examples/loadables/id.c

   1 /*
   2  * id - POSIX.2 user identity
   3  *
   4  * (INCOMPLETE -- supplementary groups for other users not yet done)
   5  *
   6  * usage: id [-Ggu] [-nr] [user]
   7  *
   8  * The default output format looks something like:
   9  *      uid=xxx(chet) gid=xx groups=aa(aname), bb(bname), cc(cname)
  10  */
  11
  12 /*
  13    Copyright (C) 1999-2009 Free Software Foundation, Inc.
  14
  15    This file is part of GNU Bash.
  16    Bash is free software: you can redistribute it and/or modify
  17    it under the terms of the GNU General Public License as published by
  18    the Free Software Foundation, either version 3 of the License, or
  19    (at your option) any later version.
  20
  21    Bash is distributed in the hope that it will be useful,
  22    but WITHOUT ANY WARRANTY; without even the implied warranty of
  23    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24    GNU General Public License for more details.
  25
  26    You should have received a copy of the GNU General Public License
  27    along with Bash.  If not, see <http://www.gnu.org/licenses/>.
  28 */
  29
  30 #include <config.h>
  31 #include <stdio.h>
  32 #include "bashtypes.h"
  33 #include <pwd.h>
  34 #include <grp.h>
  35 #include "bashansi.h"
  36
  37 #ifdef HAVE_LIMITS_H
  38 #  include <limits.h>
  39 #else
  40 #  include <sys/param.h>
  41 #endif
  42
  43 #if !defined (HAVE_GETPW_DECLS)
  44 extern struct passwd *getpwuid ();
  45 #endif
  46 extern struct group *getgrgid ();
  47
  48 #include "shell.h"
  49 #include "builtins.h"
  50 #include "stdc.h"
  51 #include "common.h"
  52 #include "bashgetopt.h"
  53
  54 #define ID_ALLGROUPS    0x001           /* -G */
  55 #define ID_GIDONLY      0x002           /* -g */
  56 #define ID_USENAME      0x004           /* -n */
  57 #define ID_USEREAL      0x008           /* -r */
  58 #define ID_USERONLY     0x010           /* -u */
  59
  60 #define ID_FLAGSET(s)   ((id_flags & (s)) != 0)
  61
  62 static int id_flags;
  63
  64 static uid_t ruid, euid;
  65 static gid_t rgid, egid;
  66
  67 static char *id_user;
  68
  69 static int inituser ();
  70
  71 static int id_pruser ();
  72 static int id_prgrp ();
  73 static int id_prgroups ();
  74 static int id_prall ();
  75
  76 int
  77 id_builtin (list)
  78      WORD_LIST *list;
  79 {
  80   int opt;
  81   char *user;
  82
  83   id_flags = 0;
  84   reset_internal_getopt ();
  85   while ((opt = internal_getopt (list, "Ggnru")) != -1)
  86     {
  87       switch (opt)
  88         {
  89         case 'G': id_flags |= ID_ALLGROUPS; break;
  90         case 'g': id_flags |= ID_GIDONLY; break;
  91         case 'n': id_flags |= ID_USENAME; break;
  92         case 'r': id_flags |= ID_USEREAL; break;
  93         case 'u': id_flags |= ID_USERONLY; break;
  94         default:
  95           builtin_usage ();
  96           return (EX_USAGE);
  97         }
  98     }
  99   list = loptend;
 100
 101   user = list ? list->word->word : (char *)NULL;
 102
 103   /* Check for some invalid option combinations */
 104   opt = ID_FLAGSET (ID_ALLGROUPS) + ID_FLAGSET (ID_GIDONLY) + ID_FLAGSET (ID_USERONLY);
 105   if (opt > 1 || (opt == 0 && ((id_flags & (ID_USEREAL|ID_USENAME)) != 0)))
 106     {
 107       builtin_usage ();
 108       return (EX_USAGE);
 109     }
 110
 111   if (list && list->next)
 112     {
 113       builtin_usage ();
 114       return (EX_USAGE);
 115     }
 116
 117   if (inituser (user) < 0)
 118     return (EXECUTION_FAILURE);
 119
 120   opt = 0;
 121   if (id_flags & ID_USERONLY)
 122     opt += id_pruser ((id_flags & ID_USEREAL) ? ruid : euid);
 123   else if (id_flags & ID_GIDONLY)
 124     opt += id_prgrp ((id_flags & ID_USEREAL) ? rgid : egid);
 125   else if (id_flags & ID_ALLGROUPS)
 126     opt += id_prgroups (user);
 127   else
 128     opt += id_prall (user);
 129   putchar ('\n');
 130   fflush (stdout);
 131
 132   return (opt == 0 ? EXECUTION_SUCCESS : EXECUTION_FAILURE);
 133 }
 134
 135 static int
 136 inituser (uname)
 137      char *uname;
 138 {
 139   struct passwd *pwd;
 140
 141   if (uname)
 142     {
