util: add generalization of verb parsing for command line tools

We should move loginctl, timedatectl, machinectl over to use this new
API instead of a manual one.

2 files changed, 111 insertions, 0 deletions

diff --git a/src/shared/verbs.c b/src/shared/verbs.c
new file mode 100644
index 0000000000..ead2ff60f4
--- /dev/null
+++ b/src/shared/verbs.c
@@ -0,0 +1,77 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 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 "util.h"
+#include "verbs.h"
+
+int dispatch_verb(int argc, char *argv[], const Verb verbs[], void *userdata) {
+        const Verb *verb;
+        const char *name;
+        unsigned i;
+        int left;
+
+        assert(verbs);
+        assert(verbs[0].dispatch);
+        assert(argc >= 0);
+        assert(argv);
+        assert(argc >= optind);
+
+        left = argc - optind;
+        name = argv[optind];
+
+        for (i = 0;; i++) {
+                bool found;
+
+                /* At the end of the list? */
+                if (!verbs[i].dispatch) {
+                        if (name)
+                                log_error("Unknown operation %s.", name);
+                        else
+                                log_error("Requires operation parameter.");
+                        return -EINVAL;
+                }
+
+
+                if (!name)
+                        found = !!(verbs[i].flags & VERB_DEFAULT);
+                else
+                        found = streq(name, verbs[i].verb);
+
+                if (found) {
+                        verb = &verbs[i];
+                        break;
+                }
+        }
+
+        if (verb->min_args != VERB_ANY &&
+            (unsigned) left < verb->min_args) {
+                log_error("Too few arguments.");
+                return -EINVAL;
+        }
+
+        if (verb->max_args != VERB_ANY &&
+            (unsigned) left > verb->max_args) {
+                log_error("Too many argument.s");
+                return -EINVAL;
+        }
+
+        return verb->dispatch(left, argv + optind, userdata);
+}
diff --git a/src/shared/verbs.h b/src/shared/verbs.h
new file mode 100644
index 0000000000..d59e4d59b8
--- /dev/null
+++ b/src/shared/verbs.h
@@ -0,0 +1,34 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 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/>.
+***/
+
+#define VERB_ANY ((unsigned) -1)
+#define VERB_DEFAULT 1
+
+typedef struct {
+        const char *verb;
+        unsigned min_args, max_args;
+        unsigned flags;
+        int (* const dispatch)(int argc, char *argv[], void *userdata);
+} Verb;
+
+int dispatch_verb(int argc, char *argv[], const Verb verbs[], void *userdata);