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- /* Native debugging support for Intel x86 running DJGPP.
- Copyright (C) 1997-2022 Free Software Foundation, Inc.
- Written by Robert Hoehne.
- 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 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.
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
- /* 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.
- 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 *, target_wait_flags) 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,
- target_wait_flags 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->set_exited (a_tss.tss_eax & 0xff);
- else
- {
- status->set_stopped (GDB_SIGNAL_UNKNOWN);
- for (i = 0; sig_map[i].go32_sig != -1; i++)
- {
- if (a_tss.tss_irqn == sig_map[i].go32_sig)
- {
- #if __DJGPP_MINOR__ < 3
- status->set_stopped (sig_map[i].gdb_sig);
- if (status->sig () != GDB_SIGNAL_TRAP)
- status->set_signalled (status->sig ());
- #else
- status->set_stopped (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 ()
- {
- gdb_printf ("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
- inf = current_inferior ();
- inferior_appeared (inf, SOME_PID);
- if (!inf->target_is_pushed (this))
- inf->push_target (this);
- thread_info *thr = add_thread_silent (ptid_t (SOME_PID));
- switch_to_thread (thr);
- clear_proceed_status (0);
- insert_breakpoints ();
- prog_has_started = 1;
- }
- void
- go32_nat_target::mourn_inferior ()
- {
- 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 ();
- 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)
- {
- CONTROL = val;
- }
- /* 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;
- }
- /* 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. */
- 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)
- {
- gdb_printf ("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)
- gdb_printf ("\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)
- gdb_printf
- ("\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))
- gdb_printf
- ("\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;
- gdb_puts (header);
- if (datum > 1024)
- {
- gdb_printf ("%lu KB", datum >> 10);
- if (datum > 1024 * 1024)
- gdb_printf (" (%lu MB)", datum >> 20);
- }
- else
- gdb_printf ("%lu Bytes", datum);
- gdb_puts ("\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
- }
- gdb_printf ("CPU Type.......................%s", u.machine);
- if (cpuid_vendor[0])
- gdb_printf (" (%s)", cpuid_vendor);
- gdb_puts ("\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);
- gdb_printf ("%*s%s\n", 31, "", cpu_string);
- if (((cpuid_edx & (6 | (0x0d << 23))) != 0)
- || ((cpuid_edx & 1) == 0)
- || ((amd_p || hygon_p) && (cpuid_edx & (3 << 30)) != 0))
- {
- gdb_puts ("CPU Features...................");
- /* We only list features which might be useful in the DPMI
- environment. */
- if ((cpuid_edx & 1) == 0)
- gdb_puts ("No FPU "); /* It's unusual to not have an FPU. */
- if ((cpuid_edx & (1 << 1)) != 0)
- gdb_puts ("VME ");
- if ((cpuid_edx & (1 << 2)) != 0)
- gdb_puts ("DE ");
- if ((cpuid_edx & (1 << 4)) != 0)
- gdb_puts ("TSC ");
- if ((cpuid_edx & (1 << 23)) != 0)
- gdb_puts ("MMX ");
- if ((cpuid_edx & (1 << 25)) != 0)
- gdb_puts ("SSE ");
- if ((cpuid_edx & (1 << 26)) != 0)
- gdb_puts ("SSE2 ");
- if (amd_p || hygon_p)
- {
- if ((cpuid_edx & (1 << 31)) != 0)
- gdb_puts ("3DNow! ");
- if ((cpuid_edx & (1 << 30)) != 0)
- gdb_puts ("3DNow!Ext");
- }
- gdb_puts ("\n");
- }
- }
- gdb_puts ("\n");
- gdb_printf ("DOS Version....................%s %s.%s",
- _os_flavor, u.release, u.version);
- if (true_dos_version != advertized_dos_version)
- gdb_printf (" (disguised as v%d.%d)", _osmajor, _osminor);
- gdb_puts ("\n");
- if (!windows_major)
- go32_get_windows_version ();
- if (windows_major != 0xff)
- {
- const char *windows_flavor;
- gdb_printf ("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;
- }
- gdb_printf ("%s)\n", windows_flavor);
- }
- else if (true_dos_version == 0x532 && advertized_dos_version == 0x500)
- gdb_printf ("Windows Version................"
- "Windows NT family (W2K/XP/W2K3/Vista/W2K8)\n");
- gdb_puts ("\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';
- gdb_printf ("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
- gdb_printf ("DPMI Host......................(Info not available)\n");
- __dpmi_get_version (&dpmi_version_data);
- gdb_printf ("DPMI Version...................%d.%02d\n",
- dpmi_version_data.major, dpmi_version_data.minor);
- gdb_printf ("DPMI Info......................"
