unifdef: Fix collision check when adding symbols.

findsym() is intended for use while parsing input, so it should not be
called from addsym2() or indirectsym(), which are called before any
input is processed.

MFC after:	1 week
Sponsored by:	Klara, Inc.
Reviewed by:	kevans
Differential Revision:	https://reviews.freebsd.org/D48733

contrib/unifdef/unifdef.c

@@ -1488,7 +1488,7 @@ findsym(const char **strp)
 static void
 indirectsym(void)
 {
-	const char *cp;
+	struct macro key = { 0 };
 	int changed;
 	struct macro *sym, *ind;
 
@@ -1497,10 +1497,9 @@ indirectsym(void)
 		RB_FOREACH(sym, MACROMAP, &macro_tree) {
 			if (sym->value == NULL)
 				continue;
-			cp = sym->value;
+			key.name = sym->value;
-			ind = findsym(&cp);
+			ind = RB_FIND(MACROMAP, &macro_tree, &key);
 			if (ind == NULL || ind == sym ||
-			    *cp != '\0' ||
 			    ind->value == NULL ||
 			    ind->value == sym->value)
 				continue;
@@ -1539,10 +1538,10 @@ addsym1(bool ignorethis, bool definethis, char *symval)
 static void
 addsym2(bool ignorethis, const char *symname, const char *val)
 {
-	const char *cp = symname;
+	struct macro key = { .name = symname };
 	struct macro *sym, *r;
 
-	sym = findsym(&cp);
+	sym = RB_FIND(MACROMAP, &macro_tree, &key);
 	if (sym == NULL) {
 		sym = calloc(1, sizeof(*sym));
 		sym->ignore = ignorethis;

usr.bin/unifdef/tests/unifdef_test.sh

@@ -36,7 +36,17 @@ EOF
 	atf_check -s exit:1 -o inline:"b\n" unifdef -DFOO -DFOO=0 <file
 }
 
+atf_test_case sDU
+sDU_head() {
+	atf_set descr "simultaneous use of -s and -D or -U"
+}
+sDU_body() {
+	atf_check unifdef -s -DFOO -UFOO /dev/null
+	atf_check unifdef -s -DFOO -DBAR=FOO /dev/null
+}
+
 atf_init_test_cases() {
 	atf_add_test_case hash_comment
 	atf_add_test_case redefine
+	atf_add_test_case sDU
 }