On 2014/01/30 11:32, Jérémie Courrèges-Anglas wrote: > will...@25thandclement.com writes: > > >>Synopsis: Bad return value for getpwnam_r et al > >>Category: 42 > >>Environment: > > System : OpenBSD 5.4 > > Details : OpenBSD 5.4 (GENERIC.MP) #41: Tue Jul 30 15:30:02 MDT 2013 > > > > dera...@amd64.openbsd.org:/usr/src/sys/arch/amd64/compile/GENERIC.MP > > > > Architecture: OpenBSD.amd64 > > Machine : amd64 > >>Description: > > POSIX says "[t]he getpwnam_r() function shall return zero on success > > or if the requested entry was not found and no error has occurred. > > If an error has occurred, an error number shall be returned to > > indicate the error." > > > > However, OpenBSD returns 0 on success or 1 on failure; it doesn't > > return an error number. Linux, OS X, Solaris, FreeBSD, and NetBSD > > all return an error number, and in particular return ERANGE when the > > provided buffer is too small.
I don't disagree with this.. http://pubs.opengroup.org/onlinepubs/009695399/functions/getpwnam.html "If successful, the getpwnam_r() function shall return zero; otherwise, an error number shall be returned to indicate the error." > > Background: I was looping over getpwnam_r so I wouldn't have to use > > sysconf() to get _SC_GETPW_R_SIZE_MAX. Linux/glibc has an annoying > > habit of setting some limits to INT_MAX. It doesn't in this case, > > but I'm not confident they won't do something stupid down the line. ..but doing a bunch of reallocs to work-around a case of them possibly breaking something in the future seems like overkill? just checking for malloc failure (which should be done anyway) and printing a good diagnostic would surely be enough to point the blame if a bug of this nature creeps into glibc.. > > int main(void) { > > struct passwd ent, *found; > > char *buf = NULL; > > size_t bufsiz = 1; > > int error; > > > > found = NULL; > > > > buf = malloc(bufsiz); > > > > while ((error = getpwnam_r("root", &ent, buf, bufsiz, &found))) > > { > > fprintf(stderr, "bufsiz:%zu error:%s\n", bufsiz, > > strerror(error)); > > ^^^^^ > I think you mean errno, not error. errno for getpwnam, but this is getpwnam_r, generally the thread-safe functions specify returning an error code in addition to setting errno.
