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

#include <util/fs_helpers.h>

#include <sync.h>
#include <util/byte_units.h> // IWYU pragma: keep
#include <util/fs.h>
#include <util/log.h>
#include <util/syserror.h>

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

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

#ifdef __APPLE__
#include <sys/mount.h>
#include <sys/param.h>
#endif

/** 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.contains(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{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
        LogError("fflush failed: %s", SysErrorString(errno));
        return false;
    }
#ifdef WIN32
    HANDLE hFile = (HANDLE)_get_osfhandle(_fileno(file));
    if (FlushFileBuffers(hFile) == 0) {
        LogError("FlushFileBuffers failed: %s", 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
        LogError("fcntl F_FULLFSYNC failed: %s", SysErrorString(errno));
        return false;
    }
#elif HAVE_FDATASYNC
    if (fdatasync(fileno(file)) != 0 && errno != EINVAL) { // Ignore EINVAL for filesystems that don't support sync
        LogError("fdatasync failed: %s", SysErrorString(errno));
        return false;
    }
#else
    if (fsync(fileno(file)) != 0 && errno != EINVAL) {
        LogError("fsync failed: %s", 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);
    }

    LogError("SHGetSpecialFolderPathW() failed, could not obtain requested path.");
    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;
    }
}

#ifdef __APPLE__
FSType GetFilesystemType(const fs::path& path)
{
    if (struct statfs fs_info; statfs(path.c_str(), &fs_info)) {
        return FSType::ERROR;
    } else if (std::string_view{fs_info.f_fstypename} == "exfat") {
        return FSType::EXFAT;
    }
    return FSType::OTHER;
}
#endif

