From b35735d8b28af206fa0b293c796bf44c62dde678 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Mon, 19 Jun 2006 14:43:13 +0000 Subject: [PATCH] * On Windows we cannot delete open (lock) files, so we delete lock files after we've closed them. Since this only succeeds if the lock is no longer opened by any process, the token trick used on Unix is not necessary. --- src/libstore/pathlocks.cc | 51 ++++++++++++++++++++++++++++++++++++--- 1 file changed, 47 insertions(+), 4 deletions(-) diff --git a/src/libstore/pathlocks.cc b/src/libstore/pathlocks.cc index 7f7cbdf15..bb1644a9a 100644 --- a/src/libstore/pathlocks.cc +++ b/src/libstore/pathlocks.cc @@ -6,6 +6,11 @@ #include "pathlocks.hh" +#ifdef __CYGWIN__ +#include +#include +#endif + bool lockFile(int fd, LockType lockType, bool wait) { @@ -87,11 +92,28 @@ void PathLocks::lockPaths(const PathSet & _paths, const string & waitMsg) AutoCloseFD fd; while (1) { - + /* Open/create the lock file. */ +#ifdef __CYGWIN__ + char win32Path[MAX_PATH]; + cygwin_conv_to_full_win32_path(lockPath.c_str(), win32Path); + + SECURITY_ATTRIBUTES sa; + sa.nLength = sizeof sa; + sa.lpSecurityDescriptor = 0; + sa.bInheritHandle = TRUE; + HANDLE h = CreateFile(win32Path, GENERIC_READ, + FILE_SHARE_READ | FILE_SHARE_WRITE, &sa, OPEN_ALWAYS, + FILE_ATTRIBUTE_NORMAL, 0); + if (h == INVALID_HANDLE_VALUE) + throw Error(format("opening lock file `%1%'") % lockPath); + + fd = cygwin_attach_handle_to_fd((char *) lockPath.c_str(), -1, h, 1, O_RDWR); +#else fd = open(lockPath.c_str(), O_WRONLY | O_CREAT, 0666); if (fd == -1) throw SysError(format("opening lock file `%1%'") % lockPath); +#endif /* Acquire an exclusive lock. */ if (!lockFile(fd, ltWrite, false)) { @@ -126,19 +148,40 @@ void PathLocks::lockPaths(const PathSet & _paths, const string & waitMsg) PathLocks::~PathLocks() { for (list::iterator i = fds.begin(); i != fds.end(); i++) { +#ifndef __CYGWIN__ if (deletePaths) { - /* Write a (meaningless) token to the file to indicate to - other processes waiting on this lock that the lock is - stale (deleted). */ + /* Get rid of the lock file. Have to be careful not to + introduce races. */ + /* On Unix, write a (meaningless) token to the file to + indicate to other processes waiting on this lock that + the lock is stale (deleted). */ unlink(i->second.c_str()); writeFull(i->first, (const unsigned char *) "d", 1); /* Note that the result of unlink() is ignored; removing the lock file is an optimisation, not a necessity. */ } +#endif lockedPaths.erase(i->second); if (close(i->first) == -1) printMsg(lvlError, format("error (ignored): cannot close lock file on `%1%'") % i->second); +#ifdef __CYGWIN__ + if (deletePaths) { + /* On Windows, just try to delete the lock file. This + will fail if anybody still has the file open. We + cannot use unlink() here, because Cygwin emulates Unix + semantics of allowing an open file to be deleted (but + fakes it - the file isn't actually deleted until later, + so a file with the same name cannot be created in the + meantime). */ + char win32Path[MAX_PATH]; + cygwin_conv_to_full_win32_path(i->second.c_str(), win32Path); + if (DeleteFile(win32Path)) + debug(format("delete of `%1%' succeeded") % i->second.c_str()); + else + debug(format("delete of `%1%' failed: %2%") % i->second.c_str() % GetLastError()); + } +#endif debug(format("lock released on `%1%'") % i->second); } }