path: root/gdb/testsuite/gdb.base/foll-fork.exp

#   Copyright 1997-2020 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/>.

# Until "set follow-fork-mode" and "catch fork" are implemented on
# other targets...
#
if { ![istarget "*-*-linux*"] && ![istarget "*-*-openbsd*"] } then {
    continue
}

# Test relies on checking follow-fork output. Do not run if gdb debug is
# enabled as it will be redirected to the log.
if [gdb_debug_enabled] {
    untested "debug is enabled"
    return 0
}

standard_testfile

if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
    return -1
}

proc check_fork_catchpoints {} {
  global gdb_prompt

  # Verify that the system supports "catch fork".
  gdb_test "catch fork" "Catchpoint \[0-9\]* \\(fork\\)" "insert first fork catchpoint"
  set has_fork_catchpoints 0
  gdb_test_multiple "continue" "continue to first fork catchpoint" {
    -re ".*Your system does not support this type\r\nof catchpoint.*$gdb_prompt $" {
      unsupported "continue to first fork catchpoint"
    }
    -re ".*Catchpoint.*$gdb_prompt $" {
      set has_fork_catchpoints 1
      pass "continue to first fork catchpoint"
    }
  }

  if {$has_fork_catchpoints == 0} {
    unsupported "fork catchpoints"
    return -code return
  }
}

# Test follow-fork to ensure that the correct process is followed, that
# the followed process stops where it is expected to stop, that processes
# are detached (or not) as expected, and that the inferior list has the
# expected contents after following the fork.  WHO is the argument to
# the 'set follow-fork-mode' command, DETACH is the argument to the 
# 'set detach-on-fork' command, and CMD is the GDB command used to 
# execute the program past the fork.  If the value of WHO or DETACH is
# 'default', the corresponding GDB command is skipped for that test.
# The value of CMD must be either 'next 2' or 'continue'.
proc test_follow_fork { who detach cmd } {
    global gdb_prompt
    global srcfile
    global testfile

    with_test_prefix "follow $who, detach $detach, command \"$cmd\"" {

	# Start a new debugger session each time so defaults are legitimate.
	clean_restart $testfile

	if ![runto_main] {
	    untested "could not run to main"
	    return -1
	}

	# The "Detaching..." and "Attaching..." messages may be hidden by
	# default.
	gdb_test_no_output "set verbose"

	# Set follow-fork-mode if we aren't using the default.
	if {$who == "default"} {
	    set who "parent"
	} else {
	    gdb_test_no_output "set follow-fork $who"
	}

	gdb_test "show follow-fork" \
	"Debugger response to a program call of fork or vfork is \"$who\"."

	# Set detach-on-fork mode if we aren't using the default.
	if {$detach == "default"} {
	    set detach "on"
	} else {
	    gdb_test_no_output "set detach-on-fork $detach"
	}

	gdb_test "show detach-on-fork" \
		 "Whether gdb will detach.* fork is $detach."

	# Set a breakpoint after the fork if we aren't single-stepping
	# past the fork.
	if {$cmd == "continue"} {
	    set bp_after_fork [gdb_get_line_number "set breakpoint here"]
	    gdb_test "break ${srcfile}:$bp_after_fork" \
		     "Breakpoint.*, line $bp_after_fork.*" \
		     "set breakpoint after fork"
	}

	# Set up the output we expect to see after we run.
	set expected_re ""
	if {$who == "child"} {
	    set expected_re "\\\[Attaching after.* fork to.*"
	    if {$detach == "on"} {
		append expected_re "\\\[Detaching after fork from .*"
	    }
	    append expected_re "set breakpoint here.*"
	} elseif {$who == "parent" && $detach == "on"} {
	    set expected_re "\\\[Detaching after fork from .*set breakpoint here.*"
	} else {
	    set expected_re ".*set breakpoint here.*"
	}

	# Test running past and following the fork, using the parameters
	# set above.
	gdb_test $cmd $expected_re "$cmd past fork"

	# Check that we have the inferiors arranged correctly after 
	# following the fork.
	set resume_unfollowed 0
	if {$who == "parent" && $detach == "on"} {

	    # Follow parent / detach child: the only inferior is the parent.
	    gdb_test "info inferiors" "\\* 1 .* process.*"

	} elseif {$who == "parent" && $detach == "off"} {

	    # Follow parent / keep child: two inferiors under debug, the
	    # parent is the current inferior.
	    gdb_test "info inferiors" "\\* 1 .*process.* 2 .*process.*"

	    gdb_test "inferior 2" "Switching to inferior 2 .*"
	    set resume_unfollowed 1

	} elseif {$who == "child" && $detach == "on"} {

	    # Follow child / detach parent: the child is under debug and is
	    # the current inferior.  The parent is listed but is not under
	    # debug.
	    gdb_test "info inferiors" " 1 .*<null>.*\\* 2 .*process.*"

