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/* Support for *xattr interfaces on GNU/Hurd.
Copyright (C) 2006-2020 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, see
<https://www.gnu.org/licenses/>. */
#include <hurd.h>
#include <hurd/xattr.h>
#include <string.h>
#include <sys/mman.h>
/* Right now we support only a fixed set of xattr names for Hurd features.
There are no RPC interfaces for free-form xattr names and values.
Name Value encoding
---- ----- --------
gnu.author empty if st_author==st_uid
uid_t giving st_author value
gnu.translator empty if no passive translator
translator and arguments: "/hurd/foo\0arg1\0arg2\0"
*/
error_t
_hurd_xattr_get (io_t port, const char *name, void *value, size_t *size)
{
if (strncmp (name, "gnu.", 4))
return EOPNOTSUPP;
name += 4;
if (!strcmp (name, "author"))
{
struct stat64 st;
error_t err = __io_stat (port, &st);
if (err)
return err;
if (st.st_author == st.st_uid)
*size = 0;
else if (value)
{
if (*size < sizeof st.st_author)
return ERANGE;
memcpy (value, &st.st_author, sizeof st.st_author);
}
*size = sizeof st.st_author;
return 0;
}
if (!strcmp (name, "translator"))
{
char *buf = value;
size_t bufsz = value ? *size : 0;
error_t err = __file_get_translator (port, &buf, &bufsz);
if (err)
return err;
if (value != NULL && *size < bufsz)
{
if (buf != value)
__munmap (buf, bufsz);
return -ERANGE;
}
if (buf != value && bufsz > 0)
{
if (value != NULL)
memcpy (value, buf, bufsz);
__munmap (buf, bufsz);
}
*size = bufsz;
return 0;
}
return EOPNOTSUPP;
}
error_t
_hurd_xattr_set (io_t port, const char *name, const void *value, size_t size,
int flags)
{
if (strncmp (name, "gnu.", 4))
return EOPNOTSUPP;
name += 4;
if (!strcmp (name, "author"))
switch (size)
{
default:
return EINVAL;
case 0: /* "Clear" author by setting to st_uid. */
{
struct stat64 st;
error_t err = __io_stat (port, &st);
if (err)
return err;
if (st.st_author == st.st_uid)
{
/* Nothing to do. */
if (flags & XATTR_REPLACE)
return ENODATA;
return 0;
}
if (flags & XATTR_CREATE)
return EEXIST;
return __file_chauthor (port, st.st_uid);
}
case sizeof (uid_t): /* Set the author. */
{
uid_t id;
memcpy (&id, value, sizeof id);
if (flags & (XATTR_CREATE|XATTR_REPLACE))
{
struct stat64 st;
error_t err = __io_stat (port, &st);
if (err)
return err;
if (st.st_author == st.st_uid)
{
if (flags & XATTR_REPLACE)
return ENODATA;
}
else if (flags & XATTR_CREATE)
return EEXIST;
if (st.st_author == id)
/* Nothing to do. */
return 0;
}
return __file_chauthor (port, id);
}
}
if (!strcmp (name, "translator"))
{
if (flags & XATTR_REPLACE)
{
/* Must make sure it's already there. */
char *buf = NULL;
size_t bufsz = 0;
error_t err = __file_get_translator (port, &buf, &bufsz);
if (err)
return err;
if (bufsz > 0)
{
__munmap (buf, bufsz);
return ENODATA;
}
}
return __file_set_translator (port,
FS_TRANS_SET | ((flags & XATTR_CREATE)
? FS_TRANS_EXCL : 0), 0, 0,
value, size,
MACH_PORT_NULL, MACH_MSG_TYPE_COPY_SEND);
}
return EOPNOTSUPP;
}
error_t
_hurd_xattr_remove (io_t port, const char *name)
{
return _hurd_xattr_set (port, name, NULL, 0, XATTR_REPLACE);
}
error_t
_hurd_xattr_list (io_t port, void *buffer, size_t *size)
{
size_t total = 0;
char *bufp = buffer;
inline void add (const char *name, size_t len)
{
total += len;
if (bufp != NULL && total <= *size)
bufp = __mempcpy (bufp, name, len);
}
#define add(s) add (s, sizeof s)
struct stat64 st;
error_t err = __io_stat (port, &st);
if (err)
return err;
if (st.st_author != st.st_uid)
add ("gnu.author");
if (st.st_mode & S_IPTRANS)
add ("gnu.translator");
if (buffer != NULL && total > *size)
return ERANGE;
*size = total;
return 0;
}
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