nsz Git - musl/blob - 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         Sym *syms;
  56         Elf_Symndx *hashtab;
  57         uint32_t *ghashtab;
  58         int16_t *versym;
  59         char *strings;
  60         struct dso *syms_next, *lazy_next;
  61         size_t *lazy, lazy_cnt;
  62         unsigned char *map;
  63         size_t map_len;
  64         dev_t dev;
  65         ino_t ino;
  66         char relocated;
  67         char constructed;
  68         char kernel_mapped;
  69         struct dso **deps, *needed_by;
  70         char *rpath_orig, *rpath;
  71         struct tls_module tls;
  72         size_t tls_id;
  73         size_t relro_start, relro_end;
  74         void **new_dtv;
  75         unsigned char *new_tls;
  76         volatile int new_dtv_idx, new_tls_idx;
  77         struct td_index *td_index;
  78         struct dso *fini_next;
  79         char *shortname;
  80 #if DL_FDPIC
  81         unsigned char *base;
  82 #else
  83         struct fdpic_loadmap *loadmap;
  84 #endif
  85         struct funcdesc {
  86                 void *addr;
  87                 size_t *got;
  88         } *funcdescs;
  89         size_t *got;
  90         char buf[];
  91 };
  92
  93 struct symdef {
  94         Sym *sym;
  95         struct dso *dso;
  96 };
  97
  98 int __init_tp(void *);
  99 void __init_libc(char **, char *);
 100 void *__copy_tls(unsigned char *);
 101
 102 __attribute__((__visibility__("hidden")))
 103 const char *__libc_get_version(void);
 104
 105 static struct builtin_tls {
 106         char c;
 107         struct pthread pt;
 108         void *space[16];
 109 } builtin_tls[1];
 110 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
 111
 112 #define ADDEND_LIMIT 4096
 113 static size_t *saved_addends, *apply_addends_to;
 114
 115 static struct dso ldso;
 116 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
 117 static char *env_path, *sys_path;
 118 static unsigned long long gencnt;
 119 static int runtime;
 120 static int ldd_mode;
 121 static int ldso_fail;
 122 static int noload;
 123 static jmp_buf *rtld_fail;
 124 static pthread_rwlock_t lock;
 125 static struct debug debug;
 126 static struct tls_module *tls_tail;
 127 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
 128 static size_t static_tls_cnt;
 129 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 130 static struct fdpic_loadmap *app_loadmap;
 131 static struct fdpic_dummy_loadmap app_dummy_loadmap;
 132 static struct dso *const nodeps_dummy;
 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 = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
 263         size_t ghm = 1ul << gh % (8*sizeof(size_t));
 264         struct symdef def = {0};
 265         for (; dso; dso=dso->syms_next) {
 266                 Sym *sym;
 267                 if ((ght = dso->ghashtab)) {
 268                         sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
 269                 } else {
 270                         if (!h) h = sysv_hash(s);
 271                         sym = sysv_lookup(s, h, dso);
 272                 }
 273                 if (!sym) continue;
 274                 if (!sym->st_shndx)
 275                         if (need_def || (sym->st_info&0xf) == STT_TLS
 276                             || ARCH_SYM_REJECT_UND(sym))
 277                                 continue;
 278                 if (!sym->st_value)
 279                         if ((sym->st_info&0xf) != STT_TLS)
 280                                 continue;
 281                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 282                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 283                 def.sym = sym;
 284                 def.dso = dso;
 285                 break;
 286         }
 287         return def;
 288 }
 289
 290 __attribute__((__visibility__("hidden")))
 291 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
 292
 293 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 294 {
 295         unsigned char *base = dso->base;
 296         Sym *syms = dso->syms;
 297         char *strings = dso->strings;
 298         Sym *sym;
 299         const char *name;
 300         void *ctx;
 301         int type;
 302         int sym_index;
 303         struct symdef def;
 304         size_t *reloc_addr;
 305         size_t sym_val;
 306         size_t tls_val;
 307         size_t addend;
 308         int skip_relative = 0, reuse_addends = 0, save_slot = 0;
 309
 310         if (dso == &ldso) {
 311                 /* Only ldso's REL table needs addend saving/reuse. */
 312                 if (rel == apply_addends_to)
 313                         reuse_addends = 1;
 314                 skip_relative = 1;
 315         }
 316
 317         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 318                 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
 319                 type = R_TYPE(rel[1]);
 320                 if (type == REL_NONE) continue;
 321                 reloc_addr = laddr(dso, rel[0]);
 322
 323                 if (stride > 2) {
 324                         addend = rel[2];
 325                 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
 326                         addend = 0;
 327                 } else if (reuse_addends) {
 328                         /* Save original addend in stage 2 where the dso
 329                          * chain consists of just ldso; otherwise read back
 330                          * saved addend since the inline one was clobbered. */
 331                         if (head==&ldso)
 332                                 saved_addends[save_slot] = *reloc_addr;
 333                         addend = saved_addends[save_slot++];
 334                 } else {
 335                         addend = *reloc_addr;
 336                 }
 337
 338                 sym_index = R_SYM(rel[1]);
 339                 if (sym_index) {
 340                         sym = syms + sym_index;
 341                         name = strings + sym->st_name;
 342                         ctx = type==REL_COPY ? head->syms_next : head;
 343                         def = (sym->st_info&0xf) == STT_SECTION
 344                                 ? (struct symdef){ .dso = dso, .sym = sym }
 345                                 : find_sym(ctx, name, type==REL_PLT);
 346                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 347                             || sym->st_info>>4 != STB_WEAK)) {
 348                                 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
 349                                         dso->lazy[3*dso->lazy_cnt+0] = rel[0];
 350                                         dso->lazy[3*dso->lazy_cnt+1] = rel[1];
 351                                         dso->lazy[3*dso->lazy_cnt+2] = addend;
 352                                         dso->lazy_cnt++;
 353                                         continue;
 354                                 }
 355                                 error("Error relocating %s: %s: symbol not found",
 356                                         dso->name, name);
 357                                 if (runtime) longjmp(*rtld_fail, 1);
 358                                 continue;
 359                         }
 360                 } else {
 361                         sym = 0;
 362                         def.sym = 0;
 363                         def.dso = dso;
 364                 }
 365
 366                 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
 367                 tls_val = def.sym ? def.sym->st_value : 0;
 368
 369                 switch(type) {
 370                 case REL_NONE:
 371                         break;
 372                 case REL_OFFSET:
 373                         addend -= (size_t)reloc_addr;
 374                 case REL_SYMBOLIC:
 375                 case REL_GOT:
 376                 case REL_PLT:
 377                         *reloc_addr = sym_val + addend;
 378                         break;
 379                 case REL_RELATIVE:
 380                         *reloc_addr = (size_t)base + addend;
 381                         break;
 382                 case REL_SYM_OR_REL:
 383                         if (sym) *reloc_addr = sym_val + addend;
 384                         else *reloc_addr = (size_t)base + addend;
 385                         break;
 386                 case REL_COPY:
 387                         memcpy(reloc_addr, (void *)sym_val, sym->st_size);
 388                         break;
 389                 case REL_OFFSET32:
 390                         *(uint32_t *)reloc_addr = sym_val + addend
 391                                 - (size_t)reloc_addr;
 392                         break;
 393                 case REL_FUNCDESC:
 394                         *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
 395                                 + (def.sym - def.dso->syms)) : 0;
 396                         break;
 397                 case REL_FUNCDESC_VAL:
 398                         if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
 399                         else *reloc_addr = sym_val;
 400                         reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
 401                         break;
 402                 case REL_DTPMOD:
 403                         *reloc_addr = def.dso->tls_id;
 404                         break;
 405                 case REL_DTPOFF:
 406                         *reloc_addr = tls_val + addend - DTP_OFFSET;
 407                         break;
 408 #ifdef TLS_ABOVE_TP
 409                 case REL_TPOFF:
 410                         *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
 411                         break;
 412 #else
 413                 case REL_TPOFF:
 414                         *reloc_addr = tls_val - def.dso->tls.offset + addend;
 415                         break;
 416                 case REL_TPOFF_NEG:
 417                         *reloc_addr = def.dso->tls.offset - tls_val + addend;
 418                         break;
 419 #endif
 420                 case REL_TLSDESC:
 421                         if (stride<3) addend = reloc_addr[1];
 422                         if (runtime && def.dso->tls_id >= static_tls_cnt) {
 423                                 struct td_index *new = malloc(sizeof *new);
 424                                 if (!new) {
 425                                         error(
 426                                         "Error relocating %s: cannot allocate TLSDESC for %s",
 427                                         dso->name, sym ? name : "(local)" );
 428                                         longjmp(*rtld_fail, 1);
 429                                 }
 430                                 new->next = dso->td_index;
 431                                 dso->td_index = new;
 432                                 new->args[0] = def.dso->tls_id;
 433                                 new->args[1] = tls_val + addend;
 434                                 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
 435                                 reloc_addr[1] = (size_t)new;
 436                         } else {
 437                                 reloc_addr[0] = (size_t)__tlsdesc_static;
 438 #ifdef TLS_ABOVE_TP
 439                                 reloc_addr[1] = tls_val + def.dso->tls.offset
 440                                         + TPOFF_K + addend;
 441 #else
 442                                 reloc_addr[1] = tls_val - def.dso->tls.offset
 443                                         + addend;
 444 #endif
 445                         }
 446                         break;
 447                 default:
 448                         error("Error relocating %s: unsupported relocation type %d",
 449                                 dso->name, type);
 450                         if (runtime) longjmp(*rtld_fail, 1);
 451                         continue;
 452                 }
 453         }
 454 }
 455
 456 static void redo_lazy_relocs()
 457 {
 458         struct dso *p = lazy_head, *next;
 459         lazy_head = 0;
 460         for (; p; p=next) {
 461                 next = p->lazy_next;
 462                 size_t size = p->lazy_cnt*3*sizeof(size_t);
 463                 p->lazy_cnt = 0;
 464                 do_relocs(p, p->lazy, size, 3);
 465                 if (p->lazy_cnt) {
 466                         p->lazy_next = lazy_head;
 467                         lazy_head = p;
 468                 } else {
 469                         free(p->lazy);
 470                         p->lazy = 0;
 471                         p->lazy_next = 0;
 472                 }
 473         }
 474 }
 475
 476 /* A huge hack: to make up for the wastefulness of shared libraries
 477  * needing at least a page of dirty memory even if they have no global
 478  * data, we reclaim the gaps at the beginning and end of writable maps
 479  * and "donate" them to the heap by setting up minimal malloc
 480  * structures and then freeing them. */
 481
 482 static void reclaim(struct dso *dso, size_t start, size_t end)
 483 {
 484         size_t *a, *z;
 485         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 486         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 487         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 488         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 489         if (start>end || end-start < 4*sizeof(size_t)) return;
 490         a = laddr(dso, start);
 491         z = laddr(dso, end);
 492         a[-2] = 1;
 493         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 494         z[1] = 1;
 495         free(a);
 496 }
 497
 498 static void reclaim_gaps(struct dso *dso)
 499 {
 500         Phdr *ph = dso->phdr;
 501         size_t phcnt = dso->phnum;
 502
 503         if (DL_FDPIC) return; // FIXME
 504         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 505                 if (ph->p_type!=PT_LOAD) continue;
 506                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 507                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 508                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 509                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 510         }
 511 }
 512
 513 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
 514 {
 515         static int no_map_fixed;
 516         char *q;
 517         if (!no_map_fixed) {
 518                 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
 519                 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
 520                         return q;
 521                 no_map_fixed = 1;
 522         }
 523         /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
 524         if (flags & MAP_ANONYMOUS) {
 525                 memset(p, 0, n);
 526                 return p;
 527         }
 528         ssize_t r;
 529         if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
 530         for (q=p; n; q+=r, off+=r, n-=r) {
 531                 r = read(fd, q, n);
 532                 if (r < 0 && errno != EINTR) return MAP_FAILED;
 533                 if (!r) {
 534                         memset(q, 0, n);
 535                         break;
 536                 }
 537         }
 538         return p;
 539 }
 540
 541 static void unmap_library(struct dso *dso)
 542 {
 543         if (dso->loadmap) {
 544                 size_t i;
 545                 for (i=0; i<dso->loadmap->nsegs; i++) {
 546                         if (!dso->loadmap->segs[i].p_memsz)
 547                                 continue;
 548                         munmap((void *)dso->loadmap->segs[i].addr,
 549                                 dso->loadmap->segs[i].p_memsz);
 550                 }
 551                 free(dso->loadmap);
 552         } else if (dso->map && dso->map_len) {
 553                 munmap(dso->map, dso->map_len);
 554         }
 555 }
 556
 557 static void *map_library(int fd, struct dso *dso)
 558 {
 559         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 560         void *allocated_buf=0;
 561         size_t phsize;
 562         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 563         size_t this_min, this_max;
 564         size_t nsegs = 0;
 565         off_t off_start;
 566         Ehdr *eh;
 567         Phdr *ph, *ph0;
 568         unsigned prot;
 569         unsigned char *map=MAP_FAILED, *base;
 570         size_t dyn=0;
 571         size_t tls_image=0;
 572         size_t i;
 573
 574         ssize_t l = read(fd, buf, sizeof buf);
 575         eh = buf;
 576         if (l<0) return 0;
 577         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 578                 goto noexec;
 579         phsize = eh->e_phentsize * eh->e_phnum;
 580         if (phsize > sizeof buf - sizeof *eh) {
 581                 allocated_buf = malloc(phsize);
 582                 if (!allocated_buf) return 0;
 583                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 584                 if (l < 0) goto error;
 585                 if (l != phsize) goto noexec;
 586                 ph = ph0 = allocated_buf;
 587         } else if (eh->e_phoff + phsize > l) {
 588                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 589                 if (l < 0) goto error;
 590                 if (l != phsize) goto noexec;
 591                 ph = ph0 = (void *)(buf + 1);
 592         } else {
 593                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 594         }
 595         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 596                 if (ph->p_type == PT_DYNAMIC) {
 597                         dyn = ph->p_vaddr;
 598                 } else if (ph->p_type == PT_TLS) {
 599                         tls_image = ph->p_vaddr;
 600                         dso->tls.align = ph->p_align;
 601                         dso->tls.len = ph->p_filesz;
 602                         dso->tls.size = ph->p_memsz;
 603                 } else if (ph->p_type == PT_GNU_RELRO) {
 604                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 605                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 606                 }
 607                 if (ph->p_type != PT_LOAD) continue;
 608                 nsegs++;
 609                 if (ph->p_vaddr < addr_min) {
 610                         addr_min = ph->p_vaddr;
 611                         off_start = ph->p_offset;
 612                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 613                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 614                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 615                 }
 616                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 617                         addr_max = ph->p_vaddr+ph->p_memsz;
 618                 }
 619         }
 620         if (!dyn) goto noexec;
 621         if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
 622                 dso->loadmap = calloc(1, sizeof *dso->loadmap
 623                         + nsegs * sizeof *dso->loadmap->segs);
 624                 if (!dso->loadmap) goto error;
 625                 dso->loadmap->nsegs = nsegs;
 626                 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
 627                         if (ph->p_type != PT_LOAD) continue;
 628                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 629                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 630                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 631                         map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
 632                                 prot, MAP_PRIVATE,
 633                                 fd, ph->p_offset & -PAGE_SIZE);
 634                         if (map == MAP_FAILED) {
 635                                 unmap_library(dso);
 636                                 goto error;
 637                         }
 638                         dso->loadmap->segs[i].addr = (size_t)map +
 639                                 (ph->p_vaddr & PAGE_SIZE-1);
 640                         dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
 641                         dso->loadmap->segs[i].p_memsz = ph->p_memsz;
 642                         i++;
 643                         if (prot & PROT_WRITE) {
 644                                 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
 645                                         + ph->p_filesz;
 646                                 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
 647                                 size_t pgend = brk + ph->p_memsz - ph->p_filesz
 648                                         + PAGE_SIZE-1 & -PAGE_SIZE;
 649                                 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
 650                                         pgend-pgbrk, prot,
 651                                         MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
 652                                         -1, off_start) == MAP_FAILED)
 653                                         goto error;
 654                                 memset(map + brk, 0, pgbrk-brk);
 655                         }
 656                 }
 657                 map = (void *)dso->loadmap->segs[0].addr;
 658                 map_len = 0;
 659                 goto done_mapping;
 660         }
 661         addr_max += PAGE_SIZE-1;
 662         addr_max &= -PAGE_SIZE;
 663         addr_min &= -PAGE_SIZE;
 664         off_start &= -PAGE_SIZE;
 665         map_len = addr_max - addr_min + off_start;
 666         /* The first time, we map too much, possibly even more than
 667          * the length of the file. This is okay because we will not
 668          * use the invalid part; we just need to reserve the right
 669          * amount of virtual address space to map over later. */
 670         map = DL_NOMMU_SUPPORT
 671                 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
 672                         MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
 673                 : mmap((void *)addr_min, map_len, prot,
 674                         MAP_PRIVATE, fd, off_start);
 675         if (map==MAP_FAILED) goto error;
 676         dso->map = map;
 677         dso->map_len = map_len;
 678         /* If the loaded file is not relocatable and the requested address is
 679          * not available, then the load operation must fail. */
 680         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 681                 errno = EBUSY;
 682                 goto error;
 683         }
 684         base = map - addr_min;
 685         dso->phdr = 0;
 686         dso->phnum = 0;
 687         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 688                 if (ph->p_type != PT_LOAD) continue;
 689                 /* Check if the programs headers are in this load segment, and
 690                  * if so, record the address for use by dl_iterate_phdr. */
 691                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 692                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 693                         dso->phdr = (void *)(base + ph->p_vaddr
 694                                 + (eh->e_phoff-ph->p_offset));
 695                         dso->phnum = eh->e_phnum;
 696                         dso->phentsize = eh->e_phentsize;
 697                 }
 698                 /* Reuse the existing mapping for the lowest-address LOAD */
 699                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min && !DL_NOMMU_SUPPORT)
 700                         continue;
 701                 this_min = ph->p_vaddr & -PAGE_SIZE;
 702                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 703                 off_start = ph->p_offset & -PAGE_SIZE;
 704                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 705                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 706                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 707                 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 708                         goto error;
 709                 if (ph->p_memsz > ph->p_filesz) {
 710                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 711                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 712                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 713                         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)
 714                                 goto error;
 715                 }
 716         }
 717         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 718                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 719                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
 720                             && errno != ENOSYS)
 721                                 goto error;
 722                         break;
 723                 }
 724 done_mapping:
 725         dso->base = base;
 726         dso->dynv = laddr(dso, dyn);
 727         if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
 728         free(allocated_buf);
 729         return map;
 730 noexec:
 731         errno = ENOEXEC;
 732 error:
 733         if (map!=MAP_FAILED) unmap_library(dso);
 734         free(allocated_buf);
 735         return 0;
 736 }
 737
 738 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 739 {
 740         size_t l;
 741         int fd;
 742         for (;;) {
 743                 s += strspn(s, ":\n");
 744                 l = strcspn(s, ":\n");
 745                 if (l-1 >= INT_MAX) return -1;
 746                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
 747                         if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 748                         switch (errno) {
 749                         case ENOENT:
 750                         case ENOTDIR:
 751                         case EACCES:
 752                         case ENAMETOOLONG:
 753                                 break;
 754                         default:
 755                                 /* Any negative value but -1 will inhibit
 756                                  * futher path search. */
 757                                 return -2;
 758                         }
 759                 }
 760                 s += l;
 761         }
 762 }
 763
 764 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 765 {
 766         size_t n, l;
 767         const char *s, *t, *origin;
 768         char *d;
 769         if (p->rpath || !p->rpath_orig) return 0;
 770         if (!strchr(p->rpath_orig, '$')) {
 771                 p->rpath = p->rpath_orig;
 772                 return 0;
 773         }
 774         n = 0;
 775         s = p->rpath_orig;
 776         while ((t=strchr(s, '$'))) {
 777                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 778                         return 0;
 779                 s = t+1;
 780                 n++;
 781         }
 782         if (n > SSIZE_MAX/PATH_MAX) return 0;
 783
 784         if (p->kernel_mapped) {
 785                 /* $ORIGIN searches cannot be performed for the main program
 786                  * when it is suid/sgid/AT_SECURE. This is because the
 787                  * pathname is under the control of the caller of execve.
