On Saturday 07 February 2015 15:14:10 Denys Vlasenko wrote:
> On Sat, Feb 7, 2015 at 2:32 AM, Rich Felker <dal...@libc.org> wrote:
> >> > the _r functions are for thread-safe
> >> > versions of their corresponding legacy functions, but getpwent_r has
> >> > inherent global state -- the iterator. Whoever made it just wasn't
> >> > thinking. To make a correct interface like this the caller would need
> >> > to have an iterator object to pass to the function, but I can't see
> >> > much merit in inventing a new interface for this.
> >>
> >> It doesn't matter that it makes no sense. It's glibc compat.
> >> If you want more programs rather than less to build
> >> against musl, you have to strive to be glibc-compatible where practical.
> >
> > So far we haven't hit anything wanting to use it except busybox. I'm
> > all for compatibility, but it doesn't look easy to provide without
> > ugly code duplication or similar. We're in the middle of reworking
> > some of this code anyway to add alternate backend support, so I just
> > asked about how easy it would be to get getpwent_r too, but we didn't
> > see any obvious clean ways to do it. This is basically a consequence
> > of the way musl uses a dynamic buffer for the strings (line from the
> > file) so as not to impose an arbitrary line limit,
>
> How about this implementation?
>
> int getpwent_r(struct passwd *pwbuf, char *buf, size_t buflen, struct
> passwd **pwbufp)
> {
> char *line=0;
> size_t size=0;
> if (!f) f = fopen("/etc/passwd", "rbe");
> if (!f) return 0;
Hi,
this should return ENOENT
> *pwbufp = __getpwent_a(f, pwbuf, &line, &size);
> if (!*pwbufp)
> return 0; /* success (eof) */
this should return ENOENT on EOF and 0 otherwise
or you will be stuck in infite loops.
Ciao,
Tito
PS.: maybe this is smaller (untested)?
strncpy(buf, line, buflen);
free(line);
if (size < buflen)
return 0;
*pwbufp = 0;
return errno = ERANGE;
> if (size < buflen)
> strcpy(buf, line);
> free(line);
> if (size < buflen)
> return 0; /* success */
> *pwbufp = 0;
> errno = ERANGE;
> return ERANGE;
> }
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