patch-2.3.17 linux/fs/udf/symlink.c

• Lines: 190
• Date: Sat Sep 4 12:42:30 1999
• Orig file: v2.3.16/linux/fs/udf/symlink.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.16/linux/fs/udf/symlink.c linux/fs/udf/symlink.c
@@ -0,0 +1,189 @@
+/*
+ * symlink.c
+ *
+ * PURPOSE
+ *	Symlink handling routines for the OSTA-UDF(tm) filesystem.
+ *
+ * CONTACTS
+ *	E-mail regarding any portion of the Linux UDF file system should be
+ *	directed to the development team mailing list (run by majordomo):
+ *		linux_udf@hootie.lvld.hp.com
+ *
+ * COPYRIGHT
+ *	This file is distributed under the terms of the GNU General Public
+ *	License (GPL). Copies of the GPL can be obtained from:
+ *		ftp://prep.ai.mit.edu/pub/gnu/GPL
+ *	Each contributing author retains all rights to their own work.
+ *
+ *  (C) 1998-1999 Ben Fennema
+ *  (C) 1999 Stelias Computing Inc 
+ *
+ * HISTORY
+ *
+ *  04/16/99 blf  Created.
+ *
+ */
+
+#include "udfdecl.h"
+#include <asm/uaccess.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/udf_fs.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/stat.h>
+#include <linux/malloc.h>
+#include "udf_i.h"
+
+static int udf_readlink(struct dentry *, char *, int);
+static struct dentry * udf_follow_link(struct dentry * dentry,
+	struct dentry * base, unsigned int follow);
+
+/*
+ * symlinks can't do much...
+ */
+struct inode_operations udf_symlink_inode_operations = {
+    NULL,			/* no file-operations */
+    NULL,			/* create */
+    NULL,			/* lookup */
+    NULL,			/* link */
+    NULL,			/* unlink */
+    NULL,			/* symlink */
+    NULL,			/* mkdir */
+    NULL,			/* rmdir */
+    NULL,			/* mknod */
+    NULL,			/* rename */
+    udf_readlink,	/* readlink */
+    udf_follow_link,/* follow_link */
+	NULL,			/* get_block */
+    NULL,			/* readpage */
+    NULL,			/* writepage */
+	NULL,			/* flushpage */
+    NULL,			/* truncate */
+    NULL,			/* permission */
+    NULL,			/* smap */
+	NULL			/* revalidate */
+};
+
+int udf_pc_to_char(char *from, int fromlen, char **to)
+{
+	struct PathComponent *pc;
+	int elen = 0, len = 0;
+
+	*to = (char *)kmalloc(fromlen, GFP_KERNEL);
+
+	if (!(*to))
+		return -1;
+
+	while (elen < fromlen)
+	{
+		pc = (struct PathComponent *)(from + elen);
+		if (pc->componentType == 1 && pc->lengthComponentIdent == 0)
+		{
+			(*to)[0] = '/';
+			len = 1;
+		}
+		else if (pc->componentType == 3)
+		{
+			memcpy(&(*to)[len], "../", 3);
+			len += 3;
+		}
+        else if (pc->componentType == 4)
+		{
+			memcpy(&(*to)[len], "./", 2);
+			len += 2;
+		}
+		else if (pc->componentType == 5)
+		{
+			memcpy(&(*to)[len], pc->componentIdent, pc->lengthComponentIdent);
+			len += pc->lengthComponentIdent + 1;
+			(*to)[len-1] = '/';
+		}
+		elen += sizeof(struct PathComponent) + pc->lengthComponentIdent;
+	}
+
+	if (len)
+	{
+		len --;
+		(*to)[len] = '\0';
+	}
+	return len;
+}
+
+static struct dentry * udf_follow_link(struct dentry * dentry,
+	struct dentry * base, unsigned int follow)
+{
+	struct inode *inode = dentry->d_inode;
+	struct buffer_head *bh = NULL;
+	char *symlink, *tmpbuf;
+	int len;
+	
+	if (UDF_I_ALLOCTYPE(inode) == ICB_FLAG_AD_IN_ICB)
+	{
+		bh = udf_tread(inode->i_sb, inode->i_ino, inode->i_sb->s_blocksize);
+
+		if (!bh)
+			return 0;
+
+		symlink = bh->b_data + udf_file_entry_alloc_offset(inode);
+	}
+	else
+	{
+		bh = bread(inode->i_dev, udf_block_map(inode, 0), inode->i_sb->s_blocksize);
+
+		if (!bh)
+			return 0;
+
+		symlink = bh->b_data;
+	}
+
+	if ((len = udf_pc_to_char(symlink, inode->i_size, &tmpbuf)) >= 0)
+	{
+		base = lookup_dentry(tmpbuf, base, follow);
+		kfree(tmpbuf);
+		return base;
+	}
+	else
+		return ERR_PTR(-ENOMEM);
+}
+
+static int udf_readlink(struct dentry * dentry, char * buffer, int buflen)
+{
+	struct inode *inode = dentry->d_inode;
+	struct buffer_head *bh = NULL;
+	char *symlink, *tmpbuf;
+	int len;
+	
+	if (UDF_I_ALLOCTYPE(inode) == ICB_FLAG_AD_IN_ICB)
+	{
+		bh = udf_tread(inode->i_sb, inode->i_ino, inode->i_sb->s_blocksize);
+
+		if (!bh)
+			return 0;
+
+		symlink = bh->b_data + udf_file_entry_alloc_offset(inode);
+	}
+	else
+	{
+		bh = bread(inode->i_dev, udf_block_map(inode, 0), inode->i_sb->s_blocksize);
+
+		if (!bh)
+			return 0;
+
+		symlink = bh->b_data;
+	}
+
+	if ((len = udf_pc_to_char(symlink, inode->i_size, &tmpbuf)) >= 0)
+	{
+		if (copy_to_user(buffer, tmpbuf, len > buflen ? buflen : len))
+			len = -EFAULT;
+		kfree(tmpbuf);
+	}
+	else
+		len = -ENOMEM;
+
+	UPDATE_ATIME(inode);
+	if (bh)
+		udf_release_data(bh);
+	return len;
+}