[PATCH 22/23] qemu-img: implement short --help, remove global help() function

[Michael Tokarev]

now once all individual subcommands has --help support, remove
the large unreadable help() thing and replace it with small
global --help, which refers to individual command --help for
more info.

While at it, also line-wrap list of formats after 74 chars.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
---
 qemu-img.c | 148 +++++++++++------------------------------------------
 1 file changed, 30 insertions(+), 118 deletions(-)

diff --git a/qemu-img.c b/qemu-img.c
index e2c8855ff5..d9c5c6078b 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -94,11 +94,6 @@ typedef enum OutputFormat {
 /* Default to cache=writeback as data integrity is not important for qemu-img 
*/
 #define BDRV_DEFAULT_CACHE "writeback"
 
-static void format_print(void *opaque, const char *name)
-{
-    printf(" %s", name);
-}
-
 static G_NORETURN G_GNUC_PRINTF(2, 3)
 void error_exit(const img_cmd_t *ccmd, const char *fmt, ...)
 {
@@ -154,114 +149,6 @@ static OutputFormat parse_output_format(const img_cmd_t 
*ccmd, const char *arg)
     }
 }
 
-/* Please keep in synch with docs/tools/qemu-img.rst */
-static G_NORETURN
-void help(void)
-{
-    const char *help_msg =
-           QEMU_IMG_VERSION
-           "usage: qemu-img [standard options] command [command options]\n"
-           "QEMU disk image utility\n"
-           "\n"
-           "    '-h', '--help'       display this help and exit\n"
-           "    '-V', '--version'    output version information and exit\n"
-           "    '-T', '--trace'      
[[enable=]<pattern>][,events=<file>][,file=<file>]\n"
-           "                         specify tracing options\n"
-           "\n"
-           "Command syntax:\n"
-#define DEF(option, callback, arg_string)        \
-           "  " arg_string "\n"
-#include "qemu-img-cmds.h"
-#undef DEF
-           "\n"
-           "Command parameters:\n"
-           "  'filename' is a disk image filename\n"
-           "  'objectdef' is a QEMU user creatable object definition. See the 
qemu(1)\n"
-           "    manual page for a description of the object properties. The 
most common\n"
-           "    object type is a 'secret', which is used to supply passwords 
and/or\n"
-           "    encryption keys.\n"
-           "  'fmt' is the disk image format. It is guessed automatically in 
most cases\n"
-           "  'cache' is the cache mode used to write the output disk image, 
the valid\n"
-           "    options are: 'none', 'writeback' (default, except for 
convert), 'writethrough',\n"
-           "    'directsync' and 'unsafe' (default for convert)\n"
-           "  'src_cache' is the cache mode used to read input disk images, 
the valid\n"
-           "    options are the same as for the 'cache' option\n"
-           "  'size' is the disk image size in bytes. Optional suffixes\n"
-           "    'k' or 'K' (kilobyte, 1024), 'M' (megabyte, 1024k), 'G' 
(gigabyte, 1024M),\n"
-           "    'T' (terabyte, 1024G), 'P' (petabyte, 1024T) and 'E' (exabyte, 
1024P)  are\n"
-           "    supported. 'b' is ignored.\n"
-           "  'output_filename' is the destination disk image filename\n"
-           "  'output_fmt' is the destination format\n"
-           "  'options' is a comma separated list of format specific options 
in a\n"
-           "    name=value format. Use -o help for an overview of the options 
supported by\n"
-           "    the used format\n"
-           "  'snapshot_param' is param used for internal snapshot, format\n"
-           "    is 'snapshot.id=[ID],snapshot.name=[NAME]', or\n"
-           "    '[ID_OR_NAME]'\n"
-           "  '-c' indicates that target image must be compressed (qcow format 
only)\n"
-           "  '-u' allows unsafe backing chains. For rebasing, it is assumed 
that old and\n"
-           "       new backing file match exactly. The image doesn't need a 
working\n"
-           "       backing file before rebasing in this case (useful for 
renaming the\n"
-           "       backing file). For image creation, allow creating without 
attempting\n"
-           "       to open the backing file.\n"
-           "  '-h' with or without a command shows this help and lists the 
supported formats\n"
-           "  '-p' show progress of command (only certain commands)\n"
-           "  '-q' use Quiet mode - do not print any output (except errors)\n"
-           "  '-S' indicates the consecutive number of bytes (defaults to 4k) 
that must\n"
-           "       contain only zeros for qemu-img to create a sparse image 
during\n"
-           "       conversion. If the number of bytes is 0, the source will 
not be scanned for\n"
-           "       unallocated or zero sectors, and the destination image will 
always be\n"
-           "       fully allocated\n"
-           "  '--output' takes the format in which the output must be done 
(human or json)\n"
-           "  '-n' skips the target volume creation (useful if the volume is 
created\n"
-           "       prior to running qemu-img)\n"
-           "\n"
-           "Parameters to bitmap subcommand:\n"
-           "  'bitmap' is the name of the bitmap to manipulate, through one or 
more\n"
-           "       actions from '--add', '--remove', '--clear', '--enable', 
'--disable',\n"
-           "       or '--merge source'\n"
-           "  '-g granularity' sets the granularity for '--add' actions\n"
-           "  '-b source' and '-F src_fmt' tell '--merge' actions to find the 
source\n"
-           "       bitmaps from an alternative file\n"
-           "\n"
-           "Parameters to check subcommand:\n"
-           "  '-r' tries to repair any inconsistencies that are found during 
the check.\n"
-           "       '-r leaks' repairs only cluster leaks, whereas '-r all' 
fixes all\n"
-           "       kinds of errors, with a higher risk of choosing the wrong 
fix or\n"
-           "       hiding corruption that has already occurred.\n"
-           "\n"
-           "Parameters to convert subcommand:\n"
-           "  '--bitmaps' copies all top-level persistent bitmaps to 
destination\n"
-           "  '-m' specifies how many coroutines work in parallel during the 
convert\n"
-           "       process (defaults to 8)\n"
-           "  '-W' allow to write to the target out of order rather than 
sequential\n"
-           "\n"
-           "Parameters to snapshot subcommand:\n"
-           "  'snapshot' is the name of the snapshot to create, apply or 
delete\n"
-           "  '-a' applies a snapshot (revert disk to saved state)\n"
-           "  '-c' creates a snapshot\n"
-           "  '-d' deletes a snapshot\n"
-           "  '-l' lists all snapshots in the given image\n"
-           "\n"
-           "Parameters to compare subcommand:\n"
-           "  '-f' first image format\n"
-           "  '-F' second image format\n"
-           "  '-s' run in Strict mode - fail on different image size or sector 
allocation\n"
-           "\n"
-           "Parameters to dd subcommand:\n"
-           "  'bs=BYTES' read and write up to BYTES bytes at a time "
-           "(default: 512)\n"
-           "  'count=N' copy only N input blocks\n"
-           "  'if=FILE' read from FILE\n"
-           "  'of=FILE' write to FILE\n"
-           "  'skip=N' skip N bs-sized blocks at the start of input\n";
-
-    printf("%s\nSupported formats:", help_msg);
-    bdrv_iterate_format(format_print, NULL, false);
-    printf("\n\n" QEMU_HELP_BOTTOM "\n");
-    exit(EXIT_SUCCESS);
-}
-
 /*
  * Is @list safe for accumulate_options()?
  * It is when multiple of them can be joined together separated by ','.
@@ -5866,6 +5753,16 @@ static const img_cmd_t img_cmds[] = {
     { NULL, NULL, },
 };
 
