libexec/revnetgroup/parse_netgroup.c

   1 /*
   2  * Copyright (c) 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Rick Macklem at The University of Guelph.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * $FreeBSD: src/libexec/revnetgroup/parse_netgroup.c,v 1.7 1999/08/28 00:09:48 peter Exp $
  37  * $DragonFly: src/libexec/revnetgroup/parse_netgroup.c,v 1.3 2004/08/25 01:53:39 dillon Exp $
  38  */
  39
  40 /*
  41  * This is a specially hacked-up version of getnetgrent.c used to parse
  42  * data from the stored hash table of netgroup info rather than from a
  43  * file. It's used mainly for the parse_netgroup() function. All the YP
  44  * stuff and file support has been stripped out since it isn't needed.
  45  */
  46
  47 #include <stdio.h>
  48 #include <strings.h>
  49 #include <stdlib.h>
  50 #include <unistd.h>
  51 #include "hash.h"
  52
  53 /*
  54  * Static Variables and functions used by setnetgrent(), getnetgrent() and
  55  * __endnetgrent().
  56  * There are two linked lists:
  57  * - linelist is just used by setnetgrent() to parse the net group file via.
  58  *   parse_netgrp()
  59  * - netgrp is the list of entries for the current netgroup
  60  */
  61 struct linelist {
  62         struct linelist *l_next;        /* Chain ptr. */
  63         int             l_parsed;       /* Flag for cycles */
  64         char            *l_groupname;   /* Name of netgroup */
  65         char            *l_line;        /* Netgroup entrie(s) to be parsed */
  66 };
  67
  68 struct netgrp {
  69         struct netgrp   *ng_next;       /* Chain ptr */
  70         char            *ng_str[3];     /* Field pointers, see below */
  71 };
  72 #define NG_HOST         0       /* Host name */
  73 #define NG_USER         1       /* User name */
  74 #define NG_DOM          2       /* and Domain name */
  75
  76 static struct linelist  *linehead = (struct linelist *)0;
  77 static struct netgrp    *nextgrp = (struct netgrp *)0;
  78 static struct {
  79         struct netgrp   *gr;
  80         char            *grname;
  81 } grouphead = {
  82         (struct netgrp *)0,
  83         (char *)0,
  84 };
  85 static int parse_netgrp();
  86 static struct linelist *read_for_group();
  87 void __setnetgrent(), __endnetgrent();
  88 int __getnetgrent();
  89 extern struct group_entry *gtable[];
  90
  91 /*
  92  * setnetgrent()
  93  * Parse the netgroup file looking for the netgroup and build the list
  94  * of netgrp structures. Let parse_netgrp() and read_for_group() do
  95  * most of the work.
  96  */
  97 void
  98 __setnetgrent(group)
  99         char *group;
 100 {
 101         /* Sanity check */
 102
 103         if (group == NULL || !strlen(group))
 104                 return;
 105
 106         if (grouphead.gr == (struct netgrp *)0 ||
 107                 strcmp(group, grouphead.grname)) {
 108                 __endnetgrent();
 109                 if (parse_netgrp(group))
 110                         __endnetgrent();
 111                 else {
 112                         grouphead.grname = (char *)
 113                                 malloc(strlen(group) + 1);
 114                         strcpy(grouphead.grname, group);
 115                 }
 116         }
 117         nextgrp = grouphead.gr;
 118 }
 119
 120 /*
 121  * Get the next netgroup off the list.
