* Package: Added Open() (and matching Close()) method, which opens the package

file once, tracking an open count.
* Added VFSInit()/VFSUninit() methods to the Node and PackageNode class
  hierarchies, called by the {get,put}_vnode() PackageFile implements them to
  set up/tear down access to the file data. Also added a Read() reading the
  data.
* Implemented the open(), free_cookie(), and read() FS hooks for real. Reading
  files works now. Executing doesn't yet -- it requires working with
  IORequests in a way not supported by the userlandfs.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34102 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/add-ons/kernel/file_systems/packagefs/Directory.cpp

@@ -38,6 +38,19 @@ Directory::Init(Directory* parent, const char* name)
 }
 
 
+status_t
+Directory::VFSInit(dev_t deviceID)
+{
+	return B_OK;
+}
+
+
+void
+Directory::VFSUninit()
+{
+}
+
+
 mode_t
 Directory::Mode() const
 {
@@ -98,6 +111,13 @@ Directory::AddPackageNode(PackageNode* packageNode)
 }
 
 
+status_t
+Directory::Read(off_t offset, void* buffer, size_t* bufferSize)
+{
+	return B_IS_A_DIRECTORY;
+}
+
+
 void
 Directory::AddChild(Node* node)
 {

src/add-ons/kernel/file_systems/packagefs/Directory.h

@@ -31,6 +31,9 @@ public:
 
 	virtual	status_t			Init(Directory* parent, const char* name);
 
+	virtual	status_t			VFSInit(dev_t deviceID);
+	virtual	void				VFSUninit();
+
 	virtual	mode_t				Mode() const;
 	virtual	uid_t				UserID() const;
 	virtual	gid_t				GroupID() const;
@@ -39,6 +42,9 @@ public:
 
 	virtual	status_t			AddPackageNode(PackageNode* packageNode);
 
+	virtual	status_t			Read(off_t offset, void* buffer,
+									size_t* bufferSize);
+
 			void				AddChild(Node* node);
 			void				RemoveChild(Node* node);
 			Node*				FindChild(const char* name);

src/add-ons/kernel/file_systems/packagefs/LeafNode.cpp

@@ -26,6 +26,23 @@ LeafNode::Init(Directory* parent, const char* name)
 }
 
 
+status_t
+LeafNode::VFSInit(dev_t deviceID)
+{
+	if (PackageLeafNode* packageNode = fPackageNodes.Head())
+		return packageNode->VFSInit(deviceID, fID);
+	return B_OK;
+}
+
+
+void
+LeafNode::VFSUninit()
+{
+	if (PackageLeafNode* packageNode = fPackageNodes.Head())
+		packageNode->VFSUninit();
+}
+
+
 mode_t
 LeafNode::Mode() const
 {
@@ -85,6 +102,15 @@ LeafNode::AddPackageNode(PackageNode* packageNode)
 }
 
 
+status_t
+LeafNode::Read(off_t offset, void* buffer, size_t* bufferSize)
+{
+	if (PackageLeafNode* packageNode = fPackageNodes.Head())
+		return packageNode->Read(offset, buffer, bufferSize);
+	return B_ERROR;
+}
+
+
 const char*
 LeafNode::SymlinkPath() const
 {

src/add-ons/kernel/file_systems/packagefs/LeafNode.h

@@ -17,6 +17,9 @@ public:
 
 	virtual	status_t			Init(Directory* parent, const char* name);
 
+	virtual	status_t			VFSInit(dev_t deviceID);
+	virtual	void				VFSUninit();
+
 	virtual	mode_t				Mode() const;
 	virtual	uid_t				UserID() const;
 	virtual	gid_t				GroupID() const;
@@ -25,6 +28,9 @@ public:
 
 	virtual	status_t			AddPackageNode(PackageNode* packageNode);
 
+	virtual	status_t			Read(off_t offset, void* buffer,
+									size_t* bufferSize);
+
 			const char*			SymlinkPath() const;
 
 private:

src/add-ons/kernel/file_systems/packagefs/Node.h

@@ -42,6 +42,9 @@ public:
 
 	virtual	status_t			Init(Directory* parent, const char* name);
 
