Avoid crash when calling warning too early
authorTom Tromey <tom@tromey.com>
Fri, 5 Oct 2018 20:54:35 +0000 (14:54 -0600)
committerTom Tromey <tom@tromey.com>
Thu, 8 Nov 2018 23:10:21 +0000 (16:10 -0700)
commit20f0d60db4fb5083779c4c9182bbc692f7d2bac5
tree4b194b7c74bf9200bb4b3811c8b426843afa56a0
parentd4718d5c9f9b5c41d88254429c61010c63139130
Avoid crash when calling warning too early

I noticed 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 was later reported as PR gdb/23838.

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 also changed
target_supports_terminal_ours to return bool.

gdb/ChangeLog
2018-11-08  Tom Tromey  <tom@tromey.com>

PR gdb/23555:
PR gdb/23838:
* target.h (target_supports_terminal_ours): Return bool.
* target.c (target_supports_terminal_ours): Handle case where
current_top_target returns nullptr.  Return bool.

gdb/testsuite/ChangeLog
2018-11-08  Tom Tromey  <tom@tromey.com>

PR gdb/23555:
PR gdb/23838:
* gdb.base/warning.exp: New file.
gdb/ChangeLog
gdb/target.c
gdb/target.h
gdb/testsuite/ChangeLog
gdb/testsuite/gdb.base/warning.exp [new file with mode: 0644]