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 int noload;
 103 static jmp_buf rtld_fail;
 104 static pthread_rwlock_t lock;
 105 static struct debug debug;
 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, *ph0;
 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                 ph = ph0 = (void *)(buf + 1);
 328         } else {
 329                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 330         }
 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         dso->phdr = 0;
 366         dso->phnum = 0;
 367         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 368                 if (ph->p_type != PT_LOAD) continue;
 369                 /* Check if the programs headers are in this load segment, and
 370                  * if so, record the address for use by dl_iterate_phdr. */
 371                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 372                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 373                         dso->phdr = (void *)(base + ph->p_vaddr
 374                                 + (eh->e_phoff-ph->p_offset));
 375                         dso->phnum = eh->e_phnum;
 376                 }
 377                 /* Reuse the existing mapping for the lowest-address LOAD */
 378                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 379                 this_min = ph->p_vaddr & -PAGE_SIZE;
 380                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 381                 off_start = ph->p_offset & -PAGE_SIZE;
 382                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 383                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 384                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 385                 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 386                         goto error;
 387                 if (ph->p_memsz > ph->p_filesz) {
 388                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 389                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 390                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 391                         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)
 392                                 goto error;
 393                 }
 394         }
 395         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 396                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 397                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
 398                                 goto error;
 399                         break;
 400                 }
 401         if (!runtime) reclaim_gaps(base, ph0, eh->e_phentsize, eh->e_phnum);
 402         dso->map = map;
 403         dso->map_len = map_len;
 404         dso->base = base;
 405         dso->dynv = (void *)(base+dyn);
 406         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 407         return map;
 408 error:
 409         munmap(map, map_len);
 410         return 0;
 411 }
 412
 413 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 414 {
 415         size_t l;
 416         int fd;
 417         for (;;) {
 418                 s += strspn(s, ":\n");
 419                 l = strcspn(s, ":\n");
 420                 if (l-1 >= INT_MAX) return -1;
 421                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
 422                         continue;
 423                 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 424                 s += l;
 425         }
 426 }
 427
 428 static void decode_dyn(struct dso *p)
 429 {
 430         size_t dyn[DYN_CNT] = {0};
 431         decode_vec(p->dynv, dyn, DYN_CNT);
 432         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 433         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 434         if (dyn[0]&(1<<DT_HASH))
 435                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 436         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 437                 p->ghashtab = (void *)(p->base + *dyn);
 438 }
 439
 440 static struct dso *load_library(const char *name)
 441 {
 442         char buf[2*NAME_MAX+2];
 443         const char *pathname;
 444         unsigned char *map;
 445         struct dso *p, temp_dso = {0};
 446         int fd;
 447         struct stat st;
 448         size_t alloc_size;
 449         int n_th = 0;
 450
 451         /* Catch and block attempts to reload the implementation itself */
 452         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 453                 static const char *rp, reserved[] =
 454                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 455                 char *z = strchr(name, '.');
 456                 if (z) {
 457                         size_t l = z-name;
 458                         for (rp=reserved; *rp && memcmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 459                         if (*rp) {
 460                                 if (!ldso->prev) {
 461                                         tail->next = ldso;
 462                                         ldso->prev = tail;
 463                                         tail = ldso->next ? ldso->next : ldso;
 464                                 }
 465                                 return ldso;
 466                         }
 467                 }
 468         }
 469         if (strchr(name, '/')) {
 470                 pathname = name;
