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Fix locking on WSL using flock instead of fcntl #2314

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Merged
merged 1 commit into from
Sep 1, 2021
Merged

Fix locking on WSL using flock instead of fcntl #2314

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37 changes: 29 additions & 8 deletions src/fs.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,9 @@

#ifndef WIN32
#include <fcntl.h>
#include <string>
#include <sys/file.h>
#include <sys/utsname.h>
#else
#ifndef NOMINMAX
#define NOMINMAX
Expand Down Expand Up @@ -49,20 +52,38 @@ FileLock::~FileLock()
}
}

static bool IsWSL()
{
struct utsname uname_data;
return uname(&uname_data) == 0 && std::string(uname_data.version).find("Microsoft") != std::string::npos;
}

bool FileLock::TryLock()
{
if (fd == -1) {
return false;
}
struct flock lock;
lock.l_type = F_WRLCK;
lock.l_whence = SEEK_SET;
lock.l_start = 0;
lock.l_len = 0;
if (fcntl(fd, F_SETLK, &lock) == -1) {
reason = GetErrorReason();
return false;

// Exclusive file locking is broken on WSL using fcntl (issue #18622)
// This workaround can be removed once the bug on WSL is fixed
static const bool is_wsl = IsWSL();
if (is_wsl) {
if (flock(fd, LOCK_EX | LOCK_NB) == -1) {
reason = GetErrorReason();
return false;
}
} else {
struct flock lock;
lock.l_type = F_WRLCK;
lock.l_whence = SEEK_SET;
lock.l_start = 0;
lock.l_len = 0;
if (fcntl(fd, F_SETLK, &lock) == -1) {
reason = GetErrorReason();
return false;
}
}

return true;
}
#else
Expand Down