$NetBSD: patch-src_zmf_cpp,v 1.2 2013/03/24 16:47:47 joerg Exp $

http://www.zoneminder.com/wiki/index.php/1.24.2_Patches

Fix Incomplete Image errors in zmf

This patch changes the socket reader in zmf from a single read, to a loop
read.  Incomplete reads would be reported even though the image writer wrote
the whole image to the socket.  The problem was when the read went to read the
image frame from the socket, all the data had not yet been written to the
socket by the writer, so the reader thought there was a problem.  The loop
reads from the socket until a full image frame is read, or there is an error.

--- src/zmf.cpp.orig	2011-06-21 09:19:11.000000000 +0000
+++ src/zmf.cpp
@@ -231,16 +231,39 @@ int main( int argc, char *argv[] )
 		}
 		Debug( 1, "Read frame header, expecting %ld bytes of image", frame_header.image_length );
 		static unsigned char image_data[ZM_MAX_IMAGE_SIZE];
-		n_bytes = read( sd, image_data, frame_header.image_length );
-		if ( n_bytes != (ssize_t)frame_header.image_length )
+
+		// Read for pipe and loop until bytes expected have been read or an error occures
+		int bytes_read = 0;
+		do
 		{
-			if ( n_bytes < 0 )
+			n_bytes = read( sd, image_data+bytes_read, frame_header.image_length-bytes_read );
+			if (n_bytes < 0) break; // break on error
+			if (n_bytes < frame_header.image_length)
 			{
-				Error( "Can't read frame image data: %s", strerror(errno) );
+				// print some informational messages 
+				if (bytes_read == 0)
+				{
+					Warning("Image read : Short read %d bytes of %d expected bytes",n_bytes,frame_header.image_length);
+				}
+				else if (bytes_read+n_bytes == frame_header.image_length)
+				{
+					Warning("Image read : Read rest of short read: %d bytes read total of %d bytes",n_bytes,frame_header.image_length);
+				}
+				else
+				{
+					Warning("Image read : continuing, read %d bytes (%d so far)", n_bytes, bytes_read+n_bytes);
+				}
 			}
-			else if ( n_bytes > 0 )
+			bytes_read+= n_bytes;
+		} while (n_bytes>0 && (bytes_read < (ssize_t)frame_header.image_length) );
+
+		// Print errors if there was a problem
+		if ( n_bytes < 1 )
+		{
+			Error( "Only read %d bytes of %d\n", bytes_read, frame_header.image_length);
+			if ( n_bytes < 0 )
 			{
-				Error( "Incomplete read of frame image data, %d bytes only", n_bytes );
+				Error( "Can't read frame image data: %s", strerror(errno) );
 			}
 			else
 			{
@@ -249,16 +272,18 @@ int main( int argc, char *argv[] )
 			ReopenSocket( sd, monitor->Id() );
 			continue;
 		}
+
 		static char subpath[PATH_MAX] = "";
-        if ( config.use_deep_storage )
-        {
-            struct tm *time = localtime( &frame_header.event_time );
-            snprintf( subpath, sizeof(subpath), "%02d/%02d/%02d/%02d/%02d/%02d", time->tm_year-100, time->tm_mon+1, time->tm_mday, time->tm_hour, time->tm_min, time->tm_sec );
-        }
-        else
-        {
-            snprintf( subpath, sizeof(subpath), "%ld", frame_header.event_id );
-        }
+		if ( config.use_deep_storage )
+		{
+		    struct tm *time = localtime( &frame_header.event_time );
+		    snprintf( subpath, sizeof(subpath), "%02d/%02d/%02d/%02d/%02d/%02d", time->tm_year-100, time->tm_mon+1, time->tm_mday, time->tm_hour, time->tm_min, time->tm_sec );
+		}
+		else
+		{
+		    snprintf( subpath, sizeof(subpath), "%ld", frame_header.event_id );
+		}
+
 		static char path[PATH_MAX] = "";
 		snprintf( path, sizeof(path), frame_header.alarm_frame?anal_path:capt_path, subpath, frame_header.frame_id );
 		Debug( 1, "Got image, writing to %s", path );