From patchwork Thu Aug 21 00:29:09 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Don Breazeal X-Patchwork-Id: 2460 Received: (qmail 27914 invoked by alias); 21 Aug 2014 00:29:57 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 27885 invoked by uid 89); 21 Aug 2014 00:29:53 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.7 required=5.0 tests=AWL, BAYES_00 autolearn=ham version=3.3.2 X-HELO: relay1.mentorg.com Received: from relay1.mentorg.com (HELO relay1.mentorg.com) (192.94.38.131) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 21 Aug 2014 00:29:51 +0000 Received: from svr-orw-exc-10.mgc.mentorg.com ([147.34.98.58]) by relay1.mentorg.com with esmtp id 1XKGGB-0001Gm-Tf from donb@codesourcery.com for gdb-patches@sourceware.org; Wed, 20 Aug 2014 17:29:47 -0700 Received: from SVR-ORW-FEM-04.mgc.mentorg.com ([147.34.97.41]) by SVR-ORW-EXC-10.mgc.mentorg.com with Microsoft SMTPSVC(6.0.3790.4675); Wed, 20 Aug 2014 17:29:47 -0700 Received: from build4-lucid-cs (147.34.91.1) by svr-orw-fem-04.mgc.mentorg.com (147.34.97.41) with Microsoft SMTP Server id 14.2.247.3; Wed, 20 Aug 2014 17:29:47 -0700 Received: by build4-lucid-cs (Postfix, from userid 1905) id 119D140D74; Wed, 20 Aug 2014 17:29:46 -0700 (PDT) From: Don Breazeal To: Subject: [PATCH 01/16 v2] Refactor native follow-fork Date: Wed, 20 Aug 2014 17:29:09 -0700 Message-ID: <1408580964-27916-2-git-send-email-donb@codesourcery.com> In-Reply-To: <1407434395-19089-1-git-send-email-donb@codesourcery.com> References: <1407434395-19089-1-git-send-email-donb@codesourcery.com> MIME-Version: 1.0 X-IsSubscribed: yes This patch reorganizes some of the code that implements follow-fork and detach-on-fork in preparation for implementation of those features for the extended-remote target. The function linux-nat.c:linux_child_follow_fork contains target-independent code mixed in with target-dependent code. The target-independent pieces need to be accessible for the host-side implementation of follow-fork for extended-remote Linux targets. The changes are fairly mechanical. A new routine, follow_fork_inferior, was implemented in infrun.c, containing those parts of linux_child_follow_fork that manage inferiors and the inferior list. The parts of linux_child_follow_fork that deal with LWPs and target-specifics were left in-place. Once the target-independent pieces were removed from linux_child_follow_fork, it was possible to consolidate it a bit. Although the order of some operations was changed, the resulting functionality was not. Tested on x64 Ubuntu Lucid, native only. Thanks, --Don gdb/ 2014-08-20 Don Breazeal * infrun.c (follow_fork): Call follow_fork_inferior. (follow_fork_inferior): New function. (follow_inferior_reset_breakpoints): Make function static. * infrun.h: Remove declaration of follow_inferior_reset_breakpoints. * linux-nat.c (linux_child_follow_fork): Move target-independent code to infrun.c:follow_fork_inferior. --- gdb/infrun.c | 248 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- gdb/infrun.h | 2 - gdb/linux-nat.c | 216 ++--------------------------------------------- 3 files changed, 254 insertions(+), 212 deletions(-) diff --git a/gdb/infrun.c b/gdb/infrun.c index c18267f..a51c759 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -60,6 +60,7 @@ #include "completer.h" #include "target-descriptions.h" #include "target-dcache.h" +#include "terminal.h" /* Prototypes for local functions */ @@ -79,6 +80,10 @@ static int restore_selected_frame (void *); static int follow_fork (void); +static int follow_fork_inferior (int follow_child, int detach_fork); + +static void follow_inferior_reset_breakpoints (void); + static void set_schedlock_func (char *args, int from_tty, struct cmd_list_element *c); @@ -486,9 +491,11 @@ follow_fork (void) parent = inferior_ptid; child = tp->pending_follow.value.related_pid; - /* Tell the target to do whatever is necessary to follow - either parent or child. */ - if (target_follow_fork (follow_child, detach_fork)) + /* Set up inferior(s) as specified by the caller, and tell the + target to do whatever is necessary to follow either parent + or child. */ + if (follow_fork_inferior (follow_child, detach_fork) + || target_follow_fork (follow_child, detach_fork)) { /* Target refused to follow, or there's some other reason we shouldn't resume. */ @@ -560,7 +567,240 @@ follow_fork (void) return should_resume; } -void +/* Handle changes to the inferior list based on the type of fork, + which process is being followed, and whether the other process + should be detached. */ + +static int +follow_fork_inferior (int follow_child, int detach_fork) +{ + int has_vforked; + int parent_pid, child_pid; + + has_vforked = (inferior_thread ()->pending_follow.kind + == TARGET_WAITKIND_VFORKED); + parent_pid = ptid_get_lwp (inferior_ptid); + if (parent_pid == 0) + parent_pid = ptid_get_pid (inferior_ptid); + child_pid + = ptid_get_pid (inferior_thread ()->pending_follow.value.related_pid); + + if (has_vforked + && !non_stop /* Non-stop always resumes both branches. */ + && (!target_is_async_p () || sync_execution) + && !(follow_child || detach_fork || sched_multi)) + { + /* The parent stays blocked inside the vfork syscall until the + child execs or exits. If we don't let the child run, then + the parent stays blocked. If we're telling the parent to run + in the foreground, the user will not be able to ctrl-c to get + back the terminal, effectively hanging the debug session. */ + fprintf_filtered (gdb_stderr, _("\ +Can not resume the parent process over vfork in the foreground while\n\ +holding the child stopped. Try \"set detach-on-fork\" or \ +\"set schedule-multiple\".\n")); + /* FIXME output string > 80 columns. */ + return 1; + } + + if (!follow_child) + { + /* Detach new forked process? */ + if (detach_fork) + { + struct cleanup *old_chain; + + /* Before detaching from the child, remove all breakpoints + from it. If we forked, then this has already been taken + care of by infrun.c. If we vforked however, any + breakpoint inserted in the parent is visible in the + child, even those added while stopped in a vfork + catchpoint. This will remove the breakpoints from the + parent also, but they'll be reinserted below. */ + if (has_vforked) + { + /* Keep breakpoints list in sync. */ + remove_breakpoints_pid (ptid_get_pid (inferior_ptid)); + } + + if (info_verbose || debug_infrun) + { + target_terminal_ours (); + fprintf_filtered (gdb_stdlog, + "Detaching after fork from " + "child process %d.\n", + child_pid); + } + } + else + { + struct inferior *parent_inf, *child_inf; + struct cleanup *old_chain; + + /* Add process to GDB's tables. */ + child_inf = add_inferior (child_pid); + + parent_inf = current_inferior (); + child_inf->attach_flag = parent_inf->attach_flag; + copy_terminal_info (child_inf, parent_inf); + child_inf->gdbarch = parent_inf->gdbarch; + copy_inferior_target_desc_info (child_inf, parent_inf); + + old_chain = save_inferior_ptid (); + save_current_program_space (); + + inferior_ptid = ptid_build (child_pid, child_pid, 0); + add_thread (inferior_ptid); + child_inf->symfile_flags = SYMFILE_NO_READ; + + /* If this is a vfork child, then the address-space is + shared with the parent. */ + if (has_vforked) + { + child_inf->pspace = parent_inf->pspace; + child_inf->aspace = parent_inf->aspace; + + /* The parent will be frozen until the child is done + with the shared region. Keep track of the + parent. */ + child_inf->vfork_parent = parent_inf; + child_inf->pending_detach = 0; + parent_inf->vfork_child = child_inf; + parent_inf->pending_detach = 0; + } + else + { + child_inf->aspace = new_address_space (); + child_inf->pspace = add_program_space (child_inf->aspace); + child_inf->removable = 1; + set_current_program_space (child_inf->pspace); + clone_program_space (child_inf->pspace, parent_inf->pspace); + + /* Let the shared library layer (solib-svr4) learn about + this new process, relocate the cloned exec, pull in + shared libraries, and install the solib event + breakpoint. If a "cloned-VM" event was propagated + better throughout the core, this wouldn't be + required. */ + solib_create_inferior_hook (0); + } + + do_cleanups (old_chain); + } + + if (has_vforked) + { + struct inferior *parent_inf; + + parent_inf = current_inferior (); + + /* If we detached from the child, then we have to be careful + to not insert breakpoints in the parent until the child + is done with the shared memory