Make UNIX socket non-blocking for ctrl_iface

This keeps wpa_cli from hanging forever if the other end of the socket
dies.

Signed-hostap: Ben Greear <greearb@candelatech.com>

src/common/wpa_ctrl.c

@@ -12,6 +12,8 @@
 
 #ifdef CONFIG_CTRL_IFACE_UNIX
 #include <sys/un.h>
+#include <unistd.h>
+#include <fcntl.h>
 #endif /* CONFIG_CTRL_IFACE_UNIX */
 
 #ifdef ANDROID
@@ -73,6 +75,7 @@ struct wpa_ctrl * wpa_ctrl_open(const char *ctrl_path)
 	int ret;
 	size_t res;
 	int tries = 0;
+	int flags;
 
 	ctrl = os_malloc(sizeof(*ctrl));
 	if (ctrl == NULL)
@@ -156,6 +159,19 @@ try_again:
 		return NULL;
 	}
 
+	/*
+	 * Make socket non-blocking so that we don't hang forever if
+	 * target dies unexpectedly.
+	 */
+	flags = fcntl(ctrl->s, F_GETFL);
+	if (flags >= 0) {
+		flags |= O_NONBLOCK;
+		if (fcntl(ctrl->s, F_SETFL, flags) < 0) {
+			perror("fcntl(ctrl->s, O_NONBLOCK)");
+			/* Not fatal, continue on.*/
+		}
+	}
+
 	return ctrl;
 }
 
@@ -289,6 +305,7 @@ int wpa_ctrl_request(struct wpa_ctrl *ctrl, const char *cmd, size_t cmd_len,
 		     void (*msg_cb)(char *msg, size_t len))
 {
 	struct timeval tv;
+	struct os_time started_at;
 	int res;
 	fd_set rfds;
 	const char *_cmd;
@@ -315,7 +332,30 @@ int wpa_ctrl_request(struct wpa_ctrl *ctrl, const char *cmd, size_t cmd_len,
 		_cmd_len = cmd_len;
 	}
 
+	errno = 0;
+	started_at.sec = 0;
+	started_at.usec = 0;
+retry_send:
 	if (send(ctrl->s, _cmd, _cmd_len, 0) < 0) {
+		if (errno == EAGAIN || errno == EBUSY || errno == EWOULDBLOCK)
+		{
+			/*
+			 * Must be a non-blocking socket... Try for a bit
+			 * longer before giving up.
+			 */
+			if (started_at.sec == 0)
+				os_get_time(&started_at);
+			else {
+				struct os_time n;
+				os_get_time(&n);
+				/* Try for a few seconds. */
+				if (n.sec > started_at.sec + 5)
+					goto send_err;
+			}
+			os_sleep(1, 0);
+			goto retry_send;
+		}
+	send_err:
 		os_free(cmd_buf);
 		return -1;
 	}

wpa_supplicant/ctrl_iface_unix.c

@@ -11,6 +11,8 @@
 #include <sys/stat.h>
 #include <grp.h>
 #include <stddef.h>
+#include <unistd.h>
+#include <fcntl.h>
 #ifdef ANDROID
 #include <cutils/sockets.h>
 #endif /* ANDROID */
@@ -259,6 +261,7 @@ wpa_supplicant_ctrl_iface_init(struct wpa_supplicant *wpa_s)
 	char *buf, *dir = NULL, *gid_str = NULL;
 	struct group *grp;
 	char *endp;
+	int flags;
 
 	priv = os_zalloc(sizeof(*priv));
 	if (priv == NULL)
@@ -405,6 +408,20 @@ wpa_supplicant_ctrl_iface_init(struct wpa_supplicant *wpa_s)
 #ifdef ANDROID
 havesock:
 #endif /* ANDROID */
+
+	/*
+	 * Make socket non-blocking so that we don't hang forever if
+	 * target dies unexpectedly.
+	 */
+	flags = fcntl(priv->sock, F_GETFL);
+	if (flags >= 0) {
+		flags |= O_NONBLOCK;
+		if (fcntl(priv->sock, F_SETFL, flags) < 0) {
+			perror("fcntl(ctrl, O_NONBLOCK)");
+			/* Not fatal, continue on.*/
+		}
+	}
+
 	eloop_register_read_sock(priv->sock, wpa_supplicant_ctrl_iface_receive,
 				 wpa_s, priv);
 	wpa_msg_register_cb(wpa_supplicant_ctrl_iface_msg_cb);