/home/stan/gdb/src/gdb/inf-child.c

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/* Default child (native) target interface, for GDB when running under
   Unix.

   Copyright (C) 1988-2013 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 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/>.  */

#include "defs.h"
#include "regcache.h"
#include "memattr.h"
#include "symtab.h"
#include "target.h"
#include "inferior.h"
#include "gdb_string.h"
#include "gdb_stat.h"
#include "inf-child.h"
#include "gdb/fileio.h"
#include "agent.h"
#include "gdb_wait.h"
#include "filestuff.h"

#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>

/* Helper function for child_wait and the derivatives of child_wait.
   HOSTSTATUS is the waitstatus from wait() or the equivalent; store our
   translation of that in OURSTATUS.  */
void
store_waitstatus (struct target_waitstatus *ourstatus, int hoststatus)
{
  if (WIFEXITED (hoststatus))
    {
      ourstatus->kind = TARGET_WAITKIND_EXITED;
      ourstatus->value.integer = WEXITSTATUS (hoststatus);
    }
  else if (!WIFSTOPPED (hoststatus))
    {
      ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
      ourstatus->value.sig = gdb_signal_from_host (WTERMSIG (hoststatus));
    }
  else
    {
      ourstatus->kind = TARGET_WAITKIND_STOPPED;
      ourstatus->value.sig = gdb_signal_from_host (WSTOPSIG (hoststatus));
    }
}

/* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
   for all registers.  */

static void
inf_child_fetch_inferior_registers (struct target_ops *ops,
                                    struct regcache *regcache, int regnum)
{
  if (regnum == -1)
    {
      for (regnum = 0;
           regnum < gdbarch_num_regs (get_regcache_arch (regcache));
           regnum++)
        regcache_raw_supply (regcache, regnum, NULL);
    }
  else
    regcache_raw_supply (regcache, regnum, NULL);
}

/* Store register REGNUM back into the inferior.  If REGNUM is -1, do
   this for all registers (including the floating point registers).  */

static void
inf_child_store_inferior_registers (struct target_ops *ops,
                                    struct regcache *regcache, int regnum)
{
}

static void
inf_child_post_attach (int pid)
{
  /* This version of Unix doesn't require a meaningful "post attach"
     operation by a debugger.  */
}

/* Get ready to modify the registers array.  On machines which store
   individual registers, this doesn't need to do anything.  On
   machines which store all the registers in one fell swoop, this
   makes sure that registers contains all the registers from the
   program being debugged.  */

static void
inf_child_prepare_to_store (struct regcache *regcache)
{
}

static void
inf_child_open (char *arg, int from_tty)
{
  error (_("Use the \"run\" command to start a Unix child process."));
}

static void
inf_child_post_startup_inferior (ptid_t ptid)
{
  /* This version of Unix doesn't require a meaningful "post startup
     inferior" operation by a debugger.  */
}

static int
inf_child_follow_fork (struct target_ops *ops, int follow_child,
                       int detach_fork)
{
  /* This version of Unix doesn't support following fork or vfork
     events.  */
  return 0;
}

static int
inf_child_can_run (void)
{
  return 1;
}

static char *
inf_child_pid_to_exec_file (int pid)
{
  /* This version of Unix doesn't support translation of a process ID
     to the filename of the executable file.  */
  return NULL;
}


/* Target file operations.  */

static int
inf_child_fileio_open_flags_to_host (int fileio_open_flags, int *open_flags_p)
{
  int open_flags = 0;

  if (fileio_open_flags & ~FILEIO_O_SUPPORTED)
    return -1;

  if (fileio_open_flags & FILEIO_O_CREAT)
    open_flags |= O_CREAT;
  if (fileio_open_flags & FILEIO_O_EXCL)
    open_flags |= O_EXCL;
  if (fileio_open_flags & FILEIO_O_TRUNC)
    open_flags |= O_TRUNC;
  if (fileio_open_flags & FILEIO_O_APPEND)
    open_flags |= O_APPEND;
  if (fileio_open_flags & FILEIO_O_RDONLY)
    open_flags |= O_RDONLY;
  if (fileio_open_flags & FILEIO_O_WRONLY)
    open_flags |= O_WRONLY;
  if (fileio_open_flags & FILEIO_O_RDWR)
    open_flags |= O_RDWR;
/* On systems supporting binary and text mode, always open files in
   binary mode. */
#ifdef O_BINARY
  open_flags |= O_BINARY;
#endif

