| /* |
| * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
| * Licensed under the GPL |
| * |
| * Ported the filesystem routines to 2.5. |
| * 2003-02-10 Petr Baudis <pasky@ucw.cz> |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/module.h> |
| #include <linux/mm.h> |
| #include <linux/pagemap.h> |
| #include <linux/statfs.h> |
| #include <linux/slab.h> |
| #include <linux/seq_file.h> |
| #include <linux/mount.h> |
| #include "hostfs.h" |
| #include "init.h" |
| #include "kern.h" |
| |
| struct hostfs_inode_info { |
| char *host_filename; |
| int fd; |
| fmode_t mode; |
| struct inode vfs_inode; |
| }; |
| |
| static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) |
| { |
| return list_entry(inode, struct hostfs_inode_info, vfs_inode); |
| } |
| |
| #define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_path.dentry->d_inode) |
| |
| static int hostfs_d_delete(struct dentry *dentry) |
| { |
| return 1; |
| } |
| |
| static const struct dentry_operations hostfs_dentry_ops = { |
| .d_delete = hostfs_d_delete, |
| }; |
| |
| /* Changed in hostfs_args before the kernel starts running */ |
| static char *root_ino = ""; |
| static int append = 0; |
| |
| #define HOSTFS_SUPER_MAGIC 0x00c0ffee |
| |
| static const struct inode_operations hostfs_iops; |
| static const struct inode_operations hostfs_dir_iops; |
| static const struct address_space_operations hostfs_link_aops; |
| |
| #ifndef MODULE |
| static int __init hostfs_args(char *options, int *add) |
| { |
| char *ptr; |
| |
| ptr = strchr(options, ','); |
| if (ptr != NULL) |
| *ptr++ = '\0'; |
| if (*options != '\0') |
| root_ino = options; |
| |
| options = ptr; |
| while (options) { |
| ptr = strchr(options, ','); |
| if (ptr != NULL) |
| *ptr++ = '\0'; |
| if (*options != '\0') { |
| if (!strcmp(options, "append")) |
| append = 1; |
| else printf("hostfs_args - unsupported option - %s\n", |
| options); |
| } |
| options = ptr; |
| } |
| return 0; |
| } |
| |
| __uml_setup("hostfs=", hostfs_args, |
| "hostfs=<root dir>,<flags>,...\n" |
| " This is used to set hostfs parameters. The root directory argument\n" |
| " is used to confine all hostfs mounts to within the specified directory\n" |
| " tree on the host. If this isn't specified, then a user inside UML can\n" |
| " mount anything on the host that's accessible to the user that's running\n" |
| " it.\n" |
| " The only flag currently supported is 'append', which specifies that all\n" |
| " files opened by hostfs will be opened in append mode.\n\n" |
| ); |
| #endif |
| |
| static char *dentry_name(struct dentry *dentry, int extra) |
| { |
| struct dentry *parent; |
| char *root, *name; |
| int len; |
| |
| len = 0; |
| parent = dentry; |
| while (parent->d_parent != parent) { |
| len += parent->d_name.len + 1; |
| parent = parent->d_parent; |
| } |
| |
| root = HOSTFS_I(parent->d_inode)->host_filename; |
| len += strlen(root); |
| name = kmalloc(len + extra + 1, GFP_KERNEL); |
| if (name == NULL) |
| return NULL; |
| |
| name[len] = '\0'; |
| parent = dentry; |
| while (parent->d_parent != parent) { |
| len -= parent->d_name.len + 1; |
| name[len] = '/'; |
| strncpy(&name[len + 1], parent->d_name.name, |
| parent->d_name.len); |
| parent = parent->d_parent; |