 788                  * For libraries, however, $ORIGIN can be processed safely
 789                  * since the library's pathname came from a trusted source
 790                  * (either system paths or a call to dlopen). */
 791                 if (libc.secure)
 792                         return 0;
 793                 l = readlink("/proc/self/exe", buf, buf_size);
 794                 if (l == -1) switch (errno) {
 795                 case ENOENT:
 796                 case ENOTDIR:
 797                 case EACCES:
 798                         break;
 799                 default:
 800                         return -1;
 801                 }
 802                 if (l >= buf_size)
 803                         return 0;
 804                 buf[l] = 0;
 805                 origin = buf;
 806         } else {
 807                 origin = p->name;
 808         }
 809         t = strrchr(origin, '/');
 810         if (t) {
 811                 l = t-origin;
 812         } else {
 813                 /* Normally p->name will always be an absolute or relative
 814                  * pathname containing at least one '/' character, but in the
 815                  * case where ldso was invoked as a command to execute a
 816                  * program in the working directory, app.name may not. Fix. */
 817                 origin = ".";
 818                 l = 1;
 819         }
 820         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 821         if (!p->rpath) return -1;
 822
 823         d = p->rpath;
 824         s = p->rpath_orig;
 825         while ((t=strchr(s, '$'))) {
 826                 memcpy(d, s, t-s);
 827                 d += t-s;
 828                 memcpy(d, origin, l);
 829                 d += l;
 830                 /* It was determined previously that the '$' is followed
 831                  * either by "ORIGIN" or "{ORIGIN}". */
 832                 s = t + 7 + 2*(t[1]=='{');
 833         }
 834         strcpy(d, s);
 835         return 0;
 836 }
 837
 838 static void decode_dyn(struct dso *p)
 839 {
 840         size_t dyn[DYN_CNT];
 841         decode_vec(p->dynv, dyn, DYN_CNT);
 842         p->syms = laddr(p, dyn[DT_SYMTAB]);
 843         p->strings = laddr(p, dyn[DT_STRTAB]);
 844         if (dyn[0]&(1<<DT_HASH))
 845                 p->hashtab = laddr(p, dyn[DT_HASH]);
 846         if (dyn[0]&(1<<DT_RPATH))
 847                 p->rpath_orig = p->strings + dyn[DT_RPATH];
 848         if (dyn[0]&(1<<DT_RUNPATH))
 849                 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
 850         if (dyn[0]&(1<<DT_PLTGOT))
 851                 p->got = laddr(p, dyn[DT_PLTGOT]);
 852         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 853                 p->ghashtab = laddr(p, *dyn);
 854         if (search_vec(p->dynv, dyn, DT_VERSYM))
 855                 p->versym = laddr(p, *dyn);
 856 }
 857
 858 static size_t count_syms(struct dso *p)
 859 {
 860         if (p->hashtab) return p->hashtab[1];
 861
 862         size_t nsym, i;
 863         uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
 864         uint32_t *hashval;
 865         for (i = nsym = 0; i < p->ghashtab[0]; i++) {
 866                 if (buckets[i] > nsym)
 867                         nsym = buckets[i];
 868         }
 869         if (nsym) {
 870                 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
 871                 do nsym++;
 872                 while (!(*hashval++ & 1));
 873         }
 874         return nsym;
 875 }
 876
 877 static void *dl_mmap(size_t n)
 878 {
 879         void *p;
 880         int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
 881 #ifdef SYS_mmap2
 882         p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
 883 #else
 884         p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
 885 #endif
 886         return p == MAP_FAILED ? 0 : p;
 887 }
 888
 889 static void makefuncdescs(struct dso *p)
 890 {
 891         static int self_done;
 892         size_t nsym = count_syms(p);
 893         size_t i, size = nsym * sizeof(*p->funcdescs);
 894
 895         if (!self_done) {
 896                 p->funcdescs = dl_mmap(size);
 897                 self_done = 1;
 898         } else {
 899                 p->funcdescs = malloc(size);
 900         }
 901         if (!p->funcdescs) {
 902                 if (!runtime) a_crash();
 903                 error("Error allocating function descriptors for %s", p->name);
 904                 longjmp(*rtld_fail, 1);
 905         }
 906         for (i=0; i<nsym; i++) {
 907                 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
 908                         p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
 909                         p->funcdescs[i].got = p->got;
 910                 } else {
 911                         p->funcdescs[i].addr = 0;
 912                         p->funcdescs[i].got = 0;
 913                 }
 914         }
 915 }
 916
 917 static struct dso *load_library(const char *name, struct dso *needed_by)
 918 {
 919         char buf[2*NAME_MAX+2];
 920         const char *pathname;
 921         unsigned char *map;
 922         struct dso *p, temp_dso = {0};
 923         int fd;
 924         struct stat st;
 925         size_t alloc_size;
 926         int n_th = 0;
 927         int is_self = 0;
 928
 929         if (!*name) {
 930                 errno = EINVAL;
 931                 return 0;
 932         }
 933
 934         /* Catch and block attempts to reload the implementation itself */
 935         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 936                 static const char reserved[] =
