apps: add a new example app which does all kinds of stdio misbehaving >.<

apps/Makefile

@@ -1,4 +1,4 @@
-APPS := init fib leap art memeater
+APPS := init fib leap art memeater quota
 
 APPS_DIR := $(LUNA_ROOT)/apps
 APPS_SRC := $(APPS_DIR)/src

apps/src/quota.c

@@ -0,0 +1,22 @@
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+
+int main()
+{
+    if (open("/file/that/does/not/exist", O_RDONLY) < 0) { perror("open"); }
+    int sys = open("/sys", O_RDONLY);
+    if (sys < 0) { perror("open"); }
+    if (read(sys, NULL, 20) < 0) { perror("read"); }
+    char buf[20];
+    if (read(sys, buf, 20) < 0) { perror("read"); }
+    if (close(sys) < 0) { perror("close"); }
+    for (int i = 0; i < 10; i++)
+    {
+        if (open("/", O_RDONLY) < 0) { perror("open"); }
+    }
+    int exec;
+    if ((exec = open("/bin/quota", O_RDONLY)) < 0) { perror("open"); }
+    if (read(exec, buf, 20) < 0) { perror("read"); }
+    if (close(exec) < 0) { perror("close"); }
+}

kernel/src/main.cpp

@@ -33,8 +33,6 @@
 #include "thread/PIT.h"
 #include "thread/Scheduler.h"
 
-extern "C" void _userspace();
-
 extern "C" void _start()
 {
     Init::check_magic();
@@ -125,7 +123,7 @@ extern "C" void _start()
         }
     });
 
-    uint64_t demo = Mersenne::get() % 5;
+    uint64_t demo = Mersenne::get() % 6;
 
     switch (demo)
     {
@@ -149,6 +147,10 @@ extern "C" void _start()
         kinfoln("Loading demo: memory eating program");
         Scheduler::load_user_task("bin/memeater");
         break;
+    case 5:
+        kinfoln("Loading demo: misbehaving program");
+        Scheduler::load_user_task("bin/quota");
+        break;
     default: break;
     }