nsz Git - musl/blob - src/ldso/dynlink.c

   1 #define _GNU_SOURCE
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <unistd.h>
   6 #include <stdint.h>
   7 #include <elf.h>
   8 #include <sys/mman.h>
   9 #include <limits.h>
  10 #include <stdint.h>
  11 #include <fcntl.h>
  12 #include <sys/stat.h>
  13 #include <errno.h>
  14 #include <limits.h>
  15 #include <elf.h>
  16 #include <link.h>
  17 #include <setjmp.h>
  18 #include <pthread.h>
  19 #include <ctype.h>
  20 #include <dlfcn.h>
  21 #include "pthread_impl.h"
  22 #include "libc.h"
  23
  24 static int errflag;
  25 static char errbuf[128];
  26
  27 #ifdef SHARED
  28
  29 #if ULONG_MAX == 0xffffffff
  30 typedef Elf32_Ehdr Ehdr;
  31 typedef Elf32_Phdr Phdr;
  32 typedef Elf32_Sym Sym;
  33 #define R_TYPE(x) ((x)&255)
  34 #define R_SYM(x) ((x)>>8)
  35 #else
  36 typedef Elf64_Ehdr Ehdr;
  37 typedef Elf64_Phdr Phdr;
  38 typedef Elf64_Sym Sym;
  39 #define R_TYPE(x) ((x)&0xffffffff)
  40 #define R_SYM(x) ((x)>>32)
  41 #endif
  42
  43 #define MAXP2(a,b) (-(-(a)&-(b)))
  44 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  45
  46 struct debug {
  47         int ver;
  48         void *head;
  49         void (*bp)(void);
  50         int state;
  51         void *base;
  52 };
  53
  54 struct dso {
  55         unsigned char *base;
  56         char *name;
  57         size_t *dynv;
  58         struct dso *next, *prev;
  59
  60         Phdr *phdr;
  61         int phnum;
  62         int refcnt;
  63         Sym *syms;
  64         uint32_t *hashtab;
  65         uint32_t *ghashtab;
  66         char *strings;
  67         unsigned char *map;
  68         size_t map_len;
  69         dev_t dev;
  70         ino_t ino;
  71         signed char global;
  72         char relocated;
  73         char constructed;
  74         struct dso **deps;
  75         void *tls_image;
  76         size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
  77         void **new_dtv;
  78         unsigned char *new_tls;
  79         int new_dtv_idx, new_tls_idx;
  80         struct dso *fini_next;
  81         char *shortname;
  82         char buf[];
  83 };
  84
  85 struct symdef {
  86         Sym *sym;
  87         struct dso *dso;
  88 };
  89
  90 #include "reloc.h"
  91
  92 void __init_ssp(size_t *);
  93 void *__install_initial_tls(void *);
  94
  95 static struct dso *head, *tail, *ldso, *fini_head;
  96 static char *env_path, *sys_path, *r_path;
  97 static unsigned long long gencnt;
  98 static int ssp_used;
  99 static int runtime;
 100 static int ldd_mode;
 101 static int ldso_fail;
 102 static jmp_buf rtld_fail;
 103 static pthread_rwlock_t lock;
 104 static struct debug debug;
 105 static size_t *auxv;
 106 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
 107 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 108
 109 struct debug *_dl_debug_addr = &debug;
 110
 111 #define AUX_CNT 38
 112 #define DYN_CNT 34
 113
 114 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 115 {
 116         memset(a, 0, cnt*sizeof(size_t));
 117         for (; v[0]; v+=2) if (v[0]<cnt) {
 118                 a[0] |= 1ULL<<v[0];
 119                 a[v[0]] = v[1];
 120         }
 121 }
 122
 123 static int search_vec(size_t *v, size_t *r, size_t key)
 124 {
 125         for (; v[0]!=key; v+=2)
 126                 if (!v[0]) return 0;
 127         *r = v[1];
 128         return 1;
 129 }
 130
 131 static uint32_t sysv_hash(const char *s0)
 132 {
 133         const unsigned char *s = (void *)s0;
 134         uint_fast32_t h = 0;
 135         while (*s) {
 136                 h = 16*h + *s++;
 137                 h ^= h>>24 & 0xf0;
 138         }
 139         return h & 0xfffffff;
 140 }
 141
 142 static uint32_t gnu_hash(const char *s0)
 143 {
 144         const unsigned char *s = (void *)s0;
 145         uint_fast32_t h = 5381;
 146         for (; *s; s++)
 147                 h = h*33 + *s;
 148         return h;
 149 }
 150
 151 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 152 {
 153         size_t i;
 154         Sym *syms = dso->syms;
 155         uint32_t *hashtab = dso->hashtab;
 156         char *strings = dso->strings;
 157         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 158                 if (!strcmp(s, strings+syms[i].st_name))
 159                         return syms+i;
 160         }
 161         return 0;
 162 }
 163
 164 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 165 {
 166         Sym *sym;
 167         char *strings;
 168         uint32_t *hashtab = dso->ghashtab;
 169         uint32_t nbuckets = hashtab[0];
 170         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 171         uint32_t h2;
 172         uint32_t *hashval;
 173         uint32_t n = buckets[h1 % nbuckets];
 174
 175         if (!n) return 0;
 176
 177         strings = dso->strings;
 178         sym = dso->syms + n;
 179         hashval = buckets + nbuckets + (n - hashtab[1]);
 180
 181         for (h1 |= 1; ; sym++) {
 182                 h2 = *hashval++;
 183                 if ((h1 == (h2|1)) && !strcmp(s, strings + sym->st_name))
 184                         return sym;
 185                 if (h2 & 1) break;
 186         }
 187
 188         return 0;
 189 }
 190
 191 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 192 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK)
 193
 194 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 195 {
 196         uint32_t h = 0, gh = 0;
 197         struct symdef def = {0};
 198         if (dso->ghashtab) {
 199                 gh = gnu_hash(s);
 200                 if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 201         } else {
 202                 h = sysv_hash(s);
 203                 if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 204         }
 205         for (; dso; dso=dso->next) {
 206                 Sym *sym;
 207                 if (!dso->global) continue;
 208                 if (dso->ghashtab) {
 209                         if (!gh) gh = gnu_hash(s);
 210                         sym = gnu_lookup(s, gh, dso);
 211                 } else {
 212                         if (!h) h = sysv_hash(s);
 213                         sym = sysv_lookup(s, h, dso);
 214                 }
