On 09/01/2023 13:20, Cédric Le Goater wrote:
External email: Use caution opening links or attachments
On 12/29/22 12:03, Avihai Horon wrote:
Add new function qemu_file_get_to_fd() that allows reading data from
QEMUFile and writing it straight into a given fd.
This will be used later in VFIO migration code.
Signed-off-by: Avihai Horon <avih...@nvidia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>
---
migration/qemu-file.h | 1 +
migration/qemu-file.c | 34 ++++++++++++++++++++++++++++++++++
2 files changed, 35 insertions(+)
diff --git a/migration/qemu-file.h b/migration/qemu-file.h
index fa13d04d78..9d0155a2a1 100644
--- a/migration/qemu-file.h
+++ b/migration/qemu-file.h
@@ -148,6 +148,7 @@ int qemu_file_shutdown(QEMUFile *f);
QEMUFile *qemu_file_get_return_path(QEMUFile *f);
void qemu_fflush(QEMUFile *f);
void qemu_file_set_blocking(QEMUFile *f, bool block);
+int qemu_file_get_to_fd(QEMUFile *f, int fd, size_t size);
void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index 2d5f74ffc2..79303c9d34 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -940,3 +940,37 @@ QIOChannel *qemu_file_get_ioc(QEMUFile *file)
{
return file->ioc;
}
+
+/*
+ * Read size bytes from QEMUFile f and write them to fd.
+ */
+int qemu_file_get_to_fd(QEMUFile *f, int fd, size_t size)
+{
+ while (size) {
+ size_t pending = f->buf_size - f->buf_index;
+ ssize_t rc;
+
+ if (!pending) {
+ rc = qemu_fill_buffer(f);
+ if (rc < 0) {
+ return rc;
+ }
+ if (rc == 0) {
+ return -1;
Given the call stack, -1 would be interpreted as EPERM. May be EIO
instead ?
Sure.
I will also change write (down below) to return -errno instead of rc on
error.
C.
+ }
+ continue;
+ }
+
+ rc = write(fd, f->buf + f->buf_index, MIN(pending, size));
+ if (rc < 0) {
+ return rc;
+ }
+ if (rc == 0) {
+ return -1;
+ }
+ f->buf_index += rc;
+ size -= rc;
+ }
+
+ return 0;
+}
