gdb/go32-nat.c

   1 /* Native debugging support for Intel x86 running DJGPP.
   2    Copyright 1997, 1999, 2000, 2001 Free Software Foundation, Inc.
   3    Written by Robert Hoehne.
   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., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include <fcntl.h>
  23
  24 #include "defs.h"
  25 #include "inferior.h"
  26 #include "gdb_wait.h"
  27 #include "gdbcore.h"
  28 #include "command.h"
  29 #include "floatformat.h"
  30 #include "buildsym.h"
  31 #include "i387-nat.h"
  32 #include "value.h"
  33 #include "regcache.h"
  34 #include "gdb_string.h"
  35
  36 #include <stdio.h>              /* required for __DJGPP_MINOR__ */
  37 #include <stdlib.h>
  38 #include <errno.h>
  39 #include <unistd.h>
  40 #include <io.h>
  41 #include <dpmi.h>
  42 #include <debug/v2load.h>
  43 #include <debug/dbgcom.h>
  44 #if __DJGPP_MINOR__ > 2
  45 #include <debug/redir.h>
  46 #endif
  47
  48 #if __DJGPP_MINOR__ < 3
  49 /* This code will be provided from DJGPP 2.03 on. Until then I code it
  50    here */
  51 typedef struct
  52   {
  53     unsigned short sig0;
  54     unsigned short sig1;
  55     unsigned short sig2;
  56     unsigned short sig3;
  57     unsigned short exponent:15;
  58     unsigned short sign:1;
  59   }
  60 NPXREG;
  61
  62 typedef struct
  63   {
  64     unsigned int control;
  65     unsigned int status;
  66     unsigned int tag;
  67     unsigned int eip;
  68     unsigned int cs;
  69     unsigned int dataptr;
  70     unsigned int datasel;
  71     NPXREG reg[8];
  72   }
  73 NPX;
  74
  75 static NPX npx;
  76
  77 static void save_npx (void);    /* Save the FPU of the debugged program */
  78 static void load_npx (void);    /* Restore the FPU of the debugged program */
  79
  80 /* ------------------------------------------------------------------------- */
  81 /* Store the contents of the NPX in the global variable `npx'.  */
  82 /* *INDENT-OFF* */
  83
  84 static void
  85 save_npx (void)
  86 {
  87   asm ("inb    $0xa0, %%al
  88        testb $0x20, %%al
  89        jz 1f
  90        xorb %% al, %%al
  91        outb %% al, $0xf0
  92        movb $0x20, %%al
  93        outb %% al, $0xa0
  94        outb %% al, $0x20
  95 1:
  96        fnsave % 0
  97        fwait "
  98 :     "=m" (npx)
  99 :                               /* No input */
 100 :     "%eax");
 101 }
 102
 103 /* *INDENT-ON* */
 104
 105
 106
 107
 108
 109 /* ------------------------------------------------------------------------- */
 110 /* Reload the contents of the NPX from the global variable `npx'.  */
 111
 112 static void
 113 load_npx (void)
 114 {
 115   asm ("frstor %0":"=m" (npx));
 116 }
 117 /* ------------------------------------------------------------------------- */
 118 /* Stubs for the missing redirection functions.  */
 119 typedef struct {
 120   char *command;
 121   int redirected;
 122 } cmdline_t;
 123
 124 void
 125 redir_cmdline_delete (cmdline_t *ptr)
 126 {
 127   ptr->redirected = 0;
 128 }
 129
 130 int
 131 redir_cmdline_parse (const char *args, cmdline_t *ptr)
 132 {
 133   return -1;
 134 }
 135
 136 int
 137 redir_to_child (cmdline_t *ptr)
 138 {
 139   return 1;
 140 }
 141
 142 int
 143 redir_to_debugger (cmdline_t *ptr)
 144 {
 145   return 1;
 146 }
 147
 148 int
 149 redir_debug_init (cmdline_t *ptr)
 150 {
 151   return 0;
