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1014 lines
21 KiB
1014 lines
21 KiB
/* |
|
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
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* Licensed under the GPL |
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* |
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* Ported the filesystem routines to 2.5. |
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* 2003-02-10 Petr Baudis <[email protected]> |
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*/ |
|
|
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#include <linux/fs.h> |
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#include <linux/magic.h> |
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#include <linux/module.h> |
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#include <linux/mm.h> |
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#include <linux/pagemap.h> |
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#include <linux/statfs.h> |
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#include <linux/slab.h> |
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#include <linux/seq_file.h> |
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#include <linux/writeback.h> |
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#include <linux/mount.h> |
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#include <linux/namei.h> |
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#include "hostfs.h" |
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#include <init.h> |
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#include <kern.h> |
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|
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struct hostfs_inode_info { |
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int fd; |
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fmode_t mode; |
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struct inode vfs_inode; |
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struct mutex open_mutex; |
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}; |
|
|
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static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) |
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{ |
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return list_entry(inode, struct hostfs_inode_info, vfs_inode); |
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} |
|
|
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#define FILE_HOSTFS_I(file) HOSTFS_I(file_inode(file)) |
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|
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static struct kmem_cache *hostfs_inode_cache; |
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|
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/* Changed in hostfs_args before the kernel starts running */ |
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static char *root_ino = ""; |
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static int append = 0; |
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|
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static const struct inode_operations hostfs_iops; |
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static const struct inode_operations hostfs_dir_iops; |
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static const struct inode_operations hostfs_link_iops; |
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|
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#ifndef MODULE |
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static int __init hostfs_args(char *options, int *add) |
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{ |
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char *ptr; |
|
|
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ptr = strchr(options, ','); |
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if (ptr != NULL) |
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*ptr++ = '\0'; |
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if (*options != '\0') |
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root_ino = options; |
|
|
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options = ptr; |
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while (options) { |
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ptr = strchr(options, ','); |
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if (ptr != NULL) |
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*ptr++ = '\0'; |
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if (*options != '\0') { |
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if (!strcmp(options, "append")) |
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append = 1; |
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else printf("hostfs_args - unsupported option - %s\n", |
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options); |
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} |
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options = ptr; |
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} |
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return 0; |
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} |
|
|
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__uml_setup("hostfs=", hostfs_args, |
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"hostfs=<root dir>,<flags>,...\n" |
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" This is used to set hostfs parameters. The root directory argument\n" |
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" is used to confine all hostfs mounts to within the specified directory\n" |
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" tree on the host. If this isn't specified, then a user inside UML can\n" |
