/*
 * Copyright (c) 2011, Max Filippov, Open Source and Linux Lab.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Open Source and Linux Lab nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <stddef.h>
#include "cpu.h"
#include "helper.h"
#include "qemu-log.h"

enum {
    TARGET_SYS_exit = 1,
    TARGET_SYS_read = 3,
    TARGET_SYS_write = 4,
    TARGET_SYS_open = 5,
    TARGET_SYS_close = 6,
    TARGET_SYS_lseek = 19,
    TARGET_SYS_select_one = 29,

    TARGET_SYS_argc = 1000,
    TARGET_SYS_argv_sz = 1001,
    TARGET_SYS_argv = 1002,
    TARGET_SYS_memset = 1004,
};

enum {
    SELECT_ONE_READ   = 1,
    SELECT_ONE_WRITE  = 2,
    SELECT_ONE_EXCEPT = 3,
};

void HELPER(simcall)(CPUXtensaState *env)
{
    uint32_t *regs = env->regs;

    switch (regs[2]) {
    case TARGET_SYS_exit:
        qemu_log("exit(%d) simcall\n", regs[3]);
        exit(regs[3]);
        break;

    case TARGET_SYS_read:
    case TARGET_SYS_write:
        {
            bool is_write = regs[2] == TARGET_SYS_write;
            uint32_t fd = regs[3];
            uint32_t vaddr = regs[4];
            uint32_t len = regs[5];

            while (len > 0) {
                target_phys_addr_t paddr =
                    cpu_get_phys_page_debug(env, vaddr);
                uint32_t page_left =
                    TARGET_PAGE_SIZE - (vaddr & (TARGET_PAGE_SIZE - 1));
                uint32_t io_sz = page_left < len ? page_left : len;
                target_phys_addr_t sz = io_sz;
                void *buf = cpu_physical_memory_map(paddr, &sz, is_write);

                if (buf) {
                    vaddr += io_sz;
                    len -= io_sz;
                    regs[2] = is_write ?
                        write(fd, buf, io_sz) :
                        read(fd, buf, io_sz);
                    regs[3] = errno;
                    cpu_physical_memory_unmap(buf, sz, is_write, sz);
                    if (regs[2] == -1) {
                        break;
                    }
                } else {
                    regs[2] = -1;
                    regs[3] = EINVAL;
                    break;
                }
            }
        }
        break;

    case TARGET_SYS_open:
        {
            char name[1024];
            int rc;
            int i;

            for (i = 0; i < ARRAY_SIZE(name); ++i) {
                rc = cpu_memory_rw_debug(
                        env, regs[3] + i, (uint8_t *)name + i, 1, 0);
                if (rc != 0 || name[i] == 0) {
                    break;
                }
            }

            if (rc == 0 && i < ARRAY_SIZE(name)) {
                regs[2] = open(name, regs[4], regs[5]);
                regs[3] = errno;
            } else {
                regs[2] = -1;
                regs[3] = EINVAL;
            }
        }
        break;

    case TARGET_SYS_close:
        if (regs[3] < 3) {
            regs[2] = regs[3] = 0;
        } else {
            regs[2] = close(regs[3]);
            regs[3] = errno;
        }
        break;

    case TARGET_SYS_lseek:
        regs[2] = lseek(regs[3], (off_t)(int32_t)regs[4], regs[5]);
        regs[3] = errno;
        break;

    case TARGET_SYS_select_one:
        {
            uint32_t fd = regs[3];
            uint32_t rq = regs[4];
            uint32_t target_tv = regs[5];
            uint32_t target_tvv[2];

            struct timeval tv = {0};
            fd_set fdset;

            FD_ZERO(&fdset);
            FD_SET(fd, &fdset);

            if (target_tv) {
                cpu_memory_rw_debug(env, target_tv,
                        (uint8_t *)target_tvv, sizeof(target_tvv), 0);
                tv.tv_sec = (int32_t)tswap32(target_tvv[0]);
                tv.tv_usec = (int32_t)tswap32(target_tvv[1]);
            }
            regs[2] = select(fd + 1,
                    rq == SELECT_ONE_READ   ? &fdset : NULL,
                    rq == SELECT_ONE_WRITE  ? &fdset : NULL,
                    rq == SELECT_ONE_EXCEPT ? &fdset : NULL,
                    target_tv ? &tv : NULL);
            regs[3] = errno;
        }
        break;

    case TARGET_SYS_argc:
        regs[2] = 1;
        regs[3] = 0;
        break;

    case TARGET_SYS_argv_sz:
        regs[2] = 128;
        regs[3] = 0;
        break;

    case TARGET_SYS_argv:
        {
            struct Argv {
                uint32_t argptr[2];
                char text[120];
            } argv = {
                {0, 0},
                "test"
            };

            argv.argptr[0] = tswap32(regs[3] + offsetof(struct Argv, text));
            cpu_memory_rw_debug(
                    env, regs[3], (uint8_t *)&argv, sizeof(argv), 1);
        }
        break;

    case TARGET_SYS_memset:
        {
            uint32_t base = regs[3];
            uint32_t sz = regs[5];

            while (sz) {
                target_phys_addr_t len = sz;
                void *buf = cpu_physical_memory_map(base, &len, 1);

                if (buf && len) {
                    memset(buf, regs[4], len);
                    cpu_physical_memory_unmap(buf, len, 1, len);
                } else {
                    len = 1;
                }
                base += len;
                sz -= len;
            }
            regs[2] = regs[3];
            regs[3] = 0;
        }
        break;

    default:
        qemu_log("%s(%d): not implemented\n", __func__, regs[2]);
        regs[2] = -1;
        regs[3] = ENOSYS;
        break;
    }
}