path: root/src/xattrs.c

/* Create a tar archive.

   Copyright (C) 2006 Free Software Foundation, Inc.

   Written by James Antill, on 2006-07-27.

   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 2, 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, write to the Free Software Foundation, Inc.,
   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

#include <system.h>

#include <quotearg.h>

#include "common.h"


#ifndef HAVE_SELINUX_SELINUX_H
# undef HAVE_LIBSELINUX
#endif

#ifndef HAVE_ATTR_XATTR_H
# undef HAVE_XATTRS
#endif

#ifndef HAVE_SYS_ACL_H
# undef HAVE_LIBACL
#endif

#ifdef HAVE_SELINUX_SELINUX_H
# include <selinux/selinux.h>
#endif

#ifdef HAVE_ATTR_XATTR_H
# include <attr/xattr.h>
#endif

#ifdef HAVE_SYS_ACL_H
# include <sys/acl.h>
#endif


#if 0 /* unused by xattr's atm. */
static void xattrs__fd_get(struct tar_stat_info *st,
                           char const *file_name, int fd, const char *attr,
                           char **ret_ptr, size_t *ret_len)
{
#ifdef HAVE_XATTRS
  static ssize_t asz = 1024;
  ssize_t ret = 0;
  static char *val = NULL;

  if (!val) val = xmalloc (asz);

  while (((ret = fgetxattr (fd, attr, val, asz)) == -1) &&
         (errno == ERANGE))
    {
      asz <<= 1;
      val = xrealloc (val, asz);
    }

  if (ret != -1)
    {
      *ret_ptr = xmemdup (val, ret);
      *ret_len = ret;
    }
  else if (errno != ENOATTR)
    call_arg_warn ("fgetxattr", file_name);
#endif
}
#endif

static void xattrs__acls_get_a(struct tar_stat_info *st,
                               char const *file_name, int fd,
                               char **ret_ptr, size_t *ret_len)
{ /* "system.posix_acl_access" */
#ifdef HAVE_LIBACL
  char *val = NULL;
  size_t len;
  acl_t acl;

  if (fd != -1)
  {
    if ((acl = acl_get_fd (fd)) == (acl_t)NULL)
    {
      if (errno != ENOTSUP)
        call_arg_warn ("acl_get_fd", file_name);
      return;
    }
  }
  else if ((acl = acl_get_file (file_name, ACL_TYPE_ACCESS)) == (acl_t)NULL)
  {
    if (errno != ENOTSUP)
      call_arg_warn ("acl_get_file", file_name);
    return;
  }

  val = acl_to_text(acl, &len);
  acl_free (acl);

  if (val == NULL)
  {
    call_arg_warn ("acl_to_text", file_name);
    return;
  }

  *ret_ptr = xstrndup (val, len);
  *ret_len = len;

  acl_free (val);
#endif
}

static void xattrs__acls_get_d(struct tar_stat_info *st,
                               char const *file_name,
                               char **ret_ptr, size_t *ret_len)
{ /* "system.posix_acl_default" */
#ifdef HAVE_LIBACL
  char *val = NULL;
  size_t len;
  acl_t acl;

  if ((acl = acl_get_file (file_name, ACL_TYPE_DEFAULT)) == (acl_t)NULL)
  {
    if (errno != ENOTSUP)
      call_arg_warn ("acl_get_file", file_name);
    return;
  }

  val = acl_to_text(acl, &len);
  acl_free (acl);

  if (val == NULL)
  {
    call_arg_warn ("acl_to_text", file_name);
    return;
  }

  *ret_ptr = xstrndup (val, len);
  *ret_len = len;

  acl_free (val);
#endif
}

void xattrs_acls_get(struct tar_stat_info *st, char const *file_name, int fd,
                     int xisfile)
{
  if (acls_option > 0)
    {
#ifndef HAVE_LIBACL
      static int done = 0;
      if (!done)
          WARN ((0, 0, _("ACL support requested, but not available")));
      done = 1;
#endif
      xattrs__acls_get_a (st, file_name, fd,
                          &st->acls_a_ptr, &st->acls_a_len);
      if (!xisfile)
        xattrs__acls_get_d (st, file_name,
                            &st->acls_d_ptr, &st->acls_d_len);
    }
}

