release/src/router/busybox/coreutils/id.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini id implementation for busybox
   4  *
   5  * Copyright (C) 2000 by Randolph Chung <tausq@debian.org>
   6  * Copyright (C) 2008 by Tito Ragusa <farmatito@tiscali.it>
   7  *
   8  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   9  */
  10
  11 /* BB_AUDIT SUSv3 compliant. */
  12 /* Hacked by Tito Ragusa (C) 2004 to handle usernames of whatever
  13  * length and to be more similar to GNU id.
  14  * -Z option support: by Yuichi Nakamura <ynakam@hitachisoft.jp>
  15  * Added -G option Tito Ragusa (C) 2008 for SUSv3.
  16  */
  17
  18 #include "libbb.h"
  19
  20 /* This is a NOEXEC applet. Be very careful! */
  21
  22 #if !ENABLE_USE_BB_PWD_GRP
  23 #if defined(__UCLIBC_MAJOR__) && (__UCLIBC_MAJOR__ == 0)
  24 #if (__UCLIBC_MINOR__ < 9) || (__UCLIBC_MINOR__ == 9 &&  __UCLIBC_SUBLEVEL__ < 30)
  25 #error "Sorry, you need at least uClibc version 0.9.30 for id applet to build"
  26 #endif
  27 #endif
  28 #endif
  29
  30 enum {
  31         PRINT_REAL      = (1 << 0),
  32         NAME_NOT_NUMBER = (1 << 1),
  33         JUST_USER       = (1 << 2),
  34         JUST_GROUP      = (1 << 3),
  35         JUST_ALL_GROUPS = (1 << 4),
  36 #if ENABLE_SELINUX
  37         JUST_CONTEXT    = (1 << 5),
  38 #endif
  39 };
  40
  41 static int print_common(unsigned id, const char *name, const char *prefix)
  42 {
  43         if (prefix) {
  44                 printf("%s", prefix);
  45         }
  46         if (!(option_mask32 & NAME_NOT_NUMBER) || !name) {
  47                 printf("%u", id);
  48         }
  49         if (!option_mask32 || (option_mask32 & NAME_NOT_NUMBER)) {
  50                 if (name) {
  51                         printf(option_mask32 ? "%s" : "(%s)", name);
  52                 } else {
  53                         /* Don't set error status flag in default mode */
  54                         if (option_mask32) {
  55                                 if (ENABLE_DESKTOP)
  56                                         bb_error_msg("unknown ID %u", id);
  57                                 return EXIT_FAILURE;
  58                         }
  59                 }
  60         }
  61         return EXIT_SUCCESS;
  62 }
  63
  64 static int print_group(gid_t id, const char *prefix)
  65 {
  66         return print_common(id, gid2group(id), prefix);
  67 }
  68
  69 static int print_user(uid_t id, const char *prefix)
  70 {
  71         return print_common(id, uid2uname(id), prefix);
  72 }
  73
  74 /* On error set *n < 0 and return >= 0
  75  * If *n is too small, update it and return < 0
  76  *  (ok to trash groups[] in both cases)
  77  * Otherwise fill in groups[] and return >= 0
  78  */
  79 static int get_groups(const char *username, gid_t rgid, gid_t *groups, int *n)
  80 {
  81         int m;
  82
  83         if (username) {
  84                 /* If the user is a member of more than
  85                  * *n groups, then -1 is returned. Otherwise >= 0.
