3 files changed, 29 insertions, 6 deletions

diff --git a/c_src/filebuffer.c b/c_src/filebuffer.c
index 8285695..87b9859 100644
--- a/c_src/filebuffer.c
+++ b/c_src/filebuffer.c
@@ -177,7 +177,7 @@ bf_read(buffered_file *file, uint64_t offset, size_t length, char **error)
 }
 
 buffered_file *
-bf_open(const char *path, int flags, const char *name)
+bf_open(const char *path, int flags, const char *name, int lock)
 {
         buffered_file *file = malloc(sizeof(buffered_file));
 
@@ -187,6 +187,16 @@ bf_open(const char *path, int flags, const char *name)
                 return NULL;
         }
 
+        if (lock) {
+                int ret;
+
+                ret = flock(file->fd, LOCK_EX|LOCK_NB);
+                if (ret == -1) {
+                        warn("flock %s", path);
+                        return NULL;
+                }
+        }
+
         file->name = name;
 
         off_t datafile_filesize = lseek(file->fd, 0, SEEK_END);
diff --git a/c_src/filebuffer.h b/c_src/filebuffer.h
index 05c656e..f24d86a 100644
--- a/c_src/filebuffer.h
+++ b/c_src/filebuffer.h
@@ -9,7 +9,7 @@
 typedef struct buffered_file buffered_file;
 
 buffered_file *
-bf_open(const char *path, int flags, const char *name);
+bf_open(const char *path, int flags, const char *name, int lock);
 void
 bf_close(buffered_file *file);
 void
diff --git a/c_src/permdb.c b/c_src/permdb.c
index 1163dc7..09e1fd7 100644
--- a/c_src/permdb.c
+++ b/c_src/permdb.c
@@ -432,14 +432,27 @@ permdb_alloc(const char *dbpath)
         }
 
         permdb_object *state = malloc(sizeof(permdb_object));
-        state->datafile = bf_open(dbpath, O_RDWR|O_CREAT, "datafile");
-        state->indexfile = bf_open(idxpath, O_RDWR|O_CREAT, "indexfile");
-
-        free(idxpath);
 
         state->nodecache = NULL;
         state->dirtynodes = NULL;
         state->error = NULL;
+
+        state->datafile = bf_open(dbpath, O_RDWR|O_CREAT, "datafile", 1);
+        if (state->datafile == NULL) {
+                permdb_free(state);
+                free(idxpath);
+                return NULL;
+        }
+
+        state->indexfile = bf_open(idxpath, O_RDWR|O_CREAT, "indexfile", 1);
+        if (state->indexfile == NULL) {
+                permdb_free(state);
+                free(idxpath);
+                return NULL;
+        }
+
+        free(idxpath);
+
         if (bf_total_length(state->datafile) == 0
             && bf_total_length(state->indexfile) == 0) {
                 dprintf(WRITE, (stderr, "writing header\n"));