2 * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
3 * Licensed under the GPL
5 * Ported the filesystem routines to 2.5.
6 * 2003-02-10 Petr Baudis <pasky@ucw.cz>
9 #include <linux/stddef.h>
11 #include <linux/version.h>
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/slab.h>
15 #include <linux/pagemap.h>
16 #include <linux/blkdev.h>
17 #include <linux/list.h>
18 #include <linux/buffer_head.h>
19 #include <linux/root_dev.h>
20 #include <linux/statfs.h>
21 #include <linux/kdev_t.h>
22 #include <asm/uaccess.h>
24 #include "kern_util.h"
26 #include "user_util.h"
27 #include "2_5compat.h"
30 struct hostfs_inode_info {
34 struct inode vfs_inode;
37 static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode)
39 return(list_entry(inode, struct hostfs_inode_info, vfs_inode));
42 #define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_dentry->d_inode)
44 int hostfs_d_delete(struct dentry *dentry)
49 struct dentry_operations hostfs_dentry_ops = {
50 .d_delete = hostfs_d_delete,
53 /* Changed in hostfs_args before the kernel starts running */
54 static char *root_ino = "/";
55 static int append = 0;
57 #define HOSTFS_SUPER_MAGIC 0x00c0ffee
59 static struct inode_operations hostfs_iops;
60 static struct inode_operations hostfs_dir_iops;
61 static struct address_space_operations hostfs_link_aops;
64 static int __init hostfs_args(char *options, int *add)
68 ptr = strchr(options, ',');
76 ptr = strchr(options, ',');
80 if(!strcmp(options, "append"))
82 else printf("hostfs_args - unsupported option - %s\n",
90 __uml_setup("hostfs=", hostfs_args,
91 "hostfs=<root dir>,<flags>,...\n"
92 " This is used to set hostfs parameters. The root directory argument\n"
93 " is used to confine all hostfs mounts to within the specified directory\n"
94 " tree on the host. If this isn't specified, then a user inside UML can\n"
95 " mount anything on the host that's accessible to the user that's running\n"
97 " The only flag currently supported is 'append', which specifies that all\n"
98 " files opened by hostfs will be opened in append mode.\n\n"
102 static char *dentry_name(struct dentry *dentry, int extra)
104 struct dentry *parent;
110 while(parent->d_parent != parent){
111 len += parent->d_name.len + 1;
112 parent = parent->d_parent;
115 root = HOSTFS_I(parent->d_inode)->host_filename;
117 name = kmalloc(len + extra + 1, GFP_KERNEL);
118 if(name == NULL) return(NULL);
122 while(parent->d_parent != parent){
123 len -= parent->d_name.len + 1;
125 strncpy(&name[len + 1], parent->d_name.name,
127 parent = parent->d_parent;
129 strncpy(name, root, strlen(root));
133 static char *inode_name(struct inode *ino, int extra)
135 struct dentry *dentry;
137 dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias);
138 return(dentry_name(dentry, extra));
141 static int read_name(struct inode *ino, char *name)
143 /* The non-int inode fields are copied into ints by stat_file and
144 * then copied into the inode because passing the actual pointers
145 * in and having them treated as int * breaks on big-endian machines
148 int i_mode, i_nlink, i_blksize;
149 unsigned long long i_size;
150 unsigned long long i_ino;
151 unsigned long long i_blocks;
153 err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid,
154 &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime,
155 &ino->i_ctime, &i_blksize, &i_blocks);
