1 //===-- fuchsia.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 "platform.h"
10
11 #if SCUDO_FUCHSIA
12
13 #include "common.h"
14 #include "mutex.h"
15 #include "string_utils.h"
16
17 #include <lib/sync/mutex.h> // for sync_mutex_t
18 #include <stdlib.h> // for getenv()
19 #include <zircon/compiler.h>
20 #include <zircon/process.h>
21 #include <zircon/sanitizer.h>
22 #include <zircon/status.h>
23 #include <zircon/syscalls.h>
24
25 namespace scudo {
26
getPageSize()27 uptr getPageSize() { return _zx_system_get_page_size(); }
28
die()29 void NORETURN die() { __builtin_trap(); }
30
31 // We zero-initialize the Extra parameter of map(), make sure this is consistent
32 // with ZX_HANDLE_INVALID.
33 static_assert(ZX_HANDLE_INVALID == 0, "");
34
dieOnError(zx_status_t Status,const char * FnName,uptr Size)35 static void NORETURN dieOnError(zx_status_t Status, const char *FnName,
36 uptr Size) {
37 char Error[128];
38 formatString(Error, sizeof(Error),
39 "SCUDO ERROR: %s failed with size %zuKB (%s)", FnName,
40 Size >> 10, zx_status_get_string(Status));
41 outputRaw(Error);
42 die();
43 }
44
allocateVmar(uptr Size,MapPlatformData * Data,bool AllowNoMem)45 static void *allocateVmar(uptr Size, MapPlatformData *Data, bool AllowNoMem) {
46 // Only scenario so far.
47 DCHECK(Data);
48 DCHECK_EQ(Data->Vmar, ZX_HANDLE_INVALID);
49
50 const zx_status_t Status = _zx_vmar_allocate(
51 _zx_vmar_root_self(),
52 ZX_VM_CAN_MAP_READ | ZX_VM_CAN_MAP_WRITE | ZX_VM_CAN_MAP_SPECIFIC, 0,
53 Size, &Data->Vmar, &Data->VmarBase);
54 if (UNLIKELY(Status != ZX_OK)) {
55 if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
56 dieOnError(Status, "zx_vmar_allocate", Size);
57 return nullptr;
58 }
59 return reinterpret_cast<void *>(Data->VmarBase);
60 }
61
map(void * Addr,uptr Size,const char * Name,uptr Flags,MapPlatformData * Data)62 void *map(void *Addr, uptr Size, const char *Name, uptr Flags,
63 MapPlatformData *Data) {
64 DCHECK_EQ(Size % getPageSizeCached(), 0);
65 const bool AllowNoMem = !!(Flags & MAP_ALLOWNOMEM);
66
67 // For MAP_NOACCESS, just allocate a Vmar and return.
68 if (Flags & MAP_NOACCESS)
69 return allocateVmar(Size, Data, AllowNoMem);
70
71 const zx_handle_t Vmar = (Data && Data->Vmar != ZX_HANDLE_INVALID)
72 ? Data->Vmar
73 : _zx_vmar_root_self();
74
75 zx_status_t Status;
76 zx_handle_t Vmo;
77 uint64_t VmoSize = 0;
78 if (Data && Data->Vmo != ZX_HANDLE_INVALID) {
79 // If a Vmo was specified, it's a resize operation.
80 CHECK(Addr);
81 DCHECK(Flags & MAP_RESIZABLE);
82 Vmo = Data->Vmo;
83 VmoSize = Data->VmoSize;
84 Status = _zx_vmo_set_size(Vmo, VmoSize + Size);
85 if (Status != ZX_OK) {
86 if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
87 dieOnError(Status, "zx_vmo_set_size", VmoSize + Size);
88 return nullptr;
89 }
90 } else {
91 // Otherwise, create a Vmo and set its name.
92 Status = _zx_vmo_create(Size, ZX_VMO_RESIZABLE, &Vmo);
93 if (UNLIKELY(Status != ZX_OK)) {
94 if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
95 dieOnError(Status, "zx_vmo_create", Size);
96 return nullptr;
97 }
98 _zx_object_set_property(Vmo, ZX_PROP_NAME, Name, strlen(Name));
99 }
100
101 uintptr_t P;
102 zx_vm_option_t MapFlags =
103 ZX_VM_PERM_READ | ZX_VM_PERM_WRITE | ZX_VM_ALLOW_FAULTS;
104 if (Addr)
105 DCHECK(Data);
106 const uint64_t Offset =
107 Addr ? reinterpret_cast<uintptr_t>(Addr) - Data->VmarBase : 0;
108 if (Offset)
109 MapFlags |= ZX_VM_SPECIFIC;
110 Status = _zx_vmar_map(Vmar, MapFlags, Offset, Vmo, VmoSize, Size, &P);
111 if (UNLIKELY(Status != ZX_OK)) {
112 if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
113 dieOnError(Status, "zx_vmar_map", Size);
114 return nullptr;
115 }
116
117 if (Flags & MAP_PRECOMMIT) {
118 Status = _zx_vmar_op_range(Vmar, ZX_VMAR_OP_COMMIT, P, Size,
119 /*buffer=*/nullptr, /*buffer_size=*/0);
120 }
121
122 // No need to track the Vmo if we don't intend on resizing it. Close it.