 471                 fd = open(name, O_RDONLY|O_CLOEXEC);
 472         } else {
 473                 /* Search for the name to see if it's already loaded */
 474                 for (p=head->next; p; p=p->next) {
 475                         if (p->shortname && !strcmp(p->shortname, name)) {
 476                                 p->refcnt++;
 477                                 return p;
 478                         }
 479                 }
 480                 if (strlen(name) > NAME_MAX) return 0;
 481                 fd = -1;
 482                 if (r_path) fd = path_open(name, r_path, buf, sizeof buf);
 483                 if (fd < 0 && env_path) fd = path_open(name, env_path, buf, sizeof buf);
 484                 if (fd < 0) {
 485                         if (!sys_path) {
 486                                 char *prefix = 0;
 487                                 size_t prefix_len;
 488                                 if (ldso->name[0]=='/') {
 489                                         char *s, *t, *z;
 490                                         for (s=t=z=ldso->name; *s; s++)
 491                                                 if (*s=='/') z=t, t=s;
 492                                         prefix_len = z-ldso->name;
 493                                         if (prefix_len < PATH_MAX)
 494                                                 prefix = ldso->name;
 495                                 }
 496                                 if (!prefix) {
 497                                         prefix = "";
 498                                         prefix_len = 0;
 499                                 }
 500                                 char etc_ldso_path[prefix_len + 1
 501                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
 502                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
 503                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
 504                                         (int)prefix_len, prefix);
 505                                 FILE *f = fopen(etc_ldso_path, "rbe");
 506                                 if (f) {
 507                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
 508                                                 free(sys_path);
 509                                                 sys_path = "";
 510                                         }
 511                                         fclose(f);
 512                                 }
 513                         }
 514                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
 515                         fd = path_open(name, sys_path, buf, sizeof buf);
 516                 }
 517                 pathname = buf;
 518         }
 519         if (fd < 0) return 0;
 520         if (fstat(fd, &st) < 0) {
 521                 close(fd);
 522                 return 0;
 523         }
 524         for (p=head->next; p; p=p->next) {
 525                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 526                         /* If this library was previously loaded with a
 527                          * pathname but a search found the same inode,
 528                          * setup its shortname so it can be found by name. */
 529                         if (!p->shortname && pathname != name)
 530                                 p->shortname = strrchr(p->name, '/')+1;
 531                         close(fd);
 532                         p->refcnt++;
 533                         return p;
 534                 }
 535         }
 536         map = noload ? 0 : map_library(fd, &temp_dso);
 537         close(fd);
 538         if (!map) return 0;
 539
 540         /* Allocate storage for the new DSO. When there is TLS, this
 541          * storage must include a reservation for all pre-existing
 542          * threads to obtain copies of both the new TLS, and an
 543          * extended DTV capable of storing an additional slot for
 544          * the newly-loaded DSO. */
 545         alloc_size = sizeof *p + strlen(pathname) + 1;
 546         if (runtime && temp_dso.tls_image) {
 547                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 548                         + sizeof(void *) * (tls_cnt+3);
 549                 n_th = libc.threads_minus_1 + 1;
 550                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 551                 else alloc_size += n_th * per_th;
 552         }
 553         p = calloc(1, alloc_size);
 554         if (!p) {
 555                 munmap(map, temp_dso.map_len);
 556                 return 0;
 557         }
 558         memcpy(p, &temp_dso, sizeof temp_dso);
 559         decode_dyn(p);
 560         p->dev = st.st_dev;
 561         p->ino = st.st_ino;
 562         p->refcnt = 1;
 563         p->name = p->buf;
 564         strcpy(p->name, pathname);
 565         /* Add a shortname only if name arg was not an explicit pathname. */
 566         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 567         if (p->tls_image) {
 568                 if (runtime && !__pthread_self_init()) {
 569                         munmap(map, p->map_len);
 570                         free(p);
 571                         return 0;
 572                 }
 573                 p->tls_id = ++tls_cnt;
 574                 tls_align = MAXP2(tls_align, p->tls_align);
 575 #ifdef TLS_ABOVE_TP
 576                 p->tls_offset = tls_offset + ( (tls_align-1) &
