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https://github.com/privatevoid-net/nix-super.git
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* Remove most Cygwin-specific code. Cygwin 1.7 implements advisory
POSIX locks, and simulates Unix-style file deletion semantics sufficiently. Note that this means that Nix won't work on Cygwin 1.5 anymore.
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4 changed files with 5 additions and 112 deletions
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@ -15,11 +15,6 @@
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#include <fcntl.h>
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#include <unistd.h>
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#ifdef __CYGWIN__
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#include <windows.h>
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#include <sys/cygwin.h>
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#endif
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namespace nix {
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@ -179,15 +174,6 @@ void LocalStore::addTempRoot(const Path & path)
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fdGCLock.close();
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/* Note that on Cygwin a lot of the following complexity
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is unnecessary, since we cannot delete open lock
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files. If we have the lock file open, then it's valid;
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if we can delete it, then it wasn't in use any more.
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Also note that on Cygwin we cannot "upgrade" a lock
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from a read lock to a write lock. */
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#ifndef __CYGWIN__
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debug(format("acquiring read lock on `%1%'") % fnTempRoots);
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lockFile(fdTempRoots, ltRead, true);
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@ -201,10 +187,6 @@ void LocalStore::addTempRoot(const Path & path)
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/* The garbage collector deleted this file before we could
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get a lock. (It won't delete the file after we get a
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lock.) Try again. */
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#else
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break;
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#endif
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}
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}
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@ -217,14 +199,9 @@ void LocalStore::addTempRoot(const Path & path)
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string s = path + '\0';
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writeFull(fdTempRoots, (const unsigned char *) s.c_str(), s.size());
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#ifndef __CYGWIN__
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/* Downgrade to a read lock. */
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debug(format("downgrading to read lock on `%1%'") % fnTempRoots);
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lockFile(fdTempRoots, ltRead, true);
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#else
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debug(format("releasing write lock on `%1%'") % fnTempRoots);
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lockFile(fdTempRoots, ltNone, true);
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#endif
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}
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@ -252,19 +229,6 @@ static void readTempRoots(PathSet & tempRoots, FDs & fds)
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Path path = (format("%1%/%2%/%3%") % nixStateDir % tempRootsDir % *i).str();
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debug(format("reading temporary root file `%1%'") % path);
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#ifdef __CYGWIN__
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/* On Cygwin we just try to delete the lock file. */
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char win32Path[MAX_PATH];
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cygwin_conv_to_full_win32_path(path.c_str(), win32Path);
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if (DeleteFile(win32Path)) {
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printMsg(lvlError, format("removed stale temporary roots file `%1%'")
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% path);
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continue;
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} else
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debug(format("delete of `%1%' failed: %2%") % path % GetLastError());
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#endif
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FDPtr fd(new AutoCloseFD(open(path.c_str(), O_RDWR, 0666)));
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if (*fd == -1) {
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/* It's okay if the file has disappeared. */
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@ -276,7 +240,6 @@ static void readTempRoots(PathSet & tempRoots, FDs & fds)
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//FDPtr fd(new AutoCloseFD(openLockFile(path, false)));
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//if (*fd == -1) continue;
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#ifndef __CYGWIN__
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/* Try to acquire a write lock without blocking. This can
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only succeed if the owning process has died. In that case
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we don't care about its temporary roots. */
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@ -287,7 +250,6 @@ static void readTempRoots(PathSet & tempRoots, FDs & fds)
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writeFull(*fd, (const unsigned char *) "d", 1);
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continue;
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}
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#endif
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/* Acquire a read lock. This will prevent the owning process
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from upgrading to a write lock, therefore it will block in
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@ -8,11 +8,6 @@
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#include <sys/stat.h>
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#include <fcntl.h>
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#ifdef __CYGWIN__
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#include <windows.h>
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#include <sys/cygwin.h>
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#endif
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namespace nix {
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@ -21,72 +16,24 @@ int openLockFile(const Path & path, bool create)
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{
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AutoCloseFD fd;
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#ifdef __CYGWIN__
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/* On Cygwin we have to open the lock file without "DELETE"
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sharing mode; otherwise Windows will allow open lock files to
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be deleted (which is almost but not quite what Unix does). */
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char win32Path[MAX_PATH + 1];
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cygwin_conv_to_full_win32_path(path.c_str(), win32Path);
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SECURITY_ATTRIBUTES sa; /* required, otherwise inexplicably bad shit happens */
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sa.nLength = sizeof sa;
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sa.lpSecurityDescriptor = 0;
