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transmission/libtransmission/file-posix.cc

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// This file Copyright © 2013-2023 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#undef _GNU_SOURCE
#define _GNU_SOURCE // NOLINT
#include <algorithm>
#include <array>
#include <cerrno>
#include <climits> /* PATH_MAX */
#include <cstdint> /* SIZE_MAX */
#include <cstdio>
#include <string_view>
#include <string>
#include <vector>
#include <dirent.h>
#include <fcntl.h> /* O_LARGEFILE, posix_fadvise(), [posix_]fallocate(), fcntl() */
#include <libgen.h> /* basename(), dirname() */
#include <sys/file.h> /* flock() */
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h> /* lseek(), write(), ftruncate(), pread(), pwrite(), pathconf(), etc */
#ifdef HAVE_XFS_XFS_H
#include <xfs/xfs.h>
#endif
/* OS-specific file copy (copy_file_range, sendfile64, or copyfile). */
#if defined(__linux__)
#include <linux/version.h>
/* Linux's copy_file_range(2) is buggy prior to 5.3. */
#if defined(HAVE_COPY_FILE_RANGE) && LINUX_VERSION_CODE >= KERNEL_VERSION(5, 3, 0)
#define USE_COPY_FILE_RANGE
#elif defined(HAVE_SENDFILE64)
#include <sys/sendfile.h>
#define USE_SENDFILE64
#endif
#elif defined(__APPLE__) && defined(HAVE_COPYFILE)
#include <copyfile.h>
#ifndef COPYFILE_CLONE /* macos < 10.12 */
#define COPYFILE_CLONE 0
#endif
#define USE_COPYFILE
#elif defined(HAVE_COPY_FILE_RANGE)
/* Presently this is only FreeBSD 13+. */
#define USE_COPY_FILE_RANGE
#endif /* __linux__ */
#include <fmt/core.h>
#include "libtransmission/transmission.h"
#include "libtransmission/error.h"
#include "libtransmission/file.h"
#include "libtransmission/log.h"
#include "libtransmission/tr-assert.h"
#include "libtransmission/tr-strbuf.h"
#ifndef O_LARGEFILE
#define O_LARGEFILE 0
#endif
#ifndef O_BINARY
#define O_BINARY 0
#endif
#ifndef O_SEQUENTIAL
#define O_SEQUENTIAL 0
#endif
#ifndef O_CLOEXEC
#define O_CLOEXEC 0
#endif
#ifndef PATH_MAX
#define PATH_MAX 4096
#endif
/* don't use pread/pwrite on old versions of uClibc because they're buggy.
* https://trac.transmissionbt.com/ticket/3826 */
#if defined(__UCLIBC__) && !TR_UCLIBC_CHECK_VERSION(0, 9, 28)
#undef HAVE_PREAD
#undef HAVE_PWRITE
#endif
#ifdef __APPLE__
#ifndef HAVE_PREAD
#define HAVE_PREAD
#endif
#ifndef HAVE_PWRITE
#define HAVE_PWRITE
#endif
#ifndef HAVE_MKDTEMP
#define HAVE_MKDTEMP
#endif
#endif
using namespace std::literals;
namespace
{
void set_system_error_if_file_found(tr_error** error, int code)
{
if (code != ENOENT)
{
tr_error_set_from_errno(error, code);
}
}
void set_file_for_single_pass(tr_sys_file_t handle)
{
/* Set hints about the lookahead buffer and caching. It's okay
for these to fail silently, so don't let them affect errno */