 152 }
 153 #endif /* __DJGPP_MINOR < 3 */
 154
 155 typedef enum { wp_insert, wp_remove, wp_count } wp_op;
 156
 157 /* This holds the current reference counts for each debug register.  */
 158 static int dr_ref_count[4];
 159
 160 #define SOME_PID 42
 161
 162 static int prog_has_started = 0;
 163 static void go32_open (char *name, int from_tty);
 164 static void go32_close (int quitting);
 165 static void go32_attach (char *args, int from_tty);
 166 static void go32_detach (char *args, int from_tty);
 167 static void go32_resume (ptid_t ptid, int step,
 168                          enum target_signal siggnal);
 169 static ptid_t go32_wait (ptid_t ptid,
 170                                struct target_waitstatus *status);
 171 static void go32_fetch_registers (int regno);
 172 static void store_register (int regno);
 173 static void go32_store_registers (int regno);
 174 static void go32_prepare_to_store (void);
 175 static int go32_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len,
 176                              int write,
 177                              struct mem_attrib *attrib,
 178                              struct target_ops *target);
 179 static void go32_files_info (struct target_ops *target);
 180 static void go32_stop (void);
 181 static void go32_kill_inferior (void);
 182 static void go32_create_inferior (char *exec_file, char *args, char **env);
 183 static void go32_mourn_inferior (void);
 184 static int go32_can_run (void);
 185
 186 static struct target_ops go32_ops;
 187 static void go32_terminal_init (void);
 188 static void go32_terminal_inferior (void);
 189 static void go32_terminal_ours (void);
 190
 191 #define r_ofs(x) (offsetof(TSS,x))
 192
 193 static struct
 194 {
 195   size_t tss_ofs;
 196   size_t size;
 197 }
 198 regno_mapping[] =
 199 {
 200   {r_ofs (tss_eax), 4}, /* normal registers, from a_tss */
 201   {r_ofs (tss_ecx), 4},
 202   {r_ofs (tss_edx), 4},
 203   {r_ofs (tss_ebx), 4},
 204   {r_ofs (tss_esp), 4},
 205   {r_ofs (tss_ebp), 4},
 206   {r_ofs (tss_esi), 4},
 207   {r_ofs (tss_edi), 4},
 208   {r_ofs (tss_eip), 4},
 209   {r_ofs (tss_eflags), 4},
 210   {r_ofs (tss_cs), 2},
 211   {r_ofs (tss_ss), 2},
 212   {r_ofs (tss_ds), 2},
 213   {r_ofs (tss_es), 2},
 214   {r_ofs (tss_fs), 2},
 215   {r_ofs (tss_gs), 2},
 216   {0, 10},              /* 8 FP registers, from npx.reg[] */
 217   {1, 10},
 218   {2, 10},
 219   {3, 10},
 220   {4, 10},
 221   {5, 10},
 222   {6, 10},
 223   {7, 10},
 224         /* The order of the next 7 registers must be consistent
 225            with their numbering in config/i386/tm-i386.h, which see.  */
 226   {0, 2},               /* control word, from npx */
 227   {4, 2},               /* status word, from npx */
 228   {8, 2},               /* tag word, from npx */
 229   {16, 2},              /* last FP exception CS from npx */
 230   {12, 4},              /* last FP exception EIP from npx */
 231   {24, 2},              /* last FP exception operand selector from npx */
 232   {20, 4},              /* last FP exception operand offset from npx */
 233   {18, 2}               /* last FP opcode from npx */
 234 };
 235
 236 static struct
 237   {
 238     int go32_sig;
 239     enum target_signal gdb_sig;
 240   }
 241 sig_map[] =
 242 {
 243   {0, TARGET_SIGNAL_FPE},
 244   {1, TARGET_SIGNAL_TRAP},
