1 files changed, 15 insertions, 0 deletions
diff --git a/src/user/knob/file.c b/src/user/knob/file.c
index 3083503..283f984 100644
--- a/src/user/knob/file.c
+++ b/src/user/knob/file.c
@@ -1,4 +1,5 @@
 #include <knob/format.h>
+#include <knob/block.h>
 #include <knob/panic.h>
 #include <knob/heap.h>
 
@@ -83,6 +84,16 @@ uint32_t read_from_file(struct file *f, uint32_t max, void *buf) {
   return read;
 }
 
+uint32_t write_to_file(struct file *f, uint32_t max, void *buf) {
+  if (f->position + max > f->length)
+    _set_file_size(f->handle, f->length = f->position + max);
+
+  uint32_t written = _file_write(f->handle, f->position, max, buf);
+
+  f->position += written;
+  return written;
+}
+
 //return value and max_length don't include null terminator
 uint32_t read_line_from_file(struct file *f, char *sz, uint32_t max_length) {
   uint8_t i;
@@ -114,6 +125,10 @@ uint32_t file_size(struct file *f) {
   return f->length;
 }
 
+void trunc_file(struct file *f) {
+  _set_file_size(f->handle, f->length = f->position);
+}
+
 //return value must be manually freed, unless it is a null pointer
 _dir_info_entry_t *get_directory_info(const char *path, uint32_t *count_out) {
   uint8_t dn;