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-rw-r--r--fs/sdcardfs/main.c439
1 files changed, 439 insertions, 0 deletions
diff --git a/fs/sdcardfs/main.c b/fs/sdcardfs/main.c
new file mode 100644
index 00000000..d8695702
--- /dev/null
+++ b/fs/sdcardfs/main.c
@@ -0,0 +1,439 @@
+/*
+ * 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>
+#include "../internal.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;
+}
+
+/*
+ * 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 struct qstr name = {
+ .name = "/",
+ };
+ name.len=1;
+ ret = __d_alloc(sb, &name);
+ if (ret) {
+ d_set_d_op(ret, &sdcardfs_ci_dops);
+ ret->d_parent = ret;
+ }
+ }
+ return ret;
+}
+
+/*
+ * 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;
+
+ 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;
+
+#ifdef CONFIG_SECURITY
+ sb_info->cred = NULL;
+#endif
+
+ /* 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;
+
+ /* see comment next to the definition of sdcardfs_d_alloc_root */
+ sb->s_root = sdcardfs_d_alloc_root(sb);
+ if (!sb->s_root) {
+ err = -ENOMEM;
+ goto out_sput;
+ }
+
+ /* 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);
+
+ /* call interpose to create the upper level inode */
+ err = sdcardfs_interpose(sb->s_root, sb, &lower_path);
+ if (!err) {
+ /* 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;
+ }
+ /* else error: fall through */
+
+ free_dentry_private_data(sb->s_root);
+out_freeroot:
+ dput(sb->s_root);
+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;
+}
+
+#ifdef CONFIG_SECURITY
+static inline void fill_cred(struct super_block *s)
+{
+ struct sdcardfs_sb_info *sbi = SDCARDFS_SB(s);
+ sbi->cred = prepare_creds();
+}
+#endif
+
+/* 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);
+ }
+#ifdef CONFIG_SECURITY
+ fill_cred(s);
+#endif
+ 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);
generated by cgit v1.3.1 (git 2.54.0) at 2026-08-15 17:24:01 +0000