unix: handle MSG_PEEK on receive.

fix #18653

Change-Id: Ideaba943644481ffd6cf3e1801069508b7362c9a
Reviewed-on: https://review.haiku-os.org/c/haiku/+/9860
Reviewed-by: Jérôme Duval <[email protected]>

src/add-ons/kernel/network/protocols/unix/UnixDatagramEndpoint.cpp

@@ -327,7 +327,7 @@ UnixDatagramEndpoint::Receive(const iovec* vecs, size_t vecCount,
 	TRACE("[%" B_PRId32 "] %p->UnixDatagramEndpoint::Receive()\n",
 		find_thread(NULL), this);
 
-	if ((flags & ~(MSG_DONTWAIT)) != 0)
+	if ((flags & ~(MSG_DONTWAIT | MSG_PEEK)) != 0)
 		return EOPNOTSUPP;
 
 	bigtime_t timeout = 0;
@@ -370,7 +370,8 @@ UnixDatagramEndpoint::Receive(const iovec* vecs, size_t vecCount,
 
 	struct sockaddr_storage addressStorage;
 
-	ssize_t result = fifo->Read(vecs, vecCount, _ancillaryData, &addressStorage, timeout);
+	ssize_t result = fifo->Read(vecs, vecCount, _ancillaryData, &addressStorage, timeout,
+		(flags & MSG_PEEK) != 0);
 
 	// Notify select()ing writers, if we successfully read anything.
 	size_t writable = fifo->Writable();

src/add-ons/kernel/network/protocols/unix/UnixFifo.cpp

@@ -25,7 +25,7 @@
 
 UnixRequest::UnixRequest(const iovec* vecs, size_t count,
 		ancillary_data_container* ancillaryData,
-		struct sockaddr_storage* address)
+		struct sockaddr_storage* address, bool clone)
 	:
 	fVecs(vecs),
 	fVecCount(count),
@@ -34,7 +34,8 @@ UnixRequest::UnixRequest(const iovec* vecs, size_t count,
 	fBytesTransferred(0),
 	fVecIndex(0),
 	fVecOffset(0),
-	fAddress(address)
+	fAddress(address),
+	fClone(clone)
 {
 	for (size_t i = 0; i < fVecCount; i++)
 		fTotalSize += fVecs[i].iov_len;
@@ -94,6 +95,19 @@ UnixRequest::AddAncillaryData(ancillary_data_container* data)
 }
 
 
+status_t
+UnixRequest::CloneAncillaryData(ancillary_data_container* data)
+{
+	if (fAncillaryData == NULL) {
+		fAncillaryData = gStackModule->create_ancillary_data_container();
+		if (fAncillaryData == NULL)
+			return B_NO_MEMORY;
+	}
+
+	return gStackModule->clone_ancillary_data(data, fAncillaryData);
+}
+
+
 // #pragma mark - UnixBufferQueue
 
 
@@ -147,6 +161,7 @@ UnixBufferQueue::Read(UnixRequest& request)
 	bool user = gStackModule->is_syscall();
 
 	size_t readable = Readable();
+	const bool clone = request.IsClone();
 	void* data;
 	size_t size;
 
@@ -168,19 +183,31 @@ UnixBufferQueue::Read(UnixRequest& request)
 			size = readable;
 
 		ssize_t bytesRead;
-		if (user)
-			bytesRead = ring_buffer_user_read(fBuffer, (uint8*)data, size);
-		else
-			bytesRead = ring_buffer_read(fBuffer, (uint8*)data, size);
-
+		if (user) {
+			if (clone) {
+				bytesRead = ring_buffer_user_peek(fBuffer, request.BytesTransferred(),
+					(uint8*)data, size);
+			} else {
+				bytesRead = ring_buffer_user_read(fBuffer, (uint8*)data, size);
+			}
+		} else {
+			if (clone) {
+				bytesRead = ring_buffer_peek(fBuffer, request.BytesTransferred(),
+					(uint8*)data, size);
+			} else {
+				bytesRead = ring_buffer_read(fBuffer, (uint8*)data, size);
+			}
+		}
 		if (bytesRead < 0)
 			return bytesRead;
 		if (bytesRead == 0)
 			return B_ERROR;
 
-		// Adjust ancillary data entry offsets, respectively attach the ones
-		// that belong to the read data to the request.
-		if (AncillaryDataEntry* entry = fAncillaryData.Head()) {
+		if (clone) {
+			// Clone ancillary data afterwards
+		} else if (AncillaryDataEntry* entry = fAncillaryData.Head()) {
+			// Adjust ancillary data entry offsets, respectively attach the ones
+			// that belong to the read data to the request.
 			size_t offsetDelta = bytesRead;
 			while (entry != NULL && offsetDelta > entry->offset) {
 				// entry data have been read -- add ancillary data to request
@@ -200,7 +227,7 @@ UnixBufferQueue::Read(UnixRequest& request)
 		readable -= bytesRead;
 	}
 
-	if (fType == UnixFifoType::Datagram) {
+	if (!clone && fType == UnixFifoType::Datagram) {
 		fDatagrams.RemoveHead();
 
 		if (request.Address() != NULL)
@@ -228,6 +255,18 @@ UnixBufferQueue::Read(UnixRequest& request)
 		}
 	}
 
+	if (clone) {
+		AncillaryDataEntry* entry = fAncillaryData.Head();
+		size_t offsetDelta = request.BytesTransferred();
+		while (entry != NULL && offsetDelta > entry->offset) {
+			request.CloneAncillaryData(entry->data);
+			entry = fAncillaryData.GetNext(entry);
+		}
+		if (fType == UnixFifoType::Datagram && request.Address() != NULL)
+			memcpy(request.Address(), &datagramEntry->address, sizeof(datagramEntry->address));
+	}
+
+
 	return B_OK;
 }
 
