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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /sysdeps/posix/ttyname.c
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initial import
Diffstat (limited to 'sysdeps/posix/ttyname.c')
-rw-r--r--sysdeps/posix/ttyname.c82
1 files changed, 82 insertions, 0 deletions
diff --git a/sysdeps/posix/ttyname.c b/sysdeps/posix/ttyname.c
new file mode 100644
index 0000000..50e3c79
--- /dev/null
+++ b/sysdeps/posix/ttyname.c
@@ -0,0 +1,82 @@
+/* Copyright (C) 1991, 1992, 1993 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., 675 Mass Ave,
+Cambridge, MA 02139, USA. */
+
+#include <ansidecl.h>
+#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>
+
+char *__ttyname = NULL;
+
+/* Return the pathname of the terminal FD is open on, or NULL on errors.
+ The returned storage is good only until the next call to this function. */
+char *
+DEFUN(ttyname, (fd), int fd)
+{
+ static CONST char dev[] = "/dev";
+ static char *name;
+ static size_t namelen = 0;
+ struct stat st;
+ dev_t mydev;
+ ino_t myino;
+ DIR *dirstream;
+ struct dirent *d;
+ int save = errno;
+
+ if (fstat (fd, &st) < 0)
+ return NULL;
+ mydev = st.st_dev;
+ myino = st.st_ino;
+
+ dirstream = opendir (dev);
+ if (dirstream == NULL)
+ return NULL;
+
+ while ((d = readdir (dirstream)) != NULL)
+ if (d->d_fileno == myino)
+ {
+ if (sizeof (dev) + d->d_namlen + 1 > namelen)
+ {
+ free (name);
+ namelen = 2 * (sizeof (dev) + d->d_namlen + 1); /* Big enough. */
+ name = malloc (namelen);
+ if (! name)
+ return NULL;
+ (void) memcpy (name, dev, sizeof (dev) - 1);
+ name[sizeof (dev) - 1] = '/';
+ }
+ (void) memcpy (&name[sizeof (dev)], d->d_name, d->d_namlen + 1);
+ if (stat (name, &st) == 0 && st.st_dev == mydev)
+ {
+ (void) closedir (dirstream);
+ __ttyname = name;
+ errno = save;
+ return name;
+ }
+ }
+
+ (void) closedir (dirstream);
+ errno = save;
+ return NULL;
+}