/*
 * 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/errors.c#2 $
 */

#include "errors.h"

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>

#include "permassert.h"
#include "statusCodes.h"

static const struct errorInfo errorList[] = {
  { "UDS_UNINITIALIZED", "UDS library is not initialized" },
  { "UDS_SHUTTINGDOWN", "UDS library is shutting down" },
  { "UDS_EMODULE_LOAD", "Could not load modules" },
  { "UDS_ENOTHREADS", "Could not create a new thread" },
  { "UDS_NOCONTEXT", "Could not find the requested library context" },
  { "UDS_DISABLED", "UDS library context is disabled" },
  { "UDS_CORRUPT_FILE", "Corrupt file" },
  { "UDS_UNKNOWN_ERROR", "Unknown error" },
  { "UDS_GRID_NO_SERVERS", "No servers in grid configuration" },
  { "UDS_GRID_CONFIG_INCONSISTENT", "Grid configuration inconsistent" },
  { "UDS_UNSUPPORTED_VERSION", "Unsupported version" },
  { "UDS_NO_INDEXSESSION", "Index session not known" },
  { "UDS_CORRUPT_DATA", "Index data in memory is corrupt" },
  { "UDS_SHORT_READ", "Could not read requested number of bytes" },
  { "UDS_AI_ERROR", "Network address and service translation error" },
  { "UDS_RESOURCE_LIMIT_EXCEEDED", "Internal resource limits exceeded" },
  { "UDS_WRONG_CONTEXT_TYPE", "Context type mismatch" },
  { "UDS_BLOCK_ADDRESS_REQUIRED", "A block address is required" },
  { "UDS_CHUNK_DATA_REQUIRED", "Block data is required" },
  { "UDS_CHUNK_NAME_REQUIRED", "A chunk name is required" },
  { "UDS_CONF_PTR_REQUIRED", "A configuration pointer is required" },
  { "UDS_INDEX_STATS_PTR_REQUIRED", "An index stats pointer is required" },
  { "UDS_CONTEXT_STATS_PTR_REQUIRED", "A context stats pointer is required" },
  { "UDS_CONTEXT_PTR_REQUIRED", "A context pointer is required" },
  { "UDS_FILEID_REQUIRED", "A file ID is required" },
  { "UDS_STREAM_REQUIRED", "A stream is required" },
  { "UDS_STREAMID_REQUIRED", "A stream ID is required" },
  { "UDS_STREAM_PTR_REQUIRED", "A stream pointer is required" },
  { "UDS_INVALID_MEMORY_SIZE",
    "Configured memory too small or unsupported size" },
  { "UDS_INVALID_METADATA_SIZE", "Invalid metadata size" },
  { "UDS_INDEX_NAME_REQUIRED", "An index name is required" },
  { "UDS_CONF_REQUIRED", "A configuration is required" },
  { "UDS_BAD_FILE_DESCRIPTOR", "Bad file descriptor" },
  { "UDS_INDEX_EXISTS", "Index already exists" },
  { "UDS_REQUESTS_OUT_OF_RANGE", "Maximum request value out of range" },
  { "UDS_BAD_NAMESPACE", "Bad namespace" },
  { "UDS_MIGRATOR_MISMATCH",
    "Migrator arguments do not match reader arguments" },
  { "UDS_NO_INDEX", "No index found" },
  { "UDS_BAD_CHECKPOINT_FREQUENCY", "Checkpoint frequency out of range" },
  { "UDS_WRONG_INDEX_CONFIG", "Wrong type of index configuration" },
  { "UDS_INDEX_PATH_NOT_DIR", "Index path does not point to a directory" },
  { "UDS_ALREADY_OPEN", "Open invoked on already opened connection" },
  { "UDS_CALLBACK_ALREADY_REGISTERED", "Callback already registered" },
  { "UDS_INDEX_PATH_TOO_LONG", "Index path too long" },
  { "UDS_END_OF_FILE", "Unexpected end of file" },
  { "UDS_INDEX_NOT_SAVED_CLEANLY", "Index not saved cleanly" },
};

static const struct errorInfo internalErrorList[] = {
  { "UDS_PROTOCOL_ERROR", "Client/server protocol error" },
  { "UDS_OVERFLOW", "Index overflow" },
  { "UDS_FILLDONE", "Fill phase done" },
  { "UDS_INVALID_ARGUMENT", "Invalid argument passed to internal routine" },
  { "UDS_BAD_STATE", "UDS data structures are in an invalid state" },
  { "UDS_DUPLICATE_NAME",
    "Attempt to enter the same name into a delta index twice" },
  { "UDS_UNEXPECTED_RESULT", "Unexpected result from internal routine" },
  { "UDS_INJECTED_ERROR", "Injected error" },
  { "UDS_ASSERTION_FAILED", "Assertion failed" },
  { "UDS_UNSCANNABLE", "Unscannable" },
  { "UDS_QUEUED", "Request queued" },
  { "UDS_QUEUE_ALREADY_CONNECTED", "Queue already connected" },
  { "UDS_BAD_FILL_PHASE", "Fill phase not supported" },
  { "UDS_BUFFER_ERROR", "Buffer error" },
  { "UDS_CONNECTION_LOST", "Lost connection to peer" },
  { "UDS_TIMEOUT", "A time out has occurred" },
  { "UDS_NO_DIRECTORY", "Expected directory is missing" },
  { "UDS_CHECKPOINT_INCOMPLETE", "Checkpoint not completed" },
  { "UDS_INVALID_RUN_ID", "Invalid albGenTest server run ID" },
  { "UDS_RUN_CANCELED", "albGenTest server run canceled" },
  { "UDS_ALREADY_REGISTERED", "error range already registered" },
};

