[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/fs/sysfs/symlink.c b/ap/os/linux/linux-3.4.x/fs/sysfs/symlink.c
new file mode 100644
index 0000000..a7ac78f
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/fs/sysfs/symlink.c
@@ -0,0 +1,307 @@
+/*
+ * fs/sysfs/symlink.c - sysfs symlink implementation
+ *
+ * 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.
+ */
+
+#include <linux/fs.h>
+#include <linux/gfp.h>
+#include <linux/mount.h>
+#include <linux/module.h>
+#include <linux/kobject.h>
+#include <linux/namei.h>
+#include <linux/mutex.h>
+#include <linux/security.h>
+
+#include "sysfs.h"
+
+static int sysfs_do_create_link(struct kobject *kobj, struct kobject *target,
+ const char *name, int warn)
+{
+ struct sysfs_dirent *parent_sd = NULL;
+ struct sysfs_dirent *target_sd = NULL;
+ struct sysfs_dirent *sd = NULL;
+ struct sysfs_addrm_cxt acxt;
+ enum kobj_ns_type ns_type;
+ int error;
+
+ BUG_ON(!name);
+
+ if (!kobj)
+ parent_sd = &sysfs_root;
+ else
+ parent_sd = kobj->sd;
+
+ error = -EFAULT;
+ if (!parent_sd)
+ goto out_put;
+
+ /* target->sd can go away beneath us but is protected with
+ * sysfs_assoc_lock. Fetch target_sd from it.
+ */
+ spin_lock(&sysfs_assoc_lock);
+ if (target->sd)
+ target_sd = sysfs_get(target->sd);
+ spin_unlock(&sysfs_assoc_lock);
+
+ error = -ENOENT;
+ if (!target_sd)
+ goto out_put;
+
+ error = -ENOMEM;
+ sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK);
+ if (!sd)
+ goto out_put;
+
+ ns_type = sysfs_ns_type(parent_sd);
+ if (ns_type)
+ sd->s_ns = target->ktype->namespace(target);
+ sd->s_symlink.target_sd = target_sd;
+ target_sd = NULL; /* reference is now owned by the symlink */
+
+ sysfs_addrm_start(&acxt, parent_sd);
+ /* Symlinks must be between directories with the same ns_type */
+ if (!ns_type ||
+ (ns_type == sysfs_ns_type(sd->s_symlink.target_sd->s_parent))) {
+ if (warn)
+ error = sysfs_add_one(&acxt, sd);
+ else
+ error = __sysfs_add_one(&acxt, sd);
+ } else {
+ error = -EINVAL;
+ WARN(1, KERN_WARNING
+ "sysfs: symlink across ns_types %s/%s -> %s/%s\n",
+ parent_sd->s_name,
+ sd->s_name,
+ sd->s_symlink.target_sd->s_parent->s_name,
+ sd->s_symlink.target_sd->s_name);
+ }
+ sysfs_addrm_finish(&acxt);
+
+ if (error)
+ goto out_put;
+
+ return 0;
+
+ out_put:
+ sysfs_put(target_sd);
+ sysfs_put(sd);
+ return error;
+}
+
+/**
+ * sysfs_create_link - create symlink between two objects.
+ * @kobj: object whose directory we're creating the link in.
+ * @target: object we're pointing to.
+ * @name: name of the symlink.
+ */
+int sysfs_create_link(struct kobject *kobj, struct kobject *target,
+ const char *name)
+{
+ return sysfs_do_create_link(kobj, target, name, 1);
+}
+
+/**
+ * sysfs_create_link_nowarn - create symlink between two objects.
+ * @kobj: object whose directory we're creating the link in.
+ * @target: object we're pointing to.
+ * @name: name of the symlink.
+ *
+ * This function does the same as sysf_create_link(), but it
+ * doesn't warn if the link already exists.
+ */
+int sysfs_create_link_nowarn(struct kobject *kobj, struct kobject *target,
+ const char *name)
+{
+ return sysfs_do_create_link(kobj, target, name, 0);
+}
+
+/**
+ * sysfs_delete_link - remove symlink in object's directory.
+ * @kobj: object we're acting for.
+ * @targ: object we're pointing to.
+ * @name: name of the symlink to remove.
+ *
+ * Unlike sysfs_remove_link sysfs_delete_link has enough information
+ * to successfully delete symlinks in tagged directories.
+ */
+void sysfs_delete_link(struct kobject *kobj, struct kobject *targ,
+ const char *name)
+{
+ const void *ns = NULL;
+ spin_lock(&sysfs_assoc_lock);
+ if (targ->sd && sysfs_ns_type(kobj->sd))
+ ns = targ->sd->s_ns;
+ spin_unlock(&sysfs_assoc_lock);
+ sysfs_hash_and_remove(kobj->sd, ns, name);
+}
+
+/**
+ * sysfs_remove_link - remove symlink in object's directory.
+ * @kobj: object we're acting for.
