Disallow empty condition parts of "if", "while" and "until" compound

commands. Commands like "if then ... fi" and "while do ... done" are no
longer accepted. Bodies of compound commands are still allowed to be
empty, because even though POSIX does not allow them, most shells do.

1 files changed, 6 insertions, 3 deletions

diff --git a/bin/sh/parser.c b/bin/sh/parser.c
index 4df742d..e00df92 100644
--- a/bin/sh/parser.c
+++ b/bin/sh/parser.c
@@ -323,7 +323,8 @@ command(void)
 	case TIF:
 		n1 = (union node *)stalloc(sizeof (struct nif));
 		n1->type = NIF;
-		n1->nif.test = list(0);
+		if ((n1->nif.test = list(0)) == NULL)
+			synexpect(-1);
 		if (readtoken() != TTHEN)
 			synexpect(TTHEN);
 		n1->nif.ifpart = list(0);
@@ -332,7 +333,8 @@ command(void)
 			n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
 			n2 = n2->nif.elsepart;
 			n2->type = NIF;
-			n2->nif.test = list(0);
+			if ((n2->nif.test = list(0)) == NULL)
+				synexpect(-1);
 			if (readtoken() != TTHEN)
 				synexpect(TTHEN);
 			n2->nif.ifpart = list(0);
@@ -352,7 +354,8 @@ command(void)
 		int got;
 		n1 = (union node *)stalloc(sizeof (struct nbinary));
 		n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
-		n1->nbinary.ch1 = list(0);
+		if ((n1->nbinary.ch1 = list(0)) == NULL)
+			synexpect(-1);
 		if ((got=readtoken()) != TDO) {
 TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
 			synexpect(TDO);