gdb/corelow.c

   1 /* Core dump and executable file functions below target vector, for GDB.
   2    Copyright 1986, 1987, 1989, 1991, 1992, 1993, 1994
   3    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 2 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, write to the Free Software
  19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 #include "defs.h"
  22 #include <string.h>
  23 #include <errno.h>
  24 #include <signal.h>
  25 #include <fcntl.h>
  26 #include "frame.h"  /* required by inferior.h */
  27 #include "inferior.h"
  28 #include "symtab.h"
  29 #include "command.h"
  30 #include "bfd.h"
  31 #include "target.h"
  32 #include "gdbcore.h"
  33 #include "thread.h"
  34
  35 static void
  36 core_files_info PARAMS ((struct target_ops *));
  37
  38 #ifdef SOLIB_ADD
  39 static int
  40 solib_add_stub PARAMS ((char *));
  41 #endif
  42
  43 static void
  44 core_close PARAMS ((int));
  45
  46 static void
  47 get_core_registers PARAMS ((int));
  48
  49 /* Discard all vestiges of any previous core file
  50    and mark data and stack spaces as empty.  */
  51
  52 /* ARGSUSED */
  53 static void
  54 core_close (quitting)
  55      int quitting;
  56 {
  57   char *name;
  58   inferior_pid = 0;             /* Avoid confusion from thread stuff */
  59
  60   if (core_bfd) {
  61     name = bfd_get_filename (core_bfd);
  62     if (!bfd_close (core_bfd))
  63       warning ("cannot close \"%s\": %s",
  64                bfd_filename, bfd_errmsg (bfd_get_error ()));
  65     free (name);
  66     core_bfd = NULL;
  67 #ifdef CLEAR_SOLIB
  68     CLEAR_SOLIB ();
  69 #endif
  70     if (core_ops.to_sections) {
  71       free ((PTR)core_ops.to_sections);
  72       core_ops.to_sections = NULL;
  73       core_ops.to_sections_end = NULL;
  74     }
  75   }
  76 }
  77
  78 #ifdef SOLIB_ADD
  79 /* Stub function for catch_errors around shared library hacking.  FROM_TTYP
  80    is really an int * which points to from_tty.  */
  81
  82 static int
  83 solib_add_stub (from_ttyp)
  84      char *from_ttyp;
  85 {
  86   SOLIB_ADD (NULL, *(int *)from_ttyp, &current_target);
  87   return 0;
  88 }
  89 #endif /* SOLIB_ADD */
  90
  91 /* Look for sections whose names start with `.reg/' so that we can extract the
  92    list of threads in a core file.  */
  93
  94 static void
  95 add_to_thread_list (abfd, asect, reg_sect_arg)
  96      bfd *abfd;
  97      asection *asect;
  98      PTR reg_sect_arg;
  99 {
 100   int thread_id;
 101   asection *reg_sect = (asection *) reg_sect_arg;
 102
 103   if (strncmp (bfd_section_name (abfd, asect), ".reg/", 5) != 0)
 104     return;
 105
 106   thread_id = atoi (bfd_section_name (abfd, asect) + 5);
 107
 108   add_thread (thread_id);
 109
 110 /* Warning, Will Robinson, looking at BFD private data! */
 111
 112   if (asect->filepos == reg_sect->filepos) /* Did we find .reg? */
 113     inferior_pid = thread_id;   /* Yes, make it current */
 114 }
 115
 116 /* This routine opens and sets up the core file bfd */
 117
 118 void
 119 core_open (filename, from_tty)
 120      char *filename;
 121      int from_tty;
 122 {
 123   const char *p;
 124   int siggy;
 125   struct cleanup *old_chain;
 126   char *temp;
 127   bfd *temp_bfd;
 128   int ontop;
 129   int scratch_chan;
 130
 131   target_preopen (from_tty);
 132   if (!filename)
 133     {
 134       error (core_bfd?
 135        "No core file specified.  (Use `detach' to stop debugging a core file.)"
