1 files changed, 110 insertions, 0 deletions
diff --git a/libbacktrace/mmapio.c b/libbacktrace/mmapio.c
new file mode 100644
index 0000000..7f6fa8d
--- /dev/null
+++ b/libbacktrace/mmapio.c
@@ -0,0 +1,110 @@
+/* mmapio.c -- File views using mmap.
+   Copyright (C) 2012-2021 Free Software Foundation, Inc.
+   Written by Ian Lance Taylor, Google.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    (1) Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+
+    (2) Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in
+    the documentation and/or other materials provided with the
+    distribution.
+
+    (3) The name of the author may not be used to
+    endorse or promote products derived from this software without
+    specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.  */
+
+#include "config.h"
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include "backtrace.h"
+#include "internal.h"
+
+#ifndef HAVE_DECL_GETPAGESIZE
+extern int getpagesize (void);
+#endif
+
+#ifndef MAP_FAILED
+#define MAP_FAILED ((void *)-1)
+#endif
+
+/* This file implements file views and memory allocation when mmap is
+   available.  */
+
+/* Create a view of SIZE bytes from DESCRIPTOR at OFFSET.  */
+
+int
+backtrace_get_view (struct backtrace_state *state ATTRIBUTE_UNUSED,
+		    int descriptor, off_t offset, uint64_t size,
+		    backtrace_error_callback error_callback,
+		    void *data, struct backtrace_view *view)
+{
+  size_t pagesize;
+  unsigned int inpage;
+  off_t pageoff;
+  void *map;
+
+  if ((uint64_t) (size_t) size != size)
+    {
+      error_callback (data, "file size too large", 0);
+      return 0;
+    }
+
+  pagesize = getpagesize ();
+  inpage = offset % pagesize;
+  pageoff = offset - inpage;
+
+  size += inpage;
+  size = (size + (pagesize - 1)) & ~ (pagesize - 1);
+
+  map = mmap (NULL, size, PROT_READ, MAP_PRIVATE, descriptor, pageoff);
+  if (map == MAP_FAILED)
+    {
+      error_callback (data, "mmap", errno);
+      return 0;
+    }
+
+  view->data = (char *) map + inpage;
+  view->base = map;
+  view->len = size;
+
+  return 1;
+}
+
+/* Release a view read by backtrace_get_view.  */
+
+void
+backtrace_release_view (struct backtrace_state *state ATTRIBUTE_UNUSED,
+			struct backtrace_view *view,
+			backtrace_error_callback error_callback,
+			void *data)
+{
+  union {
+    const void *cv;
+    void *v;
+  } const_cast;
+
+  const_cast.cv = view->base;
+  if (munmap (const_cast.v, view->len) < 0)
+    error_callback (data, "munmap", errno);
+}