From: Szabolcs Nagy <nsz@port70.net>
To: musl@lists.openwall.com
Subject: Re: src/stdio/__stdio_read.c
Date: Fri, 16 Nov 2012 10:29:36 +0100 [thread overview]
Message-ID: <20121116092936.GI12537@port70.net> (raw)
In-Reply-To: <20121116114057.34884015@keeper.home.local>
* Yuri Kozlov <yuray@komyakino.ru> [2012-11-16 11:40:57 +0400]:
> size_t __stdio_read(FILE *f, unsigned char *buf, size_t len)
> {
> ssize_t cnt;
> ...
> cnt = syscall(SYS_readv, ...)
>
> if (cnt <= 0) {
> f->flags |= F_EOF ^ ((F_ERR^F_EOF) & cnt);
> f->rpos = f->rend = 0;
> return cnt;
> }
> ...
> }
>
> It not raise a problem when a signed value return as unsigned?
>
no, cnt is either 0 or -1 there (assuming readv works)
this is how __stdio_read is used (f->read):
for (; l; l-=k, dest+=k) {
k = __toread(f) ? 0 : f->read(f, dest, l);
if (k+1<=1) {
FUNLOCK(f);
return (len-l)/size;
}
}
it handles the k == -1 and k == 0 case
next prev parent reply other threads:[~2012-11-16 9:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-16 7:40 src/stdio/__stdio_read.c Yuri Kozlov
2012-11-16 9:29 ` Szabolcs Nagy [this message]
2012-11-16 19:01 ` src/stdio/__stdio_read.c Rich Felker
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