ldso/dynlink.c

   1 #define _GNU_SOURCE
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <stdarg.h>
   5 #include <stddef.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8 #include <stdint.h>
   9 #include <elf.h>
  10 #include <sys/mman.h>
  11 #include <limits.h>
  12 #include <fcntl.h>
  13 #include <sys/stat.h>
  14 #include <errno.h>
  15 #include <link.h>
  16 #include <setjmp.h>
  17 #include <pthread.h>
  18 #include <ctype.h>
  19 #include <dlfcn.h>
  20 #include "pthread_impl.h"
  21 #include "libc.h"
  22 #include "dynlink.h"
  23
  24 static void error(const char *, ...);
  25
  26 #define MAXP2(a,b) (-(-(a)&-(b)))
  27 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  28
  29 struct debug {
  30         int ver;
  31         void *head;
  32         void (*bp)(void);
  33         int state;
  34         void *base;
  35 };
  36
  37 struct td_index {
  38         size_t args[2];
  39         struct td_index *next;
  40 };
  41
  42 struct dso {
  43 #if DL_FDPIC
  44         struct fdpic_loadmap *loadmap;
  45 #else
  46         unsigned char *base;
  47 #endif
  48         char *name;
  49         size_t *dynv;
  50         struct dso *next, *prev;
  51
  52         Phdr *phdr;
  53         int phnum;
  54         size_t phentsize;
  55         int refcnt;
  56         Sym *syms;
  57         Elf_Symndx *hashtab;
  58         uint32_t *ghashtab;
  59         int16_t *versym;
  60         char *strings;
  61         struct dso *syms_next, *lazy_next;
  62         size_t *lazy, lazy_cnt;
  63         unsigned char *map;
  64         size_t map_len;
  65         dev_t dev;
  66         ino_t ino;
  67         char relocated;
  68         char constructed;
  69         char kernel_mapped;
  70         struct dso **deps, *needed_by;
  71         char *rpath_orig, *rpath;
  72         struct tls_module tls;
  73         size_t tls_id;
  74         size_t relro_start, relro_end;
  75         void **new_dtv;
  76         unsigned char *new_tls;
  77         volatile int new_dtv_idx, new_tls_idx;
  78         struct td_index *td_index;
  79         struct dso *fini_next;
  80         char *shortname;
  81 #if DL_FDPIC
  82         unsigned char *base;
  83 #else
  84         struct fdpic_loadmap *loadmap;
  85 #endif
  86         struct funcdesc {
  87                 void *addr;
  88                 size_t *got;
  89         } *funcdescs;
  90         size_t *got;
  91         char buf[];
  92 };
  93
  94 struct symdef {
  95         Sym *sym;
  96         struct dso *dso;
  97 };
  98
  99 int __init_tp(void *);
 100 void __init_libc(char **, char *);
 101 void *__copy_tls(unsigned char *);
 102
 103 __attribute__((__visibility__("hidden")))
 104 const char *__libc_get_version(void);
 105
 106 static struct builtin_tls {
 107         char c;
 108         struct pthread pt;
 109         void *space[16];
 110 } builtin_tls[1];
 111 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
 112
 113 #define ADDEND_LIMIT 4096
 114 static size_t *saved_addends, *apply_addends_to;
 115
 116 static struct dso ldso;
 117 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
 118 static char *env_path, *sys_path;
 119 static unsigned long long gencnt;
 120 static int runtime;
 121 static int ldd_mode;
 122 static int ldso_fail;
 123 static int noload;
 124 static jmp_buf *rtld_fail;
 125 static pthread_rwlock_t lock;
 126 static struct debug debug;
 127 static struct tls_module *tls_tail;
 128 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
 129 static size_t static_tls_cnt;
 130 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 131 static struct fdpic_loadmap *app_loadmap;
 132 static struct fdpic_dummy_loadmap app_dummy_loadmap;
 133
 134 struct debug *_dl_debug_addr = &debug;
 135
 136 __attribute__((__visibility__("hidden")))
 137 void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
 138
 139 __attribute__((__visibility__("hidden")))
 140 extern void (*const __init_array_end)(void), (*const __fini_array_end)(void);
 141
 142 weak_alias(__init_array_start, __init_array_end);
 143 weak_alias(__fini_array_start, __fini_array_end);
 144
 145 static int dl_strcmp(const char *l, const char *r)
 146 {
 147         for (; *l==*r && *l; l++, r++);
 148         return *(unsigned char *)l - *(unsigned char *)r;
 149 }
 150 #define strcmp(l,r) dl_strcmp(l,r)
 151
 152 /* Compute load address for a virtual address in a given dso. */
 153 #if DL_FDPIC
 154 static void *laddr(const struct dso *p, size_t v)
 155 {
 156         size_t j=0;
 157         if (!p->loadmap) return p->base + v;
 158         for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
 159         return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
 160 }
 161 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
 162         laddr(p, v), (p)->got })
 163 #else
 164 #define laddr(p, v) (void *)((p)->base + (v))
 165 #define fpaddr(p, v) ((void (*)())laddr(p, v))
 166 #endif
 167
 168 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 169 {
 170         size_t i;
 171         for (i=0; i<cnt; i++) a[i] = 0;
 172         for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
 173                 a[0] |= 1UL<<v[0];
 174                 a[v[0]] = v[1];
 175         }
 176 }
 177
 178 static int search_vec(size_t *v, size_t *r, size_t key)
 179 {
 180         for (; v[0]!=key; v+=2)
 181                 if (!v[0]) return 0;
 182         *r = v[1];
 183         return 1;
 184 }
 185
 186 static uint32_t sysv_hash(const char *s0)
 187 {
 188         const unsigned char *s = (void *)s0;
 189         uint_fast32_t h = 0;
 190         while (*s) {
 191                 h = 16*h + *s++;
 192                 h ^= h>>24 & 0xf0;
 193         }
 194         return h & 0xfffffff;
 195 }
 196
 197 static uint32_t gnu_hash(const char *s0)
 198 {
 199         const unsigned char *s = (void *)s0;
 200         uint_fast32_t h = 5381;
 201         for (; *s; s++)
 202                 h += h*32 + *s;
 203         return h;
 204 }
 205
 206 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 207 {
 208         size_t i;
 209         Sym *syms = dso->syms;
 210         Elf_Symndx *hashtab = dso->hashtab;
 211         char *strings = dso->strings;
 212         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 213                 if ((!dso->versym || dso->versym[i] >= 0)
 214                     && (!strcmp(s, strings+syms[i].st_name)))
 215                         return syms+i;
 216         }
 217         return 0;
 218 }
 219
 220 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
 221 {
 222         uint32_t nbuckets = hashtab[0];
 223         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 224         uint32_t i = buckets[h1 % nbuckets];
 225
 226         if (!i) return 0;
 227
 228         uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
 229
 230         for (h1 |= 1; ; i++) {
 231                 uint32_t h2 = *hashval++;
 232                 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
 233                     && !strcmp(s, dso->strings + dso->syms[i].st_name))
 234                         return dso->syms+i;
 235                 if (h2 & 1) break;
 236         }
 237
 238         return 0;
 239 }
 240
 241 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
 242 {
 243         const size_t *bloomwords = (const void *)(hashtab+4);
 244         size_t f = bloomwords[fofs & (hashtab[2]-1)];
 245         if (!(f & fmask)) return 0;
 246
 247         f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
 248         if (!(f & 1)) return 0;
 249
 250         return gnu_lookup(h1, hashtab, dso, s);
 251 }
 252
 253 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 254 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 255
 256 #ifndef ARCH_SYM_REJECT_UND
 257 #define ARCH_SYM_REJECT_UND(s) 0
 258 #endif
 259
 260 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 261 {
 262         uint32_t h = 0, gh, gho, *ght;
 263         size_t ghm = 0;
 264         struct symdef def = {0};
 265         for (; dso; dso=dso->syms_next) {
 266                 Sym *sym;
 267                 if ((ght = dso->ghashtab)) {
 268                         if (!ghm) {
 269                                 gh = gnu_hash(s);
 270                                 int maskbits = 8 * sizeof ghm;
 271                                 gho = gh / maskbits;
 272                                 ghm = 1ul << gh % maskbits;
 273                         }
 274                         sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
 275                 } else {
 276                         if (!h) h = sysv_hash(s);
 277                         sym = sysv_lookup(s, h, dso);
 278                 }
 279                 if (!sym) continue;
 280                 if (!sym->st_shndx)
 281                         if (need_def || (sym->st_info&0xf) == STT_TLS
 282                             || ARCH_SYM_REJECT_UND(sym))
 283                                 continue;
 284                 if (!sym->st_value)
 285                         if ((sym->st_info&0xf) != STT_TLS)
 286                                 continue;
 287                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 288                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 289                 def.sym = sym;
 290                 def.dso = dso;
 291                 break;
 292         }
 293         return def;
 294 }
 295
 296 __attribute__((__visibility__("hidden")))
 297 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
 298
 299 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 300 {
 301         unsigned char *base = dso->base;
 302         Sym *syms = dso->syms;
 303         char *strings = dso->strings;
 304         Sym *sym;
 305         const char *name;
 306         void *ctx;
 307         int type;
 308         int sym_index;
 309         struct symdef def;
 310         size_t *reloc_addr;
 311         size_t sym_val;
 312         size_t tls_val;
 313         size_t addend;
 314         int skip_relative = 0, reuse_addends = 0, save_slot = 0;
 315
 316         if (dso == &ldso) {
 317                 /* Only ldso's REL table needs addend saving/reuse. */
 318                 if (rel == apply_addends_to)
 319                         reuse_addends = 1;
 320                 skip_relative = 1;
 321         }
 322
 323         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 324                 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
 325                 type = R_TYPE(rel[1]);
 326                 if (type == REL_NONE) continue;
 327                 reloc_addr = laddr(dso, rel[0]);
 328
 329                 if (stride > 2) {
 330                         addend = rel[2];
 331                 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
 332                         addend = 0;
 333                 } else if (reuse_addends) {
 334                         /* Save original addend in stage 2 where the dso
 335                          * chain consists of just ldso; otherwise read back