 122  */
 123 int
 124 __getnetgrent(hostp, userp, domp)
 125         char **hostp, **userp, **domp;
 126 {
 127         if (nextgrp) {
 128                 *hostp = nextgrp->ng_str[NG_HOST];
 129                 *userp = nextgrp->ng_str[NG_USER];
 130                 *domp = nextgrp->ng_str[NG_DOM];
 131                 nextgrp = nextgrp->ng_next;
 132                 return (1);
 133         }
 134         return (0);
 135 }
 136
 137 /*
 138  * __endnetgrent() - cleanup
 139  */
 140 void
 141 __endnetgrent()
 142 {
 143         register struct linelist *lp, *olp;
 144         register struct netgrp *gp, *ogp;
 145
 146         lp = linehead;
 147         while (lp) {
 148                 olp = lp;
 149                 lp = lp->l_next;
 150                 free(olp->l_groupname);
 151                 free(olp->l_line);
 152                 free((char *)olp);
 153         }
 154         linehead = (struct linelist *)0;
 155         if (grouphead.grname) {
 156                 free(grouphead.grname);
 157                 grouphead.grname = (char *)0;
 158         }
 159         gp = grouphead.gr;
 160         while (gp) {
 161                 ogp = gp;
 162                 gp = gp->ng_next;
 163                 if (ogp->ng_str[NG_HOST])
 164                         free(ogp->ng_str[NG_HOST]);
 165                 if (ogp->ng_str[NG_USER])
 166                         free(ogp->ng_str[NG_USER]);
 167                 if (ogp->ng_str[NG_DOM])
 168                         free(ogp->ng_str[NG_DOM]);
 169                 free((char *)ogp);
 170         }
 171         grouphead.gr = (struct netgrp *)0;
 172 }
 173
 174 /*
 175  * Parse the netgroup file setting up the linked lists.
 176  */
 177 static int
 178 parse_netgrp(group)
 179         char *group;
 180 {
 181         register char *spos, *epos;
 182         register int len, strpos;
 183 #ifdef DEBUG
 184         register int fields;
 185 #endif
 186         char *pos, *gpos;
 187         struct netgrp *grp;
 188         struct linelist *lp = linehead;
 189
 190         /*
 191          * First, see if the line has already been read in.
 192          */
 193         while (lp) {
 194                 if (!strcmp(group, lp->l_groupname))
 195                         break;
 196                 lp = lp->l_next;
 197         }
 198         if (lp == (struct linelist *)0 &&
 199             (lp = read_for_group(group)) == (struct linelist *)0)
 200                 return (1);
 201         if (lp->l_parsed) {
 202 #ifdef DEBUG
 203                 /*
 204                  * This error message is largely superfluous since the
 205                  * code handles the error condition successfully, and
 206                  * spewing it out from inside libc can actually hose
 207                  * certain programs.
 208                  */
 209                 warnx("cycle in netgroup %s", lp->l_groupname);
 210 #endif
 211                 return (1);
 212         } else
 213                 lp->l_parsed = 1;
 214         pos = lp->l_line;
 215         /* Watch for null pointer dereferences, dammit! */
 216         while (pos != NULL && *pos != '\0') {
 217                 if (*pos == '(') {
 218                         grp = (struct netgrp *)malloc(sizeof (struct netgrp));
 219                         bzero((char *)grp, sizeof (struct netgrp));
 220                         grp->ng_next = grouphead.gr;
 221                         grouphead.gr = grp;
 222                         pos++;
 223                         gpos = strsep(&pos, ")");
 224 #ifdef DEBUG
 225                         fields = 0;
 226 #endif
 227                         for (strpos = 0; strpos < 3; strpos++) {
 228                                 if ((spos = strsep(&gpos, ","))) {
 229 #ifdef DEBUG
 230                                         fields++;
 231 #endif
 232                                         while (*spos == ' ' || *spos == '\t')
 233                                                 spos++;
 234                                         if ((epos = strpbrk(spos, " \t"))) {
 235                                                 *epos = '\0';
 236                                                 len = epos - spos;
 237                                         } else
 238                                                 len = strlen(spos);
 239                                         if (len > 0) {
 240                                                 grp->ng_str[strpos] =  (char *)
 241                                                         malloc(len + 1);
 242                                                 bcopy(spos, grp->ng_str[strpos],
 243                                                         len + 1);
 244                                         }
 245                                 } else {
 246                                         /*
 247                                          * All other systems I've tested
 248                                          * return NULL for empty netgroup
 249                                          * fields. It's up to user programs
 250                                          * to handle the NULLs appropriately.
 251                                          */
 252                                         grp->ng_str[strpos] = NULL;
 253                                 }
 254                         }
 255 #ifdef DEBUG
 256                         /*
 257                          * Note: on other platforms, malformed netgroup
 258                          * entries are not normally flagged. While we
 259                          * can catch bad entries and report them, we should
 260                          * stay silent by default for compatibility's sake.