int const err = errno;
if (handle == TR_BAD_SYS_FILE)
{
return;
}
#ifdef HAVE_POSIX_FADVISE
(void)posix_fadvise(handle, 0, 0, POSIX_FADV_SEQUENTIAL);
#endif
#ifdef __APPLE__
(void)fcntl(handle, F_RDAHEAD, 1);
(void)fcntl(handle, F_NOCACHE, 1);
#endif
errno = err;
}
} // namespace
bool tr_sys_path_exists(char const* path, tr_error** error)
{
TR_ASSERT(path != nullptr);
bool const ret = access(path, F_OK) != -1;
if (!ret)
{
set_system_error_if_file_found(error, errno);
}
return ret;
}
std::optional<tr_sys_path_info> tr_sys_path_get_info(std::string_view path, int flags, tr_error** error)
{
struct stat sb = {};
bool ok = false;
auto const szpath = tr_pathbuf{ path };
if ((flags & TR_SYS_PATH_NO_FOLLOW) == 0)
{
ok = stat(szpath, &sb) != -1;
}
else
{
ok = lstat(szpath, &sb) != -1;
}
if (!ok)
{
tr_error_set_from_errno(error, errno);
return {};
}
auto info = tr_sys_path_info{};
if (S_ISREG(sb.st_mode))
{
info.type = TR_SYS_PATH_IS_FILE;
}
else if (S_ISDIR(sb.st_mode))
{
info.type = TR_SYS_PATH_IS_DIRECTORY;
}
else
{
info.type = TR_SYS_PATH_IS_OTHER;
}
info.size = static_cast<uint64_t>(sb.st_size);
info.last_modified_at = sb.st_mtime;
return info;
}
bool tr_sys_path_is_relative(std::string_view path)
{
return std::empty(path) || path.front() != '/';
}
bool tr_sys_path_is_same(char const* path1, char const* path2, tr_error** error)
{
TR_ASSERT(path1 != nullptr);
TR_ASSERT(path2 != nullptr);
bool ret = false;
struct stat sb1 = {};
struct stat sb2 = {};
if (stat(path1, &sb1) != -1 && stat(path2, &sb2) != -1)
{
ret = sb1.st_dev == sb2.st_dev && sb1.st_ino == sb2.st_ino;
}
else
{
set_system_error_if_file_found(error, errno);
}
return ret;
}
std::string tr_sys_path_resolve(std::string_view path, tr_error** error)
{
auto const szpath = tr_pathbuf{ path };
auto buf = std::array<char, PATH_MAX>{};
if (auto const* const ret = realpath(szpath, std::data(buf)); ret != nullptr)
{
return ret;
}
tr_error_set_from_errno(error, errno);
return {};
}
std::string_view tr_sys_path_basename(std::string_view path, tr_error** /*error*/)
{
// As per the basename() manpage:
// If path [is] an empty string, then basename() return[s] the string "."
if (std::empty(path))
{
return "."sv;
}
// Remove all trailing slashes.
// If nothing is left, return "/"
if (auto pos = path.find_last_not_of('/'); pos != std::string_view::npos)
{
path = path.substr(0, pos + 1);
}
else // all slashes
{
return "/"sv;
}
if (auto pos = path.find_last_of('/'); pos != std::string_view::npos)
{
path.remove_prefix(pos + 1);
}
return std::empty(path) ? "/"sv : path;
}
// This function is adapted from Node.js's path.posix.dirname() function,
// which is copyrighted by Joyent, Inc. and other Node contributors
// and is distributed under MIT (SPDX:MIT) license.
