From: Ralph Ronnquist <rrq@rrq.au>
Date: Wed, 16 Aug 2023 02:06:27 +0000 (+1000)
Subject: fixed overlay stacking bugs
X-Git-Tag: 1.2~1
X-Git-Url: https://git.rrq.au/?a=commitdiff_plain;h=9b4d0451016c061d9d2a1046a4a11f0b52fe8cf3;p=rrq%2Ffusefile.git

fixed overlay stacking bugs
---

diff --git a/fusefile.c b/fusefile.c
index ab97ff7..c8964f4 100644
--- a/fusefile.c
+++ b/fusefile.c
@@ -290,8 +290,9 @@ static void dup_source_item(int index) {
 	fprintf( stderr, "** OOM when expanding frament table\n" );
 	usage();
     }
-    memcpy( &sources.array[ index+1 ], &sources.array[ index ],
-	    sizeof( struct Source ) );
+    // copy elements from [index] to [count-1] one element down
+    size_t size = ( sources.count - index - 1 ) * sizeof( struct Source ); 
+    memmove( &sources.array[ index+1 ], &sources.array[ index ], size );
 }
 
 #if DEBUG
@@ -462,28 +463,14 @@ static int find_source(off_t offset) {
     if ( offset >= sources.size ) {
 	return -1;
     }
-#if DEBUG
-    fprintf( stderr, "find_source( %ld )\n", offset );
-#endif
     while ( lo + 1 < hi ) {
 	int m = ( lo + hi ) / 2;
 	if ( offset < sources.array[ m ].start ) {
-#if DEBUG
-	    fprintf( stderr, "  offset < [%d].start: %ld\n",
-		     m, sources.array[ m ].start );
-#endif
 	    hi = m;
 	} else {
-#if DEBUG
-	    fprintf( stderr, "  offset >= [%d].start: %ld\n",
-		     m, sources.array[ m ].start );
-#endif
 	    lo = m;
 	}
     }
-#if DEBUG
-    fprintf( stderr, "found %d\n", lo );
-#endif
     return lo;
 }
 
@@ -522,30 +509,25 @@ static int overlay_merge(char *buf,off_t beg,off_t end) {
 static int fusefile_read(const char *path, char *buf, size_t size,
 			 off_t off, struct fuse_file_info *fi)
 {
-#if DEBUG
-    fprintf( stderr, "fusefile_read( %s )\n", path );
-#endif
     if( strcmp( path, "/" ) != 0 ) {
 	return -ENOENT;
     }
-#if DEBUG
-    fprintf( stderr, "read %ld %ld\n", off, size );
-#endif
     size_t rr = 0; // total reading
-    while ( size > 0 ) {
 #if DEBUG
-	fprintf( stderr, "  find_source %ld %ld\n", off, size );
+    fprintf( stderr, "fusefile_read %ld + %ld\n", off, size );
 #endif
+    while ( size > 0 ) {
 	int i = find_source( off );
 	if ( i < 0 ) {
 	    return ( off == sources.size )? rr : -ENOENT;
 	}
+#if DEBUG
+	fprintf( stderr, " item: %d ", i );
+	print_source(& sources.array[i] );
+#endif
 	if ( sources.array[i].fd < 0 ) {
 	    return -ENOENT;
 	}
-#if DEBUG
-	print_source( &sources.array[i] );
-#endif
 	times.atime = time( 0 );
 	size_t b = off - sources.array[i].start + sources.array[i].from;
 	size_t n = sources.array[i].to - b;
@@ -556,20 +538,13 @@ static int fusefile_read(const char *path, char *buf, size_t size,
 	    fsync( sources.array[i].fd );
 	    sources.array[i].dirty = 0;
 	}
-#if DEBUG
-	fprintf( stderr, "  seek fd=%d to %ld\n", sources.array[i].fd, b );
-#endif
 	if ( lseek( sources.array[i].fd, b, SEEK_SET ) < 0 ) {
 	    perror( sources.array[i].filename );
 	    return -ENOENT;
 	}
-#if DEBUG
-	fprintf( stderr, "  now read %ld from fd=%d\n",
-		 n, sources.array[i].fd );
-#endif
 	ssize_t r = read( sources.array[i].fd, buf + rr, n );
 #if DEBUG
-	fprintf( stderr, "  got %ld bytes\n", r );
+	fprintf( stderr, " got: %ld bytes of %ld at %ld\n", r, n, rr );
 #endif
 	if ( r < 0 ) {
 	    perror( sources.array[i].filename );
@@ -657,29 +632,54 @@ static off_t overlay_inject_from_region(off_t beg,off_t end) {
     }
     struct Region frags[3] = {
 	{ sources.array[ index ].start, beg },
-	{ beg, ENDSOURCE( sources.array[ index ] ) },
-	{ ENDSOURCE( sources.array[ index ] ), end } };
+	{ beg, end },
+	{ end, ENDSOURCE( sources.array[ index ] ) } };
+#if DEBUG
+    int i;
+    for ( i = 0; i < 3; i++ ) {
+	fprintf( stderr, "frags[%d] = (%ld, %ld)\n",
+		 i, frags[i].beg, frags[i].end );
+    }
+#endif
     ssize_t size = frags[0].end - frags[0].beg;
     if ( size ) {
-	// "Duplicate" the indexed source data, copying the filename
+	// Handle any portion before injection point.
 	dup_source_item( index );
-	sources.array[ index ].to = sources.array[ index ].from + size;
+	off_t point = sources.array[ index ].from + size;
+	sources.array[ index ].to = point;
+#if DEBUG
+	fprintf( stderr, "item %d ", index );
+	print_source( &sources.array[ index ] );
+#endif
+	// Adjust item after injection point
 	index++;
 	sources.array[ index ].start = beg;
-	sources.array[ index ].from = sources.array[ index-1 ].to;
+	sources.array[ index ].from = point;
+#if DEBUG
+	fprintf( stderr, "item %d adjust ", index );
+	print_source( &sources.array[ index ] );
+#endif
     }
     size = frags[2].end	- frags[2].beg;
     if ( size ) {
+	// Handle any remaining portion following injection fragment
 	dup_source_item( index );
 	sources.array[ index+1 ].start = frags[2].beg;
-	sources.array[ index+1 ].from = sources.array[ index+1 ].to -size;
+	sources.array[ index+1 ].from += frags[1].end - frags[1].beg;
+#if DEBUG
+	fprintf( stderr, "item %d ", index+1 );
+	print_source( &sources.array[ index+1 ] );
+#endif
     }
-    // Replace the [index] fragment
+    // Set up the injection fragment
     sources.array[ index ].filename = overlay.source.filename;
-    sources.array[ index ].start = beg;
     sources.array[ index ].from = beg;
     sources.array[ index ].to = end;
-    sources.array[ index ].fd = overlay.source.fd; //?
+    sources.array[ index ].fd = overlay.source.fd;
+#if DEBUG
+	fprintf( stderr, "item %d ", index );
+	print_source( &sources.array[ index ] );
+#endif
     return end;
 }
 
