/*

 * Copyright (c) 2020 Red Hat, Inc.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 * 

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA. 

 *

 * $Id: //eng/uds-releases/jasper/kernelLinux/uds/loggerLinuxKernel.c#2 $

 */

#include <linux/delay.h>

#include <linux/hardirq.h>

#include <linux/module.h>

#include <linux/sched.h>

#include "logger.h"

/**********************************************************************/

static const char *priorityToLogLevel(int priority)

{

  switch (priority) {

    case LOG_EMERG:

    case LOG_ALERT:

    case LOG_CRIT:

      return KERN_CRIT;

    case LOG_ERR:

      return KERN_ERR;

    case LOG_WARNING:

      return KERN_WARNING;

    case LOG_NOTICE:

      return KERN_NOTICE;

    case LOG_INFO:

      return KERN_INFO;

    case LOG_DEBUG:

      return KERN_DEBUG;

    default:

      return "";

  }

}

/**********************************************************************/

static const char *getCurrentInterruptType(void)

{

  if (in_nmi()) {

    return "NMI";

  }

  if (in_irq()) {

    return "HI";

  }

  if (in_softirq()) {

    return "SI";

  }

  return "INTR";

}

/**********************************************************************/

void logMessagePack(int         priority,

                    const char *prefix,

                    const char *fmt1,

                    va_list     args1,

                    const char *fmt2,

                    va_list     args2)

{

  if (priority > getLogLevel()) {

    return;

  }

  /*

   * The kernel's printk has some magic for indirection to a secondary

   * va_list. It wants us to supply a pointer to the va_list.

   *

   * However, va_list varies across platforms and can be an array

   * type, which makes passing it around as an argument kind of

   * tricky, due to the automatic conversion to a pointer. This makes

   * taking the address of the argument a dicey thing; if we use "&a"

   * it works fine for non-array types, but for array types we get the

   * address of a pointer. Functions like va_copy and sprintf don't

   * care as they get "va_list" values passed and are written to do

   * the right thing, but printk explicitly wants the address of the

   * va_list.

   *

   * So, we copy the va_list values to ensure that "&" consistently

   * works the way we want.

   */

  va_list args1Copy;

  va_copy(args1Copy, args1);

  va_list args2Copy;

  va_copy(args2Copy, args2);

  struct va_format vaf1 = {

    .fmt = (fmt1 != NULL) ? fmt1 : "",

    .va  = &args1Copy,

  };

  struct va_format vaf2 = {

    .fmt = (fmt2 != NULL) ? fmt2 : "",

    .va  = &args2Copy,

  };

  if (prefix == NULL) {

    prefix = "";

  }

  /*

   * Context info formats:

   *

   * interrupt:   uds[NMI]: blah

   * process:     uds: myprog: blah

   *

   * Fields: module name, interrupt level or process name.

   *

   * XXX need the equivalent of VDO's deviceInstance here

   */

  if (in_interrupt()) {

    printk("%s%s[%s]: %s%pV%pV\n", priorityToLogLevel(priority),

	   THIS_MODULE->name, getCurrentInterruptType(), prefix, &vaf1, &vaf2);

  } else {

    printk("%s%s: %s: %s%pV%pV\n", priorityToLogLevel(priority),

	   THIS_MODULE->name, current->comm, prefix, &vaf1, &vaf2);

  }

  va_end(args1Copy);

  va_end(args2Copy);

}

/**********************************************************************/

void logBacktrace(int priority)

{

  if (priority > getLogLevel()) {

    return;

  }

  logMessage(priority, "[backtrace]");

  dump_stack();

}

/**********************************************************************/

void pauseForLogger(void)

{

  // Hopefully, a few milliseconds of sleep will be large enough

  // for the kernel log buffer to be flushed.

  msleep(4);

}