klog.c

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/*
 * 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.
 */

#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);

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);
}

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;
}

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);
        
        klog = (wchar_t *) as_get_mappable_page(size);
        if (klog == NULL) {
                fprintf(stderr, "%s: Unable to allocate virtual memory area\n",
                    NAME);
                return ENOMEM;
        }
        
        rc = physmem_map((void *) faddr, (void *) klog, pages,
            AS_AREA_READ | AS_AREA_CACHEABLE);
        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;
}

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