svn commit: r215475 - stable/8/lib/libusb

[Andrew Thompson]

On 20 November 2010 04:21, Jilles Tjoelker <jilles at stack.nl> wrote:
> On Fri, Nov 19, 2010 at 01:17:49AM +0000, Andrew Thompson wrote:
>> Author: thompsa
>> Date: Fri Nov 19 01:17:49 2010
>> New Revision: 215475
>> URL: http://svn.freebsd.org/changeset/base/215475
>
>> Log:
>>   MFC r203774
>
>>    Use more standard way for setting nonblocking flag for a filedescriptor.
>>    This makes libusb porting a bit easier.
>
>> Modified:
>>   stable/8/lib/libusb/libusb10.c
>> Directory Properties:
>>   stable/8/lib/libusb/   (props changed)
>>   stable/8/lib/libusb/usb.h   (props changed)
>>
>> Modified: stable/8/lib/libusb/libusb10.c
>> ==============================================================================
>> --- stable/8/lib/libusb/libusb10.c    Thu Nov 18 23:46:55 2010        (r215474)
>> +++ stable/8/lib/libusb/libusb10.c    Fri Nov 19 01:17:49 2010        (r215475)
> [...]
>> @@ -105,10 +105,12 @@ libusb_init(libusb_context **context)
>>               return (LIBUSB_ERROR_OTHER);
>>       }
>>       /* set non-blocking mode on the control pipe to avoid deadlock */
>> -     ret = 1;
>> -     ioctl(ctx->ctrl_pipe[0], FIONBIO, &ret);
>> -     ret = 1;
>> -     ioctl(ctx->ctrl_pipe[1], FIONBIO, &ret);
>> +     flag = 1;
>> +     ret = fcntl(ctx->ctrl_pipe[0], O_NONBLOCK, &flag);
>> +     assert(ret != -1 && "Couldn't set O_NONBLOCK for ctx->ctrl_pipe[0]");
>> +     flag = 1;
>> +     ret = fcntl(ctx->ctrl_pipe[1], O_NONBLOCK, &flag);
>> +     assert(ret != -1 && "Couldn't set O_NONBLOCK for ctx->ctrl_pipe[1]");
>>
>>       libusb10_add_pollfd(ctx, &ctx->ctx_poll, NULL, ctx->ctrl_pipe[0], POLLIN);
>
> This is not the correct way to use fcntl() to turn on non-blocking mode.
> The correct way is
>
>        flag = fcntl(ctx->ctrl_pipe[0], F_GETFL, 0);
>        if (flag != -1) {
>                ret = fcntl(ctx->ctrl_pipe[0], F_SETFL, flag | O_NONBLOCK);
>                if (ret == -1)
>                        handle_error();
>        } else
>                handle_error();
>
> substituting some sort of error handling for handle_error().
>
> This has been fixed in head in r213853, but that commit also makes other
> changes.
>
> It turns out that on FreeBSD both F_SETFL and O_NONBLOCK have the value
> 4, so there is some chance the desired result is achieved and fcntl()
> will not fail. It may also set other flags for the open file
> description, which could lead to unexpected results.

I have merged r213853 now.