packagefs: Fix handling of package domain paths

* The package directory path specified when mounting must be interpreted
  in the caller's I/O context. We did always interpret it in the
  kernel's I/O context, so that a relative path or a path in a chroot
  environment wouldn't work correctly. Now opening the directory is done
  in PackageDomain::Init() where we can at least guess the path's
  origin.
* We also normalize the path, though merely to get more conclusive debug
  output, since after opening the directory the path isn't used for
  anything else anymore.
* Make the "packages" mount parameter optional. If not specified, use
  the "packages" folder at our mount point.

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

@@ -15,10 +15,14 @@
 
 #include <AutoDeleter.h>
 
+#include <fs/KPath.h>
 #include <fs/node_monitor.h>
 #include <Notifications.h>
+#include <team.h>
+#include <vfs.h>
 
 #include "DebugSupport.h"
+#include "Volume.h"
 
 
 PackageDomain::PackageDomain(::Volume* volume)
@@ -55,16 +59,71 @@ PackageDomain::~PackageDomain()
 
 
 status_t
-PackageDomain::Init(const char* path)
+PackageDomain::Init(const char* path, struct stat* _st)
 {
-	fPath = strdup(path);
+	// Open the directory. We want the path be interpreted depending on from
+	// where it came (kernel or userland), but we always want a FD in the kernel
+	// I/O context. There's no VFS service method to do that for us, so we need
+	// to do that ourselves.
+	bool calledFromKernel
+		= team_get_current_team_id() == team_get_kernel_team_id();
+		// Not entirely correct, but good enough for now. The only alternative
+		// is to have that information passed in as well.
+
+	struct vnode* vnode;
+	status_t error;
+	if (path != NULL) {
+		error = vfs_get_vnode_from_path(path, calledFromKernel, &vnode);
+	} else {
+		// No path given -- use the "packages" directory at our mount point.
+		error = vfs_entry_ref_to_vnode(fVolume->MountPointDeviceID(),
+			fVolume->MountPointNodeID(), "packages", &vnode);
+	}
+	if (error != B_OK) {
+		ERROR("Failed to open package domain \"%s\"\n", strerror(error));
+		RETURN_ERROR(error);
+	}
+
+	fDirFD = vfs_open_vnode(vnode, O_RDONLY, true);
+
+	if (fDirFD < 0) {
+		ERROR("Failed to open package domain \"%s\"\n", strerror(fDirFD));
+		vfs_put_vnode(vnode);
+		RETURN_ERROR(fDirFD);
+	}
+	// Our vnode reference has been transferred to the FD.
+
+	// Is it a directory at all?
+	struct stat st;
+	if (fstat(fDirFD, &st) < 0)
+		RETURN_ERROR(errno);
+
+	fDeviceID = st.st_dev;
+	fNodeID = st.st_ino;
+
+	// get a normalized path
+	KPath normalizedPath;
+	if (normalizedPath.InitCheck() != B_OK)
+		RETURN_ERROR(normalizedPath.InitCheck());
+
+	char* normalizedPathBuffer = normalizedPath.LockBuffer();
+	error = vfs_entry_ref_to_path(fDeviceID, fNodeID, NULL,
+		normalizedPathBuffer, normalizedPath.BufferSize());
+	if (error != B_OK)
+		RETURN_ERROR(error);
+
+	fPath = strdup(normalizedPathBuffer);
 	if (fPath == NULL)
 		RETURN_ERROR(B_NO_MEMORY);
 
-	status_t error = fPackages.Init();
+	// init packages hash table
+	error = fPackages.Init();
 	if (error != B_OK)
 		return error;
 
+	if (_st != NULL)
+		*_st = st;
+
 	return B_OK;
 }
 
@@ -74,19 +133,6 @@ PackageDomain::Prepare(NotificationListener* listener)
 {
 	ObjectDeleter<NotificationListener> listenerDeleter(listener);
 
-	fDirFD = open(fPath, O_RDONLY);
-	if (fDirFD < 0) {
-		ERROR("Failed to open package domain \"%s\"\n", strerror(errno));
-		return errno;
-	}
-
-	struct stat st;
-	if (fstat(fDirFD, &st) < 0)
-		RETURN_ERROR(errno);
-
-	fDeviceID = st.st_dev;
-	fNodeID = st.st_ino;
-
 	status_t error = add_node_listener(fDeviceID, fNodeID, B_WATCH_DIRECTORY,
 		*listener);
 	if (error != B_OK)

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

@@ -13,6 +13,8 @@
 #include "Package.h"
 
 
+struct stat;
+
 class NotificationListener;
 class Volume;
 
@@ -29,7 +31,7 @@ public:
 			dev_t				DeviceID()		{ return fDeviceID; }
 			ino_t				NodeID()		{ return fNodeID; }
 