160 ino->i_mode = i_mode;
161 ino->i_nlink = i_nlink;
162 ino->i_size = i_size;
163 ino->i_blksize = i_blksize;
164 ino->i_blocks = i_blocks;
165 if((ino->i_sb->s_dev == ROOT_DEV) && (ino->i_uid == getuid()))
170 static char *follow_link(char *link)
173 char *name, *resolved, *end;
178 name = kmalloc(len, GFP_KERNEL);
182 n = do_readlink(link, name, len);
194 end = strrchr(link, '/');
199 len = strlen(link) + strlen(name) + 1;
201 resolved = kmalloc(len, GFP_KERNEL);
202 if(resolved == NULL){
207 sprintf(resolved, "%s%s", link, name);
218 static int read_inode(struct inode *ino)
223 /* Unfortunately, we are called from iget() when we don't have a dentry
226 if(list_empty(&ino->i_dentry))
230 name = inode_name(ino, 0);
234 if(file_type(name, NULL, NULL) == OS_TYPE_SYMLINK){
235 name = follow_link(name);
242 err = read_name(ino, name);
248 int hostfs_statfs(struct super_block *sb, struct kstatfs *sf)
250 /* do_statfs uses struct statfs64 internally, but the linux kernel
251 * struct statfs still has 32-bit versions for most of these fields,
252 * so we convert them here
261 err = do_statfs(HOSTFS_I(sb->s_root->d_inode)->host_filename,
262 &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files,
263 &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid),
264 &sf->f_namelen, sf->f_spare);
266 sf->f_blocks = f_blocks;
267 sf->f_bfree = f_bfree;
268 sf->f_bavail = f_bavail;
269 sf->f_files = f_files;
270 sf->f_ffree = f_ffree;
271 sf->f_type = HOSTFS_SUPER_MAGIC;
275 static struct inode *hostfs_alloc_inode(struct super_block *sb)
277 struct hostfs_inode_info *hi;
279 hi = kmalloc(sizeof(*hi), GFP_KERNEL);
283 *hi = ((struct hostfs_inode_info) { .host_filename = NULL,
286 inode_init_once(&hi->vfs_inode);
287 return(&hi->vfs_inode);
290 static void hostfs_delete_inode(struct inode *inode)
292 if(HOSTFS_I(inode)->fd != -1) {
293 close_file(&HOSTFS_I(inode)->fd);
294 HOSTFS_I(inode)->fd = -1;
299 static void hostfs_destroy_inode(struct inode *inode)
301 if(HOSTFS_I(inode)->host_filename)
302 kfree(HOSTFS_I(inode)->host_filename);
304 /*XXX: This should not happen, probably. The check is here for
305 * additional safety.*/
306 if(HOSTFS_I(inode)->fd != -1) {
307 close_file(&HOSTFS_I(inode)->fd);
308 printk(KERN_DEBUG "Closing host fd in .destroy_inode\n");
311 kfree(HOSTFS_I(inode));
314 static void hostfs_read_inode(struct inode *inode)
319 static struct super_operations hostfs_sbops = {
320 .alloc_inode = hostfs_alloc_inode,
321 .drop_inode = generic_delete_inode,
322 .delete_inode = hostfs_delete_inode,
323 .destroy_inode = hostfs_destroy_inode,
324 .read_inode = hostfs_read_inode,
325 .statfs = hostfs_statfs,
328 int hostfs_readdir(struct file *file, void *ent, filldir_t filldir)
332 unsigned long long next, ino;
335 name = dentry_name(file->f_dentry, 0);
336 if(name == NULL) return(-ENOMEM);
337 dir = open_dir(name, &error);
339 if(dir == NULL) return(-error);
341 while((name = read_dir(dir, &next, &ino, &len)) != NULL){
342 error = (*filldir)(ent, name, len, file->f_pos,
351 int hostfs_file_open(struct inode *ino, struct file *file)
354 int mode = 0, r = 0, w = 0, fd;
356 mode = file->f_mode & (FMODE_READ | FMODE_WRITE);
357 if((mode & HOSTFS_I(ino)->mode) == mode)
360 /* The file may already have been opened, but with the wrong access,
361 * so this resets things and reopens the file with the new access.
