af_unix: backport helper functions

src/lxc/af_unix.c

@@ -316,3 +316,73 @@ int lxc_abstract_unix_rcv_credential(int fd, void *data, size_t size)
 out:
 	return ret;
 }
+
+int lxc_unix_sockaddr(struct sockaddr_un *ret, const char *path)
+{
+	size_t len;
+
+	len = strlen(path);
+	if (len == 0)
+		return minus_one_set_errno(EINVAL);
+	if (path[0] != '/' && path[0] != '@')
+		return minus_one_set_errno(EINVAL);
+	if (path[1] == '\0')
+		return minus_one_set_errno(EINVAL);
+
+	if (len + 1 > sizeof(ret->sun_path))
+		return minus_one_set_errno(EINVAL);
+
+	*ret = (struct sockaddr_un){
+	    .sun_family = AF_UNIX,
+	};
+
+	if (path[0] == '@') {
+		memcpy(ret->sun_path + 1, path + 1, len);
+		return (int)(offsetof(struct sockaddr_un, sun_path) + len);
+	}
+
+	memcpy(ret->sun_path, path, len + 1);
+	return (int)(offsetof(struct sockaddr_un, sun_path) + len + 1);
+}
+
+int lxc_unix_connect(struct sockaddr_un *addr)
+{
+	__do_close_prot_errno int fd = -EBADF;
+	int ret;
+	ssize_t len;
+
+	fd = socket(PF_UNIX, SOCK_STREAM, SOCK_CLOEXEC);
+	if (fd < 0)
+		return -1;
+
+	if (addr->sun_path[0] == '\0')
+		len = strlen(&addr->sun_path[1]);
+	else
+		len = strlen(&addr->sun_path[0]);
+	ret = connect(fd, (struct sockaddr *)&addr,
+		      offsetof(struct sockaddr_un, sun_path) + len + 1);
+	if (ret < 0)
+		return -1;
+
+	return move_fd(fd);
+}
+
+int lxc_socket_set_timeout(int fd, int rcv_timeout, int snd_timeout)
+{
+	struct timeval out = {0};
+	int ret;
+
+	out.tv_sec = snd_timeout;
+	ret = setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, (const void *)&out,
+			 sizeof(out));
+	if (ret < 0)
+		return -1;
+
+	out.tv_sec = rcv_timeout;
+	ret = setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (const void *)&out,
+			 sizeof(out));
+	if (ret < 0)
+		return -1;
+
+	return 0;
+}

src/lxc/af_unix.h

@@ -25,6 +25,8 @@
 #define __LXC_AF_UNIX_H
 
 #include <stdio.h>
+#include <sys/socket.h>
+#include <sys/un.h>
 
 /* does not enforce \0-termination */
 extern int lxc_abstract_unix_open(const char *path, int type, int flags);
@@ -37,5 +39,8 @@ extern int lxc_abstract_unix_recv_fds(int fd, int *recvfds, int num_recvfds,
 				      void *data, size_t size);
 extern int lxc_abstract_unix_send_credential(int fd, void *data, size_t size);
 extern int lxc_abstract_unix_rcv_credential(int fd, void *data, size_t size);
+extern int lxc_unix_sockaddr(struct sockaddr_un *ret, const char *path);
+extern int lxc_unix_connect(struct sockaddr_un *addr);
+extern int lxc_socket_set_timeout(int fd, int rcv_timeout, int snd_timeout);
 
 #endif /* __LXC_AF_UNIX_H */