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" mount anything on the host that's accessible to the user that's running\n" |
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" it.\n" |
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" The only flag currently supported is 'append', which specifies that all\n" |
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" files opened by hostfs will be opened in append mode.\n\n" |
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); |
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#endif |
|
|
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static char *__dentry_name(struct dentry *dentry, char *name) |
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{ |
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char *p = dentry_path_raw(dentry, name, PATH_MAX); |
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char *root; |
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size_t len; |
|
|
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root = dentry->d_sb->s_fs_info; |
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len = strlen(root); |
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if (IS_ERR(p)) { |
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__putname(name); |
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return NULL; |
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} |
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|
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/* |
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* This function relies on the fact that dentry_path_raw() will place |
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* the path name at the end of the provided buffer. |
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*/ |
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BUG_ON(p + strlen(p) + 1 != name + PATH_MAX); |
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|
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strlcpy(name, root, PATH_MAX); |
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if (len > p - name) { |
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__putname(name); |
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return NULL; |
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} |
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|
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if (p > name + len) |
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strcpy(name + len, p); |
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|
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return name; |
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} |
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|
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static char *dentry_name(struct dentry *dentry) |
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{ |
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char *name = __getname(); |
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if (!name) |
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return NULL; |
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|
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return __dentry_name(dentry, name); |
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} |
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|
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static char *inode_name(struct inode *ino) |
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{ |
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struct dentry *dentry; |
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char *name; |
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|
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dentry = d_find_alias(ino); |
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if (!dentry) |
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return NULL; |
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|
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name = dentry_name(dentry); |
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|
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dput(dentry); |
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|
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return name; |
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} |
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|
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static char *follow_link(char *link) |
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{ |
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char *name, *resolved, *end; |
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int n; |
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|
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name = kmalloc(PATH_MAX, GFP_KERNEL); |
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if (!name) { |
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n = -ENOMEM; |
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goto out_free; |
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} |
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|
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n = hostfs_do_readlink(link, name, PATH_MAX); |
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if (n < 0) |
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goto out_free; |
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else if (n == PATH_MAX) { |
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n = -E2BIG; |
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goto out_free; |
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} |
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|
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if (*name == '/') |
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return name; |
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|
