/*
 *  m68k/ColdFire Semihosting syscall interface
 *
 *  Copyright (c) 2005-2007 CodeSourcery.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include "qemu/osdep.h"

#include "cpu.h"
#include "exec/gdbstub.h"
#if defined(CONFIG_USER_ONLY)
#include "qemu.h"
#define SEMIHOSTING_HEAP_SIZE (128 * 1024 * 1024)
#else
#include "semihosting/softmmu-uaccess.h"
#include "hw/boards.h"
#endif
#include "qemu/log.h"

#define HOSTED_EXIT  0
#define HOSTED_INIT_SIM 1
#define HOSTED_OPEN 2
#define HOSTED_CLOSE 3
#define HOSTED_READ 4
#define HOSTED_WRITE 5
#define HOSTED_LSEEK 6
#define HOSTED_RENAME 7
#define HOSTED_UNLINK 8
#define HOSTED_STAT 9
#define HOSTED_FSTAT 10
#define HOSTED_GETTIMEOFDAY 11
#define HOSTED_ISATTY 12
#define HOSTED_SYSTEM 13

static int translate_openflags(int flags)
{
    int hf;

    if (flags & GDB_O_WRONLY)
        hf = O_WRONLY;
    else if (flags & GDB_O_RDWR)
        hf = O_RDWR;
    else
        hf = O_RDONLY;

    if (flags & GDB_O_APPEND) hf |= O_APPEND;
    if (flags & GDB_O_CREAT) hf |= O_CREAT;
    if (flags & GDB_O_TRUNC) hf |= O_TRUNC;
    if (flags & GDB_O_EXCL) hf |= O_EXCL;

    return hf;
}

static void translate_stat(CPUM68KState *env, target_ulong addr, struct stat *s)
{
    struct gdb_stat *p;

    p = lock_user(VERIFY_WRITE, addr, sizeof(struct gdb_stat), 0);
    if (!p) {
        /* FIXME - should this return an error code? */
        return;
    }
    p->gdb_st_dev = cpu_to_be32(s->st_dev);
    p->gdb_st_ino = cpu_to_be32(s->st_ino);
    p->gdb_st_mode = cpu_to_be32(s->st_mode);
    p->gdb_st_nlink = cpu_to_be32(s->st_nlink);
    p->gdb_st_uid = cpu_to_be32(s->st_uid);
    p->gdb_st_gid = cpu_to_be32(s->st_gid);
    p->gdb_st_rdev = cpu_to_be32(s->st_rdev);
    p->gdb_st_size = cpu_to_be64(s->st_size);
#ifdef _WIN32
    /* Windows stat is missing some fields.  */
    p->gdb_st_blksize = 0;
    p->gdb_st_blocks = 0;
#else
    p->gdb_st_blksize = cpu_to_be64(s->st_blksize);
    p->gdb_st_blocks = cpu_to_be64(s->st_blocks);
#endif
    p->gdb_st_atime = cpu_to_be32(s->st_atime);
    p->gdb_st_mtime = cpu_to_be32(s->st_mtime);
    p->gdb_st_ctime = cpu_to_be32(s->st_ctime);
    unlock_user(p, addr, sizeof(struct gdb_stat));
}

static void m68k_semi_return_u32(CPUM68KState *env, uint32_t ret, uint32_t err)
{
    target_ulong args = env->dregs[1];
    if (put_user_u32(ret, args) ||
        put_user_u32(err, args + 4)) {
        /*
         * The m68k semihosting ABI does not provide any way to report this
         * error to the guest, so the best we can do is log it in qemu.
         * It is always a guest error not to pass us a valid argument block.
         */
        qemu_log_mask(LOG_GUEST_ERROR, "m68k-semihosting: return value "
                      "discarded because argument block not writable\n");
    }
}

static void m68k_semi_return_u64(CPUM68KState *env, uint64_t ret, uint32_t err)
{
    target_ulong args = env->dregs[1];
    if (put_user_u32(ret >> 32, args) ||
        put_user_u32(ret, args + 4) ||
        put_user_u32(err, args + 8)) {
        /* No way to report this via m68k semihosting ABI; just log it */
        qemu_log_mask(LOG_GUEST_ERROR, "m68k-semihosting: return value "
                      "discarded because argument block not writable\n");
    }
}

