ip/httpfile: fix flushes, fix concurrent reads, set error string

Tflush handling was wrong, we cannot respond to the old
request if we have not actually removed the req from the
in progress block queue.

when reads are issued concurrently, we have to set b->len
before the block is inserted into the inprogress list.
otherwise findblock() is unable to find it and no requests
can be queued on the block. this caused the same offset
to be downloaded multiple times.

set the errstr in getrange() so in case of an error, we dont
get some random previous error string.

1 files changed, 13 insertions, 8 deletions

diff --git a/sys/src/cmd/ip/httpfile.c b/sys/src/cmd/ip/httpfile.c
index 995a1cfaa..192018c75 100644
--- a/sys/src/cmd/ip/httpfile.c
+++ b/sys/src/cmd/ip/httpfile.c
@@ -100,6 +100,8 @@ delreq(Block *b, Req *r)
 			*l = r->aux;
 			if(*l == nil)
 				b->erq = l;
+			r->aux = nil;
+			respond(r, "interrupted");
 			return;
 		}
 	}
@@ -205,10 +207,6 @@ getrange(Block *b)
 	int fd, cfd;
 	uchar *data;
 
-	b->len = Blocksize;
-	if(b->off + b->len > size)
-		b->len = size - b->off;
-
 	if(debug)
 		print("getrange: %lld %lld\n", b->off, b->len);
 
@@ -230,6 +228,8 @@ getrange(Block *b)
 		close(fd);
 		return nil;
 	}
+
+	werrstr("bad contentrange header");
 	if(readstring(cfd, buf, sizeof(buf)) <= 0){
 Badrange:
 		close(cfd);
@@ -244,6 +244,7 @@ Badrange:
 
 	/* read body data */
 	data = emalloc9p(b->len);
+	werrstr("body data truncated");
 	if(readfile(fd, (char*)data, b->len) != b->len){
 		close(fd);
 		free(data);
@@ -410,6 +411,9 @@ fileread(Req *r)
 	if((b = findblock(&inprogress, r->ifcall.offset)) == nil){
 		b = emalloc9p(sizeof(Block));
 		b->off = r->ifcall.offset - (r->ifcall.offset % Blocksize);
+		b->len = Blocksize;
+		if(b->off + b->len > size)
+			b->len = size - b->off;
 		addblock(&inprogress, b);
 		if(inprogress.first == b)
 			sendp(httpchan, b);
@@ -467,10 +471,11 @@ fsnetproc(void*)
 		switch(r->ifcall.type){
 		case Tflush:
 			o = r->oldreq;
-			b = findblock(&inprogress, o->ifcall.offset);
-			if(b != nil)
-				delreq(b, o);
-			respond(o, "interrupted");
+			if(o->ifcall.type == Tread){
+				b = findblock(&inprogress, o->ifcall.offset);
+				if(b != nil)
+					delreq(b, o);
+			}
 			respond(r, nil);
 			break;
 		case Tread: