gdb/linux-tdep.c

   1 /* Target-dependent code for GNU/Linux, architecture independent.
   2
   3    Copyright (C) 2009 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "gdbcore.h"
  22 #include "gdbtypes.h"
  23 #include "linux-tdep.h"
  24 #include "observer.h"
  25 #include "auxv.h"
  26 #include "target.h"
  27 #include "elf-bfd.h"
  28 #include "elf/common.h"
  29
  30 /* This function is suitable for architectures that don't
  31    extend/override the standard siginfo structure.  */
  32
  33 struct type *
  34 linux_get_siginfo_type (struct gdbarch *gdbarch)
  35 {
  36   struct type *int_type, *uint_type, *long_type, *void_ptr_type;
  37   struct type *uid_type, *pid_type;
  38   struct type *sigval_type, *clock_type;
  39   struct type *siginfo_type, *sifields_type;
  40   struct type *type;
  41
  42   int_type = arch_integer_type (gdbarch, gdbarch_int_bit (gdbarch),
  43                                 0, "int");
  44   uint_type = arch_integer_type (gdbarch, gdbarch_int_bit (gdbarch),
  45                                  1, "unsigned int");
  46   long_type = arch_integer_type (gdbarch, gdbarch_long_bit (gdbarch),
  47                                  0, "long");
  48   void_ptr_type = lookup_pointer_type (builtin_type (gdbarch)->builtin_void);
  49
  50   /* sival_t */
  51   sigval_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_UNION);
  52   TYPE_NAME (sigval_type) = xstrdup ("sigval_t");
  53   append_composite_type_field (sigval_type, "sival_int", int_type);
  54   append_composite_type_field (sigval_type, "sival_ptr", void_ptr_type);
  55
  56   /* __pid_t */
  57   pid_type = arch_type (gdbarch, TYPE_CODE_TYPEDEF, TYPE_LENGTH (int_type),
  58                         xstrdup ("__pid_t"));
  59   TYPE_TARGET_TYPE (pid_type) = int_type;
  60   TYPE_TARGET_STUB (pid_type) = 1;
  61
  62   /* __uid_t */
  63   uid_type = arch_type (gdbarch, TYPE_CODE_TYPEDEF, TYPE_LENGTH (uint_type),
  64                         xstrdup ("__uid_t"));
  65   TYPE_TARGET_TYPE (uid_type) = uint_type;
  66   TYPE_TARGET_STUB (uid_type) = 1;
  67
  68   /* __clock_t */
  69   clock_type = arch_type (gdbarch, TYPE_CODE_TYPEDEF, TYPE_LENGTH (long_type),
  70                           xstrdup ("__clock_t"));
  71   TYPE_TARGET_TYPE (clock_type) = long_type;
  72   TYPE_TARGET_STUB (clock_type) = 1;
  73
  74   /* _sifields */
  75   sifields_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_UNION);
  76
  77   {
  78     const int si_max_size = 128;
  79     int si_pad_size;
  80     int size_of_int = gdbarch_int_bit (gdbarch) / HOST_CHAR_BIT;
  81
  82     /* _pad */
  83     if (gdbarch_ptr_bit (gdbarch) == 64)
  84       si_pad_size = (si_max_size / size_of_int) - 4;
  85     else
  86       si_pad_size = (si_max_size / size_of_int) - 3;
  87     append_composite_type_field (sifields_type, "_pad",
  88                                  init_vector_type (int_type, si_pad_size));
  89   }
  90
  91   /* _kill */
  92   type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
  93   append_composite_type_field (type, "si_pid", pid_type);
  94   append_composite_type_field (type, "si_uid", uid_type);
  95   append_composite_type_field (sifields_type, "_kill", type);
  96
  97   /* _timer */
  98   type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
  99   append_composite_type_field (type, "si_tid", int_type);
 100   append_composite_type_field (type, "si_overrun", int_type);
 101   append_composite_type_field (type, "si_sigval", sigval_type);
 102   append_composite_type_field (sifields_type, "_timer", type);
 103
 104   /* _rt */
 105   type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
 106   append_composite_type_field (type, "si_pid", pid_type);
 107   append_composite_type_field (type, "si_uid", uid_type);
 108   append_composite_type_field (type, "si_sigval", sigval_type);
 109   append_composite_type_field (sifields_type, "_rt", type);
 110
 111   /* _sigchld */
 112   type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
 113   append_composite_type_field (type, "si_pid", pid_type);
 114   append_composite_type_field (type, "si_uid", uid_type);
 115   append_composite_type_field (type, "si_status", int_type);
 116   append_composite_type_field (type, "si_utime", clock_type);
 117   append_composite_type_field (type, "si_stime", clock_type);
 118   append_composite_type_field (sifields_type, "_sigchld", type);
 119
 120   /* _sigfault */
 121   type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
 122   append_composite_type_field (type, "si_addr", void_ptr_type);
 123   append_composite_type_field (sifields_type, "_sigfault", type);
 124
 125   /* _sigpoll */
 126   type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
 127   append_composite_type_field (type, "si_band", long_type);
 128   append_composite_type_field (type, "si_fd", int_type);
 129   append_composite_type_field (sifields_type, "_sigpoll", type);
 130
 131   /* struct siginfo */
 132   siginfo_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
 133   TYPE_NAME (siginfo_type) = xstrdup ("siginfo");
 134   append_composite_type_field (siginfo_type, "si_signo", int_type);
 135   append_composite_type_field (siginfo_type, "si_errno", int_type);
 136   append_composite_type_field (siginfo_type, "si_code", int_type);
 137   append_composite_type_field_aligned (siginfo_type,
 138                                        "_sifields", sifields_type,
 139                                        TYPE_LENGTH (long_type));
 140
 141   return siginfo_type;
 142 }
 143
 144 int
 145 linux_has_shared_address_space (void)
 146 {
 147   /* Determine whether we are running on uClinux or normal Linux
 148      kernel.  */
 149   CORE_ADDR dummy;
 150   int target_is_uclinux;
 151
 152   target_is_uclinux
 153     = (target_auxv_search (&current_target, AT_NULL, &dummy) > 0
 154        && target_auxv_search (&current_target, AT_PAGESZ, &dummy) == 0);
 155
 156   return target_is_uclinux;
 157 }
 158
 159 /* Observer for the executable_changed event, to check whether the new
 160    exec binary is a PIE (Position Independent Executable) specimen, which
 161    is currently unsupported.  */
 162
 163 static void
 164 check_is_pie_binary (void)
 165 {
 166   Elf_Internal_Ehdr *elf_hdr;
 167
 168   if (!exec_bfd)
 169     return;
 170   else if (bfd_get_flavour (exec_bfd) != bfd_target_elf_flavour)
 171     return;
 172
 173   if (elf_tdata (exec_bfd)->elf_header->e_type == ET_DYN)
 174     warning (_("\
 175 The current binary is a PIE (Position Independent Executable), which\n\
 176 GDB does NOT currently support.  Most debugger features will fail if used\n\
 177 in this session.\n"));
 178 }
 179
 180 /* Provide a prototype to silence -Wmissing-prototypes.  */
 181 extern initialize_file_ftype _initialize_linux_tdep;
 182
 183 void
 184 _initialize_linux_tdep (void)
 185 {
 186   observer_attach_executable_changed (check_is_pie_binary);
 187 }