From patchwork Mon Dec 12 20:30:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pedro Alves X-Patchwork-Id: 61827 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id C4CB1384D3C1 for ; Mon, 12 Dec 2022 20:31:48 +0000 (GMT) X-Original-To: gdb-patches@sourceware.org Delivered-To: gdb-patches@sourceware.org Received: from mail-wm1-f50.google.com (mail-wm1-f50.google.com [209.85.128.50]) by sourceware.org (Postfix) with ESMTPS id C3B21384E20B for ; Mon, 12 Dec 2022 20:31:04 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org C3B21384E20B Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=palves.net Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-wm1-f50.google.com with SMTP id ay8-20020a05600c1e0800b003d0808d2826so10093174wmb.1 for ; Mon, 12 Dec 2022 12:31:04 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Z/He0zWmcOxVvjTSJIxulGSi0gKHtHoUEcfkNerJ9sY=; b=Q3Dp5Zh9ii1i7T50AY5kZngxCvjFD/EY4SsntXyGgLYZcnj79tzh+BdootjPKcKN7R Ej0cwLri9fDUMNt5o0UhrHlGyVWHqgnhcZ1gVL8J0Q+Fj595S1We+sqe6fogK3XwVL11 6ay5PzVirJTc4+8pFw69p8QH2lf7cuPv+1oi0p2NzP3SuTAp4oYZJjlo1uRmVtkTBk4x 5GDhfjDTwNBy0Ss1ozccXzwtu0qUQJPJG7E4iChPnpX2l8VpslVFc+V8ZNmdnP1YS5Dn 5JJR7SdWFbb4C1BLtGYcGS8iN2Vvclx9DPCZTuYQ3LcPXYBxkFvq8qIdtHoJ+pUTd7Yg wLxA== X-Gm-Message-State: ANoB5pncfrnURkrhWQCsy2fLxNYonXmtnD3GHAfNT/QiiKGuRwk3szSX Bdj9UpIO7S9NkFpc1tAxmxRaYY/slPmqFw== X-Google-Smtp-Source: AA0mqf5u4PnImU/GuJx89BRNMuBvIicZVJbmh/uCR5QyCkVi0M0SMC9Vf+UCgU2ZJaAJvyGVAOgFyg== X-Received: by 2002:a05:600c:3d90:b0:3d1:fe93:f1db with SMTP id bi16-20020a05600c3d9000b003d1fe93f1dbmr12852325wmb.19.1670877063582; Mon, 12 Dec 2022 12:31:03 -0800 (PST) Received: from localhost ([2001:8a0:f912:6700:afd9:8b6d:223f:6170]) by smtp.gmail.com with ESMTPSA id h22-20020a05600c351600b003d21759db42sm11166988wmq.5.2022.12.12.12.31.03 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 12 Dec 2022 12:31:03 -0800 (PST) From: Pedro Alves To: gdb-patches@sourceware.org Subject: [PATCH 05/31] Support clone events in the remote protocol Date: Mon, 12 Dec 2022 20:30:35 +0000 Message-Id: <20221212203101.1034916-6-pedro@palves.net> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20221212203101.1034916-1-pedro@palves.net> References: <20221212203101.1034916-1-pedro@palves.net> MIME-Version: 1.0 X-Spam-Status: No, score=-10.1 required=5.0 tests=BAYES_00, FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM, GIT_PATCH_0, HEADER_FROM_DIFFERENT_DOMAINS, KAM_DMARC_STATUS, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) 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: , Errors-To: gdb-patches-bounces+patchwork=sourceware.org@sourceware.org Sender: "Gdb-patches" The previous patch taught GDB about a new TARGET_WAITKIND_THREAD_CLONED event kind, and made the Linux target report clone events. A following patch will teach Linux GDBserver to do the same thing. But before we get there, we need to teach the remote protocol about TARGET_WAITKIND_THREAD_CLONED. That's what this patch does. Clone is very similar to vfork and fork, and the new stop reply is likewise handled similarly. The stub reports "T05clone:...". GDBserver core is taught to handle TARGET_WAITKIND_THREAD_CLONED and forward it to GDB in this patch, but no backend actually emits it yet. That will be done in a following patch. Documentation for this new remote protocol feature is included in a documentation patch later in the series. Change-Id: If271f20320d864f074d8ac0d531cc1a323da847f Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=19675 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27830 Reviewed-By: Andrew Burgess --- gdb/remote.c | 99 ++++++++++++++++++++++++++------------- gdbserver/remote-utils.cc | 26 ++++++++-- gdbserver/server.cc | 3 +- 3 files changed, 91 insertions(+), 37 deletions(-) diff --git a/gdb/remote.c b/gdb/remote.c index 53c4f19c5a4..a7430eb79dd 100644 --- a/gdb/remote.c +++ b/gdb/remote.c @@ -672,6 +672,7 @@ class remote_target : public process_stratum_target const struct btrace_config *btrace_conf (const struct btrace_target_info *) override; bool augmented_libraries_svr4_read () override; void follow_fork (inferior *, ptid_t, target_waitkind, bool, bool) override; + void follow_clone (ptid_t child_ptid) override; void follow_exec (inferior *, ptid_t, const char *) override; int insert_fork_catchpoint (int) override; int remove_fork_catchpoint (int) override; @@ -765,7 +766,7 @@ class remote_target : public process_stratum_target void