region. However, if we're + staying attached to the child, then we can and should + insert breakpoints, so that we can debug it. A + subsequent child exec or exit is enough to know when does + the child stops using the parent's address space. */ + parent_inf->waiting_for_vfork_done = detach_fork; + parent_inf->pspace->breakpoints_not_allowed = detach_fork; + } + } + else + { + /* Follow the child. */ + struct inferior *parent_inf, *child_inf; + struct program_space *parent_pspace; + + if (info_verbose || debug_infrun) + { + target_terminal_ours (); + if (has_vforked) + fprintf_filtered (gdb_stdlog, + _("Attaching after process %d " + "vfork to child process %d.\n"), + parent_pid, child_pid); + else + fprintf_filtered (gdb_stdlog, + _("Attaching after process %d " + "fork to child process %d.\n"), + parent_pid, child_pid); + } + + /* Add the new inferior first, so that the target_detach below + doesn't unpush the target. */ + + child_inf = add_inferior (child_pid); + + parent_inf = current_inferior (); + child_inf->attach_flag = parent_inf->attach_flag; + copy_terminal_info (child_inf, parent_inf); + child_inf->gdbarch = parent_inf->gdbarch; + copy_inferior_target_desc_info (child_inf, parent_inf); + + parent_pspace = parent_inf->pspace; + + /* If we're vforking, we want to hold on to the parent until the + child exits or execs. At child exec or exit time we can + remove the old breakpoints from the parent and detach or + resume debugging it. Otherwise, detach the parent now; we'll + want to reuse it's program/address spaces, but we can't set + them to the child before removing breakpoints from the + parent, otherwise, the breakpoints module could decide to + remove breakpoints from the wrong process (since they'd be + assigned to the same address space). */ + + if (has_vforked) + { + gdb_assert (child_inf->vfork_parent == NULL); + gdb_assert (parent_inf->vfork_child == NULL); + child_inf->vfork_parent = parent_inf; + child_inf->pending_detach = 0; + parent_inf->vfork_child = child_inf; + parent_inf->pending_detach = detach_fork; + parent_inf->waiting_for_vfork_done = 0; + } + else if (detach_fork) + target_detach (NULL, 0); + + /* Note that the detach above makes PARENT_INF dangling. */ + + /* Add the child thread to the appropriate lists, and switch to + this new thread, before cloning the program space, and + informing the solib layer about this new process. */ + + inferior_ptid = ptid_build (child_pid, child_pid, 0); + add_thread (inferior_ptid); + + /* If this is a vfork child, then the address-space is shared + with the parent. If we detached from the parent, then we can + reuse the parent's program/address spaces. */ + if (has_vforked || detach_fork) + { + child_inf->pspace = parent_pspace; + child_inf->aspace = child_inf->pspace->aspace; + } + else + { + child_inf->aspace = new_address_space (); + child_inf->pspace = add_program_space (child_inf->aspace); + child_inf->removable = 1; + child_inf->symfile_flags = SYMFILE_NO_READ; + set_current_program_space (child_inf->pspace); + clone_program_space (child_inf->pspace, parent_pspace); + + /* Let the shared library layer (solib-svr4) learn about + this new process, relocate the cloned exec, pull in + shared libraries, and install the solib event breakpoint. + If a "cloned-VM" event was propagated better throughout + the core, this wouldn't be required. */ + solib_create_inferior_hook (0); + } + } + + return 0; +} + +static void follow_inferior_reset_breakpoints (void) { struct thread_info *tp = inferior_thread (); diff --git a/gdb/infrun.h b/gdb/infrun.h index cc9cb33..fb6276b 100644 --- a/gdb/infrun.h +++ b/gdb/infrun.h @@ -115,8 +115,6 @@ extern void insert_step_resume_breakpoint_at_sal (struct gdbarch *, struct symtab_and_line , struct frame_id); -extern void follow_inferior_reset_breakpoints (void); - /* Returns true if we're trying to step past the instruction at ADDRESS in ASPACE. */ extern int stepping_past_instruction_at (struct address_space *aspace, diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c index 1e8991d..ab287bf 100644 --- a/gdb/linux-nat.c +++ b/gdb/linux-nat.c @@ -54,7 +54,6 @@ #include #include #include "xml-support.h" -#include "terminal.h" #include #include "solib.h" #include "nat/linux-osdata.h" @@ -384,64 +383,22 @@ linux_child_follow_fork (struct target_ops *ops, int follow_child, child_pid = ptid_get_pid (inferior_thread ()->pending_follow.value.related_pid); - if (has_vforked - && !non_stop /* Non-stop always resumes both branches. */ - && (!target_is_async_p () || sync_execution) - && !