base-linux: hybrid file-system server
The current implementation is missing support for symbolic links. Fixes #944.
This commit is contained in:
Christian Helmuth
Norman Feske
parent
1bbd54c9b7
commit
eda44d6154
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@ -0,0 +1,79 @@
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#
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# \brief Test for using the libc_fs plugin with the Linux file system
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# \author Norman Feske
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# \author Christian Helmuth
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# \date 2013-11-07
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#
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assert_spec linux
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#
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# Build
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#
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build { core init server/lx_fs test/libc_fs }
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create_boot_directory
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#
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# Generate config
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#
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install_config {
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<config>
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<parent-provides>
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<service name="ROM"/>
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<service name="RAM"/>
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<service name="CAP"/>
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<service name="PD"/>
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<service name="RM"/>
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<service name="CPU"/>
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<service name="LOG"/>
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<service name="SIGNAL"/>
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</parent-provides>
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<default-route>
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<any-service> <parent/> <any-child/> </any-service>
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</default-route>
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<start name="lx_fs">
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<resource name="RAM" quantum="4M"/>
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<provides> <service name="File_system"/> </provides>
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<config> <policy label="" root="/libc_fs" writeable="yes" /> </config>
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</start>
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<start name="test-libc_fs">
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<resource name="RAM" quantum="2M"/>
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</start>
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</config>
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}
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#
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# Create test-directory structure
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#
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exec mkdir -p bin/libc_fs
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#
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# Boot modules
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#
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build_boot_image {
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core init
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ld.lib.so libc.lib.so libc_log.lib.so libc_fs.lib.so
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lx_fs test-libc_fs
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libc_fs
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}
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#
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# Execute test case
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#
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run_genode_until {.*child exited with exit value 0.*} 60
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puts "\ntest succeeded\n"
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#
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# Cleanup test-directory structure
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#
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exec rm -r bin/libc_fs
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# vi: set ft=tcl :
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@ -0,0 +1,44 @@
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This directory contains an Genode file-system service to Linux host fs
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wrapper.
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Configuration
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~~~~~~~~~~~~~
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Access to the file system can be tailored for each session depending on the
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session's label. By default, no permissions are granted to any session.
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To selectively permit access to (a part of) the file system, at least one
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policy must be defined.
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The following configuration illustates the way of how to express policy.
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! <config>
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! <!-- constrain sessions according to their labels -->
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! <policy label="noux -> root" root="/" />
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! <policy label="noux -> home" root="/home/user" writeable="yes" />
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! <policy label="noux -> tmp" root="/tmp" writeable="yes" />
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! </config>
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Session-specific access-control policy is expressed via one or more '<policy>'
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nodes. At session-creation time, each policy node is matched against the label
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of the new session. If the label of a policy node matches, the defined policy
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is applied. If multiple policies match, the one with the longest 'label'
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attribute (the most specific one) is selected.
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A policy node may contain the following attributes. The mandatory 'root'
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attribute defines the viewport of the session onto the file system. The
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optional 'writeable' attribute grants the permission to modify the file system.
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Example
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~~~~~~~
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To illustrate the use of lx_fs, refer to the 'base-linux/run/lx_fs.run'
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script.
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Notes
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~~~~~
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If the Linux file system experiences changes from other processes
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'inotify' may help to keep the servers cache up-to-date. This is not
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implemented yet.
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/*
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* \brief File-system directory node
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* \author Norman Feske
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* \author Christian Helmuth
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* \date 2013-11-11
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*/
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#ifndef _DIRECTORY_H_
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#define _DIRECTORY_H_
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/* Genode include */
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#include <os/path.h>
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/* local includes */
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#include <node.h>
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#include <util.h>
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#include <file.h>
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#include <lx_util.h>
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namespace File_system {
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class Directory;
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}
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class File_system::Directory : public Node
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{
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private:
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typedef Genode::Path<MAX_PATH_LEN> Path;
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DIR *_fd;
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Path _path;
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Allocator &_alloc;
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unsigned long _inode(char const *path, bool create)
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{
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int ret;
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if (create) {
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mode_t ugo = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
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ret = mkdir(path, ugo);
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if (ret == -1)
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throw No_space();
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}
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struct stat s;
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ret = lstat(path, &s);
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if (ret == -1)
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throw Lookup_failed();
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return s.st_ino;
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}
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DIR *_open(char const *path)
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{
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DIR *fd = opendir(path);
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if (!fd)
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throw Lookup_failed();
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return fd;
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}
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public:
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Directory(Allocator &alloc, char const *path, bool create)
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:
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Node(_inode(path, create)),
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_fd(_open(path)),
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_path(path, "./"),
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_alloc(alloc)
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{
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Node::name(basename(path));
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}
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virtual ~Directory()
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{
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closedir(_fd);
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}
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/* FIXME returned file node must be locked */
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File * file(char const *name, Mode mode, bool create)
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{
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File *file = new (&_alloc) File(dirfd(_fd), name, mode, create);
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file->lock();
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return file;
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}
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/* FIXME returned directory node must be locked */
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Directory * subdir(char const *path, bool create)
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{
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Path dir_path(path, _path.base());
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Directory *dir = new (&_alloc) Directory(_alloc, dir_path.base(), create);
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dir->lock();
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return dir;
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}
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Node * node(char const *path)
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{
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Path node_path(path, _path.base());
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/*
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* XXX Currently, symlinks are transparently dereferenced by the
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* use of stat(). For symlink detection we would need lstat()
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* and implement special handling of the root, which may be a
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* link!