 245   /* Exception 2 is triggered by the NMI.  DJGPP handles it as SIGILL,
 246      but I think SIGBUS is better, since the NMI is usually activated
 247      as a result of a memory parity check failure.  */
 248   {2, TARGET_SIGNAL_BUS},
 249   {3, TARGET_SIGNAL_TRAP},
 250   {4, TARGET_SIGNAL_FPE},
 251   {5, TARGET_SIGNAL_SEGV},
 252   {6, TARGET_SIGNAL_ILL},
 253   {7, TARGET_SIGNAL_EMT},       /* no-coprocessor exception */
 254   {8, TARGET_SIGNAL_SEGV},
 255   {9, TARGET_SIGNAL_SEGV},
 256   {10, TARGET_SIGNAL_BUS},
 257   {11, TARGET_SIGNAL_SEGV},
 258   {12, TARGET_SIGNAL_SEGV},
 259   {13, TARGET_SIGNAL_SEGV},
 260   {14, TARGET_SIGNAL_SEGV},
 261   {16, TARGET_SIGNAL_FPE},
 262   {17, TARGET_SIGNAL_BUS},
 263   {31, TARGET_SIGNAL_ILL},
 264   {0x1b, TARGET_SIGNAL_INT},
 265   {0x75, TARGET_SIGNAL_FPE},
 266   {0x78, TARGET_SIGNAL_ALRM},
 267   {0x79, TARGET_SIGNAL_INT},
 268   {0x7a, TARGET_SIGNAL_QUIT},
 269   {-1, TARGET_SIGNAL_LAST}
 270 };
 271
 272 static struct {
 273   enum target_signal gdb_sig;
 274   int djgpp_excepno;
 275 } excepn_map[] = {
 276   {TARGET_SIGNAL_0, -1},
 277   {TARGET_SIGNAL_ILL, 6},       /* Invalid Opcode */
 278   {TARGET_SIGNAL_EMT, 7},       /* triggers SIGNOFP */
 279   {TARGET_SIGNAL_SEGV, 13},     /* GPF */
 280   {TARGET_SIGNAL_BUS, 17},      /* Alignment Check */
 281   /* The rest are fake exceptions, see dpmiexcp.c in djlsr*.zip for
 282      details.  */
 283   {TARGET_SIGNAL_TERM, 0x1b},   /* triggers Ctrl-Break type of SIGINT */
 284   {TARGET_SIGNAL_FPE, 0x75},
 285   {TARGET_SIGNAL_INT, 0x79},
 286   {TARGET_SIGNAL_QUIT, 0x7a},
 287   {TARGET_SIGNAL_ALRM, 0x78},   /* triggers SIGTIMR */
 288   {TARGET_SIGNAL_PROF, 0x78},
 289   {TARGET_SIGNAL_LAST, -1}
 290 };
 291
 292 static void
 293 go32_open (char *name, int from_tty)
 294 {
 295   printf_unfiltered ("Done.  Use the \"run\" command to run the program.\n");
 296 }
 297
 298 static void
 299 go32_close (int quitting)
 300 {
 301 }
 302
 303 static void
 304 go32_attach (char *args, int from_tty)
 305 {
 306   error ("\
 307 You cannot attach to a running program on this platform.\n\
 308 Use the `run' command to run DJGPP programs.");
 309 }
 310
 311 static void
 312 go32_detach (char *args, int from_tty)
 313 {
 314 }
 315
 316 static int resume_is_step;
 317 static int resume_signal = -1;
 318
 319 static void
 320 go32_resume (ptid_t ptid, int step, enum target_signal siggnal)
 321 {
 322   int i;
 323
 324   resume_is_step = step;
 325
 326   if (siggnal != TARGET_SIGNAL_0 && siggnal != TARGET_SIGNAL_TRAP)
 327   {
 328     for (i = 0, resume_signal = -1;
 329          excepn_map[i].gdb_sig != TARGET_SIGNAL_LAST; i++)
 330       if (excepn_map[i].gdb_sig == siggnal)
 331       {
 332         resume_signal = excepn_map[i].djgpp_excepno;
 333         break;
 334       }
 335     if (resume_signal == -1)
 336       printf_unfiltered ("Cannot deliver signal %s on this platform.\n",
 337                          target_signal_to_name (siggnal));
 338   }
 339 }
 340
 341 static char child_cwd[FILENAME_MAX];
 342
 343 static int
 344 go32_wait (ptid_t ptid, struct target_waitstatus *status)
 345 {
 346   int i;
 347   unsigned char saved_opcode;
 348   unsigned long INT3_addr = 0;
 349   int stepping_over_INT = 0;
 350
 351   a_tss.tss_eflags &= 0xfeff;   /* reset the single-step flag (TF) */
 352   if (resume_is_step)
