From 584cf46d0ab5960cca76bfaf414cee5641166868 Mon Sep 17 00:00:00 2001 From: Hannes Domani Date: Wed, 12 Feb 2020 17:53:32 +0100 Subject: [PATCH] Rebase executable to match relocated base address Windows executables linked with -dynamicbase get a new base address when loaded, which makes debugging impossible if the executable isn't also rebased in gdb. The new base address is read from the Process Environment Block. gdb/ChangeLog: 2020-03-03 Hannes Domani * windows-tdep.c (windows_solib_create_inferior_hook): New function. (windows_init_abi): Set and use windows_so_ops. --- gdb/ChangeLog | 5 +++++ gdb/windows-tdep.c | 55 +++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 59 insertions(+), 1 deletion(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 291e83af8e7..2a1f3be79af 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2020-03-03 Hannes Domani + + * windows-tdep.c (windows_solib_create_inferior_hook): New function. + (windows_init_abi): Set and use windows_so_ops. + 2020-03-03 Sergio Durigan Junior * printcmd.c (print_c_string): Check also for TYPE_CODE_PTR diff --git a/gdb/windows-tdep.c b/gdb/windows-tdep.c index 6eef3fbd969..4e5d8303ca4 100644 --- a/gdb/windows-tdep.c +++ b/gdb/windows-tdep.c @@ -34,6 +34,9 @@ #include "solib.h" #include "solib-target.h" #include "gdbcore.h" +#include "coff/internal.h" +#include "libcoff.h" +#include "solist.h" /* Windows signal numbers differ between MinGW flavors and between those and Cygwin. The below enumeration was gleaned from the @@ -812,6 +815,53 @@ windows_get_siginfo_type (struct gdbarch *gdbarch) return siginfo_type; } +/* Implement the "solib_create_inferior_hook" target_so_ops method. */ + +static void +windows_solib_create_inferior_hook (int from_tty) +{ + CORE_ADDR exec_base = 0; + + /* Find base address of main executable in + TIB->process_environment_block->image_base_address. */ + struct gdbarch *gdbarch = target_gdbarch (); + enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); + int ptr_bytes; + int peb_offset; /* Offset of process_environment_block in TIB. */ + int base_offset; /* Offset of image_base_address in PEB. */ + if (gdbarch_ptr_bit (gdbarch) == 32) + { + ptr_bytes = 4; + peb_offset = 48; + base_offset = 8; + } + else + { + ptr_bytes = 8; + peb_offset = 96; + base_offset = 16; + } + CORE_ADDR tlb; + gdb_byte buf[8]; + if (target_get_tib_address (inferior_ptid, &tlb) + && !target_read_memory (tlb + peb_offset, buf, ptr_bytes)) + { + CORE_ADDR peb = extract_unsigned_integer (buf, ptr_bytes, byte_order); + if (!target_read_memory (peb + base_offset, buf, ptr_bytes)) + exec_base = extract_unsigned_integer (buf, ptr_bytes, byte_order); + } + + /* Rebase executable if the base address changed because of ASLR. */ + if (symfile_objfile != nullptr && exec_base != 0) + { + CORE_ADDR vmaddr = pe_data (exec_bfd)->pe_opthdr.ImageBase; + if (vmaddr != exec_base) + objfile_rebase (symfile_objfile, exec_base - vmaddr); + } +} + +static struct target_so_ops windows_so_ops; + /* To be called from the various GDB_OSABI_CYGWIN handlers for the various Windows architectures and machine types. */ @@ -830,7 +880,10 @@ windows_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) set_gdbarch_gdb_signal_to_target (gdbarch, windows_gdb_signal_to_target); - set_solib_ops (gdbarch, &solib_target_so_ops); + windows_so_ops = solib_target_so_ops; + windows_so_ops.solib_create_inferior_hook + = windows_solib_create_inferior_hook; + set_solib_ops (gdbarch, &windows_so_ops); set_gdbarch_get_siginfo_type (gdbarch, windows_get_siginfo_type); } -- 2.30.2