Add basic suuport for extended attributes.

* src/Makefile.am: Add xattrs.[ch]
* src/xattrs.c: New file.
* src/xattrs.h: New file.
* src/common.h (READ_LIKE_SUBCOMMAND): New define.
(selinux_context_option, acls_option, xattrs_option): New globals.
(xheader_xattr_init, xheader_xattr_free)
(xheader_xattr_copy, xheader_xattr_add): New protos.
(WARN_XATTR_WRITE): New mask.
* src/create.c (start_header): Handle xattrs pairs if in POSIX format.
(dump_file0): Handle extended attributes.
* src/extract.c (delayed_set_stat,delayed_link) <xattr_map_size>
<xattr_map>: New members.
(set_xattr): New static function.
(open_output_file): Accept an additional argument indicating
whether the file has already been created.
(set_stat,delay_set_stat)
(apply_nonancestor_delayed_set_stat)
(extract_file): Handle extended attributes.
* src/list.c (decode_header, simple_print_header): Display
extended attributes.
* src/tar.c: New options --xattrs, --no-xattrs, --xattrs-include,
--xattrs-exclude
(tar_stat_destroy): Free the xattr_map storage.
* src/tar.h (xattr_array): New struct.
(tar_stat_info) <xattr_map_size, xattr_map>: New members.
* src/warning.c: New warning control keyword "xattr-write".
* src/xheader.c (xheader_xattr_init)
(xheader_xattr_free, xheader_xattr_add)
(xheader_xattr_copy): New functions.
(struct xhdr_tab) <prefix>: New member.
(locate_handler): Permit selecting the keyword based on its
prefix.
(xheader_protected_pattern_p)
(xheader_protected_keyword_p): Likewise.
(xattr_coder, xattr_decoder): New functions.
(xhdr_tab): Reflect the changes to struct xhdr_tab.
New keyword "SCHILY.xattr".
* tests/Makefile.am: Add new tests.
* tests/testsuite.at: Likewise.
(AT_CHECK_UTIL, AT_XATTRS_UTILS_PREREQ)
(AT_CAPABILITIES_UTILS_PREREQ, AT_XATTRS_PREREQ): New defuns.
* tests/xattr01.at: New test.
* tests/xattr02.at: New test.
* tests/xattr03.at: New test.
* tests/xattr04.at: New test.
* tests/capabs_raw01.at: New test.

