2.5-18.1

hurd/xattr.c

@@ -0,0 +1,201 @@
+/* Support for *xattr interfaces on GNU/Hurd.
+   Copyright (C) 2006 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/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;
+}