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*/
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struct stat s;
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int ret = stat(node_path.base(), &s);
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if (ret == -1)
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throw Lookup_failed();
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Node *node = 0;
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if (S_ISDIR(s.st_mode))
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node = new (&_alloc) Directory(_alloc, node_path.base(), false);
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else if (S_ISREG(s.st_mode))
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node = new (&_alloc) File(node_path.base(), STAT_ONLY);
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else
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throw Lookup_failed();
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node->lock();
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return node;
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}
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size_t read(char *dst, size_t len, seek_off_t seek_offset)
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{
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if (len < sizeof(Directory_entry)) {
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PERR("read buffer too small for directory entry");
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return 0;
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}
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if (seek_offset % sizeof(Directory_entry)) {
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PERR("seek offset not aligned to sizeof(Directory_entry)");
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return 0;
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}
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seek_off_t index = seek_offset / sizeof(Directory_entry);
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/* seek to index and read entry */
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struct dirent *dent;
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rewinddir(_fd);
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for (unsigned i = 0; i <= index; ++i) {
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dent = readdir(_fd);
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}
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if (!dent)
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return 0;
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Directory_entry *e = (Directory_entry *)(dst);
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switch (dent->d_type) {
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case DT_REG: e->type = Directory_entry::TYPE_FILE; break;
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case DT_DIR: e->type = Directory_entry::TYPE_DIRECTORY; break;
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case DT_LNK: e->type = Directory_entry::TYPE_SYMLINK; break;
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default:
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return 0;
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}
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strncpy(e->name, dent->d_name, sizeof(e->name));
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return sizeof(Directory_entry);
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}
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size_t write(char const *src, size_t len, seek_off_t seek_offset)
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{
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/* writing to directory nodes is not supported */
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return 0;
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}
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size_t num_entries() const
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{
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unsigned num = 0;
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rewinddir(_fd);
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while (readdir(_fd)) ++num;
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return num;
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}
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};
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#endif /* _DIRECTORY_H_ */
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/*
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* \brief File node
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* \author Norman Feske
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* \author Christian Helmuth
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* \date 2013-11-11
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*/
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#ifndef _FILE_H_
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#define _FILE_H_
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/* local includes */
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#include <node.h>
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#include <lx_util.h>
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namespace File_system {
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class File;
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}
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class File_system::File : public Node
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{
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private:
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int _fd;
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unsigned long _inode(int dir, char const *name, bool create)
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{
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int ret;
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if (create) {
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mode_t ugo = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
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ret = mknodat(dir, name, S_IFREG | ugo, 0);
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if (ret == -1 && errno != EEXIST)
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throw No_space();
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}
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struct stat s;
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ret = fstatat(dir, name, &s, 0);
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if (ret == -1)
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throw Lookup_failed();
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return s.st_ino;
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}
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unsigned long _inode_path(char const *path)
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{
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int ret;
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struct stat s;
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ret = stat(path, &s);
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if (ret == -1)
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throw Lookup_failed();
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return s.st_ino;
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}
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int _open(int dir, char const *name, Mode mode)
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{
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int fd = openat(dir, name, access_mode(mode));
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if (fd == -1)
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throw Lookup_failed();
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return fd;
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}
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int _open_path(char const *path, Mode mode)
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{
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int fd = open(path, access_mode(mode));
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if (fd == -1)
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throw Lookup_failed();
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return fd;
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}
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public:
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File(int dir,
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char const *name,
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Mode mode,
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bool create)
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:
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Node(_inode(dir, name, create)),
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_fd(_open(dir, name, mode))
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{
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Node::name(name);
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}
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File(char const *path, Mode mode)
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:
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Node(_inode_path(path)),
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_fd(_open_path(path, mode))
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{
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Node::name(basename(path));
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}