@@ -389,15 +428,15 @@ UnixFifo::Shutdown(uint32 shutdown)
 ssize_t
 UnixFifo::Read(const iovec* vecs, size_t vecCount,
 	ancillary_data_container** _ancillaryData,
-	struct sockaddr_storage* address, bigtime_t timeout)
+	struct sockaddr_storage* address, bigtime_t timeout, bool peek)
 {
-	TRACE("[%" B_PRId32 "] %p->UnixFifo::Read(%p, %ld, %" B_PRIdBIGTIME ")\n",
-		find_thread(NULL), this, vecs, vecCount, timeout);
+	TRACE("[%" B_PRId32 "] %p->UnixFifo::Read(%p, %ld, %" B_PRIdBIGTIME ") %d\n",
+		find_thread(NULL), this, vecs, vecCount, timeout, peek);
 
 	if (IsReadShutdown() && fBuffer.Readable() == 0)
 		RETURN_ERROR(UNIX_FIFO_SHUTDOWN);
 
-	UnixRequest request(vecs, vecCount, NULL, address);
+	UnixRequest request(vecs, vecCount, NULL, address, peek);
 	fReaders.Add(&request);
 	fReadRequested += request.TotalSize();
 

src/add-ons/kernel/network/protocols/unix/UnixFifo.h

@@ -37,7 +37,7 @@ class UnixRequest : public DoublyLinkedListLinkImpl<UnixRequest> {
 public:
 	UnixRequest(const iovec* vecs, size_t count,
 			ancillary_data_container* ancillaryData,
-			struct sockaddr_storage* address);
+			struct sockaddr_storage* address, bool clone = false);
 
 	off_t TotalSize() const			{ return fTotalSize; }
 	off_t BytesTransferred() const	{ return fBytesTransferred; }
@@ -48,9 +48,11 @@ public:
 
 	ancillary_data_container* AncillaryData() const	 { return fAncillaryData; }
 	void AddAncillaryData(ancillary_data_container* data);
+	status_t CloneAncillaryData(ancillary_data_container* data);
 	void UnsetAncillaryData();
 
 	struct sockaddr_storage* Address() const	{ return fAddress; }
+	bool IsClone() const			{ return fClone; }
 
 private:
 	const iovec*					fVecs;
@@ -61,6 +63,7 @@ private:
 	size_t							fVecIndex;
 	size_t							fVecOffset;
 	struct sockaddr_storage*		fAddress;
+	bool							fClone;
 };
 
 
@@ -134,7 +137,7 @@ public:
 
 	ssize_t Read(const iovec* vecs, size_t vecCount,
 		ancillary_data_container** _ancillaryData,
-		struct sockaddr_storage* address, bigtime_t timeout);
+		struct sockaddr_storage* address, bigtime_t timeout, bool peek);
 	ssize_t Write(const iovec* vecs, size_t vecCount,
 		ancillary_data_container* ancillaryData,
 		const struct sockaddr_storage* address, bigtime_t timeout);

src/add-ons/kernel/network/protocols/unix/UnixStreamEndpoint.cpp

@@ -483,7 +483,7 @@ UnixStreamEndpoint::Receive(const iovec* vecs, size_t vecCount,
 		find_thread(NULL), this, vecs, vecCount);
 
 	// TODO: handle MSG_WAITALL
-	if ((flags & ~(MSG_DONTWAIT | MSG_WAITALL)) != 0)
+	if ((flags & ~(MSG_DONTWAIT | MSG_PEEK | MSG_WAITALL)) != 0)
 		return EOPNOTSUPP;
 
 	bigtime_t timeout = 0;
@@ -521,7 +521,8 @@ UnixStreamEndpoint::Receive(const iovec* vecs, size_t vecCount,
 	// unlock endpoint
 	locker.Unlock();
 
-	ssize_t result = fifo->Read(vecs, vecCount, _ancillaryData, NULL, timeout);
+	ssize_t result = fifo->Read(vecs, vecCount, _ancillaryData, NULL, timeout,
+		(flags & MSG_PEEK) != 0);
 
 	// Notify select()ing writers, if we successfully read anything.
 	size_t writable = fifo->Writable();

src/add-ons/kernel/network/protocols/unix/unix.cpp

@@ -60,6 +60,21 @@ destroy_scm_rights_descriptors(const ancillary_data_header* header,
 }
 
 
+void
+clone_scm_rights_descriptors(const ancillary_data_header* header, void* data)
+{
+	int count = header->len / sizeof(file_descriptor*);
+	file_descriptor** descriptors = (file_descriptor**)data;
+
+	for (int i = 0; i < count; i++) {
+		if (descriptors[i] != NULL) {
+			inc_fd_ref_count(descriptors[i]);
+			inc_fd_open_count(descriptors[i]);
+		}
+	}
+}
+
+
 // #pragma mark -
 
 
@@ -334,7 +349,7 @@ unix_add_ancillary_data(net_protocol *self, ancillary_data_container *container,
 			"container\n", find_thread(NULL), count);
 
 		error = gStackModule->add_ancillary_data(container, &header,
-			descriptors, destroy_scm_rights_descriptors, NULL, NULL);
+			descriptors, destroy_scm_rights_descriptors, clone_scm_rights_descriptors, NULL);
 	}
 
 	// cleanup on error