213 lines
6.4 KiB
C++
213 lines
6.4 KiB
C++
/*
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* \brief Libc plugin for using a process-local virtual file system
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* \author Norman Feske
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* \author Emery Hemingway
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* \author Christian Helmuth
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* \date 2014-04-09
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*/
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/*
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* Copyright (C) 2014-2017 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 Affero General Public License version 3.
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*/
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#ifndef _LIBC_VFS__PLUGIN_H_
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#define _LIBC_VFS__PLUGIN_H_
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/* Genode includes */
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#include <libc/component.h>
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#include "task.h"
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/* libc includes */
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#include <fcntl.h>
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#include <unistd.h>
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/* libc plugin interface */
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#include <libc-plugin/plugin.h>
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#include <libc-plugin/fd_alloc.h>
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namespace Libc { class Vfs_plugin; }
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class Libc::Vfs_plugin : public Libc::Plugin
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{
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private:
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Genode::Allocator &_alloc;
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Vfs::File_system &_root_dir;
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void _open_stdio(Genode::Xml_node const &node, char const *attr,
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int libc_fd, unsigned flags)
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{
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try {
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Genode::String<Vfs::MAX_PATH_LEN> path;
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struct stat out_stat;
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node.attribute(attr).value(&path);
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if (stat(path.string(), &out_stat) != 0)
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return;
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Libc::File_descriptor *fd = open(path.string(), flags, libc_fd);
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if (fd->libc_fd != libc_fd) {
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Genode::error("could not allocate fd ",libc_fd," for ",path,", "
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"got fd ",fd->libc_fd);
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close(fd);
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return;
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}
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/*
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* We need to manually register the path. Normally this is done
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* by '_open'. But we call the local 'open' function directly
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* because we want to explicitly specify the libc fd ID.
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*
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* We have to allocate the path from the libc (done via 'strdup')
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* such that the path can be freed when an stdio fd is closed.
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*/
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if (fd->fd_path) { Genode::warning("may leak former FD path memory"); }
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fd->fd_path = strdup(path.string());
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} catch (Xml_node::Nonexistent_attribute) { }
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}
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void _vfs_sync(Vfs::Vfs_handle *vfs_handle)
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{
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{
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struct Check : Libc::Suspend_functor
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{
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bool retry { false };
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Vfs::Vfs_handle *vfs_handle;
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Check(Vfs::Vfs_handle *vfs_handle)
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: vfs_handle(vfs_handle) { }
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bool suspend() override
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{
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retry = !vfs_handle->fs().queue_sync(vfs_handle);
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return retry;
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}
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} check(vfs_handle);
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/*
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* Cannot call Libc::suspend() immediately, because the Libc kernel
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* might not be running yet.
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*/
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if (!vfs_handle->fs().queue_sync(vfs_handle)) {
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do {
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Libc::suspend(check);
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} while (check.retry);
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}
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}
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{
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struct Check : Libc::Suspend_functor
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{
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bool retry { false };
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Vfs::Vfs_handle *vfs_handle;
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Check(Vfs::Vfs_handle *vfs_handle)
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: vfs_handle(vfs_handle) { }
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bool suspend() override
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{
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retry = (vfs_handle->fs().complete_sync(vfs_handle) ==
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Vfs::File_io_service::SYNC_QUEUED);
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return retry;
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}
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} check(vfs_handle);
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/*
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* Cannot call Libc::suspend() immediately, because the Libc kernel
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* might not be running yet.
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*/
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if (vfs_handle->fs().complete_sync(vfs_handle) ==
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Vfs::File_io_service::SYNC_QUEUED) {
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do {
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Libc::suspend(check);
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} while (check.retry);
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}
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}
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}
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public:
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Vfs_plugin(Libc::Env &env, Genode::Allocator &alloc)
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:
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_alloc(alloc), _root_dir(env.vfs())
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{
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using Genode::Xml_node;
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if (_root_dir.num_dirent("/"))
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env.config([&] (Xml_node const &top) {
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try {
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Xml_node const node = top.sub_node("libc");
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try {
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Genode::String<Vfs::MAX_PATH_LEN> path;
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node.attribute("cwd").value(&path);
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chdir(path.string());
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} catch (Xml_node::Nonexistent_attribute) { }
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_open_stdio(node, "stdin", 0, O_RDONLY);
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_open_stdio(node, "stdout", 1, O_WRONLY);
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_open_stdio(node, "stderr", 2, O_WRONLY);
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} catch (Xml_node::Nonexistent_sub_node) { }
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});
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}
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~Vfs_plugin() final { }
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bool supports_access(const char *, int) override { return true; }
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bool supports_mkdir(const char *, mode_t) override { return true; }
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bool supports_open(const char *, int) override { return true; }
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bool supports_readlink(const char *, char *, ::size_t) override { return true; }
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bool supports_rename(const char *, const char *) override { return true; }
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bool supports_rmdir(const char *) override { return true; }
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bool supports_stat(const char *) override { return true; }
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bool supports_symlink(const char *, const char *) override { return true; }
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bool supports_unlink(const char *) override { return true; }
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bool supports_mmap() override { return true; }
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bool supports_select(int nfds,
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fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
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struct timeval *timeout) override;
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Libc::File_descriptor *open(const char *, int, int libc_fd);
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Libc::File_descriptor *open(const char *path, int flags) override
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{
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return open(path, flags, Libc::ANY_FD);
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}
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int access(char const *, int) override;
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int close(Libc::File_descriptor *) override;
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int dup2(Libc::File_descriptor *, Libc::File_descriptor *) override;
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int fcntl(Libc::File_descriptor *, int, long) override;
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int fstat(Libc::File_descriptor *, struct stat *) override;
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int fstatfs(Libc::File_descriptor *, struct statfs *) override;
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int fsync(Libc::File_descriptor *fd) override;
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int ftruncate(Libc::File_descriptor *, ::off_t) override;
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ssize_t getdirentries(Libc::File_descriptor *, char *, ::size_t , ::off_t *) override;
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int ioctl(Libc::File_descriptor *, int , char *) override;
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::off_t lseek(Libc::File_descriptor *fd, ::off_t offset, int whence) override;
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int mkdir(const char *, mode_t) override;
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ssize_t read(Libc::File_descriptor *, void *, ::size_t) override;
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ssize_t readlink(const char *, char *, ::size_t) override;
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int rename(const char *, const char *) override;
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int rmdir(const char *) override;
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int stat(const char *, struct stat *) override;
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int symlink(const char *, const char *) override;
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int unlink(const char *) override;
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ssize_t write(Libc::File_descriptor *, const void *, ::size_t ) override;
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void *mmap(void *, ::size_t, int, int, Libc::File_descriptor *, ::off_t) override;
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int munmap(void *, ::size_t) override;
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int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout) override;
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};
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#endif
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