// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * ffs-test.c -- user mode filesystem api for usb composite function
 *
 * Copyright (C) 2010 Samsung Electronics
 *                    Author: Michal Nazarewicz <mina86@mina86.com>
 */

/* $(CROSS_COMPILE)cc -Wall -Wextra -g -o ffs-test ffs-test.c -lpthread */


#define _DEFAULT_SOURCE /* for endian.h */

#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <tools/le_byteshift.h>

#include "../../include/uapi/linux/usb/functionfs.h"


/******************** Little Endian Handling ********************************/

/*
 * cpu_to_le16/32 are used when initializing structures, a context where a
 * function call is not allowed. To solve this, we code cpu_to_le16/32 in a way
 * that allows them to be used when initializing structures.
 */

#if __BYTE_ORDER == __LITTLE_ENDIAN
#define cpu_to_le16(x)  (x)
#define cpu_to_le32(x)  (x)
#else
#define cpu_to_le16(x)  ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8))
#define cpu_to_le32(x)  \
        ((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >>  8) | \
        (((x) & 0x0000ff00u) <<  8) | (((x) & 0x000000ffu) << 24))
#endif

#define le32_to_cpu(x)  le32toh(x)
#define le16_to_cpu(x)  le16toh(x)

/******************** Messages and Errors ***********************************/

static const char argv0[] = "ffs-test";

static unsigned verbosity = 7;

static void _msg(unsigned level, const char *fmt, ...)
{
        if (level < 2)
                level = 2;
        else if (level > 7)
                level = 7;

        if (level <= verbosity) {
                static const char levels[8][6] = {
                        [2] = "crit:",
                        [3] = "err: ",
                        [4] = "warn:",
                        [5] = "note:",
                        [6] = "info:",
                        [7] = "dbg: "
                };

                int _errno = errno;
                va_list ap;

                fprintf(stderr, "%s: %s ", argv0, levels[level]);
                va_start(ap, fmt);
                vfprintf(stderr, fmt, ap);
                va_end(ap);

                if (fmt[strlen(fmt) - 1] != '\n') {
                        char buffer[128];
                        strerror_r(_errno, buffer, sizeof buffer);
                        fprintf(stderr, ": (-%d) %s\n", _errno, buffer);
                }

                fflush(stderr);
        }
}

#define die(...)  (_msg(2, __VA_ARGS__), exit(1))
#define err(...)   _msg(3, __VA_ARGS__)
#define warn(...)  _msg(4, __VA_ARGS__)
#define note(...)  _msg(5, __VA_ARGS__)
#define info(...)  _msg(6, __VA_ARGS__)
#define debug(...) _msg(7, __VA_ARGS__)

#define die_on(cond, ...) do { \
        if (cond) \
                die(__VA_ARGS__); \
        } while (0)


