Previously, when there is a user error in argv parsing, qemu-img prints
help text and exits.
Add an error_exit function to print a helpful error message and a hint
to run 'qemu-img --help' for more information.
As a bonus, "qemu-img <cmd> --help" now has a more reasonable exit code
0.
In the future the help text should be split by sub command, and only
print the information for the specified command.
Signed-off-by: Fam Zheng <f...@redhat.com>
---
v2: Address Eric's comments on QEMU_NORETURN, article and
EXIT_{SUCCEESS,FAILURE}.
Signed-off-by: Fam Zheng <f...@redhat.com>
---
qemu-img.c | 73 +++++++++++++++++++++++++++++++++++++++-----------------------
1 file changed, 46 insertions(+), 27 deletions(-)
diff --git a/qemu-img.c b/qemu-img.c
index 8455994..06e92f9 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -57,8 +57,22 @@ static void format_print(void *opaque, const char *name)
printf(" %s", name);
}
+static void QEMU_NORETURN GCC_FMT_ATTR(1, 2) error_exit(const char *fmt, ...)
+{
+ va_list ap;
+
+ error_printf("qemu-img: ");
+
+ va_start(ap, fmt);
+ error_vprintf(fmt, ap);
+ va_end(ap);
+
+ error_printf("\nTry 'qemu-img --help' for more information\n");
+ exit(EXIT_FAILURE);
+}
+
/* Please keep in synch with qemu-img.texi */
-static void help(void)
+static void QEMU_NORETURN help(void)
{
const char *help_msg =
"qemu-img version " QEMU_VERSION ", Copyright (c) 2004-2008 Fabrice
Bellard\n"
@@ -129,7 +143,7 @@ static void help(void)
printf("%s\nSupported formats:", help_msg);
bdrv_iterate_format(format_print, NULL);
printf("\n");
- exit(1);
+ exit(EXIT_SUCCESS);
}
static int GCC_FMT_ATTR(2, 3) qprintf(bool quiet, const char *fmt, ...)
@@ -398,7 +412,7 @@ static int img_create(int argc, char **argv)
}
if (optind >= argc) {
- help();
+ error_exit("Expecting image file name");
}
optind++;
@@ -421,7 +435,7 @@ static int img_create(int argc, char **argv)
img_size = (uint64_t)sval;
}
if (optind != argc) {
- help();
+ error_exit("Unexpected argument: %s", argv[optind]);
}
bdrv_img_create(filename, fmt, base_filename, base_fmt,
@@ -590,7 +604,8 @@ static int img_check(int argc, char **argv)
} else if (!strcmp(optarg, "all")) {
fix = BDRV_FIX_LEAKS | BDRV_FIX_ERRORS;
} else {
- help();
+ error_exit("Unknown option value for -r "
+ "(expecting 'leaks' or 'all'): %s", optarg);
}
break;
case OPTION_OUTPUT:
@@ -602,7 +617,7 @@ static int img_check(int argc, char **argv)
}
}
if (optind != argc - 1) {
- help();
+ error_exit("Expecting one image file name");
}
filename = argv[optind++];
@@ -713,7 +728,7 @@ static int img_commit(int argc, char **argv)
}
}
if (optind != argc - 1) {
- help();
+ error_exit("Expecting one image file name");
}
filename = argv[optind++];
@@ -959,7 +974,7 @@ static int img_compare(int argc, char **argv)
if (optind != argc - 2) {
- help();
+ error_exit("Expecting two image file names");
}
filename1 = argv[optind++];
filename2 = argv[optind++];
@@ -1275,7 +1290,7 @@ static int img_convert(int argc, char **argv)
}
if (bs_n < 1) {
- help();
+ error_exit("Must specify image file name");
}
@@ -1882,7 +1897,7 @@ static int img_info(int argc, char **argv)
}
}
if (optind != argc - 1) {
- help();
+ error_exit("Expecting one image file name");
}
filename = argv[optind++];
@@ -2046,10 +2061,10 @@ static int img_map(int argc, char **argv)
break;
}
}
- if (optind >= argc) {
- help();
+ if (optind != argc - 1) {
+ error_exit("Expecting one image file name");
}
- filename = argv[optind++];
+ filename = argv[optind];
if (output && !strcmp(output, "json")) {
output_format = OFORMAT_JSON;
@@ -2138,7 +2153,7 @@ static int img_snapshot(int argc, char **argv)
return 0;
case 'l':
if (action) {
- help();
+ error_exit("Cannot mix '-l', '-a', '-c', '-d'");
return 0;
}
action = SNAPSHOT_LIST;
@@ -2146,7 +2161,7 @@ static int img_snapshot(int argc, char **argv)
break;
case 'a':
if (action) {
- help();
+ error_exit("Cannot mix '-l', '-a', '-c', '-d'");
return 0;
}
action = SNAPSHOT_APPLY;
@@ -2154,7 +2169,7 @@ static int img_snapshot(int argc, char **argv)
break;
case 'c':
if (action) {
- help();
+ error_exit("Cannot mix '-l', '-a', '-c', '-d'");
return 0;
}
action = SNAPSHOT_CREATE;
@@ -2162,7 +2177,7 @@ static int img_snapshot(int argc, char **argv)
break;
case 'd':
if (action) {
- help();
+ error_exit("Cannot mix '-l', '-a', '-c', '-d'");
return 0;
}
action = SNAPSHOT_DELETE;
@@ -2175,7 +2190,7 @@ static int img_snapshot(int argc, char **argv)
}
if (optind != argc - 1) {
- help();
+ error_exit("Expecting one image file name");
}
filename = argv[optind++];
@@ -2288,8 +2303,11 @@ static int img_rebase(int argc, char **argv)
progress = 0;
}
- if ((optind != argc - 1) || (!unsafe && !out_baseimg)) {
- help();
+ if (optind != argc - 1) {
+ error_exit("Expecting one image file name");
+ }
+ if (!unsafe && !out_baseimg) {
+ error_exit("Must specify backing file (-b) or use unsafe mode (-u)");
}
filename = argv[optind++];
@@ -2549,7 +2567,7 @@ static int img_resize(int argc, char **argv)
/* Remove size from argv manually so that negative numbers are not treated
* as options by getopt. */
if (argc < 3) {
- help();
+ error_exit("Not enough arguments");
return 1;
}
@@ -2576,7 +2594,7 @@ static int img_resize(int argc, char **argv)
}
}
if (optind != argc - 1) {
- help();
+ error_exit("Expecting one image file name");
}
filename = argv[optind++];
@@ -2692,7 +2710,7 @@ static int img_amend(int argc, char **argv)
}
if (!options) {
- help();
+ error_exit("Must specify options (-o)");
}
filename = (optind == argc - 1) ? argv[argc - 1] : NULL;
@@ -2704,7 +2722,7 @@ static int img_amend(int argc, char **argv)
}
if (optind != argc - 1) {
- help();
+ error_exit("Expecting one image file name");
}
bs = bdrv_new_open(filename, fmt, BDRV_O_FLAGS | BDRV_O_RDWR, true, quiet);
@@ -2775,8 +2793,9 @@ int main(int argc, char **argv)
qemu_init_main_loop();
bdrv_init();
- if (argc < 2)
- help();
+ if (argc < 2) {
+ error_exit("Not enough arguments");
+ }
cmdname = argv[1];
argc--; argv++;
@@ -2788,6 +2807,6 @@ int main(int argc, char **argv)
}
/* not found */
- help();
+ error_exit("Command not found: %s", cmdname);
return 0;
}
--
1.9.2