363 if(HOSTFS_I(ino)->fd != -1){
364 close_file(&HOSTFS_I(ino)->fd);
365 HOSTFS_I(ino)->fd = -1;
368 HOSTFS_I(ino)->mode |= mode;
369 if(HOSTFS_I(ino)->mode & FMODE_READ)
371 if(HOSTFS_I(ino)->mode & FMODE_WRITE)
376 name = dentry_name(file->f_dentry, 0);
380 fd = open_file(name, r, w, append);
382 if(fd < 0) return(fd);
383 FILE_HOSTFS_I(file)->fd = fd;
388 int hostfs_fsync(struct file *file, struct dentry *dentry, int datasync)
393 static struct file_operations hostfs_file_fops = {
394 .llseek = generic_file_llseek,
395 .read = generic_file_read,
396 .write = generic_file_write,
397 .mmap = generic_file_mmap,
398 .open = hostfs_file_open,
400 .fsync = hostfs_fsync,
403 static struct file_operations hostfs_dir_fops = {
404 .readdir = hostfs_readdir,
405 .read = generic_read_dir,
408 int hostfs_writepage(struct page *page, struct writeback_control *wbc)
410 struct address_space *mapping = page->mapping;
411 struct inode *inode = mapping->host;
413 unsigned long long base;
414 int count = PAGE_CACHE_SIZE;
415 int end_index = inode->i_size >> PAGE_CACHE_SHIFT;
418 if (page->index >= end_index)
419 count = inode->i_size & (PAGE_CACHE_SIZE-1);
422 base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT;
424 err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count);
426 ClearPageUptodate(page);
430 if (base > inode->i_size)
431 inode->i_size = base;
434 ClearPageError(page);
444 int hostfs_readpage(struct file *file, struct page *page)
450 start = (long long) page->index << PAGE_CACHE_SHIFT;
452 err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer,
454 if(err < 0) goto out;
456 memset(&buffer[err], 0, PAGE_CACHE_SIZE - err);
458 flush_dcache_page(page);
459 SetPageUptodate(page);
460 if (PageError(page)) ClearPageError(page);
468 int hostfs_prepare_write(struct file *file, struct page *page,
469 unsigned int from, unsigned int to)
472 long long start, tmp;
475 start = (long long) page->index << PAGE_CACHE_SHIFT;
479 err = read_file(FILE_HOSTFS_I(file)->fd, &tmp, buffer,
481 if(err < 0) goto out;
483 if(to != PAGE_CACHE_SIZE){
485 err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer + to,
486 PAGE_CACHE_SIZE - to);
487 if(err < 0) goto out;
495 int hostfs_commit_write(struct file *file, struct page *page, unsigned from,
498 struct address_space *mapping = page->mapping;
499 struct inode *inode = mapping->host;
504 start = (long long) (page->index << PAGE_CACHE_SHIFT) + from;
506 err = write_file(FILE_HOSTFS_I(file)->fd, &start, buffer + from,
509 if(!err && (start > inode->i_size))
510 inode->i_size = start;
516 static struct address_space_operations hostfs_aops = {
517 .writepage = hostfs_writepage,
518 .readpage = hostfs_readpage,
519 /* .set_page_dirty = __set_page_dirty_nobuffers, */
520 .prepare_write = hostfs_prepare_write,
521 .commit_write = hostfs_commit_write
524 static int init_inode(struct inode *inode, struct dentry *dentry)
527 int type, err = -ENOMEM;
532 name = dentry_name(dentry, 0);
535 type = file_type(name, &maj, &min);
536 /*Reencode maj and min with the kernel encoding.*/
537 rdev = MKDEV(maj, min);
540 else type = OS_TYPE_DIR;
543 if(type == OS_TYPE_SYMLINK)
544 inode->i_op = &page_symlink_inode_operations;
545 else if(type == OS_TYPE_DIR)
546 inode->i_op = &hostfs_dir_iops;
547 else inode->i_op = &hostfs_iops;
549 if(type == OS_TYPE_DIR) inode->i_fop = &hostfs_dir_fops;
550 else inode->i_fop = &hostfs_file_fops;
552 if(type == OS_TYPE_SYMLINK)
553 inode->i_mapping->a_ops = &hostfs_link_aops;
554 else inode->i_mapping->a_ops = &hostfs_aops;
557 case OS_TYPE_CHARDEV:
558 init_special_inode(inode, S_IFCHR, rdev);
560 case OS_TYPE_BLOCKDEV:
561 init_special_inode(inode, S_IFBLK, rdev);
564 init_special_inode(inode, S_IFIFO, 0);