| } |
| strncpy(name, root, strlen(root)); |
| return name; |
| } |
| |
| static char *inode_name(struct inode *ino, int extra) |
| { |
| struct dentry *dentry; |
| |
| dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias); |
| return dentry_name(dentry, extra); |
| } |
| |
| static int read_name(struct inode *ino, char *name) |
| { |
| /* |
| * The non-int inode fields are copied into ints by stat_file and |
| * then copied into the inode because passing the actual pointers |
| * in and having them treated as int * breaks on big-endian machines |
| */ |
| int err; |
| int i_mode, i_nlink, i_blksize; |
| unsigned long long i_size; |
| unsigned long long i_ino; |
| unsigned long long i_blocks; |
| |
| err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid, |
| &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime, |
| &ino->i_ctime, &i_blksize, &i_blocks, -1); |
| if (err) |
| return err; |
| |
| ino->i_ino = i_ino; |
| ino->i_mode = i_mode; |
| ino->i_nlink = i_nlink; |
| ino->i_size = i_size; |
| ino->i_blocks = i_blocks; |
| return 0; |
| } |
| |
| static char *follow_link(char *link) |
| { |
| int len, n; |
| char *name, *resolved, *end; |
| |
| len = 64; |
| while (1) { |
| n = -ENOMEM; |
| name = kmalloc(len, GFP_KERNEL); |
| if (name == NULL) |
| goto out; |
| |
| n = hostfs_do_readlink(link, name, len); |
| if (n < len) |
| break; |
| len *= 2; |
| kfree(name); |
| } |
| if (n < 0) |
| goto out_free; |
| |
| if (*name == '/') |
| return name; |
| |
| end = strrchr(link, '/'); |
| if (end == NULL) |
| return name; |
| |
| *(end + 1) = '\0'; |
| len = strlen(link) + strlen(name) + 1; |
| |
| resolved = kmalloc(len, GFP_KERNEL); |
| if (resolved == NULL) { |
| n = -ENOMEM; |
| goto out_free; |
| } |
| |
| sprintf(resolved, "%s%s", link, name); |
| kfree(name); |
| kfree(link); |
| return resolved; |
| |
| out_free: |
| kfree(name); |
| out: |
| return ERR_PTR(n); |
| } |
| |
| static int hostfs_read_inode(struct inode *ino) |
| { |
| char *name; |
| int err = 0; |
| |
| /* |
| * Unfortunately, we are called from iget() when we don't have a dentry |
| * allocated yet. |
| */ |
| if (list_empty(&ino->i_dentry)) |
| goto out; |
| |
| err = -ENOMEM; |
| name = inode_name(ino, 0); |
| if (name == NULL) |
| goto out; |
| |
| if (file_type(name, NULL, NULL) == OS_TYPE_SYMLINK) { |
| name = follow_link(name); |
| if (IS_ERR(name)) { |
| err = PTR_ERR(name); |
| goto out; |
| } |
| } |
| |
| err = read_name(ino, name); |
| kfree(name); |
| out: |
| return err; |
| } |
| |
| static struct inode *hostfs_iget(struct super_block *sb) |
| { |
| struct inode *inode; |
| long ret; |
| |
| inode = iget_locked(sb, 0); |
| if (!inode) |
| return ERR_PTR(-ENOMEM); |
| if (inode->i_state & I_NEW) { |
| ret = hostfs_read_inode(inode); |
| if (ret < 0) { |
| iget_failed(inode); |
| return ERR_PTR(ret); |
| } |
| unlock_new_inode(inode); |
| } |
| return inode; |
| } |
| |
| int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) |
| { |
| /* |
| * do_statfs uses struct statfs64 internally, but the linux kernel |
| * struct statfs still has 32-bit versions for most of these fields, |
| * so we convert them here |
| */ |
| int err; |
| long long f_blocks; |
| long long f_bfree; |