Coverage Report

Created: 2026-04-29 19:21

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 <bitcoin-build-config.h> // IWYU pragma: keep
7
8		#include <util/fs_helpers.h>
9
10		#include <sync.h>
11		#include <util/byte_units.h> // IWYU pragma: keep
12		#include <util/fs.h>
13		#include <util/log.h>
14		#include <util/syserror.h>
15
16		#include <cerrno>
17		#include <fstream>
18		#include <map>
19		#include <memory>
20		#include <optional>
21		#include <string>
22		#include <system_error>
23		#include <utility>
24
25		#ifndef WIN32
26		#include <fcntl.h>
27		#include <sys/resource.h>
28		#include <sys/types.h>
29		#include <unistd.h>
30		#else
31		#include <io.h>
32		#include <shlobj.h>
33		#endif // WIN32
34
35		#ifdef __APPLE__
36		#include <sys/mount.h>
37		#include <sys/param.h>
38		#endif
39
40		/** Mutex to protect dir_locks. */
41		static GlobalMutex cs_dir_locks;
42		/** A map that contains all the currently held directory locks. After
43		* successful locking, these will be held here until the global destructor
44		* cleans them up and thus automatically unlocks them, or ReleaseDirectoryLocks
45		* is called.
46		*/
47		static std::map<std::string, std::unique_ptr<fsbridge::FileLock>> dir_locks GUARDED_BY(cs_dir_locks);
48		namespace util {
49		LockResult LockDirectory(const fs::path& directory, const fs::path& lockfile_name, bool probe_only)
50	4.47k	{
51	4.47k	LOCK(cs_dir_locks);
52	4.47k	fs::path pathLockFile = directory / lockfile_name;
53
54		// If a lock for this directory already exists in the map, don't try to re-lock it
55	4.47k	if (dir_locks.contains(fs::PathToString(pathLockFile))) {
56	2	return LockResult::Success;
57	2	}
58
59		// Create empty lock file if it doesn't exist.
60	4.47k	if (auto created{fsbridge::fopen(pathLockFile, "a")}) {
61	4.46k	std::fclose(created);
62	4.46k	} else {
63	2	return LockResult::ErrorWrite;
64	2	}
65	4.46k	auto lock = std::make_unique<fsbridge::FileLock>(pathLockFile);
66	4.46k	if (!lock->TryLock()) {
67	4	LogError("Error while attempting to lock directory %s: %s\n", fs::PathToString(directory), lock->GetReason());
68	4	return LockResult::ErrorLock;
69	4	}
70	4.46k	if (!probe_only) {
71		// Lock successful and we're not just probing, put it into the map
72	2.23k	dir_locks.emplace(fs::PathToString(pathLockFile), std::move(lock));
73	2.23k	}
74	4.46k	return LockResult::Success;
75	4.46k	}
76		} // namespace util
77		void UnlockDirectory(const fs::path& directory, const fs::path& lockfile_name)
78	0	{
79	0	LOCK(cs_dir_locks);
80	0	dir_locks.erase(fs::PathToString(directory / lockfile_name));
81	0	}
82
83		void ReleaseDirectoryLocks()
84	3	{
85	3	LOCK(cs_dir_locks);
86	3	dir_locks.clear();
87	3	}
88
89		bool CheckDiskSpace(const fs::path& dir, uint64_t additional_bytes)
90	10.0k	{
91	10.0k	constexpr uint64_t min_disk_space{50_MiB};
92
93	10.0k	uint64_t free_bytes_available = fs::space(dir).available;
94	10.0k	return free_bytes_available >= min_disk_space + additional_bytes;
95	10.0k	}
96
97		std::streampos GetFileSize(const char* path, std::streamsize max)
98	0	{
99	0	std::ifstream file{path, std::ios::binary};
100	0	file.ignore(max);
101	0	return file.gcount();
102	0	}
103
104		bool FileCommit(FILE* file)
105	9.24k	{
106	9.24k	if (fflush(file) != 0) { // harmless if redundantly called
107	0	LogError("fflush failed: %s", SysErrorString(errno));
108	0	return false;
109	0	}
110		#ifdef WIN32
111		HANDLE hFile = (HANDLE)_get_osfhandle(_fileno(file));
112		if (FlushFileBuffers(hFile) == 0) {
113		LogError("FlushFileBuffers failed: %s", Win32ErrorString(GetLastError()));
114		return false;
115		}
116		#elif defined(__APPLE__) && defined(F_FULLFSYNC)
117		if (fcntl(fileno(file), F_FULLFSYNC, 0) == -1) { // Manpage says "value other than -1" is returned on success
118		LogError("fcntl F_FULLFSYNC failed: %s", SysErrorString(errno));
119		return false;
120		}
121		#elif HAVE_FDATASYNC
122	9.24k	if (fdatasync(fileno(file)) != 0 && errno != EINVAL) { // Ignore EINVAL for filesystems that don't support sync
123	0	LogError("fdatasync failed: %s", SysErrorString(errno));
124	0	return false;
125	0	}
126		#else
127		if (fsync(fileno(file)) != 0 && errno != EINVAL) {
128		LogError("fsync failed: %s", SysErrorString(errno));
129		return false;
130		}
131		#endif
132	9.24k	return true;
133	9.24k	}
134
135		void DirectoryCommit(const fs::path& dirname)
136	6.74k	{
137	6.74k	#ifndef WIN32
138	6.74k	FILE* file = fsbridge::fopen(dirname, "r");
139	6.74k	if (file) {
140	6.74k	fsync(fileno(file));
141	6.74k	fclose(file);
142	6.74k	}
143	6.74k	#endif
144	6.74k	}
145
146		bool TruncateFile(FILE* file, unsigned int length)
147	64	{
148		#if defined(WIN32)
149		return _chsize(_fileno(file), length) == 0;
150		#else
151	64	return ftruncate(fileno(file), length) == 0;
152	64	#endif
153	64	}
154
155		/**
156		* this function tries to raise the file descriptor limit to the requested number.
157		* It returns the actual file descriptor limit (which may be more or less than nMinFD)
158		*/
159		int RaiseFileDescriptorLimit(int nMinFD)
160	1.79k	{
161		#if defined(WIN32)
162		return 2048;
163		#else
164	1.79k	struct rlimit limitFD;
165	1.79k	if (getrlimit(RLIMIT_NOFILE, &limitFD) != -1) {
