1 files changed, 82 insertions, 0 deletions
diff --git a/maildrop/filelock.C b/maildrop/filelock.C
new file mode 100644
index 0000000..535ee3b
--- /dev/null
+++ b/maildrop/filelock.C
@@ -0,0 +1,82 @@
+#include	"filelock.h"
+#include	"mio.h"
+#if HAVE_FCNTL_H
+#include	<fcntl.h>
+#endif
+#if HAVE_SYS_STAT_H
+#include        <sys/stat.h>
+#endif
+#if HAVE_UNISTD_H
+#include	<unistd.h>
+#endif
+#if HAVE_SYS_FILE_H
+#include	<sys/file.h>
+#endif
+#include	<errno.h>
+
+#include	"liblock/config.h"
+#include	"liblock/liblock.h"
+
+
+void FileLock::cleanup()
+{
+	UnLock();
+}
+
+void FileLock::forked()
+{
+	UnLock();
+}
+
+FileLock::FileLock() : fd(-1)
+{
+}
+
+FileLock::~FileLock()
+{
+	UnLock();
+}
+
+void FileLock::Lock(const char *filename)
+{
+	UnLock();
+
+	if ((fd=mopen(filename, O_CREAT | O_WRONLY, 0600)) < 0)
+		throw "Unable to create flock file.";
+
+	do_filelock(fd);
+}
+
+
+void FileLock::do_filelock(int fd)
+{
+int	flockrc;
+
+	while ((flockrc=ll_lock_ex(fd)) < 0 && errno == EINTR)
+		;
+
+	if (flockrc < 0)
+	{
+	struct stat stat_buf;
+
+		// FreeBSD has problems locking /dev/null.  Presume that if
+		// you're writing to a device file, you know what you're doing.
+
+		if (fstat(fd, &stat_buf) >= 0 && (
+			S_ISREG(stat_buf.st_mode) || S_ISDIR(stat_buf.st_mode)))
+		{
+			return;
+		}
+
+		throw "flock() failed.";
+	}
+}
+
+void FileLock::UnLock()
+{
+	if (fd >= 0)
+	{
+		mclose(fd);
+		fd= -1;
+	}
+}