Ejemplo n.º 1
0
int grab_pid(pid_t pid, struct ptrace_child *child, child_addr_t *scratch) {
    int err;

    if (ptrace_attach_child(child, pid)) {
        err = child->error;
        goto out;
    }
    if (ptrace_advance_to_state(child, ptrace_at_syscall)) {
        err = child->error;
        goto out;
    }
    if (ptrace_save_regs(child)) {
        err = child->error;
        goto out;
    }

    if ((err = mmap_scratch(child, scratch)))
        goto out_restore_regs;

    return 0;

out_restore_regs:
    ptrace_restore_regs(child);

out:
    ptrace_detach_child(child);

    return err;
}
Ejemplo n.º 2
0
int attach_child(pid_t pid, const char *pty, int force_stdio) {
    struct ptrace_child child;
    unsigned long scratch_page = -1;
    int *child_tty_fds = NULL, n_fds, child_fd, statfd;
    int i;
    int err = 0;
    long page_size = sysconf(_SC_PAGE_SIZE);
    char stat_path[PATH_MAX];
    long mmap_syscall;

    if ((err = copy_tty_state(pid, pty))) {
        if (err == ENOTTY && !force_stdio) {
            error("Target is not connected to a terminal.\n"
                  "    Use -s to force attaching anyways.");
            return err;
        }
    }

    snprintf(stat_path, sizeof stat_path, "/proc/%d/stat", pid);
    statfd = open(stat_path, O_RDONLY);
    if (statfd < 0) {
        error("Unable to open %s: %s", stat_path, strerror(errno));
        return -statfd;
    }

    kill(pid, SIGTSTP);
    wait_for_stop(pid, statfd);

    if (ptrace_attach_child(&child, pid)) {
        err = child.error;
        goto out_cont;
    }

    if (ptrace_advance_to_state(&child, ptrace_at_syscall)) {
        err = child.error;
        goto out_detach;
    }
    if (ptrace_save_regs(&child)) {
        err = child.error;
        goto out_detach;
    }

    mmap_syscall = ptrace_syscall_numbers(&child)->nr_mmap2;
    if (mmap_syscall == -1)
        mmap_syscall = ptrace_syscall_numbers(&child)->nr_mmap;
    scratch_page = ptrace_remote_syscall(&child, mmap_syscall, 0,
                                         page_size, PROT_READ|PROT_WRITE,
                                         MAP_ANONYMOUS|MAP_PRIVATE, 0, 0);

    if (scratch_page > (unsigned long)-1000) {
        err = -(signed long)scratch_page;
        goto out_unmap;
    }

    debug("Allocated scratch page: %lx", scratch_page);

    if (force_stdio) {
        child_tty_fds = malloc(3 * sizeof(int));
        if (!child_tty_fds) {
            err = ENOMEM;
            goto out_unmap;
        }
        n_fds = 3;
        child_tty_fds[0] = 0;
        child_tty_fds[1] = 1;
        child_tty_fds[2] = 2;
    } else {
        child_tty_fds = get_child_tty_fds(&child, statfd, &n_fds);
        if (!child_tty_fds) {
            err = child.error;
            goto out_unmap;
        }
    }

    if (ptrace_memcpy_to_child(&child, scratch_page, pty, strlen(pty)+1)) {
        err = child.error;
        error("Unable to memcpy the pty path to child.");
        goto out_free_fds;
    }

    child_fd = do_syscall(&child, open,
                          scratch_page, O_RDWR|O_NOCTTY,
                          0, 0, 0, 0);
    if (child_fd < 0) {
        err = child_fd;
        error("Unable to open the tty in the child.");
        goto out_free_fds;
    }

    debug("Opened the new tty in the child: %d", child_fd);

    err = ignore_hup(&child, scratch_page);
    if (err < 0)
        goto out_close;

    err = do_syscall(&child, getsid, 0, 0, 0, 0, 0, 0);
    if (err != child.pid) {
        debug("Target is not a session leader, attempting to setsid.");
        err = do_setsid(&child);
    } else {
        do_syscall(&child, ioctl, child_tty_fds[0], TIOCNOTTY, 0, 0, 0, 0);
    }
    if (err < 0)
        goto out_close;

    err = do_syscall(&child, ioctl, child_fd, TIOCSCTTY, 0, 0, 0, 0);
    if (err < 0) {
        error("Unable to set controlling terminal.");
        goto out_close;
    }

    debug("Set the controlling tty");

    for (i = 0; i < n_fds; i++)
        do_syscall(&child, dup2, child_fd, child_tty_fds[i], 0, 0, 0, 0);


    err = 0;

 out_close:
    do_syscall(&child, close, child_fd, 0, 0, 0, 0, 0);
 out_free_fds:
    free(child_tty_fds);

 out_unmap:
    do_unmap(&child, scratch_page, page_size);

    ptrace_restore_regs(&child);
 out_detach:
    ptrace_detach_child(&child);

    if (err == 0) {
        kill(child.pid, SIGSTOP);
        wait_for_stop(child.pid, statfd);
    }
    kill(child.pid, SIGWINCH);
 out_cont:
    kill(child.pid, SIGCONT);
    close(statfd);

    return err < 0 ? -err : err;
}