2.5-18.1

sysdeps/unix/sysv/linux/openat.c

@@ -0,0 +1,175 @@
+/* Copyright (C) 2005, 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 <errno.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <kernel-features.h>
+#include <sysdep-cancel.h>
+#include <not-cancel.h>
+
+
+#ifndef OPENAT
+# define OPENAT openat
+
+# ifndef __ASSUME_ATFCTS
+/* Set errno after a failed call.  If BUF is not null,
+   it is a /proc/self/fd/ path name we just tried to use.  */
+void
+attribute_hidden
+__atfct_seterrno (int errval, int fd, const char *buf)
+{
+  if (buf != NULL)
+    {
+      struct stat64 st;
+
+      if (errval == ENOTDIR || errval == ENOENT)
+	{
+	  /* This can mean either the file descriptor is invalid or
+	     /proc is not mounted.  */
+	  if (__fxstat64 (_STAT_VER, fd, &st) != 0)
+	    /* errno is already set correctly.  */
+	    return;
+
+	  /* If /proc is not mounted there is nothing we can do.  */
+	  if ((errval != ENOTDIR || S_ISDIR (st.st_mode))
+	      && (__xstat64 (_STAT_VER, "/proc/self/fd", &st) != 0
+		  || !S_ISDIR (st.st_mode)))
+	    errval = ENOSYS;
+	}
+    }
+
+  __set_errno (errval);
+}
+
+int __have_atfcts;
+# endif
+#endif
+
+
+#define OPENAT_NOT_CANCEL CONCAT (OPENAT)
+#define CONCAT(name) CONCAT2 (name)
+#define CONCAT2(name) __##name##_nocancel
+
+
+int
+OPENAT_NOT_CANCEL (fd, file, oflag, mode)
+     int fd;
+     const char *file;
+     int oflag;
+     mode_t mode;
+{
+
+  /* We have to add the O_LARGEFILE flag for openat64.  */
+#ifdef MORE_OFLAGS
+  oflag |= MORE_OFLAGS;
+#endif
+
+  INTERNAL_SYSCALL_DECL (err);
+  int res;
+
+#ifdef __NR_openat
+# ifndef __ASSUME_ATFCTS
+  if (__have_atfcts >= 0)
+# endif
+    {
+      res = INLINE_SYSCALL (openat, 4, fd, file, oflag, mode);
+
+# ifndef __ASSUME_ATFCTS
+      if (res == -1 && errno == ENOSYS)
+	__have_atfcts = -1;
+      else
+# endif
+	return res;
+    }
+#endif
+
+#ifndef __ASSUME_ATFCTS
+  char *buf = NULL;
+
+  if (fd != AT_FDCWD && file[0] != '/')
+    {
+      size_t filelen = strlen (file);
+      static const char procfd[] = "/proc/self/fd/%d/%s";
+      /* Buffer for the path 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.   A bit of overhead
+	 due to the format elements compensates for possible negative
+	 numbers.  */
+      size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
+      buf = alloca (buflen);
+
+      /* Note: snprintf cannot be canceled.  */
+      __snprintf (buf, buflen, procfd, fd, file);
+      file = buf;
+    }
+
+  res = INTERNAL_SYSCALL (open, err, 3, file, oflag, mode);
+
+  if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (res, err), 0))
+    {
+      __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (res, err), fd, buf);
+      res = -1;
+    }
+
+  return res;
+#endif
+}
+
+#define UNDERIZE(name) UNDERIZE_1 (name)
+#define UNDERIZE_1(name) __##name
+#define __OPENAT UNDERIZE (OPENAT)
+
+
+/* Open FILE with access OFLAG.  Interpret relative paths relative to
+   the directory associated with FD.  If OFLAG includes O_CREAT, a
+   third argument is the file protection.  */
+int
+__OPENAT (fd, file, oflag)
+     int fd;
+     const char *file;
+     int oflag;
+{
+  mode_t mode = 0;
+  if (oflag & O_CREAT)
+    {
+      va_list arg;
+      va_start (arg, oflag);
+      mode = va_arg (arg, mode_t);
+      va_end (arg);
+    }
+
+  if (SINGLE_THREAD_P)
+    return OPENAT_NOT_CANCEL (fd, file, oflag, mode);
+
+  int oldtype = LIBC_CANCEL_ASYNC ();
+
+  int res = OPENAT_NOT_CANCEL (fd, file, oflag, mode);
+
+  LIBC_CANCEL_RESET (oldtype);
+
+  return res;
+}
+libc_hidden_def (__OPENAT)
+weak_alias (__OPENAT, OPENAT)