-/* Native dependent code for dos running GO32 for GDB, the GNU debugger.
- Copyright 1992 Free Software Foundation, Inc.
+/* Native debugging support for Intel x86 running DJGPP.
+ Copyright (C) 1997-2020 Free Software Foundation, Inc.
+ Written by Robert Hoehne.
-This file is part of GDB.
+ This file is part of GDB.
-This program is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2 of the License, or
-(at your option) any later version.
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
-You should have received a copy of the GNU General Public License
-along with this program; if not, write to the Free Software
-Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
-#include <stdio.h>
+/* To whomever it may concern, here's a general description of how
+ debugging in DJGPP works, and the special quirks GDB does to
+ support that.
-static void uerror(char *s)
+ When the DJGPP port of GDB is debugging a DJGPP program natively,
+ there aren't 2 separate processes, the debuggee and GDB itself, as
+ on other systems. (This is DOS, where there can only be one active
+ process at any given time, remember?) Instead, GDB and the
+ debuggee live in the same process. So when GDB calls
+ go32_create_inferior below, and that function calls edi_init from
+ the DJGPP debug support library libdbg.a, we load the debuggee's
+ executable file into GDB's address space, set it up for execution
+ as the stub loader (a short real-mode program prepended to each
+ DJGPP executable) normally would, and do a lot of preparations for
+ swapping between GDB's and debuggee's internal state, primarily wrt
+ the exception handlers. This swapping happens every time we resume
+ the debuggee or switch back to GDB's code, and it includes:
+
+ . swapping all the segment registers
+ . swapping the PSP (the Program Segment Prefix)
+ . swapping the signal handlers
+ . swapping the exception handlers
+ . swapping the FPU status
+ . swapping the 3 standard file handles (more about this below)
+
+ Then running the debuggee simply means longjmp into it where its PC
+ is and let it run until it stops for some reason. When it stops,
+ GDB catches the exception that stopped it and longjmp's back into
+ its own code. All the possible exit points of the debuggee are
+ watched; for example, the normal exit point is recognized because a
+ DOS program issues a special system call to exit. If one of those
+ exit points is hit, we mourn the inferior and clean up after it.
+ Cleaning up is very important, even if the process exits normally,
+ because otherwise we might leave behind traces of previous
+ execution, and in several cases GDB itself might be left hosed,
+ because all the exception handlers were not restored.
+
+ Swapping of the standard handles (in redir_to_child and
+ redir_to_debugger) is needed because, since both GDB and the
+ debuggee live in the same process, as far as the OS is concerned,
+ the share the same file table. This means that the standard
+ handles 0, 1, and 2 point to the same file table entries, and thus
+ are connected to the same devices. Therefore, if the debugger
+ redirects its standard output, the standard output of the debuggee
+ is also automagically redirected to the same file/device!
+ Similarly, if the debuggee redirects its stdout to a file, you
+ won't be able to see debugger's output (it will go to the same file
+ where the debuggee has its output); and if the debuggee closes its
+ standard input, you will lose the ability to talk to debugger!
+
+ For this reason, every time the debuggee is about to be resumed, we
+ call redir_to_child, which redirects the standard handles to where
+ the debuggee expects them to be. When the debuggee stops and GDB
+ regains control, we call redir_to_debugger, which redirects those 3
+ handles back to where GDB expects.
+
+ Note that only the first 3 handles are swapped, so if the debuggee
+ redirects or closes any other handles, GDB will not notice. In
+ particular, the exit code of a DJGPP program forcibly closes all
+ file handles beyond the first 3 ones, so when the debuggee exits,
+ GDB currently loses its stdaux and stdprn streams. Fortunately,
+ GDB does not use those as of this writing, and will never need
+ to. */
+
+#include "defs.h"
+
+#include <fcntl.h>
+
+#include "x86-nat.h"
+#include "inferior.h"
+#include "infrun.h"
+#include "gdbthread.h"
+#include "gdbsupport/gdb_wait.h"
+#include "gdbcore.h"
+#include "command.h"
+#include "gdbcmd.h"
+#include "floatformat.h"
+#include "buildsym-legacy.h"
+#include "i387-tdep.h"
+#include "i386-tdep.h"
+#include "nat/x86-cpuid.h"
+#include "value.h"
+#include "regcache.h"
+#include "top.h"
+#include "cli/cli-utils.h"
+#include "inf-child.h"
+
+#include <ctype.h>
+#include <unistd.h>
+#include <sys/utsname.h>
+#include <io.h>
+#include <dos.h>
+#include <dpmi.h>
+#include <go32.h>
+#include <sys/farptr.h>
+#include <debug/v2load.h>
+#include <debug/dbgcom.h>
+#if __DJGPP_MINOR__ > 2
+#include <debug/redir.h>
+#endif
+
+#include <langinfo.h>
+
+#if __DJGPP_MINOR__ < 3
+/* This code will be provided from DJGPP 2.03 on. Until then I code it
+ here. */
+typedef struct
+ {
+ unsigned short sig0;
+ unsigned short sig1;
+ unsigned short sig2;
+ unsigned short sig3;
+ unsigned short exponent:15;
+ unsigned short sign:1;
+ }
+NPXREG;
+
+typedef struct
+ {
+ unsigned int control;
+ unsigned int status;
+ unsigned int tag;
+ unsigned int eip;
+ unsigned int cs;
+ unsigned int dataptr;
+ unsigned int datasel;
+ NPXREG reg[8];
+ }
+NPX;
+
+static NPX npx;
+
+static void save_npx (void); /* Save the FPU of the debugged program. */
+static void load_npx (void); /* Restore the FPU of the debugged program. */
+
+/* ------------------------------------------------------------------------- */
+/* Store the contents of the NPX in the global variable `npx'. */
+/* *INDENT-OFF* */
+
+static void
+save_npx (void)
+{
+ asm ("inb $0xa0, %%al \n\
+ testb $0x20, %%al \n\
+ jz 1f \n\
+ xorb %%al, %%al \n\
+ outb %%al, $0xf0 \n\
+ movb $0x20, %%al \n\
+ outb %%al, $0xa0 \n\
+ outb %%al, $0x20 \n\
+1: \n\
+ fnsave %0 \n\
+ fwait "
+: "=m" (npx)
+: /* No input */
+: "%eax");
+}
+
+/* *INDENT-ON* */
+
+
+/* ------------------------------------------------------------------------- */
+/* Reload the contents of the NPX from the global variable `npx'. */
+
+static void
+load_npx (void)
+{
+ asm ("frstor %0":"=m" (npx));
+}
+/* ------------------------------------------------------------------------- */
+/* Stubs for the missing redirection functions. */
+typedef struct {
+ char *command;
+ int redirected;
+} cmdline_t;
+
+void
+redir_cmdline_delete (cmdline_t *ptr)
+{
+ ptr->redirected = 0;
+}
+
+int
+redir_cmdline_parse (const char *args, cmdline_t *ptr)
+{
+ return -1;
+}
+
+int
+redir_to_child (cmdline_t *ptr)
+{
+ return 1;
+}
+
+int
+redir_to_debugger (cmdline_t *ptr)
+{
+ return 1;
+}
+
+int
+redir_debug_init (cmdline_t *ptr)
+{
+ return 0;
+}
+#endif /* __DJGPP_MINOR < 3 */
+
+typedef enum { wp_insert, wp_remove, wp_count } wp_op;
+
+/* This holds the current reference counts for each debug register. */
+static int dr_ref_count[4];
+
+#define SOME_PID 42
+
+static int prog_has_started = 0;
+
+#define r_ofs(x) (offsetof(TSS,x))
+
+static struct
+{
+ size_t tss_ofs;
+ size_t size;
+}
+regno_mapping[] =
+{
+ {r_ofs (tss_eax), 4}, /* normal registers, from a_tss */
+ {r_ofs (tss_ecx), 4},
+ {r_ofs (tss_edx), 4},
+ {r_ofs (tss_ebx), 4},
+ {r_ofs (tss_esp), 4},
+ {r_ofs (tss_ebp), 4},
+ {r_ofs (tss_esi), 4},
+ {r_ofs (tss_edi), 4},
+ {r_ofs (tss_eip), 4},
+ {r_ofs (tss_eflags), 4},
+ {r_ofs (tss_cs), 2},
+ {r_ofs (tss_ss), 2},
+ {r_ofs (tss_ds), 2},
+ {r_ofs (tss_es), 2},
+ {r_ofs (tss_fs), 2},
+ {r_ofs (tss_gs), 2},
+ {0, 10}, /* 8 FP registers, from npx.reg[] */
+ {1, 10},
+ {2, 10},
+ {3, 10},
+ {4, 10},
+ {5, 10},
+ {6, 10},
+ {7, 10},
+ /* The order of the next 7 registers must be consistent
+ with their numbering in config/i386/tm-i386.h, which see. */
+ {0, 2}, /* control word, from npx */
+ {4, 2}, /* status word, from npx */
+ {8, 2}, /* tag word, from npx */
+ {16, 2}, /* last FP exception CS from npx */
+ {12, 4}, /* last FP exception EIP from npx */
+ {24, 2}, /* last FP exception operand selector from npx */
+ {20, 4}, /* last FP exception operand offset from npx */
+ {18, 2} /* last FP opcode from npx */
+};
+
+static struct
+ {
+ int go32_sig;
+ enum gdb_signal gdb_sig;
+ }
+sig_map[] =
+{
+ {0, GDB_SIGNAL_FPE},
+ {1, GDB_SIGNAL_TRAP},
+ /* Exception 2 is triggered by the NMI. DJGPP handles it as SIGILL,
+ but I think SIGBUS is better, since the NMI is usually activated
+ as a result of a memory parity check failure. */
+ {2, GDB_SIGNAL_BUS},
+ {3, GDB_SIGNAL_TRAP},
+ {4, GDB_SIGNAL_FPE},
+ {5, GDB_SIGNAL_SEGV},
+ {6, GDB_SIGNAL_ILL},
+ {7, GDB_SIGNAL_EMT}, /* no-coprocessor exception */
