Archipelago » qemu

#include "qemu-common.h"

#include "qemu/iov.h"

#include "qemu/sockets.h"

#include "block/coroutine.h"

#include "migration/migration.h"

#include "migration/qemu-file.h"

#define IO_BUF_SIZE 32768

#define MAX_IOV_SIZE MIN(IOV_MAX, 64)

struct QEMUFile {

    const QEMUFileOps *ops;

    void *opaque;

    int64_t bytes_xfer;

    int64_t xfer_limit;

    int64_t pos; /* start of buffer when writing, end of buffer

                    when reading */

    int buf_index;

    int buf_size; /* 0 when writing */

    uint8_t buf[IO_BUF_SIZE];

    struct iovec iov[MAX_IOV_SIZE];

    unsigned int iovcnt;

    int last_error;

};

typedef struct QEMUFileStdio {

    FILE *stdio_file;

    QEMUFile *file;

} QEMUFileStdio;

typedef struct QEMUFileSocket {

    int fd;

    QEMUFile *file;

} QEMUFileSocket;

static ssize_t socket_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,

                                    int64_t pos)

{

    QEMUFileSocket *s = opaque;

    ssize_t len;

    ssize_t size = iov_size(iov, iovcnt);

    len = iov_send(s->fd, iov, iovcnt, 0, size);

    if (len < size) {

        len = -socket_error();

    }

    return len;

}

static int socket_get_fd(void *opaque)

{

    QEMUFileSocket *s = opaque;

    return s->fd;

}

static int socket_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)

{

    QEMUFileSocket *s = opaque;

    ssize_t len;

    for (;;) {

        len = qemu_recv(s->fd, buf, size, 0);

        if (len != -1) {

            break;

        }

        if (socket_error() == EAGAIN) {

            yield_until_fd_readable(s->fd);

        } else if (socket_error() != EINTR) {

            break;

        }

    }

    if (len == -1) {

        len = -socket_error();

    }

    return len;

}

static int socket_close(void *opaque)

{

    QEMUFileSocket *s = opaque;

    closesocket(s->fd);

    g_free(s);

    return 0;

}

static int stdio_get_fd(void *opaque)

{

    QEMUFileStdio *s = opaque;

    return fileno(s->stdio_file);

}

static int stdio_put_buffer(void *opaque, const uint8_t *buf, int64_t pos,

                            int size)

{

    QEMUFileStdio *s = opaque;

    return fwrite(buf, 1, size, s->stdio_file);

}

static int stdio_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)

{

    QEMUFileStdio *s = opaque;

    FILE *fp = s->stdio_file;

    int bytes;

    for (;;) {

        clearerr(fp);

        bytes = fread(buf, 1, size, fp);

        if (bytes != 0 || !ferror(fp)) {

            break;

        }

        if (errno == EAGAIN) {

            yield_until_fd_readable(fileno(fp));

        } else if (errno != EINTR) {

            break;

        }

    }

    return bytes;

}

static int stdio_pclose(void *opaque)

{

    QEMUFileStdio *s = opaque;

    int ret;

    ret = pclose(s->stdio_file);

    if (ret == -1) {

        ret = -errno;

    } else if (!WIFEXITED(ret) || WEXITSTATUS(ret) != 0) {

        /* close succeeded, but non-zero exit code: */

        ret = -EIO; /* fake errno value */

    }

    g_free(s);

    return ret;

}

static int stdio_fclose(void *opaque)

{

    QEMUFileStdio *s = opaque;

    int ret = 0;

    if (s->file->ops->put_buffer || s->file->ops->writev_buffer) {

        int fd = fileno(s->stdio_file);

        struct stat st;

        ret = fstat(fd, &st);

        if (ret == 0 && S_ISREG(st.st_mode)) {

            /*

             * If the file handle is a regular file make sure the

             * data is flushed to disk before signaling success.

