smb_putmsghdr() now supports expanding message headers beyond allocated blocks

The old "illegal header length increase" error goes away and now
smb_putmsghdr() will re-allocate a header if needs to be moved to accommodate
new header fields or header fields with increase data lengths.

We can consider getting rid of the MsgBase "expand_fields" concept now.

This fixes issue #404

src/smblib/smballoc.c

@@ -299,6 +299,9 @@ int smb_freemsghdr(smb_t* smb, off_t offset, uint length)
 	int		l,blocks;
 	off_t	sha_offset;
 
+	if(smb->status.attr&SMB_HYPERALLOC)  /* Nothing to do */
+		return(SMB_SUCCESS);
+
 	if(smb->sha_fp==NULL) {
 		safe_snprintf(smb->last_error, sizeof(smb->last_error), "%s msgbase not open", __FUNCTION__);
 		return(SMB_ERR_NOT_OPEN);

src/smblib/smblib.c

@@ -1597,6 +1597,10 @@ int smb_addcrc(smb_t* smb, uint32_t crc)
 /* This function will UN-lock the SMB header								*/
 /****************************************************************************/
 int smb_addmsghdr(smb_t* smb, smbmsg_t* msg, int storage)
+{
+	return smb_new_msghdr(smb, msg, storage, /* new_msg: */TRUE);
+}
+int smb_new_msghdr(smb_t* smb, smbmsg_t* msg, int storage, BOOL new_msg)
 {
 	int		i;
 	off_t	l;
@@ -1635,6 +1639,7 @@ int smb_addmsghdr(smb_t* smb, smbmsg_t* msg, int storage)
 		return SMB_ERR_FILE_LEN;
 	}
 
+	if(new_msg) {
 		msg->hdr.number=smb->status.last_msg+1;
 
 		if(msg->hdr.thread_id==0)	/* new thread being started */
@@ -1646,7 +1651,7 @@ int smb_addmsghdr(smb_t* smb, smbmsg_t* msg, int storage)
 			smb_unlocksmbhdr(smb);
 			return(i);	/* error updating hash table */
 		}
-
+	}
 	if(storage!=SMB_HYPERALLOC && (i=smb_open_ha(smb))!=SMB_SUCCESS) {
 		smb_unlocksmbhdr(smb);
 		return(i);
@@ -1669,10 +1674,11 @@ int smb_addmsghdr(smb_t* smb, smbmsg_t* msg, int storage)
 	}
 
 	msg->idx.offset=(uint32_t)(smb->status.header_offset + l);
+	if(new_msg)
 		msg->idx_offset=smb->status.total_msgs;
 	msg->hdr.attr &= ~MSG_DELETE;
 	i=smb_putmsg(smb,msg);
-	if(i==SMB_SUCCESS) {
+	if(i==SMB_SUCCESS && new_msg) {
 		smb->status.last_msg++;
 		smb->status.total_msgs++;
 		smb_putstatus(smb);
@@ -1916,11 +1922,23 @@ int smb_putmsghdr(smb_t* smb, smbmsg_t* msg)
 		return(SMB_ERR_HDR_LEN);
 	}
 	if(smb_hdrblocks(hdrlen) > smb_hdrblocks(msg->hdr.length)) {
+		off_t offset = msg->idx.offset;
+		int result = smb_new_msghdr(smb, msg, (smb->status.attr&SMB_HYPERALLOC) ? SMB_HYPERALLOC : SMB_SELFPACK, FALSE);
+		if(result != SMB_SUCCESS)
+			return result;
+		if(fseeko(smb->shd_fp, offset, SEEK_SET) != 0) {
 			safe_snprintf(smb->last_error,sizeof(smb->last_error)
-			,"%s illegal header length increase: %u (%u blocks, %hu hfields, %hu dfields) vs %hu (%u blocks)", __FUNCTION__
-			,hdrlen, smb_hdrblocks(hdrlen), msg->total_hfields, msg->hdr.total_dfields
-			,msg->hdr.length, smb_hdrblocks(msg->hdr.length));
-		return(SMB_ERR_HDR_LEN);
+				,"%s %d '%s' seeking to %u in header file (to delete)", __FUNCTION__
+				,get_errno(),STRERROR(get_errno()), (uint)msg->idx.offset);
+			return(SMB_ERR_SEEK);
+		}
+		msg->hdr.attr |= MSG_DELETE;
+		if(fwrite(&msg->hdr, sizeof(msg->hdr), 1, smb->shd_fp) != 1) {
+			safe_snprintf(smb->last_error,sizeof(smb->last_error)
+				,"%s writing fixed portion of header record (to delete)", __FUNCTION__);
+			return(SMB_ERR_WRITE);
+		}
+		return smb_freemsghdr(smb, msg->idx.offset-smb->status.header_offset, msg->hdr.length);
 	}
 	msg->hdr.length=(uint16_t)hdrlen; /* store the actual header length */
 	/**********************************/

src/smblib/smblib.h

@@ -151,6 +151,7 @@ SMBEXPORT int 		smb_dfield(smbmsg_t*, uint16_t type, uint length);
 SMBEXPORT void*		smb_get_hfield(smbmsg_t*, uint16_t type, hfield_t** hfield);
 SMBEXPORT int		smb_new_hfield(smbmsg_t*, uint16_t type, size_t, void* data);
 SMBEXPORT int		smb_new_hfield_str(smbmsg_t*, uint16_t type, const char*);
+SMBEXPORT int 		smb_new_msghdr(smb_t*, smbmsg_t*, int storage, BOOL new_msg);
 SMBEXPORT int 		smb_addmsghdr(smb_t*, smbmsg_t*, int storage);
 SMBEXPORT int 		smb_putmsg(smb_t*, smbmsg_t*);
 SMBEXPORT int 		smb_putmsgidx(smb_t*, smbmsg_t*);