mergerfs/src/mergerfs.cpp

/*
  Copyright (c) 2016, Antonio SJ Musumeci <trapexit@spawn.link>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#include "fs_wait_for_mount.hpp"
#include "syslog.hpp"

#include "fs_path.hpp"
#include "fs_umount2.hpp"
#include "mergerfs.hpp"
#include "option_parser.hpp"
#include "procfs_get_name.hpp"
#include "resources.hpp"
#include "strvec.hpp"

#include "fuse_access.hpp"
#include "fuse_bmap.hpp"
#include "fuse_chmod.hpp"
#include "fuse_chown.hpp"
#include "fuse_copy_file_range.hpp"
#include "fuse_create.hpp"
#include "fuse_destroy.hpp"
#include "fuse_fallocate.hpp"
#include "fuse_fchmod.hpp"
#include "fuse_fchown.hpp"
#include "fuse_fgetattr.hpp"
#include "fuse_flock.hpp"
#include "fuse_flush.hpp"
#include "fuse_free_hide.hpp"
#include "fuse_fsync.hpp"
#include "fuse_fsyncdir.hpp"
#include "fuse_ftruncate.hpp"
#include "fuse_futimens.hpp"
#include "fuse_getattr.hpp"
#include "fuse_getxattr.hpp"
#include "fuse_init.hpp"
#include "fuse_ioctl.hpp"
#include "fuse_link.hpp"
#include "fuse_listxattr.hpp"
#include "fuse_lock.hpp"
#include "fuse_mkdir.hpp"
#include "fuse_mknod.hpp"
#include "fuse_open.hpp"
#include "fuse_opendir.hpp"
#include "fuse_poll.hpp"
#include "fuse_prepare_hide.hpp"
#include "fuse_read_buf.hpp"
#include "fuse_readdir.hpp"
#include "fuse_readdir_plus.hpp"
#include "fuse_readlink.hpp"
#include "fuse_release.hpp"
#include "fuse_releasedir.hpp"
#include "fuse_removexattr.hpp"
#include "fuse_rename.hpp"
#include "fuse_rmdir.hpp"
#include "fuse_setxattr.hpp"
#include "fuse_statfs.hpp"
#include "fuse_symlink.hpp"
#include "fuse_truncate.hpp"
#include "fuse_unlink.hpp"
#include "fuse_utimens.hpp"
#include "fuse_write.hpp"

#include "fuse.h"

#include <cstdlib>
#include <iostream>

#include <string.h>


namespace l
{
  static
  void
  get_fuse_operations(struct fuse_operations &ops_,
                      const bool              nullrw_)
  {
    ops_.access          = FUSE::access;
    ops_.bmap            = FUSE::bmap;
    ops_.chmod           = FUSE::chmod;
    ops_.chown           = FUSE::chown;
    ops_.copy_file_range = FUSE::copy_file_range;
    ops_.create          = FUSE::create;
    ops_.destroy         = FUSE::destroy;
    ops_.fallocate       = FUSE::fallocate;
    ops_.fchmod          = FUSE::fchmod;
    ops_.fchown          = FUSE::fchown;
    ops_.fgetattr        = FUSE::fgetattr;
    ops_.flock           = FUSE::flock;
    ops_.flush           = FUSE::flush;
    ops_.free_hide       = FUSE::free_hide;
    ops_.fsync           = FUSE::fsync;
    ops_.fsyncdir        = FUSE::fsyncdir;
    ops_.ftruncate       = FUSE::ftruncate;
    ops_.futimens        = FUSE::futimens;
    ops_.getattr         = FUSE::getattr;
    ops_.getxattr        = FUSE::getxattr;
    ops_.init            = FUSE::init;
    ops_.ioctl           = FUSE::ioctl;
    ops_.link            = FUSE::link;
    ops_.listxattr       = FUSE::listxattr;
    ops_.lock            = FUSE::lock;
    ops_.mkdir           = FUSE::mkdir;
    ops_.mknod           = FUSE::mknod;
    ops_.open            = FUSE::open;
    ops_.opendir         = FUSE::opendir;
    ops_.poll            = FUSE::poll;;
    ops_.prepare_hide    = FUSE::prepare_hide;
    ops_.read_buf        = (nullrw_ ? FUSE::read_buf_null : FUSE::read_buf);
    ops_.readdir         = FUSE::readdir;
    ops_.readdir_plus    = FUSE::readdir_plus;
    ops_.readlink        = FUSE::readlink;
    ops_.release         = FUSE::release;
    ops_.releasedir      = FUSE::releasedir;
    ops_.removexattr     = FUSE::removexattr;
    ops_.rename          = FUSE::rename;
    ops_.rmdir           = FUSE::rmdir;
    ops_.setxattr        = FUSE::setxattr;
    ops_.statfs          = FUSE::statfs;
    ops_.symlink         = FUSE::symlink;
    ops_.truncate        = FUSE::truncate;
    ops_.unlink          = FUSE::unlink;
    ops_.utimens         = FUSE::utimens;
    ops_.write           = (nullrw_ ? FUSE::write_null : FUSE::write);

