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Diffstat (limited to 'grep.c')
-rw-r--r--grep.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/grep.c b/grep.c
index 062b2b6f2..b0d992a6e 100644
--- a/grep.c
+++ b/grep.c
@@ -70,6 +70,8 @@ static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
struct grep_expr *x;
p = *list;
+ if (!p)
+ return NULL;
switch (p->token) {
case GREP_PATTERN: /* atom */
case GREP_PATTERN_HEAD:
@@ -82,8 +84,6 @@ static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
case GREP_OPEN_PAREN:
*list = p->next;
x = compile_pattern_or(list);
- if (!x)
- return NULL;
if (!*list || (*list)->token != GREP_CLOSE_PAREN)
die("unmatched parenthesis");
*list = (*list)->next;
@@ -99,6 +99,8 @@ static struct grep_expr *compile_pattern_not(struct grep_pat **list)
struct grep_expr *x;
p = *list;
+ if (!p)
+ return NULL;
switch (p->token) {
case GREP_NOT:
if (!p->next)
@@ -386,6 +388,8 @@ static int match_expr_eval(struct grep_opt *o,
{
int h = 0;
+ if (!x)
+ die("Not a valid grep expression");
switch (x->node) {
case GREP_NODE_ATOM:
h = match_one_pattern(o, x->u.atom, bol, eol, ctx);