(follow_child || detach_fork || sched_multi)) - { - /* The parent stays blocked inside the vfork syscall until the - child execs or exits. If we don't let the child run, then - the parent stays blocked. If we're telling the parent to run - in the foreground, the user will not be able to ctrl-c to get - back the terminal, effectively hanging the debug session. */ - fprintf_filtered (gdb_stderr, _("\ -Can not resume the parent process over vfork in the foreground while\n\ -holding the child stopped. Try \"set detach-on-fork\" or \ -\"set schedule-multiple\".\n")); - /* FIXME output string > 80 columns. */ - return 1; - } - - if (! follow_child) + if (!follow_child) { struct lwp_info *child_lp = NULL; + int status = W_STOPCODE (0); + struct cleanup *old_chain; /* We're already attached to the parent, by default. */ + old_chain = save_inferior_ptid (); + inferior_ptid = ptid_build (child_pid, child_pid, 0); + child_lp = add_lwp (inferior_ptid); + child_lp->stopped = 1; + child_lp->last_resume_kind = resume_stop; /* Detach new forked process? */ if (detach_fork) { - struct cleanup *old_chain; - int status = W_STOPCODE (0); - - /* Before detaching from the child, remove all breakpoints - from it. If we forked, then this has already been taken - care of by infrun.c. If we vforked however, any - breakpoint inserted in the parent is visible in the - child, even those added while stopped in a vfork - catchpoint. This will remove the breakpoints from the - parent also, but they'll be reinserted below. */ - if (has_vforked) - { - /* keep breakpoints list in sync. */ - remove_breakpoints_pid (ptid_get_pid (inferior_ptid)); - } - - if (info_verbose || debug_linux_nat) - { - target_terminal_ours (); - fprintf_filtered (gdb_stdlog, - "Detaching after fork from " - "child process %d.\n", - child_pid); - } - - old_chain = save_inferior_ptid (); - inferior_ptid = ptid_build (child_pid, child_pid, 0); - - child_lp = add_lwp (inferior_ptid); - child_lp->stopped = 1; - child_lp->last_resume_kind = resume_stop; make_cleanup (delete_lwp_cleanup, child_lp); if (linux_nat_prepare_to_resume != NULL) @@ -480,82 +437,15 @@ holding the child stopped. Try \"set detach-on-fork\" or \ } else { - struct inferior *parent_inf, *child_inf; - struct cleanup *old_chain; - - /* Add process to GDB's tables. */ - child_inf = add_inferior (child_pid); - - parent_inf = current_inferior (); - child_inf->attach_flag = parent_inf->attach_flag; - copy_terminal_info (child_inf, parent_inf); - child_inf->gdbarch = parent_inf->gdbarch; - copy_inferior_target_desc_info (child_inf, parent_inf); - - old_chain = save_inferior_ptid (); - save_current_program_space (); - - inferior_ptid = ptid_build (child_pid, child_pid, 0); - add_thread (inferior_ptid); - child_lp = add_lwp (inferior_ptid); - child_lp->stopped = 1; - child_lp->last_resume_kind = resume_stop; - child_inf->symfile_flags = SYMFILE_NO_READ; - - /* If this is a vfork child, then the address-space is - shared with the parent. */ - if (has_vforked) - { - child_inf->pspace = parent_inf->pspace; - child_inf->aspace = parent_inf->aspace; - - /* The parent will be frozen until the child is done - with the shared region. Keep track of the - parent. */ - child_inf->vfork_parent = parent_inf; - child_inf->pending_detach = 0; - parent_inf->vfork_child = child_inf; - parent_inf->pending_detach = 0; - } - else - { - child_inf->aspace = new_address_space (); - child_inf->pspace = add_program_space (child_inf->aspace); - child_inf->removable = 1; - set_current_program_space (child_inf->pspace); - clone_program_space (child_inf->pspace, parent_inf->pspace); - - /* Let the shared library layer (solib-svr4) learn about - this new process, relocate the cloned exec, pull in - shared libraries, and install the solib event - breakpoint. If a "cloned-VM" event was propagated - better throughout the core, this wouldn't be - required. */ - solib_create_inferior_hook (0); - } - /* Let the thread_db layer learn about this new process. */ check_for_thread_db (); - - do_cleanups (old_chain); } + do_cleanups (old_chain); + if (has_vforked) { struct lwp_info *parent_lp; - struct inferior *parent_inf; - - parent_inf = current_inferior (); - - /* If we detached from the child, then we have to be careful - to not insert breakpoints in the parent until the child - is done with the shared memory region. However, if we're - staying attached to the child, then we can and should - insert breakpoints, so that we can debug it. A - subsequent child exec or exit is enough to know when does - the child stops using the parent's address space. */ - parent_inf->waiting_for_vfork_done = detach_fork; - parent_inf->pspace->breakpoints_not_allowed = detach_fork; parent_lp = find_lwp_pid (pid_to_ptid (parent_pid)); gdb_assert (linux_supports_tracefork () >= 0); @@ -628,98 +518,12 @@ holding the child stopped. Try \"set detach-on-fork\" or \ } else { - struct inferior *parent_inf, *child_inf; struct lwp_info *child_lp; - struct program_space *parent_pspace; - - if (info_verbose || debug_linux_nat) - { - target_terminal_ours (); - if (has_vforked) - fprintf_filtered (gdb_stdlog, - _("Attaching after process %d " - "vfork to child process %d.\n"), - parent_pid, child_pid); - else - fprintf_filtered (gdb_stdlog, - _("Attaching after process %d " - "fork to child process %d.\n"), - parent_pid, child_pid); - } - - /* Add the new inferior first, so that the target_detach below - doesn't unpush the target. */ - - child_inf = add_inferior (child_pid); - - parent_inf = current_inferior (); - child_inf->attach_flag = parent_inf->attach_flag; - copy_terminal_info (child_inf, parent_inf); - child_inf->gdbarch = parent_inf->gdbarch; - copy_inferior_target_desc_info (child_inf, parent_inf); - - parent_pspace = parent_inf->pspace; - - /* If we're vforking, we want to hold on to the parent until the - child exits or execs. At child exec or exit time we can - remove the old breakpoints from the parent and detach or - resume debugging it. Otherwise, detach the parent now; we'll - want to reuse it's program/address spaces, but we can't set - them to the child before removing breakpoints from the - parent, otherwise, the breakpoints module could decide to - remove breakpoints from the wrong process (since they'd be - assigned to the same address space). */ - - if (has_vforked) - { - gdb_assert (child_inf->vfork_parent == NULL); - gdb_assert (parent_inf->vfork_child == NULL); - child_inf->vfork_parent = parent_inf; - child_inf->pending_detach = 0; - parent_inf->vfork_child = child_inf; - parent_inf->pending_detach = detach_fork; - parent_inf->waiting_for_vfork_done = 0; - } - else if (detach_fork) - target_detach (NULL, 0); - /* Note that the detach above makes PARENT_INF dangling. */ - - /* Add the child thread to the appropriate lists, and switch to - this new thread, before cloning the program space, and - informing the solib layer about this new process. */ - - inferior_ptid = ptid_build (child_pid, child_pid, 0); - add_thread (inferior_ptid); child_lp = add_lwp (inferior_ptid); child_lp->stopped = 1; child_lp->last_resume_kind = resume_stop; - /* If this is a vfork child, then the address-space is shared - with the parent. If we detached from the parent, then we can - reuse the parent's program/address spaces. */ - if (has_vforked || detach_fork) - { - child_inf->pspace = parent_pspace; - child_inf->aspace = child_inf->pspace->aspace; - } - else - { - child_inf->aspace = new_address_space (); - child_inf->pspace = add_program_space (child_inf->aspace); - child_inf->removable = 1; - child_inf->symfile_flags = SYMFILE_NO_READ; - set_current_program_space (child_inf->pspace); - clone_program_space (child_inf->pspace, parent_pspace); - - /* Let the shared library layer (solib-svr4) learn about - this new process, relocate the cloned exec, pull in - shared libraries, and install the solib event breakpoint. - If a "cloned-VM" event was propagated better throughout - the core, this wouldn't be required. */ - solib_create_inferior_hook (0); - } - /* Let the thread_db layer learn about this new process. */ check_for_thread_db (); }