libexec/ld.elf_so/paths.c

   1 /*      $NetBSD: paths.c,v 1.41 2013/05/06 08:02:20 skrll Exp $  */
   2
   3 /*
   4  * Copyright 1996 Matt Thomas <matt@3am-software.com>
   5  * Copyright 2002 Charles M. Hannum <root@ihack.net>
   6  * All rights reserved.
   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. The name of the author may not be used to endorse or promote products
  17  *    derived from this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #include <sys/cdefs.h>
  32 #ifndef lint
  33 __RCSID("$NetBSD: paths.c,v 1.41 2013/05/06 08:02:20 skrll Exp $");
  34 #endif /* not lint */
  35
  36 #include <err.h>
  37 #include <errno.h>
  38 #include <fcntl.h>
  39 #include <stdarg.h>
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <unistd.h>
  44 #include <sys/types.h>
  45 #include <sys/param.h>
  46 #include <sys/sysctl.h>
  47 #include <sys/mman.h>
  48 #include <sys/stat.h>
  49 #include <sys/gmon.h>
  50 #include <sys/socket.h>
  51 #include <sys/mount.h>
  52 #include <sys/mbuf.h>
  53 #include <sys/resource.h>
  54 #include <machine/cpu.h>
  55
  56 #include "debug.h"
  57 #include "rtld.h"
  58
  59 static Search_Path *_rtld_find_path(Search_Path *, const char *, size_t);
  60 static Search_Path **_rtld_append_path(Search_Path **, Search_Path **,
  61     const char *, const char *, const char *);
  62 static void _rtld_process_mapping(Library_Xform **, const char *,
  63     const char *);
  64 static char *exstrdup(const char *, const char *);
  65 static const char *getstr(const char **, const char *, const char *);
  66 static const char *getcstr(const char **, const char *, const char *);
  67 static const char *getword(const char **, const char *, const char *);
  68 static int matchstr(const char *, const char *, const char *);
  69
  70 static const char WS[] = " \t\n";
  71
  72 /*
  73  * Like xstrdup(), but takes end of string as a argument.
  74  */
  75 static char *
  76 exstrdup(const char *bp, const char *ep)
  77 {
  78         char *cp;
  79         size_t len = ep - bp;
  80
  81         cp = xmalloc(len + 1);
  82         memcpy(cp, bp, len);
  83         cp[len] = '\0';
  84         return (cp);
  85 }
  86
  87 /*
  88  * Like strsep(), but takes end of string and doesn't put any NUL.  To
  89  * detect empty string, compare `*p' and return value.
  90  */
  91 static const char *
  92 getstr(const char **p, const char *ep, const char *delim)
  93 {
  94         const char *cp = *p, *q, *r;
  95
  96         if (ep < cp)
  97                 /* End of string */
  98                 return (NULL);
  99
 100         for (q = cp; q < ep; q++)
 101                 for (r = delim; *r != 0; r++)
 102                         if (*r == *q)
 103                                 goto done;
 104
 105 done:
 106         *p = q;
 107         return (cp);
 108 }
 109
 110 /*
 111  * Like getstr() above, but delim[] is complemented.
 112  */
 113 static const char *
 114 getcstr(const char **p, const char *ep, const char *delim)
 115 {
 116         const char *cp = *p, *q, *r;
 117
 118         if (ep < cp)
 119                 /* End of string */
 120                 return (NULL);
 121
 122         for (q = cp; q < ep; q++)
 123                 for (r = delim; *r != *q; r++)
 124                         if (*r == 0)
 125                                 goto done;
 126
 127 done:
 128         *p = q;
 129         return (cp);
 130 }
 131
 132 static const char *
 133 getword(const char **p, const char *ep, const char *delim)
 134 {
 135
 136         (void)getcstr(p, ep, delim);
 137
 138         /*
 139          * Now, we're looking non-delim, or end of string.
 140          */
 141
 142         return (getstr(p, ep, delim));
 143 }
 144
 145 /*
 146  * Match `bp' against NUL terminated string pointed by `p'.
