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] [-v euid] [-j egid] [-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 "  -v euid              switch euid to UID\n"
  26 "  -j egid              switch egid to GID\n"
  27 "  -G[gid0,gid1,...]    set supplementary groups\n";
  28
  29 void Usage_and_abort(const char *name)
  30 {
  31         fprintf(stderr, usage, name);
  32         exit(-1);
  33 }
  34
  35 int main(int argc, char **argv)
  36 {
  37         char **my_argv, *name = argv[0], *grp;
  38         int status, c, i;
  39         int gid_is_set = 0, uid_is_set = 0, num_supp = -1;
  40         uid_t user_id = 0;
  41         gid_t grp_id = 0, supp_groups[NGROUPS_MAX] = { 0 };
  42         int euid_is_set = 0, egid_is_set = 0;
  43         uid_t euid = 0;
  44         gid_t egid = 0;
  45
  46         if (argc == 1) {
  47                 fprintf(stderr, "No parameter count\n");
  48                 Usage_and_abort(name);
  49         }
  50
  51         // get UID and GID
  52         while ((c = getopt(argc, argv, "+u:g:v:j:hG::")) != -1) {
  53                 switch (c) {
  54                 case 'u':
  55                         if (!isdigit(optarg[0])) {
  56                                 struct passwd *pw = getpwnam(optarg);
  57                                 if (pw == NULL) {
  58                                         fprintf(stderr, "parameter '%s' bad\n",
  59                                                 optarg);
  60                                         Usage_and_abort(name);
  61                                 }
  62                                 user_id = pw->pw_uid;
  63                         } else {
  64                                 user_id = (uid_t)atoi(optarg);
  65                         }
  66                         uid_is_set = 1;
  67                         if (!gid_is_set)
  68                                 grp_id = user_id;
  69                         break;
  70
  71                 case 'g':
  72                         if (!isdigit(optarg[0])) {
  73                                 struct group *gr = getgrnam(optarg);
  74                                 if (gr == NULL) {
  75                                         fprintf(stderr, "getgrname %s failed\n",
  76                                                 optarg);
  77                                         Usage_and_abort(name);
  78                                 }
  79                                 grp_id = gr->gr_gid;
  80                         } else {
  81                                 grp_id = (gid_t)atoi(optarg);
  82                         }
  83                         gid_is_set = 1;
  84                         break;
  85
  86                 case 'v':
  87                         if (!isdigit(optarg[0])) {
  88                                 struct passwd *pw = getpwnam(optarg);
  89                                 if (pw == NULL) {
  90                                         fprintf(stderr, "parameter '%s' bad\n",
  91                                                 optarg);
  92                                         Usage_and_abort(name);
  93                                 }
  94                                 euid = pw->pw_uid;
  95                         } else {
  96                                 euid = (uid_t)atoi(optarg);
  97                         }
  98                         euid_is_set = 1;
  99                         break;
 100
 101                 case 'j':
 102                         if (!isdigit(optarg[0])) {
 103                                 struct group *gr = getgrnam(optarg);
 104                                 if (gr == NULL) {
 105                                         fprintf(stderr, "getgrname %s failed\n",
 106                                                 optarg);
 107                                         Usage_and_abort(name);
 108                                 }
 109                                 egid = gr->gr_gid;
 110                         } else {
 111                                 egid = (gid_t)atoi(optarg);
 112                         }
 113                         egid_is_set = 1;
 114                         break;
 115
 116                 case 'G':
 117                         num_supp = 0;
 118                         if (optarg == NULL || !isdigit(optarg[0]))
 119                                 break;
 120                         while ((grp = strsep(&optarg, ",")) != NULL) {
 121                                 printf("adding supp group %d\n", atoi(grp));
 122                                 supp_groups[num_supp++] = atoi(grp);
 123                                 if (num_supp >= NGROUPS_MAX)
 124                                         break;
 125                         }
 126                         break;
 127
 128                 default:
 129                 case 'h':
 130                         Usage_and_abort(name);
 131                         break;
 132                 }
 133         }
 134
 135         if (!uid_is_set) {
 136                 fprintf(stderr, "Must specify uid to run.\n");
 137                 Usage_and_abort(name);
 138         }
 139
 140         if (optind == argc) {
 141                 fprintf(stderr, "Must specify command to run.\n");
 142                 Usage_and_abort(name);
 143         }
 144
 145         // assemble the command
 146         my_argv = (char**)malloc(sizeof(char*)*(argc+1-optind));
 147         if (my_argv == NULL) {
 148                 fprintf(stderr, "Error in allocating memory. (%s)\n",
 149                         strerror(errno));
 150                 exit(-1);
 151         }
 152
 153         for (i = optind; i < argc; i++) {
 154                 my_argv[i-optind] = argv[i];
 155                 //printf("%s\n",my_argv[i-optind]);
 156         }
 157         my_argv[i-optind] = NULL;
 158
 159 #if DEBUG
 160         system("whoami");
 161 #endif
 162
 163         // set GID
 164         if (!egid_is_set)
 165                 egid = grp_id;
 166         status = setregid(grp_id, egid);
 167         if (status == -1) {
 168                  fprintf(stderr, "Cannot change gid to %d/%d, errno=%d (%s)\n",
 169                          grp_id, egid, errno, strerror(errno) );
 170                  exit(-1);
 171         }
 172
 173         if (num_supp >= 0) {
 174                 status = setgroups(num_supp, supp_groups);
 175                 if (status == -1) {
 176                         perror("setting supplementary groups");
 177                         exit(-1);
 178                 }
 179         }
 180
 181         // set UID
 182         if (!euid_is_set)
 183                 euid = user_id;
 184         status = setreuid(user_id, euid);
 185         if(status == -1) {
 186                   fprintf(stderr,"Cannot change uid to %d/%d, errno=%d (%s)\n",
 187                            user_id, euid, errno, strerror(errno) );
 188                   exit(-1);
 189         }
 190
 191         fprintf(stderr, "running as uid/gid/euid/egid %d/%d/%d/%d, groups:",
 192                 user_id, grp_id, euid, egid);
 193         for (i = 0; i < num_supp; i++)
 194                 fprintf(stderr, " %d", supp_groups[i]);
 195         fprintf(stderr, "\n");
 196
 197         for (i = 0; i < argc - optind; i++)
 198                  fprintf(stderr, " [%s]", my_argv[i]);
 199
 200         fprintf(stderr, "\n");
 201         fflush(stderr);
 202
 203         // The command to be run
 204         execvp(my_argv[0], my_argv);
 205         fprintf(stderr, "execvp fails running %s (%d): %s\n", my_argv[0],
 206                 errno, strerror(errno));
 207         exit(-1);
 208 }
 209