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[glibc.git] / sysdeps / posix / ttyname_r.c
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1 /* Copyright (C) 1991, 92, 93, 95, 96, 97, 98 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
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.
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.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17 02111-1307 USA. */
19 #include <errno.h>
20 #include <limits.h>
21 #include <stddef.h>
22 #include <dirent.h>
23 #include <sys/types.h>
24 #include <sys/stat.h>
25 #include <unistd.h>
26 #include <string.h>
27 #include <stdlib.h>
29 #ifndef MIN
30 # define MIN(a, b) ((a) < (b) ? (a) : (b))
31 #endif
33 static const char dev[] = "/dev";
35 static int getttyname_r __P ((int fd, char *buf, size_t buflen,
36 dev_t mydev, ino_t myino, int save,
37 int *dostat)) internal_function;
39 static int
40 internal_function
41 getttyname_r (fd, buf, buflen, mydev, myino, save, dostat)
42 int fd;
43 char *buf;
44 size_t buflen;
45 dev_t mydev;
46 ino_t myino;
47 int save;
48 int *dostat;
50 struct stat st;
51 DIR *dirstream;
52 struct dirent *d;
54 dirstream = __opendir (dev);
55 if (dirstream == NULL)
57 *dostat = -1;
58 return errno;
61 while ((d = __readdir (dirstream)) != NULL)
62 if (((ino_t) d->d_fileno == myino || *dostat)
63 && strcmp (d->d_name, "stdin")
64 && strcmp (d->d_name, "stdout")
65 && strcmp (d->d_name, "stderr"))
67 char *cp;
68 size_t needed = _D_EXACT_NAMLEN (d) + 1;
70 if (needed > buflen)
72 *dostat = -1;
73 (void) __closedir (dirstream);
74 __set_errno (ERANGE);
75 return ERANGE;
78 cp = __stpncpy (&buf[sizeof (dev)], d->d_name, needed);
79 cp[0] = '\0';
81 if (stat (buf, &st) == 0
82 #ifdef _STATBUF_ST_RDEV
83 && S_ISCHR (st.st_mode) && st.st_rdev == mydev
84 #else
85 && (ino_t) d->d_fileno == myino && st.st_dev == mydev
86 #endif
89 (void) __closedir (dirstream);
90 __set_errno (save);
91 return 0;
95 (void) __closedir (dirstream);
96 __set_errno (save);
97 /* It is not clear what to return in this case. `isatty' says FD
98 refers to a TTY but no entry in /dev has this inode. */
99 return ENOTTY;
102 /* Store at most BUFLEN character of the pathname of the terminal FD is
103 open on in BUF. Return 0 on success, otherwise an error number. */
105 __ttyname_r (fd, buf, buflen)
106 int fd;
107 char *buf;
108 size_t buflen;
110 struct stat st;
111 int dostat = 0;
112 int save = errno;
113 int ret;
115 /* Test for the absolute minimal size. This makes life easier inside
116 the loop. */
117 if (!buf)
119 __set_errno (EINVAL);
120 return EINVAL;
123 if (buflen < (int) (sizeof (dev) + 1))
125 __set_errno (ERANGE);
126 return ERANGE;
129 if (!__isatty (fd))
131 __set_errno (ENOTTY);
132 return ENOTTY;
135 if (fstat (fd, &st) < 0)
136 return errno;
138 /* Prepare the result buffer. */
139 memcpy (buf, dev, sizeof (dev) - 1);
140 buf[sizeof (dev) - 1] = '/';
141 buflen -= sizeof (dev);
143 #ifdef _STATBUF_ST_RDEV
144 ret = getttyname_r (fd, buf, buflen, st.st_rdev, st.st_ino, save,
145 &dostat);
146 #else
147 ret = getttyname_r (fd, buf, buflen, st.st_dev, st.st_ino, save,
148 &dostat);
149 #endif
151 if (ret && dostat != -1)
153 dostat = 1;
154 #ifdef _STATBUF_ST_RDEV
155 ret = getttyname_r (fd, buf, buflen, st.st_rdev, st.st_ino,
156 save, &dostat);
157 #else
158 ret = getttyname_r (fd, buf, buflen, st.st_dev, st.st_ino,
159 save, &dostat);
160 #endif
163 return ret;
166 weak_alias (__ttyname_r, ttyname_r)