getgrent.c revision 1.9
1/* $NetBSD: getgrent.c,v 1.9 2005/01/06 15:10:45 lukem Exp $ */ 2 3/* 4 * Copyright (c) 1989, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32/* 33 * Portions Copyright (c) 1994, Jason Downs. All Rights Reserved. 34 * 35 * Redistribution and use in source and binary forms, with or without 36 * modification, are permitted provided that the following conditions 37 * are met: 38 * 1. Redistributions of source code must retain the above copyright 39 * notice, this list of conditions and the following disclaimer. 40 * 2. Redistributions in binary form must reproduce the above copyright 41 * notice, this list of conditions and the following disclaimer in the 42 * documentation and/or other materials provided with the distribution. 43 * 44 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS 45 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 46 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 47 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, 48 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 49 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 50 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 51 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 52 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 53 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 54 * SUCH DAMAGE. 55 */ 56 57/* 58 * Copied from: lib/libc/gen/getgrent.c 59 * NetBSD: getgrent.c,v 1.46 2003/02/17 00:11:54 simonb Exp 60 * and then gutted, leaving only /etc/group support. 61 */ 62 63#include <sys/cdefs.h> 64 65#ifdef __weak_alias 66#define endgrent _endgrent 67#define getgrent _getgrent 68#define getgrgid _getgrgid 69#define getgrnam _getgrnam 70#define setgrent _setgrent 71#define setgroupent _setgroupent 72#define getgroupmembership _getgroupmembership 73 74__weak_alias(endgrent,_endgrent) 75__weak_alias(getgrent,_getgrent) 76__weak_alias(getgrgid,_getgrgid) 77__weak_alias(getgrnam,_getgrnam) 78__weak_alias(setgrent,_setgrent) 79__weak_alias(setgroupent,_setgroupent) 80__weak_alias(getgroupmembership,_getgroupmembership) 81#endif 82 83#include <sys/param.h> 84 85#include <grp.h> 86#include <limits.h> 87#include <stdio.h> 88#include <stdlib.h> 89#include <string.h> 90 91static FILE *_gr_fp; 92static struct group _gr_group; 93static int _gr_stayopen; 94static int _gr_filesdone; 95 96static int grscan(int, gid_t, const char *, const char *); 97static int grstart(void); 98static int grmatchline(int, gid_t, const char *, const char *); 99 100#define MAXGRP 200 101#define MAXLINELENGTH 1024 102 103static __aconst char *members[MAXGRP]; 104static char grline[MAXLINELENGTH]; 105 106struct group * 107getgrent(void) 108{ 109 110 if ((!_gr_fp && !grstart()) || !grscan(0, 0, NULL, NULL)) 111 return (NULL); 112 return &_gr_group; 113} 114 115struct group * 116getgrnam(const char *name) 117{ 118 int rval; 119 120 if (!grstart()) 121 return NULL; 122 rval = grscan(1, 0, name, NULL); 123 if (!_gr_stayopen) 124 endgrent(); 125 return (rval) ? &_gr_group : NULL; 126} 127 128struct group * 129getgrgid(gid_t gid) 130{ 131 int rval; 132 133 if (!grstart()) 134 return NULL; 135 rval = grscan(1, gid, NULL, NULL); 136 if (!