Libc-262.tar.gz

[apple/libc.git] / mach / sbrk.c

diff --git a/mach/sbrk.c b/mach/sbrk.c
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+/*
+ * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * The contents of this file constitute Original Code as defined in and
+ * are subject to the Apple Public Source License Version 1.1 (the
+ * "License").  You may not use this file except in compliance with the
+ * License.  Please obtain a copy of the License at
+ * http://www.apple.com/publicsource and read it before using this file.
+ * 
+ * This Original Code and all software distributed under the License are
+ * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
+ * License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+/*
+ *     File:   sbrk.c
+ *
+ *     Unix compatibility for sbrk system call.
+ *
+ * HISTORY
+ * 09-Mar-90  Gregg Kellogg (gk) at NeXT.
+ *     include <kern/mach_interface.h> instead of <kern/mach.h>
+ *
+ * 14-Feb-89  Avadis Tevanian (avie) at NeXT.
+ *     Total rewrite using a fixed area of VM from break region.
+ */
+
+#include <mach/mach.h>         /* for vm_allocate, vm_offset_t */
+#include <mach/vm_statistics.h>
+#include <sys/types.h>         /* for caddr_t */
+
+static int sbrk_needs_init = TRUE;
+static vm_size_t sbrk_region_size = 4*1024*1024; /* Well, what should it be? */
+static vm_address_t sbrk_curbrk;
+
+caddr_t sbrk(size)
+       int     size;
+{
+       vm_offset_t     addr;
+       kern_return_t   ret;
+       caddr_t         ocurbrk;
+       extern int      end;
+
+       if (sbrk_needs_init) {
+               sbrk_needs_init = FALSE;
+               /*
+                *      Allocate a big region to simulate break region.
+                */
+               ret =  vm_allocate(mach_task_self(), &sbrk_curbrk, sbrk_region_size,
+                                 VM_MAKE_TAG(VM_MEMORY_SBRK)|TRUE);
+               if (ret != KERN_SUCCESS)
+                       return((caddr_t)-1);
+       }
+       
+       if (size <= 0)
+               return((caddr_t)sbrk_curbrk);
+       sbrk_curbrk += size;
+       sbrk_region_size -= size;
+       if (sbrk_region_size < 0)
+               return((caddr_t)-1);
+       return((caddr_t)(sbrk_curbrk - size));
+}
+
+caddr_t brk(x)
+       caddr_t x;
+{
+       return((caddr_t)-1);
+}
+