             */

            ret = fsync(fd);

            if (ret != 0) {

                ret = -errno;

                return ret;

            }

        }

    }

    if (fclose(s->stdio_file) == EOF) {

        ret = -errno;

    }

    g_free(s);

    return ret;

}

static const QEMUFileOps stdio_pipe_read_ops = {

    .get_fd =     stdio_get_fd,

    .get_buffer = stdio_get_buffer,

    .close =      stdio_pclose

};

static const QEMUFileOps stdio_pipe_write_ops = {

    .get_fd =     stdio_get_fd,

    .put_buffer = stdio_put_buffer,

    .close =      stdio_pclose

};

QEMUFile *qemu_popen_cmd(const char *command, const char *mode)

{

    FILE *stdio_file;

    QEMUFileStdio *s;

    if (mode == NULL || (mode[0] != 'r' && mode[0] != 'w') || mode[1] != 0) {

        fprintf(stderr, "qemu_popen: Argument validity check failed\n");

        return NULL;

    }

    stdio_file = popen(command, mode);

    if (stdio_file == NULL) {

        return NULL;

    }

    s = g_malloc0(sizeof(QEMUFileStdio));

    s->stdio_file = stdio_file;

    if (mode[0] == 'r') {

        s->file = qemu_fopen_ops(s, &stdio_pipe_read_ops);

    } else {

        s->file = qemu_fopen_ops(s, &stdio_pipe_write_ops);

    }

    return s->file;

}

static const QEMUFileOps stdio_file_read_ops = {

    .get_fd =     stdio_get_fd,

    .get_buffer = stdio_get_buffer,

    .close =      stdio_fclose

};

static const QEMUFileOps stdio_file_write_ops = {

    .get_fd =     stdio_get_fd,

    .put_buffer = stdio_put_buffer,

    .close =      stdio_fclose

};

static ssize_t unix_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,

                                  int64_t pos)

{

    QEMUFileSocket *s = opaque;

    ssize_t len, offset;

    ssize_t size = iov_size(iov, iovcnt);

    ssize_t total = 0;

    assert(iovcnt > 0);

    offset = 0;

    while (size > 0) {

        /* Find the next start position; skip all full-sized vector elements  */

        while (offset >= iov[0].iov_len) {

            offset -= iov[0].iov_len;

            iov++, iovcnt--;

        }

        /* skip `offset' bytes from the (now) first element, undo it on exit */

        assert(iovcnt > 0);

        iov[0].iov_base += offset;

        iov[0].iov_len -= offset;

        do {

            len = writev(s->fd, iov, iovcnt);

        } while (len == -1 && errno == EINTR);

        if (len == -1) {

            return -errno;

        }

        /* Undo the changes above */

        iov[0].iov_base -= offset;

        iov[0].iov_len += offset;

        /* Prepare for the next iteration */

        offset += len;

        total += len;

        size -= len;

    }

    return total;

}

static int unix_get_buffer(void *opaque, uint8_t *buf, int64_t pos, int size)

{

    QEMUFileSocket *s = opaque;

    ssize_t len;

    for (;;) {

        len = read(s->fd, buf, size);

        if (len != -1) {

            break;

        }

        if (errno == EAGAIN) {

            yield_until_fd_readable(s->fd);

        } else if (errno != EINTR) {

            break;

        }

    }

    if (len == -1) {

        len = -errno;

    }

    return len;

}

static int unix_close(void *opaque)

{

    QEMUFileSocket *s = opaque;

    close(s->fd);

    g_free(s);

    return 0;

}

static const QEMUFileOps unix_read_ops = {

    .get_fd =     socket_get_fd,

    .get_buffer = unix_get_buffer,

    .close =      unix_close

};

static const QEMUFileOps unix_write_ops = {

    .get_fd =     socket_get_fd,

    .writev_buffer = unix_writev_buffer,

    .close =      unix_close

};

QEMUFile *qemu_fdopen(int fd, const char *mode)

{

    QEMUFileSocket *s;

    if (mode == NULL ||

        (mode[0] != 'r' && mode[0] != 'w') ||

        mode[1] != 'b' || mode[2] != 0) {

        fprintf(stderr, "qemu_fdopen: Argument validity check failed\n");

        return NULL;

    }

    s = g_malloc0(sizeof(QEMUFileSocket));

    s->fd = fd;

    if (mode[0] == 'r') {

        s->file = qemu_fopen_ops(s, &unix_read_ops);