 937                         "c.pthread.rt.m.dl.util.xnet.";
 938                 const char *rp, *next;
 939                 for (rp=reserved; *rp; rp=next) {
 940                         next = strchr(rp, '.') + 1;
 941                         if (strncmp(name+3, rp, next-rp) == 0)
 942                                 break;
 943                 }
 944                 if (*rp) {
 945                         if (ldd_mode) {
 946                                 /* Track which names have been resolved
 947                                  * and only report each one once. */
 948                                 static unsigned reported;
 949                                 unsigned mask = 1U<<(rp-reserved);
 950                                 if (!(reported & mask)) {
 951                                         reported |= mask;
 952                                         dprintf(1, "\t%s => %s (%p)\n",
 953                                                 name, ldso.name,
 954                                                 ldso.base);
 955                                 }
 956                         }
 957                         is_self = 1;
 958                 }
 959         }
 960         if (!strcmp(name, ldso.name)) is_self = 1;
 961         if (is_self) {
 962                 if (!ldso.prev) {
 963                         tail->next = &ldso;
 964                         ldso.prev = tail;
 965                         tail = &ldso;
 966                 }
 967                 return &ldso;
 968         }
 969         if (strchr(name, '/')) {
 970                 pathname = name;
 971                 fd = open(name, O_RDONLY|O_CLOEXEC);
 972         } else {
 973                 /* Search for the name to see if it's already loaded */
 974                 for (p=head->next; p; p=p->next) {
 975                         if (p->shortname && !strcmp(p->shortname, name)) {
 976                                 return p;
 977                         }
 978                 }
 979                 if (strlen(name) > NAME_MAX) return 0;
 980                 fd = -1;
 981                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 982                 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
 983                         if (fixup_rpath(p, buf, sizeof buf) < 0)
 984                                 fd = -2; /* Inhibit further search. */
 985                         if (p->rpath)
 986                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 987                 }
 988                 if (fd == -1) {
 989                         if (!sys_path) {
 990                                 char *prefix = 0;
 991                                 size_t prefix_len;
 992                                 if (ldso.name[0]=='/') {
 993                                         char *s, *t, *z;
 994                                         for (s=t=z=ldso.name; *s; s++)
 995                                                 if (*s=='/') z=t, t=s;
 996                                         prefix_len = z-ldso.name;
 997                                         if (prefix_len < PATH_MAX)
 998                                                 prefix = ldso.name;
 999                                 }
1000                                 if (!prefix) {
1001                                         prefix = "";
1002                                         prefix_len = 0;
1003                                 }
1004                                 char etc_ldso_path[prefix_len + 1
1005                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1006                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1007                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1008                                         (int)prefix_len, prefix);
1009                                 FILE *f = fopen(etc_ldso_path, "rbe");
1010                                 if (f) {
1011                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1012                                                 free(sys_path);
1013                                                 sys_path = "";
1014                                         }
1015                                         fclose(f);
1016                                 } else if (errno != ENOENT) {
1017                                         sys_path = "";
1018                                 }
1019                         }
1020                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1021                         fd = path_open(name, sys_path, buf, sizeof buf);
1022                 }
1023                 pathname = buf;
1024         }
1025         if (fd < 0) return 0;
1026         if (fstat(fd, &st) < 0) {
1027                 close(fd);
1028                 return 0;
1029         }
1030         for (p=head->next; p; p=p->next) {
1031                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1032                         /* If this library was previously loaded with a
1033                          * pathname but a search found the same inode,
1034                          * setup its shortname so it can be found by name. */
1035                         if (!p->shortname && pathname != name)
1036                                 p->shortname = strrchr(p->name, '/')+1;
1037                         close(fd);
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         /* Past this point, if we haven't reached runtime yet, ldso has
1056          * committed either to use the mapped library or to abort execution.
