From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id CDC893858C83 for ; Sun, 27 Feb 2022 00:01:46 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org CDC893858C83 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-586-Foz097KkOZKU71B1smX6ow-1; Sat, 26 Feb 2022 19:01:45 -0500 X-MC-Unique: Foz097KkOZKU71B1smX6ow-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2FA7A801AFE; Sun, 27 Feb 2022 00:01:44 +0000 (UTC) Received: from f35-1.lan (unknown [10.2.16.40]) by smtp.corp.redhat.com (Postfix) with ESMTP id 83CE55E26C; Sun, 27 Feb 2022 00:01:43 +0000 (UTC) From: Kevin Buettner To: gdb-patches@sourceware.org Subject: [PATCH v3 6/7] QUIT processing w/ explicit throw for gdb_exception_forced_quit Date: Sat, 26 Feb 2022 17:00:50 -0700 Message-Id: <20220227000051.3336149-7-kevinb@redhat.com> In-Reply-To: <20220227000051.3336149-1-kevinb@redhat.com> References: <20220227000051.3336149-1-kevinb@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" X-Spam-Status: No, score=-11.4 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FROM_FMBLA_NEWDOM, GIT_PATCH_0, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H5, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 27 Feb 2022 00:01:48 -0000 This commit contains changes which have an explicit throw for gdb_exception_forced_quit, or, in a couple of cases for gdb_exception, but with a throw following a check to see if 'reason' is RETURN_FORCED_QUIT. Most of these are straightforward - it made sense to continue to allow an existing catch of gdb_exception to also catch gdb_exception_quit; in these cases, a catch/throw for gdb_exception_forced_quit was added. There are two cases, however, which deserve a more detailed explanation. 1) remote_fileio_request in gdb/remote-fileio.c: The try block calls do_remote_fileio_request which can (in turn) call one of the functions in remote_fio_func_map[]. Taking the first one, remote_fileio_func_open(), we have the following call path to maybe_quit(): remote_fileio_func_open(remote_target*, char*) -> target_read_memory(unsigned long, unsigned char*, long) -> target_read(target_ops*, target_object, char const*, unsigned char*, unsigned long, long) -> maybe_quit() Since there is a path to maybe_quit(), we must ensure that the catch block is not permitted to swallow a QUIT representing a SIGTERM. However, for this case, we must take care not to change the way that Ctrl-C / SIGINT is handled; we want to send a suitable EINTR reply to the remote target should that happen. That being the case, I added a catch/throw for gdb_exception_forced_quit. I also did a bit of rewriting here, adding a catch for gdb_exception_quit in favor of checking the 'reason' code in the catch block for gdb_exception. 2) mi_execute_command in gdb/mi/mi-main.c: The try block calls captured_mi_execute_command(); there exists a call path to maybe_quit(): captured_mi_execute_command(ui_out*, mi_parse*) -> mi_cmd_execute(mi_parse*) -> get_current_frame() -> get_prev_frame_always_1(frame_info*) -> frame_register_unwind_location(frame_info*, int, int*, lval_type*, unsigned long*, int*) -> frame_register_unwind(frame_info*, int, int*, int*, lval_type*, unsigned long*, int*, unsigned char*) -> value_entirely_available(value*) -> value_fetch_lazy(value*) -> value_fetch_lazy_memory(value*) -> read_value_memory(value*, long, int, unsigned long, unsigned char*, unsigned long) -> maybe_quit() That being the case, we can't allow the exception handler (catch block) to swallow a gdb_exception_quit for SIGTERM. However, it does seem reasonable to output the exception via the mi interface so that some suitable message regarding SIGTERM might be printed; therefore, I check the exception's 'reason' field for RETURN_FORCED_QUIT and do a throw for this case. --- gdb/event-top.c | 2 ++ gdb/mi/mi-main.c | 4 ++++ gdb/remote-fileio.c | 15 ++++++++++----- gdb/tui/tui-io.c | 4 ++++ gdb/tui/tui.c | 4 ++++ gdb/windows-nat.c | 4 ++++ 6 files changed, 28 insertions(+), 5 deletions(-) diff --git a/gdb/event-top.c b/gdb/event-top.c index 8890c4fae2d..bef70ccbcdc 100644 --- a/gdb/event-top.c +++ b/gdb/event-top.c @@ -1224,6 +1224,8 @@ async_disconnect (gdb_client_data arg) fputs_filtered ("Could not kill the program being debugged", gdb_stderr); exception_print (gdb_stderr, exception); + if (exception.reason == RETURN_FORCED_QUIT) + throw; } for (inferior *inf : all_inferiors ()) diff --git a/gdb/mi/mi-main.c b/gdb/mi/mi-main.c index 4860da7536a..b74a1e2034f 100644 --- a/gdb/mi/mi-main.c +++ b/gdb/mi/mi-main.c @@ -1959,6 +1959,10 @@ mi_execute_command (const char *cmd, int from_tty) somewhere. */ mi_print_exception (command->token, result); mi_out_rewind (current_uiout); + + /* Throw to a higher level catch for SIGTERM sent to GDB. */ + if (result.reason == RETURN_FORCED_QUIT) + throw; } bpstat_do_actions (); diff --git a/gdb/remote-fileio.c b/gdb/remote-fileio.c index 9963f1ebc01..1a0d9452d6f 100644 --- a/gdb/remote-fileio.c +++ b/gdb/remote-fileio.c @@ -1191,12 +1191,17 @@ remote_fileio_request (remote_target *remote, char *buf, int ctrlc_pending_p) { do_remote_fileio_request (remote, buf); } - catch (const gdb_exception &ex) + catch (const gdb_exception_forced_quit &ex) + { + throw; + } + catch (const gdb_exception_quit &ex) { - if (ex.reason == RETURN_QUIT) - remote_fileio_reply (remote, -1, FILEIO_EINTR); - else - remote_fileio_reply (remote, -1, FILEIO_EIO); + remote_fileio_reply (remote, -1, FILEIO_EINTR); + } + catch (const gdb_exception &ex) + { + remote_fileio_reply (remote, -1, FILEIO_EIO); } } diff --git a/gdb/tui/tui-io.c b/gdb/tui/tui-io.c index 8cac1c40f13..4f6f7513142 100644 --- a/gdb/tui/tui-io.c +++ b/gdb/tui/tui-io.c @@ -1259,6 +1259,10 @@ tui_getc (FILE *fp) { return tui_getc_1 (fp); } + catch (const gdb_exception_forced_quit &ex) + { + throw; + } catch (const gdb_exception &ex) { /* Just in case, don't ever let an exception escape to readline. diff --git a/gdb/tui/tui.c b/gdb/tui/tui.c index 776dccf0bb2..bba493fcdb8 100644 --- a/gdb/tui/tui.c +++ b/gdb/tui/tui.c @@ -109,6 +109,10 @@ tui_rl_switch_mode (int notused1, int notused2) tui_enable (); } } + catch (const gdb_exception_forced_quit &ex) + { + throw; + } catch (const gdb_exception &ex) { exception_print (gdb_stderr, ex); diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c index 81e26fe4759..0f77bc94705 100644 --- a/gdb/windows-nat.c +++ b/gdb/windows-nat.c @@ -825,6 +825,10 @@ catch_errors (void (*func) ()) { func (); } + catch (const gdb_exception_forced_quit &ex) + { + throw; + } catch (const gdb_exception &ex) { exception_print (gdb_stderr, ex); -- 2.35.1