patch-2.3.2 linux/fs/efs/symlink.c

• Lines: 103
• Date: Thu May 13 23:50:15 1999
• Orig file: v2.3.1/linux/fs/efs/symlink.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.1/linux/fs/efs/symlink.c linux/fs/efs/symlink.c
@@ -0,0 +1,102 @@
+/*
+ * symlink.c
+ *
+ * Copyright (c) 1999 Al Smith
+ *
+ * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
+ */
+
+#include <linux/malloc.h>
+#include <linux/efs_fs.h>
+
+static int efs_readlink(struct dentry *, char *, int);
+static struct dentry * efs_follow_link(struct dentry *, struct dentry *, unsigned int);
+
+struct inode_operations efs_symlink_inode_operations = {
+	NULL,			/* no symlink file-operations */
+	NULL,			/* create */
+	NULL,			/* lookup */
+	NULL,			/* link */
+	NULL,			/* unlink */
+	NULL,			/* symlink */
+	NULL,			/* mkdir */
+	NULL,			/* rmdir */
+	NULL,			/* mknod */
+	NULL,			/* rename */
+	efs_readlink,		/* readlink */
+	efs_follow_link,	/* follow_link */
+	NULL,			/* readpage */
+	NULL,			/* writepage */
+	NULL,			/* bmap */
+	NULL,			/* truncate */
+	NULL,			/* permission */
+	NULL			/* smap */
+};
+
+static char *efs_linktarget(struct inode *in, int *len) {
+	char *name;
+	struct buffer_head * bh;
+	efs_block_t size = in->i_size;
+  
+	if (size > 2 * EFS_BLOCKSIZE) {
+		printk(KERN_ERR "EFS: linktarget(): name too long: %lu\n", in->i_size);
+		return NULL;
+	}
+  
+	if (!(name = kmalloc(size + 1, GFP_KERNEL)))
+		return NULL;
+  
+	/* read first 512 bytes of link target */
+	bh = bread(in->i_dev, efs_bmap(in, 0), EFS_BLOCKSIZE);
+	if (!bh) {
+		kfree(name);
+		printk(KERN_ERR "EFS: linktarget(): couldn't read block %d\n", efs_bmap(in, 0));
+		return NULL;
+	}
+
+	memcpy(name, bh->b_data, (size > EFS_BLOCKSIZE) ? EFS_BLOCKSIZE : size);
+	brelse(bh);
+
+	if (size > EFS_BLOCKSIZE) {
+		bh = bread(in->i_dev, efs_bmap(in, 1), EFS_BLOCKSIZE);
+		if (!bh) {
+			kfree(name);
+			printk(KERN_ERR "EFS: linktarget(): couldn't read block %d\n", efs_bmap(in, 1));
+			return NULL;
+		}
+		memcpy(name + EFS_BLOCKSIZE, bh->b_data, size - EFS_BLOCKSIZE);
+		brelse(bh);
+	}
+  
+	name[size] = (char) 0;
+	if (len) *len = size;
+
+	return name;
+}
+
+static struct dentry *efs_follow_link(struct dentry *dentry, struct dentry *base, unsigned int follow) {
+	char *name;
+	struct inode *inode = dentry->d_inode;
+
+	if (!(name = efs_linktarget(inode, NULL))) {
+		dput(base);
+		return ERR_PTR(-ELOOP);
+	}
+	base = lookup_dentry(name, base, follow);
+	kfree(name);
+  
+	return base;
+}
+
+static int efs_readlink(struct dentry * dir, char * buf, int bufsiz) {
+	int rc;
+	char *name;
+	struct inode *inode = dir->d_inode;
+  
+	if (!(name = efs_linktarget(inode, &bufsiz))) return 0;
+	rc = copy_to_user(buf, name, bufsiz) ? -EFAULT : bufsiz;
+	kfree(name);
+
+	return rc;
+}
+