man: reset OPTIND before parsing args

From jilles: POSIX requires that a script set `OPTIND=1` before using
different sets of parameters with `getopts`, or the results will be
unspecified.

The specific problem observed here is that we would execute `man -f` or
`man -k` without cleaning up state from man_parse_args()' `getopts`
loop.  FreeBSD's /bin/sh seems to reset OPTIND to 1 after we hit the
second getopts loop, rendering the following shift harmless; other
/bin/sh implementations will leave it at what we came into the loop at
(e.g., bash as /bin/sh), shifting off any keywords that we had.

Input from:	jilles
Reviewed by:	allanjude, bapt, imp
Sponsored by:	Klara, Inc.
Differential Revision:	https://reviews.freebsd.org/D32063

1 files changed, 4 insertions, 0 deletions

diff --git a/usr.bin/man/man.sh b/usr.bin/man/man.sh
index f31c464fcc8f..084f4a06829b 100755
--- a/usr.bin/man/man.sh
+++ b/usr.bin/man/man.sh
@@ -243,6 +243,7 @@ is_newer() {
 manpath_parse_args() {
 	local cmd_arg
 
+	OPTIND=1
 	while getopts 'Ldq' cmd_arg; do
 		case "${cmd_arg}" in
 		L)	Lflag=Lflag ;;
@@ -426,6 +427,7 @@ man_display_page_groff() {
 
 	if [ -n "$MANROFFSEQ" ]; then
 		set -- -$MANROFFSEQ
+		OPTIND=1
 		while getopts 'egprtv' preproc_arg; do
 			case "${preproc_arg}" in
 			e)	pipeline="$pipeline | $EQN" ;;
@@ -545,6 +547,7 @@ man_find_and_display() {
 man_parse_args() {
 	local IFS cmd_arg
 
+	OPTIND=1
 	while getopts 'M:P:S:adfhkm:op:tw' cmd_arg; do
 		case "${cmd_arg}" in
 		M)	MANPATH=$OPTARG ;;
@@ -933,6 +936,7 @@ trim() {
 # Parse commandline args for whatis and apropos.
 whatis_parse_args() {
 	local cmd_arg
+	OPTIND=1
 	while getopts 'd' cmd_arg; do
 		case "${cmd_arg}" in
 		d)	debug=$(( $debug + 1 )) ;;