/*
 * Copyright (c) 2006 Ondrej Palkovsky
 * 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.
 * - 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.
 */

/** @addtogroup klog KLog
 * @brief HelenOS KLog
 * @{
 */
/**
 * @file
 */

#include <stdio.h>
#include <async.h>
#include <as.h>
#include <ddi.h>
#include <event.h>
#include <errno.h>
#include <str_error.h>
#include <io/klog.h>
#include <sysinfo.h>
#include <malloc.h>
#include <fibril_synch.h>
#include <adt/list.h>
#include <adt/prodcons.h>

#define NAME       "klog"
#define LOG_FNAME  "/log/klog"

/* Producer/consumer buffers */
typedef struct {
	link_t link;
	size_t length;
	wchar_t *data;
} item_t;

static prodcons_t pc;

/* Pointer to klog area */
static wchar_t *klog;
static size_t klog_length;

/* Notification mutex */
static FIBRIL_MUTEX_INITIALIZE(mtx);

/** Klog producer
 *
 * Copies the contents of a character buffer to local
 * producer/consumer queue.
 *
 * @param length Number of characters to copy.
 * @param data   Pointer to the kernel klog buffer.
 *
 */
static void producer(size_t length, wchar_t *data)
{
	item_t *item = (item_t *) malloc(sizeof(item_t));
	if (item == NULL)
		return;
	
	size_t sz = sizeof(wchar_t) * length;
	wchar_t *buf = (wchar_t *) malloc(sz);
	if (data == NULL) {
		free(item);
		return;
	}
	
	memcpy(buf, data, sz);
	
	link_initialize(&item->link);
	item->length = length;
	item->data = buf;
	prodcons_produce(&pc, &item->link);
}

/** Klog consumer
 *
 * Waits in an infinite loop for the character data created by
 * the producer and outputs them to stdout and optionally into
 * a file.
 *
 * @param data Unused.
 *
 * @return Always EOK (unreachable).
 *
 */
static int consumer(void *data)
{
	FILE *log = fopen(LOG_FNAME, "a");
	if (log == NULL)
		printf("%s: Unable to create log file %s (%s)\n", NAME, LOG_FNAME,
		    str_error(errno));
	
	while (true) {
		link_t *link = prodcons_consume(&pc);
		item_t *item = list_get_instance(link, item_t, link);
		
		for (size_t i = 0; i < item->length; i++)
			putchar(item->data[i]);
		
		if (log != NULL) {
			for (size_t i = 0; i < item->length; i++)
				fputc(item->data[i], log);
			
			fflush(log);
			fsync(fileno(log));
		}
		
		free(item->data);
		free(item);
	}
	
	fclose(log);
	return EOK;
}

/** Kernel notification handler
 *
 * Receives kernel klog notifications.
 *
 * @param callid IPC call ID
 * @param call   IPC call structure
 * @param arg    Local argument
 *
 */
static void notification_received(ipc_callid_t callid, ipc_call_t *call)
{
	/*
	 * Make sure we process only a single notification
	 * at any time to limit the chance of the consumer
	 * starving.
	 *
	 * Note: Usually the automatic masking of the klog
	 * notifications on the kernel side does the trick
	 * of limiting the chance of accidentally copying
	 * the same data multiple times. However, due to
	 * the non-blocking architecture of klog notifications,
	 * this possibility cannot be generally avoided.
	 */
	
	fibril_mutex_lock(&mtx);
	
	size_t klog_start = (size_t) IPC_GET_ARG1(*call);
	size_t klog_len = (size_t) IPC_GET_ARG2(*call);
	size_t klog_stored = (size_t) IPC_GET_ARG3(*call);
	
	size_t offset = (klog_start + klog_len - klog_stored) % klog_length;
	
	/* Copy data from the ring buffer */
	if (offset + klog_stored >= klog_length) {
		size_t split = klog_length - offset;
		
		producer(split, klog + offset);
		producer(klog_stored - split, klog);
	} else
		producer(klog_stored, klog + offset);
	
	event_unmask(EVENT_KLOG);
	fibril_mutex_unlock(&mtx);
}

int main(int argc, char *argv[])
{
	size_t pages;
	int rc = sysinfo_get_value("klog.pages", &pages);
	if (rc != EOK) {
		fprintf(stderr, "%s: Unable to get number of klog pages\n",
		    NAME);
		return rc;
	}
	
	uintptr_t faddr;
	rc = sysinfo_get_value("klog.faddr", &faddr);
	if (rc != EOK) {
		fprintf(stderr, "%s: Unable to get klog physical address\n",
		    NAME);
		return rc;
	}
	
	size_t size = pages * PAGE_SIZE;
	klog_length = size / sizeof(wchar_t);
	
	rc = physmem_map((void *) faddr, pages,
	    AS_AREA_READ | AS_AREA_CACHEABLE, (void *) &klog);
	if (rc != EOK) {
		fprintf(stderr, "%s: Unable to map klog\n", NAME);
		return rc;
	}
	
	prodcons_initialize(&pc);
	async_set_interrupt_received(notification_received);
	rc = event_subscribe(EVENT_KLOG, 0);
	if (rc != EOK) {
		fprintf(stderr, "%s: Unable to register klog notifications\n",
		    NAME);
		return rc;
	}
	
	fid_t fid = fibril_create(consumer, NULL);
	if (!fid) {
		fprintf(stderr, "%s: Unable to create consumer fibril\n",
		    NAME);
		return ENOMEM;
	}
	
	fibril_add_ready(fid);
	event_unmask(EVENT_KLOG);
	klog_update();
	
	task_retval(0);
	async_manager();
	
	return 0;
}

/** @}
 */