libs/filesystem/src/unique_path.cpp
// filesystem unique_path.cpp --------------------------------------------------------//
// Copyright Beman Dawes 2010
// Copyright Andrey Semashev 2020
// Distributed under the Boost Software License, Version 1.0.
// See http://www.boost.org/LICENSE_1_0.txt
// Library home page: http://www.boost.org/libs/filesystem
//--------------------------------------------------------------------------------------//
#include "platform_config.hpp"
#include <boost/predef/library/c/cloudabi.h>
#include <boost/predef/os/bsd/open.h>
#include <boost/predef/os/bsd/free.h>
#ifdef BOOST_POSIX_API
#include <cerrno>
#include <stddef.h>
#include <fcntl.h>
#ifdef BOOST_HAS_UNISTD_H
#include <unistd.h>
#endif
#if !defined(BOOST_FILESYSTEM_DISABLE_ARC4RANDOM)
#if BOOST_OS_BSD_OPEN >= BOOST_VERSION_NUMBER(2, 1, 0) || \
BOOST_OS_BSD_FREE >= BOOST_VERSION_NUMBER(8, 0, 0) || \
BOOST_LIB_C_CLOUDABI
#include <stdlib.h>
#define BOOST_FILESYSTEM_HAS_ARC4RANDOM
#endif
#endif // !defined(BOOST_FILESYSTEM_DISABLE_ARC4RANDOM)
#if !defined(BOOST_FILESYSTEM_DISABLE_GETRANDOM)
#if (defined(__linux__) || defined(__linux) || defined(linux)) && \
(!defined(__ANDROID__) || __ANDROID_API__ >= 28)
#include <sys/syscall.h>
#if defined(SYS_getrandom)
#define BOOST_FILESYSTEM_HAS_GETRANDOM_SYSCALL
#endif // defined(SYS_getrandom)
#if defined(__has_include)
#if __has_include(<sys/random.h>)
#define BOOST_FILESYSTEM_HAS_GETRANDOM
#endif
#elif defined(__GLIBC__)
#if __GLIBC_PREREQ(2, 25)
#define BOOST_FILESYSTEM_HAS_GETRANDOM
#endif
#endif // BOOST_FILESYSTEM_HAS_GETRANDOM definition
#if defined(BOOST_FILESYSTEM_HAS_GETRANDOM)
#include <sys/random.h>
#endif
#endif // (defined(__linux__) || defined(__linux) || defined(linux)) && (!defined(__ANDROID__) || __ANDROID_API__ >= 28)
#endif // !defined(BOOST_FILESYSTEM_DISABLE_GETRANDOM)
#include "posix_tools.hpp"
#else // BOOST_WINDOWS_API
// We use auto-linking below to help users of static builds of Boost.Filesystem to link to whatever Windows SDK library we selected.
// The dependency information is currently not exposed in CMake config files generated by Boost.Build (https://github.com/boostorg/boost_install/issues/18),
// which makes it non-trivial for users to discover the libraries they need. This feature is deprecated and may be removed in the future,
// when the situation with CMake config files improves.
// Note that the library build system is the principal source of linking the library, which must work regardless of auto-linking.