 353     {
 354       /* If the next instruction is INT xx or INTO, we need to handle
 355          them specially.  Intel manuals say that these instructions
 356          reset the single-step flag (a.k.a. TF).  However, it seems
 357          that, at least in the DPMI environment, and at least when
 358          stepping over the DPMI interrupt 31h, the problem is having
 359          TF set at all when INT 31h is executed: the debuggee either
 360          crashes (and takes the system with it) or is killed by a
 361          SIGTRAP.
 362
 363          So we need to emulate single-step mode: we put an INT3 opcode
 364          right after the INT xx instruction, let the debuggee run
 365          until it hits INT3 and stops, then restore the original
 366          instruction which we overwrote with the INT3 opcode, and back
 367          up the debuggee's EIP to that instruction.  */
 368       read_child (a_tss.tss_eip, &saved_opcode, 1);
 369       if (saved_opcode == 0xCD || saved_opcode == 0xCE)
 370         {
 371           unsigned char INT3_opcode = 0xCC;
 372
 373           INT3_addr
 374             = saved_opcode == 0xCD ? a_tss.tss_eip + 2 : a_tss.tss_eip + 1;
 375           stepping_over_INT = 1;
 376           read_child (INT3_addr, &saved_opcode, 1);
 377           write_child (INT3_addr, &INT3_opcode, 1);
 378         }
 379       else
 380         a_tss.tss_eflags |= 0x0100; /* normal instruction: set TF */
 381     }
 382
 383   /* The special value FFFFh in tss_trap indicates to run_child that
 384      tss_irqn holds a signal to be delivered to the debuggee.  */
 385   if (resume_signal <= -1)
 386     {
 387       a_tss.tss_trap = 0;
 388       a_tss.tss_irqn = 0xff;
 389     }
 390   else
 391     {
 392       a_tss.tss_trap = 0xffff;  /* run_child looks for this */
 393       a_tss.tss_irqn = resume_signal;
 394     }
 395
 396   /* The child might change working directory behind our back.  The
 397      GDB users won't like the side effects of that when they work with
 398      relative file names, and GDB might be confused by its current
 399      directory not being in sync with the truth.  So we always make a
 400      point of changing back to where GDB thinks is its cwd, when we
 401      return control to the debugger, but restore child's cwd before we
 402      run it.  */
 403   /* Initialize child_cwd, before the first call to run_child and not
 404      in the initialization, so the child get also the changed directory
 405      set with the gdb-command "cd ..." */
 406   if (!*child_cwd)
 407     /* Initialize child's cwd with the current one.  */
 408     getcwd (child_cwd, sizeof (child_cwd));
 409
 410   chdir (child_cwd);
 411
 412 #if __DJGPP_MINOR__ < 3
 413   load_npx ();
 414 #endif
 415   run_child ();
 416 #if __DJGPP_MINOR__ < 3
 417   save_npx ();
 418 #endif
 419
 420   /* Did we step over an INT xx instruction?  */
 421   if (stepping_over_INT && a_tss.tss_eip == INT3_addr + 1)
 422     {
 423       /* Restore the original opcode.  */
 424       a_tss.tss_eip--;  /* EIP points *after* the INT3 instruction */
 425       write_child (a_tss.tss_eip, &saved_opcode, 1);
 426       /* Simulate a TRAP exception.  */
 427       a_tss.tss_irqn = 1;
 428       a_tss.tss_eflags |= 0x0100;
 429     }
 430
 431   getcwd (child_cwd, sizeof (child_cwd)); /* in case it has changed */
 432   chdir (current_directory);
 433
 434   if (a_tss.tss_irqn == 0x21)
 435     {
 436       status->kind = TARGET_WAITKIND_EXITED;
 437       status->value.integer = a_tss.tss_eax & 0xff;
 438     }
 439   else
 440     {
