/bitcoin/src/util/fs_helpers.cpp

Source
// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-present The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <util/fs_helpers.h>

#include <bitcoin-build-config.h> // IWYU pragma: keep

#include <logging.h>
#include <sync.h>
#include <util/fs.h>
#include <util/syserror.h>

#include <cerrno>
#include <fstream>
#include <map>
#include <memory>
#include <optional>
#include <string>
#include <system_error>
#include <utility>

#ifndef WIN32
// for posix_fallocate, in cmake/introspection.cmake we check if it is present after this
#ifdef __linux__

#ifdef _POSIX_C_SOURCE
#undef _POSIX_C_SOURCE
#endif

#define _POSIX_C_SOURCE 200112L

#endif // __linux__

#include <fcntl.h>
#include <sys/resource.h>
#include <unistd.h>
#else
#include <io.h>
#include <shlobj.h>
#endif // WIN32

/** Mutex to protect dir_locks. */
static GlobalMutex cs_dir_locks;
/** A map that contains all the currently held directory locks. After
 * successful locking, these will be held here until the global destructor
 * cleans them up and thus automatically unlocks them, or ReleaseDirectoryLocks
 * is called.
 */
static std::map<std::string, std::unique_ptr<fsbridge::FileLock>> dir_locks GUARDED_BY(cs_dir_locks);
namespace util {
LockResult LockDirectory(const fs::path& directory, const fs::path& lockfile_name, bool probe_only)
{
    LOCK(cs_dir_locks);
    fs::path pathLockFile = directory / lockfile_name;

    // If a lock for this directory already exists in the map, don't try to re-lock it
    if (dir_locks.count(fs::PathToString(pathLockFile))) {
        return LockResult::Success;
    }

    // Create empty lock file if it doesn't exist.
    if (auto created{fsbridge::fopen(pathLockFile, "a")}) {
        std::fclose(created);
    } else {
        return LockResult::ErrorWrite;
    }
    auto lock = std::make_unique<fsbridge::FileLock>(pathLockFile);
    if (!lock->TryLock()) {
        LogError("Error while attempting to lock directory %s: %s\n", fs::PathToString(directory), lock->GetReason());
        return LockResult::ErrorLock;
    }
    if (!probe_only) {
        // Lock successful and we're not just probing, put it into the map
        dir_locks.emplace(fs::PathToString(pathLockFile), std::move(lock));
    }
    return LockResult::Success;
}
} // namespace util
void UnlockDirectory(const fs::path& directory, const fs::path& lockfile_name)
{
    LOCK(cs_dir_locks);
    dir_locks.erase(fs::PathToString(directory / lockfile_name));
}

void ReleaseDirectoryLocks()
{
    LOCK(cs_dir_locks);
    dir_locks.clear();
}

bool CheckDiskSpace(const fs::path& dir, uint64_t additional_bytes)
{
    constexpr uint64_t min_disk_space = 52428800; // 50 MiB

    uint64_t free_bytes_available = fs::space(dir).available;
    return free_bytes_available >= min_disk_space + additional_bytes;
}

std::streampos GetFileSize(const char* path, std::streamsize max)
{
    std::ifstream file{path, std::ios::binary};
    file.ignore(max);
    return file.gcount();
}

bool FileCommit(FILE* file)
{
    if (fflush(file) != 0) { // harmless if redundantly called
        LogPrintf("fflush failed: %s\n", SysErrorString(errno));
        return false;
    }
#ifdef WIN32
    HANDLE hFile = (HANDLE)_get_osfhandle(_fileno(file));
    if (FlushFileBuffers(hFile) == 0) {
        LogPrintf("FlushFileBuffers failed: %s\n", Win32ErrorString(GetLastError()));
        return false;
    }
#elif defined(__APPLE__) && defined(F_FULLFSYNC)
    if (fcntl(fileno(file), F_FULLFSYNC, 0) == -1) { // Manpage says "value other than -1" is returned on success
        LogPrintf("fcntl F_FULLFSYNC failed: %s\n", SysErrorString(errno));
        return false;
    }
#elif HAVE_FDATASYNC
    if (fdatasync(fileno(file)) != 0 && errno != EINVAL) { // Ignore EINVAL for filesystems that don't support sync
        LogPrintf("fdatasync failed: %s\n", SysErrorString(errno));
        return false;
    }
#else
    if (fsync(fileno(file)) != 0 && errno != EINVAL) {
        LogPrintf("fsync failed: %s\n", SysErrorString(errno));
        return false;
    }
#endif
    return true;
}

