[Glibc-bsd-commits] r2564 - trunk/glibc-ports/kfreebsd

[Aurelien Jarno]

Author: aurel32
Date: 2009-06-02 10:20:40 +0000 (Tue, 02 Jun 2009)
New Revision: 2564

Added:
   trunk/glibc-ports/kfreebsd/readonly-area.c
Log:
Add kFreeBSD version of __readonly_area()


Added: trunk/glibc-ports/kfreebsd/readonly-area.c
===================================================================
--- trunk/glibc-ports/kfreebsd/readonly-area.c	                        (rev 0)
+++ trunk/glibc-ports/kfreebsd/readonly-area.c	2009-06-02 10:20:40 UTC (rev 2564)
@@ -0,0 +1,96 @@
+/* Copyright (C) 2004, 2005, 2009 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 <stdint.h>
+#include <stdio.h>
+#include <stdio_ext.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/sysctl.h>
+#include <sys/user.h>
+#include "libio/libioP.h"
+
+/* Return 1 if the whole area PTR .. PTR+SIZE is not writable.
+   Return -1 if it is writable.  */
+
+int
+__readonly_area (const char *ptr, size_t size)
+{
+  const void *ptr_end = ptr + size;
+
+  int mib[4];
+  size_t kve_len = 0;
+  char *kve_buf, *kve_bufp;
+
+  mib[0] = CTL_KERN;
+  mib[1] = KERN_PROC;
+  mib[2] = KERN_PROC_VMMAP;
+  mib[3] = __getpid ();
+
+  if (sysctl (mib, 4, NULL, &kve_len, NULL, 0) != 0)
+    {
+      __set_errno (ENOSYS);
+      return 1;
+    }
+
+  kve_buf = alloca (kve_len);
+  if (sysctl (mib, 4, kve_buf, &kve_len, NULL, 0) != 0)
+    {
+      __set_errno (ENOSYS);
+      return 1;
+    }
+
+  kve_bufp = kve_buf;
+  while (kve_bufp < kve_buf + kve_len)
+    {
+      struct kinfo_vmentry *kve = (struct kinfo_vmentry *) (uintptr_t) kve_bufp;
+      kve_bufp += kve->kve_structsize;
+
+      uintptr_t from = kve->kve_start;
+      uintptr_t to = kve->kve_end;
+
+      if (from < (uintptr_t) ptr_end && to > (uintptr_t) ptr)
+	{
+	  /* Found an entry that at least partially covers the area.  */
+	  if (!(kve->kve_protection & KVME_PROT_READ)
+	      || (kve->kve_protection & KVME_PROT_WRITE))
+	    break;
+
+	  if (from <= (uintptr_t) ptr && to >= (uintptr_t) ptr_end)
+	    {
+	      size = 0;
+	      break;
+	    }
+	  else if (from <= (uintptr_t) ptr)
+	    size -= to - (uintptr_t) ptr;
+	  else if (to >= (uintptr_t) ptr_end)
+	    size -= (uintptr_t) ptr_end - from;
+	  else
+	    size -= to - from;
+
+	  if (!size)
+	    break;
+	}
+    }
+
+  /* If the whole area between ptr and ptr_end is covered by read-only
+     VMAs, return 1.  Otherwise return -1.  */
+  return size == 0 ? 1 : -1;
+}