lustre/tests/runas.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  */
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <unistd.h>
   7 #include <string.h>
   8 #include <errno.h>
   9 #include <ctype.h>
  10 #include <sys/types.h>
  11 #include <pwd.h>
  12 #include <grp.h>
  13 #include <sys/wait.h>
  14
  15 #define DEBUG 0
  16
  17 #ifndef NGROUPS_MAX
  18 #define NGROUPS_MAX 32
  19 #endif
  20
  21 static const char usage[] =
  22 "Usage: %s -u user_id [-g grp_id] [-G[gid0,gid1,...]] command\n"
  23 "  -u user_id           switch to UID user_id\n"
  24 "  -g grp_id            switch to GID grp_id\n"
  25 "  -G[gid0,gid1,...]    set supplementary groups\n";
  26
  27 void Usage_and_abort(const char *name)
  28 {
  29         fprintf(stderr, usage, name);
  30         exit(-1);
  31 }
  32
  33 int main(int argc, char **argv)
  34 {
  35         char **my_argv, *name = argv[0], *grp;
  36         int status, c, i;
  37         int gid_is_set = 0, uid_is_set = 0, num_supp = -1;
  38         uid_t user_id = 0;
  39         gid_t grp_id = 0, supp_groups[NGROUPS_MAX] = { 0 };
  40
  41         if (argc == 1) {
  42                 fprintf(stderr, "No parameter count\n");
  43                 Usage_and_abort(name);
  44         }
  45
  46         // get UID and GID
  47         while ((c = getopt(argc, argv, "+u:g:hG::")) != -1) {
  48                 switch (c) {
  49                 case 'u':
  50                         if (!isdigit(optarg[0])) {
  51                                 struct passwd *pw = getpwnam(optarg);
  52                                 if (pw == NULL) {
  53                                         fprintf(stderr, "parameter '%s' bad\n",
  54                                                 optarg);
  55                                         Usage_and_abort(name);
  56                                 }
  57                                 user_id = pw->pw_uid;
  58                         } else {
  59                                 user_id = (uid_t)atoi(optarg);
  60                         }
  61                         uid_is_set = 1;
  62                         if (!gid_is_set)
  63                                 grp_id = user_id;
  64                         break;
  65
  66                 case 'g':
  67                         if (!isdigit(optarg[0])) {
  68                                 struct group *gr = getgrnam(optarg);
  69                                 if (gr == NULL) {
  70                                         fprintf(stderr, "getgrname %s failed\n",
  71                                                 optarg);
  72                                         Usage_and_abort(name);
  73                                 }
  74                                 grp_id = gr->gr_gid;
  75                         } else {
  76                                 grp_id = (gid_t)atoi(optarg);
  77                         }
  78                         gid_is_set = 1;
  79                         break;
  80
  81                 case 'G':
  82                         num_supp = 0;
  83                         if (optarg == NULL || !isdigit(optarg[0]))
  84                                 break;
  85                         while ((grp = strsep(&optarg, ",")) != NULL) {
  86                                 printf("adding supp group %d\n", atoi(grp));
  87                                 supp_groups[num_supp++] = atoi(grp);
  88                                 if (num_supp >= NGROUPS_MAX)
  89                                         break;
  90                         }
  91                         break;
  92
  93                 default:
  94                 case 'h':
  95                         Usage_and_abort(name);
  96                         break;
  97                 }
  98         }
  99
 100         if (!uid_is_set) {
 101                 fprintf(stderr, "Must specify uid to run.\n");
 102                 Usage_and_abort(name);
 103         }
 104
 105         if (optind == argc) {
 106                 fprintf(stderr, "Must specify command to run.\n");
 107                 Usage_and_abort(name);
 108         }
 109
 110         // assemble the command
 111         my_argv = (char**)malloc(sizeof(char*)*(argc+1-optind));
 112         if (my_argv == NULL) {
 113                 fprintf(stderr, "Error in allocating memory. (%s)\n",
 114                         strerror(errno));
 115                 exit(-1);
 116         }
 117
 118         for (i = optind; i < argc; i++) {
 119                 my_argv[i-optind] = argv[i];
 120                 //printf("%s\n",my_argv[i-optind]);
 121         }
 122         my_argv[i-optind] = NULL;
 123
 124 #if DEBUG
 125         system("whoami");
 126 #endif
 127
 128         // set GID
 129         status = setregid(grp_id, grp_id);
 130         if (status == -1) {
 131                  fprintf(stderr, "Cannot change grp_ID to %d, errno=%d (%s)\n",
 132                          grp_id, errno, strerror(errno) );
 133                  exit(-1);
 134         }
 135
 136         if (num_supp >= 0) {
 137                 status = setgroups(num_supp, supp_groups);
 138                 if (status == -1) {
 139                         perror("setting supplementary groups");
 140                         exit(-1);
 141                 }
 142         }
 143
 144         // set UID
 145         status = setreuid(user_id, user_id );
 146         if(status == -1) {
 147                   fprintf(stderr,"Cannot change user_ID to %d, errno=%d (%s)\n",
 148                            user_id, errno, strerror(errno) );
 149                   exit(-1);
 150         }
 151
 152         fprintf(stderr, "running as UID %d, GID %d", user_id, grp_id);
 153         for (i = 0; i < num_supp; i++)
 154                 fprintf(stderr, ":%d", supp_groups[i]);
 155         fprintf(stderr, "\n");
 156
 157         for (i = 0; i < argc - optind; i++)
 158                  fprintf(stderr, " [%s]", my_argv[i]);
 159
 160         fprintf(stderr, "\n");
 161         fflush(stderr);
 162
 163         // The command to be run
 164         execvp(my_argv[0], my_argv);
 165         fprintf(stderr, "execvp fails running %s (%d): %s\n", my_argv[0],
 166                 errno, strerror(errno));
 167         exit(-1);
 168 }
 169