    return;
  }

  static
  void
  setup_resources(const int scheduling_priority_)
  {
    std::srand(time(NULL));
    resources::reset_umask();
    resources::maxout_rlimit_nofile();
    resources::maxout_rlimit_fsize();
    resources::setpriority(scheduling_priority_);
  }

  static
  void
  wait_for_mount(const Config::Read &cfg_)
  {
    fs::PathVector paths;
    fs::PathVector failed;
    std::chrono::milliseconds timeout;

    paths = cfg_->branches->to_paths();

    syslog_info("Waiting %u seconds for branches to mount",
                (uint64_t)cfg_->branches_mount_timeout);

    timeout = std::chrono::milliseconds(cfg_->branches_mount_timeout * 1000);
    fs::wait_for_mount((std::string)cfg_->mountpoint,
                       paths,
                       timeout,
                       failed);
    for(auto &path : failed)
      syslog_warning("Branch %s was not mounted within timeout",
                     path.c_str());
    if(failed.size())
      syslog_warning("Continuing to mount mergerfs despite %u branches not "
                     "being different from the mountpoint filesystem",
                     failed.size());
  }

  static
  void
  lazy_umount(const std::string target_)
  {
    int rv;

    rv = fs::umount_lazy(target_);
    switch(rv)
      {
      case 0:
        syslog_notice("%s has been successfully lazily unmounted",
                      target_.c_str());
        break;
      case -EINVAL:
        syslog_notice("%s was not a mount point needing to be unmounted",
                      target_.c_str());
        break;
      default:
        syslog_error("Error unmounting %s: %d - %s",
                     target_.c_str(),
                     -rv,
                     strerror(-rv));
        break;
      }
  }

  int
  main(const int   argc_,
       char      **argv_)
  {
    Config::Read    cfg;
    Config::ErrVec  errs;
    fuse_args       args;
    fuse_operations ops;

    syslog_open();

    memset(&ops,0,sizeof(fuse_operations));

    args.argc      = argc_;
    args.argv      = argv_;
    args.allocated = 0;

    options::parse(&args,&errs);
    if(errs.size())
      {
        std::cerr << errs << std::endl;
        return 1;
      }

    if(cfg->branches_mount_timeout > 0)
      l::wait_for_mount(cfg);

    l::setup_resources(cfg->scheduling_priority);
    l::get_fuse_operations(ops,cfg->nullrw);

    if(cfg->lazy_umount_mountpoint)
      l::lazy_umount(cfg->mountpoint);

    procfs::init();

    return fuse_main(args.argc,
                     args.argv,
                     &ops);
  }
}

int
main(int    argc_,
     char **argv_)
{
  return l::main(argc_,argv_);
}