Add 'prioritize' command to cgpt tool.

cgpt/cgpt.c

 /* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  * Utility for ChromeOS-specific GPT partitions, Please see corresponding .c
  * files for more details.
  */
 
 #include "cgpt.h"
 
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
 
 
 const char* progname;
 const char* command;
 
 struct {
   const char *name;
   int (*fp)(int argc, char *argv[]);
   const char *comment;
 } cmds[] = {
   {"create", cmd_create, "Create or reset GPT headers and tables"},
   {"add", cmd_add, "Add, edit or remove a partition entry"},
   {"show", cmd_show, "Show partition table and entries"},
   {"repair", cmd_repair, "Repair damaged GPT headers and tables"},
   {"boot", cmd_boot, "Edit the PMBR sector for legacy BIOSes"},
   {"find", cmd_find, "Locate a partition by its GUID"},
+  {"prioritize", cmd_prioritize,
+   "Reorder the priority of all kernel partitions"},
 };
 
-
 void Usage(void) {
   int i;
 
-  printf("Usage: %s COMMAND [OPTIONS] DRIVE\n\n"
+  printf("\nUsage: %s COMMAND [OPTIONS] DRIVE\n\n"
          "Supported COMMANDs:\n\n",
          progname);
 
   for (i = 0; i < sizeof(cmds)/sizeof(cmds[0]); ++i) {
-    printf("    %-10s  %s\n", cmds[i].name, cmds[i].comment);
+    printf("    %-15s  %s\n", cmds[i].name, cmds[i].comment);
   }
   printf("\nFor more detailed usage, use %s COMMAND -h\n\n", progname);
 }
 
 
 
 int main(int argc, char *argv[]) {
   int i;
+  int match_count = 0;
+  int match_index = 0;
 
   progname = strrchr(argv[0], '/');
   if (progname)
     progname++;
   else
     progname = argv[0];
 
   if (argc < 2) {
     Usage();
     return CGPT_FAILED;
   }
 
   // increment optind now, so that getopt skips argv[0] in command function
   command = argv[optind++];
 
   // Find the command to invoke.
   for (i = 0; command && i < sizeof(cmds)/sizeof(cmds[0]); ++i) {
+    // exact match?
     if (0 == strcmp(cmds[i].name, command)) {
-      return cmds[i].fp(argc, argv);
+      match_index = i;
+      match_count = 1;
+      break;
+    }
+    // unique match?
+    else if (0 == strncmp(cmds[i].name, command, strlen(command))) {
+      match_index = i;
+      match_count++;
     }
   }
 
-  // Couldn't find the command.
+  if (match_count == 1)
+    return cmds[match_index].fp(argc, argv);
+
+  // Couldn't find a single matching command.
   Usage();
 
   return CGPT_FAILED;
 }