gdb/testsuite/gdb.threads/process-dies-while-detaching.exp

   1 # Copyright 2016-2022 Free Software Foundation, Inc.
   2 # This program is free software; you can redistribute it and/or modify
   3 # it under the terms of the GNU General Public License as published by
   4 # the Free Software Foundation; either version 3 of the License, or
   5 # (at your option) any later version.
   6 #
   7 # This program is distributed in the hope that it will be useful,
   8 # but WITHOUT ANY WARRANTY; without even the implied warranty of
   9 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10 # GNU General Public License for more details.
  11 #
  12 # You should have received a copy of the GNU General Public License
  13 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  14
  15 # This test spawns a few threads that immediately exit the whole
  16 # process.  On targets where the debugger needs to detach from each
  17 # thread individually (such as on the Linux kernel), the debugger must
  18 # handle the case of the process exiting while the detach is ongoing.
  19 #
  20 # Similarly, the process can also be killed from outside the debugger
  21 # (e.g., with SIGKILL), _before_ the user requests a detach.  The
  22 # debugger must likewise detach gracefully.
  23 #
  24 # The testcase actually builds two variants of the test program:
  25 # single-process, and multi-process.  In the multi-process variant,
  26 # the test program forks, and it's the fork child that spawns threads
  27 # that exit just while the process is being detached from.  The fork
  28 # parent waits for its child to exit, so if GDB fails to detach from
  29 # the child correctly, the parent hangs.  Because continuing the
  30 # parent can mask failure to detach from the child correctly (e.g.,
  31 # due to waitpid(-1,...) calls deep in the target layers managing to
  32 # reap the child), we try immediately detaching from the parent too,
  33 # and observing whether the parent exits via standard output.
  34 #
  35 # Normally, if testing with "target remote" against gdbserver, then
  36 # after detaching from all attached processes, gdbserver exits.
  37 # However, when gdbserver detaches from a process that is its own
  38 # direct child, gdbserver does not exit immediately.  Instead it
  39 # "joins" (waits for) the child, only exiting when the child itself
  40 # exits too.  Thus, on Linux, if gdbserver fails to detach from the
  41 # zombie child's threads correctly (or rather, reap them), it'll hang,
  42 # because the leader thread will only return an exit status after all
  43 # threads are reaped.  We test that as well.
  44
  45 standard_testfile
  46
  47 # Test that GDBserver exits.
  48
  49 proc test_server_exit {} {
  50     global server_spawn_id
  51
  52     set test "server exits"
  53     gdb_expect {
  54         -i $server_spawn_id
  55         eof {
  56             pass $test
  57             wait -i $server_spawn_id
  58             unset server_spawn_id
  59         }
  60         timeout {
  61             fail "$test (timeout)"
  62         }
  63     }
  64 }
  65
  66 # If RESULT is not zero, make the caller return.
  67
  68 proc return_if_fail { result } {
  69     if {$result != 0} {
  70         return -code return
  71     }
  72 }
  73
  74 # Detach from a process, and ensure that it exits after detaching.
  75 # This relies on inferior I/O.  INF_OUTPUT_RE is the pattern that
  76 # matches the expected inferior output.
  77
  78 proc detach_and_expect_exit {inf_output_re test} {
  79     global decimal
  80     global gdb_spawn_id
  81     global inferior_spawn_id
  82     global gdb_prompt
  83
  84     return_if_fail [gdb_test_multiple "detach" $test {
  85         -re "Detaching from .*, process $decimal" {
  86         }
  87     }]
  88
  89     # Use an indirect spawn id list, and remove inferior spawn id from
  90     # the expected output as soon as it matches, so that if
  91     # $inf_inferior_spawn_id is $server_spawn_id and we're testing in
  92     # "target remote" mode, the eof caused by gdbserver exiting is
  93     # left for the caller to handle.
  94     global daee_spawn_id_list
  95     set daee_spawn_id_list "$inferior_spawn_id $gdb_spawn_id"
  96
  97     set saw_prompt 0
  98     set saw_inf_exit 0
  99     while { !$saw_prompt || ! $saw_inf_exit } {
 100         # We don't know what order the interesting things will arrive in.
 101         # Using a pattern of the form 'x|y|z' instead of -re x ... -re y
 102         # ... -re z ensures that expect always chooses the match that
 103         # occurs leftmost in the input, and not the pattern appearing
 104         # first in the script that occurs anywhere in the input, so that
 105         # we don't skip anything.
