FAT file system service

This patch implements a service which provides access to files and
directories of a FAT file system via the 'File_system' interface.

Fixes #251.

libports/run/libc_ffat_fs.run

@@ -0,0 +1,133 @@
+#
+# \brief  Test for using the libc_fs plugin with the FFAT file system
+# \author Christian Prochaska
+# \date   2012-07-03
+#
+
+if {[catch { exec which mkfs.vfat } ]} {
+        puts stderr "Error: mkfs.vfat not installed, aborting test"; exit }
+
+if {[have_spec linux]} {
+        puts "Run script does not support this platform"; exit }
+
+#
+# Build
+#
+
+build {
+	core init
+	drivers/pci
+	drivers/atapi
+	drivers/timer
+	drivers/sd_card
+	server/ffat_fs
+	test/libc_fs
+}
+
+create_boot_directory
+
+#
+# Generate config
+#
+
+set config {
+<config>
+	<parent-provides>
+		<service name="ROM"/>
+		<service name="RAM"/>
+		<service name="CAP"/>
+		<service name="IRQ"/>
+		<service name="IO_MEM"/>
+		<service name="IO_PORT"/>
+		<service name="PD"/>
+		<service name="RM"/>
+		<service name="CPU"/>
+		<service name="LOG"/>
+		<service name="SIGNAL"/>
+	</parent-provides>
+	<default-route>
+		<any-service> <parent/> <any-child/> </any-service>
+	</default-route>
+	<start name="timer">
+		<resource name="RAM" quantum="1M"/>
+		<provides> <service name="Timer"/> </provides>
+	</start>
+	<start name="ffat_fs">
+		<resource name="RAM" quantum="4M"/>
+		<provides> <service name="File_system"/> </provides>
+		<config> <policy label="" root="/" writeable="yes" /> </config>
+	</start>
+	<start name="test-libc_fs">
+		<resource name="RAM" quantum="2M"/>
+	</start>
+}
+
+append_if [have_spec pci] config {
+	<start name="pci_drv">
+		<resource name="RAM" quantum="2M"/>
+		<provides> <service name="PCI"/> </provides>
+	</start>
+	<start name="atapi_drv">
+		<resource name="RAM" quantum="1M"/>
+		<provides> <service name="Block"/> </provides>
+		<config ata="yes" />
+	</start>
+}
+
+append_if [expr [have_spec pl180] || [have_spec omap4]] config {
+	<start name="sd_card_drv">
+		<resource name="RAM" quantum="1M" />
+		<provides><service name="Block"/></provides>
+	</start>
+}
+
+append config {
+</config>
+}
+
+install_config $config
+
+#
+# Boot modules
+#
+
+# generic modules
+set boot_modules {
+	core init timer ffat_fs
+	ld.lib.so libc.lib.so libc_log.lib.so libc_fs.lib.so
+	test-libc_fs
+}
+
+append_if [have_spec pci]   boot_modules { pci_drv atapi_drv }
+append_if [have_spec pl180] boot_modules { sd_card_drv }
+append_if [have_spec omap4] boot_modules { sd_card_drv }
+
+build_boot_image $boot_modules
+
+#
+# Execute test case
+#
+
+set disk_image "bin/test.hda"
+set cmd "dd if=/dev/zero of=$disk_image bs=1024 count=65536"
+puts "creating disk image: $cmd"
+catch { exec sh -c $cmd }
+
+set cmd "mkfs.vfat -F32 $disk_image"
+puts "formating disk image with vfat file system: $cmd"
+catch { exec sh -c $cmd }
+
+#
+# Qemu
+#
+append qemu_args " -m 128 -nographic "
+append_if [have_spec   pci] qemu_args " -hda $disk_image -boot order=d "
+append_if [have_spec pl180] qemu_args " -drive file=$disk_image,if=sd,cache=writeback "
+
+run_genode_until {.*child exited with exit value 0.*} 60
+
+exec rm -f $disk_image
+
+puts "\ntest succeeded\n"
+
+# vi: set ft=tcl :

libports/src/lib/libc_fs/plugin.cc

@@ -121,7 +121,7 @@ class Plugin_context : public Libc::Plugin_context,
 		: _type(TYPE_FILE), _node_handle(handle), _seek_offset(~0), in_flight(false) { }
 
