hush: implement "silent" optstrings of ":opts"

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

shell/ash_test/ash-getopts/getopt_silent.right

@@ -0,0 +1,6 @@
+*** optstring:':ac' args:-a -b -c
+1 rc:0 var:'a' OPTIND:2 OPTARG:''
+2 rc:0 var:'?' OPTIND:3 OPTARG:'b'
+3 rc:0 var:'c' OPTIND:4 OPTARG:''
+4 rc:1 var:'?' OPTIND:4 OPTARG:''
+5 rc:1 var:'?' OPTIND:4 OPTARG:''

shell/ash_test/ash-getopts/getopt_silent.tests

@@ -0,0 +1,23 @@
+# Open Group Base Specifications Issue 7:
+# """
+# If an unknown option is met, VAR shall be set to "?". In this case,
+# if the first character in optstring is ":", OPTARG shall be set
+# to the option character found, but no output shall be written
+# to standard error; otherwise, the shell variable OPTARG shall be
+# unset and a diagnostic message shall be written to standard error."
+# ...
+# If an option-argument is missing:
+# If the first character of optstring is ":", VAR shall be set to ":"
+# and OPTARG shall be set to the option character found.
+# """
+
+echo "*** optstring:':ac' args:-a -b -c"
+getopts ":ac" var -a -b -c; echo "1 rc:$? var:'$var' OPTIND:$OPTIND OPTARG:'$OPTARG'"
+getopts ":ac" var -a -b -c; echo "2 rc:$? var:'$var' OPTIND:$OPTIND OPTARG:'$OPTARG'"
+getopts ":ac" var -a -b -c; echo "3 rc:$? var:'$var' OPTIND:$OPTIND OPTARG:'$OPTARG'"
+getopts ":ac" var -a -b -c; echo "4 rc:$? var:'$var' OPTIND:$OPTIND OPTARG:'$OPTARG'"
+# Previous line should result in "rc:1", which is normally treated
+# in getopts loops as exit condition.
+# Nevertheless, let's verify that calling it yet another time doesn't do
+# anything weird:
+getopts ":ac" var -a -b -c; echo "5 rc:$? var:'$var' OPTIND:$OPTIND OPTARG:'$OPTARG'"

shell/hush.c

@@ -9877,11 +9877,6 @@ static int FAST_FUNC builtin_getopts(char **argv)
 /* http://pubs.opengroup.org/onlinepubs/9699919799/utilities/getopts.html
 
 TODO:
-If an invalid option is seen, getopts places ? into VAR and, if
-not silent, prints an error message and unsets OPTARG. If
-getopts is silent, the option character found is placed in
-OPTARG and no diagnostic message is printed.
-
 If a required argument is not found, and getopts is not silent,
 a question mark (?) is placed in VAR, OPTARG is unset, and a
 diagnostic message is printed.  If getopts is silent, then a
@@ -9902,11 +9897,16 @@ Test that VAR is a valid variable name?
 		return EXIT_FAILURE;
 	}
 
-	cp = get_local_var_value("OPTERR");
+	if (optstring[0] == ':') {
-	opterr = cp ? atoi(cp) : 1;
+		opterr = 0;
+	} else {
+		cp = get_local_var_value("OPTERR");
+		opterr = cp ? atoi(cp) : 1;
+	}
 	cp = get_local_var_value("OPTIND");
 	optind = cp ? atoi(cp) : 0;
 	optarg = NULL;
+	cbuf[1] = '\0';
 
 	/* getopts stops on first non-option. Add "+" to force that */
 	/*if (optstring[0] != '+')*/ {
@@ -9920,25 +9920,39 @@ Test that VAR is a valid variable name?
 	else
 		argv = G.global_argv;
 	c = getopt(string_array_len(argv), argv, optstring);
+
+	/* Set OPTARG */
+	/* Always set or unset, never left as-is, even on exit/error:
+	 * "If no option was found, or if the option that was found
+	 * does not have an option-argument, OPTARG shall be unset."
+	 */
+	cp = optarg;
+	if (c == '?') {
+		/* If ":optstring" and unknown option is seen,
+		 * it is stored to OPTARG.
+		 */
+		if (optstring[1] == ':') {
+			cbuf[0] = optopt;
+			cp = cbuf;
+		}
+	}
+	if (cp)
+		set_local_var_from_halves("OPTARG", cp);
+	else
+		unset_local_var("OPTARG");
+
+	/* Convert -1 to "?" */
 	exitcode = EXIT_SUCCESS;
 	if (c < 0) { /* -1: end of options */
 		exitcode = EXIT_FAILURE;
 		c = '?';
 	}
+
+	/* Set OPTIND */
 	cbuf[0] = c;
-	cbuf[1] = '\0';
 	set_local_var_from_halves(var, cbuf);
 	set_local_var_from_halves("OPTIND", utoa(optind));
 
-	/* Always set or unset, never left as-is, even on exit/error:
-	 * "If no option was found, or if the option that was found
-	 * does not have an option-argument, OPTARG shall be unset."
-	 */
-	if (optarg)
-		set_local_var_from_halves("OPTARG", optarg);
-	else
-		unset_local_var("OPTARG");
-
 	return exitcode;
 }
 #endif

shell/hush_test/hush-getopts/getopt_silent.right

@@ -0,0 +1,6 @@
+*** optstring:':ac' args:-a -b -c
+1 rc:0 var:'a' OPTIND:2 OPTARG:''
+2 rc:0 var:'?' OPTIND:3 OPTARG:'b'
+3 rc:0 var:'c' OPTIND:4 OPTARG:''
+4 rc:1 var:'?' OPTIND:4 OPTARG:''
+5 rc:1 var:'?' OPTIND:4 OPTARG:''

shell/hush_test/hush-getopts/getopt_silent.tests

@@ -0,0 +1,23 @@
+# Open Group Base Specifications Issue 7:
+# """
+# If an unknown option is met, VAR shall be set to "?". In this case,
+# if the first character in optstring is ":", OPTARG shall be set
+# to the option character found, but no output shall be written
+# to standard error; otherwise, the shell variable OPTARG shall be
+# unset and a diagnostic message shall be written to standard error."
+# ...
+# If an option-argument is missing:
+# If the first character of optstring is ":", VAR shall be set to ":"
+# and OPTARG shall be set to the option character found.
+# """
+
+echo "*** optstring:':ac' args:-a -b -c"
+getopts ":ac" var -a -b -c; echo "1 rc:$? var:'$var' OPTIND:$OPTIND OPTARG:'$OPTARG'"
+getopts ":ac" var -a -b -c; echo "2 rc:$? var:'$var' OPTIND:$OPTIND OPTARG:'$OPTARG'"
+getopts ":ac" var -a -b -c; echo "3 rc:$? var:'$var' OPTIND:$OPTIND OPTARG:'$OPTARG'"
+getopts ":ac" var -a -b -c; echo "4 rc:$? var:'$var' OPTIND:$OPTIND OPTARG:'$OPTARG'"
+# Previous line should result in "rc:1", which is normally treated
+# in getopts loops as exit condition.
+# Nevertheless, let's verify that calling it yet another time doesn't do
+# anything weird:
+getopts ":ac" var -a -b -c; echo "5 rc:$? var:'$var' OPTIND:$OPTIND OPTARG:'$OPTARG'"