// SPDX-License-Identifier: GPL-2.0
/*
 * ioperm.c - Test case for ioperm(2)
 * Copyright (c) 2015 Andrew Lutomirski
 */

#define _GNU_SOURCE
#include <err.h>
#include <stdio.h>
#include <stdint.h>
#include <signal.h>
#include <setjmp.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdbool.h>
#include <sched.h>
#include <sys/io.h>

static int nerrs = 0;

static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
                       int flags)
{
        struct sigaction sa;
        memset(&sa, 0, sizeof(sa));
        sa.sa_sigaction = handler;
        sa.sa_flags = SA_SIGINFO | flags;
        sigemptyset(&sa.sa_mask);
        if (sigaction(sig, &sa, 0))
                err(1, "sigaction");

}

static void clearhandler(int sig)
{
        struct sigaction sa;
        memset(&sa, 0, sizeof(sa));
        sa.sa_handler = SIG_DFL;
        sigemptyset(&sa.sa_mask);
        if (sigaction(sig, &sa, 0))
                err(1, "sigaction");
}

static jmp_buf jmpbuf;

static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
{
        siglongjmp(jmpbuf, 1);
}

static bool try_outb(unsigned short port)
{
        sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
        if (sigsetjmp(jmpbuf, 1) != 0) {
                return false;
        } else {
                asm volatile ("outb %%al, %w[port]"
                              : : [port] "Nd" (port), "a" (0));
                return true;
        }
        clearhandler(SIGSEGV);
}

static void expect_ok(unsigned short port)
{
        if (!try_outb(port)) {
                printf("[FAIL]\toutb to 0x%02hx failed\n", port);
                exit(1);
        }

        printf("[OK]\toutb to 0x%02hx worked\n", port);
}

static void expect_gp(unsigned short port)
{
        if (try_outb(port)) {
                printf("[FAIL]\toutb to 0x%02hx worked\n", port);
                exit(1);
        }

        printf("[OK]\toutb to 0x%02hx failed\n", port);
}

int main(void)
{
        cpu_set_t cpuset;
        CPU_ZERO(&cpuset);
        CPU_SET(0, &cpuset);
        if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
                err(1, "sched_setaffinity to CPU 0");

        expect_gp(0x80);
        expect_gp(0xed);

        /*
         * Probe for ioperm support.  Note that clearing ioperm bits
         * works even as nonroot.
         */
        printf("[RUN]\tenable 0x80\n");
        if (ioperm(0x80, 1, 1) != 0) {
                printf("[OK]\tioperm(0x80, 1, 1) failed (%d) -- try running as root\n",
                       errno);
                return 0;
        }
        expect_ok(0x80);
        expect_gp(0xed);

        printf("[RUN]\tdisable 0x80\n");
        if (ioperm(0x80, 1, 0) != 0) {
                printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
                return 1;
        }
        expect_gp(0x80);
        expect_gp(0xed);

        /* Make sure that fork() preserves ioperm. */
        if (ioperm(0x80, 1, 1) != 0) {
                printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
                return 1;
        }

        pid_t child = fork();
        if (child == -1)
                err(1, "fork");

        if (child == 0) {
                printf("[RUN]\tchild: check that we inherited permissions\n");
                expect_ok(0x80);
                expect_gp(0xed);
                printf("[RUN]\tchild: Extend permissions to 0x81\n");
                if (ioperm(0x81, 1, 1) != 0) {
                        printf("[FAIL]\tioperm(0x81, 1, 1) failed (%d)", errno);
                        return 1;
                }
                printf("[RUN]\tchild: Drop permissions to 0x80\n");
                if (ioperm(0x80, 1, 0) != 0) {
                        printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
                        return 1;
                }
                expect_gp(0x80);
                return 0;
        } else {
                int status;
                if (waitpid(child, &status, 0) != child ||
                    !WIFEXITED(status)) {
                        printf("[FAIL]\tChild died\n");
                        nerrs++;
                } else if (WEXITSTATUS(status) != 0) {
                        printf("[FAIL]\tChild failed\n");
                        nerrs++;
                } else {
                        printf("[OK]\tChild succeeded\n");
                }
        }

        /* Verify that the child dropping 0x80 did not affect the parent */
        printf("\tVerify that unsharing the bitmap worked\n");
        expect_ok(0x80);

        /* Test the capability checks. */
        printf("\tDrop privileges\n");
        if (setresuid(1, 1, 1) != 0) {
                printf("[WARN]\tDropping privileges failed\n");
                return 0;
        }

        printf("[RUN]\tdisable 0x80\n");
        if (ioperm(0x80, 1, 0) != 0) {
                printf("[FAIL]\tioperm(0x80, 1, 0) failed (%d)", errno);
                return 1;
        }
        printf("[OK]\tit worked\n");

        printf("[RUN]\tenable 0x80 again\n");
        if (ioperm(0x80, 1, 1) == 0) {
                printf("[FAIL]\tit succeeded but should have failed.\n");
                return 1;
        }
        printf("[OK]\tit failed\n");
        return 0;
}