 143       pwd = getpwnam (uname);
 144       if (pwd == 0)
 145         {
 146           builtin_error ("%s: no such user", uname);
 147           return -1;
 148         }
 149       ruid = euid = pwd->pw_uid;
 150       rgid = egid = pwd->pw_gid;
 151     }
 152   else
 153     {
 154       ruid = current_user.uid;
 155       euid = current_user.euid;
 156       rgid = current_user.gid;
 157       egid = current_user.egid;
 158     }
 159   return 0;
 160 }
 161
 162 /* Print the name or value of user ID UID. */
 163 static int
 164 id_pruser (uid)
 165      int uid;
 166 {
 167   struct passwd *pwd = NULL;
 168   int r;
 169
 170   r = 0;
 171   if (id_flags & ID_USENAME)
 172     {
 173       pwd = getpwuid (uid);
 174       if (pwd == NULL)
 175         r = 1;
 176     }
 177   if (pwd)
 178     printf ("%s", pwd->pw_name);
 179   else
 180     printf ("%u", (unsigned) uid);
 181
 182   return r;
 183 }
 184
 185 /* Print the name or value of group ID GID. */
 186
 187 static int
 188 id_prgrp (gid)
 189      int gid;
 190 {
 191   struct group *grp = NULL;
 192   int r;
 193
 194   r = 0;
 195   if (id_flags & ID_USENAME)
 196     {
 197       grp = getgrgid (gid);
 198       if (grp == NULL)
 199         r = 1;
 200     }
 201
 202   if (grp)
 203     printf ("%s", grp->gr_name);
 204   else
 205     printf ("%u", (unsigned) gid);
 206
 207   return r;
 208 }
 209
 210 static int
 211 id_prgroups (uname)
 212      char *uname;
 213 {
 214   int *glist, ng, i, r;
 215
 216   r = 0;
 217   id_prgrp (rgid);
 218   if (egid != rgid)
 219     {
 220       putchar (' ');
 221       id_prgrp (egid);
 222     }
 223
 224   if (uname)
 225     {
 226       builtin_error ("supplementary groups for other users not yet implemented");
 227       glist = (int *)NULL;
 228       ng = 0;
 229       r = 1;
 230     }
 231   else
 232     glist = get_group_array (&ng);
 233
 234   for (i = 0; i < ng; i++)
 235     if (glist[i] != rgid && glist[i] != egid)
 236       {
 237         putchar (' ');
 238         id_prgrp (glist[i]);
 239       }
 240
 241   return r;
 242 }
 243
 244 static int
 245 id_prall (uname)
 246      char *uname;
 247 {
 248   int r, i, ng, *glist;
 249   struct passwd *pwd;
 250   struct group *grp;
 251
 252   r = 0;
 253   printf ("uid=%u", (unsigned) ruid);
 254   pwd = getpwuid (ruid);
 255   if (pwd == NULL)
 256     r = 1;
 257   else
 258     printf ("(%s)", pwd->pw_name);
 259
 260   printf (" gid=%u", (unsigned) rgid);
 261   grp = getgrgid (rgid);
 262   if (grp == NULL)
 263     r = 1;
 264   else
 265     printf ("(%s)", grp->gr_name);
 266
 267   if (euid != ruid)
 268     {
 269       printf (" euid=%u", (unsigned) euid);
 270       pwd = getpwuid (euid);
 271       if (pwd == NULL)
 272         r = 1;
 273       else
 274         printf ("(%s)", pwd->pw_name);
 275     }
 276
 277   if (egid != rgid)
 278     {
 279       printf (" egid=%u", (unsigned) egid);
 280       grp = getgrgid (egid);
 281       if (grp == NULL)
 282         r = 1;
 283       else
 284         printf ("(%s)", grp->gr_name);
 285     }
 286
 287   if (uname)
 288     {
 289       builtin_error ("supplementary groups for other users not yet implemented");
 290       glist = (int *)NULL;
 291       ng = 0;
 292       r = 1;
 293     }
 294   else
 295     glist = get_group_array (&ng);
 296
 297   if (ng > 0)
 298     printf (" groups=");
 299   for (i = 0; i < ng; i++)
 300     {
 301       if (i > 0)
 302         printf (", ");
 303       printf ("%u", (unsigned) glist[i]);
 304       grp = getgrgid (glist[i]);
 305       if (grp == NULL)
 306         r = 1;
 307       else
 308         printf ("(%s)", grp->gr_name);
 309     }
 310
 311   return r;
 312 }
 313
 314 char *id_doc[] = {
 315         "Display information about user."
 316         "",
 317         "Return information about user identity",
 318         (char *)NULL
 319 };
 320
 321 struct builtin id_struct = {
 322         "id",
 323         id_builtin,
 324         BUILTIN_ENABLED,
 325         id_doc,
 326         "id [user]\n\tid -G [-n] [user]\n\tid -g [-nr] [user]\n\tid -u [-nr] [user]",
 327         0
 328 };