gdb/i386lynx-nat.c

   1 /* Native-dependent code for Lynx running on i386's, for GDB.
   2    Copyright 1988, 1989, 1991, 1992, 1993
   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 "frame.h"
  23 #include "inferior.h"
  24 #include "gdbcore.h"
  25 #include "target.h"
  26
  27 #include <sys/ptrace.h>
  28 #include "/usr/include/sys/wait.h"
  29
  30 /* these values indicate the offset of the named register in the econtext
  31    structure */
  32
  33 #define EAX     10
  34 #define ECX     9
  35 #define EDX     8
  36 #define EBX     7
  37 #define ESP     16
  38 #define EBP     5
  39 #define ESI     4
  40 #define EDI     3
  41 #define EIP     13
  42 #define EFL     15
  43 #define CS      14
  44 #define SS      17
  45 #define DS      2
  46 #define ES      1
  47
  48 /* Currently these are not being used. So set them to 0 */
  49
  50 #define FS      0
  51 #define GS      0
  52
  53 static struct target_ops lynx_core_ops;
  54
  55 /* this table must line up with REGISTER_NAMES in m-i386.h */
  56 static unsigned int regmap[] =
  57 {
  58   EAX, ECX, EDX, EBX,
  59   ESP, EBP, ESI, EDI,
  60   EIP, EFL, CS, SS,
  61   DS, ES, FS, GS,
  62 };
  63
  64 /* Return the address in the core dump or inferior of register REGNO.
  65    BLOCKEND is the address of the econtext structure */
  66
  67 static unsigned int
  68 register_addr (regno, blockend)
  69      int regno, blockend;
  70 {
  71   if (regno < 0 || regno >= NUM_REGS)
  72     error ("Invalid register number %d.", regno);
  73
  74   return (blockend + regmap[regno] * sizeof (long));
  75 }
  76
  77 /* Fetch one register.  */
  78
  79 static void
  80 fetch_register (regno, offset, bpid)
  81      int regno, bpid;
  82      unsigned int offset;
  83 {
  84   unsigned int regaddr;
  85   char buf[MAX_REGISTER_RAW_SIZE];
  86   char mess[128];                               /* For messages */
  87   int i;
  88
  89   regaddr = register_addr (regno, offset);
  90   for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
  91     {
  92       errno = 0;
  93       *(int *) &buf[i] = ptrace (PTRACE_PEEKTHREAD, bpid,
  94                                  (PTRACE_ARG3_TYPE) regaddr, 0);
  95       regaddr += sizeof (int);
  96       if (errno != 0)
  97         {
  98           sprintf (mess, "reading register %s (#%d)", reg_names[regno], regno);
  99           perror_with_name (mess);
 100         }
 101     }
 102   supply_register (regno, buf);
 103 }
 104
 105 /* Store our register values back into the inferior.
