[lxc-devel] [lxc/master] use lxc_read_nointr() and lxc_write_nointr()

[brauner on Github]

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From 3e6580ec3a22edccf9a211dcac40767727009ef1 Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner at mailbox.org>
Date: Fri, 8 Apr 2016 20:28:59 +0200
Subject: [PATCH] use lxc_read_nointr() and lxc_write_nointr()

Using EPOLLHUP to determine when to exit the loop is unreliable. Let's exit
clean when read() returns -1 && errno != EINTR or 0.

Signed-off-by: Christian Brauner <christian.brauner at mailbox.org>
---
 src/lxc/console.c    | 22 +++++++---------------
 src/lxc/lxc_attach.c |  4 +++-
 2 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/src/lxc/console.c b/src/lxc/console.c
index f874172..a8d09ca 100644
--- a/src/lxc/console.c
+++ b/src/lxc/console.c
@@ -161,33 +161,25 @@ static int lxc_console_cb_con(int fd, uint32_t events, void *data,
 {
 	struct lxc_console *console = (struct lxc_console *)data;
 	char buf[1024];
-	int r,w;
-
-	if (events & EPOLLHUP)
-		return 1;
-
-	w = r = read(fd, buf, sizeof(buf));
-	if (r < 0) {
-		SYSERROR("failed to read");
-		return 1;
-	}
+	int r, w;
 
-	if (!r) {
+	w = r = lxc_read_nointr(fd, buf, sizeof(buf));
+	if (r <= 0) {
 		INFO("console client on fd %d has exited", fd);
 		lxc_mainloop_del_handler(descr, fd);
 		close(fd);
-		return 0;
+		return 1;
 	}
 
 	if (fd == console->peer)
-		w = write(console->master, buf, r);
+		w = lxc_write_nointr(console->master, buf, r);
 
 	if (fd == console->master) {
 		if (console->log_fd >= 0)
-			w = write(console->log_fd, buf, r);
+			w = lxc_write_nointr(console->log_fd, buf, r);
 
 		if (console->peer >= 0)
-			w = write(console->peer, buf, r);
+			w = lxc_write_nointr(console->peer, buf, r);
 	}
 
 	if (w != r)
diff --git a/src/lxc/lxc_attach.c b/src/lxc/lxc_attach.c
index f02ef26..ed3ba0d 100644
--- a/src/lxc/lxc_attach.c
+++ b/src/lxc/lxc_attach.c
@@ -301,8 +301,10 @@ static int get_pty_on_host(struct lxc_container *c, struct wrapargs *wrap, int *
 		goto err2;
 	}
 
-	if (lxc_console_mainloop_add(&descr, conf) < 0)
+	if (lxc_console_mainloop_add(&descr, conf) < 0) {
+		ERROR("Failed to add handlers to lxc mainloop.");
 		goto err3;
+	}
 
 	ret = lxc_mainloop(&descr, -1);
 	if (ret) {