Bitcoin Core 29.99.0
P2P Digital Currency
fs_helpers.cpp
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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#include <fcntl.h>
26#include <sys/resource.h>
27#include <unistd.h>
28#else
29#include <io.h>
30#include <shlobj.h>
31#endif // WIN32
32
33#ifdef __APPLE__
34#include <sys/mount.h>
35#include <sys/param.h>
36#endif
37
45static std::map<std::string, std::unique_ptr<fsbridge::FileLock>> dir_locks GUARDED_BY(cs_dir_locks);
46namespace util {
47LockResult LockDirectory(const fs::path& directory, const fs::path& lockfile_name, bool probe_only)
48{
50 fs::path pathLockFile = directory / lockfile_name;
51
52 // If a lock for this directory already exists in the map, don't try to re-lock it
53 if (dir_locks.count(fs::PathToString(pathLockFile))) {
55 }
56
57 // Create empty lock file if it doesn't exist.
58 if (auto created{fsbridge::fopen(pathLockFile, "a")}) {
59 std::fclose(created);
60 } else {
62 }
63 auto lock = std::make_unique<fsbridge::FileLock>(pathLockFile);
64 if (!lock->TryLock()) {
65 LogError("Error while attempting to lock directory %s: %s\n", fs::PathToString(directory), lock->GetReason());
67 }
68 if (!probe_only) {
69 // Lock successful and we're not just probing, put it into the map
70 dir_locks.emplace(fs::PathToString(pathLockFile), std::move(lock));
71 }
73}
74} // namespace util
75void UnlockDirectory(const fs::path& directory, const fs::path& lockfile_name)
76{
78 dir_locks.erase(fs::PathToString(directory / lockfile_name));
79}
80
82{
84 dir_locks.clear();
85}
86
87bool CheckDiskSpace(const fs::path& dir, uint64_t additional_bytes)
88{
89 constexpr uint64_t min_disk_space = 52428800; // 50 MiB
90
91 uint64_t free_bytes_available = fs::space(dir).available;
92 return free_bytes_available >= min_disk_space + additional_bytes;
93}
94
95std::streampos GetFileSize(const char* path, std::streamsize max)
96{
97 std::ifstream file{path, std::ios::binary};
98 file.ignore(max);
99 return file.gcount();
100}
101
102bool FileCommit(FILE* file)
103{
104 if (fflush(file) != 0) { // harmless if redundantly called
105 LogPrintf("fflush failed: %s\n", SysErrorString(errno));
106 return false;
107 }
108#ifdef WIN32
109 HANDLE hFile = (HANDLE)_get_osfhandle(_fileno(file));
110 if (FlushFileBuffers(hFile) == 0) {
111 LogPrintf("FlushFileBuffers failed: %s\n", Win32ErrorString(GetLastError()));
112 return false;
113 }
114#elif defined(__APPLE__) && defined(F_FULLFSYNC)
115 if (fcntl(fileno(file), F_FULLFSYNC, 0) == -1) { // Manpage says "value other than -1" is returned on success
116 LogPrintf("fcntl F_FULLFSYNC failed: %s\n", SysErrorString(errno));
117 return false;
118 }
119#elif HAVE_FDATASYNC
120 if (fdatasync(fileno(file)) != 0 && errno != EINVAL) { // Ignore EINVAL for filesystems that don't support sync
121 LogPrintf("fdatasync failed: %s\n", SysErrorString(errno));
122 return false;
123 }
124#else
125 if (fsync(fileno(file)) != 0 && errno != EINVAL) {
126 LogPrintf("fsync failed: %s\n", SysErrorString(errno));
127 return false;
128 }
129#endif
130 return true;
131}
132
133void DirectoryCommit(const fs::path& dirname)
134{
135#ifndef WIN32
136 FILE* file = fsbridge::fopen(dirname, "r");
137 if (file) {
138 fsync(fileno(file));
139 fclose(file);
140 }
141#endif
142}
143
144bool TruncateFile(FILE* file, unsigned int length)
145{
146#if defined(WIN32)
147 return _chsize(_fileno(file), length) == 0;
148#else
149 return ftruncate(fileno(file), length) == 0;
150#endif
151}
152
158{
159#if defined(WIN32)
160 return 2048;
161#else
162 struct rlimit limitFD;
163 if (getrlimit(RLIMIT_NOFILE, &limitFD) != -1) {
164 if (limitFD.rlim_cur < (rlim_t)nMinFD) {
165 limitFD.rlim_cur = nMinFD;
166 if (limitFD.rlim_cur > limitFD.rlim_max)
167 limitFD.rlim_cur = limitFD.rlim_max;
168 setrlimit(RLIMIT_NOFILE, &limitFD);
169 getrlimit(RLIMIT_NOFILE, &limitFD);
170 }
171 return limitFD.rlim_cur;
172 }
173 return nMinFD; // getrlimit failed, assume it's fine
174#endif
175}
176
