utils-systemd: introduction of systemd interface

Isolate the interface to systemd.

Change-Id: I03ea654da9fab2df0e6eec980b0e5623487d1b73
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

4 files changed, 118 insertions, 36 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index b7c130a..f121a62 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -100,6 +100,7 @@ add_library(utils STATIC
 	utils-dir.c
 	utils-file.c
 	utils-json.c
+	utils-systemd.c
 	verbose.c
 	)
 
diff --git a/src/utils-systemd.c b/src/utils-systemd.c
new file mode 100644
index 0000000..757a52c
--- /dev/null
+++ b/src/utils-systemd.c
@@ -0,0 +1,77 @@
+/*
+ Copyright 2017 IoT.bzh
+
+ author: José Bollo <jose.bollo@iot.bzh>
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+*/
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <poll.h>
+#include <assert.h>
+
+#include <systemd/sd-bus.h>
+#include <systemd/sd-bus-protocol.h>
+
+#include "utils-systemd.h"
+
+#if !defined(SYSTEMD_UNITS_ROOT)
+# define SYSTEMD_UNITS_ROOT "/usr/local/lib/systemd"
+#endif
+
+int systemd_get_unit_path(char *path, size_t pathlen, int isuser, const char *unit, const char *uext)
+{
+	int rc = snprintf(path, pathlen, "%s/%s/%s.%s", 
+			SYSTEMD_UNITS_ROOT,
+			isuser ? "user" : "system",
+			unit,
+			uext);
+
+	if (rc >= 0 && (size_t)rc >= pathlen) {
+		errno = ENAMETOOLONG;
+		rc = -1;
+	}
+	return rc;
+}
+
+int systemd_get_wants_path(char *path, size_t pathlen, int isuser, const char *wanter, const char *unit, const char *uext)
+{
+	int rc = snprintf(path, pathlen, "%s/%s/%s.wants/%s.%s", 
+			SYSTEMD_UNITS_ROOT,
+			isuser ? "user" : "system",
+			wanter,
+			unit,
+			uext);
+
+	if (rc >= 0 && (size_t)rc >= pathlen) {
+		errno = ENAMETOOLONG;
+		rc = -1;
+	}
+	return rc;
+}
+
+int systemd_get_wants_target(char *path, size_t pathlen, const char *unit, const char *uext)
+{
+	int rc = snprintf(path, pathlen, "../%s.%s", unit, uext);
+
+	if (rc >= 0 && (size_t)rc >= pathlen) {
+		errno = ENAMETOOLONG;
+		rc = -1;
+	}
+	return rc;
+}
+
diff --git a/src/utils-systemd.h b/src/utils-systemd.h
new file mode 100644
index 0000000..d149309
--- /dev/null
+++ b/src/utils-systemd.h
@@ -0,0 +1,24 @@
+/*
+ Copyright 2017 IoT.bzh
+
+ author: José Bollo <jose.bollo@iot.bzh>
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+*/
+
+#pragma once
+
+extern int systemd_get_unit_path(char *path, size_t pathlen, int isuser, const char *unit, const char *uext);
+extern int systemd_get_wants_path(char *path, size_t pathlen, int isuser, const char *wanter, const char *unit, const char *uext);
+extern int systemd_get_wants_target(char *path, size_t pathlen, const char *unit, const char *uext);
+
diff --git a/src/wgtpkg-unit.c b/src/wgtpkg-unit.c
index 9e6a1e2..f141766 100644
--- a/src/wgtpkg-unit.c
+++ b/src/wgtpkg-unit.c
@@ -35,13 +35,10 @@
 #include "wgtpkg-mustach.h"
 #include "utils-json.h"
 #include "wgt-json.h"
+#include "utils-systemd.h"
 
 #include "wgtpkg-unit.h"
 
-#if !defined(SYSTEMD_UNITS_ROOT)
-# define SYSTEMD_UNITS_ROOT "/usr/local/lib/systemd"
-#endif
-
 #if 0
 #include <ctype.h>
 #else
@@ -388,54 +385,37 @@ static int check_unit_desc(const struct unitdesc *desc, int tells)
 
 static int get_unit_path(char *path, size_t pathlen, const struct unitdesc *desc)
 {
-	int rc;
+	int rc = systemd_get_unit_path(
+			path, pathlen, desc->scope == unitscope_user,
+			desc->name, desc->type == unittype_socket ? "socket" : "service");
 
-	rc = snprintf(path, pathlen, "%s/%s/%s.%s", 
-			SYSTEMD_UNITS_ROOT,
-			desc->scope == unitscope_system ? "system" : "user",
-			desc->name,
-			desc->type == unittype_socket ? "socket" : "service");
+	if (rc < 0)
+		ERROR("can't get the unit path for %s", desc->name);
 
-	if (rc >= 0 && (size_t)rc >= pathlen) {
-		ERROR("can't set the unit path");
-		errno = EINVAL;
-		rc = -1;
-	}
 	return rc;
 }
 
 static int get_wants_path(char *path, size_t pathlen, const struct unitdesc *desc)
 {
-	int rc;
+	int rc = systemd_get_wants_path(
+			path, pathlen, desc->scope == unitscope_user, desc->wanted_by,
+			desc->name, desc->type == unittype_socket ? "socket" : "service");
 
-	rc = snprintf(path, pathlen, "%s/%s/%s.wants/%s.%s", 
-			SYSTEMD_UNITS_ROOT,
-			desc->scope == unitscope_system ? "system" : "user",
-			desc->wanted_by,
-			desc->name,
-			desc->type == unittype_socket ? "socket" : "service");
+	if (rc < 0)
+		ERROR("can't get the wants path for %s and %s", desc->name, desc->wanted_by);
 
-	if (rc >= 0 && (size_t)rc >= pathlen) {
-		ERROR("can't set the wants path");
-		errno = EINVAL;
-		rc = -1;
-	}
 	return rc;
 }
 
 static int get_wants_target(char *path, size_t pathlen, const struct unitdesc *desc)
 {
-	int rc;
+	int rc = systemd_get_wants_target(
+			path, pathlen,
+			desc->name, desc->type == unittype_socket ? "socket" : "service");
 
-	rc = snprintf(path, pathlen, "../%s.%s", 
-			desc->name,
-			desc->type == unittype_socket ? "socket" : "service");
+	if (rc < 0)
+		ERROR("can't get the wants target for %s", desc->name);
 
-	if (rc >= 0 && (size_t)rc >= pathlen) {
-		ERROR("can't set the wants target");
-		errno = EINVAL;
-		rc = -1;
-	}
 	return rc;
 }