lora-irrigation/sysinit.c

/*-
 * Copyright 2022 John-Mark Gurney.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <sysinit.h>

SET_DECLARE(sysinit_set, struct sysinit);

void __attribute__ ((constructor))
sysinit_run(void)
{
	const int cnt = SET_COUNT(sysinit_set);
	uint16_t *idxarray = alloca(sizeof(uint16_t) * cnt);
#if defined(VERBOSE_SYSINIT)
	uint16_t last;
	bool verbose;
#endif
	int i;

	for (i = 0; i < cnt; i++)
		idxarray[i] = i;

	/*
	 * following mostly copied from FreeBSD sys/kern/init_main.c
	 * which has license:
	 * SPDX-License-Identifier: BSD-4-Clause
	 *
	 * Copyright (c) 1995 Terrence R. Lambert
	 * All rights reserved.
	 *
	 * Copyright (c) 1982, 1986, 1989, 1991, 1992, 1993
	 *      The Regents of the University of California.  All rights reserved.
	 * (c) UNIX System Laboratories, Inc.
	 *
	 * as copying this to RAM might be expensive, use a stack
	 * allocated indirection array to do the sorting instead.
	 */
	uint16_t *sipp;
	uint16_t *xipp;
	uint16_t save;

	/*
	 * Perform a bubble sort of the system initialization objects by
	 * their subsystem (primary key) and order (secondary key).
	 */
#define GI(x)	(SET_BEGIN(sysinit_set)[(x)])
#define GI_SUBSYSORDER(x)	(GI((x))->si_subsys_order)
#define GI_SUBSYS(x)		(GET_SUBSYS(GI_SUBSYSORDER(x)))
#define GI_ORDER(x)		(GET_ORDER(GI_SUBSYSORDER(x)))

	for (sipp = &idxarray[0]; sipp < &idxarray[cnt]; sipp++) {
		for (xipp = sipp + 1; xipp < &idxarray[cnt]; xipp++) {
			if (GI_SUBSYS(*sipp) < GI_SUBSYS(*xipp) ||
			     (GI_SUBSYS(*sipp) == GI_SUBSYS(*xipp) &&
			      GI_ORDER(*sipp) <= GI_ORDER(*xipp)))
				continue;	/* skip*/
			save = *sipp;
			*sipp = *xipp;
			*xipp = save;
		}
	}

#if defined(VERBOSE_SYSINIT)
	last = SI_SUB_COPYRIGHT;
	verbose = 0;
#endif
	/*
	 * Traverse the (now) ordered list of system initialization tasks.
	 * Perform each task, and continue on to the next task.
	 */
	for (sipp = &idxarray[0]; sipp < &idxarray[cnt]; sipp++) {
		if (GI_SUBSYS(*sipp) == SI_SUB_DUMMY)
			continue;	/* skip dummy task(s)*/

#if defined(VERBOSE_SYSINIT)
		if (GI_SUBSYS(*sipp) > last && verbose_sysinit != 0) {
			verbose = 1;
			last = GI_SUBSYS(*sipp);
			printf("subsystem %x\n", last);
		}
		if (verbose) {
				printf("   %p(%p)... ", GI(*sipp)->func,
				    GI(*sipp)->udata);
		}
#endif

		/* Call function */
		(GI(*sipp)->si_func)(GI(*sipp)->si_udata);

#if defined(VERBOSE_SYSINIT)
		if (verbose)
			printf("done.\n");
#endif
	}
}