binutils-gdb/gdb/i386lynx-nat.c

305 lines
7.6 KiB
C

/* Native-dependent code for Lynx running on i386's, for GDB.
Copyright 1988, 1989, 1991, 1992, 1993
Free Software Foundation, Inc.
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 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. */
#include "defs.h"
#include "frame.h"
#include "inferior.h"
#include "gdbcore.h"
#include "target.h"
#include <sys/ptrace.h>
#include "/usr/include/sys/wait.h"
/* these values indicate the offset of the named register in the econtext
structure */
#define EAX 10
#define ECX 9
#define EDX 8
#define EBX 7
#define ESP 16
#define EBP 5
#define ESI 4
#define EDI 3
#define EIP 13
#define EFL 15
#define CS 14
#define SS 17
#define DS 2
#define ES 1
/* Currently these are not being used. So set them to 0 */
#define FS 0
#define GS 0
/* this table must line up with REGISTER_NAMES in m-i386.h */
static unsigned int regmap[] =
{
EAX, ECX, EDX, EBX,
ESP, EBP, ESI, EDI,
EIP, EFL, CS, SS,
DS, ES, FS, GS,
};
/* Return the address in the core dump or inferior of register REGNO.
BLOCKEND is the address of the econtext structure */
static unsigned int
register_addr (regno, blockend)
int regno, blockend;
{
if (regno < 0 || regno >= NUM_REGS)
error ("Invalid register number %d.", regno);
return (blockend + regmap[regno] * sizeof (long));
}
/* Fetch one register. */
static void
fetch_register (regno, offset, bpid)
int regno, bpid;
unsigned int offset;
{
unsigned int regaddr;
char buf[MAX_REGISTER_RAW_SIZE];
char mess[128]; /* For messages */
int i;
regaddr = register_addr (regno, offset);
for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
{
errno = 0;
*(int *) &buf[i] = ptrace (PTRACE_PEEKTHREAD, bpid,
(PTRACE_ARG3_TYPE) regaddr, 0);
regaddr += sizeof (int);
if (errno != 0)
{
sprintf (mess, "reading register %s (#%d)", reg_names[regno], regno);
perror_with_name (mess);
}
}
supply_register (regno, buf);
}
/* Store our register values back into the inferior.
If REGNO is -1, do this for all registers.
Otherwise, REGNO specifies which register (so we can save time). */
static void
store_register (regno, offset, bpid)
int regno, bpid;
unsigned int offset;
{
unsigned int regaddr;
char mess[128];
extern char registers[];
int i;
regaddr = register_addr (regno, offset);
for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof(int))
{
errno = 0;
ptrace (PTRACE_POKEUSER, bpid, (PTRACE_ARG3_TYPE) regaddr,
*(int *) &registers[REGISTER_BYTE (regno) + i]);
if (errno != 0)
{
sprintf (mess, "writing register number %d(%d)", regno, i);
perror_with_name (mess);
}
regaddr += sizeof(int);
}
}
/* return an offset for use with register_addr() */
static unsigned int
fetch_offset (pid)
int pid;
{
struct st_entry s;
unsigned int specpage_off, offset = (char *) &s.ecp - (char *) &s;
errno = 0;
specpage_off = ptrace (PTRACE_THREADUSER, pid, (PTRACE_ARG3_TYPE) 0, 0);
if (errno != 0)
perror_with_name ("ptrace");
errno = 0;
offset = ptrace (PTRACE_PEEKTHREAD, pid, (PTRACE_ARG3_TYPE) offset, 0)
- specpage_off;
if (errno != 0)
perror_with_name ("ptrace");
return offset;
}
/* Fetch all registers, or just one, from the child process. */
void
fetch_inferior_registers (regno)
int regno;
{
unsigned int offset = fetch_offset (inferior_pid);
if (regno == -1)
{
for (regno = 0; regno < NUM_REGS; regno++)
fetch_register (regno, offset, inferior_pid);
}
else
fetch_register (regno, offset, inferior_pid);
}
/* Store all registers, or just one, to the child process. */
void
store_inferior_registers (regno)
int regno;
{
unsigned int offset = fetch_offset (inferior_pid);
if (regno == -1)
{
for (regno = 0; regno < NUM_REGS; regno++)
store_register (regno, offset, inferior_pid);
}
else
store_register (regno, offset, inferior_pid);
}
/* Extract the register values out of the core file and store
them where `read_register' will find them.
CORE_REG_SECT points to the register values themselves, read into memory.
CORE_REG_SIZE is the size of that area.
WHICH says which set of registers we are handling (0 = int, 2 = float
on machines where they are discontiguous).
REG_ADDR is the offset from u.u_ar0 to the register values relative to
core_reg_sect. This is used with old-fashioned core files to
locate the registers in a large upage-plus-stack ".reg" section.
Original upage address X is at location core_reg_sect+x+reg_addr.
*/
void
fetch_core_registers (core_reg_sect, core_reg_size, which, reg_addr)
char *core_reg_sect;
unsigned core_reg_size;
int which;
unsigned reg_addr;
{
struct st_entry s;
unsigned int regno, addr;
for (regno = 0; regno < NUM_REGS; regno++)
{
addr = register_addr (regno, (char *) &s.ec - (char *) &s);
supply_register (regno, core_reg_sect + addr);
}
}
/* Wait for child to do something. Return pid of child, or -1 in case
of error; store status through argument pointer STATUS. */
int
child_wait (status)
int *status;
{
int pid;
int save_errno;
int thread;
while (1)
{
int sig;
if (attach_flag)
set_sigint_trap(); /* Causes SIGINT to be passed on to the
attached process. */
pid = wait (status);
save_errno = errno;
if (attach_flag)
clear_sigint_trap();
if (pid == -1)
{
if (save_errno == EINTR)
continue;
fprintf (stderr, "Child process unexpectedly missing: %s.\n",
safe_strerror (save_errno));
*status = 42; /* Claim it exited with signal 42 */
return -1;
}
if (pid != PIDGET (inferior_pid)) /* Some other process?!? */
continue;
/* thread = WIFTID (*status);*/
thread = *status >> 16;
/* Initial thread value can only be acquired via wait, so we have to
resort to this hack. */
if (TIDGET (inferior_pid) == 0)
{
inferior_pid = BUILDPID (inferior_pid, thread);
add_thread (inferior_pid);
}
pid = BUILDPID (pid, thread);
return pid;
}
}
/* Return the PC of the caller from the call frame. Assumes the subr prologue
has already been executed, and the frame pointer setup. If this is the
outermost frame, we check to see if we are in a system call by examining the
previous instruction. If so, then the return PC is actually at SP+4 because
system calls use a different calling sequence. */
CORE_ADDR
i386lynx_saved_pc_after_call (frame)
struct frame_info *frame;
{
char opcode[7];
static const char call_inst[] = {0x9a, 0, 0, 0, 0, 8, 0}; /* lcall 0x8,0x0 */
read_memory (frame->pc - 7, opcode, 7);
if (memcmp (opcode, call_inst, 7) == 0)
return read_memory_integer (read_register (SP_REGNUM) + 4, 4);
return read_memory_integer (read_register (SP_REGNUM), 4);
}
/* Convert a Lynx process ID to a string. Returns the string in a static
buffer. */
char *
i386lynx_pid_to_str (pid)
int pid;
{
static char buf[40];
sprintf (buf, "process %d thread %d", PIDGET (pid), TIDGET (pid));
return buf;
}