 261                          */
 262                         if (fields < 3)
 263                                         warnx("bad entry (%s%s%s%s%s) in netgroup \"%s\"",
 264                                                 grp->ng_str[NG_HOST] == NULL ? "" : grp->ng_str[NG_HOST],
 265                                                 grp->ng_str[NG_USER] == NULL ? "" : ",",
 266                                                 grp->ng_str[NG_USER] == NULL ? "" : grp->ng_str[NG_USER],
 267                                                 grp->ng_str[NG_DOM] == NULL ? "" : ",",
 268                                                 grp->ng_str[NG_DOM] == NULL ? "" : grp->ng_str[NG_DOM],
 269                                                 lp->l_groupname);
 270 #endif
 271                 } else {
 272                         spos = strsep(&pos, ", \t");
 273                         if (parse_netgrp(spos))
 274                                 continue;
 275                 }
 276                 /* Watch for null pointer dereferences, dammit! */
 277                 if (pos != NULL)
 278                         while (*pos == ' ' || *pos == ',' || *pos == '\t')
 279                                 pos++;
 280         }
 281         return (0);
 282 }
 283
 284 /*
 285  * Read the netgroup file and save lines until the line for the netgroup
 286  * is found. Return 1 if eof is encountered.
 287  */
 288 static struct linelist *
 289 read_for_group(group)
 290         char *group;
 291 {
 292         register char *pos, *spos, *linep = NULL, *olinep = NULL;
 293         register int len, olen;
 294         int cont;
 295         struct linelist *lp;
 296         char line[LINSIZ + 1];
 297         char *data = NULL;
 298
 299         data = lookup (gtable, group);
 300         sprintf(line, "%s %s", group, data);
 301         pos = (char *)&line;
 302 #ifdef CANT_HAPPEN
 303         if (*pos == '#')
 304                 continue;
 305 #endif
 306         while (*pos == ' ' || *pos == '\t')
 307                 pos++;
 308         spos = pos;
 309         while (*pos != ' ' && *pos != '\t' && *pos != '\n' &&
 310                 *pos != '\0')
 311                 pos++;
 312         len = pos - spos;
 313         while (*pos == ' ' || *pos == '\t')
 314                 pos++;
 315         if (*pos != '\n' && *pos != '\0') {
 316                 lp = (struct linelist *)malloc(sizeof (*lp));
 317                 lp->l_parsed = 0;
 318                 lp->l_groupname = (char *)malloc(len + 1);
 319                 bcopy(spos, lp->l_groupname, len);
 320                 *(lp->l_groupname + len) = '\0';
 321                 len = strlen(pos);
 322                 olen = 0;
 323                         /*
 324                          * Loop around handling line continuations.
 325                          */
 326                         do {
 327                                 if (*(pos + len - 1) == '\n')
 328                                         len--;
 329                                 if (*(pos + len - 1) == '\\') {
 330                                         len--;
 331                                         cont = 1;
 332                                 } else
 333                                         cont = 0;
 334                                 if (len > 0) {
 335                                         linep = (char *)malloc(olen + len + 1);
 336                                         if (olen > 0) {
 337                                                 bcopy(olinep, linep, olen);
 338                                                 free(olinep);
 339                                         }
 340                                         bcopy(pos, linep + olen, len);
 341                                         olen += len;
 342                                         *(linep + olen) = '\0';
 343                                         olinep = linep;
 344                                 }
 345 #ifdef CANT_HAPPEN
 346                                 if (cont) {
 347                                         if (fgets(line, LINSIZ, netf)) {
 348                                                 pos = line;
 349                                                 len = strlen(pos);
 350                                         } else
 351                                                 cont = 0;
 352                                 }
 353 #endif
 354                         } while (cont);
 355                 lp->l_line = linep;
 356                 lp->l_next = linehead;
 357                 linehead = lp;
 358 #ifdef CANT_HAPPEN
 359                 /*
 360                  * If this is the one we wanted, we are done.
 361                  */
 362                 if (!strcmp(lp->l_groupname, group))
 363 #endif
 364                         return (lp);
 365         }
 366         return ((struct linelist *)0);
 367 }