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end = strrchr(link, '/'); |
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if (end == NULL) |
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return name; |
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|
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*(end + 1) = '\0'; |
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|
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resolved = kasprintf(GFP_KERNEL, "%s%s", link, name); |
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if (resolved == NULL) { |
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n = -ENOMEM; |
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goto out_free; |
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} |
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|
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kfree(name); |
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return resolved; |
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|
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out_free: |
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kfree(name); |
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return ERR_PTR(n); |
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} |
|
|
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static struct inode *hostfs_iget(struct super_block *sb) |
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{ |
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struct inode *inode = new_inode(sb); |
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if (!inode) |
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return ERR_PTR(-ENOMEM); |
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return inode; |
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} |
|
|
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static int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) |
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{ |
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/* |
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* do_statfs uses struct statfs64 internally, but the linux kernel |
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* struct statfs still has 32-bit versions for most of these fields, |
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* so we convert them here |
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*/ |
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int err; |
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long long f_blocks; |
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long long f_bfree; |
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long long f_bavail; |
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long long f_files; |
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long long f_ffree; |
|
|
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err = do_statfs(dentry->d_sb->s_fs_info, |
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&sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, |
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&f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), |
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&sf->f_namelen); |
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if (err) |
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return err; |
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sf->f_blocks = f_blocks; |
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sf->f_bfree = f_bfree; |
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sf->f_bavail = f_bavail; |
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sf->f_files = f_files; |
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sf->f_ffree = f_ffree; |
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sf->f_type = HOSTFS_SUPER_MAGIC; |
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return 0; |
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} |
|
|
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static struct inode *hostfs_alloc_inode(struct super_block *sb) |
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{ |
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struct hostfs_inode_info *hi; |
|
|
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hi = alloc_inode_sb(sb, hostfs_inode_cache, GFP_KERNEL_ACCOUNT); |
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if (hi == NULL) |
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return NULL; |
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hi->fd = -1; |
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hi->mode = 0; |
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inode_init_once(&hi->vfs_inode); |
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mutex_init(&hi->open_mutex); |
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return &hi->vfs_inode; |
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} |
|
|
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static void hostfs_evict_inode(struct inode *inode) |
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{ |
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truncate_inode_pages_final(&inode->i_data); |
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clear_inode(inode); |
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if (HOSTFS_I(inode)->fd != -1) { |
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close_file(&HOSTFS_I(inode)->fd); |
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HOSTFS_I(inode)->fd = -1; |
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} |
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} |
|
|
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static void hostfs_free_inode(struct inode *inode) |
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{ |
