| /* |
| * fs/sdcardfs/main.c |
| * |
| * Copyright (c) 2013 Samsung Electronics Co. Ltd |
| * Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun, |
| * Sunghwan Yun, Sungjong Seo |
| * |
| * This program has been developed as a stackable file system based on |
| * the WrapFS which written by |
| * |
| * Copyright (c) 1998-2011 Erez Zadok |
| * Copyright (c) 2009 Shrikar Archak |
| * Copyright (c) 2003-2011 Stony Brook University |
| * Copyright (c) 2003-2011 The Research Foundation of SUNY |
| * |
| * This file is dual licensed. It may be redistributed and/or modified |
| * under the terms of the Apache 2.0 License OR version 2 of the GNU |
| * General Public License. |
| */ |
| |
| #include "sdcardfs.h" |
| #include <linux/module.h> |
| #include <linux/types.h> |
| #include <linux/parser.h> |
| |
| enum { |
| Opt_uid, |
| Opt_gid, |
| Opt_wgid, |
| Opt_debug, |
| Opt_split, |
| Opt_derive, |
| Opt_lower_fs, |
| Opt_reserved_mb, |
| Opt_err, |
| }; |
| |
| static const match_table_t sdcardfs_tokens = { |
| {Opt_uid, "uid=%u"}, |
| {Opt_gid, "gid=%u"}, |
| {Opt_wgid, "wgid=%u"}, |
| {Opt_debug, "debug"}, |
| {Opt_split, "split"}, |
| {Opt_derive, "derive=%s"}, |
| {Opt_lower_fs, "lower_fs=%s"}, |
| {Opt_reserved_mb, "reserved_mb=%u"}, |
| {Opt_err, NULL} |
| }; |
| |
| static int parse_options(struct super_block *sb, char *options, int silent, |
| int *debug, struct sdcardfs_mount_options *opts) |
| { |
| char *p; |
| substring_t args[MAX_OPT_ARGS]; |
| int option; |
| char *string_option; |
| |
| /* by default, we use AID_MEDIA_RW as uid, gid */ |
| opts->fs_low_uid = AID_MEDIA_RW; |
| opts->fs_low_gid = AID_MEDIA_RW; |
| /* by default, we use AID_SDCARD_RW as write_gid */ |
| opts->write_gid = AID_SDCARD_RW; |
| /* default permission policy |
| * (DERIVE_NONE | DERIVE_LEGACY | DERIVE_UNIFIED) */ |
| opts->derive = DERIVE_NONE; |
| opts->split_perms = 0; |
| /* by default, we use LOWER_FS_EXT4 as lower fs type */ |
| opts->lower_fs = LOWER_FS_EXT4; |
| /* by default, 0MB is reserved */ |
| opts->reserved_mb = 0; |
| |
| *debug = 0; |
| |
| if (!options) |
| return 0; |
| |
| while ((p = strsep(&options, ",")) != NULL) { |
| int token; |
| if (!*p) |
| continue; |
| |
| token = match_token(p, sdcardfs_tokens, args); |
| |
| switch (token) { |
| case Opt_debug: |
| *debug = 1; |
| break; |
| case Opt_uid: |
| if (match_int(&args[0], &option)) |
| return 0; |
| opts->fs_low_uid = option; |
| break; |
| case Opt_gid: |
| if (match_int(&args[0], &option)) |
| return 0; |
| opts->fs_low_gid = option; |
| break; |
| case Opt_wgid: |
| if (match_int(&args[0], &option)) |
| return 0; |
| opts->write_gid = option; |
| break; |
| case Opt_split: |
| opts->split_perms=1; |
| break; |
| case Opt_derive: |
| string_option = match_strdup(&args[0]); |
| if (!strcmp("none", string_option)) { |
| opts->derive = DERIVE_NONE; |
| } else if (!strcmp("legacy", string_option)) { |
| opts->derive = DERIVE_LEGACY; |
| } else if (!strcmp("unified", string_option)) { |
| opts->derive = DERIVE_UNIFIED; |
