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oxen-core/src/common/file.cpp

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// Copyright (c) 2018-2020, The Loki Project
// Copyright (c) 2014-2019, The Monero Project
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other
// materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
// used to endorse or promote products derived from this software without specific
// prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
//
#include "file.h"
#include "epee/misc_log_ex.h"
#include <unistd.h>
#include <cstdio>
#ifdef WIN32
#include "epee/string_tools.h"
#ifndef STRSAFE_NO_DEPRECATE
#define STRSAFE_NO_DEPRECATE
#endif
#include <windows.h>
#include <shlobj.h>
#include <strsafe.h>
#else
#include <sys/file.h>
#include <sys/utsname.h>
#include <sys/stat.h>
#endif
#ifdef __GLIBC__
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <dirent.h>
#include <cstring>
#include <cctype>
#endif
#include "cryptonote_config.h"
#undef OXEN_DEFAULT_LOG_CATEGORY
#define OXEN_DEFAULT_LOG_CATEGORY "util"
namespace tools {
#ifndef _WIN32
static int flock_exnb(int fd)
{
struct flock fl;
int ret;
memset(&fl, 0, sizeof(fl));
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
fl.l_start = 0;
fl.l_len = 0;
ret = fcntl(fd, F_SETLK, &fl);
if (ret < 0)
MERROR("Error locking fd " << fd << ": " << errno << " (" << strerror(errno) << ")");
return ret;
}
#endif
private_file::private_file() noexcept : m_handle(), m_filename() {}
private_file::private_file(std::FILE* handle, fs::path filename) noexcept
: m_handle(handle), m_filename(std::move(filename)) {}
private_file private_file::create(fs::path name)
{
#ifdef WIN32
struct close_handle
{
void operator()(HANDLE handle) const noexcept
{
CloseHandle(handle);
}
};
std::unique_ptr<void, close_handle> process = nullptr;
{
HANDLE temp{};
const bool fail = OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, std::addressof(temp)) == 0;
process.reset(temp);
if (fail)
return {};
}
DWORD sid_size = 0;
GetTokenInformation(process.get(), TokenOwner, nullptr, 0, std::addressof(sid_size));
if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
return {};
std::unique_ptr<char[]> sid{new char[sid_size]};
if (!GetTokenInformation(process.get(), TokenOwner, sid.get(), sid_size, std::addressof(sid_size)))
return {};
const PSID psid = reinterpret_cast<const PTOKEN_OWNER>(sid.get())->Owner;
const DWORD daclSize =
sizeof(ACL) + sizeof(ACCESS_ALLOWED_ACE) + GetLengthSid(psid) - sizeof(DWORD);
const std::unique_ptr<char[]> dacl{new char[daclSize]};
if (!InitializeAcl(reinterpret_cast<PACL>(dacl.get()), daclSize, ACL_REVISION))
return {};
if (!AddAccessAllowedAce(reinterpret_cast<PACL>(dacl.get()), ACL_REVISION, (READ_CONTROL | FILE_GENERIC_READ | DELETE), psid))
return {};
SECURITY_DESCRIPTOR descriptor{};
if (!InitializeSecurityDescriptor(std::addressof(descriptor), SECURITY_DESCRIPTOR_REVISION))
return {};
if (!SetSecurityDescriptorDacl(std::addressof(descriptor), true, reinterpret_cast<PACL>(dacl.get()), false))
return {};
SECURITY_ATTRIBUTES attributes{sizeof(SECURITY_ATTRIBUTES), std::addressof(descriptor), false};
std::unique_ptr<void, close_handle> file{
CreateFileW(
name.c_str(),
GENERIC_WRITE, FILE_SHARE_READ,
std::addressof(attributes),
CREATE_NEW, (FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_DELETE_ON_CLOSE),
nullptr
)
};
if (file)
{
const int fd = _open_osfhandle(reinterpret_cast<intptr_t>(file.get()), 0);
if (0 <= fd)
{
file.release();
std::FILE* real_file = _fdopen(fd, "w");
if (!real_file)
{
_close(fd);
}
return {real_file, std::move(name)};
}
}
#else
const int fdr = open(name.c_str(), (O_RDONLY | O_CREAT), S_IRUSR);
if (0 <= fdr)
{
struct stat rstats = {};
if (fstat(fdr, std::addressof(rstats)) != 0)
