Add missing long options and --help output.

Options added:
 --format, --cache - for the image in question
 --backing, --backing-format, --backing-cache, --backing-unsafe -
   for the new backing file
(was eg CACHE vs SRC_CACHE, which is unclear).

Probably should rename local variables.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
---
 qemu-img.c | 55 +++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 46 insertions(+), 9 deletions(-)

diff --git a/qemu-img.c b/qemu-img.c
index ce939708d4..2a4bff2872 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -3792,26 +3792,61 @@ static int img_rebase(const img_cmd_t *ccmd, int argc, char **argv)
     for(;;) {
         static const struct option long_options[] = {
             {"help", no_argument, 0, 'h'},
+            {"quiet", no_argument, 0, 'q'},
+            {"progress", no_argument, 0, 'p'},
             {"object", required_argument, 0, OPTION_OBJECT},
             {"image-opts", no_argument, 0, OPTION_IMAGE_OPTS},
             {"force-share", no_argument, 0, 'U'},
+            {"format", required_argument, 0, 'f'},
+            {"cache", required_argument, 0, 't'},
             {"compress", no_argument, 0, 'c'},
+            {"backing", required_argument, 0, 'b'},
+            {"backing-format", required_argument, 0, 'F'},
+            {"backing-cache", required_argument, 0, 'T'},
+            {"backing-unsafe", no_argument, 0, 'u'},
             {0, 0, 0, 0}
         };
-        c = getopt_long(argc, argv, ":hf:F:b:upt:T:qUc",
+        c = getopt_long(argc, argv, "hf:F:b:upt:T:qUc",
                         long_options, NULL);
         if (c == -1) {
             break;
         }
-        switch(c) {
-        case ':':
-            missing_argument(argv[optind - 1]);
-            break;
-        case '?':
-            unrecognized_option(argv[optind - 1]);
-            break;
+        switch (c) {
         case 'h':
-            help();
+            cmd_help(ccmd,
+"[-f FMT | --image-opts] [-t CACHE] [-q] [-U] [-p]\n"
+"        [-b BACKING_FILENAME [-F BACKING_FMT] [-T BACKING_CACHE]] [-u]\n"
+"        [--object OBJDEF] [-c] FILENAME\n"
+"Rebases FILENAME on top of BACKING_FILENAME or no backing file\n"
+,
+"  -q, --quiet\n"
+"     quiet operation\n"
+"  -p, --progress\n"
+"     show progress indicator\n"
+"  -f, --format FMT\n"
+"     specify FILENAME format explicitly\n"
+"  --image-opts\n"
+"     indicates that FILENAME is a complete image specification\n"
+"     instead of a file name (incompatible with --format)\n"
+"  -t, --cache CACHE\n"
+"     cache mode for FILENAME (" BDRV_DEFAULT_CACHE ")\n"
+"  -b, --backing BACKING_FILENAME|\"\"\n"
+"     rebase onto this file (or no backing file)\n"
+"  -F, --backing-format BACKING_FMT\n"
+"     specify format for BACKING_FILENAME\n"
+"  -T, --backing-cache CACHE\n"
+"     BACKING_FILENAME cache mode (" BDRV_DEFAULT_CACHE ")\n"
+"  -u, --backing-unsafe\n"
+"     do not fail if BACKING_FILENAME can not be read\n"
+"  -c, --compress\n"
+"     compress image (when image supports this)\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"
+);
             return 0;
         case 'f':
             fmt = optarg;
@@ -3849,6 +3884,8 @@ static int img_rebase(const img_cmd_t *ccmd, int argc, char **argv)
         case 'c':
             compress = true;
             break;
+        default:
+            tryhelp(argv[0]);
         }
     }
 
-- 
2.39.2