void DirectoryCommit(const fs::path& dirname)
{
#ifndef WIN32
    FILE* file = fsbridge::fopen(dirname, "r");
    if (file) {
        fsync(fileno(file));
        fclose(file);
    }
#endif
}

bool TruncateFile(FILE* file, unsigned int length)
{
#if defined(WIN32)
    return _chsize(_fileno(file), length) == 0;
#else
    return ftruncate(fileno(file), length) == 0;
#endif
}

/**
 * this function tries to raise the file descriptor limit to the requested number.
 * It returns the actual file descriptor limit (which may be more or less than nMinFD)
 */
int RaiseFileDescriptorLimit(int nMinFD)
{
#if defined(WIN32)
    return 2048;
#else
    struct rlimit limitFD;
    if (getrlimit(RLIMIT_NOFILE, &limitFD) != -1) {
        if (limitFD.rlim_cur < (rlim_t)nMinFD) {
            limitFD.rlim_cur = nMinFD;
            if (limitFD.rlim_cur > limitFD.rlim_max)
                limitFD.rlim_cur = limitFD.rlim_max;
            setrlimit(RLIMIT_NOFILE, &limitFD);
            getrlimit(RLIMIT_NOFILE, &limitFD);
        }
        return limitFD.rlim_cur;
    }
    return nMinFD; // getrlimit failed, assume it's fine
#endif
}

/**
 * this function tries to make a particular range of a file allocated (corresponding to disk space)
 * it is advisory, and the range specified in the arguments will never contain live data
 */
void AllocateFileRange(FILE* file, unsigned int offset, unsigned int length)
{
#if defined(WIN32)
    // Windows-specific version
    HANDLE hFile = (HANDLE)_get_osfhandle(_fileno(file));
    LARGE_INTEGER nFileSize;
    int64_t nEndPos = (int64_t)offset + length;
    nFileSize.u.LowPart = nEndPos & 0xFFFFFFFF;
    nFileSize.u.HighPart = nEndPos >> 32;
    SetFilePointerEx(hFile, nFileSize, 0, FILE_BEGIN);
    SetEndOfFile(hFile);
#elif defined(__APPLE__)
    // OSX specific version
    // NOTE: Contrary to other OS versions, the OSX version assumes that
    // NOTE: offset is the size of the file.
    fstore_t fst;
    fst.fst_flags = F_ALLOCATECONTIG;
    fst.fst_posmode = F_PEOFPOSMODE;
    fst.fst_offset = 0;
    fst.fst_length = length; // mac os fst_length takes the # of free bytes to allocate, not desired file size
    fst.fst_bytesalloc = 0;
    if (fcntl(fileno(file), F_PREALLOCATE, &fst) == -1) {
        fst.fst_flags = F_ALLOCATEALL;
        fcntl(fileno(file), F_PREALLOCATE, &fst);
    }
    ftruncate(fileno(file), static_cast<off_t>(offset) + length);
#else
#if defined(HAVE_POSIX_FALLOCATE)
    // Version using posix_fallocate
    off_t nEndPos = (off_t)offset + length;
    if (0 == posix_fallocate(fileno(file), 0, nEndPos)) return;
#endif
    // Fallback version
    // TODO: just write one byte per block
    static const char buf[65536] = {};
    if (fseek(file, offset, SEEK_SET)) {
        return;
    }
    while (length > 0) {
        unsigned int now = 65536;
        if (length < now)
            now = length;
        fwrite(buf, 1, now, file); // allowed to fail; this function is advisory anyway
        length -= now;
    }
#endif
}

#ifdef WIN32
fs::path GetSpecialFolderPath(int nFolder, bool fCreate)
{
    WCHAR pszPath[MAX_PATH] = L"";

    if (SHGetSpecialFolderPathW(nullptr, pszPath, nFolder, fCreate)) {
        return fs::path(pszPath);
    }