 136      : "No core file specified.");
 137     }
 138
 139   filename = tilde_expand (filename);
 140   if (filename[0] != '/') {
 141     temp = concat (current_directory, "/", filename, NULL);
 142     free (filename);
 143     filename = temp;
 144   }
 145
 146   old_chain = make_cleanup (free, filename);
 147
 148   scratch_chan = open (filename, write_files? O_RDWR: O_RDONLY, 0);
 149   if (scratch_chan < 0)
 150     perror_with_name (filename);
 151
 152   temp_bfd = bfd_fdopenr (filename, gnutarget, scratch_chan);
 153   if (temp_bfd == NULL)
 154     {
 155       perror_with_name (filename);
 156     }
 157
 158   if (!bfd_check_format (temp_bfd, bfd_core))
 159     {
 160       /* Do it after the err msg */
 161       /* FIXME: should be checking for errors from bfd_close (for one thing,
 162          on error it does not free all the storage associated with the
 163          bfd).  */
 164       make_cleanup (bfd_close, temp_bfd);
 165       error ("\"%s\" is not a core dump: %s", filename, bfd_errmsg(bfd_get_error ()));
 166     }
 167
 168   /* Looks semi-reasonable.  Toss the old core file and work on the new.  */
 169
 170   discard_cleanups (old_chain);         /* Don't free filename any more */
 171   unpush_target (&core_ops);
 172   core_bfd = temp_bfd;
 173   old_chain = make_cleanup (core_close, core_bfd);
 174
 175   validate_files ();
 176
 177   /* Find the data section */
 178   if (build_section_table (core_bfd, &core_ops.to_sections,
 179                            &core_ops.to_sections_end))
 180     error ("Can't find sections in `%s': %s", bfd_get_filename(core_bfd),
 181            bfd_errmsg (bfd_get_error ()));
 182
 183   ontop = !push_target (&core_ops);
 184   discard_cleanups (old_chain);
 185
 186   p = bfd_core_file_failing_command (core_bfd);
 187   if (p)
 188     printf_filtered ("Core was generated by `%s'.\n", p);
 189
 190   siggy = bfd_core_file_failing_signal (core_bfd);
 191   if (siggy > 0)
 192     printf_filtered ("Program terminated with signal %d, %s.\n", siggy,
 193             safe_strsignal (siggy));
 194
 195   /* Build up thread list from BFD sections. */
 196
 197   init_thread_list ();
 198   bfd_map_over_sections (core_bfd, add_to_thread_list,
 199                          bfd_get_section_by_name (core_bfd, ".reg"));
 200
 201   if (ontop) {
 202     /* Fetch all registers from core file */
 203     target_fetch_registers (-1);
 204
 205     /* Add symbols and section mappings for any shared libraries */
 206 #ifdef SOLIB_ADD
 207     catch_errors (solib_add_stub, &from_tty, (char *)0,
 208                   RETURN_MASK_ALL);
 209
 210     /* solib_add_stub usually modifies current_target.to_sections, which
 211        has to be reflected in core_ops to enable proper freeing of
 212        the to_sections vector in core_close and correct section
 213        mapping in xfer_memory and core_files_info.  */
 214     core_ops.to_sections = current_target.to_sections;
 215     core_ops.to_sections_end = current_target.to_sections_end;
 216 #endif
 217
 218     /* Now, set up the frame cache, and print the top of stack */
 219     flush_cached_frames ();
 220     select_frame (get_current_frame (), 0);
 221     print_stack_frame (selected_frame, selected_frame_level, 1);
 222   } else {
 223     warning (
 224 "you won't be able to access this core file until you terminate\n\
 225 your %s; do ``info files''", target_longname);
 226   }
 227 }
 228
 229 void
 230 core_detach (args, from_tty)
 231      char *args;
 232      int from_tty;
 233 {
 234   if (args)
 235     error ("Too many arguments");
 236   unpush_target (&core_ops);
 237   reinit_frame_cache ();
 238   if (from_tty)
 239     printf_filtered ("No core file now.\n");
 240 }
 241