/******************** Descriptors and Strings *******************************/

static const struct {
        struct usb_functionfs_descs_head_v2 header;
        __le32 fs_count;
        __le32 hs_count;
        __le32 ss_count;
        struct {
                struct usb_interface_descriptor intf;
                struct usb_endpoint_descriptor_no_audio sink;
                struct usb_endpoint_descriptor_no_audio source;
        } __attribute__((packed)) fs_descs, hs_descs;
        struct {
                struct usb_interface_descriptor intf;
                struct usb_endpoint_descriptor_no_audio sink;
                struct usb_ss_ep_comp_descriptor sink_comp;
                struct usb_endpoint_descriptor_no_audio source;
                struct usb_ss_ep_comp_descriptor source_comp;
        } ss_descs;
} __attribute__((packed)) descriptors = {
        .header = {
                .magic = cpu_to_le32(FUNCTIONFS_DESCRIPTORS_MAGIC_V2),
                .flags = cpu_to_le32(FUNCTIONFS_HAS_FS_DESC |
                                     FUNCTIONFS_HAS_HS_DESC |
                                     FUNCTIONFS_HAS_SS_DESC),
                .length = cpu_to_le32(sizeof descriptors),
        },
        .fs_count = cpu_to_le32(3),
        .fs_descs = {
                .intf = {
                        .bLength = sizeof descriptors.fs_descs.intf,
                        .bDescriptorType = USB_DT_INTERFACE,
                        .bNumEndpoints = 2,
                        .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
                        .iInterface = 1,
                },
                .sink = {
                        .bLength = sizeof descriptors.fs_descs.sink,
                        .bDescriptorType = USB_DT_ENDPOINT,
                        .bEndpointAddress = 1 | USB_DIR_IN,
                        .bmAttributes = USB_ENDPOINT_XFER_BULK,
                        /* .wMaxPacketSize = autoconfiguration (kernel) */
                },
                .source = {
                        .bLength = sizeof descriptors.fs_descs.source,
                        .bDescriptorType = USB_DT_ENDPOINT,
                        .bEndpointAddress = 2 | USB_DIR_OUT,
                        .bmAttributes = USB_ENDPOINT_XFER_BULK,
                        /* .wMaxPacketSize = autoconfiguration (kernel) */
                },
        },
        .hs_count = cpu_to_le32(3),
        .hs_descs = {
                .intf = {
                        .bLength = sizeof descriptors.fs_descs.intf,
                        .bDescriptorType = USB_DT_INTERFACE,
                        .bNumEndpoints = 2,
                        .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
                        .iInterface = 1,
                },
                .sink = {
                        .bLength = sizeof descriptors.hs_descs.sink,
                        .bDescriptorType = USB_DT_ENDPOINT,
                        .bEndpointAddress = 1 | USB_DIR_IN,
                        .bmAttributes = USB_ENDPOINT_XFER_BULK,
                        .wMaxPacketSize = cpu_to_le16(512),
                },
                .source = {
                        .bLength = sizeof descriptors.hs_descs.source,
                        .bDescriptorType = USB_DT_ENDPOINT,
                        .bEndpointAddress = 2 | USB_DIR_OUT,
                        .bmAttributes = USB_ENDPOINT_XFER_BULK,
                        .wMaxPacketSize = cpu_to_le16(512),
                        .bInterval = 1, /* NAK every 1 uframe */
                },
        },
        .ss_count = cpu_to_le32(5),
        .ss_descs = {
                .intf = {
                        .bLength = sizeof descriptors.fs_descs.intf,
                        .bDescriptorType = USB_DT_INTERFACE,
                        .bNumEndpoints = 2,
                        .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
                        .iInterface = 1,
                },
                .sink = {
                        .bLength = sizeof descriptors.hs_descs.sink,
                        .bDescriptorType = USB_DT_ENDPOINT,
                        .bEndpointAddress = 1 | USB_DIR_IN,
                        .bmAttributes = USB_ENDPOINT_XFER_BULK,
                        .wMaxPacketSize = cpu_to_le16(1024),
                },
                .sink_comp = {
                        .bLength = USB_DT_SS_EP_COMP_SIZE,
                        .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
                        .bMaxBurst = 0,
                        .bmAttributes = 0,
                        .wBytesPerInterval = 0,
                },
                .source = {
                        .bLength = sizeof descriptors.hs_descs.source,
                        .bDescriptorType = USB_DT_ENDPOINT,
                        .bEndpointAddress = 2 | USB_DIR_OUT,
                        .bmAttributes = USB_ENDPOINT_XFER_BULK,
                        .wMaxPacketSize = cpu_to_le16(1024),
                        .bInterval = 1, /* NAK every 1 uframe */
                },
                .source_comp = {
                        .bLength = USB_DT_SS_EP_COMP_SIZE,
                        .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
                        .bMaxBurst = 0,
                        .bmAttributes = 0,
                        .wBytesPerInterval = 0,
                },
        },
};

static size_t descs_to_legacy(void **legacy, const void *descriptors_v2)
{
        const unsigned char *descs_end, *descs_start;
        __u32 length, fs_count = 0, hs_count = 0, count;

        /* Read v2 header */
        {
                const struct {
                        const struct usb_functionfs_descs_head_v2 header;
                        const __le32 counts[];
                } __attribute__((packed)) *const in = descriptors_v2;
                const __le32 *counts = in->counts;
                __u32 flags;

                if (le32_to_cpu(in->header.magic) !=
                    FUNCTIONFS_DESCRIPTORS_MAGIC_V2)
                        return 0;
                length = le32_to_cpu(in->header.length);
                if (length <= sizeof in->header)
                        return 0;
                length -= sizeof in->header;
                flags = le32_to_cpu(in->header.flags);
                if (flags & ~(FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC |
                              FUNCTIONFS_HAS_SS_DESC))
                        return 0;