std::string_view tr_sys_path_dirname(std::string_view path)
{
auto const len = std::size(path);
if (len == 0U)
{
return "."sv;
}
auto const has_root = path[0] == '/';
auto end = std::string_view::npos;
auto matched_slash = bool{ true };
for (auto i = len - 1; i >= 1U; --i)
{
if (path[i] == '/')
{
if (!matched_slash)
{
end = i;
break;
}
}
else
{
// We saw the first non-path separator
matched_slash = false;
}
}
if (end == std::string_view::npos)
{
return has_root ? "/"sv : "."sv;
}
if (has_root && end == 1)
{
return "//"sv;
}
return path.substr(0, end);
}
bool tr_sys_path_rename(char const* src_path, char const* dst_path, tr_error** error)
{
TR_ASSERT(src_path != nullptr);
TR_ASSERT(dst_path != nullptr);
bool const ret = rename(src_path, dst_path) != -1;
if (!ret)
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
/* We try to do a fast (in-kernel) copy using a variety of non-portable system
* calls. If the current implementation does not support in-kernel copying, we
* use a user-space fallback instead. */
bool tr_sys_path_copy(char const* src_path, char const* dst_path, tr_error** error)
{
TR_ASSERT(src_path != nullptr);
TR_ASSERT(dst_path != nullptr);
#if defined(USE_COPYFILE)
if (copyfile(src_path, dst_path, nullptr, COPYFILE_CLONE | COPYFILE_ALL) < 0)
{
tr_error_set_from_errno(error, errno);
return false;
}
return true;
#else /* USE_COPYFILE */
auto const info = tr_sys_path_get_info(src_path, 0, error);
if (!info)
{
tr_error_prefix(error, "Unable to get information on source file: ");
return false;
}
/* Other OSes require us to copy between file descriptors, so open them. */
tr_sys_file_t const in = tr_sys_file_open(src_path, TR_SYS_FILE_READ | TR_SYS_FILE_SEQUENTIAL, 0, error);
if (in == TR_BAD_SYS_FILE)
{
tr_error_prefix(error, "Unable to open source file: ");
return false;
}
tr_sys_file_t const out = tr_sys_file_open(
dst_path,
TR_SYS_FILE_WRITE | TR_SYS_FILE_CREATE | TR_SYS_FILE_TRUNCATE,
0666,
error);
if (out == TR_BAD_SYS_FILE)
{
tr_error_prefix(error, "Unable to open destination file: ");
tr_sys_file_close(in);
return false;
}
uint64_t file_size = info->size;
int errno_cpy = 0; /* keep errno intact across copy attempts */
#if defined(USE_COPY_FILE_RANGE)
/* Kernel copy by copy_file_range */
/* try this first if available, no need to check previous copy attempts */
/* might throw EXDEV when used between filesystems in most kernels */
while (file_size > 0U)
{
size_t const chunk_size = std::min({ file_size, uint64_t{ SSIZE_MAX }, uint64_t{ INT32_MAX } });
auto const copied = copy_file_range(in, nullptr, out, nullptr, chunk_size, 0);
TR_ASSERT(copied == -1 || copied >= 0); /* -1 for error; some non-negative value otherwise. */
if (copied == -1)
{
errno_cpy = errno; /* remember me for later */
if (errno != EXDEV) /* EXDEV is expected, don't log error */
{
tr_error_set_from_errno(error, errno);
}
if (file_size > 0U)
{
file_size = info->size; /* restore file_size for next fallback */
}
break; /* break copy */
}
TR_ASSERT(copied >= 0 && ((uint64_t)copied) <= file_size);
TR_ASSERT(copied >= 0 && ((uint64_t)copied) <= chunk_size);
file_size -= copied;
} /* end file_size loop */
/* at this point errno_cpy is either set or file_size is 0 due to while condition */
#endif /* USE_COPY_FILE_RANGE */
#if defined(USE_SENDFILE64)
/* Kernel copy by sendfile64 */
/* if file_size>0 and errno_cpy==0, we probably never entered any previous copy attempt, also: */
/* if we (still) got something to copy and we encountered certain error in copy_file_range */
/* duplicated code, this could be refactored in a function */
/* keeping the copy paths in blocks helps with error tracing though */
/* trying sendfile after EXDEV is more efficient than falling to user-space straight away */
