lib/libc-trusty/libc_init.c

/*
 * Copyright (C) 2008 The Android Open Source Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
 * COPYRIGHT OWNER 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 <compiler.h>
#include <stddef.h>
#include <trusty_std.h>

#include "libc_fatal.h"
#include "libc_init.h"
#include "atexit.h"

static void call_array(void(**list)(void)) {
  // First element is -1, list is null-terminated
  while (*++list) {
    (*list)();
  }
}

__NO_RETURN void __libc_init(void *args,
			int (*slingshot)(int, char**, char**),
			structors_array_t const * const structors)
{
	int ret;
	call_array(structors->preinit_array);
	call_array(structors->init_array);

	if (structors->fini_array != NULL) {
		ret = __cxa_atexit(__libc_fini, structors->fini_array);
		if (ret)
			__libc_fatal("__cxa_atexit failed\n");
	}

	exit(slingshot(0, NULL, NULL));
}

/* This function will be called during normal program termination
 * to run the destructors that are listed in the .fini_array section
 * of the executable, if any.
 *
 * 'fini_array' points to a list of function addresses. The first
 * entry in the list has value -1, the last one has value 0.
 */
void __libc_fini(void* array) {
  void** fini_array = (void **)array;
  const size_t minus1 = ~(size_t)0; /* ensure proper sign extension */

  /* Sanity check - first entry must be -1 */
  if (array == NULL || (size_t)fini_array[0] != minus1) {
    return;
  }

  /* skip over it */
  fini_array += 1;

  /* Count the number of destructors. */
  int count = 0;
  while (fini_array[count] != NULL) {
    ++count;
  }

  /* Now call each destructor in reverse order. */
  while (count > 0) {
    void (*func)(void) = (void (*)(void)) fini_array[--count];

    /* Sanity check, any -1 in the list is ignored */
    if ((size_t)func == minus1) {
      continue;
    }

    func();
  }
}