This adds a new c program skas-or-tt mostly from uml code which

automates the recognition of whether or not the host kernel has the
skas patch applied.  Makefile edits itself, and all gui is automated.

skas-or-tt/Makefile

@@ -0,0 +1,19 @@
+CC=gcc
+CFLAGS=-Wall -O2
+
+SRC=skas-or-tt.c
+OBJS=$(patsubst %.c,%.o, $(SRC))
+
+
+all: skas-or-tt 
+
+skas-or-tt: $(OBJS)
+	$(CC) $(CFLAGS) -o $@ $(OBJS) -o $@
+
+$(OBJS): %.o : %.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+$(OBJS): Makefile
+
+clean:
+	rm -f *.o *.a core skas-or-tt 

skas-or-tt/skas-or-tt.c

@@ -0,0 +1,141 @@
+/* 
+skas_or_tt Copyright (C) 2003  
+Jonathan Rosenbaum <freesource@users.sourceforge.net>
+
+A program to check for the existence of the skas patch in the host
+kernel and /proc/mm.  Basically borrowed/simplified from jdike's
+process.c.  This is a good way to learn about clone() and ptrace().
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+#include <wait.h>
+#include <sys/mman.h>  /* for mmap */
+#include <sys/ptrace.h>
+#include <sys/types.h>
+#include <sched.h>  /* clone */
+#define PTRACE_FAULTINFO 52
+#define PAGE_SIZE 1024
+
+int main(void)
+{
+
+  int n, pid, ret = 1;
+  void *stack;
+ 
+  struct ptrace_faultinfo {
+	  int is_write;
+	  unsigned long addr;
+  };
+  
+
+  struct ptrace_faultinfo fi;
+
+  printf("Checking for the skas3 patch in the host...");
+  pid = start_ptraced_child(&stack);
+
+  n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
+  if(n < 0){
+	  if(errno == EIO) 
+		  printf("not found\n");
+	  else printf("No (unexpected errno - %d)\n", errno);
+	  ret = 0;
+	}
+  else  printf("found\n");
+  
+
+  printf("Checking for /proc/mm...");
+  if(access("/proc/mm", W_OK)){
+	  printf("not found\n");
+	  ret = 0;
+  }
+  else printf("found\n");
+
+  kill(pid, SIGKILL);
+  return(ret);
+
+}
+
+
+int threadFunction( void* argument )
+{
+         printf( "child thread exiting\n" );
+	 exit(0);
+}
+
+
+int os_getpid(void)
+{
+	return(getpid());
+}
+
+void os_stop_process(int pid)
+{
+	kill(pid, SIGSTOP);
+}
+
+void os_kill_process(int pid, int reap_child)
+{
+	kill(pid, SIGKILL);
+	if(reap_child)
+		waitpid(pid, NULL, 0);
+		
+}
+
+static int ptrace_child(void *arg)
+{
+	int pid = os_getpid(); 
+
+	if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){
+		perror("ptrace");
+		os_kill_process(pid, 0);
+	}
+
+	os_stop_process(pid);
+	_exit(os_getpid() == pid);
+
+}
+
+
+int start_ptraced_child(void **stack_out)
+{
+	void *stack;
+	unsigned long sp;
+	int pid, n, status;
+	
+	stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
+		     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	if(stack == MAP_FAILED)
+	        printf("check_ptrace : mmap failed, errno = %d", errno);
+	sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
+	pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
+	if(pid < 0) {
+		printf("check_ptrace : clone failed, errno = %d\n", errno);
+		exit(0);
+	}
+	n = waitpid(pid, &status, WUNTRACED);
+	if(n < 0) {
+		printf("check_ptrace : wait failed, errno = %d\n", errno);
+		exit(0);
+	}
+	if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) {
+		printf("check_ptrace : expected SIGSTOP, got status = %d\n",
+		      status);
+		exit(0);
+	}
+	*stack_out = stack;
+	return(pid);
+}
+
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-file-style: "linux"
+ * End:
+ */