xref: /titanic_41/usr/src/lib/libc/port/sys/open.c (revision 6d24d8e5e4f6a2d14992d9392981d8a16d695aec)
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 #if defined(_RETAIN_OLD_SYSCALLS)
61 	int fd = syscall(SYS_open, path, oflag, mode);
62 	return (xpg4_fixup(fd));
63 #else
64 	return (__openat(AT_FDCWD, path, oflag, mode));
65 #endif
66 }
67 
68 #if !defined(_LP64)
69 
70 int
71 __openat64(int dfd, const char *path, int oflag, mode_t mode)
72 {
73 	int fd = syscall(SYS_openat64, dfd, path, oflag, mode);
74 	return (xpg4_fixup(fd));
75 }
76 
77 int
78 __open64(const char *path, int oflag, mode_t mode)
79 {
80 #if defined(_RETAIN_OLD_SYSCALLS)
81 	int fd = syscall(SYS_open64, path, oflag, mode);
82 	return (xpg4_fixup(fd));
83 #else
84 	return (__openat64(AT_FDCWD, path, oflag, mode));
85 #endif
86 }
87 
88 #endif	/* !_LP64 */
89 
90 /*
91  * XPG4v2 requires that open of a slave pseudo terminal device
92  * provides the process with an interface that is identical to
93  * the terminal interface. For a more detailed discussion,
94  * see bugid 4025044.
95  */
96 static int
97 xpg4_fixup(int fd)
98 {
99 	if (libc__xpg4 != 0 && fd >= 0 && isptsfd(fd))
100 		push_module(fd);
101 	return (fd);
102 }
103 
104 /*
105  * Check if the file matches an entry in the /dev/pts directory.
106  * Be careful to preserve errno.
107  */
108 static int
109 isptsfd(int fd)
110 {
111 	char buf[TTYNAME_MAX];
112 	char *str1 = buf;
113 	const char *str2 = "/dev/pts/";
114 	struct stat64 fsb, stb;
115 	int oerrno = errno;
116 	int rval = 0;
117 
118 	if (fstat64(fd, &fsb) == 0 && S_ISCHR(fsb.st_mode)) {
119 		/*
120 		 * Do this without strcpy() or strlen(),
121 		 * to avoid invoking the dynamic linker.
122 		 */
123 		while (*str2 != '\0')
124 			*str1++ = *str2++;
125 		/*
126 		 * Inline version of minor(dev), to avoid the dynamic linker.
127 		 */
128 		itoa(fsb.st_rdev & MAXMIN, str1);
129 		if (stat64(buf, &stb) == 0)
130 			rval = (stb.st_rdev == fsb.st_rdev);
131 	}
132 	errno = oerrno;
133 	return (rval);
134 }
135 
136 /*
137  * Converts a number to a string (null terminated).
138  */
139 static void
140 itoa(int i, char *ptr)
141 {
142 	int dig = 0;
143 	int tempi;
144 
145 	tempi = i;
146 	do {
147 		dig++;
148 		tempi /= 10;
149 	} while (tempi);
150 
151 	ptr += dig;
152 	*ptr = '\0';
153 	while (--dig >= 0) {
154 		*(--ptr) = i % 10 + '0';
155 		i /= 10;
156 	}
157 }
158 
159 /*
160  * Push modules to provide tty semantics
161  */
162 static void
163 push_module(int fd)
164 {
165 	struct strioctl istr;
166 	int oerrno = errno;
167 
168 	istr.ic_cmd = PTSSTTY;
169 	istr.ic_len = 0;
170 	istr.ic_timout = 0;
171 	istr.ic_dp = NULL;
172 	if (ioctl(fd, I_STR, &istr) != -1) {
173 		(void) ioctl(fd, __I_PUSH_NOCTTY, "ptem");
174 		(void) ioctl(fd, __I_PUSH_NOCTTY, "ldterm");
175 		(void) ioctl(fd, __I_PUSH_NOCTTY, "ttcompat");
176 		istr.ic_cmd = PTSSTTY;
177 		istr.ic_len = 0;
178 		istr.ic_timout = 0;
179 		istr.ic_dp = NULL;
180 		(void) ioctl(fd, I_STR, &istr);
181 	}
182 	errno = oerrno;
183 }
184