	} elseif {$who == "child" && $detach == "off"} {

	    # Follow child / keep parent: two inferiors under debug, the
	    # child is the current inferior.
	    gdb_test "info inferiors" " 1 .*process.*\\* 2 .*process.*"

	    gdb_test "inferior 1" "Switching to inferior 1 .*"
	    set resume_unfollowed 1
	}

	if {$resume_unfollowed == 1} {
	    if {$cmd == "next 2"} {

		gdb_continue_to_end "continue unfollowed inferior to end"

	    } elseif {$cmd == "continue"} {

		gdb_continue_to_breakpoint \
		    "continue unfollowed inferior to bp" \
		    ".* set breakpoint here.*"
	    }
	}
    }
}

set reading_in_symbols_re {(?:\r\nReading in symbols for [^\r\n]*)?}

proc catch_fork_child_follow {} {
    global gdb_prompt
    global srcfile
    global reading_in_symbols_re

    set bp_after_fork [gdb_get_line_number "set breakpoint here"]

    gdb_test "catch fork" \
	"Catchpoint \[0-9\]* \\(fork\\)$reading_in_symbols_re" \
	"explicit child follow, set catch fork"

    # Verify that the catchpoint is mentioned in an "info breakpoints",
    # and further that the catchpoint mentions no process id.
    #
    set test_name "info shows catchpoint without pid"
    gdb_test_multiple "info breakpoints" "$test_name" {
	-re ".*catchpoint.*keep y.*fork\[\r\n\]+$gdb_prompt $" {
	    pass "$test_name"
	}
    }

    gdb_test "continue" \
	"Catchpoint \[0-9\]* \\(forked process \[0-9\]*\\),.*" \
	"explicit child follow, catch fork"

    # Verify that the catchpoint is mentioned in an "info breakpoints",
    # and further that the catchpoint managed to capture a process id.
    #
    set test_name "info shows catchpoint without pid"
    gdb_test_multiple "info breakpoints" "$test_name" {
	-re ".*catchpoint.*keep y.*fork, process.*$gdb_prompt $" {
	    pass "$test_name"
	}
    }

    gdb_test_no_output "set follow-fork child"

    gdb_test "tbreak ${srcfile}:$bp_after_fork" \
	"Temporary breakpoint.*, line $bp_after_fork.*" \
	"set follow-fork child, tbreak"

    set expected_re "\\\[Attaching after.* fork to.*\\\[Detaching after fork from"
    append expected_re ".* at .*$bp_after_fork.*"
    gdb_test "continue" $expected_re "set follow-fork child, hit tbreak"

    # The parent has been detached; allow time for any output it might
    # generate to arrive, so that output doesn't get confused with
    # any expected debugger output from a subsequent testpoint.
    #
    exec sleep 1

    gdb_test "delete breakpoints" \
	"" \
	"set follow-fork child, cleanup" \
	"Delete all breakpoints. \\(y or n\\) $" \
	"y"
}

proc catch_fork_unpatch_child {} {
    global gdb_prompt
    global srcfile

    set bp_exit [gdb_get_line_number "at exit"]

    gdb_test "break callee" "file .*$srcfile, line .*" \
	"unpatch child, break at callee"
    gdb_test "catch fork" "Catchpoint \[0-9\]* \\(fork\\)" \
	"unpatch child, set catch fork"

    gdb_test "continue" \
	"Catchpoint \[0-9\]* \\(forked process \[0-9\]*\\),.*" \
	"unpatch child, catch fork"

    # Delete all breakpoints and catchpoints.
    delete_breakpoints

    # Force $srcfile as the current GDB source can be in glibc sourcetree.
    gdb_test "break $srcfile:$bp_exit" \
	"Breakpoint .*file .*$srcfile, line .*" \
	"unpatch child, breakpoint at exit call"

    gdb_test_no_output "set follow-fork child" \
	"unpatch child, set follow-fork child"

    set test "unpatch child, unpatched parent breakpoints from child"
    gdb_test_multiple "continue" $test {
	-re "at exit.*$gdb_prompt $" {
	    pass "$test"
	}
	-re "SIGTRAP.*$gdb_prompt $" {
	    fail "$test"

