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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /sysdeps/mach/hurd/readlink.c
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initial import
Diffstat (limited to 'sysdeps/mach/hurd/readlink.c')
-rw-r--r--sysdeps/mach/hurd/readlink.c76
1 files changed, 76 insertions, 0 deletions
diff --git a/sysdeps/mach/hurd/readlink.c b/sysdeps/mach/hurd/readlink.c
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+++ b/sysdeps/mach/hurd/readlink.c
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+/* Copyright (C) 1991, 1992, 1993, 1994, 1995 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 Library General Public License as
+published by the Free Software Foundation; either version 2 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <unistd.h>
+#include <hurd.h>
+#include <hurd/paths.h>
+#include <fcntl.h>
+#include <string.h>
+
+/* Read the contents of the symbolic link FILE_NAME into no more than
+   LEN bytes of BUF.  The contents are not null-terminated.
+   Returns the number of characters read, or -1 for errors.  */
+ssize_t
+DEFUN(__readlink, (file_name, buf, len),
+      CONST char *file_name AND char *buf AND size_t len)
+{
+  error_t err;
+  file_t file;
+  char mybuf[2048], *transp = mybuf;
+  mach_msg_type_number_t translen = sizeof (mybuf);
+
+  file = __file_name_lookup (file_name, O_NOTRANS, 0);
+  if (file == MACH_PORT_NULL)
+    return -1;
+
+  err = __file_get_translator (file, &transp, &translen);
+  __mach_port_deallocate (__mach_task_self (), file);
+
+  if (err)
+    return __hurd_fail (err);
+
+  if (translen < sizeof (_HURD_SYMLINK) ||
+      memcmp (transp, _HURD_SYMLINK, sizeof (_HURD_SYMLINK)))
+    /* The file is not actually a symlink.  */
+    err = EINVAL;
+  else
+    {
+      /* This is a symlink; its translator is "/hurd/symlink\0target\0".  */
+      if (len >= translen - sizeof (_HURD_SYMLINK))
+	{
+	  len = translen - sizeof (_HURD_SYMLINK);
+	  if (transp[translen - 1] == '\0')
+	    /* Remove the null terminator.  */
+	    --len;
+	}
+      if (buf == NULL)
+	/* This call is just to find out how large a buffer is required.  */
+	len = translen - sizeof (_HURD_SYMLINK) - 1;
+      else
+	/* Copy into the user's buffer.  */
+	memcpy (buf, transp + sizeof (_HURD_SYMLINK), len);
+    }
+
+  if (transp != mybuf)
+    __vm_deallocate (__mach_task_self (), (vm_address_t) transp, translen);
+
+  return err ? __hurd_fail (err) : len;
+}
+
+weak_alias (__readlink, readlink)