As pointed out in a mail to dev expr was segfaulting when multiple
math operations were specified on the command line: eg. 'expr 3 \*
2 + 1'. This happens because the tonum(), introduced in e50d533,
assumed that v->str was always non null. parse() guarantees this
for user input but this is not the case when doop() is called with
the result of a previous calculation. However in that case we know
that v->num is already valid so we can simply return.
---
expr.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/expr.c b/expr.c
index 3afb94b..044c6c1 100644
--- a/expr.c
+++ b/expr.c
@@ -21,7 +21,13 @@ static void
tonum(struct val *v)
{
const char *errstr;
- long long d = strtonum(v->str, LLONG_MIN, LLONG_MAX, &errstr);
+ long long d;
+
+ /* check if val is the result of an earlier calculation */
+ if (!v->str)
+ return;
+
+ d = strtonum(v->str, LLONG_MIN, LLONG_MAX, &errstr);
if (errstr)
enprintf(2, "error: expected integer, got %s\n", v->str);
v->num = d;
--
2.43.0
