On 07/01/2018 09:49 PM, xinhua.Cao wrote:
> In the tcp_chr_write function, we checked errno,
> but errno was not reset before a read or write operation.
> Therefore, this check of errno's actions is often
> incorrect after EAGAIN has occurred.
> We reset errno before reading and writing to
> ensure the correctness of errno's judgment
>
> Signed-off-by: xinhua.Cao <caoxin...@huawei.com>
Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org>
> ---
> chardev/char-fe.c | 1 +
> chardev/char.c | 2 ++
> 2 files changed, 3 insertions(+)
>
> diff --git a/chardev/char-fe.c b/chardev/char-fe.c
> index b1f228e..d96ca6f 100644
> --- a/chardev/char-fe.c
> +++ b/chardev/char-fe.c
> @@ -69,6 +69,7 @@ int qemu_chr_fe_read_all(CharBackend *be, uint8_t *buf, int
> len)
>
> while (offset < len) {
> retry:
> + errno = 0;
> res = CHARDEV_GET_CLASS(s)->chr_sync_read(s, buf + offset,
> len - offset);
> if (res == -1 && errno == EAGAIN) {
> diff --git a/chardev/char.c b/chardev/char.c
> index 76d866e..3387442 100644
> --- a/chardev/char.c
> +++ b/chardev/char.c
> @@ -85,6 +85,7 @@ static void qemu_chr_write_log(Chardev *s, const uint8_t
> *buf, size_t len)
>
> while (done < len) {
> retry:
> + errno = 0;
> ret = write(s->logfd, buf + done, len - done);
> if (ret == -1 && errno == EAGAIN) {
> g_usleep(100);
> @@ -109,6 +110,7 @@ static int qemu_chr_write_buffer(Chardev *s,
> qemu_mutex_lock(&s->chr_write_lock);
> while (*offset < len) {
> retry:
> + errno = 0;
> res = cc->chr_write(s, buf + *offset, len - *offset);
> if (res < 0 && errno == EAGAIN && write_all) {
> g_usleep(100);
>