 336                          * saved addend since the inline one was clobbered. */
 337                         if (head==&ldso)
 338                                 saved_addends[save_slot] = *reloc_addr;
 339                         addend = saved_addends[save_slot++];
 340                 } else {
 341                         addend = *reloc_addr;
 342                 }
 343
 344                 sym_index = R_SYM(rel[1]);
 345                 if (sym_index) {
 346                         sym = syms + sym_index;
 347                         name = strings + sym->st_name;
 348                         ctx = type==REL_COPY ? head->syms_next : head;
 349                         def = (sym->st_info&0xf) == STT_SECTION
 350                                 ? (struct symdef){ .dso = dso, .sym = sym }
 351                                 : find_sym(ctx, name, type==REL_PLT);
 352                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 353                             || sym->st_info>>4 != STB_WEAK)) {
 354                                 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
 355                                         dso->lazy[3*dso->lazy_cnt+0] = rel[0];
 356                                         dso->lazy[3*dso->lazy_cnt+1] = rel[1];
 357                                         dso->lazy[3*dso->lazy_cnt+2] = addend;
 358                                         dso->lazy_cnt++;
 359                                         continue;
 360                                 }
 361                                 error("Error relocating %s: %s: symbol not found",
 362                                         dso->name, name);
 363                                 if (runtime) longjmp(*rtld_fail, 1);
 364                                 continue;
 365                         }
 366                 } else {
 367                         sym = 0;
 368                         def.sym = 0;
 369                         def.dso = dso;
 370                 }
 371
 372                 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
 373                 tls_val = def.sym ? def.sym->st_value : 0;
 374
 375                 switch(type) {
 376                 case REL_NONE:
 377                         break;
 378                 case REL_OFFSET:
 379                         addend -= (size_t)reloc_addr;
 380                 case REL_SYMBOLIC:
 381                 case REL_GOT:
 382                 case REL_PLT:
 383                         *reloc_addr = sym_val + addend;
 384                         break;
 385                 case REL_RELATIVE:
 386                         *reloc_addr = (size_t)base + addend;
 387                         break;
 388                 case REL_SYM_OR_REL:
 389                         if (sym) *reloc_addr = sym_val + addend;
 390                         else *reloc_addr = (size_t)base + addend;
 391                         break;
 392                 case REL_COPY:
 393                         memcpy(reloc_addr, (void *)sym_val, sym->st_size);
 394                         break;
 395                 case REL_OFFSET32:
 396                         *(uint32_t *)reloc_addr = sym_val + addend
 397                                 - (size_t)reloc_addr;
 398                         break;
 399                 case REL_FUNCDESC:
 400                         *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
 401                                 + (def.sym - def.dso->syms)) : 0;
 402                         break;
 403                 case REL_FUNCDESC_VAL:
 404                         if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
 405                         else *reloc_addr = sym_val;
 406                         reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
 407                         break;
 408                 case REL_DTPMOD:
 409                         *reloc_addr = def.dso->tls_id;
 410                         break;
 411                 case REL_DTPOFF:
 412                         *reloc_addr = tls_val + addend - DTP_OFFSET;
 413                         break;
 414 #ifdef TLS_ABOVE_TP
 415                 case REL_TPOFF:
 416                         *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
 417                         break;
 418 #else
 419                 case REL_TPOFF:
 420                         *reloc_addr = tls_val - def.dso->tls.offset + addend;
 421                         break;
 422                 case REL_TPOFF_NEG:
 423                         *reloc_addr = def.dso->tls.offset - tls_val + addend;
 424                         break;
 425 #endif
 426                 case REL_TLSDESC:
 427                         if (stride<3) addend = reloc_addr[1];
 428                         if (runtime && def.dso->tls_id >= static_tls_cnt) {
 429                                 struct td_index *new = malloc(sizeof *new);
 430                                 if (!new) {
 431                                         error(
 432                                         "Error relocating %s: cannot allocate TLSDESC for %s",
 433                                         dso->name, sym ? name : "(local)" );
 434                                         longjmp(*rtld_fail, 1);
 435                                 }
 436                                 new->next = dso->td_index;
 437                                 dso->td_index = new;
 438                                 new->args[0] = def.dso->tls_id;
 439                                 new->args[1] = tls_val + addend;
 440                                 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
 441                                 reloc_addr[1] = (size_t)new;
 442                         } else {
 443                                 reloc_addr[0] = (size_t)__tlsdesc_static;
 444 #ifdef TLS_ABOVE_TP
 445                                 reloc_addr[1] = tls_val + def.dso->tls.offset
 446                                         + TPOFF_K + addend;
 447 #else
 448                                 reloc_addr[1] = tls_val - def.dso->tls.offset
 449                                         + addend;
 450 #endif
 451                         }
 452                         break;
 453                 default:
 454                         error("Error relocating %s: unsupported relocation type %d",
 455                                 dso->name, type);
 456                         if (runtime) longjmp(*rtld_fail, 1);
 457                         continue;
 458                 }
 459         }
 460 }
 461
 462 static void redo_lazy_relocs()
 463 {
 464         struct dso *p = lazy_head, *next;
 465         lazy_head = 0;
 466         for (; p; p=next) {
 467                 next = p->lazy_next;
 468                 size_t size = p->lazy_cnt*3*sizeof(size_t);
 469                 p->lazy_cnt = 0;
 470                 do_relocs(p, p->lazy, size, 3);
 471                 if (p->lazy_cnt) {
 472                         p->lazy_next = lazy_head;
 473                         lazy_head = p;
 474                 } else {
 475                         free(p->lazy);
 476                         p->lazy = 0;
 477                         p->lazy_next = 0;
 478                 }
 479         }
 480 }
 481
 482 /* A huge hack: to make up for the wastefulness of shared libraries
 483  * needing at least a page of dirty memory even if they have no global
 484  * data, we reclaim the gaps at the beginning and end of writable maps
 485  * and "donate" them to the heap by setting up minimal malloc
 486  * structures and then freeing them. */
 487
 488 static void reclaim(struct dso *dso, size_t start, size_t end)
 489 {
 490         size_t *a, *z;
 491         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 492         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 493         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 494         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 495         if (start>end || end-start < 4*sizeof(size_t)) return;
 496         a = laddr(dso, start);
 497         z = laddr(dso, end);
 498         a[-2] = 1;
 499         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 500         z[1] = 1;
 501         free(a);
 502 }
 503
 504 static void reclaim_gaps(struct dso *dso)
 505 {
 506         Phdr *ph = dso->phdr;
 507         size_t phcnt = dso->phnum;
 508
 509         if (DL_FDPIC) return; // FIXME
 510         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 511                 if (ph->p_type!=PT_LOAD) continue;
 512                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 513                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 514                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 515                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 516         }
 517 }
 518
 519 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
 520 {
 521         static int no_map_fixed;
 522         char *q;
 523         if (!no_map_fixed) {
 524                 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
 525                 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
 526                         return q;
 527                 no_map_fixed = 1;
 528         }
 529         /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
 530         if (flags & MAP_ANONYMOUS) {
 531                 memset(p, 0, n);
 532                 return p;
 533         }
 534         ssize_t r;
 535         if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
 536         for (q=p; n; q+=r, off+=r, n-=r) {
 537                 r = read(fd, q, n);
 538                 if (r < 0 && errno != EINTR) return MAP_FAILED;
 539                 if (!r) {
 540                         memset(q, 0, n);
 541                         break;
 542                 }
 543         }
 544         return p;
 545 }
 546
 547 static void unmap_library(struct dso *dso)
 548 {
 549         if (dso->loadmap) {
 550                 size_t i;
 551                 for (i=0; i<dso->loadmap->nsegs; i++) {
 552                         if (!dso->loadmap->segs[i].p_memsz)
 553                                 continue;
 554                         munmap((void *)dso->loadmap->segs[i].addr,
 555                                 dso->loadmap->segs[i].p_memsz);
 556                 }
 557                 free(dso->loadmap);
 558         } else if (dso->map && dso->map_len) {
 559                 munmap(dso->map, dso->map_len);
 560         }
 561 }
 562
 563 static void *map_library(int fd, struct dso *dso)
 564 {
 565         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 566         void *allocated_buf=0;
 567         size_t phsize;
 568         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 569         size_t this_min, this_max;
 570         size_t nsegs = 0;
 571         off_t off_start;
 572         Ehdr *eh;
 573         Phdr *ph, *ph0;
 574         unsigned prot;
 575         unsigned char *map=MAP_FAILED, *base;
 576         size_t dyn=0;
