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 #include <config.h>
  13 #include <stdio.h>
  14 #include "bashtypes.h"
  15 #include <pwd.h>
  16 #include <grp.h>
  17 #include "bashansi.h"
  18
  19 #ifdef HAVE_LIMITS_H
  20 #  include <limits.h>
  21 #else
  22 #  include <sys/param.h>
  23 #endif
  24
  25 #if !defined (HAVE_GETPW_DECLS)
  26 extern struct passwd *getpwuid ();
  27 #endif
  28 extern struct group *getgrgid ();
  29
  30 #include "shell.h"
  31 #include "builtins.h"
  32 #include "stdc.h"
  33 #include "common.h"
  34 #include "bashgetopt.h"
  35
  36 #define ID_ALLGROUPS    0x001           /* -G */
  37 #define ID_GIDONLY      0x002           /* -g */
  38 #define ID_USENAME      0x004           /* -n */
  39 #define ID_USEREAL      0x008           /* -r */
  40 #define ID_USERONLY     0x010           /* -u */
  41
  42 #define ID_FLAGSET(s)   ((id_flags & (s)) != 0)
  43
  44 static int id_flags;
  45
  46 static uid_t ruid, euid;
  47 static gid_t rgid, egid;
  48
  49 static char *id_user;
  50
  51 static int inituser ();
  52
  53 static int id_pruser ();
  54 static int id_prgrp ();
  55 static int id_prgroups ();
  56 static int id_prall ();
  57
  58 int
  59 id_builtin (list)
  60      WORD_LIST *list;
  61 {
  62   int opt;
  63   char *user;
  64
  65   id_flags = 0;
  66   reset_internal_getopt ();
  67   while ((opt = internal_getopt (list, "Ggnru")) != -1)
  68     {
  69       switch (opt)
  70         {
  71         case 'G': id_flags |= ID_ALLGROUPS; break;
  72         case 'g': id_flags |= ID_GIDONLY; break;
  73         case 'n': id_flags |= ID_USENAME; break;
  74         case 'r': id_flags |= ID_USEREAL; break;
  75         case 'u': id_flags |= ID_USERONLY; break;
  76         default:
  77           builtin_usage ();
  78           return (EX_USAGE);
  79         }
  80     }
  81   list = loptend;
  82
  83   user = list ? list->word->word : (char *)NULL;
  84
  85   /* Check for some invalid option combinations */
  86   opt = ID_FLAGSET (ID_ALLGROUPS) + ID_FLAGSET (ID_GIDONLY) + ID_FLAGSET (ID_USERONLY);
  87   if (opt > 1 || (opt == 0 && ((id_flags & (ID_USEREAL|ID_USENAME)) != 0)))
  88     {
  89       builtin_usage ();
  90       return (EX_USAGE);
  91     }
  92
  93   if (list && list->next)
  94     {
  95       builtin_usage ();
  96       return (EX_USAGE);
  97     }
  98
  99   if (inituser (user) < 0)
 100     return (EXECUTION_FAILURE);
 101
 102   opt = 0;
 103   if (id_flags & ID_USERONLY)
 104     opt += id_pruser ((id_flags & ID_USEREAL) ? ruid : euid);
 105   else if (id_flags & ID_GIDONLY)
 106     opt += id_prgrp ((id_flags & ID_USEREAL) ? rgid : egid);
 107   else if (id_flags & ID_ALLGROUPS)
 108     opt += id_prgroups (user);
 109   else
 110     opt += id_prall (user);
 111   putchar ('\n');
 112   fflush (stdout);
 113
 114   return (opt == 0 ? EXECUTION_SUCCESS : EXECUTION_FAILURE);
 115 }
 116
 117 static int
 118 inituser (uname)
 119      char *uname;
 120 {
 121   struct passwd *pwd;
 122
 123   if (uname)
 124     {
 125       pwd = getpwnam (uname);
 126       if (pwd == 0)
 127         {
 128           builtin_error ("%s: no such user", uname);
 129           return -1;
 130         }
 131       ruid = euid = pwd->pw_uid;
 132       rgid = egid = pwd->pw_gid;
 133     }
 134   else
 135     {
 136       ruid = current_user.uid;
 137       euid = current_user.euid;
 138       rgid = current_user.gid;
 139       egid = current_user.egid;
 140     }
 141   return 0;
 142 }
 143
 144 /* Print the name or value of user ID UID. */
