lib/libc/gen/ptsname.c

   1 /*
   2  * Copyright (c) 2009 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Alex Hornung <ahornung@gmail.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34 #include "namespace.h"
  35 #include <sys/types.h>
  36 #include <fcntl.h>
  37 #include <dirent.h>
  38 #include <stdlib.h>
  39 #include <termios.h>
  40 #include <unistd.h>
  41 #include <string.h>
  42 #include <paths.h>
  43 #include <errno.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 ptsname_buf[sizeof(_PATH_DEV) + NAME_MAX];
  55
  56 static once_t           ptsname_init_once = ONCE_INITIALIZER;
  57 static thread_key_t     ptsname_key;
  58 static int              ptsname_keycreated = 0;
  59
  60 static int
  61 __isptmaster(int fd)
  62 {
  63         int error;
  64
  65         error = _ioctl(fd, TIOCISPTMASTER);
  66         if ((error) && (errno != EBADF))
  67                 errno = EINVAL;
  68
  69         return error;
  70 }
  71
  72 static void
  73 ptsname_keycreate(void)
  74 {
  75         ptsname_keycreated = (thr_keycreate(&ptsname_key, free) == 0);
  76 }
  77
  78 char *
  79 ptsname(int fd)
  80 {
  81         int     error;
  82         size_t used;
  83         char    *buf;
  84
  85         error = __isptmaster(fd);
  86         if (error)
  87                 return (error);
  88
  89         if (thr_main() != 0)
  90                 buf = ptsname_buf;
  91         else {
  92                 if (thr_once(&ptsname_init_once, ptsname_keycreate) != 0 ||
  93                     !ptsname_keycreated)
  94                         return (NULL);
  95                 if ((buf = thr_getspecific(ptsname_key)) == NULL) {
  96                         if ((buf = malloc(sizeof ptsname_buf)) == NULL)
  97                                 return (NULL);
  98                         if (thr_setspecific(ptsname_key, buf) != 0) {
  99                                 free(buf);
 100                                 return (NULL);
 101                         }
 102                 }
 103         }
 104
 105         strcpy(buf, "/dev/");
 106         used = strlen(buf);
 107
 108         if (((error = fdevname_r(fd, buf+used, sizeof(ptsname_buf)-used))) != 0) {
 109                 errno = error;
 110                 return (NULL);
 111         }
 112
 113         buf[used+2] = 's';
 114
 115         return (buf);
 116 }
 117
 118 int
 119 posix_openpt(int oflag)
 120 {
 121         return open("/dev/ptmx", oflag);
 122 }
 123
 124 int
 125 unlockpt(int fd)
 126 {
 127         return __isptmaster(fd);
 128 }
 129
 130 int
 131 grantpt(int fd)
 132 {
 133         return __isptmaster(fd);
 134 }