    LogPrintf("SHGetSpecialFolderPathW() failed, could not obtain requested path.\n");
    return fs::path("");
}
#endif

bool RenameOver(fs::path src, fs::path dest)
{
    std::error_code error;
    fs::rename(src, dest, error);
    return !error;
}

/**
 * Ignores exceptions thrown by create_directories if the requested directory exists.
 * Specifically handles case where path p exists, but it wasn't possible for the user to
 * write to the parent directory.
 */
bool TryCreateDirectories(const fs::path& p)
{
    try {
        return fs::create_directories(p);
    } catch (const fs::filesystem_error&) {
        if (!fs::exists(p) || !fs::is_directory(p))
            throw;
    }

    // create_directories didn't create the directory, it had to have existed already
    return false;
}

std::string PermsToSymbolicString(fs::perms p)
{
    std::string perm_str(9, '-');

    auto set_perm = [&](size_t pos, fs::perms required_perm, char letter) {
        if ((p & required_perm) != fs::perms::none) {
            perm_str[pos] = letter;
        }
    };

    set_perm(0, fs::perms::owner_read,   'r');
    set_perm(1, fs::perms::owner_write,  'w');
    set_perm(2, fs::perms::owner_exec,   'x');
    set_perm(3, fs::perms::group_read,   'r');
    set_perm(4, fs::perms::group_write,  'w');
    set_perm(5, fs::perms::group_exec,   'x');
    set_perm(6, fs::perms::others_read,  'r');
    set_perm(7, fs::perms::others_write, 'w');
    set_perm(8, fs::perms::others_exec,  'x');

    return perm_str;
}

std::optional<fs::perms> InterpretPermString(const std::string& s)
{
    if (s == "owner") {
        return fs::perms::owner_read | fs::perms::owner_write;
    } else if (s == "group") {
        return fs::perms::owner_read | fs::perms::owner_write |
               fs::perms::group_read;
    } else if (s == "all") {
        return fs::perms::owner_read | fs::perms::owner_write |
               fs::perms::group_read |
               fs::perms::others_read;
    } else {
        return std::nullopt;
    }
}