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size_t read(char *dst, size_t len, seek_off_t seek_offset)
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{
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int ret = pread(_fd, dst, len, seek_offset);
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return ret == -1 ? 0 : ret;
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}
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size_t write(char const *src, size_t len, seek_off_t seek_offset)
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{
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/* should we append? */
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if (seek_offset == ~0ULL) {
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off_t off = lseek(_fd, 0, SEEK_END);
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if (off == -1)
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return 0;
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seek_offset = off;
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}
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int ret = pwrite(_fd, src, len, seek_offset);
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return ret == -1 ? 0 : ret;
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}
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file_size_t length() const
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{
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struct stat s;
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if (fstat(_fd, &s) < 0)
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return 0;
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return s.st_size;
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}
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void truncate(file_size_t size)
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{
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ftruncate(_fd, size);
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mark_as_updated();
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}
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};
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#endif /* _FILE_H_ */
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@ -0,0 +1,38 @@
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/*
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* \brief Linux utilities
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* \author Christian Helmuth
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* \date 2013-11-11
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*/
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#ifndef _LX_UTIL_H_
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#define _LX_UTIL_H_
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/* Genode includes */
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#include <file_system_session/file_system_session.h>
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/* Linux includes */
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#include <errno.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <dirent.h>
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#include <sys/stat.h>
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namespace File_system {
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int access_mode(File_system::Mode const &mode);
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}
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int File_system::access_mode(File_system::Mode const &mode)
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{
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switch (mode) {
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case STAT_ONLY:
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case READ_ONLY: return O_RDONLY;
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case WRITE_ONLY: return O_WRONLY;
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case READ_WRITE: return O_RDWR;
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}
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return O_RDONLY;
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}
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#endif
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@ -0,0 +1,437 @@
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/*
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* \brief RAM file system
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* \author Norman Feske
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* \date 2012-04-11
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*/
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/*
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* Copyright (C) 2012-2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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/* Genode includes */
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#include <file_system_session/rpc_object.h>
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#include <root/component.h>
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#include <os/attached_rom_dataspace.h>
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#include <os/config.h>
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#include <os/server.h>
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#include <os/session_policy.h>
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#include <util/xml_node.h>
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/* local includes */
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#include <directory.h>
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#include <node_handle_registry.h>
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namespace File_system {
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struct Main;
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struct Session_component;
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struct Root;
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}
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class File_system::Session_component : public Session_rpc_object
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{
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private:
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Server::Entrypoint &_ep;
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Allocator &_md_alloc;
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Directory &_root;
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Node_handle_registry _handle_registry;
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bool _writable;
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Signal_rpc_member<Session_component> _process_packet_dispatcher;
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/******************************
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** Packet-stream processing **
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******************************/
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/**
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* Perform packet operation
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*
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* \return true on success, false on failure
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*/
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void _process_packet_op(Packet_descriptor &packet, Node &node)
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{
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void * const content = tx_sink()->packet_content(packet);
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size_t const length = packet.length();
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seek_off_t const offset = packet.position();
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if (!content || (packet.length() > packet.size())) {
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packet.succeeded(false);
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return;
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}
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/* resulting length */
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size_t res_length = 0;
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switch (packet.operation()) {
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case Packet_descriptor::READ:
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res_length = node.read((char *)content, length, offset);
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break;
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case Packet_descriptor::WRITE:
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res_length = node.write((char const *)content, length, offset);
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break;
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}
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packet.length(res_length);
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packet.succeeded(res_length > 0);
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||||
}
|
||||
|
||||
void _process_packet()
|
||||
{
|
||||
Packet_descriptor packet = tx_sink()->get_packet();
|
||||
|
||||
/* assume failure by default */
|
||||
packet.succeeded(false);
|
||||
|
||||
try {
|
||||
Node *node = _handle_registry.lookup_and_lock(packet.handle());
|
||||
Node_lock_guard guard(*node);
|
||||
|
||||
_process_packet_op(packet, *node);
|
||||
}
|
||||
catch (Invalid_handle) { PERR("Invalid_handle"); }
|
||||
catch (Size_limit_reached) { PERR("Size_limit_reached"); }
|
||||
|
||||
/*
|
||||
* The 'acknowledge_packet' function cannot block because we
|
||||
* checked for 'ready_to_ack' in '_process_packets'.