+static void format_print(void *opaque, const char *name)
+{
+    int *np = opaque;
+    *np += printf(" %s", name);
+    if (*np > 74) {
+        printf("\n ");
+        *np = 1;
+    }
+}
+
 int main(int argc, char **argv)
 {
     const img_cmd_t *cmd;
@@ -5893,10 +5790,6 @@ int main(int argc, char **argv)
 
     module_call_init(MODULE_INIT_QOM);
     bdrv_init();
-    if (argc < 2) {
-        error_exit(NULL, "Not enough arguments");
-    }
-
     qemu_add_opts(&qemu_source_opts);
     qemu_add_opts(&qemu_trace_opts);
 
@@ -5909,7 +5802,22 @@ int main(int argc, char **argv)
             unrecognized_option(NULL, argv[optind - 1]);
             return 0;
         case 'h':
-            help();
+            printf(
+QEMU_IMG_VERSION
+"QEMU disk image utility\n"
+"usage: qemu-img [standard options] command [--help | command options]\n"
+"Standard options:\n"
+" -h|--help - display this help and exit\n"
+" -V|--version - display version info and exit\n"
+" -T|--trace TRACE - specify tracing options:\n"
+"   [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
+"Recognized commands (run qemu-img command --help for command-specific 
help):\n");
+            for (cmd = img_cmds; cmd->name != NULL; cmd++) {
+                printf("  %s\n", cmd->name);
+            }
+            c = printf("Supported image formats:");
+            bdrv_iterate_format(format_print, &c, false);
+            printf("\n" QEMU_HELP_BOTTOM "\n");
             return 0;
         case 'V':
             printf(QEMU_IMG_VERSION);
@@ -5920,6 +5828,10 @@ int main(int argc, char **argv)
         }
     }
 
+    if (argc < 2) {
+        error_exit(NULL, "Not enough arguments");
+    }
+
     cmdname = argv[optind];
 
     /* reset getopt_long scanning */
-- 
2.39.2