static int m68k_semi_is_fseek;

static void m68k_semi_cb(CPUState *cs, target_ulong ret, target_ulong err)
{
    M68kCPU *cpu = M68K_CPU(cs);
    CPUM68KState *env = &cpu->env;

    if (m68k_semi_is_fseek) {
        /*
         * FIXME: We've already lost the high bits of the fseek
         * return value.
         */
        m68k_semi_return_u64(env, ret, err);
        m68k_semi_is_fseek = 0;
    } else {
        m68k_semi_return_u32(env, ret, err);
    }
}

/*
 * Read the input value from the argument block; fail the semihosting
 * call if the memory read fails.
 */
#define GET_ARG(n) do {                                 \
    if (get_user_ual(arg ## n, args + (n) * 4)) {       \
        result = -1;                                    \
        errno = EFAULT;                                 \
        goto failed;                                    \
    }                                                   \
} while (0)

void do_m68k_semihosting(CPUM68KState *env, int nr)
{
    uint32_t args;
    target_ulong arg0, arg1, arg2, arg3;
    void *p;
    void *q;
    uint32_t len;
    uint32_t result;

    args = env->dregs[1];
    switch (nr) {
    case HOSTED_EXIT:
        gdb_exit(env->dregs[0]);
        exit(env->dregs[0]);
    case HOSTED_OPEN:
        GET_ARG(0);
        GET_ARG(1);
        GET_ARG(2);
        GET_ARG(3);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "open,%s,%x,%x", arg0, (int)arg1,
                           arg2, arg3);
            return;
        } else {
            p = lock_user_string(arg0);
            if (!p) {
                /* FIXME - check error code? */
                result = -1;
            } else {
                result = open(p, translate_openflags(arg2), arg3);
                unlock_user(p, arg0, 0);
            }
        }
        break;
    case HOSTED_CLOSE:
        {
            /* Ignore attempts to close stdin/out/err.  */
            GET_ARG(0);
            int fd = arg0;
            if (fd > 2) {
                if (use_gdb_syscalls()) {
                    gdb_do_syscall(m68k_semi_cb, "close,%x", arg0);
                    return;
                } else {
                    result = close(fd);
                }
            } else {
                result = 0;
            }
            break;
        }
    case HOSTED_READ:
        GET_ARG(0);
        GET_ARG(1);
        GET_ARG(2);
        len = arg2;
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "read,%x,%x,%x",
                           arg0, arg1, len);
            return;
        } else {
            p = lock_user(VERIFY_WRITE, arg1, len, 0);
            if (!p) {
                /* FIXME - check error code? */
                result = -1;
            } else {
                result = read(arg0, p, len);
                unlock_user(p, arg1, len);
            }
        }
        break;
    case HOSTED_WRITE:
        GET_ARG(0);
        GET_ARG(1);
        GET_ARG(2);
        len = arg2;
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "write,%x,%x,%x",
                           arg0, arg1, len);
            return;
        } else {
            p = lock_user(VERIFY_READ, arg1, len, 1);
            if (!p) {
                /* FIXME - check error code? */
                result = -1;
            } else {
                result = write(arg0, p, len);
                unlock_user(p, arg0, 0);
            }
        }
        break;
    case HOSTED_LSEEK:
        {
            uint64_t off;
            GET_ARG(0);
            GET_ARG(1);
            GET_ARG(2);
            GET_ARG(3);
            off = (uint32_t)arg2 | ((uint64_t)arg1 << 32);
            if (use_gdb_syscalls()) {
                m68k_semi_is_fseek = 1;
                gdb_do_syscall(m68k_semi_cb, "fseek,%x,%lx,%x",
                               arg0, off, arg3);
            } else {
                off = lseek(arg0, off, arg3);
                m68k_semi_return_u64(env, off, errno);
            }
            return;
        }
    case HOSTED_RENAME:
        GET_ARG(0);
        GET_ARG(1);
        GET_ARG(2);
        GET_ARG(3);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "rename,%s,%s",
                           arg0, (int)arg1, arg2, (int)arg3);
            return;
        } else {
            p = lock_user_string(arg0);
            q = lock_user_string(arg2);
            if (!p || !q) {
                /* FIXME - check error code? */
                result = -1;
            } else {