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kmem_cache_free(hostfs_inode_cache, HOSTFS_I(inode)); |
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} |
|
|
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static int hostfs_show_options(struct seq_file *seq, struct dentry *root) |
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{ |
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const char *root_path = root->d_sb->s_fs_info; |
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size_t offset = strlen(root_ino) + 1; |
|
|
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if (strlen(root_path) > offset) |
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seq_show_option(seq, root_path + offset, NULL); |
|
|
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if (append) |
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seq_puts(seq, ",append"); |
|
|
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return 0; |
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} |
|
|
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static const struct super_operations hostfs_sbops = { |
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.alloc_inode = hostfs_alloc_inode, |
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.free_inode = hostfs_free_inode, |
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.evict_inode = hostfs_evict_inode, |
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.statfs = hostfs_statfs, |
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.show_options = hostfs_show_options, |
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}; |
|
|
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static int hostfs_readdir(struct file *file, struct dir_context *ctx) |
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{ |
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void *dir; |
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char *name; |
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unsigned long long next, ino; |
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int error, len; |
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unsigned int type; |
|
|
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name = dentry_name(file->f_path.dentry); |
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if (name == NULL) |
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return -ENOMEM; |
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dir = open_dir(name, &error); |
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__putname(name); |
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if (dir == NULL) |
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return -error; |
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next = ctx->pos; |
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seek_dir(dir, next); |
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while ((name = read_dir(dir, &next, &ino, &len, &type)) != NULL) { |
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if (!dir_emit(ctx, name, len, ino, type)) |
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break; |
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ctx->pos = next; |
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} |
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close_dir(dir); |
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return 0; |
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} |
|
|
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static int hostfs_open(struct inode *ino, struct file *file) |
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{ |
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char *name; |
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fmode_t mode; |
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int err; |
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int r, w, fd; |
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|
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mode = file->f_mode & (FMODE_READ | FMODE_WRITE); |
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if ((mode & HOSTFS_I(ino)->mode) == mode) |
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return 0; |
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|
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mode |= HOSTFS_I(ino)->mode; |
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|
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retry: |
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r = w = 0; |
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|
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if (mode & FMODE_READ) |
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r = 1; |
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if (mode & FMODE_WRITE) |
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r = w = 1; |
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|
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name = dentry_name(file_dentry(file)); |
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if (name == NULL) |
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return -ENOMEM; |
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|
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fd = open_file(name, r, w, append); |
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__putname(name); |
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if (fd < 0) |
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return fd; |
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|
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mutex_lock(&HOSTFS_I(ino)->open_mutex); |
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/* somebody else had handled it first? */ |
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if ((mode & HOSTFS_I(ino)->mode) == mode) { |
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mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
