source: mainline/uspace/lib/c/generic/io/log.c@ a1a101d

/*
 * Copyright (c) 2011 Vojtech Horky
 * Copyright (c) 2011 Jiri Svoboda
 * 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 libc
 * @{
 */

#include <assert.h>
#include <errno.h>
#include <fibril_synch.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <async.h>
#include <io/log.h>
#include <ipc/logger.h>
#include <ns.h>

static sysarg_t default_log_id;

/** Log messages are printed under this name. */
static const char *log_prog_name;

static const char *log_level_names[] = {
        "fatal",
        "error",
        "warn",
        "note",
        "debug",
        "debug2",
        NULL
};

/** IPC session with the logger service. */
static async_sess_t *logger_session;

/** Maximum length of a single log message (in bytes). */
#define MESSAGE_BUFFER_SIZE 4096

static int logger_message(async_sess_t *session, log_t log, log_level_t level, const char *message)
{
        async_exch_t *exchange = async_exchange_begin(session);
        if (exchange == NULL) {
                return ENOMEM;
        }
        if (log == LOG_DEFAULT)
                log = default_log_id;

        aid_t reg_msg = async_send_2(exchange, LOGGER_WRITER_MESSAGE,
            log, level, NULL);
        int rc = async_data_write_start(exchange, message, str_size(message));
        sysarg_t reg_msg_rc;
        async_wait_for(reg_msg, &reg_msg_rc);

        async_exchange_end(exchange);

        /*
         * Getting ENAK means no-one wants our message. That is not an
         * error at all.
         */
        if (rc == ENAK)
                rc = EOK;

        if (rc != EOK) {
                return rc;
        }

        return reg_msg_rc;
}

const char *log_level_str(log_level_t level)
{
        if (level >= LVL_LIMIT)
                return "unknown";
        else
                return log_level_names[level];
}

int log_level_from_str(const char *name, log_level_t *level_out)
{
        log_level_t level = LVL_FATAL;

        while (log_level_names[level] != NULL) {
                if (str_cmp(name, log_level_names[level]) == 0) {
                        if (level_out != NULL)
                                *level_out = level;
                        return EOK;
                }
                level++;
        }

        /* Maybe user specified number directly. */
        char *end_ptr;
        int level_int = strtol(name, &end_ptr, 0);
        if ((end_ptr == name) || (str_length(end_ptr) != 0))
                return EINVAL;
        if (level_int < 0)
                return ERANGE;
        if (level_int >= (int) LVL_LIMIT)
                return ERANGE;

        if (level_out != NULL)
                *level_out = (log_level_t) level_int;

        return EOK;
}

/** Initialize the logging system.
 *
 * @param prog_name     Program name, will be printed as part of message
 */
int log_init(const char *prog_name)
{
        log_prog_name = str_dup(prog_name);
        if (log_prog_name == NULL)
                return ENOMEM;

        logger_session = service_connect_blocking(EXCHANGE_SERIALIZE, SERVICE_LOGGER, LOGGER_INTERFACE_WRITER, 0);
        if (logger_session == NULL) {
                return ENOMEM;
        }

        default_log_id = log_create(prog_name, LOG_NO_PARENT);

        return EOK;
}

/** Create a new (sub-) log.
 *
 * This function always returns a valid log_t. In case of errors,
 * @c parent is returned and errors are silently ignored.
 *
 * @param name Log name under which message will be reported (appended to parents name).
 * @param parent Parent log.
 * @return Opaque identifier of the newly created log.
 */
log_t log_create(const char *name, log_t parent)
{
        async_exch_t *exchange = async_exchange_begin(logger_session);
        if (exchange == NULL)
                return parent;

        if (parent == LOG_DEFAULT)
                parent = default_log_id;

        ipc_call_t answer;
        aid_t reg_msg = async_send_1(exchange, LOGGER_WRITER_CREATE_LOG,
            parent, &answer);
        int rc = async_data_write_start(exchange, name, str_size(name));
        sysarg_t reg_msg_rc;
        async_wait_for(reg_msg, &reg_msg_rc);

        async_exchange_end(exchange);

        if ((rc != EOK) || (reg_msg_rc != EOK))
                return parent;

        return IPC_GET_ARG1(answer);
}

/** Write an entry to the log.
 *
 * @param level         Message verbosity level. Message is only printed
 *                      if verbosity is less than or equal to current
 *                      reporting level.
 * @param fmt           Format string (no traling newline).
 */
void log_msg(log_t ctx, log_level_t level, const char *fmt, ...)
{
        va_list args;

        va_start(args, fmt);
        log_msgv(ctx, level, fmt, args);
        va_end(args);
}

/** Write an entry to the log (va_list variant).
 *
 * @param level         Message verbosity level. Message is only printed
 *                      if verbosity is less than or equal to current
 *                      reporting level.
 * @param fmt           Format string (no trailing newline)
 */
void log_msgv(log_t ctx, log_level_t level, const char *fmt, va_list args)
{
        assert(level < LVL_LIMIT);

        char *message_buffer = malloc(MESSAGE_BUFFER_SIZE);
        if (message_buffer == NULL) {
                return;
        }

        vsnprintf(message_buffer, MESSAGE_BUFFER_SIZE, fmt, args);
        logger_message(logger_session, ctx, level, message_buffer);
}

/** @}
 */