patch-2.2.7 linux/fs/ncpfs/symlink.c

• Lines: 213
• Date: Tue Apr 20 15:17:20 1999
• Orig file: v2.2.6/linux/fs/ncpfs/symlink.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.2.6/linux/fs/ncpfs/symlink.c linux/fs/ncpfs/symlink.c
@@ -0,0 +1,212 @@
+/*
+ *  linux/fs/ncpfs/symlink.c
+ *
+ *  Code for allowing symbolic links on NCPFS (i.e. NetWare)
+ *  Symbolic links are not supported on native NetWare, so we use an
+ *  infrequently-used flag (Sh) and store a two-word magic header in
+ *  the file to make sure we don't accidentally use a non-link file
+ *  as a link.
+ *
+ *  from linux/fs/ext2/symlink.c
+ *
+ *  Copyright (C) 1998-99, Frank A. Vorstenbosch
+ *
+ *  ncpfs symlink handling code
+ *  NLS support (c) 1999 Petr Vandrovec
+ *
+ */
+
+#include <linux/config.h>
+
+#ifdef CONFIG_NCPFS_EXTRAS
+
+#include <asm/uaccess.h>
+#include <asm/segment.h>
+
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/ncp_fs.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/stat.h>
+#include "ncplib_kernel.h"
+
+
+/* these magic numbers must appear in the symlink file -- this makes it a bit
+   more resilient against the magic attributes being set on random files. */
+
+#define NCP_SYMLINK_MAGIC0	le32_to_cpu(0x6c6d7973)     /* "symlnk->" */
+#define NCP_SYMLINK_MAGIC1	le32_to_cpu(0x3e2d6b6e)
+
+static int ncp_readlink(struct dentry *, char *, int);
+static struct dentry *ncp_follow_link(struct dentry *, struct dentry *, unsigned int);
+int ncp_create_new(struct inode *dir, struct dentry *dentry,
+                          int mode,int attributes);
+
+/*
+ * symlinks can't do much...
+ */
+struct inode_operations ncp_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 */
+	ncp_readlink,		/* readlink */
+	ncp_follow_link,	/* follow_link */
+	NULL,			/* readpage */
+	NULL,			/* writepage */
+	NULL,			/* bmap */
+	NULL,			/* truncate */
+	NULL,			/* permission */
+	NULL			/* smap */
+};
+
+/* ----- follow a symbolic link ------------------------------------------ */
+
+static struct dentry *ncp_follow_link(struct dentry *dentry,
+				      struct dentry *base,
+				      unsigned int follow)
+{
+	struct inode *inode=dentry->d_inode;
+	int error, length, cnt;
+	char *link;
+
+#ifdef DEBUG
+	printk("ncp_follow_link(dentry=%p,base=%p,follow=%u)\n",dentry,base,follow);
+#endif
+
+	if(!S_ISLNK(inode->i_mode)) {
+		dput(base);
+		return ERR_PTR(-EINVAL);
+	}
+
+	if(ncp_make_open(inode,O_RDONLY)) {
+		dput(base);
+		return ERR_PTR(-EIO);
+	}
+
+	for (cnt = 0; (link=(char *)kmalloc(NCP_MAX_SYMLINK_SIZE+1, GFP_NFS))==NULL; cnt++) {
+		if (cnt > 10) {
+			dput(base);
+			return ERR_PTR(-EAGAIN); /* -ENOMEM? */
+		}
+		schedule();
+	}
+
+	error=ncp_read_kernel(NCP_SERVER(inode),NCP_FINFO(inode)->file_handle,
+                         0,NCP_MAX_SYMLINK_SIZE,link,&length);
+
+	if (error!=0 || length<NCP_MIN_SYMLINK_SIZE || 
+	   ((__u32 *)link)[0]!=NCP_SYMLINK_MAGIC0 || ((__u32 *)link)[1]!=NCP_SYMLINK_MAGIC1) {
+		dput(base);
+		kfree(link);
+		return ERR_PTR(-EIO);
+	}
+ 
+	link[length]=0;
+
+	vol2io(NCP_SERVER(inode), link+8, 0);
+	
+	/* UPDATE_ATIME(inode); */
+	base=lookup_dentry(link+8, base, follow);
+	kfree(link);
+
+	return base;
+}
+
+/* ----- read symbolic link ---------------------------------------------- */
+
+static int ncp_readlink(struct dentry * dentry, char * buffer, int buflen)
+{
+	struct inode *inode=dentry->d_inode;
+	char *link;
+	int length,error;
+
+#ifdef DEBUG
+	printk("ncp_readlink(dentry=%p,buffer=%p,buflen=%d)\n",dentry,buffer,buflen);
+#endif
+
+	if(!S_ISLNK(inode->i_mode))
+		return -EINVAL;
+
+	if(ncp_make_open(inode,O_RDONLY))
+		return -EIO;
+
+	if((link=(char *)kmalloc(NCP_MAX_SYMLINK_SIZE+1,GFP_NFS))==NULL)
+		return -ENOMEM;
+
+	error = ncp_read_kernel(NCP_SERVER(inode),NCP_FINFO(inode)->file_handle,
+		0,NCP_MAX_SYMLINK_SIZE,link,&length);
+
+	if (error!=0 || length < NCP_MIN_SYMLINK_SIZE || buflen < (length-8) ||
+	   ((__u32 *)link)[0]!=NCP_SYMLINK_MAGIC0 ||((__u32 *)link)[1]!=NCP_SYMLINK_MAGIC1) {
+	   	error = -EIO;
+		goto out;
+	}
+
+	link[length] = 0;
+
+	vol2io(NCP_SERVER(inode), link+8, 0);
+	
+	error = length - 8;
+	if(copy_to_user(buffer, link+8, error))
+		error = -EFAULT;
+      
+out:;
+	kfree(link);
+	return error;
+}
+
+/* ----- create a new symbolic link -------------------------------------- */
+ 
+int ncp_symlink(struct inode *dir, struct dentry *dentry, const char *symname) {
+	int i,length;
+	struct inode *inode;
+	char *link;
+
+#ifdef DEBUG
+	printk("ncp_symlink(dir=%p,dentry=%p,symname=%s)\n",dir,dentry,symname);
+#endif
+
+	if (!(NCP_SERVER(dir)->m.flags & NCP_MOUNT_SYMLINKS))
+		return -EPERM;	/* EPERM is returned by VFS if symlink procedure does not exist */
+
+	if ((length=strlen(symname))>NCP_MAX_SYMLINK_SIZE)
+		return -EINVAL;
+
+	if ((link=(char *)kmalloc(length+9,GFP_NFS))==NULL)
+		return -ENOMEM;
+
+	if (ncp_create_new(dir,dentry,0,aSHARED|aHIDDEN)) {
+		kfree(link);
+		return -EIO;
+	}
+
+	inode=dentry->d_inode;
+
+	((__u32 *)link)[0]=NCP_SYMLINK_MAGIC0;
+	((__u32 *)link)[1]=NCP_SYMLINK_MAGIC1;
+	memcpy(link+8, symname, length+1); /* including last zero for io2vol */
+
+	/* map to/from server charset, do not touch upper/lower case as
+	   symlink can point out of ncp filesystem */
+	io2vol(NCP_SERVER(inode), link+8, 0);
+	
+	if(ncp_write_kernel(NCP_SERVER(inode), NCP_FINFO(inode)->file_handle, 
+	    		    0, length+8, link, &i) || i!=length+8) {
+		kfree(link);
+		return -EIO;
+	}
+
+	kfree(link);
+	return 0;
+}
+#endif
+
+/* ----- EOF ----- */