if (file_size > 0U && (errno_cpy == 0 || errno_cpy == EXDEV))
{
/* set file offsets to 0 in case previous copy did move them */
/* TR_BAD_SYS_FILE has previously been checked, we can directly lseek */
/* in case we have no pending errno, be kind enough to report any error */
if (lseek(in, 0, SEEK_SET) == -1 || lseek(out, 0, SEEK_SET) == -1)
{
if (errno_cpy == 0)
{
tr_error_set_from_errno(error, errno);
}
}
else
{
while (file_size > 0U)
{
size_t const chunk_size = std::min({ file_size, uint64_t{ SSIZE_MAX }, uint64_t{ INT32_MAX } });
auto const copied = sendfile64(out, in, nullptr, chunk_size);
TR_ASSERT(copied == -1 || copied >= 0); /* -1 for error; some non-negative value otherwise. */
if (copied == -1)
{
errno_cpy = errno; /* remember me for later */
tr_error_set_from_errno(error, errno);
if (file_size > 0U)
{
file_size = info->size; /* restore file_size for next fallback */
}
break; /* break copy */
}
TR_ASSERT(copied >= 0 && ((uint64_t)copied) <= file_size);
TR_ASSERT(copied >= 0 && ((uint64_t)copied) <= chunk_size);
file_size -= copied;
} /* end file_size loop */
} /* end lseek error */
} /* end fallback check */
/* at this point errno_cpy is either set or file_size is 0 due to while condition */
#endif /* USE_SENDFILE64 */
/* Fallback to user-space copy. */
/* if file_size>0 and errno_cpy==0, we probably never entered any copy attempt, also: */
/* if we (still) got something to copy and we encountered certain error in previous attempts */
if (file_size > 0U && (errno_cpy == 0 || errno_cpy == EXDEV))
{
static auto constexpr Buflen = size_t{ 1024U * 1024U }; /* 1024 KiB buffer */
auto buf = std::vector<char>{};
buf.resize(Buflen);
/* set file offsets to 0 in case previous copy did move them */
/* TR_BAD_SYS_FILE has previously been checked, we can directly lseek */
/* in case we have no pending errno, be kind enough to report any error */
if (lseek(in, 0, SEEK_SET) == -1 || lseek(out, 0, SEEK_SET) == -1)
{
if (errno_cpy == 0)
{
tr_error_set_from_errno(error, errno);
}
}
else
{
while (file_size > 0U)
{
uint64_t const chunk_size = std::min(file_size, uint64_t{ Buflen });
uint64_t bytes_read = 0;
uint64_t bytes_written = 0;
if (!tr_sys_file_read(in, std::data(buf), chunk_size, &bytes_read, error))
{
break;
}
if (!tr_sys_file_write(out, std::data(buf), bytes_read, &bytes_written, error))
{
break;
}
TR_ASSERT(bytes_read == bytes_written);
TR_ASSERT(bytes_written <= file_size);
file_size -= bytes_written;
} /* end file_size loop */
} /* end lseek error */
} /* end fallback check */
/* all copy paths will end here, file_size>0 signifies error */
/* cleanup */
tr_sys_file_close(out);
tr_sys_file_close(in);
if (file_size != 0)
{
tr_error_prefix(error, "Unable to read/write: ");
return false;
}
return true;
#endif /* USE_COPYFILE */
}
bool tr_sys_path_remove(char const* path, tr_error** error)
{
TR_ASSERT(path != nullptr);
bool const ret = remove(path) != -1;
if (!ret)
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
char* tr_sys_path_native_separators(char* path)
{
return path;
}
tr_sys_file_t tr_sys_file_get_std(tr_std_sys_file_t std_file, tr_error** error)
{
tr_sys_file_t ret = TR_BAD_SYS_FILE;
switch (std_file)
{
case TR_STD_SYS_FILE_IN:
ret = STDIN_FILENO;
break;
case TR_STD_SYS_FILE_OUT:
ret = STDOUT_FILENO;
break;
case TR_STD_SYS_FILE_ERR:
ret = STDERR_FILENO;
break;
default:
TR_ASSERT_MSG(false, fmt::format(FMT_STRING("unknown standard file {:d}"), std_file));
tr_error_set_from_errno(error, EINVAL);
}
return ret;
}
tr_sys_file_t tr_sys_file_open(char const* path, int flags, int permissions, tr_error** error)
{
TR_ASSERT(path != nullptr);
TR_ASSERT((flags & (TR_SYS_FILE_READ | TR_SYS_FILE_WRITE)) != 0);