+ {8, GDB_SIGNAL_SEGV},
+ {9, GDB_SIGNAL_SEGV},
+ {10, GDB_SIGNAL_BUS},
+ {11, GDB_SIGNAL_SEGV},
+ {12, GDB_SIGNAL_SEGV},
+ {13, GDB_SIGNAL_SEGV},
+ {14, GDB_SIGNAL_SEGV},
+ {16, GDB_SIGNAL_FPE},
+ {17, GDB_SIGNAL_BUS},
+ {31, GDB_SIGNAL_ILL},
+ {0x1b, GDB_SIGNAL_INT},
+ {0x75, GDB_SIGNAL_FPE},
+ {0x78, GDB_SIGNAL_ALRM},
+ {0x79, GDB_SIGNAL_INT},
+ {0x7a, GDB_SIGNAL_QUIT},
+ {-1, GDB_SIGNAL_LAST}
+};
+
+static struct {
+ enum gdb_signal gdb_sig;
+ int djgpp_excepno;
+} excepn_map[] = {
+ {GDB_SIGNAL_0, -1},
+ {GDB_SIGNAL_ILL, 6}, /* Invalid Opcode */
+ {GDB_SIGNAL_EMT, 7}, /* triggers SIGNOFP */
+ {GDB_SIGNAL_SEGV, 13}, /* GPF */
+ {GDB_SIGNAL_BUS, 17}, /* Alignment Check */
+ /* The rest are fake exceptions, see dpmiexcp.c in djlsr*.zip for
+ details. */
+ {GDB_SIGNAL_TERM, 0x1b}, /* triggers Ctrl-Break type of SIGINT */
+ {GDB_SIGNAL_FPE, 0x75},
+ {GDB_SIGNAL_INT, 0x79},
+ {GDB_SIGNAL_QUIT, 0x7a},
+ {GDB_SIGNAL_ALRM, 0x78}, /* triggers SIGTIMR */
+ {GDB_SIGNAL_PROF, 0x78},
+ {GDB_SIGNAL_LAST, -1}
+};
+
+/* The go32 target. */
+
+struct go32_nat_target final : public x86_nat_target<inf_child_target>
+{
+ void attach (const char *, int) override;
+
+ void resume (ptid_t, int, enum gdb_signal) override;
+
+ ptid_t wait (ptid_t, struct target_waitstatus *, int) override;
+
+ void fetch_registers (struct regcache *, int) override;
+ void store_registers (struct regcache *, int) override;
+
+ enum target_xfer_status xfer_partial (enum target_object object,
+ const char *annex,
+ gdb_byte *readbuf,
+ const gdb_byte *writebuf,
+ ULONGEST offset, ULONGEST len,
+ ULONGEST *xfered_len) override;
+
+ void files_info () override;
+
+ void terminal_init () override;
+
+ void terminal_inferior () override;
+
+ void terminal_ours_for_output () override;
+
+ void terminal_ours () override;
+
+ void terminal_info (const char *, int) override;
+
+ void pass_ctrlc () override;
+
+ void kill () override;
+
+ void create_inferior (const char *, const std::string &,
+ char **, int) override;
+
+ void mourn_inferior () override;
+
+ bool thread_alive (ptid_t ptid) override;
+
+ std::string pid_to_str (ptid_t) override;
+};
+
+static go32_nat_target the_go32_nat_target;
+
+void
+go32_nat_target::attach (const char *args, int from_tty)
+{
+ error (_("\
+You cannot attach to a running program on this platform.\n\
+Use the `run' command to run DJGPP programs."));
+}
+
+static int resume_is_step;
+static int resume_signal = -1;
+
+void
+go32_nat_target::resume (ptid_t ptid, int step, enum gdb_signal siggnal)
+{
+ int i;
+
+ resume_is_step = step;
+
+ if (siggnal != GDB_SIGNAL_0 && siggnal != GDB_SIGNAL_TRAP)
+ {
+ for (i = 0, resume_signal = -1;
+ excepn_map[i].gdb_sig != GDB_SIGNAL_LAST; i++)
+ if (excepn_map[i].gdb_sig == siggnal)
+ {
+ resume_signal = excepn_map[i].djgpp_excepno;
+ break;
+ }
+ if (resume_signal == -1)
+ printf_unfiltered ("Cannot deliver signal %s on this platform.\n",
+ gdb_signal_to_name (siggnal));
+ }
+}
+
+static char child_cwd[FILENAME_MAX];
+
+ptid_t
+go32_nat_target::wait (ptid_t ptid, struct target_waitstatus *status,
+ int options)
+{
+ int i;
+ unsigned char saved_opcode;
+ unsigned long INT3_addr = 0;
+ int stepping_over_INT = 0;
+
+ a_tss.tss_eflags &= 0xfeff; /* Reset the single-step flag (TF). */
+ if (resume_is_step)
+ {
+ /* If the next instruction is INT xx or INTO, we need to handle
+ them specially. Intel manuals say that these instructions
+ reset the single-step flag (a.k.a. TF). However, it seems
+ that, at least in the DPMI environment, and at least when
+ stepping over the DPMI interrupt 31h, the problem is having
+ TF set at all when INT 31h is executed: the debuggee either
+ crashes (and takes the system with it) or is killed by a
+ SIGTRAP.
+
+ So we need to emulate single-step mode: we put an INT3 opcode
+ right after the INT xx instruction, let the debuggee run
+ until it hits INT3 and stops, then restore the original
+ instruction which we overwrote with the INT3 opcode, and back
+ up the debuggee's EIP to that instruction. */
+ read_child (a_tss.tss_eip, &saved_opcode, 1);
+ if (saved_opcode == 0xCD || saved_opcode == 0xCE)
+ {
+ unsigned char INT3_opcode = 0xCC;
+
+ INT3_addr
+ = saved_opcode == 0xCD ? a_tss.tss_eip + 2 : a_tss.tss_eip + 1;
+ stepping_over_INT = 1;
+ read_child (INT3_addr, &saved_opcode, 1);
+ write_child (INT3_addr, &INT3_opcode, 1);
+ }
+ else
+ a_tss.tss_eflags |= 0x0100; /* normal instruction: set TF */
+ }
+
+ /* The special value FFFFh in tss_trap indicates to run_child that
+ tss_irqn holds a signal to be delivered to the debuggee. */
+ if (resume_signal <= -1)
+ {
+ a_tss.tss_trap = 0;
+ a_tss.tss_irqn = 0xff;
+ }
+ else
+ {
+ a_tss.tss_trap = 0xffff; /* run_child looks for this. */
+ a_tss.tss_irqn = resume_signal;
+ }
+
+ /* The child might change working directory behind our back. The
+ GDB users won't like the side effects of that when they work with
+ relative file names, and GDB might be confused by its current
+ directory not being in sync with the truth. So we always make a
+ point of changing back to where GDB thinks is its cwd, when we
+ return control to the debugger, but restore child's cwd before we
+ run it. */
+ /* Initialize child_cwd, before the first call to run_child and not
+ in the initialization, so the child get also the changed directory
+ set with the gdb-command "cd ..." */
+ if (!*child_cwd)
+ /* Initialize child's cwd with the current one. */
+ getcwd (child_cwd, sizeof (child_cwd));
+
+ chdir (child_cwd);
+
+#if __DJGPP_MINOR__ < 3
+ load_npx ();
+#endif
+ run_child ();
+#if __DJGPP_MINOR__ < 3
+ save_npx ();
+#endif
+
+ /* Did we step over an INT xx instruction? */
+ if (stepping_over_INT && a_tss.tss_eip == INT3_addr + 1)
+ {
+ /* Restore the original opcode. */
+ a_tss.tss_eip--; /* EIP points *after* the INT3 instruction. */
+ write_child (a_tss.tss_eip, &saved_opcode, 1);
+ /* Simulate a TRAP exception. */
+ a_tss.tss_irqn = 1;
+ a_tss.tss_eflags |= 0x0100;
+ }
+
+ getcwd (child_cwd, sizeof (child_cwd)); /* in case it has changed */
+ if (current_directory != NULL)
+ chdir (current_directory);
+
+ if (a_tss.tss_irqn == 0x21)
+ {
+ status->kind = TARGET_WAITKIND_EXITED;
+ status->value.integer = a_tss.tss_eax & 0xff;
+ }
+ else
+ {
+ status->value.sig = GDB_SIGNAL_UNKNOWN;
+ status->kind = TARGET_WAITKIND_STOPPED;
+ for (i = 0; sig_map[i].go32_sig != -1; i++)
+ {
+ if (a_tss.tss_irqn == sig_map[i].go32_sig)
+ {
+#if __DJGPP_MINOR__ < 3
+ if ((status->value.sig = sig_map[i].gdb_sig) !=
+ GDB_SIGNAL_TRAP)
+ status->kind = TARGET_WAITKIND_SIGNALLED;
+#else
+ status->value.sig = sig_map[i].gdb_sig;
+#endif
+ break;
+ }
+ }
+ }
+ return ptid_t (SOME_PID);
+}
+
+static void
+fetch_register (struct regcache *regcache, int regno)
+{
+ struct gdbarch *gdbarch = regcache->arch ();
+ if (regno < gdbarch_fp0_regnum (gdbarch))
+ regcache->raw_supply (regno,
+ (char *) &a_tss + regno_mapping[regno].tss_ofs);
+ else if (i386_fp_regnum_p (gdbarch, regno) || i386_fpc_regnum_p (gdbarch,
+ regno))
+ i387_supply_fsave (regcache, regno, &npx);
+ else
+ internal_error (__FILE__, __LINE__,
+ _("Invalid register no. %d in fetch_register."), regno);
+}
+
+void
+go32_nat_target::fetch_registers (struct regcache *regcache, int regno)
+{
+ if (regno >= 0)
+ fetch_register (regcache, regno);
+ else
+ {
+ for (regno = 0;
+ regno < gdbarch_fp0_regnum (regcache->arch ());
+ regno++)
+ fetch_register (regcache, regno);
+ i387_supply_fsave (regcache, -1, &npx);
+ }
+}
+
+static void
+store_register (const struct regcache *regcache, int regno)
+{
+ struct gdbarch *gdbarch = regcache->arch ();
+ if (regno < gdbarch_fp0_regnum (gdbarch))
+ regcache->raw_collect (regno,
+ (char *) &a_tss + regno_mapping[regno].tss_ofs);
+ else if (i386_fp_regnum_p (gdbarch, regno) || i386_fpc_regnum_p (gdbarch,
+ regno))
+ i387_collect_fsave (regcache, regno, &npx);
+ else
+ internal_error (__FILE__, __LINE__,
+ _("Invalid register no. %d in store_register."), regno);
+}
+
+void
+go32_nat_target::store_registers (struct regcache *regcache, int regno)
+{
+ unsigned r;
+
+ if (regno >= 0)
+ store_register (regcache, regno);
+ else
+ {
+ for (r = 0; r < gdbarch_fp0_regnum (regcache->arch ()); r++)
+ store_register (regcache, r);
+ i387_collect_fsave (regcache, -1, &npx);
+ }
+}
+
+/* Const-correct version of DJGPP's write_child, which unfortunately
+ takes a non-const buffer pointer. */
+
+static int
+my_write_child (unsigned child_addr, const void *buf, unsigned len)
+{
+ static void *buffer = NULL;
+ static unsigned buffer_len = 0;
+ int res;
+
+ if (buffer_len < len)
+ {
+ buffer = xrealloc (buffer, len);
+ buffer_len = len;
+ }
+
+ memcpy (buffer, buf, len);
+ res = write_child (child_addr, buffer, len);
+ return res;
+}
+
+/* Helper for go32_xfer_partial that handles memory transfers.