 106         return_if_fail [gdb_test_multiple "" $test {
 107             -i daee_spawn_id_list
 108             -re "($inf_output_re)|($gdb_prompt )" {
 109                 if {[info exists expect_out(1,string)]} {
 110                     verbose -log "saw inferior exit"
 111                     set saw_inf_exit 1
 112                     set daee_spawn_id_list "$gdb_spawn_id"
 113                 } elseif {[info exists expect_out(2,string)]} {
 114                     verbose -log "saw prompt"
 115                     set saw_prompt 1
 116                     set daee_spawn_id_list "$inferior_spawn_id"
 117                 }
 118                 array unset expect_out
 119             }
 120         }]
 121     }
 122
 123     pass $test
 124 }
 125
 126 # Run to _exit in the child.
 127
 128 proc continue_to_exit_bp {} {
 129     gdb_breakpoint "_exit" temporary
 130     gdb_continue_to_breakpoint "_exit" ".*_exit.*"
 131 }
 132
 133 # If testing single-process, simply detach from the process.
 134 #
 135 # If testing multi-process, first detach from the child, then detach
 136 # from the parent and confirm that the parent exits, thus ensuring
 137 # we've detached from the child successfully, as the parent hangs in
 138 # its waitpid call otherwise.
 139 #
 140 # If connected with "target remote", make sure gdbserver exits.
 141 #
 142 # CMD indicates what to do with the parent after detaching the child.
 143 # Can be either "detach" to detach, or "continue", to continue to
 144 # exit.
 145 #
 146 # CHILD_EXIT indicates how is the child expected to exit.  Can be
 147 # either "normal" for normal exit, or "signal" for killed with signal
 148 # SIGKILL.
 149 #
 150 proc do_detach {multi_process cmd child_exit} {
 151     global decimal
 152     global server_spawn_id
 153
 154     if {$child_exit == "normal"} {
 155         set continue_re "exited normally.*"
 156         set inf_output_re "exited, status=0"
 157     } elseif {$child_exit == "signal"} {
 158         if {$multi_process} {
 159             set continue_re "exited with code 02.*"
 160         } else {
 161             set continue_re "terminated with signal SIGKILL.*"
 162         }
 163         set inf_output_re "signaled, sig=9"
 164     } else {
 165         error "unhandled \$child_exit: $child_exit"
 166     }
 167
 168     set is_remote [expr {[target_info exists gdb_protocol]
 169                          && [target_info gdb_protocol] == "remote"}]
 170
 171     if {$multi_process} {
 172         gdb_test "detach" "Detaching from .*, process $decimal\r\n\\\[Inferior $decimal \\(.*\\) detached\\\]" \
 173             "detach child"
 174
 175         gdb_test "inferior 1" "\[Switching to inferior $decimal\].*" \
 176             "switch to parent"
 177
 178         if {$cmd == "detach"} {
 179             # Make sure that detach works and that the parent process
 180             # exits cleanly.
 181             detach_and_expect_exit $inf_output_re "detach parent"
 182         } elseif {$cmd == "continue"} {
 183             # Make sure that continuing works and that the parent process
 184             # exits cleanly.
 185             gdb_test "continue" $continue_re
 186         } else {
 187             perror "unhandled command: $cmd"
 188         }
 189     } else {
 190         if $is_remote {
 191             set extra "\r\nEnding remote debugging\."
 192         } else {
 193             set extra ""
 194         }
 195         if {$cmd == "detach"} {
 196             gdb_test "detach" "Detaching from .*, process ${decimal}\r\n\\\[Inferior $decimal \\(.*\\) detached\\\]$extra"
 197         } elseif {$cmd == "continue"} {
 198             gdb_test "continue" $continue_re
 199         } else {
 200             perror "unhandled command: $cmd"
 201         }
 202     }
 203
 204     # When connected in "target remote" mode, the server should exit
 205     # when there are no processes left to debug.
 206     if { $is_remote && [info exists server_spawn_id]} {
 207         test_server_exit
 208     }
 209 }
 210
 211 # Test detaching from a process that dies just while GDB is detaching.
 212
 213 proc test_detach {multi_process cmd} {
 214     with_test_prefix "detach" {
 215         global binfile
 216
 217         clean_restart ${binfile}
 218
 219         if ![runto_main] {
 220             return -1
 221         }
 222
 223         if {$multi_process} {
 224             gdb_test_no_output "set detach-on-fork off"
 225             gdb_test_no_output "set follow-fork-mode child"
 226         }
 227
 228         # Run to _exit in the child.