 215                 if (!sym) continue;
 216                 if (!sym->st_shndx)
 217                         if (need_def || (sym->st_info&0xf) == STT_TLS)
 218                                 continue;
 219                 if (!sym->st_value)
 220                         if ((sym->st_info&0xf) != STT_TLS)
 221                                 continue;
 222                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 223                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 224
 225                 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
 226                 def.sym = sym;
 227                 def.dso = dso;
 228                 if (sym->st_info>>4 == STB_GLOBAL) break;
 229         }
 230         return def;
 231 }
 232
 233 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 234 {
 235         unsigned char *base = dso->base;
 236         Sym *syms = dso->syms;
 237         char *strings = dso->strings;
 238         Sym *sym;
 239         const char *name;
 240         void *ctx;
 241         int type;
 242         int sym_index;
 243         struct symdef def;
 244
 245         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 246                 type = R_TYPE(rel[1]);
 247                 sym_index = R_SYM(rel[1]);
 248                 if (sym_index) {
 249                         sym = syms + sym_index;
 250                         name = strings + sym->st_name;
 251                         ctx = IS_COPY(type) ? head->next : head;
 252                         def = find_sym(ctx, name, IS_PLT(type));
 253                         if (!def.sym && sym->st_info>>4 != STB_WEAK) {
 254                                 snprintf(errbuf, sizeof errbuf,
 255                                         "Error relocating %s: %s: symbol not found",
 256                                         dso->name, name);
 257                                 if (runtime) longjmp(rtld_fail, 1);
 258                                 dprintf(2, "%s\n", errbuf);
 259                                 ldso_fail = 1;
 260                                 continue;
 261                         }
 262                 } else {
 263                         sym = 0;
 264                         def.sym = 0;
 265                         def.dso = 0;
 266                 }
 267                 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
 268                         stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
 269                         def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
 270         }
 271 }
 272
 273 /* A huge hack: to make up for the wastefulness of shared libraries
 274  * needing at least a page of dirty memory even if they have no global
 275  * data, we reclaim the gaps at the beginning and end of writable maps
 276  * and "donate" them to the heap by setting up minimal malloc
 277  * structures and then freeing them. */
 278
 279 static void reclaim(unsigned char *base, size_t start, size_t end)
 280 {
 281         size_t *a, *z;
 282         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 283         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 284         if (start>end || end-start < 4*sizeof(size_t)) return;
 285         a = (size_t *)(base + start);
 286         z = (size_t *)(base + end);
 287         a[-2] = 1;
 288         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 289         z[1] = 1;
 290         free(a);
 291 }
 292
 293 static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phcnt)
 294 {
 295         for (; phcnt--; ph=(void *)((char *)ph+phent)) {
 296                 if (ph->p_type!=PT_LOAD) continue;
 297                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 298                 reclaim(base, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 299                 reclaim(base, ph->p_vaddr+ph->p_memsz,
 300                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 301         }
 302 }
 303
 304 static void *map_library(int fd, struct dso *dso)
 305 {
 306         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 307         size_t phsize;
 308         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 309         size_t this_min, this_max;
 310         off_t off_start;
 311         Ehdr *eh;
 312         Phdr *ph;
 313         unsigned prot;
 314         unsigned char *map, *base;
 315         size_t dyn;
 316         size_t tls_image=0;
 317         size_t i;
 318
 319         ssize_t l = read(fd, buf, sizeof buf);
 320         if (l<sizeof *eh) return 0;
 321         eh = buf;
 322         phsize = eh->e_phentsize * eh->e_phnum;
 323         if (phsize + sizeof *eh > l) return 0;
 324         if (eh->e_phoff + phsize > l) {
 325                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 326                 if (l != phsize) return 0;
 327                 eh->e_phoff = sizeof *eh;
 328         }
 329         ph = (void *)((char *)buf + eh->e_phoff);
 330         dso->phdr = ph;
 331         dso->phnum = eh->e_phnum;
 332         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 333                 if (ph->p_type == PT_DYNAMIC)
 334                         dyn = ph->p_vaddr;
 335                 if (ph->p_type == PT_TLS) {
 336                         tls_image = ph->p_vaddr;
 337                         dso->tls_align = ph->p_align;
 338                         dso->tls_len = ph->p_filesz;
 339                         dso->tls_size = ph->p_memsz;
 340                 }
 341                 if (ph->p_type != PT_LOAD) continue;
 342                 if (ph->p_vaddr < addr_min) {
 343                         addr_min = ph->p_vaddr;
 344                         off_start = ph->p_offset;
 345                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 346                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 347                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 348                 }
 349                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 350                         addr_max = ph->p_vaddr+ph->p_memsz;
 351                 }
 352         }
 353         if (!dyn) return 0;
 354         addr_max += PAGE_SIZE-1;
 355         addr_max &= -PAGE_SIZE;
 356         addr_min &= -PAGE_SIZE;