void xattrs_selinux_get(struct tar_stat_info *st, char const *file_name, int fd)
{
  if (selinux_context_option > 0)
  {
#ifndef HAVE_LIBSELINUX
      static int done = 0;
      if (!done)
          WARN ((0, 0, _("SELinux support requested, but not available")));
      done = 1;
#else
    if (fd == -1)
    {
      if ((lgetfilecon (file_name, &st->cntx_name) == -1) && (errno != ENOTSUP) && (errno != ENODATA))
        call_arg_warn ("lgetfilecon", file_name);
    }
    else if ((fgetfilecon (fd, &st->cntx_name) == -1) && (errno != ENOTSUP) && (errno != ENODATA))
      call_arg_warn ("fgetfilecon", file_name);
#endif
  }
}

void xattrs_xattrs_get(struct tar_stat_info *st, char const *file_name, int fd)
{
  if (xattrs_option > 0)
    { /* get all xattrs ... this include security.* and system.* if
         available. We filter them here, but we have to filter them
         in xattrs_xattrs_set() anyway.
      */
      static ssize_t xsz = 1024;
      static char *xatrs = NULL;
      ssize_t xret = -1;

#ifndef HAVE_XATTRS
      static int done = 0;
      if ((xattrs_option > 0) && !done)
          WARN ((0, 0, _("Xattr support requested, but not available")));
      done = 1;
#else

      if (!xatrs) xatrs = xmalloc (xsz);

      while (((fd == -1) ?
              ((xret = listxattr (file_name, xatrs, xsz)) == -1) :
              ((xret = flistxattr (fd, xatrs, xsz)) == -1)) &&
             (errno == ERANGE))
        {
          xsz <<= 1;
          xatrs = xrealloc (xatrs, xsz);
        }

      if (xret == -1)
        call_arg_warn ((fd == -1) ? "listxattrs" : "flistxattrs", file_name);
      else
        {
          const char *attr = xatrs;
          static ssize_t asz = 1024;
          static char *val = NULL;

          if (!val) val = xmalloc (asz);

          while (xret > 0)
            {
              size_t len = strlen (attr);
              ssize_t aret = 0;

//              if (strncmp (attr, "user.", strlen("user.")) &&
//                  strncmp (attr, "trusted.", strlen("trusted.")))
//                goto next_attr; /* only store normal xattrs */

              while (((fd == -1) ?
                      ((aret = getxattr (file_name, attr, val, asz)) == -1) :
                      ((aret = fgetxattr (fd, attr, val, asz)) == -1)) &&
                     (errno == ERANGE))
                {
                  asz <<= 1;
                  val = xrealloc (val, asz);
                }

              if (aret != -1)
                xheader_xattr_add (st, attr, val, aret);
              else if (errno != ENOATTR)
                call_arg_warn ("fgetxattr", file_name);

             next_attr:
              attr += len + 1;
              xret -= len + 1;
            }
        }
#endif
    }
}

static void xattrs__fd_set(struct tar_stat_info const *st,
                           char const *file_name, char typeflag,
                           const char *attr,
                           const char *ptr, size_t len)
{
#ifdef HAVE_XATTRS
  if (ptr)
    {
      const char *sysname = "setxattr";
      int ret = -1;

      if (typeflag != SYMTYPE)
        ret = setxattr (file_name, attr, ptr, len, 0);
      else
        {
          sysname = "lsetxattr";
          ret = lsetxattr (file_name, attr, ptr, len, 0);
        }

      if ((ret == -1) && (errno == EPERM))
        call_arg_warn(sysname, file_name);
      else if ((ret == -1) && (errno != EOPNOTSUPP))
        call_arg_error(sysname, file_name);
    }
#endif
}

/* convert unix permissions into an ACL ... needed due to "default" ACLs */
#ifdef HAVE_LIBACL
static acl_t perms2acl(int perms)
{
  char val[] = "user::---,group::---,other::---";
  /*            0123456789 123456789 123456789 123456789 */

   /* user */
  if (perms & 0400) val[ 6] = 'r';
  if (perms & 0200) val[ 7] = 'w';
  if (perms & 0100) val[ 8] = 'x';

  /* group */
  if (perms & 0040) val[17] = 'r';
  if (perms & 0020) val[18] = 'w';
  if (perms & 0010) val[19] = 'x';