#define GET_NEXT_COUNT_IF_FLAG(ret, flg) do {           \
                        if (!(flags & (flg)))           \
                                break;                  \
                        if (length < 4)                 \
                                return 0;               \
                        ret = le32_to_cpu(*counts);     \
                        length -= 4;                    \
                        ++counts;                       \
                } while (0)

                GET_NEXT_COUNT_IF_FLAG(fs_count, FUNCTIONFS_HAS_FS_DESC);
                GET_NEXT_COUNT_IF_FLAG(hs_count, FUNCTIONFS_HAS_HS_DESC);
                GET_NEXT_COUNT_IF_FLAG(count, FUNCTIONFS_HAS_SS_DESC);

                count = fs_count + hs_count;
                if (!count)
                        return 0;
                descs_start = (const void *)counts;

#undef GET_NEXT_COUNT_IF_FLAG
        }

        /*
         * Find the end of FS and HS USB descriptors.  SS descriptors
         * are ignored since legacy format does not support them.
         */
        descs_end = descs_start;
        do {
                if (length < *descs_end)
                        return 0;
                length -= *descs_end;
                descs_end += *descs_end;
        } while (--count);

        /* Allocate legacy descriptors and copy the data. */
        {
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
                struct {
                        struct usb_functionfs_descs_head header;
                        __u8 descriptors[];
                } __attribute__((packed)) *out;
#pragma GCC diagnostic pop

                length = sizeof out->header + (descs_end - descs_start);
                out = malloc(length);
                out->header.magic = cpu_to_le32(FUNCTIONFS_DESCRIPTORS_MAGIC);
                out->header.length = cpu_to_le32(length);
                out->header.fs_count = cpu_to_le32(fs_count);
                out->header.hs_count = cpu_to_le32(hs_count);
                memcpy(out->descriptors, descs_start, descs_end - descs_start);
                *legacy = out;
        }

        return length;
}


#define STR_INTERFACE_ "Source/Sink"

static const struct {
        struct usb_functionfs_strings_head header;
        struct {
                __le16 code;
                const char str1[sizeof STR_INTERFACE_];
        } __attribute__((packed)) lang0;
} __attribute__((packed)) strings = {
        .header = {
                .magic = cpu_to_le32(FUNCTIONFS_STRINGS_MAGIC),
                .length = cpu_to_le32(sizeof strings),
                .str_count = cpu_to_le32(1),
                .lang_count = cpu_to_le32(1),
        },
        .lang0 = {
                cpu_to_le16(0x0409), /* en-us */
                STR_INTERFACE_,
        },
};

#define STR_INTERFACE strings.lang0.str1


/******************** Files and Threads Handling ****************************/

struct thread;

static ssize_t read_wrap(struct thread *t, void *buf, size_t nbytes);
static ssize_t write_wrap(struct thread *t, const void *buf, size_t nbytes);
static ssize_t ep0_consume(struct thread *t, const void *buf, size_t nbytes);
static ssize_t fill_in_buf(struct thread *t, void *buf, size_t nbytes);
static ssize_t empty_out_buf(struct thread *t, const void *buf, size_t nbytes);


static struct thread {
        const char *const filename;
        size_t buf_size;

        ssize_t (*in)(struct thread *, void *, size_t);
        const char *const in_name;

        ssize_t (*out)(struct thread *, const void *, size_t);
        const char *const out_name;

        int fd;
        pthread_t id;
        void *buf;
        ssize_t status;
} threads[] = {
        {
                "ep0", 4 * sizeof(struct usb_functionfs_event),
                read_wrap, NULL,
                ep0_consume, "<consume>",
                0, 0, NULL, 0
        },
        {
                "ep1", 8 * 1024,
                fill_in_buf, "<in>",
                write_wrap, NULL,
                0, 0, NULL, 0
        },
        {
                "ep2", 8 * 1024,
                read_wrap, NULL,
                empty_out_buf, "<out>",
                0, 0, NULL, 0
        },
};


static void init_thread(struct thread *t)
{
        t->buf = malloc(t->buf_size);
        die_on(!t->buf, "malloc");

        t->fd = open(t->filename, O_RDWR);
        die_on(t->fd < 0, "%s", t->filename);
}

static void cleanup_thread(void *arg)
{
        struct thread *t = arg;
        int ret, fd;

        fd = t->fd;
        if (t->fd < 0)
                return;
        t->fd = -1;