 441       status->value.sig = TARGET_SIGNAL_UNKNOWN;
 442       status->kind = TARGET_WAITKIND_STOPPED;
 443       for (i = 0; sig_map[i].go32_sig != -1; i++)
 444         {
 445           if (a_tss.tss_irqn == sig_map[i].go32_sig)
 446             {
 447 #if __DJGPP_MINOR__ < 3
 448               if ((status->value.sig = sig_map[i].gdb_sig) !=
 449                   TARGET_SIGNAL_TRAP)
 450                 status->kind = TARGET_WAITKIND_SIGNALLED;
 451 #else
 452               status->value.sig = sig_map[i].gdb_sig;
 453 #endif
 454               break;
 455             }
 456         }
 457     }
 458   return SOME_PID;
 459 }
 460
 461 static void
 462 fetch_register (int regno)
 463 {
 464   if (regno < FP0_REGNUM)
 465     supply_register (regno, (char *) &a_tss + regno_mapping[regno].tss_ofs);
 466   else if (regno <= LAST_FPU_CTRL_REGNUM)
 467     i387_supply_register (regno, (char *) &npx);
 468   else
 469     internal_error (__FILE__, __LINE__,
 470                     "Invalid register no. %d in fetch_register.", regno);
 471 }
 472
 473 static void
 474 go32_fetch_registers (int regno)
 475 {
 476   if (regno >= 0)
 477     fetch_register (regno);
 478   else
 479     {
 480       for (regno = 0; regno < FP0_REGNUM; regno++)
 481         fetch_register (regno);
 482       i387_supply_fsave ((char *) &npx);
 483     }
 484 }
 485
 486 static void
 487 store_register (int regno)
 488 {
 489   void *rp;
 490   void *v = (void *) register_buffer (regno);
 491
 492   if (regno < FP0_REGNUM)
 493     memcpy ((char *) &a_tss + regno_mapping[regno].tss_ofs,
 494             v, regno_mapping[regno].size);
 495   else if (regno <= LAST_FPU_CTRL_REGNUM)
 496     i387_fill_fsave ((char *)&npx, regno);
 497   else
 498     internal_error (__FILE__, __LINE__,
 499                     "Invalid register no. %d in store_register.", regno);
 500 }
 501
 502 static void
 503 go32_store_registers (int regno)
 504 {
 505   unsigned r;
 506
 507   if (regno >= 0)
 508     store_register (regno);
 509   else
 510     {
 511       for (r = 0; r < FP0_REGNUM; r++)
 512         store_register (r);
 513       i387_fill_fsave ((char *) &npx, -1);
 514     }
 515 }
 516
 517 static void
 518 go32_prepare_to_store (void)
 519 {
 520 }
 521
 522 static int
 523 go32_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write,
 524                   struct mem_attrib *attrib, struct target_ops *target)
 525 {
 526   if (write)
 527     {
 528       if (write_child (memaddr, myaddr, len))
 529         {
 530           return 0;
 531         }
 532       else
 533         {
 534           return len;
 535         }
 536     }
 537   else
 538     {
 539       if (read_child (memaddr, myaddr, len))
 540         {
 541           return 0;
 542         }
 543       else
 544         {
 545           return len;
 546         }
 547     }
 548 }
 549
 550 static cmdline_t child_cmd;     /* parsed child's command line kept here */
 551
 552 static void
 553 go32_files_info (struct target_ops *target)
 554 {
 555   printf_unfiltered ("You are running a DJGPP V2 program.\n");
 556 }
 557
 558 static void
 559 go32_stop (void)
 560 {
 561   normal_stop ();
 562   cleanup_client ();
 563   inferior_ptid = null_ptid;
 564   prog_has_started = 0;
 565 }
 566
 567 static void
 568 go32_kill_inferior (void)
 569 {
 570   redir_cmdline_delete (&child_cmd);
 571   resume_signal = -1;
 572   resume_is_step = 0;
 573   unpush_target (&go32_ops);
 574 }
 575
 576 static void
 577 go32_create_inferior (char *exec_file, char *args, char **env)
 578 {
 579   extern char **environ;
 580   jmp_buf start_state;