+	virtual	status_t			VFSInit(dev_t deviceID) = 0;
+	virtual	void				VFSUninit() = 0;
+
 	virtual	mode_t				Mode() const = 0;
 	virtual	uid_t				UserID() const = 0;
 	virtual	gid_t				GroupID() const = 0;
@@ -50,6 +53,9 @@ public:
 
 	virtual	status_t			AddPackageNode(PackageNode* packageNode) = 0;
 
+	virtual	status_t			Read(off_t offset, void* buffer,
+									size_t* bufferSize) = 0;
+
 protected:
 			rw_lock				fLock;
 			ino_t				fID;

src/add-ons/kernel/file_systems/packagefs/Package.cpp

@@ -6,19 +6,28 @@
 
 #include "Package.h"
 
+#include <errno.h>
+#include <fcntl.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
+
+#include <util/AutoLock.h>
 
 #include "DebugSupport.h"
+#include "PackageDomain.h"
 
 
 Package::Package(PackageDomain* domain, dev_t deviceID, ino_t nodeID)
 	:
 	fDomain(domain),
 	fName(NULL),
+	fFD(-1),
+	fOpenCount(0),
 	fNodeID(nodeID),
 	fDeviceID(deviceID)
 {
+	mutex_init(&fLock, "packagefs package");
 }
 
 
@@ -28,6 +37,8 @@ Package::~Package()
 		delete node;
 
 	free(fName);
+
+	mutex_destroy(&fLock);
 }
 
 
@@ -47,3 +58,55 @@ Package::AddNode(PackageNode* node)
 {
 	fNodes.Add(node);
 }
+
+
+int
+Package::Open()
+{
+	MutexLocker locker(fLock);
+	if (fOpenCount > 0) {
+		fOpenCount++;
+		return fFD;
+	}
+
+	// open the file
+	fFD = openat(fDomain->DirectoryFD(), fName, O_RDONLY);
+	if (fFD < 0) {
+		ERROR("Failed to open package file \"%s\"\n", fName);
+		return errno;
+	}
+
+	// stat it to verify that it's still the same file
+	struct stat st;
+	if (fstat(fFD, &st) < 0) {
+		ERROR("Failed to stat package file \"%s\"\n", fName);
+		close(fFD);
+		fFD = -1;
+		return errno;
+	}
+
+	if (st.st_dev != fDeviceID || st.st_ino != fNodeID) {
+		close(fFD);
+		fFD = -1;
+		RETURN_ERROR(B_ENTRY_NOT_FOUND);
+	}
+
+	fOpenCount = 1;
+	return fFD;
+}
+
+
+void
+Package::Close()
+{
+	MutexLocker locker(fLock);
+	if (fOpenCount == 0) {
+		ERROR("Package open count already 0!\n");
+		return;
+	}
+
+	if (--fOpenCount == 0) {
+		close(fFD);
+		fFD = -1;
+	}
+}

src/add-ons/kernel/file_systems/packagefs/Package.h

@@ -9,6 +9,8 @@
 #include <util/khash.h>
 #include <util/OpenHashTable.h>
 
+#include <lock.h>
+
 #include "PackageNode.h"
 
 
@@ -30,12 +32,18 @@ public:
 
 			void				AddNode(PackageNode* node);
 
+			int					Open();
+			void				Close();
+
 			const PackageNodeList&	Nodes() const
 									{ return fNodes; }
 
 private:
+			mutex				fLock;
 			PackageDomain*		fDomain;
 			char*				fName;
+			int					fFD;
+			uint32				fOpenCount;
 			Package*			fHashTableNext;
 			ino_t				fNodeID;
 			dev_t				fDeviceID;
@@ -43,6 +51,29 @@ private:
 };
 
 
+struct PackageCloser {
+	PackageCloser(Package* package)
+		:
+		fPackage(package)
+	{
+	}
+
+	~PackageCloser()
+	{
+		if (fPackage != NULL)
+			fPackage->Close();
+	}
+
+	void Detach()
+	{
+		fPackage = NULL;
+	}
+
+private:
+	Package*	fPackage;
+};
+
+
 struct PackageHashDefinition {
 	typedef const char*		KeyType;
 	typedef	Package			ValueType;

src/add-ons/kernel/file_systems/packagefs/PackageDirectory.cpp

@@ -7,9 +7,9 @@
 #include "PackageDirectory.h"
 