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close_file(&fd); |
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return 0; |
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} |
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if ((mode | HOSTFS_I(ino)->mode) != mode) { |
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mode |= HOSTFS_I(ino)->mode; |
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mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
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close_file(&fd); |
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goto retry; |
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} |
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if (HOSTFS_I(ino)->fd == -1) { |
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HOSTFS_I(ino)->fd = fd; |
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} else { |
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err = replace_file(fd, HOSTFS_I(ino)->fd); |
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close_file(&fd); |
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if (err < 0) { |
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mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
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return err; |
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} |
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} |
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HOSTFS_I(ino)->mode = mode; |
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mutex_unlock(&HOSTFS_I(ino)->open_mutex); |
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|
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return 0; |
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} |
|
|
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static int hostfs_file_release(struct inode *inode, struct file *file) |
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{ |
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filemap_write_and_wait(inode->i_mapping); |
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|
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return 0; |
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} |
|
|
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static int hostfs_fsync(struct file *file, loff_t start, loff_t end, |
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int datasync) |
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{ |
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struct inode *inode = file->f_mapping->host; |
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int ret; |
|
|
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ret = file_write_and_wait_range(file, start, end); |
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if (ret) |
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return ret; |
|
|
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inode_lock(inode); |
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ret = fsync_file(HOSTFS_I(inode)->fd, datasync); |
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inode_unlock(inode); |
|
|
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return ret; |
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} |
|
|
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static const struct file_operations hostfs_file_fops = { |
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.llseek = generic_file_llseek, |
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.splice_read = generic_file_splice_read, |
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.splice_write = iter_file_splice_write, |
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.read_iter = generic_file_read_iter, |
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.write_iter = generic_file_write_iter, |
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.mmap = generic_file_mmap, |
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.open = hostfs_open, |
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.release = hostfs_file_release, |
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.fsync = hostfs_fsync, |
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}; |
|
|
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static const struct file_operations hostfs_dir_fops = { |
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.llseek = generic_file_llseek, |
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.iterate_shared = hostfs_readdir, |
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.read = generic_read_dir, |
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.open = hostfs_open, |
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.fsync = hostfs_fsync, |
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}; |
|
|
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static int hostfs_writepage(struct page *page, struct writeback_control *wbc) |
|
{ |
|
struct address_space *mapping = page->mapping; |
|
struct inode *inode = mapping->host; |
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char *buffer; |
|
loff_t base = page_offset(page); |
|
int count = PAGE_SIZE; |
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int end_index = inode->i_size >> PAGE_SHIFT; |
|
int err; |
|
|
|
if (page->index >= end_index) |
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count = inode->i_size & (PAGE_SIZE-1); |
|
|
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buffer = kmap(page); |
|
|
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err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); |
|
if (err != count) { |
|
if (err >= 0) |
|
err = -EIO; |
|
mapping_set_error(mapping, err); |
|
goto out; |
|
} |
|
|
|
if (base > inode->i_size) |
|
inode->i_size = base; |
|
|
|
err = 0; |
|
|
|
out: |
|
kunmap(page); |
|