    } else {

        s->file = qemu_fopen_ops(s, &unix_write_ops);

    }

    return s->file;

}

static const QEMUFileOps socket_read_ops = {

    .get_fd =     socket_get_fd,

    .get_buffer = socket_get_buffer,

    .close =      socket_close

};

static const QEMUFileOps socket_write_ops = {

    .get_fd =     socket_get_fd,

    .writev_buffer = socket_writev_buffer,

    .close =      socket_close

};

bool qemu_file_mode_is_not_valid(const char *mode)

{

    if (mode == NULL ||

        (mode[0] != 'r' && mode[0] != 'w') ||

        mode[1] != 'b' || mode[2] != 0) {

        fprintf(stderr, "qemu_fopen: Argument validity check failed\n");

        return true;

    }

    return false;

}

QEMUFile *qemu_fopen_socket(int fd, const char *mode)

{

    QEMUFileSocket *s;

    if (qemu_file_mode_is_not_valid(mode)) {

        return NULL;

    }

    s = g_malloc0(sizeof(QEMUFileSocket));

    s->fd = fd;

    if (mode[0] == 'w') {

        qemu_set_block(s->fd);

        s->file = qemu_fopen_ops(s, &socket_write_ops);

    } else {

        s->file = qemu_fopen_ops(s, &socket_read_ops);

    }

    return s->file;

}

QEMUFile *qemu_fopen(const char *filename, const char *mode)

{

    QEMUFileStdio *s;

    if (qemu_file_mode_is_not_valid(mode)) {

        return NULL;

    }

    s = g_malloc0(sizeof(QEMUFileStdio));

    s->stdio_file = fopen(filename, mode);

    if (!s->stdio_file) {

        goto fail;

    }

    if (mode[0] == 'w') {

        s->file = qemu_fopen_ops(s, &stdio_file_write_ops);

    } else {

        s->file = qemu_fopen_ops(s, &stdio_file_read_ops);

    }

    return s->file;

fail:

    g_free(s);

    return NULL;

}

QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops)

{

    QEMUFile *f;

    f = g_malloc0(sizeof(QEMUFile));

    f->opaque = opaque;

    f->ops = ops;

    return f;

}

/*

 * Get last error for stream f

 *

 * Return negative error value if there has been an error on previous

 * operations, return 0 if no error happened.

 *

 */

int qemu_file_get_error(QEMUFile *f)

{

    return f->last_error;

}

void qemu_file_set_error(QEMUFile *f, int ret)

{

    if (f->last_error == 0) {

        f->last_error = ret;

    }

}

static inline bool qemu_file_is_writable(QEMUFile *f)

{

    return f->ops->writev_buffer || f->ops->put_buffer;

}

/**

 * Flushes QEMUFile buffer

 *

 * If there is writev_buffer QEMUFileOps it uses it otherwise uses

 * put_buffer ops.

 */

void qemu_fflush(QEMUFile *f)

{

    ssize_t ret = 0;

    if (!qemu_file_is_writable(f)) {

        return;

    }

    if (f->ops->writev_buffer) {

        if (f->iovcnt > 0) {

            ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt, f->pos);

        }

    } else {

        if (f->buf_index > 0) {

            ret = f->ops->put_buffer(f->opaque, f->buf, f->pos, f->buf_index);

        }

    }

    if (ret >= 0) {

        f->pos += ret;

    }

    f->buf_index = 0;

    f->iovcnt = 0;

    if (ret < 0) {

        qemu_file_set_error(f, ret);

    }

}

void ram_control_before_iterate(QEMUFile *f, uint64_t flags)

{

    int ret = 0;

    if (f->ops->before_ram_iterate) {

        ret = f->ops->before_ram_iterate(f, f->opaque, flags);

        if (ret < 0) {

            qemu_file_set_error(f, ret);

        }

    }

}

void ram_control_after_iterate(QEMUFile *f, uint64_t flags)

{

    int ret = 0;

    if (f->ops->after_ram_iterate) {

        ret = f->ops->after_ram_iterate(f, f->opaque, flags);

        if (ret < 0) {

            qemu_file_set_error(f, ret);