 229         continue_to_exit_bp
 230
 231         do_detach $multi_process $cmd "normal"
 232     }
 233 }
 234
 235 # Same as test_detach, except set a watchpoint before detaching.
 236
 237 proc test_detach_watch {wp multi_process cmd} {
 238     if { $wp == "hw" && [skip_hw_watchpoint_tests] } {
 239         unsupported "hw watchpoint"
 240         return
 241     }
 242     with_test_prefix "watchpoint:$wp" {
 243         global binfile decimal
 244
 245         clean_restart ${binfile}
 246
 247         if ![runto_main] {
 248             return -1
 249         }
 250
 251         if {$multi_process} {
 252             gdb_test_no_output "set detach-on-fork off"
 253             gdb_test_no_output "set follow-fork-mode child"
 254
 255             gdb_breakpoint "child_function" temporary
 256             gdb_continue_to_breakpoint "child_function" ".*"
 257         }
 258
 259         if { $wp == "hw" } {
 260             # Set a watchpoint in the child.
 261             gdb_test "watch globalvar" ".* watchpoint $decimal: globalvar"
 262
 263             # Continue to the _exit breakpoint.  This arms the watchpoint
 264             # registers in all threads.  Detaching will thus need to clear
 265             # them out, and handle the case of the thread disappearing
 266             # while doing that (on targets that need to detach from each
 267             # thread individually).
 268             continue_to_exit_bp
 269         } else {
 270             # Force software watchpoints.
 271             gdb_test_no_output "set can-use-hw-watchpoints 0"
 272
 273             # As above, but flip order, other wise things take too long.
 274             continue_to_exit_bp
 275             gdb_test "watch globalvar" "Watchpoint $decimal: globalvar"
 276
 277             if { $multi_process == 0 && $cmd == "continue" } {
 278                 setup_kfail "gdb/28375" "*-*-*"
 279             }
 280         }
 281
 282         do_detach $multi_process $cmd "normal"
 283     }
 284 }
 285
 286 # Test detaching from a process that dies _before_ GDB starts
 287 # detaching.
 288
 289 proc test_detach_killed_outside {multi_process cmd} {
 290     with_test_prefix "killed outside" {
 291         global binfile
 292
 293         clean_restart ${binfile}
 294
 295         if ![runto_main] {
 296             return -1
 297         }
 298
 299         gdb_test_no_output "set breakpoint always-inserted on"
 300
 301         if {$multi_process} {
 302             gdb_test_no_output "set detach-on-fork off"
 303             gdb_test_no_output "set follow-fork-mode child"
 304         }
 305
 306         # Run to _exit in the child.
 307         continue_to_exit_bp
 308
 309         set childpid [get_integer_valueof "mypid" -1]
 310         if { $childpid == -1 } {
 311             untested "failed to extract child pid"
 312             return -1
 313         }
 314
 315         remote_exec target "kill -9 ${childpid}"
 316
 317         # Give it some time to die.
 318         sleep 2
 319
 320         do_detach $multi_process $cmd "signal"
 321     }
 322 }
 323
 324 # The test proper.  MULTI_PROCESS is true if testing the multi-process
 325 # variant.
 326
 327 proc do_test {multi_process cmd} {
 328     global testfile srcfile binfile
 329
 330     if {$multi_process && $cmd == "detach"
 331         && [target_info exists gdb,noinferiorio]} {
 332         # This requires inferior I/O to tell whether both the parent
 333         # and child exit successfully.
 334         return
 335     }
 336
 337     set binfile [standard_output_file ${testfile}-$multi_process-$cmd]
 338     set options {debug pthreads}
 339     if {$multi_process} {
 340         lappend options "additional_flags=-DMULTIPROCESS"
 341     }
 342
 343     if {[build_executable "failed to build" \
 344              $testfile-$multi_process-$cmd $srcfile $options] == -1} {
 345         return -1
 346     }
 347
 348     test_detach $multi_process $cmd
 349     foreach wp {"sw" "hw"} {
 350         test_detach_watch $wp $multi_process $cmd
 351     }
 352     test_detach_killed_outside $multi_process $cmd
 353 }
 354
 355 foreach multi_process {0 1} {
 356     set mode [expr {$multi_process ? "multi-process" : "single-process"}]
 357     foreach cmd {"detach" "continue"} {
 358         with_test_prefix "$mode: $cmd" {
 359             do_test $multi_process $cmd
 360         }
 361     }
 362 }