  *open_flags_p = open_flags;
  return 0;
}

static int
inf_child_errno_to_fileio_error (int errnum)
{
  switch (errnum)
    {
      case EPERM:
        return FILEIO_EPERM;
      case ENOENT:
        return FILEIO_ENOENT;
      case EINTR:
        return FILEIO_EINTR;
      case EIO:
        return FILEIO_EIO;
      case EBADF:
        return FILEIO_EBADF;
      case EACCES:
        return FILEIO_EACCES;
      case EFAULT:
        return FILEIO_EFAULT;
      case EBUSY:
        return FILEIO_EBUSY;
      case EEXIST:
        return FILEIO_EEXIST;
      case ENODEV:
        return FILEIO_ENODEV;
      case ENOTDIR:
        return FILEIO_ENOTDIR;
      case EISDIR:
        return FILEIO_EISDIR;
      case EINVAL:
        return FILEIO_EINVAL;
      case ENFILE:
        return FILEIO_ENFILE;
      case EMFILE:
        return FILEIO_EMFILE;
      case EFBIG:
        return FILEIO_EFBIG;
      case ENOSPC:
        return FILEIO_ENOSPC;
      case ESPIPE:
        return FILEIO_ESPIPE;
      case EROFS:
        return FILEIO_EROFS;
      case ENOSYS:
        return FILEIO_ENOSYS;
      case ENAMETOOLONG:
        return FILEIO_ENAMETOOLONG;
    }
  return FILEIO_EUNKNOWN;
}

/* Open FILENAME on the target, using FLAGS and MODE.  Return a
   target file descriptor, or -1 if an error occurs (and set
   *TARGET_ERRNO).  */
static int
inf_child_fileio_open (const char *filename, int flags, int mode,
                       int *target_errno)
{
  int nat_flags;
  int fd;

  if (inf_child_fileio_open_flags_to_host (flags, &nat_flags) == -1)
    {
      *target_errno = FILEIO_EINVAL;
      return -1;
    }

  /* We do not need to convert MODE, since the fileio protocol uses
     the standard values.  */
  fd = gdb_open_cloexec (filename, nat_flags, mode);
  if (fd == -1)
    *target_errno = inf_child_errno_to_fileio_error (errno);

  return fd;
}

/* Write up to LEN bytes from WRITE_BUF to FD on the target.
   Return the number of bytes written, or -1 if an error occurs
   (and set *TARGET_ERRNO).  */
static int
inf_child_fileio_pwrite (int fd, const gdb_byte *write_buf, int len,
                         ULONGEST offset, int *target_errno)
{
  int ret;

#ifdef HAVE_PWRITE
  ret = pwrite (fd, write_buf, len, (long) offset);
#else
  ret = -1;
#endif
  /* If we have no pwrite or it failed for this file, use lseek/write.  */
  if (ret == -1)
    {
      ret = lseek (fd, (long) offset, SEEK_SET);
      if (ret != -1)
        ret = write (fd, write_buf, len);
    }

  if (ret == -1)
    *target_errno = inf_child_errno_to_fileio_error (errno);

  return ret;
}

/* Read up to LEN bytes FD on the target into READ_BUF.
   Return the number of bytes read, or -1 if an error occurs
   (and set *TARGET_ERRNO).  */
static int
inf_child_fileio_pread (int fd, gdb_byte *read_buf, int len,
                        ULONGEST offset, int *target_errno)
{
  int ret;