166	1.79k	if (limitFD.rlim_cur < (rlim_t)nMinFD) {
167	0	limitFD.rlim_cur = nMinFD;
168	0	if (limitFD.rlim_cur > limitFD.rlim_max)
169	0	limitFD.rlim_cur = limitFD.rlim_max;
170	0	setrlimit(RLIMIT_NOFILE, &limitFD);
171	0	getrlimit(RLIMIT_NOFILE, &limitFD);
172	0	}
173	1.79k	return limitFD.rlim_cur;
174	1.79k	}
175	0	return nMinFD; // getrlimit failed, assume it's fine
176	1.79k	#endif
177	1.79k	}
178
179		/**
180		* this function tries to make a particular range of a file allocated (corresponding to disk space)
181		* it is advisory, and the range specified in the arguments will never contain live data
182		*/
183		void AllocateFileRange(FILE* file, unsigned int offset, unsigned int length)
184	950	{
185		#if defined(WIN32)
186		// Windows-specific version
187		HANDLE hFile = (HANDLE)_get_osfhandle(_fileno(file));
188		LARGE_INTEGER nFileSize;
189		int64_t nEndPos = (int64_t)offset + length;
190		nFileSize.u.LowPart = nEndPos & 0xFFFFFFFF;
191		nFileSize.u.HighPart = nEndPos >> 32;
192		SetFilePointerEx(hFile, nFileSize, 0, FILE_BEGIN);
193		SetEndOfFile(hFile);
194		#elif defined(__APPLE__)
195		// OSX specific version
196		// NOTE: Contrary to other OS versions, the OSX version assumes that
197		// NOTE: offset is the size of the file.
198		fstore_t fst;
199		fst.fst_flags = F_ALLOCATECONTIG;
200		fst.fst_posmode = F_PEOFPOSMODE;
201		fst.fst_offset = 0;
202		fst.fst_length = length; // mac os fst_length takes the # of free bytes to allocate, not desired file size
203		fst.fst_bytesalloc = 0;
204		if (fcntl(fileno(file), F_PREALLOCATE, &fst) == -1) {
205		fst.fst_flags = F_ALLOCATEALL;
206		fcntl(fileno(file), F_PREALLOCATE, &fst);
207		}
208		ftruncate(fileno(file), static_cast<off_t>(offset) + length);
209		#else
210	950	#if defined(HAVE_POSIX_FALLOCATE)
211		// Version using posix_fallocate
212	950	off_t nEndPos = (off_t)offset + length;
213	950	if (0 == posix_fallocate(fileno(file), 0, nEndPos)) return;
214	0	#endif
215		// Fallback version
216		// TODO: just write one byte per block
217	0	static const char buf[65536] = {};
218	0	if (fseek(file, offset, SEEK_SET)) {
219	0	return;
220	0	}
221	0	while (length > 0) {
222	0	unsigned int now = 65536;
223	0	if (length < now)
224	0	now = length;
225	0	fwrite(buf, 1, now, file); // allowed to fail; this function is advisory anyway
226	0	length -= now;
227	0	}
228	0	#endif
229	0	}
230
231		#ifdef WIN32
232		fs::path GetSpecialFolderPath(int nFolder, bool fCreate)
233		{
234		WCHAR pszPath[MAX_PATH] = L"";
235
236		if (SHGetSpecialFolderPathW(nullptr, pszPath, nFolder, fCreate)) {
237		return fs::path(pszPath);
238		}
239
240		LogError("SHGetSpecialFolderPathW() failed, could not obtain requested path.");
241		return fs::path("");
242		}
243		#endif
244
245		bool RenameOver(fs::path src, fs::path dest)
246	4.85k	{
247	4.85k	std::error_code error;
248	4.85k	fs::rename(src, dest, error);
249	4.85k	return !error;
250	4.85k	}
251
252		/**
253		* Ignores exceptions thrown by create_directories if the requested directory exists.
254		* Specifically handles case where path p exists, but it wasn't possible for the user to
255		* write to the parent directory.
256		*/
257		bool TryCreateDirectories(const fs::path& p)
258	4.16k	{
259	4.16k	try {
260	4.16k	return fs::create_directories(p);
261	4.16k	} catch (const fs::filesystem_error&) {
262	2	if (!fs::exists(p) \|\| !fs::is_directory(p))
263	2	throw;
264	2	}
265
266		// create_directories didn't create the directory, it had to have existed already
267	0	return false;
268	4.16k	}
269
270		std::string PermsToSymbolicString(fs::perms p)
271	1.09k	{
272	1.09k	std::string perm_str(9, '-');
273
274	9.81k	auto set_perm = [&](size_t pos, fs::perms required_perm, char letter) {
275	9.81k	if ((p & required_perm) != fs::perms::none) {
276	2.18k	perm_str[pos] = letter;
277	2.18k	}
278	9.81k	};
279
280	1.09k	set_perm(0, fs::perms::owner_read, 'r');
281	1.09k	set_perm(1, fs::perms::owner_write, 'w');
282	1.09k	set_perm(2, fs::perms::owner_exec, 'x');
283	1.09k	set_perm(3, fs::perms::group_read, 'r');
284	1.09k	set_perm(4, fs::perms::group_write, 'w');
285	1.09k	set_perm(5, fs::perms::group_exec, 'x');
286	1.09k	set_perm(6, fs::perms::others_read, 'r');
287	1.09k	set_perm(7, fs::perms::others_write, 'w');
288	1.09k	set_perm(8, fs::perms::others_exec, 'x');
289
290	1.09k	return perm_str;
291	1.09k	}
292
293		std::optional<fs::perms> InterpretPermString(const std::string& s)
294	3	{
295	3	if (s == "owner") {
296	1	return fs::perms::owner_read \| fs::perms::owner_write;
297	2	} else if (s == "group") {
298	1	return fs::perms::owner_read \| fs::perms::owner_write \|
299	1	fs::perms::group_read;
300	1	} else if (s == "all") {
301	1	return fs::perms::owner_read \| fs::perms::owner_write \|
302	1	fs::perms::group_read \|
303	1	fs::perms::others_read;
304	1	} else {
305	0	return std::nullopt;
306	0	}
307	3	}
308
309		#ifdef __APPLE__
310		FSType GetFilesystemType(const fs::path& path)
311		{
312		if (struct statfs fs_info; statfs(path.c_str(), &fs_info)) {
313		return FSType::ERROR;
314		} else if (std::string_view{fs_info.f_fstypename} == "exfat") {
315		return FSType::EXFAT;
316		}
317		return FSType::OTHER;
318		}
319		#endif