| } else { |
| kfree(string_option); |
| goto invalid_option; |
| } |
| kfree(string_option); |
| break; |
| case Opt_lower_fs: |
| string_option = match_strdup(&args[0]); |
| if (!strcmp("ext4", string_option)) { |
| opts->lower_fs = LOWER_FS_EXT4; |
| } else if (!strcmp("fat", string_option)) { |
| opts->lower_fs = LOWER_FS_FAT; |
| } else { |
| kfree(string_option); |
| goto invalid_option; |
| } |
| kfree(string_option); |
| break; |
| case Opt_reserved_mb: |
| if (match_int(&args[0], &option)) |
| return 0; |
| opts->reserved_mb = option; |
| break; |
| /* unknown option */ |
| default: |
| invalid_option: |
| if (!silent) { |
| printk( KERN_ERR "Unrecognized mount option \"%s\" " |
| "or missing value", p); |
| } |
| return -EINVAL; |
| } |
| } |
| |
| if (*debug) { |
| printk( KERN_INFO "sdcardfs : options - debug:%d\n", *debug); |
| printk( KERN_INFO "sdcardfs : options - uid:%d\n", |
| opts->fs_low_uid); |
| printk( KERN_INFO "sdcardfs : options - gid:%d\n", |
| opts->fs_low_gid); |
| } |
| |
| return 0; |
| } |
| |
| #if 0 |
| /* |
| * our custom d_alloc_root work-alike |
| * |
| * we can't use d_alloc_root if we want to use our own interpose function |
| * unchanged, so we simply call our own "fake" d_alloc_root |
| */ |
| static struct dentry *sdcardfs_d_alloc_root(struct super_block *sb) |
| { |
| struct dentry *ret = NULL; |
| |
| if (sb) { |
| static const struct qstr name = { |
| .name = "/", |
| .len = 1 |
| }; |
| |
| ret = d_alloc(NULL, &name); |
| if (ret) { |
| d_set_d_op(ret, &sdcardfs_ci_dops); |
| ret->d_sb = sb; |
| ret->d_parent = ret; |
| } |
| } |
| return ret; |
| } |
| #endif |
| |
| /* |
| * There is no need to lock the sdcardfs_super_info's rwsem as there is no |
| * way anyone can have a reference to the superblock at this point in time. |
| */ |
| static int sdcardfs_read_super(struct super_block *sb, const char *dev_name, |
| void *raw_data, int silent) |
| { |
| int err = 0; |
| int debug; |
| struct super_block *lower_sb; |
| struct path lower_path; |
| struct sdcardfs_sb_info *sb_info; |
| void *pkgl_id; |
| struct inode *inode; |
| |
| printk(KERN_INFO "sdcardfs version 2.0\n"); |
| |
| if (!dev_name) { |
| printk(KERN_ERR |
| "sdcardfs: read_super: missing dev_name argument\n"); |
| err = -EINVAL; |
| goto out; |
| } |
| |
| printk(KERN_INFO "sdcardfs: dev_name -> %s\n", dev_name); |
| printk(KERN_INFO "sdcardfs: options -> %s\n", (char *)raw_data); |
| |
| /* parse lower path */ |
| err = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, |
| &lower_path); |
| if (err) { |
| printk(KERN_ERR "sdcardfs: error accessing " |
| "lower directory '%s'\n", dev_name); |
| goto out; |
| } |
| |
| /* allocate superblock private data */ |
| sb->s_fs_info = kzalloc(sizeof(struct sdcardfs_sb_info), GFP_KERNEL); |
| if (!SDCARDFS_SB(sb)) { |
| printk(KERN_CRIT "sdcardfs: read_super: out of memory\n"); |
| err = -ENOMEM; |
| goto out_free; |
| } |
| |
| sb_info = sb->s_fs_info; |
| |
| /* parse options */ |
| err = parse_options(sb, raw_data, silent, &debug, &sb_info->options); |
