X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fopenat-priv.h;h=fd0adc1855f9622f9942f974e67e7f5d30cf5690;hb=a1c8d3d65945c9d7b1ad9ac02e980baa0394e30d;hp=2b4780eecf113ebb0e298ea3eee4d42c61949439;hpb=14bf04a59fbfa9ae7a9b55f7885ed96a5f0341ac;p=gnulib.git

diff --git a/lib/openat-priv.h b/lib/openat-priv.h
index 2b4780eec..fd0adc185 100644
--- a/lib/openat-priv.h
+++ b/lib/openat-priv.h
@@ -1,10 +1,11 @@
-/* macros used by openat-like functions
-   Copyright (C) 2005 Free Software Foundation, Inc.
+/* Internals for openat-like functions.
 
-   This program is free software; you can redistribute it and/or modify
+   Copyright (C) 2005-2006, 2009-2012 Free Software Foundation, Inc.
+
+   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.
+   the Free Software Foundation; either version 3 of the License, 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
@@ -12,41 +13,52 @@
    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.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 /* written by Jim Meyering */
 
-#include <stdio.h>
-#include <string.h>
-#include "alloca.h"
-#include "intprops.h"
-
-/* Set PROC_FD_FILENAME to the expansion of "/proc/self/fd/%d/%s" in
-   alloca'd memory, using FD and FILE, respectively for %d and %s. */
-#define BUILD_PROC_NAME(Proc_fd_filename, Fd, File)			\
-  do									\
-    {									\
-      size_t filelen = strlen (File);					\
-      static const char procfd[] = "/proc/self/fd/%d/%s";		\
-      /* Buffer for the file name we are going to use.  It consists of	\
-	 - the string /proc/self/fd/					\
-	 - the file descriptor number					\
-	 - the file name provided.					\
-	 The final NUL is included in the sizeof.			\
-	 Subtract 4 to account for %d and %s.  */			\
-      size_t buflen = sizeof (procfd) - 4 + INT_STRLEN_BOUND (Fd) + filelen; \
-      (Proc_fd_filename) = alloca (buflen);				\
-      snprintf ((Proc_fd_filename), buflen, procfd, (Fd), (File));	\
-    }									\
-  while (0)
+#ifndef _GL_HEADER_OPENAT_PRIV
+#define _GL_HEADER_OPENAT_PRIV
+
+#include <errno.h>
+#include <limits.h>
+#include <stdlib.h>
+
+/* Maximum number of bytes that it is safe to allocate as a single
+   array on the stack, and that is known as a compile-time constant.
+   The assumption is that we'll touch the array very quickly, or a
+   temporary very near the array, provoking an out-of-memory trap.  On
+   some operating systems, there is only one guard page for the stack,
+   and a page size can be as small as 4096 bytes.  Subtract 64 in the
+   hope that this will let the compiler touch a nearby temporary and
+   provoke a trap.  */
+#define SAFER_ALLOCA_MAX (4096 - 64)
+
+#define SAFER_ALLOCA(m) ((m) < SAFER_ALLOCA_MAX ? (m) : SAFER_ALLOCA_MAX)
+
+#if defined PATH_MAX
+# define OPENAT_BUFFER_SIZE SAFER_ALLOCA (PATH_MAX)
+#elif defined _XOPEN_PATH_MAX
+# define OPENAT_BUFFER_SIZE SAFER_ALLOCA (_XOPEN_PATH_MAX)
+#else
+# define OPENAT_BUFFER_SIZE SAFER_ALLOCA (1024)
+#endif
+
+char *openat_proc_name (char buf[OPENAT_BUFFER_SIZE], int fd, char const *file);
 
 /* Trying to access a BUILD_PROC_NAME file will fail on systems without
    /proc support, and even on systems *with* ProcFS support.  Return
    nonzero if the failure may be legitimate, e.g., because /proc is not
    readable, or the particular .../fd/N directory is not present.  */
-#define EXPECTED_ERRNO(Errno)			\
-  ((Errno) == ENOTDIR || (Errno) == ENOENT	\
-   || (Errno) == EPERM || (Errno) == EACCES	\
-   || (Errno) == ENOSYS /* Solaris 8 */		\
+#define EXPECTED_ERRNO(Errno)                   \
+  ((Errno) == ENOTDIR || (Errno) == ENOENT      \
+   || (Errno) == EPERM || (Errno) == EACCES     \
+   || (Errno) == ENOSYS /* Solaris 8 */         \
    || (Errno) == EOPNOTSUPP /* FreeBSD */)
+
+/* Wrapper function shared among linkat and renameat.  */
+int at_func2 (int fd1, char const *file1,
+              int fd2, char const *file2,
+              int (*func) (char const *file1, char const *file2));
+
+#endif /* _GL_HEADER_OPENAT_PRIV */