Date: Sun, 23 Oct 2011 23:52:31 +0200 From: "Christopher J. Ruwe" <cjr@cruwe.de> To: <freebsd-hackers@freebsd.org> Subject: _SC_GETPW_R_SIZE_MAX undefined in sysconf.c, what is correct value? Message-ID: <20111023235231.71f73ea3@dijkstra>
next in thread | raw e-mail | index | archive | help
[-- Attachment #1 --]
I need to get the maximum size of an pwd-entry to determine the correct
buffersize for calling getpwnam_r("uname",&pwd, buf, bufsize, &pwdp). I
would like to use sysconf(_SC_GETPW_R_SIZE_MAX) to determine bufsize,
which unfornutately fails (returns -1). Currently, I used 16384, which
seems to be too much, bit works for the time being.
From recent mails I get that _SC_GETPW_R_SIZE_MAX is not available on FreeBSD, e.g., http://lists.freebsd.org/pipermail/freebsd-ports-bugs/2009-September/173081.html and http://www.redhat.com/archives/libvir-list/2011-May/msg01013.html. This assertion seems to be backed by /usr/srclib/libc/gen/sysconf.c, line 374.
From Stevens & Rago, Adavanced Programming in the UNIX Environment, I can get that FreeBSD supports all possible members in the passwd structure, but where can I determine the maximum size of these so that I can calculate the ax size of the pwd struct therefrom? Does anybody know or know where to look what maximum size a pwd-entry can have?
Knowing the maximum size a pwd structure can have, it seems like to be an idea to define the correct value in sysconf.c. As that is not done though suggested in the code, are there any obstacles in defining that value so nobody has done that so far?
Thanks for any help, cheers,
--
Christopher J. Ruwe
TZ GMT + 2
[-- Attachment #2 --]
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.18 (FreeBSD)
iQIcBAEBAgAGBQJOpIymAAoJEJTIKW/o3iwUwHsP/A7EMfLFaT57uxIrF2aQ9QQC
cmNsRnIOtisvAyMDsLZP4uepjX7gK0H2y7jOa8R3XpoxrCVri2MLAgKhaLosMB/X
u1jbLzdaSeFW8hsUej9Jcm56fdA9aKGSaasVQt0H5fQuoFqjakijQ75Ao3pQvUbr
8VpiwBTUNDFN/HLssgkylXrbrIyzij2V1SUhp4eUmwOWeovfQgO4j2DZos19fxh+
8OJxMz9W52z60O+TPhywLlH1Urx5dulAg2DM0uLqFOzYdjnuqXqQsLB+NmDUCJLb
tqD15nc62jWI7CGcmlRJJhwk9xt8JHw/N6AfDKzG1pD2hQhOsHRt22InDdJj90S6
ip6ScxrgH0cobYFrFsmwnjm6zcTX6Kggr1H17W3UWp90vMT3tGphT6vydJBLHfuO
7nIbpQTs4CawcGD3hfaC64fvmpkp0MDAJbUnUfLSV2BSXj1NjZJXLVSx0FUYZEBJ
ymRgy6NDuU+H7yi9iMPxhAQ5JBmB35TESAMY3QbPir0ARJ03McNN0IGaeHdDXU/9
GOHY9kNOQRDfpt0+iMvI/LH8StG/Cm/fhI7oFSKJ47gyP2AgwrJfvyYhJvr7T78p
EsoIG8ocXO6cCtIN9JRCEBcO8f+EYdFpI2U9csP05+srrt/vpAfg7CZ4vqtIuHdO
FtTqn9JG68195QkxtcG0
=6mH+
-----END PGP SIGNATURE-----
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20111023235231.71f73ea3>