-			status_t			Init(const char* path);
+			status_t			Init(const char* path, struct stat* _st);
 			status_t			Prepare(NotificationListener* listener);
 									// takes over ownership of the listener
 

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

@@ -617,8 +617,8 @@ Volume::Mount(const char* parameterString)
 	CObjectDeleter<void, status_t> parameterHandleDeleter(parameterHandle,
 		&delete_driver_settings);
 
-	if (packages == NULL || packages[0] == '\0') {
-		FATAL("need package folder ('packages' parameter)!\n");
+	if (packages != NULL && packages[0] == '\0') {
+		FATAL("invalid package folder ('packages' parameter)!\n");
 		RETURN_ERROR(B_BAD_VALUE);
 	}
 
@@ -628,11 +628,22 @@ Volume::Mount(const char* parameterString)
 		RETURN_ERROR(error);
 	}
 
+	// get our mount point
+	error = vfs_get_mount_point(fFSVolume->id, &fMountPoint.deviceID,
+		&fMountPoint.nodeID);
+	if (error != B_OK)
+		RETURN_ERROR(error);
+
+	// create initial package domain
+	PackageDomain* packageDomain = new(std::nothrow) PackageDomain(this);
+	if (packageDomain == NULL)
+		RETURN_ERROR(B_NO_MEMORY);
+	BReference<PackageDomain> packageDomainReference(packageDomain, true);
+
 	struct stat st;
-	if (stat(packages, &st) < 0) {
-		FATAL("failed to stat: \"%s\": %s\n", packages, strerror(errno));
-		RETURN_ERROR(B_ERROR);
-	}
+	error = packageDomain->Init(packages, &st);
+	if (error != B_OK)
+		RETURN_ERROR(error);
 
 	// If no volume name is given, infer it from the mount type.
 	if (volumeName == NULL) {
@@ -663,12 +674,6 @@ Volume::Mount(const char* parameterString)
 	fRootDirectory->AcquireReference();
 		// one reference for the table
 
-	// get our mount point
-	error = vfs_get_mount_point(fFSVolume->id, &fMountPoint.deviceID,
-		&fMountPoint.nodeID);
-	if (error != B_OK)
-		RETURN_ERROR(error);
-
 	// register with packagefs root
 	error = ::PackageFSRoot::RegisterVolume(this);
 	if (error != B_OK)
@@ -685,8 +690,8 @@ Volume::Mount(const char* parameterString)
 	if (error != B_OK)
 		RETURN_ERROR(error);
 
-	// create default package domain
-	error = _AddInitialPackageDomain(packages);
+	// add initial package domain
+	error = _AddPackageDomain(packageDomain, false);
 	if (error != B_OK)
 		RETURN_ERROR(error);
 
@@ -823,7 +828,7 @@ Volume::AddPackageDomain(const char* path)
 		RETURN_ERROR(B_NO_MEMORY);
 	BReference<PackageDomain> packageDomainReference(packageDomain, true);
 
-	status_t error = packageDomain->Init(path);
+	status_t error = packageDomain->Init(path, NULL);
 	if (error != B_OK)
 		RETURN_ERROR(error);
 
@@ -928,25 +933,11 @@ Volume::_PushJob(Job* job)
 }
 
 
-status_t
-Volume::_AddInitialPackageDomain(const char* path)
-{
-	PackageDomain* domain = new(std::nothrow) PackageDomain(this);
-	if (domain == NULL)
-		RETURN_ERROR(B_NO_MEMORY);
-	BReference<PackageDomain> domainReference(domain, true);
-
-	status_t error = domain->Init(path);
-	if (error != B_OK)
-		RETURN_ERROR(error);
-
-	return _AddPackageDomain(domain, false);
-}
-
-
 status_t
 Volume::_AddPackageDomain(PackageDomain* domain, bool notify)
 {
+	dprintf("packagefs: Adding package domain \"%s\"\n", domain->Path());
+
 	// create a directory listener
 	DomainDirectoryListener* listener = new(std::nothrow)
 		DomainDirectoryListener(this, domain);
@@ -962,7 +953,13 @@ Volume::_AddPackageDomain(PackageDomain* domain, bool notify)
 	}
 
 	// iterate through the dir and create packages
-	DIR* dir = opendir(domain->Path());
+	int fd = dup(domain->DirectoryFD());
+	if (fd < 0) {
+		ERROR("Failed to dup() package domain FD: %s\n", strerror(errno));
+		RETURN_ERROR(errno);
+	}
+
+	DIR* dir = fdopendir(fd);
 	if (dir == NULL) {
 		ERROR("Failed to open package domain directory \"%s\": %s\n",
 			domain->Path(), strerror(errno));