Merge branch 'Alex/19-implement-remove-system-call' into 'feature/system-calls'

Implementing the remove syscall

See merge request !17

Makefile.build

@@ -68,6 +68,7 @@ userprog_SRC += userprog/syscall_open.c
 userprog_SRC += userprog/syscall_halt.c
 userprog_SRC += userprog/syscall_wait.c
 userprog_SRC += userprog/syscall_create.c
+userprog_SRC += userprog/syscall_remove.c
 userprog_SRC += userprog/syscall_write.c
 userprog_SRC += userprog/file_descriptors_map.c
 

userprog/syscall.c

@@ -69,7 +69,10 @@ syscall_handler (struct intr_frame *f UNUSED)
     break;
   case SYSCALL_CREATE:
     syscall_create(f);
-    break;
+	break;
+  case SYSCALL_REMOVE:
+	syscall_remove(f);
+	break;
   case SYSCALL_WRITE:
     syscall_write(f);
     break;

userprog/syscall_remove.c

+/*
+ * Deletes the file called file. Returns true if successful, false otherwise. 
+ * A file may be removed regardless of whether it is open or closed, and 
+ * Removing an open file does not close it. See Removing an Open File, for
+ * Details.
+ *
+ * Authored by Alex Stratford
+ */
+
+
+#include "system_calls.h"
+#include "threads/interrupt.h" // Dependency for intr_frame struct
+#include "filesys/file.h" // Dependency for and file struct
+#include "filesys/filesys.h" // Dependency for filesys_remove
+
+void syscall_remove(struct intr_frame *f) {
+	// pop off first int argument from interrupt frame
+	char* file_name = (void*)*((int*)f->esp + 1);
+	// Described in filesys.h, opens the file
+	if (filesys_remove(file_name) == false) { // Checking if file is empty or non-existent
+		f->eax = false; // Returning a failure state
+		return;
+	}
+	f->eax = true;
+}

userprog/system_calls.h

@@ -49,6 +49,14 @@ void syscall_write(struct intr_frame *f);
  */
 void syscall_open(struct intr_frame *f);
 
+/*
+ * Deletes the file called file. Returns true if successful, false otherwise.
+ * A file may be removed regardless of whether it is open or closed, and
+ * Removing an open file does not close it. See Removing an Open File, for
+ * Details.
+ */
+void syscall_remove(struct intr_frame *f);
+
 /*
  * special additional stuff for handling file descriptors because they're annoying
  */