 
-PackageDirectory::PackageDirectory(mode_t mode)
+PackageDirectory::PackageDirectory(Package* package, mode_t mode)
 	:
-	PackageNode(mode)
+	PackageNode(package, mode)
 {
 }
 

src/add-ons/kernel/file_systems/packagefs/PackageDirectory.h

@@ -14,7 +14,7 @@
 class PackageDirectory : public PackageNode,
 	public DoublyLinkedListLinkImpl<PackageDirectory> {
 public:
-								PackageDirectory(mode_t mode);
+								PackageDirectory(Package* package, mode_t mode);
 	virtual						~PackageDirectory();
 
 			void				AddChild(PackageNode* node);

src/add-ons/kernel/file_systems/packagefs/PackageFile.cpp

@@ -6,11 +6,99 @@
 
 #include "PackageFile.h"
 
+#include <algorithm>
+#include <new>
 
-PackageFile::PackageFile(mode_t mode, const PackageData& data)
+#include <fs_cache.h>
+
+#include "DataReader.h"
+#include "PackageDataReader.h"
+
+#include "DebugSupport.h"
+#include "Package.h"
+
+
+// #pragma mark - DataAccessor
+
+
+struct PackageFile::DataAccessor {
+	DataAccessor(PackageData* data)
+		:
+		fData(data),
+		fDataReader(NULL),
+		fReader(NULL),
+		fFileCache(NULL)
+	{
+	}
+
+	~DataAccessor()
+	{
+		file_cache_delete(fFileCache);
+		delete fReader;
+		delete fDataReader;
+	}
+
+	status_t Init(dev_t deviceID, ino_t nodeID, int fd)
+	{
+		// create a DataReader for the compressed data
+		if (fData->IsEncodedInline()) {
+			fDataReader = new(std::nothrow) BufferDataReader(
+				fData->InlineData(), fData->CompressedSize());
+		} else
+			fDataReader = new(std::nothrow) FDDataReader(fd);
+
+		if (fDataReader == NULL)
+			RETURN_ERROR(B_NO_MEMORY);
+
+		// create a PackageDataReader
+		status_t error = PackageDataReaderFactory::CreatePackageDataReader(
+			fDataReader, *fData, fReader);
+		if (error != B_OK)
+			RETURN_ERROR(error);
+
+		// create a file cache
+		fFileCache = file_cache_create(deviceID, nodeID,
+			fData->UncompressedSize());
+		if (fFileCache == NULL)
+			RETURN_ERROR(B_NO_MEMORY);
+
+		return B_OK;
+	}
+
+	status_t ReadData(off_t offset, void* buffer, size_t* bufferSize)
+	{
+		if (offset < 0 || (uint64)offset > fData->UncompressedSize())
+			return B_BAD_VALUE;
+
+		size_t toRead = std::min((uint64)*bufferSize,
+			fData->UncompressedSize() - offset);
+
+		if (toRead > 0) {
+			status_t error = fReader->ReadData(offset, buffer, toRead);
+			if (error != B_OK)
+				RETURN_ERROR(error);
+		}
+
+		*bufferSize = toRead;
+		return B_OK;
+	}
+
+private:
+	PackageData*		fData;
+	DataReader*			fDataReader;
+	PackageDataReader*	fReader;
+	void*				fFileCache;
+};
+
+
+// #pragma mark - PackageFile
+
+
+PackageFile::PackageFile(Package* package, mode_t mode, const PackageData& data)
 	:
-	PackageLeafNode(mode),
-	fData(data)
+	PackageLeafNode(package, mode),
+	fData(data),
+	fDataAccessor(NULL)
 {
 }
 