                result = rename(p, q);
            }
            unlock_user(p, arg0, 0);
            unlock_user(q, arg2, 0);
        }
        break;
    case HOSTED_UNLINK:
        GET_ARG(0);
        GET_ARG(1);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "unlink,%s",
                           arg0, (int)arg1);
            return;
        } else {
            p = lock_user_string(arg0);
            if (!p) {
                /* FIXME - check error code? */
                result = -1;
            } else {
                result = unlink(p);
                unlock_user(p, arg0, 0);
            }
        }
        break;
    case HOSTED_STAT:
        GET_ARG(0);
        GET_ARG(1);
        GET_ARG(2);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "stat,%s,%x",
                           arg0, (int)arg1, arg2);
            return;
        } else {
            struct stat s;
            p = lock_user_string(arg0);
            if (!p) {
                /* FIXME - check error code? */
                result = -1;
            } else {
                result = stat(p, &s);
                unlock_user(p, arg0, 0);
            }
            if (result == 0) {
                translate_stat(env, arg2, &s);
            }
        }
        break;
    case HOSTED_FSTAT:
        GET_ARG(0);
        GET_ARG(1);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "fstat,%x,%x",
                           arg0, arg1);
            return;
        } else {
            struct stat s;
            result = fstat(arg0, &s);
            if (result == 0) {
                translate_stat(env, arg1, &s);
            }
        }
        break;
    case HOSTED_GETTIMEOFDAY:
        GET_ARG(0);
        GET_ARG(1);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "gettimeofday,%x,%x",
                           arg0, arg1);
            return;
        } else {
            struct gdb_timeval *p;
            int64_t rt = g_get_real_time();
            p = lock_user(VERIFY_WRITE, arg0, sizeof(struct gdb_timeval), 0);
            if (!p) {
                /* FIXME - check error code? */
                result = -1;
            } else {
                result = 0;
                p->tv_sec = cpu_to_be32(rt / G_USEC_PER_SEC);
                p->tv_usec = cpu_to_be64(rt % G_USEC_PER_SEC);
                unlock_user(p, arg0, sizeof(struct gdb_timeval));
            }
        }
        break;
    case HOSTED_ISATTY:
        GET_ARG(0);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "isatty,%x", arg0);
            return;
        } else {
            result = isatty(arg0);
        }
        break;
    case HOSTED_SYSTEM:
        GET_ARG(0);
        GET_ARG(1);
        if (use_gdb_syscalls()) {
            gdb_do_syscall(m68k_semi_cb, "system,%s",
                           arg0, (int)arg1);
            return;
        } else {
            p = lock_user_string(arg0);
            if (!p) {
                /* FIXME - check error code? */
                result = -1;
            } else {
                result = system(p);
                unlock_user(p, arg0, 0);
            }
        }
        break;
    case HOSTED_INIT_SIM:
#if defined(CONFIG_USER_ONLY)
        {
        CPUState *cs = env_cpu(env);
        TaskState *ts = cs->opaque;
        /* Allocate the heap using sbrk.  */
        if (!ts->heap_limit) {
            abi_ulong ret;
            uint32_t size;
            uint32_t base;

            base = do_brk(0);
            size = SEMIHOSTING_HEAP_SIZE;
            /* Try a big heap, and reduce the size if that fails.  */
            for (;;) {
                ret = do_brk(base + size);
                if (ret >= (base + size)) {
                    break;
                }
                size >>= 1;
            }
            ts->heap_limit = base + size;
        }
        /*
         * This call may happen before we have writable memory, so return
         * values directly in registers.
         */
        env->dregs[1] = ts->heap_limit;
        env->aregs[7] = ts->stack_base;
        }
#else
        /*
         * FIXME: This is wrong for boards where RAM does not start at
         * address zero.
         */
        env->dregs[1] = current_machine->ram_size;
        env->aregs[7] = current_machine->ram_size;
#endif
        return;
    default:
        cpu_abort(env_cpu(env), "Unsupported semihosting syscall %d\n", nr);
        result = 0;
    }
failed:
    m68k_semi_return_u32(env, result, errno);
}