{
close(fdr);
return {};
}
fchmod(fdr, (S_IRUSR | S_IWUSR));
const int fdw = open(name.c_str(), O_RDWR);
fchmod(fdr, rstats.st_mode);
close(fdr);
if (0 <= fdw)
{
struct stat wstats = {};
if (fstat(fdw, std::addressof(wstats)) == 0 &&
rstats.st_dev == wstats.st_dev && rstats.st_ino == wstats.st_ino &&
flock_exnb(fdw) == 0 && ftruncate(fdw, 0) == 0)
{
std::FILE* file = fdopen(fdw, "w");
if (file) return {file, std::move(name)};
}
close(fdw);
}
}
#endif
return {};
}
private_file::~private_file() noexcept
{
std::error_code ignored;
fs::remove(filename(), ignored);
}
file_locker::file_locker(const fs::path& filename)
{
#ifdef WIN32
m_fd = INVALID_HANDLE_VALUE;
m_fd = CreateFileW(filename.c_str(), GENERIC_READ, 0, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
if (m_fd != INVALID_HANDLE_VALUE)
{
OVERLAPPED ov;
memset(&ov, 0, sizeof(ov));
if (!LockFileEx(m_fd, LOCKFILE_FAIL_IMMEDIATELY | LOCKFILE_EXCLUSIVE_LOCK, 0, 1, 0, &ov))
{
MERROR("Failed to lock " << filename << ": " << std::error_code(GetLastError(), std::system_category()));
CloseHandle(m_fd);
m_fd = INVALID_HANDLE_VALUE;
}
}
else
{
MERROR("Failed to open " << filename << ": " << std::error_code(GetLastError(), std::system_category()));
}
#else
m_fd = open(filename.c_str(), O_RDWR | O_CREAT | O_CLOEXEC, 0666);
if (m_fd != -1)
{
if (flock_exnb(m_fd) == -1)
{
MERROR("Failed to lock " << filename << ": " << std::strerror(errno));
close(m_fd);
m_fd = -1;
}
}
else
{
MERROR("Failed to open " << filename << ": " << std::strerror(errno));
}
#endif
}
file_locker::~file_locker()
{
if (locked())
{
#ifdef WIN32
CloseHandle(m_fd);
#else
close(m_fd);
#endif
}
}
bool file_locker::locked() const
{
#ifdef WIN32
return m_fd != INVALID_HANDLE_VALUE;
#else
return m_fd != -1;
#endif
}
#ifdef _WIN32
fs::path get_special_folder_path(int nfolder, bool iscreate)
{
WCHAR psz_path[MAX_PATH] = L"";
if (SHGetSpecialFolderPathW(NULL, psz_path, nfolder, iscreate))
{
return fs::path{psz_path};
}
LOG_ERROR("SHGetSpecialFolderPathW() failed, could not obtain requested path.");
return "";
}
#endif
// Windows < Vista: C:\Documents and Settings\Username\Application Data\...
// Windows >= Vista: C:\Users\Username\AppData\Roaming\...
// Sane OSes: ~/
static fs::path get_default_parent_dir() {
#ifdef _WIN32
return get_special_folder_path(CSIDL_COMMON_APPDATA, true);
#else
char* home = std::getenv("HOME");
return home && std::strlen(home) ? fs::u8path(home) : fs::current_path();
#endif
}
fs::path get_default_data_dir()
{
return get_default_parent_dir() / fs::u8path(cryptonote::DATA_DIRNAME);
}
fs::path get_depreciated_default_data_dir()
{
return get_default_parent_dir() / fs::u8path(cryptonote::old::DATA_DIRNAME);
}
void set_strict_default_file_permissions(bool strict)
{
#if defined(__MINGW32__) || defined(__MINGW__)
// no clue about the odd one out
#else
mode_t mode = strict ? 077 : 0;
umask(mode);
#endif
}
bool slurp_file(const fs::path& filename, std::string& contents)
{
fs::ifstream in;
in.exceptions(std::ifstream::failbit | std::ifstream::badbit);
try {
in.open(filename, std::ios::binary | std::ios::in | std::ios::ate);
contents.clear();
contents.resize(in.tellg());
in.seekg(0);
in.read(contents.data(), contents.size());
auto bytes_read = in.gcount();
if (static_cast<size_t>(bytes_read) < contents.size())
contents.resize(bytes_read);
return true;
} catch (...) {
return false;
}
}
bool dump_file(const fs::path& filename, std::string_view contents)
{
fs::ofstream out;
out.exceptions(std::ifstream::failbit | std::ifstream::badbit);
try {
out.open(filename, std::ios::binary | std::ios::out | std::ios::trunc);
out.write(contents.data(), contents.size());
return true;
} catch (...) {
return false;
}
}
}
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