From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Fri, 5 May 2017 04:14:02 +0000 (-0400)
Subject: Add non_block version of functions to UNIX socket wrapper
X-Git-Tag: v2.10.0-rc1~50
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=c72435ad89dc397f89a30faea35274074fbb3047;p=lttng-tools.git

Add non_block version of functions to UNIX socket wrapper

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/src/common/unix.c b/src/common/unix.c
index 11c30781b..2f4df68e6 100644
--- a/src/common/unix.c
+++ b/src/common/unix.c
@@ -216,6 +216,48 @@ ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 	return ret;
 }
 
+/*
+ * Receive data of size len in put that data into the buf param. Using recvmsg
+ * API. Only use with sockets set in non-blocking mode.
+ *
+ * Return the size of received data.
+ */
+LTTNG_HIDDEN
+ssize_t lttcomm_recv_unix_sock_non_block(int sock, void *buf, size_t len)
+{
+	struct msghdr msg;
+	struct iovec iov[1];
+	ssize_t ret;
+
+	memset(&msg, 0, sizeof(msg));
+
+	iov[0].iov_base = buf;
+	iov[0].iov_len = len;
+	msg.msg_iov = iov;
+	msg.msg_iovlen = 1;
+
+retry:
+	ret = lttng_recvmsg_nosigpipe(sock, &msg);
+	if (ret < 0) {
+		if (errno == EINTR) {
+			goto retry;
+		} else {
+			/*
+			 * Only warn about EPIPE when quiet mode is
+			 * deactivated.
+			 * We consider EPIPE as expected.
+			 */
+			if (errno != EPIPE || !lttng_opt_quiet) {
+				PERROR("recvmsg");
+			}
+			goto end;
+		}
+	}
+	ret = len;
+end:
+	return ret;
+}
+
 /*
  * Send buf data of size len. Using sendmsg API.
  *
@@ -226,7 +268,54 @@ ssize_t lttcomm_send_unix_sock(int sock, const void *buf, size_t len)
 {
 	struct msghdr msg;
 	struct iovec iov[1];
-	ssize_t ret = -1;
+	ssize_t ret;
+
+	memset(&msg, 0, sizeof(msg));
+
+	iov[0].iov_base = (void *) buf;
+	iov[0].iov_len = len;
+	msg.msg_iov = iov;
+	msg.msg_iovlen = 1;
+
+	while (iov[0].iov_len) {
+		ret = sendmsg(sock, &msg, 0);
+		if (ret < 0) {
+			if (errno == EINTR) {
+				continue;
+			} else {
+				/*
+				 * Only warn about EPIPE when quiet mode is
+				 * deactivated.
+				 * We consider EPIPE as expected.
+				 */
+				if (errno != EPIPE || !lttng_opt_quiet) {
+					PERROR("sendmsg");
+				}
+				goto end;
+			}
+		}
+		iov[0].iov_len -= ret;
+		iov[0].iov_base += ret;
+	}
+	ret = len;
+end:
+	return ret;
+}
+
+/*
+ * Send buf data of size len. Using sendmsg API.
+ * Only use with non-blocking sockets. The difference with the blocking version
+ * of the function is that this one does not retry to send on partial sends,
+ * except if the interruption was caused by a signal (EINTR).
+ *
+ * Return the size of sent data.
+ */
+LTTNG_HIDDEN
+ssize_t lttcomm_send_unix_sock_non_block(int sock, const void *buf, size_t len)
+{
+	struct msghdr msg;
+	struct iovec iov[1];
+	ssize_t ret;
 
 	memset(&msg, 0, sizeof(msg));
 
@@ -235,17 +324,25 @@ ssize_t lttcomm_send_unix_sock(int sock, const void *buf, size_t len)
 	msg.msg_iov = iov;
 	msg.msg_iovlen = 1;
 
+retry:
 	ret = sendmsg(sock, &msg, 0);
 	if (ret < 0) {
-		/*
-		 * Only warn about EPIPE when quiet mode is deactivated.
-		 * We consider EPIPE as expected.
-		 */
-		if (errno != EPIPE || !lttng_opt_quiet) {
-			PERROR("sendmsg");
+		if (errno == EINTR) {
+			goto retry;
+		} else {
+			/*
+			 * Only warn about EPIPE when quiet mode is
+			 * deactivated.
+			 * We consider EPIPE as expected.
+			 */
+			if (errno != EPIPE || !lttng_opt_quiet) {
+				PERROR("sendmsg");
+			}
+			goto end;
 		}
 	}
-
+	ret = len;
+end:
 	return ret;
 }
 
diff --git a/src/common/unix.h b/src/common/unix.h
index 643512116..886b40e73 100644
--- a/src/common/unix.h
+++ b/src/common/unix.h
@@ -47,7 +47,11 @@ ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd);
 LTTNG_HIDDEN
 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len);
 LTTNG_HIDDEN
+ssize_t lttcomm_recv_unix_sock_non_block(int sock, void *buf, size_t len);
+LTTNG_HIDDEN
 ssize_t lttcomm_send_unix_sock(int sock, const void *buf, size_t len);
+LTTNG_HIDDEN
+ssize_t lttcomm_send_unix_sock_non_block(int sock, const void *buf, size_t len);
 
 LTTNG_HIDDEN
 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len);