| long long f_bavail; |
| long long f_files; |
| long long f_ffree; |
| |
| err = do_statfs(HOSTFS_I(dentry->d_sb->s_root->d_inode)->host_filename, |
| &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, |
| &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), |
| &sf->f_namelen, sf->f_spare); |
| if (err) |
| return err; |
| sf->f_blocks = f_blocks; |
| sf->f_bfree = f_bfree; |
| sf->f_bavail = f_bavail; |
| sf->f_files = f_files; |
| sf->f_ffree = f_ffree; |
| sf->f_type = HOSTFS_SUPER_MAGIC; |
| return 0; |
| } |
| |
| static struct inode *hostfs_alloc_inode(struct super_block *sb) |
| { |
| struct hostfs_inode_info *hi; |
| |
| hi = kmalloc(sizeof(*hi), GFP_KERNEL); |
| if (hi == NULL) |
| return NULL; |
| |
| *hi = ((struct hostfs_inode_info) { .host_filename = NULL, |
| .fd = -1, |
| .mode = 0 }); |
| inode_init_once(&hi->vfs_inode); |
| return &hi->vfs_inode; |
| } |
| |
| static void hostfs_delete_inode(struct inode *inode) |
| { |
| truncate_inode_pages(&inode->i_data, 0); |
| if (HOSTFS_I(inode)->fd != -1) { |
| close_file(&HOSTFS_I(inode)->fd); |
| HOSTFS_I(inode)->fd = -1; |
| } |
| clear_inode(inode); |
| } |
| |
| static void hostfs_destroy_inode(struct inode *inode) |
| { |
| kfree(HOSTFS_I(inode)->host_filename); |
| |
| /* |
| * XXX: This should not happen, probably. The check is here for |
| * additional safety. |
| */ |
| if (HOSTFS_I(inode)->fd != -1) { |
| close_file(&HOSTFS_I(inode)->fd); |
| printk(KERN_DEBUG "Closing host fd in .destroy_inode\n"); |
| } |
| |
| kfree(HOSTFS_I(inode)); |
| } |
| |
| static int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs) |
| { |
| struct inode *root = vfs->mnt_sb->s_root->d_inode; |
| const char *root_path = HOSTFS_I(root)->host_filename; |
| size_t offset = strlen(root_ino) + 1; |
| |
| if (strlen(root_path) > offset) |
| seq_printf(seq, ",%s", root_path + offset); |
| |
| return 0; |
| } |
| |
| static const struct super_operations hostfs_sbops = { |
| .alloc_inode = hostfs_alloc_inode, |
| .drop_inode = generic_delete_inode, |
| .delete_inode = hostfs_delete_inode, |
| .destroy_inode = hostfs_destroy_inode, |
| .statfs = hostfs_statfs, |
| .show_options = hostfs_show_options, |
| }; |
| |
| int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) |
| { |
| void *dir; |
| char *name; |
| unsigned long long next, ino; |
| int error, len; |
| |
| name = dentry_name(file->f_path.dentry, 0); |
| if (name == NULL) |
| return -ENOMEM; |
| dir = open_dir(name, &error); |
| kfree(name); |
| if (dir == NULL) |
| return -error; |
| next = file->f_pos; |
| while ((name = read_dir(dir, &next, &ino, &len)) != NULL) { |
| error = (*filldir)(ent, name, len, file->f_pos, |
| ino, DT_UNKNOWN); |
| if (error) break; |
| file->f_pos = next; |
| } |
| close_dir(dir); |
| return 0; |
| } |
| |
| int hostfs_file_open(struct inode *ino, struct file *file) |
| { |
| char *name; |
| fmode_t mode = 0; |
| int r = 0, w = 0, fd; |
| |
| mode = file->f_mode & (FMODE_READ | FMODE_WRITE); |
| if ((mode & HOSTFS_I(ino)->mode) == mode) |
| return 0; |
| |
| /* |
| * The file may already have been opened, but with the wrong access, |
| * so this resets things and reopens the file with the new access. |
| */ |
| if (HOSTFS_I(ino)->fd != -1) { |
