libexec/rtld-elf/libmap.c

   1 /*
   2  * $FreeBSD$
   3  */
   4
   5 #include <sys/types.h>
   6 #include <sys/param.h>
   7 #include <sys/fcntl.h>
   8 #include <sys/mman.h>
   9 #include <sys/queue.h>
  10 #include <sys/stat.h>
  11 #include <dirent.h>
  12 #include <errno.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15
  16 #include "debug.h"
  17 #include "rtld.h"
  18 #include "libmap.h"
  19
  20 #ifndef _PATH_LIBMAP_CONF
  21 #define _PATH_LIBMAP_CONF       "/etc/libmap.conf"
  22 #endif
  23
  24 TAILQ_HEAD(lm_list, lm);
  25 struct lm {
  26         char *f;
  27         char *t;
  28         TAILQ_ENTRY(lm) lm_link;
  29 };
  30
  31 TAILQ_HEAD(lmp_list, lmp) lmp_head = TAILQ_HEAD_INITIALIZER(lmp_head);
  32 struct lmp {
  33         char *p;
  34         enum { T_EXACT=0, T_BASENAME, T_DIRECTORY } type;
  35         struct lm_list lml;
  36         TAILQ_ENTRY(lmp) lmp_link;
  37 };
  38
  39 static TAILQ_HEAD(lmc_list, lmc) lmc_head = TAILQ_HEAD_INITIALIZER(lmc_head);
  40 struct lmc {
  41         char *path;
  42         TAILQ_ENTRY(lmc) next;
  43 };
  44
  45 static int lm_count;
  46
  47 static void lmc_parse(char *, size_t);
  48 static void lmc_parse_file(char *);
  49 static void lmc_parse_dir(char *);
  50 static void lm_add(const char *, const char *, const char *);
  51 static void lm_free(struct lm_list *);
  52 static char *lml_find(struct lm_list *, const char *);
  53 static struct lm_list *lmp_find(const char *);
  54 static struct lm_list *lmp_init(char *);
  55 static const char *quickbasename(const char *);
  56
  57 #define iseol(c)        (((c) == '#') || ((c) == '\0') || \
  58                          ((c) == '\n') || ((c) == '\r'))
  59
  60 /*
  61  * Do not use ctype.h macros, which rely on working TLS.  It is
  62  * too early to have thread-local variables functional.
  63  */
  64 #define rtld_isspace(c) ((c) == ' ' || (c) == '\t')
  65
  66 int
  67 lm_init(char *libmap_override)
  68 {
  69         char *p;
  70
  71         dbg("lm_init(\"%s\")", libmap_override);
  72         TAILQ_INIT(&lmp_head);
  73
  74         lmc_parse_file(_PATH_LIBMAP_CONF);
  75
  76         if (libmap_override) {
  77                 /*
  78                  * Do some character replacement to make $LDLIBMAP look
  79                  * like a text file, then parse it.
