From d83ad864a285fe3127e1a98830197e8461ad2745 Mon Sep 17 00:00:00 2001 From: Don Breazeal Date: Tue, 30 Sep 2014 11:01:57 -0700 Subject: [PATCH] Refactor native follow-fork. This patch reorganizes 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 contained 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, is 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. Although the order of some operations was changed, the resulting functionality was not. Modifications were made to the other native target follow-fork functions, inf_ttrace_follow_fork and inf_ptrace_follow_fork, that should allow them to work with follow_fork_inferior. Some other adjustments were necessary in inf-ttrace.c. The changes to inf-ttrace.c and inf-ptrace.c were not tested. gdb/ChangeLog: * inf-ptrace.c (inf_ptrace_follow_fork): Remove target-independent code so as to work with follow_fork_inferior. * inf-ttrace.c (inf_ttrace_follow_fork): Ditto. (inf_ttrace_create_inferior): Remove reference to inf_ttrace_vfork_ppid. (inf_ttrace_attach): Ditto. (inf_ttrace_detach): Ditto. (inf_ttrace_kill): Use current_inferior instead of inf_ttrace_vfork_ppid. (inf_ttrace_wait): Eliminate use of inf_ttrace_vfork_ppid, report TARGET_WAITKIND_VFORK_DONE event, delete HACK that switched the inferior away from the parent. * infrun.c (follow_fork): Call follow_fork_inferior instead of target_follow_fork. (follow_fork_inferior): New function. (follow_inferior_reset_breakpoints): Make function static. * infrun.h (follow_inferior_reset_breakpoints): Remove declaration. * linux-nat.c (linux_child_follow_fork): Move target-independent code to infrun.c:follow_fork_inferior. --- gdb/ChangeLog | 22 +++++ gdb/inf-ptrace.c | 48 ++------- gdb/inf-ttrace.c | 179 ++++------------------------------ gdb/infrun.c | 249 ++++++++++++++++++++++++++++++++++++++++++++++- gdb/infrun.h | 2 - gdb/linux-nat.c | 243 +++++---------------------------------------- 6 files changed, 320 insertions(+), 423 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index f3282144c30..c967a93dcb9 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,25 @@ +2014-09-30 Don Breazeal + + * inf-ptrace.c (inf_ptrace_follow_fork): Remove target-independent + code so as to work with follow_fork_inferior. + * inf-ttrace.c (inf_ttrace_follow_fork): Ditto. + (inf_ttrace_create_inferior): Remove reference to + inf_ttrace_vfork_ppid. + (inf_ttrace_attach): Ditto. + (inf_ttrace_detach): Ditto. + (inf_ttrace_kill): Use current_inferior instead of + inf_ttrace_vfork_ppid. + (inf_ttrace_wait): Eliminate use of inf_ttrace_vfork_ppid, report + TARGET_WAITKIND_VFORK_DONE event, delete HACK that switched the + inferior away from the parent. + * infrun.c (follow_fork): Call follow_fork_inferior instead of + target_follow_fork. + (follow_fork_inferior): New function. + (follow_inferior_reset_breakpoints): Make function static. + * infrun.h (follow_inferior_reset_breakpoints): Remove declaration. + * linux-nat.c (linux_child_follow_fork): Move target-independent + code to infrun.c:follow_fork_inferior. + 2014-09-30 Andreas Arnez * gdbarch.sh (regset_from_core_section): Remove gdbarch method. diff --git a/gdb/inf-ptrace.c b/gdb/inf-ptrace.c index dd71b3abc37..6eb80802423 100644 --- a/gdb/inf-ptrace.c +++ b/gdb/inf-ptrace.c @@ -36,57 +36,21 @@ #ifdef PT_GET_PROCESS_STATE +/* Target hook for follow_fork. On entry and at return inferior_ptid is + the ptid of the followed inferior. */ + static int inf_ptrace_follow_fork (struct target_ops *ops, int follow_child, int detach_fork) { - pid_t pid, fpid; - ptrace_state_t pe; - - pid = ptid_get_pid (inferior_ptid); - - if (ptrace (PT_GET_PROCESS_STATE, pid, - (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1) - perror_with_name (("ptrace")); - - gdb_assert (pe.pe_report_event == PTRACE_FORK); - fpid = pe.pe_other_pid; - - if (follow_child) + if (!follow_child) { - struct inferior *parent_inf, *child_inf; - struct thread_info *tp; - - parent_inf = find_inferior_pid (pid); - - /* Add the child. */ - child_inf = add_inferior (fpid); - child_inf->attach_flag = parent_inf->attach_flag; - copy_terminal_info (child_inf, parent_inf); - child_inf->pspace = parent_inf->pspace; - child_inf->aspace = parent_inf->aspace; + pid_t child_pid = inferior_thread->pending_follow.value.related_pid; - /* Before detaching from the parent, remove all breakpoints from - it. */ - remove_breakpoints (); - - if (ptrace (PT_DETACH, pid, (PTRACE_TYPE_ARG3)1, 0) == -1) - perror_with_name (("ptrace")); - - /* Switch inferior_ptid out of the parent's way. */ - inferior_ptid = pid_to_ptid (fpid); - - /* Delete the parent. */ - detach_inferior (pid); - - add_thread_silent (inferior_ptid); - } - else - { /* Breakpoints have already been detached from the child by infrun.c. */ - if (ptrace (PT_DETACH, fpid, (PTRACE_TYPE_ARG3)1, 0) == -1) + if (ptrace (PT_DETACH, child_pid, (PTRACE_TYPE_ARG3)1, 0) == -1) perror_with_name (("ptrace")); } diff --git a/gdb/inf-ttrace.c b/gdb/inf-ttrace.c index 847beb3f675..dceea421b3a 100644 --- a/gdb/inf-ttrace.c +++ b/gdb/inf-ttrace.c @@ -403,128 +403,18 @@ inf_ttrace_stopped_by_watchpoint (struct target_ops *ops) } -/* When tracking a vfork(2), we cannot detach from the parent until - after the child has called exec(3) or has exited. If we are still - attached to the parent, this variable will be set to the process ID - of the parent. Otherwise it will be set to zero. */ -static pid_t inf_ttrace_vfork_ppid = -1; +/* Target hook for follow_fork. On entry and at return inferior_ptid + is the ptid of the followed inferior. */ static int inf_ttrace_follow_fork (struct target_ops *ops, int follow_child, int detach_fork) { - pid_t pid, fpid; - lwpid_t lwpid, flwpid; - ttstate_t tts; struct thread_info *tp = inferior_thread (); gdb_assert (tp->pending_follow.kind == TARGET_WAITKIND_FORKED || tp->pending_follow.kind == TARGET_WAITKIND_VFORKED); - pid = ptid_get_pid (inferior_ptid); - lwpid = ptid_get_lwp (inferior_ptid); - - /* Get all important details that core GDB doesn't (and shouldn't) - know about. */ - if (ttrace (TT_LWP_GET_STATE, pid, lwpid, - (uintptr_t)&tts, sizeof tts, 0) == -1) - perror_with_name (("ttrace")); - - gdb_assert (tts.tts_event == TTEVT_FORK || tts.tts_event == TTEVT_VFORK); - - if (tts.tts_u.tts_fork.tts_isparent) - { - pid = tts.tts_pid; - lwpid = tts.tts_lwpid; - fpid = tts.tts_u.tts_fork.tts_fpid; - flwpid = tts.tts_u.tts_fork.tts_flwpid; - } - else - { - pid = tts.tts_u.tts_fork.tts_fpid; - lwpid = tts.tts_u.tts_fork.tts_flwpid; - fpid = tts.tts_pid; - flwpid = tts.tts_lwpid; - } - - if (follow_child) - { - struct inferior *inf; - struct inferior *parent_inf; - - parent_inf = find_inferior_pid (pid); - - inferior_ptid = ptid_build (fpid, flwpid, 0); - inf = add_inferior (fpid); - inf->attach_flag = parent_inf->attach_flag; - inf->pspace = parent_inf->pspace; - inf->aspace = parent_inf->aspace; - copy_terminal_info (inf, parent_inf); - detach_breakpoints (ptid_build (pid, lwpid, 0)); - - target_terminal_ours (); - fprintf_unfiltered (gdb_stdlog, - _("Attaching after fork to child process %ld.