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# Copyright 2022 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 patching executables and core files, with "set write on".
standard_testfile
if {[build_executable "failed to prepare" $testfile $srcfile debug]} {
return -1
}
# Check that we can patch an executable.
with_test_prefix "exec" {
clean_restart
gdb_test_no_output "set write on"
gdb_load $binfile
gdb_test "p extern_global" " = 1" "read original value"
gdb_test "p extern_global = 2" " = 2" "modify value"
gdb_test "p extern_global" " = 2" "value modified"
clean_restart $binfile
gdb_test "p extern_global" " = 2" "value modified persisted"
}
# Check that we can patch a core file.
# Generate a core file.
with_test_prefix "gcore" {
clean_restart $binfile
if {![runto_main]} {
return
}
# Extract the value at PC, and add 1, letting it wrap if
# necessary. This is the value we will poke into memory.
set poke_value ""
gdb_test_multiple "p/x (*(unsigned char *) \$pc) + 1" "compute poke value" {
-re -wrap " = ($hex)" {
set poke_value $expect_out(1,string)
pass $gdb_test_name
}
}
if {$poke_value == ""} {
return
}
set corefile [standard_output_file gcore.test]
set core_supported [gdb_gcore_cmd "$corefile" "save a corefile"]
if {!$core_supported} {
return
}
}
# Load it into GDB with "set write on", and change the instruction at
# PC.
with_test_prefix "load core, write on" {
# Don't load a binary, we want to make sure we're patching the
# core, not the executable.
clean_restart
gdb_test_no_output "set write on"
set core_loaded [gdb_core_cmd "$corefile" "re-load generated corefile"]
if { $core_loaded == -1 } {
return
}
gdb_test "p/x *(unsigned char *) \$pc = $poke_value" \
" = $poke_value" \
"poke value"
gdb_test "p/x *(unsigned char *) \$pc" \
" = $poke_value" \
"value modified"
}
# Re-load it into a new GDB session, now with "set write off", and
# confirm the value change persisted.
with_test_prefix "re-load modified core" {
# Don't load a binary, we want to make sure we've patched the
# core, not the executable.
clean_restart
set core_loaded [gdb_core_cmd "$corefile" "re-load generated corefile"]
gdb_assert { $core_loaded != -1 } "core re-loaded"
gdb_test "p/x *(unsigned char *) \$pc" \
" = $poke_value" \
"value modified persisted"
}
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