 577                         -(tls_offset + (uintptr_t)p->tls_image) );
 578                 tls_offset += p->tls_size;
 579 #else
 580                 tls_offset += p->tls_size + p->tls_align - 1;
 581                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 582                         & (p->tls_align-1);
 583                 p->tls_offset = tls_offset;
 584 #endif
 585                 p->new_dtv = (void *)(-sizeof(size_t) &
 586                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 587                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 588         }
 589
 590         tail->next = p;
 591         p->prev = tail;
 592         tail = p;
 593
 594         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 595
 596         return p;
 597 }
 598
 599 static void load_deps(struct dso *p)
 600 {
 601         size_t i, ndeps=0;
 602         struct dso ***deps = &p->deps, **tmp, *dep;
 603         for (; p; p=p->next) {
 604                 for (i=0; p->dynv[i]; i+=2) {
 605                         if (p->dynv[i] != DT_RPATH) continue;
 606                         r_path = (void *)(p->strings + p->dynv[i+1]);
 607                 }
 608                 for (i=0; p->dynv[i]; i+=2) {
 609                         if (p->dynv[i] != DT_NEEDED) continue;
 610                         dep = load_library(p->strings + p->dynv[i+1]);
 611                         if (!dep) {
 612                                 snprintf(errbuf, sizeof errbuf,
 613                                         "Error loading shared library %s: %m (needed by %s)",
 614                                         p->strings + p->dynv[i+1], p->name);
 615                                 if (runtime) longjmp(rtld_fail, 1);
 616                                 dprintf(2, "%s\n", errbuf);
 617                                 ldso_fail = 1;
 618                                 continue;
 619                         }
 620                         if (runtime) {
 621                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 622                                 if (!tmp) longjmp(rtld_fail, 1);
 623                                 tmp[ndeps++] = dep;
 624                                 tmp[ndeps] = 0;
 625                                 *deps = tmp;
 626                         }
 627                 }
 628                 r_path = 0;
 629         }
 630 }
 631
 632 static void load_preload(char *s)
 633 {
 634         int tmp;
 635         char *z;
 636         for (z=s; *z; s=z) {
 637                 for (   ; *s && isspace(*s); s++);
 638                 for (z=s; *z && !isspace(*z); z++);
 639                 tmp = *z;
 640                 *z = 0;
 641                 load_library(s);
 642                 *z = tmp;
 643         }
 644 }
 645
 646 static void make_global(struct dso *p)
 647 {
 648         for (; p; p=p->next) p->global = 1;
 649 }
 650
 651 static void reloc_all(struct dso *p)
 652 {
 653         size_t dyn[DYN_CNT] = {0};
 654         for (; p; p=p->next) {
 655                 if (p->relocated) continue;
 656                 decode_vec(p->dynv, dyn, DYN_CNT);
 657 #ifdef NEED_ARCH_RELOCS
 658                 do_arch_relocs(p, head);
 659 #endif
 660                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 661                         2+(dyn[DT_PLTREL]==DT_RELA));
 662                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 663                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 664                 p->relocated = 1;
 665         }
 666 }
 667
 668 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
 669 {
 670         for (; cnt--; ph = (void *)((char *)ph + stride))
 671                 if (ph->p_type == PT_DYNAMIC)
 672                         return ph->p_vaddr;
 673         return 0;
 674 }
 675
 676 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
 677 {
 678         size_t min_addr = -1, max_addr = 0;
 679         for (; cnt--; ph = (void *)((char *)ph + stride)) {
 680                 if (ph->p_type != PT_LOAD) continue;
 681                 if (ph->p_vaddr < min_addr)
 682                         min_addr = ph->p_vaddr;
 683                 if (ph->p_vaddr+ph->p_memsz > max_addr)
 684                         max_addr = ph->p_vaddr+ph->p_memsz;
 685         }
 686         min_addr &= -PAGE_SIZE;
 687         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
 688         p->map = p->base + min_addr;
 689         p->map_len = max_addr - min_addr;
 690 }
 691
 692 static void do_fini()
 693 {
 694         struct dso *p;
 695         size_t dyn[DYN_CNT] = {0};
 696         for (p=fini_head; p; p=p->fini_next) {
 697                 if (!p->constructed) continue;
 698                 decode_vec(p->dynv, dyn, DYN_CNT);
 699                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
 700                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
 701                         size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
 702                         while (n--) ((void (*)(void))*--fn)();
 703                 }
 704                 if (dyn[0] & (1<<DT_FINI))
 705                         ((void (*)(void))(p->base + dyn[DT_FINI]))();
 706         }
 707 }
 708
 709 static void do_init_fini(struct dso *p)
 710 {
 711         size_t dyn[DYN_CNT] = {0};
 712         int need_locking = libc.threads_minus_1;
 713         /* Allow recursive calls that arise when a library calls