#include <boost/predef/platform.h>
#include <boost/winapi/basic_types.hpp>
#if defined(BOOST_FILESYSTEM_HAS_BCRYPT) // defined on the command line by the project
#include <boost/winapi/error_codes.hpp>
#include <boost/winapi/bcrypt.hpp>
#if !defined(BOOST_FILESYSTEM_NO_DEPRECATED) && defined(_MSC_VER)
#pragma comment(lib, "bcrypt.lib")
#endif // !defined(BOOST_FILESYSTEM_NO_DEPRECATED) && defined(_MSC_VER)
#else // defined(BOOST_FILESYSTEM_HAS_BCRYPT)
#include <boost/winapi/crypt.hpp>
#include <boost/winapi/get_last_error.hpp>
#if !defined(BOOST_FILESYSTEM_NO_DEPRECATED) && defined(_MSC_VER)
#if !defined(_WIN32_WCE)
#pragma comment(lib, "advapi32.lib")
#else
#pragma comment(lib, "coredll.lib")
#endif
#endif // !defined(BOOST_FILESYSTEM_NO_DEPRECATED) && defined(_MSC_VER)
#endif // defined(BOOST_FILESYSTEM_HAS_BCRYPT)
#endif // BOOST_POSIX_API
#include <cstddef>
#include <boost/filesystem/config.hpp>
#include <boost/filesystem/operations.hpp>
#include "private_config.hpp"
#include "atomic_tools.hpp"
#include "error_handling.hpp"
#include <boost/filesystem/detail/header.hpp> // must be the last #include
#if defined(BOOST_POSIX_API)
// At least Mac OS X 10.6 and older doesn't support O_CLOEXEC
#ifndef O_CLOEXEC
#define O_CLOEXEC 0
#endif
#endif // defined(BOOST_POSIX_API)
namespace boost {
namespace filesystem {
namespace detail {
namespace {
#if defined(BOOST_POSIX_API) && !defined(BOOST_FILESYSTEM_HAS_ARC4RANDOM)
//! Fills buffer with cryptographically random data obtained from /dev/(u)random
int fill_random_dev_random(void* buf, std::size_t len)
{
int file = ::open("/dev/urandom", O_RDONLY | O_CLOEXEC);
if (file == -1)
{
file = ::open("/dev/random", O_RDONLY | O_CLOEXEC);
if (file == -1)
return errno;
}
std::size_t bytes_read = 0u;
while (bytes_read < len)
{
ssize_t n = ::read(file, buf, len - bytes_read);
if (BOOST_UNLIKELY(n == -1))
{
int err = errno;
if (err == EINTR)
continue;
close_fd(file);
return err;
}
bytes_read += n;
buf = static_cast< char* >(buf) + n;
}
close_fd(file);
return 0;
}
#if defined(BOOST_FILESYSTEM_HAS_GETRANDOM) || defined(BOOST_FILESYSTEM_HAS_GETRANDOM_SYSCALL)
typedef int fill_random_t(void* buf, std::size_t len);
//! Pointer to the implementation of fill_random.
fill_random_t* fill_random = &fill_random_dev_random;
//! Fills buffer with cryptographically random data obtained from getrandom()
int fill_random_getrandom(void* buf, std::size_t len)
{
std::size_t bytes_read = 0u;
while (bytes_read < len)
{
#if defined(BOOST_FILESYSTEM_HAS_GETRANDOM)
ssize_t n = ::getrandom(buf, len - bytes_read, 0u);
#else
ssize_t n = ::syscall(SYS_getrandom, buf, len - bytes_read, 0u);
#endif
if (BOOST_UNLIKELY(n < 0))
{
const int err = errno;
if (err == EINTR)
continue;
if (err == ENOSYS && bytes_read == 0u)
{
filesystem::detail::atomic_store_relaxed(fill_random, &fill_random_dev_random);
return fill_random_dev_random(buf, len);
}
return err;
}
bytes_read += n;
buf = static_cast< char* >(buf) + n;
}
return 0;
}
#endif // defined(BOOST_FILESYSTEM_HAS_GETRANDOM) || defined(BOOST_FILESYSTEM_HAS_GETRANDOM_SYSCALL)
#endif // defined(BOOST_POSIX_API) && !defined(BOOST_FILESYSTEM_HAS_ARC4RANDOM)
void system_crypt_random(void* buf, std::size_t len, boost::system::error_code* ec)
{
#if defined(BOOST_POSIX_API)
#if defined(BOOST_FILESYSTEM_HAS_GETRANDOM) || defined(BOOST_FILESYSTEM_HAS_GETRANDOM_SYSCALL)
int err = filesystem::detail::atomic_load_relaxed(fill_random)(buf, len);
if (BOOST_UNLIKELY(err != 0))
emit_error(err, ec, "boost::filesystem::unique_path");
#elif defined(BOOST_FILESYSTEM_HAS_ARC4RANDOM)
arc4random_buf(buf, len);
#else
