uidlist.c

   1 /*
   2    Copyright (C) Andrew Tridgell 1996
   3    Copyright (C) Paul Mackerras 1996
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20 /* handle the mapping of uid/gid and user/group names between systems.
  21    If the source username/group does not exist on the target then use
  22    the numeric IDs. Never do any mapping for uid=0 or gid=0 as these
  23    are special.
  24 */
  25
  26 #include "rsync.h"
  27
  28 #ifdef HAVE_GETGROUPS
  29 # ifndef GETGROUPS_T
  30 #  define GETGROUPS_T gid_t
  31 # endif
  32 #endif
  33
  34 extern int verbose;
  35 extern int preserve_uid;
  36 extern int preserve_gid;
  37 extern int numeric_ids;
  38 extern int am_root;
  39
  40 struct idlist {
  41         struct idlist *next;
  42         int id, id2;
  43         char *name;
  44 };
  45
  46 static struct idlist *uidlist;
  47 static struct idlist *gidlist;
  48
  49 static struct idlist *add_to_list(struct idlist **root, int id, char *name,
  50                                   int id2)
  51 {
  52         struct idlist *node = new(struct idlist);
  53         if (!node)
  54                 out_of_memory("add_to_list");
  55         node->next = *root;
  56         node->name = name;
  57         node->id = id;
  58         node->id2 = id2;
  59         *root = node;
  60         return node;
  61 }
  62
  63 /* turn a uid into a user name */
  64 static char *uid_to_name(uid_t uid)
  65 {
  66         struct passwd *pass = getpwuid(uid);
  67         if (pass)
  68                 return strdup(pass->pw_name);
  69         return NULL;
  70 }
  71
  72 /* turn a gid into a group name */
  73 static char *gid_to_name(gid_t gid)
  74 {
  75         struct group *grp = getgrgid(gid);
  76         if (grp)
  77                 return strdup(grp->gr_name);
  78         return NULL;
  79 }
  80
  81 static int map_uid(int id, char *name)
  82 {
  83         uid_t uid;
  84         if (id != 0 && name_to_uid(name, &uid))
  85                 return uid;
  86         return id;
  87 }
  88
  89 static int map_gid(int id, char *name)
  90 {
  91         gid_t gid;
  92         if (id != 0 && name_to_gid(name, &gid))
  93                 return gid;
  94         return id;
  95 }
  96
  97 static int is_in_group(gid_t gid)
  98 {
  99 #ifdef HAVE_GETGROUPS
 100         static gid_t last_in = GID_NONE, last_out;
 101         static int ngroups = -2;
 102         static GETGROUPS_T *gidset;
 103         int n;
 104
 105         if (gid == last_in)
 106                 return last_out;
 107         if (ngroups < -1) {
 108                 gid_t mygid = MY_GID();
 109                 if ((ngroups = getgroups(0, NULL)) < 0)
 110                         ngroups = 0;
 111                 gidset = new_array(GETGROUPS_T, ngroups+1);
 112                 if (!gidset)
 113                         out_of_memory("is_in_group");
 114                 if (ngroups > 0)
 115                         ngroups = getgroups(ngroups, gidset);
 116                 /* The default gid might not be in the list on some systems. */
 117                 for (n = 0; n < ngroups; n++) {
 118                         if (gidset[n] == mygid)
 119                                 break;
 120                 }
 121                 if (n == ngroups)
 122                         gidset[ngroups++] = mygid;
 123                 if (verbose > 3) {
 124                         int pos;
 125                         char *gidbuf = new_array(char, ngroups*21+32);
 126                         if (!gidbuf)
 127                                 out_of_memory("is_in_group");
 128                         sprintf(gidbuf, "process has %d gid%s: ",
 129                             ngroups, ngroups == 1? "" : "s");
 130                         pos = strlen(gidbuf);
 131                         for (n = 0; n < ngroups; n++) {
 132                                 sprintf(gidbuf+pos, " %d", (int)gidset[n]);
 133                                 pos += strlen(gidbuf+pos);
 134                         }
 135                         rprintf(FINFO, "%s\n", gidbuf);
 136                         free(gidbuf);
 137                 }
 138         }
 139
 140         last_in = gid;
 141         for (n = 0; n < ngroups; n++) {
 142                 if (gidset[n] == gid)
 143                         return last_out = 1;
 144         }
 145         return last_out = 0;
 146
 147 #else
 148         static gid_t mygid = GID_NONE;
 149         if (mygid == GID_NONE) {
 150                 mygid = MY_GID();
 151                 if (verbose > 3)
 152                         rprintf(FINFO, "process has gid %d\n", (int)mygid);
 153         }
 154         return gid == mygid;
 155 #endif
 156 }
 157
 158 /* Add a uid to the list of uids.  Only called on receiving side. */
 159 static struct idlist *recv_add_uid(int id, char *name)
 160 {
 161         int id2 = name ? map_uid(id, name) : id;
 162         struct idlist *node;
 163
 164         node = add_to_list(&uidlist, id, name, id2);
 165
 166         if (verbose > 3) {
 167                 rprintf(FINFO, "uid %d(%s) maps to %d\n",
 168                     id, name ? name : "", id2);
 169         }
 170
 171         return node;
 172 }
 173
 174 /* Add a gid to the list of gids.  Only called on receiving side. */
 175 static struct idlist *recv_add_gid(int id, char *name)
 176 {
 177         int id2 = name ? map_gid(id, name) : id;
 178         struct idlist *node;
 179
 180         if (!am_root && !is_in_group(id2))
 181                 id2 = GID_NONE;
 182         node = add_to_list(&gidlist, id, name, id2);
 183
 184         if (verbose > 3) {
 185                 rprintf(FINFO, "gid %d(%s) maps to %d\n",