        /* test the FIFO ioctls (non-ep0 code paths) */
        if (t != threads) {
                ret = ioctl(fd, FUNCTIONFS_FIFO_STATUS);
                if (ret < 0) {
                        /* ENODEV reported after disconnect */
                        if (errno != ENODEV)
                                err("%s: get fifo status", t->filename);
                } else if (ret) {
                        warn("%s: unclaimed = %d\n", t->filename, ret);
                        if (ioctl(fd, FUNCTIONFS_FIFO_FLUSH) < 0)
                                err("%s: fifo flush", t->filename);
                }
        }

        if (close(fd) < 0)
                err("%s: close", t->filename);

        free(t->buf);
        t->buf = NULL;
}

static void *start_thread_helper(void *arg)
{
        const char *name, *op, *in_name, *out_name;
        struct thread *t = arg;
        ssize_t ret;

        info("%s: starts\n", t->filename);
        in_name = t->in_name ? t->in_name : t->filename;
        out_name = t->out_name ? t->out_name : t->filename;

        pthread_cleanup_push(cleanup_thread, arg);

        for (;;) {
                pthread_testcancel();

                ret = t->in(t, t->buf, t->buf_size);
                if (ret > 0) {
                        ret = t->out(t, t->buf, ret);
                        name = out_name;
                        op = "write";
                } else {
                        name = in_name;
                        op = "read";
                }

                if (ret > 0) {
                        /* nop */
                } else if (!ret) {
                        debug("%s: %s: EOF", name, op);
                        break;
                } else if (errno == EINTR || errno == EAGAIN) {
                        debug("%s: %s", name, op);
                } else {
                        warn("%s: %s", name, op);
                        break;
                }
        }

        pthread_cleanup_pop(1);

        t->status = ret;
        info("%s: ends\n", t->filename);
        return NULL;
}

static void start_thread(struct thread *t)
{
        debug("%s: starting\n", t->filename);

        die_on(pthread_create(&t->id, NULL, start_thread_helper, t) < 0,
               "pthread_create(%s)", t->filename);
}

static void join_thread(struct thread *t)
{
        int ret = pthread_join(t->id, NULL);

        if (ret < 0)
                err("%s: joining thread", t->filename);
        else
                debug("%s: joined\n", t->filename);
}


static ssize_t read_wrap(struct thread *t, void *buf, size_t nbytes)
{
        return read(t->fd, buf, nbytes);
}

static ssize_t write_wrap(struct thread *t, const void *buf, size_t nbytes)
{
        return write(t->fd, buf, nbytes);
}


/******************** Empty/Fill buffer routines ****************************/

/* 0 -- stream of zeros, 1 -- i % 63, 2 -- pipe */
enum pattern { PAT_ZERO, PAT_SEQ, PAT_PIPE };
static enum pattern pattern;

static ssize_t
fill_in_buf(struct thread *ignore, void *buf, size_t nbytes)
{
        size_t i;
        __u8 *p;

        (void)ignore;

        switch (pattern) {
        case PAT_ZERO:
                memset(buf, 0, nbytes);
                break;

        case PAT_SEQ:
                for (p = buf, i = 0; i < nbytes; ++i, ++p)
                        *p = i % 63;
                break;

        case PAT_PIPE:
                return fread(buf, 1, nbytes, stdin);
        }

        return nbytes;
}

static ssize_t
empty_out_buf(struct thread *ignore, const void *buf, size_t nbytes)
{
        const __u8 *p;
        __u8 expected;
        ssize_t ret;
        size_t len;

