nfs4: Add read_symlink() hook

src/add-ons/kernel/file_systems/nfs4/Inode.cpp

@@ -151,6 +151,36 @@ Inode::LookUp(const char* name, ino_t* id)
 }
 
 
+status_t
+Inode::ReadLink(void* buffer, size_t* length)
+{
+	if (fType != NF4LNK)
+		return B_BAD_VALUE;
+
+	Request request(fFilesystem->Server());
+	RequestBuilder& req = request.Builder();
+
+	req.PutFH(fHandle);
+	req.ReadLink();	
+
+	status_t result = request.Send();
+	if (result != B_OK)
+		return result;
+
+	ReplyInterpreter& reply = request.Reply();
+
+	result = reply.PutFH();
+	if (result != B_OK)
+		return result;
+
+	uint32 size;
+	result = reply.ReadLink(buffer, &size, *length);
+	*length = static_cast<size_t>(size);
+
+	return result;
+}
+
+
 status_t
 Inode::Access(int mode)
 {

src/add-ons/kernel/file_systems/nfs4/Inode.h

@@ -35,6 +35,7 @@ public:
 	inline			const char*	Name() const;
 
 					status_t	LookUp(const char* name, ino_t* id);
+					status_t	ReadLink(void* buffer, size_t* length);
 					status_t	Access(int mode);
 					status_t	Stat(struct stat* st);
 

src/add-ons/kernel/file_systems/nfs4/NFS4Defs.h

@@ -33,6 +33,7 @@ enum Opcode {
 	OpPutRootFH				= 24,
 	OpRead					= 25,
 	OpReadDir				= 26,
+	OpReadLink				= 27,
 	OpRenew					= 30,
 	OpSetClientID			= 35,
 	OpSetClientIDConfirm	= 36

src/add-ons/kernel/file_systems/nfs4/ReplyInterpreter.cpp

@@ -257,6 +257,19 @@ ReplyInterpreter::ReadDir(uint64* cookie, DirEntry** dirents, uint32* _count,
 }
 
 
+status_t
+ReplyInterpreter::ReadLink(void* buffer, uint32* size, uint32 maxSize)
+{
+	status_t res = _OperationError(OpReadLink);
+	if (res != B_OK)
+		return res;
+
+	const void* ptr = fReply->Stream().GetOpaque(size);
+	memcpy(buffer, ptr, min_c(*size, maxSize));
+
+	return fReply->Stream().IsEOF() ? B_BAD_VALUE : B_OK;
+}
+
 status_t
 ReplyInterpreter::SetClientID(uint64* clientid, uint64* verifier)
 {

src/add-ons/kernel/file_systems/nfs4/ReplyInterpreter.h

@@ -58,6 +58,7 @@ public:
 			status_t	Read(void* buffer, uint32* size, bool* eof);
 			status_t	ReadDir(uint64* cookie, DirEntry** dirents,
 							uint32* count, bool* eof);
+			status_t	ReadLink(void* buffer, uint32* size, uint32 maxSize);
 	inline	status_t	Renew();
 			status_t	SetClientID(uint64* clientid, uint64* verifier);
 	inline	status_t	SetClientIDConfirm();

src/add-ons/kernel/file_systems/nfs4/RequestBuilder.cpp

@@ -286,6 +286,22 @@ RequestBuilder::ReadDir(uint32 count, uint64* cookie, Attribute* attrs,
 }
 
 
+status_t
+RequestBuilder::ReadLink()
+{
+	if (fProcedure != ProcCompound)
+		return B_BAD_VALUE;
+	if (fRequest == NULL)
+		return B_NO_MEMORY;
+
+	fRequest->Stream().AddUInt(OpReadLink);
+
+	fOpCount++;
+
+	return B_OK;
+}
+
+
 status_t
 RequestBuilder::Renew(uint64 clientId)
 {

src/add-ons/kernel/file_systems/nfs4/RequestBuilder.h

@@ -41,6 +41,7 @@ public:
 										uint64 pos, uint32 len);
 			status_t				ReadDir(uint32 count, uint64* cookie, 
 										Attribute* attrs, uint32 attrCount);
+			status_t				ReadLink();
 			status_t				Renew(uint64 clientId);
 			status_t				SetClientID(const RPC::Server* serv);
 			status_t				SetClientIDConfirm(uint64 id, uint64 ver);

src/add-ons/kernel/file_systems/nfs4/kernel_interface.cpp

@@ -145,6 +145,15 @@ nfs4_put_vnode(fs_volume* volume, fs_vnode* vnode, bool reenter)
 }
 
 
+static status_t
+nfs4_read_symlink(fs_volume* volume, fs_vnode* link, char* buffer,
+	size_t* _bufferSize)
+{
+	Inode* inode = reinterpret_cast<Inode*>(link->private_node);
+	return inode->ReadLink(buffer, _bufferSize);
+}
+
+
 static status_t
 nfs4_access(fs_volume* volume, fs_vnode* vnode, int mode)
 {
@@ -342,7 +351,7 @@ fs_vnode_ops gNFSv4VnodeOps = {
 	NULL,	// fs_deselect()
 	NULL,	// fsync()
 
-	NULL,	// read_link()
+	nfs4_read_symlink,
 	NULL,	// create_symlink()
 
 	NULL,	// link()