struct native_map_item
{
int symbolic_mask;
int symbolic_value;
int native_value;
};
auto constexpr NativeMap = std::array<native_map_item, 8>{
{ { TR_SYS_FILE_READ | TR_SYS_FILE_WRITE, TR_SYS_FILE_READ | TR_SYS_FILE_WRITE, O_RDWR },
{ TR_SYS_FILE_READ | TR_SYS_FILE_WRITE, TR_SYS_FILE_READ, O_RDONLY },
{ TR_SYS_FILE_READ | TR_SYS_FILE_WRITE, TR_SYS_FILE_WRITE, O_WRONLY },
{ TR_SYS_FILE_CREATE, TR_SYS_FILE_CREATE, O_CREAT },
{ TR_SYS_FILE_APPEND, TR_SYS_FILE_APPEND, O_APPEND },
{ TR_SYS_FILE_TRUNCATE, TR_SYS_FILE_TRUNCATE, O_TRUNC },
{ TR_SYS_FILE_SEQUENTIAL, TR_SYS_FILE_SEQUENTIAL, O_SEQUENTIAL } }
};
int native_flags = O_BINARY | O_LARGEFILE | O_CLOEXEC;
for (auto const& item : NativeMap)
{
if ((flags & item.symbolic_mask) == item.symbolic_value)
{
native_flags |= item.native_value;
}
}
tr_sys_file_t const ret = open(path, native_flags, permissions);
if (ret != TR_BAD_SYS_FILE)
{
if ((flags & TR_SYS_FILE_SEQUENTIAL) != 0)
{
set_file_for_single_pass(ret);
}
}
else
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
tr_sys_file_t tr_sys_file_open_temp(char* path_template, tr_error** error)
{
TR_ASSERT(path_template != nullptr);
tr_sys_file_t const ret = mkstemp(path_template);
if (ret == TR_BAD_SYS_FILE)
{
tr_error_set_from_errno(error, errno);
}
set_file_for_single_pass(ret);
return ret;
}
bool tr_sys_file_close(tr_sys_file_t handle, tr_error** error)
{
TR_ASSERT(handle != TR_BAD_SYS_FILE);
bool const ret = close(handle) != -1;
if (!ret)
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
bool tr_sys_file_read(tr_sys_file_t handle, void* buffer, uint64_t size, uint64_t* bytes_read, tr_error** error)
{
TR_ASSERT(handle != TR_BAD_SYS_FILE);
TR_ASSERT(buffer != nullptr || size == 0);
bool ret = false;
auto const my_bytes_read = read(handle, buffer, size);
static_assert(sizeof(*bytes_read) >= sizeof(my_bytes_read));
if (my_bytes_read != -1)
{
if (bytes_read != nullptr)
{
*bytes_read = my_bytes_read;
}
ret = true;
}
else
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
bool tr_sys_file_read_at(
tr_sys_file_t handle,
void* buffer,
uint64_t size,
uint64_t offset,
uint64_t* bytes_read,
tr_error** error)
{
TR_ASSERT(handle != TR_BAD_SYS_FILE);
TR_ASSERT(buffer != nullptr || size == 0);
/* seek requires signed offset, so it should be in mod range */
TR_ASSERT(offset < UINT64_MAX / 2);
bool ret = false;
#ifdef HAVE_PREAD
auto const my_bytes_read = pread(handle, buffer, size, offset);
#else
ssize_t const my_bytes_read = lseek(handle, offset, SEEK_SET) == -1 ? -1 : read(handle, buffer, size);
#endif
static_assert(sizeof(*bytes_read) >= sizeof(my_bytes_read));
if (my_bytes_read > 0)
{
if (bytes_read != nullptr)
{
*bytes_read = my_bytes_read;
}
ret = true;
}
else if (my_bytes_read == -1)
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
bool tr_sys_file_write(tr_sys_file_t handle, void const* buffer, uint64_t size, uint64_t* bytes_written, tr_error** error)
{
TR_ASSERT(handle != TR_BAD_SYS_FILE);
TR_ASSERT(buffer != nullptr || size == 0);
bool ret = false;
auto const my_bytes_written = write(handle, buffer, size);
static_assert(sizeof(*bytes_written) >= sizeof(my_bytes_written));
if (my_bytes_written != -1)
{
if (bytes_written != nullptr)
{
*bytes_written = my_bytes_written;
}
ret = true;
}
else
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
bool tr_sys_file_write_at(
tr_sys_file_t handle,
void const* buffer,
uint64_t size,
uint64_t offset,
uint64_t* bytes_written,
tr_error** error)
{
TR_ASSERT(handle != TR_BAD_SYS_FILE);
TR_ASSERT(buffer != nullptr || size == 0);
/* seek requires signed offset, so it should be in mod range */
TR_ASSERT(offset < UINT64_MAX / 2);
bool ret = false;
#ifdef HAVE_PWRITE
