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.
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 -- dm-devel mailing list [email protected] https://listman.redhat.com/mailman/listinfo/dm-devel
