/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (c) 2022-2024 Red Hat */

#include "kselftest_harness.h"

#include <fcntl.h>
#include <fnmatch.h>
#include <dirent.h>
#include <poll.h>
#include <pthread.h>
#include <stdbool.h>
#include <linux/hidraw.h>
#include <linux/uhid.h>

#define SHOW_UHID_DEBUG 0

#define min(a, b) \
        ({ __typeof__(a) _a = (a); \
        __typeof__(b) _b = (b); \
        _a < _b ? _a : _b; })

struct uhid_device {
        int dev_id;             /* uniq (random) number to identify the device */
        int uhid_fd;
        int hid_id;             /* HID device id in the system */
        __u16 bus;
        __u32 vid;
        __u32 pid;
        pthread_t tid;          /* thread for reading uhid events */
};

static unsigned char rdesc[] = {
        0x06, 0x00, 0xff,       /* Usage Page (Vendor Defined Page 1) */
        0x09, 0x21,             /* Usage (Vendor Usage 0x21) */
        0xa1, 0x01,             /* COLLECTION (Application) */
        0x09, 0x01,                     /* Usage (Vendor Usage 0x01) */
        0xa1, 0x00,                     /* COLLECTION (Physical) */
        0x85, 0x02,                             /* REPORT_ID (2) */
        0x19, 0x01,                             /* USAGE_MINIMUM (1) */
        0x29, 0x08,                             /* USAGE_MAXIMUM (3) */
        0x15, 0x00,                             /* LOGICAL_MINIMUM (0) */
        0x25, 0xff,                             /* LOGICAL_MAXIMUM (255) */
        0x95, 0x08,                             /* REPORT_COUNT (8) */
        0x75, 0x08,                             /* REPORT_SIZE (8) */
        0x81, 0x02,                             /* INPUT (Data,Var,Abs) */
        0xc0,                           /* END_COLLECTION */
        0x09, 0x01,                     /* Usage (Vendor Usage 0x01) */
        0xa1, 0x00,                     /* COLLECTION (Physical) */
        0x85, 0x01,                             /* REPORT_ID (1) */
        0x06, 0x00, 0xff,                       /* Usage Page (Vendor Defined Page 1) */
        0x19, 0x01,                             /* USAGE_MINIMUM (1) */
        0x29, 0x03,                             /* USAGE_MAXIMUM (3) */
        0x15, 0x00,                             /* LOGICAL_MINIMUM (0) */
        0x25, 0x01,                             /* LOGICAL_MAXIMUM (1) */
        0x95, 0x03,                             /* REPORT_COUNT (3) */
        0x75, 0x01,                             /* REPORT_SIZE (1) */
        0x81, 0x02,                             /* INPUT (Data,Var,Abs) */
        0x95, 0x01,                             /* REPORT_COUNT (1) */
        0x75, 0x05,                             /* REPORT_SIZE (5) */
        0x81, 0x01,                             /* INPUT (Cnst,Var,Abs) */
        0x05, 0x01,                             /* USAGE_PAGE (Generic Desktop) */
        0x09, 0x30,                             /* USAGE (X) */
        0x09, 0x31,                             /* USAGE (Y) */
        0x15, 0x81,                             /* LOGICAL_MINIMUM (-127) */
        0x25, 0x7f,                             /* LOGICAL_MAXIMUM (127) */
        0x75, 0x10,                             /* REPORT_SIZE (16) */
        0x95, 0x02,                             /* REPORT_COUNT (2) */
        0x81, 0x06,                             /* INPUT (Data,Var,Rel) */

        0x06, 0x00, 0xff,                       /* Usage Page (Vendor Defined Page 1) */
        0x19, 0x01,                             /* USAGE_MINIMUM (1) */
        0x29, 0x03,                             /* USAGE_MAXIMUM (3) */
        0x15, 0x00,                             /* LOGICAL_MINIMUM (0) */
        0x25, 0x01,                             /* LOGICAL_MAXIMUM (1) */
        0x95, 0x03,                             /* REPORT_COUNT (3) */
        0x75, 0x01,                             /* REPORT_SIZE (1) */
        0x91, 0x02,                             /* Output (Data,Var,Abs) */
        0x95, 0x01,                             /* REPORT_COUNT (1) */
        0x75, 0x05,                             /* REPORT_SIZE (5) */
        0x91, 0x01,                             /* Output (Cnst,Var,Abs) */