  /* other */
  if (perms & 0004) val[28] = 'r';
  if (perms & 0002) val[29] = 'w';
  if (perms & 0001) val[30] = 'x';

  return (acl_from_text (val));
}
#endif

static char *skip_to_ext_fields(char *ptr)
{
  ptr += strcspn(ptr, ":,\n"); /* skip tag name. Ie. user/group/default/mask */

  if (*ptr != ':')
    return (ptr); /* error? no user/group field */
  ++ptr;

  ptr += strcspn(ptr, ":,\n"); /* skip user/group name */

  if (*ptr != ':')
    return (ptr); /* error? no perms field */
  ++ptr;

  ptr += strcspn(ptr, ":,\n"); /* skip perms */

  if (*ptr != ':')
    return (ptr); /* no extra fields */

  return (ptr);
}

/* The POSIX draft allows extra fields after the three main ones. Star
   uses this to add a fourth field for user/group which is the numeric ID.
   We just skip all extra fields atm. */
static const char *fixup_extra_acl_fields(const char *ptr)
{
  char *src = (char *)ptr;
  char *dst = (char *)ptr;

  while (*src)
  {
    const char *old = src;
    size_t len = 0;

    src = skip_to_ext_fields(src);
    len = src - old;
    if (old != dst) memmove(dst, old, len);
    dst += len;

    if (*src == ':') /* We have extra fields, skip them all */
      src += strcspn(src, "\n,");

    if ((*src == '\n') || (*src == ','))
      *dst++ = *src++; /* also done when dst == src, but that's ok */
  }
  if (src != dst)
    *dst = 0;

  return ptr;
}

static void xattrs__acls_set(struct tar_stat_info const *st,
                             char const *file_name, int type,
                             const char *ptr, size_t len)
{ /* "system.posix_acl_access" */
#ifdef HAVE_LIBACL
  acl_t acl;

  if (ptr)
    {
      /* assert (strlen (ptr) == len); */
      ptr = fixup_extra_acl_fields(ptr);

      acl = acl_from_text (ptr);
      acls_option = 1;
    }
  else if (acls_option > 0)
    acl = perms2acl (st->stat.st_mode);
  else
    return; /* don't call acl functions unless we first hit an ACL, or
               --acls was passed explicitly */

  if (acl == (acl_t)NULL)
    {
      call_arg_warn ("acl_from_text", file_name);
      return;
    }

  if (acl_set_file (file_name, type, acl) == -1)
    {
      if (errno != ENOTSUP)
        call_arg_warn ("acl_set_file", file_name);
    }
  acl_free (acl);
#endif
}

void xattrs_acls_set(struct tar_stat_info const *st,
                     char const *file_name, char typeflag)
{
  if ((acls_option >= 0) && (typeflag != SYMTYPE))
    {
#ifndef HAVE_LIBACL
      static int done = 0;
      if (!done)
        WARN ((0, 0, _("ACL support requested, but not available")));
      done = 1;
#else
      xattrs__acls_set (st, file_name, ACL_TYPE_ACCESS,
                        st->acls_a_ptr, st->acls_a_len);
      if (S_ISDIR (st->stat.st_mode))
        xattrs__acls_set (st, file_name, ACL_TYPE_DEFAULT,
                          st->acls_d_ptr, st->acls_d_len);
#endif
    }
}

void xattrs_selinux_set(struct tar_stat_info const *st,
                        char const *file_name, char typeflag)
{
  if ((selinux_context_option >= 0) && st->cntx_name)
    {
      const char *sysname = "setfilecon";
      int ret = -1;

#ifndef HAVE_LIBSELINUX
      static int done = 0;
      if (!done)
          WARN ((0, 0, _("SELinux support requested, but not available")));
      done = 1;
#else
      if (typeflag != SYMTYPE)
        ret = setfilecon (file_name, st->cntx_name);
      else
        {
          sysname = "lsetfilecon";
          ret = lsetfilecon (file_name, st->cntx_name);
        }

      /* do not print warnings when SELinux is disabled */
      if ((ret == -1) && (errno != EPERM) && (errno != ENOTSUP))
        call_arg_error(sysname, file_name);
#endif
    }
}

void xattrs_xattrs_set(struct tar_stat_info const *st,
                       char const *file_name, char typeflag)
{
  if ((xattrs_option >= 0) && st->xattr_map_size)
    {
      size_t scan = 0;

#ifndef HAVE_XATTRS
      static int done = 0;
      if (!done)
          WARN ((0, 0, _("Xattr support requested, but not available")));
      done = 1;
#else
      while (scan < st->xattr_map_size)
        {
          char *keyword = st->xattr_map[scan].xkey;

          /* assert (!memcpy (keyword, "SCHILY.xattr.", strlen("SCHILY.xattr."))); */
          keyword += strlen("SCHILY.xattr.");

//          if (strncmp (keyword, "user.", strlen("user.")) &&
//              strncmp (keyword, "trusted.", strlen("trusted.")))
//            continue; /* don't try and set anything but normal xattrs */

          /* should we ignore trusted.* EPERM errors when not root ? */
          xattrs__fd_set (st, file_name, typeflag, keyword,
                          st->xattr_map[scan].xval_ptr,
                          st->xattr_map[scan].xval_len);

          ++scan;
        }
#endif
    }
}