# Copyright 2017-2018 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/>.
#

# This test case verifies that GDB gracefully handles a shared library file
# vanishing after being dlopen'ed.  This consists of three nested function calls:
#
# main() -> foo() -> bar()
#
# where:
# - foo exists in solib-vanish-lib1.so, which is dlopen'ed by main()
# - bar exists in solib-vanish-lib2.so, which is dynamically linked into
#   solib-vanish-lib1.so
#
# Immediately after dlopen'ing solib-vanish-lib1.so, the so file is moved aside
# by renaming.  The main executable and solib-vanish-lib2.so are still
# accessible.
#
# If a breakpoint is set on bar(), gdb throws an error when this breakpoint is
# hit:
#
#   (gdb) r
#   Starting program: /local/gdb/git/pr_16577_repro/simple/solib-vanish-main
#
#   Breakpoint 1, BFD: reopening ./solib-vanish-lib1.so: No such file or directory
#
#   BFD: reopening ./solib-vanish-lib1.so: No such file or directory
#
#   (gdb)
#
# Notice that this does not print the current frame, i.e.:
#   bar (y=1) at solib-vanish-lib2.c:19
#   19	  return y + 1; /* break here */
#   (gdb)
#
# The current gdb git tip segfaults if we then try to step:
#   (gdb) n
#   Segmentation fault

# This test verifies that:
# 1) GDB does not segfault when stepping
# 2) The stack frame is printed

if { [skip_shlib_tests] } {
    return 0
}

# Library 2
set lib2name "solib-vanish-lib2"
set srcfile_lib2 ${srcdir}/${subdir}/${lib2name}.c
set binfile_lib2 [standard_output_file ${lib2name}.so]
set lib2_flags {debug}

# Library 1
set lib1name "solib-vanish-lib1"
set srcfile_lib1 ${srcdir}/${subdir}/${lib1name}.c
set binfile_lib1 [standard_output_file ${lib1name}.so]
set lib1_flags [list debug shlib=${binfile_lib2}]

# Main program
set testfile "solib-vanish-main"
set srcfile ${srcdir}/${subdir}/${testfile}.c
set executable ${testfile}
set binfile [standard_output_file ${executable}]
set bin_flags [list debug shlib_load additional_flags=-DVANISH_LIB=\"${binfile_lib1}\"]

if { [gdb_compile_shlib ${srcfile_lib2} ${binfile_lib2} $lib2_flags] != ""
     || [gdb_compile_shlib ${srcfile_lib1} ${binfile_lib1} $lib1_flags] != ""
     || [gdb_compile ${srcfile} ${binfile} executable $bin_flags] != "" } {
    untested "failed to compile"
    return -1
}

clean_restart $testfile

if { ![runto_main] } {
    fail "can't run to main"
    return
}

delete_breakpoints

set lib2_lineno [gdb_get_line_number "break here" ${srcfile_lib2}]

gdb_breakpoint "${lib2name}.c:${lib2_lineno}" {allow-pending}

# Verify that both the location and source code are displayed
gdb_continue_to_breakpoint "bar" \
    ".*${lib2name}.c:${lib2_lineno}.*break here.*"

# This should not segfault
gdb_test "next" \
    "" \
    "next succeeds"