Otherwise if we will try to write more data than server can accept
(see `evhttp_set_max_body_size()` for libevent server) we will get `EPIPE` and
will not try to read server's response which must contain 400 error for now
(which is not strictly correct though, it must 413).
```
$ strace regress --no-fork http/data_length_constraints
...
connect(10, {sa_family=AF_INET, sin_port=htons(43988), sin_addr=inet_addr("127.0.0.1")}, 16) = -1 EINPROGRESS (Operation now in progress)
...
writev(10, [{"POST / HTTP/1.1\r\nHost: somehost\r"..., 60}, {"
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"..., 16324}], 2) = 16384
epoll_wait(5, [{EPOLLOUT, {u32=10, u64=10}}, {EPOLLIN, {u32=11, u64=11}}], 32, 50000) = 2
writev(10, [{"
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"..., 16384}], 1) = 16384
ioctl(11, FIONREAD, [32768]) = 0
readv(11, [{"POST / HTTP/1.1\r\nHost: somehost\r"..., 4096}], 1) = 4096
epoll_ctl(5, EPOLL_CTL_DEL, 11, 0x7fff09d41e50) = 0
epoll_ctl(5, EPOLL_CTL_ADD, 11, {EPOLLOUT, {u32=11, u64=11}}) = 0
epoll_wait(5, [{EPOLLOUT, {u32=10, u64=10}}, {EPOLLOUT, {u32=11, u64=11}}], 32, 50000) = 2
writev(10, [{"
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"..., 16384}], 1) = 16384
writev(11, [{"HTTP/1.1 400 Bad Request\r\nConten"..., 129}, {"<HTML><HEAD>\n<TITLE>400 Bad Requ"..., 94}], 2) = 223
epoll_ctl(5, EPOLL_CTL_DEL, 11, 0x7fff09d42080) = 0
shutdown(11, SHUT_WR) = 0
close(11) = 0
epoll_wait(5, [{EPOLLOUT|EPOLLERR|EPOLLHUP, {u32=10, u64=10}}], 32, 50000) = 1
writev(10, [{"
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"..., 16384}], 1) = -1 EPIPE (Broken pipe)
--- SIGPIPE {si_signo=SIGPIPE, si_code=SI_USER, si_pid=13954, si_uid=1000} ---
epoll_ctl(5, EPOLL_CTL_DEL, 10, 0x7fff09d42010) = 0
shutdown(10, SHUT_WR) = -1 ENOTCONN (Transport endpoint is not connected)
close(10) = 0
write(1, "\n FAIL ../test/regress_http.c:3"..., 37
```
Careful reader can ask why it send error even when it didn't read
`evcon->max_body_size`, and the answer will be checks for `evcon->max_body_size
against `Content-Length` header, which contains ~8MB (-2 bytes).
And also if we will not drain the output buffer than we will send buffer that
we didn't send in previous request and instead of sending method via
`evhttp_make_header()`.
Fixes: http/data_length_constraints
Refs: #321
v2: do this only under EVHTTP_CON_READ_ON_WRITE_ERROR flag
}
}
+static void
+evhttp_connection_read_on_write_error(struct evhttp_connection *evcon,
+ struct evhttp_request *req)
+{
+ struct evbuffer *buf;
+
+ evcon->state = EVCON_READING_FIRSTLINE;
+ req->kind = EVHTTP_RESPONSE;
+
+ buf = bufferevent_get_output(evcon->bufev);
+ evbuffer_unfreeze(buf, 1);
+ evbuffer_drain(buf, evbuffer_get_length(buf));
+ evbuffer_freeze(buf, 1);
+
+ bufferevent_setcb(evcon->bufev,
+ evhttp_read_cb,
+ NULL, /* evhttp_write_cb */
+ evhttp_error_cb,
+ evcon);
+ evhttp_connection_start_detectclose(evcon);
+}
+
static void
evhttp_error_cb(struct bufferevent *bufev, short what, void *arg)
{
if (what & BEV_EVENT_TIMEOUT) {
evhttp_connection_fail_(evcon, EVREQ_HTTP_TIMEOUT);
} else if (what & (BEV_EVENT_EOF|BEV_EVENT_ERROR)) {
+ if (what & BEV_EVENT_WRITING &&
+ evcon->flags & EVHTTP_CON_READ_ON_WRITE_ERROR) {
+ evhttp_connection_read_on_write_error(evcon, req);
+ return;
+ }
+
evhttp_connection_fail_(evcon, EVREQ_HTTP_EOF);
} else if (what == BEV_EVENT_CONNECTED) {
} else {
{
int avail_flags = 0;
avail_flags |= EVHTTP_CON_REUSE_CONNECTED_ADDR;
+ avail_flags |= EVHTTP_CON_READ_ON_WRITE_ERROR;
if (flags & ~avail_flags || flags > EVHTTP_CON_PUBLIC_FLAGS_END)
return 1;
/* reuse connection address on retry */
#define EVHTTP_CON_REUSE_CONNECTED_ADDR 0x0008
+/* Try to read error, since server may already send and close
+ * connection, but if at that time we have some data to send then we
+ * can send get EPIPE and fail, while we can read that HTTP error. */
+#define EVHTTP_CON_READ_ON_WRITE_ERROR 0x0010
/* Padding for public flags, @see EVHTTP_CON_* in http-internal.h */
#define EVHTTP_CON_PUBLIC_FLAGS_END 0x100000
/**
projects / libevent / commitdiff