 714          * dlopen from one of its constructors, but block any
 715          * other threads until all ctors have finished. */
 716         if (need_locking) pthread_mutex_lock(&init_fini_lock);
 717         for (; p; p=p->prev) {
 718                 if (p->constructed) continue;
 719                 p->constructed = 1;
 720                 decode_vec(p->dynv, dyn, DYN_CNT);
 721                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
 722                         p->fini_next = fini_head;
 723                         fini_head = p;
 724                 }
 725                 if (dyn[0] & (1<<DT_INIT))
 726                         ((void (*)(void))(p->base + dyn[DT_INIT]))();
 727                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
 728                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
 729                         size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
 730                         while (n--) ((void (*)(void))*fn++)();
 731                 }
 732                 if (!need_locking && libc.threads_minus_1) {
 733                         need_locking = 1;
 734                         pthread_mutex_lock(&init_fini_lock);
 735                 }
 736         }
 737         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
 738 }
 739
 740 void _dl_debug_state(void)
 741 {
 742 }
 743
 744 void *__copy_tls(unsigned char *mem)
 745 {
 746         pthread_t td;
 747         struct dso *p;
 748
 749         if (!tls_cnt) return mem;
 750
 751         void **dtv = (void *)mem;
 752         dtv[0] = (void *)tls_cnt;
 753
 754 #ifdef TLS_ABOVE_TP
 755         mem += sizeof(void *) * (tls_cnt+1);
 756         mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
 757         td = (pthread_t)mem;
 758         mem += sizeof(struct pthread);
 759
 760         for (p=head; p; p=p->next) {
 761                 if (!p->tls_id) continue;
 762                 dtv[p->tls_id] = mem + p->tls_offset;
 763                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 764         }
 765 #else
 766         mem += libc.tls_size - sizeof(struct pthread);
 767         mem -= (uintptr_t)mem & (tls_align-1);
 768         td = (pthread_t)mem;
 769
 770         for (p=head; p; p=p->next) {
 771                 if (!p->tls_id) continue;
 772                 dtv[p->tls_id] = mem - p->tls_offset;
 773                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 774         }
 775 #endif
 776         td->dtv = dtv;
 777         return td;
 778 }
 779
 780 void *__tls_get_addr(size_t *v)
 781 {
 782         pthread_t self = __pthread_self();
 783         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
 784                 return (char *)self->dtv[v[0]]+v[1];
 785
 786         /* Block signals to make accessing new TLS async-signal-safe */
 787         sigset_t set;
 788         pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
 789         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
 790                 pthread_sigmask(SIG_SETMASK, &set, 0);
 791                 return (char *)self->dtv[v[0]]+v[1];
 792         }
 793
 794         /* This is safe without any locks held because, if the caller
 795          * is able to request the Nth entry of the DTV, the DSO list
 796          * must be valid at least that far out and it was synchronized
 797          * at program startup or by an already-completed call to dlopen. */
 798         struct dso *p;
 799         for (p=head; p->tls_id != v[0]; p=p->next);
 800
 801         /* Get new DTV space from new DSO if needed */
 802         if (v[0] > (size_t)self->dtv[0]) {
 803                 void **newdtv = p->new_dtv +
 804                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
 805                 memcpy(newdtv, self->dtv,
 806                         ((size_t)self->dtv[0]+1) * sizeof(void *));
 807                 newdtv[0] = (void *)v[0];
 808                 self->dtv = newdtv;
 809         }
 810
 811         /* Get new TLS memory from new DSO */
 812         unsigned char *mem = p->new_tls +
 813                 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
 814         mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
 815         self->dtv[v[0]] = mem;
 816         memcpy(mem, p->tls_image, p->tls_len);
 817         pthread_sigmask(SIG_SETMASK, &set, 0);
 818         return mem + v[1];
 819 }
 820
 821 static void update_tls_size()
 822 {
 823         libc.tls_size = ALIGN(
 824                 (1+tls_cnt) * sizeof(void *) +
 825                 tls_offset +
 826                 sizeof(struct pthread) +
 827                 tls_align * 2,
 828         tls_align);
 829 }
 830
 831 void *__dynlink(int argc, char **argv)
 832 {
 833         size_t aux[AUX_CNT] = {0};
 834         size_t i;
 835         Phdr *phdr;
 836         Ehdr *ehdr;
 837         static struct dso builtin_dsos[3];
 838         struct dso *const app = builtin_dsos+0;
 839         struct dso *const lib = builtin_dsos+1;
 840         struct dso *const vdso = builtin_dsos+2;
 841         char *env_preload=0;
 842         size_t vdso_base;
 843         size_t *auxv;
 844
 845         /* Find aux vector just past environ[] */
 846         for (i=argc+1; argv[i]; i++)
 847                 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
 848                         env_path = argv[i]+16;