567 init_special_inode(inode, S_IFSOCK, 0);
574 int hostfs_create(struct inode *dir, struct dentry *dentry, int mode,
575 struct nameidata *nd)
582 inode = iget(dir->i_sb, 0);
583 if(inode == NULL) goto out;
585 error = init_inode(inode, dentry);
590 name = dentry_name(dentry, 0);
594 fd = file_create(name,
595 mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR,
596 mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP,
597 mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH);
600 else error = read_name(inode, name);
606 HOSTFS_I(inode)->fd = fd;
607 HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE;
608 d_instantiate(dentry, inode);
617 struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry,
618 struct nameidata *nd)
625 inode = iget(ino->i_sb, 0);
629 err = init_inode(inode, dentry);
634 name = dentry_name(dentry, 0);
638 err = read_name(inode, name);
647 d_add(dentry, inode);
648 dentry->d_op = &hostfs_dentry_ops;
654 return(ERR_PTR(err));
657 static char *inode_dentry_name(struct inode *ino, struct dentry *dentry)
662 file = inode_name(ino, dentry->d_name.len + 1);
663 if(file == NULL) return(NULL);
666 strncat(file, dentry->d_name.name, dentry->d_name.len);
667 file[len + dentry->d_name.len] = '\0';
671 int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from)
673 char *from_name, *to_name;
676 if((from_name = inode_dentry_name(ino, from)) == NULL)
678 to_name = dentry_name(to, 0);
683 err = link_file(to_name, from_name);
689 int hostfs_unlink(struct inode *ino, struct dentry *dentry)
694 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
698 err = unlink_file(file);
703 int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to)
708 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
709 err = make_symlink(file, to);
714 int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode)
719 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
720 err = do_mkdir(file, mode);
725 int hostfs_rmdir(struct inode *ino, struct dentry *dentry)
730 if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
731 err = do_rmdir(file);
736 int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
742 inode = iget(dir->i_sb, 0);
746 err = init_inode(inode, dentry);
751 name = dentry_name(dentry, 0);
755 init_special_inode(inode, mode, dev);
756 err = do_mknod(name, mode, dev);
760 err = read_name(inode, name);
765 d_instantiate(dentry, inode);
776 int hostfs_rename(struct inode *from_ino, struct dentry *from,
777 struct inode *to_ino, struct dentry *to)
779 char *from_name, *to_name;
782 if((from_name = inode_dentry_name(from_ino, from)) == NULL)
784 if((to_name = inode_dentry_name(to_ino, to)) == NULL){
788 err = rename_file(from_name, to_name);
794 void hostfs_truncate(struct inode *ino)
799 int hostfs_permission(struct inode *ino, int desired, struct nameidata *nd)
802 int r = 0, w = 0, x = 0, err;
804 if(desired & MAY_READ) r = 1;
805 if(desired & MAY_WRITE) w = 1;
806 if(desired & MAY_EXEC) x = 1;
807 name = inode_name(ino, 0);
808 if(name == NULL) return(-ENOMEM);
809 err = access_file(name, r, w, x);
811 if(!err) err = vfs_permission(ino, desired);
815 int hostfs_setattr(struct dentry *dentry, struct iattr *attr)
817 struct hostfs_iattr attrs;
822 attr->ia_valid &= ~ATTR_SIZE;
825 if(attr->ia_valid & ATTR_MODE){
826 attrs.ia_valid |= HOSTFS_ATTR_MODE;
827 attrs.ia_mode = attr->ia_mode;
829 if(attr->ia_valid & ATTR_UID){
830 if((dentry->d_inode->i_sb->s_dev == ROOT_DEV) &&
832 attr->ia_uid = getuid();
833 attrs.ia_valid |= HOSTFS_ATTR_UID;
834 attrs.ia_uid = attr->ia_uid;
836 if(attr->ia_valid & ATTR_GID){
837 if((dentry->d_inode->i_sb->s_dev == ROOT_DEV) &&
839 attr->ia_gid = getuid();
840 attrs.ia_valid |= HOSTFS_ATTR_GID;
841 attrs.ia_gid = attr->ia_gid;