 357         off_start &= -PAGE_SIZE;
 358         map_len = addr_max - addr_min + off_start;
 359         /* The first time, we map too much, possibly even more than
 360          * the length of the file. This is okay because we will not
 361          * use the invalid part; we just need to reserve the right
 362          * amount of virtual address space to map over later. */
 363         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 364         if (map==MAP_FAILED) return 0;
 365         base = map - addr_min;
 366         ph = (void *)((char *)buf + eh->e_phoff);
 367         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 368                 if (ph->p_type != PT_LOAD) continue;
 369                 /* Reuse the existing mapping for the lowest-address LOAD */
 370                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 371                 this_min = ph->p_vaddr & -PAGE_SIZE;
 372                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 373                 off_start = ph->p_offset & -PAGE_SIZE;
 374                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 375                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 376                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 377                 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 378                         goto error;
 379                 if (ph->p_memsz > ph->p_filesz) {
 380                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 381                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 382                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 383                         if (pgbrk-(size_t)base < this_max && mmap((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED)
 384                                 goto error;
 385                 }
 386         }
 387         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 388                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 389                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
 390                                 goto error;
 391                         break;
 392                 }
 393         if (!runtime) reclaim_gaps(base, (void *)((char *)buf + eh->e_phoff),
 394                 eh->e_phentsize, eh->e_phnum);
 395         dso->map = map;
 396         dso->map_len = map_len;
 397         dso->base = base;
 398         dso->dynv = (void *)(base+dyn);
 399         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 400         return map;
 401 error:
 402         munmap(map, map_len);
 403         return 0;
 404 }
 405
 406 static int path_open(const char *name, const char *search, char *buf, size_t buf_size)
 407 {
 408         const char *s=search, *z;
 409         int l, fd;
 410         for (;;) {
 411                 while (*s==':') s++;
 412                 if (!*s) return -1;
 413                 z = strchr(s, ':');
 414                 l = z ? z-s : strlen(s);
 415                 snprintf(buf, buf_size, "%.*s/%s", l, s, name);
 416                 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 417                 s += l;
 418         }
 419 }
 420
 421 static void decode_dyn(struct dso *p)
 422 {
 423         size_t dyn[DYN_CNT] = {0};
 424         decode_vec(p->dynv, dyn, DYN_CNT);
 425         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 426         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 427         if (dyn[0]&(1<<DT_HASH))
 428                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 429         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 430                 p->ghashtab = (void *)(p->base + *dyn);
 431 }
 432
 433 static struct dso *load_library(const char *name)
 434 {
 435         char buf[2*NAME_MAX+2];
 436         const char *pathname;
 437         unsigned char *base, *map;
 438         size_t dyno, map_len;
 439         struct dso *p, temp_dso = {0};
 440         int fd;
 441         struct stat st;
 442         size_t alloc_size;
 443         int n_th = 0;
 444
 445         /* Catch and block attempts to reload the implementation itself */
 446         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 447                 static const char *rp, reserved[] =
 448                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 449                 char *z = strchr(name, '.');
 450                 if (z) {
 451                         size_t l = z-name;
 452                         for (rp=reserved; *rp && memcmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 453                         if (*rp) {
 454                                 if (!ldso->prev) {
 455                                         tail->next = ldso;
 456                                         ldso->prev = tail;
 457                                         tail = ldso->next ? ldso->next : ldso;
 458                                 }
 459                                 return ldso;
 460                         }
 461                 }
 462         }
 463         if (strchr(name, '/')) {
 464                 pathname = name;
 465                 fd = open(name, O_RDONLY|O_CLOEXEC);
 466         } else {
 467                 /* Search for the name to see if it's already loaded */
 468                 for (p=head->next; p; p=p->next) {
 469                         if (p->shortname && !strcmp(p->shortname, name)) {
 470                                 p->refcnt++;
 471                                 return p;
 472                         }
 473                 }
 474                 if (strlen(name) > NAME_MAX) return 0;
 475                 fd = -1;
 476                 if (r_path) fd = path_open(name, r_path, buf, sizeof buf);
 477                 if (fd < 0 && env_path) fd = path_open(name, env_path, buf, sizeof buf);
 478                 if (fd < 0) {
 479                         if (!sys_path) {
 480                                 FILE *f = fopen(ETC_LDSO_PATH, "rbe");
 481                                 if (f) {
 482                                         if (getline(&sys_path, (size_t[1]){0}, f) > 0)
 483                                                 sys_path[strlen(sys_path)-1]=0;
 484                                         fclose(f);
