1 files changed, 265 insertions, 0 deletions
diff --git a/fs/sdcardfs/derived_perm.c b/fs/sdcardfs/derived_perm.c
new file mode 100644
index 000000000000..128b3e56851f
--- /dev/null
+++ b/fs/sdcardfs/derived_perm.c
@@ -0,0 +1,265 @@
+/*
+ * fs/sdcardfs/derived_perm.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"
+
+/* copy derived state from parent inode */
+static void inherit_derived_state(struct inode *parent, struct inode *child)
+{
+	struct sdcardfs_inode_info *pi = SDCARDFS_I(parent);
+	struct sdcardfs_inode_info *ci = SDCARDFS_I(child);
+
+	ci->perm = PERM_INHERIT;
+	ci->userid = pi->userid;
+	ci->d_uid = pi->d_uid;
+	ci->under_android = pi->under_android;
+}
+
+/* helper function for derived state */
+void setup_derived_state(struct inode *inode, perm_t perm,
+                        userid_t userid, uid_t uid, bool under_android)
+{
+	struct sdcardfs_inode_info *info = SDCARDFS_I(inode);
+
+	info->perm = perm;
+	info->userid = userid;
+	info->d_uid = uid;
+	info->under_android = under_android;
+}
+
+/* While renaming, there is a point where we want the path from dentry, but the name from newdentry */
+void get_derived_permission_new(struct dentry *parent, struct dentry *dentry, struct dentry *newdentry)
+{
+	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
+	struct sdcardfs_inode_info *info = SDCARDFS_I(dentry->d_inode);
+	struct sdcardfs_inode_info *parent_info= SDCARDFS_I(parent->d_inode);
+	appid_t appid;
+
+	/* By default, each inode inherits from its parent.
+	 * the properties are maintained on its private fields
+	 * because the inode attributes will be modified with that of
+	 * its lower inode.
+	 * The derived state will be updated on the last
+	 * stage of each system call by fix_derived_permission(inode).
+	 */
+
+	inherit_derived_state(parent->d_inode, dentry->d_inode);
+
+	/* Derive custom permissions based on parent and current node */
+	switch (parent_info->perm) {
+		case PERM_INHERIT:
+			/* Already inherited above */
+			break;
+		case PERM_PRE_ROOT:
+			/* Legacy internal layout places users at top level */
+			info->perm = PERM_ROOT;
+			info->userid = simple_strtoul(newdentry->d_name.name, NULL, 10);
+			break;
+		case PERM_ROOT:
+			/* Assume masked off by default. */
+			if (!strcasecmp(newdentry->d_name.name, "Android")) {
+				/* App-specific directories inside; let anyone traverse */
+				info->perm = PERM_ANDROID;
+				info->under_android = true;
+			}
+			break;
+		case PERM_ANDROID:
+			if (!strcasecmp(newdentry->d_name.name, "data")) {
+				/* App-specific directories inside; let anyone traverse */
+				info->perm = PERM_ANDROID_DATA;
+			} else if (!strcasecmp(newdentry->d_name.name, "obb")) {
+				/* App-specific directories inside; let anyone traverse */
+				info->perm = PERM_ANDROID_OBB;
+				/* Single OBB directory is always shared */
+			} else if (!strcasecmp(newdentry->d_name.name, "media")) {
+				/* App-specific directories inside; let anyone traverse */
+				info->perm = PERM_ANDROID_MEDIA;
+			}
+			break;
+		case PERM_ANDROID_DATA:
+		case PERM_ANDROID_OBB:
+		case PERM_ANDROID_MEDIA:
+			appid = get_appid(sbi->pkgl_id, newdentry->d_name.name);
+			if (appid != 0) {
+				info->d_uid = multiuser_get_uid(parent_info->userid, appid);
+			}
+			break;
+	}
+}
+
+void get_derived_permission(struct dentry *parent, struct dentry *dentry)
+{
+	get_derived_permission_new(parent, dentry, dentry);
+}
+
+void get_derive_permissions_recursive(struct dentry *parent) {
+	struct dentry *dentry;
+	list_for_each_entry(dentry, &parent->d_subdirs, d_child) {
+		if (dentry && dentry->d_inode) {
+			mutex_lock(&dentry->d_inode->i_mutex);
+			get_derived_permission(parent, dentry);
+			fix_derived_permission(dentry->d_inode);
+			get_derive_permissions_recursive(dentry);
+			mutex_unlock(&dentry->d_inode->i_mutex);
+		}
+	}
+}
+
+/* main function for updating derived permission */
+inline void update_derived_permission_lock(struct dentry *dentry)
+{
+	struct dentry *parent;
+
