/*

 * 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/vdo-releases/aluminum/src/c++/vdo/kernel/logger.c#4 $

 */

#include "logger.h"

#include <linux/delay.h>

#include <linux/hardirq.h>

#include <linux/module.h>

#include "errors.h"

#include "threadDevice.h"

static const int  DEFAULT_PRIORITY = LOG_INFO;

typedef struct {

  const char *name;

  const int   priority;

} PRIORITY_NAMES;

static const PRIORITY_NAMES PRIORITIES[] = {

  { "ALERT",     LOG_ALERT },

  { "CRIT",      LOG_CRIT },

  { "CRITICAL",  LOG_CRIT },

  { "DEBUG",     LOG_DEBUG },

  { "EMERG",     LOG_EMERG },

  { "EMERGENCY", LOG_EMERG },

  { "ERR",       LOG_ERR },

  { "ERROR",     LOG_ERR },

  { "INFO",      LOG_INFO },

  { "NOTICE",    LOG_NOTICE },

  { "PANIC",     LOG_EMERG },

  { "WARN",      LOG_WARNING },

  { "WARNING",   LOG_WARNING },

  { NULL, -1 },

};

enum {

  PRIORITY_COUNT = 8

};

static const char *PRIORITY_STRINGS[] = {

  "EMERGENCY",

  "ALERT",

  "CRITICAL",

  "ERROR",

  "WARN",

  "NOTICE",

  "INFO",

  "DEBUG",

};

static int logLevel = LOG_INFO;

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

int stringToPriority(const char *string)

{

  for (int i = 0; PRIORITIES[i].name != NULL; i++) {

    if (strcasecmp(string, PRIORITIES[i].name) == 0) {

      return PRIORITIES[i].priority;

    }

  }

  return DEFAULT_PRIORITY;

}

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

int getLogLevel(void)

{

  return logLevel;

}

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

void setLogLevel(int newLogLevel)

{

  logLevel = newLogLevel;

}

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

const char *priorityToString(int priority)

{

  if ((priority < 0) || (priority >= PRIORITY_COUNT)) {

    return "unknown";

  }

  return PRIORITY_STRINGS[priority];

}

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

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";

}

/**

 * Emit a log message to the kernel log in a format suited to the current

 * thread context. Context info formats:

 *

 * interrupt:       kvdo[NMI]: blah

 * thread w/dev id: kvdo12:myprog: blah

 * kvdo thread:     kvdo12:foobarQ: blah

 * other thread:    kvdo: myprog: blah

 *

 * Fields: module name, interrupt level, process name, device ID.

 *

 * @param level       A string describing the logging level

 * @param moduleName  The name of the module doing the logging

 * @param prefix      The prefix of the log message

 * @param vaf1        The first message format descriptor

 * @param vaf2        The second message format descriptor

 **/

static void emitLogMessage(const char             *level,

                           const char             *moduleName,

                           const char             *prefix,

                           const struct va_format *vaf1,

                           const struct va_format *vaf2)

{

  if (in_interrupt()) {

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

           level, moduleName, getCurrentInterruptType(),

           prefix, vaf1, vaf2);

    return;

  }

  // Not at interrupt level; we have a process we can look at, and

  // might have a device ID.

  int deviceInstance = getThreadDeviceID();

  if (deviceInstance != -1) {

    printk("%s%s%u:%s: %s%pV%pV\n",

           level, moduleName, deviceInstance, current->comm,

           prefix, vaf1, vaf2);

    return;

  }

  if (((current->flags & PF_KTHREAD) != 0)

      && (strncmp(moduleName, current->comm, strlen(moduleName)) == 0)) {

    /*

     * It's a kernel thread starting with "kvdo" (or whatever). Assume it's

     * ours and that its name is sufficient.

     */

    printk("%s%s: %s%pV%pV\n",

           level, current->comm,

           prefix, vaf1, vaf2);

    return;

  }

  // Identify the module and the process.

  printk("%s%s: %s: %s%pV%pV\n",

         level, moduleName, current->comm,

         prefix, vaf1, vaf2);

}

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

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 = "";

  }

  emitLogMessage(priorityToLogLevel(priority), THIS_MODULE->name,

                 prefix, &vaf1, &vaf2);

  va_end(args1Copy);

  va_end(args2Copy);

}

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

void logEmbeddedMessage(int         priority,

                        const char *prefix,

                        const char *fmt1,

                        va_list     args1,

                        const char *fmt2,

                        ...)