 147  */
 148 static int
 149 matchstr(const char *p, const char *bp, const char *ep)
 150 {
 151         int c;
 152
 153         while (bp < ep)
 154                 if ((c = *p++) == 0 || c != *bp++)
 155                         return (0);
 156
 157         return (*p == 0);
 158 }
 159
 160 static Search_Path *
 161 _rtld_find_path(Search_Path *path, const char *pathstr, size_t pathlen)
 162 {
 163
 164         for (; path != NULL; path = path->sp_next) {
 165                 if (pathlen == path->sp_pathlen &&
 166                     memcmp(path->sp_path, pathstr, pathlen) == 0)
 167                         return path;
 168         }
 169         return NULL;
 170 }
 171
 172 static Search_Path **
 173 _rtld_append_path(Search_Path **head_p, Search_Path **path_p,
 174     const char *execname, const char *bp, const char *ep)
 175 {
 176         Search_Path *path;
 177         char epath[MAXPATHLEN];
 178         size_t len;
 179
 180         len = _rtld_expand_path(epath, sizeof(epath), execname, bp, ep);
 181         if (len == 0)
 182                 return path_p;
 183
 184         if (_rtld_find_path(*head_p, bp, ep - bp) != NULL)
 185                 return path_p;
 186
 187         path = NEW(Search_Path);
 188         path->sp_pathlen = len;
 189         path->sp_path = exstrdup(epath, epath + len);
 190         path->sp_next = (*path_p);
 191         (*path_p) = path;
 192         path_p = &path->sp_next;
 193
 194         dbg((" added path \"%s\"", path->sp_path));
 195         return path_p;
 196 }
 197
 198 void
 199 _rtld_add_paths(const char *execname, Search_Path **path_p, const char *pathstr)
 200 {
 201         Search_Path **head_p = path_p;
 202
 203         if (pathstr == NULL)
 204                 return;
 205
 206         if (pathstr[0] == ':') {
 207                 /*
 208                  * Leading colon means append to current path
 209                  */
 210                 while ((*path_p) != NULL)
 211                         path_p = &(*path_p)->sp_next;
 212                 pathstr++;
 213         }
 214
 215         for (;;) {
 216                 const char *bp = pathstr;
 217                 const char *ep = strchr(bp, ':');
 218                 if (ep == NULL)
 219                         ep = &pathstr[strlen(pathstr)];
 220
 221                 path_p = _rtld_append_path(head_p, path_p, execname, bp, ep);
 222
 223                 if (ep[0] == '\0')
 224                         break;
 225                 pathstr = ep + 1;
 226         }
 227 }
 228
 229 /*
 230  * Process library mappings of the form:
 231  *      <library_name>  <machdep_variable> <value,...:library_name,...> ...
 232  */
 233 static void
 234 _rtld_process_mapping(Library_Xform **lib_p, const char *bp, const char *ep)
 235 {
 236         Library_Xform *hwptr = NULL;
 237         const char *ptr, *key, *ekey, *lib, *elib, *l;
 238         int i, j;
 239
 240         dbg((" processing mapping \"%.*s\"", (int)(ep - bp), bp));
 241
 242         if ((ptr = getword(&bp, ep, WS)) == NULL || ptr == bp)
 243                 return;
 244
 245         dbg((" library \"%.*s\"", (int)(bp - ptr), ptr));
 246
 247         hwptr = xmalloc(sizeof(*hwptr));
 248         memset(hwptr, 0, sizeof(*hwptr));
 249         hwptr->name = exstrdup(ptr, bp);
 250
 251         bp++;
 252
 253         if ((ptr = getword(&bp, ep, WS)) == NULL || ptr == bp) {
 254                 xwarnx("missing sysctl variable name");
 255                 goto cleanup;
 256         }
 257
 258         dbg((" sysctl \"%.*s\"", (int)(bp - ptr), ptr));
 259
 260         hwptr->ctlname = exstrdup(ptr, bp);
 261
 262         for (i = 0; bp++, (ptr = getword(&bp, ep, WS)) != NULL;) {
 263                 dbg((" ptr = %.*s", (int)(bp - ptr), ptr));
 264                 if (ptr == bp)
 265                         continue;
 266
 267                 if (i == RTLD_MAX_ENTRY) {
 268 no_more:
 269                         xwarnx("maximum library entries exceeded `%s'",
 270                             hwptr->name);
 271                         goto cleanup;
 272                 }
 273                 if ((key = getstr(&ptr, bp, ":")) == NULL) {
 274                         xwarnx("missing sysctl variable value for `%s'",
 275                             hwptr->name);
 276                         goto cleanup;
 277                 }
 278                 ekey = ptr++;
 279                 if ((lib = getstr(&ptr, bp, ":")) == NULL) {