        0x06, 0x00, 0xff,                       /* Usage Page (Vendor Defined Page 1) */
        0x19, 0x06,                             /* USAGE_MINIMUM (6) */
        0x29, 0x08,                             /* USAGE_MAXIMUM (8) */
        0x15, 0x00,                             /* LOGICAL_MINIMUM (0) */
        0x25, 0x01,                             /* LOGICAL_MAXIMUM (1) */
        0x95, 0x03,                             /* REPORT_COUNT (3) */
        0x75, 0x01,                             /* REPORT_SIZE (1) */
        0xb1, 0x02,                             /* Feature (Data,Var,Abs) */
        0x95, 0x01,                             /* REPORT_COUNT (1) */
        0x75, 0x05,                             /* REPORT_SIZE (5) */
        0x91, 0x01,                             /* Output (Cnst,Var,Abs) */

        0xc0,                           /* END_COLLECTION */
        0xc0,                   /* END_COLLECTION */
};

static __u8 feature_data[] = { 1, 2 };

#define ASSERT_OK(data) ASSERT_FALSE(data)
#define ASSERT_OK_PTR(ptr) ASSERT_NE(NULL, ptr)

#define UHID_LOG(fmt, ...) do { \
        if (SHOW_UHID_DEBUG) \
                TH_LOG(fmt, ##__VA_ARGS__); \
} while (0)

static pthread_mutex_t uhid_started_mtx = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t uhid_started = PTHREAD_COND_INITIALIZER;

static pthread_mutex_t uhid_output_mtx = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t uhid_output_cond = PTHREAD_COND_INITIALIZER;
static unsigned char output_report[10];

/* no need to protect uhid_stopped, only one thread accesses it */
static bool uhid_stopped;

static int uhid_write(struct __test_metadata *_metadata, int fd, const struct uhid_event *ev)
{
        ssize_t ret;

        ret = write(fd, ev, sizeof(*ev));
        if (ret < 0) {
                TH_LOG("Cannot write to uhid: %m");
                return -errno;
        } else if (ret != sizeof(*ev)) {
                TH_LOG("Wrong size written to uhid: %zd != %zu",
                        ret, sizeof(ev));
                return -EFAULT;
        } else {
                return 0;
        }
}

static int uhid_create(struct __test_metadata *_metadata, int fd, int rand_nb,
                       __u16 bus, __u32 vid, __u32 pid, __u8 *rdesc,
                       size_t rdesc_size)
{
        struct uhid_event ev;
        char buf[25];

        sprintf(buf, "test-uhid-device-%d", rand_nb);

        memset(&ev, 0, sizeof(ev));
        ev.type = UHID_CREATE;
        strcpy((char *)ev.u.create.name, buf);
        ev.u.create.rd_data = rdesc;
        ev.u.create.rd_size = rdesc_size;
        ev.u.create.bus = bus;
        ev.u.create.vendor = vid;
        ev.u.create.product = pid;
        ev.u.create.version = 0;
        ev.u.create.country = 0;

        sprintf(buf, "%d", rand_nb);
        strcpy((char *)ev.u.create.phys, buf);

        return uhid_write(_metadata, fd, &ev);
}

static void uhid_destroy(struct __test_metadata *_metadata, struct uhid_device *hid)
{
        struct uhid_event ev;

        memset(&ev, 0, sizeof(ev));
        ev.type = UHID_DESTROY;

        uhid_write(_metadata, hid->uhid_fd, &ev);
}

static int uhid_event(struct __test_metadata *_metadata, int fd)
{
        struct uhid_event ev, answer;
        ssize_t ret;

        memset(&ev, 0, sizeof(ev));
        ret = read(fd, &ev, sizeof(ev));
        if (ret == 0) {
                UHID_LOG("Read HUP on uhid-cdev");
                return -EFAULT;
        } else if (ret < 0) {
                UHID_LOG("Cannot read uhid-cdev: %m");
                return -errno;
        } else if (ret != sizeof(ev)) {
                UHID_LOG("Invalid size read from uhid-dev: %zd != %zu",
                        ret, sizeof(ev));
                return -EFAULT;
        }

        switch (ev.type) {
        case UHID_START:
                pthread_mutex_lock(&uhid_started_mtx);
                pthread_cond_signal(&uhid_started);
                pthread_mutex_unlock(&uhid_started_mtx);

