/* IBM_PROLOG_BEGIN_TAG                                                   */
/* This is an automatically generated prolog.                             */
/*                                                                        */
/*                                                                        */
/*                                                                        */
/* Licensed Materials - Property of IBM                                   */
/*                                                                        */
/* (C) COPYRIGHT International Business Machines Corp. 2002,2006          */
/* All Rights Reserved                                                    */
/*                                                                        */
/* US Government Users Restricted Rights - Use, duplication or            */
/* disclosure restricted by GSA ADP Schedule Contract with IBM Corp.      */
/*                                                                        */
/* IBM_PROLOG_END_TAG                                                     */

/*====================================================================
 *
 * tsreaddir command: Recursively traverse the directory structure
 *                    to list all files/directories in the file system.
 *
 * Syntax: tsreaddir [-d] [-n] [-t nThreads] [--] <pathname>
 *
 *   The "pathname" parameter should be the directory where the root of
 *   the file system is found.
 *
 *==================================================================*/

#ifdef GPFS_LINUX
/* Use 64 bit version of stat, etc. */
#define _LARGEFILE_SOURCE
#define _FILE_OFFSET_BITS 64

typedef long long offset_t;
#endif

#ifdef GPFS_AIX
/* Use 64 bit version of stat, etc. */
#ifndef _LARGE_FILES
#define _LARGE_FILES
#endif
#endif

#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <pthread.h>

#include <gpfs.h>

extern char *basename(char *);

int noDIR = 0;
int onlyDIR = 0;
int optcheck = 1;
char *RootFsDirP;

/* Define the number of threads used to read the directories */
#define DEFAULT_THREADS 16
int nThreads = DEFAULT_THREADS;

/* Define wait queue for threads */
static pthread_mutex_t QueueMutex;
static pthread_cond_t QueueCond;
static int NWorkersWaiting = 0;
static int NWorkersRunning = 0;

typedef struct queue_element
{
  struct queue_element *nextP;
  ino_t ino;
  char path[4];
} QueueElement;

static QueueElement *WorkQueueP = NULL;

/* Define mutex to serialize the output */
static pthread_mutex_t OutputMutex;

/* error code set while in threads to control final error code */
int exitrc = 0;



/* print usage message and exit */
void usage(char *argv0)
{
  fprintf(stderr, "Usage: %s [-d] [-n] [-t nThreads (def=%d)] [--] pathname\n",
          basename(argv0), DEFAULT_THREADS);
  exit(1);
}

/* Add an element to the work queue
   and signal any thread waiting for work. */
int EnqueueWork(const char *pathP, const char *dirP, ino_t inode)
{
  int rc;
  int pathLen = strlen(pathP);
  QueueElement *qP = NULL;

  /* Allocate a work queue element and space for the path.  */
  qP = (QueueElement *) malloc((sizeof(*qP) - sizeof(qP->path))
                                + pathLen + strlen(dirP) + 2);
  if (qP == NULL)
  {
    fprintf(stderr, "Out of memory.\n");
    return(ENOMEM);
  }

  /* Initialize element */
  qP->ino = inode;
  if (pathLen > 0)
  {
    strcpy(qP->path, pathP);
    strcat(qP->path, "/");
    strcat(qP->path, dirP);
  }
  else
    strcpy(qP->path, dirP);

  /* Acquire mutex protecting the work queue */
  rc = pthread_mutex_lock(&QueueMutex);
  if (rc != 0)
  {
    fprintf(stderr, "Error in pthread_mutex_lock: %s\n", strerror(rc));
    return rc;
  }

  /* Add work element to the list */
  qP->nextP = WorkQueueP;
  WorkQueueP = qP;

  /* Signal a waiting worker thread */
  if (NWorkersWaiting > 0)
  {
    NWorkersWaiting -= 1;
    rc = pthread_cond_signal(&QueueCond);
    if (rc != 0)
    {
      fprintf(stderr, "Error in pthread_cond_signal: %s\n", strerror(rc));
      return rc;
    }
  }

  /* Release mutex before returning */
  rc = pthread_mutex_unlock(&QueueMutex);
  if (rc != 0)
  {
    fprintf(stderr, "Error in pthread_mutex_unlock: %s\n", strerror(rc));
    return rc;
  }

  /* Success! */
  return 0;
}


/* Dequeue the next work element from the queue
   or if the queue is empty, wait for more work to become available */
QueueElement *DequeueWork(void)
{
  int rc;
  QueueElement *qP;

  /* Acquire mutex protecting the work queue */
  rc = pthread_mutex_lock(&QueueMutex);
  if (rc != 0)
  {
    fprintf(stderr, "Error in pthread_mutex_lock: %s\n", strerror(rc));
    if (exitrc == 0)
      exitrc = rc;
    return NULL;
  }

  /* One less thread working */
  NWorkersRunning -= 1;