|
||||
*/
|
||||
tx_sink()->acknowledge_packet(packet);
|
||||
}
|
||||
|
||||
/**
|
||||
* Called by signal dispatcher, executed in the context of the main
|
||||
* thread (not serialized with the RPC functions)
|
||||
*/
|
||||
void _process_packets(unsigned)
|
||||
{
|
||||
while (tx_sink()->packet_avail()) {
|
||||
|
||||
/*
|
||||
* Make sure that the '_process_packet' function does not
|
||||
* block.
|
||||
*
|
||||
* If the acknowledgement queue is full, we defer packet
|
||||
* processing until the client processed pending
|
||||
* acknowledgements and thereby emitted a ready-to-ack
|
||||
* signal. Otherwise, the call of 'acknowledge_packet()'
|
||||
* in '_process_packet' would infinitely block the context
|
||||
* of the main thread. The main thread is however needed
|
||||
* for receiving any subsequent 'ready-to-ack' signals.
|
||||
*/
|
||||
if (!tx_sink()->ready_to_ack())
|
||||
return;
|
||||
|
||||
_process_packet();
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Check if string represents a valid path (must start with '/')
|
||||
*/
|
||||
static void _assert_valid_path(char const *path)
|
||||
{
|
||||
if (!path || path[0] != '/') {
|
||||
PWRN("malformed path '%s'", path);
|
||||
throw Lookup_failed();
|
||||
}
|
||||
}
|
||||
|
||||
public:
|
||||
|
||||
/**
|
||||
* Constructor
|
||||
*/
|
||||
Session_component(size_t tx_buf_size,
|
||||
Server::Entrypoint &ep,
|
||||
char const *root_dir,
|
||||
bool writable,
|
||||
Allocator &md_alloc)
|
||||
:
|
||||
Session_rpc_object(env()->ram_session()->alloc(tx_buf_size), ep.rpc_ep()),
|
||||
_ep(ep),
|
||||
_md_alloc(md_alloc),
|
||||
_root(*new (&_md_alloc) Directory(_md_alloc, root_dir, false)),
|
||||
_writable(writable),
|
||||
_process_packet_dispatcher(*this, &Session_component::_process_packets)
|
||||
{
|
||||
/*
|
||||
* Register '_process_packets' dispatch function as signal
|
||||
* handler for packet-avail and ready-to-ack signals.
|
||||
*/
|
||||
Signal_context_capability sigh(_ep.manage(_process_packet_dispatcher));
|
||||
|
||||
_tx.sigh_packet_avail(sigh);
|
||||
_tx.sigh_ready_to_ack(sigh);
|
||||
}
|
||||
|
||||
/**
|
||||
* Destructor
|
||||
*/
|
||||
~Session_component()
|
||||
{
|
||||
_ep.dissolve(_process_packet_dispatcher);
|
||||
Dataspace_capability ds = tx_sink()->dataspace();
|
||||
env()->ram_session()->free(static_cap_cast<Ram_dataspace>(ds));
|
||||
destroy(&_md_alloc, &_root);
|
||||
}
|
||||
|
||||
|
||||
/***************************
|
||||
** File_system interface **
|
||||
***************************/
|
||||
|
||||
File_handle file(Dir_handle dir_handle, Name const &name, Mode mode, bool create)
|
||||
{
|
||||
if (!valid_name(name.string()))
|
||||
throw Invalid_name();
|
||||
|
||||
Directory *dir = _handle_registry.lookup_and_lock(dir_handle);
|
||||
Node_lock_guard dir_guard(*dir);
|
||||
|
||||
if (!_writable)
|
||||
if (create || (mode != STAT_ONLY && mode != READ_ONLY))
|
||||
throw Permission_denied();
|
||||
|
||||
File *file = dir->file(name.string(), mode, create);
|
||||
|
||||
Node_lock_guard file_guard(*file);
|
||||
return _handle_registry.alloc(file);
|
||||
}
|
||||
|
||||
Symlink_handle symlink(Dir_handle dir_handle, Name const &name, bool create)
|
||||
{
|
||||
PERR("%s not implemented", __func__);
|
||||
return Symlink_handle();
|
||||
}
|
||||
|
||||
Dir_handle dir(Path const &path, bool create)
|
||||
{
|
||||
