Re: [Qemu-devel] [PATCH v3 03/15] add qemu_send_full and qemu_recv_full

[Paolo Bonzini <pbonzini@redhat.com>]

On 10/14/2011 12:16 PM, Paolo Bonzini wrote:
> On 10/14/2011 11:52 AM, Kevin Wolf wrote:
>> Am 05.10.2011 09:17, schrieb Paolo Bonzini:
>>> Signed-off-by: Paolo Bonzini<pbonzini@redhat.com>
>>> ---
>>> osdep.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>> qemu-common.h | 4 +++
>>> 2 files changed, 71 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/osdep.c b/osdep.c
>>> index 56e6963..718a25d 100644
>>> --- a/osdep.c
>>> +++ b/osdep.c
>>> @@ -166,3 +166,70 @@ int qemu_accept(int s, struct sockaddr *addr,
>>> socklen_t *addrlen)
>>>
>>> return ret;
>>> }
>>> +
>>> +/*
>>> + * A variant of send(2) which handles partial write.
>>> + *
>>> + * Return the number of bytes transferred, which is only
>>> + * smaller than `count' if there is an error.
>>> + *
>>> + * This function won't work with non-blocking fd's.
>>> + * Any of the possibilities with non-bloking fd's is bad:
>>> + * - return a short write (then name is wrong)
>>> + * - busy wait adding (errno == EAGAIN) to the loop
>>> + */
>>> +ssize_t qemu_send_full(int fd, const void *buf, size_t count, int
>>> flags)
>>> +{
>>> + ssize_t ret = 0;
>>> + ssize_t total = 0;
>>> +
>>> + while (count) {
>>> + ret = send(fd, buf, count, flags);
>>> + if (ret< 0) {
>>> + if (errno == EINTR) {
>>> + continue;
>>> + }
>>> + break;
>>> + }
>>> +
>>> + count -= ret;
>>> + buf += ret;
>>> + total += ret;
>>> + }
>>> +
>>> + return total;
>>> +}
>>> +
>>> +/*
>>> + * A variant of recv(2) which handles partial write.
>>> + *
>>> + * Return the number of bytes transferred, which is only
>>> + * smaller than `count' if there is an error.
>>> + *
>>> + * This function won't work with non-blocking fd's.
>>> + * Any of the possibilities with non-bloking fd's is bad:
>>> + * - return a short write (then name is wrong)
>>> + * - busy wait adding (errno == EAGAIN) to the loop
>>> + */
>>> +ssize_t qemu_recv_full(int fd, const void *buf, size_t count, int
>>> flags)
>>> +{
>>> + ssize_t ret = 0;
>>> + ssize_t total = 0;
>>> +
>>> + while (count) {
>>> + ret = recv(fd, buf, count, flags);
>>
>> osdep.c: In function 'qemu_recv_full':
>> osdep.c:220: error: passing argument 2 of 'recv' discards qualifiers
>> from pointer target type
>> /usr/include/bits/socket2.h:35: note: expected 'void *' but argument is
>> of type 'const void *'
>
> It's fixed in 4/15's osdep.c. I attach the diff, and pushed the fixed
> version to github nbd-trim.
>
> Also, all branches there are now rebased on top of block branch.

Let's keep this out of 1.0 (having to choose I very much choose scsi 
over nbd! :)).  I'll try to get all the prerequisites in though, so that 
they will get thorough testing and the nbd parts will be easier to 
manage afterwards.

Paolo