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hurdlookup.c

/* Copyright (C) 1992,93,94,95,96,97,99,2001,2004
      Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <hurd.h>
#include <hurd/lookup.h>
#include <string.h>
#include <fcntl.h>


/* Translate the error from dir_lookup into the error the user sees.  */
static inline error_t
lookup_error (error_t error)
{
  switch (error)
    {
    case EOPNOTSUPP:
    case MIG_BAD_ID:
      /* These indicate that the server does not understand dir_lookup
       at all.  If it were a directory, it would, by definition.  */
      return ENOTDIR;
    default:
      return error;
    }
}

error_t
__hurd_file_name_lookup (error_t (*use_init_port)
                     (int which, error_t (*operate) (file_t)),
                   file_t (*get_dtable_port) (int fd),
                   error_t (*lookup)
                     (file_t dir, char *name, int flags, mode_t mode,
                      retry_type *do_retry, string_t retry_name,
                      mach_port_t *result),
                   const char *file_name, int flags, mode_t mode,
                   file_t *result)
{
  error_t err;
  enum retry_type doretry;
  char retryname[1024];       /* XXX string_t LOSES! */
  int startport;

  error_t lookup_op (mach_port_t startdir)
    {
      return lookup_error ((*lookup) (startdir, file_name, flags, mode,
                              &doretry, retryname, result));
    }

  if (! lookup)
    lookup = __dir_lookup;

  if (file_name[0] == '\0')
    return ENOENT;

  startport = (file_name[0] == '/') ? INIT_PORT_CRDIR : INIT_PORT_CWDIR;
  while (file_name[0] == '/')
    file_name++;

  if (flags & O_NOFOLLOW)     /* See lookup-retry.c about O_NOFOLLOW.  */
    flags |= O_NOTRANS;

  if (flags & O_DIRECTORY)
    {
      /* The caller wants to require that the file we look up is a directory.
       We can do this without an extra RPC by appending a trailing slash
       to the file name we look up.  */
      size_t len = strlen (file_name);
      if (len == 0)
      file_name = "/";
      else if (file_name[len - 1] != '/')
      {
        char *n = alloca (len + 2);
        memcpy (n, file_name, len);
        n[len] = '/';
        n[len + 1] = '\0';
        file_name = n;
      }
    }

  err = (*use_init_port) (startport, &lookup_op);
  if (! err)
    err = __hurd_file_name_lookup_retry (use_init_port, get_dtable_port,
                               lookup, doretry, retryname,
                               flags, mode, result);

  return err;
}
weak_alias (__hurd_file_name_lookup, hurd_file_name_lookup)

error_t
__hurd_file_name_split (error_t (*use_init_port)
                    (int which, error_t (*operate) (file_t)),
                  file_t (*get_dtable_port) (int fd),
                  error_t (*lookup)
                    (file_t dir, char *name, int flags, mode_t mode,
                     retry_type *do_retry, string_t retry_name,
                     mach_port_t *result),
                  const char *file_name,
                  file_t *dir, char **name)
{
  error_t addref (file_t crdir)
    {
      *dir = crdir;
      return __mach_port_mod_refs (__mach_task_self (),
                           crdir, MACH_PORT_RIGHT_SEND, +1);
    }

  const char *lastslash = strrchr (file_name, '/');

  if (lastslash != NULL)
    {
      if (lastslash == file_name)
      {
        /* "/foobar" => crdir + "foobar".  */
        *name = (char *) file_name + 1;
        return (*use_init_port) (INIT_PORT_CRDIR, &addref);
      }
      else
      {
        /* "/dir1/dir2/.../file".  */
        char dirname[lastslash - file_name + 1];
        memcpy (dirname, file_name, lastslash - file_name);
        dirname[lastslash - file_name] = '\0';
        *name = (char *) lastslash + 1;
        return
          __hurd_file_name_lookup (use_init_port, get_dtable_port, lookup,
                             dirname, 0, 0, dir);
      }
    }
  else if (file_name[0] == '\0')
    return ENOENT;
  else
    {
      /* "foobar" => cwdir + "foobar".  */
      *name = (char *) file_name;
      return (*use_init_port) (INIT_PORT_CWDIR, &addref);
    }
}
weak_alias (__hurd_file_name_split, hurd_file_name_split)