| close_file(&HOSTFS_I(ino)->fd); |
| HOSTFS_I(ino)->fd = -1; |
| } |
| |
| HOSTFS_I(ino)->mode |= mode; |
| if (HOSTFS_I(ino)->mode & FMODE_READ) |
| r = 1; |
| if (HOSTFS_I(ino)->mode & FMODE_WRITE) |
| w = 1; |
| if (w) |
| r = 1; |
| |
| name = dentry_name(file->f_path.dentry, 0); |
| if (name == NULL) |
| return -ENOMEM; |
| |
| fd = open_file(name, r, w, append); |
| kfree(name); |
| if (fd < 0) |
| return fd; |
| FILE_HOSTFS_I(file)->fd = fd; |
| |
| return 0; |
| } |
| |
| int hostfs_fsync(struct file *file, int datasync) |
| { |
| return fsync_file(HOSTFS_I(file->f_mapping->host)->fd, datasync); |
| } |
| |
| static const struct file_operations hostfs_file_fops = { |
| .llseek = generic_file_llseek, |
| .read = do_sync_read, |
| .splice_read = generic_file_splice_read, |
| .aio_read = generic_file_aio_read, |
| .aio_write = generic_file_aio_write, |
| .write = do_sync_write, |
| .mmap = generic_file_mmap, |
| .open = hostfs_file_open, |
| .release = NULL, |
| .fsync = hostfs_fsync, |
| }; |
| |
| static const struct file_operations hostfs_dir_fops = { |
| .llseek = generic_file_llseek, |
| .readdir = hostfs_readdir, |
| .read = generic_read_dir, |
| }; |
| |
| int hostfs_writepage(struct page *page, struct writeback_control *wbc) |
| { |
| struct address_space *mapping = page->mapping; |
| struct inode *inode = mapping->host; |
| char *buffer; |
| unsigned long long base; |
| int count = PAGE_CACHE_SIZE; |
| int end_index = inode->i_size >> PAGE_CACHE_SHIFT; |
| int err; |
| |
| if (page->index >= end_index) |
| count = inode->i_size & (PAGE_CACHE_SIZE-1); |
| |
| buffer = kmap(page); |
| base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; |
| |
| err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); |
| if (err != count) { |
| ClearPageUptodate(page); |
| goto out; |
| } |
| |
| if (base > inode->i_size) |
| inode->i_size = base; |
| |
| if (PageError(page)) |
| ClearPageError(page); |
| err = 0; |
| |
| out: |
| kunmap(page); |
| |
| unlock_page(page); |
| return err; |
| } |
| |
| int hostfs_readpage(struct file *file, struct page *page) |
| { |
| char *buffer; |
| long long start; |
| int err = 0; |
| |
| start = (long long) page->index << PAGE_CACHE_SHIFT; |
| buffer = kmap(page); |
| err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, |
| PAGE_CACHE_SIZE); |
| if (err < 0) |
| goto out; |
| |
| memset(&buffer[err], 0, PAGE_CACHE_SIZE - err); |
| |
| flush_dcache_page(page); |
| SetPageUptodate(page); |
| if (PageError(page)) ClearPageError(page); |
| err = 0; |
| out: |
| kunmap(page); |
| unlock_page(page); |
| return err; |
| } |
| |
| int hostfs_write_begin(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned flags, |
| struct page **pagep, void **fsdata) |
| { |
| pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
| |
| *pagep = grab_cache_page_write_begin(mapping, index, flags); |
| if (!*pagep) |
| return -ENOMEM; |
| return 0; |
| } |
| |
| int hostfs_write_end(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned copied, |
| struct page *page, void *fsdata) |
| { |
| struct inode *inode = mapping->host; |
| void *buffer; |
| unsigned from = pos & (PAGE_CACHE_SIZE - 1); |
| int err; |
| |
| buffer = kmap(page); |