+ Arguments are like target_xfer_partial. */
+
+static enum target_xfer_status
+go32_xfer_memory (gdb_byte *readbuf, const gdb_byte *writebuf,
+ ULONGEST memaddr, ULONGEST len, ULONGEST *xfered_len)
+{
+ int res;
+
+ if (writebuf != NULL)
+ res = my_write_child (memaddr, writebuf, len);
+ else
+ res = read_child (memaddr, readbuf, len);
+
+ /* read_child and write_child return zero on success, non-zero on
+ failure. */
+ if (res != 0)
+ return TARGET_XFER_E_IO;
+
+ *xfered_len = len;
+ return TARGET_XFER_OK;
+}
+
+/* Target to_xfer_partial implementation. */
+
+enum target_xfer_status
+go32_nat_target::xfer_partial (enum target_object object,
+ const char *annex, gdb_byte *readbuf,
+ const gdb_byte *writebuf, ULONGEST offset,
+ ULONGEST len,
+ ULONGEST *xfered_len)
+{
+ switch (object)
+ {
+ case TARGET_OBJECT_MEMORY:
+ return go32_xfer_memory (readbuf, writebuf, offset, len, xfered_len);
+
+ default:
+ return this->beneath ()->xfer_partial (object, annex,
+ readbuf, writebuf, offset, len,
+ xfered_len);
+ }
+}
+
+static cmdline_t child_cmd; /* Parsed child's command line kept here. */
+
+void
+go32_nat_target::files_info ()
+{
+ printf_unfiltered ("You are running a DJGPP V2 program.\n");
+}
+
+void
+go32_nat_target::kill_inferior ()
+{
+ mourn_inferior ();
+}
+
+void
+go32_nat_target::create_inferior (const char *exec_file,
+ const std::string &allargs,
+ char **env, int from_tty)
+{
+ extern char **environ;
+ jmp_buf start_state;
+ char *cmdline;
+ char **env_save = environ;
+ size_t cmdlen;
+ struct inferior *inf;
+ int result;
+ const char *args = allargs.c_str ();
+
+ /* If no exec file handed to us, get it from the exec-file command -- with
+ a good, common error message if none is specified. */
+ if (exec_file == 0)
+ exec_file = get_exec_file (1);
+
+ resume_signal = -1;
+ resume_is_step = 0;
+
+ /* Initialize child's cwd as empty to be initialized when starting
+ the child. */
+ *child_cwd = 0;
+
+ /* Init command line storage. */
+ if (redir_debug_init (&child_cmd) == -1)
+ internal_error (__FILE__, __LINE__,
+ _("Cannot allocate redirection storage: "
+ "not enough memory.\n"));
+
+ /* Parse the command line and create redirections. */
+ if (strpbrk (args, "<>"))
+ {
+ if (redir_cmdline_parse (args, &child_cmd) == 0)
+ args = child_cmd.command;
+ else
+ error (_("Syntax error in command line."));
+ }
+ else
+ child_cmd.command = xstrdup (args);
+
+ cmdlen = strlen (args);
+ /* v2loadimage passes command lines via DOS memory, so it cannot
+ possibly handle commands longer than 1MB. */
+ if (cmdlen > 1024*1024)
+ error (_("Command line too long."));
+
+ cmdline = (char *) xmalloc (cmdlen + 4);
+ strcpy (cmdline + 1, args);
+ /* If the command-line length fits into DOS 126-char limits, use the
+ DOS command tail format; otherwise, tell v2loadimage to pass it
+ through a buffer in conventional memory. */
+ if (cmdlen < 127)
+ {
+ cmdline[0] = strlen (args);
+ cmdline[cmdlen + 1] = 13;
+ }
+ else
+ cmdline[0] = 0xff; /* Signal v2loadimage it's a long command. */
+
+ environ = env;
+
+ result = v2loadimage (exec_file, cmdline, start_state);
+
+ environ = env_save;
+ xfree (cmdline);
+
+ if (result != 0)
+ error (_("Load failed for image %s"), exec_file);
+
+ edi_init (start_state);
+#if __DJGPP_MINOR__ < 3
+ save_npx ();
+#endif
+
+ inferior_ptid = ptid_t (SOME_PID);
+ inf = current_inferior ();
+ inferior_appeared (inf, SOME_PID);
+
+ if (!target_is_pushed (this))
+ push_target (this);
+
+ add_thread_silent (inferior_ptid);
+
+ clear_proceed_status (0);
+ insert_breakpoints ();
+ prog_has_started = 1;
+}
+
+void
+go32_nat_target::mourn_inferior ()
+{
+ ptid_t ptid;
+
+ redir_cmdline_delete (&child_cmd);
+ resume_signal = -1;
+ resume_is_step = 0;
+
+ cleanup_client ();
+
+ /* We need to make sure all the breakpoint enable bits in the DR7
+ register are reset when the inferior exits. Otherwise, if they
+ rerun the inferior, the uncleared bits may cause random SIGTRAPs,
+ failure to set more watchpoints, and other calamities. It would
+ be nice if GDB itself would take care to remove all breakpoints
+ at all times, but it doesn't, probably under an assumption that
+ the OS cleans up when the debuggee exits. */
+ x86_cleanup_dregs ();
+
+ ptid = inferior_ptid;
+ inferior_ptid = null_ptid;
+ prog_has_started = 0;
+
+ generic_mourn_inferior ();
+ maybe_unpush_target ();
+}
+
+/* Hardware watchpoint support. */
+
+#define D_REGS edi.dr
+#define CONTROL D_REGS[7]
+#define STATUS D_REGS[6]
+
+/* Pass the address ADDR to the inferior in the I'th debug register.
+ Here we just store the address in D_REGS, the watchpoint will be
+ actually set up when go32_wait runs the debuggee. */
+static void
+go32_set_dr (int i, CORE_ADDR addr)
+{
+ if (i < 0 || i > 3)
+ internal_error (__FILE__, __LINE__,
+ _("Invalid register %d in go32_set_dr.\n"), i);
+ D_REGS[i] = addr;
+}
+
+/* Pass the value VAL to the inferior in the DR7 debug control
+ register. Here we just store the address in D_REGS, the watchpoint
+ will be actually set up when go32_wait runs the debuggee. */
+static void
+go32_set_dr7 (unsigned long val)
{
- fprintf(stderr, "Fatal: %s!\n");
- exit(1);
+ CONTROL = val;
}
-fetch_core_registers(){uerror("attempt to call fetch_core_registers()");}
+/* Get the value of the DR6 debug status register from the inferior.
+ Here we just return the value stored in D_REGS, as we've got it
+ from the last go32_wait call. */
+static unsigned long
+go32_get_dr6 (void)
+{
+ return STATUS;
+}
+
+/* Get the value of the DR7 debug status register from the inferior.
