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/* ISC license. */
#include <sys/types.h>
#include <pwd.h>
#include <grp.h>
#include <limits.h>
#include <skalibs/uint64.h>
#include <skalibs/gidstuff.h>
#include <skalibs/bytestr.h>
#include <skalibs/sgetopt.h>
#include <skalibs/strerr2.h>
#include <skalibs/env.h>
#include <skalibs/fmtscan.h>
#include <skalibs/djbunix.h>
#define USAGE "s6-envuidgid [ -i | -D defaultuid:defaultgid ] [ -u | -g | -B ] [ -n ] account prog..."
#define dieusage() strerr_dieusage(100, USAGE)
int main (int argc, char *const *argv, char const *const *envp)
{
char const *user = 0 ;
char const *group = 0 ;
int what = 0 ;
int numfallback = 0 ;
int insist = 1 ;
unsigned int pos ;
uint64 uid ;
gid_t gid ;
char fmt[19 + UINT64_FMT + (NGROUPS_MAX+1) * GID_FMT] ;
PROG = "s6-envuidgid" ;
{
subgetopt_t l = SUBGETOPT_ZERO ;
for (;;)
{
register int opt = subgetopt_r(argc, (char const *const *)argv, "ugBniD:", &l) ;
if (opt == -1) break ;
switch (opt)
{
case 'u' : what = 1 ; break ;
case 'g' : what = 2 ; break ;
case 'B' : what = 3 ; break ;
case 'n' : what = 3 ; numfallback = 1 ; break ;
case 'i' : insist = 1 ; break ;
case 'D' :
{
unsigned int pos = uint64_scan(l.arg, &uid) ;
if (!pos)
{
if (l.arg[pos] != ':') dieusage() ;
uid = 0 ;
}
if (!l.arg[pos]) gid = 0 ;
else
{
if (l.arg[pos++] != ':') dieusage() ;
if (!l.arg[pos]) gid = 0 ;
else if (!gid0_scan(l.arg + pos, &gid)) dieusage() ;
}
insist = 0 ;
what = 3 ;
break ;
}
default : dieusage() ;
}
}
argc -= l.ind ; argv += l.ind ;
}
if (argc < 2) dieusage() ;
switch (what)
{
case 0 : /* account */
case 1 : /* user */
user = argv[0] ;
break ;
case 2 : /* group */
group = argv[0] ;
break ;
case 3 : /* both */
user = argv[0] ;
pos = str_chr(argv[0], ':') ;
if (argv[0][pos])
{
argv[0][pos] = 0 ;
group = argv[0] + pos + 1 ;
if (!pos) user = 0 ;
}
break ;
default : strerr_dief1x(101, "inconsistent option management - please submit a bug-report") ;
}
pos = 0 ;
if (group)
{
struct group *gr = getgrnam(group) ;
if (gr) gid = gr->gr_gid ;
else if (numfallback && gid_scan(group, &gid)) ;
else if (insist) strerr_dief2x(1, "unknown group: ", group) ;
byte_copy(fmt + pos, 4, "GID=") ; pos += 4 ;
pos += gid_fmt(fmt + pos, gid) ;
fmt[pos++] = 0 ;
}
if (user)
{
struct passwd *pw = getpwnam(user) ;
if (pw)
{
uid = pw->pw_uid ;
if (!what)
{
gid_t tab[NGROUPS_MAX] ;
int n = prot_readgroups(argv[0], tab, NGROUPS_MAX) ;
if (n < 0)
strerr_diefu2sys(111, "get supplementary groups for ", argv[0]) ;
byte_copy(fmt + pos, 4, "GID=") ; pos += 4 ;
pos += gid_fmt(fmt + pos, pw->pw_gid) ;
byte_copy(fmt + pos, 9, "\0GIDLIST=") ; pos += 9 ;
pos += gid_fmtlist(fmt + pos, tab, n) ;
fmt[pos++] = 0 ;
}
}
else if (numfallback && uint64_scan(user, &uid)) ;
else if (insist) strerr_dief2x(1, "unknown user: ", user) ;
byte_copy(fmt + pos, 4, "UID=") ; pos += 4 ;
pos += uint64_fmt(fmt + pos, uid) ;
fmt[pos++] = 0 ;
}
pathexec_r((char const *const *)argv + 1, envp, env_len(envp), fmt, pos) ;
strerr_dieexec(111, argv[1]) ;
}
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