 581   char *cmdline;
 582   char **env_save = environ;
 583
 584   /* If no exec file handed to us, get it from the exec-file command -- with
 585      a good, common error message if none is specified.  */
 586   if (exec_file == 0)
 587     exec_file = get_exec_file (1);
 588
 589   if (prog_has_started)
 590     {
 591       go32_stop ();
 592       go32_kill_inferior ();
 593     }
 594   resume_signal = -1;
 595   resume_is_step = 0;
 596
 597   /* Initialize child's cwd as empty to be initialized when starting
 598      the child.  */
 599   *child_cwd = 0;
 600
 601   /* Init command line storage.  */
 602   if (redir_debug_init (&child_cmd) == -1)
 603     internal_error (__FILE__, __LINE__,
 604                     "Cannot allocate redirection storage: not enough memory.\n");
 605
 606   /* Parse the command line and create redirections.  */
 607   if (strpbrk (args, "<>"))
 608     {
 609       if (redir_cmdline_parse (args, &child_cmd) == 0)
 610         args = child_cmd.command;
 611       else
 612         error ("Syntax error in command line.");
 613     }
 614   else
 615     child_cmd.command = xstrdup (args);
 616
 617   cmdline = (char *) alloca (strlen (args) + 4);
 618   cmdline[0] = strlen (args);
 619   strcpy (cmdline + 1, args);
 620   cmdline[strlen (args) + 1] = 13;
 621
 622   environ = env;
 623
 624   if (v2loadimage (exec_file, cmdline, start_state))
 625     {
 626       environ = env_save;
 627       printf_unfiltered ("Load failed for image %s\n", exec_file);
 628       exit (1);
 629     }
 630   environ = env_save;
 631
 632   edi_init (start_state);
 633 #if __DJGPP_MINOR__ < 3
 634   save_npx ();
 635 #endif
 636
 637   inferior_ptid = pid_to_ptid (SOME_PID);
 638   push_target (&go32_ops);
 639   clear_proceed_status ();
 640   insert_breakpoints ();
 641   proceed ((CORE_ADDR) -1, TARGET_SIGNAL_0, 0);
 642   prog_has_started = 1;
 643 }
 644
 645 static void
 646 go32_mourn_inferior (void)
 647 {
 648   /* We need to make sure all the breakpoint enable bits in the DR7
 649      register are reset when the inferior exits.  Otherwise, if they
 650      rerun the inferior, the uncleared bits may cause random SIGTRAPs,
 651      failure to set more watchpoints, and other calamities.  It would
 652      be nice if GDB itself would take care to remove all breakpoints
 653      at all times, but it doesn't, probably under an assumption that
 654      the OS cleans up when the debuggee exits.  */
 655   i386_cleanup_dregs ();
 656   go32_kill_inferior ();
 657   generic_mourn_inferior ();
 658 }
 659
 660 static int
 661 go32_can_run (void)
 662 {
 663   return 1;
 664 }
 665
 666 /* Hardware watchpoint support.  */
 667
 668 #define D_REGS edi.dr
 669 #define CONTROL D_REGS[7]
 670 #define STATUS D_REGS[6]
 671
 672 /* Pass the address ADDR to the inferior in the I'th debug register.
 673    Here we just store the address in D_REGS, the watchpoint will be
 674    actually set up when go32_wait runs the debuggee.  */
 675 void
 676 go32_set_dr (int i, CORE_ADDR addr)
 677 {
 678   if (i < 0 || i > 3)
 679     internal_error (__FILE__, __LINE__,
 680                     "Invalid register %d in go32_set_dr.\n", i);
 681   D_REGS[i] = addr;
 682 }
 683
 684 /* Pass the value VAL to the inferior in the DR7 debug control
 685    register.  Here we just store the address in D_REGS, the watchpoint
 686    will be actually set up when go32_wait runs the debuggee.  */
 687 void
 688 go32_set_dr7 (unsigned val)
 689 {
 690   CONTROL = val;
 691 }
 692
 693 /* Get the value of the DR6 debug status register from the inferior.