remote_btrace_maybe_reopen (); - void remove_new_fork_children (threads_listing_context *context); + void remove_new_children (threads_listing_context *context); void kill_new_fork_children (inferior *inf); void discard_pending_stop_replies (struct inferior *inf); int stop_reply_queue_length (); @@ -2579,9 +2580,10 @@ remote_target::remote_add_thread (ptid_t ptid, bool running, bool executing, else thread = add_thread (this, ptid); - /* We start by assuming threads are resumed. That state then gets updated - when we process a matching stop reply. */ - get_remote_thread_info (thread)->set_resumed (); + /* We start by assuming threads are resumed. That state then gets + updated when we process a matching stop reply. */ + if (executing) + get_remote_thread_info (thread)->set_resumed (); set_executing (this, ptid, executing); set_running (this, ptid, running); @@ -3983,10 +3985,11 @@ remote_target::update_thread_list () } } - /* Remove any unreported fork child threads from CONTEXT so - that we don't interfere with follow fork, which is where - creation of such threads is handled. */ - remove_new_fork_children (&context); + /* Remove any unreported fork/vfork/clone child threads from + CONTEXT so that we don't interfere with follow + fork/vfork/clone, which is where creation of such threads is + handled. */ + remove_new_children (&context); /* And now add threads we don't know about yet to our list. */ for (thread_item &item : context.items) @@ -4940,6 +4943,8 @@ remote_target::start_remote_1 (int from_tty, int extended_p) } else switch_to_thread (find_thread_ptid (this, curr_thread)); + + get_remote_thread_info (inferior_thread ())->set_resumed (); } /* init_wait_for_inferior should be called before get_offsets in order @@ -5893,16 +5898,25 @@ is_fork_status (target_waitkind kind) || kind == TARGET_WAITKIND_VFORKED); } -/* Return THREAD's pending status if it is a pending fork parent, else - return nullptr. */ +/* Return a reference to the field where a pending child status, if + there's one, is recorded. If there's no child event pending, the + returned waitstatus has TARGET_WAITKIND_IGNORE kind. */ + +static const target_waitstatus & +thread_pending_status (struct thread_info *thread) +{ + return (thread->has_pending_waitstatus () + ? thread->pending_waitstatus () + : thread->pending_follow); +} + +/* Return THREAD's pending status if it is a pending fork/vfork (but + not clone) parent, else return nullptr. */ static const target_waitstatus * thread_pending_fork_status (struct thread_info *thread) { - const target_waitstatus &ws - = (thread->has_pending_waitstatus () - ? thread->pending_waitstatus () - : thread->pending_follow); + const target_waitstatus &ws = thread_pending_status (thread); if (!is_fork_status (ws.kind ())) return nullptr; @@ -5910,6 +5924,20 @@ thread_pending_fork_status (struct thread_info *thread) return &ws; } +/* Return THREAD's pending status if is is a pending fork/vfork/clone + event, else return nullptr. */ + +static const target_waitstatus * +thread_pending_child_status (thread_info *thread) +{ + const target_waitstatus &ws = thread_pending_status (thread); + + if (!is_new_child_status (ws.kind ())) + return nullptr; + + return &ws; +} + /* Detach the specified process. */ void @@ -6075,6 +6103,12 @@ remote_target::follow_fork (inferior *child_inf, ptid_t child_ptid, } } +void +remote_target::follow_clone (ptid_t child_ptid) +{ + remote_add_thread (child_ptid, false, false, false); +} + /* Target follow-exec function for remote targets. Save EXECD_PATHNAME in the program space of the new inferior. */ @@ -6807,10 +6841,10 @@ remote_target::commit_resumed () if (priv->get_resume_state () == resume_state::RESUMED_PENDING_VCONT) any_pending_vcont_resume = true; - /* If a thread is the parent of an unfollowed fork, then we - can't do a global wildcard, as that would resume the fork - child. */ - if (thread_pending_fork_status (tp) != nullptr) + /* If a thread is the parent of an unfollowed fork/vfork/clone, + then we can't do a global wildcard, as that would resume the + pending child. */ + if (thread_pending_child_status (tp) != nullptr) may_global_wildcard_vcont = false; } @@ -7276,22 +7310,22 @@ struct notif_client notif_client_stop = REMOTE_NOTIF_STOP, }; -/* If CONTEXT contains any fork child threads that have not been - reported yet, remove them from the CONTEXT list. If such a - thread exists it is because we are stopped at a fork catchpoint - and