- "%s-bit DPMI, with%s Virtual Memory support\n",
- (dpmi_version_data.flags & 1) ? "32" : "16",
- (dpmi_version_data.flags & 4) ? "" : "out");
- gdb_printf ("%*sInterrupts reflected to %s mode\n", 31, "",
- (dpmi_version_data.flags & 2) ? "V86" : "Real");
- gdb_printf ("%*sProcessor type: i%d86\n", 31, "",
- dpmi_version_data.cpu);
- gdb_printf ("%*sPIC base interrupt: Master: %#x Slave: %#x\n", 31, "",
- 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));
- gdb_printf ("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");
- }
- gdb_puts ("\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;
- gdb_printf ("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;
- gdb_printf ("%*sUMBs %sin DOS memory chain\n", 31, "",
- 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)
- gdb_puts ("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)
- {
- gdb_printf ("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))
- gdb_printf ("base=0x%02x%02x%04x limit=0x%08lx",
- descr.base2, descr.base1, descr.base0, limit);
- switch (descr.stype)
- {
- case 1:
- case 3:
- gdb_printf (" 16-bit TSS (task %sactive)",
- descr.stype == 3 ? "" : "in");
- break;
- case 2:
- gdb_puts (" LDT");
- break;
- case 4:
- memcpy (&gate, &descr, sizeof gate);
- gdb_printf ("selector=0x%04x offs=0x%04x%04x",
- gate.selector, gate.offset1, gate.offset0);
- gdb_printf (" 16-bit Call Gate (params=%d)",
- gate.param_count);
- break;
- case 5:
- gdb_printf ("TSS selector=0x%04x", descr.base0);
- gdb_printf ("%*sTask Gate", 16, "");
- break;
- case 6:
- case 7:
- memcpy (&gate, &descr, sizeof gate);
- gdb_printf ("selector=0x%04x offs=0x%04x%04x",
- gate.selector, gate.offset1, gate.offset0);
- gdb_printf (" 16-bit %s Gate",
- descr.stype == 6 ? "Interrupt" : "Trap");
- break;
- case 9:
- case 11:
- gdb_printf (" 32-bit TSS (task %sactive)",
- descr.stype == 3 ? "" : "in");
- break;
- case 12:
- memcpy (&gate, &descr, sizeof gate);
- gdb_printf ("selector=0x%04x offs=0x%04x%04x",
- gate.selector, gate.offset1, gate.offset0);
- gdb_printf (" 32-bit Call Gate (params=%d)",
- gate.param_count);
- break;
- case 14:
- case 15:
- memcpy (&gate, &descr, sizeof gate);
- gdb_printf ("selector=0x%04x offs=0x%04x%04x",
- gate.selector, gate.offset1, gate.offset0);
- gdb_printf (" 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:
- gdb_printf (" %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:
- gdb_printf (" %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:
- gdb_printf ("Unknown type 0x%02x", descr.stype);
- break;
- }
- gdb_puts ("\n");
- }
- else if (force)
- {
- gdb_printf ("0x%03x: ",
- type == 1
- ? idx : (idx * 8) | (type ? (cpl | 4) : 0));
- if (!descr.present)
- gdb_puts ("Segment not present\n");
- else
- gdb_printf ("Segment type 0x%02x is invalid in this table\n",
- descr.stype);
- }
- }
- else if (force)
- gdb_printf ("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)
- gdb_puts ("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)
- gdb_printf ("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)
- {
- gdb_printf ("Base=0x%05lx000", entry >> 12);
- if ((entry & 0x100) && !is_dir)
- gdb_puts (" Global");
- if ((entry & 0x40) && !is_dir)
- gdb_puts (" Dirty");
- gdb_printf (" %sAcc.", (entry & 0x20) ? "" : "Not-");
- gdb_printf (" %sCached", (entry & 0x10) ? "" : "Not-");
- gdb_printf (" Write-%s", (entry & 8) ? "Thru" : "Back");
- gdb_printf (" %s", (entry & 4) ? "Usr" : "Sup");
- gdb_printf (" Read-%s", (entry & 2) ? "Write" : "Only");
- if (off)
- gdb_printf (" +0x%x", off);
- gdb_puts ("\n");
- }
- else if (force)
- gdb_printf ("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)
- gdb_puts ("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;
- gdb_printf ("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);
- gdb_puts ("\n");
- }
- else if (force)
- gdb_printf ("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)
- gdb_puts ("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)
- gdb_puts ("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;
- gdb_printf ("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, 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;
- }
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