@@ -20,8 +108,54 @@ PackageFile::~PackageFile()
 }
 
 
+status_t
+PackageFile::VFSInit(dev_t deviceID, ino_t nodeID)
+{
+	// open the package
+	int fd = fPackage->Open();
+	if (fd < 0)
+		RETURN_ERROR(fd);
+	PackageCloser packageCloser(fPackage);
+
+	// create the data accessor
+	fDataAccessor = new(std::nothrow) DataAccessor(&fData);
+	if (fDataAccessor == NULL)
+		RETURN_ERROR(B_NO_MEMORY);
+
+	status_t error = fDataAccessor->Init(deviceID, nodeID, fd);
+	if (error != B_OK) {
+		delete fDataAccessor;
+		fDataAccessor = NULL;
+		return error;
+	}
+
+	packageCloser.Detach();
+	return B_OK;
+}
+
+
+void
+PackageFile::VFSUninit()
+{
+	if (fDataAccessor != NULL) {
+		fPackage->Close();
+		delete fDataAccessor;
+		fDataAccessor = NULL;
+	}
+}
+
+
 off_t
 PackageFile::FileSize() const
 {
 	return fData.UncompressedSize();
 }
+
+
+status_t
+PackageFile::Read(off_t offset, void* buffer, size_t* bufferSize)
+{
+	if (fDataAccessor == NULL)
+		return B_BAD_VALUE;
+	return fDataAccessor->ReadData(offset, buffer, bufferSize);
+}

src/add-ons/kernel/file_systems/packagefs/PackageFile.h

@@ -13,14 +13,24 @@
 
 class PackageFile : public PackageLeafNode {
 public:
-								PackageFile(mode_t mode,
+								PackageFile(Package* package, mode_t mode,
 									const PackageData& data);
 	virtual						~PackageFile();
 
+	virtual	status_t			VFSInit(dev_t deviceID, ino_t nodeID);
+	virtual	void				VFSUninit();
+
 	virtual	off_t				FileSize() const;
 
+	virtual	status_t			Read(off_t offset, void* buffer,
+									size_t* bufferSize);
+
+private:
+			struct DataAccessor;
+
 private:
 			PackageData			fData;
+			DataAccessor*		fDataAccessor;
 };
 
 

src/add-ons/kernel/file_systems/packagefs/PackageLeafNode.cpp

@@ -7,9 +7,9 @@
 #include "PackageLeafNode.h"
 
 
-PackageLeafNode::PackageLeafNode(mode_t mode)
+PackageLeafNode::PackageLeafNode(Package* package, mode_t mode)
 	:
-	PackageNode(mode)
+	PackageNode(package, mode)
 {
 }
 
@@ -24,3 +24,10 @@ PackageLeafNode::SymlinkPath() const
 {
 	return NULL;
 }
+
+
+status_t
+PackageLeafNode::Read(off_t offset, void* buffer, size_t* bufferSize)
+{
+	return EBADF;
+}

src/add-ons/kernel/file_systems/packagefs/PackageLeafNode.h

@@ -14,11 +14,14 @@ class PackageData;
 
 class PackageLeafNode : public PackageNode {
 public:
-								PackageLeafNode(mode_t mode);
+								PackageLeafNode(Package* package, mode_t mode);
 	virtual						~PackageLeafNode();
 
 	virtual	const char*			SymlinkPath() const;
 
+	virtual	status_t			Read(off_t offset, void* buffer,
+									size_t* bufferSize);
+
 public:
 			SinglyLinkedListLink<PackageLeafNode> fListLink;
 };

src/add-ons/kernel/file_systems/packagefs/PackageNode.cpp

@@ -12,8 +12,9 @@
 #include "DebugSupport.h"
 
 
-PackageNode::PackageNode(mode_t mode)
+PackageNode::PackageNode(Package* package, mode_t mode)
 	:
+	fPackage(package),
 	fParent(NULL),
 	fName(NULL),
 	fMode(mode),
@@ -41,6 +42,19 @@ PackageNode::Init(PackageDirectory* parent, const char* name)
 }
 
