Mailing List Archive

commit fc1ce6daf6a966df3aa8b7519228f60b040ff072
Author: Nils Goroll <nils.goroll@uplex.de>
Date: Tue Sep 28 18:24:28 2021 +0200

Fix use of ObjGetSpace() for synthetic()

The size argument of ObjGetSpace() is only a hint and storage engines
are free to return whatever size.

If the transient storage returned less space than requested, the
session was closed (no response body sent) with SC_OVERLOAD and
"Error: Could not get storage" logged.

diff --git a/bin/varnishd/cache/cache_req_fsm.c b/bin/varnishd/cache/cache_req_fsm.c
index 2e4ae1650..24c87bd1b 100644
--- a/bin/varnishd/cache/cache_req_fsm.c
+++ b/bin/varnishd/cache/cache_req_fsm.c
@@ -304,6 +304,7 @@ cnt_synth(struct worker *wrk, struct req *req)
struct vsb *synth_body;
ssize_t sz, szl;
uint8_t *ptr;
+ const char *body;

CHECK_OBJ_NOTNULL(wrk, WORKER_MAGIC);
CHECK_OBJ_NOTNULL(req, REQ_MAGIC);
@@ -368,20 +369,26 @@ cnt_synth(struct worker *wrk, struct req *req)
CHECK_OBJ_NOTNULL(req->objcore, OBJCORE_MAGIC);
szl = -1;
if (STV_NewObject(wrk, req->objcore, stv_transient, 1024)) {
+ body = VSB_data(synth_body);
szl = VSB_len(synth_body);
assert(szl >= 0);
- sz = szl;
- if (sz > 0 &&
- ObjGetSpace(wrk, req->objcore, &sz, &ptr) && sz >= szl) {
- memcpy(ptr, VSB_data(synth_body), szl);
- ObjExtend(wrk, req->objcore, szl, 1);
- } else if (sz > 0) {
- szl = -1;
+ while (szl > 0) {
+ sz = szl;
+ if (! ObjGetSpace(wrk, req->objcore, &sz, &ptr)) {
+ szl = -1;
+ break;
+ }
+ if (sz > szl)
+ sz = szl;
+ szl -= sz;
+ memcpy(ptr, body, sz);
+ ObjExtend(wrk, req->objcore, sz, szl == 0 ? 1 : 0);
+ body += sz;
}
}

if (szl >= 0)
- AZ(ObjSetU64(wrk, req->objcore, OA_LEN, szl));
+ AZ(ObjSetU64(wrk, req->objcore, OA_LEN, VSB_len(synth_body)));
HSH_DerefBoc(wrk, req->objcore);
VSB_destroy(&synth_body);

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