1 files changed, 356 insertions, 0 deletions
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
new file mode 100644
index 00000000..feb2d693
--- /dev/null
+++ b/fs/sysfs/inode.c
@@ -0,0 +1,356 @@
+/*
+ * fs/sysfs/inode.c - basic sysfs inode and dentry operations
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
+ *
+ * This file is released under the GPLv2.
+ *
+ * Please see Documentation/filesystems/sysfs.txt for more information.
+ */
+
+#undef DEBUG 
+
+#include <linux/pagemap.h>
+#include <linux/namei.h>
+#include <linux/backing-dev.h>
+#include <linux/capability.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/xattr.h>
+#include <linux/security.h>
+#include "sysfs.h"
+
+extern struct super_block * sysfs_sb;
+
+static const struct address_space_operations sysfs_aops = {
+	.readpage	= simple_readpage,
+	.write_begin	= simple_write_begin,
+	.write_end	= simple_write_end,
+};
+
+static struct backing_dev_info sysfs_backing_dev_info = {
+	.name		= "sysfs",
+	.ra_pages	= 0,	/* No readahead */
+	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
+};
+
+static const struct inode_operations sysfs_inode_operations ={
+	.permission	= sysfs_permission,
+	.setattr	= sysfs_setattr,
+	.getattr	= sysfs_getattr,
+	.setxattr	= sysfs_setxattr,
+};
+
+int __init sysfs_inode_init(void)
+{
+	return bdi_init(&sysfs_backing_dev_info);
+}
+
+static struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd)
+{
+	struct sysfs_inode_attrs *attrs;
+	struct iattr *iattrs;
+
+	attrs = kzalloc(sizeof(struct sysfs_inode_attrs), GFP_KERNEL);
+	if (!attrs)
+		return NULL;
+	iattrs = &attrs->ia_iattr;
+
+	/* assign default attributes */
+	iattrs->ia_mode = sd->s_mode;
+	iattrs->ia_uid = 0;
+	iattrs->ia_gid = 0;
+	iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME;
+
+	return attrs;
+}
+
+int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr * iattr)
+{
+	struct sysfs_inode_attrs *sd_attrs;
+	struct iattr *iattrs;
+	unsigned int ia_valid = iattr->ia_valid;
+
+	sd_attrs = sd->s_iattr;
+
+	if (!sd_attrs) {
+		/* setting attributes for the first time, allocate now */
+		sd_attrs = sysfs_init_inode_attrs(sd);
+		if (!sd_attrs)
+			return -ENOMEM;
+		sd->s_iattr = sd_attrs;
+	}
+	/* attributes were changed at least once in past */
+	iattrs = &sd_attrs->ia_iattr;
+
+	if (ia_valid & ATTR_UID)
+		iattrs->ia_uid = iattr->ia_uid;
+	if (ia_valid & ATTR_GID)
+		iattrs->ia_gid = iattr->ia_gid;
+	if (ia_valid & ATTR_ATIME)
+		iattrs->ia_atime = iattr->ia_atime;
+	if (ia_valid & ATTR_MTIME)
+		iattrs->ia_mtime = iattr->ia_mtime;
+	if (ia_valid & ATTR_CTIME)
+		iattrs->ia_ctime = iattr->ia_ctime;
+	if (ia_valid & ATTR_MODE) {
+		umode_t mode = iattr->ia_mode;
+		iattrs->ia_mode = sd->s_mode = mode;
+	}
+	return 0;
+}
+
+int sysfs_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+	struct inode *inode = dentry->d_inode;
+	struct sysfs_dirent *sd = dentry->d_fsdata;
+	int error;
+
+	if (!sd)
+		return -EINVAL;
+
+	mutex_lock(&sysfs_mutex);
+	error = inode_change_ok(inode, iattr);
+	if (error)
+		goto out;
+
+	error = sysfs_sd_setattr(sd, iattr);
+	if (error)
+		goto out;
+
+	/* this ignores size changes */
+	setattr_copy(inode, iattr);
+
+out:
+	mutex_unlock(&sysfs_mutex);
+	return error;
+}
+
+static int sysfs_sd_setsecdata(struct sysfs_dirent *sd, void **secdata, u32 *secdata_len)
+{
+	struct sysfs_inode_attrs *iattrs;
+	void *old_secdata;
+	size_t old_secdata_len;
+
+	if (!sd->s_iattr) {
+		sd->s_iattr = sysfs_init_inode_attrs(sd);
+		if (!sd->s_iattr)
+			return -ENOMEM;
+	}
+
+	iattrs = sd->s_iattr;
+	old_secdata = iattrs->ia_secdata;
+	old_secdata_len = iattrs->ia_secdata_len;
+
+	iattrs->ia_secdata = *secdata;
+	iattrs->ia_secdata_len = *secdata_len;
+
+	*secdata = old_secdata;
+	*secdata_len = old_secdata_len;
+	return 0;
+}
+
+int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,
+		size_t size, int flags)
+{
+	struct sysfs_dirent *sd = dentry->d_fsdata;
+	void *secdata;
+	int error;
+	u32 secdata_len = 0;
+
+	if (!sd)
+		return -EINVAL;
+
+	if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) {
+		const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
+		error = security_inode_setsecurity(dentry->d_inode, suffix,
+						value, size, flags);
+		if (error)
+			goto out;
+		error = security_inode_getsecctx(dentry->d_inode,
+						&secdata, &secdata_len);
+		if (error)
+			goto out;
