// SPDX-License-Identifier: GPL-2.0
/*
 * User Events ABI Test Program
 *
 * Copyright (c) 2022 Beau Belgrave <beaub@linux.microsoft.com>
 */

#define _GNU_SOURCE
#include <sched.h>

#include <errno.h>
#include <linux/user_events.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <glob.h>
#include <string.h>
#include <asm/unistd.h>

#include "kselftest_harness.h"
#include "user_events_selftests.h"

const char *data_file = "/sys/kernel/tracing/user_events_data";
const char *enable_file = "/sys/kernel/tracing/events/user_events/__abi_event/enable";
const char *multi_dir_glob = "/sys/kernel/tracing/events/user_events_multi/__abi_event.*";

static int wait_for_delete(char *dir)
{
        struct stat buf;
        int i;

        for (i = 0; i < 10000; ++i) {
                if (stat(dir, &buf) == -1 && errno == ENOENT)
                        return 0;

                usleep(1000);
        }

        return -1;
}

static int find_multi_event_dir(char *unique_field, char *out_dir, int dir_len)
{
        char path[256];
        glob_t buf;
        int i, ret;

        ret = glob(multi_dir_glob, GLOB_ONLYDIR, NULL, &buf);

        if (ret)
                return -1;

        ret = -1;

        for (i = 0; i < buf.gl_pathc; ++i) {
                FILE *fp;

                snprintf(path, sizeof(path), "%s/format", buf.gl_pathv[i]);
                fp = fopen(path, "r");

                if (!fp)
                        continue;

                while (fgets(path, sizeof(path), fp) != NULL) {
                        if (strstr(path, unique_field)) {
                                fclose(fp);
                                /* strscpy is not available, use snprintf */
                                snprintf(out_dir, dir_len, "%s", buf.gl_pathv[i]);
                                ret = 0;
                                goto out;
                        }
                }

                fclose(fp);
        }
out:
        globfree(&buf);

        return ret;
}

static bool event_exists(void)
{
        int fd = open(enable_file, O_RDWR);

        if (fd < 0)
                return false;

        close(fd);

        return true;
}

static int change_event(bool enable)
{
        int fd = open(enable_file, O_RDWR);
        int ret;

        if (fd < 0)
                return -1;

        if (enable)
                ret = write(fd, "1", 1);
        else
                ret = write(fd, "0", 1);

        close(fd);

        if (ret == 1)
                ret = 0;
        else
                ret = -1;

        return ret;
}

static int event_delete(void)
{
        int fd = open(data_file, O_RDWR);
        int ret;

        if (fd < 0)
                return -1;

        ret = ioctl(fd, DIAG_IOCSDEL, "__abi_event");

        close(fd);

        return ret;
}

static int reg_enable_multi(void *enable, int size, int bit, int flags,
                            char *args)
{
        struct user_reg reg = {0};
        char full_args[512] = {0};
        int fd = open(data_file, O_RDWR);
        int len;
        int ret;

        if (fd < 0)
                return -1;

        len = snprintf(full_args, sizeof(full_args), "__abi_event %s", args);

        if (len > sizeof(full_args)) {
                ret = -E2BIG;
                goto out;
        }

        reg.size = sizeof(reg);
        reg.name_args = (__u64)full_args;
        reg.flags = USER_EVENT_REG_MULTI_FORMAT | flags;
        reg.enable_bit = bit;
        reg.enable_addr = (__u64)enable;
        reg.enable_size = size;

        ret = ioctl(fd, DIAG_IOCSREG, &reg);
out:
        close(fd);

        return ret;
}

static int reg_enable_flags(void *enable, int size, int bit, int flags)
{
        struct user_reg reg = {0};
        int fd = open(data_file, O_RDWR);
        int ret;

        if (fd < 0)
                return -1;

        reg.size = sizeof(reg);
        reg.name_args = (__u64)"__abi_event";
        reg.flags = flags;
        reg.enable_bit = bit;
        reg.enable_addr = (__u64)enable;
        reg.enable_size = size;

