Add missing long options and --help output.

While at it, remove unused option_index variable.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
---
 qemu-img.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/qemu-img.c b/qemu-img.c
index cc51da31cf..3f719bbecf 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -3453,7 +3453,6 @@ static int img_map(const img_cmd_t *ccmd, int argc, char **argv)
 
     fmt = NULL;
     for (;;) {
-        int option_index = 0;
         static const struct option long_options[] = {
             {"help", no_argument, 0, 'h'},
             {"format", required_argument, 0, 'f'},
@@ -3465,20 +3464,33 @@ static int img_map(const img_cmd_t *ccmd, int argc, char **argv)
             {"max-length", required_argument, 0, 'l'},
             {0, 0, 0, 0}
         };
-        c = getopt_long(argc, argv, ":f:s:l:hU",
-                        long_options, &option_index);
+        c = getopt_long(argc, argv, "f:s:l:hU",
+                        long_options, NULL);
         if (c == -1) {
             break;
         }
         switch (c) {
-        case ':':
-            missing_argument(argv[optind - 1]);
-            break;
-        case '?':
-            unrecognized_option(argv[optind - 1]);
-            break;
         case 'h':
-            help();
+            cmd_help(ccmd,
+"[-f FMT | --image-opts] [--object OBJDEF] [--output human|json]\n"
+"        [--start-offset OFFSET] [--max-length LENGTH] [-U] FILENAME\n"
+,
+"  -f, --format FMT\n"
+"     specify FILENAME image format explicitly\n"
+"  --image-opts\n"
+"     indicates that FILENAME is a complete image specification\n"
+"     instead of a file name (incompatible with --format)\n"
+"  --start-offset OFFSET\n"
+"  --max-length LENGTH\n"
+"  --output human|json\n"
+"     specify output format name (default human)\n"
+"  -U, --force-share\n"
+"     open image in shared mode for concurrent access\n"
+"  --object OBJDEF\n"
+"     QEMU user-creatable object (eg encryption key)\n"
+"  FILENAME\n"
+"     image file name (or specification with --image-opts)\n"
+);
             break;
         case 'f':
             fmt = optarg;
@@ -3507,6 +3519,8 @@ static int img_map(const img_cmd_t *ccmd, int argc, char **argv)
         case OPTION_IMAGE_OPTS:
             image_opts = true;
             break;
+        default:
+            tryhelp(argv[0]);
         }
     }
     if (optind != argc - 1) {
-- 
2.39.2