1 files changed, 130 insertions, 0 deletions
diff --git a/sysdeps/mach/hurd/brk.c b/sysdeps/mach/hurd/brk.c
new file mode 100644
index 0000000000..a96286b2d9
--- /dev/null
+++ b/sysdeps/mach/hurd/brk.c
@@ -0,0 +1,130 @@
+/* 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 <errno.h>
+#include <hurd.h>
+#include <hurd/resource.h>
+#include <cthreads.h>		/* For `struct mutex'.  */
+
+
+/* Initial maximum size of the data segment (32MB, which is arbitrary).  */
+#define	DATA_SIZE	(32 * 1024 * 1024)
+
+
+/* Up to the page including this address is allocated from the kernel.
+   This address is the data resource limit.  */
+vm_address_t _hurd_data_end;
+
+/* Up to this address is actually available to the user.
+   Pages beyond the one containing this address allow no access.  */
+vm_address_t _hurd_brk;
+
+struct mutex _hurd_brk_lock;
+
+extern int __data_start, _end;
+
+
+/* Set the end of the process's data space to INADDR.
+   Return 0 if successful, -1 if not.  */
+int
+DEFUN(__brk, (inaddr), PTR inaddr)
+{
+  int ret;
+  HURD_CRITICAL_BEGIN;
+  __mutex_lock (&_hurd_brk_lock);
+  ret = _hurd_set_brk ((vm_address_t) inaddr);
+  __mutex_unlock (&_hurd_brk_lock);
+  HURD_CRITICAL_END;
+  return ret;
+}
+weak_alias (__brk, brk)
+
+
+int
+_hurd_set_brk (vm_address_t addr)
+{
+  error_t err;
+  vm_address_t pagend = round_page (addr);
+  vm_address_t pagebrk = round_page (_hurd_brk);
+  long int rlimit;
+
+  if (pagend <= pagebrk)
+    {
+      if (pagend < pagebrk)
+	/* Make that memory inaccessible.  */
+	__vm_protect (__mach_task_self (), pagend, pagebrk - pagend,
+		      0, VM_PROT_NONE);
+      _hurd_brk = addr;
+      return 0;
+    }
+
+  __mutex_lock (&_hurd_rlimit_lock);
+  rlimit = _hurd_rlimits[RLIMIT_DATA].rlim_cur;
+  __mutex_unlock (&_hurd_rlimit_lock);
+
+  if (addr - (vm_address_t) &__data_start > rlimit)
+    {
+      /* Need to increase the resource limit.  */
+      errno = ENOMEM;
+      return -1;
+    }
+
+  /* Make the memory accessible.  */
+  if (err = __vm_protect (__mach_task_self (), pagebrk, pagend - pagebrk,
+			  0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE))
+    {
+      errno = err;
+      return -1;
+    }
+
+  _hurd_brk = addr;
+  return 0;
+}
+
+static void
+init_brk (void)
+{
+  vm_address_t pagend;
+
+  __mutex_init (&_hurd_brk_lock);
+
+  /* If _hurd_brk is already set, don't change it.  The assumption is that
+     it was set in a previous run before something like Emacs's unexec was
+     called and dumped all the data up to the break at that point.  */
+  if (_hurd_brk == 0)
+    _hurd_brk = (vm_address_t) &_end;
+
+  pagend = round_page (_hurd_brk);
+
+  _hurd_data_end = (vm_address_t) &__data_start + DATA_SIZE;
+
+  if (pagend < _hurd_data_end)
+    {
+      /* We use vm_map to allocate and change permissions atomically.  */
+      if (__vm_map (__mach_task_self (), &pagend, _hurd_data_end - pagend,
+		    0, 0, MACH_PORT_NULL, 0, 0,
+		    0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE,
+		    VM_INHERIT_COPY))
+	/* Couldn't allocate the memory.  The break will be very short.  */
+	_hurd_data_end = pagend;
+    }
+
+  (void) &init_brk;		/* Avoid ``defined but not used'' warning.  */
+}
+text_set_element (_hurd_preinit_hook, init_brk);