sbase

commit 1c79098178db0f6c26bf4459902000b81c098dd0
parent 46c00d58d59b9be55c4dcdb11605a90baa60d310
Author: Elie Le Vaillant <eolien55@disroot.org>
Date:   Sat, 17 Jan 2026 17:00:46 +0100

dc: prevent segfaults by cleaning up data

Without these changes, dc can undergo segfaults in a variety of
situations (list of cases that segfault, one for changed line):
1. echo 'e(5)' | bc -lc | dc
2. echo 'la sa sa sa' | dc
3. echo '5p' > a.dc; dc a.dc

Diffstat:
M
dc.c
 | 
3
++-
A
tests/0046-dc.c
 | 
22
++++++++++++++++++++++

2 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/dc.c b/dc.c
@@ -1406,6 +1406,7 @@ pop(void)
 	v = *stack;
 	free(stack);
 	stack = v.next;
+	v.next = NULL;
 
 	return v;
 }
@@ -2057,6 +2058,7 @@ eval(void)
 	case 's':
 		rp = lookup(regname());
 		freeval(rp->val);
+		rp->val.type = NVAL;
 		rp->val = pop();
 		break;
 	case 'l':
@@ -2169,7 +2171,6 @@ dc(char *fname)
 	while (moreinput())
 		eval();
 
-	fclose(fp);
 	free(input);
 	input = NULL;
 }
diff --git a/tests/0046-dc.c b/tests/0046-dc.c
@@ -0,0 +1,22 @@
+#!/bin/sh
+
+set -e
+
+tmp1=$$.tmp1
+tmp2=$$.tmp2
+
+trap 'rm -f $tmp1 $tmp2' EXIT
+trap 'exit $?' HUP INT TERM
+
+cat <<EOF >$tmp1
+../dc: stack empty
+5
+148.41315910257660342111
+EOF
+
+echo 5p >$tmp2
+
+../dc $tmp2 <<EOF 2>&1 | diff -u - $tmp1
+`echo 'e(5)' | ../bc -c ../bc.library`
+la sa sa sa
+EOF