 485                                 }
 486                         }
 487                         if (sys_path) fd = path_open(name, sys_path, buf, sizeof buf);
 488                         else fd = path_open(name, "/lib:/usr/local/lib:/usr/lib", buf, sizeof buf);
 489                 }
 490                 pathname = buf;
 491         }
 492         if (fd < 0) return 0;
 493         if (fstat(fd, &st) < 0) {
 494                 close(fd);
 495                 return 0;
 496         }
 497         for (p=head->next; p; p=p->next) {
 498                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 499                         /* If this library was previously loaded with a
 500                          * pathname but a search found the same inode,
 501                          * setup its shortname so it can be found by name. */
 502                         if (!p->shortname && pathname != name)
 503                                 p->shortname = strrchr(p->name, '/')+1;
 504                         close(fd);
 505                         p->refcnt++;
 506                         return p;
 507                 }
 508         }
 509         map = map_library(fd, &temp_dso);
 510         close(fd);
 511         if (!map) return 0;
 512
 513         /* Allocate storage for the new DSO. When there is TLS, this
 514          * storage must include a reservation for all pre-existing
 515          * threads to obtain copies of both the new TLS, and an
 516          * extended DTV capable of storing an additional slot for
 517          * the newly-loaded DSO. */
 518         alloc_size = sizeof *p + strlen(pathname) + 1;
 519         if (runtime && temp_dso.tls_image) {
 520                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 521                         + sizeof(void *) * (tls_cnt+3);
 522                 n_th = libc.threads_minus_1 + 1;
 523                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 524                 else alloc_size += n_th * per_th;
 525         }
 526         p = calloc(1, alloc_size);
 527         if (!p) {
 528                 munmap(map, map_len);
 529                 return 0;
 530         }
 531         memcpy(p, &temp_dso, sizeof temp_dso);
 532         decode_dyn(p);
 533         p->dev = st.st_dev;
 534         p->ino = st.st_ino;
 535         p->refcnt = 1;
 536         p->name = p->buf;
 537         strcpy(p->name, pathname);
 538         /* Add a shortname only if name arg was not an explicit pathname. */
 539         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 540         if (p->tls_image) {
 541                 if (runtime && !__pthread_self_init()) {
 542                         free(p);
 543                         munmap(map, map_len);
 544                         return 0;
 545                 }
 546                 p->tls_id = ++tls_cnt;
 547                 tls_align = MAXP2(tls_align, p->tls_align);
 548 #ifdef TLS_ABOVE_TP
 549                 p->tls_offset = tls_offset + ( (tls_align-1) &
 550                         -(tls_offset + (uintptr_t)p->tls_image) );
 551                 tls_offset += p->tls_size;
 552 #else
 553                 tls_offset += p->tls_size + p->tls_align - 1;
 554                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 555                         & (p->tls_align-1);
 556                 p->tls_offset = tls_offset;
 557 #endif
 558                 p->new_dtv = (void *)(-sizeof(size_t) &
 559                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 560                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 561         }
 562
 563         tail->next = p;
 564         p->prev = tail;
 565         tail = p;
 566
 567         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, base);
 568
 569         return p;
 570 }
 571
 572 static void load_deps(struct dso *p)
 573 {
 574         size_t i, ndeps=0;
 575         struct dso ***deps = &p->deps, **tmp, *dep;
 576         for (; p; p=p->next) {
 577                 for (i=0; p->dynv[i]; i+=2) {
 578                         if (p->dynv[i] != DT_RPATH) continue;
 579                         r_path = (void *)(p->strings + p->dynv[i+1]);
 580                 }
 581                 for (i=0; p->dynv[i]; i+=2) {
 582                         if (p->dynv[i] != DT_NEEDED) continue;
 583                         dep = load_library(p->strings + p->dynv[i+1]);
 584                         if (!dep) {
 585                                 snprintf(errbuf, sizeof errbuf,
 586                                         "Error loading shared library %s: %m (needed by %s)",
 587                                         p->strings + p->dynv[i+1], p->name);
 588                                 if (runtime) longjmp(rtld_fail, 1);
 589                                 dprintf(2, "%s\n", errbuf);
 590                                 ldso_fail = 1;
 591                                 continue;
 592                         }
 593                         if (runtime) {
 594                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 595                                 if (!tmp) longjmp(rtld_fail, 1);
 596                                 tmp[ndeps++] = dep;
 597                                 tmp[ndeps] = 0;
 598                                 *deps = tmp;
 599                         }
 600                 }
 601                 r_path = 0;
 602         }
 603 }
 604
 605 static void load_preload(char *s)
 606 {
 607         int tmp;
 608         char *z;
 609         for (z=s; *z; s=z) {
 610                 for (   ; *s && isspace(*s); s++);
 611                 for (z=s; *z && !isspace(*z); z++);
 612                 tmp = *z;
 613                 *z = 0;
 614                 load_library(s);
 615                 *z = tmp;
 616         }
 617 }
 618
 619 static void make_global(struct dso *p)
 620 {
 621         for (; p; p=p->next) p->global = 1;
 622 }
 623
 624 static void reloc_all(struct dso *p)
 625 {
 626         size_t dyn[DYN_CNT] = {0};
 627         for (; p; p=p->next) {
 628                 if (p->relocated) continue;
 629                 decode_vec(p->dynv, dyn, DYN_CNT);
 630 #ifdef NEED_ARCH_RELOCS
 631                 do_arch_relocs(p, head);
