--- /dev/null
+/*
+ FUSE: Filesystem in Userspace
+ Copyright (C) 2001-2005 Miklos Szeredi <miklos@szeredi.hu>
+
+ This program can be distributed under the terms of the GNU GPL.
+ See the file COPYING.
+*/
+
+#include <linux/fuse.h>
+#include <linux/fs.h>
+#include <linux/wait.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/mm.h>
+#include <linux/backing-dev.h>
+#include <asm/semaphore.h>
+
+/** FUSE inode */
+struct fuse_inode {
+ /** Inode data */
+ struct inode inode;
+
+ /** Unique ID, which identifies the inode between userspace
+ * and kernel */
+ u64 nodeid;
+
+ /** Time in jiffies until the file attributes are valid */
+ unsigned long i_time;
+};
+
+/**
+ * A Fuse connection.
+ *
+ * This structure is created, when the filesystem is mounted, and is
+ * destroyed, when the client device is closed and the filesystem is
+ * unmounted.
+ */
+struct fuse_conn {
+ /** The superblock of the mounted filesystem */
+ struct super_block *sb;
+
+ /** The user id for this mount */
+ uid_t user_id;
+
+ /** Backing dev info */
+ struct backing_dev_info bdi;
+};
+
+static inline struct fuse_conn **get_fuse_conn_super_p(struct super_block *sb)
+{
+ return (struct fuse_conn **) &sb->s_fs_info;
+}
+
+static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
+{
+ return *get_fuse_conn_super_p(sb);
+}
+
+static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
+{
+ return get_fuse_conn_super(inode->i_sb);
+}
+
+static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
+{
+ return container_of(inode, struct fuse_inode, inode);
+}
+
+static inline u64 get_node_id(struct inode *inode)
+{
+ return get_fuse_inode(inode)->nodeid;
+}
+
+/**
+ * This is the single global spinlock which protects FUSE's structures
+ *
+ * The following data is protected by this lock:
+ *
+ * - the s_fs_info field of the super block
+ * - the sb (super_block) field in fuse_conn
+ */
+extern spinlock_t fuse_lock;
+
+/**
+ * Check if the connection can be released, and if yes, then free the
+ * connection structure
+ */
+void fuse_release_conn(struct fuse_conn *fc);
+
--- /dev/null
+/*
+ FUSE: Filesystem in Userspace
+ Copyright (C) 2001-2005 Miklos Szeredi <miklos@szeredi.hu>
+
+ This program can be distributed under the terms of the GNU GPL.
+ See the file COPYING.
+*/
+
+#include "fuse_i.h"
+
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/mount.h>
+#include <linux/seq_file.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/parser.h>
+#include <linux/statfs.h>
+
+MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
+MODULE_DESCRIPTION("Filesystem in Userspace");
+MODULE_LICENSE("GPL");
+
+spinlock_t fuse_lock;
+static kmem_cache_t *fuse_inode_cachep;
+static int mount_count;
+
+static int mount_max = 1000;
+module_param(mount_max, int, 0644);
+MODULE_PARM_DESC(mount_max, "Maximum number of FUSE mounts allowed, if -1 then unlimited (default: 1000)");
+
+#define FUSE_SUPER_MAGIC 0x65735546
+
+struct fuse_mount_data {
+ int fd;
+ unsigned rootmode;
+ unsigned user_id;
+};
+
+static struct inode *fuse_alloc_inode(struct super_block *sb)
+{
+ struct inode *inode;
+ struct fuse_inode *fi;
+
+ inode = kmem_cache_alloc(fuse_inode_cachep, SLAB_KERNEL);
+ if (!inode)
+ return NULL;
+
+ fi = get_fuse_inode(inode);
+ fi->i_time = jiffies - 1;
+ fi->nodeid = 0;
+
+ return inode;
+}
+
+static void fuse_destroy_inode(struct inode *inode)
+{
+ kmem_cache_free(fuse_inode_cachep, inode);
+}
+
+static void fuse_read_inode(struct inode *inode)
+{
+ /* No op */
+}
+
+static void fuse_clear_inode(struct inode *inode)
+{
+}
+
+void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
+{
+ if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size)
+ invalidate_inode_pages(inode->i_mapping);
+
+ inode->i_ino = attr->ino;