                UHID_LOG("UHID_START from uhid-dev");
                break;
        case UHID_STOP:
                uhid_stopped = true;

                UHID_LOG("UHID_STOP from uhid-dev");
                break;
        case UHID_OPEN:
                UHID_LOG("UHID_OPEN from uhid-dev");
                break;
        case UHID_CLOSE:
                UHID_LOG("UHID_CLOSE from uhid-dev");
                break;
        case UHID_OUTPUT:
                UHID_LOG("UHID_OUTPUT from uhid-dev");

                pthread_mutex_lock(&uhid_output_mtx);
                memcpy(output_report,
                       ev.u.output.data,
                       min(ev.u.output.size, sizeof(output_report)));
                pthread_cond_signal(&uhid_output_cond);
                pthread_mutex_unlock(&uhid_output_mtx);
                break;
        case UHID_GET_REPORT:
                UHID_LOG("UHID_GET_REPORT from uhid-dev");

                answer.type = UHID_GET_REPORT_REPLY;
                answer.u.get_report_reply.id = ev.u.get_report.id;
                answer.u.get_report_reply.err = ev.u.get_report.rnum == 1 ? 0 : -EIO;
                answer.u.get_report_reply.size = sizeof(feature_data);
                memcpy(answer.u.get_report_reply.data, feature_data, sizeof(feature_data));

                uhid_write(_metadata, fd, &answer);

                break;
        case UHID_SET_REPORT:
                UHID_LOG("UHID_SET_REPORT from uhid-dev");

                answer.type = UHID_SET_REPORT_REPLY;
                answer.u.set_report_reply.id = ev.u.set_report.id;
                answer.u.set_report_reply.err = 0; /* success */

                uhid_write(_metadata, fd, &answer);
                break;
        default:
                TH_LOG("Invalid event from uhid-dev: %u", ev.type);
        }

        return 0;
}

struct uhid_thread_args {
        int fd;
        struct __test_metadata *_metadata;
};
static void *uhid_read_events_thread(void *arg)
{
        struct uhid_thread_args *args = (struct uhid_thread_args *)arg;
        struct __test_metadata *_metadata = args->_metadata;
        struct pollfd pfds[1];
        int fd = args->fd;
        int ret = 0;

        pfds[0].fd = fd;
        pfds[0].events = POLLIN;

        uhid_stopped = false;

        while (!uhid_stopped) {
                ret = poll(pfds, 1, 100);
                if (ret < 0) {
                        TH_LOG("Cannot poll for fds: %m");
                        break;
                }
                if (pfds[0].revents & POLLIN) {
                        ret = uhid_event(_metadata, fd);
                        if (ret)
                                break;
                }
        }

        return (void *)(long)ret;
}

static int uhid_start_listener(struct __test_metadata *_metadata, pthread_t *tid, int uhid_fd)
{
        struct uhid_thread_args args = {
                .fd = uhid_fd,
                ._metadata = _metadata,
        };
        int err;

        pthread_mutex_lock(&uhid_started_mtx);
        err = pthread_create(tid, NULL, uhid_read_events_thread, (void *)&args);
        ASSERT_EQ(0, err) {
                TH_LOG("Could not start the uhid thread: %d", err);
                pthread_mutex_unlock(&uhid_started_mtx);
                close(uhid_fd);
                return -EIO;
        }
        pthread_cond_wait(&uhid_started, &uhid_started_mtx);
        pthread_mutex_unlock(&uhid_started_mtx);

        return 0;
}

static int uhid_send_event(struct __test_metadata *_metadata, struct uhid_device *hid,
                           __u8 *buf, size_t size)
{
        struct uhid_event ev;

        if (size > sizeof(ev.u.input.data))
                return -E2BIG;

        memset(&ev, 0, sizeof(ev));
        ev.type = UHID_INPUT2;
        ev.u.input2.size = size;

        memcpy(ev.u.input2.data, buf, size);

        return uhid_write(_metadata, hid->uhid_fd, &ev);
}

static bool match_sysfs_device(struct uhid_device *hid, const char *workdir, struct dirent *dir)
{
        char target[20] = "";
        char phys[512];
        char uevent[1024];
        char temp[512];
        int fd, nread;
        bool found = false;

        snprintf(target, sizeof(target), "%04X:%04X:%04X.*", hid->bus, hid->vid, hid->pid);

        if (fnmatch(target, dir->d_name, 0))
                return false;