{

  va_list ap;

  va_start(ap, fmt2);

  logMessagePack(priority, prefix, fmt1, args1, fmt2, ap);

  va_end(ap);

}

#pragma GCC diagnostic push

/*

 * GCC (version 8.1.1 20180502 (Red Hat 8.1.1-1)) on Fedora 28 seems

 * to think that this function should get a printf format

 * attribute. But we have no second format string, and no additional

 * arguments at the call site, and GCC also gets unhappy trying to

 * analyze the format and values when there are none. So we'll just

 * shut it up.

 */

#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"

/**

 * Log a message.

 *

 * This helper function exists solely to create a valid va_list with

 * no useful info. It does the real work of vLogMessage, which wants a

 * second va_list object to pass down.

 *

 * @param  priority The syslog priority value for the message.

 * @param  format   The format of the message (a printf style format)

 * @param  args     The variadic argument list of format parameters.

 **/

static void vLogMessageHelper(int         priority,

                              const char *format,

                              va_list     args,

                              ...)

{

  va_list dummy;

  va_start(dummy, args);

  logMessagePack(priority, NULL, format, args, NULL, dummy);

  va_end(dummy);

}

#pragma GCC diagnostic pop

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

void vLogMessage(int priority, const char *format, va_list args)

{

  vLogMessageHelper(priority, format, args);

}

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

void logMessage(int priority, const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogMessage(priority, format, args);

  va_end(args);

}

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

__attribute__((format(printf, 2, 3)))

static void logAtLevel(int priority, const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogMessage(priority, format, args);

  va_end(args);

}

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

void logDebug(const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogMessage(LOG_DEBUG, format, args);

  va_end(args);

}

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

void logInfo(const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogMessage(LOG_INFO, format, args);

  va_end(args);

}

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

void logNotice(const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogMessage(LOG_NOTICE, format, args);

  va_end(args);

}

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

void logWarning(const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogMessage(LOG_WARNING, format, args);

  va_end(args);

}

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

void logError(const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogMessage(LOG_ERR, format, args);

  va_end(args);

}

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

void vLogError(const char *format, va_list args)

{

  vLogMessage(LOG_ERR, format, args);

}

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

void logBacktrace(int priority)

{

  logAtLevel(priority, "[backtrace]");

  if (priority > logLevel) {

    return;

  }

  dump_stack();

}

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

int vLogWithStringError(int         priority,

                        int         errnum,

                        const char *format,

                        va_list     args)

{

  char errbuf[ERRBUF_SIZE] = "";

  logEmbeddedMessage(priority, NULL, format, args, ": %s (%d)",

                     stringError(errnum, errbuf, sizeof(errbuf)),

                     errnum);

  return errnum;

}

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

int logWithStringError(int priority, int errnum, const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogWithStringError(priority, errnum, format, args);

  va_end(args);

  return errnum;

}

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

int logErrorWithStringError(int errnum, const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogWithStringError(LOG_ERR, errnum, format, args);

  va_end(args);

  return errnum;

}

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

int vLogErrorWithStringError(int errnum, const char *format, va_list args)

{

  vLogWithStringError(LOG_ERR, errnum, format, args);

  return errnum;

}

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

int logWarningWithStringError(int errnum, const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogWithStringError(LOG_WARNING, errnum, format, args);

  va_end(args);

  return errnum;

}

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

int logDebugWithStringError(int errnum, const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogWithStringError(LOG_DEBUG, errnum, format, args);

  va_end(args);

  return errnum;

}

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

int logInfoWithStringError(int errnum, const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogWithStringError(LOG_INFO, errnum, format, args);

  va_end(args);

  return errnum;

}

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

int logNoticeWithStringError(int errnum, const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogWithStringError(LOG_NOTICE, errnum, format, args);

  va_end(args);

  return errnum;

}

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

int logFatalWithStringError(int errnum, const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogWithStringError(LOG_CRIT, errnum, format, args);

  va_end(args);

  return errnum;

}

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

int logUnrecoverable(int errnum, const char *format, ...)

{

  if ((errnum == UDS_SUCCESS || errnum == UDS_QUEUED) || (errnum == 0)) {

    return errnum;

  }

  va_list args;

  va_start(args, format);

  vLogWithStringError(LOG_CRIT, errnum, format, args);

  va_end(args);

  return makeUnrecoverable(errnum);

}

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

void logFatal(const char *format, ...)

{

  va_list args;

  va_start(args, format);

  vLogMessage(LOG_CRIT, format, args);

  va_end(args);

}

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

void pauseForLogger(void)

{

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

  // for the kernel log buffer to be flushed.

  msleep(4);

}