command-line: Add function to print command usage.

[cascardo/ovs.git] / lib / command-line.c

diff --git a/lib/command-line.c b/lib/command-line.c
index 9adf47f..eb0a83b 100644 (file)
--- a/lib/command-line.c
+++ b/lib/command-line.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2013, 2014 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,8 @@
 #include <getopt.h>
 #include <limits.h>
 #include <stdlib.h>
+#include "dynamic-string.h"
+#include "ovs-thread.h"
 #include "util.h"
 #include "vlog.h"
 
@@ -50,6 +52,41 @@ long_options_to_short_options(const struct option options[])
     return xstrdup(short_options);
 }
 
+/* Given the 'struct command' array, prints the usage of all commands. */
+void
+print_commands(const struct command commands[])
+{
+    struct ds ds = DS_EMPTY_INITIALIZER;
+
+    ds_put_cstr(&ds, "The available commands are:\n");
+    for (; commands->name; commands++) {
+        const struct command *c = commands;
+        ds_put_format(&ds, "  %-23s %s\n", c->name, c->usage ? c->usage : "");
+    }
+    printf("%s", ds.string);
+    ds_destroy(&ds);
+}
+
+/* Given the GNU-style options in 'options', prints all options. */
+void
+print_options(const struct option options[])
+{
+    struct ds ds = DS_EMPTY_INITIALIZER;
+
+    for (; options->name; options++) {
+        const struct option *o = options;
+        const char *arg = o->has_arg == required_argument ? "ARG" : "[ARG]";
+
+        ds_put_format(&ds, "--%s%s%s\n", o->name, o->has_arg ? "=" : "",
+                      o->has_arg ? arg : "");
+        if (o->flag == NULL && o->val > 0 && o->val <= UCHAR_MAX) {
+            ds_put_format(&ds, "-%c %s\n", o->val, o->has_arg ? arg : "");
+        }
+    }
+    printf("%s", ds.string);
+    ds_destroy(&ds);
+}
+
 /* 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.
@@ -93,9 +130,16 @@ run_command(int argc, char *argv[], const struct command commands[])
 /* Process title. */
 
 #ifdef __linux__
-static char *argv_start;       /* Start of command-line arguments in memory. */
-static size_t argv_size;       /* Number of bytes of command-line arguments. */
-static char *saved_proctitle;  /* Saved command-line arguments. */
+static struct ovs_mutex proctitle_mutex = OVS_MUTEX_INITIALIZER;
+
+/* Start of command-line arguments in memory. */
+static char *argv_start OVS_GUARDED_BY(proctitle_mutex);
+
+/* Number of bytes of command-line arguments. */
+static size_t argv_size OVS_GUARDED_BY(proctitle_mutex);
+
+/* Saved command-line arguments. */
+static char *saved_proctitle OVS_GUARDED_BY(proctitle_mutex);
 
 /* Prepares the process so that proctitle_set() can later succeed.
  *
@@ -110,11 +154,13 @@ proctitle_init(int argc, char **argv)
 {
     int i;
 
+    assert_single_threaded();
     if (!argc || !argv[0]) {
         /* This situation should never occur, but... */
         return;
     }
 
+    ovs_mutex_lock(&proctitle_mutex);
     /* Specialized version of first loop iteration below. */
     argv_start = argv[0];
     argv_size = strlen(argv[0]) + 1;
@@ -138,18 +184,20 @@ proctitle_init(int argc, char **argv)
         /* Copy out the old argument so we can reuse the space. */
         argv[i] = xstrdup(argv[i]);
     }
+    ovs_mutex_unlock(&proctitle_mutex);
 }
 
-/* Changes the name of the process, as shown by "ps", to 'format', which is
- * formatted as if by printf(). */
+/* Changes the name of the process, as shown by "ps", to the program name
+ * followed by 'format', which is formatted as if by printf(). */
 void
 proctitle_set(const char *format, ...)
 {
     va_list args;
     int n;
 
+    ovs_mutex_lock(&proctitle_mutex);
     if (!argv_start || argv_size < 8) {
-        return;
+        goto out;
     }
 
     if (!saved_proctitle) {
@@ -157,7 +205,10 @@ proctitle_set(const char *format, ...)
     }
 
     va_start(args, format);
-    n = vsnprintf(argv_start, argv_size, format, args);
+    n = snprintf(argv_start, argv_size, "%s: ", program_name);
+    if (n < argv_size) {
+        n += vsnprintf(argv_start + n, argv_size - n, format, args);
+    }
     if (n >= argv_size) {
         /* The name is too long, so add an ellipsis at the end. */
         strcpy(&argv_start[argv_size - 4], "...");
@@ -167,17 +218,22 @@ proctitle_set(const char *format, ...)
         memset(&argv_start[n], '\0', argv_size - n);
     }
     va_end(args);
+
+out:
+    ovs_mutex_unlock(&proctitle_mutex);
 }
 
 /* Restores the process's original command line, as seen by "ps". */
 void
 proctitle_restore(void)
 {
+    ovs_mutex_lock(&proctitle_mutex);
     if (saved_proctitle) {
         memcpy(argv_start, saved_proctitle, argv_size);
         free(saved_proctitle);
         saved_proctitle = NULL;
     }
+    ovs_mutex_unlock(&proctitle_mutex);
 }
 #else  /* !__linux__ */
 /* Stubs that don't do anything on non-Linux systems. */
@@ -187,10 +243,13 @@ proctitle_init(int argc OVS_UNUSED, char **argv OVS_UNUSED)
 {
 }
 
+#if !(defined(__FreeBSD__) || defined(__NetBSD__))
+/* On these platforms we #define this to setproctitle. */
 void
 proctitle_set(const char *format OVS_UNUSED, ...)
 {
 }
+#endif
 
 void
 proctitle_restore(void)