        }

    }

}

void ram_control_load_hook(QEMUFile *f, uint64_t flags)

{

    int ret = -EINVAL;

    if (f->ops->hook_ram_load) {

        ret = f->ops->hook_ram_load(f, f->opaque, flags);

        if (ret < 0) {

            qemu_file_set_error(f, ret);

        }

    } else {

        qemu_file_set_error(f, ret);

    }

}

size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,

                         ram_addr_t offset, size_t size, int *bytes_sent)

{

    if (f->ops->save_page) {

        int ret = f->ops->save_page(f, f->opaque, block_offset,

                                    offset, size, bytes_sent);

        if (ret != RAM_SAVE_CONTROL_DELAYED) {

            if (bytes_sent && *bytes_sent > 0) {

                qemu_update_position(f, *bytes_sent);

            } else if (ret < 0) {

                qemu_file_set_error(f, ret);

            }

        }

        return ret;

    }

    return RAM_SAVE_CONTROL_NOT_SUPP;

}

static void qemu_fill_buffer(QEMUFile *f)

{

    int len;

    int pending;

    assert(!qemu_file_is_writable(f));

    pending = f->buf_size - f->buf_index;

    if (pending > 0) {

        memmove(f->buf, f->buf + f->buf_index, pending);

    }

    f->buf_index = 0;

    f->buf_size = pending;

    len = f->ops->get_buffer(f->opaque, f->buf + pending, f->pos,

                        IO_BUF_SIZE - pending);

    if (len > 0) {

        f->buf_size += len;

        f->pos += len;

    } else if (len == 0) {

        qemu_file_set_error(f, -EIO);

    } else if (len != -EAGAIN) {

        qemu_file_set_error(f, len);

    }

}

int qemu_get_fd(QEMUFile *f)

{

    if (f->ops->get_fd) {

        return f->ops->get_fd(f->opaque);

    }

    return -1;

}

void qemu_update_position(QEMUFile *f, size_t size)

{

    f->pos += size;

}

/** Closes the file

 *

 * Returns negative error value if any error happened on previous operations or

 * while closing the file. Returns 0 or positive number on success.

 *

 * The meaning of return value on success depends on the specific backend

 * being used.

 */

int qemu_fclose(QEMUFile *f)

{

    int ret;

    qemu_fflush(f);

    ret = qemu_file_get_error(f);

    if (f->ops->close) {

        int ret2 = f->ops->close(f->opaque);

        if (ret >= 0) {

            ret = ret2;

        }

    }

    /* If any error was spotted before closing, we should report it

     * instead of the close() return value.

     */

    if (f->last_error) {

        ret = f->last_error;

    }

    g_free(f);

    return ret;

}

static void add_to_iovec(QEMUFile *f, const uint8_t *buf, int size)

{

    /* check for adjacent buffer and coalesce them */

    if (f->iovcnt > 0 && buf == f->iov[f->iovcnt - 1].iov_base +

        f->iov[f->iovcnt - 1].iov_len) {

        f->iov[f->iovcnt - 1].iov_len += size;

    } else {

        f->iov[f->iovcnt].iov_base = (uint8_t *)buf;

        f->iov[f->iovcnt++].iov_len = size;

    }

    if (f->iovcnt >= MAX_IOV_SIZE) {

        qemu_fflush(f);

    }

}

void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, int size)

{

    if (!f->ops->writev_buffer) {

        qemu_put_buffer(f, buf, size);

        return;

    }

    if (f->last_error) {

        return;

    }

    f->bytes_xfer += size;

    add_to_iovec(f, buf, size);

}

void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size)

{

    int l;

    if (f->last_error) {

        return;

    }

    while (size > 0) {

        l = IO_BUF_SIZE - f->buf_index;

        if (l > size) {

            l = size;

        }

        memcpy(f->buf + f->buf_index, buf, l);

        f->bytes_xfer += l;

        if (f->ops->writev_buffer) {

            add_to_iovec(f, f->buf + f->buf_index, l);

        }

        f->buf_index += l;

        if (f->buf_index == IO_BUF_SIZE) {

            qemu_fflush(f);