+ Here we just return the value stored in D_REGS, as we've got it
+ from the last go32_wait call. */
+
+static unsigned long
+go32_get_dr7 (void)
+{
+ return CONTROL;
+}
-fetch_inferior_registers(){uerror("attempt to call fetch_inferior_registers()");}
-store_inferior_registers(){uerror("attempt to call store_inferior_registers()");}
+/* Get the value of the DR debug register I from the inferior. Here
+ we just return the value stored in D_REGS, as we've got it from the
+ last go32_wait call. */
-child_resume(){uerror("attempt to call child_resume()");}
-child_xfer_memory(){uerror("attempt to call child_xfer_memory()");}
+static CORE_ADDR
+go32_get_dr (int i)
+{
+ if (i < 0 || i > 3)
+ internal_error (__FILE__, __LINE__,
+ _("Invalid register %d in go32_get_dr.\n"), i);
+ return D_REGS[i];
+}
+
+/* Put the device open on handle FD into either raw or cooked
+ mode, return 1 if it was in raw mode, zero otherwise. */
+
+static int
+device_mode (int fd, int raw_p)
+{
+ int oldmode, newmode;
+ __dpmi_regs regs;
+ regs.x.ax = 0x4400;
+ regs.x.bx = fd;
+ __dpmi_int (0x21, ®s);
+ if (regs.x.flags & 1)
+ return -1;
+ newmode = oldmode = regs.x.dx;
+
+ if (raw_p)
+ newmode |= 0x20;
+ else
+ newmode &= ~0x20;
+
+ if (oldmode & 0x80) /* Only for character dev. */
+ {
+ regs.x.ax = 0x4401;
+ regs.x.bx = fd;
+ regs.x.dx = newmode & 0xff; /* Force upper byte zero, else it fails. */
+ __dpmi_int (0x21, ®s);
+ if (regs.x.flags & 1)
+ return -1;
+ }
+ return (oldmode & 0x20) == 0x20;
+}
+
+
+static int inf_mode_valid = 0;
+static int inf_terminal_mode;
+
+/* This semaphore is needed because, amazingly enough, GDB calls
+ target.to_terminal_ours more than once after the inferior stops.
+ But we need the information from the first call only, since the
+ second call will always see GDB's own cooked terminal. */
+static int terminal_is_ours = 1;
+
+void
+go32_nat_target::terminal_init ()
+{
+ inf_mode_valid = 0; /* Reinitialize, in case they are restarting child. */
+ terminal_is_ours = 1;
+}
+
+void
+go32_nat_target::terminal_info (const char *args, int from_tty)
+{
+ printf_unfiltered ("Inferior's terminal is in %s mode.\n",
+ !inf_mode_valid
+ ? "default" : inf_terminal_mode ? "raw" : "cooked");
+
+#if __DJGPP_MINOR__ > 2
+ if (child_cmd.redirection)
+ {
+ int i;
+
+ for (i = 0; i < DBG_HANDLES; i++)
+ {
+ if (child_cmd.redirection[i]->file_name)
+ printf_unfiltered ("\tFile handle %d is redirected to `%s'.\n",
+ i, child_cmd.redirection[i]->file_name);
+ else if (_get_dev_info (child_cmd.redirection[i]->inf_handle) == -1)
+ printf_unfiltered
+ ("\tFile handle %d appears to be closed by inferior.\n", i);
+ /* Mask off the raw/cooked bit when comparing device info words. */
+ else if ((_get_dev_info (child_cmd.redirection[i]->inf_handle) & 0xdf)
+ != (_get_dev_info (i) & 0xdf))
+ printf_unfiltered
+ ("\tFile handle %d appears to be redirected by inferior.\n", i);
+ }
+ }
+#endif
+}
+
+void
+go32_nat_target::terminal_inferior ()
+{
+ /* Redirect standard handles as child wants them. */
+ errno = 0;
+ if (redir_to_child (&child_cmd) == -1)
+ {
+ redir_to_debugger (&child_cmd);
+ error (_("Cannot redirect standard handles for program: %s."),
+ safe_strerror (errno));
+ }
+ /* Set the console device of the inferior to whatever mode
+ (raw or cooked) we found it last time. */
+ if (terminal_is_ours)
+ {
+ if (inf_mode_valid)
+ device_mode (0, inf_terminal_mode);
+ terminal_is_ours = 0;
+ }
+}
+
+void
+go32_nat_target::terminal_ours ()
+{
+ /* Switch to cooked mode on the gdb terminal and save the inferior
+ terminal mode to be restored when it is resumed. */
+ if (!terminal_is_ours)
+ {
+ inf_terminal_mode = device_mode (0, 0);
+ if (inf_terminal_mode != -1)
+ inf_mode_valid = 1;
+ else
+ /* If device_mode returned -1, we don't know what happens with
+ handle 0 anymore, so make the info invalid. */
+ inf_mode_valid = 0;
+ terminal_is_ours = 1;
+
+ /* Restore debugger's standard handles. */
+ errno = 0;
+ if (redir_to_debugger (&child_cmd) == -1)
+ {
+ redir_to_child (&child_cmd);
+ error (_("Cannot redirect standard handles for debugger: %s."),
+ safe_strerror (errno));
+ }
+ }
+}
+
+void
+go32_nat_target::pass_ctrlc ()
+{
+}
+
+bool
+go32_nat_target::thread_alive (ptid_t ptid)
+{
+ return ptid != null_ptid;
+}
+
+std::string
+go32_nat_target::pid_to_str (ptid_t ptid)
+{
+ return normal_pid_to_str (ptid);
+}
+
+/* Return the current DOS codepage number. */
+static int
+dos_codepage (void)
+{
+ __dpmi_regs regs;
+
+ regs.x.ax = 0x6601;
+ __dpmi_int (0x21, ®s);
+ if (!(regs.x.flags & 1))
+ return regs.x.bx & 0xffff;
+ else
+ return 437; /* default */
+}
+
+/* Limited emulation of `nl_langinfo', for charset.c. */
+char *
+nl_langinfo (nl_item item)
+{
+ char *retval;
+
+ switch (item)
+ {
+ case CODESET:
+ {
+ /* 8 is enough for SHORT_MAX + "CP" + null. */
+ char buf[8];
+ int blen = sizeof (buf);
+ int needed = snprintf (buf, blen, "CP%d", dos_codepage ());
+
+ if (needed > blen) /* Should never happen. */
+ buf[0] = 0;
+ retval = xstrdup (buf);
+ }
+ break;
+ default:
+ retval = xstrdup ("");
+ break;
+ }
+ return retval;
+}
+
+unsigned short windows_major, windows_minor;
+
+/* Compute the version Windows reports via Int 2Fh/AX=1600h. */
+static void
+go32_get_windows_version(void)
+{
+ __dpmi_regs r;
+
+ r.x.ax = 0x1600;
+ __dpmi_int(0x2f, &r);
+ if (r.h.al > 2 && r.h.al != 0x80 && r.h.al != 0xff
+ && (r.h.al > 3 || r.h.ah > 0))
+ {
+ windows_major = r.h.al;
+ windows_minor = r.h.ah;
+ }
+ else
+ windows_major = 0xff; /* meaning no Windows */
+}
+
+/* A subroutine of go32_sysinfo to display memory info. */
+static void
+print_mem (unsigned long datum, const char *header, int in_pages_p)
+{
+ if (datum != 0xffffffffUL)
+ {
+ if (in_pages_p)
+ datum <<= 12;
+ puts_filtered (header);
+ if (datum > 1024)
+ {
+ printf_filtered ("%lu KB", datum >> 10);
+ if (datum > 1024 * 1024)
+ printf_filtered (" (%lu MB)", datum >> 20);
+ }
+ else
+ printf_filtered ("%lu Bytes", datum);
+ puts_filtered ("\n");
+ }
+}
+
+/* Display assorted information about the underlying OS. */
+static void
+go32_sysinfo (const char *arg, int from_tty)
+{
+ static const char test_pattern[] =
+ "deadbeafdeadbeafdeadbeafdeadbeafdeadbeaf"
+ "deadbeafdeadbeafdeadbeafdeadbeafdeadbeaf"
+ "deadbeafdeadbeafdeadbeafdeadbeafdeadbeafdeadbeaf";
+ struct utsname u;
+ char cpuid_vendor[13];
+ unsigned cpuid_max = 0, cpuid_eax, cpuid_ebx, cpuid_ecx, cpuid_edx;
+ unsigned true_dos_version = _get_dos_version (1);
+ unsigned advertized_dos_version = ((unsigned int)_osmajor << 8) | _osminor;
+ int dpmi_flags;
+ char dpmi_vendor_info[129];
+ int dpmi_vendor_available;
+ __dpmi_version_ret dpmi_version_data;
+ long eflags;
+ __dpmi_free_mem_info mem_info;
+ __dpmi_regs regs;
+
+ cpuid_vendor[0] = '\0';
+ if (uname (&u))
+ strcpy (u.machine, "Unknown x86");
+ else if (u.machine[0] == 'i' && u.machine[1] > 4)
+ {
+ /* CPUID with EAX = 0 returns the Vendor ID. */
+#if 0
+ /* Ideally we would use x86_cpuid(), but it needs someone to run
+ native tests first to make sure things actually work. They should.