 
+status_t
+PackageNode::VFSInit(dev_t deviceID, ino_t nodeID)
+{
+	return B_OK;
+}
+
+
+void
+PackageNode::VFSUninit()
+{
+}
+
+
 off_t
 PackageNode::FileSize() const
 {

src/add-ons/kernel/file_systems/packagefs/PackageNode.h

@@ -13,12 +13,13 @@
 #include <util/SinglyLinkedList.h>
 
 
+class Package;
 class PackageDirectory;
 
 
 class PackageNode : public SinglyLinkedListLinkImpl<PackageNode> {
 public:
-								PackageNode(mode_t mode);
+								PackageNode(Package* package, mode_t mode);
 	virtual						~PackageNode();
 
 			PackageDirectory*	Parent() const	{ return fParent; }
@@ -27,6 +28,9 @@ public:
 	virtual	status_t			Init(PackageDirectory* parent,
 									const char* name);
 
+	virtual	status_t			VFSInit(dev_t deviceID, ino_t nodeID);
+	virtual	void				VFSUninit();
+
 			mode_t				Mode() const			{ return fMode; }
 
 			uid_t				UserID() const			{ return fUserID; }
@@ -43,6 +47,7 @@ public:
 	virtual	off_t				FileSize() const;
 
 protected:
+			Package*			fPackage;
 			PackageDirectory*	fParent;
 			char*				fName;
 			mode_t				fMode;

src/add-ons/kernel/file_systems/packagefs/PackageSymlink.cpp

@@ -10,9 +10,9 @@
 #include <string.h>
 
 
-PackageSymlink::PackageSymlink(mode_t mode)
+PackageSymlink::PackageSymlink(Package* package, mode_t mode)
 	:
-	PackageLeafNode(mode),
+	PackageLeafNode(package, mode),
 	fSymlinkPath(NULL)
 {
 }

src/add-ons/kernel/file_systems/packagefs/PackageSymlink.h

@@ -11,7 +11,7 @@
 
 class PackageSymlink : public PackageLeafNode {
 public:
-								PackageSymlink(mode_t mode);
+								PackageSymlink(Package* package, mode_t mode);
 	virtual						~PackageSymlink();
 
 			status_t			SetSymlinkPath(const char* path);

src/add-ons/kernel/file_systems/packagefs/Volume.cpp

@@ -141,10 +141,11 @@ struct Volume::PackageLoaderContentHandler : PackageContentHandler {
 		PackageNode* node;
 		if (S_ISREG(mode)) {
 			// file
-			node = new(std::nothrow) PackageFile(mode, entry->Data());
+			node = new(std::nothrow) PackageFile(fPackage, mode, entry->Data());
 		} else if (S_ISLNK(mode)) {
 			// symlink
-			PackageSymlink* symlink = new(std::nothrow) PackageSymlink(mode);
+			PackageSymlink* symlink = new(std::nothrow) PackageSymlink(
+				fPackage, mode);
 			if (symlink == NULL)
 				RETURN_ERROR(B_NO_MEMORY);
 
@@ -157,7 +158,7 @@ struct Volume::PackageLoaderContentHandler : PackageContentHandler {
 			node = symlink;
 		} else if (S_ISDIR(mode)) {
 			// directory
-			node = new(std::nothrow) PackageDirectory(mode);
+			node = new(std::nothrow) PackageDirectory(fPackage, mode);
 		} else
 			RETURN_ERROR(B_BAD_DATA);
 
@@ -476,16 +477,12 @@ status_t
 Volume::_LoadPackage(Package* package)
 {
 	// open package file
-	int fd = openat(package->Domain()->DirectoryFD(), package->Name(),
-		O_RDONLY);
-	if (fd < 0) {
-		ERROR("Failed to open package file \"%s\"\n", package->Name());
-		return errno;
-	}
-// TODO: Verify that it's still the same file.
-	FDCloser fdCloser(fd);
+	int fd = package->Open();
+	if (fd < 0)
+		RETURN_ERROR(fd);
+	PackageCloser packageCloser(package);
 
-	// open package
+	// initialize package reader
 	PackageLoaderErrorOutput errorOutput(package);
 	PackageReader packageReader(&errorOutput);
 	status_t error = packageReader.Init(fd, false);

