gdb/testsuite/gdb.threads/step-over-exec.exp

# Copyright 2020-2021 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/>.

# Test stepping over an exec syscall instruction in a multi-threaded program.

standard_testfile .c -execd.c

set syscalls_src $srcdir/lib/my-syscalls.S

# EXECR_THREAD is "leader" or "other", and decides which thread does the exec.
#
# If DIFFERENT_TEXT_SEGMENTS is true, the exec'er and exec'd program are
# compiled with different, explicit text segment addresses.  This makes it so
# the address of the displaced stepping buffer in the old executable is likely
# not accessible in the new executable.  This might catch cases where GDB tries
# (wrongfully) to restore the bytes saved from the old executable in the new
# executable.
#
# DISPLACED_STEPPING is "auto" or "off" and controls the value of "set
# displaced-stepping".

proc do_test { execr_thread different_text_segments displaced_stepping } {
    global srcdir subdir srcfile srcfile2 binfile
    global syscalls_src
    global decimal hex

    set execr_srcs [list $srcdir/$subdir/$srcfile $syscalls_src]
    set execd_srcs [list $srcdir/$subdir/$srcfile2]

    # Generate unique filenames for each case.
    set execr_binfile $binfile-execr-thread-$execr_thread-diff-text-segs-$different_text_segments
    set execd_binfile $execr_binfile-execd

    set execr_opts [list debug]
    set execd_opts [list debug]

    if { $different_text_segments } {
	lappend execr_opts "ldflags=-Wl,-Ttext-segment=0x600000"
	lappend execd_opts "ldflags=-Wl,-Ttext-segment=0x800000"
    }

    if { $execr_thread == "leader" } {
	lappend execr_opts "additional_flags=-DLEADER_DOES_EXEC"
    } elseif { $execr_thread == "other" } {
	lappend execr_opts "additional_flags=-DOTHER_DOES_EXEC"
    } else {
	error "Invalid execr_thread value: $execr_thread."
    }

    # Compile execr binary (the one that does the exec).
    if {[gdb_compile_pthreads $execr_srcs $execr_binfile executable $execr_opts] != "" } {
	return -1
    }

    # Compile the second binary (the one that gets exec'd).
    if {[gdb_compile $execd_srcs $execd_binfile executable $execd_opts] != "" } {
	return -1
    }

    clean_restart ${execr_binfile}

    gdb_test_no_output "set displaced-stepping $displaced_stepping"

    if ![runto_main] {
	return
    }

    # Leave breakpoint main inserted, we expect to hit it after exec.

    # This breakpoint will be stepped by whatever thread does the exec.
    gdb_test "break my_execve_syscall if 0" "Breakpoint $decimal at $hex.*"

    # Continue across exec to main.
    if { [target_is_gdbserver] } {
	setup_kfail gdb/27020 "*-*-*"
    }
    set failed [gdb_test "continue" \
		    "process $decimal is executing new program: .* hit Breakpoint $decimal, main .*" \
		    "continue across exec"]
    if { $failed } {
	return
    }

    # Just to confirm we are indeed in the execd program.
    gdb_test "print a_variable_in_execd" " = 1212"

    # Continue execution to make sure we can step over the breakpoint on main.
    # It would be nice to use gdb_continue_to_end to ensure the program can
    # exit properly, but it hangs due to PR gdb/26995.
    gdb_breakpoint foo
    gdb_test "continue" "Breakpoint $decimal, foo .*" \
	"continue to foo"
}

foreach_with_prefix displaced_stepping {auto off} {
    foreach_with_prefix different_text_segments {true false} {
	foreach_with_prefix execr_thread {leader other} {
	    do_test $execr_thread $different_text_segments $displaced_stepping
	}
    }
}