 632 #endif
 633                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 634                         2+(dyn[DT_PLTREL]==DT_RELA));
 635                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 636                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 637                 p->relocated = 1;
 638         }
 639 }
 640
 641 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
 642 {
 643         for (; cnt--; ph = (void *)((char *)ph + stride))
 644                 if (ph->p_type == PT_DYNAMIC)
 645                         return ph->p_vaddr;
 646         return 0;
 647 }
 648
 649 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
 650 {
 651         size_t min_addr = -1, max_addr = 0;
 652         for (; cnt--; ph = (void *)((char *)ph + stride)) {
 653                 if (ph->p_type != PT_LOAD) continue;
 654                 if (ph->p_vaddr < min_addr)
 655                         min_addr = ph->p_vaddr;
 656                 if (ph->p_vaddr+ph->p_memsz > max_addr)
 657                         max_addr = ph->p_vaddr+ph->p_memsz;
 658         }
 659         min_addr &= -PAGE_SIZE;
 660         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
 661         p->map = p->base + min_addr;
 662         p->map_len = max_addr - min_addr;
 663 }
 664
 665 static void do_fini()
 666 {
 667         struct dso *p;
 668         size_t dyn[DYN_CNT] = {0};
 669         for (p=fini_head; p; p=p->fini_next) {
 670                 if (!p->constructed) continue;
 671                 decode_vec(p->dynv, dyn, DYN_CNT);
 672                 ((void (*)(void))(p->base + dyn[DT_FINI]))();
 673         }
 674 }
 675
 676 static void do_init_fini(struct dso *p)
 677 {
 678         size_t dyn[DYN_CNT] = {0};
 679         int need_locking = libc.threads_minus_1;
 680         /* Allow recursive calls that arise when a library calls
 681          * dlopen from one of its constructors, but block any
 682          * other threads until all ctors have finished. */
 683         if (need_locking) pthread_mutex_lock(&init_fini_lock);
 684         for (; p; p=p->prev) {
 685                 if (p->constructed) continue;
 686                 p->constructed = 1;
 687                 decode_vec(p->dynv, dyn, DYN_CNT);
 688                 if (dyn[0] & (1<<DT_FINI)) {
 689                         p->fini_next = fini_head;
 690                         fini_head = p;
 691                 }
 692                 if (dyn[0] & (1<<DT_INIT))
 693                         ((void (*)(void))(p->base + dyn[DT_INIT]))();
 694         }
 695         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
 696 }
 697
 698 void _dl_debug_state(void)
 699 {
 700 }
 701
 702 void *__copy_tls(unsigned char *mem)
 703 {
 704         pthread_t td;
 705         struct dso *p;
 706
 707         if (!tls_cnt) return mem;
 708
 709         void **dtv = (void *)mem;
 710         dtv[0] = (void *)tls_cnt;
 711
 712 #ifdef TLS_ABOVE_TP
 713         mem += sizeof(void *) * (tls_cnt+1);
 714         mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
 715         td = (pthread_t)mem;
 716         mem += sizeof(struct pthread);
 717
 718         for (p=head; p; p=p->next) {
 719                 if (!p->tls_id) continue;
 720                 dtv[p->tls_id] = mem + p->tls_offset;
 721                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 722         }
 723 #else
 724         mem += libc.tls_size - sizeof(struct pthread);
 725         mem -= (uintptr_t)mem & (tls_align-1);
 726         td = (pthread_t)mem;
 727
 728         for (p=head; p; p=p->next) {
 729                 if (!p->tls_id) continue;
 730                 dtv[p->tls_id] = mem - p->tls_offset;
 731                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 732         }
 733 #endif
 734         td->dtv = dtv;
 735         return td;
 736 }
 737
 738 void *__tls_get_addr(size_t *v)
 739 {
 740         pthread_t self = __pthread_self();
 741         if (self->dtv && v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
 742                 return (char *)self->dtv[v[0]]+v[1];
 743
 744         /* Block signals to make accessing new TLS async-signal-safe */
 745         sigset_t set;
 746         pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
 747         if (self->dtv && v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
 748                 pthread_sigmask(SIG_SETMASK, &set, 0);
 749                 return (char *)self->dtv[v[0]]+v[1];
 750         }
 751
 752         /* This is safe without any locks held because, if the caller
 753          * is able to request the Nth entry of the DTV, the DSO list
 754          * must be valid at least that far out and it was synchronized
 755          * at program startup or by an already-completed call to dlopen. */
 756         struct dso *p;
 757         for (p=head; p->tls_id != v[0]; p=p->next);
 758
 759         /* Get new DTV space from new DSO if needed */
 760         if (!self->dtv || v[0] > (size_t)self->dtv[0]) {
 761                 void **newdtv = p->new_dtv +
 762                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
 763                 if (self->dtv) memcpy(newdtv, self->dtv,
 764                         ((size_t)self->dtv[0]+1) * sizeof(void *));
 765                 newdtv[0] = (void *)v[0];
 766                 self->dtv = newdtv;
 767         }
 768
 769         /* Get new TLS memory from new DSO */
 770         unsigned char *mem = p->new_tls +
 771                 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
 772         mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
 773         self->dtv[v[0]] = mem;
 774         memcpy(mem, p->tls_image, p->tls_len);
 775         pthread_sigmask(SIG_SETMASK, &set, 0);
 776         return mem + v[1];
 777 }
 778
 779 static void update_tls_size()
 780 {
 781         libc.tls_size = ALIGN(
 782                 (1+tls_cnt) * sizeof(void *) +
 783                 tls_offset +
 784                 sizeof(struct pthread) +
 785                 tls_align * 2,
 786         tls_align);
 787 }
 788
 789 void *__dynlink(int argc, char **argv)
 790 {
 791         size_t aux[AUX_CNT] = {0};
 792         size_t i;
 793         Phdr *phdr;
 794         Ehdr *ehdr;