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

@@ -58,6 +58,43 @@ set_dirent_name(struct dirent* buffer, size_t bufferSize, const char* name,
 }
 
 
+static status_t
+check_access(Node* node, int mode)
+{
+	// write access requested?
+	if (mode & W_OK)
+		return B_READ_ONLY_DEVICE;
+
+	// get node permissions
+	int userPermissions = (node->Mode() & S_IRWXU) >> 6;
+	int groupPermissions = (node->Mode() & S_IRWXG) >> 3;
+	int otherPermissions = node->Mode() & S_IRWXO;
+
+	// get the permissions for this uid/gid
+	int permissions = 0;
+	uid_t uid = geteuid();
+
+	if (uid == 0) {
+		// user is root
+		// root has always read/write permission, but at least one of the
+		// X bits must be set for execute permission
+		permissions = userPermissions | groupPermissions | otherPermissions
+			| S_IROTH | S_IWOTH;
+	} else if (uid == node->UserID()) {
+		// user is node owner
+		permissions = userPermissions;
+	} else if (is_user_in_group(node->GroupID())) {
+		// user is in owning group
+		permissions = groupPermissions;
+	} else {
+		// user is one of the others
+		permissions = otherPermissions;
+	}
+
+	return (mode & ~permissions) == 0 ? B_OK : B_NOT_ALLOWED;
+}
+
+
 //	#pragma mark - Volume
 
 
@@ -171,9 +208,16 @@ packagefs_get_vnode(fs_volume* fsVolume, ino_t vnid, fs_vnode* fsNode,
 	Node* node = volume->FindNode(vnid);
 	if (node == NULL)
 		return B_ENTRY_NOT_FOUND;
-	node->AcquireReference();
+	BReference<Node> nodeReference(node);
+	volumeLocker.Unlock();
 
-	fsNode->private_node = node;
+	NodeWriteLocker nodeLocker(node);
+	status_t error = node->VFSInit(volume->ID());
+	if (error != B_OK)
+		RETURN_ERROR(error);
+	nodeLocker.Unlock();
+
+	fsNode->private_node = nodeReference.Detach();
 	fsNode->ops = &gPackageFSVnodeOps;
 	*_type = node->Mode() & S_IFMT;
 	*_flags = 0;
@@ -191,12 +235,28 @@ packagefs_put_vnode(fs_volume* fsVolume, fs_vnode* fsNode, bool reenter)
 	FUNCTION("volume: %p, node: %p\n", volume, node);
 	TOUCH(volume);
 
+	NodeWriteLocker nodeLocker(node);
+	node->VFSUninit();
+	nodeLocker.Unlock();
+
 	node->ReleaseReference();
 
 	return B_OK;
 }
 
 
+// #pragma mark - Request I/O
+
+
+#if 0
+static status_t
+packagefs_io(fs_volume* volume, fs_vnode* vnode, void* cookie,
+	io_request* request)
+{
+}
+#endif
+
+
 // #pragma mark - Nodes
 
 
@@ -238,39 +298,8 @@ packagefs_access(fs_volume* fsVolume, fs_vnode* fsNode, int mode)
 	FUNCTION("volume: %p, node: %p (%lld)\n", volume, node, node->ID());
 	TOUCH(volume);
 
-	// write access requested?
-	if (mode & W_OK)
-		return B_READ_ONLY_DEVICE;
-
 	NodeReadLocker nodeLocker(node);
-
-	// get node permissions
-	int userPermissions = (node->Mode() & S_IRWXU) >> 6;
-	int groupPermissions = (node->Mode() & S_IRWXG) >> 3;
-	int otherPermissions = node->Mode() & S_IRWXO;
-
-	// get the permissions for this uid/gid
-	int permissions = 0;
-	uid_t uid = geteuid();
-
-	if (uid == 0) {
-		// user is root
-		// root has always read/write permission, but at least one of the
-		// X bits must be set for execute permission
-		permissions = userPermissions | groupPermissions | otherPermissions
-			| S_IROTH | S_IWOTH;
-	} else if (uid == node->UserID()) {
-		// user is node owner
-		permissions = userPermissions;
-	} else if (is_user_in_group(node->GroupID())) {
-		// user is in owning group
-		permissions = groupPermissions;
-	} else {
-		// user is one of the others
-		permissions = otherPermissions;
-	}
-
-	return (mode & ~permissions) ? B_NOT_ALLOWED : B_OK;
+	return check_access(node, mode);
 }
 
