mergerfs/libfuse/lib/fuse_mt.c

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>

  This program can be distributed under the terms of the GNU LGPLv2.
  See the file COPYING.LIB.
*/

#include "fuse_i.h"
#include "fuse_misc.h"
#include "fuse_lowlevel.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <assert.h>

struct procdata
{
  struct fuse *f;
  struct fuse_chan *prevch;
  struct fuse_session *prevse;
  fuse_processor_t proc;
  void *data;
};

static void mt_session_proc(void *data, const char *buf, size_t len,
			    struct fuse_chan *ch)
{
  struct procdata *pd = (struct procdata *) data;
  struct fuse_cmd *cmd = *(struct fuse_cmd **) buf;

  (void) len;
  (void) ch;
  pd->proc(pd->f, cmd, pd->data);
}

static void mt_session_exit(void *data, int val)
{
  struct procdata *pd = (struct procdata *) data;
  if (val)
    fuse_session_exit(pd->prevse);
  else
    fuse_session_reset(pd->prevse);
}

static int mt_session_exited(void *data)
{
  struct procdata *pd = (struct procdata *) data;
  return fuse_session_exited(pd->prevse);
}

static int mt_chan_receive(struct fuse_chan **chp, char *buf, size_t size)
{
  struct fuse_cmd *cmd;
  struct procdata *pd = (struct procdata *) fuse_chan_data(*chp);

  assert(size >= sizeof(cmd));

  cmd = fuse_read_cmd(pd->f);
  if (cmd == NULL)
    return 0;

  *(struct fuse_cmd **)buf = cmd;

  return sizeof(cmd);
}

int fuse_loop_mt_proc(struct fuse *f, fuse_processor_t proc, void *data)
{
  int res;
  struct procdata pd;
  struct fuse_session *prevse = fuse_get_session(f);
  struct fuse_session *se;
  struct fuse_chan *prevch = fuse_session_next_chan(prevse, NULL);
  struct fuse_chan *ch;
  struct fuse_session_ops sop = {
    .exit = mt_session_exit,
    .exited = mt_session_exited,
    .process = mt_session_proc,
  };
  struct fuse_chan_ops cop = {
    .receive = mt_chan_receive,
  };

  pd.f = f;
  pd.prevch = prevch;
  pd.prevse = prevse;
  pd.proc = proc;
  pd.data = data;

  se = fuse_session_new(&sop, &pd);
  if (se == NULL)
    return -1;

  ch = fuse_chan_new(&cop, fuse_chan_fd(prevch),
                     sizeof(struct fuse_cmd *), &pd);
  if (ch == NULL) {
    fuse_session_destroy(se);
    return -1;
  }
  fuse_session_add_chan(se, ch);
  res = fuse_session_loop_mt(se,
                             fuse_config_num_threads(f));
  fuse_session_destroy(se);
  return res;
}

int fuse_loop_mt(struct fuse *f)
{
  if (f == NULL)
    return -1;

  int res = fuse_start_maintenance_thread(f);
  if (res)
    return -1;

  res = fuse_session_loop_mt(fuse_get_session(f),
                             fuse_config_num_threads(f));

  fuse_stop_maintenance_thread(f);

  return res;
}