|
|
unlock_page(page); |
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return err; |
|
} |
|
|
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static int hostfs_read_folio(struct file *file, struct folio *folio) |
|
{ |
|
struct page *page = &folio->page; |
|
char *buffer; |
|
loff_t start = page_offset(page); |
|
int bytes_read, ret = 0; |
|
|
|
buffer = kmap(page); |
|
bytes_read = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, |
|
PAGE_SIZE); |
|
if (bytes_read < 0) { |
|
ClearPageUptodate(page); |
|
SetPageError(page); |
|
ret = bytes_read; |
|
goto out; |
|
} |
|
|
|
memset(buffer + bytes_read, 0, PAGE_SIZE - bytes_read); |
|
|
|
ClearPageError(page); |
|
SetPageUptodate(page); |
|
|
|
out: |
|
flush_dcache_page(page); |
|
kunmap(page); |
|
unlock_page(page); |
|
return ret; |
|
} |
|
|
|
static int hostfs_write_begin(struct file *file, struct address_space *mapping, |
|
loff_t pos, unsigned len, |
|
struct page **pagep, void **fsdata) |
|
{ |
|
pgoff_t index = pos >> PAGE_SHIFT; |
|
|
|
*pagep = grab_cache_page_write_begin(mapping, index); |
|
if (!*pagep) |
|
return -ENOMEM; |
|
return 0; |
|
} |
|
|
|
static 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_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_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); |
|
put_page(page); |
|
|
|
return err; |
|
} |
|
|
|
static const struct address_space_operations hostfs_aops = { |
|
.writepage = hostfs_writepage, |
|
.read_folio = hostfs_read_folio, |
|
.dirty_folio = filemap_dirty_folio, |
|
.write_begin = hostfs_write_begin, |
|
.write_end = hostfs_write_end, |
|
}; |
|
|
|
static int read_name(struct inode *ino, char *name) |
|
{ |
|
dev_t rdev; |
|
struct hostfs_stat st; |
|
int err = stat_file(name, &st, -1); |
|
if (err) |
|
return err; |
|
|
|
/* Reencode maj and min with the kernel encoding.*/ |
|
rdev = MKDEV(st.maj, st.min); |
|
|
|
switch (st.mode & S_IFMT) { |
|
case S_IFLNK: |
|
ino->i_op = &hostfs_link_iops; |
|
break; |
|
case S_IFDIR: |
|
ino->i_op = &hostfs_dir_iops; |
|
ino->i_fop = &hostfs_dir_fops; |
|
break; |
|
case S_IFCHR: |
|
case S_IFBLK: |
|
case S_IFIFO: |
|
case S_IFSOCK: |
|
init_special_inode(ino, st.mode & S_IFMT, rdev); |
|
ino->i_op = &hostfs_iops; |
|
break; |
|
case S_IFREG: |
|
ino->i_op = &hostfs_iops; |
|
ino->i_fop = &hostfs_file_fops; |
|
ino->i_mapping->a_ops = &hostfs_aops; |
|
break; |
|
default: |
|
return -EIO; |
|
} |
|
|
|
ino->i_ino = st.ino; |
|
ino->i_mode = st.mode; |
|
set_nlink(ino, st.nlink); |
|
i_uid_write(ino, st.uid); |
|
i_gid_write(ino, st.gid); |
|
ino->i_atime = (struct timespec64){ st.atime.tv_sec, st.atime.tv_nsec }; |
|
ino->i_mtime = (struct timespec64){ st.mtime.tv_sec, st.mtime.tv_nsec }; |
|
ino->i_ctime = (struct timespec64){ st.ctime.tv_sec, st.ctime.tv_nsec }; |
|
ino->i_size = st.size; |
|
ino->i_blocks = st.blocks; |
|
return 0; |
|
} |
|
|
|
static int hostfs_create(struct user_namespace *mnt_userns, struct inode *dir, |
|
struct dentry *dentry, umode_t mode, bool excl) |
|
{ |
|
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 = -ENOMEM; |
|
name = dentry_name(dentry); |
|
if (name == NULL) |
|
goto out_put; |
|
|
|
fd = file_create(name, mode & 0777); |
|
if (fd < 0) |
|
error = fd; |
|
else |
|
error = read_name(inode, name); |
|
|
|
__putname(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; |
|
} |
|
|
|
static struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, |
|
unsigned int flags) |
|
{ |
|
struct inode *inode; |
|
char *name; |
|
int err; |
|
|
|
inode = hostfs_iget(ino->i_sb); |
|
if (IS_ERR(inode)) |
|
goto out; |
|
|
|
err = -ENOMEM; |
|
name = dentry_name(dentry); |
|
if (name) { |
|
err = read_name(inode, name); |
|
__putname(name); |
|
} |
|
if (err) { |
|
iput(inode); |
|
inode = (err == -ENOENT) ? NULL : ERR_PTR(err); |
|
} |
|
out: |
|
return d_splice_alias(inode, dentry); |
|
} |
|
|
|
static int hostfs_link(struct dentry *to, struct inode *ino, |
|
struct dentry *from) |
|
{ |
|
char *from_name, *to_name; |
|
int err; |
|
|
|
if ((from_name = dentry_name(from)) == NULL) |
|
return -ENOMEM; |
|
to_name = dentry_name(to); |
|
if (to_name == NULL) { |
|
__putname(from_name); |
|
return -ENOMEM; |
|
} |
|
err = link_file(to_name, from_name); |
|
__putname(from_name); |
|
__putname(to_name); |
|
return err; |
|
} |
|
|
|
static int hostfs_unlink(struct inode *ino, struct dentry *dentry) |
|
{ |
|
char *file; |
|
int err; |
|
|
|
if (append) |
|
return -EPERM; |
|
|
|
if ((file = dentry_name(dentry)) == NULL) |
|
return -ENOMEM; |
|
|
|
err = unlink_file(file); |
|
__putname(file); |
|
return err; |
|
} |
|
|
|
static int hostfs_symlink(struct user_namespace *mnt_userns, struct inode *ino, |
|
struct dentry *dentry, const char *to) |
|
{ |
|
char *file; |
|
int err; |
|
|
|
if ((file = dentry_name(dentry)) == NULL) |
|
return -ENOMEM; |
|
err = make_symlink(file, to); |
|
__putname(file); |
|
return err; |
|
} |
|
|
|
static int hostfs_mkdir(struct user_namespace *mnt_userns, struct inode *ino, |
|
struct dentry *dentry, umode_t mode) |
|
{ |
|
char *file; |
|
int err; |
|
|
|
if ((file = dentry_name(dentry)) == NULL) |
|
return -ENOMEM; |
|
err = do_mkdir(file, mode); |
|
__putname(file); |
|
return err; |
|
} |
|
|
|
static int hostfs_rmdir(struct inode *ino, struct dentry *dentry) |
|
{ |
|
char *file; |
|
int err; |
|
|
|
if ((file = dentry_name(dentry)) == NULL) |
|
return -ENOMEM; |
|
err = hostfs_do_rmdir(file); |
|
__putname(file); |
|
return err; |
|
} |
|
|
|
static int hostfs_mknod(struct user_namespace *mnt_userns, struct inode *dir, |
|
struct dentry *dentry, umode_t 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 = -ENOMEM; |
|
name = dentry_name(dentry); |
|
if (name == NULL) |
|
goto out_put; |
|
|
|
err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); |
|
if (err) |
|
goto out_free; |
|
|
|
err = read_name(inode, name); |
|
__putname(name); |
|
if (err) |