 849                 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
 850                         env_preload = argv[i]+11;
 851         auxv = (void *)(argv+i+1);
 852
 853         decode_vec(auxv, aux, AUX_CNT);
 854
 855         /* Only trust user/env if kernel says we're not suid/sgid */
 856         if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
 857           || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
 858                 env_path = 0;
 859                 env_preload = 0;
 860         }
 861
 862         /* If the dynamic linker was invoked as a program itself, AT_BASE
 863          * will not be set. In that case, we assume the base address is
 864          * the start of the page containing the PHDRs; I don't know any
 865          * better approach... */
 866         if (!aux[AT_BASE]) {
 867                 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
 868                 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
 869         }
 870
 871         /* The dynamic linker load address is passed by the kernel
 872          * in the AUX vector, so this is easy. */
 873         lib->base = (void *)aux[AT_BASE];
 874         lib->name = lib->shortname = "libc.so";
 875         lib->global = 1;
 876         ehdr = (void *)lib->base;
 877         lib->phnum = ehdr->e_phnum;
 878         lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
 879         find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
 880         lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
 881                     ehdr->e_phnum, ehdr->e_phentsize));
 882         decode_dyn(lib);
 883
 884         if (aux[AT_PHDR]) {
 885                 size_t interp_off = 0;
 886                 size_t tls_image = 0;
 887                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
 888                 app->phdr = phdr = (void *)aux[AT_PHDR];
 889                 app->phnum = aux[AT_PHNUM];
 890                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
 891                         if (phdr->p_type == PT_PHDR)
 892                                 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
 893                         else if (phdr->p_type == PT_INTERP)
 894                                 interp_off = (size_t)phdr->p_vaddr;
 895                         else if (phdr->p_type == PT_TLS) {
 896                                 tls_image = phdr->p_vaddr;
 897                                 app->tls_len = phdr->p_filesz;
 898                                 app->tls_size = phdr->p_memsz;
 899                                 app->tls_align = phdr->p_align;
 900                         }
 901                 }
 902                 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
 903                 if (interp_off) lib->name = (char *)app->base + interp_off;
 904                 app->name = argv[0];
 905                 app->dynv = (void *)(app->base + find_dyn(
 906                         (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
 907                 find_map_range((void *)aux[AT_PHDR],
 908                         aux[AT_PHNUM], aux[AT_PHENT], app);
 909         } else {
 910                 int fd;
 911                 char *ldname = argv[0];
 912                 size_t l = strlen(ldname);
 913                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
 914                 *argv++ = (void *)-1;
 915                 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
 916                 if (!argv[0]) {
 917                         dprintf(2, "musl libc/dynamic program loader\n");
 918                         dprintf(2, "usage: %s pathname%s\n", ldname,
 919                                 ldd_mode ? "" : " [args]");
 920                         _exit(1);
 921                 }
 922                 fd = open(argv[0], O_RDONLY);
 923                 if (fd < 0) {
 924                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
 925                         _exit(1);
 926                 }
 927                 runtime = 1;
 928                 ehdr = (void *)map_library(fd, app);
 929                 if (!ehdr) {
 930                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
 931                         _exit(1);
 932                 }
 933                 runtime = 0;
 934                 close(fd);
 935                 lib->name = ldname;
 936                 app->name = argv[0];
 937                 app->phnum = ehdr->e_phnum;
 938                 app->phdr = (void *)(app->base + ehdr->e_phoff);
 939                 aux[AT_ENTRY] = ehdr->e_entry;
 940         }
 941         if (app->tls_size) {
 942                 app->tls_id = tls_cnt = 1;
 943 #ifdef TLS_ABOVE_TP
 944                 app->tls_offset = 0;
 945                 tls_offset = app->tls_size
 946                         + ( -((uintptr_t)app->tls_image + app->tls_size)
 947                         & (app->tls_align-1) );
 948 #else
 949                 tls_offset = app->tls_offset = app->tls_size
 950                         + ( -((uintptr_t)app->tls_image + app->tls_size)
 951                         & (app->tls_align-1) );
 952 #endif
 953                 tls_align = MAXP2(tls_align, app->tls_align);
 954         }
 955         app->global = 1;
 956         app->constructed = 1;
 957         decode_dyn(app);
 958
 959         /* Attach to vdso, if provided by the kernel */
