/*
  Copyright (c) 2018, 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 "config.hpp"
#include "errno.hpp"
#include "fs_base_setxattr.hpp"
#include "fs_glob.hpp"
#include "fs_path.hpp"
#include "fs_statvfs_cache.hpp"
#include "num.hpp"
#include "rv.hpp"
#include "rwlock.hpp"
#include "str.hpp"
#include "ugid.hpp"

#include <fuse.h>

#include <sstream>
#include <string>
#include <vector>

#include <string.h>

static const char SECURITY_CAPABILITY[] = "security.capability";

using std::string;
using std::vector;

namespace l
{
  static
  bool
  is_attrname_security_capability(const char *attrname_)
  {
    return (strcmp(attrname_,SECURITY_CAPABILITY) == 0);
  }

  static
  void
  split_attrval(const string &attrval,
                string       &instruction,
                string       &values)
  {
    size_t offset;

    offset = attrval.find_first_of('/');
    instruction = attrval.substr(0,offset);
    if(offset != string::npos)
      values = attrval.substr(offset);
  }

  static
  int
  setxattr_srcmounts(const string     &attrval,
                     const int         flags,
                     Branches         &branches_,
                     pthread_rwlock_t &branches_lock)
  {
    const rwlock::WriteGuard wrg(&branches_lock);

    string instruction;
    string values;

    if((flags & XATTR_CREATE) == XATTR_CREATE)
      return -EEXIST;

    l::split_attrval(attrval,instruction,values);

    if(instruction == "+")
      branches_.add_end(values);
    else if(instruction == "+<")
      branches_.add_begin(values);
    else if(instruction == "+>")
      branches_.add_end(values);
    else if(instruction == "-")
      branches_.erase_fnmatch(values);
    else if(instruction == "-<")
      branches_.erase_begin();
    else if(instruction == "->")
      branches_.erase_end();
    else if(instruction == "=")
      branches_.set(values);
    else if(instruction.empty())
      branches_.set(values);
    else
      return -EINVAL;

    return 0;
  }

  static
  int
  setxattr_uint64_t(const string &attrval,
                    const int     flags,
                    uint64_t     &uint)
  {
    int rv;

    if((flags & XATTR_CREATE) == XATTR_CREATE)
      return -EEXIST;

    rv = num::to_uint64_t(attrval,uint);
    if(rv == -1)
      return -EINVAL;

    return 0;
  }

  static
  int
  setxattr_double(const string &attrval_,
                  const int     flags_,
                  double       *d_)
  {
    int rv;

    if((flags_ & XATTR_CREATE) == XATTR_CREATE)
      return -EEXIST;

    rv = num::to_double(attrval_,d_);
    if(rv == -1)
      return -EINVAL;

    return 0;
  }

  static
  int
  setxattr_time_t(const string &attrval,
                  const int     flags,
                  time_t       &time)
  {
    int rv;

    if((flags & XATTR_CREATE) == XATTR_CREATE)
      return -EEXIST;

    rv = num::to_time_t(attrval,time);
    if(rv == -1)
      return -EINVAL;

    return 0;
  }

  static
  int
  setxattr_bool(const string &attrval,
                const int     flags,
                bool         &value)
  {
    if((flags & XATTR_CREATE) == XATTR_CREATE)
      return -EEXIST;

    if(attrval == "false")
      value = false;
    else if(attrval == "true")
      value = true;
    else
      return -EINVAL;

    return 0;
  }

  static
  int
  setxattr_xattr(const string &attrval_,
                 const int     flags_,
                 int           xattr_)
  {
    if((flags_ & XATTR_CREATE) == XATTR_CREATE)
      return -EEXIST;

    if(attrval_ == "passthrough")
      xattr_ = 0;
    else if(attrval_ == "noattr")
      xattr_ = ENOATTR;
    else if(attrval_ == "nosys")
      xattr_ = ENOSYS;
    else
      return -EINVAL;

    return 0;
  }

  static
  int
  setxattr_statfs(const string         &attrval_,
                  const int             flags_,
                  Config::StatFS::Enum &enum_)
  {
    if((flags_ & XATTR_CREATE) == XATTR_CREATE)
      return -EEXIST;

    if(attrval_ == "base")
      enum_ = Config::StatFS::BASE;
    else if(attrval_ == "full")
      enum_ = Config::StatFS::FULL;
    else
      return -EINVAL;