 694    Here we just return the value stored in D_REGS, as we've got it
 695    from the last go32_wait call.  */
 696 unsigned
 697 go32_get_dr6 (void)
 698 {
 699   return STATUS;
 700 }
 701
 702 /* Put the device open on handle FD into either raw or cooked
 703    mode, return 1 if it was in raw mode, zero otherwise.  */
 704
 705 static int
 706 device_mode (int fd, int raw_p)
 707 {
 708   int oldmode, newmode;
 709   __dpmi_regs regs;
 710
 711   regs.x.ax = 0x4400;
 712   regs.x.bx = fd;
 713   __dpmi_int (0x21, &regs);
 714   if (regs.x.flags & 1)
 715     return -1;
 716   newmode = oldmode = regs.x.dx;
 717
 718   if (raw_p)
 719     newmode |= 0x20;
 720   else
 721     newmode &= ~0x20;
 722
 723   if (oldmode & 0x80)   /* Only for character dev */
 724   {
 725     regs.x.ax = 0x4401;
 726     regs.x.bx = fd;
 727     regs.x.dx = newmode & 0xff;   /* Force upper byte zero, else it fails */
 728     __dpmi_int (0x21, &regs);
 729     if (regs.x.flags & 1)
 730       return -1;
 731   }
 732   return (oldmode & 0x20) == 0x20;
 733 }
 734
 735
 736 static int inf_mode_valid = 0;
 737 static int inf_terminal_mode;
 738
 739 /* This semaphore is needed because, amazingly enough, GDB calls
 740    target.to_terminal_ours more than once after the inferior stops.
 741    But we need the information from the first call only, since the
 742    second call will always see GDB's own cooked terminal.  */
 743 static int terminal_is_ours = 1;
 744
 745 static void
 746 go32_terminal_init (void)
 747 {
 748   inf_mode_valid = 0;   /* reinitialize, in case they are restarting child */
 749   terminal_is_ours = 1;
 750 }
 751
 752 static void
 753 go32_terminal_info (char *args, int from_tty)
 754 {
 755   printf_unfiltered ("Inferior's terminal is in %s mode.\n",
 756                      !inf_mode_valid
 757                      ? "default" : inf_terminal_mode ? "raw" : "cooked");
 758
 759 #if __DJGPP_MINOR__ > 2
 760   if (child_cmd.redirection)
 761   {
 762     int i;
 763
 764     for (i = 0; i < DBG_HANDLES; i++)
 765     {
 766       if (child_cmd.redirection[i]->file_name)
 767         printf_unfiltered ("\tFile handle %d is redirected to `%s'.\n",
 768                            i, child_cmd.redirection[i]->file_name);
 769       else if (_get_dev_info (child_cmd.redirection[i]->inf_handle) == -1)
 770         printf_unfiltered
 771           ("\tFile handle %d appears to be closed by inferior.\n", i);
 772       /* Mask off the raw/cooked bit when comparing device info words.  */
 773       else if ((_get_dev_info (child_cmd.redirection[i]->inf_handle) & 0xdf)
 774                != (_get_dev_info (i) & 0xdf))
 775         printf_unfiltered
 776           ("\tFile handle %d appears to be redirected by inferior.\n", i);
 777     }
 778   }
 779 #endif
 780 }
 781
 782 static void
 783 go32_terminal_inferior (void)
 784 {
 785   /* Redirect standard handles as child wants them.  */
 786   errno = 0;
 787   if (redir_to_child (&child_cmd) == -1)
 788   {
 789     redir_to_debugger (&child_cmd);
 790     error ("Cannot redirect standard handles for program: %s.",
 791            strerror (errno));
 792   }
 793   /* set the console device of the inferior to whatever mode
 794      (raw or cooked) we found it last time */
 795   if (terminal_is_ours)
 796   {
 797     if (inf_mode_valid)
 798       device_mode (0, inf_terminal_mode);
 799     terminal_is_ours = 0;
 800   }
 801 }
 802
 803 static void
