1 /*
2  * Copyright (c) 2010 Apple Inc. All rights reserved.
3  *
4  * @APPLE_OSREFERENCE_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. The rights granted to you under the License
10  * may not be used to create, or enable the creation or redistribution of,
11  * unlawful or unlicensed copies of an Apple operating system, or to
12  * circumvent, violate, or enable the circumvention or violation of, any
13  * terms of an Apple operating system software license agreement.
14  *
15  * Please obtain a copy of the License at
16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
17  *
18  * The Original Code and all software distributed under the License are
19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23  * Please see the License for the specific language governing rights and
24  * limitations under the License.
25  *
26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27  */
28 
29 #include <TargetConditionals.h>
30 #include <stdbool.h>
31 #include <strings.h>
32 #include <unistd.h>
33 #include "_libkernel_init.h"
34 
35 extern int mach_init(void);
36 
37 #if TARGET_OS_OSX
38 
39 #if !defined(__i386__)
40 
41 #include "system-version-compat-support.h"
42 #include <sys/sysctl.h>
43 
44 extern bool _system_version_compat_check_path_suffix(const char *orig_path);
45 extern int _system_version_compat_open_shim(int opened_fd, int openat_fd, const char *orig_path, int oflag, mode_t mode,
46     int (*close_syscall)(int), int (*open_syscall)(const char *, int, mode_t),
47     int (*openat_syscall)(int, const char *, int, mode_t),
48     int (*fcntl_syscall)(int, int, long));
49 
50 extern bool (*system_version_compat_check_path_suffix)(const char *orig_path);
51 extern int (*system_version_compat_open_shim)(int opened_fd, int openat_fd, const char *orig_path, int oflag, mode_t mode,
52     int (*close_syscall)(int), int (*open_syscall)(const char *, int, mode_t),
53     int (*openat_syscall)(int, const char *, int, mode_t),
54     int (*fcntl_syscall)(int, int, long));
55 
56 extern system_version_compat_mode_t system_version_compat_mode;
57 
58 int  __sysctlbyname(const char *name, size_t namelen, void *oldp, size_t *oldlenp, void *newp, size_t newlen);
59 #endif /* !defined(__i386__) */
60 
61 __attribute__((visibility("default")))
62 extern bool _os_xbs_chrooted;
63 bool _os_xbs_chrooted;
64 #endif /* TARGET_OS_OSX */
65 
66 /* dlsym() funcptr is for legacy support in exc_catcher */
67 void* (*_dlsym)(void*, const char*) __attribute__((visibility("hidden")));
68 
69 __attribute__((visibility("hidden")))
70 _libkernel_functions_t _libkernel_functions;
71 
72 
73 void
74 __libkernel_init(_libkernel_functions_t fns,
75     const char *envp[] __attribute__((unused)),
76     const char *apple[] __attribute__((unused)),
77     const struct ProgramVars *vars __attribute__((unused)))
78 {
79 	_libkernel_functions = fns;
80 	if (fns->dlsym) {
81 		_dlsym = fns->dlsym;
82 	}
83 	mach_init();
84 }
85 
86 void
87 __libkernel_init_late(_libkernel_late_init_config_t config)
88 {
89 	if (config->version >= 1) {
90 #if TARGET_OS_OSX && !defined(__i386__)
91 		if (config->enable_system_version_compat) {
92 			/* enable the version compatibility shim for this process (macOS only) */
93 
94 			/* first hook up the shims we reference from open{at}() */
95 			system_version_compat_check_path_suffix = _system_version_compat_check_path_suffix;
96 			system_version_compat_open_shim = _system_version_compat_open_shim;
97 
98 			system_version_compat_mode = SYSTEM_VERSION_COMPAT_MODE_MACOSX;
99 
100 			/*
101 			 * tell the kernel the shim is enabled for this process so it can shim any
102 			 * necessary sysctls
103 			 */
104 			int enable = 1;
105 			__sysctlbyname("kern.system_version_compat", strlen("kern.system_version_compat"),
106 			    NULL, NULL, &enable, sizeof(enable));
107 		} else if ((config->version >= 2) && config->enable_ios_version_compat) {
108 			/* enable the iOS ProductVersion compatibility shim for this process */
109 
110 			/* first hook up the shims we reference from open{at}() */
111 			system_version_compat_check_path_suffix = _system_version_compat_check_path_suffix;
112 			system_version_compat_open_shim = _system_version_compat_open_shim;
113 
114 			system_version_compat_mode = SYSTEM_VERSION_COMPAT_MODE_IOS;
115 
116 			/*
117 			 * We don't currently shim any sysctls for iOS apps running on macOS so we
118 			 * don't need to inform the kernel that this app has the SystemVersion shim enabled.
119 			 */
120 		}
121 #endif /* TARGET_OS_OSX && !defined(__i386__) */
122 	}
123 }
124