// tracer2.c
#include <stdio.h>
#include <stdlib.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <sys/user.h>
#include <unistd.h>

int main(int argc, char **argv) {
    pid_t child = fork();
    if (child == 0) {
        ptrace(PTRACE_TRACEME, 0, 0, 0);
        raise(SIGSTOP);
        execv(argv[1], &argv[1]);
        perror("exec");
        exit(1);
    }

    int status;
    waitpid(child, &status, 0);

    // Use TRACEEXEC to catch the exec, then CONT (not SYSCALL)
    ptrace(PTRACE_SETOPTIONS, child, 0, PTRACE_O_TRACEEXEC);
    ptrace(PTRACE_CONT, child, 0, 0);

    FILE *log = fopen("/tmp/signal_trace.txt", "w");
    int count = 0;

    while (1) {
        waitpid(child, &status, 0);

        if (WIFEXITED(status)) {
            fprintf(log, "Exited: %d (signals: %d)\n", WEXITSTATUS(status), count);
            break;
        }
        if (WIFSIGNALED(status)) {
            fprintf(log, "Killed by signal %d\n", WTERMSIG(status));
            break;
        }
        if (WIFSTOPPED(status)) {
            int sig = WSTOPSIG(status);

            // Exec event — swallow, continue
            if (status >> 8 == (SIGTRAP | (PTRACE_EVENT_EXEC << 8))) {
                fprintf(log, "Exec event\n");
                ptrace(PTRACE_CONT, child, 0, 0);
                continue;
            }

            struct user_regs_struct regs;
            ptrace(PTRACE_GETREGS, child, 0, &regs);
            fprintf(log, "Signal %2d at RIP=0x%llx RDI=%lld RSI=0x%llx\n",
                    sig, regs.rip, regs.rdi, regs.rsi);
            fflush(log);
            count++;

            // Forward the signal
            ptrace(PTRACE_CONT, child, 0, sig);
        }
    }

    fclose(log);
    return 0;
}