 577         size_t tls_image=0;
 578         size_t i;
 579
 580         ssize_t l = read(fd, buf, sizeof buf);
 581         eh = buf;
 582         if (l<0) return 0;
 583         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 584                 goto noexec;
 585         phsize = eh->e_phentsize * eh->e_phnum;
 586         if (phsize > sizeof buf - sizeof *eh) {
 587                 allocated_buf = malloc(phsize);
 588                 if (!allocated_buf) return 0;
 589                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 590                 if (l < 0) goto error;
 591                 if (l != phsize) goto noexec;
 592                 ph = ph0 = allocated_buf;
 593         } else if (eh->e_phoff + phsize > l) {
 594                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 595                 if (l < 0) goto error;
 596                 if (l != phsize) goto noexec;
 597                 ph = ph0 = (void *)(buf + 1);
 598         } else {
 599                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 600         }
 601         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 602                 if (ph->p_type == PT_DYNAMIC) {
 603                         dyn = ph->p_vaddr;
 604                 } else if (ph->p_type == PT_TLS) {
 605                         tls_image = ph->p_vaddr;
 606                         dso->tls.align = ph->p_align;
 607                         dso->tls.len = ph->p_filesz;
 608                         dso->tls.size = ph->p_memsz;
 609                 } else if (ph->p_type == PT_GNU_RELRO) {
 610                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 611                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 612                 }
 613                 if (ph->p_type != PT_LOAD) continue;
 614                 nsegs++;
 615                 if (ph->p_vaddr < addr_min) {
 616                         addr_min = ph->p_vaddr;
 617                         off_start = ph->p_offset;
 618                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 619                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 620                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 621                 }
 622                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 623                         addr_max = ph->p_vaddr+ph->p_memsz;
 624                 }
 625         }
 626         if (!dyn) goto noexec;
 627         if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
 628                 dso->loadmap = calloc(1, sizeof *dso->loadmap
 629                         + nsegs * sizeof *dso->loadmap->segs);
 630                 if (!dso->loadmap) goto error;
 631                 dso->loadmap->nsegs = nsegs;
 632                 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
 633                         if (ph->p_type != PT_LOAD) continue;
 634                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 635                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 636                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 637                         map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
 638                                 prot, MAP_PRIVATE,
 639                                 fd, ph->p_offset & -PAGE_SIZE);
 640                         if (map == MAP_FAILED) {
 641                                 unmap_library(dso);
 642                                 goto error;
 643                         }
 644                         dso->loadmap->segs[i].addr = (size_t)map +
 645                                 (ph->p_vaddr & PAGE_SIZE-1);
 646                         dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
 647                         dso->loadmap->segs[i].p_memsz = ph->p_memsz;
 648                         i++;
 649                         if (prot & PROT_WRITE) {
 650                                 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
 651                                         + ph->p_filesz;
 652                                 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
 653                                 size_t pgend = brk + ph->p_memsz - ph->p_filesz
 654                                         + PAGE_SIZE-1 & -PAGE_SIZE;
 655                                 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
 656                                         pgend-pgbrk, prot,
 657                                         MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
 658                                         -1, off_start) == MAP_FAILED)
 659                                         goto error;
 660                                 memset(map + brk, 0, pgbrk-brk);
 661                         }
 662                 }
 663                 map = (void *)dso->loadmap->segs[0].addr;
 664                 map_len = 0;
 665                 goto done_mapping;
 666         }
 667         addr_max += PAGE_SIZE-1;
 668         addr_max &= -PAGE_SIZE;
 669         addr_min &= -PAGE_SIZE;
 670         off_start &= -PAGE_SIZE;
 671         map_len = addr_max - addr_min + off_start;
 672         /* The first time, we map too much, possibly even more than
 673          * the length of the file. This is okay because we will not
 674          * use the invalid part; we just need to reserve the right
 675          * amount of virtual address space to map over later. */
 676         map = DL_NOMMU_SUPPORT
 677                 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
 678                         MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
 679                 : mmap((void *)addr_min, map_len, prot,
 680                         MAP_PRIVATE, fd, off_start);
 681         if (map==MAP_FAILED) goto error;
 682         dso->map = map;
 683         dso->map_len = map_len;
 684         /* If the loaded file is not relocatable and the requested address is
 685          * not available, then the load operation must fail. */
 686         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 687                 errno = EBUSY;
 688                 goto error;
 689         }
 690         base = map - addr_min;
 691         dso->phdr = 0;
 692         dso->phnum = 0;
 693         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 694                 if (ph->p_type != PT_LOAD) continue;
 695                 /* Check if the programs headers are in this load segment, and
 696                  * if so, record the address for use by dl_iterate_phdr. */
 697                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 698                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 699                         dso->phdr = (void *)(base + ph->p_vaddr
 700                                 + (eh->e_phoff-ph->p_offset));
 701                         dso->phnum = eh->e_phnum;
 702                         dso->phentsize = eh->e_phentsize;
 703                 }
 704                 /* Reuse the existing mapping for the lowest-address LOAD */
 705                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min && !DL_NOMMU_SUPPORT)
 706                         continue;
 707                 this_min = ph->p_vaddr & -PAGE_SIZE;
 708                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 709                 off_start = ph->p_offset & -PAGE_SIZE;
 710                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 711                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 712                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 713                 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 714                         goto error;
 715                 if (ph->p_memsz > ph->p_filesz) {
 716                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 717                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 718                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 719                         if (pgbrk-(size_t)base < this_max && mmap_fixed((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED)
 720                                 goto error;
 721                 }
 722         }
 723         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 724                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 725                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
 726                             && errno != ENOSYS)
 727                                 goto error;
 728                         break;
 729                 }
 730 done_mapping:
 731         dso->base = base;
 732         dso->dynv = laddr(dso, dyn);
 733         if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
 734         if (!runtime) reclaim_gaps(dso);
 735         free(allocated_buf);
 736         return map;
 737 noexec:
 738         errno = ENOEXEC;
 739 error:
 740         if (map!=MAP_FAILED) unmap_library(dso);
 741         free(allocated_buf);
 742         return 0;
 743 }
 744
 745 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 746 {
 747         size_t l;
 748         int fd;
 749         for (;;) {
 750                 s += strspn(s, ":\n");
 751                 l = strcspn(s, ":\n");
 752                 if (l-1 >= INT_MAX) return -1;
 753                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
 754                         if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 755                         switch (errno) {
 756                         case ENOENT:
 757                         case ENOTDIR:
 758                         case EACCES:
 759                         case ENAMETOOLONG:
 760                                 break;
 761                         default:
 762                                 /* Any negative value but -1 will inhibit
 763                                  * futher path search. */
 764                                 return -2;
 765                         }
 766                 }
 767                 s += l;
 768         }
 769 }
 770
 771 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 772 {
 773         size_t n, l;
 774         const char *s, *t, *origin;
 775         char *d;
 776         if (p->rpath || !p->rpath_orig) return 0;
 777         if (!strchr(p->rpath_orig, '$')) {
 778                 p->rpath = p->rpath_orig;
 779                 return 0;
 780         }
 781         n = 0;
 782         s = p->rpath_orig;
 783         while ((t=strchr(s, '$'))) {
 784                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 785                         return 0;
 786                 s = t+1;
 787                 n++;
 788         }
 789         if (n > SSIZE_MAX/PATH_MAX) return 0;
 790
 791         if (p->kernel_mapped) {
 792                 /* $ORIGIN searches cannot be performed for the main program
 793                  * when it is suid/sgid/AT_SECURE. This is because the
 794                  * pathname is under the control of the caller of execve.