|
goto out_put; |
|
|
|
d_instantiate(dentry, inode); |
|
return 0; |
|
|
|
out_free: |
|
__putname(name); |
|
out_put: |
|
iput(inode); |
|
out: |
|
return err; |
|
} |
|
|
|
static int hostfs_rename2(struct user_namespace *mnt_userns, |
|
struct inode *old_dir, struct dentry *old_dentry, |
|
struct inode *new_dir, struct dentry *new_dentry, |
|
unsigned int flags) |
|
{ |
|
char *old_name, *new_name; |
|
int err; |
|
|
|
if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) |
|
return -EINVAL; |
|
|
|
old_name = dentry_name(old_dentry); |
|
if (old_name == NULL) |
|
return -ENOMEM; |
|
new_name = dentry_name(new_dentry); |
|
if (new_name == NULL) { |
|
__putname(old_name); |
|
return -ENOMEM; |
|
} |
|
if (!flags) |
|
err = rename_file(old_name, new_name); |
|
else |
|
err = rename2_file(old_name, new_name, flags); |
|
|
|
__putname(old_name); |
|
__putname(new_name); |
|
return err; |
|
} |
|
|
|
static int hostfs_permission(struct user_namespace *mnt_userns, |
|
struct inode *ino, int desired) |
|
{ |
|
char *name; |
|
int r = 0, w = 0, x = 0, err; |
|
|
|
if (desired & MAY_NOT_BLOCK) |
|
return -ECHILD; |
|
|
|
if (desired & MAY_READ) r = 1; |
|
if (desired & MAY_WRITE) w = 1; |
|
if (desired & MAY_EXEC) x = 1; |
|
name = inode_name(ino); |
|
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); |
|
__putname(name); |
|
if (!err) |
|
err = generic_permission(&init_user_ns, ino, desired); |
|
return err; |
|
} |
|
|
|
static int hostfs_setattr(struct user_namespace *mnt_userns, |
|
struct dentry *dentry, struct iattr *attr) |
|
{ |
|
struct inode *inode = d_inode(dentry); |
|
struct hostfs_iattr attrs; |
|
char *name; |
|
int err; |
|
|
|
int fd = HOSTFS_I(inode)->fd; |
|
|
|
err = setattr_prepare(&init_user_ns, dentry, 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 = from_kuid(&init_user_ns, attr->ia_uid); |
|
} |
|
if (attr->ia_valid & ATTR_GID) { |
|
attrs.ia_valid |= HOSTFS_ATTR_GID; |
|
attrs.ia_gid = from_kgid(&init_user_ns, 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 = (struct hostfs_timespec) |
|
{ attr->ia_atime.tv_sec, attr->ia_atime.tv_nsec }; |
|
} |
|
if (attr->ia_valid & ATTR_MTIME) { |
|
attrs.ia_valid |= HOSTFS_ATTR_MTIME; |
|
attrs.ia_mtime = (struct hostfs_timespec) |
|
{ attr->ia_mtime.tv_sec, attr->ia_mtime.tv_nsec }; |
|
} |
|
if (attr->ia_valid & ATTR_CTIME) { |
|
attrs.ia_valid |= HOSTFS_ATTR_CTIME; |
|
attrs.ia_ctime = (struct hostfs_timespec) |
|
{ attr->ia_ctime.tv_sec, attr->ia_ctime.tv_nsec }; |
|
} |
|
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); |
|
if (name == NULL) |
|
return -ENOMEM; |
|
err = set_attr(name, &attrs, fd); |
|
__putname(name); |
|
if (err) |
|
return err; |
|
|
|
if ((attr->ia_valid & ATTR_SIZE) && |
|
attr->ia_size != i_size_read(inode)) |
|
truncate_setsize(inode, attr->ia_size); |
|
|
|
setattr_copy(&init_user_ns, inode, attr); |
|
mark_inode_dirty(inode); |
|
return 0; |
|
} |
|
|
|
static const struct inode_operations hostfs_iops = { |
|
.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_rename2, |
|
.permission = hostfs_permission, |
|
.setattr = hostfs_setattr, |
|
}; |
|
|
|
static const char *hostfs_get_link(struct dentry *dentry, |
|
struct inode *inode, |
|
struct delayed_call *done) |
|
{ |
|
char *link; |
|
if (!dentry) |
|
return ERR_PTR(-ECHILD); |
|
link = kmalloc(PATH_MAX, GFP_KERNEL); |
|
if (link) { |
|
char *path = dentry_name(dentry); |
|
int err = -ENOMEM; |
|
if (path) { |
|
err = hostfs_do_readlink(path, link, PATH_MAX); |
|
if (err == PATH_MAX) |
|
err = -E2BIG; |
|
__putname(path); |
|
} |
|
if (err < 0) { |
|
kfree(link); |
|
return ERR_PTR(err); |
|
} |
|
} else { |
|
return ERR_PTR(-ENOMEM); |
|
} |
|
|
|
set_delayed_call(done, kfree_link, link); |
|
return link; |
|
} |
|
|
|
static const struct inode_operations hostfs_link_iops = { |
|
.get_link = hostfs_get_link, |
|
}; |
|
|
|
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_d_op = &simple_dentry_operations; |
|
sb->s_maxbytes = MAX_LFS_FILESIZE; |
|
err = super_setup_bdi(sb); |
|
if (err) |
|
goto out; |
|
|
|
/* NULL is printed as '(null)' by printf(): avoid that. */ |
|
if (req_root == NULL) |
|
req_root = ""; |
|
|
|
err = -ENOMEM; |
|
sb->s_fs_info = host_root_path = |
|
kasprintf(GFP_KERNEL, "%s/%s", root_ino, req_root); |
|
if (host_root_path == NULL) |
|
goto out; |
|
|
|
root_inode = new_inode(sb); |
|
if (!root_inode) |
|
goto out; |
|
|
|
err = read_name(root_inode, host_root_path); |
|
if (err) |
|
goto out_put; |
|
|
|
if (S_ISLNK(root_inode->i_mode)) { |
|
char *name = follow_link(host_root_path); |
|
if (IS_ERR(name)) { |
|
err = PTR_ERR(name); |
|
goto out_put; |
|
} |
|
err = read_name(root_inode, name); |
|
kfree(name); |
|
if (err) |
|
goto out_put; |
|
} |
|
|
|
err = -ENOMEM; |
|
sb->s_root = d_make_root(root_inode); |
|
if (sb->s_root == NULL) |
|
goto out; |
|
|
|
return 0; |
|
|
|
out_put: |
|
iput(root_inode); |
|
out: |
|
return err; |
|
} |
|
|
|
static struct dentry *hostfs_read_sb(struct file_system_type *type, |
|
int flags, const char *dev_name, |
|
void *data) |
|
{ |
|
return mount_nodev(type, flags, data, hostfs_fill_sb_common); |
|
} |
|
|
|
static void hostfs_kill_sb(struct super_block *s) |
|
{ |
|
kill_anon_super(s); |
|
kfree(s->s_fs_info); |
|
} |
|
|
|
static struct file_system_type hostfs_type = { |
|
.owner = THIS_MODULE, |
|
.name = "hostfs", |
|
.mount = hostfs_read_sb, |
|
.kill_sb = hostfs_kill_sb, |
|
.fs_flags = 0, |
|
}; |
|
MODULE_ALIAS_FS("hostfs"); |
|
|
|
static int __init init_hostfs(void) |
|
{ |
|
hostfs_inode_cache = KMEM_CACHE(hostfs_inode_info, 0); |
|
if (!hostfs_inode_cache) |
|
return -ENOMEM; |
|
return register_filesystem(&hostfs_type); |
|
} |
|
|
|
static void __exit exit_hostfs(void) |
|
{ |
|
unregister_filesystem(&hostfs_type); |
|
kmem_cache_destroy(hostfs_inode_cache); |
|
} |
|
|
|
module_init(init_hostfs) |
|
module_exit(exit_hostfs) |
|
MODULE_LICENSE("GPL");
|
|
|