	    # Explicitly kill this child, so we can continue gracefully
	    # with further testing...
	    send_gdb "kill\n"
	    gdb_expect {
		-re ".*Kill the program being debugged.*y or n. $" {
		    send_gdb "y\n"
		    gdb_expect -re "$gdb_prompt $" {}
		}
	    }
	}
    }
}

proc tcatch_fork_parent_follow {} {
    global gdb_prompt
    global srcfile
    global reading_in_symbols_re

    set bp_after_fork [gdb_get_line_number "set breakpoint here"]

    gdb_test "catch fork" \
	"Catchpoint \[0-9\]* \\(fork\\)$reading_in_symbols_re" \
	"explicit parent follow, set tcatch fork"

# ??rehrauer: I don't yet know how to get the id of the tcatch
# via this script, so that I can add a -do list to it.  For now,
# do the follow stuff after the catch happens.

    gdb_test "continue" \
	"Catchpoint \[0-9\]* \\(forked process \[0-9\]*\\),.*" \
	"explicit parent follow, tcatch fork"

    gdb_test_no_output "set follow-fork parent"

    gdb_test "tbreak ${srcfile}:$bp_after_fork" \
	"Temporary breakpoint.*, line $bp_after_fork.*" \
	"set follow-fork parent, tbreak"

    gdb_test "continue" \
	"\\\[Detaching after fork from.* at .*$bp_after_fork.*" \
	"set follow-fork parent, hit tbreak"

    # The child has been detached; allow time for any output it might
    # generate to arrive, so that output doesn't get confused with
    # any expected debugger output from a subsequent testpoint.
    #
    exec sleep 1

    gdb_test "delete breakpoints" \
	"" \
	"set follow-fork parent, cleanup" \
	"Delete all breakpoints. \\(y or n\\) $" \
	"y"
}

proc do_fork_tests {} {
    global gdb_prompt
    global testfile

    # Verify that help is available for "set follow-fork-mode".
    #
    gdb_test "help set follow-fork-mode" \
	"Set debugger response to a program call of fork or vfork..*
A fork or vfork creates a new process.  follow-fork-mode can be:.*
.*parent  - the original process is debugged after a fork.*
.*child   - the new process is debugged after a fork.*
The unfollowed process will continue to run..*
By default, the debugger will follow the parent process..*"

    # Verify that we can set follow-fork-mode, using an abbreviation
    # for both the flag and its value.
    #
    gdb_test_no_output "set follow-fork ch"

    gdb_test "show follow-fork" \
	"Debugger response to a program call of fork or vfork is \"child\".*" \
	"set follow-fork, using abbreviations"

    # Verify that we cannot set follow-fork-mode to nonsense.
    #
    gdb_test "set follow-fork chork" "Undefined item: \"chork\".*" \
	"set follow-fork to nonsense is prohibited"

    gdb_test_no_output "set follow-fork parent" "reset parent"

    # Check that fork catchpoints are supported, as an indicator for whether
    # fork-following is supported.
    if [runto_main] then { check_fork_catchpoints }

    # Test the basic follow-fork functionality using all combinations of
    # values for follow-fork-mode and detach-on-fork, using either a
    # breakpoint or single-step to execute past the fork.
    #
    # The first loop should be sufficient to test the defaults.  There
    # is no need to test using the defaults in other permutations (e.g.
    # "default" "on", "parent" "default", etc.).
    foreach cmd {"next 2" "continue"} {
        test_follow_fork "default" "default" $cmd
    }

    # Now test all explicit permutations.
    foreach who {"parent" "child"} {
	foreach detach {"on" "off"} {
	    foreach cmd {"next 2" "continue"} {
		test_follow_fork $who $detach $cmd
	    }
	}
    }

    # Catchpoint tests.

    # Restart to eliminate any effects of the follow-fork tests.
    clean_restart $testfile
    gdb_test_no_output "set verbose"

    # Test the ability to catch a fork, specify that the child be
    # followed, and continue.  Make the catchpoint permanent.
    #
    if [runto_main] then { catch_fork_child_follow }

    # Test that parent breakpoints are successfully detached from the
    # child at fork time, even if the user removes them from the
    # breakpoints list after stopping at a fork catchpoint.
    if [runto_main] then { catch_fork_unpatch_child }

    # Test the ability to catch a fork, specify via a -do clause that
    # the parent be followed, and continue.  Make the catchpoint temporary.
    #
    if [runto_main] then { tcatch_fork_parent_follow }
}

# This is a test of gdb's ability to follow the parent, child or both
# parent and child of a Unix fork() system call.
#
do_fork_tests

return 0