auto const my_bytes_written = pwrite(handle, buffer, size, offset);
#else
ssize_t const my_bytes_written = lseek(handle, offset, SEEK_SET) == -1 ? -1 : write(handle, buffer, size);
#endif
static_assert(sizeof(*bytes_written) >= sizeof(my_bytes_written));
if (my_bytes_written != -1)
{
if (bytes_written != nullptr)
{
*bytes_written = my_bytes_written;
}
ret = true;
}
else
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
bool tr_sys_file_flush(tr_sys_file_t handle, tr_error** error)
{
TR_ASSERT(handle != TR_BAD_SYS_FILE);
bool const ret = (fsync(handle) != -1);
if (!ret)
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
bool tr_sys_file_flush_possible(tr_sys_file_t handle, tr_error** error)
{
TR_ASSERT(handle != TR_BAD_SYS_FILE);
if (struct stat statbuf = {}; fstat(handle, &statbuf) == 0)
{
return S_ISREG(statbuf.st_mode);
}
tr_error_set_from_errno(error, errno);
return false;
}
bool tr_sys_file_truncate(tr_sys_file_t handle, uint64_t size, tr_error** error)
{
TR_ASSERT(handle != TR_BAD_SYS_FILE);
bool const ret = ftruncate(handle, size) != -1;
if (!ret)
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
bool tr_sys_file_advise(
[[maybe_unused]] tr_sys_file_t handle,
[[maybe_unused]] uint64_t offset,
[[maybe_unused]] uint64_t size,
[[maybe_unused]] tr_sys_file_advice_t advice,
[[maybe_unused]] tr_error** error)
{
TR_ASSERT(handle != TR_BAD_SYS_FILE);
TR_ASSERT(size > 0);
TR_ASSERT(advice == TR_SYS_FILE_ADVICE_WILL_NEED || advice == TR_SYS_FILE_ADVICE_DONT_NEED);
bool ret = true;
#if defined(HAVE_POSIX_FADVISE)
int const native_advice = advice == TR_SYS_FILE_ADVICE_WILL_NEED ?
POSIX_FADV_WILLNEED :
(advice == TR_SYS_FILE_ADVICE_DONT_NEED ? POSIX_FADV_DONTNEED : POSIX_FADV_NORMAL);
TR_ASSERT(native_advice != POSIX_FADV_NORMAL);
if (int const code = posix_fadvise(handle, offset, size, native_advice); code != 0)
{
tr_error_set_from_errno(error, code);
ret = false;
}
#elif defined(__APPLE__)
if (advice == TR_SYS_FILE_ADVICE_WILL_NEED)
{
auto radv = radvisory{};
radv.ra_offset = offset;
radv.ra_count = size;
ret = fcntl(handle, F_RDADVISE, &radv) != -1;
if (!ret)
{
tr_error_set_from_errno(error, errno);
}
}
#endif
return ret;
}
namespace
{
#ifdef HAVE_FALLOCATE64
bool preallocate_fallocate64(tr_sys_file_t handle, uint64_t size)
{
return fallocate64(handle, 0, 0, size) == 0;
}
#endif
#ifdef HAVE_XFS_XFS_H
bool full_preallocate_xfs(tr_sys_file_t handle, uint64_t size)
{
if (platform_test_xfs_fd(handle) == 0) // true if on xfs filesystem
{
return false;
}
xfs_flock64_t fl;
fl.l_whence = 0;
fl.l_start = 0;
fl.l_len = size;
// The blocks are allocated, but not zeroed, and the file size does not change
bool ok = xfsctl(nullptr, handle, XFS_IOC_RESVSP64, &fl) != -1;
if (ok)
{
ok = ftruncate(handle, size) == 0;
}
return ok;
}
#endif
#ifdef __APPLE__
bool full_preallocate_apple(tr_sys_file_t handle, uint64_t size)
{
fstore_t fst;
fst.fst_flags = F_ALLOCATEALL;
fst.fst_posmode = F_PEOFPOSMODE;
fst.fst_offset = 0;
fst.fst_length = size;
fst.fst_bytesalloc = 0;
bool ok = fcntl(handle, F_PREALLOCATE, &fst) != -1;
if (ok)
{
ok = ftruncate(handle, size) == 0;
}
return ok;
}
#endif
#ifdef HAVE_POSIX_FALLOCATE
bool full_preallocate_posix(tr_sys_file_t handle, uint64_t size)
{
return posix_fallocate(handle, 0, size) == 0;
}
#endif
} // unnamed namespace
bool tr_sys_file_preallocate(tr_sys_file_t handle, uint64_t size, int flags, tr_error** error)
{
TR_ASSERT(handle != TR_BAD_SYS_FILE);
using prealloc_func = bool (*)(tr_sys_file_t, uint64_t);
// these approaches are fast and should be tried first
auto approaches = std::vector<prealloc_func>{
#ifdef HAVE_FALLOCATE64
preallocate_fallocate64
#endif
};
// these approaches are sometimes slower in some settings (e.g.
