1 files changed, 73 insertions, 0 deletions
diff --git a/src/systemd-system-update-generator/system-update-generator.c b/src/systemd-system-update-generator/system-update-generator.c
new file mode 100644
index 0000000000..f66993811c
--- /dev/null
+++ b/src/systemd-system-update-generator/system-update-generator.c
@@ -0,0 +1,73 @@
+/***
+  This file is part of systemd.
+
+  Copyright 2012 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <unistd.h>
+
+#include "systemd-basic/fs-util.h"
+#include "systemd-basic/log.h"
+#include "systemd-basic/string-util.h"
+#include "systemd-basic/util.h"
+
+/*
+ * Implements the logic described in
+ * http://freedesktop.org/wiki/Software/systemd/SystemUpdates
+ */
+
+static const char *arg_dest = "/tmp";
+
+static int generate_symlink(void) {
+        const char *p = NULL;
+
+        if (laccess("/system-update", F_OK) < 0) {
+                if (errno == ENOENT)
+                        return 0;
+
+                log_error_errno(errno, "Failed to check for system update: %m");
+                return -EINVAL;
+        }
+
+        p = strjoina(arg_dest, "/default.target");
+        if (symlink(SYSTEM_DATA_UNIT_PATH "/system-update.target", p) < 0)
+                return log_error_errno(errno, "Failed to create symlink %s: %m", p);
+
+        return 0;
+}
+
+int main(int argc, char *argv[]) {
+        int r;
+
+        if (argc > 1 && argc != 4) {
+                log_error("This program takes three or no arguments.");
+                return EXIT_FAILURE;
+        }
+
+        if (argc > 1)
+                arg_dest = argv[2];
+
+        log_set_target(LOG_TARGET_SAFE);
+        log_parse_environment();
+        log_open();
+
+        umask(0022);
+
+        r = generate_symlink();
+
+        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+}