[RFC] Avoid crash when calling warning too early
Tom Tromey
tom@tromey.com
Sat Oct 6 19:20:00 GMT 2018
I happened to notice that if you pass the name of an existing file
(not a directory) as the argument to --data-directory, gdb will crash:
$ ./gdb -nx --data-directory ./gdb
../../binutils-gdb/gdb/target.c:590:56: runtime error: member call on null pointer of type 'struct target_ops'
This happens because warning ends up calling
target_supports_terminal_ours, which calls current_top_target, which
returns nullptr this early.
This fixes the problem by handling this case specially in
target_supports_terminal_ours.
I wasn't sure whether this warranted a test case, hence the RFC.
gdb/ChangeLog
2018-10-06 Tom Tromey <tom@tromey.com>
* target.c (target_supports_terminal_ours): Handle case where
current_top_target returns nullptr.
---
gdb/ChangeLog | 5 +++++
gdb/target.c | 5 +++++
2 files changed, 10 insertions(+)
diff --git a/gdb/target.c b/gdb/target.c
index 2d98954b54..a261155f29 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -587,6 +587,11 @@ target_terminal::info (const char *arg, int from_tty)
int
target_supports_terminal_ours (void)
{
+ /* This can be called before there is any target, so we must check
+ for nullptr here. */
+ target_ops *top = current_top_target ();
+ if (top == nullptr)
+ return false;
return current_top_target ()->supports_terminal_ours ();
}
--
2.17.1
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