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+/* read.c -- File views without 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 <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "backtrace.h"
+#include "internal.h"
+
+/* This file implements file views when mmap is not available. */
+
+/* Create a view of SIZE bytes from DESCRIPTOR at OFFSET. */
+
+int
+backtrace_get_view (struct backtrace_state *state, int descriptor,
+ off_t offset, uint64_t size,
+ backtrace_error_callback error_callback,
+ void *data, struct backtrace_view *view)
+{
+ uint64_t got;
+ ssize_t r;
+
+ if ((uint64_t) (size_t) size != size)
+ {
+ error_callback (data, "file size too large", 0);
+ return 0;
+ }
+
+ if (lseek (descriptor, offset, SEEK_SET) < 0)
+ {
+ error_callback (data, "lseek", errno);
+ return 0;
+ }
+
+ view->base = backtrace_alloc (state, size, error_callback, data);
+ if (view->base == NULL)
+ return 0;
+ view->data = view->base;
+ view->len = size;
+
+ got = 0;
+ while (got < size)
+ {
+ r = read (descriptor, view->base, size - got);
+ if (r < 0)
+ {
+ error_callback (data, "read", errno);
+ free (view->base);
+ return 0;
+ }
+ if (r == 0)
+ break;
+ got += (uint64_t) r;
+ }
+
+ if (got < size)
+ {
+ error_callback (data, "file too short", 0);
+ free (view->base);
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Release a view read by backtrace_get_view. */
+
+void
+backtrace_release_view (struct backtrace_state *state,
+ struct backtrace_view *view,
+ backtrace_error_callback error_callback,
+ void *data)
+{
+ backtrace_free (state, view->base, view->len, error_callback, data);
+ view->data = NULL;
+ view->base = NULL;
+}