 795                  * For libraries, however, $ORIGIN can be processed safely
 796                  * since the library's pathname came from a trusted source
 797                  * (either system paths or a call to dlopen). */
 798                 if (libc.secure)
 799                         return 0;
 800                 l = readlink("/proc/self/exe", buf, buf_size);
 801                 if (l == -1) switch (errno) {
 802                 case ENOENT:
 803                 case ENOTDIR:
 804                 case EACCES:
 805                         break;
 806                 default:
 807                         return -1;
 808                 }
 809                 if (l >= buf_size)
 810                         return 0;
 811                 buf[l] = 0;
 812                 origin = buf;
 813         } else {
 814                 origin = p->name;
 815         }
 816         t = strrchr(origin, '/');
 817         l = t ? t-origin : 0;
 818         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 819         if (!p->rpath) return -1;
 820
 821         d = p->rpath;
 822         s = p->rpath_orig;
 823         while ((t=strchr(s, '$'))) {
 824                 memcpy(d, s, t-s);
 825                 d += t-s;
 826                 memcpy(d, origin, l);
 827                 d += l;
 828                 /* It was determined previously that the '$' is followed
 829                  * either by "ORIGIN" or "{ORIGIN}". */
 830                 s = t + 7 + 2*(t[1]=='{');
 831         }
 832         strcpy(d, s);
 833         return 0;
 834 }
 835
 836 static void decode_dyn(struct dso *p)
 837 {
 838         size_t dyn[DYN_CNT];
 839         decode_vec(p->dynv, dyn, DYN_CNT);
 840         p->syms = laddr(p, dyn[DT_SYMTAB]);
 841         p->strings = laddr(p, dyn[DT_STRTAB]);
 842         if (dyn[0]&(1<<DT_HASH))
 843                 p->hashtab = laddr(p, dyn[DT_HASH]);
 844         if (dyn[0]&(1<<DT_RPATH))
 845                 p->rpath_orig = p->strings + dyn[DT_RPATH];
 846         if (dyn[0]&(1<<DT_RUNPATH))
 847                 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
 848         if (dyn[0]&(1<<DT_PLTGOT))
 849                 p->got = laddr(p, dyn[DT_PLTGOT]);
 850         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 851                 p->ghashtab = laddr(p, *dyn);
 852         if (search_vec(p->dynv, dyn, DT_VERSYM))
 853                 p->versym = laddr(p, *dyn);
 854 }
 855
 856 static size_t count_syms(struct dso *p)
 857 {
 858         if (p->hashtab) return p->hashtab[1];
 859
 860         size_t nsym, i;
 861         uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
 862         uint32_t *hashval;
 863         for (i = nsym = 0; i < p->ghashtab[0]; i++) {
 864                 if (buckets[i] > nsym)
 865                         nsym = buckets[i];
 866         }
 867         if (nsym) {
 868                 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
 869                 do nsym++;
 870                 while (!(*hashval++ & 1));
 871         }
 872         return nsym;
 873 }
 874
 875 static void *dl_mmap(size_t n)
 876 {
 877         void *p;
 878         int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
 879 #ifdef SYS_mmap2
 880         p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
 881 #else
 882         p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
 883 #endif
 884         return p == MAP_FAILED ? 0 : p;
 885 }
 886
 887 static void makefuncdescs(struct dso *p)
 888 {
 889         static int self_done;
 890         size_t nsym = count_syms(p);
 891         size_t i, size = nsym * sizeof(*p->funcdescs);
 892
 893         if (!self_done) {
 894                 p->funcdescs = dl_mmap(size);
 895                 self_done = 1;
 896         } else {
 897                 p->funcdescs = malloc(size);
 898         }
 899         if (!p->funcdescs) {
 900                 if (!runtime) a_crash();
 901                 error("Error allocating function descriptors for %s", p->name);
 902                 longjmp(*rtld_fail, 1);
 903         }
 904         for (i=0; i<nsym; i++) {
 905                 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
 906                         p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
 907                         p->funcdescs[i].got = p->got;
 908                 } else {
 909                         p->funcdescs[i].addr = 0;
 910                         p->funcdescs[i].got = 0;
 911                 }
 912         }
 913 }
 914
 915 static struct dso *load_library(const char *name, struct dso *needed_by)
 916 {
 917         char buf[2*NAME_MAX+2];
 918         const char *pathname;
 919         unsigned char *map;
 920         struct dso *p, temp_dso = {0};
 921         int fd;
 922         struct stat st;
 923         size_t alloc_size;
 924         int n_th = 0;
 925         int is_self = 0;
 926
 927         if (!*name) {
 928                 errno = EINVAL;
 929                 return 0;
 930         }
 931
 932         /* Catch and block attempts to reload the implementation itself */
 933         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 934                 static const char reserved[] =
 935                         "c.pthread.rt.m.dl.util.xnet.";
 936                 const char *rp, *next;
 937                 for (rp=reserved; *rp; rp=next) {
 938                         next = strchr(rp, '.') + 1;
 939                         if (strncmp(name+3, rp, next-rp) == 0)
 940                                 break;
 941                 }
 942                 if (*rp) {
 943                         if (ldd_mode) {
 944                                 /* Track which names have been resolved
 945                                  * and only report each one once. */
 946                                 static unsigned reported;
 947                                 unsigned mask = 1U<<(rp-reserved);
 948                                 if (!(reported & mask)) {
 949                                         reported |= mask;
 950                                         dprintf(1, "\t%s => %s (%p)\n",
 951                                                 name, ldso.name,
 952                                                 ldso.base);
 953                                 }
 954                         }
 955                         is_self = 1;
 956                 }
 957         }
 958         if (!strcmp(name, ldso.name)) is_self = 1;
 959         if (is_self) {
 960                 if (!ldso.prev) {
 961                         tail->next = &ldso;
 962                         ldso.prev = tail;
 963                         tail = &ldso;
 964                 }
 965                 return &ldso;
 966         }
 967         if (strchr(name, '/')) {
 968                 pathname = name;
 969                 fd = open(name, O_RDONLY|O_CLOEXEC);
 970         } else {
 971                 /* Search for the name to see if it's already loaded */
 972                 for (p=head->next; p; p=p->next) {
 973                         if (p->shortname && !strcmp(p->shortname, name)) {
 974                                 p->refcnt++;
 975                                 return p;
 976                         }
 977                 }
 978                 if (strlen(name) > NAME_MAX) return 0;
 979                 fd = -1;
 980                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 981                 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
 982                         if (fixup_rpath(p, buf, sizeof buf) < 0)
 983                                 fd = -2; /* Inhibit further search. */
 984                         if (p->rpath)
 985                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 986                 }
 987                 if (fd == -1) {
 988                         if (!sys_path) {
 989                                 char *prefix = 0;
 990                                 size_t prefix_len;
 991                                 if (ldso.name[0]=='/') {
 992                                         char *s, *t, *z;
 993                                         for (s=t=z=ldso.name; *s; s++)
 994                                                 if (*s=='/') z=t, t=s;
 995                                         prefix_len = z-ldso.name;
 996                                         if (prefix_len < PATH_MAX)
 997                                                 prefix = ldso.name;
 998                                 }
 999                                 if (!prefix) {
1000                                         prefix = "";
1001                                         prefix_len = 0;
1002                                 }
1003                                 char etc_ldso_path[prefix_len + 1
1004                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1005                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1006                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1007                                         (int)prefix_len, prefix);
1008                                 FILE *f = fopen(etc_ldso_path, "rbe");
1009                                 if (f) {
1010                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1011                                                 free(sys_path);
1012                                                 sys_path = "";
1013                                         }
1014                                         fclose(f);
1015                                 } else if (errno != ENOENT) {
1016                                         sys_path = "";
1017                                 }
1018                         }
1019                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1020                         fd = path_open(name, sys_path, buf, sizeof buf);
1021                 }
1022                 pathname = buf;
1023         }
1024         if (fd < 0) return 0;
1025         if (fstat(fd, &st) < 0) {
1026                 close(fd);
1027                 return 0;
1028         }
1029         for (p=head->next; p; p=p->next) {
1030                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1031                         /* If this library was previously loaded with a
1032                          * pathname but a search found the same inode,
1033                          * setup its shortname so it can be found by name. */
1034                         if (!p->shortname && pathname != name)
1035                                 p->shortname = strrchr(p->name, '/')+1;
1036                         close(fd);
1037                         p->refcnt++;
1038                         return p;
1039                 }
1040         }
1041         map = noload ? 0 : map_library(fd, &temp_dso);
