On Fri, Sep 10, 2021 at 01:41:09PM +0200, [email protected] wrote: > From: Martin Wilck <[email protected]> > > As a first step towards our state machine, avoid the call to > read_all() via recv_packet_from_client(). handle_client() is now > invoked twice for the same connection. The first time it reads > the command length, and later on it reads the command itself > piece-wise, as sent by the client. This will be just a single > read in most cases, but not always. > Reviewed-by: Benjamin Marzinski <[email protected]> > Signed-off-by: Martin Wilck <[email protected]> > --- > multipathd/uxlsnr.c | 90 +++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 75 insertions(+), 15 deletions(-) > > diff --git a/multipathd/uxlsnr.c b/multipathd/uxlsnr.c > index 2fb23c8..eff4f7b 100644 > --- a/multipathd/uxlsnr.c > +++ b/multipathd/uxlsnr.c > @@ -292,6 +292,8 @@ static void handle_inotify(int fd, struct > watch_descriptors *wds) > condlog(1, "Multipath configuration updated.\nReload multipathd > for changes to take effect"); > } > > +static const struct timespec ts_zero = { .tv_sec = 0, }; > + > static int parse_cmd (char *cmd, char **reply, int *len, void *data, > int timeout) > { > @@ -394,23 +396,78 @@ static int uxsock_trigger(char *str, char **reply, int > *len, > return r; > } > > +static void set_client_state(struct client *c, int state) > +{ > + switch(state) > + { > + case CLT_RECV: > + reset_strbuf(&c->reply); > + memset(c->cmd, '\0', sizeof(c->cmd)); > + c->expires = ts_zero; > + /* fallthrough */ > + case CLT_SEND: > + /* reuse these fields for next data transfer */ > + c->len = c->cmd_len = 0; > + break; > + default: > + break; > + } > + c->state = state; > +} > + > static void handle_client(struct client *c, void *trigger_data) > { > int rlen; > - char *inbuf, *reply; > + char *reply; > + ssize_t n; > > - if (recv_packet_from_client(c->fd, &inbuf, uxsock_timeout) != 0) { > - dead_client(c); > - return; > + switch (c->state) { > + case CLT_RECV: > + if (c->cmd_len == 0) { > + /* > + * We got POLLIN; assume that at least the length can > + * be read immediately. > + */ > + get_monotonic_time(&c->expires); > + c->expires.tv_sec += uxsock_timeout / 1000; > + c->expires.tv_nsec += (uxsock_timeout % 1000) * 1000000; > + normalize_timespec(&c->expires); > + n = mpath_recv_reply_len(c->fd, 0); > + if (n == -1) { > + condlog(1, "%s: cli[%d]: failed to receive > reply len", > + __func__, c->fd); > + c->error = -ECONNRESET; > + } else if (n > _MAX_CMD_LEN) { > + condlog(1, "%s: cli[%d]: overlong command (%zd > bytes)", > + __func__, c->fd, n); > + c->error = -ECONNRESET; > + } else { > + c->cmd_len = n; > + condlog(4, "%s: cli[%d]: connected", __func__, > c->fd); > + } > + /* poll for data */ > + return; > + } else if (c->len < c->cmd_len) { > + n = recv(c->fd, c->cmd + c->len, c->cmd_len - c->len, > 0); > + if (n <= 0 && errno != EINTR && errno != EAGAIN) { > + condlog(1, "%s: cli[%d]: error in recv: %m", > + __func__, c->fd); > + c->error = -ECONNRESET; > + return; > + } > + c->len += n; > + if (c->len < c->cmd_len) > + /* continue polling */ > + return; > + set_client_state(c, CLT_PARSE); > + } > + break; > + default: > + break; > } > > - if (!inbuf) { > - condlog(4, "recv_packet_from_client get null request"); > - return; > - } > - > - condlog(4, "cli[%d]: Got request [%s]", c->fd, inbuf); > - uxsock_trigger(inbuf, &reply, &rlen, > + condlog(4, "cli[%d]: Got request [%s]", c->fd, c->cmd); > + uxsock_trigger(c->cmd, &reply, &rlen, > _socket_client_is_root(c->fd), > trigger_data); > > @@ -418,11 +475,12 @@ static void handle_client(struct client *c, void > *trigger_data) > if (send_packet(c->fd, reply) != 0) > dead_client(c); > else > - condlog(4, "cli[%d]: Reply [%d bytes]", c->fd, rlen); > - FREE(reply); > - reply = NULL; > + condlog(4, "cli[%d]: Reply [%zu bytes]", c->fd, > + get_strbuf_len(&c->reply) + 1); > + reset_strbuf(&c->reply); > } > - FREE(inbuf); > + > + set_client_state(c, CLT_RECV); > } > > /* > @@ -553,6 +611,8 @@ void *uxsock_listen(long ux_sock, void *trigger_data) > continue; > } > handle_client(c, trigger_data); > + if (c->error == -ECONNRESET) > + dead_client(c); > } > } > /* see if we got a non-fatal signal */ > -- > 2.33.0
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