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