+ http://sourceware.org/ml/gdb-patches/2013-05/msg00164.html */
+ unsigned int eax, ebx, ecx, edx;
+
+ if (x86_cpuid (0, &eax, &ebx, &ecx, &edx))
+ {
+ cpuid_max = eax;
+ memcpy (&vendor[0], &ebx, 4);
+ memcpy (&vendor[4], &ecx, 4);
+ memcpy (&vendor[8], &edx, 4);
+ cpuid_vendor[12] = '\0';
+ }
+#else
+ __asm__ __volatile__ ("xorl %%ebx, %%ebx;"
+ "xorl %%ecx, %%ecx;"
+ "xorl %%edx, %%edx;"
+ "movl $0, %%eax;"
+ "cpuid;"
+ "movl %%ebx, %0;"
+ "movl %%edx, %1;"
+ "movl %%ecx, %2;"
+ "movl %%eax, %3;"
+ : "=m" (cpuid_vendor[0]),
+ "=m" (cpuid_vendor[4]),
+ "=m" (cpuid_vendor[8]),
+ "=m" (cpuid_max)
+ :
+ : "%eax", "%ebx", "%ecx", "%edx");
+ cpuid_vendor[12] = '\0';
+#endif
+ }
+
+ printf_filtered ("CPU Type.......................%s", u.machine);
+ if (cpuid_vendor[0])
+ printf_filtered (" (%s)", cpuid_vendor);
+ puts_filtered ("\n");
+
+ /* CPUID with EAX = 1 returns processor signature and features. */
+ if (cpuid_max >= 1)
+ {
+ static const char *brand_name[] = {
+ "",
+ " Celeron",
+ " III",
+ " III Xeon",
+ "", "", "", "",
+ " 4"
+ };
+ char cpu_string[80];
+ char cpu_brand[20];
+ unsigned brand_idx;
+ int intel_p = strcmp (cpuid_vendor, "GenuineIntel") == 0;
+ int amd_p = strcmp (cpuid_vendor, "AuthenticAMD") == 0;
+ int hygon_p = strcmp (cpuid_vendor, "HygonGenuine") == 0;
+ unsigned cpu_family, cpu_model;
+
+#if 0
+ /* See comment above about cpuid usage. */
+ x86_cpuid (1, &cpuid_eax, &cpuid_ebx, NULL, &cpuid_edx);
+#else
+ __asm__ __volatile__ ("movl $1, %%eax;"
+ "cpuid;"
+ : "=a" (cpuid_eax),
+ "=b" (cpuid_ebx),
+ "=d" (cpuid_edx)
+ :
+ : "%ecx");
+#endif
+ brand_idx = cpuid_ebx & 0xff;
+ cpu_family = (cpuid_eax >> 8) & 0xf;
+ cpu_model = (cpuid_eax >> 4) & 0xf;
+ cpu_brand[0] = '\0';
+ if (intel_p)
+ {
+ if (brand_idx > 0
+ && brand_idx < sizeof(brand_name)/sizeof(brand_name[0])
+ && *brand_name[brand_idx])
+ strcpy (cpu_brand, brand_name[brand_idx]);
+ else if (cpu_family == 5)
+ {
+ if (((cpuid_eax >> 12) & 3) == 0 && cpu_model == 4)
+ strcpy (cpu_brand, " MMX");
+ else if (cpu_model > 1 && ((cpuid_eax >> 12) & 3) == 1)
+ strcpy (cpu_brand, " OverDrive");
+ else if (cpu_model > 1 && ((cpuid_eax >> 12) & 3) == 2)
+ strcpy (cpu_brand, " Dual");
+ }
+ else if (cpu_family == 6 && cpu_model < 8)
+ {
+ switch (cpu_model)
+ {
+ case 1:
+ strcpy (cpu_brand, " Pro");
+ break;
+ case 3:
+ strcpy (cpu_brand, " II");
+ break;
+ case 5:
+ strcpy (cpu_brand, " II Xeon");
+ break;
+ case 6:
+ strcpy (cpu_brand, " Celeron");
+ break;
+ case 7:
+ strcpy (cpu_brand, " III");
+ break;
+ }
+ }
+ }
+ else if (amd_p)
+ {
+ switch (cpu_family)
+ {
+ case 4:
+ strcpy (cpu_brand, "486/5x86");
+ break;
+ case 5:
+ switch (cpu_model)
+ {
+ case 0:
+ case 1:
+ case 2:
+ case 3:
+ strcpy (cpu_brand, "-K5");
+ break;
+ case 6:
+ case 7:
+ strcpy (cpu_brand, "-K6");
+ break;
+ case 8:
+ strcpy (cpu_brand, "-K6-2");
+ break;
+ case 9:
+ strcpy (cpu_brand, "-K6-III");
+ break;
+ }
+ break;
+ case 6:
+ switch (cpu_model)
+ {
+ case 1:
+ case 2:
+ case 4:
+ strcpy (cpu_brand, " Athlon");
+ break;
+ case 3:
+ strcpy (cpu_brand, " Duron");
+ break;
+ }
+ break;
+ }
+ }
+ xsnprintf (cpu_string, sizeof (cpu_string), "%s%s Model %d Stepping %d",
+ intel_p ? "Pentium" : (amd_p ? "AMD" : (hygon_p ? "Hygon" : "ix86")),
+ cpu_brand, cpu_model, cpuid_eax & 0xf);
+ printfi_filtered (31, "%s\n", cpu_string);
+ if (((cpuid_edx & (6 | (0x0d << 23))) != 0)
+ || ((cpuid_edx & 1) == 0)
+ || ((amd_p || hygon_p) && (cpuid_edx & (3 << 30)) != 0))
+ {
+ puts_filtered ("CPU Features...................");
+ /* We only list features which might be useful in the DPMI
+ environment. */
+ if ((cpuid_edx & 1) == 0)
+ puts_filtered ("No FPU "); /* It's unusual to not have an FPU. */
+ if ((cpuid_edx & (1 << 1)) != 0)
+ puts_filtered ("VME ");
+ if ((cpuid_edx & (1 << 2)) != 0)
+ puts_filtered ("DE ");
+ if ((cpuid_edx & (1 << 4)) != 0)
+ puts_filtered ("TSC ");
+ if ((cpuid_edx & (1 << 23)) != 0)
+ puts_filtered ("MMX ");
+ if ((cpuid_edx & (1 << 25)) != 0)
+ puts_filtered ("SSE ");
+ if ((cpuid_edx & (1 << 26)) != 0)
+ puts_filtered ("SSE2 ");
+ if (amd_p || hygon_p)
+ {
+ if ((cpuid_edx & (1 << 31)) != 0)
+ puts_filtered ("3DNow! ");
+ if ((cpuid_edx & (1 << 30)) != 0)
+ puts_filtered ("3DNow!Ext");
+ }
+ puts_filtered ("\n");
+ }
+ }
+ puts_filtered ("\n");
+ printf_filtered ("DOS Version....................%s %s.%s",
+ _os_flavor, u.release, u.version);
+ if (true_dos_version != advertized_dos_version)
+ printf_filtered (" (disguised as v%d.%d)", _osmajor, _osminor);
+ puts_filtered ("\n");
+ if (!windows_major)
+ go32_get_windows_version ();
+ if (windows_major != 0xff)
+ {
+ const char *windows_flavor;
+
+ printf_filtered ("Windows Version................%d.%02d (Windows ",
+ windows_major, windows_minor);
+ switch (windows_major)
+ {
+ case 3:
+ windows_flavor = "3.X";
+ break;
+ case 4:
+ switch (windows_minor)
+ {
+ case 0:
+ windows_flavor = "95, 95A, or 95B";
+ break;
+ case 3:
+ windows_flavor = "95B OSR2.1 or 95C OSR2.5";
+ break;
+ case 10:
+ windows_flavor = "98 or 98 SE";
+ break;
+ case 90:
+ windows_flavor = "ME";
+ break;
+ default:
+ windows_flavor = "9X";
+ break;
+ }
+ break;
+ default:
+ windows_flavor = "??";
+ break;
+ }
+ printf_filtered ("%s)\n", windows_flavor);
+ }
+ else if (true_dos_version == 0x532 && advertized_dos_version == 0x500)
+ printf_filtered ("Windows Version................"
+ "Windows NT family (W2K/XP/W2K3/Vista/W2K8)\n");
+ puts_filtered ("\n");
+ /* On some versions of Windows, __dpmi_get_capabilities returns
+ zero, but the buffer is not filled with info, so we fill the
+ buffer with a known pattern and test for it afterwards. */
+ memcpy (dpmi_vendor_info, test_pattern, sizeof(dpmi_vendor_info));
+ dpmi_vendor_available =
+ __dpmi_get_capabilities (&dpmi_flags, dpmi_vendor_info);
+ if (dpmi_vendor_available == 0
+ && memcmp (dpmi_vendor_info, test_pattern,
+ sizeof(dpmi_vendor_info)) != 0)
+ {
+ /* The DPMI spec says the vendor string should be ASCIIZ, but
+ I don't trust the vendors to follow that... */
+ if (!memchr (&dpmi_vendor_info[2], 0, 126))
+ dpmi_vendor_info[128] = '\0';
+ printf_filtered ("DPMI Host......................"
+ "%s v%d.%d (capabilities: %#x)\n",
+ &dpmi_vendor_info[2],
+ (unsigned)dpmi_vendor_info[0],
+ (unsigned)dpmi_vendor_info[1],
+ ((unsigned)dpmi_flags & 0x7f));
+ }
+ else
+ printf_filtered ("DPMI Host......................(Info not available)\n");
+ __dpmi_get_version (&dpmi_version_data);
+ printf_filtered ("DPMI Version...................%d.%02d\n",
+ dpmi_version_data.major, dpmi_version_data.minor);
+ printf_filtered ("DPMI Info......................"
+ "%s-bit DPMI, with%s Virtual Memory support\n",
+ (dpmi_version_data.flags & 1) ? "32" : "16",
+ (dpmi_version_data.flags & 4) ? "" : "out");
+ printfi_filtered (31, "Interrupts reflected to %s mode\n",
+ (dpmi_version_data.flags & 2) ? "V86" : "Real");
+ printfi_filtered (31, "Processor type: i%d86\n",
+ dpmi_version_data.cpu);
+ printfi_filtered (31, "PIC base interrupt: Master: %#x Slave: %#x\n",
+ dpmi_version_data.master_pic, dpmi_version_data.slave_pic);
+
+ /* a_tss is only initialized when the debuggee is first run. */
+ if (prog_has_started)
+ {
+ __asm__ __volatile__ ("pushfl ; popl %0" : "=g" (eflags));
+ printf_filtered ("Protection....................."
