1 files changed, 58 insertions, 0 deletions
diff --git a/kern/loader.c b/kern/loader.c
new file mode 100644
index 0000000..2dfd8e3
--- /dev/null
+++ b/kern/loader.c
@@ -0,0 +1,58 @@
+/**
+ * The 15-410 kernel project.
+ * @name loader.c
+ *
+ * Functions for the loading
+ * of user programs from binary
+ * files should be written in
+ * this file. The function
+ * elf_load_helper() is provided
+ * for your use.
+ */
+
+/* --- Includes --- */
+#include <elf_410.h>
+#include <exec2obj.h>
+#include <loader.h>
+#include <malloc.h>
+#include <stdio.h>
+#include <string.h>
+
+/* --- Local function prototypes --- */
+
+/**
+ * Copies data from a file into a buffer.
+ *
+ * @param filename   the name of the file to copy data from
+ * @param offset     the location in the file to begin copying from
+ * @param size       the number of bytes to be copied
+ * @param buf        the buffer to copy the data into
+ *
+ * @return returns the number of bytes copied on succes; -1 on failure
+ */
+int getbytes(const char* filename, int offset, int size, char* buf) {
+    file_t* f = find_file(filename);
+    if (f == NULL || offset > f->execlen) {
+        return -1;
+    }
+    return read_file(f, offset, size, buf);
+}
+
+int read_file(file_t* f, int offset, int size, char* buf) {
+    int src_size = size;
+    if (f->execlen - offset < size) {
+        src_size = f->execlen - offset;
+    }
+    memcpy(buf, f->execbytes + offset, src_size);
+    return src_size;
+}
+
+file_t* find_file(const char* name) {
+    int i;
+    for (i = 0; i < exec2obj_userapp_count; i++) {
+        if (strcmp(name, exec2obj_userapp_TOC[i].execname) == 0) {
+            return &exec2obj_userapp_TOC[i];
+        }
+    }
+    return NULL;
+}