 795         static struct dso builtin_dsos[3];
 796         struct dso *const app = builtin_dsos+0;
 797         struct dso *const lib = builtin_dsos+1;
 798         struct dso *const vdso = builtin_dsos+2;
 799         char *env_preload=0;
 800         size_t vdso_base;
 801
 802         /* Find aux vector just past environ[] */
 803         for (i=argc+1; argv[i]; i++)
 804                 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
 805                         env_path = argv[i]+16;
 806                 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
 807                         env_preload = argv[i]+11;
 808         auxv = (void *)(argv+i+1);
 809
 810         decode_vec(auxv, aux, AUX_CNT);
 811
 812         /* Only trust user/env if kernel says we're not suid/sgid */
 813         if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
 814           || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
 815                 env_path = 0;
 816                 env_preload = 0;
 817         }
 818
 819         /* If the dynamic linker was invoked as a program itself, AT_BASE
 820          * will not be set. In that case, we assume the base address is
 821          * the start of the page containing the PHDRs; I don't know any
 822          * better approach... */
 823         if (!aux[AT_BASE]) {
 824                 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
 825                 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
 826         }
 827
 828         /* The dynamic linker load address is passed by the kernel
 829          * in the AUX vector, so this is easy. */
 830         lib->base = (void *)aux[AT_BASE];
 831         lib->name = lib->shortname = "libc.so";
 832         lib->global = 1;
 833         ehdr = (void *)lib->base;
 834         lib->phnum = ehdr->e_phnum;
 835         lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
 836         find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
 837         lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
 838                     ehdr->e_phnum, ehdr->e_phentsize));
 839         decode_dyn(lib);
 840
 841         if (aux[AT_PHDR]) {
 842                 size_t interp_off = 0;
 843                 size_t tls_image = 0;
 844                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
 845                 app->phdr = phdr = (void *)aux[AT_PHDR];
 846                 app->phnum = aux[AT_PHNUM];
 847                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
 848                         if (phdr->p_type == PT_PHDR)
 849                                 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
 850                         else if (phdr->p_type == PT_INTERP)
 851                                 interp_off = (size_t)phdr->p_vaddr;
 852                         else if (phdr->p_type == PT_TLS) {
 853                                 tls_image = phdr->p_vaddr;
 854                                 app->tls_len = phdr->p_filesz;
 855                                 app->tls_size = phdr->p_memsz;
 856                                 app->tls_align = phdr->p_align;
 857                         }
 858                 }
 859                 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
 860                 if (interp_off) lib->name = (char *)app->base + interp_off;
 861                 app->name = argv[0];
 862                 app->dynv = (void *)(app->base + find_dyn(
 863                         (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
 864                 find_map_range((void *)aux[AT_PHDR],
 865                         aux[AT_PHNUM], aux[AT_PHENT], app);
 866         } else {
 867                 int fd;
 868                 char *ldname = argv[0];
 869                 size_t dyno, l = strlen(ldname);
 870                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
 871                 *argv++ = (void *)-1;
 872                 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
 873                 if (!argv[0]) {
 874                         dprintf(2, "musl libc/dynamic program loader\n");
 875                         dprintf(2, "usage: %s pathname%s\n", ldname,
 876                                 ldd_mode ? "" : " [args]");
 877                         _exit(1);
 878                 }
 879                 fd = open(argv[0], O_RDONLY);
 880                 if (fd < 0) {
 881                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
 882                         _exit(1);
 883                 }
 884                 runtime = 1;
 885                 ehdr = (void *)map_library(fd, app);
 886                 if (!ehdr) {
 887                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
 888                         _exit(1);
 889                 }
 890                 runtime = 0;
 891                 close(fd);
 892                 lib->name = ldname;
 893                 app->name = argv[0];
 894                 app->phnum = ehdr->e_phnum;
 895                 app->phdr = (void *)(app->base + ehdr->e_phoff);
 896                 aux[AT_ENTRY] = ehdr->e_entry;
 897         }
 898         if (app->tls_size) {
 899                 app->tls_id = tls_cnt = 1;
 900 #ifdef TLS_ABOVE_TP
 901                 app->tls_offset = 0;
 902                 tls_offset = app->tls_size
 903                         + ( -((uintptr_t)app->tls_image + app->tls_size)
 904                         & (app->tls_align-1) );
 905 #else
 906                 tls_offset = app->tls_offset = app->tls_size
 907                         + ( -((uintptr_t)app->tls_image + app->tls_size)
 908                         & (app->tls_align-1) );
 909 #endif
 910                 tls_align = MAXP2(tls_align, app->tls_align);
 911         }
 912         app->global = 1;
 913         app->constructed = 1;
 914         decode_dyn(app);
 915
 916         /* Attach to vdso, if provided by the kernel */
 917         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
 918                 ehdr = (void *)vdso_base;
 919                 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
 920                 vdso->phnum = ehdr->e_phnum;
 921                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
 922                         if (phdr->p_type == PT_DYNAMIC)
