sdcardfs: Bring up to date with Android M permissions:

In M, the workings of sdcardfs were changed significantly.
This brings sdcardfs into line with the changes.

Change-Id: I10e91a84a884c838feef7aa26c0a2b21f02e052e

1 files changed, 61 insertions, 80 deletions

diff --git a/fs/sdcardfs/main.c b/fs/sdcardfs/main.c
index 9d04ae8ceb46..80aa355d801e 100644
--- a/fs/sdcardfs/main.c
+++ b/fs/sdcardfs/main.c
@@ -24,25 +24,27 @@
 #include <linux/parser.h>
 
 enum {
-	Opt_uid,
+	Opt_fsuid,
+	Opt_fsgid,
 	Opt_gid,
-	Opt_wgid,
 	Opt_debug,
-	Opt_split,
-	Opt_derive,
 	Opt_lower_fs,
+	Opt_mask,
+	Opt_multiuser, // May need?
+	Opt_userid,
 	Opt_reserved_mb,
 	Opt_err,
 };
 
 static const match_table_t sdcardfs_tokens = {
-	{Opt_uid, "uid=%u"},
+	{Opt_fsuid, "fsuid=%u"},
+	{Opt_fsgid, "fsgid=%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_mask, "mask=%u"},
+	{Opt_userid, "userid=%d"},
+	{Opt_multiuser, "multiuser"},
 	{Opt_reserved_mb, "reserved_mb=%u"},
 	{Opt_err, NULL}
 };
@@ -58,12 +60,10 @@ static int parse_options(struct super_block *sb, char *options, int silent,
 	/* 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;
+	opts->mask = 0;
+	opts->multiuser = false;
+	opts->fs_user_id = 0;
+	opts->gid = 0;
 	/* by default, we use LOWER_FS_EXT4 as lower fs type */
 	opts->lower_fs = LOWER_FS_EXT4;
 	/* by default, 0MB is reserved */
@@ -85,37 +85,33 @@ static int parse_options(struct super_block *sb, char *options, int silent,
 		case Opt_debug:
 			*debug = 1;
 			break;
-		case Opt_uid:
+		case Opt_fsuid:
 			if (match_int(&args[0], &option))
 				return 0;
 			opts->fs_low_uid = option;
 			break;
-		case Opt_gid:
+		case Opt_fsgid:
 			if (match_int(&args[0], &option))
 				return 0;
 			opts->fs_low_gid = option;
 			break;
-		case Opt_wgid:
+		case Opt_gid:
 			if (match_int(&args[0], &option))
 				return 0;
-			opts->write_gid = option;
+			opts->gid = option;
 			break;
-		case Opt_split:
-			opts->split_perms=1;
+		case Opt_userid:
+			if (match_int(&args[0], &option))
+				return 0;
+			opts->fs_user_id = option;
 			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);
+		case Opt_mask:
+			if (match_int(&args[0], &option))
+				return 0;
+			opts->mask = option;
+			break;
+		case Opt_multiuser:
+			opts->multiuser = true;
 			break;
 		case Opt_lower_fs:
 			string_option = match_strdup(&args[0]);
@@ -184,6 +180,11 @@ static struct dentry *sdcardfs_d_alloc_root(struct super_block *sb)
 }
 #endif
 
+DEFINE_MUTEX(sdcardfs_super_list_lock);
+LIST_HEAD(sdcardfs_super_list);
+EXPORT_SYMBOL_GPL(sdcardfs_super_list_lock);
+EXPORT_SYMBOL_GPL(sdcardfs_super_list);
+
 /*
  * 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.
@@ -196,7 +197,6 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
 	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");
@@ -215,8 +215,7 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
 	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);
+		printk(KERN_ERR	"sdcardfs: error accessing lower directory '%s'\n", dev_name);
 		goto out;
 	}
 
@@ -229,7 +228,6 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
 	}
 
 	sb_info = sb->s_fs_info;
-
 	/* parse options */
 	err = parse_options(sb, raw_data, silent, &debug, &sb_info->options);
 	if (err) {
@@ -237,14 +235,6 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
 		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);
@@ -263,7 +253,7 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
 	sb->s_op = &sdcardfs_sops;
 
 	/* get a new inode and allocate our root dentry */
-	inode = sdcardfs_iget(sb, lower_path.dentry->d_inode);
+	inode = sdcardfs_iget(sb, lower_path.dentry->d_inode, 0);
 	if (IS_ERR(inode)) {
 		err = PTR_ERR(inode);
 		goto out_sput;
@@ -292,41 +282,22 @@ static int sdcardfs_read_super(struct super_block *sb, const char *dev_name,
 	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->obbpath_s = kzalloc(PATH_MAX, GFP_KERNEL);
+	mutex_lock(&sdcardfs_super_list_lock);
+	if(sb_info->options.multiuser) {
+		setup_derived_state(sb->s_root->d_inode, PERM_PRE_ROOT, sb_info->options.fs_user_id, AID_ROOT, false);
+		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;
+					sb_info->options.fs_low_gid, 00755);*/
+	} else {
+		setup_derived_state(sb->s_root->d_inode, PERM_ROOT, sb_info->options.fs_low_uid, AID_ROOT, false);
+		snprintf(sb_info->obbpath_s, PATH_MAX, "%s/Android/obb", dev_name);
 	}
 	fix_derived_permission(sb->s_root->d_inode);
+	sb_info->sb = sb;
+	list_add(&sb_info->list, &sdcardfs_super_list);
+	mutex_unlock(&sdcardfs_super_list_lock);
 
 	if (!silent)
 		printk(KERN_INFO "sdcardfs: mounted on top of %s type %s\n",
@@ -341,7 +312,6 @@ out_iput:
 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;
@@ -386,11 +356,22 @@ struct dentry *sdcardfs_mount(struct file_system_type *fs_type, int flags,
 					raw_data, sdcardfs_read_super);
 }
 
+void sdcardfs_kill_sb(struct super_block *sb) {
+	struct sdcardfs_sb_info *sbi;
+	if (sb->s_magic == SDCARDFS_SUPER_MAGIC) {
+		sbi = SDCARDFS_SB(sb);
+		mutex_lock(&sdcardfs_super_list_lock);
+		list_del(&sbi->list);
+		mutex_unlock(&sdcardfs_super_list_lock);
+	}
+	generic_shutdown_super(sb);
+}
+
 static struct file_system_type sdcardfs_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= SDCARDFS_NAME,
 	.mount		= sdcardfs_mount,
-	.kill_sb	= generic_shutdown_super,
+	.kill_sb	= sdcardfs_kill_sb,
 	.fs_flags	= 0,
 };