1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *  * Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  *  * Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in
12  *    the documentation and/or other materials provided with the
13  *    distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #ifndef _PRIVATE_BIONIC_GLOBALS_H
30 #define _PRIVATE_BIONIC_GLOBALS_H
31 
32 #include <stdatomic.h>
33 #include <sys/cdefs.h>
34 #include <link.h>
35 #include <pthread.h>
36 
37 #include "private/bionic_allocator.h"
38 #include "private/bionic_elf_tls.h"
39 #include "private/bionic_fdsan.h"
40 #include "private/bionic_malloc_dispatch.h"
41 #include "private/bionic_vdso.h"
42 #include "private/WriteProtected.h"
43 
44 #include <platform/bionic/malloc.h>
45 
46 struct libc_globals {
47   vdso_entry vdso[VDSO_END];
48   long setjmp_cookie;
49   uintptr_t heap_pointer_tag;
50 
51   // In order to allow a complete switch between dispatch tables without
52   // the need for copying each function by function in the structure,
53   // use a single atomic pointer to switch.
54   // The current_dispatch_table pointer can only ever be set to a complete
55   // table. Any dispatch table that is pointed to by current_dispatch_table
56   // cannot be modified after that. If the pointer changes in the future,
57   // the old pointer must always stay valid.
58   // The malloc_dispatch_table is modified by malloc debug, malloc hooks,
59   // and heaprofd. Only one of these modes can be active at any given time.
60   _Atomic(const MallocDispatch*) current_dispatch_table;
61   // This pointer is only used by the allocation limit code when both a
62   // limit is enabled and some other hook is enabled at the same time.
63   _Atomic(const MallocDispatch*) default_dispatch_table;
64   MallocDispatch malloc_dispatch_table;
65 };
66 
67 __LIBC_HIDDEN__ extern WriteProtected<libc_globals> __libc_globals;
68 
69 struct abort_msg_t;
70 namespace gwp_asan {
71 struct AllocatorState;
72 struct AllocationMetadata;
73 };  // namespace gwp_asan
74 
75 // Globals shared between the dynamic linker and libc.so.
76 struct libc_shared_globals {
77   // Construct the shared globals using a constexpr constructor to ensure that
78   // the object doesn't need dynamic initialization. The object is accessed
79   // before the dynamic linker has relocated itself.
libc_shared_globalslibc_shared_globals80   constexpr libc_shared_globals() {}
81 
82   FdTable fd_table;
83 
84   // When the linker is invoked on a binary (e.g. `linker64 /system/bin/date`),
85   // record the number of arguments passed to the linker itself rather than to
86   // the program it's loading. Typically 0, sometimes 1.
87   int initial_linker_arg_count = 0;
88 
89   ElfW(auxv_t)* auxv = nullptr;
90 
91   pthread_mutex_t abort_msg_lock = PTHREAD_MUTEX_INITIALIZER;
92   abort_msg_t* abort_msg = nullptr;
93 
94   StaticTlsLayout static_tls_layout;
95   TlsModules tls_modules;
96   BionicAllocator tls_allocator;
97 
98   // Values passed from libc.so to the loader.
99   void (*load_hook)(ElfW(Addr) base, const ElfW(Phdr)* phdr, ElfW(Half) phnum) = nullptr;
100   void (*unload_hook)(ElfW(Addr) base, const ElfW(Phdr)* phdr, ElfW(Half) phnum) = nullptr;
101   void (*set_target_sdk_version_hook)(int target) = nullptr;
102 
103   // Values passed from the linker to libc.so.
104   const char* init_progname = nullptr;
105   char** init_environ = nullptr;
106 
107   const gwp_asan::AllocatorState* gwp_asan_state = nullptr;
108   const gwp_asan::AllocationMetadata* gwp_asan_metadata = nullptr;
109 
110   const char* scudo_stack_depot = nullptr;
111   const char* scudo_region_info = nullptr;
112   const char* scudo_ring_buffer = nullptr;
113 
114   HeapTaggingLevel initial_heap_tagging_level = M_HEAP_TAGGING_LEVEL_NONE;
115 };
116 
117 __LIBC_HIDDEN__ libc_shared_globals* __libc_shared_globals();
118 __LIBC_HIDDEN__ void __libc_init_fdsan();
119 __LIBC_HIDDEN__ void __libc_init_fdtrack();
120 __LIBC_HIDDEN__ void __libc_init_profiling_handlers();
121 
122 __LIBC_HIDDEN__ void __libc_init_malloc(libc_globals* globals);
123 __LIBC_HIDDEN__ void __libc_init_setjmp_cookie(libc_globals* globals);
124 __LIBC_HIDDEN__ void __libc_init_vdso(libc_globals* globals);
125 
126 #if defined(__i386__)
127 __LIBC_HIDDEN__ extern void* __libc_sysinfo;
128 extern "C" __LIBC_HIDDEN__ void __libc_int0x80();
129 __LIBC_HIDDEN__ void __libc_init_sysinfo();
130 #endif
131 
132 #endif
133