Add FuseMessage::WriteWithBody function
The funciton is going to be used to write FUSE header with external
body.
Bug: 35229514
Test: libappfuse_tests
Change-Id: I303022b555deca960b8e08f26140a5ef10133efe
diff --git a/libappfuse/FuseBuffer.cc b/libappfuse/FuseBuffer.cc
index 13cfc88..5bc5497 100644
--- a/libappfuse/FuseBuffer.cc
+++ b/libappfuse/FuseBuffer.cc
@@ -24,6 +24,7 @@
#include <type_traits>
#include <sys/socket.h>
+#include <sys/uio.h>
#include <android-base/file.h>
#include <android-base/logging.h>
@@ -34,9 +35,9 @@
namespace {
template <typename T>
-bool CheckHeaderLength(const FuseMessage<T>* self, const char* name) {
+bool CheckHeaderLength(const FuseMessage<T>* self, const char* name, size_t max_size) {
const auto& header = static_cast<const T*>(self)->header;
- if (header.len >= sizeof(header) && header.len <= sizeof(T)) {
+ if (header.len >= sizeof(header) && header.len <= max_size) {
return true;
} else {
LOG(ERROR) << "Invalid header length is found in " << name << ": " << header.len;
@@ -68,7 +69,7 @@
return ResultOrAgain::kFailure;
}
- if (!CheckHeaderLength<T>(self, "Read")) {
+ if (!CheckHeaderLength<T>(self, "Read", sizeof(T))) {
return ResultOrAgain::kFailure;
}
@@ -81,15 +82,26 @@
}
template <typename T>
-ResultOrAgain WriteInternal(const FuseMessage<T>* self, int fd, int sockflag) {
- if (!CheckHeaderLength<T>(self, "Write")) {
+ResultOrAgain WriteInternal(const FuseMessage<T>* self, int fd, int sockflag, const void* data,
+ size_t max_size) {
+ if (!CheckHeaderLength<T>(self, "Write", max_size)) {
return ResultOrAgain::kFailure;
}
const char* const buf = reinterpret_cast<const char*>(self);
const auto& header = static_cast<const T*>(self)->header;
- const int result = sockflag ? TEMP_FAILURE_RETRY(send(fd, buf, header.len, sockflag))
- : TEMP_FAILURE_RETRY(write(fd, buf, header.len));
+
+ int result;
+ if (sockflag) {
+ CHECK(data == nullptr);
+ result = TEMP_FAILURE_RETRY(send(fd, buf, header.len, sockflag));
+ } else if (data) {
+ const struct iovec vec[] = {{const_cast<char*>(buf), sizeof(header)},
+ {const_cast<void*>(data), header.len - sizeof(header)}};
+ result = TEMP_FAILURE_RETRY(writev(fd, vec, arraysize(vec)));
+ } else {
+ result = TEMP_FAILURE_RETRY(write(fd, buf, header.len));
+ }
if (result == -1) {
if (errno == EAGAIN) {
@@ -143,17 +155,20 @@
template <typename T>
bool FuseMessage<T>::Write(int fd) const {
- return WriteInternal(this, fd, 0) == ResultOrAgain::kSuccess;
+ return WriteInternal(this, fd, 0, nullptr, sizeof(T)) == ResultOrAgain::kSuccess;
+}
+
+template <typename T>
+bool FuseMessage<T>::WriteWithBody(int fd, size_t max_size, const void* data) const {
+ CHECK(data != nullptr);
+ return WriteInternal<T>(this, fd, 0, data, max_size) == ResultOrAgain::kSuccess;
}
template <typename T>
ResultOrAgain FuseMessage<T>::WriteOrAgain(int fd) const {
- return WriteInternal(this, fd, MSG_DONTWAIT);
+ return WriteInternal(this, fd, MSG_DONTWAIT, nullptr, sizeof(T));
}
-template class FuseMessage<FuseRequest>;
-template class FuseMessage<FuseResponse>;
-
void FuseRequest::Reset(
uint32_t data_length, uint32_t opcode, uint64_t unique) {
memset(this, 0, sizeof(fuse_in_header) + data_length);
@@ -162,17 +177,18 @@
header.unique = unique;
}
-void FuseResponse::ResetHeader(