 		Plugin_context(File_system::Dir_handle handle)
-		: _type(TYPE_DIR), _node_handle(handle), _seek_offset(~0), in_flight(false) { }
+		: _type(TYPE_DIR), _node_handle(handle), _seek_offset(0), in_flight(false) { }
 
 		Plugin_context(File_system::Symlink_handle handle)
 		: _type(TYPE_SYMLINK), _node_handle(handle), _seek_offset(~0), in_flight(false) { }
@@ -346,6 +346,11 @@ class Plugin : public Libc::Plugin
 			return -1;
 		}
 
+		/*
+		 * *basep does not get initialized by the libc and is therefore
+		 * useless for determining a specific directory index. This
+		 * function uses the plugin-internal seek offset instead.
+		 */
 		ssize_t getdirentries(Libc::File_descriptor *fd, char *buf,
 		                      ::size_t nbytes, ::off_t *basep)
 		{
@@ -356,16 +361,9 @@ class Plugin : public Libc::Plugin
 				return -1;
 			}
 
-			unsigned const curr_offset = *basep;
-			unsigned const curr_index = curr_offset / sizeof(struct dirent);
-
-			seek_off_t const orig_seek_offset = context(fd)->seek_offset();
-			context(fd)->seek_offset(curr_index*sizeof(Directory_entry));
 			Directory_entry entry;
 			size_t num_bytes = read(fd, &entry, sizeof(entry));
 
-			context(fd)->seek_offset(orig_seek_offset);
-
 			/* detect end of directory entries */
 			if (num_bytes == 0)
 				return 0;
@@ -384,7 +382,7 @@ class Plugin : public Libc::Plugin
 			case Directory_entry::TYPE_SYMLINK:   dirent->d_type = DT_LNK;  break;
 			}
 
-			dirent->d_fileno = curr_index + 1;
+			dirent->d_fileno = 1 + (context(fd)->seek_offset() / sizeof(struct dirent));
 			dirent->d_reclen = sizeof(struct dirent);
 
 			Genode::strncpy(dirent->d_name, entry.name, sizeof(dirent->d_name));
@@ -423,8 +421,12 @@ class Plugin : public Libc::Plugin
 
 		int mkdir(const char *path, mode_t mode)
 		{
+			Canonical_path canonical_path(path);
+
 			try {
-				file_system()->dir(path, true);
+				File_system::Dir_handle const handle =
+					file_system()->dir(canonical_path.str, true);
+				file_system()->close(handle);
 				return 0;
 			}
 			catch (File_system::Permission_denied)   { errno = EPERM; }
@@ -470,8 +472,7 @@ class Plugin : public Libc::Plugin
 				if (path.str[i] == '/')
 					last_slash = i;
 
-			char dir_path[256];
-			dir_path[0] = 0;
+			char dir_path[256] = "/";
 			if (last_slash > 0)
 				Genode::strncpy(dir_path, path.str,
 				                Genode::min(sizeof(dir_path), last_slash + 1));

