a little bit of hooking, io redirect and cleanup

Author: hitodama

kern/file_hello_world/source/main.c

@@ -1,23 +1,8 @@
-#define _XOPEN_SOURCE 700
-#define __BSD_VISIBLE 1
-#define _KERNEL
-#define _STANDALONE
-#define _WANT_UCRED
-#include <sys/cdefs.h>
-#include <sys/types.h>
-#include <sys/limits.h>
-#include <sys/param.h>
-#include <sys/kernel.h>
-//#include <sys/libkern.h>
-#include <sys/systm.h>
-
-#include <sys/sysproto.h>
-//#include <sys/unistd.h>
-#include <sys/syscallsubr.h>
-
 #include <ps4/kern.h>
 
-#define	STDIN_FILENO 0
+#ifndef STDOUT_FILENO
+	#define	STDOUT_FILENO 1
+#endif
 
 int main(int argc, char **argv)
 {
@@ -27,7 +12,7 @@ int main(int argc, char **argv)
 	int r;
 
 	td = ps4KernThreadCurrent();
-	r = ps4KernUtilFilePrint(td, STDIN_FILENO, "Hello world from your ps4 kernel, ps4sdk and hito <3\n{main:%p, argc:%i, argv[0]:%s}\n", main, argc, argv[0]);
+	r = ps4KernUtilFilePrint(td, STDOUT_FILENO, "Hello world from your ps4 kernel, ps4sdk.\nKind regards hito <3\n\n{main:%p, argc:%i, argv[0]:%s}\n", main, argc, argv[0]);
 
 	return r;
 }

kern/server_hello_world/source/main.c

@@ -5,16 +5,34 @@
 #define _WANT_UCRED
 #include <sys/cdefs.h>
 #include <sys/types.h>
+#include <sys/limits.h>
 #include <sys/param.h>
 #include <sys/kernel.h>
 //#include <sys/libkern.h>
 #include <sys/systm.h>
+
+#include <sys/sysproto.h>
+//#include <sys/unistd.h>
 #include <sys/syscallsubr.h>
 
 #include <ps4/kern.h>
 
 #define SERVER_PORT 5057
 
+#ifndef STDOUT_FILENO
+	#define	STDOUT_FILENO 1
+#endif
+
+static int c;
+
+//int printf(const char *fmt, ...)
+int printf_hook(void *td, Ps4KernFunctionHookArgument *uap)
+{
+	// fully variadic maybe on the next season of ps4sdk
+	ps4KernUtilSocketPrint(td, c, (const char *)uap->arguments->general[1]);
+	return PS4_KERN_FUNCTION_HOOK_CONTINUE;
+}
+
 int main(int argc, char **argv)
 {
 	// send this elf to 5054, connect, see connection get closed
@@ -23,8 +41,25 @@ int main(int argc, char **argv)
 	int client;
 
 	td = ps4KernThreadCurrent();
-	client = ps4KernUtilServerCreateSingleAccept(td, SERVER_PORT);
-	ps4KernUtilSocketPrint(td, client, "Hello world from your ps4 kernel, ps4sdk and hito <3\n{main:%p, argc:%i, argv[0]:%s}\n", main, argc, argv[0]);
+	client = ps4KernUtilServerCreateSingleAccept(td, SERVER_PORT); // see kern/util for more
+
+	ps4KernUtilSocketPrint(td, client, "Hello world from your ps4 kernel and ps4sdk.\n{main:%p, argc:%i, argv[0]:%s}\n\n", main, argc, argv[0]);
+
+	//(you will need to (re)connect 5052 if you send this to 5054)
+	//(without messing with the redirected, the rest works as intended)
+	//(basically you hijack the user fd and the userland starts interfering)
+	//ps4KernUtilStandardIoRedirectPlain(td, client);
+	//ps4KernUtilFilePrint(td, STDOUT_FILENO, "Somebody is watching over us... controlling us. It's true, I tell you. It's true! We are merely sprites that dance at the beck and call of our button-pressing overlord. This is a video game. Don't you see? We are characters in a video game!\n\n");
+
+	c = client;
+	printf("S.T.A.R.S ... !\n"); // the kernel printf does not go to an fd
+	ps4KernFunctionHookSized((void *)ps4KernDlSym("printf"), (void *)printf_hook, 16); // 16 is a valid instruction offset in printf !!!
+	printf("It's a weapon. It's really powerful, especially against living things.\n\n");
+	ps4KernFunctionUnhook((void *)ps4KernDlSym("printf"));
+	printf("S.T.A.R.S ... !\n");
+
+	ps4KernUtilSocketPrint(td, client, "Kind regards and greetings to all who read this <3,\nhito\n");
+
 	ps4KernUtilSocketClose(td, client);
 
 	return 0;