1 /*
2 * Copyright (C) 2024 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 #include <android/crash_detail.h>
30
31 #include <async_safe/log.h>
32 #include <bionic/crash_detail_internal.h>
33
34 #include <bits/stdatomic.h>
35 #include <pthread.h>
36 #include <stddef.h>
37 #include <stdint.h>
38 #include <string.h>
39 #include <sys/mman.h>
40 #include <sys/prctl.h>
41
42 #include "private/ScopedPthreadMutexLocker.h"
43 #include "private/bionic_defs.h"
44 #include "private/bionic_globals.h"
45
46 static _Atomic(crash_detail_t*) free_head = nullptr;
47
48 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
android_crash_detail_register(const void * name,size_t name_size,const void * data,size_t data_size)49 crash_detail_t* android_crash_detail_register(const void* name, size_t name_size, const void* data,
50 size_t data_size) {
51 auto populate_crash_detail = [&](crash_detail_t* result) {
52 result->name = reinterpret_cast<const char*>(name);
53 result->name_size = name_size;
54 result->data = reinterpret_cast<const char*>(data);
55 result->data_size = data_size;
56 };
57 // This is a atomic fast-path for RAII use-cases where the app keeps creating and deleting
58 // crash details for short periods of time to capture detailed scopes.
59 if (crash_detail_t* head = atomic_load(&free_head)) {
60 while (head != nullptr && !atomic_compare_exchange_strong(&free_head, &head, head->prev_free)) {
61 // intentionally left blank.
62 }
63 if (head) {
64 head->prev_free = nullptr;
65 populate_crash_detail(head);
66 return head;
67 }
68 }
69 ScopedPthreadMutexLocker locker(&__libc_shared_globals()->crash_detail_page_lock);
70 struct crash_detail_page_t* prev = nullptr;
71 struct crash_detail_page_t* page = __libc_shared_globals()->crash_detail_page;
72 if (page != nullptr && page->used == kNumCrashDetails) {
73 prev = page;
74 page = nullptr;
75 }
76 if (page == nullptr) {
77 size_t size = sizeof(crash_detail_page_t);
78 void* map = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0);
79 if (map == MAP_FAILED) {
80 async_safe_format_log(ANDROID_LOG_ERROR, "libc", "failed to allocate crash_detail_page: %m");
81 return nullptr;
82 }
83 prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, map, size, "crash details");
84 page = reinterpret_cast<struct crash_detail_page_t*>(map);
85 page->prev = prev;
86 __libc_shared_globals()->crash_detail_page = page;
87 }
88 crash_detail_t* result = &page->crash_details[page->used];
89 populate_crash_detail(result);
90 page->used++;
91 return result;
92 }
93
94 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
android_crash_detail_unregister(crash_detail_t * crash_detail)95 void android_crash_detail_unregister(crash_detail_t* crash_detail) {
96 if (crash_detail) {
97 if (crash_detail->prev_free) {
98 // removing already removed would mess up the free-list by creating a circle.
99 return;
100 }
101 crash_detail->data = nullptr;
102 crash_detail->name = nullptr;
103 crash_detail_t* prev = atomic_load(&free_head);
104 do {
105 crash_detail->prev_free = prev;
106 } while (!atomic_compare_exchange_strong(&free_head, &prev, crash_detail));
107 }
108 }
109
110 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
android_crash_detail_replace_data(crash_detail_t * crash_detail,const void * data,size_t data_size)111 void android_crash_detail_replace_data(crash_detail_t* crash_detail, const void* data,
112 size_t data_size) {
113 crash_detail->data = reinterpret_cast<const char*>(data);
114 crash_detail->data_size = data_size;
115 }
116
117 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
android_crash_detail_replace_name(crash_detail_t * crash_detail,const void * name,size_t name_size)118 void android_crash_detail_replace_name(crash_detail_t* crash_detail, const void* name,
119 size_t name_size) {
120 crash_detail->name = reinterpret_cast<const char*>(name);
121 crash_detail->name_size = name_size;
122 }
123