+ * @name: name of the symlink to remove.
+ */
+
+void sysfs_remove_link(struct kobject * kobj, const char * name)
+{
+ struct sysfs_dirent *parent_sd = NULL;
+
+ if (!kobj)
+ parent_sd = &sysfs_root;
+ else
+ parent_sd = kobj->sd;
+
+ sysfs_hash_and_remove(parent_sd, NULL, name);
+}
+
+/**
+ * sysfs_rename_link - rename symlink in object's directory.
+ * @kobj: object we're acting for.
+ * @targ: object we're pointing to.
+ * @old: previous name of the symlink.
+ * @new: new name of the symlink.
+ *
+ * A helper function for the common rename symlink idiom.
+ */
+int sysfs_rename_link(struct kobject *kobj, struct kobject *targ,
+ const char *old, const char *new)
+{
+ struct sysfs_dirent *parent_sd, *sd = NULL;
+ const void *old_ns = NULL, *new_ns = NULL;
+ int result;
+
+ if (!kobj)
+ parent_sd = &sysfs_root;
+ else
+ parent_sd = kobj->sd;
+
+ if (targ->sd)
+ old_ns = targ->sd->s_ns;
+
+ result = -ENOENT;
+ sd = sysfs_get_dirent(parent_sd, old_ns, old);
+ if (!sd)
+ goto out;
+
+ result = -EINVAL;
+ if (sysfs_type(sd) != SYSFS_KOBJ_LINK)
+ goto out;
+ if (sd->s_symlink.target_sd->s_dir.kobj != targ)
+ goto out;
+
+ if (sysfs_ns_type(parent_sd))
+ new_ns = targ->ktype->namespace(targ);
+
+ result = sysfs_rename(sd, parent_sd, new_ns, new);
+
+out:
+ sysfs_put(sd);
+ return result;
+}
+
+static int sysfs_get_target_path(struct sysfs_dirent *parent_sd,
+ struct sysfs_dirent *target_sd, char *path)
+{
+ struct sysfs_dirent *base, *sd;
+ char *s = path;
+ int len = 0;
+
+ /* go up to the root, stop at the base */
+ base = parent_sd;
+ while (base->s_parent) {
+ sd = target_sd->s_parent;
+ while (sd->s_parent && base != sd)
+ sd = sd->s_parent;
+
+ if (base == sd)
+ break;
+
+ strcpy(s, "../");
+ s += 3;
+ base = base->s_parent;
+ }
+
+ /* determine end of target string for reverse fillup */
+ sd = target_sd;
+ while (sd->s_parent && sd != base) {
+ len += strlen(sd->s_name) + 1;
+ sd = sd->s_parent;
+ }
+
+ /* check limits */
+ if (len < 2)
+ return -EINVAL;
+ len--;
+ if ((s - path) + len > PATH_MAX)
+ return -ENAMETOOLONG;
+
+ /* reverse fillup of target string from target to base */
+ sd = target_sd;
+ while (sd->s_parent && sd != base) {
+ int slen = strlen(sd->s_name);
+
+ len -= slen;
+ strncpy(s + len, sd->s_name, slen);
+ if (len)
+ s[--len] = '/';
+
+ sd = sd->s_parent;
+ }
+
+ return 0;
+}
+
+static int sysfs_getlink(struct dentry *dentry, char * path)
+{
+ struct sysfs_dirent *sd = dentry->d_fsdata;
+ struct sysfs_dirent *parent_sd = sd->s_parent;
+ struct sysfs_dirent *target_sd = sd->s_symlink.target_sd;
+ int error;
+
+ mutex_lock(&sysfs_mutex);
+ error = sysfs_get_target_path(parent_sd, target_sd, path);
+ mutex_unlock(&sysfs_mutex);
+
+ return error;
+}
+
+static void *sysfs_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+ int error = -ENOMEM;
+ unsigned long page = get_zeroed_page(GFP_KERNEL);
+ if (page) {
+ error = sysfs_getlink(dentry, (char *) page);
+ if (error < 0)
+ free_page((unsigned long)page);
+ }
+ nd_set_link(nd, error ? ERR_PTR(error) : (char *)page);
+ return NULL;
+}
+
+static void sysfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
+{
+ char *page = nd_get_link(nd);
+ if (!IS_ERR(page))
+ free_page((unsigned long)page);
+}
+
+const struct inode_operations sysfs_symlink_inode_operations = {
+ .setxattr = sysfs_setxattr,
+ .readlink = generic_readlink,
+ .follow_link = sysfs_follow_link,
+ .put_link = sysfs_put_link,
+ .setattr = sysfs_setattr,
+ .getattr = sysfs_getattr,
+ .permission = sysfs_permission,
+};
+
+
+EXPORT_SYMBOL_GPL(sysfs_create_link);
+EXPORT_SYMBOL_GPL(sysfs_remove_link);
+EXPORT_SYMBOL_GPL(sysfs_rename_link);