From 117539e6d505f75386de6ba1bbe0b82e7c8ef111 Mon Sep 17 00:00:00 2001 From: Kamil Rytarowski Date: Thu, 30 Apr 2020 16:13:33 +0200 Subject: [PATCH] Add support for NetBSD thread events (create, exit) Report LWP CREATE and LWP EXIT events and setup this on post_attach() and post_startup_inferior(). Stop reinitializing the list of recognized threads in update_thread_list(). Handle LWP CREATE and EXIT events in nbsd_nat_target::wait(). gdb/ChangeLog: * nbsd-nat.c (nbsd_enable_proc_events) (nbsd_nat_target::post_startup_inferior): Add. (nbsd_nat_target::post_attach): Call `nbsd_enable_proc_events'. (nbsd_nat_target::update_thread_list): Rewrite. (nbsd_nat_target::wait): Handle "PTRACE_LWP_EXIT" and "PTRACE_LWP_CREATE". * nbsd-nat.h (nbsd_nat_target::post_startup_inferior): Add. --- gdb/ChangeLog | 10 ++++++ gdb/nbsd-nat.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++-- gdb/nbsd-nat.h | 1 + 3 files changed, 90 insertions(+), 3 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index ede911f7ac..4f3b2680bb 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,13 @@ +2020-04-30 Kamil Rytarowski + + * nbsd-nat.c (nbsd_enable_proc_events) + (nbsd_nat_target::post_startup_inferior): Add. + (nbsd_nat_target::post_attach): Call `nbsd_enable_proc_events'. + (nbsd_nat_target::update_thread_list): Rewrite. + (nbsd_nat_target::wait): Handle "PTRACE_LWP_EXIT" and + "PTRACE_LWP_CREATE". + * nbsd-nat.h (nbsd_nat_target::post_startup_inferior): Add. + 2020-04-30 Philippe Waroquiers * stack.c (_initialize_stack): Remove duplicated creation of "frame" command and "f" alias. diff --git a/gdb/nbsd-nat.c b/gdb/nbsd-nat.c index b04e634b54..254a768eb3 100644 --- a/gdb/nbsd-nat.c +++ b/gdb/nbsd-nat.c @@ -222,11 +222,37 @@ nbsd_add_threads (nbsd_nat_target *target, pid_t pid) nbsd_thread_lister (pid, fn); } +/* Enable additional event reporting on new processes. */ + +static void +nbsd_enable_proc_events (pid_t pid) +{ + int events; + + if (ptrace (PT_GET_EVENT_MASK, pid, &events, sizeof (events)) == -1) + perror_with_name (("ptrace")); + + events |= PTRACE_LWP_CREATE; + events |= PTRACE_LWP_EXIT; + + if (ptrace (PT_SET_EVENT_MASK, pid, &events, sizeof (events)) == -1) + perror_with_name (("ptrace")); +} + +/* Implement the "post_startup_inferior" target_ops method. */ + +void +nbsd_nat_target::post_startup_inferior (ptid_t ptid) +{ + nbsd_enable_proc_events (ptid.pid ()); +} + /* Implement the "post_attach" target_ops method. */ void nbsd_nat_target::post_attach (int pid) { + nbsd_enable_proc_events (pid); nbsd_add_threads (this, pid); } @@ -235,9 +261,7 @@ nbsd_nat_target::post_attach (int pid) void nbsd_nat_target::update_thread_list () { - prune_threads (); - - nbsd_add_threads (this, inferior_ptid.pid ()); + delete_exited_threads (); } /* Convert PTID to a string. */ @@ -686,9 +710,61 @@ nbsd_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus, if (code <= SI_USER || code == SI_NOINFO) return wptid; + /* Process state for threading events */ + ptrace_state_t pst = {}; + if (code == TRAP_LWP) + { + if (ptrace (PT_GET_PROCESS_STATE, pid, &pst, sizeof (pst)) == -1) + perror_with_name (("ptrace")); + } + + if (code == TRAP_LWP && pst.pe_report_event == PTRACE_LWP_EXIT) + { + /* If GDB attaches to a multi-threaded process, exiting + threads might be skipped during post_attach that + have not yet reported their PTRACE_LWP_EXIT event. + Ignore exited events for an unknown LWP. */ + thread_info *thr = find_thread_ptid (this, wptid); + if (thr == nullptr) + ourstatus->kind = TARGET_WAITKIND_SPURIOUS; + else + { + ourstatus->kind = TARGET_WAITKIND_THREAD_EXITED; + /* NetBSD does not store an LWP exit status. */ + ourstatus->value.integer = 0; + + if (print_thread_events) + printf_unfiltered (_("[%s exited]\n"), + target_pid_to_str (wptid).c_str ()); + delete_thread (thr); + } + + /* The GDB core expects that the rest of the threads are running. */ + if (ptrace (PT_CONTINUE, pid, (void *) 1, 0) == -1) + perror_with_name (("ptrace")); + + return wptid; + } + if (in_thread_list (this, ptid_t (pid))) thread_change_ptid (this, ptid_t (pid), wptid); + if (code == TRAP_LWP && pst.pe_report_event == PTRACE_LWP_CREATE) + { + /* If GDB attaches to a multi-threaded process, newborn + threads might be added by nbsd_add_threads that have + not yet reported their PTRACE_LWP_CREATE event. Ignore + born events for an already-known LWP. */ + if (in_thread_list (this, wptid)) + ourstatus->kind = TARGET_WAITKIND_SPURIOUS; + else + { + add_thread (this, wptid); + ourstatus->kind = TARGET_WAITKIND_THREAD_CREATED; + } + return wptid; + } + if (code == TRAP_EXEC) { ourstatus->kind = TARGET_WAITKIND_EXECD; diff --git a/gdb/nbsd-nat.h b/gdb/nbsd-nat.h index 6e14cbb889..4a8b96026e 100644 --- a/gdb/nbsd-nat.h +++ b/gdb/nbsd-nat.h @@ -32,6 +32,7 @@ struct nbsd_nat_target : public inf_ptrace_target bool thread_alive (ptid_t ptid) override; const char *thread_name (struct thread_info *thr) override; + void post_startup_inferior (ptid_t ptid) override; void post_attach (int pid) override; void update_thread_list () override; std::string pid_to_str (ptid_t ptid) override; -- 2.34.1