1042         close(fd);
1043         if (!map) return 0;
1044
1045         /* Avoid the danger of getting two versions of libc mapped into the
1046          * same process when an absolute pathname was used. The symbols
1047          * checked are chosen to catch both musl and glibc, and to avoid
1048          * false positives from interposition-hack libraries. */
1049         decode_dyn(&temp_dso);
1050         if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1051             find_sym(&temp_dso, "stdin", 1).sym) {
1052                 unmap_library(&temp_dso);
1053                 return load_library("libc.so", needed_by);
1054         }
1055
1056         /* Allocate storage for the new DSO. When there is TLS, this
1057          * storage must include a reservation for all pre-existing
1058          * threads to obtain copies of both the new TLS, and an
1059          * extended DTV capable of storing an additional slot for
1060          * the newly-loaded DSO. */
1061         alloc_size = sizeof *p + strlen(pathname) + 1;
1062         if (runtime && temp_dso.tls.image) {
1063                 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1064                         + sizeof(void *) * (tls_cnt+3);
1065                 n_th = libc.threads_minus_1 + 1;
1066                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1067                 else alloc_size += n_th * per_th;
1068         }
1069         p = calloc(1, alloc_size);
1070         if (!p) {
1071                 unmap_library(&temp_dso);
1072                 return 0;
1073         }
1074         memcpy(p, &temp_dso, sizeof temp_dso);
1075         p->dev = st.st_dev;
1076         p->ino = st.st_ino;
1077         p->refcnt = 1;
1078         p->needed_by = needed_by;
1079         p->name = p->buf;
1080         strcpy(p->name, pathname);
1081         /* Add a shortname only if name arg was not an explicit pathname. */
1082         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1083         if (p->tls.image) {
1084                 p->tls_id = ++tls_cnt;
1085                 tls_align = MAXP2(tls_align, p->tls.align);
1086 #ifdef TLS_ABOVE_TP
1087                 p->tls.offset = tls_offset + ( (tls_align-1) &
1088                         -(tls_offset + (uintptr_t)p->tls.image) );
1089                 tls_offset += p->tls.size;
1090 #else
1091                 tls_offset += p->tls.size + p->tls.align - 1;
1092                 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1093                         & (p->tls.align-1);
1094                 p->tls.offset = tls_offset;
1095 #endif
1096                 p->new_dtv = (void *)(-sizeof(size_t) &
1097                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1098                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1099                 if (tls_tail) tls_tail->next = &p->tls;
1100                 else libc.tls_head = &p->tls;
1101                 tls_tail = &p->tls;
1102         }
1103
1104         tail->next = p;
1105         p->prev = tail;
1106         tail = p;
1107
1108         if (DL_FDPIC) makefuncdescs(p);
1109
1110         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1111
1112         return p;
1113 }
1114
1115 static void load_deps(struct dso *p)
1116 {
1117         size_t i, ndeps=0;
1118         struct dso ***deps = &p->deps, **tmp, *dep;
1119         for (; p; p=p->next) {
1120                 for (i=0; p->dynv[i]; i+=2) {
1121                         if (p->dynv[i] != DT_NEEDED) continue;
1122                         dep = load_library(p->strings + p->dynv[i+1], p);
1123                         if (!dep) {
1124                                 error("Error loading shared library %s: %m (needed by %s)",
1125                                         p->strings + p->dynv[i+1], p->name);
1126                                 if (runtime) longjmp(*rtld_fail, 1);
1127                                 continue;
1128                         }
1129                         if (runtime) {
1130                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1131                                 if (!tmp) longjmp(*rtld_fail, 1);
1132                                 tmp[ndeps++] = dep;
1133                                 tmp[ndeps] = 0;
1134                                 *deps = tmp;
1135                         }
1136                 }
1137         }
1138 }
1139
1140 static void load_preload(char *s)
1141 {
1142         int tmp;
1143         char *z;
1144         for (z=s; *z; s=z) {
1145                 for (   ; *s && (isspace(*s) || *s==':'); s++);
1146                 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1147                 tmp = *z;
1148                 *z = 0;
1149                 load_library(s, 0);
1150                 *z = tmp;
1151         }
1152 }
1153
1154 static void add_syms(struct dso *p)
1155 {
1156         if (!p->syms_next && syms_tail != p) {
1157                 syms_tail->syms_next = p;
1158                 syms_tail = p;
1159         }
1160 }
1161
1162 static void revert_syms(struct dso *old_tail)
1163 {
1164         struct dso *p, *next;
1165         /* Chop off the tail of the list of dsos that participate in
1166          * the global symbol table, reverting them to RTLD_LOCAL. */
1167         for (p=old_tail; p; p=next) {
1168                 next = p->syms_next;
1169                 p->syms_next = 0;
1170         }
1171         syms_tail = old_tail;
1172 }
1173
1174 static void do_mips_relocs(struct dso *p, size_t *got)
1175 {
1176         size_t i, j, rel[2];
1177         unsigned char *base = p->base;
1178         i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1179         if (p==&ldso) {
1180                 got += i;
1181         } else {
1182                 while (i--) *got++ += (size_t)base;
1183         }
1184         j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1185         i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1186         Sym *sym = p->syms + j;
1187         rel[0] = (unsigned char *)got - base;
1188         for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1189                 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1190                 do_relocs(p, rel, sizeof rel, 2);
1191         }
1192 }
1193
1194 static void reloc_all(struct dso *p)
1195 {
1196         size_t dyn[DYN_CNT];
1197         for (; p; p=p->next) {
1198                 if (p->relocated) continue;
1199                 decode_vec(p->dynv, dyn, DYN_CNT);
1200                 if (NEED_MIPS_GOT_RELOCS)
1201                         do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1202                 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1203                         2+(dyn[DT_PLTREL]==DT_RELA));
1204                 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1205                 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1206
1207                 if (head != &ldso && p->relro_start != p->relro_end &&
1208                     mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1209                     && errno != ENOSYS) {
1210                         error("Error relocating %s: RELRO protection failed: %m",
1211                                 p->name);
1212                         if (runtime) longjmp(*rtld_fail, 1);
1213                 }
1214
1215                 p->relocated = 1;
1216         }
1217 }
1218
1219 static void kernel_mapped_dso(struct dso *p)
1220 {
1221         size_t min_addr = -1, max_addr = 0, cnt;
1222         Phdr *ph = p->phdr;
1223         for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1224                 if (ph->p_type == PT_DYNAMIC) {
1225                         p->dynv = laddr(p, ph->p_vaddr);
1226                 } else if (ph->p_type == PT_GNU_RELRO) {
1227                         p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1228                         p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1229                 }
1230                 if (ph->p_type != PT_LOAD) continue;
1231                 if (ph->p_vaddr < min_addr)
1232                         min_addr = ph->p_vaddr;
1233                 if (ph->p_vaddr+ph->p_memsz > max_addr)
1234                         max_addr = ph->p_vaddr+ph->p_memsz;
1235         }
1236         min_addr &= -PAGE_SIZE;
1237         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1238         p->map = p->base + min_addr;
1239         p->map_len = max_addr - min_addr;
1240         p->kernel_mapped = 1;
1241 }
1242
1243 void __libc_exit_fini()
1244 {
1245         struct dso *p;
1246         size_t dyn[DYN_CNT];
1247         for (p=fini_head; p; p=p->fini_next) {
1248                 if (!p->constructed) continue;
1249                 decode_vec(p->dynv, dyn, DYN_CNT);
1250                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1251                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1252                         size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1253                         while (n--) ((void (*)(void))*--fn)();
1254                 }
1255 #ifndef NO_LEGACY_INITFINI
1256                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1257                         fpaddr(p, dyn[DT_FINI])();
1258 #endif
1259         }
1260 }
1261
1262 static void do_init_fini(struct dso *p)
1263 {
1264         size_t dyn[DYN_CNT];
1265         int need_locking = libc.threads_minus_1;
1266         /* Allow recursive calls that arise when a library calls
1267          * dlopen from one of its constructors, but block any
1268          * other threads until all ctors have finished. */
1269         if (need_locking) pthread_mutex_lock(&init_fini_lock);
1270         for (; p; p=p->prev) {
1271                 if (p->constructed) continue;
1272                 p->constructed = 1;
1273                 decode_vec(p->dynv, dyn, DYN_CNT);
1274                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1275                         p->fini_next = fini_head;
1276                         fini_head = p;
1277                 }
1278 #ifndef NO_LEGACY_INITFINI
1279                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1280                         fpaddr(p, dyn[DT_INIT])();
1281 #endif
1282                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1283                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1284                         size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1285                         while (n--) ((void (*)(void))*fn++)();
1286                 }
1287                 if (!need_locking && libc.threads_minus_1) {
1288                         need_locking = 1;
1289                         pthread_mutex_lock(&init_fini_lock);
