Bug#520744: _SC_GETGR_R_SIZE_MAX returned on amd64 too small
On Fri, Apr 24, 2009 at 12:27:49PM +0200, Aurelien Jarno wrote:
[..snip..]
> That said I don't fully understand POSIX here. What should happen if a
> line in /etc/group needs more memory than sysconf(_SC_GETGR_R_SIZE_MAX)?
> The line should be truncated? As far as I understand user can create as
> many entries as he wants there, so _SC_GETGR_R_SIZE_MAX can only be
> defined to an arbitrary value.
The manpage (as well as posix) says:
The maximum needed size for buf can be found using sysconf(3) with the argument _SC_GETGR_R_SIZE_MAX.
I don't understand how this is supposed to work with arbitrary large
groups given that gr_mem is part of the buffer. It's probaly just a
documentation bug that should read "minimum" instead of "maximum"?
Since sysconf is allowed to return -1 we need to check for ERANE anyway,
see e.g. [1].
Cheers,
-- Guido
[1] http://git.debian.org/?p=pkg-libvirt/libvirt.git;a=blob;f=debian/patches/0005-increase-buffer-on-ERANGE.patch;h=7b0d76354258ba6d5f45759444a5e6ba03680c70;hb=031b9c1f5491617ad17b4d74e2a039de37d982f6
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