Clean up abort.

* A dlmalloc usage error shouldn't call abort(3) because we want to
  cause a SIGSEGV by writing the address dlmalloc didn't like to an
  address the kernel won't like, so that debuggerd will dump the
  memory around the address that upset dlmalloc.

* Switch to the simpler FreeBSD/NetBSD style of registering stdio
  cleanup. Hopefully this will let us simplify more of the stdio
  implementation.

* Clear the stdio cleanup handler before we abort because of a dlmalloc
  corruption error. This fixes the reported bug, where we'd hang inside
  dlmalloc because the stdio cleanup reentered dlmalloc.

Bug: 9301265
Change-Id: Ief31b389455d6876e5a68f0f5429567d37277dbc

libc/bionic/abort.cpp

@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 1985 Regents of the University of California.
+ * All rights reserved.
+ *
+ * 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. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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 <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include "atexit.h"
+
+__LIBC_HIDDEN__ void (*__cleanup)();
+
+#ifdef __arm__
+extern "C" __LIBC_HIDDEN__ void __libc_android_abort()
+#else
+void abort()
+#endif
+{
+  // Don't block SIGABRT to give any signal handler a chance; we ignore
+  // any errors -- X311J doesn't allow abort to return anyway.
+  sigset_t mask;
+  sigfillset(&mask);
+  sigdelset(&mask, SIGABRT);
+  sigprocmask(SIG_SETMASK, &mask, NULL);
+
+  // POSIX requires we flush stdio buffers on abort.
+  if (__cleanup) {
+    (*__cleanup)();
+  }
+
+  raise(SIGABRT);
+
+  // If SIGABRT ignored, or caught and the handler returns,
+  // remove the SIGABRT signal handler and raise SIGABRT again.
+  struct sigaction sa;
+  sa.sa_handler = SIG_DFL;
+  sa.sa_flags   = SA_RESTART;
+  sigemptyset(&sa.sa_mask);
+  sigaction(SIGABRT, &sa, &sa);
+  sigprocmask(SIG_SETMASK, &mask, NULL);
+  raise(SIGABRT);
+  _exit(1);
+}