| err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); |
| kunmap(page); |
| |
| if (!PageUptodate(page) && err == PAGE_CACHE_SIZE) |
| SetPageUptodate(page); |
| |
| /* |
| * If err > 0, write_file has added err to pos, so we are comparing |
| * i_size against the last byte written. |
| */ |
| if (err > 0 && (pos > inode->i_size)) |
| inode->i_size = pos; |
| unlock_page(page); |
| page_cache_release(page); |
| |
| return err; |
| } |
| |
| static const struct address_space_operations hostfs_aops = { |
| .writepage = hostfs_writepage, |
| .readpage = hostfs_readpage, |
| .set_page_dirty = __set_page_dirty_nobuffers, |
| .write_begin = hostfs_write_begin, |
| .write_end = hostfs_write_end, |
| }; |
| |
| static int init_inode(struct inode *inode, struct dentry *dentry) |
| { |
| char *name; |
| int type, err = -ENOMEM; |
| int maj, min; |
| dev_t rdev = 0; |
| |
| if (dentry) { |
| name = dentry_name(dentry, 0); |
| if (name == NULL) |
| goto out; |
| type = file_type(name, &maj, &min); |
| /* Reencode maj and min with the kernel encoding.*/ |
| rdev = MKDEV(maj, min); |
| kfree(name); |
| } |
| else type = OS_TYPE_DIR; |
| |
| err = 0; |
| if (type == OS_TYPE_SYMLINK) |
| inode->i_op = &page_symlink_inode_operations; |
| else if (type == OS_TYPE_DIR) |
| inode->i_op = &hostfs_dir_iops; |
| else inode->i_op = &hostfs_iops; |
| |
| if (type == OS_TYPE_DIR) inode->i_fop = &hostfs_dir_fops; |
| else inode->i_fop = &hostfs_file_fops; |
| |
| if (type == OS_TYPE_SYMLINK) |
| inode->i_mapping->a_ops = &hostfs_link_aops; |
| else inode->i_mapping->a_ops = &hostfs_aops; |
| |
| switch (type) { |
| case OS_TYPE_CHARDEV: |
| init_special_inode(inode, S_IFCHR, rdev); |
| break; |
| case OS_TYPE_BLOCKDEV: |
| init_special_inode(inode, S_IFBLK, rdev); |
| break; |
| case OS_TYPE_FIFO: |
| init_special_inode(inode, S_IFIFO, 0); |
| break; |
| case OS_TYPE_SOCK: |
| init_special_inode(inode, S_IFSOCK, 0); |
| break; |
| } |
| out: |
| return err; |
| } |
| |
| int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, |
| struct nameidata *nd) |
| { |
| struct inode *inode; |
| char *name; |
| int error, fd; |
| |
| inode = hostfs_iget(dir->i_sb); |
| if (IS_ERR(inode)) { |
| error = PTR_ERR(inode); |
| goto out; |
| } |
| |
| error = init_inode(inode, dentry); |
| if (error) |
| goto out_put; |
| |
| error = -ENOMEM; |
| name = dentry_name(dentry, 0); |
| if (name == NULL) |
| goto out_put; |
| |
| fd = file_create(name, |
| mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, |
| mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, |
| mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); |
| if (fd < 0) |
| error = fd; |
| else error = read_name(inode, name); |
| |
| kfree(name); |
| if (error) |
| goto out_put; |
| |
| HOSTFS_I(inode)->fd = fd; |
| HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; |
| d_instantiate(dentry, inode); |
| return 0; |
| |
| out_put: |
| iput(inode); |
| out: |
| return error; |
| } |
| |
| struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, |
| struct nameidata *nd) |
| { |
| struct inode *inode; |
| char *name; |
| int err; |
| |
| inode = hostfs_iget(ino->i_sb); |
| if (IS_ERR(inode)) { |
| err = PTR_ERR(inode); |
| goto out; |
