http://sourceware.org/ml/gdb-patches/2015-10/msg00301.html
Subject: [PATCH 1/3] Never kill PID on: gdb exec PID
Hi,
in some cases with deleted main executable GDB will want to kill the inferior.
$ cp /bin/sleep /tmp/sleep;/tmp/sleep 1h&p=$!
$ rm /tmp/sleep
$ gdb /tmp/sleep $p
GNU gdb (GDB) 7.10.50.20151016-cvs
/tmp/sleep: No such file or directory.
Attaching to process 9694
/tmp/sleep (deleted): No such file or directory.
A program is being debugged already. Kill it? (y or n) _
The first attachment of "/tmp/sleep" commandline argument errors at:
#0 throw_error (error=GENERIC_ERROR, fmt=0x116d135 "%s.") at ./common/common-exceptions.c:371
#1 in throw_perror_with_name (errcode=GENERIC_ERROR, string=0x7fffffffdb96 "/dfsfds") at utils.c:974
#2 in perror_with_name (string=0x7fffffffdb96 "/dfsfds") at utils.c:982
#3 in exec_file_attach (filename=0x7fffffffdb96 "/dfsfds", from_tty=1) at exec.c:268
267 if (scratch_chan < 0)
268 perror_with_name (filename);
#4 in catch_command_errors_const (command=0x80f59f <exec_file_attach>, arg=0x7fffffffdb96 "/dfsfds", from_tty=1) at main.c:395
#5 in captured_main (data=0x7fffffffd6f0) at main.c:1051
1051 if (catch_command_errors_const (exec_file_attach, execarg,
1052 !batch_flag))
Then GDB tries to attach to the process $p:
#0 inferior_appeared (inf=0x240e0b0, pid=29210) at inferior.c:305
#1 in inf_ptrace_attach (ops=0x2339540, args=0x21dcdc0 "29210", from_tty=1) at inf-ptrace.c:206
#2 in linux_nat_attach (ops=0x2339540, args=0x21dcdc0 "29210", from_tty=1) at linux-nat.c:1278
#3 in attach_command (args=0x21dcdc0 "29210", from_tty=1) at infcmd.c:2748
#4 in catch_command_errors (command=0x79d7e5 <attach_command>, arg=0x7fffffffdb9e "29210", from_tty=1) at main.c:368
#5 in captured_main (data=0x7fffffffd6f0) at main.c:1082
1082 if (catch_command_errors (attach_command, pid_or_core_arg,
1083 !batch_flag) == 0)
This succeeds and since this moment GDB has a valid inferior. But despite that
the lines
1082 if (catch_command_errors (attach_command, pid_or_core_arg,
1083 !batch_flag) == 0)
still fail because consequently attach_command() fails to find the associated
executable file:
#0 throw_error (error=GENERIC_ERROR, fmt=0x116d135 "%s.") at ./common/common-exceptions.c:371
#1 in throw_perror_with_name (errcode=GENERIC_ERROR, string=0x2477860 "/tmp/sleep (deleted)") at utils.c:974
#2 in perror_with_name (string=0x2477860 "/tmp/sleep (deleted)") at utils.c:982
#3 in exec_file_attach (filename=0x2477860 "/tmp/sleep (deleted)", from_tty=1) at exec.c:268
267 if (scratch_chan < 0)
268 perror_with_name (filename);
#4 in exec_file_locate_attach (pid=29210, from_tty=1) at exec.c:173
#5 in attach_command_post_wait (args=0x24739b0 "29210", from_tty=1, async_exec=0) at infcmd.c:2628
#6 in attach_command_continuation (args=0x2473590, err=0) at infcmd.c:2700
#7 in do_my_continuations_1 (pmy_chain=0x7fffffffd190, err=0) at continuations.c:59
#8 in do_my_continuations (list=0x240e130, err=0) at continuations.c:83
#9 in do_all_inferior_continuations (err=0) at continuations.c:125
#10 in inferior_event_handler (event_type=INF_EXEC_COMPLETE, client_data=0x0) at inf-loop.c:60
#11 in fetch_inferior_event (client_data=0x0) at infrun.c:3929
#12 in inferior_event_handler (event_type=INF_REG_EVENT, client_data=0x0) at inf-loop.c:44
#13 in handle_target_event (error=0, client_data=0x0) at linux-nat.c:4681
#14 in handle_file_event (file_ptr=0x21e4170, ready_mask=1) at event-loop.c:708
#15 in gdb_wait_for_event (block=0) at event-loop.c:834
#16 in gdb_do_one_event () at event-loop.c:298
#17 in wait_sync_command_done () at top.c:373
#18 in maybe_wait_sync_command_done (was_sync=0) at top.c:388
