diff options
Diffstat (limited to 'sysdeps/posix/ttyname.c')
-rw-r--r-- | sysdeps/posix/ttyname.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/sysdeps/posix/ttyname.c b/sysdeps/posix/ttyname.c new file mode 100644 index 0000000000..50e3c79341 --- /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; +} |