 145 static int
 146 id_pruser (uid)
 147      int uid;
 148 {
 149   struct passwd *pwd = NULL;
 150   int r;
 151
 152   r = 0;
 153   if (id_flags & ID_USENAME)
 154     {
 155       pwd = getpwuid (uid);
 156       if (pwd == NULL)
 157         r = 1;
 158     }
 159   if (pwd)
 160     printf ("%s", pwd->pw_name);
 161   else
 162     printf ("%u", (unsigned) uid);
 163
 164   return r;
 165 }
 166
 167 /* Print the name or value of group ID GID. */
 168
 169 static int
 170 id_prgrp (gid)
 171      int gid;
 172 {
 173   struct group *grp = NULL;
 174   int r;
 175
 176   r = 0;
 177   if (id_flags & ID_USENAME)
 178     {
 179       grp = getgrgid (gid);
 180       if (grp == NULL)
 181         r = 1;
 182     }
 183
 184   if (grp)
 185     printf ("%s", grp->gr_name);
 186   else
 187     printf ("%u", (unsigned) gid);
 188
 189   return r;
 190 }
 191
 192 static int
 193 id_prgroups (uname)
 194      char *uname;
 195 {
 196   int *glist, ng, i, r;
 197
 198   r = 0;
 199   id_prgrp (rgid);
 200   if (egid != rgid)
 201     {
 202       putchar (' ');
 203       id_prgrp (egid);
 204     }
 205
 206   if (uname)
 207     {
 208       builtin_error ("supplementary groups for other users not yet implemented");
 209       glist = (int *)NULL;
 210       ng = 0;
 211       r = 1;
 212     }
 213   else
 214     glist = get_group_array (&ng);
 215
 216   for (i = 0; i < ng; i++)
 217     if (glist[i] != rgid && glist[i] != egid)
 218       {
 219         putchar (' ');
 220         id_prgrp (glist[i]);
 221       }
 222
 223   return r;
 224 }
 225
 226 static int
 227 id_prall (uname)
 228      char *uname;
 229 {
 230   int r, i, ng, *glist;
 231   struct passwd *pwd;
 232   struct group *grp;
 233
 234   r = 0;
 235   printf ("uid=%u", (unsigned) ruid);
 236   pwd = getpwuid (ruid);
 237   if (pwd == NULL)
 238     r = 1;
 239   else
 240     printf ("(%s)", pwd->pw_name);
 241
 242   printf (" gid=%u", (unsigned) rgid);
 243   grp = getgrgid (rgid);
 244   if (grp == NULL)
 245     r = 1;
 246   else
 247     printf ("(%s)", grp->gr_name);
 248
 249   if (euid != ruid)
 250     {
 251       printf (" euid=%u", (unsigned) euid);
 252       pwd = getpwuid (euid);
 253       if (pwd == NULL)
 254         r = 1;
 255       else
 256         printf ("(%s)", pwd->pw_name);
 257     }
 258
 259   if (egid != rgid)
 260     {
 261       printf (" egid=%u", (unsigned) egid);
 262       grp = getgrgid (egid);
 263       if (grp == NULL)
 264         r = 1;
 265       else
 266         printf ("(%s)", grp->gr_name);
 267     }
 268
 269   if (uname)
 270     {
 271       builtin_error ("supplementary groups for other users not yet implemented");
 272       glist = (int *)NULL;
 273       ng = 0;
 274       r = 1;
 275     }
 276   else
 277     glist = get_group_array (&ng);
 278
 279   if (ng > 0)
 280     printf (" groups=");
 281   for (i = 0; i < ng; i++)
 282     {
 283       if (i > 0)
 284         printf (", ");
 285       printf ("%u", (unsigned) glist[i]);
 286       grp = getgrgid (glist[i]);
 287       if (grp == NULL)
 288         r = 1;
 289       else
 290         printf ("(%s)", grp->gr_name);
 291     }
 292
 293   return r;
 294 }
 295
 296 char *id_doc[] = {
 297         "return information about user identity",
 298         (char *)NULL
 299 };
 300
 301 struct builtin id_struct = {
 302         "id",
 303         id_builtin,
 304         BUILTIN_ENABLED,
 305         id_doc,
 306         "id [user]\n\tid -G [-n] [user]\n\tid -g [-nr] [user]\n\tid -u [-nr] [user]",
 307         0
 308 };