  /* Loop waiting for work to become available */
  while ((WorkQueueP == NULL) && (NWorkersRunning > 0))
  {
    NWorkersWaiting += 1;       /* One more thread waiting */
    rc = pthread_cond_wait(&QueueCond, &QueueMutex);
    if (rc != 0)
    {
      fprintf(stderr, "Error in pthread_cond_wait: %s\n", strerror(rc));
      if (exitrc == 0)
        exitrc = rc;
      return NULL;
    }
  }

  /* Check if we are done */
  if (WorkQueueP == NULL)
  {
    qP = NULL;                  /* Nothing more to do. */

    /* signal any waiting threads */
    if (NWorkersWaiting > 0)
    {
      NWorkersWaiting = 0;
      rc = pthread_cond_broadcast(&QueueCond);
      if (rc != 0)
      {
        fprintf(stderr, "Error in pthread_cond_broadcast: %s\n", strerror(rc));
        if (exitrc == 0)
          exitrc = rc;
      }
    }
  }
  else
  {
    /* Remove the first element from the queue */
    qP = WorkQueueP;
    WorkQueueP = qP->nextP;
    qP->nextP = NULL;

    /* One more thread working */
    NWorkersRunning += 1;
  }

  /* Release mutex before returning */
  rc = pthread_mutex_unlock(&QueueMutex);
  if (rc != 0)
  {
    fprintf(stderr, "Error in pthread_mutex_unlock: %s\n", strerror(rc));
    if (exitrc == 0)
      exitrc = rc;
    return NULL;
  }

  return qP;
}

/* Main body for each thread.
   Loop until there is no more work to do. */
void* ThreadBody(void *parmP)
{
  int rc;
  QueueElement *qP;
  int read_dir(const char *, ino_t);

  /* Count this thread as a worker thread */
  rc = pthread_mutex_lock(&QueueMutex);
  if (rc != 0)
  {
    fprintf(stderr, "Error in pthread_mutex_lock: %s\n", strerror(rc));
    if (exitrc == 0)
      exitrc = rc;
    return NULL;
  }
  NWorkersRunning += 1;
  rc = pthread_mutex_unlock(&QueueMutex);
  if (rc != 0)
  {
    fprintf(stderr, "Error in pthread_mutex_unlock: %s\n", strerror(rc));
    NWorkersRunning -= 1;
    if (exitrc == 0)
      exitrc = rc;
    return NULL;
  }

  /* Loop while there is work to do */
  do
  {
    /* Wait for work */
    qP = DequeueWork();
    if (qP == NULL)
      break;

    /* Read this directory */
    rc = read_dir(qP->path, qP->ino);
    if (exitrc == 0)
      exitrc = rc;

    /* Free work queue element */
    free(qP);

  } while (rc == 0);

  rc = pthread_mutex_lock(&QueueMutex);
  if (rc != 0)
  {
    fprintf(stderr, "Error in pthread_mutex_lock: %s\n", strerror(rc));
    if (exitrc == 0)
      exitrc = rc;
    return NULL;
  }
  NWorkersRunning -= 1;
  rc = pthread_mutex_unlock(&QueueMutex);
  if (rc != 0)
  {
    fprintf(stderr, "Error in pthread_mutex_unlock: %s\n", strerror(rc));
    if (exitrc == 0)
      exitrc = rc;
  }

  return NULL;
}

/* Read all entries from the current directory */
int read_dir(const char *pathP, ino_t inode)
{
  int rc = 0;
  const gpfs_direntx_t *direntxP;
  gpfs_fssnap_handle_t *fsP = NULL;
  gpfs_ifile_t *dirxP = NULL;
  char *typeP, *slashP;
  int doprint;

  /* Check if we need a "/"  */
  if (strlen(pathP) > 0)
    slashP = "/";
  else
    slashP = "";

  /* Open the file system */
  fsP = gpfs_get_fssnaphandle_by_path(RootFsDirP);
  if (fsP == NULL)
  {
    rc = errno;
    fprintf(stderr, "gpfs_get_fssnaphandle_by_path(%s): %s\n",
            RootFsDirP, strerror(rc));
    goto exit;
  }

  /* Open the directory's file */
  dirxP = gpfs_iopen(fsP, inode, O_RDONLY, NULL, NULL);
  if (dirxP == NULL)
  {
    rc = errno;
    fprintf(stderr, "gpfs_iopen(%s/%s): %s\n", RootFsDirP, pathP, strerror(rc));
    goto exit;
  }

  /* Loop reading the directory entries */
  while (1)
  {
    rc = gpfs_ireaddir(dirxP, &direntxP);
    if (rc != 0)
    {
      int saveerrno = errno;
      fprintf(stderr, "gpfs_ireaddir(%s/%s): rc %d %s\n",
              RootFsDirP, pathP, rc, strerror(saveerrno));
      rc = saveerrno;
      goto exit;
    }
    if (direntxP == NULL)
      break;