 960         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
 961                 ehdr = (void *)vdso_base;
 962                 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
 963                 vdso->phnum = ehdr->e_phnum;
 964                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
 965                         if (phdr->p_type == PT_DYNAMIC)
 966                                 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
 967                         if (phdr->p_type == PT_LOAD)
 968                                 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
 969                 }
 970                 vdso->name = "";
 971                 vdso->shortname = "linux-gate.so.1";
 972                 vdso->global = 1;
 973                 decode_dyn(vdso);
 974                 vdso->prev = lib;
 975                 lib->next = vdso;
 976         }
 977
 978         /* Initial dso chain consists only of the app. We temporarily
 979          * append the dynamic linker/libc so we can relocate it, then
 980          * restore the initial chain in preparation for loading third
 981          * party libraries (preload/needed). */
 982         head = tail = app;
 983         ldso = lib;
 984         app->next = lib;
 985         reloc_all(lib);
 986         app->next = 0;
 987
 988         /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
 989
 990         /* Donate unused parts of app and library mapping to malloc */
 991         reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
 992         ehdr = (void *)lib->base;
 993         reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
 994                 ehdr->e_phentsize, ehdr->e_phnum);
 995
 996         /* Load preload/needed libraries, add their symbols to the global
 997          * namespace, and perform all remaining relocations. The main
 998          * program must be relocated LAST since it may contain copy
 999          * relocations which depend on libraries' relocations. */
1000         if (env_preload) load_preload(env_preload);
1001         load_deps(app);
1002         make_global(app);
1003
1004         reloc_all(app->next);
1005         reloc_all(app);
1006
1007         update_tls_size();
1008         if (tls_cnt) {
1009                 void *mem = mmap(0, libc.tls_size, PROT_READ|PROT_WRITE,
1010                         MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
1011                 if (mem==MAP_FAILED ||
1012                     !__install_initial_tls(__copy_tls(mem))) {
1013                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1014                                 argv[0], libc.tls_size);
1015                         _exit(127);
1016                 }
1017         }
1018
1019         if (ldso_fail) _exit(127);
1020         if (ldd_mode) _exit(0);
1021
1022         /* Switch to runtime mode: any further failures in the dynamic
1023          * linker are a reportable failure rather than a fatal startup
1024          * error. If the dynamic loader (dlopen) will not be used, free
1025          * all memory used by the dynamic linker. */
1026         runtime = 1;
1027
1028 #ifndef DYNAMIC_IS_RO
1029         for (i=0; app->dynv[i]; i+=2)
1030                 if (app->dynv[i]==DT_DEBUG)
1031                         app->dynv[i+1] = (size_t)&debug;
1032 #endif
1033         debug.ver = 1;
1034         debug.bp = _dl_debug_state;
1035         debug.head = head;
1036         debug.base = lib->base;
1037         debug.state = 0;
1038         _dl_debug_state();
1039
1040         if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
1041
1042         errno = 0;
1043         return (void *)aux[AT_ENTRY];
1044 }
1045
1046 void __init_ldso_ctors(void)
1047 {
1048         atexit(do_fini);
1049         do_init_fini(tail);
1050 }
1051
1052 void *dlopen(const char *file, int mode)
1053 {
1054         struct dso *volatile p, *orig_tail, *next;
1055         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1056         size_t i;
1057         int cs;
1058
1059         if (!file) return head;
1060
1061         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1062         pthread_rwlock_wrlock(&lock);
1063         __inhibit_ptc();
1064
1065         p = 0;
1066         orig_tls_cnt = tls_cnt;
1067         orig_tls_offset = tls_offset;
1068         orig_tls_align = tls_align;
1069         orig_tail = tail;
1070         noload = mode & RTLD_NOLOAD;
1071
1072         if (setjmp(rtld_fail)) {
1073                 /* Clean up anything new that was (partially) loaded */
1074                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1075                         if (p->deps[i]->global < 0)
1076                                 p->deps[i]->global = 0;
1077                 for (p=orig_tail->next; p; p=next) {
1078                         next = p->next;
1079                         munmap(p->map, p->map_len);
1080                         free(p->deps);
1081                         free(p);
1082                 }
1083                 tls_cnt = orig_tls_cnt;
1084                 tls_offset = orig_tls_offset;
1085                 tls_align = orig_tls_align;
1086                 tail = orig_tail;
1087                 tail->next = 0;
1088                 p = 0;
1089                 errflag = 1;
1090                 goto end;
1091         } else p = load_library(file);
1092
1093         if (!p) {
1094                 snprintf(errbuf, sizeof errbuf, noload ?