+ inode->i_mode = (inode->i_mode & S_IFMT) + (attr->mode & 07777);
+ inode->i_nlink = attr->nlink;
+ inode->i_uid = attr->uid;
+ inode->i_gid = attr->gid;
+ i_size_write(inode, attr->size);
+ inode->i_blksize = PAGE_CACHE_SIZE;
+ inode->i_blocks = attr->blocks;
+ inode->i_atime.tv_sec = attr->atime;
+ inode->i_atime.tv_nsec = attr->atimensec;
+ inode->i_mtime.tv_sec = attr->mtime;
+ inode->i_mtime.tv_nsec = attr->mtimensec;
+ inode->i_ctime.tv_sec = attr->ctime;
+ inode->i_ctime.tv_nsec = attr->ctimensec;
+}
+
+static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
+{
+ inode->i_mode = attr->mode & S_IFMT;
+ i_size_write(inode, attr->size);
+}
+
+static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
+{
+ unsigned long nodeid = *(unsigned long *) _nodeidp;
+ if (get_node_id(inode) == nodeid)
+ return 1;
+ else
+ return 0;
+}
+
+static int fuse_inode_set(struct inode *inode, void *_nodeidp)
+{
+ unsigned long nodeid = *(unsigned long *) _nodeidp;
+ get_fuse_inode(inode)->nodeid = nodeid;
+ return 0;
+}
+
+struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
+ int generation, struct fuse_attr *attr, int version)
+{
+ struct inode *inode;
+ struct fuse_conn *fc = get_fuse_conn_super(sb);
+ int retried = 0;
+
+ retry:
+ inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
+ if (!inode)
+ return NULL;
+
+ if ((inode->i_state & I_NEW)) {
+ inode->i_generation = generation;
+ inode->i_data.backing_dev_info = &fc->bdi;
+ fuse_init_inode(inode, attr);
+ unlock_new_inode(inode);
+ } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
+ BUG_ON(retried);
+ /* Inode has changed type, any I/O on the old should fail */
+ make_bad_inode(inode);
+ iput(inode);
+ retried = 1;
+ goto retry;
+ }
+
+ fuse_change_attributes(inode, attr);
+ inode->i_version = version;
+ return inode;
+}
+
+static void fuse_put_super(struct super_block *sb)
+{
+ struct fuse_conn *fc = get_fuse_conn_super(sb);
+
+ spin_lock(&fuse_lock);
+ mount_count --;
+ fc->sb = NULL;
+ fc->user_id = 0;
+ fuse_release_conn(fc);
+ *get_fuse_conn_super_p(sb) = NULL;
+ spin_unlock(&fuse_lock);
+}
+
+enum {
+ OPT_FD,
+ OPT_ROOTMODE,
+ OPT_USER_ID,
+ OPT_DEFAULT_PERMISSIONS,
+ OPT_ALLOW_OTHER,
+ OPT_ALLOW_ROOT,
+ OPT_KERNEL_CACHE,
+ OPT_ERR
+};
+
+static match_table_t tokens = {
+ {OPT_FD, "fd=%u"},
+ {OPT_ROOTMODE, "rootmode=%o"},
+ {OPT_USER_ID, "user_id=%u"},
+ {OPT_DEFAULT_PERMISSIONS, "default_permissions"},
+ {OPT_ALLOW_OTHER, "allow_other"},
+ {OPT_ALLOW_ROOT, "allow_root"},
+ {OPT_KERNEL_CACHE, "kernel_cache"},
+ {OPT_ERR, NULL}
+};
+
+static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
+{
+ char *p;
+ memset(d, 0, sizeof(struct fuse_mount_data));
+ d->fd = -1;
+
+ while ((p = strsep(&opt, ",")) != NULL) {
+ int token;
+ int value;
+ substring_t args[MAX_OPT_ARGS];
+ if (!*p)
+ continue;
+
+ token = match_token(p, tokens, args);
+ switch (token) {
+ case OPT_FD:
+ if (match_int(&args[0], &value))
+ return 0;
+ d->fd = value;
+ break;
+
+ case OPT_ROOTMODE:
+ if (match_octal(&args[0], &value))
+ return 0;
+ d->rootmode = value;
+ break;
+
+ case OPT_USER_ID:
+ if (match_int(&args[0], &value))
+ return 0;
+ d->user_id = value;
+ break;
+
+ default:
+ return 0;
+ }
+ }
+ if (d->fd == -1)
+ return 0;
+
+ return 1;
+}
+
+static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
+{
+ struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
+
+ seq_printf(m, ",user_id=%u", fc->user_id);
+ return 0;
+}
+
+void fuse_release_conn(struct fuse_conn *fc)
+{
+ kfree(fc);
+}
+
+static struct fuse_conn *new_conn(void)
+{
+ struct fuse_conn *fc;
+
+ fc = kmalloc(sizeof(*fc), GFP_KERNEL);
+ if (fc != NULL) {
+ memset(fc, 0, sizeof(*fc));
+ fc->sb = NULL;
+ fc->user_id = 0;
+ fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
