sbin/mount_portal/conf.c

   1 /*
   2  * Copyright (c) 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  * All rights reserved.
   5  *
   6  * This code is derived from software donated to Berkeley by
   7  * Jan-Simon Pendry.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed by the University of
  20  *      California, Berkeley and its contributors.
  21  * 4. Neither the name of the University nor the names of its contributors
  22  *    may be used to endorse or promote products derived from this software
  23  *    without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  35  * SUCH DAMAGE.
  36  *
  37  *      @(#)conf.c      8.2 (Berkeley) 3/27/94
  38  *
  39  * $FreeBSD: src/sbin/mount_portal/conf.c,v 1.8 1999/08/28 00:13:35 peter Exp $
  40  * $DragonFly: src/sbin/mount_portal/conf.c,v 1.4 2004/12/18 21:43:39 swildner Exp $
  41  */
  42
  43 #include <errno.h>
  44 #include <limits.h>
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <string.h>
  48 #include <unistd.h>
  49 #include <regex.h>
  50 #include <sys/types.h>
  51 #include <sys/param.h>
  52 #include <sys/syslog.h>
  53
  54 #include "portald.h"
  55
  56 #define ALLOC(ty)       (xmalloc(sizeof(ty)))
  57
  58 typedef struct path path;
  59 struct path {
  60         qelem p_q;              /* 2-way linked list */
  61         int p_lno;              /* Line number of this record */
  62         char *p_args;           /* copy of arg string (malloc) */
  63         char *p_key;            /* Pathname to match (also p_argv[0]) */
  64         regex_t p_rx;           /* RE to match against pathname () */
  65         int p_rxvalid;          /* non-zero if valid regular expression */
  66         int p_argc;             /* number of elements in arg string */
  67         char **p_argv;          /* argv[] pointers into arg string (malloc) */
  68 };
  69
  70 static char *conf_file;         /* XXX for regerror */
  71 static path *curp;              /* XXX for regerror */
  72
  73 /*
  74  * Add an element to a 2-way list,
  75  * just after (pred)
  76  */
  77 static void ins_que(qelem *elem, qelem *pred)
  78 {
  79         qelem *p = pred->q_forw;
  80         elem->q_back = pred;
  81         elem->q_forw = p;
  82         pred->q_forw = elem;
  83         p->q_back = elem;
  84 }
  85
  86 /*
  87  * Remove an element from a 2-way list
  88  */
  89 static void rem_que(qelem *elem)
  90 {
  91         qelem *p = elem->q_forw;
  92         qelem *p2 = elem->q_back;
  93         p2->q_forw = p;
  94         p->q_back = p2;
  95 }
  96
  97 /*
  98  * Error checking malloc
  99  */
 100 static void *xmalloc(unsigned siz)
 101 {
 102         void *p = malloc(siz);
 103         if (p)
 104                 return (p);
 105         syslog(LOG_ALERT, "malloc: failed to get %d bytes", siz);
 106         exit(1);
 107 }
 108
 109 /*
 110  * Insert the path in the list.
 111  * If there is already an element with the same key then
 112  * the *second* one is ignored (return 0).  If the key is
 113  * not found then the path is added to the end of the list
 114  * and 1 is returned.
 115  */
 116 static int pinsert(path *p0, qelem *q0)
 117 {
 118         qelem *q;
 119
 120         if (p0->p_argc == 0)
 121                 return (0);
 122
 123         for (q = q0->q_forw; q != q0; q = q->q_forw) {
 124                 path *p = (path *) q;
 125                 if (strcmp(p->p_key, p0->p_key) == 0)
 126                         return (0);
 127         }
 128         ins_que(&p0->p_q, q0->q_back);
 129         return (1);
 130
 131 }
 132
 133 static path *palloc(char *cline, int lno)
 134 {
 135         int c;
 136         char *s;
 137         char *key;
 138         path *p;
 139         char **ap;
 140
 141         /*
 142          * Implement comment chars
 143          */
 144         s = strchr(cline, '#');
 145         if (s)
 146                 *s = 0;
 147
 148         /*
 149          * Do a pass through the string to count the number
 150          * of arguments
 151          */
 152         c = 0;
 153         key = strdup(cline);
 154         for (s = key; s != NULL; ) {
 155                 char *val;
 156                 while ((val = strsep(&s, " \t\n")) != NULL && *val == '\0')
 157                         ;
 158                 if (val)
 159                         c++;
 160         }
 161         c++;
 162         free(key);
 163
 164         if (c <= 1)
 165                 return (0);
 166
 167         /*
 168          * Now do another pass and generate a new path structure
 169          */
 170         p = ALLOC(path);
 171         p->p_argc = 0;
 172         p->p_argv = xmalloc(c * sizeof(char *));
 173         p->p_args = strdup(cline);