- uint32_t data_length, int32_t error, uint64_t unique) {
- CHECK_LE(error, 0) << "error should be zero or negative.";
- header.len = sizeof(fuse_out_header) + data_length;
- header.error = error;
- header.unique = unique;
+template <size_t N>
+void FuseResponseBase<N>::ResetHeader(uint32_t data_length, int32_t error, uint64_t unique) {
+ CHECK_LE(error, 0) << "error should be zero or negative.";
+ header.len = sizeof(fuse_out_header) + data_length;
+ header.error = error;
+ header.unique = unique;
}
-void FuseResponse::Reset(uint32_t data_length, int32_t error, uint64_t unique) {
- memset(this, 0, sizeof(fuse_out_header) + data_length);
- ResetHeader(data_length, error, unique);
+template <size_t N>
+void FuseResponseBase<N>::Reset(uint32_t data_length, int32_t error, uint64_t unique) {
+ memset(this, 0, sizeof(fuse_out_header) + data_length);
+ ResetHeader(data_length, error, unique);
}
void FuseBuffer::HandleInit() {
@@ -222,5 +238,11 @@
response.Reset(0, -ENOSYS, unique);
}
+template class FuseMessage<FuseRequest>;
+template class FuseMessage<FuseResponse>;
+template class FuseMessage<FuseSimpleResponse>;
+template struct FuseResponseBase<0u>;
+template struct FuseResponseBase<kFuseMaxRead>;
+
} // namespace fuse
} // namespace android
diff --git a/libappfuse/include/libappfuse/FuseBuffer.h b/libappfuse/include/libappfuse/FuseBuffer.h
index fbb05d6..7a70bf3 100644
--- a/libappfuse/include/libappfuse/FuseBuffer.h
+++ b/libappfuse/include/libappfuse/FuseBuffer.h
@@ -43,11 +43,9 @@
public:
bool Read(int fd);
bool Write(int fd) const;
+ bool WriteWithBody(int fd, size_t max_size, const void* data) const;
ResultOrAgain ReadOrAgain(int fd);
ResultOrAgain WriteOrAgain(int fd) const;
-
-private:
- bool CheckHeaderLength(const char* name) const;
};
// FuseRequest represents file operation requests from /dev/fuse. It starts
@@ -74,26 +72,30 @@
// FuseResponse represents file operation responses to /dev/fuse. It starts
// from fuse_out_header. The body layout depends on the operation code.
-struct FuseResponse : public FuseMessage<FuseResponse> {
- fuse_out_header header;
- union {
- // for FUSE_INIT
- fuse_init_out init_out;
- // for FUSE_LOOKUP
- fuse_entry_out entry_out;
- // for FUSE_GETATTR
- fuse_attr_out attr_out;
- // for FUSE_OPEN
- fuse_open_out open_out;
- // for FUSE_READ
- char read_data[kFuseMaxRead];
- // for FUSE_WRITE
- fuse_write_out write_out;
- };
- void Reset(uint32_t data_length, int32_t error, uint64_t unique);
- void ResetHeader(uint32_t data_length, int32_t error, uint64_t unique);
+template <size_t N>
+struct FuseResponseBase : public FuseMessage<FuseResponseBase<N>> {
+ fuse_out_header header;
+ union {
+ // for FUSE_INIT
+ fuse_init_out init_out;
+ // for FUSE_LOOKUP
+ fuse_entry_out entry_out;
+ // for FUSE_GETATTR
+ fuse_attr_out attr_out;
+ // for FUSE_OPEN
+ fuse_open_out open_out;
+ // for FUSE_READ
+ char read_data[N];
+ // for FUSE_WRITE
+ fuse_write_out write_out;
+ };
+ void Reset(uint32_t data_length, int32_t error, uint64_t unique);
+ void ResetHeader(uint32_t data_length, int32_t error, uint64_t unique);
};
+using FuseResponse = FuseResponseBase<kFuseMaxRead>;
+using FuseSimpleResponse = FuseResponseBase<0u>;
+
// To reduce memory usage, FuseBuffer shares the memory region for request and
// response.
union FuseBuffer final {