patch-2_6_7-vs1_9_1_12

[linux-2.6.git] / fs / sysfs / symlink.c

diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 6216e94..c8bfec6 100644 (file)
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -8,27 +8,17 @@
 
 #include "sysfs.h"
 
+static struct inode_operations sysfs_symlink_inode_operations = {
+       .readlink = sysfs_readlink,
+       .follow_link = sysfs_follow_link,
+};
 
 static int init_symlink(struct inode * inode)
 {
-       inode->i_op = &page_symlink_inode_operations;
+       inode->i_op = &sysfs_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;
@@ -74,37 +64,20 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, char * nam
        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);
 
        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
+       if (!IS_ERR(d)) {
+               error = sysfs_create(d, S_IFLNK|S_IRWXUGO, init_symlink);
+               if (!error)
+                       /* 
+                        * associate the link dentry with the target kobject 
+                        */
+                       d->d_fsdata = kobject_get(target);
+               dput(d);
+       } else 
                error = PTR_ERR(d);
-       dput(d);
        up(&dentry->d_inode->i_sem);
-       kfree(path);
        return error;
 }
 
@@ -120,6 +93,86 @@ void sysfs_remove_link(struct kobject * kobj, char * name)
        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;
+
+}
+
+int sysfs_readlink(struct dentry *dentry, char __user *buffer, int buflen)
+{
+       int error = 0;
+       unsigned long page = get_zeroed_page(GFP_KERNEL);
+
+       if (!page)
+               return -ENOMEM;
+
+       error = sysfs_getlink(dentry, (char *) page);
+       if (!error)
+               error = vfs_readlink(dentry, buffer, buflen, (char *) page);
+
+       free_page(page);
+
+       return error;
+}
+
+int sysfs_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+       int error = 0;
+       unsigned long page = get_zeroed_page(GFP_KERNEL);
+
+       if (!page)
+               return -ENOMEM;
+
+       error = sysfs_getlink(dentry, (char *) page); 
+       if (!error)
+               error = vfs_follow_link(nd, (char *) page);
+
+       free_page(page);
+
+       return error;
+}
 
 EXPORT_SYMBOL(sysfs_create_link);
 EXPORT_SYMBOL(sysfs_remove_link);