gdb/17347 - Regression: GDB stopped on run with attached process
authorPedro Alves <palves@redhat.com>
Thu, 11 Sep 2014 12:04:15 +0000 (13:04 +0100)
committerPedro Alves <palves@redhat.com>
Thu, 11 Sep 2014 12:08:21 +0000 (13:08 +0100)
commit98880d46bdb1e88db447f876a8ac1f2a4de97dae
tree75090eec406fd8e71498ad3d4d0f954c676dfb32
parent4c92ff2c35392b68ee9172af979483b32aaa3d7b
gdb/17347 - Regression: GDB stopped on run with attached process

Doing:

  gdb --pid=PID -ex run

Results in GDB getting a SIGTTIN, and thus ending stopped.  That's
usually indicative of a missing target_terminal_ours call.

E.g., from the PR:

 $ sleep 1h & p=$!; sleep 0.1; gdb -batch sleep $p -ex run
 [1] 28263
 [1]   Killed                  sleep 1h

 [2]+  Stopped                 gdb -batch sleep $p -ex run

The workaround is doing:

 gdb -ex "attach $PID" -ex "run"

instead of

 gdb [-p] $PID -ex "run"

With the former, gdb waits for the attach command to complete before
moving on to the "run" command, because the interpreter is in sync
mode at this point, within execute_command.  But for the latter,
attach_command is called directly from captured_main, and thus misses
that waiting.  IOW, "run" is running before the attach continuation
has run, before the program stops and attach completes.  The broken
terminal settings are just one symptom of that.  Any command that
queries or requires input results in the same.

The fix is to wait in catch_command_errors (which is specific to
main.c nowadays), just like we wait in execute_command.

gdb/ChangeLog:
2014-09-11  Pedro Alves  <palves@redhat.com>

PR gdb/17347
* main.c: Include "infrun.h".
(catch_command_errors, catch_command_errors_const): Wait for the
foreground command to complete.
* top.c (maybe_wait_sync_command_done): New function, factored out
from ...
(maybe_wait_sync_command_done): ... here.
* top.h (maybe_wait_sync_command_done): New declaration.

gdb/testsuite/ChangeLog:
2014-09-11  Pedro Alves  <palves@redhat.com>

PR gdb/17347
* lib/gdb.exp (gdb_spawn_with_cmdline_opts): New procedure.
* gdb.base/attach.exp (test_command_line_attach_run): New
procedure.
(top level): Call it.
gdb/ChangeLog
gdb/main.c
gdb/testsuite/ChangeLog
gdb/testsuite/gdb.base/attach.exp
gdb/testsuite/lib/gdb.exp
gdb/top.c
gdb/top.h