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// Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
// Copyright (C) 2011 Sebastian Pipping <sebastian@pipping.org>
// Copyright (C) 2016 Benjamin Barenblat <benjamin@barenblat.name>
//
// 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 3 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, see <http://www.gnu.org/licenses/>.
#define BSD_SOURCE
#define _POSIX_C_SOURCE 201602L
#include "operations.h"
#include <cerrno>
#include <cstring>
#include <memory>
#include <new>
#define FUSE_USE_VERSION 26
#include <dirent.h>
#include <fuse.h>
#include <glog/logging.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "utility.h"
namespace scoville {
namespace {
int root_fd_;
struct Directory {
DIR* fd;
dirent* entry;
off_t offset;
};
Directory* FileInfoDirectory(fuse_file_info* const file_info) {
return reinterpret_cast<Directory*>(file_info->fh);
}
mode_t DirectoryTypeToFileType(const unsigned char type) {
switch (type) {
case DT_BLK:
return S_IFBLK;
case DT_CHR:
return S_IFCHR;
case DT_DIR:
return S_IFDIR;
case DT_FIFO:
return S_IFIFO;
case DT_LNK:
return S_IFLNK;
case DT_REG:
return S_IFREG;
case DT_SOCK:
return S_IFSOCK;
default:
return 0;
}
}
#define RETURN_ON_ERROR(call) \
if ((call) == -1) { \
return -errno; \
} \
do { \
} while (false)
void* Initialize(fuse_conn_info*) {
LOG(INFO) << "initialize";
return nullptr;
}
void Destroy(void*) {
LOG(INFO) << "destroy";
LOG_IF(ERROR, close(root_fd_) == -1) << "could not close root FD: "
<< ErrnoText();
}
int Getattr(const char* const path, struct stat* output) {
LOG(INFO) << "getattr(" << path << ")";
if (path[0] == '\0') {
LOG(ERROR) << "getattr called on path not starting with /";
return -ENOENT;
}
if (strcmp(path, "/") == 0) {
// They're asking for information about the mount point.
RETURN_ON_ERROR(fstat(root_fd_, output));
return 0;
}
// Trim the leading slash so fstatat will treat it relative to root_fd_.
LOG(INFO) << "getattr: trimming leading slash";
RETURN_ON_ERROR(fstatat(root_fd_, path + 1, output, AT_SYMLINK_NOFOLLOW));
return 0;
}
int Opendir(const char* const path, fuse_file_info* const file_info) {
LOG(INFO) << "opendir(" << path << ")";
std::unique_ptr<Directory> directory;
try {
directory.reset(new Directory);
} catch (std::bad_alloc) {
return -ENOMEM;
}
if ((directory->fd = opendir(path)) == nullptr) {
return -errno;
}
directory->entry = nullptr;
directory->offset = 0;
static_assert(sizeof(file_info->fh) == sizeof(uintptr_t),
"FUSE file handles are a different size than pointers");
file_info->fh = reinterpret_cast<uintptr_t>(directory.release());
return 0;
}
int Readdir(const char*, void* const buffer, fuse_fill_dir_t filler,
const off_t offset, fuse_file_info* const file_info) {
LOG(INFO) << "readdir";
Directory* const directory = FileInfoDirectory(file_info);
if (offset != directory->offset) {
seekdir(directory->fd, offset);
directory->entry = nullptr;
directory->offset = offset;
}
while (true) {
if (!directory->entry) {
directory->entry = readdir(directory->fd);
if (!directory->entry) {
break;
}
}
struct stat stats;
std::memset(&stats, 0, sizeof(stats));
stats.st_ino = directory->entry->d_ino;
stats.st_mode = DirectoryTypeToFileType(directory->entry->d_type);
const off_t next_offset = telldir(directory->fd);
if (filler(buffer, directory->entry->d_name, &stats, next_offset)) {
break;
}
directory->entry = nullptr;
directory->offset = next_offset;
}
return 0;
}
int Releasedir(const char*, fuse_file_info* const file_info) {
LOG(INFO) << "releasedir";
Directory* const directory = FileInfoDirectory(file_info);
closedir(directory->fd);
delete directory;
return 0;
}
#undef RETURN_ON_ERROR
} // namespace
fuse_operations FuseOperations(const int root_fd) {
root_fd_ = root_fd;
fuse_operations result;
result.flag_nullpath_ok = true;
result.flag_nopath = true;
result.flag_utime_omit_ok = true;
result.init = &Initialize;
result.destroy = &Destroy;
result.getattr = &Getattr;
result.opendir = &Opendir;
result.readdir = &Readdir;
result.releasedir = &Releasedir;
return result;
}
} // namespace scoville
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