123 if (Flags & MAP_RESIZABLE) {
124 DCHECK(Data);
125 if (Data->Vmo == ZX_HANDLE_INVALID)
126 Data->Vmo = Vmo;
127 else
128 DCHECK_EQ(Data->Vmo, Vmo);
129 } else {
130 CHECK_EQ(_zx_handle_close(Vmo), ZX_OK);
131 }
132 if (UNLIKELY(Status != ZX_OK)) {
133 if (Status != ZX_ERR_NO_MEMORY || !AllowNoMem)
134 dieOnError(Status, "zx_vmar_op_range", Size);
135 return nullptr;
136 }
137
138 if (Data)
139 Data->VmoSize += Size;
140
141 return reinterpret_cast<void *>(P);
142 }
143
unmap(void * Addr,uptr Size,uptr Flags,MapPlatformData * Data)144 void unmap(void *Addr, uptr Size, uptr Flags, MapPlatformData *Data) {
145 if (Flags & UNMAP_ALL) {
146 DCHECK_NE(Data, nullptr);
147 const zx_handle_t Vmar = Data->Vmar;
148 DCHECK_NE(Vmar, _zx_vmar_root_self());
149 // Destroying the vmar effectively unmaps the whole mapping.
150 CHECK_EQ(_zx_vmar_destroy(Vmar), ZX_OK);
151 CHECK_EQ(_zx_handle_close(Vmar), ZX_OK);
152 } else {
153 const zx_handle_t Vmar = (Data && Data->Vmar != ZX_HANDLE_INVALID)
154 ? Data->Vmar
155 : _zx_vmar_root_self();
156 const zx_status_t Status =
157 _zx_vmar_unmap(Vmar, reinterpret_cast<uintptr_t>(Addr), Size);
158 if (UNLIKELY(Status != ZX_OK))
159 dieOnError(Status, "zx_vmar_unmap", Size);
160 }
161 if (Data) {
162 if (Data->Vmo != ZX_HANDLE_INVALID)
163 CHECK_EQ(_zx_handle_close(Data->Vmo), ZX_OK);
164 memset(Data, 0, sizeof(*Data));
165 }
166 }
167
setMemoryPermission(UNUSED uptr Addr,UNUSED uptr Size,UNUSED uptr Flags,UNUSED MapPlatformData * Data)168 void setMemoryPermission(UNUSED uptr Addr, UNUSED uptr Size, UNUSED uptr Flags,
169 UNUSED MapPlatformData *Data) {
170 const zx_vm_option_t Prot =
171 (Flags & MAP_NOACCESS) ? 0 : (ZX_VM_PERM_READ | ZX_VM_PERM_WRITE);
172 DCHECK(Data);
173 DCHECK_NE(Data->Vmar, ZX_HANDLE_INVALID);
174 const zx_status_t Status = _zx_vmar_protect(Data->Vmar, Prot, Addr, Size);
175 if (Status != ZX_OK)
176 dieOnError(Status, "zx_vmar_protect", Size);
177 }
178
releasePagesToOS(UNUSED uptr BaseAddress,uptr Offset,uptr Size,MapPlatformData * Data)179 void releasePagesToOS(UNUSED uptr BaseAddress, uptr Offset, uptr Size,
180 MapPlatformData *Data) {
181 // TODO: DCHECK the BaseAddress is consistent with the data in
182 // MapPlatformData.
183 DCHECK(Data);
184 DCHECK_NE(Data->Vmar, ZX_HANDLE_INVALID);
185 DCHECK_NE(Data->Vmo, ZX_HANDLE_INVALID);
186 const zx_status_t Status =
187 _zx_vmo_op_range(Data->Vmo, ZX_VMO_OP_DECOMMIT, Offset, Size, NULL, 0);
188 CHECK_EQ(Status, ZX_OK);
189 }
190
getEnv(const char * Name)191 const char *getEnv(const char *Name) { return getenv(Name); }
192
193 // Note: we need to flag these methods with __TA_NO_THREAD_SAFETY_ANALYSIS
194 // because the Fuchsia implementation of sync_mutex_t has clang thread safety
195 // annotations. Were we to apply proper capability annotations to the top level
196 // HybridMutex class itself, they would not be needed. As it stands, the
197 // thread analysis thinks that we are locking the mutex and accidentally leaving
198 // it locked on the way out.
tryLock()199 bool HybridMutex::tryLock() __TA_NO_THREAD_SAFETY_ANALYSIS {
200 // Size and alignment must be compatible between both types.
201 return sync_mutex_trylock(&M) == ZX_OK;
202 }
203
lockSlow()204 void HybridMutex::lockSlow() __TA_NO_THREAD_SAFETY_ANALYSIS {
205 sync_mutex_lock(&M);
206 }
207
unlock()208 void HybridMutex::unlock() __TA_NO_THREAD_SAFETY_ANALYSIS {
209 sync_mutex_unlock(&M);
210 }
211
assertHeldImpl()212 void HybridMutex::assertHeldImpl() __TA_NO_THREAD_SAFETY_ANALYSIS {}
213
getMonotonicTime()214 u64 getMonotonicTime() { return _zx_clock_get_monotonic(); }
getMonotonicTimeFast()215 u64 getMonotonicTimeFast() { return _zx_clock_get_monotonic(); }
216
getNumberOfCPUs()217 u32 getNumberOfCPUs() { return _zx_system_get_num_cpus(); }
218
getThreadID()219 u32 getThreadID() { return 0; }
220
getRandom(void * Buffer,uptr Length,UNUSED bool Blocking)221 bool getRandom(void *Buffer, uptr Length, UNUSED bool Blocking) {
222 static_assert(MaxRandomLength <= ZX_CPRNG_DRAW_MAX_LEN, "");
223 if (UNLIKELY(!Buffer || !Length || Length > MaxRandomLength))
224 return false;
225 _zx_cprng_draw(Buffer, Length);
226 return true;
227 }
228
outputRaw(const char * Buffer)229 void outputRaw(const char *Buffer) {
230 __sanitizer_log_write(Buffer, strlen(Buffer));
231 }
232
setAbortMessage(const char * Message)233 void setAbortMessage(const char *Message) {}
234
235 } // namespace scudo
236
237 #endif // SCUDO_FUCHSIA
238