libports/src/server/ffat_fs/directory.h

@@ -0,0 +1,122 @@
+/*
+ * \brief  FFAT file-system directory node
+ * \author Christian Prochaska
+ * \date   2012-07-04
+ */
+
+#ifndef _DIRECTORY_H_
+#define _DIRECTORY_H_
+
+/* ffat includes */
+namespace Ffat { extern "C" {
+#include <ffat/ff.h>
+} }
+
+/* local includes */
+#include <node.h>
+
+
+namespace File_system {
+
+	class Directory : public Node
+	{
+		private:
+
+			Ffat::DIR _ffat_dir;
+			int64_t   _prev_index;
+
+		public:
+
+			Directory(const char *name)
+			: Node(name),
+			  _prev_index(-1) { }
+
+			void ffat_dir(Ffat::DIR ffat_dir) { _ffat_dir = ffat_dir; }
+			Ffat::DIR *ffat_dir() { return &_ffat_dir; }
+
+			size_t read(char *dst, size_t len, seek_off_t seek_offset)
+			{
+				bool verbose = false;
+
+				if (verbose)
+					PDBG("len = %zu, seek_offset = %llu", len, seek_offset);
+
+				if (len < sizeof(Directory_entry)) {
+					PERR("read buffer too small for directory entry");
+					return 0;
+				}
+
+				if (seek_offset % sizeof(Directory_entry)) {
+					PERR("seek offset not alighed to sizeof(Directory_entry)");
+					return 0;
+				}
+
+				Directory_entry *e = (Directory_entry *)(dst);
+
+				using namespace Ffat;
+
+				FILINFO ffat_file_info;
+				ffat_file_info.lfname = e->name;
+				ffat_file_info.lfsize = sizeof(e->name);
+
+				int64_t index = seek_offset / sizeof(Directory_entry);
+
+				if (index != (_prev_index + 1)) {
+					/* rewind and iterate from the beginning */
+					f_readdir(&_ffat_dir, 0);
+					for (int i = 0; i < index; i++)
+						f_readdir(&_ffat_dir, &ffat_file_info);
+				}
+
+				_prev_index = index;
+
+				FRESULT res = f_readdir(&_ffat_dir, &ffat_file_info);
+				switch(res) {
+					case FR_OK:
+						break;
+					case FR_INVALID_OBJECT:
+						PERR("f_readdir() failed with error code FR_INVALID_OBJECT");
+						return 0;
+					case FR_DISK_ERR:
+						PERR("f_readdir() failed with error code FR_DISK_ERR");
+						return 0;
+					case FR_INT_ERR:
+						PERR("f_readdir() failed with error code FR_INT_ERR");
+						return 0;
+					case FR_NOT_READY:
+						PERR("f_readdir() failed with error code FR_NOT_READY");
+						return 0;
+					default:
+						/* not supposed to occur according to the libffat documentation */
+						PERR("f_readdir() returned an unexpected error code");
+						return 0;
+				}
+
+				if (ffat_file_info.fname[0] == 0) { /* no (more) entries */
+					return 0;
+				}
+
+				if (e->name[0] == 0) /* use short file name */
+					strncpy(e->name, ffat_file_info.fname, sizeof(e->name));
+
+				if (verbose)
+					PDBG("found dir entry: %s", e->name);
+
+				if ((ffat_file_info.fattrib & AM_DIR) == AM_DIR)
+					e->type = Directory_entry::TYPE_DIRECTORY;
+				else
+					e->type = Directory_entry::TYPE_FILE;
+
+				return sizeof(Directory_entry);
+			}
+
+			size_t write(char const *src, size_t len, seek_off_t)
+			{
+				/* writing to directory nodes is not supported */
+				return 0;
+			}
+
+	};
+}
+
+#endif /* _DIRECTORY_H_ */

