Fixed MTP to work with TWRP

fs/ncpfs/symlink.c

@@ -0,0 +1,181 @@
+/*
+ *  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.
+ *
+ *  When using the NFS namespace, we set the mode to indicate a symlink and
+ *  don't bother with the magic numbers.
+ *
+ *  from linux/fs/ext2/symlink.c
+ *
+ *  Copyright (C) 1998-99, Frank A. Vorstenbosch
+ *
+ *  ncpfs symlink handling code
+ *  NLS support (c) 1999 Petr Vandrovec
+ *  Modified 2000 Ben Harris, University of Cambridge for NFS NS meta-info
+ *
+ */
+
+
+#include <asm/uaccess.h>
+
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/stat.h>
+#include "ncp_fs.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	cpu_to_le32(0x6c6d7973)     /* "symlnk->" */
+#define NCP_SYMLINK_MAGIC1	cpu_to_le32(0x3e2d6b6e)
+
+/* ----- read a symbolic link ------------------------------------------ */
+
+static int ncp_symlink_readpage(struct file *file, struct page *page)
+{
+	struct inode *inode = page->mapping->host;
+	int error, length, len;
+	char *link, *rawlink;
+	char *buf = kmap(page);
+
+	error = -ENOMEM;
+	rawlink = kmalloc(NCP_MAX_SYMLINK_SIZE, GFP_KERNEL);
+	if (!rawlink)
+		goto fail;
+
+	if (ncp_make_open(inode,O_RDONLY))
+		goto failEIO;
+
+	error=ncp_read_kernel(NCP_SERVER(inode),NCP_FINFO(inode)->file_handle,
+                         0,NCP_MAX_SYMLINK_SIZE,rawlink,&length);
+
+	ncp_inode_close(inode);
+	/* Close file handle if no other users... */
+	ncp_make_closed(inode);
+	if (error)
+		goto failEIO;
+
+	if (NCP_FINFO(inode)->flags & NCPI_KLUDGE_SYMLINK) {
+		if (length<NCP_MIN_SYMLINK_SIZE || 
+		    ((__le32 *)rawlink)[0]!=NCP_SYMLINK_MAGIC0 ||
+		    ((__le32 *)rawlink)[1]!=NCP_SYMLINK_MAGIC1)
+		    	goto failEIO;
+		link = rawlink + 8;
+		length -= 8;
+	} else {
+		link = rawlink;
+	}
+
+	len = NCP_MAX_SYMLINK_SIZE;
+	error = ncp_vol2io(NCP_SERVER(inode), buf, &len, link, length, 0);
+	kfree(rawlink);
+	if (error)
+		goto fail;
+	SetPageUptodate(page);
+	kunmap(page);
+	unlock_page(page);
+	return 0;
+
+failEIO:
+	error = -EIO;
+	kfree(rawlink);
+fail:
+	SetPageError(page);
+	kunmap(page);
+	unlock_page(page);
+	return error;
+}
+
+/*
+ * symlinks can't do much...
+ */
+const struct address_space_operations ncp_symlink_aops = {
+	.readpage	= ncp_symlink_readpage,
+};
+	
+/* ----- create a new symbolic link -------------------------------------- */
+ 
+int ncp_symlink(struct inode *dir, struct dentry *dentry, const char *symname) {
+	struct inode *inode;
+	char *rawlink;
+	int length, err, i, outlen;
+	int kludge;
+	umode_t mode;
+	__le32 attr;
+	unsigned int hdr;
+
+	ncp_dbg(1, "dir=%p, dentry=%p, symname=%s\n", dir, dentry, symname);
+
+	if (ncp_is_nfs_extras(NCP_SERVER(dir), NCP_FINFO(dir)->volNumber))
+		kludge = 0;
+	else
+#ifdef CONFIG_NCPFS_EXTRAS
+	if (NCP_SERVER(dir)->m.flags & NCP_MOUNT_SYMLINKS)
+		kludge = 1;
+	else
+#endif
+	/* EPERM is returned by VFS if symlink procedure does not exist */
+		return -EPERM;
+  
+	rawlink = kmalloc(NCP_MAX_SYMLINK_SIZE, GFP_KERNEL);
+	if (!rawlink)
+		return -ENOMEM;
+
+	if (kludge) {
+		mode = 0;
+		attr = aSHARED | aHIDDEN;
+		((__le32 *)rawlink)[0]=NCP_SYMLINK_MAGIC0;
+		((__le32 *)rawlink)[1]=NCP_SYMLINK_MAGIC1;
+		hdr = 8;
+	} else {
+		mode = S_IFLNK | S_IRWXUGO;
+		attr = 0;
+		hdr = 0;
+	}			
+
+	length = strlen(symname);
+	/* map to/from server charset, do not touch upper/lower case as
+	   symlink can point out of ncp filesystem */
+	outlen = NCP_MAX_SYMLINK_SIZE - hdr;
+	err = ncp_io2vol(NCP_SERVER(dir), rawlink + hdr, &outlen, symname, length, 0);
+	if (err)
+		goto failfree;
+
+	outlen += hdr;
+
+	err = -EIO;
+	if (ncp_create_new(dir,dentry,mode,0,attr)) {
+		goto failfree;
+	}
+
+	inode=dentry->d_inode;
+
+	if (ncp_make_open(inode, O_WRONLY))
+		goto failfree;
+
+	if (ncp_write_kernel(NCP_SERVER(inode), NCP_FINFO(inode)->file_handle, 
+			     0, outlen, rawlink, &i) || i!=outlen) {
+		goto fail;
+	}
+
+	ncp_inode_close(inode);
+	ncp_make_closed(inode);
+	kfree(rawlink);
+	return 0;
+fail:;
+	ncp_inode_close(inode);
+	ncp_make_closed(inode);
+failfree:;
+	kfree(rawlink);
+	return err;
+}
+
+/* ----- EOF ----- */