181void AllocateFileRange(FILE* file, unsigned int offset, unsigned int length)
182{
183#if defined(WIN32)
184 // Windows-specific version
185 HANDLE hFile = (HANDLE)_get_osfhandle(_fileno(file));
186 LARGE_INTEGER nFileSize;
187 int64_t nEndPos = (int64_t)offset + length;
188 nFileSize.u.LowPart = nEndPos & 0xFFFFFFFF;
189 nFileSize.u.HighPart = nEndPos >> 32;
190 SetFilePointerEx(hFile, nFileSize, 0, FILE_BEGIN);
191 SetEndOfFile(hFile);
192#elif defined(__APPLE__)
193 // OSX specific version
194 // NOTE: Contrary to other OS versions, the OSX version assumes that
195 // NOTE: offset is the size of the file.
196 fstore_t fst;
197 fst.fst_flags = F_ALLOCATECONTIG;
198 fst.fst_posmode = F_PEOFPOSMODE;
199 fst.fst_offset = 0;
200 fst.fst_length = length; // mac os fst_length takes the # of free bytes to allocate, not desired file size
201 fst.fst_bytesalloc = 0;
202 if (fcntl(fileno(file), F_PREALLOCATE, &fst) == -1) {
203 fst.fst_flags = F_ALLOCATEALL;
204 fcntl(fileno(file), F_PREALLOCATE, &fst);
205 }
206 ftruncate(fileno(file), static_cast<off_t>(offset) + length);
207#else
208#if defined(HAVE_POSIX_FALLOCATE)
209 // Version using posix_fallocate
210 off_t nEndPos = (off_t)offset + length;
211 if (0 == posix_fallocate(fileno(file), 0, nEndPos)) return;
212#endif
213 // Fallback version
214 // TODO: just write one byte per block
215 static const char buf[65536] = {};
216 if (fseek(file, offset, SEEK_SET)) {
217 return;
218 }
219 while (length > 0) {
220 unsigned int now = 65536;
221 if (length < now)
222 now = length;
223 fwrite(buf, 1, now, file); // allowed to fail; this function is advisory anyway
224 length -= now;
225 }
226#endif
227}
228
229#ifdef WIN32
230fs::path GetSpecialFolderPath(int nFolder, bool fCreate)
231{
232 WCHAR pszPath[MAX_PATH] = L"";
233
234 if (SHGetSpecialFolderPathW(nullptr, pszPath, nFolder, fCreate)) {
235 return fs::path(pszPath);
236 }
237
238 LogPrintf("SHGetSpecialFolderPathW() failed, could not obtain requested path.\n");
239 return fs::path("");
240}
241#endif
242
243bool RenameOver(fs::path src, fs::path dest)
244{
245 std::error_code error;
246 fs::rename(src, dest, error);
247 return !error;
248}
249
255bool TryCreateDirectories(const fs::path& p)
256{
257 try {
258 return fs::create_directories(p);
259 } catch (const fs::filesystem_error&) {
260 if (!fs::exists(p) || !fs::is_directory(p))
261 throw;
262 }
263
264 // create_directories didn't create the directory, it had to have existed already
265 return false;
266}
267
268std::string PermsToSymbolicString(fs::perms p)
269{
270 std::string perm_str(9, '-');
271
272 auto set_perm = [&](size_t pos, fs::perms required_perm, char letter) {
273 if ((p & required_perm) != fs::perms::none) {
274 perm_str[pos] = letter;
275 }
276 };
277
278 set_perm(0, fs::perms::owner_read, 'r');
279 set_perm(1, fs::perms::owner_write, 'w');
280 set_perm(2, fs::perms::owner_exec, 'x');
281 set_perm(3, fs::perms::group_read, 'r');
282 set_perm(4, fs::perms::group_write, 'w');
283 set_perm(5, fs::perms::group_exec, 'x');
284 set_perm(6, fs::perms::others_read, 'r');
285 set_perm(7, fs::perms::others_write, 'w');
286 set_perm(8, fs::perms::others_exec, 'x');
287
288 return perm_str;
289}
290
291std::optional<fs::perms> InterpretPermString(const std::string& s)
292{
293 if (s == "owner") {
294 return fs::perms::owner_read | fs::perms::owner_write;
295 } else if (s == "group") {
296 return fs::perms::owner_read | fs::perms::owner_write |
297 fs::perms::group_read;
298 } else if (s == "all") {
299 return fs::perms::owner_read | fs::perms::owner_write |
300 fs::perms::group_read |
301 fs::perms::others_read;
302 } else {
303 return std::nullopt;
304 }
305}
306
307#ifdef __APPLE__
308FSType GetFilesystemType(const fs::path& path)
309{
310 if (struct statfs fs_info; statfs(path.c_str(), &fs_info)) {
311 return FSType::ERROR;
312 } else if (std::string_view{fs_info.f_fstypename} == "exfat") {
313 return FSType::EXFAT;
314 }
315 return FSType::OTHER;
316}
317#endif
Different type to mark Mutex at global scope.
