1//===-- guarded_pool_allocator_posix.cpp ------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "gwp_asan/common.h"
10#include "gwp_asan/guarded_pool_allocator.h"
11#include "gwp_asan/platform_specific/guarded_pool_allocator_tls.h"
12#include "gwp_asan/utilities.h"
13
14#include <assert.h>
15#include <pthread.h>
16#include <stdint.h>
17#include <stdlib.h>
18#include <sys/mman.h>
19#include <time.h>
20#include <unistd.h>
21
22#ifdef ANDROID
23#include <sys/prctl.h>
24#define PR_SET_VMA 0x53564d41
25#define PR_SET_VMA_ANON_NAME 0
26#endif // ANDROID
27
28namespace {
29void MaybeSetMappingName(void *Mapping, size_t Size, const char *Name) {
30#ifdef ANDROID
31 prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, Mapping, Size, Name);
32#endif // ANDROID
33 // Anonymous mapping names are only supported on Android.
34 return;
35}
36} // anonymous namespace
37
38namespace gwp_asan {
39
40void GuardedPoolAllocator::initPRNG() {
41 getThreadLocals()->RandomState =
42 static_cast<uint32_t>(time(timer: nullptr) + getThreadID());
43}
44
45void *GuardedPoolAllocator::map(size_t Size, const char *Name) const {
46 assert((Size % State.PageSize) == 0);
47 void *Ptr = mmap(addr: nullptr, len: Size, PROT_READ | PROT_WRITE,
48 MAP_ANONYMOUS | MAP_PRIVATE, fd: -1, offset: 0);
49 Check(Condition: Ptr != MAP_FAILED, Message: "Failed to map guarded pool allocator memory");
50 MaybeSetMappingName(Mapping: Ptr, Size, Name);
51 return Ptr;
52}
53
54void GuardedPoolAllocator::unmap(void *Ptr, size_t Size) const {
55 assert((reinterpret_cast<uintptr_t>(Ptr) % State.PageSize) == 0);
56 assert((Size % State.PageSize) == 0);
57 Check(Condition: munmap(addr: Ptr, len: Size) == 0,
58 Message: "Failed to unmap guarded pool allocator memory.");
59}
60
61void *GuardedPoolAllocator::reserveGuardedPool(size_t Size) {
62 assert((Size % State.PageSize) == 0);
63 void *Ptr =
64 mmap(addr: nullptr, len: Size, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, fd: -1, offset: 0);
65 Check(Condition: Ptr != MAP_FAILED, Message: "Failed to reserve guarded pool allocator memory");
66 MaybeSetMappingName(Mapping: Ptr, Size, Name: kGwpAsanGuardPageName);
67 return Ptr;
68}
69
70void GuardedPoolAllocator::unreserveGuardedPool() {
71 unmap(Ptr: reinterpret_cast<void *>(State.GuardedPagePool),
72 Size: State.GuardedPagePoolEnd - State.GuardedPagePool);
73}
74
75void GuardedPoolAllocator::allocateInGuardedPool(void *Ptr, size_t Size) const {
76 assert((reinterpret_cast<uintptr_t>(Ptr) % State.PageSize) == 0);
77 assert((Size % State.PageSize) == 0);
78 Check(Condition: mprotect(addr: Ptr, len: Size, PROT_READ | PROT_WRITE) == 0,
79 Message: "Failed to allocate in guarded pool allocator memory");
80 MaybeSetMappingName(Mapping: Ptr, Size, Name: kGwpAsanAliveSlotName);
81}
82
83void GuardedPoolAllocator::deallocateInGuardedPool(void *Ptr,
84 size_t Size) const {
85 assert((reinterpret_cast<uintptr_t>(Ptr) % State.PageSize) == 0);
86 assert((Size % State.PageSize) == 0);
87 // mmap() a PROT_NONE page over the address to release it to the system, if
88 // we used mprotect() here the system would count pages in the quarantine
89 // against the RSS.
90 Check(Condition: mmap(addr: Ptr, len: Size, PROT_NONE, MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE, fd: -1,
91 offset: 0) != MAP_FAILED,
92 Message: "Failed to deallocate in guarded pool allocator memory");
93 MaybeSetMappingName(Mapping: Ptr, Size, Name: kGwpAsanGuardPageName);
94}
95
96size_t GuardedPoolAllocator::getPlatformPageSize() {
97 return sysconf(_SC_PAGESIZE);
98}
99
100void GuardedPoolAllocator::installAtFork() {
101 static bool AtForkInstalled = false;
102 if (AtForkInstalled)
103 return;
104 AtForkInstalled = true;
105 auto Disable = []() {
106 if (auto *S = getSingleton())
107 S->disable();
108 };
109 auto Enable = []() {
110 if (auto *S = getSingleton())
111 S->enable();
112 };
113 pthread_atfork(prepare: Disable, parent: Enable, child: Enable);
114}
115} // namespace gwp_asan
116

source code of compiler-rt/lib/gwp_asan/platform_specific/guarded_pool_allocator_posix.cpp