#19 in catch_command_errors (command=0x79d7e5 <attach_command>, arg=0x7fffffffdb9e "29210", from_tty=1) at main.c:370
#20 in captured_main (data=0x7fffffffd6f0) at main.c:1082
1082 if (catch_command_errors (attach_command, pid_or_core_arg,
1083 !batch_flag) == 0)
and therefore GDB executes the following:
(gdb) bt
#5 in query (ctlstr=0x1141ae8 "A program is being debugged already. Kill it? ") at utils.c:1371
#6 in target_preopen (from_tty=1) at target.c:2183
2179 if (have_inferiors ())
2180 {
2181 if (!from_tty
2182 || !have_live_inferiors ()
2183 || query (_("A program is being debugged already. Kill it? ")))
2184 iterate_over_inferiors (dispose_inferior, NULL);
2185 else
2186 error (_("Program not killed."));
2187 }
#7 in core_open (arg=0x7fffffffdb9f "9694", from_tty=1) at corelow.c:283
#8 in core_file_command (filename=0x7fffffffdb9f "9694", from_tty=1) at corefile.c:77
#9 in catch_command_errors (command=0x86ca16 <core_file_command>, arg=0x7fffffffdb9f "9694", from_tty=1) at main.c:368
#10 in captured_main (data=0x7fffffffd6f0) at main.c:1084
1084 catch_command_errors (core_file_command, pid_or_core_arg,
1085 !batch_flag);
No regressions on {x86_64,x86_64-m32,i686}-fedora24pre-linux-gnu.
Thanks,
Jan
gdb/ChangeLog
2015-10-16 Jan Kratochvil <jan.kratochvil@redhat.com>
* main.c (captured_main): Run core_file_command for pid_or_core_arg
only if not have_inferiors ().
gdb/testsuite/ChangeLog
2015-10-16 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.base/attach-kills.c: New.
* gdb.base/attach-kills.exp: New.
---
gdb/testsuite/gdb.base/attach-kills.c | 25 ++++++++++++++++
gdb/testsuite/gdb.base/attach-kills.exp | 49 +++++++++++++++++++++++++++++++
2 files changed, 74 insertions(+)
create mode 100644 gdb/testsuite/gdb.base/attach-kills.c
create mode 100644 gdb/testsuite/gdb.base/attach-kills.exp
Index: gdb-7.2/gdb/main.c
===================================================================
--- gdb-7.2.orig/gdb/main.c 2015-10-16 22:53:14.000000000 +0200
+++ gdb-7.2/gdb/main.c 2015-10-16 22:53:58.840722140 +0200
@@ -975,7 +975,10 @@ Can't attach to process and specify a co
if (isdigit (pid_or_core_arg[0]))
{
if (catch_command_errors (attach_command, pid_or_core_arg,
- !batch_flag, RETURN_MASK_ALL) == 0)
+ !batch_flag, RETURN_MASK_ALL) == 0
+ /* attach_command could succeed partially and core_file_command
+ would try to kill it. */
+ && !have_inferiors ())
catch_command_errors (core_file_command, pid_or_core_arg,
!batch_flag, RETURN_MASK_ALL);
}
Index: gdb-7.2/gdb/testsuite/gdb.base/attach-kills.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ gdb-7.2/gdb/testsuite/gdb.base/attach-kills.c 2015-10-16 22:53:22.843486331 +0200
@@ -0,0 +1,25 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2015 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <unistd.h>
+
+int
+main (void)
+{
+ sleep (600);
+ return 0;
+}
Index: gdb-7.2/gdb/testsuite/gdb.base/attach-kills.exp
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ gdb-7.2/gdb/testsuite/gdb.base/attach-kills.exp 2015-10-16 23:02:33.791095444 +0200
@@ -0,0 +1,39 @@
+# Copyright (C) 2015 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+set testfile attach-kills
+set binfile ${objdir}/${subdir}/${testfile}
+
+if { [build_executable ${testfile}.exp $testfile] == -1 } {
+ return -1
+}
+
+# Start the program running and then wait for a bit, to be sure
+# that it can be attached to.
+
+set testpid [eval exec $binfile &]
+exec sleep 2
+
+remote_exec target "cp -pf -- $binfile $binfile-copy"
+remote_exec target "rm -f -- $binfile"
+
+set GDBFLAGS_orig $GDBFLAGS
+set GDBFLAGS "$GDBFLAGS /DoEsNoTeXySt $testpid"
+gdb_start
+set GDBFLAGS $GDBFLAGS_orig
+
+gdb_test "info inferiors" " process \[0-9\].*"
+
+remote_exec build "kill -9 ${testpid}"