        ret = ioctl(fd, DIAG_IOCSREG, &reg);

        close(fd);

        return ret;
}

static int reg_enable(void *enable, int size, int bit)
{
        return reg_enable_flags(enable, size, bit, 0);
}

static int reg_disable(void *enable, int bit)
{
        struct user_unreg reg = {0};
        int fd = open(data_file, O_RDWR);
        int ret;

        if (fd < 0)
                return -1;

        reg.size = sizeof(reg);
        reg.disable_bit = bit;
        reg.disable_addr = (__u64)enable;

        ret = ioctl(fd, DIAG_IOCSUNREG, &reg);

        close(fd);

        return ret;
}

FIXTURE(user) {
        int check;
        long check_long;
        bool umount;
};

FIXTURE_SETUP(user) {
        USER_EVENT_FIXTURE_SETUP(return, self->umount);

        change_event(false);
        self->check = 0;
        self->check_long = 0;
}

FIXTURE_TEARDOWN(user) {
        USER_EVENT_FIXTURE_TEARDOWN(self->umount);
}

TEST_F(user, enablement) {
        /* Changes should be reflected immediately */
        ASSERT_EQ(0, self->check);
        ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0));
        ASSERT_EQ(0, change_event(true));
        ASSERT_EQ(1, self->check);
        ASSERT_EQ(0, change_event(false));
        ASSERT_EQ(0, self->check);

        /* Ensure kernel clears bit after disable */
        ASSERT_EQ(0, change_event(true));
        ASSERT_EQ(1, self->check);
        ASSERT_EQ(0, reg_disable(&self->check, 0));
        ASSERT_EQ(0, self->check);

        /* Ensure doesn't change after unreg */
        ASSERT_EQ(0, change_event(true));
        ASSERT_EQ(0, self->check);
        ASSERT_EQ(0, change_event(false));
}

TEST_F(user, flags) {
        /* USER_EVENT_REG_PERSIST is allowed */
        ASSERT_EQ(0, reg_enable_flags(&self->check, sizeof(int), 0,
                                      USER_EVENT_REG_PERSIST));
        ASSERT_EQ(0, reg_disable(&self->check, 0));

        /* Ensure it exists after close and disable */
        ASSERT_TRUE(event_exists());

        /* Ensure we can delete it */
        ASSERT_EQ(0, event_delete());

        /* USER_EVENT_REG_MAX or above is not allowed */
        ASSERT_EQ(-1, reg_enable_flags(&self->check, sizeof(int), 0,
                                       USER_EVENT_REG_MAX));

        /* Ensure it does not exist after invalid flags */
        ASSERT_FALSE(event_exists());
}

TEST_F(user, bit_sizes) {
        /* Allow 0-31 bits for 32-bit */
        ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0));
        ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 31));
        ASSERT_NE(0, reg_enable(&self->check, sizeof(int), 32));
        ASSERT_EQ(0, reg_disable(&self->check, 0));
        ASSERT_EQ(0, reg_disable(&self->check, 31));

#if BITS_PER_LONG == 8
        /* Allow 0-64 bits for 64-bit */
        ASSERT_EQ(0, reg_enable(&self->check_long, sizeof(long), 63));
        ASSERT_NE(0, reg_enable(&self->check_long, sizeof(long), 64));
        ASSERT_EQ(0, reg_disable(&self->check_long, 63));
#endif

        /* Disallowed sizes (everything beside 4 and 8) */
        ASSERT_NE(0, reg_enable(&self->check, 1, 0));
        ASSERT_NE(0, reg_enable(&self->check, 2, 0));
        ASSERT_NE(0, reg_enable(&self->check, 3, 0));
        ASSERT_NE(0, reg_enable(&self->check, 5, 0));
        ASSERT_NE(0, reg_enable(&self->check, 6, 0));
        ASSERT_NE(0, reg_enable(&self->check, 7, 0));
        ASSERT_NE(0, reg_enable(&self->check, 9, 0));
        ASSERT_NE(0, reg_enable(&self->check, 128, 0));
}