 174         ap = p->p_argv;
 175         for (s = p->p_args; s != NULL; ) {
 176                 char *val;
 177                 while ((val = strsep(&s, " \t\n")) != NULL && *val == '\0')
 178                         ;
 179                 if (val) {
 180                         *ap++ = val;
 181                         p->p_argc++;
 182                 }
 183         }
 184         *ap = 0;
 185
 186 #ifdef DEBUG
 187         for (c = 0; c < p->p_argc; c++)
 188                 printf("%sv[%d] = %s\n", c?"\t":"", c, p->p_argv[c]);
 189 #endif
 190
 191         p->p_key = p->p_argv[0];
 192         if (strpbrk(p->p_key, RE_CHARS)) {
 193                 int val;
 194
 195                 curp = p;                       /* XXX */
 196                 val = regcomp(&p->p_rx, p->p_key, REG_EXTENDED | REG_NOSUB);
 197                 if (val) {
 198                         char errbuf[_POSIX2_LINE_MAX];
 199                         regerror(val, &p->p_rx, errbuf, sizeof errbuf);
 200                         syslog(LOG_ERR, "%s:%d: regcomp %s: %s",
 201                                conf_file, curp->p_lno, curp->p_key, errbuf);
 202                         regfree(&p->p_rx);
 203                         p->p_rxvalid = 0;
 204                 } else {
 205                         p->p_rxvalid = 1;
 206                 }
 207                 curp = 0;                       /* XXX */
 208         } else {
 209                 p->p_rxvalid = 0;
 210         }
 211         p->p_lno = lno;
 212
 213         return (p);
 214 }
 215
 216 /*
 217  * Free a path structure
 218  */
 219 static void pfree(path *p)
 220 {
 221         free(p->p_args);
 222         if (p->p_rxvalid) {
 223                 regfree(&p->p_rx);
 224         }
 225         free((char *) p->p_argv);
 226         free((char *) p);
 227 }
 228
 229 /*
 230  * Discard all currently held path structures on q0.
 231  * and add all the ones on xq.
 232  */
 233 static void preplace(qelem *q0, qelem *xq)
 234 {
 235         /*
 236          * While the list is not empty,
 237          * take the first element off the list
 238          * and free it.
 239          */
 240         while (q0->q_forw != q0) {
 241                 qelem *q = q0->q_forw;
 242                 rem_que(q);
 243                 pfree((path *) q);
 244         }
 245         while (xq->q_forw != xq) {
 246                 qelem *q = xq->q_forw;
 247                 rem_que(q);
 248                 ins_que(q, q0);
 249         }
 250 }
 251
 252 /*
 253  * Read the lines from the configuration file and
 254  * add them to the list of paths.
 255  */
 256 static void readfp(qelem *q0, FILE *fp)
 257 {
 258         char cline[LINE_MAX];
 259         int nread = 0;
 260         qelem q;
 261
 262         /*
 263          * Make a new empty list.
 264          */
 265         q.q_forw = q.q_back = &q;
 266
 267         /*
 268          * Read the lines from the configuration file.
 269          */
 270         while (fgets(cline, sizeof(cline), fp)) {
 271                 path *p = palloc(cline, nread+1);
 272                 if (p && !pinsert(p, &q))
 273                         pfree(p);
 274                 nread++;
 275         }
 276
 277         /*
 278          * If some records were read, then throw
 279          * away the old list and replace with the
 280          * new one.
 281          */
 282         if (nread)
 283                 preplace(q0, &q);
 284 }
 285
 286 /*
 287  * Read the configuration file (conf) and replace
 288  * the existing path list with the new version.
 289  * If the file is not readable, then no changes take place
 290  */
 291 void conf_read(qelem *q, char *conf)
 292 {
 293         FILE *fp = fopen(conf, "r");
 294         if (fp) {
 295                 conf_file = conf;               /* XXX */
 296                 readfp(q, fp);
 297                 conf_file = 0;          /* XXX */
 298                 fclose(fp);
 299         } else {
 300                 syslog(LOG_ERR, "open config file \"%s\": %s", conf, strerror(errno));
 301         }
 302 }
 303
 304
 305 char **conf_match(qelem *q0, char *key)
 306 {
 307         qelem *q;
 308
 309         for (q = q0->q_forw; q != q0; q = q->q_forw) {
 310                 path *p = (path *) q;
 311                 if (p->p_rxvalid) {
 312                         if (!regexec(&p->p_rx, key, 0, 0, 0)) {
 313                                 return p->p_argv + 1;
 314                         }
 315                 } else {
 316                         if (strncmp(p->p_key, key, strlen(p->p_key)) == 0)
 317                                 return (p->p_argv+1);
 318                 }
 319         }
 320
 321         return (0);
 322 }