Coverage Report

Created: 2025-06-10 13:21

Line	Count	Source
1		// Copyright (c) 2009-2010 Satoshi Nakamoto
2		// Copyright (c) 2009-present The Bitcoin Core developers
3		// Distributed under the MIT software license, see the accompanying
4		// file COPYING or http://www.opensource.org/licenses/mit-license.php.
5
6		#include <util/fs_helpers.h>
7
8		#include <bitcoin-build-config.h> // IWYU pragma: keep
9
10		#include <logging.h>
11		#include <sync.h>
12		#include <util/fs.h>
13		#include <util/syserror.h>
14
15		#include <cerrno>
16		#include <fstream>
17		#include <map>
18		#include <memory>
19		#include <optional>
20		#include <string>
21		#include <system_error>
22		#include <utility>
23
24		#ifndef WIN32
25		// for posix_fallocate, in cmake/introspection.cmake we check if it is present after this
26		#ifdef __linux__
27
28		#ifdef _POSIX_C_SOURCE
29		#undef _POSIX_C_SOURCE
30		#endif
31
32		#define _POSIX_C_SOURCE 200112L
33
34		#endif // __linux__
35
36		#include <fcntl.h>
37		#include <sys/resource.h>
38		#include <unistd.h>
39		#else
40		#include <io.h>
41		#include <shlobj.h>
42		#endif // WIN32
43
44		/** Mutex to protect dir_locks. */
45		static GlobalMutex cs_dir_locks;
46		/** A map that contains all the currently held directory locks. After
47		* successful locking, these will be held here until the global destructor
48		* cleans them up and thus automatically unlocks them, or ReleaseDirectoryLocks
49		* is called.
50		*/
51		static std::map<std::string, std::unique_ptr<fsbridge::FileLock>> dir_locks GUARDED_BY(cs_dir_locks);
52		namespace util {
53		LockResult LockDirectory(const fs::path& directory, const fs::path& lockfile_name, bool probe_only)
54	44.3k	{
55	44.3k	LOCK(cs_dir_locks);
56	44.3k	fs::path pathLockFile = directory / lockfile_name;
57
58		// If a lock for this directory already exists in the map, don't try to re-lock it
59	44.3k	if (dir_locks.count(fs::PathToString(pathLockFile))) { Branch (59:9): [True: 0, False: 44.3k]
60	0	return LockResult::Success;
61	0	}
62
63		// Create empty lock file if it doesn't exist.
64	44.3k	if (auto created{fsbridge::fopen(pathLockFile, "a")}) { Branch (64:14): [True: 44.3k, False: 0]
65	44.3k	std::fclose(created);
66	44.3k	} else {
67	0	return LockResult::ErrorWrite;
68	0	}
69	44.3k	auto lock = std::make_unique<fsbridge::FileLock>(pathLockFile);
70	44.3k	if (!lock->TryLock()) { Branch (70:9): [True: 0, False: 44.3k]
71	0	LogError("Error while attempting to lock directory %s: %s\n", fs::PathToString(directory), lock->GetReason());
72	0	return LockResult::ErrorLock;
73	0	}
74	44.3k	if (!probe_only) { Branch (74:9): [True: 22.1k, False: 22.1k]
75		// Lock successful and we're not just probing, put it into the map
76	22.1k	dir_locks.emplace(fs::PathToString(pathLockFile), std::move(lock));
77	22.1k	}
78	44.3k	return LockResult::Success;
79	44.3k	}
80		} // namespace util
81		void UnlockDirectory(const fs::path& directory, const fs::path& lockfile_name)
82	0	{
83	0	LOCK(cs_dir_locks);
84	0	dir_locks.erase(fs::PathToString(directory / lockfile_name));
85	0	}
86
87		void ReleaseDirectoryLocks()
88	0	{
89	0	LOCK(cs_dir_locks);
90	0	dir_locks.clear();
91	0	}
92
93		bool CheckDiskSpace(const fs::path& dir, uint64_t additional_bytes)
94	124k	{
95	124k	constexpr uint64_t min_disk_space = 52428800; // 50 MiB
96
97	124k	uint64_t free_bytes_available = fs::space(dir).available;
98	124k	return free_bytes_available >= min_disk_space + additional_bytes;
99	124k	}
100
101		std::streampos GetFileSize(const char* path, std::streamsize max)
102	0	{
103	0	std::ifstream file{path, std::ios::binary};
104	0	file.ignore(max);
105	0	return file.gcount();
106	0	}
107
108		bool FileCommit(FILE* file)
109	123k	{
