diff -r ef9237601f24 -r 6a6462ce8a08 librazor/razor.c
--- a/librazor/razor.c	Thu Oct 01 19:54:03 2009 +0100
+++ b/librazor/razor.c	Thu Oct 01 20:02:12 2009 +0100
@@ -37,6 +37,9 @@
 #include <fnmatch.h>
 #include <limits.h>
 #include <assert.h>
+#ifdef MSWIN_API
+#include <windows.h>
+#endif
 
 #include "razor-internal.h"
 #include "razor.h"
@@ -93,6 +96,8 @@
 	empty = array_add(&set->string_pool, 1);
 	*empty = '\0';
 
+	set->lock_fd = -1;
+
 	return set;
 }
 
@@ -138,6 +143,13 @@
 		return -1;
 	}
 
+	if (set->mapped_files == NULL) {
+		for (i = 0; i < ARRAY_SIZE(razor_sections); i++) {
+			array = (void *) set + razor_sections[i].offset;
+			array_release(array);
+		}
+	}
+
 	file->next = set->mapped_files;
 	set->mapped_files = file;
 
@@ -167,6 +179,7 @@
 	struct razor_set *set;
 
 	set = zalloc(sizeof *set);
+	set->lock_fd = -1;
 	if (razor_set_bind_sections(set, filename)){
 		free(set);
 		return NULL;
@@ -174,6 +187,56 @@
 	return set;
 }
 
+int
+razor_set_aquire_lock(struct razor_set *set, const char *path, int exclusive)
+{
+	int fd;
+	assert(set != NULL);
+
+	if (path) {
+		fd = open(path, O_CREAT | O_RDWR | O_TRUNC | O_BINARY, 0666);
+		if (fd < 0)
+			return -1;
+	} else {
+		fd = -1;
+	}
+
+#ifdef MSWIN_API
+	DWORD flags = LOCKFILE_FAIL_IMMEDIATELY;
+	OVERLAPPED lock = {0};
+
+	if (exclusive)
+		flags |= LOCKFILE_EXCLUSIVE_LOCK;
+	if (fd >= 0 && !LockFileEx(_get_osfhandle(fd), flags, 0, 1, 0, &lock)) {
+		close(fd);
+		return -1;
+	}
+	if (set->lock_fd >= 0)
+		(void)UnlockFile(_get_osfhandle(set->lock_fd), 0, 0, 1, 0);
+#else
+	struct flock lock = {0};
+
+	lock.l_type = exclusive ? F_WRLCK : F_RDLCK;
+	lock.l_whence = SEEK_SET;
+	lock.l_start = 0;
+	lock.l_len = 0;
+	if (fd >= 0 && fcntl(fd, F_SETLK, &lock) < 0) {
+		close(fd);
+		return -1;
+	}
+	if (set->lock_fd >= 0) {
+		lock.l_type = F_UNLCK;
+		(void)fcntl(set->lock_fd, F_SETLK, &lock);
+	}
+#endif
+
+	if (set->lock_fd >= 0)
+		close(set->lock_fd);
+	set->lock_fd = fd;
+
+	return 0;
+}
+
 RAZOR_EXPORT void
 razor_set_destroy(struct razor_set *set)
 {
@@ -196,6 +259,7 @@
 		}
 	}
 
+	razor_set_aquire_lock(set, NULL, 0);
 	free(set);
 }