X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Fsysfs%2Fsymlink.c;h=5f66c446615176eff46e1864a7343f228bac19e6;hb=877c357e7511395bc923ec9efc2e8b021a17ed79;hp=4ce687f0b5d01751dfb8f8aa189c84360eaab39e;hpb=967e35dcc9ac194b4a6fad69a5a51f93d69bb0d1;p=linux-2.6

diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 4ce687f0b5..5f66c44661 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -1,5 +1,13 @@
 /*
- * symlink.c - operations for sysfs symlinks.
+ * 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>
@@ -7,43 +15,10 @@
 #include <linux/module.h>
 #include <linux/kobject.h>
 #include <linux/namei.h>
-#include <asm/semaphore.h>
+#include <linux/mutex.h>
 
 #include "sysfs.h"
 
-static int object_depth(struct sysfs_dirent *sd)
-{
-	int depth = 0;
-
-	for (; sd->s_parent; sd = sd->s_parent)
-		depth++;
-
-	return depth;
-}
-
-static int object_path_length(struct sysfs_dirent * sd)
-{
-	int length = 1;
-
-	for (; sd->s_parent; sd = sd->s_parent)
-		length += strlen(sd->s_name) + 1;
-
-	return length;
-}
-
-static void fill_object_path(struct sysfs_dirent *sd, char *buffer, int length)
-{
-	--length;
-	for (; sd->s_parent; sd = sd->s_parent) {
-		int cur = strlen(sd->s_name);
-
-		/* back up enough to print this bus id with '/' */
-		length -= cur;
-		strncpy(buffer + length, sd->s_name, cur);
-		*(buffer + --length) = '/';
-	}
-}
-
 /**
  *	sysfs_create_link - create symlink between two objects.
  *	@kobj:	object whose directory we're creating the link in.
@@ -60,10 +35,9 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char
 
 	BUG_ON(!name);
 
-	if (!kobj) {
-		if (sysfs_mount && sysfs_mount->mnt_sb)
-			parent_sd = sysfs_mount->mnt_sb->s_root->d_fsdata;
-	} else
+	if (!kobj)
+		parent_sd = &sysfs_root;
+	else
 		parent_sd = kobj->sd;
 
 	error = -EFAULT;
@@ -87,20 +61,15 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char
 	if (!sd)
 		goto out_put;
 
-	sd->s_elem.symlink.target_sd = target_sd;
+	sd->s_symlink.target_sd = target_sd;
 	target_sd = NULL;	/* reference is now owned by the symlink */
 
 	sysfs_addrm_start(&acxt, parent_sd);
+	error = sysfs_add_one(&acxt, sd);
+	sysfs_addrm_finish(&acxt);
 
-	if (!sysfs_find_dirent(parent_sd, name)) {
-		sysfs_add_one(&acxt, sd);
-		sysfs_link_sibling(sd);
-	}
-
-	if (!sysfs_addrm_finish(&acxt)) {
-		error = -EEXIST;
+	if (error)
 		goto out_put;
-	}
 
 	return 0;
 
@@ -110,7 +79,6 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char
 	return error;
 }
 
-
 /**
  *	sysfs_remove_link - remove symlink in object's directory.
  *	@kobj:	object we're acting for.
@@ -122,24 +90,54 @@ void sysfs_remove_link(struct kobject * kobj, const char * name)
 	sysfs_hash_and_remove(kobj->sd, name);
 }
 
-static int sysfs_get_target_path(struct sysfs_dirent * parent_sd,
-				 struct sysfs_dirent * target_sd, char *path)
+static int sysfs_get_target_path(struct sysfs_dirent *parent_sd,
+				 struct sysfs_dirent *target_sd, char *path)
 {
-	char * s;
-	int depth, size;
+	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;
+	}
 
-	depth = object_depth(parent_sd);
-	size = object_path_length(target_sd) + depth * 3 - 1;
-	if (size > PATH_MAX)
+	/* 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;
 
-	pr_debug("%s: depth = %d, size = %d\n", __FUNCTION__, depth, size);
+	/* reverse fillup of target string from target to base */
+	sd = target_sd;
+	while (sd->s_parent && sd != base) {
+		int slen = strlen(sd->s_name);
 
-	for (s = path; depth--; s += 3)
-		strcpy(s,"../");
+		len -= slen;
+		strncpy(s + len, sd->s_name, slen);
+		if (len)
+			s[--len] = '/';
 
-	fill_object_path(target_sd, path, size);
-	pr_debug("%s: path = '%s'\n", __FUNCTION__, path);
+		sd = sd->s_parent;
+	}
 
 	return 0;
 }
@@ -148,7 +146,7 @@ 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_elem.symlink.target_sd;
+	struct sysfs_dirent *target_sd = sd->s_symlink.target_sd;
 	int error;
 
 	mutex_lock(&sysfs_mutex);