gdb/testsuite/gdb.base/patch.exp

   1 # Copyright 2022-2023 Free Software Foundation, Inc.
   2
   3 # This program is free software; you can redistribute it and/or modify
   4 # it under the terms of the GNU General Public License as published by
   5 # the Free Software Foundation; either version 3 of the License, or
   6 # (at your option) any later version.
   7 #
   8 # This program is distributed in the hope that it will be useful,
   9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 # GNU General Public License for more details.
  12 #
  13 # You should have received a copy of the GNU General Public License
  14 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15
  16 # Test patching executables and core files, with "set write on".
  17
  18 standard_testfile
  19
  20 if {[build_executable "failed to prepare" $testfile $srcfile debug]} {
  21     return -1
  22 }
  23
  24 # Check that we can patch an executable.
  25
  26 with_test_prefix "exec" {
  27     clean_restart
  28
  29     gdb_test_no_output "set write on"
  30
  31     gdb_load $binfile
  32
  33     gdb_test "p extern_global" " = 1" "read original value"
  34     gdb_test "p extern_global = 2" " = 2" "modify value"
  35     gdb_test "p extern_global" " = 2" "value modified"
  36
  37     clean_restart $binfile
  38
  39     gdb_test "p extern_global" " = 2" "value modified persisted"
  40 }
  41
  42 # Check that we can patch a core file.
  43
  44 # Generate a core file.
  45 with_test_prefix "gcore" {
  46     clean_restart $binfile
  47
  48     if {![runto_main]} {
  49         return
  50     }
  51
  52     # Extract the value at PC, and add 1, letting it wrap if
  53     # necessary.  This is the value we will poke into memory.
  54     set poke_value ""
  55     gdb_test_multiple "p/x (*(unsigned char *) \$pc) + 1" "compute poke value" {
  56         -re -wrap " = ($hex)" {
  57             set poke_value $expect_out(1,string)
  58             pass $gdb_test_name
  59         }
  60     }
  61     if {$poke_value == ""} {
  62         return
  63     }
  64
  65     set corefile [standard_output_file gcore.test]
  66     set core_supported [gdb_gcore_cmd "$corefile" "save a corefile"]
  67     if {!$core_supported} {
  68         return
  69     }
  70 }
  71
  72 # Load it into GDB with "set write on", and change the instruction at
  73 # PC.
  74 with_test_prefix "load core, write on" {
  75     # Don't load a binary, we want to make sure we're patching the
  76     # core, not the executable.
  77     clean_restart
  78
  79     gdb_test_no_output "set write on"
  80
  81     set core_loaded [gdb_core_cmd "$corefile" "re-load generated corefile"]
  82     if { $core_loaded == -1 } {
  83         return
  84     }
  85
  86     gdb_test "p/x *(unsigned char *) \$pc = $poke_value" \
  87         " = $poke_value" \
  88         "poke value"
  89     gdb_test "p/x *(unsigned char *) \$pc" \
  90         " = $poke_value" \
  91         "value modified"
  92 }
  93
  94 # Re-load it into a new GDB session, now with "set write off", and
  95 # confirm the value change persisted.
  96 with_test_prefix "re-load modified core" {
  97     # Don't load a binary, we want to make sure we've patched the
  98     # core, not the executable.
  99     clean_restart
 100
 101     set core_loaded [gdb_core_cmd "$corefile" "re-load generated corefile"]
 102     gdb_assert { $core_loaded != -1 } "core re-loaded"
 103
 104     gdb_test "p/x *(unsigned char *) \$pc" \
 105         " = $poke_value" \
 106         "value modified persisted"
 107 }