 280                         xwarnx("missing sysctl library list for `%s'",
 281                             hwptr->name);
 282                         goto cleanup;
 283                 }
 284                 elib = ptr;             /* No need to advance */
 285                 for (j = 0; (l = getstr(&lib, elib, ",")) != NULL;
 286                     j++, lib++) {
 287                         if (j == RTLD_MAX_LIBRARY) {
 288                                 xwarnx("maximum library entries exceeded `%s'",
 289                                     hwptr->name);
 290                                 goto cleanup;
 291                         }
 292                         dbg((" library \"%.*s\"", (int)(lib - l), l));
 293                         hwptr->entry[i].library[j] = exstrdup(l, lib);
 294                 }
 295                 if (j == 0) {
 296                         xwarnx("No library map entries for `%s/%.*s'",
 297                             hwptr->name, (int)(bp - ptr), ptr);
 298                         goto cleanup;
 299                 }
 300                 j = i;
 301                 for (; (l = getstr(&key, ekey, ",")) != NULL; i++, key++) {
 302                         /*
 303                          * Allow empty key (it is valid as string
 304                          * value).  Thus, we loop at least once and
 305                          * `i' is incremented.
 306                          */
 307
 308                         dbg((" key \"%.*s\"", (int)(key - l), l));
 309                         if (i == RTLD_MAX_ENTRY)
 310                                 goto no_more;
 311                         if (i != j)
 312                                 (void)memcpy(hwptr->entry[i].library,
 313                                     hwptr->entry[j].library,
 314                                     sizeof(hwptr->entry[j].library));
 315                         hwptr->entry[i].value = exstrdup(l, key);
 316                 }
 317         }
 318
 319         if (i == 0) {
 320                 xwarnx("No library entries for `%s'", hwptr->name);
 321                 goto cleanup;
 322         }
 323
 324         hwptr->next = *lib_p;
 325         *lib_p = hwptr;
 326
 327         return;
 328
 329 cleanup:
 330         if (hwptr->name)
 331                 xfree(hwptr->name);
 332         xfree(hwptr);
 333 }
 334
 335 void
 336 _rtld_process_hints(const char *execname, Search_Path **path_p,
 337     Library_Xform **lib_p, const char *fname)
 338 {
 339         int fd;
 340         char *buf, small[128];
 341         const char *b, *ep, *ptr;
 342         struct stat st;
 343         ssize_t sz;
 344         Search_Path **head_p = path_p;
 345
 346         if ((fd = open(fname, O_RDONLY)) == -1) {
 347                 /* Don't complain */
 348                 return;
 349         }
 350
 351         /* Try to avoid mmap/stat on the file. */
 352         buf = small;
 353         buf[0] = '\0';
 354         sz = read(fd, buf, sizeof(small));
 355         if (sz == -1) {
 356                 xwarn("read: %s", fname);
 357                 (void)close(fd);
 358                 return;
 359         }
 360         if (sz >= (ssize_t)sizeof(small)) {
 361                 if (fstat(fd, &st) == -1) {
 362                         /* Complain */
 363                         xwarn("fstat: %s", fname);
 364                         (void)close(fd);
 365                         return;
 366                 }
 367
 368                 sz = (ssize_t) st.st_size;
 369
 370                 buf = mmap(0, sz, PROT_READ, MAP_SHARED|MAP_FILE, fd, 0);
 371                 if (buf == MAP_FAILED) {
 372                         xwarn("mmap: %s", fname);
 373                         (void)close(fd);
 374                         return;
 375                 }
 376         }
 377         (void)close(fd);
 378
 379         while ((*path_p) != NULL)
 380                 path_p = &(*path_p)->sp_next;
 381
 382         for (b = buf, ep = buf + sz; b < ep; b++) {
 383                 (void)getcstr(&b, ep, WS);
 384                 if (b == ep)
 385                         break;
 386
 387                 ptr = getstr(&b, ep, "\n#");
 388                 if (*ptr == '/') {
 389                         /*
 390                          * Since '/' != '\n' and != '#', we know ptr <
 391                          * b.  And we will stop when b[-1] == '/'.
