syscalls: implement getcwd syscall

include/exec_from_file.h

@@ -9,4 +9,4 @@
 #define USER_STACK_SIZE         0x4000         // 16KB stack (4 pages)
 #define USER_STACK_BOTTOM     (USER_STACK_TOP - USER_STACK_SIZE)
 
-void exec_from_file(l9660_file* fs_file, const char* dirname);
+void exec_from_file(l9660_file* fs_file, l9660_dir* dir);

include/string.h

@@ -10,5 +10,6 @@ void* memset(void*, int, size_t);
 size_t strlen(const char*);
 char *strcat(char *dest, const char *src);
 char *strcpy(char *dest, const char *src);
+char *strtok(char *str, const char *delim);
 
 #endif

include/vfs.h

@@ -22,4 +22,7 @@ void test_iso9660();
 int vfs_read_file_by_path(const char* path, uint8_t** buffer);
 void follow_path(const char* path, l9660_file* file, l9660_dir* dir);
 
+l9660_status find_name_for_sector(char* name_buf, int buf_len, l9660_dir* parent_dir, uint32_t child_sector);
+bool is_root_dir(l9660_dir* dir);
+
 #endif