| if (err) { |
| printk(KERN_ERR "sdcardfs: invalid options\n"); |
| goto out_freesbi; |
| } |
| |
| if (sb_info->options.derive != DERIVE_NONE) { |
| pkgl_id = packagelist_create(sb_info->options.write_gid); |
| if(IS_ERR(pkgl_id)) |
| goto out_freesbi; |
| else |
| sb_info->pkgl_id = pkgl_id; |
| } |
| |
| /* set the lower superblock field of upper superblock */ |
| lower_sb = lower_path.dentry->d_sb; |
| atomic_inc(&lower_sb->s_active); |
| sdcardfs_set_lower_super(sb, lower_sb); |
| |
| /* inherit maxbytes from lower file system */ |
| sb->s_maxbytes = lower_sb->s_maxbytes; |
| |
| /* |
| * Our c/m/atime granularity is 1 ns because we may stack on file |
| * systems whose granularity is as good. |
| */ |
| sb->s_time_gran = 1; |
| |
| sb->s_magic = SDCARDFS_SUPER_MAGIC; |
| sb->s_op = &sdcardfs_sops; |
| |
| /* get a new inode and allocate our root dentry */ |
| inode = sdcardfs_iget(sb, lower_path.dentry->d_inode); |
| if (IS_ERR(inode)) { |
| err = PTR_ERR(inode); |
| goto out_sput; |
| } |
| sb->s_root = d_make_root(inode); |
| if (!sb->s_root) { |
| err = -ENOMEM; |
| goto out_iput; |
| } |
| d_set_d_op(sb->s_root, &sdcardfs_ci_dops); |
| |
| /* link the upper and lower dentries */ |
| sb->s_root->d_fsdata = NULL; |
| err = new_dentry_private_data(sb->s_root); |
| if (err) |
| goto out_freeroot; |
| |
| /* set the lower dentries for s_root */ |
| sdcardfs_set_lower_path(sb->s_root, &lower_path); |
| |
| /* |
| * No need to call interpose because we already have a positive |
| * dentry, which was instantiated by d_make_root. Just need to |
| * d_rehash it. |
| */ |
| d_rehash(sb->s_root); |
| |
| /* setup permission policy */ |
| switch(sb_info->options.derive) { |
| case DERIVE_NONE: |
| setup_derived_state(sb->s_root->d_inode, |
| PERM_ROOT, 0, AID_ROOT, AID_SDCARD_RW, 00775); |
| sb_info->obbpath_s = NULL; |
| break; |
| case DERIVE_LEGACY: |
| /* Legacy behavior used to support internal multiuser layout which |
| * places user_id at the top directory level, with the actual roots |
| * just below that. Shared OBB path is also at top level. */ |
| setup_derived_state(sb->s_root->d_inode, |
| PERM_LEGACY_PRE_ROOT, 0, AID_ROOT, AID_SDCARD_R, 00771); |
| /* initialize the obbpath string and lookup the path |
| * sb_info->obb_path will be deactivated by path_put |
| * on sdcardfs_put_super */ |
| sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL); |
| snprintf(sb_info->obbpath_s, PATH_MAX, "%s/obb", dev_name); |
| err = prepare_dir(sb_info->obbpath_s, |
| sb_info->options.fs_low_uid, |
| sb_info->options.fs_low_gid, 00755); |
| if(err) |
| printk(KERN_ERR "sdcardfs: %s: %d, error on creating %s\n", |
| __func__,__LINE__, sb_info->obbpath_s); |
| break; |
| case DERIVE_UNIFIED: |
| /* Unified multiuser layout which places secondary user_id under |
| * /Android/user and shared OBB path under /Android/obb. */ |
| setup_derived_state(sb->s_root->d_inode, |
| PERM_ROOT, 0, AID_ROOT, AID_SDCARD_R, 00771); |
| |
| sb_info->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL); |