 186                     id, name ? name : "", id2);
 187         }
 188
 189         return node;
 190 }
 191
 192 /* this function is a definate candidate for a faster algorithm */
 193 static uid_t match_uid(uid_t uid)
 194 {
 195         static uid_t last_in, last_out;
 196         struct idlist *list;
 197
 198         if (uid == 0)
 199                 return 0;
 200
 201         if (uid == last_in)
 202                 return last_out;
 203
 204         last_in = uid;
 205
 206         for (list = uidlist; list; list = list->next) {
 207                 if (list->id == (int)uid)
 208                         return last_out = (uid_t)list->id2;
 209         }
 210
 211         return last_out = uid;
 212 }
 213
 214 static gid_t match_gid(gid_t gid)
 215 {
 216         static gid_t last_in = GID_NONE, last_out = GID_NONE;
 217         struct idlist *list;
 218
 219         if (gid == GID_NONE)
 220                 return GID_NONE;
 221
 222         if (gid == last_in)
 223                 return last_out;
 224
 225         last_in = gid;
 226
 227         for (list = gidlist; list; list = list->next) {
 228                 if (list->id == (int)gid)
 229                         return last_out = (gid_t)list->id2;
 230         }
 231
 232         list = recv_add_gid(gid, NULL);
 233         return last_out = list->id2;
 234 }
 235
 236 /* Add a uid to the list of uids.  Only called on sending side. */
 237 void add_uid(uid_t uid)
 238 {
 239         struct idlist *list;
 240
 241         if (uid == 0)   /* don't map root */
 242                 return;
 243
 244         for (list = uidlist; list; list = list->next) {
 245                 if (list->id == (int)uid)
 246                         return;
 247         }
 248
 249         add_to_list(&uidlist, (int)uid, uid_to_name(uid), 0);
 250 }
 251
 252 /* Add a gid to the list of gids.  Only called on sending side. */
 253 void add_gid(gid_t gid)
 254 {
 255         struct idlist *list;
 256
 257         if (gid == 0)   /* don't map root */
 258                 return;
 259
 260         for (list = gidlist; list; list = list->next) {
 261                 if (list->id == (int)gid)
 262                         return;
 263         }
 264
 265         add_to_list(&gidlist, (int)gid, gid_to_name(gid), 0);
 266 }
 267
 268
 269 /* send a complete uid/gid mapping to the peer */
 270 void send_uid_list(int f)
 271 {
 272         struct idlist *list;
 273
 274         if (numeric_ids)
 275                 return;
 276
 277         if (preserve_uid) {
 278                 int len;
 279                 /* we send sequences of uid/byte-length/name */
 280                 for (list = uidlist; list; list = list->next) {
 281                         if (!list->name)
 282                                 continue;
 283                         len = strlen(list->name);
 284                         write_int(f, list->id);
 285                         write_byte(f, len);
 286                         write_buf(f, list->name, len);
 287                 }
 288
 289                 /* terminate the uid list with a 0 uid. We explicitly exclude
 290                  * 0 from the list */
 291                 write_int(f, 0);
 292         }
 293
 294         if (preserve_gid) {
 295                 int len;
 296                 for (list = gidlist; list; list = list->next) {
 297                         if (!list->name)
 298                                 continue;
 299                         len = strlen(list->name);
 300                         write_int(f, list->id);
 301                         write_byte(f, len);
 302                         write_buf(f, list->name, len);
 303                 }
 304                 write_int(f, 0);
 305         }
 306 }
 307
 308 /* recv a complete uid/gid mapping from the peer and map the uid/gid
 309  * in the file list to local names */
 310 void recv_uid_list(int f, struct file_list *flist)
 311 {
 312         int id, i;
 313         char *name;
 314
 315         if (preserve_uid && !numeric_ids) {
 316                 /* read the uid list */
 317                 while ((id = read_int(f)) != 0) {
 318                         int len = read_byte(f);
 319                         name = new_array(char, len+1);
 320                         if (!name)
 321                                 out_of_memory("recv_uid_list");
 322                         read_sbuf(f, name, len);
 323                         recv_add_uid(id, name); /* node keeps name's memory */
 324                 }
 325         }
 326
 327
 328         if (preserve_gid && !numeric_ids) {
 329                 /* read the gid list */
 330                 while ((id = read_int(f)) != 0) {
 331                         int len = read_byte(f);
 332                         name = new_array(char, len+1);
 333                         if (!name)
 334                                 out_of_memory("recv_uid_list");
 335                         read_sbuf(f, name, len);
 336                         recv_add_gid(id, name); /* node keeps name's memory */
 337                 }
 338         }
 339
 340         /* now convert the uid/gid of all files in the list to the mapped
 341          * uid/gid */
 342         if (am_root && preserve_uid && !numeric_ids) {
 343                 for (i = 0; i < flist->count; i++)
 344                         flist->files[i]->uid = match_uid(flist->files[i]->uid);
 345         }
 346         if (preserve_gid && (!am_root || !numeric_ids)) {
 347                 for (i = 0; i < flist->count; i++)
 348                         flist->files[i]->gid = match_gid(flist->files[i]->gid);
 349         }
 350 }