+ "Ring %d (in %s), with%s I/O protection\n",
+ a_tss.tss_cs & 3, (a_tss.tss_cs & 4) ? "LDT" : "GDT",
+ (a_tss.tss_cs & 3) > ((eflags >> 12) & 3) ? "" : "out");
+ }
+ puts_filtered ("\n");
+ __dpmi_get_free_memory_information (&mem_info);
+ print_mem (mem_info.total_number_of_physical_pages,
+ "DPMI Total Physical Memory.....", 1);
+ print_mem (mem_info.total_number_of_free_pages,
+ "DPMI Free Physical Memory......", 1);
+ print_mem (mem_info.size_of_paging_file_partition_in_pages,
+ "DPMI Swap Space................", 1);
+ print_mem (mem_info.linear_address_space_size_in_pages,
+ "DPMI Total Linear Address Size.", 1);
+ print_mem (mem_info.free_linear_address_space_in_pages,
+ "DPMI Free Linear Address Size..", 1);
+ print_mem (mem_info.largest_available_free_block_in_bytes,
+ "DPMI Largest Free Memory Block.", 0);
+
+ regs.h.ah = 0x48;
+ regs.x.bx = 0xffff;
+ __dpmi_int (0x21, ®s);
+ print_mem (regs.x.bx << 4, "Free DOS Memory................", 0);
+ regs.x.ax = 0x5800;
+ __dpmi_int (0x21, ®s);
+ if ((regs.x.flags & 1) == 0)
+ {
+ static const char *dos_hilo[] = {
+ "Low", "", "", "", "High", "", "", "", "High, then Low"
+ };
+ static const char *dos_fit[] = {
+ "First", "Best", "Last"
+ };
+ int hilo_idx = (regs.x.ax >> 4) & 0x0f;
+ int fit_idx = regs.x.ax & 0x0f;
+
+ if (hilo_idx > 8)
+ hilo_idx = 0;
+ if (fit_idx > 2)
+ fit_idx = 0;
+ printf_filtered ("DOS Memory Allocation..........%s memory, %s fit\n",
+ dos_hilo[hilo_idx], dos_fit[fit_idx]);
+ regs.x.ax = 0x5802;
+ __dpmi_int (0x21, ®s);
+ if ((regs.x.flags & 1) != 0)
+ regs.h.al = 0;
+ printfi_filtered (31, "UMBs %sin DOS memory chain\n",
+ regs.h.al == 0 ? "not " : "");
+ }
+}
+
+struct seg_descr {
+ unsigned short limit0;
+ unsigned short base0;
+ unsigned char base1;
+ unsigned stype:5;
+ unsigned dpl:2;
+ unsigned present:1;
+ unsigned limit1:4;
+ unsigned available:1;
+ unsigned dummy:1;
+ unsigned bit32:1;
+ unsigned page_granular:1;
+ unsigned char base2;
+} __attribute__ ((packed));
+
+struct gate_descr {
+ unsigned short offset0;
+ unsigned short selector;
+ unsigned param_count:5;
+ unsigned dummy:3;
+ unsigned stype:5;
+ unsigned dpl:2;
+ unsigned present:1;
+ unsigned short offset1;
+} __attribute__ ((packed));
+
+/* Read LEN bytes starting at logical address ADDR, and put the result
+ into DEST. Return 1 if success, zero if not. */
+static int
+read_memory_region (unsigned long addr, void *dest, size_t len)
+{
+ unsigned long dos_ds_limit = __dpmi_get_segment_limit (_dos_ds);
+ int retval = 1;
+
+ /* For the low memory, we can simply use _dos_ds. */
+ if (addr <= dos_ds_limit - len)
+ dosmemget (addr, len, dest);
+ else
+ {
+ /* For memory above 1MB we need to set up a special segment to
+ be able to access that memory. */
+ int sel = __dpmi_allocate_ldt_descriptors (1);
+
+ if (sel <= 0)
+ retval = 0;
+ else
+ {
+ int access_rights = __dpmi_get_descriptor_access_rights (sel);
+ size_t segment_limit = len - 1;
+
+ /* Make sure the crucial bits in the descriptor access
+ rights are set correctly. Some DPMI providers might barf
+ if we set the segment limit to something that is not an
+ integral multiple of 4KB pages if the granularity bit is
+ not set to byte-granular, even though the DPMI spec says
+ it's the host's responsibility to set that bit correctly. */
+ if (len > 1024 * 1024)
+ {
+ access_rights |= 0x8000;
+ /* Page-granular segments should have the low 12 bits of
+ the limit set. */
+ segment_limit |= 0xfff;
+ }
+ else
+ access_rights &= ~0x8000;
+
+ if (__dpmi_set_segment_base_address (sel, addr) != -1
+ && __dpmi_set_descriptor_access_rights (sel, access_rights) != -1
+ && __dpmi_set_segment_limit (sel, segment_limit) != -1
+ /* W2K silently fails to set the segment limit, leaving
+ it at zero; this test avoids the resulting crash. */
+ && __dpmi_get_segment_limit (sel) >= segment_limit)
+ movedata (sel, 0, _my_ds (), (unsigned)dest, len);
+ else
+ retval = 0;
+
+ __dpmi_free_ldt_descriptor (sel);
+ }
+ }
+ return retval;
+}
+
+/* Get a segment descriptor stored at index IDX in the descriptor
+ table whose base address is TABLE_BASE. Return the descriptor
+ type, or -1 if failure. */
+static int
+get_descriptor (unsigned long table_base, int idx, void *descr)
+{
+ unsigned long addr = table_base + idx * 8; /* 8 bytes per entry */
+
+ if (read_memory_region (addr, descr, 8))
+ return (int)((struct seg_descr *)descr)->stype;
+ return -1;
+}
+
+struct dtr_reg {
+ unsigned short limit __attribute__((packed));
+ unsigned long base __attribute__((packed));
+};
+
+/* Display a segment descriptor stored at index IDX in a descriptor
+ table whose type is TYPE and whose base address is BASE_ADDR. If
+ FORCE is non-zero, display even invalid descriptors. */
+static void
+display_descriptor (unsigned type, unsigned long base_addr, int idx, int force)
+{
+ struct seg_descr descr;
+ struct gate_descr gate;
+
+ /* Get the descriptor from the table. */
+ if (idx == 0 && type == 0)
+ puts_filtered ("0x000: null descriptor\n");
+ else if (get_descriptor (base_addr, idx, &descr) != -1)
+ {
+ /* For each type of descriptor table, this has a bit set if the
+ corresponding type of selectors is valid in that table. */
+ static unsigned allowed_descriptors[] = {
+ 0xffffdafeL, /* GDT */
+ 0x0000c0e0L, /* IDT */
+ 0xffffdafaL /* LDT */
+ };
+
+ /* If the program hasn't started yet, assume the debuggee will
+ have the same CPL as the debugger. */
+ int cpl = prog_has_started ? (a_tss.tss_cs & 3) : _my_cs () & 3;
+ unsigned long limit = (descr.limit1 << 16) | descr.limit0;
+
+ if (descr.present
+ && (allowed_descriptors[type] & (1 << descr.stype)) != 0)
+ {
+ printf_filtered ("0x%03x: ",
+ type == 1
+ ? idx : (idx * 8) | (type ? (cpl | 4) : 0));
+ if (descr.page_granular)
+ limit = (limit << 12) | 0xfff; /* big segment: low 12 bit set */
+ if (descr.stype == 1 || descr.stype == 2 || descr.stype == 3
+ || descr.stype == 9 || descr.stype == 11
+ || (descr.stype >= 16 && descr.stype < 32))
+ printf_filtered ("base=0x%02x%02x%04x limit=0x%08lx",
+ descr.base2, descr.base1, descr.base0, limit);
+
+ switch (descr.stype)
+ {
+ case 1:
+ case 3:
+ printf_filtered (" 16-bit TSS (task %sactive)",
+ descr.stype == 3 ? "" : "in");
+ break;
+ case 2:
+ puts_filtered (" LDT");
+ break;
+ case 4:
+ memcpy (&gate, &descr, sizeof gate);
+ printf_filtered ("selector=0x%04x offs=0x%04x%04x",
+ gate.selector, gate.offset1, gate.offset0);
+ printf_filtered (" 16-bit Call Gate (params=%d)",
+ gate.param_count);
+ break;
+ case 5:
+ printf_filtered ("TSS selector=0x%04x", descr.base0);
+ printfi_filtered (16, "Task Gate");
+ break;
+ case 6:
+ case 7:
+ memcpy (&gate, &descr, sizeof gate);
+ printf_filtered ("selector=0x%04x offs=0x%04x%04x",
+ gate.selector, gate.offset1, gate.offset0);
+ printf_filtered (" 16-bit %s Gate",
+ descr.stype == 6 ? "Interrupt" : "Trap");
+ break;
+ case 9:
+ case 11:
+ printf_filtered (" 32-bit TSS (task %sactive)",
+ descr.stype == 3 ? "" : "in");
+ break;
+ case 12:
+ memcpy (&gate, &descr, sizeof gate);
+ printf_filtered ("selector=0x%04x offs=0x%04x%04x",
+ gate.selector, gate.offset1, gate.offset0);
+ printf_filtered (" 32-bit Call Gate (params=%d)",
