gdb/testsuite/gdb.base/attach-wait-input.exp

# Copyright 2014-2020 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/>.  */

# Verify that GDB waits for the "attach" command to finish before
# processing the following command.
#
# GDB used to have a race where on async targets, in the small window
# between the attach request and the initial stop for the attach, GDB
# was still processing user input.
#
# The issue was originally detected with:
#
#  echo -e "attach PID\nset xxx=1" | gdb
#
# In that scenario, stdin is not a tty, which disables readline.
# Explicitly turning off editing exercises the same code path, and is
# simpler to do, so we test with both editing on and off.

# The test uses the "attach" command.
if [use_gdb_stub] {
    return
}

standard_testfile

if {[build_executable "failed to build" $testfile $srcfile debug]} {
    return -1
}

# Start the program running, and return its PID, ready for attaching.

proc start_program {binfile} {
    global gdb_prompt
    global decimal

    clean_restart $binfile

    if ![runto setup_done] then {
	fail "can't run to setup_done"
	return 0
    }

    # Get the PID of the test process.
    set testpid ""
    set test "get inferior process ID"
    gdb_test_multiple "p mypid" $test {
	-re " = ($decimal)\r\n$gdb_prompt $" {
	    set testpid $expect_out(1,string)
	    pass $test
	}
    }

    gdb_test "detach" "Detaching from program: .*"

    if {$testpid == ""} {
	return
    }

    return $testpid
}

# Do test proper.  EDITING indicates whether "set editing" is on or
# off.

proc test { editing } {
    global gdb_prompt
    global binfile
    global decimal

    with_test_prefix "editing $editing" {

	set testpid [start_program $binfile]
	if {$testpid == ""} {
	    return
	}

	# Enable/disable readline.
	gdb_test_no_output "set editing $editing"

	# Send both commands at once.
	send_gdb "attach $testpid\nprint should_exit = 1\n"

	# Use gdb_expect directly instead of gdb_test_multiple to
	# avoid races with the double prompt.
	set test "attach and print"
	gdb_expect {
	    -re "Attaching to program.*process $testpid\r\n.*$gdb_prompt.*$decimal = 1\r\n$gdb_prompt $" {
		pass "$test"
	    }
	    timeout {
		fail "$test (timeout)"
	    }
	}

	# As we've used attach, on quit, we'll detach from the
	# program.  Explicitly kill it in case we failed above.
	gdb_test "kill" \
	    "" \
	    "after attach, exit" \
	    "Kill the program being debugged.*y or n. $" \
	    "y"
    }
}

foreach editing {"on" "off"} {
    test $editing
}