#include "libc.h"
#include <errno.h>
#include <signal.h>
#include <spawn.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>

int system(const char* cmd) {
    pid_t pid;
    sigset_t old, reset;
    struct sigaction sa = {.sa_handler = SIG_IGN}, oldint, oldquit;
    int status = 0x7f00, ret;
    posix_spawnattr_t attr;

    if (!cmd)
        return 1;

    sigaction(SIGINT, &sa, &oldint);
    sigaction(SIGQUIT, &sa, &oldquit);
    sigaddset(&sa.sa_mask, SIGCHLD);
    sigprocmask(SIG_BLOCK, &sa.sa_mask, &old);

    sigemptyset(&reset);
    if (oldint.sa_handler != SIG_IGN)
        sigaddset(&reset, SIGINT);
    if (oldquit.sa_handler != SIG_IGN)
        sigaddset(&reset, SIGQUIT);
    posix_spawnattr_init(&attr);
    posix_spawnattr_setsigmask(&attr, &old);
    posix_spawnattr_setsigdefault(&attr, &reset);
    posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETSIGDEF | POSIX_SPAWN_SETSIGMASK);
    ret = posix_spawn(&pid, "/bin/sh", 0, &attr, (char* []){(char*)"sh", (char*)"-c", (char*)cmd, 0}, __environ);
    posix_spawnattr_destroy(&attr);

    if (!ret)
        while (waitpid(pid, &status, 0) < 0 && errno == EINTR)
            ;
    sigaction(SIGINT, &oldint, NULL);
    sigaction(SIGQUIT, &oldquit, NULL);
    sigprocmask(SIG_SETMASK, &old, NULL);

    if (ret)
        errno = ret;
    return status;
}