Date: Tue, 22 Jan 2002 11:23:46 -0800 From: Alfred Perlstein <bright@mu.org> To: David Greenman <dg@FreeBSD.org> Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern uipc_syscalls.c Message-ID: <20020122112346.A13686@elvis.mu.org> In-Reply-To: <20020122104431.X13686@elvis.mu.org>; from bright@mu.org on Tue, Jan 22, 2002 at 10:44:31AM -0800 References: <200201221732.g0MHWAR50160@freefall.freebsd.org> <20020122104431.X13686@elvis.mu.org>
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* Alfred Perlstein <bright@mu.org> [020122 10:44] wrote: > * David Greenman <dg@FreeBSD.org> [020122 09:32] wrote: > > dg 2002/01/22 09:32:10 PST > > > > Modified files: > > sys/kern uipc_syscalls.c > > Log: > > Fixed bug in calculation of amount of file to send when nbytes !=0 and > > headers or trailers are supplied. Reported by Vladislav Shabanov > > <vs@rambler-co.ru>. > > There's a problem here where people actually figured out this buggy > behaviour and worked around it, however now you've broken their > workarounds. This is why in a previous email (private I think) I > suggested you use the flags argument or make a new syscall to > implement the proper behaviour. > > see revision 1.6 of src/lib/libc_r/uthread/uthread_sendfile.c. > -or- > http://www.freebsd.org/cgi/cvsweb.cgi/src/lib/libc_r/uthread/uthread_sendfile.c?rev=1.6&content-type=text/x-cvsweb-markup > > Apache 2.x depends on the old behaviour as well. > > While you're here, you realize that sendfile's sideways return is > pretty confusing, specifically the case where non-blocking IO is > being done you can get back EAGAIN along with sbytes != 0. Most > other syscalls, (write(2), read(2)) will return a short count and > no error if they would block. > > I don't strongly object to MFC'ing this fix, but I think at least: > 1) FreeBSD version needs to be bumped in both 5.x and 4.x. > 2) If MFC'd please provide a osendfile function to not break applications. > 3) consider fixing the sideways return as well to just return a partial > count in sbytes and not an error? > (ret == -1 && errno == EAGAIN && sbytes != 0) Let me also note that I'll take care of this if you're _really_ too busy, but I'm under pressure ATM to do stuff over here as well so my time is limited but I can take a shot at it. I just wanted to make sure I'm covering all the bases wrt to maintaining compatibility for people. -- -Alfred Perlstein [alfred@freebsd.org] 'Instead of asking why a piece of software is using "1970s technology," start asking why software is ignoring 30 years of accumulated wisdom.' Tax deductable donations for FreeBSD: http://www.freebsdfoundation.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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