110	123k	if (fflush(file) != 0) { // harmless if redundantly called Branch (110:9): [True: 0, False: 123k]
111	0	LogPrintf("fflush failed: %s\n", SysErrorString(errno));
112	0	return false;
113	0	}
114		#ifdef WIN32
115		HANDLE hFile = (HANDLE)_get_osfhandle(_fileno(file));
116		if (FlushFileBuffers(hFile) == 0) {
117		LogPrintf("FlushFileBuffers failed: %s\n", Win32ErrorString(GetLastError()));
118		return false;
119		}
120		#elif defined(__APPLE__) && defined(F_FULLFSYNC)
121		if (fcntl(fileno(file), F_FULLFSYNC, 0) == -1) { // Manpage says "value other than -1" is returned on success
122		LogPrintf("fcntl F_FULLFSYNC failed: %s\n", SysErrorString(errno));
123		return false;
124		}
125		#elif HAVE_FDATASYNC
126	123k	if (fdatasync(fileno(file)) != 0 && errno != EINVAL) { // Ignore EINVAL for filesystems that don't support sync Branch (126:9): [True: 0, False: 123k] Branch (126:41): [True: 0, False: 0]
127	0	LogPrintf("fdatasync failed: %s\n", SysErrorString(errno));
128	0	return false;
129	0	}
130		#else
131		if (fsync(fileno(file)) != 0 && errno != EINVAL) {
132		LogPrintf("fsync failed: %s\n", SysErrorString(errno));
133		return false;
134		}
135		#endif
136	123k	return true;
137	123k	}
138
139		void DirectoryCommit(const fs::path& dirname)
140	58.4k	{
141	58.4k	#ifndef WIN32
142	58.4k	FILE* file = fsbridge::fopen(dirname, "r");
143	58.4k	if (file) { Branch (143:9): [True: 58.4k, False: 0]
144	58.4k	fsync(fileno(file));
145	58.4k	fclose(file);
146	58.4k	}
147	58.4k	#endif
148	58.4k	}
149
150		bool TruncateFile(FILE* file, unsigned int length)
151	0	{
152		#if defined(WIN32)
153		return _chsize(_fileno(file), length) == 0;
154		#else
155	0	return ftruncate(fileno(file), length) == 0;
156	0	#endif
157	0	}
158
159		/**
160		* this function tries to raise the file descriptor limit to the requested number.
161		* It returns the actual file descriptor limit (which may be more or less than nMinFD)
162		*/
163		int RaiseFileDescriptorLimit(int nMinFD)
164	11.0k	{
165		#if defined(WIN32)
166		return 2048;
167		#else
168	11.0k	struct rlimit limitFD;
169	11.0k	if (getrlimit(RLIMIT_NOFILE, &limitFD) != -1) { Branch (169:9): [True: 11.0k, False: 0]
170	11.0k	if (limitFD.rlim_cur < (rlim_t)nMinFD) { Branch (170:13): [True: 0, False: 11.0k]
171	0	limitFD.rlim_cur = nMinFD;
172	0	if (limitFD.rlim_cur > limitFD.rlim_max) Branch (172:17): [True: 0, False: 0]
173	0	limitFD.rlim_cur = limitFD.rlim_max;
174	0	setrlimit(RLIMIT_NOFILE, &limitFD);
175	0	getrlimit(RLIMIT_NOFILE, &limitFD);
176	0	}
177	11.0k	return limitFD.rlim_cur;
178	11.0k	}
179	0	return nMinFD; // getrlimit failed, assume it's fine
180	11.0k	#endif
181	11.0k	}
182
183		/**
184		* this function tries to make a particular range of a file allocated (corresponding to disk space)
185		* it is advisory, and the range specified in the arguments will never contain live data
186		*/
187		void AllocateFileRange(FILE* file, unsigned int offset, unsigned int length)
188	33.2k	{
189		#if defined(WIN32)
190		// Windows-specific version
191		HANDLE hFile = (HANDLE)_get_osfhandle(_fileno(file));
192		LARGE_INTEGER nFileSize;
193		int64_t nEndPos = (int64_t)offset + length;
194		nFileSize.u.LowPart = nEndPos & 0xFFFFFFFF;
195		nFileSize.u.HighPart = nEndPos >> 32;
196		SetFilePointerEx(hFile, nFileSize, 0, FILE_BEGIN);
197		SetEndOfFile(hFile);
198		#elif defined(__APPLE__)
199		// OSX specific version
200		// NOTE: Contrary to other OS versions, the OSX version assumes that
201		// NOTE: offset is the size of the file.
202		fstore_t fst;
203		fst.fst_flags = F_ALLOCATECONTIG;
204		fst.fst_posmode = F_PEOFPOSMODE;
205		fst.fst_offset = 0;
206		fst.fst_length = length; // mac os fst_length takes the # of free bytes to allocate, not desired file size
207		fst.fst_bytesalloc = 0;