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sa.bInheritHandle = TRUE;
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HANDLE h = CreateFile(win32Path, GENERIC_READ | GENERIC_WRITE,
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FILE_SHARE_READ | FILE_SHARE_WRITE, &sa,
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(create ? OPEN_ALWAYS : OPEN_EXISTING),
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FILE_ATTRIBUTE_NORMAL, 0);
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if (h == INVALID_HANDLE_VALUE) {
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if (create || GetLastError() != ERROR_FILE_NOT_FOUND)
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throw Error(format("opening lock file `%1%'") % path);
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fd = -1;
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}
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else
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fd = cygwin_attach_handle_to_fd((char *) path.c_str(), -1, h, 1, O_RDWR);
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#else
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fd = open(path.c_str(), O_RDWR | (create ? O_CREAT : 0), 0666);
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if (fd == -1 && (create || errno != ENOENT))
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throw SysError(format("opening lock file `%1%'") % path);
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#endif
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return fd.borrow();
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}
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void deleteLockFilePreClose(const Path & path, int fd)
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void deleteLockFile(const Path & path, int fd)
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{
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#ifndef __CYGWIN__
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/* Get rid of the lock file. Have to be careful not to introduce
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races. */
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/* On Unix, write a (meaningless) token to the file to indicate to
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races. Write a (meaningless) token to the file to indicate to
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other processes waiting on this lock that the lock is stale
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(deleted). */
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unlink(path.c_str());
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writeFull(fd, (const unsigned char *) "d", 1);
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/* Note that the result of unlink() is ignored; removing the lock
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file is an optimisation, not a necessity. */
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#endif
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}
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void deleteLockFilePostClose(const Path & path)
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{
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#ifdef __CYGWIN__
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/* On Windows, just try to delete the lock file. This will fail
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if anybody still has the file open. We cannot use unlink()
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here, because Cygwin emulates Unix semantics of allowing an
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open file to be deleted (but fakes it - the file isn't actually
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deleted until later, so a file with the same name cannot be
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created in the meantime). */
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char win32Path[MAX_PATH + 1];
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cygwin_conv_to_full_win32_path(path.c_str(), win32Path);
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if (DeleteFile(win32Path))
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debug(format("delete of `%1%' succeeded") % path.c_str());
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else
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/* Not an error: probably means that the lock is still opened
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by someone else. */
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debug(format("delete of `%1%' failed: %2%") % path.c_str() % GetLastError());
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#endif
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}
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@ -220,15 +167,13 @@ PathLocks::~PathLocks()
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void PathLocks::unlock()
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{
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foreach (list<FDPair>::iterator, i, fds) {
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if (deletePaths) deleteLockFilePreClose(i->second, i->first);
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if (deletePaths) deleteLockFile(i->second, i->first);
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lockedPaths.erase(i->second);
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if (close(i->first) == -1)
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printMsg(lvlError,
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format("error (ignored): cannot close lock file on `%1%'") % i->second);
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if (deletePaths) deleteLockFilePostClose(i->second);
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debug(format("lock released on `%1%'") % i->second);
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}
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@ -12,10 +12,8 @@ namespace nix {
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because it doesn't exist. Any other error throws an exception. */
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int openLockFile(const Path & path, bool create);
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/* Delete an open lock file. Both must be called to be fully portable
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between Unix and Windows. */
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void deleteLockFilePreClose(const Path & path, int fd);
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void deleteLockFilePostClose(const Path & path);
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/* Delete an open lock file. */
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void deleteLockFile(const Path & path, int fd);
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enum LockType { ltRead, ltWrite, ltNone };
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@ -1,9 +1,5 @@
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#include "config.h"
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#ifdef __CYGWIN__
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#include <windows.h>
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#endif
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#include <iostream>
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#include <cerrno>
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#include <cstdio>
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void quickExit(int status)
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{
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#ifdef __CYGWIN__
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/* Hack for Cygwin: _exit() doesn't seem to work quite right,
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since some Berkeley DB code appears to be called when a child
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exits through _exit() (e.g., because execve() failed). So call
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the Windows API directly. */
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ExitProcess(status);
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#else
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_exit(status);
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#endif
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}
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