| } |
| |
| err = init_inode(inode, dentry); |
| if (err) |
| goto out_put; |
| |
| err = -ENOMEM; |
| name = dentry_name(dentry, 0); |
| if (name == NULL) |
| goto out_put; |
| |
| err = read_name(inode, name); |
| kfree(name); |
| if (err == -ENOENT) { |
| iput(inode); |
| inode = NULL; |
| } |
| else if (err) |
| goto out_put; |
| |
| d_add(dentry, inode); |
| dentry->d_op = &hostfs_dentry_ops; |
| return NULL; |
| |
| out_put: |
| iput(inode); |
| out: |
| return ERR_PTR(err); |
| } |
| |
| static char *inode_dentry_name(struct inode *ino, struct dentry *dentry) |
| { |
| char *file; |
| int len; |
| |
| file = inode_name(ino, dentry->d_name.len + 1); |
| if (file == NULL) |
| return NULL; |
| strcat(file, "/"); |
| len = strlen(file); |
| strncat(file, dentry->d_name.name, dentry->d_name.len); |
| file[len + dentry->d_name.len] = '\0'; |
| return file; |
| } |
| |
| int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from) |
| { |
| char *from_name, *to_name; |
| int err; |
| |
| if ((from_name = inode_dentry_name(ino, from)) == NULL) |
| return -ENOMEM; |
| to_name = dentry_name(to, 0); |
| if (to_name == NULL) { |
| kfree(from_name); |
| return -ENOMEM; |
| } |
| err = link_file(to_name, from_name); |
| kfree(from_name); |
| kfree(to_name); |
| return err; |
| } |
| |
| int hostfs_unlink(struct inode *ino, struct dentry *dentry) |
| { |
| char *file; |
| int err; |
| |
| if ((file = inode_dentry_name(ino, dentry)) == NULL) |
| return -ENOMEM; |
| if (append) |
| return -EPERM; |
| |
| err = unlink_file(file); |
| kfree(file); |
| return err; |
| } |
| |
| int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to) |
| { |
| char *file; |
| int err; |
| |
| if ((file = inode_dentry_name(ino, dentry)) == NULL) |
| return -ENOMEM; |
| err = make_symlink(file, to); |
| kfree(file); |
| return err; |
| } |
| |
| int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode) |
| { |
| char *file; |
| int err; |
| |
| if ((file = inode_dentry_name(ino, dentry)) == NULL) |
| return -ENOMEM; |
| err = do_mkdir(file, mode); |
| kfree(file); |
| return err; |
| } |
| |
| int hostfs_rmdir(struct inode *ino, struct dentry *dentry) |
| { |
| char *file; |
| int err; |
| |
| if ((file = inode_dentry_name(ino, dentry)) == NULL) |
| return -ENOMEM; |
| err = do_rmdir(file); |
| kfree(file); |
| return err; |
| } |
| |
| int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) |
| { |
| struct inode *inode; |
| char *name; |
| int err; |
| |
| inode = hostfs_iget(dir->i_sb); |
| if (IS_ERR(inode)) { |
| err = PTR_ERR(inode); |
| goto out; |
| } |
| |
| err = init_inode(inode, dentry); |
| if (err) |
| goto out_put; |
| |
| err = -ENOMEM; |
| name = dentry_name(dentry, 0); |
| if (name == NULL) |
| goto out_put; |
| |
| init_special_inode(inode, mode, dev); |
| err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); |
| if (err) |
| goto out_free; |
| |
| err = read_name(inode, name); |
| kfree(name); |
| if (err) |
| goto out_put; |
| |
| d_instantiate(dentry, inode); |
| return 0; |
| |
| out_free: |
| kfree(name); |
| out_put: |
| iput(inode); |
| out: |
| return err; |
| } |
| |
| int hostfs_rename(struct inode *from_ino, struct dentry *from, |
| struct inode *to_ino, struct dentry *to) |