/** Error attributes - or into top half of error code */
enum {
  UDS_UNRECOVERABLE = (1 << 17)
};

typedef struct errorBlock {
  const char      *name;
  int              base;
  int              last;
  int              max;
  const ErrorInfo *infos;
} ErrorBlock;

enum {
  MAX_ERROR_BLOCKS = 6          // needed for testing
};

static struct errorInformation {
  int        allocated;
  int        count;
  ErrorBlock blocks[MAX_ERROR_BLOCKS];
} registeredErrors;

/**********************************************************************/
void initializeStandardErrorBlocks(void)
{
  registeredErrors.allocated = MAX_ERROR_BLOCKS;
  registeredErrors.count   = 0;


  registeredErrors.blocks[registeredErrors.count++] = (ErrorBlock) {
    .name  = "UDS Error",
    .base  = UDS_ERROR_CODE_BASE,
    .last  = UDS_ERROR_CODE_LAST,
    .max   = UDS_ERROR_CODE_BLOCK_END,
    .infos = errorList,
  };

  registeredErrors.blocks[registeredErrors.count++] = (ErrorBlock) {
    .name  = "UDS Internal Error",
    .base  = UDS_INTERNAL_ERROR_CODE_BASE,
    .last  = UDS_INTERNAL_ERROR_CODE_LAST,
    .max   = UDS_INTERNAL_ERROR_CODE_BLOCK_END,
    .infos = internalErrorList,
  };

  registeredErrors.blocks[registeredErrors.count++] = (ErrorBlock) {
    .name  = THIS_MODULE->name,
    .base  = VDO_BLOCK_START,
    .last  = VDO_STATUS_CODE_LAST,
    .max   = VDO_BLOCK_END,
    .infos = vdoStatusList,
  };
}

/**
 * Fetch the error info (if any) for the error number.
 *
 * @param errnum        the error number
 * @param infoPtr       the place to store the info for this error (if known),
 *                      otherwise set to NULL
 *
 * @return              the name of the error block (if known), NULL otherwise
 **/
static const char *getErrorInfo(int errnum, const ErrorInfo **infoPtr)
{
  for (ErrorBlock *block = registeredErrors.blocks;
       block < registeredErrors.blocks + registeredErrors.count;
       ++block) {
    if ((errnum >= block->base) && (errnum < block->last)) {
      if (infoPtr != NULL) {
        *infoPtr = block->infos + (errnum - block->base);
      }
      return block->name;
    } else if ((errnum >= block->last) && (errnum < block->max)) {
      if (infoPtr != NULL) {
        *infoPtr = NULL;
      }
      return block->name;
    }
  }
  if (infoPtr != NULL) {
    *infoPtr = NULL;
  }
  return NULL;
}

/*****************************************************************************/
const char *stringError(int errnum, char *buf, size_t buflen)
{
  if (buf == NULL) {
    return NULL;
  }

  const ErrorInfo *info      = NULL;
  const char      *blockName = getErrorInfo(errnum, &info);

  if (blockName != NULL) {
    if (info != NULL) {
      snprintf(buf, buflen, "%s: %s", blockName, info->message);
    } else {
      snprintf(buf, buflen, "Unknown %s %d", blockName, errnum);
    }
  } else {
    snprintf(buf, buflen, "System error %d", errnum);
  }
  return buf;
}

/*****************************************************************************/
const char *stringErrorName(int errnum, char *buf, size_t buflen)
{
  const ErrorInfo *info      = NULL;
  const char      *blockName = getErrorInfo(errnum, &info);

  if (blockName != NULL) {
    if (info != NULL) {
      snprintf(buf, buflen, "%s: %s", blockName, info->name);
    } else {
      snprintf(buf, buflen, "Unknown %s %d", blockName, errnum);
    }
  } else {
    snprintf(buf, buflen, "System error %d", errnum);
  }
  return buf;
}

/*****************************************************************************/
int makeUnrecoverable(int resultCode)
{
  return ((resultCode == UDS_SUCCESS)
          ? resultCode
          : (resultCode | UDS_UNRECOVERABLE));
}

/*****************************************************************************/
int sansUnrecoverable(int resultCode)
{
  return resultCode & ~UDS_UNRECOVERABLE;
}

/*****************************************************************************/
bool isUnrecoverable(int resultCode)
{
  return (bool)(resultCode & UDS_UNRECOVERABLE);
}

/*****************************************************************************/
int registerErrorBlock(const char      *blockName,
                       int              firstError,
                       int              lastReservedError,
                       const ErrorInfo *infos,
                       size_t           infoSize)
{
  int result = ASSERT(firstError < lastReservedError,
                      "bad error block range");
  if (result != UDS_SUCCESS) {
    return result;
  }

  if (registeredErrors.count == registeredErrors.allocated) {
    // could reallocate and grow, but should never happen
    return UDS_OVERFLOW;
  }

  for (ErrorBlock *block = registeredErrors.blocks;
       block < registeredErrors.blocks + registeredErrors.count;
       ++block) {
    if (strcmp(blockName, block->name) == 0) {
      return UDS_DUPLICATE_NAME;
    }
    // check for overlap in error ranges
    if ((firstError < block->max) && (lastReservedError > block->base)) {
      return UDS_ALREADY_REGISTERED;
    }
  }

  registeredErrors.blocks[registeredErrors.count++] = (ErrorBlock) {
    .name  = blockName,
    .base  = firstError,
    .last  = firstError + (infoSize / sizeof(ErrorInfo)),
    .max   = lastReservedError,
    .infos = infos
  };

  return UDS_SUCCESS;
}