1 // Copyright 2017 The Fuchsia Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include <lib/fidl/coding.h>
6
7 #include <stdalign.h>
8 #include <stdint.h>
9 #include <stdlib.h>
10
11 #include <lib/fidl/internal.h>
12 #include <zircon/assert.h>
13 #include <zircon/compiler.h>
14
15 #ifdef __Fuchsia__
16 #include <zircon/syscalls.h>
17 #endif
18
19 #include "buffer_walker.h"
20
21 // TODO(kulakowski) Design zx_status_t error values.
22
23 namespace {
24
25 class FidlDecoder final : public fidl::internal::BufferWalker<FidlDecoder, true, false> {
26 typedef fidl::internal::BufferWalker<FidlDecoder, true, false> Super;
27
28 public:
FidlDecoder(const fidl_type_t * type,void * bytes,uint32_t num_bytes,const zx_handle_t * handles,uint32_t num_handles,const char ** out_error_msg)29 FidlDecoder(const fidl_type_t* type, void* bytes, uint32_t num_bytes,
30 const zx_handle_t* handles, uint32_t num_handles, const char** out_error_msg)
31 : Super(type), bytes_(static_cast<uint8_t*>(bytes)), num_bytes_(num_bytes),
32 handles_(handles), num_handles_(num_handles), out_error_msg_(out_error_msg) {}
33
Walk()34 void Walk() {
35 if (handles_ == nullptr && num_handles_ != 0u) {
36 SetError("Cannot provide non-zero handle count and null handle pointer");
37 return;
38 }
39 Super::Walk();
40 if (status_ == ZX_OK && handle_idx() != num_handles()) {
41 SetError("message did not contain the specified number of handles");
42 }
43 }
44
bytes() const45 uint8_t* bytes() const { return bytes_; }
num_bytes() const46 uint32_t num_bytes() const { return num_bytes_; }
num_handles() const47 uint32_t num_handles() const { return num_handles_; }
48
ValidateOutOfLineStorageClaim(const void * a,const void * b)49 bool ValidateOutOfLineStorageClaim(const void* a, const void* b) {
50 return true;
51 }
52
UnclaimedHandle(zx_handle_t * out_handle)53 void UnclaimedHandle(zx_handle_t* out_handle) {}
ClaimedHandle(zx_handle_t * out_handle,uint32_t idx)54 void ClaimedHandle(zx_handle_t* out_handle, uint32_t idx) {
55 if (out_handle != nullptr) {
56 *out_handle = handles_[idx];
57 #ifdef __Fuchsia__
58 } else {
59 // Return value intentionally ignored: this is best-effort cleanup.
60 zx_handle_close(handles_[idx]);
61 #endif
62 }
63 }
64
GetPointerState(const void * ptr) const65 PointerState GetPointerState(const void* ptr) const {
66 return static_cast<PointerState>(*static_cast<const uintptr_t*>(ptr));
67 }
GetHandleState(zx_handle_t p) const68 HandleState GetHandleState(zx_handle_t p) const {
69 return static_cast<HandleState>(p);
70 }
71
72 template <class T>
UpdatePointer(T * p,T v)73 void UpdatePointer(T* p, T v) {
74 *p = v;
75 }
76
SetError(const char * error_msg)77 void SetError(const char* error_msg) {
78 status_ = ZX_ERR_INVALID_ARGS;
79 if (out_error_msg_ != nullptr) {
80 *out_error_msg_ = error_msg;
81 }
82 #ifdef __Fuchsia__
83 if (handles_) {
84 // Return value intentionally ignored: this is best-effort cleanup.
85 zx_handle_close_many(handles_, num_handles());
86 }
87 #endif
88 }
89
status() const90 zx_status_t status() const { return status_; }
91
92 private:
93 uint8_t* const bytes_;
94 const uint32_t num_bytes_;
95 const zx_handle_t* const handles_;
96 const uint32_t num_handles_;
97 const char** const out_error_msg_;
98 zx_status_t status_ = ZX_OK;
99 };
100
101 } // namespace
102
fidl_decode(const fidl_type_t * type,void * bytes,uint32_t num_bytes,const zx_handle_t * handles,uint32_t num_handles,const char ** out_error_msg)103 zx_status_t fidl_decode(const fidl_type_t* type, void* bytes, uint32_t num_bytes,
104 const zx_handle_t* handles, uint32_t num_handles,
105 const char** out_error_msg) {
106 FidlDecoder decoder(type, bytes, num_bytes, handles, num_handles, out_error_msg);
107 decoder.Walk();
108 return decoder.status();
109 }
110
fidl_decode_msg(const fidl_type_t * type,fidl_msg_t * msg,const char ** out_error_msg)111 zx_status_t fidl_decode_msg(const fidl_type_t* type, fidl_msg_t* msg,
112 const char** out_error_msg) {
113 return fidl_decode(type, msg->bytes, msg->num_bytes, msg->handles,
114 msg->num_handles, out_error_msg);
115 }
116