source: mainline/uspace/lib/usb/src/debug.c@ aa389fd

/*
 * Copyright (c) 2010-2011 Vojtech Horky
 * 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 libusb
 * @{
 */
/** @file
 * @brief Debugging support.
 */
#include <adt/list.h>
#include <fibril_synch.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <usb/debug.h>

/** Debugging tag. */
typedef struct {
        /** Linked list member. */
        link_t link;
        /** Tag name.
         * We always have a private copy of the name.
         */
        char *tag;
        /** Enabled level of debugging. */
        int level;
} usb_debug_tag_t;

/** Get instance of usb_debug_tag_t from link_t. */
#define USB_DEBUG_TAG_INSTANCE(iterator) \
        list_get_instance(iterator, usb_debug_tag_t, link)

/** List of all known tags. */
static LIST_INITIALIZE(tag_list);
/** Mutex guard for the list of all tags. */
static FIBRIL_MUTEX_INITIALIZE(tag_list_guard);

/** Level of logging messages. */
static usb_log_level_t log_level = USB_LOG_LEVEL_WARNING;
/** Prefix for logging messages. */
static const char *log_prefix = "usb";
/** Serialization mutex for logging functions. */
static FIBRIL_MUTEX_INITIALIZE(log_serializer);
static FILE *log_stream = NULL;

/** Find or create new tag with given name.
 *
 * @param tagname Tag name.
 * @return Debug tag structure.
 * @retval NULL Out of memory.
 */
static usb_debug_tag_t *get_tag(const char *tagname)
{
        link_t *link;
        for (link = tag_list.next; \
            link != &tag_list; \
            link = link->next) {
                usb_debug_tag_t *tag = USB_DEBUG_TAG_INSTANCE(link);
                if (str_cmp(tag->tag, tagname) == 0) {
                        return tag;
                }
        }

        /*
         * Tag not found, we will create a new one.
         */
        usb_debug_tag_t *new_tag = malloc(sizeof(usb_debug_tag_t));
        int rc = asprintf(&new_tag->tag, "%s", tagname);
        if (rc < 0) {
                free(new_tag);
                return NULL;
        }
        list_initialize(&new_tag->link);
        new_tag->level = 1;

        /*
         * Append it to the end of known tags.
         */
        list_append(&new_tag->link, &tag_list);

        return new_tag;
}

/** Print debugging information.
 * If the tag is used for the first time, its structures are automatically
 * created and initial verbosity level is set to 1.
 *
 * @param tagname Tag name.
 * @param level Level (verbosity) of the message.
 * @param format Formatting string for printf().
 */
void usb_dprintf(const char *tagname, int level, const char *format, ...)
{
        fibril_mutex_lock(&tag_list_guard);
        usb_debug_tag_t *tag = get_tag(tagname);
        if (tag == NULL) {
                printf("USB debug: FATAL ERROR - failed to create tag.\n");
                goto leave;
        }

        if (tag->level < level) {
                goto leave;
        }

        va_list args;
        va_start(args, format);

        printf("[%s:%d]: ", tagname, level);
        vprintf(format, args);

        va_end(args);

leave:
        fibril_mutex_unlock(&tag_list_guard);
}

/** Enable debugging prints for given tag.
 *
 * Setting level to <i>n</i> will cause that only printing messages
 * with level lower or equal to <i>n</i> will be printed.
 *
 * @param tagname Tag name.
 * @param level Enabled level.
 */
void usb_dprintf_enable(const char *tagname, int level)
{
        fibril_mutex_lock(&tag_list_guard);
        usb_debug_tag_t *tag = get_tag(tagname);
        if (tag == NULL) {
                printf("USB debug: FATAL ERROR - failed to create tag.\n");
                goto leave;
        }

        tag->level = level;

leave:
        fibril_mutex_unlock(&tag_list_guard);
}

/** Enable logging.
 *
 * @param level Maximal enabled level (including this one).
 * @param message_prefix Prefix for each printed message.
 */
void usb_log_enable(usb_log_level_t level, const char *message_prefix)
{
        log_prefix = message_prefix;
        log_level = level;
        if (log_stream == NULL) {
                char *fname;
                int rc = asprintf(&fname, "/log/%s", message_prefix);
                if (rc > 0) {
                        log_stream = fopen(fname, "w");
                        free(fname);
                }
        }
}


static const char *log_level_name(usb_log_level_t level)
{
        switch (level) {
                case USB_LOG_LEVEL_FATAL:
                        return " FATAL";
                case USB_LOG_LEVEL_ERROR:
                        return " ERROR";
                case USB_LOG_LEVEL_WARNING:
                        return " WARN";
                case USB_LOG_LEVEL_INFO:
                        return " info";
                default:
                        return "";
        }
}

/** Print logging message.
 *
 * @param level Verbosity level of the message.
 * @param format Formatting directive.
 */
void usb_log_printf(usb_log_level_t level, const char *format, ...)
{
        FILE *stream = NULL;
        switch (level) {
                case USB_LOG_LEVEL_FATAL:
                case USB_LOG_LEVEL_ERROR:
                        stream = stderr;
                        break;
                default:
                        stream = stdout;
                        break;
        }
        assert(stream != NULL);

        va_list args;
        va_start(args, format);

        /*
         * Serialize access to log files.
         * Always print to log file, to screen print only when the enabled
         * log level is high enough.
         */
        fibril_mutex_lock(&log_serializer);

        const char *level_name = log_level_name(level);

        if (log_stream != NULL) {
                fprintf(log_stream, "[%s]%s: ", log_prefix, level_name);
                vfprintf(log_stream, format, args);
        }

        if (level <= log_level) {
                fprintf(stream, "[%s]%s: ", log_prefix, level_name);
                vfprintf(stream, format, args);
        }

        fibril_mutex_unlock(&log_serializer);

        va_end(args);
}

/**
 * @}
 */