usr/src/lib/libc/port/sys/open.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #include "lint.h"
  31 #include <sys/mkdev.h>
  32 #include <limits.h>
  33 #include <stdarg.h>
  34 #include <unistd.h>
  35 #include <strings.h>
  36 #include <errno.h>
  37 #include <sys/stat.h>
  38 #include <sys/fcntl.h>
  39 #include <sys/stropts.h>
  40 #include <sys/stream.h>
  41 #include <sys/ptms.h>
  42 #include <sys/syscall.h>
  43 #include "libc.h"
  44
  45 static int xpg4_fixup(int fd);
  46 static void push_module(int fd);
  47 static int isptsfd(int fd);
  48 static void itoa(int i, char *ptr);
  49
  50 int
  51 __openat(int dfd, const char *path, int oflag, mode_t mode)
  52 {
  53         int fd = syscall(SYS_openat, dfd, path, oflag, mode);
  54         return (xpg4_fixup(fd));
  55 }
  56
  57 int
  58 __open(const char *path, int oflag, mode_t mode)
  59 {
  60         return (__openat(AT_FDCWD, path, oflag, mode));
  61 }
  62
  63 #if !defined(_LP64)
  64
  65 int
  66 __openat64(int dfd, const char *path, int oflag, mode_t mode)
  67 {
  68         int fd = syscall(SYS_openat64, dfd, path, oflag, mode);
  69         return (xpg4_fixup(fd));
  70 }
  71
  72 int
  73 __open64(const char *path, int oflag, mode_t mode)
  74 {
  75         return (__openat64(AT_FDCWD, path, oflag, mode));
  76 }
  77
  78 #endif  /* !_LP64 */
  79
  80 /*
  81  * XPG4v2 requires that open of a slave pseudo terminal device
  82  * provides the process with an interface that is identical to
  83  * the terminal interface. For a more detailed discussion,
  84  * see bugid 4025044.
  85  */
  86 static int
  87 xpg4_fixup(int fd)
  88 {
  89         if (libc__xpg4 != 0 && fd >= 0 && isptsfd(fd))
  90                 push_module(fd);
  91         return (fd);
  92 }
  93
  94 /*
  95  * Check if the file matches an entry in the /dev/pts directory.
  96  * Be careful to preserve errno.
  97  */
  98 static int
  99 isptsfd(int fd)
 100 {
 101         char buf[TTYNAME_MAX];
 102         char *str1 = buf;
 103         const char *str2 = "/dev/pts/";
 104         struct stat64 fsb, stb;
 105         int oerrno = errno;
 106         int rval = 0;
 107
 108         if (fstat64(fd, &fsb) == 0 && S_ISCHR(fsb.st_mode)) {
 109                 /*
 110                  * Do this without strcpy() or strlen(),
 111                  * to avoid invoking the dynamic linker.
 112                  */
 113                 while (*str2 != '\0')
 114                         *str1++ = *str2++;
 115                 /*
 116                  * Inline version of minor(dev), to avoid the dynamic linker.
 117                  */
 118                 itoa(fsb.st_rdev & MAXMIN, str1);
 119                 if (stat64(buf, &stb) == 0)
 120                         rval = (stb.st_rdev == fsb.st_rdev);
 121         }
 122         errno = oerrno;
 123         return (rval);
 124 }
 125
 126 /*
 127  * Converts a number to a string (null terminated).
 128  */
 129 static void
 130 itoa(int i, char *ptr)
 131 {
 132         int dig = 0;
 133         int tempi;
 134
 135         tempi = i;
 136         do {
 137                 dig++;
 138                 tempi /= 10;
 139         } while (tempi);
 140
 141         ptr += dig;
 142         *ptr = '\0';
 143         while (--dig >= 0) {
 144                 *(--ptr) = i % 10 + '0';
 145                 i /= 10;
 146         }
 147 }
 148
 149 /*
 150  * Push modules to provide tty semantics
 151  */
 152 static void
 153 push_module(int fd)
 154 {
 155         struct strioctl istr;
 156         int oerrno = errno;
 157
 158         istr.ic_cmd = PTSSTTY;
 159         istr.ic_len = 0;
 160         istr.ic_timout = 0;
 161         istr.ic_dp = NULL;
 162         if (ioctl(fd, I_STR, &istr) != -1) {
 163                 (void) ioctl(fd, __I_PUSH_NOCTTY, "ptem");
 164                 (void) ioctl(fd, __I_PUSH_NOCTTY, "ldterm");
 165                 (void) ioctl(fd, __I_PUSH_NOCTTY, "ttcompat");
 166                 istr.ic_cmd = PTSSTTY;
 167                 istr.ic_len = 0;
 168                 istr.ic_timout = 0;
 169                 istr.ic_dp = NULL;
 170                 (void) ioctl(fd, I_STR, &istr);
 171         }
 172         errno = oerrno;
 173 }