libports/src/server/ffat_fs/file.h

@@ -0,0 +1,169 @@
+/*
+ * \brief  FFAT file-system file node
+ * \author Christian Prochaska
+ * \date   2012-07-04
+ */
+
+#ifndef _FILE_H_
+#define _FILE_H_
+
+/* ffat includes */
+namespace Ffat { extern "C" {
+#include <ffat/ff.h>
+} }
+
+/* local includes */
+#include <node.h>
+
+
+namespace File_system {
+
+	class File : public Node
+	{
+		private:
+
+			Ffat::FIL _ffat_fil;
+
+		public:
+
+			File(const char *name) : Node(name) { }
+
+			void ffat_fil(Ffat::FIL ffat_fil) { _ffat_fil = ffat_fil; }
+			Ffat::FIL *ffat_fil() { return &_ffat_fil; }
+
+			size_t read(char *dst, size_t len, seek_off_t seek_offset)
+			{
+				bool verbose = false;
+
+				using namespace Ffat;
+
+				if (verbose)
+					PDBG("len = %zu, seek_offset = %llu", len, seek_offset);
+
+				UINT result;
+
+				if (seek_offset == (seek_off_t)(~0))
+					seek_offset = _ffat_fil.fsize;
+
+				FRESULT res = f_lseek(&_ffat_fil, seek_offset);
+
+				switch(res) {
+					case FR_OK:
+						break;
+					case FR_INVALID_OBJECT:
+						PERR("f_lseek() failed with error code FR_INVALID_OBJECT");
+						return 0;
+					case FR_DISK_ERR:
+						PERR("f_lseek() failed with error code FR_DISK_ERR");
+						return 0;
+					case FR_INT_ERR:
+						PERR("f_lseek() failed with error code FR_INT_ERR");
+						return 0;
+					case FR_NOT_READY:
+						PERR("f_lseek() failed with error code FR_NOT_READY");
+						return 0;
+					default:
+						/* not supposed to occur according to the libffat documentation */
+						PERR("f_lseek() returned an unexpected error code");
+						return 0;
+				}
+
+				res = f_read(&_ffat_fil, dst, len, &result);
+
+				switch(res) {
+					case FR_OK:
+						if (verbose)
+							PDBG("result = %zu", result);
+						return result;
+					case FR_DENIED:
+						PDBG("f_read() failed with error code FR_DENIED");
+						return 0;
+					case FR_INVALID_OBJECT:
+						PERR("f_read() failed with error code FR_INVALID_OBJECT");
+						return 0;
+					case FR_DISK_ERR:
+						PERR("f_read() failed with error code FR_DISK_ERR");
+						return 0;
+					case FR_INT_ERR:
+						PERR("f_read() failed with error code FR_INT_ERR");
+						return 0;
+					case FR_NOT_READY:
+						PERR("f_read() failed with error code FR_NOT_READY");
+						return 0;
+					default:
+						/* not supposed to occur according to the libffat documentation */
+						PERR("f_read() returned an unexpected error code");
+						return 0;
+				}
+			}
+
+			size_t write(char const *src, size_t len, seek_off_t seek_offset)
+			{
+				bool verbose = false;
+
+				if (verbose)
+					PDBG("len = %zu, seek_offset = %llu", len, seek_offset);
+
+				using namespace Ffat;
+
+				UINT result;
+
+				if (seek_offset == (seek_off_t)(~0))
+					seek_offset = _ffat_fil.fsize;
+
+				FRESULT res = f_lseek(&_ffat_fil, seek_offset);
+
+				switch(res) {
+					case FR_OK:
+						break;
+					case FR_INVALID_OBJECT:
+						PERR("f_lseek() failed with error code FR_INVALID_OBJECT");
+						return 0;
+					case FR_DISK_ERR:
+						PERR("f_lseek() failed with error code FR_DISK_ERR");
+						return 0;
+					case FR_INT_ERR:
+						PERR("f_lseek() failed with error code FR_INT_ERR");
+						return 0;
+					case FR_NOT_READY:
+						PERR("f_lseek() failed with error code FR_NOT_READY");
+						return 0;
+					default:
+						/* not supposed to occur according to the libffat documentation */
+						PERR("f_lseek() returned an unexpected error code");
+						return 0;
+				}
+
+				res = f_write(&_ffat_fil, src, len, &result);
+
+				switch(res) {
+					case FR_OK:
+						if (verbose)
+							PDBG("result = %zu", result);
+						return result;
+					case FR_DENIED:
+						PERR("f_write() failed with error code FR_DENIED");
+						return 0;
+					case FR_INVALID_OBJECT:
+						PERR("f_write() failed with error code FR_INVALID_OBJECT");
+						return 0;
+					case FR_DISK_ERR:
+						PERR("f_write() failed with error code FR_DISK_ERR");
+						return 0;
+					case FR_INT_ERR:
+						PERR("f_write() failed with error code FR_INT_ERR");
+						return 0;
+					case FR_NOT_READY:
+						PERR("f_write() failed with error code FR_NOT_READY");
+						return 0;
+					default:
+						/* not supposed to occur according to the libffat documentation */
+						PERR("f_write() returned an unexpected error code");
+						return 0;
+				}
+			}
+
+	};
+}
+
+#endif /* _FILE_H_ */