    /* Get directory entry type */
    switch (direntxP->d_type)
    {
      case GPFS_DE_DIR:
        /* Skip . and .. entries */
        if ((strcmp(direntxP->d_name, ".") == 0) ||
            (strcmp(direntxP->d_name, "..") == 0))
          continue;

        typeP = "DIR";
        doprint = !noDIR;
        break;

      case GPFS_DE_REG:
        typeP = "REG";
        doprint = !onlyDIR;
        break;

      case GPFS_DE_LNK:
        typeP = "LNK";
        doprint = !onlyDIR;
        break;

      default:
        typeP = "UNK";
        doprint = !onlyDIR;
    }

    if (doprint)
    {
      int plen;

      /* Print file info on stdout.
         Serialize output with all other threads */
      rc = pthread_mutex_lock(&OutputMutex);
      if (rc != 0)
      {
        fprintf(stderr, "Error in pthread_mutex_lock: %s\n", strerror(rc));
        goto exit;
      }
      /* Print: inodenumber/generation type pathname
         (leading 0s on inodenumber/generation allow join command
          to do character sort to merge output with tstimes.) */
      plen = printf("%010d/%010d\t%s\t%s%s%s\n",
                    direntxP->d_ino, direntxP->d_gen, typeP,
                    pathP, slashP, direntxP->d_name);
      rc = pthread_mutex_unlock(&OutputMutex);
      if (rc != 0)
      {
        fprintf(stderr, "Error in pthread_mutex_unlock: %s\n", strerror(rc));
        goto exit;
      }
      if (plen < 0)
      {
        rc = errno;
        goto exit;
      }
    }

    /* Check if this entry is a directory */
    if (direntxP->d_type == GPFS_DE_DIR)
    {
      /* Add this directory to the work queue */
      rc = EnqueueWork(pathP, direntxP->d_name, direntxP->d_ino);
      if (rc != 0)
      {
        if (exitrc == 0)
          exitrc = rc;
        goto exit;
      }
    }
  }


exit:
  /* Close open file, if necessary */
  if (dirxP)
    gpfs_iclose(dirxP);
  if (fsP)
    gpfs_free_fssnaphandle(fsP);

  return rc;
}

/* main */
int main(int argc, char *argv[])
{
  int i, rc, filearg;
  struct stat statBuf;
  pthread_t pThread;

  /* Scan for options and single directory name */
  filearg = 0;
  for (i = 1; i < argc; i++)
  {
    if (0 == strcmp(argv[i], "-n"))
      noDIR = 1;
    else if (0 == strcmp(argv[i], "-d"))
      onlyDIR = 1;
    else if (0 == strcmp(argv[i], "-t"))
    {
      i += 1;
      if (i < argc)
        nThreads = atoi(argv[i]);
      else
        usage(argv[0]);
    }
    else if (0 == strcmp(argv[i], "--"))
      optcheck = 0;
    else if (optcheck && *argv[i] == '-')
      usage(argv[0]);
    else if (filearg == 0)
      filearg = i;
    else
      usage(argv[0]);
  }

  /* if no directory was specified, there is nothing to do */
  if (filearg == 0)
    usage(argv[0]);
  RootFsDirP = argv[filearg];

  /* Initialize pthread variables */
  rc = pthread_mutex_init(&QueueMutex, NULL);
  if (rc != 0)
  {
    fprintf(stderr, "Error from pthread_mutex_init: %s\n", strerror(rc));
    exit(rc);
  }
  rc = pthread_cond_init(&QueueCond, NULL);
  if (rc != 0)
  {
    fprintf(stderr, "Error from pthread_cond_init: %s\n", strerror(rc));
    exit(rc);
  }
  rc = pthread_mutex_init(&OutputMutex, NULL);
  if (rc != 0)
  {
    fprintf(stderr, "Error from pthread_mutex_init: %s\n", strerror(rc));
    exit(rc);
  }

  /* Get the inode number of the root directory */
  rc = stat(RootFsDirP, &statBuf);
  if (rc)
  {
    rc = errno;
    perror(RootFsDirP);
    return rc;
  }

  /* Verify this is a directory */
  if (!S_ISDIR(statBuf.st_mode))
  {
    errno = ENOTDIR;
    perror(RootFsDirP);
    return ENOTDIR;
  }

  if (!noDIR)
  {
    /* Print file info on stdout */
    rc = printf("%010d/%010d\tDIR\t%s\n", statBuf.st_ino, 1, RootFsDirP);
    if (rc < 0)
      return errno;
  }

  /* Add the root directory to the work queue */
  rc = EnqueueWork("", "", statBuf.st_ino);
  if (rc != 0)
    return rc;

  /* Start the requested number of threads */
  for (i = 1; i < nThreads; i++)
  {
    rc = pthread_create(&pThread, NULL, ThreadBody, NULL);
    if (rc != 0)
    {
      fprintf(stderr, "Error from pthread_create(%d): %s\n", i, strerror(rc));
      exit(rc);
    }
  }

  /* This thread can work too */
  (void) ThreadBody(NULL);

  return exitrc;
}