3 files changed, 106 insertions, 1 deletions
diff --git a/lib/Makemodule.am b/lib/Makemodule.am
index c29ad2b..b8a1c17 100644
--- a/lib/Makemodule.am
+++ b/lib/Makemodule.am
@@ -1,7 +1,7 @@
 HEADRS = lib/include/util.h lib/include/service.h lib/include/telinit.h
 
 libinit_a_SOURCES = lib/util/delsvc.c lib/util/svcmap.c lib/util/enum_by_name.c
-libinit_a_SOURCES += lib/util/rdsvc.c lib/util/svcscan.c
+libinit_a_SOURCES += lib/util/rdsvc.c lib/util/svcscan.c lib/util/mksock.c
 libinit_a_SOURCES += lib/util/del_svc_list.c lib/util/svc_tsort.c
 libinit_a_SOURCES += lib/util/opensock.c lib/util/enum_to_name.c $(HEADRS)
 libinit_a_CPPFLAGS = $(AM_CPPFLAGS)
diff --git a/lib/include/util.h b/lib/include/util.h
index f63a0d6..18133a8 100644
--- a/lib/include/util.h
+++ b/lib/include/util.h
@@ -35,6 +35,17 @@ typedef struct {
 	int value;
 } enum_map_t;
 
+enum {
+	/* only allow root to connect */
+	SOCK_FLAG_ROOT_ONLY = 0x01,
+
+	/* allow everyone to connect */
+	SOCK_FLAG_EVERYONE = 0x02,
+
+	/* create a datagram socket, otherwise use a stream socket */
+	SOCK_FLAG_DGRAM = 0x04,
+};
+
 /*
 	Search through an array of enum_map_t entries to resolve a string to
 	a numeric value. The end of the map is indicated by a sentinel entry
@@ -49,5 +60,15 @@ const enum_map_t *enum_by_name(const enum_map_t *map, const char *name);
 */
 const char *enum_to_name(const enum_map_t *map, int value);
 
+/*
+	Create a UNIX stream socket at the given path.
+
+	Returns the socket fd, -1 on failure. The function takes care of
+	printing error messages on failure.
+
+	The socket has the CLOEXEC flag set.
+*/
+int mksock(const char *path, int flags);
+
 #endif /* UTIL_H */
 
diff --git a/lib/util/mksock.c b/lib/util/mksock.c
new file mode 100644
index 0000000..ae46096
--- /dev/null
+++ b/lib/util/mksock.c
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * Copyright (C) 2018 - David Oberhollenzer
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <errno.h>
+
+#include "util.h"
+
+int mksock(const char *path, int flags)
+{
+	struct sockaddr_un un;
+	const char *errmsg;
+	int fd, type;
+
+	type = (flags & SOCK_FLAG_DGRAM) ? SOCK_DGRAM : SOCK_STREAM;
+
+	fd = socket(AF_UNIX, type | SOCK_CLOEXEC, 0);
+	if (fd < 0) {
+		perror("socket");
+		return -1;
+	}
+
+	memset(&un, 0, sizeof(un));
+	un.sun_family = AF_UNIX;
+
+	strcpy(un.sun_path, path);
+
+	if (bind(fd, (struct sockaddr *)&un, sizeof(un))) {
+		errmsg ="bind";
+		goto fail_errno;
+	}
+
+	if (flags & SOCK_FLAG_ROOT_ONLY) {
+		if (chown(path, 0, 0)) {
+			errmsg = "chown";
+			goto fail_errno;
+		}
+
+		if (chmod(path, 0770)) {
+			errmsg = "chmod";
+			goto fail_errno;
+		}
+	} else if (flags & SOCK_FLAG_EVERYONE) {
+		if (chmod(path, 0777)) {
+			errmsg = "chmod";
+			goto fail_errno;
+		}
+	}
+
+	if (!(flags & SOCK_FLAG_DGRAM)) {
+		if (listen(fd, 10)) {
+			errmsg = "listen";
+			goto fail_errno;
+		}
+	}
+
+	return fd;
+fail_errno:
+	fprintf(stderr, "%s: %s: %s\n", path, errmsg, strerror(errno));
+	close(fd);
+	unlink(path);
+	return -1;
+}