+ gate.param_count);
+ break;
+ case 14:
+ case 15:
+ memcpy (&gate, &descr, sizeof gate);
+ printf_filtered ("selector=0x%04x offs=0x%04x%04x",
+ gate.selector, gate.offset1, gate.offset0);
+ printf_filtered (" 32-bit %s Gate",
+ descr.stype == 14 ? "Interrupt" : "Trap");
+ break;
+ case 16: /* data segments */
+ case 17:
+ case 18:
+ case 19:
+ case 20:
+ case 21:
+ case 22:
+ case 23:
+ printf_filtered (" %s-bit Data (%s Exp-%s%s)",
+ descr.bit32 ? "32" : "16",
+ descr.stype & 2
+ ? "Read/Write," : "Read-Only, ",
+ descr.stype & 4 ? "down" : "up",
+ descr.stype & 1 ? "" : ", N.Acc");
+ break;
+ case 24: /* code segments */
+ case 25:
+ case 26:
+ case 27:
+ case 28:
+ case 29:
+ case 30:
+ case 31:
+ printf_filtered (" %s-bit Code (%s, %sConf%s)",
+ descr.bit32 ? "32" : "16",
+ descr.stype & 2 ? "Exec/Read" : "Exec-Only",
+ descr.stype & 4 ? "" : "N.",
+ descr.stype & 1 ? "" : ", N.Acc");
+ break;
+ default:
+ printf_filtered ("Unknown type 0x%02x", descr.stype);
+ break;
+ }
+ puts_filtered ("\n");
+ }
+ else if (force)
+ {
+ printf_filtered ("0x%03x: ",
+ type == 1
+ ? idx : (idx * 8) | (type ? (cpl | 4) : 0));
+ if (!descr.present)
+ puts_filtered ("Segment not present\n");
+ else
+ printf_filtered ("Segment type 0x%02x is invalid in this table\n",
+ descr.stype);
+ }
+ }
+ else if (force)
+ printf_filtered ("0x%03x: Cannot read this descriptor\n", idx);
+}
+
+static void
+go32_sldt (const char *arg, int from_tty)
+{
+ struct dtr_reg gdtr;
+ unsigned short ldtr = 0;
+ int ldt_idx;
+ struct seg_descr ldt_descr;
+ long ldt_entry = -1L;
+ int cpl = (prog_has_started ? a_tss.tss_cs : _my_cs ()) & 3;
+
+ if (arg && *arg)
+ {
+ arg = skip_spaces (arg);
+
+ if (*arg)
+ {
+ ldt_entry = parse_and_eval_long (arg);
+ if (ldt_entry < 0
+ || (ldt_entry & 4) == 0
+ || (ldt_entry & 3) != (cpl & 3))
+ error (_("Invalid LDT entry 0x%03lx."), (unsigned long)ldt_entry);
+ }
+ }
+
+ __asm__ __volatile__ ("sgdt %0" : "=m" (gdtr) : /* no inputs */ );
+ __asm__ __volatile__ ("sldt %0" : "=m" (ldtr) : /* no inputs */ );
+ ldt_idx = ldtr / 8;
+ if (ldt_idx == 0)
+ puts_filtered ("There is no LDT.\n");
+ /* LDT's entry in the GDT must have the type LDT, which is 2. */
+ else if (get_descriptor (gdtr.base, ldt_idx, &ldt_descr) != 2)
+ printf_filtered ("LDT is present (at %#x), but unreadable by GDB.\n",
+ ldt_descr.base0
+ | (ldt_descr.base1 << 16)
+ | (ldt_descr.base2 << 24));
+ else
+ {
+ unsigned base =
+ ldt_descr.base0
+ | (ldt_descr.base1 << 16)
+ | (ldt_descr.base2 << 24);
+ unsigned limit = ldt_descr.limit0 | (ldt_descr.limit1 << 16);
+ int max_entry;
+
+ if (ldt_descr.page_granular)
+ /* Page-granular segments must have the low 12 bits of their
+ limit set. */
+ limit = (limit << 12) | 0xfff;
+ /* LDT cannot have more than 8K 8-byte entries, i.e. more than
+ 64KB. */
+ if (limit > 0xffff)
+ limit = 0xffff;
+
+ max_entry = (limit + 1) / 8;
+
+ if (ldt_entry >= 0)
+ {
+ if (ldt_entry > limit)
+ error (_("Invalid LDT entry %#lx: outside valid limits [0..%#x]"),
+ (unsigned long)ldt_entry, limit);
+
+ display_descriptor (ldt_descr.stype, base, ldt_entry / 8, 1);
+ }
+ else
+ {
+ int i;
+
+ for (i = 0; i < max_entry; i++)
+ display_descriptor (ldt_descr.stype, base, i, 0);
+ }
+ }
+}
+
+static void
+go32_sgdt (const char *arg, int from_tty)
+{
+ struct dtr_reg gdtr;
+ long gdt_entry = -1L;
+ int max_entry;
+
+ if (arg && *arg)
+ {
+ arg = skip_spaces (arg);
+
+ if (*arg)
+ {
+ gdt_entry = parse_and_eval_long (arg);
+ if (gdt_entry < 0 || (gdt_entry & 7) != 0)
+ error (_("Invalid GDT entry 0x%03lx: "
+ "not an integral multiple of 8."),
+ (unsigned long)gdt_entry);
+ }
+ }
+
+ __asm__ __volatile__ ("sgdt %0" : "=m" (gdtr) : /* no inputs */ );
+ max_entry = (gdtr.limit + 1) / 8;
+
+ if (gdt_entry >= 0)
+ {
+ if (gdt_entry > gdtr.limit)
+ error (_("Invalid GDT entry %#lx: outside valid limits [0..%#x]"),
+ (unsigned long)gdt_entry, gdtr.limit);
+
+ display_descriptor (0, gdtr.base, gdt_entry / 8, 1);
+ }
+ else
+ {
+ int i;
+
+ for (i = 0; i < max_entry; i++)
+ display_descriptor (0, gdtr.base, i, 0);
+ }
+}
+
+static void
+go32_sidt (const char *arg, int from_tty)
+{
+ struct dtr_reg idtr;
+ long idt_entry = -1L;
+ int max_entry;
+
+ if (arg && *arg)
+ {
+ arg = skip_spaces (arg);
+
+ if (*arg)
+ {
+ idt_entry = parse_and_eval_long (arg);
+ if (idt_entry < 0)
+ error (_("Invalid (negative) IDT entry %ld."), idt_entry);
+ }
+ }
+
+ __asm__ __volatile__ ("sidt %0" : "=m" (idtr) : /* no inputs */ );
+ max_entry = (idtr.limit + 1) / 8;
+ if (max_entry > 0x100) /* No more than 256 entries. */
+ max_entry = 0x100;
+
+ if (idt_entry >= 0)
+ {
+ if (idt_entry > idtr.limit)
+ error (_("Invalid IDT entry %#lx: outside valid limits [0..%#x]"),
+ (unsigned long)idt_entry, idtr.limit);
+
+ display_descriptor (1, idtr.base, idt_entry, 1);
+ }
+ else
+ {
+ int i;
+
+ for (i = 0; i < max_entry; i++)
+ display_descriptor (1, idtr.base, i, 0);
+ }
+}
+
+/* Cached linear address of the base of the page directory. For
+ now, available only under CWSDPMI. Code based on ideas and
+ suggestions from Charles Sandmann <sandmann@clio.rice.edu>. */
+static unsigned long pdbr;
+
+static unsigned long
+get_cr3 (void)
+{
+ unsigned offset;
+ unsigned taskreg;
+ unsigned long taskbase, cr3;
+ struct dtr_reg gdtr;
+
+ if (pdbr > 0 && pdbr <= 0xfffff)
+ return pdbr;
+
+ /* Get the linear address of GDT and the Task Register. */
+ __asm__ __volatile__ ("sgdt %0" : "=m" (gdtr) : /* no inputs */ );
+ __asm__ __volatile__ ("str %0" : "=m" (taskreg) : /* no inputs */ );
+
+ /* Task Register is a segment selector for the TSS of the current
+ task. Therefore, it can be used as an index into the GDT to get
+ at the segment descriptor for the TSS. To get the index, reset
+ the low 3 bits of the selector (which give the CPL). Add 2 to the
+ offset to point to the 3 low bytes of the base address. */
+ offset = gdtr.base + (taskreg & 0xfff8) + 2;
+
+
+ /* CWSDPMI's task base is always under the 1MB mark. */
+ if (offset > 0xfffff)
+ return 0;
+
+ _farsetsel (_dos_ds);
+ taskbase = _farnspeekl (offset) & 0xffffffU;
+ taskbase += _farnspeekl (offset + 2) & 0xff000000U;
+ if (taskbase > 0xfffff)
+ return 0;
+
+ /* CR3 (a.k.a. PDBR, the Page Directory Base Register) is stored at
+ offset 1Ch in the TSS. */
+ cr3 = _farnspeekl (taskbase + 0x1c) & ~0xfff;
+ if (cr3 > 0xfffff)
+ {
+#if 0 /* Not fully supported yet. */
+ /* The Page Directory is in UMBs. In that case, CWSDPMI puts
+ the first Page Table right below the Page Directory. Thus,
+ the first Page Table's entry for its own address and the Page
+ Directory entry for that Page Table will hold the same
+ physical address. The loop below searches the entire UMB
+ range of addresses for such an occurrence. */
+ unsigned long addr, pte_idx;
+
+ for (addr = 0xb0000, pte_idx = 0xb0;
+ pte_idx < 0xff;
+ addr += 0x1000, pte_idx++)
+ {
+ if (((_farnspeekl (addr + 4 * pte_idx) & 0xfffff027) ==
+ (_farnspeekl (addr + 0x1000) & 0xfffff027))
+ && ((_farnspeekl (addr + 4 * pte_idx + 4) & 0xfffff000) == cr3))
+ {
+ cr3 = addr + 0x1000;
+ break;
+ }
+ }
+#endif
+
+ if (cr3 > 0xfffff)
+ cr3 = 0;
+ }
+
+ return cr3;
+}
+