| { |
| char *from_name, *to_name; |
| int err; |
| |
| if ((from_name = inode_dentry_name(from_ino, from)) == NULL) |
| return -ENOMEM; |
| if ((to_name = inode_dentry_name(to_ino, to)) == NULL) { |
| kfree(from_name); |
| return -ENOMEM; |
| } |
| err = rename_file(from_name, to_name); |
| kfree(from_name); |
| kfree(to_name); |
| return err; |
| } |
| |
| int hostfs_permission(struct inode *ino, int desired) |
| { |
| char *name; |
| int r = 0, w = 0, x = 0, err; |
| |
| if (desired & MAY_READ) r = 1; |
| if (desired & MAY_WRITE) w = 1; |
| if (desired & MAY_EXEC) x = 1; |
| name = inode_name(ino, 0); |
| if (name == NULL) |
| return -ENOMEM; |
| |
| if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || |
| S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) |
| err = 0; |
| else |
| err = access_file(name, r, w, x); |
| kfree(name); |
| if (!err) |
| err = generic_permission(ino, desired, NULL); |
| return err; |
| } |
| |
| int hostfs_setattr(struct dentry *dentry, struct iattr *attr) |
| { |
| struct inode *inode = dentry->d_inode; |
| struct hostfs_iattr attrs; |
| char *name; |
| int err; |
| |
| int fd = HOSTFS_I(inode)->fd; |
| |
| err = inode_change_ok(inode, attr); |
| if (err) |
| return err; |
| |
| if (append) |
| attr->ia_valid &= ~ATTR_SIZE; |
| |
| attrs.ia_valid = 0; |
| if (attr->ia_valid & ATTR_MODE) { |
| attrs.ia_valid |= HOSTFS_ATTR_MODE; |
| attrs.ia_mode = attr->ia_mode; |
| } |
| if (attr->ia_valid & ATTR_UID) { |
| attrs.ia_valid |= HOSTFS_ATTR_UID; |
| attrs.ia_uid = attr->ia_uid; |
| } |
| if (attr->ia_valid & ATTR_GID) { |
| attrs.ia_valid |= HOSTFS_ATTR_GID; |
| attrs.ia_gid = attr->ia_gid; |
| } |
| if (attr->ia_valid & ATTR_SIZE) { |
| attrs.ia_valid |= HOSTFS_ATTR_SIZE; |
| attrs.ia_size = attr->ia_size; |
| } |
| if (attr->ia_valid & ATTR_ATIME) { |
| attrs.ia_valid |= HOSTFS_ATTR_ATIME; |
| attrs.ia_atime = attr->ia_atime; |
| } |
| if (attr->ia_valid & ATTR_MTIME) { |
| attrs.ia_valid |= HOSTFS_ATTR_MTIME; |
| attrs.ia_mtime = attr->ia_mtime; |
| } |
| if (attr->ia_valid & ATTR_CTIME) { |
| attrs.ia_valid |= HOSTFS_ATTR_CTIME; |
| attrs.ia_ctime = attr->ia_ctime; |
| } |
| if (attr->ia_valid & ATTR_ATIME_SET) { |
| attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; |
| } |
| if (attr->ia_valid & ATTR_MTIME_SET) { |
| attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; |
| } |
| name = dentry_name(dentry, 0); |
| if (name == NULL) |
| return -ENOMEM; |
| err = set_attr(name, &attrs, fd); |
| kfree(name); |
| if (err) |
| return err; |
| |
| if ((attr->ia_valid & ATTR_SIZE) && |
| attr->ia_size != i_size_read(inode)) { |
| int error; |
| |
| error = vmtruncate(inode, attr->ia_size); |
| if (err) |
| return err; |
| } |
| |
| setattr_copy(inode, attr); |
| mark_inode_dirty(inode); |
| return 0; |
| } |
| |
| static const struct inode_operations hostfs_iops = { |
| .create = hostfs_create, |
| .link = hostfs_link, |
| .unlink = hostfs_unlink, |
| .symlink = hostfs_symlink, |
| .mkdir = hostfs_mkdir, |
| .rmdir = hostfs_rmdir, |
| .mknod = hostfs_mknod, |
| .rename = hostfs_rename, |
| .permission = hostfs_permission, |
| .setattr = hostfs_setattr, |
| }; |
| |
| static const struct inode_operations hostfs_dir_iops = { |
