Merge pull request #11827 from keszybz/pkgconfig-variables

[thirdparty/systemd.git] / src / system-update-generator / system-update-generator.c

diff --git a/src/system-update-generator/system-update-generator.c b/src/system-update-generator/system-update-generator.c
index 2e37410bf4c221c6e9a91a25386acfd1b2035ffb..77e265d71076ca7328e7c5c6e2a9f37e5c5af387 100644 (file)
--- a/src/system-update-generator/system-update-generator.c
+++ b/src/system-update-generator/system-update-generator.c
@@ -1,43 +1,26 @@
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
-/***
-  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/>.
-***/
+/* SPDX-License-Identifier: LGPL-2.1+ */
 
 #include <errno.h>
 #include <unistd.h>
 
+#include "fs-util.h"
+#include "generator.h"
 #include "log.h"
+#include "proc-cmdline.h"
+#include "special.h"
+#include "string-util.h"
 #include "util.h"
-#include "unit-name.h"
-#include "path-util.h"
 
 /*
- * Implements the logic described in
- * http://freedesktop.org/wiki/Software/systemd/SystemUpdates
+ * Implements the logic described in systemd.offline-updates(7).
  */
 
-static const char *arg_dest = "/tmp";
+static const char *arg_dest = NULL;
 
 static int generate_symlink(void) {
         const char *p = NULL;
 
-        if (access("/system-update", F_OK) < 0) {
+        if (laccess("/system-update", F_OK) < 0) {
                 if (errno == ENOENT)
                         return 0;
 
@@ -45,33 +28,43 @@ static int generate_symlink(void) {
                 return -EINVAL;
         }
 
-        p = strappenda(arg_dest, "/default.target");
-        if (symlink(SYSTEM_DATA_UNIT_PATH "/system-update.target", p) < 0) {
-                log_error_errno(errno, "Failed to create symlink %s: %m", p);
-                return -errno;
-        }
+        p = strjoina(arg_dest, "/" SPECIAL_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;
+        return 1;
 }
 
-int main(int argc, char *argv[]) {
-        int r;
+static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
+        assert(key);
 
-        if (argc > 1 && argc != 4) {
-                log_error("This program takes three or no arguments.");
-                return EXIT_FAILURE;
-        }
+        /* Check if a run level is specified on the kernel command line. The
+         * command line has higher priority than any on-disk configuration, so
+         * it'll make any symlink we create moot.
+         */
+
+        if (streq(key, "systemd.unit") && !proc_cmdline_value_missing(key, value))
+                log_warning("Offline system update overridden by kernel command line systemd.unit= setting");
+        else if (!value && runlevel_to_target(key))
+                log_warning("Offline system update overridden by runlevel \"%s\" on the kernel command line", key);
 
-        if (argc > 1)
-                arg_dest = argv[2];
+        return 0;
+}
 
-        log_set_target(LOG_TARGET_SAFE);
-        log_parse_environment();
-        log_open();
+static int run(const char *dest, const char *dest_early, const char *dest_late) {
+        int r;
 
-        umask(0022);
+        assert_se(arg_dest = dest_early);
 
         r = generate_symlink();
+        if (r < 0)
+                return r;
+
+        r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, 0);
+        if (r < 0)
+                log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");
 
-        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+        return 0;
 }
+
+DEFINE_MAIN_GENERATOR_FUNCTION(run);