  86                  * (and no defined way of detecting errors?!) */
  87                 m = getgrouplist(username, rgid, groups, n);
  88                 /* I guess *n < 0 might indicate error. Anyway,
  89                  * malloc'ing -1 bytes won't be good, so: */
  90                 //if (*n < 0)
  91                 //      return 0;
  92                 //return m;
  93                 //commented out here, happens below anyway
  94         } else {
  95                 /* On error -1 is returned, which ends up in *n */
  96                 int nn = getgroups(*n, groups);
  97                 /* 0: nn <= *n, groups[] was big enough; -1 otherwise */
  98                 m = - (nn > *n);
  99                 *n = nn;
 100         }
 101         if (*n < 0)
 102                 return 0; /* error, don't return < 0! */
 103         return m;
 104 }
 105
 106 int id_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 107 int id_main(int argc UNUSED_PARAM, char **argv)
 108 {
 109         uid_t ruid;
 110         gid_t rgid;
 111         uid_t euid;
 112         gid_t egid;
 113         unsigned opt;
 114         int i;
 115         int status = EXIT_SUCCESS;
 116         const char *prefix;
 117         const char *username;
 118 #if ENABLE_SELINUX
 119         security_context_t scontext = NULL;
 120 #endif
 121         /* Don't allow -n -r -nr -ug -rug -nug -rnug -uZ -gZ -GZ*/
 122         /* Don't allow more than one username */
 123         opt_complementary = "?1:u--g:g--u:G--u:u--G:g--G:G--g:r?ugG:n?ugG"
 124                          IF_SELINUX(":u--Z:Z--u:g--Z:Z--g:G--Z:Z--G");
 125         opt = getopt32(argv, "rnugG" IF_SELINUX("Z"));
 126
 127         username = argv[optind];
 128         if (username) {
 129                 struct passwd *p = xgetpwnam(username);
 130                 euid = ruid = p->pw_uid;
 131                 egid = rgid = p->pw_gid;
 132         } else {
 133                 egid = getegid();
 134                 rgid = getgid();
 135                 euid = geteuid();
 136                 ruid = getuid();
 137         }
 138         /* JUST_ALL_GROUPS ignores -r PRINT_REAL flag even if man page for */
 139         /* id says: print the real ID instead of the effective ID, with -ugG */
 140         /* in fact in this case egid is always printed if egid != rgid */
 141         if (!opt || (opt & JUST_ALL_GROUPS)) {
 142                 gid_t *groups;
 143                 int n;
 144
 145                 if (!opt) {
 146                         /* Default Mode */
 147                         status |= print_user(ruid, "uid=");
 148                         status |= print_group(rgid, " gid=");
 149                         if (euid != ruid)
 150                                 status |= print_user(euid, " euid=");
 151                         if (egid != rgid)
 152                                 status |= print_group(egid, " egid=");
 153                 } else {
 154                         /* JUST_ALL_GROUPS */
 155                         status |= print_group(rgid, NULL);
 156                         if (egid != rgid)
 157                                 status |= print_group(egid, " ");
 158                 }
 159                 /* We are supplying largish buffer, trying
 160                  * to not run get_groups() twice. That might be slow
 161                  * ("user database in remote SQL server" case) */
 162                 groups = xmalloc(64 * sizeof(gid_t));
 163                 n = 64;
 164                 if (get_groups(username, rgid, groups, &n) < 0) {
 165                         /* Need bigger buffer after all */
 166                         groups = xrealloc(groups, n * sizeof(gid_t));
 167                         get_groups(username, rgid, groups, &n);
 168                 }
 169                 if (n > 0) {
 170                         /* Print the list */
 171                         prefix = " groups=";
 172                         for (i = 0; i < n; i++) {
 173                                 if (opt && (groups[i] == rgid || groups[i] == egid))
 174                                         continue;
 175                                 status |= print_group(groups[i], opt ? " " : prefix);
 176                                 prefix = ",";
 177                         }
 178                 } else if (n < 0) { /* error in get_groups() */
 179                         if (!ENABLE_DESKTOP)
 180                                 bb_error_msg_and_die("can't get groups");
 181                         else
 182                                 return EXIT_FAILURE;
 183                 }
 184                 if (ENABLE_FEATURE_CLEAN_UP)
 185                         free(groups);
 186 #if ENABLE_SELINUX
 187                 if (is_selinux_enabled()) {
 188                         if (getcon(&scontext) == 0)
 189                                 printf(" context=%s", scontext);
 190                 }
 191 #endif
 192         } else if (opt & PRINT_REAL) {
 193                 euid = ruid;
 194                 egid = rgid;
 195         }
 196
 197         if (opt & JUST_USER)
 198                 status |= print_user(euid, NULL);
 199         else if (opt & JUST_GROUP)
 200                 status |= print_group(egid, NULL);
 201 #if ENABLE_SELINUX
 202         else if (opt & JUST_CONTEXT) {
 203                 selinux_or_die();
 204                 if (username || getcon(&scontext)) {
 205                         bb_error_msg_and_die("can't get process context%s",
 206                                 username ? " for a different user" : "");
 207                 }
 208                 fputs(scontext, stdout);
 209         }
 210         /* freecon(NULL) seems to be harmless */
 211         if (ENABLE_FEATURE_CLEAN_UP)
 212                 freecon(scontext);
 213 #endif
 214         bb_putchar('\n');
 215         fflush_stdout_and_exit(status);
 216 }