[RFC PATCH v6 1/3] dtc: protect against null pointer dereference in srcpos_string()

[Frank Rowand <frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

From: Frank Rowand <frank.rowand-/MT0OVThwyLZJqsBc5GL+g@public.gmane.org>

Check for NULL pos before dereferencing it in srcpos_string().

Signed-off-by: Frank Rowand <frank.rowand-/MT0OVThwyLZJqsBc5GL+g@public.gmane.org>
---
 srcpos.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Index: b/srcpos.c
===================================================================
--- a/srcpos.c
+++ b/srcpos.c
@@ -268,11 +268,13 @@ srcpos_string(struct srcpos *pos)
 	char *pos_str;
 	int rc;
 
-	if (pos)
+	if (pos && pos->file)
 		fname = pos->file->name;
 
 
-	if (pos->first_line != pos->last_line)
+	if (!pos)
+		rc = asprintf(&pos_str, "%s:<no-line>", fname);
+	else if (pos->first_line != pos->last_line)
 		rc = asprintf(&pos_str, "%s:%d.%d-%d.%d", fname,
 			      pos->first_line, pos->first_column,
 			      pos->last_line, pos->last_column);