[CIFS] CIFS support for named pipes (part 1)

This allows cifs to mount to ipc shares (IPC$)
which will allow user space applications to
layer over authenticated cifs connections
(useful for Wine and others that would want
to put DCE/RPC over CIFS or run CIFS named
pipes)

Acked-by: Rob Shearman <rob@codeweavers.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifsglob.h

@@ -291,6 +291,7 @@ struct cifsTconInfo {
 	FILE_SYSTEM_DEVICE_INFO fsDevInfo;
 	FILE_SYSTEM_ATTRIBUTE_INFO fsAttrInfo; /* ok if fs name truncated */
 	FILE_SYSTEM_UNIX_INFO fsUnixInfo;
+	unsigned ipc:1;		/* set if connection to IPC$ eg for RPC/PIPES */
 	unsigned retry:1;
 	unsigned nocase:1;
 	unsigned unix_ext:1; /* if off disable Linux extensions to CIFS protocol
@@ -341,6 +342,7 @@ struct cifsFileInfo {
 	struct list_head llist; /* list of byte range locks we have. */
 	unsigned closePend:1;	/* file is marked to close */
 	unsigned invalidHandle:1;  /* file closed via session abend */
+	unsigned messageMode:1    /* for pipes: is message or byte mode */
 	atomic_t wrtPending;   /* handle in use - defer close */
 	struct semaphore fh_sem; /* prevents reopen race after dead ses*/
 	char *search_resume_name; /* BB removeme BB */

fs/cifs/connect.c

@@ -2186,8 +2186,10 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
 		tcon->ses = pSesInfo;
 
 		/* do not care if following two calls succeed - informational */
+		if (!tcon->ipc) {
 			CIFSSMBQFSDeviceInfo(xid, tcon);
 			CIFSSMBQFSAttributeInfo(xid, tcon);
+		}
 
 		/* tell server which Unix caps we support */
 		if (tcon->ses->capabilities & CAP_UNIX)
@@ -3385,6 +3387,18 @@ CIFSTCon(unsigned int xid, struct cifsSesInfo *ses,
 		bcc_ptr = pByteArea(smb_buffer_response);
 		length = strnlen(bcc_ptr, BCC(smb_buffer_response) - 2);
 		/* skip service field (NB: this field is always ASCII) */
+		if (length == 3) {
+			if ((bcc_ptr[0] == 'I') && (bcc_ptr[1] == 'P') &&
+			    (bcc_ptr[2] == 'C')) {
+				cFYI(1, ("IPC connection"));
+				tcon->ipc = 1;
+			}
+		} else if (length == 2) {
+			if ((bcc_ptr[0] == 'A') && (bcc_ptr[1] == ':')) {
+				/* the most common case */
+				cFYI(1, ("disk share connection"));
+			}
+		}
 		bcc_ptr += length + 1;
 		strncpy(tcon->treeName, tree, MAX_TREE_SIZE);
 		if (smb_buffer->Flags2 & SMBFLG2_UNICODE) {

fs/cifs/dir.c

@@ -3,7 +3,7 @@
  *
  *   vfs operations that deal with dentries
  *
- *   Copyright (C) International Business Machines  Corp., 2002,2005
+ *   Copyright (C) International Business Machines  Corp., 2002,2007
  *   Author(s): Steve French (sfrench@us.ibm.com)
  *
  *   This library is free software; you can redistribute it and/or modify

fs/cifs/inode.c

@@ -575,19 +575,33 @@ int cifs_get_inode_info(struct inode **pinode,
 	return rc;
 }
 
+static const struct inode_operations cifs_ipc_inode_ops = {
+	.lookup = cifs_lookup,
+};
+
 /* gets root inode */
 void cifs_read_inode(struct inode *inode)
 {
-	int xid;
+	int xid, rc;
 	struct cifs_sb_info *cifs_sb;
 
 	cifs_sb = CIFS_SB(inode->i_sb);
 	xid = GetXid();
 
 	if (cifs_sb->tcon->unix_ext)
-		cifs_get_inode_info_unix(&inode, "", inode->i_sb, xid);
+		rc = cifs_get_inode_info_unix(&inode, "", inode->i_sb, xid);
 	else
-		cifs_get_inode_info(&inode, "", NULL, inode->i_sb, xid);
+		rc = cifs_get_inode_info(&inode, "", NULL, inode->i_sb, xid);
+	if (rc && cifs_sb->tcon->ipc) {
+		cFYI(1, ("ipc connection - fake read inode"));
+		inode->i_mode |= S_IFDIR;
+		inode->i_nlink = 2;
+		inode->i_op = &cifs_ipc_inode_ops;
+		inode->i_fop = &simple_dir_operations;
+		inode->i_uid = cifs_sb->mnt_uid;
+		inode->i_gid = cifs_sb->mnt_gid;
+	}
+
 	/* can not call macro FreeXid here since in a void func */
 	_FreeXid(xid);
 }

fs/cifs/misc.c

@@ -169,7 +169,6 @@ cifs_buf_get(void)
 void
 cifs_buf_release(void *buf_to_free)
 {
-
 	if (buf_to_free == NULL) {
 		/* cFYI(1, ("Null buffer passed to cifs_buf_release"));*/
 		return;