TEST_F(user, multi_format) {
        char first_dir[256];
        char second_dir[256];
        struct stat buf;

        /* Multiple formats for the same name should work */
        ASSERT_EQ(0, reg_enable_multi(&self->check, sizeof(int), 0,
                                      0, "u32 multi_first"));

        ASSERT_EQ(0, reg_enable_multi(&self->check, sizeof(int), 1,
                                      0, "u64 multi_second"));

        /* Same name with same format should also work */
        ASSERT_EQ(0, reg_enable_multi(&self->check, sizeof(int), 2,
                                      0, "u64 multi_second"));

        ASSERT_EQ(0, find_multi_event_dir("multi_first",
                                          first_dir, sizeof(first_dir)));

        ASSERT_EQ(0, find_multi_event_dir("multi_second",
                                          second_dir, sizeof(second_dir)));

        /* Should not be found in the same dir */
        ASSERT_NE(0, strcmp(first_dir, second_dir));

        /* First dir should still exist */
        ASSERT_EQ(0, stat(first_dir, &buf));

        /* Disabling first register should remove first dir */
        ASSERT_EQ(0, reg_disable(&self->check, 0));
        ASSERT_EQ(0, wait_for_delete(first_dir));

        /* Second dir should still exist */
        ASSERT_EQ(0, stat(second_dir, &buf));

        /* Disabling second register should remove second dir */
        ASSERT_EQ(0, reg_disable(&self->check, 1));
        /* Ensure bit 1 and 2 are tied together, should not delete yet */
        ASSERT_EQ(0, stat(second_dir, &buf));
        ASSERT_EQ(0, reg_disable(&self->check, 2));
        ASSERT_EQ(0, wait_for_delete(second_dir));
}

TEST_F(user, forks) {
        int i;

        /* Ensure COW pages get updated after fork */
        ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0));
        ASSERT_EQ(0, self->check);

        if (fork() == 0) {
                /* Force COW */
                self->check = 0;

                /* Up to 1 sec for enablement */
                for (i = 0; i < 10; ++i) {
                        usleep(100000);

                        if (self->check)
                                exit(0);
                }

                exit(1);
        }

        /* Allow generous time for COW, then enable */
        usleep(100000);
        ASSERT_EQ(0, change_event(true));

        ASSERT_NE(-1, wait(&i));
        ASSERT_EQ(0, WEXITSTATUS(i));

        /* Ensure child doesn't disable parent */
        if (fork() == 0)
                exit(reg_disable(&self->check, 0));

        ASSERT_NE(-1, wait(&i));
        ASSERT_EQ(0, WEXITSTATUS(i));
        ASSERT_EQ(1, self->check);
        ASSERT_EQ(0, change_event(false));
        ASSERT_EQ(0, self->check);
}

/* Waits up to 1 sec for enablement */
static int clone_check(void *check)
{
        int i;

        for (i = 0; i < 10; ++i) {
                usleep(100000);

                if (*(int *)check)
                        return 0;
        }

        return 1;
}

TEST_F(user, clones) {
        int i, stack_size = 4096;
        void *stack = mmap(NULL, stack_size, PROT_READ | PROT_WRITE,
                           MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK,
                           -1, 0);

        ASSERT_NE(MAP_FAILED, stack);
        ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0));
        ASSERT_EQ(0, self->check);

        /* Shared VM should see enablements */
        ASSERT_NE(-1, clone(&clone_check, stack + stack_size,
                            CLONE_VM | SIGCHLD, &self->check));

        ASSERT_EQ(0, change_event(true));
        ASSERT_NE(-1, wait(&i));
        ASSERT_EQ(0, WEXITSTATUS(i));
        munmap(stack, stack_size);
        ASSERT_EQ(0, change_event(false));
}

int main(int argc, char **argv)
{
        return test_harness_run(argc, argv);
}