started execv, not sure how caret.proj will do stuff, guess i'll find out when i repoen it.

caret.proj

@@ -0,0 +1,8 @@
+{
+  "folders": [
+    {
+      "retained": "0B70008126CD936C26D1187C2B0AEEB7:os161-1.99",
+      "path": "/os161-1.99"
+    }
+  ]
+}

kern/syscall/proc_syscalls.c

@@ -136,3 +136,110 @@ int sys_fork(struct trapframe * tf, int * retval)
   else *retval = child->pid;
   return 0;
 }
+
+// args is an array of null terminated strings, with the last element being a null pointer so we don't overflow if iterating
+// since this is a userptr type, we need to use copyin and copyout to get data properly
+// hopefully the path in program is actually a full filepath
+int execv(const char * program, userptr_t args)
+{
+  userptr_t ** temp = args;
+  int argcount = 0;
+  char ** argv;
+  
+  // see how long args is
+  while (1)
+  {
+    char * temp2;
+    if (copyin(temp, temp2, sizeof(char *))) return errno;
+    if (!(temp2)) break;
+    temp += sizeof(char *);
+    ++argcount;
+  }
+  
+  // allocate space for argv
+  argv = kmalloc(argcount * sizeof(char *));
+  if (!argv) return ENOMEM;
+  
+  // get kernel copy of args in argv
+  temp = args;
+  for (int i = 0; i < argcount; ++i)
+  {
+    if (copyin(args, argv[i], sizeof(char *)))
+    {
+      kfree(argv);
+      return errno;
+    }
+    
+    temp += sizeof(char *);
+  }
+  
+  // allocate space for filepath
+  const char * filepath = kmalloc(sizeof(program));
+  if (!(filepath))
+  {
+    kfree(argv);
+    return ENOMEM;
+  }
+  
+  // get kernel copy of filepath
+  size_t useless;
+  if (copyinstr((const_userptr_t)program, filepath, strlen(program) + 1, &useless))
+  {
+    kfree(argv);
+    kfree(filepath);
+    return errno;
+  }
+  
+  // open program file
+  struct vnode * v;
+  if (vfs_open(filepath, O_RDONLY, 0, &v))
+  {
+    kfree(argv);
+    kfree(filepath);
+    return errno;
+  }
+  
+  // create new address space
+	struct addrspace * as = as_create();
+	if (!(as))
+	{
+		vfs_close(v);
+		kfree(argv);
+		kfree(filepath);
+		return ENOMEM;
+	}
+
+	// Switch to the new as and activate. keep old in case we fail later
+	struct addrspace * oldas = curproc_getas();
+	curproc_setas(as);
+	as_activate();
+
+	// Load santa's favourite slave
+	if (load_elf(v, &entrypoint))
+	{
+		vfs_close(v);
+		kfree(argv);
+		kfree(filepath);
+		curproc_setas(oldas);
+		as_destroy(as);
+		return errno;
+	}
+
+	// close the file now that we're done
+	vfs_close(v);
+  
+  // create the new stack
+  vaddr_t newstack;
+  if (as_define_stack(as, &newstack))
+  {
+    kfree(argv);
+    kfree(filepath);
+    curproc_setas(oldas);
+    as_destroy(as);
+    return errno;
+  }
+  
+  userptr_t userArgv;
+  
+  // need to copy data over into the new address space, as rn it is all in kernel heap
+}