lib/libc/gen/ttyname.c

   1 /*
   2  * Copyright (c) 1988, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)ttyname.c        8.2 (Berkeley) 1/27/94
  30  * $FreeBSD: src/lib/libc/gen/ttyname.c,v 1.24 2007/01/09 00:27:55 imp Exp $
  31  */
  32
  33 #include "namespace.h"
  34 #include <sys/types.h>
  35 #include <fcntl.h>
  36 #include <dirent.h>
  37 #include <stdlib.h>
  38 #include <termios.h>
  39 #include <unistd.h>
  40 #include <string.h>
  41 #include <paths.h>
  42 #include <errno.h>
  43 #include <limits.h>
  44 #include <machine/stdint.h>
  45 #include <sys/stat.h>
  46 #include <sys/ioctl.h>
  47 #include "reentrant.h"
  48 #include "un-namespace.h"
  49
  50 #include "libc_private.h"
  51
  52 #define TTYNAME_DEVFS_COMPAT 1
  53
  54 static char ttyname_buf[sizeof(_PATH_DEV) + NAME_MAX];
  55
  56 static once_t           ttyname_init_once = ONCE_INITIALIZER;
  57 static thread_key_t     ttyname_key;
  58 static int              ttyname_keycreated = 0;
  59
  60 int
  61 ttyname_r(int fd, char *buf, size_t len)
  62 {
  63         struct stat     sb;
  64         struct fiodname_args fa;
  65         size_t used;
  66
  67         *buf = '\0';
  68
  69         /* Must be a valid file descriptor */
  70         if (_fstat(fd, &sb))
  71                 return (EBADF);
  72         /* Must be a character device */
  73         if (!S_ISCHR(sb.st_mode))
  74                 return (ENOTTY);
  75         /* Must be a terminal. */
  76         if (!isatty(fd))
  77                 return (ENOTTY);
  78         /* Must have enough room */
  79         if (len <= sizeof(_PATH_DEV))
  80                 return (ERANGE);
  81
  82         strcpy(buf, _PATH_DEV);
  83         used = strlen(buf);
  84         fa.len = len - used;
  85         fa.name = buf + used;
  86         if (_ioctl(fd, FIODNAME, &fa) == -1) {
  87 #ifdef TTYNAME_DEVFS_COMPAT
  88                 /* If compat mode is set, fall back to old method */
  89                 devname_r(sb.st_rdev, S_IFCHR, buf + used, len - used);
  90 #else
  91                 return ERANGE;
  92 #endif
  93         }
  94         return (0);
  95 }
  96
  97 static void
  98 ttyname_keycreate(void)
  99 {
 100         ttyname_keycreated = (thr_keycreate(&ttyname_key, free) == 0);
 101 }
 102
 103 char *
 104 ttyname(int fd)
 105 {
 106         int     error;
 107         char    *buf;
 108
 109         if (thr_main() != 0)
 110                 buf = ttyname_buf;
 111         else {
 112                 if (thr_once(&ttyname_init_once, ttyname_keycreate) != 0 ||
 113                     !ttyname_keycreated)
 114                         return (NULL);
 115                 if ((buf = thr_getspecific(ttyname_key)) == NULL) {
 116                         if ((buf = malloc(sizeof ttyname_buf)) == NULL)
 117                                 return (NULL);
 118                         if (thr_setspecific(ttyname_key, buf) != 0) {
 119                                 free(buf);
 120                                 return (NULL);
 121                         }
 122                 }
 123         }
 124
 125         if (((error = ttyname_r(fd, buf, sizeof ttyname_buf))) != 0) {
 126                 errno = error;
 127                 return (NULL);
 128         }
 129         return (buf);
 130 }