libc/winsup/cygwin/fhandler_virtual.cc

/* fhandler_virtual.cc: base fhandler class for virtual filesystems

   Copyright 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012,
   2013 Red Hat, Inc.

This file is part of Cygwin.

This software is a copyrighted work licensed under the terms of the
Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
details. */

#include "winsup.h"
#include <cygwin/acl.h>
#include <sys/statvfs.h>
#include "cygerrno.h"
#include "path.h"
#include "fhandler.h"
#include "dtable.h"
#include "cygheap.h"
#include "sync.h"
#include "child_info.h"

#include <dirent.h>

fhandler_virtual::fhandler_virtual ():
  fhandler_base (), filebuf (NULL), fileid (-1)
{
}

fhandler_virtual::~fhandler_virtual ()
{
  if (filebuf)
    {
      cfree (filebuf);
      filebuf = NULL;
    }
}

void
fhandler_virtual::fixup_after_exec ()
{
}

DIR *
fhandler_virtual::opendir (int fd)
{
  DIR *dir;
  DIR *res = NULL;
  size_t len;

  if (exists () <= 0)
    set_errno (ENOTDIR);
  else if ((len = strlen (get_name ())) > PATH_MAX - 3)
    set_errno (ENAMETOOLONG);
  else if ((dir = (DIR *) malloc (sizeof (DIR))) == NULL)
    set_errno (ENOMEM);
  else if ((dir->__d_dirname = (char *) malloc (len + 3)) == NULL)
    {
      free (dir);
      set_errno (ENOMEM);
    }
  else if ((dir->__d_dirent =
      (struct dirent *) malloc (sizeof (struct dirent))) == NULL)
    {
      free (dir->__d_dirname);
      free (dir);
      set_errno (ENOMEM);
    }
  else
    {
      strcpy (dir->__d_dirname, get_name ());
      dir->__d_dirent->__d_version = __DIRENT_VERSION;
      dir->__d_cookie = __DIRENT_COOKIE;
      dir->__handle = INVALID_HANDLE_VALUE;
      dir->__d_position = 0;
      dir->__flags = 0;

      if (fd >= 0)
	{
	  dir->__d_fd = fd;
	  dir->__fh = this;
	  res = dir;
	}
      else
	{
	  cygheap_fdnew cfd;
	  if (cfd >= 0 && open (O_RDONLY, 0))
	    {
	      cfd = this;
	      dir->__d_fd = cfd;
	      dir->__fh = this;
	      res = dir;
	    }
	}
      close_on_exec (true);
    }

  syscall_printf ("%p = opendir (%s)", res, get_name ());
  return res;
}

long
fhandler_virtual::telldir (DIR * dir)
{
  return dir->__d_position;
}

void
fhandler_virtual::seekdir (DIR * dir, long loc)
{
  dir->__flags |= dirent_saw_dot | dirent_saw_dot_dot;
  dir->__d_position = loc;
}

void
fhandler_virtual::rewinddir (DIR * dir)
{
  dir->__d_position = 0;
  dir->__flags |= dirent_saw_dot | dirent_saw_dot_dot;
}

int
fhandler_virtual::closedir (DIR * dir)
{
  return 0;
}

off_t
fhandler_virtual::lseek (off_t offset, int whence)
{
  /*
   * On Linux, when you lseek within a /proc file,
   * the contents of the file are updated.
   */
  if (!fill_filebuf ())
    return (off_t) -1;
  switch (whence)
    {
    case SEEK_SET:
      position = offset;
      break;
    case SEEK_CUR:
      position += offset;
      break;
    case SEEK_END:
      position = filesize + offset;
      break;
    default:
      set_errno (EINVAL);
      return (off_t) -1;
    }
  return position;
}

int
fhandler_virtual::dup (fhandler_base * child, int flags)
{
  int ret = fhandler_base::dup (child, flags);

  if (!ret)
    {
      fhandler_virtual *fhproc_child = (fhandler_virtual *) child;
      fhproc_child->filebuf = (char *) cmalloc_abort (HEAP_BUF, filesize);
      memcpy (fhproc_child->filebuf, filebuf, filesize);
    }
  return ret;
}

int
fhandler_virtual::close ()
{
  if (!have_execed)
    {
      if (filebuf)
	{
	  cfree (filebuf);
	  filebuf = NULL;
	}
    }
  return 0;
}

void __reg3
fhandler_virtual::read (void *ptr, size_t& len)
{
  if (len == 0)
    return;
  if (openflags & O_DIROPEN)
    {
      set_errno (EISDIR);
      len = (size_t) -1;
      return;
    }
  if (!filebuf)
    {
      len = (size_t) 0;
      return;
    }
  if ((ssize_t) len > filesize - position)
    len = (size_t) (filesize - position);
  if ((ssize_t) len < 0)
    len = 0;
  else
    memcpy (ptr, filebuf + position, len);
  position += len;
}

ssize_t __stdcall
fhandler_virtual::write (const void *ptr, size_t len)
{
  set_errno (EACCES);
  return -1;
}

/* low-level open for all proc files */
int
fhandler_virtual::open (int flags, mode_t mode)
{
  rbinary (true);
  wbinary (true);

  set_flags ((flags & ~O_TEXT) | O_BINARY);

  return 1;
}

virtual_ftype_t
fhandler_virtual::exists ()
{
  return virt_none;
}

bool
fhandler_virtual::fill_filebuf ()
{
  return true;
}

int
fhandler_virtual::fchmod (mode_t mode)
{
  /* Same as on Linux. */
  set_errno (EPERM);
  return -1;
}

int
fhandler_virtual::fchown (uid_t uid, gid_t gid)
{
  /* Same as on Linux. */
  set_errno (EPERM);
  return -1;
}

int
fhandler_virtual::facl (int cmd, int nentries, aclent_t *aclbufp)
{
  int res = fhandler_base::facl (cmd, nentries, aclbufp);
  if (res >= 0 && cmd == GETACL)
    {
      aclbufp[0].a_perm = (S_IRUSR | (pc.isdir () ? S_IXUSR : 0)) >> 6;
      aclbufp[1].a_perm = (S_IRGRP | (pc.isdir () ? S_IXGRP : 0)) >> 3;
      aclbufp[2].a_perm = S_IROTH | (pc.isdir () ? S_IXOTH : 0);
    }
  return res;
}

int __reg2
fhandler_virtual::fstatvfs (struct statvfs *sfs)
{
  /* Virtual file system.  Just return an empty buffer with a few values
     set to something useful.  Just as on Linux. */
  memset (sfs, 0, sizeof (*sfs));
  sfs->f_bsize = sfs->f_frsize = 4096;
  sfs->f_flag = ST_RDONLY;
  sfs->f_namemax = NAME_MAX;
  return 0;
}