  80                  */
  81                 libmap_override = xstrdup(libmap_override);
  82                 for (p = libmap_override; *p; p++) {
  83                         switch (*p) {
  84                         case '=':
  85                                 *p = ' ';
  86                                 break;
  87                         case ',':
  88                                 *p = '\n';
  89                                 break;
  90                         }
  91                 }
  92                 lmc_parse(libmap_override, p - libmap_override);
  93                 free(libmap_override);
  94         }
  95
  96         return (lm_count == 0);
  97 }
  98
  99 static void
 100 lmc_parse_file(char *path)
 101 {
 102         struct lmc *p;
 103         struct stat st;
 104         int fd;
 105         char *rpath;
 106         char *lm_map;
 107
 108         rpath = realpath(path, NULL);
 109         if (rpath == NULL)
 110                 return;
 111
 112         TAILQ_FOREACH(p, &lmc_head, next) {
 113                 if (strcmp(p->path, rpath) == 0) {
 114                         free(rpath);
 115                         return;
 116                 }
 117         }
 118
 119         fd = open(rpath, O_RDONLY | O_CLOEXEC);
 120         if (fd == -1) {
 121                 dbg("lm_parse_file: open(\"%s\") failed, %s", rpath,
 122                     rtld_strerror(errno));
 123                 free(rpath);
 124                 return;
 125         }
 126         if (fstat(fd, &st) == -1) {
 127                 close(fd);
 128                 dbg("lm_parse_file: fstat(\"%s\") failed, %s", rpath,
 129                     rtld_strerror(errno));
 130                 free(rpath);
 131                 return;
 132         }
 133         lm_map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 134         if (lm_map == (const char *)MAP_FAILED) {
 135                 close(fd);
 136                 dbg("lm_parse_file: mmap(\"%s\") failed, %s", rpath,
 137                     rtld_strerror(errno));
 138                 free(rpath);
 139                 return;
 140         }
 141         close(fd);
 142         p = xmalloc(sizeof(struct lmc));
 143         p->path = rpath;
 144         TAILQ_INSERT_HEAD(&lmc_head, p, next);
 145         lmc_parse(lm_map, st.st_size);
 146         munmap(lm_map, st.st_size);
 147 }
 148
 149 static void
 150 lmc_parse_dir(char *idir)
 151 {
 152         DIR *d;
 153         struct dirent *dp;
 154         struct lmc *p;
 155         char conffile[MAXPATHLEN];
 156         char *ext;
 157         char *rpath;
 158
 159         rpath = realpath(idir, NULL);
 160         if (rpath == NULL)
 161                 return;
 162
 163         TAILQ_FOREACH(p, &lmc_head, next) {
 164                 if (strcmp(p->path, rpath) == 0) {
 165                         free(rpath);
 166                         return;
 167                 }
 168         }
 169         d = opendir(idir);
 170         if (d == NULL) {
 171                 free(rpath);
 172                 return;
 173         }
 174
 175         p = xmalloc(sizeof(struct lmc));
 176         p->path = rpath;
 177         TAILQ_INSERT_HEAD(&lmc_head, p, next);
 178
 179         while ((dp = readdir(d)) != NULL) {
 180                 if (dp->d_ino == 0)
 181                         continue;
 182                 if (dp->d_type != DT_REG)
 183                         continue;
 184                 ext = strrchr(dp->d_name, '.');
 185                 if (ext == NULL)
 186                         continue;
 187                 if (strcmp(ext, ".conf") != 0)
 188                         continue;
 189                 if (strlcpy(conffile, idir, MAXPATHLEN) >= MAXPATHLEN)
 190                         continue; /* too long */
 191                 if (strlcat(conffile, "/", MAXPATHLEN) >= MAXPATHLEN)
 192                         continue; /* too long */
 193                 if (strlcat(conffile, dp->d_name, MAXPATHLEN) >= MAXPATHLEN)
 194                         continue; /* too long */
 195                 lmc_parse_file(conffile);
 196         }
 197         closedir(d);
 198 }
 199
 200 static void
 201 lmc_parse(char *lm_p, size_t lm_len)
 202 {
 203         char *cp, *f, *t, *c, *p;
 204         char prog[MAXPATHLEN];
 205         /* allow includedir + full length path */
 206         char line[MAXPATHLEN + 13];
 207         size_t cnt;
 208         int i;
 209
 210         cnt = 0;
 211         p = NULL;
 212         while (cnt < lm_len) {
 213                 i = 0;
 214                 while (cnt < lm_len && lm_p[cnt] != '\n' &&
 215                     i < sizeof(line) - 1) {
 216                         line[i] = lm_p[cnt];
 217                         cnt++;
 218                         i++;
 219                 }
 220                 line[i] = '\0';
 221                 while (cnt < lm_len && lm_p[cnt] != '\n')
 222                         cnt++;
 223                 /* skip over nl */
 224                 cnt++;
 225
 226                 cp = &line[0];
 227                 t = f = c = NULL;
 228
 229                 /* Skip over leading space */
 230                 while (rtld_isspace(*cp)) cp++;
 231
 232                 /* Found a comment or EOL */
 233                 if (iseol(*cp)) continue;
 234
 235                 /* Found a constraint selector */
 236                 if (*cp == '[') {
 237                         cp++;
 238
 239                         /* Skip leading space */
 240                         while (rtld_isspace(*cp)) cp++;
 241
 242                         /* Found comment, EOL or end of selector */
 243                         if  (iseol(*cp) || *cp == ']')
 244                                 continue;
 245
 246                         c = cp++;
 247                         /* Skip to end of word */
 248                         while (!rtld_isspace(*cp) && !iseol(*cp) && *cp != ']')
 249                                 cp++;
 250
 251                         /* Skip and zero out trailing space */
 252                         while (rtld_isspace(*cp)) *cp++ = '\0';
 253
 254                         /* Check if there is a closing brace */
 255                         if (*cp != ']') continue;
 256
 257                         /* Terminate string if there was no trailing space */
 258                         *cp++ = '\0';
 259
 260                         /*
 261                          * There should be nothing except whitespace or comment
 262                           from this point to the end of the line.
