#include <linux/fs.h>
#include <linux/module.h>
#include <linux/kobject.h>
+#include <linux/namei.h>
#include "sysfs.h"
-
-static int init_symlink(struct inode * inode)
-{
- inode->i_op = &page_symlink_inode_operations;
- return 0;
-}
-
-static int sysfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
-{
- int error;
-
- error = sysfs_create(dentry, S_IFLNK|S_IRWXUGO, init_symlink);
- if (!error) {
- int l = strlen(symname)+1;
- error = page_symlink(dentry->d_inode, symname, l);
- if (error)
- iput(dentry->d_inode);
- }
- return error;
-}
-
static int object_depth(struct kobject * kobj)
{
struct kobject * p = kobj;
}
}
+static int sysfs_add_link(struct dentry * parent, char * name, struct kobject * target)
+{
+ struct sysfs_dirent * parent_sd = parent->d_fsdata;
+ struct sysfs_symlink * sl;
+ int error = 0;
+
+ error = -ENOMEM;
+ sl = kmalloc(sizeof(*sl), GFP_KERNEL);
+ if (!sl)
+ goto exit1;
+
+ sl->link_name = kmalloc(strlen(name) + 1, GFP_KERNEL);
+ if (!sl->link_name)
+ goto exit2;
+
+ strcpy(sl->link_name, name);
+ sl->target_kobj = kobject_get(target);
+
+ error = sysfs_make_dirent(parent_sd, NULL, sl, S_IFLNK|S_IRWXUGO,
+ SYSFS_KOBJ_LINK);
+ if (!error)
+ return 0;
+
+ kfree(sl->link_name);
+exit2:
+ kfree(sl);
+exit1:
+ return error;
+}
+
/**
* sysfs_create_link - create symlink between two objects.
* @kobj: object whose directory we're creating the link in.
int sysfs_create_link(struct kobject * kobj, struct kobject * target, char * name)
{
struct dentry * dentry = kobj->dentry;
- struct dentry * d;
int error = 0;
- int size;
- int depth;
- char * path;
- char * s;
-
- depth = object_depth(kobj);
- size = object_path_length(target) + depth * 3 - 1;
- if (size > PATH_MAX)
- return -ENAMETOOLONG;
- pr_debug("%s: depth = %d, size = %d\n",__FUNCTION__,depth,size);
-
- path = kmalloc(size,GFP_KERNEL);
- if (!path)
- return -ENOMEM;
- memset(path,0,size);
-
- for (s = path; depth--; s += 3)
- strcpy(s,"../");
- fill_object_path(target,path,size);
- pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
+ BUG_ON(!kobj || !kobj->dentry || !name);
down(&dentry->d_inode->i_sem);
- d = sysfs_get_dentry(dentry,name);
- if (!IS_ERR(d))
- error = sysfs_symlink(dentry->d_inode,d,path);
- else
- error = PTR_ERR(d);
- dput(d);
+ error = sysfs_add_link(dentry, name, target);
up(&dentry->d_inode->i_sem);
- kfree(path);
return error;
}
sysfs_hash_and_remove(kobj->dentry,name);
}
+static int sysfs_get_target_path(struct kobject * kobj, struct kobject * target,
+ char *path)
+{
+ char * s;
+ int depth, size;
+
+ depth = object_depth(kobj);
+ size = object_path_length(target) + depth * 3 - 1;
+ if (size > PATH_MAX)
+ return -ENAMETOOLONG;
+
+ pr_debug("%s: depth = %d, size = %d\n", __FUNCTION__, depth, size);
+
+ for (s = path; depth--; s += 3)
+ strcpy(s,"../");
+
+ fill_object_path(target, path, size);
+ pr_debug("%s: path = '%s'\n", __FUNCTION__, path);
+
+ return 0;
+}
+
+static int sysfs_getlink(struct dentry *dentry, char * path)
+{
+ struct kobject *kobj, *target_kobj;
+ int error = 0;
+
+ kobj = sysfs_get_kobject(dentry->d_parent);
+ if (!kobj)
+ return -EINVAL;
+
+ target_kobj = sysfs_get_kobject(dentry);
+ if (!target_kobj) {
+ kobject_put(kobj);
+ return -EINVAL;
+ }
+
+ down_read(&sysfs_rename_sem);
+ error = sysfs_get_target_path(kobj, target_kobj, path);
+ up_read(&sysfs_rename_sem);
+
+ kobject_put(kobj);
+ kobject_put(target_kobj);
+ return error;
+
+}
+
+static int 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);
+ nd_set_link(nd, error ? ERR_PTR(error) : (char *)page);
+ return 0;
+}
+
+static void sysfs_put_link(struct dentry *dentry, struct nameidata *nd)
+{
+ char *page = nd_get_link(nd);
+ if (!IS_ERR(page))
+ free_page((unsigned long)page);
+}
+
+struct inode_operations sysfs_symlink_inode_operations = {
+ .readlink = generic_readlink,
+ .follow_link = sysfs_follow_link,
+ .put_link = sysfs_put_link,
+};
+
-EXPORT_SYMBOL(sysfs_create_link);
-EXPORT_SYMBOL(sysfs_remove_link);
+EXPORT_SYMBOL_GPL(sysfs_create_link);
+EXPORT_SYMBOL_GPL(sysfs_remove_link);