1095                         "Library %s is not already loaded" :
1096                         "Error loading shared library %s: %m",
1097                         file);
1098                 errflag = 1;
1099                 goto end;
1100         }
1101
1102         /* First load handling */
1103         if (!p->deps) {
1104                 load_deps(p);
1105                 if (p->deps) for (i=0; p->deps[i]; i++)
1106                         if (!p->deps[i]->global)
1107                                 p->deps[i]->global = -1;
1108                 if (!p->global) p->global = -1;
1109                 reloc_all(p);
1110                 if (p->deps) for (i=0; p->deps[i]; i++)
1111                         if (p->deps[i]->global < 0)
1112                                 p->deps[i]->global = 0;
1113                 if (p->global < 0) p->global = 0;
1114         }
1115
1116         if (mode & RTLD_GLOBAL) {
1117                 if (p->deps) for (i=0; p->deps[i]; i++)
1118                         p->deps[i]->global = 1;
1119                 p->global = 1;
1120         }
1121
1122         update_tls_size();
1123
1124         if (ssp_used) __init_ssp(libc.auxv);
1125
1126         _dl_debug_state();
1127         orig_tail = tail;
1128 end:
1129         __release_ptc();
1130         if (p) gencnt++;
1131         pthread_rwlock_unlock(&lock);
1132         if (p) do_init_fini(orig_tail);
1133         pthread_setcancelstate(cs, 0);
1134         return p;
1135 }
1136
1137 static int invalid_dso_handle(void *h)
1138 {
1139         struct dso *p;
1140         for (p=head; p; p=p->next) if (h==p) return 0;
1141         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1142         errflag = 1;
1143         return 1;
1144 }
1145
1146 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1147 {
1148         size_t i;
1149         uint32_t h = 0, gh = 0;
1150         Sym *sym;
1151         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1152                 if (p == RTLD_DEFAULT) {
1153                         p = head;
1154                 } else if (p == RTLD_NEXT) {
1155                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1156                         if (!p) p=head;
1157                         p = p->next;
1158                 }
1159                 struct symdef def = find_sym(p, s, 0);
1160                 if (!def.sym) goto failed;
1161                 if ((def.sym->st_info&0xf) == STT_TLS)
1162                         return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1163                 return def.dso->base + def.sym->st_value;
1164         }
1165         if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1166                 return 0;
1167         if (p->ghashtab) {
1168                 gh = gnu_hash(s);
1169                 sym = gnu_lookup(s, gh, p);
1170         } else {
1171                 h = sysv_hash(s);
1172                 sym = sysv_lookup(s, h, p);
1173         }
1174         if (sym && (sym->st_info&0xf) == STT_TLS)
1175                 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1176         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1177                 return p->base + sym->st_value;
1178         if (p->deps) for (i=0; p->deps[i]; i++) {
1179                 if (p->deps[i]->ghashtab) {
1180                         if (!gh) gh = gnu_hash(s);
1181                         sym = gnu_lookup(s, gh, p->deps[i]);
1182                 } else {
1183                         if (!h) h = sysv_hash(s);
1184                         sym = sysv_lookup(s, h, p->deps[i]);
1185                 }
1186                 if (sym && (sym->st_info&0xf) == STT_TLS)
1187                         return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1188                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1189                         return p->deps[i]->base + sym->st_value;
1190         }
1191 failed:
1192         errflag = 1;
1193         snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1194         return 0;
1195 }
1196
1197 int __dladdr(void *addr, Dl_info *info)
1198 {
1199         struct dso *p;
1200         Sym *sym;
1201         uint32_t nsym;
1202         char *strings;
1203         size_t i;
1204         void *best = 0;
