newlib/winsup/cygwin/heap.cc

168 lines
5.2 KiB
C++

/* heap.cc: Cygwin heap manager.
Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#include "winsup.h"
#include <errno.h>
#include "cygerrno.h"
#include "sigproc.h"
#include "pinfo.h"
#include "heap.h"
#include "shared_info.h"
#include "security.h"
#include "fhandler.h"
#include "path.h"
#include "dtable.h"
#include "cygheap.h"
#include "registry.h"
#include "cygwin_version.h"
#define assert(x)
static unsigned page_const;
extern "C" size_t getpagesize ();
#define MINHEAP_SIZE (4 * 1024 * 1024)
/* Initialize the heap at process start up. */
void
heap_init ()
{
/* If we're the forkee, we must allocate the heap at exactly the same place
as our parent. If not, we don't care where it ends up. */
page_const = system_info.dwPageSize;
if (!cygheap->user_heap.base)
{
cygheap->user_heap.chunk = cygwin_shared->heap_chunk_size ();
while (cygheap->user_heap.chunk >= MINHEAP_SIZE)
{
/* Initialize page mask and default heap size. Preallocate a heap
* to assure contiguous memory. */
cygheap->user_heap.ptr = cygheap->user_heap.top =
cygheap->user_heap.base =
VirtualAlloc (NULL, cygheap->user_heap.chunk, MEM_RESERVE, PAGE_NOACCESS);
if (cygheap->user_heap.base)
break;
cygheap->user_heap.chunk -= 1 * 1024 * 1024;
}
if (cygheap->user_heap.base == NULL)
api_fatal ("unable to allocate heap, heap_chunk_size %d, %E",
cygheap->user_heap.chunk);
}
else
{
DWORD chunk = cygheap->user_heap.chunk; /* allocation chunk */
/* total size commited in parent */
DWORD allocsize = (char *) cygheap->user_heap.top -
(char *) cygheap->user_heap.base;
/* round up by chunk size */
DWORD reserve_size = chunk * ((allocsize + (chunk - 1)) / chunk);
/* Loop until we've managed to reserve an adequate amount of memory. */
char *p;
MEMORY_BASIC_INFORMATION m;
(void) VirtualQuery (cygheap->user_heap.base, &m, sizeof (m));
for (;;)
{
p = (char *) VirtualAlloc (cygheap->user_heap.base, reserve_size,
MEM_RESERVE, PAGE_READWRITE);
if (p)
break;
if ((reserve_size -= page_const) <= allocsize)
break;
}
if (p == NULL)
{
system_printf ("unable to allocate heap %p, chunk %u, reserve %u, alloc %u, %E",
cygheap->user_heap.base, cygheap->user_heap.chunk,
reserve_size, allocsize);
system_printf ("base %p mem alloc base %p, state %p, size %d, %E",
cygheap->user_heap.base, m.AllocationBase, m.State, m.RegionSize);
error_start_init ("h:/gdbtest/gdb.exe < con > con"); try_to_debug ();
api_fatal ("unable to allocate heap %p, chunk %u, reserve %u, alloc %u, %E",
cygheap->user_heap.base, cygheap->user_heap.chunk,
reserve_size, allocsize);
}
if (p != cygheap->user_heap.base)
api_fatal ("heap allocated but not at %p", cygheap->user_heap.base);
if (!VirtualAlloc (cygheap->user_heap.base, allocsize, MEM_COMMIT, PAGE_READWRITE))
api_fatal ("MEM_COMMIT failed, %E");
}
debug_printf ("heap base %p, heap top %p", cygheap->user_heap.base,
cygheap->user_heap.top);
page_const--;
malloc_init ();
}
#define pround(n) (((size_t)(n) + page_const) & ~page_const)
/* FIXME: This function no longer handles "split heaps". */
extern "C" void *
sbrk (int n)
{
sigframe thisframe (mainthread);
char *newtop, *newbrk;
unsigned commitbytes, newbrksize;
if (n == 0)
return cygheap->user_heap.ptr; /* Just wanted to find current cygheap->user_heap.ptr address */
newbrk = (char *) cygheap->user_heap.ptr + n; /* Where new cygheap->user_heap.ptr will be */
newtop = (char *) pround (newbrk); /* Actual top of allocated memory -
on page boundary */
if (newtop == cygheap->user_heap.top)
goto good;
if (n < 0)
{ /* Freeing memory */
assert (newtop < cygheap->user_heap.top);
n = (char *) cygheap->user_heap.top - newtop;
if (VirtualFree (newtop, n, MEM_DECOMMIT)) /* Give it back to OS */
goto good; /* Didn't take */
else
goto err;
}
assert (newtop > cygheap->user_heap.top);
/* Need to grab more pages from the OS. If this fails it may be because
* we have used up previously reserved memory. Or, we're just plumb out
* of memory. */
commitbytes = pround (newtop - (char *) cygheap->user_heap.top);
if (VirtualAlloc (cygheap->user_heap.top, commitbytes, MEM_COMMIT, PAGE_READWRITE) != NULL)
goto good;
/* Couldn't allocate memory. Maybe we can reserve some more.
Reserve either the maximum of the standard cygwin_shared->heap_chunk_size () or the requested
amount. Then attempt to actually allocate it. */
if ((newbrksize = cygheap->user_heap.chunk) < commitbytes)
newbrksize = commitbytes;
if ((VirtualAlloc (cygheap->user_heap.top, newbrksize, MEM_RESERVE, PAGE_NOACCESS) != NULL) &&
(VirtualAlloc (cygheap->user_heap.top, commitbytes, MEM_COMMIT, PAGE_READWRITE) != NULL))
goto good;
err:
set_errno (ENOMEM);
return (void *) -1;
good:
void *oldbrk = cygheap->user_heap.ptr;
cygheap->user_heap.ptr = newbrk;
cygheap->user_heap.top = newtop;
return oldbrk;
}