cpupower: use man(1) when calling "cpupower help subcommand"
[linux-2.6.git] / tools / power / cpupower / utils / cpupower.c
index 5844ae0..52bee59 100644 (file)
@@ -11,6 +11,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <errno.h>
 
 #include "builtin.h"
 #include "helpers/helpers.h"
 struct cmd_struct {
        const char *cmd;
        int (*main)(int, const char **);
-       void (*usage)(void);
        int needs_root;
 };
 
 #define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
 
-int cmd_help(int argc, const char **argv);
+static int cmd_help(int argc, const char **argv);
 
 /* Global cpu_info object available for all binaries
  * Info only retrieved from CPU 0
@@ -44,55 +44,66 @@ int be_verbose;
 static void print_help(void);
 
 static struct cmd_struct commands[] = {
-       { "frequency-info",     cmd_freq_info,  freq_info_help, 0       },
-       { "frequency-set",      cmd_freq_set,   freq_set_help,  1       },
-       { "idle-info",          cmd_idle_info,  idle_info_help, 0       },
-       { "set",                cmd_set,        set_help,       1       },
-       { "info",               cmd_info,       info_help,      0       },
-       { "monitor",            cmd_monitor,    monitor_help,   0       },
-       { "help",               cmd_help,       print_help,     0       },
-       /*      { "bench",      cmd_bench,      NULL,           1       }, */
+       { "frequency-info",     cmd_freq_info,  0       },
+       { "frequency-set",      cmd_freq_set,   1       },
+       { "idle-info",          cmd_idle_info,  0       },
+       { "set",                cmd_set,        1       },
+       { "info",               cmd_info,       0       },
+       { "monitor",            cmd_monitor,    0       },
+       { "help",               cmd_help,       0       },
+       /*      { "bench",      cmd_bench,      1       }, */
 };
 
-int cmd_help(int argc, const char **argv)
-{
-       unsigned int i;
-
-       if (argc > 1) {
-               for (i = 0; i < ARRAY_SIZE(commands); i++) {
-                       struct cmd_struct *p = commands + i;
-                       if (strcmp(p->cmd, argv[1]))
-                               continue;
-                       if (p->usage) {
-                               p->usage();
-                               return EXIT_SUCCESS;
-                       }
-               }
-       }
-       print_help();
-       if (argc == 1)
-               return EXIT_SUCCESS; /* cpupower help */
-       return EXIT_FAILURE;
-}
-
 static void print_help(void)
 {
        unsigned int i;
 
 #ifdef DEBUG
-       printf(_("cpupower [ -d ][ -c cpulist ] subcommand [ARGS]\n"));
-       printf(_("  -d, --debug      May increase output (stderr) on some subcommands\n"));
+       printf(_("Usage:\tcpupower [-d|--debug] [-c|--cpu cpulist ] <command> [<args>]\n"));
 #else
-       printf(_("cpupower [ -c cpulist ] subcommand [ARGS]\n"));
+       printf(_("Usage:\tcpupower [-c|--cpu cpulist ] <command> [<args>]\n"));
 #endif
-       printf(_("cpupower --version\n"));
-       printf(_("Supported subcommands are:\n"));
+       printf(_("Supported commands are:\n"));
        for (i = 0; i < ARRAY_SIZE(commands); i++)
                printf("\t%s\n", commands[i].cmd);
-       printf(_("\nSome subcommands can make use of the -c cpulist option.\n"));
-       printf(_("Look at the general cpupower manpage how to use it\n"));
-       printf(_("and read up the subcommand's manpage whether it is supported.\n"));
-       printf(_("\nUse cpupower help subcommand for getting help for above subcommands.\n"));
+       printf(_("\nNot all commands can make use of the -c cpulist option.\n"));
+       printf(_("\nUse 'cpupower help <command>' for getting help for above commands.\n"));
+}
+
+static int print_man_page(const char *subpage)
+{
+       int len;
+       char *page;
+
+       len = 10; /* enough for "cpupower-" */
+       if (subpage != NULL)
+               len += strlen(subpage);
+
+       page = malloc(len);
+       if (!page)
+               return -ENOMEM;
+
+       sprintf(page, "cpupower");
+       if ((subpage != NULL) && strcmp(subpage, "help")) {
+               strcat(page, "-");
+               strcat(page, subpage);
+       }
+
+       execlp("man", "man", page, NULL);
+
+       /* should not be reached */
+       return -EINVAL;
+}
+
+static int cmd_help(int argc, const char **argv)
+{
+       if (argc > 1) {
+               print_man_page(argv[1]); /* exits within execlp() */
+               return EXIT_FAILURE;
+       }
+
+       print_help();
+       return EXIT_SUCCESS;
 }
 
 static void print_version(void)