qemu-file: Move QEMUFile code to qemu-file.c

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

1 files changed, 826 insertions, 0 deletions

diff --git a/qemu-file.c b/qemu-file.c
new file mode 100644
index 0000000000..9473b674ba
--- /dev/null
+++ b/qemu-file.c
@@ -0,0 +1,826 @@
+#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;
+}