 923                                 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
 924                         if (phdr->p_type == PT_LOAD)
 925                                 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
 926                 }
 927                 vdso->name = vdso->shortname = "linux-gate.so.1";
 928                 vdso->global = 1;
 929                 decode_dyn(vdso);
 930                 vdso->prev = lib;
 931                 lib->next = vdso;
 932         }
 933
 934         /* Initial dso chain consists only of the app. We temporarily
 935          * append the dynamic linker/libc so we can relocate it, then
 936          * restore the initial chain in preparation for loading third
 937          * party libraries (preload/needed). */
 938         head = tail = app;
 939         ldso = lib;
 940         app->next = lib;
 941         reloc_all(lib);
 942         app->next = 0;
 943
 944         /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
 945
 946         /* Donate unused parts of app and library mapping to malloc */
 947         reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
 948         ehdr = (void *)lib->base;
 949         reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
 950                 ehdr->e_phentsize, ehdr->e_phnum);
 951
 952         /* Load preload/needed libraries, add their symbols to the global
 953          * namespace, and perform all remaining relocations. The main
 954          * program must be relocated LAST since it may contain copy
 955          * relocations which depend on libraries' relocations. */
 956         if (env_preload) load_preload(env_preload);
 957         load_deps(app);
 958         make_global(app);
 959
 960         reloc_all(app->next);
 961         reloc_all(app);
 962
 963         update_tls_size();
 964         if (tls_cnt) {
 965                 struct dso *p;
 966                 void *mem = mmap(0, libc.tls_size, PROT_READ|PROT_WRITE,
 967                         MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
 968                 if (mem==MAP_FAILED ||
 969                     !__install_initial_tls(__copy_tls(mem))) {
 970                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
 971                                 argv[0], libc.tls_size);
 972                         _exit(127);
 973                 }
 974         }
 975
 976         if (ldso_fail) _exit(127);
 977         if (ldd_mode) _exit(0);
 978
 979         /* Switch to runtime mode: any further failures in the dynamic
 980          * linker are a reportable failure rather than a fatal startup
 981          * error. If the dynamic loader (dlopen) will not be used, free
 982          * all memory used by the dynamic linker. */
 983         runtime = 1;
 984
 985 #ifndef DYNAMIC_IS_RO
 986         for (i=0; app->dynv[i]; i+=2)
 987                 if (app->dynv[i]==DT_DEBUG)
 988                         app->dynv[i+1] = (size_t)&debug;
 989 #endif
 990         debug.ver = 1;
 991         debug.bp = _dl_debug_state;
 992         debug.head = head;
 993         debug.base = lib->base;
 994         debug.state = 0;
 995         _dl_debug_state();
 996
 997         if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
 998
 999         atexit(do_fini);
1000         do_init_fini(tail);
1001
1002         errno = 0;
1003         return (void *)aux[AT_ENTRY];
1004 }
1005
1006 void *dlopen(const char *file, int mode)
1007 {
1008         struct dso *volatile p, *orig_tail, *next;
1009         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1010         size_t i;
1011         int cs;
1012
1013         if (!file) return head;
1014
1015         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1016         pthread_rwlock_wrlock(&lock);
1017         __inhibit_ptc();
1018
1019         p = 0;
1020         orig_tls_cnt = tls_cnt;
1021         orig_tls_offset = tls_offset;
1022         orig_tls_align = tls_align;
1023         orig_tail = tail;
1024
1025         if (setjmp(rtld_fail)) {
1026                 /* Clean up anything new that was (partially) loaded */
1027                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1028                         if (p->deps[i]->global < 0)
1029                                 p->deps[i]->global = 0;
1030                 for (p=orig_tail->next; p; p=next) {
1031                         next = p->next;
1032                         munmap(p->map, p->map_len);
1033                         free(p->deps);
1034                         free(p);
1035                 }
1036                 tls_cnt = orig_tls_cnt;
1037                 tls_offset = orig_tls_offset;
1038                 tls_align = orig_tls_align;
1039                 tail = orig_tail;
1040                 tail->next = 0;
1041                 p = 0;
1042                 errflag = 1;
1043                 goto end;
1044         } else p = load_library(file);
1045
1046         if (!p) {
1047                 snprintf(errbuf, sizeof errbuf,
1048                         "Error loading shared library %s: %m", file);
1049                 errflag = 1;
1050                 goto end;
1051         }
1052
1053         /* First load handling */
1054         if (!p->deps) {
1055                 load_deps(p);
1056                 if (p->deps) for (i=0; p->deps[i]; i++)
1057                         if (!p->deps[i]->global)
1058                                 p->deps[i]->global = -1;
1059                 if (!p->global) p->global = -1;
1060                 reloc_all(p);
1061                 if (p->deps) for (i=0; p->deps[i]; i++)
1062                         if (p->deps[i]->global < 0)
1063                                 p->deps[i]->global = 0;
1064                 if (p->global < 0) p->global = 0;
1065         }
1066
1067         if (mode & RTLD_GLOBAL) {
1068                 if (p->deps) for (i=0; p->deps[i]; i++)
1069                         p->deps[i]->global = 1;
1070                 p->global = 1;
1071         }
1072
1073         update_tls_size();
1074
1075         if (ssp_used) __init_ssp(auxv);
1076
1077         _dl_debug_state();
1078         orig_tail = tail;
1079 end:
1080         __release_ptc();
1081         if (p) gencnt++;