 106    If REGNO is -1, do this for all registers.
 107    Otherwise, REGNO specifies which register (so we can save time).  */
 108
 109 static void
 110 store_register (regno, offset, bpid)
 111      int regno, bpid;
 112      unsigned int offset;
 113 {
 114   unsigned int regaddr;
 115   char mess[128];
 116   extern char registers[];
 117   int i;
 118
 119   regaddr = register_addr (regno, offset);
 120   for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof(int))
 121     {
 122       errno = 0;
 123       ptrace (PTRACE_POKEUSER, bpid, (PTRACE_ARG3_TYPE) regaddr,
 124               *(int *) &registers[REGISTER_BYTE (regno) + i]);
 125       if (errno != 0)
 126         {
 127           sprintf (mess, "writing register number %d(%d)", regno, i);
 128           perror_with_name (mess);
 129         }
 130       regaddr += sizeof(int);
 131     }
 132 }
 133
 134 /* return an offset for use with register_addr() */
 135
 136 static unsigned int
 137 fetch_offset (pid)
 138     int pid;
 139 {
 140   struct st_entry s;
 141   unsigned int specpage_off, offset = (char *) &s.ecp - (char *) &s;
 142
 143   errno = 0;
 144   specpage_off = ptrace (PTRACE_THREADUSER, pid, (PTRACE_ARG3_TYPE) 0, 0);
 145   if (errno != 0)
 146     perror_with_name ("ptrace");
 147   errno = 0;
 148   offset = ptrace (PTRACE_PEEKTHREAD, pid, (PTRACE_ARG3_TYPE) offset, 0)
 149       - specpage_off;
 150   if (errno != 0)
 151     perror_with_name ("ptrace");
 152   return offset;
 153 }
 154
 155 /* Fetch all registers, or just one, from the child process.  */
 156
 157 void
 158 fetch_inferior_registers (regno)
 159      int regno;
 160 {
 161   unsigned int offset = fetch_offset (inferior_pid);
 162
 163   if (regno == -1)
 164     {
 165       for (regno = 0; regno < NUM_REGS; regno++)
 166         fetch_register (regno, offset, inferior_pid);
 167     }
 168   else
 169     fetch_register (regno, offset, inferior_pid);
 170 }
 171
 172 /* Store all registers, or just one, to the child process.  */
 173
 174 void
 175 store_inferior_registers (regno)
 176      int regno;
 177 {
 178     unsigned int offset = fetch_offset (inferior_pid);
 179
 180     if (regno == -1)
 181       {
 182         for (regno = 0; regno < NUM_REGS; regno++)
 183           store_register (regno, offset, inferior_pid);
 184       }
 185     else
 186       store_register (regno, offset, inferior_pid);
 187 }
 188
 189 /* Wait for child to do something.  Return pid of child, or -1 in case
 190    of error; store status through argument pointer STATUS.  */
 191
 192 int
 193 child_wait (status)
 194      int *status;
 195 {
 196   int pid;
 197   int save_errno;
 198   int thread;
 199
 200   while (1)
 201     {
 202       int sig;
 203
 204       if (attach_flag)
 205         set_sigint_trap();      /* Causes SIGINT to be passed on to the
 206                                    attached process. */
 207       pid = wait (status);
 208       save_errno = errno;
 209
 210       if (attach_flag)
 211         clear_sigint_trap();
 212
 213       if (pid == -1)
 214         {
 215           if (save_errno == EINTR)
 216             continue;
 217           fprintf (stderr, "Child process unexpectedly missing: %s.\n",
 218                    safe_strerror (save_errno));
 219           *status = 42;         /* Claim it exited with signal 42 */
 220           return -1;
 221         }
 222
 223       if (pid != PIDGET (inferior_pid)) /* Some other process?!? */
 224         continue;
 225
 226 /*      thread = WIFTID (*status);*/
 227       thread = *status >> 16;
 228
 229       /* Initial thread value can only be acquired via wait, so we have to
 230          resort to this hack.  */
 231
 232       if (TIDGET (inferior_pid) == 0)
 233         {
 234           inferior_pid = BUILDPID (inferior_pid, thread);
 235           add_thread (inferior_pid);
 236         }
 237
 238       pid = BUILDPID (pid, thread);
 239
 240       return pid;
 241     }
 242 }
 243
 244 /* Convert a Lynx process ID to a string.  Returns the string in a static
 245    buffer.  */
 246
 247 char *
 248 i386lynx_pid_to_str (pid)
 249      int pid;
 250 {
 251   static char buf[40];
 252
 253   sprintf (buf, "process %d thread %d", PIDGET (pid), TIDGET (pid));
 254
 255   return buf;
 256 }
 257
 258 /* Extract the register values out of the core file and store
 259    them where `read_register' will find them.
 260
 261    CORE_REG_SECT points to the register values themselves, read into memory.
 262    CORE_REG_SIZE is the size of that area.
 263    WHICH says which set of registers we are handling (0 = int, 2 = float
 264          on machines where they are discontiguous).
 265    REG_ADDR is the offset from u.u_ar0 to the register values relative to
 266             core_reg_sect.  This is used with old-fashioned core files to
 267             locate the registers in a large upage-plus-stack ".reg" section.
