Fix zhack argument processing

The argument processing is zhack makes the assumption that getopt()
will not permute argv.  This isn't true for the GNU implementation of
getopt() unless the optstring is prefixed with a '+'.  In which case
this is equivalent to setting the POSIXLY_CORRECT environment variable

In addition, update the usage() and optstrings to reflect the existing
supported options.

Signed-off-by: Brian Behlendorf <[email protected]>
Signed-off-by: liaoyuxiangqin <[email protected]>
Closes #5047

1 files changed, 5 insertions, 4 deletions

diff --git a/cmd/zhack/zhack.c b/cmd/zhack/zhack.c
index cc4f174c6..e76945141 100644
--- a/cmd/zhack/zhack.c
+++ b/cmd/zhack/zhack.c
@@ -69,9 +69,10 @@ usage(void)
 	(void) fprintf(stderr,
 	    "    feature stat <pool>\n"
 	    "        print information about enabled features\n"
-	    "    feature enable [-d desc] <pool> <feature>\n"
+	    "    feature enable [-r] [-d desc] <pool> <feature>\n"
 	    "        add a new enabled feature to the pool\n"
 	    "        -d <desc> sets the feature's description\n"
+	    "        -r set read-only compatible flag for feature\n"
 	    "    feature ref [-md] <pool> <feature>\n"
 	    "        change the refcount on the given feature\n"
 	    "        -d decrease instead of increase the refcount\n"
@@ -318,7 +319,7 @@ zhack_do_feature_enable(int argc, char **argv)
 	feature.fi_feature = SPA_FEATURE_NONE;
 
 	optind = 1;
-	while ((c = getopt(argc, argv, "rmd:")) != -1) {
+	while ((c = getopt(argc, argv, "+rd:")) != -1) {
 		switch (c) {
 		case 'r':
 			feature.fi_flags |= ZFEATURE_FLAG_READONLY_COMPAT;
@@ -416,7 +417,7 @@ zhack_do_feature_ref(int argc, char **argv)
 	feature.fi_feature = SPA_FEATURE_NONE;
 
 	optind = 1;
-	while ((c = getopt(argc, argv, "md")) != -1) {
+	while ((c = getopt(argc, argv, "+md")) != -1) {
 		switch (c) {
 		case 'm':
 			feature.fi_flags |= ZFEATURE_FLAG_MOS;
@@ -522,7 +523,7 @@ main(int argc, char **argv)
 	dprintf_setup(&argc, argv);
 	zfs_prop_init();
 
-	while ((c = getopt(argc, argv, "c:d:")) != -1) {
+	while ((c = getopt(argc, argv, "+c:d:")) != -1) {
 		switch (c) {
 		case 'c':
 			g_importargs.cachefile = optarg;