// a slow zeroing of all the preallocated space) so only use them
// if specified by `flags`
if ((flags & TR_SYS_FILE_PREALLOC_SPARSE) == 0)
{
// TODO: these functions haven't been reviewed in awhile.
// It's possible that some are faster now & should be promoted
// to 'always try' and/or replaced with fresher platform API.
approaches.insert(
std::end(approaches),
{
#ifdef HAVE_XFS_XFS_H
full_preallocate_xfs,
#endif
#ifdef __APPLE__
full_preallocate_apple,
#endif
#ifdef HAVE_POSIX_FALLOCATE
full_preallocate_posix,
#endif
});
}
for (auto& approach : approaches) // try until one of them works
{
errno = 0;
if (auto const success = approach(handle, size); success)
{
return success;
}
if (errno == ENOSPC) // disk full, so subsequent approaches will fail too
{
break;
}
}
tr_error_set_from_errno(error, errno);
return false;
}
bool tr_sys_file_lock([[maybe_unused]] tr_sys_file_t handle, [[maybe_unused]] int operation, tr_error** error)
{
TR_ASSERT(handle != TR_BAD_SYS_FILE);
TR_ASSERT((operation & ~(TR_SYS_FILE_LOCK_SH | TR_SYS_FILE_LOCK_EX | TR_SYS_FILE_LOCK_NB | TR_SYS_FILE_LOCK_UN)) == 0);
TR_ASSERT(
!!(operation & TR_SYS_FILE_LOCK_SH) + !!(operation & TR_SYS_FILE_LOCK_EX) + !!(operation & TR_SYS_FILE_LOCK_UN) == 1);
bool ret = false;
#if defined(F_OFD_SETLK)
struct flock fl = {};
switch (operation & (TR_SYS_FILE_LOCK_SH | TR_SYS_FILE_LOCK_EX | TR_SYS_FILE_LOCK_UN))
{
case TR_SYS_FILE_LOCK_SH:
fl.l_type = F_RDLCK;
break;
case TR_SYS_FILE_LOCK_EX:
fl.l_type = F_WRLCK;
break;
case TR_SYS_FILE_LOCK_UN:
fl.l_type = F_UNLCK;
break;
}
fl.l_whence = SEEK_SET;
do
{
ret = fcntl(handle, (operation & TR_SYS_FILE_LOCK_NB) != 0 ? F_OFD_SETLK : F_OFD_SETLKW, &fl) != -1;
} while (!ret && errno == EINTR);
if (!ret && errno == EAGAIN)
{
errno = EWOULDBLOCK;
}
#elif defined(HAVE_FLOCK)
int native_operation = 0;
if ((operation & TR_SYS_FILE_LOCK_SH) != 0)
{
native_operation |= LOCK_SH;
}
if ((operation & TR_SYS_FILE_LOCK_EX) != 0)
{
native_operation |= LOCK_EX;
}
if ((operation & TR_SYS_FILE_LOCK_NB) != 0)
{
native_operation |= LOCK_NB;
}
if ((operation & TR_SYS_FILE_LOCK_UN) != 0)
{
native_operation |= LOCK_UN;
}
do
{
ret = flock(handle, native_operation) != -1;
} while (!ret && errno == EINTR);
#else
errno = ENOSYS;
ret = false;
#endif
if (!ret)
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
std::string tr_sys_dir_get_current(tr_error** error)
{
auto buf = std::vector<char>{};
buf.resize(PATH_MAX);
for (;;)
{
if (char const* const ret = getcwd(std::data(buf), std::size(buf)); ret != nullptr)
{
return ret;
}
if (errno != ERANGE)
{
tr_error_set_from_errno(error, errno);
return {};
}
buf.resize(std::size(buf) * 2);