1 files changed, 315 insertions, 0 deletions

diff --git a/src/xattrs.c b/src/xattrs.c
new file mode 100644
index 00000000..e813d538
--- /dev/null
+++ b/src/xattrs.c
@@ -0,0 +1,315 @@
+/* Support for extended attributes.
+
+   Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 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 <fnmatch.h>
+#include <quotearg.h>
+
+#include "common.h"
+
+#include "xattr-at.h"
+
+struct xattrs_mask_map
+{
+  const char **masks;
+  int size;
+  int used;
+};
+
+/* list of fnmatch patterns */
+static struct
+{
+  /* lists of fnmatch patterns */
+  struct xattrs_mask_map incl;
+  struct xattrs_mask_map excl;
+} xattrs_setup;
+
+static void mask_map_realloc (struct xattrs_mask_map *map)
+{
+  if (map->size == 0)
+    {
+      map->size = 4;
+      map->masks = xmalloc (16 * sizeof (char *));
+      return;
+    }
+
+  if (map->size <= map->used)
+    {
+      map->size *= 2;
+      map->masks = xrealloc (map->masks, map->size * sizeof (char *));
+      return;
+    }
+}
+
+void xattrs_mask_add (const char *mask, bool incl)
+{
+  struct xattrs_mask_map *mask_map = incl ? &xattrs_setup.incl
+                                          : &xattrs_setup.excl;
+  /* ensure there is enough space */
+  mask_map_realloc (mask_map);
+  /* just assign pointers -- we silently expect that pointer "mask" is valid
+     through the whole program (pointer to argv array) */
+  mask_map->masks[mask_map->used++] = mask;
+}
+
+static void clear_mask_map (struct xattrs_mask_map *mask_map)
+{
+  if (mask_map->size)
+    free (mask_map->masks);
+}
+
+void xattrs_clear_setup ()
+{
+  clear_mask_map (&xattrs_setup.incl);
+  clear_mask_map (&xattrs_setup.excl);
+}
+
+/* get all xattrs from file given by FILE_NAME or FD (when non-zero).  This
+   includes all the user.*, security.*, system.*, etc. available domains */
+void xattrs_xattrs_get (int parentfd, char const *file_name,
+                        struct tar_stat_info *st, int fd)
+{
+  if (xattrs_option > 0)
+    {
+#ifndef HAVE_XATTRS
+      static int done = 0;
+      if (!done)
+        WARN ((0, 0, _("XATTR support is not available")));
+      done = 1;
+#else
+      static ssize_t xsz = 1024;
+      static char *xatrs = NULL;
+      ssize_t xret = -1;
+
+      if (!xatrs) xatrs = xmalloc (xsz);
+
+      while (((fd == 0) ?
+              ((xret = llistxattrat (parentfd, 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 == 0) ? "llistxattrat" : "flistxattr", 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;
+
+              /* Archive all xattrs during creation, decide at extraction time
+               * which ones are of interest/use for the target filesystem. */
+              while (((fd == 0)
+                      ? ((aret = lgetxattrat (parentfd, 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 ((fd == 0) ? "lgetxattrat"
+                                         : "fgetxattr", file_name);
+
+              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)
+{
+  if (ptr)
+    {
+      const char *sysname = "setxattrat";
+      int ret = -1;
+
+      if (typeflag != SYMTYPE)
+        ret = setxattrat (chdir_fd, file_name, attr, ptr, len, 0);
+      else
+        {
+          sysname = "lsetxattr";
+          ret = lsetxattrat (chdir_fd, file_name, attr, ptr, len, 0);
+        }
+
+      if (ret == -1)
+        WARNOPT (WARN_XATTR_WRITE, (0, errno,
+            _("%s: Cannot set '%s' extended attribute for file '%s'"),
+            sysname, attr, file_name));
+    }
+}
+
+static bool xattrs_matches_mask (const char *kw, struct xattrs_mask_map *mm)
+{
+  int i;
+
+  if (!mm->size)
+    return false;
+
+  for (i = 0; i < mm->used; i++)
+    if (fnmatch (mm->masks[i], kw, 0) == 0)
+      return true;
+
+  return false;
+}
+
+static bool xattrs_kw_included (const char *kw, bool archiving)
+{
+   if (xattrs_setup.incl.size)
+     return xattrs_matches_mask (kw, &xattrs_setup.incl);
+   else
+     {
+       if (archiving)
+         return true;
+       else
+         return strncmp (kw, "user.", strlen ("user.")) == 0;
+     }
+}
+
+static bool xattrs_kw_excluded (const char *kw, bool archiving)
+{
+  if (!xattrs_setup.excl.size)
+    return false;
+
+  return xattrs_matches_mask (kw, &xattrs_setup.excl);
+}
+
+/* Check whether the xattr with keyword KW should be discarded from list of
+   attributes that are going to be archived/excluded (set ARCHIVING=true for
+   archiving, false for excluding) */
+static bool xattrs_masked_out (const char *kw, bool archiving)
+{
+  if (!xattrs_kw_included (kw, archiving))
+    return true;
+
+  return xattrs_kw_excluded (kw, archiving);
+}
+
+void xattrs_xattrs_set (struct tar_stat_info const *st,
+                        char const *file_name, char typeflag,
+                        int later_run)
+{
+  if (xattrs_option > 0)
+    {
+#ifndef HAVE_XATTRS
+      static int done = 0;
+      if (!done)
+        WARN ((0, 0, _("XATTR support is not available")));
+      done = 1;
+#else
+      size_t scan = 0;
+
+      if (!st->xattr_map_size)
+        return;
+
+      for (; scan < st->xattr_map_size; ++scan)
+        {
+          char *keyword = st->xattr_map[scan].xkey;
+          keyword += strlen ("SCHILY.xattr.");
+
+          /* TODO: this 'later_run' workaround is temporary solution -> once
+             capabilities should become fully supported by it's API and there
+             should exist something like xattrs_capabilities_set() call.
+             For a regular files: all extended attributes are restored during
+             the first run except 'security.capability' which is restored in
+             'later_run == 1'.  */
+          if (typeflag == REGTYPE
+              && later_run == !!strcmp (keyword, "security.capability"))
+            continue;
+
+          if (xattrs_masked_out (keyword, false /* extracting */ ))
+            /* we don't want to restore this keyword */
+            continue;
+
+          xattrs__fd_set (st, file_name, typeflag, keyword,
+                          st->xattr_map[scan].xval_ptr,
+                          st->xattr_map[scan].xval_len);
+        }
+#endif
+    }
+}
+
+void xattrs_print_char (struct tar_stat_info const *st, char *output)
+{
+  int i;
+  if (verbose_option < 2)
+    {
+      *output = 0;
+      return;
+    }
+
+  if (xattrs_option > 0)
+    {
+      /* placeholders */
+      *output = ' ';
+      *(output + 1) = 0;
+    }
+
+  if (xattrs_option > 0 && st->xattr_map_size)
+    for (i = 0; i < st->xattr_map_size; ++i)
+      {
+        char *keyword = st->xattr_map[i].xkey + strlen ("SCHILY.xattr.");
+        if (xattrs_masked_out (keyword, false /* like extracting */ ))
+          continue;
+        *output = '*';
+        break;
+      }
+}
+
+void xattrs_print (struct tar_stat_info const *st)
+{
+  if (verbose_option < 3)
+    return;
+
+  /* xattrs */
+  if (xattrs_option && st->xattr_map_size)
+    {
+      int i;
+      for (i = 0; i < st->xattr_map_size; ++i)
+        {
+          char *keyword = st->xattr_map[i].xkey + strlen ("SCHILY.xattr.");
+          if (xattrs_masked_out (keyword, false /* like extracting */ ))
+            continue;
+          fprintf (stdlis, "  x: %lu %s\n",
+		   (unsigned long) st->xattr_map[i].xval_len, keyword);
+        }
+    }
+}