stdlib/grantpt.c

   1 /*
   2  * Copyright (c) 2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include <os/assumes.h>
  25 #include <os/once_private.h>
  26 #include <pthread.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <sys/ioctl.h>
  30 #include <sys/stat.h>
  31 #include <fcntl.h>
  32 #include <errno.h>
  33
  34 /*
  35  * posix_openpt call for cloning pty implementation.
  36  *
  37  * Just open /dev/ptmx
  38  */
  39 int
  40 posix_openpt(int flags)
  41 {
  42         int fd = open("/dev/ptmx", flags);
  43         if (fd >= 0)
  44                 return fd;
  45         return -1;
  46 }
  47
  48 /*
  49  * grantpt call for cloning pty implementation.
  50  *
  51  * Change UID and GID of slave pty associated with master pty whose
  52  * fd is provided, to the real UID and real GID of the calling thread.
  53  */
  54 int
  55 grantpt(int fd)
  56 {
  57         return ioctl(fd, TIOCPTYGRANT);
  58 }
  59
  60 // defined by TIOCPTYGNAME
  61 #define PTSNAME_MAX_SIZE 128
  62
  63 static pthread_key_t ptsname_buffer_specific_key;
  64 static os_once_t ptsname_once;
  65
  66 static void
  67 ptsname_once_init(void *ctx __unused)
  68 {
  69         int ret = pthread_key_create(&ptsname_buffer_specific_key, free);
  70         os_assert_zero(ret);
  71 }
  72
  73 /*
  74  * ptsname call for cloning pty implementation.
  75  *
  76  * NOTE: Returns a pointer to a static buffer, which will be overwritten on
  77  * subsequent calls.
  78  */
  79 char *
  80 ptsname(int fd)
  81 {
  82         os_once(&ptsname_once, NULL, ptsname_once_init);
  83         char *ptsnamebuf = pthread_getspecific(ptsname_buffer_specific_key);
  84
  85         if (ptsnamebuf == NULL) {
  86                 ptsnamebuf = malloc(PTSNAME_MAX_SIZE);
  87                 os_assert(ptsnamebuf);
  88
  89                 int error = pthread_setspecific(ptsname_buffer_specific_key, ptsnamebuf);
  90                 os_assert_zero(error);
  91         }
  92
  93         int error = ptsname_r(fd, ptsnamebuf, PTSNAME_MAX_SIZE);
  94
  95         return error ? NULL : ptsnamebuf;
  96 }
  97
  98 int
  99 ptsname_r(int fd, char *buffer, size_t buflen)
 100 {
 101         int error;
 102         struct stat sbuf;
 103         char ptsnamebuf[PTSNAME_MAX_SIZE];
 104
 105         if (!buffer) {
 106                 errno = EINVAL;
 107                 return -1;
 108         }
 109
 110         error = ioctl(fd, TIOCPTYGNAME, ptsnamebuf);
 111         if (error) {
 112                 return -1;
 113         }
 114
 115         /*
 116          * XXX TSD
 117          *
 118          * POSIX: Handle device rename test case, which is expected
 119          * to fail if the pty has been renamed.
 120          */
 121         error = stat(ptsnamebuf, &sbuf);
 122         if (error) {
 123                 return -1;
 124         }
 125
 126         size_t len = strlen(ptsnamebuf) + 1;
 127         if (buflen < len) {
 128                 errno = ERANGE;
 129                 return -1;
 130         }
 131
 132         memcpy(buffer, ptsnamebuf, len);
 133
 134         return 0;
 135 }
 136
 137 /*
 138  * unlockpt call for cloning pty implementation.
 139  *
 140  * Unlock the slave pty associated with the master to which fd refers.
 141  */
 142 int
 143 unlockpt(int fd)
 144 {
 145         return ioctl(fd, TIOCPTYUNLK);
 146 }