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