 263                          */
 264                         while(rtld_isspace(*cp)) cp++;
 265                         if (!iseol(*cp)) continue;
 266
 267                         if (strlcpy(prog, c, sizeof prog) >= sizeof prog)
 268                                 continue;
 269                         p = prog;
 270                         continue;
 271                 }
 272
 273                 /* Parse the 'from' candidate. */
 274                 f = cp++;
 275                 while (!rtld_isspace(*cp) && !iseol(*cp)) cp++;
 276
 277                 /* Skip and zero out the trailing whitespace */
 278                 while (rtld_isspace(*cp)) *cp++ = '\0';
 279
 280                 /* Found a comment or EOL */
 281                 if (iseol(*cp)) continue;
 282
 283                 /* Parse 'to' mapping */
 284                 t = cp++;
 285                 while (!rtld_isspace(*cp) && !iseol(*cp)) cp++;
 286
 287                 /* Skip and zero out the trailing whitespace */
 288                 while (rtld_isspace(*cp)) *cp++ = '\0';
 289
 290                 /* Should be no extra tokens at this point */
 291                 if (!iseol(*cp)) continue;
 292
 293                 *cp = '\0';
 294                 if (strcmp(f, "includedir") == 0)
 295                         lmc_parse_dir(t);
 296                 else if (strcmp(f, "include") == 0)
 297                         lmc_parse_file(t);
 298                 else
 299                         lm_add(p, f, t);
 300         }
 301 }
 302
 303 static void
 304 lm_free (struct lm_list *lml)
 305 {
 306         struct lm *lm;
 307
 308         dbg("%s(%p)", __func__, lml);
 309
 310         while (!TAILQ_EMPTY(lml)) {
 311                 lm = TAILQ_FIRST(lml);
 312                 TAILQ_REMOVE(lml, lm, lm_link);
 313                 free(lm->f);
 314                 free(lm->t);
 315                 free(lm);
 316         }
 317         return;
 318 }
 319
 320 void
 321 lm_fini (void)
 322 {
 323         struct lmp *lmp;
 324         struct lmc *p;
 325
 326         dbg("%s()", __func__);
 327
 328         while (!TAILQ_EMPTY(&lmc_head)) {
 329                 p = TAILQ_FIRST(&lmc_head);
 330                 TAILQ_REMOVE(&lmc_head, p, next);
 331                 free(p->path);
 332                 free(p);
 333         }
 334
 335         while (!TAILQ_EMPTY(&lmp_head)) {
 336                 lmp = TAILQ_FIRST(&lmp_head);
 337                 TAILQ_REMOVE(&lmp_head, lmp, lmp_link);
 338                 free(lmp->p);
 339                 lm_free(&lmp->lml);
 340                 free(lmp);
 341         }
 342         return;
 343 }
 344
 345 static void
 346 lm_add (const char *p, const char *f, const char *t)
 347 {
 348         struct lm_list *lml;
 349         struct lm *lm;
 350
 351         if (p == NULL)
 352                 p = "$DEFAULT$";
 353
 354         dbg("%s(\"%s\", \"%s\", \"%s\")", __func__, p, f, t);
 355
 356         if ((lml = lmp_find(p)) == NULL)
 357                 lml = lmp_init(xstrdup(p));
 358
 359         lm = xmalloc(sizeof(struct lm));
 360         lm->f = xstrdup(f);
 361         lm->t = xstrdup(t);
 362         TAILQ_INSERT_HEAD(lml, lm, lm_link);
 363         lm_count++;
 364 }
 365
 366 char *
 367 lm_find (const char *p, const char *f)
 368 {
 369         struct lm_list *lml;
 370         char *t;
 371
 372         dbg("%s(\"%s\", \"%s\")", __func__, p, f);
 373
 374         if (p != NULL && (lml = lmp_find(p)) != NULL) {
 375                 t = lml_find(lml, f);
 376                 if (t != NULL) {
 377                         /*
 378                          * Add a global mapping if we have
 379                          * a successful constrained match.