#ifdef HAVE_PREAD
  ret = pread (fd, read_buf, len, (long) offset);
#else
  ret = -1;
#endif
  /* If we have no pread or it failed for this file, use lseek/read.  */
  if (ret == -1)
    {
      ret = lseek (fd, (long) offset, SEEK_SET);
      if (ret != -1)
        ret = read (fd, read_buf, len);
    }

  if (ret == -1)
    *target_errno = inf_child_errno_to_fileio_error (errno);

  return ret;
}

/* Close FD on the target.  Return 0, or -1 if an error occurs
   (and set *TARGET_ERRNO).  */
static int
inf_child_fileio_close (int fd, int *target_errno)
{
  int ret;

  ret = close (fd);
  if (ret == -1)
    *target_errno = inf_child_errno_to_fileio_error (errno);

  return ret;
}

/* Unlink FILENAME on the target.  Return 0, or -1 if an error
   occurs (and set *TARGET_ERRNO).  */
static int
inf_child_fileio_unlink (const char *filename, int *target_errno)
{
  int ret;

  ret = unlink (filename);
  if (ret == -1)
    *target_errno = inf_child_errno_to_fileio_error (errno);

  return ret;
}

/* Read value of symbolic link FILENAME on the target.  Return a
   null-terminated string allocated via xmalloc, or NULL if an error
   occurs (and set *TARGET_ERRNO).  */
static char *
inf_child_fileio_readlink (const char *filename, int *target_errno)
{
  /* We support readlink only on systems that also provide a compile-time
     maximum path length (PATH_MAX), at least for now.  */
#if defined (HAVE_READLINK) && defined (PATH_MAX)
  char buf[PATH_MAX];
  int len;
  char *ret;

  len = readlink (filename, buf, sizeof buf);
  if (len < 0)
    {
      *target_errno = inf_child_errno_to_fileio_error (errno);
      return NULL;
    }

  ret = xmalloc (len + 1);
  memcpy (ret, buf, len);
  ret[len] = '\0';
  return ret;
#else
  *target_errno = FILEIO_ENOSYS;
  return NULL;
#endif
}

static int
inf_child_use_agent (int use)
{
  if (agent_loaded_p ())
    {
      use_agent = use;
      return 1;
    }
  else
    return 0;
}

static int
inf_child_can_use_agent (void)
{
  return agent_loaded_p ();
}

struct target_ops *
inf_child_target (void)
{
  struct target_ops *t = XZALLOC (struct target_ops);

  t->to_shortname = "child";
  t->to_longname = "Unix child process";
  t->to_doc = "Unix child process (started by the \"run\" command).";
  t->to_open = inf_child_open;
  t->to_post_attach = inf_child_post_attach;
  t->to_fetch_registers = inf_child_fetch_inferior_registers;
  t->to_store_registers = inf_child_store_inferior_registers;
  t->to_prepare_to_store = inf_child_prepare_to_store;
  t->to_insert_breakpoint = memory_insert_breakpoint;
  t->to_remove_breakpoint = memory_remove_breakpoint;
  t->to_terminal_init = terminal_init_inferior;
  t->to_terminal_inferior = terminal_inferior;
  t->to_terminal_ours_for_output = terminal_ours_for_output;
  t->to_terminal_save_ours = terminal_save_ours;
  t->to_terminal_ours = terminal_ours;
  t->to_terminal_info = child_terminal_info;
  t->to_post_startup_inferior = inf_child_post_startup_inferior;
  t->to_follow_fork = inf_child_follow_fork;
  t->to_can_run = inf_child_can_run;
  t->to_pid_to_exec_file = inf_child_pid_to_exec_file;
  t->to_stratum = process_stratum;
  t->to_has_all_memory = default_child_has_all_memory;
  t->to_has_memory = default_child_has_memory;
  t->to_has_stack = default_child_has_stack;
  t->to_has_registers = default_child_has_registers;
  t->to_has_execution = default_child_has_execution;
  t->to_fileio_open = inf_child_fileio_open;
  t->to_fileio_pwrite = inf_child_fileio_pwrite;
  t->to_fileio_pread = inf_child_fileio_pread;
  t->to_fileio_close = inf_child_fileio_close;
  t->to_fileio_unlink = inf_child_fileio_unlink;
  t->to_fileio_readlink = inf_child_fileio_readlink;
  t->to_magic = OPS_MAGIC;
  t->to_use_agent = inf_child_use_agent;
  t->to_can_use_agent = inf_child_can_use_agent;
  return t;
}