+/* Return the N'th Page Directory entry. */
+static unsigned long
+get_pde (int n)
+{
+ unsigned long pde = 0;
+
+ if (pdbr && n >= 0 && n < 1024)
+ {
+ pde = _farpeekl (_dos_ds, pdbr + 4*n);
+ }
+ return pde;
+}
+
+/* Return the N'th entry of the Page Table whose Page Directory entry
+ is PDE. */
+static unsigned long
+get_pte (unsigned long pde, int n)
+{
+ unsigned long pte = 0;
+
+ /* pde & 0x80 tests the 4MB page bit. We don't support 4MB
+ page tables, for now. */
+ if ((pde & 1) && !(pde & 0x80) && n >= 0 && n < 1024)
+ {
+ pde &= ~0xfff; /* Clear non-address bits. */
+ pte = _farpeekl (_dos_ds, pde + 4*n);
+ }
+ return pte;
+}
+
+/* Display a Page Directory or Page Table entry. IS_DIR, if non-zero,
+ says this is a Page Directory entry. If FORCE is non-zero, display
+ the entry even if its Present flag is off. OFF is the offset of the
+ address from the page's base address. */
+static void
+display_ptable_entry (unsigned long entry, int is_dir, int force, unsigned off)
+{
+ if ((entry & 1) != 0)
+ {
+ printf_filtered ("Base=0x%05lx000", entry >> 12);
+ if ((entry & 0x100) && !is_dir)
+ puts_filtered (" Global");
+ if ((entry & 0x40) && !is_dir)
+ puts_filtered (" Dirty");
+ printf_filtered (" %sAcc.", (entry & 0x20) ? "" : "Not-");
+ printf_filtered (" %sCached", (entry & 0x10) ? "" : "Not-");
+ printf_filtered (" Write-%s", (entry & 8) ? "Thru" : "Back");
+ printf_filtered (" %s", (entry & 4) ? "Usr" : "Sup");
+ printf_filtered (" Read-%s", (entry & 2) ? "Write" : "Only");
+ if (off)
+ printf_filtered (" +0x%x", off);
+ puts_filtered ("\n");
+ }
+ else if (force)
+ printf_filtered ("Page%s not present or not supported; value=0x%lx.\n",
+ is_dir ? " Table" : "", entry >> 1);
+}
+
+static void
+go32_pde (const char *arg, int from_tty)
+{
+ long pde_idx = -1, i;
+
+ if (arg && *arg)
+ {
+ arg = skip_spaces (arg);
+
+ if (*arg)
+ {
+ pde_idx = parse_and_eval_long (arg);
+ if (pde_idx < 0 || pde_idx >= 1024)
+ error (_("Entry %ld is outside valid limits [0..1023]."), pde_idx);
+ }
+ }
+
+ pdbr = get_cr3 ();
+ if (!pdbr)
+ puts_filtered ("Access to Page Directories is "
+ "not supported on this system.\n");
+ else if (pde_idx >= 0)
+ display_ptable_entry (get_pde (pde_idx), 1, 1, 0);
+ else
+ for (i = 0; i < 1024; i++)
+ display_ptable_entry (get_pde (i), 1, 0, 0);
+}
+
+/* A helper function to display entries in a Page Table pointed to by
+ the N'th entry in the Page Directory. If FORCE is non-zero, say
+ something even if the Page Table is not accessible. */
+static void
+display_page_table (long n, int force)
+{
+ unsigned long pde = get_pde (n);
+
+ if ((pde & 1) != 0)
+ {
+ int i;
+
+ printf_filtered ("Page Table pointed to by "
+ "Page Directory entry 0x%lx:\n", n);
+ for (i = 0; i < 1024; i++)
+ display_ptable_entry (get_pte (pde, i), 0, 0, 0);
+ puts_filtered ("\n");
+ }
+ else if (force)
+ printf_filtered ("Page Table not present; value=0x%lx.\n", pde >> 1);
+}
+
+static void
+go32_pte (const char *arg, int from_tty)
+{
+ long pde_idx = -1L, i;
+
+ if (arg && *arg)
+ {
+ arg = skip_spaces (arg);
+
+ if (*arg)
+ {
+ pde_idx = parse_and_eval_long (arg);
+ if (pde_idx < 0 || pde_idx >= 1024)
+ error (_("Entry %ld is outside valid limits [0..1023]."), pde_idx);
+ }
+ }
+
+ pdbr = get_cr3 ();
+ if (!pdbr)
+ puts_filtered ("Access to Page Tables is not supported on this system.\n");
+ else if (pde_idx >= 0)
+ display_page_table (pde_idx, 1);
+ else
+ for (i = 0; i < 1024; i++)
+ display_page_table (i, 0);
+}
+
+static void
+go32_pte_for_address (const char *arg, int from_tty)
+{
+ CORE_ADDR addr = 0, i;
+
+ if (arg && *arg)
+ {
+ arg = skip_spaces (arg);
+
+ if (*arg)
+ addr = parse_and_eval_address (arg);
+ }
+ if (!addr)
+ error_no_arg (_("linear address"));
+
+ pdbr = get_cr3 ();
+ if (!pdbr)
+ puts_filtered ("Access to Page Tables is not supported on this system.\n");
+ else
+ {
+ int pde_idx = (addr >> 22) & 0x3ff;
+ int pte_idx = (addr >> 12) & 0x3ff;
+ unsigned offs = addr & 0xfff;
+
+ printf_filtered ("Page Table entry for address %s:\n",
+ hex_string(addr));
+ display_ptable_entry (get_pte (get_pde (pde_idx), pte_idx), 0, 1, offs);
+ }
+}
+
+static struct cmd_list_element *info_dos_cmdlist = NULL;
+
+void _initialize_go32_nat ();
+void
+_initialize_go32_nat ()
+{
+ x86_dr_low.set_control = go32_set_dr7;
+ x86_dr_low.set_addr = go32_set_dr;
+ x86_dr_low.get_status = go32_get_dr6;
+ x86_dr_low.get_control = go32_get_dr7;
+ x86_dr_low.get_addr = go32_get_dr;
+ x86_set_debug_register_length (4);
+
+ add_inf_child_target (&the_go32_nat_target);
+
+ /* Initialize child's cwd as empty to be initialized when starting
+ the child. */
+ *child_cwd = 0;
+
+ /* Initialize child's command line storage. */
+ if (redir_debug_init (&child_cmd) == -1)
+ internal_error (__FILE__, __LINE__,
+ _("Cannot allocate redirection storage: "
+ "not enough memory.\n"));
+
+ /* We are always processing GCC-compiled programs. */
+ processing_gcc_compilation = 2;
+
+ add_basic_prefix_cmd ("dos", class_info, _("\
+Print information specific to DJGPP (aka MS-DOS) debugging."),
+ &info_dos_cmdlist, "info dos ", 0, &infolist);
+
+ add_cmd ("sysinfo", class_info, go32_sysinfo, _("\
+Display information about the target system, including CPU, OS, DPMI, etc."),
+ &info_dos_cmdlist);
+ add_cmd ("ldt", class_info, go32_sldt, _("\
+Display entries in the LDT (Local Descriptor Table).\n\
+Entry number (an expression) as an argument means display only that entry."),
+ &info_dos_cmdlist);
+ add_cmd ("gdt", class_info, go32_sgdt, _("\
+Display entries in the GDT (Global Descriptor Table).\n\
+Entry number (an expression) as an argument means display only that entry."),
+ &info_dos_cmdlist);
+ add_cmd ("idt", class_info, go32_sidt, _("\
+Display entries in the IDT (Interrupt Descriptor Table).\n\
+Entry number (an expression) as an argument means display only that entry."),
+ &info_dos_cmdlist);
+ add_cmd ("pde", class_info, go32_pde, _("\
+Display entries in the Page Directory.\n\
+Entry number (an expression) as an argument means display only that entry."),
+ &info_dos_cmdlist);
+ add_cmd ("pte", class_info, go32_pte, _("\
+Display entries in Page Tables.\n\
+Entry number (an expression) as an argument means display only entries\n\
+from the Page Table pointed to by the specified Page Directory entry."),
+ &info_dos_cmdlist);
+ add_cmd ("address-pte", class_info, go32_pte_for_address, _("\
+Display a Page Table entry for a linear address.\n\
+The address argument must be a linear address, after adding to\n\
+it the base address of the appropriate segment.\n\
+The base address of variables and functions in the debuggee's data\n\
+or code segment is stored in the variable __djgpp_base_address,\n\
+so use `__djgpp_base_address + (char *)&var' as the argument.\n\
+For other segments, look up their base address in the output of\n\
+the `info dos ldt' command."),
+ &info_dos_cmdlist);
+}
+
+pid_t
+tcgetpgrp (int fd)
+{
+ if (isatty (fd))
+ return SOME_PID;
+ errno = ENOTTY;
+ return -1;
+}
+
+int
+tcsetpgrp (int fd, pid_t pgid)
+{
+ if (isatty (fd) && pgid == SOME_PID)
+ return 0;
+ errno = pgid == SOME_PID ? ENOTTY : ENOSYS;
+ return -1;
+}