char const *path_str = path.string();
|
||||
|
||||
_assert_valid_path(path_str);
|
||||
|
||||
/* skip leading '/' */
|
||||
path_str++;
|
||||
|
||||
if (!_writable && create)
|
||||
throw Permission_denied();
|
||||
|
||||
if (!path.is_valid_string())
|
||||
throw Name_too_long();
|
||||
|
||||
Directory *dir = _root.subdir(path_str, create);
|
||||
Node_lock_guard guard(*dir);
|
||||
return _handle_registry.alloc(dir);
|
||||
}
|
||||
|
||||
Node_handle node(Path const &path)
|
||||
{
|
||||
char const *path_str = path.string();
|
||||
|
||||
_assert_valid_path(path_str);
|
||||
|
||||
Node *node = _root.node(path_str + 1);
|
||||
|
||||
Node_lock_guard guard(*node);
|
||||
return _handle_registry.alloc(node);
|
||||
}
|
||||
|
||||
void close(Node_handle handle)
|
||||
{
|
||||
/* FIXME when to destruct node? */
|
||||
_handle_registry.free(handle);
|
||||
}
|
||||
|
||||
Status status(Node_handle node_handle)
|
||||
{
|
||||
Node *node = _handle_registry.lookup_and_lock(node_handle);
|
||||
Node_lock_guard guard(*node);
|
||||
|
||||
Status s;
|
||||
s.inode = node->inode();
|
||||
s.size = 0;
|
||||
s.mode = 0;
|
||||
|
||||
File *file = dynamic_cast<File *>(node);
|
||||
if (file) {
|
||||
s.size = file->length();
|
||||
s.mode = File_system::Status::MODE_FILE;
|
||||
return s;
|
||||
}
|
||||
|
||||
Directory *dir = dynamic_cast<Directory *>(node);
|
||||
if (dir) {
|
||||
s.size = dir->num_entries()*sizeof(Directory_entry);
|
||||
s.mode = File_system::Status::MODE_DIRECTORY;
|
||||
return s;
|
||||
}
|
||||
|
||||
PERR("%s for symlinks not implemented", __func__);
|
||||
|
||||
return Status();
|
||||
}
|
||||
|
||||
void control(Node_handle, Control)
|
||||
{
|
||||
PERR("%s not implemented", __func__);
|
||||
}
|
||||
|
||||
void unlink(Dir_handle, Name const &)
|
||||
{
|
||||
PERR("%s not implemented", __func__);
|
||||
}
|
||||
|
||||
void truncate(File_handle file_handle, file_size_t size)
|
||||
{
|
||||
if (!_writable)
|
||||
throw Permission_denied();
|
||||
|
||||
File *file = _handle_registry.lookup_and_lock(file_handle);
|
||||
Node_lock_guard file_guard(*file);
|
||||
file->truncate(size);
|
||||
}
|
||||
|
||||
void move(Dir_handle, Name const &, Dir_handle, Name const &)
|
||||
{
|
||||
PERR("%s not implemented", __func__);
|
||||
}
|
||||
|
||||
void sigh(Node_handle node_handle, Signal_context_capability sigh)
|
||||
{
|
||||
_handle_registry.sigh(node_handle, sigh);
|
||||
}
|
||||
};
|
||||
|
||||
|
||||
class File_system::Root : public Root_component<Session_component>
|
||||
{
|
||||
private:
|
||||
|
||||
Server::Entrypoint &_ep;
|
||||
|
||||
protected:
|
||||
|
||||
Session_component *_create_session(const char *args)
|
||||
{
|
||||
/*
|
||||
* Determine client-specific policy defined implicitly by
|
||||
* the client's label.
|
||||
*/
|
||||
|
||||
char const *root_dir = ".";
|
||||
bool writeable = false;
|
||||
|
||||
enum { ROOT_MAX_LEN = 256 };
|
||||
char root[ROOT_MAX_LEN];
|
||||
root[0] = 0;
|
||||
|
||||
try {
|
||||
Session_label label(args);
|
||||
Session_policy policy(label);
|
||||
|
||||
/*
|
||||
* Determine directory that is used as root directory of
|
||||
* the session.
|
||||
*/
|
||||
try {
|
||||
policy.attribute("root").value(root, sizeof(root));
|
||||
|
||||
/*
|
||||
* Make sure the root path is specified with a
|
||||
* leading path delimiter. For performing the
|
||||
* lookup, we skip the first character.
