2 files changed, 146 insertions, 0 deletions
diff --git a/src/run-generator/meson.build b/src/run-generator/meson.build
new file mode 100644
index 0000000..9a4e4ad
--- /dev/null
+++ b/src/run-generator/meson.build
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+executables += [
+        generator_template + {
+                'name' : 'systemd-run-generator',
+                'sources' : files('run-generator.c'),
+        },
+]
diff --git a/src/run-generator/run-generator.c b/src/run-generator/run-generator.c
new file mode 100644
index 0000000..5692b7a
--- /dev/null
+++ b/src/run-generator/run-generator.c
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "escape.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "generator.h"
+#include "glyph-util.h"
+#include "mkdir.h"
+#include "proc-cmdline.h"
+#include "special.h"
+#include "specifier.h"
+#include "strv.h"
+
+static const char *arg_dest = NULL;
+static char **arg_commands = NULL;
+static char *arg_success_action = NULL;
+static char *arg_failure_action = NULL;
+
+STATIC_DESTRUCTOR_REGISTER(arg_commands, strv_freep);
+STATIC_DESTRUCTOR_REGISTER(arg_success_action, freep);
+STATIC_DESTRUCTOR_REGISTER(arg_failure_action, freep);
+
+static int parse(const char *key, const char *value, void *data) {
+        int r;
+
+        assert(key);
+
+        if (streq(key, "systemd.run")) {
+
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+
+                r = strv_extend(&arg_commands, value);
+                if (r < 0)
+                        return log_oom();
+
+        } else if (proc_cmdline_key_streq(key, "systemd.run_success_action")) {
+
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+
+                return free_and_strdup_warn(&arg_success_action, value);
+
+        } else if (proc_cmdline_key_streq(key, "systemd.run_failure_action")) {
+
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+
+                return free_and_strdup_warn(&arg_failure_action, value);
+        }
+
+        return 0;
+}
+
+static int generate(void) {
+        _cleanup_fclose_ FILE *f = NULL;
+        const char *p;
+        int r;
+
+        if (strv_isempty(arg_commands) && !arg_success_action)
+                return 0;
+
+        r = generator_open_unit_file(arg_dest, /* source = */ NULL, "kernel-command-line.service", &f);
+        if (r < 0)
+                return r;
+
+        fputs("[Unit]\n"
+              "Description=Command from Kernel Command Line\n"
+              "Documentation=man:systemd-run-generator(8)\n"
+              "SourcePath=/proc/cmdline\n", f);
+
+        if (!streq_ptr(arg_success_action, "none"))
+                fprintf(f, "SuccessAction=%s\n",
+                        arg_success_action ?: "exit");
+
+        if (!streq_ptr(arg_failure_action, "none"))
+                fprintf(f, "FailureAction=%s\n",
+                        arg_failure_action ?: "exit");
+
+        fputs("\n"
+              "[Service]\n"
+              "Type=oneshot\n"
+              "StandardOutput=journal+console\n", f);
+
+        STRV_FOREACH(c, arg_commands) {
+                _cleanup_free_ char *a = NULL;
+
+                a = specifier_escape(*c);
+                if (!a)
+                        return log_oom();
+
+                fprintf(f, "ExecStart=%s\n", a);
+        }
+
+        r = fflush_and_check(f);
+        if (r < 0)
+                return log_error_errno(r, "Failed to write unit kernel-command-line.service: %m");
+
+        /* Let's create a target we can link "default.target" to */
+        p = strjoina(arg_dest, "/kernel-command-line.target");
+        r = write_string_file(
+                        p,
+                        "# Automatically generated by systemd-run-generator\n\n"
+                        "[Unit]\n"
+                        "Description=Command from Kernel Command Line\n"
+                        "Documentation=man:systemd-run-generator(8)\n"
+                        "SourcePath=/proc/cmdline\n"
+                        "Requires=kernel-command-line.service\n"
+                        "After=kernel-command-line.service\n",
+                        WRITE_STRING_FILE_CREATE|WRITE_STRING_FILE_NOFOLLOW);
+        if (r < 0)
+                return log_error_errno(r, "Failed to create unit file %s: %m", p);
+
+        /* And now redirect default.target to our new target */
+        p = strjoina(arg_dest, "/" SPECIAL_DEFAULT_TARGET);
+        if (symlink("kernel-command-line.target", p) < 0)
+                return log_error_errno(errno, "Failed to link unit file kernel-command-line.target %s %s: %m",
+                                       special_glyph(SPECIAL_GLYPH_ARROW_RIGHT), p);
+
+        return 0;
+}
+
+static int run(const char *dest, const char *dest_early, const char *dest_late) {
+        int r;
+
+        assert_se(arg_dest = dest);
+
+        r = proc_cmdline_parse(parse, NULL, PROC_CMDLINE_RD_STRICT|PROC_CMDLINE_STRIP_RD_PREFIX);
+        if (r < 0)
+                log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");
+
+        return generate();
+}
+
+DEFINE_MAIN_GENERATOR_FUNCTION(run);