libsyscall/wrappers/_libkernel_init.c

   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 <mach/vm_page_size.h>
  34 #include "_libkernel_init.h"
  35
  36 extern int mach_init(void);
  37
  38 #if TARGET_OS_OSX
  39
  40 #if !defined(__i386__)
  41
  42 #include "system-version-compat-support.h"
  43 #include <sys/sysctl.h>
  44
  45 extern bool _system_version_compat_check_path_suffix(const char *orig_path);
  46 extern int _system_version_compat_open_shim(int opened_fd, int openat_fd, const char *orig_path, int oflag, mode_t mode,
  47     int (*close_syscall)(int), int (*open_syscall)(const char *, int, mode_t),
  48     int (*openat_syscall)(int, const char *, int, mode_t),
  49     int (*fcntl_syscall)(int, int, long));
  50
  51 extern bool (*system_version_compat_check_path_suffix)(const char *orig_path);
  52 extern int (*system_version_compat_open_shim)(int opened_fd, int openat_fd, const char *orig_path, int oflag, mode_t mode,
  53     int (*close_syscall)(int), int (*open_syscall)(const char *, int, mode_t),
  54     int (*openat_syscall)(int, const char *, int, mode_t),
  55     int (*fcntl_syscall)(int, int, long));
  56
  57 extern system_version_compat_mode_t system_version_compat_mode;
  58
  59 int  __sysctlbyname(const char *name, size_t namelen, void *oldp, size_t *oldlenp, void *newp, size_t newlen);
  60 #endif /* !defined(__i386__) */
  61
  62 __attribute__((visibility("default")))
  63 extern bool _os_xbs_chrooted;
  64 bool _os_xbs_chrooted;
  65 #endif /* TARGET_OS_OSX */
  66
  67 /* dlsym() funcptr is for legacy support in exc_catcher */
  68 void* (*_dlsym)(void*, const char*) __attribute__((visibility("hidden")));
  69
  70 __attribute__((visibility("hidden")))
  71 _libkernel_functions_t _libkernel_functions;
  72
  73
  74 void
  75 __libkernel_init(_libkernel_functions_t fns,
  76     const char *envp[] __attribute__((unused)),
  77     const char *apple[] __attribute__((unused)),
  78     const struct ProgramVars *vars __attribute__((unused)))
  79 {
  80         _libkernel_functions = fns;
  81         if (fns->dlsym) {
  82                 _dlsym = fns->dlsym;
  83         }
  84         mach_init();
  85 #if TARGET_OS_OSX
  86         for (size_t i = 0; envp[i]; i++) {
  87
  88 #if defined(__i386__) || defined(__x86_64__)
  89                 const char *VM_KERNEL_PAGE_SHIFT_ENV = "VM_KERNEL_PAGE_SIZE_4K=1";
  90                 if (vm_kernel_page_shift != 12 && strcmp(VM_KERNEL_PAGE_SHIFT_ENV, envp[i]) == 0) {
  91                         vm_kernel_page_shift = 12;
  92                         vm_kernel_page_size = 1 << vm_kernel_page_shift;
  93                         vm_kernel_page_mask = vm_kernel_page_size - 1;
  94                 }
  95 #endif /* defined(__i386__) || defined(__x86_64__) */
  96         }
  97 #endif /* TARGET_OS_OSX */
  98 }
  99
 100 void
 101 __libkernel_init_late(_libkernel_late_init_config_t config)
 102 {
 103         if (config->version >= 1) {
 104 #if TARGET_OS_OSX && !defined(__i386__)
 105                 if (config->enable_system_version_compat) {
 106                         /* enable the version compatibility shim for this process (macOS only) */
 107
 108                         /* first hook up the shims we reference from open{at}() */
 109                         system_version_compat_check_path_suffix = _system_version_compat_check_path_suffix;
 110                         system_version_compat_open_shim = _system_version_compat_open_shim;
 111
 112                         system_version_compat_mode = SYSTEM_VERSION_COMPAT_MODE_MACOSX;
 113
 114                         /*
 115                          * tell the kernel the shim is enabled for this process so it can shim any
 116                          * necessary sysctls
 117                          */
 118                         int enable = 1;
 119                         __sysctlbyname("kern.system_version_compat", strlen("kern.system_version_compat"),
 120                             NULL, NULL, &enable, sizeof(enable));
 121                 } else if ((config->version >= 2) && config->enable_ios_version_compat) {
 122                         /* enable the iOS ProductVersion compatibility shim for this process */
 123
 124                         /* first hook up the shims we reference from open{at}() */
 125                         system_version_compat_check_path_suffix = _system_version_compat_check_path_suffix;
 126                         system_version_compat_open_shim = _system_version_compat_open_shim;
 127
 128                         system_version_compat_mode = SYSTEM_VERSION_COMPAT_MODE_IOS;
 129
 130                         /*
 131                          * We don't currently shim any sysctls for iOS apps running on macOS so we
 132                          * don't need to inform the kernel that this app has the SystemVersion shim enabled.
 133                          */
 134                 }
 135 #endif /* TARGET_OS_OSX && !defined(__i386__) */
 136         }
 137 }