|
||||
*/
|
||||
if (root[0] != '/')
|
||||
throw Lookup_failed();
|
||||
|
||||
root_dir = root + 1;
|
||||
} catch (Xml_node::Nonexistent_attribute) {
|
||||
PERR("Missing \"root\" attribute in policy definition");
|
||||
throw Root::Unavailable();
|
||||
} catch (Lookup_failed) {
|
||||
PERR("Session root directory \"%s\" does not exist", root);
|
||||
throw Root::Unavailable();
|
||||
}
|
||||
|
||||
/*
|
||||
* Determine if write access is permitted for the session.
|
||||
*/
|
||||
try {
|
||||
writeable = policy.attribute("writeable").has_value("yes");
|
||||
} catch (Xml_node::Nonexistent_attribute) { }
|
||||
|
||||
} catch (Session_policy::No_policy_defined) {
|
||||
PERR("Invalid session request, no matching policy");
|
||||
throw Root::Unavailable();
|
||||
}
|
||||
|
||||
size_t ram_quota =
|
||||
Arg_string::find_arg(args, "ram_quota" ).ulong_value(0);
|
||||
size_t tx_buf_size =
|
||||
Arg_string::find_arg(args, "tx_buf_size").ulong_value(0);
|
||||
|
||||
/*
|
||||
* Check if donated ram quota suffices for session data,
|
||||
* and communication buffer.
|
||||
*/
|
||||
size_t session_size = sizeof(Session_component) + tx_buf_size;
|
||||
if (max((size_t)4096, session_size) > ram_quota) {
|
||||
PERR("insufficient 'ram_quota', got %zd, need %zd",
|
||||
ram_quota, session_size);
|
||||
throw Root::Quota_exceeded();
|
||||
}
|
||||
return new (md_alloc())
|
||||
Session_component(tx_buf_size, _ep, root_dir, writeable, *md_alloc());
|
||||
}
|
||||
|
||||
public:
|
||||
|
||||
/**
|
||||
* Constructor
|
||||
*
|
||||
* \param ep entrypoint
|
||||
* \param sig_rec signal receiver used for handling the
|
||||
* data-flow signals of packet streams
|
||||
* \param md_alloc meta-data allocator
|
||||
*/
|
||||
Root(Server::Entrypoint &ep, Allocator &md_alloc)
|
||||
:
|
||||
Root_component<Session_component>(&ep.rpc_ep(), &md_alloc),
|
||||
_ep(ep)
|
||||
{ }
|
||||
};
|
||||
|
||||
|
||||
struct File_system::Main
|
||||
{
|
||||
Server::Entrypoint &ep;
|
||||
|
||||
/*
|
||||
* Initialize root interface
|
||||
*/
|
||||
Sliced_heap sliced_heap = { env()->ram_session(), env()->rm_session() };
|
||||
|
||||
Root fs_root = { ep, sliced_heap };
|
||||
|
||||
Main(Server::Entrypoint &ep) : ep(ep)
|
||||
{
|
||||
env()->parent()->announce(ep.manage(fs_root));
|
||||
}
|
||||
};
|
||||
|
||||
|
||||
/**********************
|
||||
** Server framework **
|
||||
**********************/
|
||||
|
||||
char const * Server::name() { return "lx_fs_ep"; }
|
||||
Genode::size_t Server::stack_size() { return 2048 * sizeof(long); }
|
||||
void Server::construct(Server::Entrypoint &ep) { static File_system::Main inst(ep); }
|
||||
|
|
@ -0,0 +1,134 @@
|
|||
/*
|
||||
* \brief File-system node
|
||||
* \author Norman Feske
|
||||
* \author Christian Helmuth
|
||||
* \date 2013-11-11
|
||||
*/
|
||||
|
||||
#ifndef _NODE_H_
|
||||
#define _NODE_H_
|
||||
|
||||
/* Genode includes */
|
||||
#include <util/list.h>
|
||||
#include <base/lock.h>
|
||||
#include <base/signal.h>
|
||||
|
||||
|
||||
namespace File_system {
|
||||
|
||||
class Listener : public List<Listener>::Element
|
||||
{
|
||||
private:
|
||||
|
||||
Lock _lock;
|
||||
Signal_context_capability _sigh;
|
||||
bool _marked_as_updated;
|
||||
|
||||
public:
|
||||
|
||||
Listener() : _marked_as_updated(false) { }
|
||||
|
||||
Listener(Signal_context_capability sigh)