+
+		mutex_lock(&sysfs_mutex);
+		error = sysfs_sd_setsecdata(sd, &secdata, &secdata_len);
+		mutex_unlock(&sysfs_mutex);
+
+		if (secdata)
+			security_release_secctx(secdata, secdata_len);
+	} else
+		return -EINVAL;
+out:
+	return error;
+}
+
+static inline void set_default_inode_attr(struct inode * inode, umode_t mode)
+{
+	inode->i_mode = mode;
+	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+}
+
+static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
+{
+	inode->i_uid = iattr->ia_uid;
+	inode->i_gid = iattr->ia_gid;
+	inode->i_atime = iattr->ia_atime;
+	inode->i_mtime = iattr->ia_mtime;
+	inode->i_ctime = iattr->ia_ctime;
+}
+
+static void sysfs_refresh_inode(struct sysfs_dirent *sd, struct inode *inode)
+{
+	struct sysfs_inode_attrs *iattrs = sd->s_iattr;
+
+	inode->i_mode = sd->s_mode;
+	if (iattrs) {
+		/* sysfs_dirent has non-default attributes
+		 * get them from persistent copy in sysfs_dirent
+		 */
+		set_inode_attr(inode, &iattrs->ia_iattr);
+		security_inode_notifysecctx(inode,
+					    iattrs->ia_secdata,
+					    iattrs->ia_secdata_len);
+	}
+
+	if (sysfs_type(sd) == SYSFS_DIR)
+		set_nlink(inode, sd->s_dir.subdirs + 2);
+}
+
+int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
+{
+	struct sysfs_dirent *sd = dentry->d_fsdata;
+	struct inode *inode = dentry->d_inode;
+
+	mutex_lock(&sysfs_mutex);
+	sysfs_refresh_inode(sd, inode);
+	mutex_unlock(&sysfs_mutex);
+
+	generic_fillattr(inode, stat);
+	return 0;
+}
+
+static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
+{
+	struct bin_attribute *bin_attr;
+
+	inode->i_private = sysfs_get(sd);
+	inode->i_mapping->a_ops = &sysfs_aops;
+	inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
+	inode->i_op = &sysfs_inode_operations;
+
+	set_default_inode_attr(inode, sd->s_mode);
+	sysfs_refresh_inode(sd, inode);
+
+	/* initialize inode according to type */
+	switch (sysfs_type(sd)) {
+	case SYSFS_DIR:
+		inode->i_op = &sysfs_dir_inode_operations;
+		inode->i_fop = &sysfs_dir_operations;
+		break;
+	case SYSFS_KOBJ_ATTR:
+		inode->i_size = PAGE_SIZE;
+		inode->i_fop = &sysfs_file_operations;
+		break;
+	case SYSFS_KOBJ_BIN_ATTR:
+		bin_attr = sd->s_bin_attr.bin_attr;
+		inode->i_size = bin_attr->size;
+		inode->i_fop = &bin_fops;
+		break;
+	case SYSFS_KOBJ_LINK:
+		inode->i_op = &sysfs_symlink_inode_operations;
+		break;
+	default:
+		BUG();
+	}
+
+	unlock_new_inode(inode);
+}
+
+/**
+ *	sysfs_get_inode - get inode for sysfs_dirent
+ *	@sb: super block
+ *	@sd: sysfs_dirent to allocate inode for
+ *
+ *	Get inode for @sd.  If such inode doesn't exist, a new inode
+ *	is allocated and basics are initialized.  New inode is
+ *	returned locked.
+ *
+ *	LOCKING:
+ *	Kernel thread context (may sleep).
+ *
+ *	RETURNS:
+ *	Pointer to allocated inode on success, NULL on failure.
+ */
+struct inode * sysfs_get_inode(struct super_block *sb, struct sysfs_dirent *sd)
+{
+	struct inode *inode;
+
+	inode = iget_locked(sb, sd->s_ino);
+	if (inode && (inode->i_state & I_NEW))
+		sysfs_init_inode(sd, inode);
+
+	return inode;
+}
+
+/*
+ * The sysfs_dirent serves as both an inode and a directory entry for sysfs.
+ * To prevent the sysfs inode numbers from being freed prematurely we take a
+ * reference to sysfs_dirent from the sysfs inode.  A
+ * super_operations.evict_inode() implementation is needed to drop that
+ * reference upon inode destruction.
+ */
+void sysfs_evict_inode(struct inode *inode)
+{
+	struct sysfs_dirent *sd  = inode->i_private;
+
+	truncate_inode_pages(&inode->i_data, 0);
+	end_writeback(inode);
+	sysfs_put(sd);
+}
+
+int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const void *ns, const char *name)
+{
+	struct sysfs_addrm_cxt acxt;
+	struct sysfs_dirent *sd;
+
+	if (!dir_sd) {
+		WARN(1, KERN_WARNING "sysfs: can not remove '%s', no directory\n",
+			name);
+		return -ENOENT;
+	}
+
+	sysfs_addrm_start(&acxt, dir_sd);
+
+	sd = sysfs_find_dirent(dir_sd, ns, name);
+	if (sd)
+		sysfs_remove_one(&acxt, sd);
+
+	sysfs_addrm_finish(&acxt);
+
+	if (sd)
+		return 0;
+	else
+		return -ENOENT;
+}
+
+int sysfs_permission(struct inode *inode, int mask)
+{
+	struct sysfs_dirent *sd;
+
+	if (mask & MAY_NOT_BLOCK)
+		return -ECHILD;
+
+	sd = inode->i_private;
+
+	mutex_lock(&sysfs_mutex);
+	sysfs_refresh_inode(sd, inode);
+	mutex_unlock(&sysfs_mutex);
+
+	return generic_permission(inode, mask);
+}