threads / patch / 24654

patchsmart-http: Don't deadlock on server failure

Subject: [PATCH] smart-http: Don't deadlock on server failure

## tl;dr

One message between Aug 6, 2010 and Aug 6, 2010. Diffs are folded; open one to read it.

replies: 0people: 1as markdown or json

Shawn O. Pearce· Aug 6, 2010, 21:19 UTC · lore

If the remote HTTP server fails (e.g. returns 404 or 500) when we posted the RPC to it, we won't have sent anything to the background Git process that is supposed to handle the stream. Because we didn't send anything, its waiting for input from remote-curl, and remote-curl cannot read its response payload because doing so would lead to a deadlock.

Send the background task EOF on its input before we try to read its response back, that way it will break out of its read loop and terminate.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
---
 This was found in Git 1.6.6.1, and exists since we added smart HTTP
 in 1.6.6.  Should apply at least to 'maint', if not older... :-)
 remote-curl.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)
Show changes to remote-curl.c +3 −2
diff --git a/remote-curl.c b/remote-curl.c
index 8f169dd..c9d8f60 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -491,11 +491,12 @@ static int rpc_service(struct rpc_state *rpc, struct discovery *heads)
 		rpc->len = n;
 		err |= post_rpc(rpc);
 	}
-	strbuf_read(&rpc->result, client.out, 0);
 
 	close(client.in);
-	close(client.out);
 	client.in = -1;
+	strbuf_read(&rpc->result, client.out, 0);
+
+	close(client.out);
 	client.out = -1;
 
 	err |= finish_command(&client);
-- 
1.7.2.1.52.g7f7860

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