diff options
Diffstat (limited to 'fs/fuse/dir.c')
| -rw-r--r-- | fs/fuse/dir.c | 413 |
1 files changed, 413 insertions, 0 deletions
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c new file mode 100644 index 000000000000..a89730e70c58 --- /dev/null +++ b/fs/fuse/dir.c @@ -0,0 +1,413 @@ +/* + 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/file.h> +#include <linux/gfp.h> +#include <linux/sched.h> +#include <linux/namei.h> + +static inline unsigned long time_to_jiffies(unsigned long sec, + unsigned long nsec) +{ + struct timespec ts = {sec, nsec}; + return jiffies + timespec_to_jiffies(&ts); +} + +static void fuse_lookup_init(struct fuse_req *req, struct inode *dir, + struct dentry *entry, + struct fuse_entry_out *outarg) +{ + req->in.h.opcode = FUSE_LOOKUP; + req->in.h.nodeid = get_node_id(dir); + req->inode = dir; + req->in.numargs = 1; + req->in.args[0].size = entry->d_name.len + 1; + req->in.args[0].value = entry->d_name.name; + req->out.numargs = 1; + req->out.args[0].size = sizeof(struct fuse_entry_out); + req->out.args[0].value = outarg; +} + +static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd) +{ + if (!entry->d_inode || is_bad_inode(entry->d_inode)) + return 0; + else if (time_after(jiffies, entry->d_time)) { + int err; + int version; + struct fuse_entry_out outarg; + struct inode *inode = entry->d_inode; + struct fuse_inode *fi = get_fuse_inode(inode); + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req = fuse_get_request_nonint(fc); + if (!req) + return 0; + + fuse_lookup_init(req, entry->d_parent->d_inode, entry, &outarg); + request_send_nonint(fc, req); + version = req->out.h.unique; + err = req->out.h.error; + fuse_put_request(fc, req); + if (err || outarg.nodeid != get_node_id(inode) || + (outarg.attr.mode ^ inode->i_mode) & S_IFMT) + return 0; + + fuse_change_attributes(inode, &outarg.attr); + inode->i_version = version; + entry->d_time = time_to_jiffies(outarg.entry_valid, + outarg.entry_valid_nsec); + fi->i_time = time_to_jiffies(outarg.attr_valid, + outarg.attr_valid_nsec); + } + return 1; +} + +static struct dentry_operations fuse_dentry_operations = { + .d_revalidate = fuse_dentry_revalidate, +}; + +static int fuse_lookup_iget(struct inode *dir, struct dentry *entry, + struct inode **inodep) +{ + int err; + int version; + struct fuse_entry_out outarg; + struct inode *inode = NULL; + struct fuse_conn *fc = get_fuse_conn(dir); + struct fuse_req *req; + + if (entry->d_name.len > FUSE_NAME_MAX) + return -ENAMETOOLONG; + + req = fuse_get_request(fc); + if (!req) + return -ERESTARTNOINTR; + + fuse_lookup_init(req, dir, entry, &outarg); + request_send(fc, req); + version = req->out.h.unique; + err = req->out.h.error; + if (!err) { + inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation, + &outarg.attr, version); + if (!inode) { + fuse_send_forget(fc, req, outarg.nodeid, version); + return -ENOMEM; + } + } + fuse_put_request(fc, req); + if (err && err != -ENOENT) + return err; + + if (inode) { + struct fuse_inode *fi = get_fuse_inode(inode); + entry->d_time = time_to_jiffies(outarg.entry_valid, + outarg.entry_valid_nsec); + fi->i_time = time_to_jiffies(outarg.attr_valid, + outarg.attr_valid_nsec); + } + + entry->d_op = &fuse_dentry_operations; + *inodep = inode; + return 0; +} + +int fuse_do_getattr(struct inode *inode) +{ + int err; + struct fuse_attr_out arg; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req = fuse_get_request(fc); + if (!req) + return -ERESTARTNOINTR; + + req->in.h.opcode = FUSE_GETATTR; + req->in.h.nodeid = get_node_id(inode); + req->inode = inode; + req->out.numargs = 1; + req->out.args[0].size = sizeof(arg); + req->out.args[0].value = &arg; + request_send(fc, req); + err = req->out.h.error; + fuse_put_request(fc, req); + if (!err) { + if ((inode->i_mode ^ arg.attr.mode) & S_IFMT) { + make_bad_inode(inode); + err = -EIO; + } else { + struct fuse_inode *fi = get_fuse_inode(inode); + fuse_change_attributes(inode, &arg.attr); + fi->i_time = time_to_jiffies(arg.attr_valid, + arg.attr_valid_nsec); + } + } + return err; +} + +static int fuse_revalidate(struct dentry *entry) +{ + struct inode *inode = entry->d_inode; + struct fuse_inode *fi = get_fuse_inode(inode); + struct fuse_conn *fc = get_fuse_conn(inode); + + if (get_node_id(inode) == FUSE_ROOT_ID) { + if (current->fsuid != fc->user_id) + return -EACCES; + } else if (time_before_eq(jiffies, fi->i_time)) + return 0; + + return fuse_do_getattr(inode); +} + +static int fuse_permission(struct inode *inode, int mask, struct nameidata *nd) +{ + struct fuse_conn *fc = get_fuse_conn(inode); + + if (current->fsuid != fc->user_id) + return -EACCES; + else { + int mode = inode->i_mode; + if ((mask & MAY_WRITE) && IS_RDONLY(inode) && + (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) + return -EROFS; + if ((mask & MAY_EXEC) && !S_ISDIR(mode) && !(mode & S_IXUGO)) + return -EACCES; + return 0; + } +} + +static int parse_dirfile(char *buf, size_t nbytes, struct file *file, + void *dstbuf, filldir_t filldir) +{ + while (nbytes >= FUSE_NAME_OFFSET) { + struct fuse_dirent *dirent = (struct fuse_dirent *) buf; + size_t reclen = FUSE_DIRENT_SIZE(dirent); + int over; + if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX) + return -EIO; + if (reclen > nbytes) + break; + + over = filldir(dstbuf, dirent->name, dirent->namelen, + file->f_pos, dirent->ino, dirent->type); + if (over) + break; + + buf += reclen; + nbytes -= reclen; + file->f_pos = dirent->off; + } + + return 0; +} + +static int fuse_checkdir(struct file *cfile, struct file *file) +{ + struct inode *inode; + if (!cfile) + return -EIO; + inode = cfile->f_dentry->d_inode; + if (!S_ISREG(inode->i_mode)) { + fput(cfile); + return -EIO; + } + + file->private_data = cfile; + return 0; +} + +static int fuse_getdir(struct file *file) +{ + struct inode *inode = file->f_dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req = fuse_get_request(fc); + struct fuse_getdir_out_i outarg; + int err; + + if (!req) + return -ERESTARTNOINTR; + + req->in.h.opcode = FUSE_GETDIR; + req->in.h.nodeid = get_node_id(inode); + req->inode = inode; + req->out.numargs = 1; + req->out.args[0].size = sizeof(struct fuse_getdir_out); + req->out.args[0].value = &outarg; + request_send(fc, req); + err = req->out.h.error; + fuse_put_request(fc, req); + if (!err) + err = fuse_checkdir(outarg.file, file); + return err; +} + +static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir) +{ + struct file *cfile = file->private_data; + char *buf; + int ret; + + if (!cfile) { + ret = fuse_getdir(file); + if (ret) + return ret; + + cfile = file->private_data; + } + + buf = (char *) __get_free_page(GFP_KERNEL); + if (!buf) + return -ENOMEM; + + ret = kernel_read(cfile, file->f_pos, buf, PAGE_SIZE); + if (ret > 0) + ret = parse_dirfile(buf, ret, file, dstbuf, filldir); + + free_page((unsigned long) buf); + return ret; +} + +static char *read_link(struct dentry *dentry) +{ + struct inode *inode = dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req = fuse_get_request(fc); + char *link; + + if (!req) + return ERR_PTR(-ERESTARTNOINTR); + + link = (char *) __get_free_page(GFP_KERNEL); + if (!link) { + link = ERR_PTR(-ENOMEM); + goto out; + } + req->in.h.opcode = FUSE_READLINK; + req->in.h.nodeid = get_node_id(inode); + req->inode = inode; + req->out.argvar = 1; + req->out.numargs = 1; + req->out.args[0].size = PAGE_SIZE - 1; + req->out.args[0].value = link; + request_send(fc, req); + if (req->out.h.error) { + free_page((unsigned long) link); + link = ERR_PTR(req->out.h.error); + } else + link[req->out.args[0].size] = '\0'; + out: + fuse_put_request(fc, req); + return link; +} + +static void free_link(char *link) +{ + if (!IS_ERR(link)) + free_page((unsigned long) link); +} + +static void *fuse_follow_link(struct dentry *dentry, struct nameidata *nd) +{ + nd_set_link(nd, read_link(dentry)); + return NULL; +} + +static void fuse_put_link(struct dentry *dentry, struct nameidata *nd, void *c) +{ + free_link(nd_get_link(nd)); +} + +static int fuse_dir_open(struct inode *inode, struct file *file) +{ + file->private_data = NULL; + return 0; +} + +static int fuse_dir_release(struct inode *inode, struct file *file) +{ + struct file *cfile = file->private_data; + + if (cfile) + fput(cfile); + + return 0; +} + +static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry, + struct kstat *stat) +{ + struct inode *inode = entry->d_inode; + int err = fuse_revalidate(entry); + if (!err) + generic_fillattr(inode, stat); + + return err; +} + +static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry, + struct nameidata *nd) +{ + struct inode *inode; + int err = fuse_lookup_iget(dir, entry, &inode); + if (err) + return ERR_PTR(err); + if (inode && S_ISDIR(inode->i_mode)) { + /* Don't allow creating an alias to a directory */ + struct dentry *alias = d_find_alias(inode); + if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) { + dput(alias); + iput(inode); + return ERR_PTR(-EIO); + } + } + return d_splice_alias(inode, entry); +} + +static struct inode_operations fuse_dir_inode_operations = { + .lookup = fuse_lookup, + .permission = fuse_permission, + .getattr = fuse_getattr, +}; + +static struct file_operations fuse_dir_operations = { + .read = generic_read_dir, + .readdir = fuse_readdir, + .open = fuse_dir_open, + .release = fuse_dir_release, +}; + +static struct inode_operations fuse_common_inode_operations = { + .permission = fuse_permission, + .getattr = fuse_getattr, +}; + +static struct inode_operations fuse_symlink_inode_operations = { + .follow_link = fuse_follow_link, + .put_link = fuse_put_link, + .readlink = generic_readlink, + .getattr = fuse_getattr, +}; + +void fuse_init_common(struct inode *inode) +{ + inode->i_op = &fuse_common_inode_operations; +} + +void fuse_init_dir(struct inode *inode) +{ + inode->i_op = &fuse_dir_inode_operations; + inode->i_fop = &fuse_dir_operations; +} + +void fuse_init_symlink(struct inode *inode) +{ + inode->i_op = &fuse_symlink_inode_operations; +} |