        /* we found the correct VID/PID, now check for phys */
        sprintf(uevent, "%s/%s/uevent", workdir, dir->d_name);

        fd = open(uevent, O_RDONLY | O_NONBLOCK);
        if (fd < 0)
                return false;

        sprintf(phys, "PHYS=%d", hid->dev_id);

        nread = read(fd, temp, ARRAY_SIZE(temp));
        if (nread > 0 && (strstr(temp, phys)) != NULL)
                found = true;

        close(fd);

        return found;
}

static int get_hid_id(struct uhid_device *hid)
{
        const char *workdir = "/sys/devices/virtual/misc/uhid";
        const char *str_id;
        DIR *d;
        struct dirent *dir;
        int found = -1, attempts = 3;

        /* it would be nice to be able to use nftw, but the no_alu32 target doesn't support it */

        while (found < 0 && attempts > 0) {
                attempts--;
                d = opendir(workdir);
                if (d) {
                        while ((dir = readdir(d)) != NULL) {
                                if (!match_sysfs_device(hid, workdir, dir))
                                        continue;

                                str_id = dir->d_name + sizeof("0000:0000:0000.");
                                found = (int)strtol(str_id, NULL, 16);

                                break;
                        }
                        closedir(d);
                }
                if (found < 0)
                        usleep(100000);
        }

        return found;
}

static int get_hidraw(struct uhid_device *hid)
{
        const char *workdir = "/sys/devices/virtual/misc/uhid";
        char sysfs[1024];
        DIR *d, *subd;
        struct dirent *dir, *subdir;
        int i, found = -1;

        /* retry 5 times in case the system is loaded */
        for (i = 5; i > 0; i--) {
                usleep(10);
                d = opendir(workdir);

                if (!d)
                        continue;

                while ((dir = readdir(d)) != NULL) {
                        if (!match_sysfs_device(hid, workdir, dir))
                                continue;

                        sprintf(sysfs, "%s/%s/hidraw", workdir, dir->d_name);

                        subd = opendir(sysfs);
                        if (!subd)
                                continue;

                        while ((subdir = readdir(subd)) != NULL) {
                                if (fnmatch("hidraw*", subdir->d_name, 0))
                                        continue;

                                found = atoi(subdir->d_name + strlen("hidraw"));
                        }

                        closedir(subd);

                        if (found > 0)
                                break;
                }
                closedir(d);
        }

        return found;
}

static int open_hidraw(struct uhid_device *hid)
{
        int hidraw_number;
        char hidraw_path[64] = { 0 };

        hidraw_number = get_hidraw(hid);
        if (hidraw_number < 0)
                return hidraw_number;

        /* open hidraw node to check the other side of the pipe */
        sprintf(hidraw_path, "/dev/hidraw%d", hidraw_number);
        return open(hidraw_path, O_RDWR | O_NONBLOCK);
}

static int setup_uhid(struct __test_metadata *_metadata, struct uhid_device *hid,
                      __u16 bus, __u32 vid, __u32 pid, const __u8 *rdesc, size_t rdesc_size)
{
        const char *path = "/dev/uhid";
        time_t t;
        int ret;

        /* initialize random number generator */
        srand((unsigned int)time(&t));

        hid->dev_id = rand() % 1024;
        hid->bus = bus;
        hid->vid = vid;
        hid->pid = pid;

        hid->uhid_fd = open(path, O_RDWR | O_CLOEXEC);
        ASSERT_GE(hid->uhid_fd, 0) TH_LOG("open uhid-cdev failed; %d", hid->uhid_fd);

        ret = uhid_create(_metadata, hid->uhid_fd, hid->dev_id, bus, vid, pid,
                          (__u8 *)rdesc, rdesc_size);
        ASSERT_EQ(0, ret) {
                TH_LOG("create uhid device failed: %d", ret);
                close(hid->uhid_fd);
                return ret;
        }

        /* locate the uevent file of the created device */
        hid->hid_id = get_hid_id(hid);
        ASSERT_GT(hid->hid_id, 0)
                TH_LOG("Could not locate uhid device id: %d", hid->hid_id);

        ret = uhid_start_listener(_metadata, &hid->tid, hid->uhid_fd);
        ASSERT_EQ(0, ret) {
                TH_LOG("could not start udev listener: %d", ret);
                close(hid->uhid_fd);
                return ret;
        }

        return 0;
}