 380                          */
 381                         lm_add(NULL, f, t);
 382                         return (t);
 383                 }
 384         }
 385         lml = lmp_find("$DEFAULT$");
 386         if (lml != NULL)
 387                 return (lml_find(lml, f));
 388         else
 389                 return (NULL);
 390 }
 391
 392 /* Given a libmap translation list and a library name, return the
 393    replacement library, or NULL */
 394 char *
 395 lm_findn (const char *p, const char *f, const int n)
 396 {
 397         char pathbuf[64], *s, *t;
 398
 399         if (n < sizeof(pathbuf) - 1)
 400                 s = pathbuf;
 401         else
 402                 s = xmalloc(n + 1);
 403         memcpy(s, f, n);
 404         s[n] = '\0';
 405         t = lm_find(p, s);
 406         if (s != pathbuf)
 407                 free(s);
 408         return (t);
 409 }
 410
 411 static char *
 412 lml_find (struct lm_list *lmh, const char *f)
 413 {
 414         struct lm *lm;
 415
 416         dbg("%s(%p, \"%s\")", __func__, lmh, f);
 417
 418         TAILQ_FOREACH(lm, lmh, lm_link)
 419                 if (strcmp(f, lm->f) == 0)
 420                         return (lm->t);
 421         return (NULL);
 422 }
 423
 424 /* Given an executable name, return a pointer to the translation list or
 425    NULL if no matches */
 426 static struct lm_list *
 427 lmp_find (const char *n)
 428 {
 429         struct lmp *lmp;
 430
 431         dbg("%s(\"%s\")", __func__, n);
 432
 433         TAILQ_FOREACH(lmp, &lmp_head, lmp_link)
 434                 if ((lmp->type == T_EXACT && strcmp(n, lmp->p) == 0) ||
 435                     (lmp->type == T_DIRECTORY && strncmp(n, lmp->p, strlen(lmp->p)) == 0) ||
 436                     (lmp->type == T_BASENAME && strcmp(quickbasename(n), lmp->p) == 0))
 437                         return (&lmp->lml);
 438         return (NULL);
 439 }
 440
 441 static struct lm_list *
 442 lmp_init (char *n)
 443 {
 444         struct lmp *lmp;
 445
 446         dbg("%s(\"%s\")", __func__, n);
 447
 448         lmp = xmalloc(sizeof(struct lmp));
 449         lmp->p = n;
 450         if (n[strlen(n)-1] == '/')
 451                 lmp->type = T_DIRECTORY;
 452         else if (strchr(n,'/') == NULL)
 453                 lmp->type = T_BASENAME;
 454         else
 455                 lmp->type = T_EXACT;
 456         TAILQ_INIT(&lmp->lml);
 457         TAILQ_INSERT_HEAD(&lmp_head, lmp, lmp_link);
 458
 459         return (&lmp->lml);
 460 }
 461
 462 /* libc basename is overkill.  Return a pointer to the character after the
 463    last /, or the original string if there are no slashes. */
 464 static const char *
 465 quickbasename (const char *path)
 466 {
 467         const char *p = path;
 468         for (; *path; path++) {
 469                 if (*path == '/')
 470                         p = path+1;
 471         }
 472         return (p);
 473 }