iPXE
Functions
nulltrap.c File Reference
#include <stdint.h>
#include <stdio.h>

Go to the source code of this file.

Functions

 __attribute__ ((noreturn, section(".text.null_trap")))

Function Documentation

__attribute__ ( (noreturn, section(".text.null_trap"))  )

Definition at line 4 of file nulltrap.c.

References __asm__(), DBG_HD, and printf().

                                 {
        void *stack;

        /* 128 bytes of NOPs; the idea of this is that if something
         * dereferences a NULL pointer and overwrites us, we at least
         * have some chance of still getting to execute the printf()
         * statement.
         */
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );
        __asm__ __volatile__ ( "nop ; nop ; nop ; nop" );

        __asm__ __volatile__ ( "movl %%esp, %0" : "=r" ( stack ) );
        printf ( "NULL method called from %p (stack %p)\n", 
                 __builtin_return_address ( 0 ), stack );
        DBG_HD ( stack, 256 );
        while ( 1 ) {}
}