@@ -699,9 +699,14 @@ static void overlay_inject() {
     }
     size_t count = 0;
     size_t size = sizeof( overlay.count );
-    if ( read( overlay.source.fd, &count, size ) != size ) {
-	fprintf( stderr, "** error injecting %s\n", overlay.source.filename );
-	usage();
+    size_t n;
+    if ( ( n = read( overlay.source.fd, &count, size ) ) != size ) {
+	if ( n != 0 ) {
+	    fprintf( stderr, "** error injecting %s\n",
+		     overlay.source.filename );
+	    usage();
+	}
+	fprintf( stderr, "** ignoring empty %s\n", overlay.source.filename );
     }
     if ( count == 0 ) {
 	close( overlay.source.fd );
@@ -717,12 +722,16 @@ static void overlay_inject() {
     for ( i = 0; i < count; i++ ) {
 	off_t beg = overlay.table[i].beg;
 	while ( beg < overlay.table[i].end ) {
+#if DEBUG
+	    fprintf( stderr, "inject [%ld,%ld] ", beg, overlay.table[i].end );
+	    print_source( &overlay.source );
+#endif
+	    
 	    beg = overlay_inject_from_region( beg, overlay.table[i].end );
 	}
     }
     free( overlay.table );
     overlay.table = 0;
-    close( overlay.source.fd );
 }
 
 /**
@@ -731,7 +740,7 @@ static void overlay_inject() {
 static void overlay_post_setup() {
     char *end;
     while ( ( end = strchr( overlay.source.filename, ':' ) ) ) {
-	*end = 0; //  
+	*end = 0; //
 	overlay_inject();
 	overlay.source.filename = end + 1;
     }
@@ -796,7 +805,6 @@ static int fusefile_write_buf(const char *path, struct fuse_bufvec *buf,
     if ( strcmp( path, "/" ) != 0 ) {
 	return -ENOENT;
     }
-
     size_t size = 0;
     int i;
     for ( i = 0; i < buf->count; i++ ) {
@@ -967,9 +975,10 @@ static int dump_fragments(int push) {
 		  ENDSOURCE( sources.array[ src ] ) <= x; src++ ) {
 	    // Dump sources.array[src] in full
 	    if ( !push ) {
-		fprintf( stdout, "%s/%ld:%ld\n",
+		fprintf( stdout, "A %s/%ld:%ld\n",
 			 sources.array[ src ].filename,
-			 pos - sources.array[ src ].start,
+			 pos - sources.array[ src ].start +
+			 sources.array[ src ].from,
 			 sources.array[ src ].to );
 	    }
 	    pos = ENDSOURCE( sources.array[ src ] );
@@ -977,10 +986,13 @@ static int dump_fragments(int push) {
 	if ( ( src < sources.count ) && ( sources.array[ src ].start < x ) ) {
 	    // Dump sources.array[src] up to x;
 	    if ( !push ) {
-		fprintf( stdout, "%s/%ld:%ld\n",
+		fprintf( stdout, "B %s/%ld:%ld\n",
 			 sources.array[ src ].filename,
-			 pos - sources.array[ src ].start,
-			 x - sources.array[ src ].start );
+			 sources.array[ src ].from,
+			 //pos - sources.array[ src ].start,
+			 x - sources.array[ src ].start +
+			 sources.array[ src ].from
+			 );
 	    }
 	    pos = ENDSOURCE( sources.array[ src ] );
 	}
@@ -1041,6 +1053,7 @@ static int setup_argv(int argc,char ***argv) {
     // note: (*argv)[ argc ] is the mount point argument
     char *OURS[] = {
 	"-odefault_permissions",
+	//"-s", // Forced single-threading
 	(*argv)[ argc ]
     };
 #define OURSN ( sizeof( OURS ) / sizeof( char* ) )