}
}
namespace
{
#ifndef HAVE_MKDIRP
[[nodiscard]] bool tr_mkdirp_(std::string_view path, int permissions, tr_error** error)
{
auto walk = path.find_first_not_of('/'); // walk past the root
auto subpath = tr_pathbuf{};
while (walk < std::size(path))
{
auto const end = path.find('/', walk);
subpath.assign(path.substr(0, end));
auto const info = tr_sys_path_get_info(subpath, 0);
if (info && !info->isFolder())
{
tr_error_set(error, ENOTDIR, fmt::format(FMT_STRING("File is in the way: {:s}"), path));
return false;
}
if (!info && mkdir(subpath, permissions) == -1)
{
tr_error_set_from_errno(error, errno);
return false;
}
if (end == std::string_view::npos)
{
break;
}
walk = end + 1;
}
return true;
}
#endif
} // namespace
bool tr_sys_dir_create(char const* path, int flags, int permissions, tr_error** error)
{
TR_ASSERT(path != nullptr);
bool ret = false;
tr_error* my_error = nullptr;
if ((flags & TR_SYS_DIR_CREATE_PARENTS) != 0)
{
#ifdef HAVE_MKDIRP
ret = mkdirp(path, permissions) != -1;
#else
ret = tr_mkdirp_(path, permissions, &my_error);
#endif
}
else
{
ret = mkdir(path, permissions) != -1;
}
if (!ret && errno == EEXIST)
{
if (auto const info = tr_sys_path_get_info(path); info && info->type == TR_SYS_PATH_IS_DIRECTORY)
{
tr_error_clear(&my_error);
ret = true;
}
else
{
errno = EEXIST;
}
}
if (!ret)
{
if (my_error != nullptr)
{
tr_error_propagate(error, &my_error);
}
else
{
tr_error_set_from_errno(error, errno);
}
}
return ret;
}
bool tr_sys_dir_create_temp(char* path_template, tr_error** error)
{
TR_ASSERT(path_template != nullptr);
#ifdef HAVE_MKDTEMP
bool const ret = mkdtemp(path_template) != nullptr;
#else
bool const ret = mktemp(path_template) != nullptr && mkdir(path_template, 0700) != -1;
#endif
if (!ret)
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
tr_sys_dir_t tr_sys_dir_open(std::string_view path, tr_error** error)
{
auto* const ret = opendir(tr_pathbuf{ path });
if (ret == nullptr)
{
tr_error_set_from_errno(error, errno);
return TR_BAD_SYS_DIR;
}
return (tr_sys_dir_t)ret;
}
char const* tr_sys_dir_read_name(tr_sys_dir_t handle, tr_error** error)
{
TR_ASSERT(handle != TR_BAD_SYS_DIR);
char const* ret = nullptr;
errno = 0;
if (auto const* const entry = readdir(static_cast<DIR*>(handle)); entry != nullptr)
{
ret = entry->d_name;
}
else if (errno != 0)
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
bool tr_sys_dir_close(tr_sys_dir_t handle, tr_error** error)
{
TR_ASSERT(handle != TR_BAD_SYS_DIR);
bool const ret = closedir(static_cast<DIR*>(handle)) != -1;
if (!ret)
{
tr_error_set_from_errno(error, errno);
}
return ret;
}
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