/* This is the same as hurd_file_name_split, except that it ignores
   trailing slashes (so *NAME is never "").  */
error_t
__hurd_directory_name_split (error_t (*use_init_port)
                       (int which, error_t (*operate) (file_t)),
                       file_t (*get_dtable_port) (int fd),
                       error_t (*lookup)
                       (file_t dir, char *name, int flags, mode_t mode,
                        retry_type *do_retry, string_t retry_name,
                        mach_port_t *result),
                       const char *file_name,
                       file_t *dir, char **name)
{
  error_t addref (file_t crdir)
    {
      *dir = crdir;
      return __mach_port_mod_refs (__mach_task_self (),
                           crdir, MACH_PORT_RIGHT_SEND, +1);
    }

  const char *lastslash = strrchr (file_name, '/');

  if (lastslash != NULL && lastslash[1] == '\0')
    {
      /* Trailing slash doesn't count.  Look back further.  */

      /* Back up over all trailing slashes.  */
      while (lastslash > file_name && *lastslash == '/')
      --lastslash;

      /* Find the last one earlier in the string, before the trailing ones.  */
#if __GLIBC__ > 2 || __GLIBC_MINOR__ >= 2
      lastslash = __memrchr (file_name, '/', lastslash - file_name);
#else
      /* Keep backing up, looking for a slash.  */
      do
      if (lastslash == file_name)
        {
          /* Hit the start with no slash.  */
          lastslash = NULL;
          break;
        }
      while (*lastslash-- != '/');
#endif
    }

  if (lastslash != NULL)
    {
      if (lastslash == file_name)
      {
        /* "/foobar" => crdir + "foobar".  */
        *name = (char *) file_name + 1;
        return (*use_init_port) (INIT_PORT_CRDIR, &addref);
      }
      else
      {
        /* "/dir1/dir2/.../file".  */
        char dirname[lastslash - file_name + 1];
        memcpy (dirname, file_name, lastslash - file_name);
        dirname[lastslash - file_name] = '\0';
        *name = (char *) lastslash + 1;
        return
          __hurd_file_name_lookup (use_init_port, get_dtable_port, lookup,
                             dirname, 0, 0, dir);
      }
    }
  else if (file_name[0] == '\0')
    return ENOENT;
  else
    {
      /* "foobar" => cwdir + "foobar".  */
      *name = (char *) file_name;
      return (*use_init_port) (INIT_PORT_CWDIR, &addref);
    }
}
weak_alias (__hurd_directory_name_split, hurd_directory_name_split)


file_t
__file_name_lookup (const char *file_name, int flags, mode_t mode)
{
  error_t err;
  file_t result;

  err = __hurd_file_name_lookup (&_hurd_ports_use, &__getdport, 0,
                         file_name, flags, mode & ~_hurd_umask,
                         &result);

  return err ? (__hurd_fail (err), MACH_PORT_NULL) : result;
}
weak_alias (__file_name_lookup, file_name_lookup)


file_t
__file_name_split (const char *file_name, char **name)
{
  error_t err;
  file_t result;

  err = __hurd_file_name_split (&_hurd_ports_use, &__getdport, 0,
                        file_name, &result, name);

  return err ? (__hurd_fail (err), MACH_PORT_NULL) : result;
}
weak_alias (__file_name_split, file_name_split)

file_t
__directory_name_split (const char *directory_name, char **name)
{
  error_t err;
  file_t result;

  err = __hurd_directory_name_split (&_hurd_ports_use, &__getdport, 0,
                             directory_name, &result, name);

  return err ? (__hurd_fail (err), MACH_PORT_NULL) : result;
}
weak_alias (__directory_name_split, directory_name_split)


file_t
__file_name_lookup_under (file_t startdir,
                    const char *file_name, int flags, mode_t mode)
{
  error_t err;
  file_t result;

  error_t use_init_port (int which, error_t (*operate) (mach_port_t))
    {
      return (which == INIT_PORT_CWDIR ? (*operate) (startdir) :
            _hurd_ports_use (which, operate));
    }

  err = __hurd_file_name_lookup (&use_init_port, &__getdport, 0,
                         file_name, flags, mode & ~_hurd_umask,
                         &result);

  return err ? (__hurd_fail (err), MACH_PORT_NULL) : result;
}
weak_alias (__file_name_lookup_under, file_name_lookup_under)

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