\n"), - (long)fpid); - } - else - { - inferior_ptid = ptid_build (pid, lwpid, 0); - /* Detach any remaining breakpoints in the child. In the case - of fork events, we do not need to do this, because breakpoints - should have already been removed earlier. */ - if (tts.tts_event == TTEVT_VFORK) - detach_breakpoints (ptid_build (fpid, flwpid, 0)); - - target_terminal_ours (); - fprintf_unfiltered (gdb_stdlog, - _("Detaching after fork from child process %ld.\n"), - (long)fpid); - } - - if (tts.tts_event == TTEVT_VFORK) - { - gdb_assert (!tts.tts_u.tts_fork.tts_isparent); - - if (follow_child) - { - /* We can't detach from the parent yet. */ - inf_ttrace_vfork_ppid = pid; - - reattach_breakpoints (fpid); - } - else - { - if (ttrace (TT_PROC_DETACH, fpid, 0, 0, 0, 0) == -1) - perror_with_name (("ttrace")); - - /* Wait till we get the TTEVT_VFORK event in the parent. - This indicates that the child has called exec(3) or has - exited and that the parent is ready to be traced again. */ - if (ttrace_wait (pid, lwpid, TTRACE_WAITOK, &tts, sizeof tts) == -1) - perror_with_name (("ttrace_wait")); - gdb_assert (tts.tts_event == TTEVT_VFORK); - gdb_assert (tts.tts_u.tts_fork.tts_isparent); - - reattach_breakpoints (pid); - } - } - else - { - gdb_assert (tts.tts_u.tts_fork.tts_isparent); - - if (follow_child) - { - if (ttrace (TT_PROC_DETACH, pid, 0, 0, 0, 0) == -1) - perror_with_name (("ttrace")); - } - else - { - if (ttrace (TT_PROC_DETACH, fpid, 0, 0, 0, 0) == -1) - perror_with_name (("ttrace")); - } - } - if (follow_child) { struct thread_info *ti; @@ -533,17 +423,21 @@ inf_ttrace_follow_fork (struct target_ops *ops, int follow_child, inf_ttrace_num_lwps = 1; inf_ttrace_num_lwps_in_syscall = 0; - /* Delete parent. */ - delete_thread_silent (ptid_build (pid, lwpid, 0)); - detach_inferior (pid); - - /* Add child thread. inferior_ptid was already set above. */ - ti = add_thread_silent (inferior_ptid); + ti = inferior_thread (); ti->private = xmalloc (sizeof (struct inf_ttrace_private_thread_info)); memset (ti->private, 0, sizeof (struct inf_ttrace_private_thread_info)); } + else + { + pid_t child_pid; + + /* Following parent. Detach child now. */ + child_pid = ptid_get_pid (tp->pending_follow.value.related_pid); + if (ttrace (TT_PROC_DETACH, child_pid, 0, 0, 0, 0) == -1) + perror_with_name (("ttrace")); + } return 0; } @@ -661,7 +555,6 @@ inf_ttrace_create_inferior (struct target_ops *ops, char *exec_file, gdb_assert (inf_ttrace_num_lwps_in_syscall == 0); gdb_assert (inf_ttrace_page_dict.count == 0); gdb_assert (inf_ttrace_reenable_page_protections == 0); - gdb_assert (inf_ttrace_vfork_ppid == -1); pid = fork_inferior (exec_file, allargs, env, inf_ttrace_me, NULL, inf_ttrace_prepare, NULL, NULL); @@ -772,7 +665,6 @@ inf_ttrace_attach (struct target_ops *ops, const char *args, int from_tty) gdb_assert (inf_ttrace_num_lwps == 0); gdb_assert (inf_ttrace_num_lwps_in_syscall == 0); - gdb_assert (inf_ttrace_vfork_ppid == -1); if (ttrace (TT_PROC_ATTACH, pid, 0, TT_KILL_ON_EXIT, TT_VERSION, 0) == -1) perror_with_name (("ttrace")); @@ -822,13 +714,6 @@ inf_ttrace_detach (struct target_ops *ops, const char *args, int from_tty) if (ttrace (TT_PROC_DETACH, pid, 0, 0, sig, 0) == -1) perror_with_name (("ttrace")); - if (inf_ttrace_vfork_ppid != -1) - { - if (ttrace (TT_PROC_DETACH, inf_ttrace_vfork_ppid, 0, 0, 0, 0) == -1) - perror_with_name (("ttrace")); - inf_ttrace_vfork_ppid = -1; - } - inf_ttrace_num_lwps = 0; inf_ttrace_num_lwps_in_syscall = 0; @@ -850,13 +735,6 @@ inf_ttrace_kill (struct target_ops *ops) perror_with_name (("ttrace")); /* ??? Is it necessary to call ttrace_wait() here? */ - if (inf_ttrace_vfork_ppid != -1) - { - if (ttrace (TT_PROC_DETACH, inf_ttrace_vfork_ppid, 0, 0, 0, 0) == -1) - perror_with_name (("ttrace")); - inf_ttrace_vfork_ppid = -1; - } - target_mourn_inferior (); } @@ -967,20 +845,6 @@ inf_ttrace_wait (struct target_ops *ops, if (ttrace_wait (pid, lwpid, TTRACE_WAITOK, &tts, sizeof tts) == -1) perror_with_name (("ttrace_wait")); - if (tts.tts_event == TTEVT_VFORK && tts.tts_u.tts_fork.tts_isparent) - { - if (inf_ttrace_vfork_ppid != -1) - { - gdb_assert (inf_ttrace_vfork_ppid == tts.tts_pid); - - if (ttrace (TT_PROC_DETACH, tts.tts_pid, 0, 0, 0, 0) == -1) - perror_with_name (("ttrace")); - inf_ttrace_vfork_ppid = -1; - } - - tts.tts_event = TTEVT_NONE; - } - clear_sigint_trap (); } while (tts.tts_event == TTEVT_NONE); @@ -1075,17 +939,16 @@ inf_ttrace_wait (struct target_ops *ops, break; case TTEVT_VFORK: - gdb_assert (!tts.tts_u.tts_fork.tts_isparent); - - related_ptid = ptid_build (tts.tts_u.tts_fork.tts_fpid, - tts.tts_u.tts_fork.tts_flwpid, 0); - - ourstatus->kind = TARGET_WAITKIND_VFORKED; - ourstatus->value.related_pid = related_ptid; + if (tts.tts_u.tts_fork.tts_isparent) + ourstatus->kind = TARGET_WAITKIND_VFORK_DONE; + else + { + related_ptid = ptid_build (tts.tts_u.tts_fork.tts_fpid, + tts.tts_u.tts_fork.tts_flwpid, 0); - /* HACK: To avoid touching the parent during the vfork, switch - away from it. */ - inferior_ptid = ptid; + ourstatus->kind = TARGET_WAITKIND_VFORKED; + ourstatus->value.related_pid = related_ptid; + } break; case TTEVT_LWP_CREATE: diff --git a/gdb/infrun.c b/gdb/infrun.c index 5e123be0e0d..728c160bc7f 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); @@ -396,6 +401,241 @@ show_follow_fork_mode_string (struct ui_file *file, int from_tty, } +/* 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. On entry inferior_ptid must be the ptid of + the fork parent. At return inferior_ptid is the ptid of the + followed inferior. */ + +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 (e.g., 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 (e.g., 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 target_follow_fork (follow_child, detach_fork); +} + /* Tell the target to follow the fork we're stopped at. Returns true if the inferior should be resumed; false, if the target for some reason decided it's best not to resume. */ @@ -486,9 +726,10 @@ 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 refused to follow, or there's some other reason we shouldn't resume. */ @@ -560,7 +801,7 @@ follow_fork (void) return should_resume; } -void +static void follow_inferior_reset_breakpoints (void) { struct thread_info *tp = inferior_thread (); diff --git a/gdb/infrun.h b/gdb/infrun.h index cc9cb336954..fb6276b1c42 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 7f0f4f84bd3..60f6a848971 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" @@ -369,79 +368,41 @@ delete_lwp_cleanup (void *lp_voidp) delete_lwp (lp->ptid); } +/* Target hook for follow_fork. On entry inferior_ptid must be the + ptid of the followed inferior. At return, inferior_ptid will be + unchanged. */ + static int linux_child_follow_fork (struct target_ops *ops, 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) + if (!follow_child) { struct lwp_info *child_lp = NULL; + int status = W_STOPCODE (0); + struct cleanup *old_chain; + 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); + /* 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) @@ -476,86 +437,20 @@ holding the child stopped. Try \"set detach-on-fork\" or \ ptrace (PTRACE_DETACH, child_pid, 0, signo); } + /* Resets value of inferior_ptid to parent ptid. */ do_cleanups (old_chain); } 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 +523,12 @@ 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 (); } -- 2.30.2