have not yet called follow_fork, which will set up the - host-side data structures for the new process. */ +/* If CONTEXT contains any fork/vfork/clone child threads that have + not been reported yet, remove them from the CONTEXT list. If such + a thread exists it is because we are stopped at a fork/vfork/clone + catchpoint and have not yet called follow_fork/follow_clone, which + will set up the host-side data structures for the new child. */ void -remote_target::remove_new_fork_children (threads_listing_context *context) +remote_target::remove_new_children (threads_listing_context *context) { struct notif_client *notif = ¬if_client_stop; - /* For any threads stopped at a fork event, remove the corresponding - fork child threads from the CONTEXT list. */ + /* For any threads stopped at a (v)fork/clone event, remove the + corresponding child threads from the CONTEXT list. */ for (thread_info *thread : all_non_exited_threads (this)) { - const target_waitstatus *ws = thread_pending_fork_status (thread); + const target_waitstatus *ws = thread_pending_child_status (thread); if (ws == nullptr) continue; @@ -7299,13 +7333,12 @@ remote_target::remove_new_fork_children (threads_listing_context *context) context->remove_thread (ws->child_ptid ()); } - /* Check for any pending fork events (not reported or processed yet) - in process PID and remove those fork child threads from the - CONTEXT list as well. */ + /* Check for any pending (v)fork/clone events (not reported or + processed yet) in process PID and remove those child threads from + the CONTEXT list as well. */ remote_notif_get_pending_events (notif); for (auto &event : get_remote_state ()->stop_reply_queue) - if (event->ws.kind () == TARGET_WAITKIND_FORKED - || event->ws.kind () == TARGET_WAITKIND_VFORKED) + if (is_new_child_status (event->ws.kind ())) context->remove_thread (event->ws.child_ptid ()); else if (event->ws.kind () == TARGET_WAITKIND_THREAD_EXITED) context->remove_thread (event->ptid); @@ -7634,6 +7667,8 @@ Packet: '%s'\n"), event->ws.set_forked (read_ptid (++p1, &p)); else if (strprefix (p, p1, "vfork")) event->ws.set_vforked (read_ptid (++p1, &p)); + else if (strprefix (p, p1, "clone")) + event->ws.set_thread_cloned (read_ptid (++p1, &p)); else if (strprefix (p, p1, "vforkdone")) { event->ws.set_vfork_done (); diff --git a/gdbserver/remote-utils.cc b/gdbserver/remote-utils.cc index 2ddb275bd15..6a673cb1ca8 100644 --- a/gdbserver/remote-utils.cc +++ b/gdbserver/remote-utils.cc @@ -1062,6 +1062,7 @@ prepare_resume_reply (char *buf, ptid_t ptid, const target_waitstatus &status) case TARGET_WAITKIND_FORKED: case TARGET_WAITKIND_VFORKED: case TARGET_WAITKIND_VFORK_DONE: + case TARGET_WAITKIND_THREAD_CLONED: case TARGET_WAITKIND_EXECD: case TARGET_WAITKIND_THREAD_CREATED: case TARGET_WAITKIND_SYSCALL_ENTRY: @@ -1071,13 +1072,30 @@ prepare_resume_reply (char *buf, ptid_t ptid, const target_waitstatus &status) struct regcache *regcache; char *buf_start = buf; - if ((status.kind () == TARGET_WAITKIND_FORKED && cs.report_fork_events) + if ((status.kind () == TARGET_WAITKIND_FORKED + && cs.report_fork_events) || (status.kind () == TARGET_WAITKIND_VFORKED - && cs.report_vfork_events)) + && cs.report_vfork_events) + || status.kind () == TARGET_WAITKIND_THREAD_CLONED) { enum gdb_signal signal = GDB_SIGNAL_TRAP; - const char *event = (status.kind () == TARGET_WAITKIND_FORKED - ? "fork" : "vfork"); + + auto kind_remote_str = [] (target_waitkind kind) + { + switch (kind) + { + case TARGET_WAITKIND_FORKED: + return "fork"; + case TARGET_WAITKIND_VFORKED: + return "vfork"; + case TARGET_WAITKIND_THREAD_CLONED: + return "clone"; + default: + gdb_assert_not_reached ("unhandled kind"); + } + }; + + const char *event = kind_remote_str (status.kind ()); sprintf (buf, "T%02x%s:", signal, event); buf += strlen (buf); diff --git a/gdbserver/server.cc b/gdbserver/server.cc index aaef38e0062..56b7f97a388 100644 --- a/gdbserver/server.cc +++ b/gdbserver/server.cc @@ -236,7 +236,8 @@ in_queued_stop_replies_ptid (struct notif_event *event, ptid_t filter_ptid) /* Don't resume fork children that GDB does not know about yet. */ if ((vstop_event->status.kind () == TARGET_WAITKIND_FORKED - || vstop_event->status.kind () == TARGET_WAITKIND_VFORKED) + || vstop_event->status.kind () == TARGET_WAITKIND_VFORKED + || vstop_event->status.kind () == TARGET_WAITKIND_THREAD_CLONED) && vstop_event->status.child_ptid ().matches (filter_ptid)) return true;