+	if(!dentry || !dentry->d_inode) {
+		printk(KERN_ERR "sdcardfs: %s: invalid dentry\n", __func__);
+		return;
+	}
+	/* FIXME:
+	 * 1. need to check whether the dentry is updated or not
+	 * 2. remove the root dentry update
+	 */
+	mutex_lock(&dentry->d_inode->i_mutex);
+	if(IS_ROOT(dentry)) {
+		//setup_default_pre_root_state(dentry->d_inode);
+	} else {
+		parent = dget_parent(dentry);
+		if(parent) {
+			get_derived_permission(parent, dentry);
+			dput(parent);
+		}
+	}
+	fix_derived_permission(dentry->d_inode);
+	mutex_unlock(&dentry->d_inode->i_mutex);
+}
+
+int need_graft_path(struct dentry *dentry)
+{
+	int ret = 0;
+	struct dentry *parent = dget_parent(dentry);
+	struct sdcardfs_inode_info *parent_info= SDCARDFS_I(parent->d_inode);
+	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
+
+	if(parent_info->perm == PERM_ANDROID &&
+			!strcasecmp(dentry->d_name.name, "obb")) {
+
+		/* /Android/obb is the base obbpath of DERIVED_UNIFIED */
+		if(!(sbi->options.multiuser == false
+				&& parent_info->userid == 0)) {
+			ret = 1;
+		}
+	}
+	dput(parent);
+	return ret;
+}
+
+int is_obbpath_invalid(struct dentry *dent)
+{
+	int ret = 0;
+	struct sdcardfs_dentry_info *di = SDCARDFS_D(dent);
+	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dent->d_sb);
+	char *path_buf, *obbpath_s;
+
+	/* check the base obbpath has been changed.
+	 * this routine can check an uninitialized obb dentry as well.
+	 * regarding the uninitialized obb, refer to the sdcardfs_mkdir() */
+	spin_lock(&di->lock);
+	if(di->orig_path.dentry) {
+ 		if(!di->lower_path.dentry) {
+			ret = 1;
+		} else {
+			path_get(&di->lower_path);
+			//lower_parent = lock_parent(lower_path->dentry);
+
+			path_buf = kmalloc(PATH_MAX, GFP_ATOMIC);
+			if(!path_buf) {
+				ret = 1;
+				printk(KERN_ERR "sdcardfs: fail to allocate path_buf in %s.\n", __func__);
+			} else {
+				obbpath_s = d_path(&di->lower_path, path_buf, PATH_MAX);
+				if (d_unhashed(di->lower_path.dentry) ||
+					strcasecmp(sbi->obbpath_s, obbpath_s)) {
+					ret = 1;
+				}
+				kfree(path_buf);
+			}
+
+			//unlock_dir(lower_parent);
+			path_put(&di->lower_path);
+		}
+	}
+	spin_unlock(&di->lock);
+	return ret;
+}
+
+int is_base_obbpath(struct dentry *dentry)
+{
+	int ret = 0;
+	struct dentry *parent = dget_parent(dentry);
+	struct sdcardfs_inode_info *parent_info= SDCARDFS_I(parent->d_inode);
+	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
+
+	spin_lock(&SDCARDFS_D(dentry)->lock);
+	if (sbi->options.multiuser) {
+		if(parent_info->perm == PERM_PRE_ROOT &&
+				!strcasecmp(dentry->d_name.name, "obb")) {
+			ret = 1;
+		}
+	} else  if (parent_info->perm == PERM_ANDROID &&
+			!strcasecmp(dentry->d_name.name, "obb")) {
+		ret = 1;
+	}
+	spin_unlock(&SDCARDFS_D(dentry)->lock);
+	return ret;
+}
+
+/* The lower_path will be stored to the dentry's orig_path
+ * and the base obbpath will be copyed to the lower_path variable.
+ * if an error returned, there's no change in the lower_path
+ * returns: -ERRNO if error (0: no error) */
+int setup_obb_dentry(struct dentry *dentry, struct path *lower_path)
+{
+	int err = 0;
+	struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
+	struct path obbpath;
+
+	/* A local obb dentry must have its own orig_path to support rmdir
+	 * and mkdir of itself. Usually, we expect that the sbi->obbpath
+	 * is avaiable on this stage. */
+	sdcardfs_set_orig_path(dentry, lower_path);
+
+	err = kern_path(sbi->obbpath_s,
+			LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &obbpath);
+
+	if(!err) {
+		/* the obbpath base has been found */
+		printk(KERN_INFO "sdcardfs: the sbi->obbpath is found\n");
+		pathcpy(lower_path, &obbpath);
+	} else {
+		/* if the sbi->obbpath is not available, we can optionally
+		 * setup the lower_path with its orig_path.
+		 * but, the current implementation just returns an error
+		 * because the sdcard daemon also regards this case as
+		 * a lookup fail. */
+		printk(KERN_INFO "sdcardfs: the sbi->obbpath is not available\n");
+	}
+	return err;
+}
+
+