|
||||
: _sigh(sigh), _marked_as_updated(false) { }
|
||||
|
||||
void notify()
|
||||
{
|
||||
Lock::Guard guard(_lock);
|
||||
|
||||
if (_marked_as_updated && _sigh.valid())
|
||||
Signal_transmitter(_sigh).submit();
|
||||
|
||||
_marked_as_updated = false;
|
||||
}
|
||||
|
||||
void mark_as_updated()
|
||||
{
|
||||
Lock::Guard guard(_lock);
|
||||
|
||||
_marked_as_updated = true;
|
||||
}
|
||||
|
||||
bool valid() const { return _sigh.valid(); }
|
||||
};
|
||||
|
||||
|
||||
class Node : public List<Node>::Element
|
||||
{
|
||||
public:
|
||||
|
||||
typedef char Name[128];
|
||||
|
||||
private:
|
||||
|
||||
Lock _lock;
|
||||
Name _name;
|
||||
unsigned long const _inode;
|
||||
|
||||
List<Listener> _listeners;
|
||||
|
||||
public:
|
||||
|
||||
Node(unsigned long inode) : _inode(inode) { _name[0] = 0; }
|
||||
|
||||
virtual ~Node()
|
||||
{
|
||||
/* propagate event to listeners */
|
||||
mark_as_updated();
|
||||
notify_listeners();
|
||||
|
||||
while (_listeners.first())
|
||||
_listeners.remove(_listeners.first());
|
||||
}
|
||||
|
||||
unsigned long inode() const { return _inode; }
|
||||
char const *name() const { return _name; }
|
||||
|
||||
/**
|
||||
* Assign name
|
||||
*/
|
||||
void name(char const *name) { strncpy(_name, name, sizeof(_name)); }
|
||||
|
||||
void lock() { _lock.lock(); }
|
||||
void unlock() { _lock.unlock(); }
|
||||
|
||||
virtual size_t read(char *dst, size_t len, seek_off_t) = 0;
|
||||
virtual size_t write(char const *src, size_t len, seek_off_t) = 0;
|
||||
|
||||
void add_listener(Listener *listener)
|
||||
{
|
||||
_listeners.insert(listener);
|
||||
}
|
||||
|
||||
void remove_listener(Listener *listener)
|
||||
{
|
||||
_listeners.remove(listener);
|
||||
}
|
||||
|
||||
void notify_listeners()
|
||||
{
|
||||
for (Listener *curr = _listeners.first(); curr; curr = curr->next())
|
||||
curr->notify();
|
||||
}
|
||||
|
||||
void mark_as_updated()
|
||||
{
|
||||
for (Listener *curr = _listeners.first(); curr; curr = curr->next())
|
||||
curr->mark_as_updated();
|
||||
}
|
||||
};
|
||||
|
||||
|
||||
/**
|
||||
* Guard used for properly releasing node locks
|
||||
*/
|
||||
struct Node_lock_guard
|
||||
{
|
||||
Node &node;
|
||||
|
||||
Node_lock_guard(Node &node) : node(node) { }
|
||||
|
||||
~Node_lock_guard() { node.unlock(); }
|
||||
};
|
||||
}
|
||||
|
||||
#endif /* _NODE_H_ */
|
||||
|
|
@ -0,0 +1,198 @@
|
|||
/*
|
||||
* \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];
|
||||
|
||||
/**
|
||||
* Each open node handle can act as a listener to be informed about
|
||||
* node changes.
|
||||
*/
|
||||
Listener _listeners[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))
|
||||
return;
|
||||
|
||||
/*
|
||||
* Notify listeners about the changed file.
|
||||
*/
|
||||
Node *node = dynamic_cast<Node *>(_nodes[handle.value]);
|
||||
if (!node) { return; }
|
||||
|
||||
node->lock();
|
||||
node->notify_listeners();
|
||||
|
||||
/*
|
||||
* De-allocate handle
|
||||
*/
|
||||
Listener &listener = _listeners[handle.value];
|
||||
|
||||
if (listener.valid())
|
||||
node->remove_listener(&listener);
|
||||
|
||||
_nodes[handle.value] = 0;
|
||||
listener = Listener();
|
||||
|
||||
node->unlock();
|
||||
}
|
||||
|
||||
/**
|
||||
* Lookup node using its handle as key
|
||||
*
|
||||
* The node returned by this function is in a locked state.
