1 files changed, 112 insertions, 0 deletions
diff --git a/src/shared/verbs.c b/src/shared/verbs.c
new file mode 100644
index 0000000..2d19172
--- /dev/null
+++ b/src/shared/verbs.c
@@ -0,0 +1,112 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <getopt.h>
+#include <stdbool.h>
+#include <stddef.h>
+
+#include "env-util.h"
+#include "log.h"
+#include "macro.h"
+#include "process-util.h"
+#include "string-util.h"
+#include "verbs.h"
+#include "virt.h"
+
+/* Wraps running_in_chroot() which is used in various places, but also adds an environment variable check so external
+ * processes can reliably force this on.
+ */
+bool running_in_chroot_or_offline(void) {
+        int r;
+
+        /* Added to support use cases like rpm-ostree, where from %post scripts we only want to execute "preset", but
+         * not "start"/"restart" for example.
+         *
+         * See docs/ENVIRONMENT.md for docs.
+         */
+        r = getenv_bool("SYSTEMD_OFFLINE");
+        if (r < 0 && r != -ENXIO)
+                log_debug_errno(r, "Failed to parse $SYSTEMD_OFFLINE: %m");
+        else if (r >= 0)
+                return r > 0;
+
+        /* We've had this condition check for a long time which basically checks for legacy chroot case like Fedora's
+         * "mock", which is used for package builds.  We don't want to try to start systemd services there, since
+         * without --new-chroot we don't even have systemd running, and even if we did, adding a concept of background
+         * daemons to builds would be an enormous change, requiring considering things like how the journal output is
+         * handled, etc.  And there's really not a use case today for a build talking to a service.
+         *
+         * Note this call itself also looks for a different variable SYSTEMD_IGNORE_CHROOT=1.
+         */
+        r = running_in_chroot();
+        if (r < 0)
+                log_debug_errno(r, "running_in_chroot(): %m");
+
+        return r > 0;
+}
+
+const Verb* verbs_find_verb(const char *name, const Verb verbs[]) {
+        for (size_t i = 0; verbs[i].dispatch; i++)
+                if (streq_ptr(name, verbs[i].verb) ||
+                    (!name && FLAGS_SET(verbs[i].flags, VERB_DEFAULT)))
+                        return &verbs[i];
+
+        /* At the end of the list? */
+        return NULL;
+}
+
+int dispatch_verb(int argc, char *argv[], const Verb verbs[], void *userdata) {
+        const Verb *verb;
+        const char *name;
+        int left;
+
+        assert(verbs);
+        assert(verbs[0].dispatch);
+        assert(argc >= 0);
+        assert(argv);
+        assert(argc >= optind);
+
+        left = argc - optind;
+        argv += optind;
+        optind = 0;
+        name = argv[0];
+
+        verb = verbs_find_verb(name, verbs);
+        if (!verb) {
+                if (name)
+                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                               "Unknown command verb %s.", name);
+                else
+                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                               "Command verb required.");
+        }
+
+        if (!name)
+                left = 1;
+
+        if (verb->min_args != VERB_ANY &&
+            (unsigned) left < verb->min_args)
+                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "Too few arguments.");
+
+        if (verb->max_args != VERB_ANY &&
+            (unsigned) left > verb->max_args)
+                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "Too many arguments.");
+
+        if ((verb->flags & VERB_ONLINE_ONLY) && running_in_chroot_or_offline()) {
+                log_info("Running in chroot, ignoring command '%s'", name ?: verb->verb);
+                return 0;
+        }
+
+        if (name)
+                return verb->dispatch(left, argv, userdata);
+        else {
+                char* fake[2] = {
+                        (char*) verb->verb,
+                        NULL
+                };
+
+                return verb->dispatch(1, fake, userdata);
+        }
+}