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qemu-img: implement short --help, remove global help() function

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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 75 chars.

Since missing_argument() and unrecognized_option() are now unused,
remove them.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20250531171609.197078-27-mjt@tls.msk.ru>
[kwolf: Fixed up style and formatting]
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Michael Tokarev 2025-05-31 20:16:08 +03:00 • committed by Kevin Wolf
parent d7d0e936f9
commit bf5647ae24
1 changed files with 73 additions and 141 deletions
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214
qemu-img.c
View file

@ -61,6 +61,7 @@
typedef struct img_cmd_t {
const char *name;
int (*handler)(const struct img_cmd_t *ccmd, int argc, char **argv);
const char *description;
} img_cmd_t;
enum {
@ -95,11 +96,6 @@ 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
void tryhelp(const char *argv0)
{
@ -119,18 +115,6 @@ void error_exit(const char *argv0, const char *fmt, ...)
tryhelp(argv0);
}
static G_NORETURN
void missing_argument(const char *option)
{
error_exit("qemu-img", "missing argument for option '%s'", option);
}
static G_NORETURN
void unrecognized_option(const char *option)
{
error_exit("qemu-img", "unrecognized option '%s'", option);
}
/*
* Print --help output for a command and exit.
* @syntax and @description are multi-line with trailing EOL
@ -145,15 +129,14 @@ void cmd_help(const img_cmd_t *ccmd,
{
printf(
"Usage:\n"
"\n"
" %s %s %s"
" %s %s %s\n"
"%s.\n"
"\n"
"Arguments:\n"
" -h, --help\n"
" print this help and exit\n"
"%s\n",
"qemu-img", ccmd->name,
syntax, arguments);
"qemu-img", ccmd->name, syntax, ccmd->description, arguments);
exit(EXIT_SUCCESS);
}
@ -168,114 +151,6 @@ static OutputFormat parse_output_format(const char *argv0, 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 ','.
@ -5999,13 +5874,49 @@ out:
}
static const img_cmd_t img_cmds[] = {
#define DEF(option, callback, arg_string) \
{ option, callback },
#include "qemu-img-cmds.h"
#undef DEF
{ "amend", img_amend,
"Update format-specific options of the image" },
{ "bench", img_bench,
"Run a simple image benchmark" },
{ "bitmap", img_bitmap,
"Perform modifications of the persistent bitmap in the image" },
{ "check", img_check,
"Check basic image integrity" },
{ "commit", img_commit,
"Commit image to its backing file" },
{ "compare", img_compare,
"Check if two images have the same contents" },
{ "convert", img_convert,
"Copy one or more images to another with optional format conversion" },
{ "create", img_create,
"Create and format a new image file" },
{ "dd", img_dd,
"Copy input to output with optional format conversion" },
{ "info", img_info,
"Display information about the image" },
{ "map", img_map,
"Dump image metadata" },
{ "measure", img_measure,
"Calculate the file size required for a new image" },
{ "rebase", img_rebase,
"Change the backing file of the image" },
{ "resize", img_resize,
"Resize the image" },
{ "snapshot", img_snapshot,
"List or manipulate snapshots in the image" },
{ NULL, NULL, },
};
static void format_print(void *opaque, const char *name)
{
int *np = opaque;
if (*np + strlen(name) > 75) {
printf("\n ");
*np = 1;
}
*np += printf(" %s", name);
}
int main(int argc, char **argv)
{
const img_cmd_t *cmd;
@ -6037,16 +5948,35 @@ int main(int argc, char **argv)
qemu_add_opts(&qemu_source_opts);
qemu_add_opts(&qemu_trace_opts);
while ((c = getopt_long(argc, argv, "+:hVT:", long_options, NULL)) != -1) {
while ((c = getopt_long(argc, argv, "+hVT:", long_options, NULL)) != -1) {
switch (c) {
case ':':
missing_argument(argv[optind - 1]);
return 0;
case '?':
unrecognized_option(argv[optind - 1]);
return 0;
case 'h':
help();
printf(
QEMU_IMG_VERSION
"QEMU disk image utility. Usage:\n"
"\n"
" qemu-img [standard options] COMMAND [--help | command options]\n"
"\n"
"Standard options:\n"
" -h, --help\n"
" display this help and exit\n"
" -V, --version\n"
" display version info and exit\n"
" -T,--trace TRACE\n"
" specify tracing options:\n"
" [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
"\n"
"Recognized commands (run qemu-img COMMAND --help for command-specific help):\n\n");
for (cmd = img_cmds; cmd->name != NULL; cmd++) {
printf(" %s - %s\n", cmd->name, cmd->description);
}
printf("\nSupported image formats:\n");
c = 99; /* force a newline */
bdrv_iterate_format(format_print, &c, false);
if (c) {
printf("\n");
}
printf("\n" QEMU_HELP_BOTTOM "\n");
return 0;
case 'V':
printf(QEMU_IMG_VERSION);
@ -6054,6 +5984,8 @@ int main(int argc, char **argv)
case 'T':
trace_opt_parse(optarg);
break;
default:
tryhelp(argv[0]);
}
}