843 if(attr->ia_valid & ATTR_SIZE){
844 attrs.ia_valid |= HOSTFS_ATTR_SIZE;
845 attrs.ia_size = attr->ia_size;
847 if(attr->ia_valid & ATTR_ATIME){
848 attrs.ia_valid |= HOSTFS_ATTR_ATIME;
849 attrs.ia_atime = attr->ia_atime;
851 if(attr->ia_valid & ATTR_MTIME){
852 attrs.ia_valid |= HOSTFS_ATTR_MTIME;
853 attrs.ia_mtime = attr->ia_mtime;
855 if(attr->ia_valid & ATTR_CTIME){
856 attrs.ia_valid |= HOSTFS_ATTR_CTIME;
857 attrs.ia_ctime = attr->ia_ctime;
859 if(attr->ia_valid & ATTR_ATIME_SET){
860 attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET;
862 if(attr->ia_valid & ATTR_MTIME_SET){
863 attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET;
865 name = dentry_name(dentry, 0);
866 if(name == NULL) return(-ENOMEM);
867 err = set_attr(name, &attrs);
872 return(inode_setattr(dentry->d_inode, attr));
875 int hostfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
878 generic_fillattr(dentry->d_inode, stat);
882 static struct inode_operations hostfs_iops = {
883 .create = hostfs_create,
885 .unlink = hostfs_unlink,
886 .symlink = hostfs_symlink,
887 .mkdir = hostfs_mkdir,
888 .rmdir = hostfs_rmdir,
889 .mknod = hostfs_mknod,
890 .rename = hostfs_rename,
891 .truncate = hostfs_truncate,
892 .permission = hostfs_permission,
893 .setattr = hostfs_setattr,
894 .getattr = hostfs_getattr,
897 static struct inode_operations hostfs_dir_iops = {
898 .create = hostfs_create,
899 .lookup = hostfs_lookup,
901 .unlink = hostfs_unlink,
902 .symlink = hostfs_symlink,
903 .mkdir = hostfs_mkdir,
904 .rmdir = hostfs_rmdir,
905 .mknod = hostfs_mknod,
906 .rename = hostfs_rename,
907 .truncate = hostfs_truncate,
908 .permission = hostfs_permission,
909 .setattr = hostfs_setattr,
910 .getattr = hostfs_getattr,
913 int hostfs_link_readpage(struct file *file, struct page *page)
919 start = page->index << PAGE_CACHE_SHIFT;
921 name = inode_name(page->mapping->host, 0);
922 if(name == NULL) return(-ENOMEM);
923 err = do_readlink(name, buffer, PAGE_CACHE_SIZE);
925 if(err == PAGE_CACHE_SIZE)
928 flush_dcache_page(page);
929 SetPageUptodate(page);
930 if (PageError(page)) ClearPageError(page);
938 static struct address_space_operations hostfs_link_aops = {
939 .readpage = hostfs_link_readpage,
942 static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
944 struct inode *root_inode;
945 char *name, *data = d;
948 sb->s_blocksize = 1024;
949 sb->s_blocksize_bits = 10;
950 sb->s_magic = HOSTFS_SUPER_MAGIC;
951 sb->s_op = &hostfs_sbops;
953 if((data == NULL) || (*data == '\0'))
957 name = kmalloc(strlen(data) + 1, GFP_KERNEL);
963 root_inode = iget(sb, 0);
964 if(root_inode == NULL)
967 err = init_inode(root_inode, NULL);
971 HOSTFS_I(root_inode)->host_filename = name;
974 sb->s_root = d_alloc_root(root_inode);
975 if(sb->s_root == NULL)
978 err = read_inode(root_inode);
992 static struct super_block *hostfs_read_sb(struct file_system_type *type,
993 int flags, const char *dev_name,
996 return(get_sb_nodev(type, flags, data, hostfs_fill_sb_common));
999 static struct file_system_type hostfs_type = {
1000 .owner = THIS_MODULE,
1002 .get_sb = hostfs_read_sb,
1003 .kill_sb = kill_anon_super,
1007 static int __init init_hostfs(void)
1009 return(register_filesystem(&hostfs_type));
1012 static void __exit exit_hostfs(void)
1014 unregister_filesystem(&hostfs_type);
1017 module_init(init_hostfs)
1018 module_exit(exit_hostfs)
1019 MODULE_LICENSE("GPL");
1022 * Overrides for Emacs so that we follow Linus's tabbing style.
1023 * Emacs will notice this stuff at the end of the file and automatically
1024 * adjust the settings for this buffer only. This must remain at the end
1026 * ---------------------------------------------------------------------------
1028 * c-file-style: "linux"