libports/src/server/ffat_fs/node.h

@@ -0,0 +1,58 @@
+/*
+ * \brief  FFAT file-system node
+ * \author Christian Prochaska
+ * \date   2012-07-04
+ */
+
+#ifndef _NODE_H_
+#define _NODE_H_
+
+/* ffat includes */
+namespace Ffat { extern "C" {
+#include <ffat/ff.h>
+} }
+
+namespace File_system {
+
+	class Node
+	{
+		protected:
+
+			char _name[_MAX_LFN + 1];
+
+		public:
+
+			Node(const char *name)
+			{
+				strncpy(_name, name, sizeof(_name));
+
+				/* remove any trailing slashes, except for "/" */
+				size_t index = strlen(_name) - 1;
+				while ((index > 0) && (_name[index] == '/'))
+					_name[index--] = 0;
+			}
+
+			char const *name() const { return _name; }
+
+			/*
+			 * A generic Node object can be created to represent a file or
+			 * directory by its name without opening it, so the functions
+			 * of this class must not be abstract.
+			 */
+
+			virtual size_t read(char *dst, size_t len, seek_off_t)
+			{
+				PERR("read() called on generic Node object");
+				return 0;
+			}
+
+			virtual size_t write(char const *src, size_t len, seek_off_t)
+			{
+				PERR("write() called on generic Node object");
+				return 0;
+			}
+	};
+
+}
+
+#endif /* _NODE_H_ */

libports/src/server/ffat_fs/node_handle_registry.h

@@ -0,0 +1,130 @@
+/*
+ * \brief  Facility for managing the session-local node-handle namespace
+ * \author Norman Feske
+ * \date   2012-04-11
+ */
+
+#ifndef _NODE_HANDLE_REGISTRY_H_
+#define _NODE_HANDLE_REGISTRY_H_
+
+namespace File_system {
+
+	class Node;
+	class Directory;
+	class File;
+	class Symlink;
+
+	/**
+	 * Type trait for determining the node type for a given handle type
+	 */
+	template<typename T> struct Node_type;
+	template<> struct Node_type<Node_handle>    { typedef Node      Type; };
+	template<> struct Node_type<Dir_handle>     { typedef Directory Type; };
+	template<> struct Node_type<File_handle>    { typedef File      Type; };
+	template<> struct Node_type<Symlink_handle> { typedef Symlink   Type; };
+
+
+	/**
+	 * Type trait for determining the handle type for a given node type
+	 */
+	template<typename T> struct Handle_type;
+	template<> struct Handle_type<Node>      { typedef Node_handle    Type; };
+	template<> struct Handle_type<Directory> { typedef Dir_handle     Type; };
+	template<> struct Handle_type<File>      { typedef File_handle    Type; };
+	template<> struct Handle_type<Symlink>   { typedef Symlink_handle Type; };
+
+
+	class Node_handle_registry
+	{
+		private:
+
+			/* maximum number of open nodes per session */
+			enum { MAX_NODE_HANDLES = 128U };
+
+			Lock mutable _lock;
+
+			Node *_nodes[MAX_NODE_HANDLES];
+
+			/**
+			 * Allocate node handle
+			 *
+			 * \throw Out_of_node_handles
+			 */
+			int _alloc(Node *node)
+			{
+				Lock::Guard guard(_lock);
+
+				for (unsigned i = 0; i < MAX_NODE_HANDLES; i++)
+					if (!_nodes[i]) {
+						_nodes[i] = node;
+						return i;
+					}
+
+				throw Out_of_node_handles();
+			}
+
+			bool _in_range(int handle) const
+			{
+				return ((handle >= 0) && (handle < MAX_NODE_HANDLES));
+			}
+
+		public:
+
+			Node_handle_registry()
+			{
+				for (unsigned i = 0; i < MAX_NODE_HANDLES; i++)
+					_nodes[i] = 0;
+			}
+
+			template <typename NODE_TYPE>
+			typename Handle_type<NODE_TYPE>::Type alloc(NODE_TYPE *node)
+			{
+				typedef typename Handle_type<NODE_TYPE>::Type Handle;
+				return Handle(_alloc(node));
+			}
+
+			/**
+			 * Release node handle
+			 */
+			void free(Node_handle handle)
+			{
+				Lock::Guard guard(_lock);
+
+				if (_in_range(handle.value))
+					_nodes[handle.value] = 0;
+			}
+
+			/**
+			 * Lookup node using its handle as key
+			 *
+			 * \throw Invalid_handle
+			 */
+			template <typename HANDLE_TYPE>
+			typename Node_type<HANDLE_TYPE>::Type *lookup(HANDLE_TYPE handle)
+			{
+				Lock::Guard guard(_lock);
+
+				if (!_in_range(handle.value))
+					throw Invalid_handle();
+
+				typedef typename Node_type<HANDLE_TYPE>::Type Node;
+				Node *node = dynamic_cast<Node *>(_nodes[handle.value]);
+				if (!node)
+					throw Invalid_handle();
+
+				return node;
+			}
+
+			bool refer_to_same_node(Node_handle h1, Node_handle h2) const
+			{
+				Lock::Guard guard(_lock);
+
+				if (!_in_range(h1.value) || !_in_range(h2.value))
+					throw Invalid_handle();
+
+				return _nodes[h1.value] == _nodes[h2.value];
+			}
+	};
+}
+
+#endif /* _NODE_HANDLE_REGISTRY_H_ */

