Actually harmless. Reported by Coverity.

Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>
---
 pasta.c | 25 ++++++++-----------------
 qrap.c  | 10 +++++-----
 tap.c   |  5 +++++
 util.h  |  9 +++++++++
 4 files changed, 27 insertions(+), 22 deletions(-)

diff --git a/pasta.c b/pasta.c
index 18df5d2..cd37d16 100644
--- a/pasta.c
+++ b/pasta.c
@@ -120,33 +120,24 @@ static int pasta_setup_ns(void *arg)
 {
 	struct pasta_setup_ns_arg *a = (struct pasta_setup_ns_arg *)arg;
 	char *shell;
-	int fd;
 
 	if (!a->c->netns_only) {
 		char buf[BUFSIZ];
 
 		snprintf(buf, BUFSIZ, "%i %i %i", 0, a->euid, 1);
 
-		fd = open("/proc/self/uid_map", O_WRONLY | O_CLOEXEC);
-		if (write(fd, buf, strlen(buf)) < 0)
-			warn("Cannot set uid_map in namespace");
-		close(fd);
+		FWRITE("/proc/self/uid_map", buf,
+		       "Cannot set uid_map in namespace");
 
-		fd = open("/proc/self/setgroups", O_WRONLY | O_CLOEXEC);
-		if (write(fd, "deny", sizeof("deny")) < 0)
-			warn("Cannot write to setgroups in namespace");
-		close(fd);
+		FWRITE("/proc/self/setgroups", "deny",
+		       "Cannot write to setgroups in namespace");
 
-		fd = open("/proc/self/gid_map", O_WRONLY | O_CLOEXEC);
-		if (write(fd, buf, strlen(buf)) < 0)
-			warn("Cannot set gid_map in namespace");
-		close(fd);
+		FWRITE("/proc/self/gid_map", buf,
+		       "Cannot set gid_map in namespace");
 	}
 
-	fd = open("/proc/sys/net/ipv4/ping_group_range", O_WRONLY | O_CLOEXEC);
-	if (write(fd, "0 0", strlen("0 0")) < 0)
-		warn("Cannot set ping_group_range, ICMP requests might fail");
-	close(fd);
+	FWRITE("/proc/sys/net/ipv4/ping_group_range", "0 0",
+	       "Cannot set ping_group_range, ICMP requests might fail");
 
 	shell = getenv("SHELL") ? getenv("SHELL") : "/bin/sh";
 	if (strstr(shell, "/bash"))
diff --git a/qrap.c b/qrap.c
index 50eea89..17cc472 100644
--- a/qrap.c
+++ b/qrap.c
@@ -234,16 +234,16 @@ int main(int argc, char **argv)
 valid_args:
 	for (i = 1; i < UNIX_SOCK_MAX; i++) {
 		s = socket(AF_UNIX, SOCK_STREAM, 0);
-		if (setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
-			perror("setsockopt SO_RCVTIMEO");
-		if (setsockopt(s, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv)))
-			perror("setsockopt SO_SNDTIMEO");
-
 		if (s < 0) {
 			perror("socket");
 			exit(EXIT_FAILURE);
 		}
 
+		if (setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
+			perror("setsockopt SO_RCVTIMEO");
+		if (setsockopt(s, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv)))
+			perror("setsockopt SO_SNDTIMEO");
+
 		snprintf(addr.sun_path, UNIX_PATH_MAX, UNIX_SOCK_PATH, i);
 		if (connect(s, (const struct sockaddr *)&addr, sizeof(addr)))
 			perror("connect");
diff --git a/tap.c b/tap.c
index 8310891..8110577 100644
--- a/tap.c
+++ b/tap.c
@@ -803,6 +803,11 @@ static void tap_sock_unix_init(struct ctx *c)
 			snprintf(path, UNIX_PATH_MAX, UNIX_SOCK_PATH, i);
 
 		ex = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0);
+		if (ex < 0) {
+			perror("UNIX domain socket check");
+			exit(EXIT_FAILURE);
+		}
+
 		ret = connect(ex, (const struct sockaddr *)&addr, sizeof(addr));
 		if (!ret || (errno != ENOENT && errno != ECONNREFUSED)) {
 			if (*c->sock_path) {
diff --git a/util.h b/util.h
index 91ce3e0..4ed7d94 100644
--- a/util.h
+++ b/util.h
@@ -58,6 +58,15 @@ void trace_init(int enable);
 #define TMPDIR		"/tmp"
 #endif
 
+#define FWRITE(path, buf, str)						\
+	do {								\
+		int fd = open(path, O_WRONLY | O_CLOEXEC);		\
+		if (fd < 0 || write(fd, buf, strlen(buf)))		\
+			warn(str);					\
+		if (fd >= 0)						\
+			close(fd);					\
+	} while (0)
+
 #define V4		0
 #define V6		1
 #define IP_VERSIONS	2
-- 
2.35.1