gdb/testsuite/gdb.threads/pending-fork-event-detach.exp

   1 # Copyright (C) 2021 Free Software Foundation, Inc.
   2
   3 # This program is free software; you can redistribute it and/or modify
   4 # it under the terms of the GNU General Public License as published by
   5 # the Free Software Foundation; either version 3 of the License, or
   6 # (at your option) any later version.
   7 #
   8 # This program is distributed in the hope that it will be useful,
   9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 # GNU General Public License for more details.
  12 #
  13 # You should have received a copy of the GNU General Public License
  14 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15
  16 # Then, test that if we detach an inferior with a pending fork child, that
  17 # child is correctly detached and resumes execution normally.  There are two
  18 # kinds of "pending fork child" we test:
  19 #
  20 #   - resulting of a fork catchpoint: we stop at a fork catchpoint and detach.
  21 #   - resulting of an all-stop stop on top of a non-stop target, where a fork
  22 #     event is saved as a pending wait status.  To test this, we stepi a thread
  23 #     while another one forks.  The stepi generally completes at least as fast
  24 #     as the fork, so we have a chance that the stop due to the stepi being
  25 #     complete is shown to the user while the fork event is saved for later.
  26 #
  27 # To verify that the child process is detached and resumes execution, we have
  28 # it write a file on the filesystem.  If we don't see the file after a certain
  29 # delay, it means the child was likely not detached, and the test fails.
  30 #
  31 # At the same time, this tests that having this pending fork event does not
  32 # cause other problems in general.  For example, a buggy GDB / GDBserver combo
  33 # would notice the thread of the child process of the (still unprocessed) fork
  34 # event, and erroneously create a new inferior for it.  Once fixed, the child
  35 # process' thread is hidden by whoever holds the pending fork event.
  36
  37 standard_testfile .c -touch-file.c
  38
  39 set touch_file_bin $binfile-touch-file
  40
  41 if { [is_remote target] } {
  42     # If the target is remote, write the file in whatever the current working
  43     # directory is, with a somewhat unique name.
  44     set touch_file_path ${testfile}-flag
  45 } else {
  46     set touch_file_path [standard_output_file flag]
  47 }
  48
  49 set opts [list debug "additional_flags=-DTOUCH_FILE_PATH=\"$touch_file_path\""]
  50 if { [gdb_compile "$srcdir/$subdir/$srcfile2" $touch_file_bin executable $opts] != "" } {
  51     return
  52 }
  53
  54 proc do_test { target-non-stop who_forks fork_function stop_mode } {
  55     set opts [list \
  56         debug \
  57         "additional_flags=-DFORK_FUNCTION=$fork_function" \
  58         "additional_flags=-DTOUCH_FILE_BIN=\"$::touch_file_bin\""]
  59
  60     # WHO_FORKS says which of the main or other thread calls (v)fork.  The
  61     # thread that does not call (v)fork is the one who tries to step.
  62     if { $who_forks == "main" } {
  63         lappend opts "additional_flags=-DMAIN_THREAD_FORKS"
  64         set this_binfile ${::binfile}-main-${fork_function}
  65     } elseif { $who_forks == "other" } {
  66         lappend opts "additional_flags=-DOTHER_THREAD_FORKS"
  67         set this_binfile ${::binfile}-other-${fork_function}
  68     } else {
  69         error "invalid who_forks value: $who_forks"
  70     }
  71
  72     if { [gdb_compile_pthreads "$::srcdir/$::subdir/$::srcfile" $this_binfile executable $opts] != "" } {
  73         return
  74     }
  75
  76     remote_file target delete $::touch_file_path
  77     gdb_assert { ![remote_file target exists $::touch_file_path] } "file does not exist before test"
  78
  79     save_vars { ::GDBFLAGS } {
  80         append ::GDBFLAGS " -ex \"maintenance set target-non-stop ${target-non-stop}\""
  81         clean_restart $this_binfile
  82     }
  83
  84     if {![runto_main]} {
  85         fail "could not run to main"
  86         return
  87     }
  88
  89     # Run until breakpoint in the second thread.
  90     gdb_test "break break_here" "Breakpoint $::decimal.*"
  91     gdb_continue_to_breakpoint "thread started"
  92
  93     # Delete the breakpoint so the thread doesn't do a step-over.
  94     delete_breakpoints
  95
  96     # Let the forking thread make progress during the step.
  97     gdb_test "p release_forking_thread = 1" " = 1"
  98
  99     # There are two "pending fork child" modes we can test here:
 100     #
 101     #   - catch: set up a "catch fork" / "catch vfork" and run to it.
 102     #   - stepi: stepi the non-forking thread while the forking thread,
 103     #     well, forks.
 104     if { $stop_mode == "catch" } {
 105         gdb_test "catch fork"
 106         gdb_test "catch vfork"
 107         gdb_test "continue" "hit Catchpoint $::decimal.*fork.*"
 108     } elseif { $stop_mode == "stepi" } {
 109         # stepi the non-forking thread.
 110         gdb_test "stepi"
 111     } else {
 112         error "invalid stop_mode value: $stop_mode"
 113     }
 114
 115     # Make sure there's still a single inferior.
 116     gdb_test "info inferior" {\* 1 [^\r\n]+}
 117
 118     gdb_test "detach"
 119
 120     # After being detached, the fork child creates file ::TOUCH_FILE_PATH.
 121     # Seeing this file tells us the fork child was detached and executed
 122     # successfully.
 123     gdb_assert { [target_file_exists_with_timeout $::touch_file_path] } "file exists after detach"
 124
 125     # Don't leave random files on the target system.
 126     if { [is_remote target] } {
 127         remote_file target delete $::touch_file_path
 128     }
 129 }
 130
 131 foreach_with_prefix target-non-stop { auto on off } {
 132     foreach_with_prefix who_forks { main other } {
 133         foreach_with_prefix fork_function { fork vfork } {
 134             foreach_with_prefix stop_mode { stepi catch } {
 135                 do_test ${target-non-stop} $who_forks $fork_function $stop_mode
 136             }
 137         }
 138     }
 139 }