| snprintf(sb_info->obbpath_s, PATH_MAX, "%s/Android/obb", dev_name); |
| break; |
| } |
| fix_derived_permission(sb->s_root->d_inode); |
| |
| if (!silent) |
| printk(KERN_INFO "sdcardfs: mounted on top of %s type %s\n", |
| dev_name, lower_sb->s_type->name); |
| goto out; /* all is well */ |
| |
| /* no longer needed: free_dentry_private_data(sb->s_root); */ |
| out_freeroot: |
| dput(sb->s_root); |
| out_iput: |
| iput(inode); |
| out_sput: |
| /* drop refs we took earlier */ |
| atomic_dec(&lower_sb->s_active); |
| packagelist_destroy(sb_info->pkgl_id); |
| out_freesbi: |
| kfree(SDCARDFS_SB(sb)); |
| sb->s_fs_info = NULL; |
| out_free: |
| path_put(&lower_path); |
| |
| out: |
| return err; |
| } |
| |
| /* A feature which supports mount_nodev() with options */ |
| static struct dentry *mount_nodev_with_options(struct file_system_type *fs_type, |
| int flags, const char *dev_name, void *data, |
| int (*fill_super)(struct super_block *, const char *, void *, int)) |
| |
| { |
| int error; |
| struct super_block *s = sget(fs_type, NULL, set_anon_super, flags, NULL); |
| |
| if (IS_ERR(s)) |
| return ERR_CAST(s); |
| |
| s->s_flags = flags; |
| |
| error = fill_super(s, dev_name, data, flags & MS_SILENT ? 1 : 0); |
| if (error) { |
| deactivate_locked_super(s); |
| return ERR_PTR(error); |
| } |
| s->s_flags |= MS_ACTIVE; |
| return dget(s->s_root); |
| } |
| |
| struct dentry *sdcardfs_mount(struct file_system_type *fs_type, int flags, |
| const char *dev_name, void *raw_data) |
| { |
| /* |
| * dev_name is a lower_path_name, |
| * raw_data is a option string. |
| */ |
| return mount_nodev_with_options(fs_type, flags, dev_name, |
| raw_data, sdcardfs_read_super); |
| } |
| |
| static struct file_system_type sdcardfs_fs_type = { |
| .owner = THIS_MODULE, |
| .name = SDCARDFS_NAME, |
| .mount = sdcardfs_mount, |
| .kill_sb = generic_shutdown_super, |
| .fs_flags = 0, |
| }; |
| |
| static int __init init_sdcardfs_fs(void) |
| { |
| int err; |
| |
| pr_info("Registering sdcardfs " SDCARDFS_VERSION "\n"); |
| |
| err = sdcardfs_init_inode_cache(); |
| if (err) |
| goto out; |
| err = sdcardfs_init_dentry_cache(); |
| if (err) |
| goto out; |
| err = packagelist_init(); |
| if (err) |
| goto out; |
| err = register_filesystem(&sdcardfs_fs_type); |
| out: |
| if (err) { |
| sdcardfs_destroy_inode_cache(); |
| sdcardfs_destroy_dentry_cache(); |
| packagelist_exit(); |
| } |
| return err; |
| } |
| |
| static void __exit exit_sdcardfs_fs(void) |
| { |
| sdcardfs_destroy_inode_cache(); |
| sdcardfs_destroy_dentry_cache(); |
| packagelist_exit(); |
| unregister_filesystem(&sdcardfs_fs_type); |
| pr_info("Completed sdcardfs module unload\n"); |
| } |
| |
| MODULE_AUTHOR("Erez Zadok, Filesystems and Storage Lab, Stony Brook University" |
| " (http://www.fsl.cs.sunysb.edu/)"); |
| MODULE_DESCRIPTION("Wrapfs " SDCARDFS_VERSION |
| " (http://wrapfs.filesystems.org/)"); |
| MODULE_LICENSE("GPL"); |
| |
| module_init(init_sdcardfs_fs); |
| module_exit(exit_sdcardfs_fs); |