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/*
Copyright (c) 2016, Antonio SJ Musumeci <trapexit@spawn.link>
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "rnd.hpp"
#include <grp.h>
#include <pwd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#if defined __linux__ and UGID_USE_RWLOCK == 0
# include <sys/syscall.h>
#elif __APPLE__
# include <sys/param.h>
#endif
#include <cassert>
#include <cstdlib>
#include <algorithm>
#include <unordered_map>
#include <mutex>
#include "gidcache.hpp"
std::mutex g_REGISTERED_CACHES_MUTEX;
std::unordered_map<pthread_t,GIDCache*> g_REGISTERED_CACHES;
inline
bool
GIDRecord::operator<(const struct GIDRecord &b) const
{
return uid < b.uid;
}
GIDCache::GIDCache()
: invalidate(false),
size(0),
recs()
{
std::lock_guard<std::mutex> guard(g_REGISTERED_CACHES_MUTEX);
bool inserted;
pthread_t pthid;
pthid = pthread_self();
inserted = g_REGISTERED_CACHES.emplace(pthid,this).second;
assert(inserted == true);
}
inline
GIDRecord *
GIDCache::begin(void)
{
return &recs[0];
}
inline
GIDRecord *
GIDCache::end(void)
{
return &recs[size];
}
inline
GIDRecord *
GIDCache::allocrec(void)
{
if(size == MAXRECS)
return &recs[RND::rand64(MAXRECS)];
else
return &recs[size++];
}
inline
GIDRecord *
GIDCache::lower_bound(GIDRecord *begin,
GIDRecord *end,
const uid_t uid)
{
int step;
int count;
GIDRecord *iter;
count = std::distance(begin,end);
while(count > 0)
{
iter = begin;
step = count / 2;
std::advance(iter,step);
if(iter->uid < uid)
{
begin = ++iter;
count -= step + 1;
}
else
{
count = step;
}
}
return begin;
}
static
int
_getgrouplist(const char *user,
const gid_t group,
gid_t *groups,
int *ngroups)
{
#if __APPLE__
return ::getgrouplist(user,group,(int*)groups,ngroups);
#else
return ::getgrouplist(user,group,groups,ngroups);
#endif
}
GIDRecord *
GIDCache::cache(const uid_t uid,
const gid_t gid)
{
int rv;
char buf[4096];
struct passwd pwd;
struct passwd *pwdrv;
GIDRecord *rec;
rec = allocrec();
rec->uid = uid;
rv = ::getpwuid_r(uid,&pwd,buf,sizeof(buf),&pwdrv);
if(pwdrv != NULL && rv == 0)
{
rec->size = 0;
::_getgrouplist(pwd.pw_name,gid,NULL,&rec->size);
rec->size = std::min(MAXGIDS,rec->size);
rv = ::_getgrouplist(pwd.pw_name,gid,rec->gids,&rec->size);
if(rv == -1)
{
rec->gids[0] = gid;
rec->size = 1;
}
}
return rec;
}
static
inline
int
setgroups(const GIDRecord *rec)
{
#if defined __linux__ and UGID_USE_RWLOCK == 0
# if defined SYS_setgroups32
return ::syscall(SYS_setgroups32,rec->size,rec->gids);
# else
return ::syscall(SYS_setgroups,rec->size,rec->gids);
# endif
#else
return ::setgroups(rec->size,rec->gids);
#endif
}
int
GIDCache::initgroups(const uid_t uid,
const gid_t gid)
{
int rv;
GIDRecord *rec;
if(invalidate)
{
size = 0;
invalidate = false;
}
rec = lower_bound(begin(),end(),uid);
if(rec == end() || rec->uid != uid)
{
rec = cache(uid,gid);
rv = ::setgroups(rec);
std::sort(begin(),end());
}
else
{
rv = ::setgroups(rec);
}
return rv;
}
void
GIDCache::invalidate_all_caches()
{
std::lock_guard<std::mutex> guard(g_REGISTERED_CACHES_MUTEX);
for(auto &p : g_REGISTERED_CACHES)
p.second->invalidate = true;
}