 392                          */
 393                         while (b[-1] == ' ' || b[-1] == '\t')
 394                                 b--;
 395                         path_p = _rtld_append_path(head_p, path_p, execname,
 396                             ptr, b);
 397                 } else
 398                         _rtld_process_mapping(lib_p, ptr, b);
 399
 400                 /*
 401                  * b points one of ' ', \t, \n, # or equal to ep.  So,
 402                  * make sure we are at newline or end of string.
 403                  */
 404                 (void)getstr(&b, ep, "\n");
 405         }
 406
 407         if (buf != small)
 408                 (void)munmap(buf, sz);
 409 }
 410
 411 /* Basic name -> sysctl MIB translation */
 412 int
 413 _rtld_sysctl(const char *name, void *oldp, size_t *oldlen)
 414 {
 415         const char *node, *ep;
 416         struct sysctlnode query, *result, *newresult;
 417         int mib[CTL_MAXNAME], r;
 418         size_t res_size, n, i;
 419         u_int miblen = 0;
 420
 421         /* Start with 16 entries, will grow it up as needed. */
 422         res_size = 16 * sizeof(struct sysctlnode);
 423         result = xmalloc(res_size);
 424         if (result == NULL)
 425                 return (-1);
 426
 427         ep = name + strlen(name);
 428         do {
 429                 i = ~0ul;
 430                 while (*name == '/' || *name == '.')
 431                         name++;
 432                 if (name >= ep)
 433                         break;
 434
 435                 mib[miblen] = CTL_QUERY;
 436                 memset(&query, 0, sizeof(query));
 437                 query.sysctl_flags = SYSCTL_VERSION;
 438
 439                 n = res_size;
 440                 if (sysctl(mib, miblen + 1, result, &n, &query,
 441                     sizeof(query)) == -1) {
 442                         if (errno != ENOMEM)
 443                                 goto bad;
 444                         /* Grow up result */
 445                         res_size = n;
 446                         newresult = xrealloc(result, res_size);
 447                         if (newresult == NULL)
 448                                 goto bad;
 449                         result = newresult;
 450                         if (sysctl(mib, miblen + 1, result, &n, &query,
 451                             sizeof(query)) == -1)
 452                                 goto bad;
 453                 }
 454                 n /= sizeof(struct sysctlnode);
 455
 456                 node = getstr(&name, ep, "./");
 457
 458                 for (i = 0; i < n; i++)
 459                         if (matchstr(result[i].sysctl_name, node, name)) {
 460                                 mib[miblen] = result[i].sysctl_num;
 461                                 miblen++;
 462                                 break;
 463                         }
 464         } while (name < ep && miblen <= CTL_MAXNAME);
 465
 466         if (name < ep || i == ~0ul)
 467                 goto bad;
 468         r = SYSCTL_TYPE(result[i].sysctl_flags);
 469
 470         xfree(result);
 471         if (sysctl(mib, miblen, oldp, oldlen, NULL, 0) == -1)
 472                 return (-1);
 473         return r;
 474
 475 bad:
 476         xfree(result);
 477         return (-1);
 478 }