208		if (fcntl(fileno(file), F_PREALLOCATE, &fst) == -1) {
209		fst.fst_flags = F_ALLOCATEALL;
210		fcntl(fileno(file), F_PREALLOCATE, &fst);
211		}
212		ftruncate(fileno(file), static_cast<off_t>(offset) + length);
213		#else
214	33.2k	#if defined(HAVE_POSIX_FALLOCATE)
215		// Version using posix_fallocate
216	33.2k	off_t nEndPos = (off_t)offset + length;
217	33.2k	if (0 == posix_fallocate(fileno(file), 0, nEndPos)) return; Branch (217:9): [True: 33.2k, False: 0]
218	0	#endif
219		// Fallback version
220		// TODO: just write one byte per block
221	0	static const char buf[65536] = {};
222	0	if (fseek(file, offset, SEEK_SET)) { Branch (222:9): [True: 0, False: 0]
223	0	return;
224	0	}
225	0	while (length > 0) { Branch (225:12): [True: 0, False: 0]
226	0	unsigned int now = 65536;
227	0	if (length < now) Branch (227:13): [True: 0, False: 0]
228	0	now = length;
229	0	fwrite(buf, 1, now, file); // allowed to fail; this function is advisory anyway
230	0	length -= now;
231	0	}
232	0	#endif
233	0	}
234
235		#ifdef WIN32
236		fs::path GetSpecialFolderPath(int nFolder, bool fCreate)
237		{
238		WCHAR pszPath[MAX_PATH] = L"";
239
240		if (SHGetSpecialFolderPathW(nullptr, pszPath, nFolder, fCreate)) {
241		return fs::path(pszPath);
242		}
243
244		LogPrintf("SHGetSpecialFolderPathW() failed, could not obtain requested path.\n");
245		return fs::path("");
246		}
247		#endif
248
249		bool RenameOver(fs::path src, fs::path dest)
250	66.5k	{
251	66.5k	std::error_code error;
252	66.5k	fs::rename(src, dest, error);
253	66.5k	return !error;
254	66.5k	}
255
256		/**
257		* Ignores exceptions thrown by create_directories if the requested directory exists.
258		* Specifically handles case where path p exists, but it wasn't possible for the user to
259		* write to the parent directory.
260		*/
261		bool TryCreateDirectories(const fs::path& p)
262	44.3k	{
263	44.3k	try {
264	44.3k	return fs::create_directories(p);
265	44.3k	} catch (const fs::filesystem_error&) {
266	0	if (!fs::exists(p) \|\| !fs::is_directory(p)) Branch (266:13): [True: 0, False: 0] Branch (266:31): [True: 0, False: 0]
267	0	throw;
268	0	}
269
270		// create_directories didn't create the directory, it had to have existed already
271	0	return false;
272	44.3k	}
273
274		std::string PermsToSymbolicString(fs::perms p)
275	11.0k	{
276	11.0k	std::string perm_str(9, '-');
277
278	99.8k	auto set_perm = [&](size_t pos, fs::perms required_perm, char letter) {
279	99.8k	if ((p & required_perm) != fs::perms::none) { Branch (279:13): [True: 22.1k, False: 77.6k]
280	22.1k	perm_str[pos] = letter;
281	22.1k	}
282	99.8k	};
283
284	11.0k	set_perm(0, fs::perms::owner_read, 'r');
285	11.0k	set_perm(1, fs::perms::owner_write, 'w');
286	11.0k	set_perm(2, fs::perms::owner_exec, 'x');
287	11.0k	set_perm(3, fs::perms::group_read, 'r');
288	11.0k	set_perm(4, fs::perms::group_write, 'w');
289	11.0k	set_perm(5, fs::perms::group_exec, 'x');
290	11.0k	set_perm(6, fs::perms::others_read, 'r');
291	11.0k	set_perm(7, fs::perms::others_write, 'w');
292	11.0k	set_perm(8, fs::perms::others_exec, 'x');
293
294	11.0k	return perm_str;
295	11.0k	}
296
297		std::optional<fs::perms> InterpretPermString(const std::string& s)
298	0	{
299	0	if (s == "owner") { Branch (299:9): [True: 0, False: 0]
300	0	return fs::perms::owner_read \| fs::perms::owner_write;
301	0	} else if (s == "group") { Branch (301:16): [True: 0, False: 0]
302	0	return fs::perms::owner_read \| fs::perms::owner_write \|
303	0	fs::perms::group_read;
304	0	} else if (s == "all") { Branch (304:16): [True: 0, False: 0]
305	0	return fs::perms::owner_read \| fs::perms::owner_write \|
306	0	fs::perms::group_read \|
307	0	fs::perms::others_read;
308	0	} else {
309	0	return std::nullopt;
310	0	}
311	0	}