 804 go32_terminal_ours (void)
 805 {
 806   /* Switch to cooked mode on the gdb terminal and save the inferior
 807      terminal mode to be restored when it is resumed */
 808   if (!terminal_is_ours)
 809   {
 810     inf_terminal_mode = device_mode (0, 0);
 811     if (inf_terminal_mode != -1)
 812       inf_mode_valid = 1;
 813     else
 814       /* If device_mode returned -1, we don't know what happens with
 815          handle 0 anymore, so make the info invalid.  */
 816       inf_mode_valid = 0;
 817     terminal_is_ours = 1;
 818
 819     /* Restore debugger's standard handles.  */
 820     errno = 0;
 821     if (redir_to_debugger (&child_cmd) == -1)
 822     {
 823       redir_to_child (&child_cmd);
 824       error ("Cannot redirect standard handles for debugger: %s.",
 825              strerror (errno));
 826     }
 827   }
 828 }
 829
 830 static void
 831 init_go32_ops (void)
 832 {
 833   go32_ops.to_shortname = "djgpp";
 834   go32_ops.to_longname = "djgpp target process";
 835   go32_ops.to_doc =
 836     "Program loaded by djgpp, when gdb is used as an external debugger";
 837   go32_ops.to_open = go32_open;
 838   go32_ops.to_close = go32_close;
 839   go32_ops.to_attach = go32_attach;
 840   go32_ops.to_detach = go32_detach;
 841   go32_ops.to_resume = go32_resume;
 842   go32_ops.to_wait = go32_wait;
 843   go32_ops.to_fetch_registers = go32_fetch_registers;
 844   go32_ops.to_store_registers = go32_store_registers;
 845   go32_ops.to_prepare_to_store = go32_prepare_to_store;
 846   go32_ops.to_xfer_memory = go32_xfer_memory;
 847   go32_ops.to_files_info = go32_files_info;
 848   go32_ops.to_insert_breakpoint = memory_insert_breakpoint;
 849   go32_ops.to_remove_breakpoint = memory_remove_breakpoint;
 850   go32_ops.to_terminal_init = go32_terminal_init;
 851   go32_ops.to_terminal_inferior = go32_terminal_inferior;
 852   go32_ops.to_terminal_ours_for_output = go32_terminal_ours;
 853   go32_ops.to_terminal_ours = go32_terminal_ours;
 854   go32_ops.to_terminal_info = go32_terminal_info;
 855   go32_ops.to_kill = go32_kill_inferior;
 856   go32_ops.to_create_inferior = go32_create_inferior;
 857   go32_ops.to_mourn_inferior = go32_mourn_inferior;
 858   go32_ops.to_can_run = go32_can_run;
 859   go32_ops.to_stop = go32_stop;
 860   go32_ops.to_stratum = process_stratum;
 861   go32_ops.to_has_all_memory = 1;
 862   go32_ops.to_has_memory = 1;
 863   go32_ops.to_has_stack = 1;
 864   go32_ops.to_has_registers = 1;
 865   go32_ops.to_has_execution = 1;
 866   go32_ops.to_magic = OPS_MAGIC;
 867
 868   /* Initialize child's cwd as empty to be initialized when starting
 869      the child.  */
 870   *child_cwd = 0;
 871
 872   /* Initialize child's command line storage.  */
 873   if (redir_debug_init (&child_cmd) == -1)
 874     internal_error (__FILE__, __LINE__,
 875                     "Cannot allocate redirection storage: not enough memory.\n");
 876
 877   /* We are always processing GCC-compiled programs.  */
 878   processing_gcc_compilation = 2;
 879 }
 880
 881 void
 882 _initialize_go32_nat (void)
 883 {
 884   init_go32_ops ();
 885   add_target (&go32_ops);
 886 }
 887
 888 pid_t
 889 tcgetpgrp (int fd)
 890 {
 891   if (isatty (fd))
 892     return SOME_PID;
 893   errno = ENOTTY;
 894   return -1;
 895 }
 896
 897 int
 898 tcsetpgrp (int fd, pid_t pgid)
 899 {
 900   if (isatty (fd) && pgid == SOME_PID)
 901     return 0;
 902   errno = pgid == SOME_PID ? ENOTTY : ENOSYS;
 903   return -1;
 904 }