Factor out common code from utilities that multiplex commands.

An upcoming commit will add yet another such utility and the code
redundancy was getting to be a bit much.

1 files changed, 41 insertions, 1 deletions

diff --git a/lib/command-line.c b/lib/command-line.c
index 6b79c5eab..a2a43a1c3 100644
--- a/lib/command-line.c
+++ b/lib/command-line.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008 Nicira Networks.
+ * Copyright (c) 2008, 2009 Nicira Networks.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@
 #include "command-line.h"
 #include <getopt.h>
 #include <limits.h>
+#include <stdlib.h>
 #include "util.h"
 #include "vlog.h"
 
@@ -47,3 +48,42 @@ long_options_to_short_options(const struct option options[])
     return xstrdup(short_options);
 }
 
+/* Runs the command designated by argv[0] within the command table specified by
+ * 'commands', which must be terminated by a command whose 'name' member is a
+ * null pointer.
+ *
+ * Command-line options should be stripped off, so that a typical invocation
+ * looks like "run_command(argc - optind, argv + optind, my_commands);". */
+void
+run_command(int argc, char *argv[], const struct command commands[])
+{
+    const struct command *p;
+
+    if (argc < 1) {
+        ovs_fatal(0, "missing command name; use --help for help");
+    }
+
+    for (p = commands; p->name != NULL; p++) {
+        if (!strcmp(p->name, argv[0])) {
+            int n_arg = argc - 1;
+            if (n_arg < p->min_args) {
+                ovs_fatal(0, "'%s' command requires at least %d arguments",
+                          p->name, p->min_args);
+            } else if (n_arg > p->max_args) {
+                ovs_fatal(0, "'%s' command takes at most %d arguments",
+                          p->name, p->max_args);
+            } else {
+                p->handler(argc, argv);
+                if (ferror(stdout)) {
+                    ovs_fatal(0, "write to stdout failed");
+                }
+                if (ferror(stderr)) {
+                    ovs_fatal(0, "write to stderr failed");
+                }
+                return;
+            }
+        }
+    }
+
+    ovs_fatal(0, "unknown command '%s'; use --help for help", argv[0]);
+}