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From e8f877d31ff4ffbd7c09744f7244b21c728281be Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Tue, 25 Feb 2014 15:00:04 +0100
Subject: [PATCH 6/7] qemu-img: Allow -o help with incomplete argument list

RH-Author: Kevin Wolf <kwolf@redhat.com>
Message-id: <1393340405-9936-6-git-send-email-kwolf@redhat.com>
Patchwork-id: 57796
O-Subject: [RHEL-7.0 qemu-kvm PATCH 5/6] qemu-img: Allow -o help with incomplete argument list
Bugzilla: 1065873
RH-Acked-by: Juan Quintela <quintela@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

This patch allows using 'qemu-img $subcmd -o help' for the create,
convert and amend subcommands, without specifying the previously
required filename arguments.

Note that it's still allowed and meaningful to specify a filename: An
invocation like 'qemu-img create -o help sheepdog:foo' will also display
options that are provided by the Sheepdog driver.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
(cherry picked from commit a283cb6e58fca846c658360971d23fdd1129db65)

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 qemu-img.c | 58 +++++++++++++++++++++++++++++++++++-----------------------
 1 file changed, 35 insertions(+), 23 deletions(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 qemu-img.c |   58 +++++++++++++++++++++++++++++++++++-----------------------
 1 files changed, 35 insertions(+), 23 deletions(-)

diff --git a/qemu-img.c b/qemu-img.c
index 5002a56..3dc325e 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -244,16 +244,19 @@ static int print_block_option_help(const char *filename, const char *fmt)
         return 1;
     }
 
-    proto_drv = bdrv_find_protocol(filename, true);
-    if (!proto_drv) {
-        error_report("Unknown protocol '%s'", filename);
-        return 1;
-    }
-
     create_options = append_option_parameters(create_options,
                                               drv->create_options);
-    create_options = append_option_parameters(create_options,
-                                              proto_drv->create_options);
+
+    if (filename) {
+        proto_drv = bdrv_find_protocol(filename, true);
+        if (!proto_drv) {
+            error_report("Unknown protocol '%s'", filename);
+            return 1;
+        }
+        create_options = append_option_parameters(create_options,
+                                                  proto_drv->create_options);
+    }
+
     print_option_help(create_options);
     free_option_parameters(create_options);
     return 0;
@@ -390,10 +393,16 @@ static int img_create(int argc, char **argv)
     }
 
     /* Get the filename */
+    filename = (optind < argc) ? argv[optind] : NULL;
+    if (options && has_help_option(options)) {
+        g_free(options);
+        return print_block_option_help(filename, fmt);
+    }
+
     if (optind >= argc) {
         help();
     }
-    filename = argv[optind++];
+    optind++;
 
     /* Get image size, if specified */
     if (optind < argc) {
@@ -416,11 +425,6 @@ static int img_create(int argc, char **argv)
         help();
     }
 
-    if (options && has_help_option(options)) {
-        g_free(options);
-        return print_block_option_help(filename, fmt);
-    }
-
     bdrv_img_create(filename, fmt, base_filename, base_fmt,
                     options, img_size, BDRV_O_FLAGS, &local_err, quiet);
     if (error_is_set(&local_err)) {
@@ -1251,17 +1255,18 @@ static int img_convert(int argc, char **argv)
     }
 
     bs_n = argc - optind - 1;
-    if (bs_n < 1) {
-        help();
-    }
-
-    out_filename = argv[argc - 1];
+    out_filename = bs_n >= 1 ? argv[argc - 1] : NULL;
 
     if (options && has_help_option(options)) {
         ret = print_block_option_help(out_filename, out_fmt);
         goto out;
     }
 
+    if (bs_n < 1) {
+        help();
+    }
+
+
     if (bs_n > 1 && out_baseimg) {
         error_report("-B makes no sense when concatenating multiple input "
                      "images");
@@ -2639,15 +2644,21 @@ static int img_amend(int argc, char **argv)
         }
     }
 
-    if (optind != argc - 1) {
+    if (!options) {
         help();
     }
 
-    if (!options) {
-        help();
+    filename = (optind == argc - 1) ? argv[argc - 1] : NULL;
+    if (fmt && has_help_option(options)) {
+        /* If a format is explicitly specified (and possibly no filename is
+         * given), print option help here */
+        ret = print_block_option_help(filename, fmt);
+        goto out;
     }
 
-    filename = argv[argc - 1];
+    if (optind != argc - 1) {
+        help();
+    }
 
     bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_RDWR, true, quiet);
     if (!bs) {
@@ -2659,6 +2670,7 @@ static int img_amend(int argc, char **argv)
     fmt = bs->drv->format_name;
 
     if (has_help_option(options)) {
+        /* If the format was auto-detected, print option help here */
         ret = print_block_option_help(filename, fmt);
         goto out;
     }
-- 
1.7.1