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