1290                 }
1291         }
1292         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1293 }
1294
1295 void __libc_start_init(void)
1296 {
1297         do_init_fini(tail);
1298 }
1299
1300 static void dl_debug_state(void)
1301 {
1302 }
1303
1304 weak_alias(dl_debug_state, _dl_debug_state);
1305
1306 void __init_tls(size_t *auxv)
1307 {
1308 }
1309
1310 __attribute__((__visibility__("hidden")))
1311 void *__tls_get_new(tls_mod_off_t *v)
1312 {
1313         pthread_t self = __pthread_self();
1314
1315         /* Block signals to make accessing new TLS async-signal-safe */
1316         sigset_t set;
1317         __block_all_sigs(&set);
1318         if (v[0]<=(size_t)self->dtv[0]) {
1319                 __restore_sigs(&set);
1320                 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1321         }
1322
1323         /* This is safe without any locks held because, if the caller
1324          * is able to request the Nth entry of the DTV, the DSO list
1325          * must be valid at least that far out and it was synchronized
1326          * at program startup or by an already-completed call to dlopen. */
1327         struct dso *p;
1328         for (p=head; p->tls_id != v[0]; p=p->next);
1329
1330         /* Get new DTV space from new DSO if needed */
1331         if (v[0] > (size_t)self->dtv[0]) {
1332                 void **newdtv = p->new_dtv +
1333                         (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
1334                 memcpy(newdtv, self->dtv,
1335                         ((size_t)self->dtv[0]+1) * sizeof(void *));
1336                 newdtv[0] = (void *)v[0];
1337                 self->dtv = self->dtv_copy = newdtv;
1338         }
1339
1340         /* Get new TLS memory from all new DSOs up to the requested one */
1341         unsigned char *mem;
1342         for (p=head; ; p=p->next) {
1343                 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1344                 mem = p->new_tls + (p->tls.size + p->tls.align)
1345                         * a_fetch_add(&p->new_tls_idx,1);
1346                 mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1347                         & (p->tls.align-1);
1348                 self->dtv[p->tls_id] = mem;
1349                 memcpy(mem, p->tls.image, p->tls.len);
1350                 if (p->tls_id == v[0]) break;
1351         }
1352         __restore_sigs(&set);
1353         return mem + v[1] + DTP_OFFSET;
1354 }
1355
1356 static void update_tls_size()
1357 {
1358         libc.tls_cnt = tls_cnt;
1359         libc.tls_align = tls_align;
1360         libc.tls_size = ALIGN(
1361                 (1+tls_cnt) * sizeof(void *) +
1362                 tls_offset +
1363                 sizeof(struct pthread) +
1364                 tls_align * 2,
1365         tls_align);
1366 }
1367
1368 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1369  * following stage 2 and stage 3 functions via primitive symbolic lookup
1370  * since it does not have access to their addresses to begin with. */
1371
1372 /* Stage 2 of the dynamic linker is called after relative relocations
1373  * have been processed. It can make function calls to static functions
1374  * and access string literals and static data, but cannot use extern
1375  * symbols. Its job is to perform symbolic relocations on the dynamic
1376  * linker itself, but some of the relocations performed may need to be
1377  * replaced later due to copy relocations in the main program. */
1378
1379 __attribute__((__visibility__("hidden")))
1380 void __dls2(unsigned char *base, size_t *sp)
1381 {
1382         if (DL_FDPIC) {
1383                 void *p1 = (void *)sp[-2];
1384                 void *p2 = (void *)sp[-1];
1385                 if (!p1) {
1386                         size_t *auxv, aux[AUX_CNT];
1387                         for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1388                         decode_vec(auxv, aux, AUX_CNT);
1389                         if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1390                         else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1391                 }
1392                 app_loadmap = p2 ? p1 : 0;
1393                 ldso.loadmap = p2 ? p2 : p1;
1394                 ldso.base = laddr(&ldso, 0);
1395         } else {
1396                 ldso.base = base;
1397         }
1398         Ehdr *ehdr = (void *)ldso.base;
1399         ldso.name = ldso.shortname = "libc.so";
1400         ldso.phnum = ehdr->e_phnum;
1401         ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1402         ldso.phentsize = ehdr->e_phentsize;
1403         kernel_mapped_dso(&ldso);
1404         decode_dyn(&ldso);
1405
1406         if (DL_FDPIC) makefuncdescs(&ldso);
1407
1408         /* Prepare storage for to save clobbered REL addends so they
1409          * can be reused in stage 3. There should be very few. If
1410          * something goes wrong and there are a huge number, abort
1411          * instead of risking stack overflow. */
1412         size_t dyn[DYN_CNT];
1413         decode_vec(ldso.dynv, dyn, DYN_CNT);
1414         size_t *rel = laddr(&ldso, dyn[DT_REL]);
1415         size_t rel_size = dyn[DT_RELSZ];
1416         size_t symbolic_rel_cnt = 0;
1417         apply_addends_to = rel;
1418         for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1419                 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1420         if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1421         size_t addends[symbolic_rel_cnt+1];
1422         saved_addends = addends;
1423
1424         head = &ldso;
1425         reloc_all(&ldso);
1426
1427         ldso.relocated = 0;
1428
1429         /* Call dynamic linker stage-3, __dls3, looking it up
1430          * symbolically as a barrier against moving the address
1431          * load across the above relocation processing. */
1432         struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1433         if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1434         else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1435 }
1436
1437 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1438  * fully functional. Its job is to load (if not already loaded) and
1439  * process dependencies and relocations for the main application and
1440  * transfer control to its entry point. */
1441
1442 _Noreturn void __dls3(size_t *sp)
1443 {
1444         static struct dso app, vdso;
1445         size_t aux[AUX_CNT], *auxv;
1446         size_t i;
1447         char *env_preload=0;
1448         size_t vdso_base;
1449         int argc = *sp;
1450         char **argv = (void *)(sp+1);
1451         char **argv_orig = argv;
1452         char **envp = argv+argc+1;
1453
1454         /* Find aux vector just past environ[] and use it to initialize
1455          * global data that may be needed before we can make syscalls. */
1456         __environ = envp;
1457         for (i=argc+1; argv[i]; i++);
1458         libc.auxv = auxv = (void *)(argv+i+1);
1459         decode_vec(auxv, aux, AUX_CNT);
1460         __hwcap = aux[AT_HWCAP];
1461         libc.page_size = aux[AT_PAGESZ];
1462         libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1463                 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1464
1465         /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1466          * use during dynamic linking. If possible it will also serve as the
1467          * thread pointer at runtime. */
1468         libc.tls_size = sizeof builtin_tls;
1469         libc.tls_align = tls_align;
1470         if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1471                 a_crash();
1472         }
1473
1474         /* Only trust user/env if kernel says we're not suid/sgid */
1475         if (!libc.secure) {
1476                 env_path = getenv("LD_LIBRARY_PATH");
1477                 env_preload = getenv("LD_PRELOAD");
1478         }
1479
1480         /* If the main program was already loaded by the kernel,
1481          * AT_PHDR will point to some location other than the dynamic
1482          * linker's program headers. */
1483         if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1484                 size_t interp_off = 0;
1485                 size_t tls_image = 0;
1486                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1487                 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1488                 app.phnum = aux[AT_PHNUM];
1489                 app.phentsize = aux[AT_PHENT];
1490                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1491                         if (phdr->p_type == PT_PHDR)
1492                                 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1493                         else if (phdr->p_type == PT_INTERP)
1494                                 interp_off = (size_t)phdr->p_vaddr;
1495                         else if (phdr->p_type == PT_TLS) {
1496                                 tls_image = phdr->p_vaddr;
1497                                 app.tls.len = phdr->p_filesz;
1498                                 app.tls.size = phdr->p_memsz;
1499                                 app.tls.align = phdr->p_align;
1500                         }
1501                 }
1502                 if (DL_FDPIC) app.loadmap = app_loadmap;
1503                 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1504                 if (interp_off) ldso.name = laddr(&app, interp_off);
1505                 if ((aux[0] & (1UL<<AT_EXECFN))
1506                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1507                         app.name = (char *)aux[AT_EXECFN];
1508                 else
1509                         app.name = argv[0];
1510                 kernel_mapped_dso(&app);
1511         } else {
1512                 int fd;
1513                 char *ldname = argv[0];
1514                 size_t l = strlen(ldname);
1515                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1516                 argv++;
1517                 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1518                         char *opt = argv[0]+2;
1519                         *argv++ = (void *)-1;
1520                         if (!*opt) {
1521                                 break;
1522                         } else if (!memcmp(opt, "list", 5)) {
1523                                 ldd_mode = 1;
1524                         } else if (!memcmp(opt, "library-path", 12)) {
1525                                 if (opt[12]=='=') env_path = opt+13;
1526                                 else if (opt[12]) *argv = 0;
1527                                 else if (*argv) env_path = *argv++;
1528                         } else if (!memcmp(opt, "preload", 7)) {
