Re: [ITP] libfakesu 1.0

["D. Boland" <daniel at boland dot nl>]

Hi Christian,

Christian Franke wrote:
> 
> D. Boland wrote:
> > Christian Franke wrote:
> >> D. Boland wrote:
> >>> http://cygwin.boland.nl/x86/release/libfakesu/
> >> A few notes regarding cygfakesu.c:
> >>
> >>> uid_t root_uid = 18;
> >>> gid_t root_gid = 544;
> >>>
> >>> uid_t my_uid = -1;
> >>> gid_t my_gid = -1;
> >>>
> >>> struct passwd my_pw;
> >>> struct group my_grp;
> >>>
> >>> char str255[255];
> >>> ...
> >>> uid_t uid_get(uid_t uid){
> >>> ...
> >>> gid_t gid_get(gid_t gid){
> >>> ...
> >>> etc...
> >> Variables and functions not exported by the fakesu.h file should be
> >> declared as static. Note that the cygfakesu.def file has no effect when
> >> generating a static lib.
> > I added 'static' for un-exported symbols. Removed cygfakesu.def.
> 
> Thanks.
> 
> BTW: All these variables except root_uid/gid are not needed as static
> globals:
> 
> my_uid is only used to pass the uid from uid_get/set() to get/set(e)uid().
> 
> my_pw and str255 are only needed because su_getpwnam() calls
> getpwnam_r() instead of getpwnam().

I did that to avoid writing into 'external' memory. Would calling getpwnam directly
be thread-safe?

> 
> etc.
> 
> >>> int su_setgroups(int size, const gid_t *list){
> >>> ...
> >>>      gid_t l[s];
> >>> ...
> >>>      return setgroups(size, &l);
> >> setgroups() 2nd parameter expects a type compatible to 'pointer to const
> >> git_t'
> >> The type of '&l' is 'pointer to array of git_t' :-)
> >> (cosmetic in C, compilation would fail in C++):
> > I added typecasting, like this:
> >
> >       return setgroups(size, (gid_t *) &l);
> 
> No cast is needed, simply remove the '&' operator:
> 
>    return setgroups(size, l);
> 
> Remember that a C array is implicitly converted to 'pointer to first
> element' in many cases, including the above.
> 
> Another unrelated suggestion:
> 
> Add defines to fakesu.h for other uid/gid related functions which are
> not implemented by fakesu:
> 
> #define setreuid(a,b)  getruid_MISSING(a,b)
> #define getpwnam_r(a,b,c,d,e)  getpwnam_r_MISSING(a,b,c,d,e)
> ...

I'll implement the missing functions.

Daniel