1205         char *bestname;
1206
1207         pthread_rwlock_rdlock(&lock);
1208         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1209         pthread_rwlock_unlock(&lock);
1210
1211         if (!p) return 0;
1212
1213         sym = p->syms;
1214         strings = p->strings;
1215         if (p->hashtab) {
1216                 nsym = p->hashtab[1];
1217         } else {
1218                 uint32_t *buckets;
1219                 uint32_t *hashval;
1220                 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1221                 sym += p->ghashtab[1];
1222                 for (i = 0; i < p->ghashtab[0]; i++) {
1223                         if (buckets[i] > nsym)
1224                                 nsym = buckets[i];
1225                 }
1226                 if (nsym) {
1227                         nsym -= p->ghashtab[1];
1228                         hashval = buckets + p->ghashtab[0] + nsym;
1229                         do nsym++;
1230                         while (!(*hashval++ & 1));
1231                 }
1232         }
1233
1234         for (; nsym; nsym--, sym++) {
1235                 if (sym->st_value
1236                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1237                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1238                         void *symaddr = p->base + sym->st_value;
1239                         if (symaddr > addr || symaddr < best)
1240                                 continue;
1241                         best = symaddr;
1242                         bestname = strings + sym->st_name;
1243                         if (addr == symaddr)
1244                                 break;
1245                 }
1246         }
1247
1248         if (!best) return 0;
1249
1250         info->dli_fname = p->name;
1251         info->dli_fbase = p->base;
1252         info->dli_sname = bestname;
1253         info->dli_saddr = best;
1254
1255         return 1;
1256 }
1257
1258 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1259 {
1260         void *res;
1261         pthread_rwlock_rdlock(&lock);
1262         res = do_dlsym(p, s, ra);
1263         pthread_rwlock_unlock(&lock);
1264         return res;
1265 }
1266
1267 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1268 {
1269         struct dso *current;
1270         struct dl_phdr_info info;
1271         int ret = 0;
1272         for(current = head; current;) {
1273                 info.dlpi_addr      = (uintptr_t)current->base;
1274                 info.dlpi_name      = current->name;
1275                 info.dlpi_phdr      = current->phdr;
1276                 info.dlpi_phnum     = current->phnum;
1277                 info.dlpi_adds      = gencnt;
1278                 info.dlpi_subs      = 0;
1279                 info.dlpi_tls_modid = current->tls_id;
1280                 info.dlpi_tls_data  = current->tls_image;
1281
1282                 ret = (callback)(&info, sizeof (info), data);
1283
1284                 if (ret != 0) break;
1285
1286                 pthread_rwlock_rdlock(&lock);
1287                 current = current->next;
1288                 pthread_rwlock_unlock(&lock);
1289         }
1290         return ret;
1291 }
1292 #else
1293 static int invalid_dso_handle(void *h)
1294 {
1295         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1296         errflag = 1;
1297         return 1;
1298 }
1299 void *dlopen(const char *file, int mode)
1300 {
1301         return 0;
1302 }
1303 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1304 {
1305         return 0;
1306 }
1307 int __dladdr (void *addr, Dl_info *info)
1308 {
1309         return 0;
1310 }
1311 #endif
1312
1313 int __dlinfo(void *dso, int req, void *res)
1314 {
1315         if (invalid_dso_handle(dso)) return -1;
1316         if (req != RTLD_DI_LINKMAP) {
1317                 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1318                 errflag = 1;
1319                 return -1;
1320         }
1321         *(struct link_map **)res = dso;
1322         return 0;
1323 }
1324
1325 char *dlerror()
1326 {
1327         if (!errflag) return 0;
1328         errflag = 0;
1329         return errbuf;
1330 }
1331
1332 int dlclose(void *p)
1333 {
1334         return invalid_dso_handle(p);
1335 }