485 lines
11 KiB
C
485 lines
11 KiB
C
/* Low level interface to ptrace, for the remote server for GDB.
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Copyright 1995, 1996, 1998, 1999, 2000, 2001, 2002
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Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "server.h"
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#include "linux-low.h"
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#include <sys/wait.h>
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#include <stdio.h>
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#include <sys/param.h>
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#include <sys/dir.h>
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#include <sys/ptrace.h>
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#include <sys/user.h>
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#include <signal.h>
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#include <sys/ioctl.h>
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#include <fcntl.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#define PTRACE_ARG3_TYPE long
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#define PTRACE_XFER_TYPE long
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#ifdef HAVE_LINUX_REGSETS
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static int use_regsets_p = 1;
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#endif
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extern int errno;
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#ifdef HAVE_LINUX_USRREGS
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extern int num_regs;
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extern int regmap[];
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#endif
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/* Start an inferior process and returns its pid.
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ALLARGS is a vector of program-name and args. */
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int
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create_inferior (char *program, char **allargs)
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{
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int pid;
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pid = fork ();
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if (pid < 0)
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perror_with_name ("fork");
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if (pid == 0)
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{
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ptrace (PTRACE_TRACEME, 0, 0, 0);
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execv (program, allargs);
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fprintf (stderr, "Cannot exec %s: %s.\n", program,
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strerror (errno));
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fflush (stderr);
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_exit (0177);
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}
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return pid;
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}
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/* Attach to an inferior process. */
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int
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myattach (int pid)
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{
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if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0)
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{
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fprintf (stderr, "Cannot attach to process %d: %s (%d)\n", pid,
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errno < sys_nerr ? sys_errlist[errno] : "unknown error",
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errno);
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fflush (stderr);
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_exit (0177);
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}
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return 0;
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}
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/* Kill the inferior process. Make us have no inferior. */
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void
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kill_inferior (void)
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{
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if (inferior_pid == 0)
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return;
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ptrace (PTRACE_KILL, inferior_pid, 0, 0);
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wait (0);
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}
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/* Return nonzero if the given thread is still alive. */
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int
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mythread_alive (int pid)
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{
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return 1;
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}
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/* Wait for process, returns status */
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unsigned char
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mywait (char *status)
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{
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int pid;
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int w;
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enable_async_io ();
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pid = waitpid (inferior_pid, &w, 0);
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disable_async_io ();
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if (pid != inferior_pid)
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perror_with_name ("wait");
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if (WIFEXITED (w))
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{
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fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
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*status = 'W';
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return ((unsigned char) WEXITSTATUS (w));
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}
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else if (!WIFSTOPPED (w))
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{
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fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
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*status = 'X';
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return ((unsigned char) WTERMSIG (w));
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}
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fetch_inferior_registers (0);
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*status = 'T';
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return ((unsigned char) WSTOPSIG (w));
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}
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/* Resume execution of the inferior process.
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If STEP is nonzero, single-step it.
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If SIGNAL is nonzero, give it that signal. */
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void
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myresume (int step, int signal)
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{
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errno = 0;
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ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, inferior_pid, 1, signal);
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if (errno)
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perror_with_name ("ptrace");
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}
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#ifdef HAVE_LINUX_USRREGS
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#define REGISTER_RAW_SIZE(regno) register_size((regno))
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int
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register_addr (int regnum)
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{
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int addr;
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if (regnum < 0 || regnum >= num_regs)
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error ("Invalid register number %d.", regnum);
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addr = regmap[regnum];
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if (addr == -1)
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addr = 0;
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return addr;
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}
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/* Fetch one register. */
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static void
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fetch_register (int regno)
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{
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CORE_ADDR regaddr;
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register int i;
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if (regno >= num_regs)
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return;
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if (cannot_fetch_register (regno))
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return;
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regaddr = register_addr (regno);
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if (regaddr == -1)
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return;
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for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))
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{
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errno = 0;
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*(PTRACE_XFER_TYPE *) (register_data (regno) + i) =
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ptrace (PTRACE_PEEKUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr, 0);
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regaddr += sizeof (PTRACE_XFER_TYPE);
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if (errno != 0)
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{
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/* Warning, not error, in case we are attached; sometimes the
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kernel doesn't let us at the registers. */
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char *err = strerror (errno);
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char *msg = alloca (strlen (err) + 128);
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sprintf (msg, "reading register %d: %s", regno, err);
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error (msg);
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goto error_exit;
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}
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}
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error_exit:;
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}
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/* Fetch all registers, or just one, from the child process. */
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static void
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usr_fetch_inferior_registers (int regno)
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{
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if (regno == -1 || regno == 0)
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for (regno = 0; regno < num_regs; regno++)
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fetch_register (regno);
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else
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fetch_register (regno);
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}
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/* Store our register values back into the inferior.
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If REGNO is -1, do this for all registers.