| .create = hostfs_create, |
| .lookup = hostfs_lookup, |
| .link = hostfs_link, |
| .unlink = hostfs_unlink, |
| .symlink = hostfs_symlink, |
| .mkdir = hostfs_mkdir, |
| .rmdir = hostfs_rmdir, |
| .mknod = hostfs_mknod, |
| .rename = hostfs_rename, |
| .permission = hostfs_permission, |
| .setattr = hostfs_setattr, |
| }; |
| |
| int hostfs_link_readpage(struct file *file, struct page *page) |
| { |
| char *buffer, *name; |
| int err; |
| |
| buffer = kmap(page); |
| name = inode_name(page->mapping->host, 0); |
| if (name == NULL) |
| return -ENOMEM; |
| err = hostfs_do_readlink(name, buffer, PAGE_CACHE_SIZE); |
| kfree(name); |
| if (err == PAGE_CACHE_SIZE) |
| err = -E2BIG; |
| else if (err > 0) { |
| flush_dcache_page(page); |
| SetPageUptodate(page); |
| if (PageError(page)) ClearPageError(page); |
| err = 0; |
| } |
| kunmap(page); |
| unlock_page(page); |
| return err; |
| } |
| |
| static const struct address_space_operations hostfs_link_aops = { |
| .readpage = hostfs_link_readpage, |
| }; |
| |
| static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) |
| { |
| struct inode *root_inode; |
| char *host_root_path, *req_root = d; |
| int err; |
| |
| sb->s_blocksize = 1024; |
| sb->s_blocksize_bits = 10; |
| sb->s_magic = HOSTFS_SUPER_MAGIC; |
| sb->s_op = &hostfs_sbops; |
| sb->s_maxbytes = MAX_LFS_FILESIZE; |
| |
| /* NULL is printed as <NULL> by sprintf: avoid that. */ |
| if (req_root == NULL) |
| req_root = ""; |
| |
| err = -ENOMEM; |
| host_root_path = kmalloc(strlen(root_ino) + 1 |
| + strlen(req_root) + 1, GFP_KERNEL); |
| if (host_root_path == NULL) |
| goto out; |
| |
| sprintf(host_root_path, "%s/%s", root_ino, req_root); |
| |
| root_inode = hostfs_iget(sb); |
| if (IS_ERR(root_inode)) { |
| err = PTR_ERR(root_inode); |
| goto out_free; |
| } |
| |
| err = init_inode(root_inode, NULL); |
| if (err) |
| goto out_put; |
| |
| HOSTFS_I(root_inode)->host_filename = host_root_path; |
| /* |
| * Avoid that in the error path, iput(root_inode) frees again |
| * host_root_path through hostfs_destroy_inode! |
| */ |
| host_root_path = NULL; |
| |
| err = -ENOMEM; |
| sb->s_root = d_alloc_root(root_inode); |
| if (sb->s_root == NULL) |
| goto out_put; |
| |
| err = hostfs_read_inode(root_inode); |
| if (err) { |
| /* No iput in this case because the dput does that for us */ |
| dput(sb->s_root); |
| sb->s_root = NULL; |
| goto out; |
| } |
| |
| return 0; |
| |
| out_put: |
| iput(root_inode); |
| out_free: |
| kfree(host_root_path); |
| out: |
| return err; |
| } |
| |
| static int hostfs_read_sb(struct file_system_type *type, |
| int flags, const char *dev_name, |
| void *data, struct vfsmount *mnt) |
| { |
| return get_sb_nodev(type, flags, data, hostfs_fill_sb_common, mnt); |
| } |
| |
| static struct file_system_type hostfs_type = { |
| .owner = THIS_MODULE, |
| .name = "hostfs", |
| .get_sb = hostfs_read_sb, |
| .kill_sb = kill_anon_super, |
| .fs_flags = 0, |
| }; |
| |
| static int __init init_hostfs(void) |
| { |
| return register_filesystem(&hostfs_type); |
| } |
| |
| static void __exit exit_hostfs(void) |
| { |
| unregister_filesystem(&hostfs_type); |
| } |
| |
| module_init(init_hostfs) |
| module_exit(exit_hostfs) |
| MODULE_LICENSE("GPL"); |