_gr_stayopen) 137 endgrent(); 138 return (rval) ? &_gr_group : NULL; 139} 140 141static int 142grstart(void) 143{ 144 145 _gr_filesdone = 0; 146 if (_gr_fp) { 147 rewind(_gr_fp); 148 return 1; 149 } 150 return (_gr_fp = fopen(_PATH_GROUP, "r")) ? 1 : 0; 151} 152 153void 154setgrent(void) 155{ 156 157 (void) setgroupent(0); 158} 159 160int 161setgroupent(int stayopen) 162{ 163 164 if (!grstart()) 165 return 0; 166 _gr_stayopen = stayopen; 167 return 1; 168} 169 170void 171endgrent(void) 172{ 173 174 _gr_filesdone = 0; 175 if (_gr_fp) { 176 (void)fclose(_gr_fp); 177 _gr_fp = NULL; 178 } 179} 180 181int 182getgroupmembership(const char *uname, gid_t agroup, 183 gid_t *groups, int maxgroups, int *grpcnt) 184{ 185 struct group *grp; 186 int i, ngroups, ret; 187 188 ret = 0; 189 ngroups = 0; 190 191 /* 192 * install primary group 193 */ 194 if (ngroups < maxgroups) 195 groups[ngroups] = agroup; 196 else 197 ret = -1; 198 ngroups++; 199 200 /* 201 * Scan the group file to find additional groups. 202 */ 203 setgrent(); 204 nextgroup: 205 while ((grp = getgrent()) != NULL) { 206 if (grp->gr_gid == agroup) 207 continue; 208 for (i = 0; grp->gr_mem[i]; i++) { 209 if (strcmp(grp->gr_mem[i], uname) != 0) 210 continue; 211 for (i = 0; i < MIN(ngroups, maxgroups); i++) { 212 if (grp->gr_gid == groups[i]) 213 goto nextgroup; 214 } 215 if (ngroups < maxgroups) 216 groups[ngroups] = grp->gr_gid; 217 else 218 ret = -1; 219 ngroups++; 220 break; 221 } 222 } 223 endgrent(); 224 *grpcnt = ngroups; 225 return ret; 226} 227 228static int 229grscan(int search, gid_t gid, const char *name, const char *user) 230{ 231 232 if (_gr_filesdone) 233 return 0; 234 for (;;) { 235 if (!fgets(grline, sizeof(grline), _gr_fp)) { 236 if (!search) 237 _gr_filesdone = 1; 238 return 0; 239 } 240 /* skip lines that are too big */ 241 if (!strchr(grline, '\n')) { 242 int ch; 243 244 while ((ch = getc(_gr_fp)) != '\n' && ch != EOF) 245 ; 246 continue; 247 } 248 if (grmatchline(search, gid, name, user)) 249 return 1; 250 } 251 /* NOTREACHED */ 252} 253 254static int 255grmatchline(int search, gid_t gid, const char *name, const char *user) 256{ 257 unsigned long id; 258 __aconst char **m; 259 char *cp, *bp, *ep; 260 261 /* name may be NULL if search is nonzero */ 262 263 bp = grline; 264 _gr_group.gr_name = strsep(&bp, ":\n"); 265 if (search && name && strcmp(_gr_group.gr_name, name)) 266 return 0; 267 _gr_group.gr_passwd = strsep(&bp, ":\n"); 268 if (!(cp = strsep(&bp, ":\n"))) 269 return 0; 270 id = strtoul(cp, &ep, 10); 271 if (id > GID_MAX || *ep != '\0') 272 return 0; 273 _gr_group.gr_gid = (gid_t)id; 274 if (search && name == NULL && _gr_group.gr_gid != gid) 275 return 0; 276 cp = NULL; 277 if (bp == NULL) 278 return 0; 279 for (_gr_group.gr_mem = m = members;; bp++) { 280 if (m == &members[MAXGRP - 1]) 281 break; 282 if (*bp == ',') { 283 if (cp) { 284 *bp = '\0'; 285 *m++ = cp; 286 cp = NULL; 287 } 288 } else if (*bp == '\0' || *bp == '\n' || *bp == ' ') { 289 if (cp) { 290 *bp = '\0'; 291 *m++ = cp; 292 } 293 break; 294 } else if (cp == NULL) 295 cp = bp; 296 } 297 *m = NULL; 298 if (user) { 299 for (m = members; *m; m++) 300 if (!strcmp(user, *m)) 301 return 1; 302 return 0; 303 } 304 return 1; 305} 306