sigtrap and TF

[ninjaboy <n0b0dyn1nj4@xxxxxxxxx>]

Hi folks,

why if i put TF in my prog and install an handler to SIGTRAP the
handler is not caught?
this is the test code:
.data

str:
        .string "fuck\n\n"

.text
.globl suck

suck:

        nop
        pushf
        xor %rax, %rax
        pop %rax
        orq $0x100, %rax
        pushq %rax
        popf
        nop
        nop
        movq $str, %rdi
        movq $0, %rax
        call printf
        call exit

and the main is:

#include <stdio.h>
#include <signal.h>

int i=0;

void
handler(int n) {

        i=1;
}

void
install_sigtrap_handler() {

        struct sigaction sa;
        sa.sa_sigaction = handler;
        sa.sa_flags = SA_SIGINFO | SA_RESTART | SA_NODEFER;
        sigemptyset(&sa.sa_mask);

        if(sigaction(SIGTRAP, &sa, NULL))
                printf("sigaction error\n");
}


void
test_trap() {

    __asm__ __volatile__ ( "int3\n\t");

}

int
main() {

        install_sigtrap_handler();
//      signal(SIGTRAP, handler);
//      test_trap();
        suck();

        if(i)
                printf("ok\n");
}

thanks.

-- 
noone is alone.

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