|
||||
*
|
||||
* \throw Invalid_handle
|
||||
*/
|
||||
template <typename HANDLE_TYPE>
|
||||
typename Node_type<HANDLE_TYPE>::Type *lookup_and_lock(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();
|
||||
|
||||
node->lock();
|
||||
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)) {
|
||||
PDBG("refer_to_same_node -> Invalid_handle");
|
||||
throw Invalid_handle();
|
||||
}
|
||||
|
||||
return _nodes[h1.value] == _nodes[h2.value];
|
||||
}
|
||||
|
||||
/**
|
||||
* Register signal handler to be notified of node changes
|
||||
*/
|
||||
void sigh(Node_handle handle, Signal_context_capability sigh)
|
||||
{
|
||||
Lock::Guard guard(_lock);
|
||||
|
||||
if (!_in_range(handle.value))
|
||||
throw Invalid_handle();
|
||||
|
||||
Node *node = dynamic_cast<Node *>(_nodes[handle.value]);
|
||||
if (!node) {
|
||||
PDBG("Invalid_handle");
|
||||
throw Invalid_handle();
|
||||
}
|
||||
|
||||
node->lock();
|
||||
Node_lock_guard node_lock_guard(*node);
|
||||
|
||||
Listener &listener = _listeners[handle.value];
|
||||
|
||||
/*
|
||||
* If there was already a handler registered for the node,
|
||||
* remove the old handler.
|
||||
*/
|
||||
if (listener.valid())
|
||||
node->remove_listener(&listener);
|
||||
|
||||
/*
|
||||
* Register new handler
|
||||
*/
|
||||
listener = Listener(sigh);
|
||||
node->add_listener(&listener);
|
||||
}
|
||||
};
|
||||
}
|
||||
|
||||
#endif /* _NODE_HANDLE_REGISTRY_H_ */
|
||||
|
|
@ -0,0 +1,50 @@
|
|||
/*
|
||||
* \brief Symlink file-system node
|
||||
* \author Norman Feske
|
||||
* \author Christian Helmuth
|
||||
* \date 2013-11-11
|
||||
*
|
||||
* FIXME unfinished
|
||||
*/
|
||||
|
||||
#ifndef _SYMLINK_H_
|
||||
#define _SYMLINK_H_
|
||||
|
||||
/* local includes */
|
||||
#include <node.h>
|
||||
#include <lx_util.h>
|
||||
|
||||
|
||||
namespace File_system {
|
||||
class Symlink;
|
||||
}
|
||||
|
||||
|
||||
class File_system::Symlink : public Node
|
||||
{
|
||||
private:
|
||||
|
||||
char _link_to[MAX_PATH_LEN];
|
||||
|
||||
public:
|
||||
|
||||
Symlink(char const *name) { Node::name(name); }
|
||||
|
||||
size_t read(char *dst, size_t len, seek_off_t seek_offset)
|
||||
{
|
||||
size_t count = min(len, sizeof(_link_to) + 1);
|
||||
Genode::strncpy(dst, _link_to, count);
|
||||
return count;
|
||||
}
|
||||
|
||||
size_t write(char const *src, size_t len, seek_off_t seek_offset)
|
||||
{
|
||||
size_t count = min(len, sizeof(_link_to) + 1);
|
||||
Genode::strncpy(_link_to, src, count);
|
||||
return count;
|
||||
}
|
||||
|
||||
file_size_t length() const { return strlen(_link_to) + 1; }
|
||||
};
|
||||
|
||||
#endif /* _SYMLINK_H_ */
|
||||
|
|
@ -0,0 +1,6 @@
|
|||
TARGET = lx_fs
|
||||
REQUIRES = linux
|
||||
SRC_CC = main.cc
|
||||
LIBS = base config server lx_hybrid
|
||||
|
||||
INC_DIR += $(PRG_DIR) /usr/include
|
||||
|
|
@ -0,0 +1,63 @@
|
|||
/*
|
||||
* \brief Utilities
|
||||
* \author Norman Feske
|
||||
* \date 2012-04-11
|
||||
*/
|
||||
|
||||
#ifndef _UTIL_H_
|
||||
#define _UTIL_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 'str' is a valid node name
|
||||
*/
|
||||
static inline bool valid_name(char const *str)
|
||||
{
|
||||
if (string_contains(str, '/')) return false;
|
||||
|
||||
/* must have at least one character */
|
||||
if (str[0] == 0) return false;
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
#endif /* _UTIL_H_ */
|
||||
Loading…
Reference in New Issue