int err = fill_random_dev_random(buf, len);
if (BOOST_UNLIKELY(err != 0))
emit_error(err, ec, "boost::filesystem::unique_path");
#endif
#else // defined(BOOST_POSIX_API)
#if defined(BOOST_FILESYSTEM_HAS_BCRYPT)
boost::winapi::BCRYPT_ALG_HANDLE_ handle;
boost::winapi::NTSTATUS_ status = boost::winapi::BCryptOpenAlgorithmProvider(&handle, boost::winapi::BCRYPT_RNG_ALGORITHM_, NULL, 0);
if (BOOST_UNLIKELY(status != 0))
{
fail:
emit_error(translate_ntstatus(status), ec, "boost::filesystem::unique_path");
return;
}
status = boost::winapi::BCryptGenRandom(handle, static_cast< boost::winapi::PUCHAR_ >(buf), static_cast< boost::winapi::ULONG_ >(len), 0);
boost::winapi::BCryptCloseAlgorithmProvider(handle, 0);
if (BOOST_UNLIKELY(status != 0))
goto fail;
#else // defined(BOOST_FILESYSTEM_HAS_BCRYPT)
boost::winapi::HCRYPTPROV_ handle;
boost::winapi::DWORD_ err = 0u;
if (BOOST_UNLIKELY(!boost::winapi::CryptAcquireContextW(&handle, NULL, NULL, boost::winapi::PROV_RSA_FULL_, boost::winapi::CRYPT_VERIFYCONTEXT_ | boost::winapi::CRYPT_SILENT_)))
{
err = boost::winapi::GetLastError();
fail:
emit_error(err, ec, "boost::filesystem::unique_path");
return;
}
boost::winapi::BOOL_ gen_ok = boost::winapi::CryptGenRandom(handle, static_cast< boost::winapi::DWORD_ >(len), static_cast< boost::winapi::BYTE_* >(buf));
if (BOOST_UNLIKELY(!gen_ok))
err = boost::winapi::GetLastError();
boost::winapi::CryptReleaseContext(handle, 0);
if (BOOST_UNLIKELY(!gen_ok))
goto fail;
#endif // defined(BOOST_FILESYSTEM_HAS_BCRYPT)
#endif // defined(BOOST_POSIX_API)
}
#ifdef BOOST_WINDOWS_API
BOOST_CONSTEXPR_OR_CONST wchar_t hex[] = L"0123456789abcdef";
BOOST_CONSTEXPR_OR_CONST wchar_t percent = L'%';
#else
BOOST_CONSTEXPR_OR_CONST char hex[] = "0123456789abcdef";
BOOST_CONSTEXPR_OR_CONST char percent = '%';
#endif
} // unnamed namespace
#if defined(linux) || defined(__linux) || defined(__linux__)
//! Initializes fill_random implementation pointer
void init_fill_random_impl(unsigned int major_ver, unsigned int minor_ver, unsigned int patch_ver)
{
#if defined(BOOST_FILESYSTEM_HAS_INIT_PRIORITY) && \
(defined(BOOST_FILESYSTEM_HAS_GETRANDOM) || defined(BOOST_FILESYSTEM_HAS_GETRANDOM_SYSCALL))
fill_random_t* fr = &fill_random_dev_random;
if (major_ver > 3u || (major_ver == 3u && minor_ver >= 17u))
fr = &fill_random_getrandom;
filesystem::detail::atomic_store_relaxed(fill_random, fr);
#endif
}
#endif // defined(linux) || defined(__linux) || defined(__linux__)
BOOST_FILESYSTEM_DECL
path unique_path(path const& model, system::error_code* ec)
{
// This function used wstring for fear of misidentifying
// a part of a multibyte character as a percent sign.
// However, double byte encodings only have 80-FF as lead
// bytes and 40-7F as trailing bytes, whereas % is 25.
// So, use string on POSIX and avoid conversions.
path::string_type s(model.native());
char ran[16] = {}; // init to avoid clang static analyzer message
// see ticket #8954
BOOST_CONSTEXPR_OR_CONST unsigned int max_nibbles = 2u * sizeof(ran); // 4-bits per nibble
unsigned int nibbles_used = max_nibbles;
for (path::string_type::size_type i = 0, n = s.size(); i < n; ++i)
{
if (s[i] == percent) // digit request
{
if (nibbles_used == max_nibbles)
{
system_crypt_random(ran, sizeof(ran), ec);
if (ec && *ec)
return path();
nibbles_used = 0;
}
unsigned int c = ran[nibbles_used / 2u];
c >>= 4u * (nibbles_used++ & 1u); // if odd, shift right 1 nibble
s[i] = hex[c & 0xf]; // convert to hex digit and replace
}
}
if (ec)
ec->clear();
return s;
}
} // namespace detail
} // namespace filesystem
} // namespace boost
#include <boost/filesystem/detail/footer.hpp>