Fix: error logged on partial recvmsg() in MSG_DONTWAIT

[lttng-tools.git] / src / common / sessiond-comm / inet.c

diff --git a/src/common/sessiond-comm/inet.c b/src/common/sessiond-comm/inet.c
index e48f2c9ad8195d7cf90bc76d48715e414a6d6d26..57ffbe45c28ed1ae68bded38f4713f901a23deb1 100644 (file)
--- a/src/common/sessiond-comm/inet.c
+++ b/src/common/sessiond-comm/inet.c
@@ -112,31 +112,13 @@ int connect_no_timeout(struct lttcomm_sock *sock)
                        sizeof(sock->sockaddr.addr.sin));
 }
 
-/*
- * Return time_a - time_b  in milliseconds.
- */
-static
-unsigned long time_diff_ms(struct timespec *time_a,
-               struct timespec *time_b)
-{
-       time_t sec_diff;
-       long nsec_diff;
-       unsigned long result_ms;
-
-       sec_diff = time_a->tv_sec - time_b->tv_sec;
-       nsec_diff = time_a->tv_nsec - time_b->tv_nsec;
-
-       result_ms = sec_diff * MSEC_PER_SEC;
-       result_ms += nsec_diff / NSEC_PER_MSEC;
-       return result_ms;
-}
-
 static
 int connect_with_timeout(struct lttcomm_sock *sock)
 {
        unsigned long timeout = lttcomm_get_network_timeout();
        int ret, flags, connect_ret;
        struct timespec orig_time, cur_time;
+       unsigned long diff_ms;
 
        ret = fcntl(sock->fd, F_GETFL, 0);
        if (ret == -1) {
@@ -217,7 +199,12 @@ int connect_with_timeout(struct lttcomm_sock *sock)
                        connect_ret = ret;
                        goto error;
                }
-       } while (time_diff_ms(&cur_time, &orig_time) < timeout);
+               if (timespec_to_ms(timespec_abs_diff(cur_time, orig_time), &diff_ms) < 0) {
+                       ERR("timespec_to_ms input overflows milliseconds output");
+                       connect_ret = -1;
+                       goto error;
+               }
+       } while (diff_ms < timeout);
 
        /* Timeout */
        errno = ETIMEDOUT;
@@ -384,18 +371,31 @@ ssize_t lttcomm_recvmsg_inet_sock(struct lttcomm_sock *sock, void *buf,
                len_last = iov[0].iov_len;
                ret = recvmsg(sock->fd, &msg, flags);
                if (ret > 0) {
+                       if (flags & MSG_DONTWAIT) {
+                               goto end;
+                       }
                        iov[0].iov_base += ret;
                        iov[0].iov_len -= ret;
                        assert(ret <= len_last);
                }
        } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
+
        if (ret < 0) {
+               if (errno == EAGAIN && flags & MSG_DONTWAIT) {
+                       /*
+                        * EAGAIN is expected in non-blocking mode and should
+                        * not be reported as an error. Moreover, if no data
+                        * was read, 0 must not be returned as it would be
+                        * interpreted as an orderly shutdown of the socket.
+                        */
+                       goto end;
+               }
                PERROR("recvmsg inet");
        } else if (ret > 0) {
                ret = len;
        }
        /* Else ret = 0 meaning an orderly shutdown. */
-
+end:
        return ret;
 }