The following reply was made to PR kern/163076; it has been noted by GNATS.
From: Jaakko Heinonen <[email protected]> To: Poul-Henning Kamp <[email protected]> Cc: Petr Salinger <[email protected]>, [email protected], [email protected], [email protected] Subject: Re: kern/163076: It is not possible to read in chunks from linprocfs and procfs. Date: Sun, 11 Dec 2011 12:26:08 +0200 On 2011-12-10, Poul-Henning Kamp wrote: > I agree with Dag-Erling that it is at least mistake to not have > separate sbuf(9) and sbuf(3) pages, possibly also a mistake that > they share the implementation. One problem is the different malloc() semantics. The kernel version uses M_WAITOK allocations while user space malloc(3) can fail. > Obviously sbuf_finish() should return the error status, and its > return value SHALL be checked by applications, before the contents > of the sbuf can be used. Only 21 of 133 calls I grepped through the FreeBSD source tree did check the return value. In practice SBUF_AUTOEXTEND buffers can't fail when the kernel version is used (due to M_WAITOK malloc). > The argument relating to this bug is about what sbuf_len() and > sbuf_data() should return for an error'ed sbuf. > > Given that the mandatory error-check of the sbuf_finish() call > should prevent these two functions from being called in the first > place, I'm tempted to say that their return values should be > documented as undefined, and implemented to cause the maxium amount > of havoc (ie: -1 and NULL). -- Jaakko _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-bugs To unsubscribe, send any mail to "[email protected]"
