gdb/gcore-elf.c

   1 /* Copyright (C) 2021-2022 Free Software Foundation, Inc.
   2
   3    This file is part of GDB.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include "defs.h"
  19 #include "gcore-elf.h"
  20 #include "elf-bfd.h"
  21 #include "target.h"
  22 #include "regcache.h"
  23 #include "gdbarch.h"
  24 #include "gdbthread.h"
  25 #include "inferior.h"
  26 #include "regset.h"
  27 #include "gdbsupport/tdesc.h"
  28
  29 /* Structure for passing information from GCORE_COLLECT_THREAD_REGISTERS
  30    via an iterator to GCORE_COLLECT_REGSET_SECTION_CB. */
  31
  32 struct gcore_elf_collect_regset_section_cb_data
  33 {
  34   gcore_elf_collect_regset_section_cb_data
  35         (struct gdbarch *gdbarch, const struct regcache *regcache,
  36          bfd *obfd, ptid_t ptid, gdb_signal stop_signal,
  37          gdb::unique_xmalloc_ptr<char> *note_data, int *note_size)
  38     : gdbarch (gdbarch), regcache (regcache), obfd (obfd),
  39       note_data (note_data), note_size (note_size),
  40       stop_signal (stop_signal)
  41   {
  42     /* The LWP is often not available for bare metal target, in which case
  43        use the tid instead.  */
  44     if (ptid.lwp_p ())
  45       lwp = ptid.lwp ();
  46     else
  47       lwp = ptid.tid ();
  48   }
  49
  50   struct gdbarch *gdbarch;
  51   const struct regcache *regcache;
  52   bfd *obfd;
  53   gdb::unique_xmalloc_ptr<char> *note_data;
  54   int *note_size;
  55   unsigned long lwp;
  56   enum gdb_signal stop_signal;
  57   bool abort_iteration = false;
  58 };
  59
  60 /* Callback for ITERATE_OVER_REGSET_SECTIONS that records a single
  61    regset in the core file note section.  */
  62
  63 static void
  64 gcore_elf_collect_regset_section_cb (const char *sect_name,
  65                                      int supply_size, int collect_size,
  66                                      const struct regset *regset,
  67                                      const char *human_name, void *cb_data)
  68 {
  69   struct gcore_elf_collect_regset_section_cb_data *data
  70     = (struct gcore_elf_collect_regset_section_cb_data *) cb_data;
  71   bool variable_size_section = (regset != nullptr
  72                                 && regset->flags & REGSET_VARIABLE_SIZE);
  73
  74   gdb_assert (variable_size_section || supply_size == collect_size);
  75
  76   if (data->abort_iteration)
  77     return;
  78
  79   gdb_assert (regset != nullptr && regset->collect_regset != nullptr);
  80
  81   /* This is intentionally zero-initialized by using std::vector, so
  82      that any padding bytes in the core file will show as 0.  */
  83   std::vector<gdb_byte> buf (collect_size);
  84
  85   regset->collect_regset (regset, data->regcache, -1, buf.data (),
  86                           collect_size);
  87
  88   /* PRSTATUS still needs to be treated specially.  */
  89   if (strcmp (sect_name, ".reg") == 0)
  90     data->note_data->reset (elfcore_write_prstatus
  91                             (data->obfd, data->note_data->release (),
  92                              data->note_size, data->lwp,
  93                              gdb_signal_to_host (data->stop_signal),
  94                              buf.data ()));
  95   else
  96     data->note_data->reset (elfcore_write_register_note
  97                             (data->obfd, data->note_data->release (),
  98                              data->note_size, sect_name, buf.data (),
  99                              collect_size));
 100
 101   if (*data->note_data == nullptr)
 102     data->abort_iteration = true;
 103 }
 104
 105 /* Records the register state of thread PTID out of REGCACHE into the note
 106    buffer represented by *NOTE_DATA and NOTE_SIZE.  OBFD is the bfd into
 107    which the core file is being created, and STOP_SIGNAL is the signal that
 108    cause thread PTID to stop.  */
 109
 110 static void
 111 gcore_elf_collect_thread_registers
 112         (const struct regcache *regcache, ptid_t ptid, bfd *obfd,
 113          gdb::unique_xmalloc_ptr<char> *note_data, int *note_size,
 114          enum gdb_signal stop_signal)
 115 {
 116   struct gdbarch *gdbarch = regcache->arch ();
 117   gcore_elf_collect_regset_section_cb_data data (gdbarch, regcache, obfd,
 118                                                  ptid, stop_signal,
 119                                                  note_data, note_size);
 120   gdbarch_iterate_over_regset_sections
 121     (gdbarch, gcore_elf_collect_regset_section_cb, &data, regcache);
 122 }
 123
 124 /* See gcore-elf.h.  */
 125
 126 void
 127 gcore_elf_build_thread_register_notes
 128   (struct gdbarch *gdbarch, struct thread_info *info, gdb_signal stop_signal,
 129    bfd *obfd, gdb::unique_xmalloc_ptr<char> *note_data, int *note_size)
 130 {
 131   struct regcache *regcache
 132     = get_thread_arch_regcache (info->inf->process_target (),
 133                                 info->ptid, gdbarch);
 134   target_fetch_registers (regcache, -1);
 135   gcore_elf_collect_thread_registers (regcache, info->ptid, obfd,
 136                                       note_data, note_size, stop_signal);
 137 }
 138
 139 /* See gcore-elf.h.  */
 140
 141 void
 142 gcore_elf_make_tdesc_note (bfd *obfd,
 143                            gdb::unique_xmalloc_ptr<char> *note_data,
 144                            int *note_size)
 145 {
 146   /* Append the target description to the core file.  */
 147   const struct target_desc *tdesc = gdbarch_target_desc (target_gdbarch ());
 148   const char *tdesc_xml
 149     = tdesc == nullptr ? nullptr : tdesc_get_features_xml (tdesc);
 150   if (tdesc_xml != nullptr && *tdesc_xml != '\0')
 151     {
 152       /* Skip the leading '@'.  */
 153       if (*tdesc_xml == '@')
 154         ++tdesc_xml;
 155
 156       /* Include the null terminator in the length.  */
 157       size_t tdesc_len = strlen (tdesc_xml) + 1;
 158
 159       /* Now add the target description into the core file.  */
 160       note_data->reset (elfcore_write_register_note (obfd,
 161                                                      note_data->release (),
 162                                                      note_size,
 163                                                      ".gdb-tdesc", tdesc_xml,
 164                                                      tdesc_len));
 165     }
 166 }