s6

Mirror/fork of https://skarnet.org/software/s6/
git clone https://ccx.te2000.cz/git/s6
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s6-applyuidgid.c (2093B)

      1 /* ISC license. */
      2 
      3 #include <unistd.h>
      4 #include <grp.h>
      5 #include <limits.h>
      6 #include <stdlib.h>
      7 
      8 #include <skalibs/types.h>
      9 #include <skalibs/setgroups.h>
     10 #include <skalibs/strerr.h>
     11 #include <skalibs/sgetopt.h>
     12 #include <skalibs/djbunix.h>
     13 #include <skalibs/exec.h>
     14 
     15 #define USAGE "s6-applyuidgid [ -z ] [ -u uid ] [ -g gid ] [ -G gidlist ] [ -U ] prog..."
     16 #define dieusage() strerr_dieusage(100, USAGE)
     17 
     18 int main (int argc, char const *const *argv)
     19 {
     20   uid_t uid = 0 ;
     21   gid_t gid = 0 ;
     22   gid_t gids[NGROUPS_MAX+1] ;
     23   size_t gidn = (size_t)-1 ;
     24   int unexport = 0 ;
     25   PROG = "s6-applyuidgid" ;
     26   {
     27     subgetopt l = SUBGETOPT_ZERO ;
     28     for (;;)
     29     {
     30       int opt = subgetopt_r(argc, argv, "zUu:g:G:", &l) ;
     31       if (opt == -1) break ;
     32       switch (opt)
     33       {
     34         case 'z' : unexport = 1 ; break ;
     35         case 'u' : if (!uid0_scan(l.arg, &uid)) dieusage() ; break ;
     36         case 'g' : if (!gid0_scan(l.arg, &gid)) dieusage() ; break ;
     37         case 'G' : if (!gid_scanlist(gids, NGROUPS_MAX, l.arg, &gidn) && *l.arg) dieusage() ; break ;
     38         case 'U' :
     39         {
     40           char const *x = getenv("UID") ;
     41           if (!x) strerr_dienotset(100, "UID") ;
     42           if (!uid0_scan(x, &uid)) strerr_dieinvalid(100, "UID") ;
     43           x = getenv("GID") ;
     44           if (!x) strerr_dienotset(100, "GID") ;
     45           if (!gid0_scan(x, &gid)) strerr_dieinvalid(100, "GID") ;
     46           x = getenv("GIDLIST") ;
     47           if (!x) strerr_dienotset(100, "GIDLIST") ;
     48           if (!gid_scanlist(gids, NGROUPS_MAX+1, x, &gidn) && *x)
     49             strerr_dieinvalid(100, "GIDLIST") ;
     50           break ;
     51         }
     52         default : dieusage() ;
     53       }
     54     }
     55     argc -= l.ind ; argv += l.ind ;
     56   }
     57   if (!argc) dieusage() ;
     58 
     59   if (gidn != (size_t)-1 && setgroups_and_gid(gid ? gid : getegid(), gidn, gids) < 0)
     60     strerr_diefu1sys(111, "set supplementary group list") ;
     61   if (gid && setgid(gid) < 0)
     62     strerr_diefu1sys(111, "setgid") ;
     63   if (uid && setuid(uid) < 0)
     64     strerr_diefu1sys(111, "setuid") ;
     65 
     66   if (unexport) xmexec_n(argv, "UID\0GID\0GIDLIST", 16, 3) ;
     67   else xexec(argv) ;
     68 }