        (void)ignore;

        switch (pattern) {
        case PAT_ZERO:
                expected = 0;
                for (p = buf, len = 0; len < nbytes; ++p, ++len)
                        if (*p)
                                goto invalid;
                break;

        case PAT_SEQ:
                for (p = buf, len = 0; len < nbytes; ++p, ++len)
                        if (*p != len % 63) {
                                expected = len % 63;
                                goto invalid;
                        }
                break;

        case PAT_PIPE:
                ret = fwrite(buf, nbytes, 1, stdout);
                if (ret > 0)
                        fflush(stdout);
                break;

invalid:
                err("bad OUT byte %zd, expected %02x got %02x\n",
                    len, expected, *p);
                for (p = buf, len = 0; len < nbytes; ++p, ++len) {
                        if (0 == (len % 32))
                                fprintf(stderr, "%4zd:", len);
                        fprintf(stderr, " %02x", *p);
                        if (31 == (len % 32))
                                fprintf(stderr, "\n");
                }
                fflush(stderr);
                errno = EILSEQ;
                return -1;
        }

        return len;
}


/******************** Endpoints routines ************************************/

static void handle_setup(const struct usb_ctrlrequest *setup)
{
        printf("bRequestType = %d\n", setup->bRequestType);
        printf("bRequest     = %d\n", setup->bRequest);
        printf("wValue       = %d\n", le16_to_cpu(setup->wValue));
        printf("wIndex       = %d\n", le16_to_cpu(setup->wIndex));
        printf("wLength      = %d\n", le16_to_cpu(setup->wLength));
}

static ssize_t
ep0_consume(struct thread *ignore, const void *buf, size_t nbytes)
{
        static const char *const names[] = {
                [FUNCTIONFS_BIND] = "BIND",
                [FUNCTIONFS_UNBIND] = "UNBIND",
                [FUNCTIONFS_ENABLE] = "ENABLE",
                [FUNCTIONFS_DISABLE] = "DISABLE",
                [FUNCTIONFS_SETUP] = "SETUP",
                [FUNCTIONFS_SUSPEND] = "SUSPEND",
                [FUNCTIONFS_RESUME] = "RESUME",
        };

        const struct usb_functionfs_event *event = buf;
        size_t n;

        (void)ignore;

        for (n = nbytes / sizeof *event; n; --n, ++event)
                switch (event->type) {
                case FUNCTIONFS_BIND:
                case FUNCTIONFS_UNBIND:
                case FUNCTIONFS_ENABLE:
                case FUNCTIONFS_DISABLE:
                case FUNCTIONFS_SETUP:
                case FUNCTIONFS_SUSPEND:
                case FUNCTIONFS_RESUME:
                        printf("Event %s\n", names[event->type]);
                        if (event->type == FUNCTIONFS_SETUP)
                                handle_setup(&event->u.setup);
                        break;

                default:
                        printf("Event %03u (unknown)\n", event->type);
                }

        return nbytes;
}

static void ep0_init(struct thread *t, bool legacy_descriptors)
{
        void *legacy;
        ssize_t ret;
        size_t len;

        if (legacy_descriptors) {
                info("%s: writing descriptors\n", t->filename);
                goto legacy;
        }

        info("%s: writing descriptors (in v2 format)\n", t->filename);
        ret = write(t->fd, &descriptors, sizeof descriptors);

        if (ret < 0 && errno == EINVAL) {
                warn("%s: new format rejected, trying legacy\n", t->filename);
legacy:
                len = descs_to_legacy(&legacy, &descriptors);
                if (len) {
                        ret = write(t->fd, legacy, len);
                        free(legacy);
                }
        }
        die_on(ret < 0, "%s: write: descriptors", t->filename);

        info("%s: writing strings\n", t->filename);
        ret = write(t->fd, &strings, sizeof strings);
        die_on(ret < 0, "%s: write: strings", t->filename);
}


/******************** Main **************************************************/

int main(int argc, char **argv)
{
        bool legacy_descriptors;
        unsigned i;

        legacy_descriptors = argc > 2 && !strcmp(argv[1], "-l");

        init_thread(threads);
        ep0_init(threads, legacy_descriptors);

        for (i = 1; i < sizeof threads / sizeof *threads; ++i)
                init_thread(threads + i);

        for (i = 1; i < sizeof threads / sizeof *threads; ++i)
                start_thread(threads + i);

        start_thread_helper(threads);

        for (i = 1; i < sizeof threads / sizeof *threads; ++i)
                join_thread(threads + i);

        return 0;
}