Definition: sync.h:135
#define MAX_PATH
Definition: compat.h:69
static bool create_directories(const std::filesystem::path &p)
Create directory (and if necessary its parents), unless the leaf directory already exists or is a sym...
Definition: fs.h:190
static bool exists(const path &p)
Definition: fs.h:89
static std::string PathToString(const path &path)
Convert path object to a byte string.
Definition: fs.h:151
static GlobalMutex cs_dir_locks
Mutex to protect dir_locks.
Definition: fs_helpers.cpp:39
bool RenameOver(fs::path src, fs::path dest)
Rename src to dest.
Definition: fs_helpers.cpp:243
std::streampos GetFileSize(const char *path, std::streamsize max)
Get the size of a file by scanning it.
Definition: fs_helpers.cpp:95
int RaiseFileDescriptorLimit(int nMinFD)
this function tries to raise the file descriptor limit to the requested number.
Definition: fs_helpers.cpp:157
void DirectoryCommit(const fs::path &dirname)
Sync directory contents.
Definition: fs_helpers.cpp:133
void ReleaseDirectoryLocks()
Release all directory locks.
Definition: fs_helpers.cpp:81
bool TryCreateDirectories(const fs::path &p)
Ignores exceptions thrown by create_directories if the requested directory exists.
Definition: fs_helpers.cpp:255
void AllocateFileRange(FILE *file, unsigned int offset, unsigned int length)
this function tries to make a particular range of a file allocated (corresponding to disk space) it i...
Definition: fs_helpers.cpp:181
bool CheckDiskSpace(const fs::path &dir, uint64_t additional_bytes)
Definition: fs_helpers.cpp:87
std::optional< fs::perms > InterpretPermString(const std::string &s)
Interpret a custom permissions level string as fs::perms.
Definition: fs_helpers.cpp:291
bool TruncateFile(FILE *file, unsigned int length)
Definition: fs_helpers.cpp:144
static std::map< std::string, std::unique_ptr< fsbridge::FileLock > > dir_locks GUARDED_BY(cs_dir_locks)
A map that contains all the currently held directory locks.
std::string PermsToSymbolicString(fs::perms p)
Convert fs::perms to symbolic string of the form 'rwxrwxrwx'.
Definition: fs_helpers.cpp:268
bool FileCommit(FILE *file)
Ensure file contents are fully committed to disk, using a platform-specific feature analogous to fsyn...
Definition: fs_helpers.cpp:102
void UnlockDirectory(const fs::path &directory, const fs::path &lockfile_name)
Definition: fs_helpers.cpp:75
#define LogError(...)
Definition: logging.h:358
#define LogPrintf(...)
Definition: logging.h:361
FILE * fopen(const fs::path &p, const char *mode)
Definition: fs.cpp:26
LockResult
Definition: fs_helpers.h:57
LockResult LockDirectory(const fs::path &directory, const fs::path &lockfile_name, bool probe_only)
Definition: fs_helpers.cpp:47
#define LOCK(cs)
Definition: sync.h:259
std::string SysErrorString(int err)
Return system error string from errno value.
Definition: syserror.cpp:19