Re: [Qemu-devel] [PATCH] io: Fix QIOChannelFile when creating and opening read-write

["Daniel P. Berrange" <berrange@redhat.com>]

On Tue, Oct 31, 2017 at 04:09:02PM +0000, Ross Lagerwall wrote:
> The code wrongly passes the mode to open() only if O_WRONLY is set.
> Instead, the mode should be passed when O_CREAT is set (or O_TMPFILE on
> Linux). Fix this by always passing the mode since open() will correctly
> ignore the mode if it is not needed. Add a testcase which exercises this
> bug.
> 
> While at it, add /dev/fdset/ support to QIOChannelFile by calling
> qemu_open() instead open(). There is a subtle semantic change since
> qemu_open() automatically sets O_CLOEXEC, but this doesn't affect any of
> the users of the function.

Can you split the use of qemu_open() into a separate patch - its bad pratice
to mix two different functional changes in one patch. Also as Marc-Andre
mentions, we would need qemu_close() here too I think.

> 
> Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
> ---
>  include/io/channel-file.h    |  2 +-
>  io/channel-file.c            |  6 +-----
>  tests/test-io-channel-file.c | 27 +++++++++++++++++++++++++++
>  3 files changed, 29 insertions(+), 6 deletions(-)
> 
> diff --git a/include/io/channel-file.h b/include/io/channel-file.h
> index 79245f1..ebfe54e 100644
> --- a/include/io/channel-file.h
> +++ b/include/io/channel-file.h
> @@ -73,7 +73,7 @@ qio_channel_file_new_fd(int fd);
>   * qio_channel_file_new_path:
>   * @path: the file path
>   * @flags: the open flags (O_RDONLY|O_WRONLY|O_RDWR, etc)
> - * @mode: the file creation mode if O_WRONLY is set in @flags
> + * @mode: the file creation mode if O_CREAT is set in @flags
>   * @errp: pointer to initialized error object
>   *
>   * Create a new IO channel object for a file represented
> diff --git a/io/channel-file.c b/io/channel-file.c
> index b383273..ae8fb62 100644
> --- a/io/channel-file.c
> +++ b/io/channel-file.c
> @@ -50,11 +50,7 @@ qio_channel_file_new_path(const char *path,
>  
>      ioc = QIO_CHANNEL_FILE(object_new(TYPE_QIO_CHANNEL_FILE));
>  
> -    if (flags & O_WRONLY) {
> -        ioc->fd = open(path, flags, mode);
> -    } else {
> -        ioc->fd = open(path, flags);
> -    }
> +    ioc->fd = qemu_open(path, flags, mode);
>      if (ioc->fd < 0) {
>          object_unref(OBJECT(ioc));
>          error_setg_errno(errp, errno,
> diff --git a/tests/test-io-channel-file.c b/tests/test-io-channel-file.c
> index 6bfede6..0c7303d 100644
> --- a/tests/test-io-channel-file.c
> +++ b/tests/test-io-channel-file.c
> @@ -50,6 +50,32 @@ static void test_io_channel_file(void)
>      object_unref(OBJECT(dst));
>  }
>  
> +static void test_io_channel_file_rdwr(void)
> +{
> +    QIOChannel *src, *dst;
> +    QIOChannelTest *test;
> +
> +#define TEST_FILE "tests/test-io-channel-file.txt"
> +    unlink(TEST_FILE);
> +    src = QIO_CHANNEL(qio_channel_file_new_path(
> +                          TEST_FILE,
> +                          O_RDWR | O_CREAT | O_TRUNC | O_BINARY, 0600,
> +                          &error_abort));
> +    dst = QIO_CHANNEL(qio_channel_file_new_path(
> +                          TEST_FILE,
> +                          O_RDONLY | O_BINARY, 0,
> +                          &error_abort));
> +
> +    test = qio_channel_test_new();
> +    qio_channel_test_run_writer(test, src);
> +    qio_channel_test_run_reader(test, dst);
> +    qio_channel_test_validate(test);

Since we're specifically fixing a problem with mode, it would be good to
check the mode of the created file to show that its applied - ideally the
test would fail with previous code in this way.

> +
> +    unlink(TEST_FILE);
> +    object_unref(OBJECT(src));
> +    object_unref(OBJECT(dst));
> +}
> +

Regards,
Daniel
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