1529                                 if (opt[7]=='=') env_preload = opt+8;
1530                                 else if (opt[7]) *argv = 0;
1531                                 else if (*argv) env_preload = *argv++;
1532                         } else {
1533                                 argv[0] = 0;
1534                         }
1535                 }
1536                 argv[-1] = (void *)(argc - (argv-argv_orig));
1537                 if (!argv[0]) {
1538                         dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1539                                 "Version %s\n"
1540                                 "Dynamic Program Loader\n"
1541                                 "Usage: %s [options] [--] pathname%s\n",
1542                                 __libc_get_version(), ldname,
1543                                 ldd_mode ? "" : " [args]");
1544                         _exit(1);
1545                 }
1546                 fd = open(argv[0], O_RDONLY);
1547                 if (fd < 0) {
1548                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1549                         _exit(1);
1550                 }
1551                 runtime = 1;
1552                 Ehdr *ehdr = (void *)map_library(fd, &app);
1553                 if (!ehdr) {
1554                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1555                         _exit(1);
1556                 }
1557                 runtime = 0;
1558                 close(fd);
1559                 ldso.name = ldname;
1560                 app.name = argv[0];
1561                 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1562                 /* Find the name that would have been used for the dynamic
1563                  * linker had ldd not taken its place. */
1564                 if (ldd_mode) {
1565                         for (i=0; i<app.phnum; i++) {
1566                                 if (app.phdr[i].p_type == PT_INTERP)
1567                                         ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1568                         }
1569                         dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1570                 }
1571         }
1572         if (app.tls.size) {
1573                 libc.tls_head = tls_tail = &app.tls;
1574                 app.tls_id = tls_cnt = 1;
1575 #ifdef TLS_ABOVE_TP
1576                 app.tls.offset = 0;
1577                 tls_offset = app.tls.size
1578                         + ( -((uintptr_t)app.tls.image + app.tls.size)
1579                         & (app.tls.align-1) );
1580 #else
1581                 tls_offset = app.tls.offset = app.tls.size
1582                         + ( -((uintptr_t)app.tls.image + app.tls.size)
1583                         & (app.tls.align-1) );
1584 #endif
1585                 tls_align = MAXP2(tls_align, app.tls.align);
1586         }
1587         decode_dyn(&app);
1588         if (DL_FDPIC) {
1589                 makefuncdescs(&app);
1590                 if (!app.loadmap) {
1591                         app.loadmap = (void *)&app_dummy_loadmap;
1592                         app.loadmap->nsegs = 1;
1593                         app.loadmap->segs[0].addr = (size_t)app.map;
1594                         app.loadmap->segs[0].p_vaddr = (size_t)app.map
1595                                 - (size_t)app.base;
1596                         app.loadmap->segs[0].p_memsz = app.map_len;
1597                 }
1598                 argv[-3] = (void *)app.loadmap;
1599         }
1600
1601         /* Initial dso chain consists only of the app. */
1602         head = tail = syms_tail = &app;
1603
1604         /* Donate unused parts of app and library mapping to malloc */
1605         reclaim_gaps(&app);
1606         reclaim_gaps(&ldso);
1607
1608         /* Load preload/needed libraries, add symbols to global namespace. */
1609         if (env_preload) load_preload(env_preload);
1610         load_deps(&app);
1611         for (struct dso *p=head; p; p=p->next)
1612                 add_syms(p);
1613
1614         /* Attach to vdso, if provided by the kernel, last so that it does
1615          * not become part of the global namespace.  */
1616         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1617                 Ehdr *ehdr = (void *)vdso_base;
1618                 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1619                 vdso.phnum = ehdr->e_phnum;
1620                 vdso.phentsize = ehdr->e_phentsize;
1621                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1622                         if (phdr->p_type == PT_DYNAMIC)
1623                                 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1624                         if (phdr->p_type == PT_LOAD)
1625                                 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1626                 }
1627                 vdso.name = "";
1628                 vdso.shortname = "linux-gate.so.1";
1629                 vdso.relocated = 1;
1630                 decode_dyn(&vdso);
1631                 vdso.prev = tail;
1632                 tail->next = &vdso;
1633                 tail = &vdso;
1634         }
1635
1636         for (i=0; app.dynv[i]; i+=2) {
1637                 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1638                         app.dynv[i+1] = (size_t)&debug;
1639                 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1640                         size_t *ptr = (size_t *) app.dynv[i+1];
1641                         *ptr = (size_t)&debug;
1642                 }
1643         }
1644
1645         /* The main program must be relocated LAST since it may contin
1646          * copy relocations which depend on libraries' relocations. */
1647         reloc_all(app.next);
1648         reloc_all(&app);
1649
1650         update_tls_size();
1651         if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1652                 void *initial_tls = calloc(libc.tls_size, 1);
1653                 if (!initial_tls) {
1654                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1655                                 argv[0], libc.tls_size);
1656                         _exit(127);
1657                 }
1658                 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1659                         a_crash();
1660                 }
1661         } else {
1662                 size_t tmp_tls_size = libc.tls_size;
1663                 pthread_t self = __pthread_self();
1664                 /* Temporarily set the tls size to the full size of
1665                  * builtin_tls so that __copy_tls will use the same layout
1666                  * as it did for before. Then check, just to be safe. */
1667                 libc.tls_size = sizeof builtin_tls;
1668                 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1669                 libc.tls_size = tmp_tls_size;
1670         }
1671         static_tls_cnt = tls_cnt;
1672
1673         if (ldso_fail) _exit(127);
1674         if (ldd_mode) _exit(0);
1675
1676         /* Switch to runtime mode: any further failures in the dynamic
1677          * linker are a reportable failure rather than a fatal startup
1678          * error. */
1679         runtime = 1;
1680
1681         debug.ver = 1;
1682         debug.bp = dl_debug_state;
1683         debug.head = head;
1684         debug.base = ldso.base;
1685         debug.state = 0;
1686         _dl_debug_state();
1687
1688         errno = 0;
1689
1690         CRTJMP((void *)aux[AT_ENTRY], argv-1);
1691         for(;;);
1692 }
1693
1694 static void prepare_lazy(struct dso *p)
1695 {
1696         size_t dyn[DYN_CNT], n, flags1=0;
1697         decode_vec(p->dynv, dyn, DYN_CNT);
1698         search_vec(p->dynv, &flags1, DT_FLAGS_1);
1699         if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1700                 return;
1701         n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1702         if (NEED_MIPS_GOT_RELOCS) {
1703                 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1704                 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1705                 n += i-j;
1706         }
1707         p->lazy = calloc(n, 3*sizeof(size_t));
1708         if (!p->lazy) {
1709                 error("Error preparing lazy relocation for %s: %m", p->name);
1710                 longjmp(*rtld_fail, 1);
1711         }
1712         p->lazy_next = lazy_head;
1713         lazy_head = p;
1714 }
1715
1716 void *dlopen(const char *file, int mode)
1717 {
1718         struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1719         struct tls_module *orig_tls_tail;
1720         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1721         size_t i;
1722         int cs;
1723         jmp_buf jb;
1724
1725         if (!file) return head;
1726
1727         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1728         pthread_rwlock_wrlock(&lock);
1729         __inhibit_ptc();
1730
1731         p = 0;
1732         orig_tls_tail = tls_tail;
1733         orig_tls_cnt = tls_cnt;
1734         orig_tls_offset = tls_offset;
1735         orig_tls_align = tls_align;
1736         orig_lazy_head = lazy_head;
1737         orig_syms_tail = syms_tail;
1738         orig_tail = tail;
1739         noload = mode & RTLD_NOLOAD;
1740
1741         rtld_fail = &jb;
1742         if (setjmp(*rtld_fail)) {
1743                 /* Clean up anything new that was (partially) loaded */
1744                 revert_syms(orig_syms_tail);
1745                 for (p=orig_tail->next; p; p=next) {
1746                         next = p->next;
1747                         while (p->td_index) {
1748                                 void *tmp = p->td_index->next;
1749                                 free(p->td_index);
1750                                 p->td_index = tmp;
1751                         }
1752                         free(p->funcdescs);
1753                         if (p->rpath != p->rpath_orig)
1754                                 free(p->rpath);
1755                         free(p->deps);
1756                         unmap_library(p);
1757                         free(p);
1758                 }
1759                 if (!orig_tls_tail) libc.tls_head = 0;
1760                 tls_tail = orig_tls_tail;
1761                 if (tls_tail) tls_tail->next = 0;
1762                 tls_cnt = orig_tls_cnt;
1763                 tls_offset = orig_tls_offset;
1764                 tls_align = orig_tls_align;
1765                 lazy_head = orig_lazy_head;
1766                 tail = orig_tail;
1767                 tail->next = 0;
1768                 p = 0;
1769                 goto end;
1770         } else p = load_library(file, head);
1771
1772         if (!p) {
1773                 error(noload ?