 242 /* Get the registers out of a core file.  This is the machine-
 243    independent part.  Fetch_core_registers is the machine-dependent
 244    part, typically implemented in the xm-file for each architecture.  */
 245
 246 /* We just get all the registers, so we don't use regno.  */
 247 /* ARGSUSED */
 248 static void
 249 get_core_registers (regno)
 250      int regno;
 251 {
 252   sec_ptr reg_sec;
 253   unsigned size;
 254   char *the_regs;
 255   char secname[10];
 256
 257   /* Thread support.  If inferior_pid is non-zero, then we have found a core
 258      file with threads (or multiple processes).  In that case, we need to
 259      use the appropriate register section, else we just use `.reg'. */
 260
 261   /* XXX - same thing needs to be done for floating-point (.reg2) sections. */
 262
 263   if (inferior_pid)
 264     sprintf (secname, ".reg/%d", inferior_pid);
 265   else
 266     strcpy (secname, ".reg");
 267
 268   reg_sec = bfd_get_section_by_name (core_bfd, secname);
 269   if (!reg_sec) goto cant;
 270   size = bfd_section_size (core_bfd, reg_sec);
 271   the_regs = alloca (size);
 272   if (bfd_get_section_contents (core_bfd, reg_sec, the_regs, (file_ptr)0, size))
 273     {
 274       fetch_core_registers (the_regs, size, 0,
 275                             (unsigned) bfd_section_vma (abfd,reg_sec));
 276     }
 277   else
 278     {
 279 cant:
 280       fprintf_filtered (gdb_stderr, "Couldn't fetch registers from core file: %s\n",
 281                bfd_errmsg (bfd_get_error ()));
 282     }
 283
 284   /* Now do it again for the float registers, if they exist.  */
 285   reg_sec = bfd_get_section_by_name (core_bfd, ".reg2");
 286   if (reg_sec) {
 287     size = bfd_section_size (core_bfd, reg_sec);
 288     the_regs = alloca (size);
 289     if (bfd_get_section_contents (core_bfd, reg_sec, the_regs, (file_ptr)0,
 290                                   size))
 291       {
 292         fetch_core_registers (the_regs, size, 2,
 293                               (unsigned) bfd_section_vma (abfd,reg_sec));
 294       }
 295     else
 296       {
 297         fprintf_filtered (gdb_stderr, "Couldn't fetch register set 2 from core file: %s\n",
 298                  bfd_errmsg (bfd_get_error ()));
 299       }
 300   }
 301   registers_fetched();
 302 }
 303
 304 static void
 305 core_files_info (t)
 306   struct target_ops *t;
 307 {
 308   print_section_info (t, core_bfd);
 309 }
 310 \f
 311 /* If mourn is being called in all the right places, this could be say
 312    `gdb internal error' (since generic_mourn calls breakpoint_init_inferior).  */
 313
 314 static int
 315 ignore (addr, contents)
 316      CORE_ADDR addr;
 317      char *contents;
 318 {
 319   return 0;
 320 }
 321
 322 struct target_ops core_ops = {
 323         "core", "Local core dump file",
 324         "Use a core file as a target.  Specify the filename of the core file.",
 325         core_open, core_close,
 326         find_default_attach, core_detach, 0, 0, /* resume, wait */
 327         get_core_registers,
 328         0, 0, /* store_regs, prepare_to_store */
 329         xfer_memory, core_files_info,
 330         ignore, ignore, /* core_insert_breakpoint, core_remove_breakpoint, */
 331         0, 0, 0, 0, 0, /* terminal stuff */
 332         0, 0, 0, /* kill, load, lookup sym */
 333         find_default_create_inferior, 0, /* mourn_inferior */
 334         0, /* can_run */
 335         0, /* notice_signals */
 336         core_stratum, 0, /* next */
 337         0, 1, 1, 1, 0,  /* all mem, mem, stack, regs, exec */
 338         0, 0,                   /* section pointers */
 339         OPS_MAGIC,              /* Always the last thing */
 340 };
 341
 342 void
 343 _initialize_corelow()
 344 {
 345   add_target (&core_ops);
 346 }