1082         pthread_rwlock_unlock(&lock);
1083         if (p) do_init_fini(orig_tail);
1084         pthread_setcancelstate(cs, 0);
1085         return p;
1086 }
1087
1088 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1089 {
1090         size_t i;
1091         uint32_t h = 0, gh = 0;
1092         Sym *sym;
1093         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1094                 if (p == RTLD_DEFAULT) {
1095                         p = head;
1096                 } else if (p == RTLD_NEXT) {
1097                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1098                         if (!p) p=head;
1099                         p = p->next;
1100                 }
1101                 struct symdef def = find_sym(p, s, 0);
1102                 if (!def.sym) goto failed;
1103                 if ((def.sym->st_info&0xf) == STT_TLS)
1104                         return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1105                 return def.dso->base + def.sym->st_value;
1106         }
1107         if (p->ghashtab) {
1108                 gh = gnu_hash(s);
1109                 sym = gnu_lookup(s, gh, p);
1110         } else {
1111                 h = sysv_hash(s);
1112                 sym = sysv_lookup(s, h, p);
1113         }
1114         if (sym && (sym->st_info&0xf) == STT_TLS)
1115                 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1116         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1117                 return p->base + sym->st_value;
1118         if (p->deps) for (i=0; p->deps[i]; i++) {
1119                 if (p->deps[i]->ghashtab) {
1120                         if (!gh) gh = gnu_hash(s);
1121                         sym = gnu_lookup(s, gh, p->deps[i]);
1122                 } else {
1123                         if (!h) h = sysv_hash(s);
1124                         sym = sysv_lookup(s, h, p->deps[i]);
1125                 }
1126                 if (sym && (sym->st_info&0xf) == STT_TLS)
1127                         return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1128                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1129                         return p->deps[i]->base + sym->st_value;
1130         }
1131 failed:
1132         errflag = 1;
1133         snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1134         return 0;
1135 }
1136
1137 int __dladdr(void *addr, Dl_info *info)
1138 {
1139         struct dso *p;
1140         Sym *sym;
1141         uint32_t nsym;
1142         char *strings;
1143         size_t i;
1144         void *best = 0;
1145         char *bestname;
1146
1147         pthread_rwlock_rdlock(&lock);
1148         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1149         pthread_rwlock_unlock(&lock);
1150
1151         if (!p) return 0;
1152
1153         sym = p->syms;
1154         strings = p->strings;
1155         if (p->hashtab) {
1156                 nsym = p->hashtab[1];
1157         } else {
1158                 uint32_t *buckets;
1159                 uint32_t *hashval;
1160                 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1161                 sym += p->ghashtab[1];
1162                 for (i = 0; i < p->ghashtab[0]; i++) {
1163                         if (buckets[i] > nsym)
1164                                 nsym = buckets[i];
1165                 }
1166                 if (nsym) {
1167                         nsym -= p->ghashtab[1];
1168                         hashval = buckets + p->ghashtab[0] + nsym;
1169                         do nsym++;
1170                         while (!(*hashval++ & 1));
1171                 }
1172         }
1173
1174         for (; nsym; nsym--, sym++) {
1175                 if (sym->st_shndx && sym->st_value
1176                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1177                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1178                         void *symaddr = p->base + sym->st_value;
1179                         if (symaddr > addr || symaddr < best)
1180                                 continue;
1181                         best = symaddr;
1182                         bestname = strings + sym->st_name;
1183                         if (addr == symaddr)
1184                                 break;
1185                 }
1186         }
1187
1188         if (!best) return 0;
1189
1190         info->dli_fname = p->name;
1191         info->dli_fbase = p->base;
1192         info->dli_sname = bestname;
1193         info->dli_saddr = best;
1194
1195         return 1;
1196 }
1197
1198 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1199 {
1200         void *res;
1201         pthread_rwlock_rdlock(&lock);
1202         res = do_dlsym(p, s, ra);
1203         pthread_rwlock_unlock(&lock);
1204         return res;
1205 }
1206
1207 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1208 {
1209         struct dso *current;
1210         struct dl_phdr_info info;
1211         int ret = 0;
1212         for(current = head; current;) {
1213                 info.dlpi_addr      = (uintptr_t)current->base;
1214                 info.dlpi_name      = current->name;
1215                 info.dlpi_phdr      = current->phdr;
1216                 info.dlpi_phnum     = current->phnum;
1217                 info.dlpi_adds      = gencnt;
1218                 info.dlpi_subs      = 0;
1219                 info.dlpi_tls_modid = current->tls_id;
1220                 info.dlpi_tls_data  = current->tls_image;
1221
1222                 ret = (callback)(&info, sizeof (info), data);
1223
1224                 if (ret != 0) break;
1225
1226                 pthread_rwlock_rdlock(&lock);
1227                 current = current->next;
1228                 pthread_rwlock_unlock(&lock);
1229         }
1230         return ret;
1231 }
1232 #else
1233 void *dlopen(const char *file, int mode)
1234 {
1235         return 0;
1236 }
1237 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1238 {
1239         return 0;
1240 }
1241 int __dladdr (void *addr, Dl_info *info)
1242 {
1243         return 0;
1244 }
1245 #endif
1246
1247 char *dlerror()
1248 {
1249         if (!errflag) return 0;
1250         errflag = 0;
1251         return errbuf;
1252 }
1253
1254 int dlclose(void *p)
1255 {
1256         return 0;
1257 }