        }

        if (qemu_file_get_error(f)) {

            break;

        }

        buf += l;

        size -= l;

    }

}

void qemu_put_byte(QEMUFile *f, int v)

{

    if (f->last_error) {

        return;

    }

    f->buf[f->buf_index] = v;

    f->bytes_xfer++;

    if (f->ops->writev_buffer) {

        add_to_iovec(f, f->buf + f->buf_index, 1);

    }

    f->buf_index++;

    if (f->buf_index == IO_BUF_SIZE) {

        qemu_fflush(f);

    }

}

void qemu_file_skip(QEMUFile *f, int size)

{

    if (f->buf_index + size <= f->buf_size) {

        f->buf_index += size;

    }

}

int qemu_peek_buffer(QEMUFile *f, uint8_t *buf, int size, size_t offset)

{

    int pending;

    int index;

    assert(!qemu_file_is_writable(f));

    index = f->buf_index + offset;

    pending = f->buf_size - index;

    if (pending < size) {

        qemu_fill_buffer(f);

        index = f->buf_index + offset;

        pending = f->buf_size - index;

    }

    if (pending <= 0) {

        return 0;

    }

    if (size > pending) {

        size = pending;

    }

    memcpy(buf, f->buf + index, size);

    return size;

}

int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size)

{

    int pending = size;

    int done = 0;

    while (pending > 0) {

        int res;

        res = qemu_peek_buffer(f, buf, pending, 0);

        if (res == 0) {

            return done;

        }

        qemu_file_skip(f, res);

        buf += res;

        pending -= res;

        done += res;

    }

    return done;

}

int qemu_peek_byte(QEMUFile *f, int offset)

{

    int index = f->buf_index + offset;

    assert(!qemu_file_is_writable(f));

    if (index >= f->buf_size) {

        qemu_fill_buffer(f);

        index = f->buf_index + offset;

        if (index >= f->buf_size) {

            return 0;

        }

    }

    return f->buf[index];

}

int qemu_get_byte(QEMUFile *f)

{

    int result;

    result = qemu_peek_byte(f, 0);

    qemu_file_skip(f, 1);

    return result;

}

int64_t qemu_ftell(QEMUFile *f)

{

    qemu_fflush(f);

    return f->pos;

}

int qemu_file_rate_limit(QEMUFile *f)

{

    if (qemu_file_get_error(f)) {

        return 1;

    }

    if (f->xfer_limit > 0 && f->bytes_xfer > f->xfer_limit) {

        return 1;

    }

    return 0;

}

int64_t qemu_file_get_rate_limit(QEMUFile *f)

{

    return f->xfer_limit;

}

void qemu_file_set_rate_limit(QEMUFile *f, int64_t limit)

{

    f->xfer_limit = limit;

}

void qemu_file_reset_rate_limit(QEMUFile *f)

{

    f->bytes_xfer = 0;

}

void qemu_put_be16(QEMUFile *f, unsigned int v)

{

    qemu_put_byte(f, v >> 8);

    qemu_put_byte(f, v);

}

void qemu_put_be32(QEMUFile *f, unsigned int v)

{

    qemu_put_byte(f, v >> 24);

    qemu_put_byte(f, v >> 16);

    qemu_put_byte(f, v >> 8);

    qemu_put_byte(f, v);

}

void qemu_put_be64(QEMUFile *f, uint64_t v)

{

    qemu_put_be32(f, v >> 32);

    qemu_put_be32(f, v);

}

unsigned int qemu_get_be16(QEMUFile *f)

{

    unsigned int v;

    v = qemu_get_byte(f) << 8;

    v |= qemu_get_byte(f);

    return v;

}

unsigned int qemu_get_be32(QEMUFile *f)

{

    unsigned int v;

    v = qemu_get_byte(f) << 24;

    v |= qemu_get_byte(f) << 16;

    v |= qemu_get_byte(f) << 8;

    v |= qemu_get_byte(f);

    return v;

}

uint64_t qemu_get_be64(QEMUFile *f)

{

    uint64_t v;

    v = (uint64_t)qemu_get_be32(f) << 32;

    v |= qemu_get_be32(f);

    return v;

}