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Otherwise, REGNO specifies which register (so we can save time). */
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static void
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usr_store_inferior_registers (int regno)
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{
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CORE_ADDR regaddr;
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int i;
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if (regno >= 0)
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{
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if (regno >= num_regs)
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return;
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if (cannot_store_register (regno))
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return;
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regaddr = register_addr (regno);
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if (regaddr == -1)
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return;
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errno = 0;
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for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))
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{
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errno = 0;
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ptrace (PTRACE_POKEUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
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*(int *) (register_data (regno) + i));
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if (errno != 0)
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{
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/* Warning, not error, in case we are attached; sometimes the
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kernel doesn't let us at the registers. */
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char *err = strerror (errno);
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char *msg = alloca (strlen (err) + 128);
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sprintf (msg, "writing register %d: %s",
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regno, err);
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error (msg);
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return;
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}
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regaddr += sizeof (int);
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}
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}
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else
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for (regno = 0; regno < num_regs; regno++)
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store_inferior_registers (regno);
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}
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#endif /* HAVE_LINUX_USRREGS */
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#ifdef HAVE_LINUX_REGSETS
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static int
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regsets_fetch_inferior_registers (void)
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{
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struct regset_info *regset;
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regset = target_regsets;
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while (regset->size >= 0)
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{
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void *buf;
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int res;
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if (regset->size == 0)
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{
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regset ++;
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continue;
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}
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buf = malloc (regset->size);
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res = ptrace (regset->get_request, inferior_pid, 0, (int) buf);
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if (res < 0)
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{
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if (errno == EIO)
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{
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/* If we get EIO on the first regset, do not try regsets again.
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If we get EIO on a later regset, disable that regset. */
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if (regset == target_regsets)
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{
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use_regsets_p = 0;
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return -1;
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}
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else
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{
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regset->size = 0;
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continue;
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}
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}
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else
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{
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perror ("Warning: ptrace(regsets_fetch_inferior_registers)");
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}
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}
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regset->store_function (buf);
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regset ++;
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}
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}
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static int
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regsets_store_inferior_registers (void)
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{
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struct regset_info *regset;
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regset = target_regsets;
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while (regset->size >= 0)
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{
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void *buf;
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int res;
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if (regset->size == 0)
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{
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regset ++;
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continue;
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}
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buf = malloc (regset->size);
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regset->fill_function (buf);
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res = ptrace (regset->set_request, inferior_pid, 0, (int) buf);
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if (res < 0)
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{
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if (errno == EIO)
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{
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/* If we get EIO on the first regset, do not try regsets again.
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If we get EIO on a later regset, disable that regset. */
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if (regset == target_regsets)
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{
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use_regsets_p = 0;
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return -1;
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}
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else
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{
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regset->size = 0;
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continue;
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}
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}
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else
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{
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perror ("Warning: ptrace(regsets_fetch_inferior_registers)");
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}
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}
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regset ++;
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}
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}
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#endif /* HAVE_LINUX_REGSETS */
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void
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fetch_inferior_registers (int regno)
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{
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#ifdef HAVE_LINUX_REGSETS
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if (use_regsets_p)
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{
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if (regsets_fetch_inferior_registers () == 0)
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return;
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}
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#endif
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#ifdef HAVE_LINUX_USRREGS
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usr_fetch_inferior_registers (regno);
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#endif
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}
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void
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store_inferior_registers (int regno)
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{
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#ifdef HAVE_LINUX_REGSETS
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if (use_regsets_p)
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{
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if (regsets_store_inferior_registers () == 0)
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return;
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}
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#endif
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#ifdef HAVE_LINUX_USRREGS
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usr_store_inferior_registers (regno);
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#endif
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}
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/* Copy LEN bytes from inferior's memory starting at MEMADDR
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to debugger memory starting at MYADDR. */
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void
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read_inferior_memory (CORE_ADDR memaddr, char *myaddr, int len)
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{
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register int i;
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/* Round starting address down to longword boundary. */
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register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE);
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/* Round ending address up; get number of longwords that makes. */
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register int count
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= (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1)
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/ sizeof (PTRACE_XFER_TYPE);
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/* Allocate buffer of that many longwords. */
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register PTRACE_XFER_TYPE *buffer
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= (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
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/* Read all the longwords */
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for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
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{
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buffer[i] = ptrace (PTRACE_PEEKTEXT, inferior_pid, (PTRACE_ARG3_TYPE) addr, 0);
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}
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/* Copy appropriate bytes out of the buffer. */
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memcpy (myaddr, (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), len);
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}
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/* Copy LEN bytes of data from debugger memory at MYADDR
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to inferior's memory at MEMADDR.
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On failure (cannot write the inferior)
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returns the value of errno. */
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int
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write_inferior_memory (CORE_ADDR memaddr, char *myaddr, int len)
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{
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register int i;
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/* Round starting address down to longword boundary. */
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register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE);
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/* Round ending address up; get number of longwords that makes. */
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register int count
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= (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) / sizeof (PTRACE_XFER_TYPE);
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/* Allocate buffer of that many longwords. */
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register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
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extern int errno;
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/* Fill start and end extra bytes of buffer with existing memory data. */
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buffer[0] = ptrace (PTRACE_PEEKTEXT, inferior_pid,
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(PTRACE_ARG3_TYPE) addr, 0);
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if (count > 1)
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{
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buffer[count - 1]
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= ptrace (PTRACE_PEEKTEXT, inferior_pid,
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(PTRACE_ARG3_TYPE) (addr + (count - 1)
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* sizeof (PTRACE_XFER_TYPE)),
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0);
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}
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/* Copy data to be written over corresponding part of buffer */
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memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), myaddr, len);
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/* Write the entire buffer. */
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for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
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{
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errno = 0;
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ptrace (PTRACE_POKETEXT, inferior_pid, (PTRACE_ARG3_TYPE) addr, buffer[i]);
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if (errno)
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return errno;
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}
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return 0;
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}
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void
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initialize_low (void)
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{
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init_registers ();
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}
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