1774                         "Library %s is not already loaded" :
1775                         "Error loading shared library %s: %m",
1776                         file);
1777                 goto end;
1778         }
1779
1780         /* First load handling */
1781         if (!p->relocated) {
1782                 load_deps(p);
1783                 if ((mode & RTLD_LAZY)) {
1784                         prepare_lazy(p);
1785                         if (p->deps) for (i=0; p->deps[i]; i++)
1786                                 if (!p->deps[i]->relocated)
1787                                         prepare_lazy(p->deps[i]);
1788                 }
1789                 /* Make new symbols global, at least temporarily, so we can do
1790                  * relocations. If not RTLD_GLOBAL, this is reverted below. */
1791                 add_syms(p);
1792                 if (p->deps) for (i=0; p->deps[i]; i++)
1793                         add_syms(p->deps[i]);
1794                 reloc_all(p);
1795         }
1796
1797         /* If RTLD_GLOBAL was not specified, undo any new additions
1798          * to the global symbol table. This is a nop if the library was
1799          * previously loaded and already global. */
1800         if (!(mode & RTLD_GLOBAL))
1801                 revert_syms(orig_syms_tail);
1802
1803         /* Processing of deferred lazy relocations must not happen until
1804          * the new libraries are committed; otherwise we could end up with
1805          * relocations resolved to symbol definitions that get removed. */
1806         redo_lazy_relocs();
1807
1808         update_tls_size();
1809         _dl_debug_state();
1810         orig_tail = tail;
1811 end:
1812         __release_ptc();
1813         if (p) gencnt++;
1814         pthread_rwlock_unlock(&lock);
1815         if (p) do_init_fini(orig_tail);
1816         pthread_setcancelstate(cs, 0);
1817         return p;
1818 }
1819
1820 __attribute__((__visibility__("hidden")))
1821 int __dl_invalid_handle(void *h)
1822 {
1823         struct dso *p;
1824         for (p=head; p; p=p->next) if (h==p) return 0;
1825         error("Invalid library handle %p", (void *)h);
1826         return 1;
1827 }
1828
1829 static void *addr2dso(size_t a)
1830 {
1831         struct dso *p;
1832         size_t i;
1833         if (DL_FDPIC) for (p=head; p; p=p->next) {
1834                 i = count_syms(p);
1835                 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1836                         return p;
1837         }
1838         for (p=head; p; p=p->next) {
1839                 if (DL_FDPIC && p->loadmap) {
1840                         for (i=0; i<p->loadmap->nsegs; i++) {
1841                                 if (a-p->loadmap->segs[i].p_vaddr
1842                                     < p->loadmap->segs[i].p_memsz)
1843                                         return p;
1844                         }
1845                 } else {
1846                         if (a-(size_t)p->map < p->map_len)
1847                                 return p;
1848                 }
1849         }
1850         return 0;
1851 }
1852
1853 void *__tls_get_addr(tls_mod_off_t *);
1854
1855 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1856 {
1857         size_t i;
1858         uint32_t h = 0, gh = 0, *ght;
1859         Sym *sym;
1860         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1861                 if (p == RTLD_DEFAULT) {
1862                         p = head;
1863                 } else if (p == RTLD_NEXT) {
1864                         p = addr2dso((size_t)ra);
1865                         if (!p) p=head;
1866                         p = p->next;
1867                 }
1868                 struct symdef def = find_sym(p, s, 0);
1869                 if (!def.sym) goto failed;
1870                 if ((def.sym->st_info&0xf) == STT_TLS)
1871                         return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value});
1872                 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1873                         return def.dso->funcdescs + (def.sym - def.dso->syms);
1874                 return laddr(def.dso, def.sym->st_value);
1875         }
1876         if (__dl_invalid_handle(p))
1877                 return 0;
1878         if ((ght = p->ghashtab)) {
1879                 gh = gnu_hash(s);
1880                 sym = gnu_lookup(gh, ght, p, s);
1881         } else {
1882                 h = sysv_hash(s);
1883                 sym = sysv_lookup(s, h, p);
1884         }
1885         if (sym && (sym->st_info&0xf) == STT_TLS)
1886                 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value});
1887         if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1888                 return p->funcdescs + (sym - p->syms);
1889         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1890                 return laddr(p, sym->st_value);
1891         if (p->deps) for (i=0; p->deps[i]; i++) {
1892                 if ((ght = p->deps[i]->ghashtab)) {
1893                         if (!gh) gh = gnu_hash(s);
1894                         sym = gnu_lookup(gh, ght, p->deps[i], s);
1895                 } else {
1896                         if (!h) h = sysv_hash(s);
1897                         sym = sysv_lookup(s, h, p->deps[i]);
1898                 }
1899                 if (sym && (sym->st_info&0xf) == STT_TLS)
1900                         return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value});
1901                 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1902                         return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1903                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1904                         return laddr(p->deps[i], sym->st_value);
1905         }
1906 failed:
1907         error("Symbol not found: %s", s);
1908         return 0;
1909 }
1910
1911 int dladdr(const void *addr, Dl_info *info)
1912 {
1913         struct dso *p;
1914         Sym *sym, *bestsym;
1915         uint32_t nsym;
1916         char *strings;
1917         void *best = 0;
1918
1919         pthread_rwlock_rdlock(&lock);
1920         p = addr2dso((size_t)addr);
1921         pthread_rwlock_unlock(&lock);
1922
1923         if (!p) return 0;
1924
1925         sym = p->syms;
1926         strings = p->strings;
1927         nsym = count_syms(p);
1928
1929         if (DL_FDPIC) {
1930                 size_t idx = ((size_t)addr-(size_t)p->funcdescs)
1931                         / sizeof(*p->funcdescs);
1932                 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1933                         best = p->funcdescs + idx;
1934                         bestsym = sym + idx;
1935                 }
1936         }
1937
1938         if (!best) for (; nsym; nsym--, sym++) {
1939                 if (sym->st_value
1940                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1941                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1942                         void *symaddr = laddr(p, sym->st_value);
1943                         if (symaddr > addr || symaddr < best)
1944                                 continue;
1945                         best = symaddr;
1946                         bestsym = sym;
1947                         if (addr == symaddr)
1948                                 break;
1949                 }
1950         }
1951
1952         if (!best) return 0;
1953
1954         if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
1955                 best = p->funcdescs + (bestsym - p->syms);
1956
1957         info->dli_fname = p->name;
1958         info->dli_fbase = p->base;
1959         info->dli_sname = strings + bestsym->st_name;
1960         info->dli_saddr = best;
1961
1962         return 1;
1963 }
1964
1965 __attribute__((__visibility__("hidden")))
1966 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1967 {
1968         void *res;
1969         pthread_rwlock_rdlock(&lock);
1970         res = do_dlsym(p, s, ra);
1971         pthread_rwlock_unlock(&lock);
1972         return res;
1973 }
1974
1975 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1976 {
1977         struct dso *current;
1978         struct dl_phdr_info info;
1979         int ret = 0;
1980         for(current = head; current;) {
1981                 info.dlpi_addr      = (uintptr_t)current->base;
1982                 info.dlpi_name      = current->name;
1983                 info.dlpi_phdr      = current->phdr;
1984                 info.dlpi_phnum     = current->phnum;
1985                 info.dlpi_adds      = gencnt;
1986                 info.dlpi_subs      = 0;
1987                 info.dlpi_tls_modid = current->tls_id;
1988                 info.dlpi_tls_data  = current->tls.image;
1989
1990                 ret = (callback)(&info, sizeof (info), data);
1991
1992                 if (ret != 0) break;
1993
1994                 pthread_rwlock_rdlock(&lock);
1995                 current = current->next;
1996                 pthread_rwlock_unlock(&lock);
1997         }
1998         return ret;
1999 }
2000
2001 __attribute__((__visibility__("hidden")))
2002 void __dl_vseterr(const char *, va_list);
2003
2004 static void error(const char *fmt, ...)
2005 {
2006         va_list ap;
2007         va_start(ap, fmt);
2008         if (!runtime) {
2009                 vdprintf(2, fmt, ap);
2010                 dprintf(2, "\n");
2011                 ldso_fail = 1;
2012                 va_end(ap);
2013                 return;
2014         }
2015         __dl_vseterr(fmt, ap);
2016         va_end(ap);
2017 }