibc_unlikely (__tcgetattr (fd, &term) < 0)) |
130 | return NULL; |
131 | |
132 | if (__fxstat64 (_STAT_VER, fd, &st) < 0) |
133 | return NULL; |
134 | |
135 | /* We try using the /proc filesystem. */ |
136 | *_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/" ), 10, 0) = '\0'; |
137 | |
138 | if (buflen == 0) |
139 | { |
140 | buflen = 4095; |
141 | ttyname_buf = (char *) malloc (buflen + 1); |
142 | if (ttyname_buf == NULL) |
143 | { |
144 | buflen = 0; |
145 | return NULL; |
146 | } |
147 | } |
148 | |
149 | ssize_t len = __readlink (procname, ttyname_buf, buflen); |
150 | if (__glibc_likely (len != -1)) |
151 | { |
152 | if ((size_t) len >= buflen) |
153 | return NULL; |
154 | |
155 | #define UNREACHABLE_LEN strlen ("(unreachable)") |
156 | if (len > UNREACHABLE_LEN |
157 | && memcmp (ttyname_buf, "(unreachable)" , UNREACHABLE_LEN) == 0) |
158 | { |
159 | memmove (ttyname_buf, ttyname_buf + UNREACHABLE_LEN, |
160 | len - UNREACHABLE_LEN); |
161 | len -= UNREACHABLE_LEN; |
162 | } |
163 | |
164 | /* readlink need not terminate the string. */ |
165 | ttyname_buf[len] = '\0'; |
166 | |
167 | /* Verify readlink result, fall back on iterating through devices. */ |
168 | if (ttyname_buf[0] == '/' |
169 | && __xstat64 (_STAT_VER, ttyname_buf, &st1) == 0 |
170 | #ifdef _STATBUF_ST_RDEV |
171 | && S_ISCHR (st1.st_mode) |
172 | && st1.st_rdev == st.st_rdev |
173 | #else |
174 | && st1.st_ino == st.st_ino |
175 | && st1.st_dev == st.st_dev |
176 | #endif |
177 | ) |
178 | return ttyname_buf; |
179 | } |
180 | |
181 | if (__xstat64 (_STAT_VER, "/dev/pts" , &st1) == 0 && S_ISDIR (st1.st_mode)) |
182 | { |
183 | #ifdef _STATBUF_ST_RDEV |
184 | name = getttyname ("/dev/pts" , st.st_rdev, st.st_ino, save, &dostat); |
185 | #else |
186 | name = getttyname ("/dev/pts" , st.st_dev, st.st_ino, save, &dostat); |
187 | #endif |
188 | } |
189 | else |
190 | { |
191 | __set_errno (save); |
192 | name = NULL; |
193 | } |
194 | |
195 | if (!name && dostat != -1) |
196 | { |
197 | #ifdef _STATBUF_ST_RDEV |
198 | name = getttyname ("/dev" , st.st_rdev, st.st_ino, save, &dostat); |
199 | #else |
200 | name = getttyname ("/dev" , st.st_dev, st.st_ino, save, &dostat); |
201 | #endif |
202 | } |
203 | |
204 | if (!name && dostat != -1) |
205 | { |
206 | dostat = 1; |
207 | #ifdef _STATBUF_ST_RDEV |
208 | name = getttyname ("/dev" , st.st_rdev, st.st_ino, save, &dostat); |
209 | #else |
210 | name = getttyname ("/dev" , st.st_dev, st.st_ino, save, &dostat); |
211 | #endif |
212 | } |
213 | |
214 | return name; |
215 | } |
216 | |