+ fc->bdi.unplug_io_fn = default_unplug_io_fn;
+ }
+ return fc;
+}
+
+static struct fuse_conn *get_conn(struct file *file, struct super_block *sb)
+{
+ struct fuse_conn *fc;
+
+ fc = new_conn();
+ if (fc == NULL)
+ return NULL;
+ spin_lock(&fuse_lock);
+ fc->sb = sb;
+ spin_unlock(&fuse_lock);
+ return fc;
+}
+
+static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
+{
+ struct fuse_attr attr;
+ memset(&attr, 0, sizeof(attr));
+
+ attr.mode = mode;
+ attr.ino = FUSE_ROOT_ID;
+ return fuse_iget(sb, 1, 0, &attr, 0);
+}
+
+static struct super_operations fuse_super_operations = {
+ .alloc_inode = fuse_alloc_inode,
+ .destroy_inode = fuse_destroy_inode,
+ .read_inode = fuse_read_inode,
+ .clear_inode = fuse_clear_inode,
+ .put_super = fuse_put_super,
+ .show_options = fuse_show_options,
+};
+
+static int inc_mount_count(void)
+{
+ int success = 0;
+ spin_lock(&fuse_lock);
+ mount_count ++;
+ if (mount_max == -1 || mount_count <= mount_max)
+ success = 1;
+ spin_unlock(&fuse_lock);
+ return success;
+}
+
+static int fuse_fill_super(struct super_block *sb, void *data, int silent)
+{
+ struct fuse_conn *fc;
+ struct inode *root;
+ struct fuse_mount_data d;
+ struct file *file;
+ int err;
+
+ if (!parse_fuse_opt((char *) data, &d))
+ return -EINVAL;
+
+ sb->s_blocksize = PAGE_CACHE_SIZE;
+ sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ sb->s_magic = FUSE_SUPER_MAGIC;
+ sb->s_op = &fuse_super_operations;
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
+
+ file = fget(d.fd);
+ if (!file)
+ return -EINVAL;
+
+ fc = get_conn(file, sb);
+ fput(file);
+ if (fc == NULL)
+ return -EINVAL;
+
+ fc->user_id = d.user_id;
+
+ *get_fuse_conn_super_p(sb) = fc;
+
+ err = -ENFILE;
+ if (!inc_mount_count() && current->uid != 0)
+ goto err;
+
+ err = -ENOMEM;
+ root = get_root_inode(sb, d.rootmode);
+ if (root == NULL)
+ goto err;
+
+ sb->s_root = d_alloc_root(root);
+ if (!sb->s_root) {
+ iput(root);
+ goto err;
+ }
+ return 0;
+
+ err:
+ spin_lock(&fuse_lock);
+ mount_count --;
+ fc->sb = NULL;
+ fuse_release_conn(fc);
+ spin_unlock(&fuse_lock);
+ *get_fuse_conn_super_p(sb) = NULL;
+ return err;
+}
+
+static struct super_block *fuse_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *raw_data)
+{
+ return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super);
+}
+
+static struct file_system_type fuse_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "fuse",
+ .get_sb = fuse_get_sb,
+ .kill_sb = kill_anon_super,
+};
+
+static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep,
+ unsigned long flags)
+{
+ struct inode * inode = foo;
+
+ if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
+ SLAB_CTOR_CONSTRUCTOR)
+ inode_init_once(inode);
+}
+
+static int __init fuse_fs_init(void)
+{
+ int err;
+
+ err = register_filesystem(&fuse_fs_type);
+ if (err)
+ printk("fuse: failed to register filesystem\n");
+ else {
+ fuse_inode_cachep = kmem_cache_create("fuse_inode",
+ sizeof(struct fuse_inode),
+ 0, SLAB_HWCACHE_ALIGN,
+ fuse_inode_init_once, NULL);
+ if (!fuse_inode_cachep) {
+ unregister_filesystem(&fuse_fs_type);
+ err = -ENOMEM;
+ }
+ }
+
+ return err;
+}
+
+static void fuse_fs_cleanup(void)
+{
+ unregister_filesystem(&fuse_fs_type);
+ kmem_cache_destroy(fuse_inode_cachep);
+}
+
+static int __init fuse_init(void)
+{
+ int res;
+
+ printk("fuse init (API version %i.%i)\n",
+ FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
+
+ spin_lock_init(&fuse_lock);
+ res = fuse_fs_init();
+ if (res)
+ goto err;
+
+ return 0;
+
+ err:
+ return res;
+}
+
+static void __exit fuse_exit(void)
+{
+ printk(KERN_DEBUG "fuse exit\n");
+
+ fuse_fs_cleanup();
+}
+
+module_init(fuse_init);
+module_exit(fuse_exit);
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