    return 0;
  }

  static
  int
  setxattr_statfsignore(const string               &attrval_,
                        const int                   flags_,
                        Config::StatFSIgnore::Enum &enum_)
  {
    if((flags_ & XATTR_CREATE) == XATTR_CREATE)
      return -EEXIST;

    if(attrval_ == "none")
      enum_ = Config::StatFSIgnore::NONE;
    else if(attrval_ == "ro")
      enum_ = Config::StatFSIgnore::RO;
    else if(attrval_ == "nc")
      enum_ = Config::StatFSIgnore::NC;
    else
      return -EINVAL;

    return 0;
  }

  static
  int
  setxattr_controlfile_func_policy(Config       &config,
                                   const string &funcname,
                                   const string &attrval,
                                   const int     flags)
  {
    int rv;

    if((flags & XATTR_CREATE) == XATTR_CREATE)
      return -EEXIST;

    if(funcname == "open")
      config.open_cache.clear();

    rv = config.set_func_policy(funcname,attrval);
    if(rv == -1)
      return -errno;

    return 0;
  }

  static
  int
  setxattr_controlfile_category_policy(Config       &config,
                                       const string &categoryname,
                                       const string &attrval,
                                       const int     flags)
  {
    int rv;

    if((flags & XATTR_CREATE) == XATTR_CREATE)
      return -EEXIST;

    if(categoryname == "search")
      config.open_cache.clear();

    rv = config.set_category_policy(categoryname,attrval);
    if(rv == -1)
      return -errno;

    return 0;
  }

  static
  int
  setxattr_statfs_timeout(const string &attrval_,
                          const int     flags_)
  {
    int rv;
    uint64_t timeout;

    rv = l::setxattr_uint64_t(attrval_,flags_,timeout);
    if(rv >= 0)
      fs::statvfs_cache_timeout(timeout);

    return rv;
  }

  static
  int
  setxattr_controlfile_cache_attr(const string &attrval_,
                                  const int     flags_)
  {
    int rv;
    double d;

    rv = l::setxattr_double(attrval_,flags_,&d);
    if(rv >= 0)
      fuse_config_set_attr_timeout(fuse_get_context()->fuse,d);

    return rv;
  }

  static
  int
  setxattr_controlfile_cache_entry(const string &attrval_,
                                   const int     flags_)
  {
    int rv;
    double d;

    rv = l::setxattr_double(attrval_,flags_,&d);
    if(rv >= 0)
      fuse_config_set_entry_timeout(fuse_get_context()->fuse,d);

    return rv;
  }

  static
  int
  setxattr_controlfile_cache_negative_entry(const string &attrval_,
                                            const int     flags_)
  {
    int rv;
    double d;

    rv = l::setxattr_double(attrval_,flags_,&d);
    if(rv >= 0)
      fuse_config_set_negative_entry_timeout(fuse_get_context()->fuse,d);

    return rv;
  }

  static
  int
  setxattr_controlfile(Config       &config,
                       const string &attrname,
                       const string &attrval,
                       const int     flags)
  {
    vector<string> attr;

    str::split(attr,attrname,'.');

    switch(attr.size())
      {
      case 3:
        if(attr[2] == "srcmounts")
          return l::setxattr_srcmounts(attrval,
                                       flags,
                                       config.branches,
                                       config.branches_lock);
        else if(attr[2] == "branches")
          return l::setxattr_srcmounts(attrval,
                                       flags,
                                       config.branches,
                                       config.branches_lock);
        else if(attr[2] == "minfreespace")
          return l::setxattr_uint64_t(attrval,
                                      flags,
                                      config.minfreespace);
        else if(attr[2] == "moveonenospc")
          return l::setxattr_bool(attrval,
                                  flags,
                                  config.moveonenospc);
        else if(attr[2] == "dropcacheonclose")
          return l::setxattr_bool(attrval,
                                  flags,
                                  config.dropcacheonclose);
        else if(attr[2] == "symlinkify")
          return l::setxattr_bool(attrval,
                                  flags,
                                  config.symlinkify);
        else if(attr[2] == "symlinkify_timeout")
          return l::setxattr_time_t(attrval,
                                    flags,
                                    config.symlinkify_timeout);
        else if(attr[2] == "ignorepponrename")
          return l::setxattr_bool(attrval,
                                  flags,
                                  config.ignorepponrename);
        else if(attr[2] == "security_capability")
          return l::setxattr_bool(attrval,
                                  flags,
                                  config.security_capability);
        else if(attr[2] == "xattr")
          return l::setxattr_xattr(attrval,
                                   flags,
                                   config.xattr);
        else if(attr[2] == "link_cow")
          return l::setxattr_bool(attrval,
                                  flags,
                                  config.link_cow);
        else if(attr[2] == "statfs")
          return l::setxattr_statfs(attrval,
                                    flags,
                                    config.statfs);
        else if(attr[2] == "statfs_ignore")
          return l::setxattr_statfsignore(attrval,
                                          flags,
                                          config.statfs_ignore);
        else if(attr[2] == "direct_io")
          return l::setxattr_bool(attrval,
                                  flags,
                                  config.direct_io);
        break;

