about summary refs log tree commit diff
path: root/sysdeps/unix/sysv/linux/ttyname_r.c
blob: ae5a029e658a2374646f21a6dc68d3b98be7f101 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
/* Copyright (C) 1991,92,93,95,96,97,98,99 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 Library General Public License as
   published by the Free Software Foundation; either version 2 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>

#include <stdio-common/_itoa.h>

static int getttyname_r __P ((char *buf, size_t buflen,
			      dev_t mydev, ino_t myino, int save,
			      int *dostat)) internal_function;

static int
internal_function
getttyname_r (buf, buflen, mydev, myino, save, dostat)
     char *buf;
     size_t buflen;
     dev_t mydev;
     ino_t myino;
     int save;
     int *dostat;
{
  struct stat st;
  DIR *dirstream;
  struct dirent *d;
  size_t devlen = strlen (buf);

  dirstream = __opendir (buf);
  if (dirstream == NULL)
    {
      *dostat = -1;
      return errno;
    }

  while ((d = __readdir (dirstream)) != NULL)
    if (((ino_t) d->d_fileno == myino || *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 (__xstat (_STAT_VER, buf, &st) == 0
#ifdef _STATBUF_ST_RDEV
	    && S_ISCHR (st.st_mode) && st.st_rdev == mydev
#else
	    && (ino_t) d->d_fileno == myino && st.st_dev == mydev
#endif
	   )
	  {
	    (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 (fd, buf, buflen)
     int fd;
     char *buf;
     size_t buflen;
{
  static int dev_pts_available = 1;
  char procname[30];
  struct stat st, st1;
  int dostat = 0;
  int save = errno;
  int ret;

  /* 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;
    }

  if (!__isatty (fd))
    {
      __set_errno (ENOTTY);
      return ENOTTY;
    }

  /* We try using the /proc filesystem.  */
  *_fitoa_word (fd, __stpcpy (procname, "/proc/self/fd/"), 10, 0) = '\0';

  ret = __readlink (procname, buf, buflen - 1);
  if (ret != -1 && buf[0] != '[')
    return 0;
  if (ret == -1 && errno == ENAMETOOLONG)
    {
      __set_errno (ERANGE);
      return ERANGE;
    }

  if (__fxstat (_STAT_VER, fd, &st) < 0)
    return errno;

  /* Prepare the result buffer.  */
  memcpy (buf, "/dev/pts/", sizeof ("/dev/pts/"));
  buflen -= sizeof ("/dev/pts/") - 1;

  if (dev_pts_available)
    {
      if (__xstat (_STAT_VER, buf, &st1) == 0 && S_ISDIR (st1.st_mode))
	{
#ifdef _STATBUF_ST_RDEV
	  ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino, save,
			      &dostat);
#else
	  ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino, save,
			      &dostat);
#endif
	}
      else
	{
	  __set_errno (save);
	  ret = ENOENT;
	}
      else
	{
	  __set_errno (save);
	  dev_pts_available = 0;
	}
    }

  if (ret && dostat != -1)
    {
      buf[sizeof ("/dev/") - 1] = '\0';
      buflen += sizeof ("pts/") - 1;
#ifdef _STATBUF_ST_RDEV
      ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino, save,
			  &dostat);
#else
      ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino, save,
			  &dostat);
#endif
    }

  if (ret && dostat != -1)
    {
      buf[sizeof ("/dev/") - 1] = '\0';
      dostat = 1;
#ifdef _STATBUF_ST_RDEV
      ret = getttyname_r (buf, buflen, st.st_rdev, st.st_ino,
			  save, &dostat);
#else
      ret = getttyname_r (buf, buflen, st.st_dev, st.st_ino,
			  save, &dostat);
#endif
    }

  return ret;
}

weak_alias (__ttyname_r, ttyname_r)