 268             Original upage address X is at location core_reg_sect+x+reg_addr.
 269  */
 270
 271 void
 272 fetch_core_registers (core_reg_sect, core_reg_size, which, reg_addr)
 273      char *core_reg_sect;
 274      unsigned core_reg_size;
 275      int which;
 276      unsigned reg_addr;
 277 {
 278   struct st_entry s;
 279   unsigned int regno, addr;
 280
 281   for (regno = 0; regno < NUM_REGS; regno++)
 282     {
 283       addr = register_addr (regno, (char *) &s.ec - (char *) &s);
 284       supply_register (regno, core_reg_sect + addr);
 285     }
 286 }
 287
 288 #if 0
 289
 290 /* Discard all vestiges of any previous core file
 291    and mark data and stack spaces as empty.  */
 292
 293 /* ARGSUSED */
 294 static void
 295 lynx_core_close (quitting)
 296      int quitting;
 297 {
 298   if (core_bfd)
 299     {
 300       free (bfd_get_filename (core_bfd));
 301       bfd_close (core_bfd);
 302       core_bfd = NULL;
 303
 304       if (core_ops.to_sections)
 305         {
 306           free ((PTR)lynx_core_ops.to_sections);
 307           lynx_core_ops.to_sections = NULL;
 308           lynx_core_ops.to_sections_end = NULL;
 309         }
 310     }
 311 }
 312
 313 /* This routine opens and sets up the core file bfd */
 314
 315 static void
 316 lynx_core_open (filename, from_tty)
 317      char *filename;
 318      int from_tty;
 319 {
 320   const char *p;
 321   int siggy;
 322   struct cleanup *old_chain;
 323   char *temp;
 324   bfd *temp_bfd;
 325   int ontop;
 326   int scratch_chan;
 327
 328   target_preopen (from_tty);
 329   if (!filename)
 330     {
 331       error (core_bfd ?
 332              "No core file specified.  (Use `detach' to stop debugging a core file.)"
 333              : "No core file specified.");
 334     }
 335
 336   filename = tilde_expand (filename);
 337   if (filename[0] != '/')
 338     {
 339       temp = concat (current_directory, "/", filename, NULL);
 340       free (filename);
 341       filename = temp;
 342     }
 343
 344   old_chain = make_cleanup (free, filename);
 345
 346   scratch_chan = open (filename, write_files? O_RDWR: O_RDONLY, 0);
 347   if (scratch_chan < 0)
 348     perror_with_name (filename);
 349
 350   temp_bfd = bfd_fdopenr (filename, NULL, scratch_chan);
 351   if (temp_bfd == NULL)
 352     perror_with_name (filename);
 353
 354   if (!bfd_check_format (temp_bfd, bfd_core))
 355     {
 356       /* Do it after the err msg */
 357       make_cleanup (bfd_close, temp_bfd);
 358       error ("\"%s\" is not a core dump: %s", filename, bfd_errmsg(bfd_error));
 359     }
 360
 361   /* Looks semi-reasonable.  Toss the old core file and work on the new.  */
 362
 363   discard_cleanups (old_chain);         /* Don't free filename any more */
 364   unpush_target (&core_ops);
 365   core_bfd = temp_bfd;
 366   old_chain = make_cleanup (core_close, core_bfd);
 367
 368   validate_files ();
 369
 370   /* Find the data section */
 371   if (build_section_table (core_bfd, &core_ops.to_sections,
 372                            &core_ops.to_sections_end))
 373     error ("Can't find sections in `%s': %s", bfd_get_filename(core_bfd),
 374            bfd_errmsg (bfd_error));
 375
 376   ontop = !push_target (&core_ops);
 377   discard_cleanups (old_chain);
 378
 379   p = bfd_core_file_failing_command (core_bfd);
 380   if (p)
 381     printf_filtered ("Core was generated by `%s'.\n", p);
 382
 383   siggy = bfd_core_file_failing_signal (core_bfd);
 384   if (siggy > 0)
 385     printf_filtered ("Program terminated with signal %d, %s.\n", siggy,
 386             safe_strsignal (siggy));
 387
 388   /* Locate all of the thread register sections.  They have names like .regxx,
 389      where xx is the thread-id.  */