      case 4:
        if(attr[2] == "category")
          return l::setxattr_controlfile_category_policy(config,
                                                         attr[3],
                                                         attrval,
                                                         flags);
        else if(attr[2] == "func")
          return l::setxattr_controlfile_func_policy(config,
                                                     attr[3],
                                                     attrval,
                                                     flags);
        else if((attr[2] == "cache") && (attr[3] == "open"))
          return l::setxattr_uint64_t(attrval,
                                      flags,
                                      config.open_cache.timeout);
        else if((attr[2] == "cache") && (attr[3] == "statfs"))
          return l::setxattr_statfs_timeout(attrval,flags);
        else if((attr[2] == "cache") && (attr[3] == "attr"))
          return l::setxattr_controlfile_cache_attr(attrval,flags);
        else if((attr[2] == "cache") && (attr[3] == "entry"))
          return l::setxattr_controlfile_cache_entry(attrval,flags);
        else if((attr[2] == "cache") && (attr[3] == "negative_entry"))
          return l::setxattr_controlfile_cache_negative_entry(attrval,flags);
        break;

      default:
        break;
      }

    return -EINVAL;
  }

  static
  int
  setxattr_loop_core(const string *basepath,
                     const char   *fusepath,
                     const char   *attrname,
                     const char   *attrval,
                     const size_t  attrvalsize,
                     const int     flags,
                     const int     error)
  {
    int rv;
    string fullpath;

    fullpath = fs::path::make(basepath,fusepath);

    rv = fs::lsetxattr(fullpath,attrname,attrval,attrvalsize,flags);

    return error::calc(rv,error,errno);
  }

  static
  int
  setxattr_loop(const vector<const string*> &basepaths,
                const char                  *fusepath,
                const char                  *attrname,
                const char                  *attrval,
                const size_t                 attrvalsize,
                const int                    flags)
  {
    int error;

    error = -1;
    for(size_t i = 0, ei = basepaths.size(); i != ei; i++)
      {
        error = l::setxattr_loop_core(basepaths[i],fusepath,
                                      attrname,attrval,attrvalsize,flags,
                                      error);
      }

    return -error;
  }

  static
  int
  setxattr(Policy::Func::Action  actionFunc,
           const Branches       &branches_,
           const uint64_t        minfreespace,
           const char           *fusepath,
           const char           *attrname,
           const char           *attrval,
           const size_t          attrvalsize,
           const int             flags)
  {
    int rv;
    vector<const string*> basepaths;

    rv = actionFunc(branches_,fusepath,minfreespace,basepaths);
    if(rv == -1)
      return -errno;

    return l::setxattr_loop(basepaths,fusepath,attrname,attrval,attrvalsize,flags);
  }
}

namespace FUSE
{
  int
  setxattr(const char *fusepath,
           const char *attrname,
           const char *attrval,
           size_t      attrvalsize,
           int         flags)
  {
    const fuse_context *fc     = fuse_get_context();
    const Config       &config = Config::get(fc);

    if(fusepath == config.controlfile)
      return l::setxattr_controlfile(Config::get_writable(),
                                     attrname,
                                     string(attrval,attrvalsize),
                                     flags);

    if((config.security_capability == false) &&
       l::is_attrname_security_capability(attrname))
      return -ENOATTR;

    if(config.xattr)
      return -config.xattr;

    const ugid::Set         ugid(fc->uid,fc->gid);
    const rwlock::ReadGuard readlock(&config.branches_lock);

    return l::setxattr(config.setxattr,
                       config.branches,
                       config.minfreespace,
                       fusepath,
                       attrname,
                       attrval,
                       attrvalsize,
                       flags);
  }
}