From: Serge Hallyn <serge.hallyn@ubuntu.com>
Date: Fri, 30 Oct 2015 05:14:12 +0000 (+0000)
Subject: only re-open fds if stdin is a tty
X-Git-Tag: lxc-2.0.0.beta1~74
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5d1df05bd5d70793bbd9bafc47aad1bdf5653900;p=thirdparty%2Flxc.git

only re-open fds if stdin is a tty

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
---

diff --git a/src/lxc/lxc_usernsexec.c b/src/lxc/lxc_usernsexec.c
index 26608d6a5..37d92fbed 100644
--- a/src/lxc/lxc_usernsexec.c
+++ b/src/lxc/lxc_usernsexec.c
@@ -278,20 +278,22 @@ int main(int argc, char *argv[])
 	memset(ttyname0, '\0', sizeof(ttyname0));
 	memset(ttyname1, '\0', sizeof(ttyname1));
 	memset(ttyname2, '\0', sizeof(ttyname2));
-	ret = readlink("/proc/self/fd/0", ttyname0, sizeof(ttyname0));
-	if (ret < 0) {
-		perror("unable to open stdin.");
-		exit(1);
-	}
-	ret = readlink("/proc/self/fd/1", ttyname1, sizeof(ttyname1));
-	if (ret < 0) {
-		printf("Warning: unable to open stdout, continuing.");
-		memset(ttyname1, '\0', sizeof(ttyname1));
-	}
-	ret = readlink("/proc/self/fd/2", ttyname2, sizeof(ttyname2));
-	if (ret < 0) {
-		printf("Warning: unable to open stderr, continueing.");
-		memset(ttyname2, '\0', sizeof(ttyname2));
+	if (isatty(0)) {
+		ret = readlink("/proc/self/fd/0", ttyname0, sizeof(ttyname0));
+		if (ret < 0) {
+			perror("unable to open stdin.");
+			exit(1);
+		}
+		ret = readlink("/proc/self/fd/1", ttyname1, sizeof(ttyname1));
+		if (ret < 0) {
+			printf("Warning: unable to open stdout, continuing.");
+			memset(ttyname1, '\0', sizeof(ttyname1));
+		}
+		ret = readlink("/proc/self/fd/2", ttyname2, sizeof(ttyname2));
+		if (ret < 0) {
+			printf("Warning: unable to open stderr, continueing.");
+			memset(ttyname2, '\0', sizeof(ttyname2));
+		}
 	}
 
 	lxc_list_init(&active_map);