lib/libc/stdlib/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 <limits.h>
  45 #include <machine/stdint.h>
  46 #include <sys/stat.h>
  47 #include <sys/ioctl.h>
  48 #include "reentrant.h"
  49 #include "un-namespace.h"
  50
  51 #include "libc_private.h"
  52
  53 #define TTYNAME_DEVFS_COMPAT 1
  54
  55 static char ptsname_buf[sizeof(_PATH_DEV) + NAME_MAX];
  56
  57 static once_t           ptsname_init_once = ONCE_INITIALIZER;
  58 static thread_key_t     ptsname_key;
  59 static int              ptsname_keycreated = 0;
  60
  61 static int
  62 __isptmaster(int fd)
  63 {
  64         int error;
  65
  66         error = _ioctl(fd, TIOCISPTMASTER);
  67         if ((error) && (errno != EBADF))
  68                 errno = EINVAL;
  69
  70         return error;
  71 }
  72
  73 static void
  74 ptsname_keycreate(void)
  75 {
  76         ptsname_keycreated = (thr_keycreate(&ptsname_key, free) == 0);
  77 }
  78
  79 char *
  80 ptsname(int fd)
  81 {
  82         int     error;
  83         size_t used;
  84         char    *buf;
  85
  86         error = __isptmaster(fd);
  87         if (error)
  88                 return (NULL);
  89
  90         if (thr_main() != 0)
  91                 buf = ptsname_buf;
  92         else {
  93                 if (thr_once(&ptsname_init_once, ptsname_keycreate) != 0 ||
  94                     !ptsname_keycreated)
  95                         return (NULL);
  96                 if ((buf = thr_getspecific(ptsname_key)) == NULL) {
  97                         if ((buf = malloc(sizeof ptsname_buf)) == NULL)
  98                                 return (NULL);
  99                         if (thr_setspecific(ptsname_key, buf) != 0) {
 100                                 free(buf);
 101                                 return (NULL);
 102                         }
 103                 }
 104         }
 105
 106         strcpy(buf, "/dev/");
 107         used = strlen(buf);
 108
 109         if (((error = fdevname_r(fd, buf+used, sizeof(ptsname_buf)-used))) != 0) {
 110                 errno = error;
 111                 return (NULL);
 112         }
 113
 114         buf[used+2] = 's';
 115
 116         return (buf);
 117 }
 118
 119 int
 120 posix_openpt(int oflag)
 121 {
 122         return _open("/dev/ptmx", oflag);
 123 }
 124
 125 int
 126 unlockpt(int fd)
 127 {
 128         return __isptmaster(fd);
 129 }
 130
 131 int
 132 grantpt(int fd)
 133 {
 134         return __isptmaster(fd);
 135 }