Use libbacktrace to generate better leak callstacks.

git-svn-id: https://www.unprompted.com/svn/projects/tildefriends/trunk@3986 ed5197a5-7fde-0310-b194-c3ffbd925b24

deps/libbacktrace/instrumented_alloc.c

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+/* instrumented_alloc.c -- Memory allocation instrumented to fail when
+   requested, for testing purposes.
+   Copyright (C) 2018-2021 Free Software Foundation, Inc.
+
+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 all the header files of alloc here, to make sure they're not
+   processed when including alloc.c below, such that the redefinitions of malloc
+   and realloc are only effective in alloc.c itself.  This does not work for
+   config.h, because it's not wrapped in "#ifndef CONFIG_H\n#define CONFIG_H"
+   and "#endif" but that does not seem to be harmful.  */
+
+#include "config.h"
+
+#include <errno.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <inttypes.h>
+
+#include "backtrace.h"
+#include "internal.h"
+
+extern void *instrumented_malloc (size_t size);
+extern void *instrumented_realloc (void *ptr, size_t size);
+
+#define malloc instrumented_malloc
+#define realloc instrumented_realloc
+#include "alloc.c"
+#undef malloc
+#undef realloc
+
+static uint64_t nr_allocs = 0;
+static uint64_t fail_at_alloc = 0;
+
+extern int at_fail_alloc_p (void);
+extern uint64_t get_nr_allocs (void);
+extern void set_fail_at_alloc (uint64_t);
+
+void *
+instrumented_malloc (size_t size)
+{
+  void *res;
+
+  if (at_fail_alloc_p ())
+    return NULL;
+
+  res = malloc (size);
+  if (res != NULL)
+    nr_allocs++;
+
+  return res;
+}
+
+void *
+instrumented_realloc (void *ptr, size_t size)
+{
+  void *res;
+
+  if (size != 0)
+    {
+      if (at_fail_alloc_p ())
+	return NULL;
+    }
+
+  res = realloc (ptr, size);
+  if (res != NULL)
+    nr_allocs++;
+
+  return res;
+}
+
+int
+at_fail_alloc_p (void)
+{
+  return fail_at_alloc == nr_allocs + 1;
+}
+
+uint64_t
+get_nr_allocs (void)
+{
+  return nr_allocs;
+}
+
+void
+set_fail_at_alloc (uint64_t nr)
+{
+  fail_at_alloc = nr;
+}