 390
 391   bfd_map_over_sections (core_bfd, grok_register_sections,
 392
 393   if (ontop)
 394     {
 395       /* Fetch all registers from core file */
 396       target_fetch_registers (-1);
 397
 398       /* Now, set up the frame cache, and print the top of stack */
 399       set_current_frame (create_new_frame (read_fp (),
 400                                            read_pc ()));
 401       select_frame (get_current_frame (), 0);
 402       print_stack_frame (selected_frame, selected_frame_level, 1);
 403     }
 404   else
 405     {
 406       warning (
 407                "you won't be able to access this core file until you terminate\n\
 408 your %s; do ``info files''", current_target->to_longname);
 409     }
 410 }
 411
 412 static void
 413 lynx_core_detach (args, from_tty)
 414      char *args;
 415      int from_tty;
 416 {
 417   if (args)
 418     error ("Too many arguments");
 419   unpush_target (&core_ops);
 420   if (from_tty)
 421     printf_filtered ("No core file now.\n");
 422 }
 423
 424 /* Get the registers out of a core file.  This is the machine-
 425    independent part.  Fetch_core_registers is the machine-dependent
 426    part, typically implemented in the xm-file for each architecture.  */
 427
 428 /* We just get all the registers, so we don't use regno.  */
 429 /* ARGSUSED */
 430 static void
 431 get_core_registers (regno)
 432      int regno;
 433 {
 434   sec_ptr reg_sec;
 435   unsigned size;
 436   char *the_regs;
 437   char regsecname[20];
 438
 439   sprintf (regsecname, ".reg%d", TIDGET (inferior_pid));
 440
 441   reg_sec = bfd_get_section_by_name (core_bfd, regsecname);
 442   if (!reg_sec)
 443     goto cant;
 444   size = bfd_section_size (core_bfd, reg_sec);
 445   the_regs = alloca (size);
 446   if (bfd_get_section_contents (core_bfd, reg_sec, the_regs, (file_ptr)0,
 447                                 size))
 448     {
 449       fetch_core_registers (the_regs, size, 0,
 450                             (unsigned) bfd_section_vma (abfd,reg_sec));
 451     }
 452   else
 453     {
 454 cant:
 455       fprintf_filtered (stderr, "Couldn't fetch registers from core file: %s\n",
 456                bfd_errmsg (bfd_error));
 457     }
 458
 459   registers_fetched();
 460 }
 461
 462 static void
 463 core_files_info (t)
 464   struct target_ops *t;
 465 {
 466   print_section_info (t, core_bfd);
 467 }
 468 \f
 469 /* If mourn is being called in all the right places, this could be say
 470    `gdb internal error' (since generic_mourn calls mark_breakpoints_out).  */
 471
 472 static int
 473 ignore (addr, contents)
 474      CORE_ADDR addr;
 475      char *contents;
 476 {
 477 }
 478
 479 static struct target_ops
 480 lynx_core_ops =
 481 {
 482   "core",
 483   "Local core dump file",
 484   "Use a core file as a target.  Specify the filename of the core file.",
 485   lynx_core_open,
 486   lynx_core_close,
 487   find_default_attach,
 488   lynx_core_detach,
 489   0,
 490   0,
 491   get_core_registers,
 492   0,
 493   0,
 494   xfer_memory,
 495   lynx_core_files_info,
 496   ignore,
 497   ignore,
 498   0,
 499   0,
 500   0,
 501   0,
 502   0,
 503   0,
 504   0,
 505   0,
 506   find_default_create_inferior,
 507   0,                            /* mourn_inferior */
 508   0,                            /* can_run */
 509   0,                            /* notice_signals */
 510   core_stratum,
 511   0,                            /* next */
 512   0,
 513   1,
 514   1,
 515   1,
 516   0,
 517   0,
 518   0,
 519   OPS_MAGIC,                    /* Always the last thing */
 520 };
 521
 522 void
 523 _initialize_i386lynx_nat()
 524 {
 525   add_target (&lynx_core_ops);
 526 }
 527 #endif