diff options
Diffstat (limited to 'third_party/nix/src/libstore/pathlocks.cc')
| -rw-r--r-- | third_party/nix/src/libstore/pathlocks.cc | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/third_party/nix/src/libstore/pathlocks.cc b/third_party/nix/src/libstore/pathlocks.cc index ffec3d7d7e..a0d7b721ec 100644 --- a/third_party/nix/src/libstore/pathlocks.cc +++ b/third_party/nix/src/libstore/pathlocks.cc @@ -18,8 +18,9 @@ AutoCloseFD openLockFile(const Path& path, bool create) { AutoCloseFD fd; fd = open(path.c_str(), O_CLOEXEC | O_RDWR | (create ? O_CREAT : 0), 0600); - if (!fd && (create || errno != ENOENT)) + if (!fd && (create || errno != ENOENT)) { throw SysError(format("opening lock file '%1%'") % path); + } return fd; } @@ -37,22 +38,24 @@ void deleteLockFile(const Path& path, int fd) { bool lockFile(int fd, LockType lockType, bool wait) { int type; - if (lockType == ltRead) + if (lockType == ltRead) { type = LOCK_SH; - else if (lockType == ltWrite) + } else if (lockType == ltWrite) { type = LOCK_EX; - else if (lockType == ltNone) + } else if (lockType == ltNone) { type = LOCK_UN; - else + } else { abort(); + } if (wait) { while (flock(fd, type) != 0) { checkInterrupt(); - if (errno != EINTR) + if (errno != EINTR) { throw SysError(format("acquiring/releasing lock")); - else + } else { return false; + } } } else { while (flock(fd, type | LOCK_NB) != 0) { @@ -118,16 +121,18 @@ bool PathLocks::lockPaths(const PathSet& paths, const string& waitMsg, /* Check that the lock file hasn't become stale (i.e., hasn't been unlinked). */ struct stat st; - if (fstat(fd.get(), &st) == -1) + if (fstat(fd.get(), &st) == -1) { throw SysError(format("statting lock file '%1%'") % lockPath); - if (st.st_size != 0) + } + if (st.st_size != 0) { /* This lock file has been unlinked, so we're holding a lock on a deleted file. This means that other processes may create and acquire a lock on `lockPath', and proceed. So we must retry. */ DLOG(INFO) << "open lock file '" << lockPath << "' has become stale"; - else + } else { break; + } } /* Use borrow so that the descriptor isn't closed. */ |