 
@@ -304,6 +333,17 @@ packagefs_read_stat(fs_volume* fsVolume, fs_vnode* fsNode, struct stat* st)
 // #pragma mark - Files
 
 
+struct FileCookie {
+	int	openMode;
+
+	FileCookie(int openMode)
+		:
+		openMode(openMode)
+	{
+	}
+};
+
+
 static status_t
 packagefs_open(fs_volume* fsVolume, fs_vnode* fsNode, int openMode,
 	void** _cookie)
@@ -314,10 +354,26 @@ packagefs_open(fs_volume* fsVolume, fs_vnode* fsNode, int openMode,
 	FUNCTION("volume: %p, node: %p (%lld), openMode %#x\n", volume, node,
 		node->ID(), openMode);
 	TOUCH(volume);
-	TOUCH(node);
 
-// TODO: Implement it for real!
-	*_cookie = NULL;
+	NodeReadLocker nodeLocker(node);
+
+	// check the open mode and permissions
+	if (S_ISDIR(node->Mode()) && (openMode & O_RWMASK) != O_RDONLY)
+		return B_IS_A_DIRECTORY;
+
+	if ((openMode & O_RWMASK) != O_RDONLY)
+		return B_NOT_ALLOWED;
+
+	status_t error = check_access(node, R_OK);
+	if (error != B_OK)
+		return error;
+
+	// allocate the cookie
+	FileCookie* cookie = new(std::nothrow) FileCookie(openMode);
+	if (cookie == NULL)
+		RETURN_ERROR(B_NO_MEMORY);
+
+	*_cookie = cookie;
 
 	return B_OK;
 }
@@ -331,17 +387,40 @@ packagefs_close(fs_volume* fs, fs_vnode* _node, void* cookie)
 
 
 static status_t
-packagefs_free_cookie(fs_volume* fs, fs_vnode* _node, void* cookie)
+packagefs_free_cookie(fs_volume* fsVolume, fs_vnode* fsNode, void* _cookie)
 {
+	Volume* volume = (Volume*)fsVolume->private_volume;
+	Node* node = (Node*)fsNode->private_node;
+	FileCookie* cookie = (FileCookie*)_cookie;
+
+	FUNCTION("volume: %p, node: %p (%lld), cookie: %p\n", volume, node,
+		node->ID(), cookie);
+	TOUCH(volume);
+	TOUCH(node);
+
+	delete cookie;
+
 	return B_OK;
 }
 
 
 static status_t
-packagefs_read(fs_volume* fs, fs_vnode* _node, void* cookie, off_t pos,
-	void* buffer, size_t* bufferSize)
+packagefs_read(fs_volume* fsVolume, fs_vnode* fsNode, void* _cookie,
+	off_t offset, void* buffer, size_t* bufferSize)
 {
-	return B_UNSUPPORTED;
+	Volume* volume = (Volume*)fsVolume->private_volume;
+	Node* node = (Node*)fsNode->private_node;
+	FileCookie* cookie = (FileCookie*)_cookie;
+
+	FUNCTION("volume: %p, node: %p (%lld), cookie: %p, offset: %lld, "
+		"buffer: %p, size: %lu\n", volume, node, node->ID(), cookie, offset,
+		buffer, *bufferSize);
+	TOUCH(volume);
+
+	if ((cookie->openMode & O_RWMASK) != O_RDONLY)
+		return EBADF;
+
+	return node->Read(offset, buffer, bufferSize);
 }
 
 
@@ -635,7 +714,7 @@ fs_vnode_ops gPackageFSVnodeOps = {
 	NULL,	// read_pages,
 	NULL,	// write_pages,
 
-	NULL,	// io()
+	NULL,	// &packagefs_io,
 	NULL,	// cancel_io()
 
 	NULL,	// get_file_map,