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