libports/src/server/ffat_fs/target.mk

@@ -0,0 +1,4 @@
+TARGET   = ffat_fs
+SRC_CC   = main.cc
+LIBS     = cxx env server signal ffat_block
+INC_DIR += $(PRG_DIR)

libports/src/server/ffat_fs/util.h

@@ -0,0 +1,126 @@
+/*
+ * \brief  Utilities
+ * \author Norman Feske
+ * \author Christian Prochaska
+ * \date   2012-04-11
+ */
+
+#ifndef _UTIL_H_
+#define _UTIL_H_
+
+/* Genode includes */
+#include <util/string.h>
+
+
+/**
+ * Return base-name portion of null-terminated path string
+ */
+static inline char const *basename(char const *path)
+{
+	char const *start = path;
+
+	for (; *path; path++)
+		if (*path == '/')
+			start = path + 1;
+
+	return start;
+}
+
+
+/**
+ * Return true if specified path is a base name (contains no path delimiters)
+ */
+static inline bool is_basename(char const *path)
+{
+	for (; *path; path++)
+		if (*path == '/')
+			return false;
+
+	return true;
+}
+
+
+/**
+ * Return true if character 'c' occurs in null-terminated string 'str'
+ */
+static inline bool string_contains(char const *str, char c)
+{
+	for (; *str; str++)
+		if (*str == c)
+			return true;
+	return false;
+}
+
+
+/**
+ * Return true if null-terminated string 'substr' occurs in null-terminated
+ * string 'str'
+ */
+static bool string_contains(char const *str, char const *substr)
+{
+	using namespace Genode;
+
+	size_t str_len = strlen(str);
+	size_t substr_len = strlen(substr);
+
+	if (str_len < substr_len)
+		return false;
+
+	for (size_t i = 0; i <= (str_len - substr_len); i++)
+		if (strcmp(&str[i], substr, substr_len) == 0)
+			return true;
+
+	return false;
+}
+
+
+/**
+ * Return true if 'str' is a valid file name
+ */
+static inline bool valid_filename(char const *str)
+{
+	if (!str) return false;
+
+	/* must have at least one character */
+	if (str[0] == 0) return false;
+
+	/* must not contain '/' or '\' or ':' */
+	if (string_contains(str, '/') ||
+	    string_contains(str, '\\') ||
+	    string_contains(str, ':'))
+		return false;
+
+	return true;
+}
+
+/**
+ * Return true if 'str' is a valid path
+ */
+static inline bool valid_path(char const *str)
+{
+	if (!str) return false;
+
+	/* must start with '/' */
+	if (str[0] != '/')
+		return false;
+
+	/* must not contain '\' or ':' */
+	if (string_contains(str, '\\') ||
+	    string_contains(str, ':'))
+		return false;
+
+	/* must not contain "/../" */
+	 if (string_contains(str, "/../")) return false;
+
+	return true;
+}
+
+/**
+ * Return true if 'str' is "/"
+ */
+static inline bool is_root(const char *str)
+{
+	return (Genode::strcmp(str, "/") == 0);
+}
+
+#endif /* _UTIL_H_ */

os/include/file_system_session/file_system_session.h

@@ -128,7 +128,7 @@ namespace File_system {
 	 */
 	enum Mode { STAT_ONLY = 0, READ_ONLY = 1, WRITE_ONLY = 2, READ_WRITE = 3 };
 
-	enum { MAX_NAME_LEN = 128, MAX_PATH_LEN = 1024 };
+	enum { MAX_NAME_LEN = 256, MAX_PATH_LEN = 1024 };
 
 	typedef Rpc_in_buffer<MAX_NAME_LEN> Name;
 	typedef Rpc_in_buffer<MAX_PATH_LEN> Path;