* Check in Fred Fish's changes in these modules. Fred

will make ChangeLog entries for all of them.

1 files changed, 145 insertions, 0 deletions

diff --git a/gdb/mmap-sbrk.c b/gdb/mmap-sbrk.c
new file mode 100755
index 0000000..fe9c072
--- /dev/null
+++ b/gdb/mmap-sbrk.c
@@ -0,0 +1,145 @@
+/* GDB support for an sbrk-like function that uses mmap.
+   Copyright 1992 Free Software Foundation, Inc.
+   Contributed by Cygnus Support, using pieces from other GDB modules.
+
+This file is part of GDB.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program 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 General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include <stdio.h>
+#include "defs.h"
+
+#ifdef HAVE_MMAP
+
+#include <fcntl.h>
+#include <sys/mman.h>
+
+#ifdef i386
+#define MMAP_BASE ((caddr_t) 0x81000000)
+#define MMAP_PGSZ 0x00002000  /* Must be multiple of real page size */
+#else
+#define MMAP_BASE ((caddr_t) 0xC2000000)
+#define MMAP_PGSZ 0x00002000  /* Must be multiple of real page size */
+#endif
+
+#define PAGE_ALIGN(addr) (caddr_t) (((long)(addr) + MMAP_PGSZ - 1) & \
+				    ~(MMAP_PGSZ - 1))
+
+static caddr_t mbase = MMAP_BASE;	/* Current base of mmap'd region */
+static caddr_t mbreak = MMAP_BASE;	/* Current "break" address */
+static caddr_t mtop = MMAP_BASE;	/* Current top of mmap'd region */
+
+static int fd = -1;			/* Open fd for /dev/zero */
+
+
+/*  Provide a utility routine for other modules to obtain compatible
+    page alignment. */
+
+PTR
+mmap_page_align (addr)
+     PTR addr;
+{
+  return (PAGE_ALIGN (addr));
+}
+
+/*  Return the base address of the start of the mmap'd region.  Note that
+    we can find the end of the region at anytime by calling mmap_sbrk(0) */
+
+PTR
+mmap_base ()
+{
+  return (mbase);
+}
+
+/*  Works like sbrk(), but uses mmap to add to or subtract from a
+    memory region. */
+
+PTR
+mmap_sbrk (size)
+     int size;
+{
+  PTR result = NULL;
+  int minc;
+  caddr_t moveto;
+
+  if (size == 0)
+    {
+      /* Just return the current "break" value. */
+      result = mbreak;
+    }
+  else if (size < 0)
+    {
+      /* We are deallocating memory.  If the amount requested would cause
+	 us to try to deallocate back past the base of the mmap'd region
+	 then do nothing, and return NULL.  Otherwise, deallocate the
+	 memory and return the old break value. */
+      if (mbreak + size >= mbase)
+	{
+	  result = (PTR) mbreak;
+	  mbreak += size;
+	  moveto = PAGE_ALIGN (mbreak);
+	  munmap (moveto, (size_t) (mtop - moveto));
+	  mtop = moveto;
+	}
+    }
+  else
+    {
+      /* We are allocating memory.  Make sure we have an open file
+	 descriptor and then go on to get the memory. */
+      if ((fd == -1) && (fd = open ("/dev/zero", O_RDONLY)) < 0)
+	{
+	  result = NULL;
+	}
+      else if (mbreak + size > mtop)
+	{
+	  /* The request would move us past the end of the currently
+	     mapped memory, so map in enough more memory to satisfy
+	     the request. */
+	  moveto = PAGE_ALIGN (mbreak + size);
+	  if (mmap (mtop, moveto - mtop, PROT_READ | PROT_WRITE,
+		    MAP_PRIVATE | MAP_FIXED, fd, 0) == mtop)
+	    {
+	      mtop = moveto;
+	      result = (PTR) mbreak;
+	      mbreak += size;
+	    }
+	}
+      else
+	{
+	  result = (PTR) mbreak;
+	  mbreak += size;
+	}
+    }
+  return (result);
+}
+
+PTR
+mmap_remap (base, mapsize, fd, foffset)
+     PTR base;
+     long mapsize;
+     int fd;
+     long foffset;
+{
+  /* FIXME:  Quick hack, needs error checking and other attention. */
+  munmap (mbase, (size_t) (mtop - mbase));
+  mbase = base;
+  mtop = mbase + mapsize;
+  base = mmap (base, mapsize, PROT_READ | PROT_WRITE,
+	       MAP_PRIVATE | MAP_FIXED, dup (fd), foffset);
+  return (base);
+}
+
+
+#endif	/* HAVE_MMAP */