1057          * Unmapping is not possible, so we can safely reclaim gaps. */
1058         if (!runtime) reclaim_gaps(&temp_dso);
1059
1060         /* Allocate storage for the new DSO. When there is TLS, this
1061          * storage must include a reservation for all pre-existing
1062          * threads to obtain copies of both the new TLS, and an
1063          * extended DTV capable of storing an additional slot for
1064          * the newly-loaded DSO. */
1065         alloc_size = sizeof *p + strlen(pathname) + 1;
1066         if (runtime && temp_dso.tls.image) {
1067                 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1068                         + sizeof(void *) * (tls_cnt+3);
1069                 n_th = libc.threads_minus_1 + 1;
1070                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1071                 else alloc_size += n_th * per_th;
1072         }
1073         p = calloc(1, alloc_size);
1074         if (!p) {
1075                 unmap_library(&temp_dso);
1076                 return 0;
1077         }
1078         memcpy(p, &temp_dso, sizeof temp_dso);
1079         p->dev = st.st_dev;
1080         p->ino = st.st_ino;
1081         p->needed_by = needed_by;
1082         p->name = p->buf;
1083         strcpy(p->name, pathname);
1084         /* Add a shortname only if name arg was not an explicit pathname. */
1085         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1086         if (p->tls.image) {
1087                 p->tls_id = ++tls_cnt;
1088                 tls_align = MAXP2(tls_align, p->tls.align);
1089 #ifdef TLS_ABOVE_TP
1090                 p->tls.offset = tls_offset + ( (tls_align-1) &
1091                         -(tls_offset + (uintptr_t)p->tls.image) );
1092                 tls_offset += p->tls.size;
1093 #else
1094                 tls_offset += p->tls.size + p->tls.align - 1;
1095                 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1096                         & (p->tls.align-1);
1097                 p->tls.offset = tls_offset;
1098 #endif
1099                 p->new_dtv = (void *)(-sizeof(size_t) &
1100                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1101                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1102                 if (tls_tail) tls_tail->next = &p->tls;
1103                 else libc.tls_head = &p->tls;
1104                 tls_tail = &p->tls;
1105         }
1106
1107         tail->next = p;
1108         p->prev = tail;
1109         tail = p;
1110
1111         if (DL_FDPIC) makefuncdescs(p);
1112
1113         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1114
1115         return p;
1116 }
1117
1118 static void load_deps(struct dso *p)
1119 {
1120         size_t i, ndeps=0;
1121         struct dso ***deps = &p->deps, **tmp, *dep;
1122         for (; p; p=p->next) {
1123                 for (i=0; p->dynv[i]; i+=2) {
1124                         if (p->dynv[i] != DT_NEEDED) continue;
1125                         dep = load_library(p->strings + p->dynv[i+1], p);
1126                         if (!dep) {
1127                                 error("Error loading shared library %s: %m (needed by %s)",
1128                                         p->strings + p->dynv[i+1], p->name);
1129                                 if (runtime) longjmp(*rtld_fail, 1);
1130                                 continue;
1131                         }
1132                         if (runtime) {
1133                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1134                                 if (!tmp) longjmp(*rtld_fail, 1);
1135                                 tmp[ndeps++] = dep;
1136                                 tmp[ndeps] = 0;
1137                                 *deps = tmp;
1138                         }
1139                 }
1140         }
1141         if (!*deps) *deps = (struct dso **)&nodeps_dummy;
1142 }
1143
1144 static void load_preload(char *s)
1145 {
1146         int tmp;
1147         char *z;
1148         for (z=s; *z; s=z) {
1149                 for (   ; *s && (isspace(*s) || *s==':'); s++);
1150                 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1151                 tmp = *z;
1152                 *z = 0;
1153                 load_library(s, 0);
1154                 *z = tmp;
1155         }
1156 }
1157
1158 static void add_syms(struct dso *p)
1159 {
1160         if (!p->syms_next && syms_tail != p) {
1161                 syms_tail->syms_next = p;
1162                 syms_tail = p;
1163         }
1164 }
1165
1166 static void revert_syms(struct dso *old_tail)
1167 {
1168         struct dso *p, *next;
1169         /* Chop off the tail of the list of dsos that participate in
1170          * the global symbol table, reverting them to RTLD_LOCAL. */
1171         for (p=old_tail; p; p=next) {
1172                 next = p->syms_next;
1173                 p->syms_next = 0;
1174         }
1175         syms_tail = old_tail;
1176 }
1177
1178 static void do_mips_relocs(struct dso *p, size_t *got)
1179 {
1180         size_t i, j, rel[2];
1181         unsigned char *base = p->base;
1182         i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1183         if (p==&ldso) {
1184                 got += i;
1185         } else {
1186                 while (i--) *got++ += (size_t)base;
1187         }
1188         j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1189         i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1190         Sym *sym = p->syms + j;
1191         rel[0] = (unsigned char *)got - base;
1192         for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1193                 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1194                 do_relocs(p, rel, sizeof rel, 2);
1195         }
1196 }
1197
1198 static void reloc_all(struct dso *p)
1199 {
1200         size_t dyn[DYN_CNT];
1201         for (; p; p=p->next) {
1202                 if (p->relocated) continue;
1203                 decode_vec(p->dynv, dyn, DYN_CNT);
1204                 if (NEED_MIPS_GOT_RELOCS)
1205                         do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1206                 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1207                         2+(dyn[DT_PLTREL]==DT_RELA));
1208                 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1209                 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1210
1211                 if (head != &ldso && p->relro_start != p->relro_end &&
1212                     mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1213                     && errno != ENOSYS) {
1214                         error("Error relocating %s: RELRO protection failed: %m",
1215                                 p->name);
1216                         if (runtime) longjmp(*rtld_fail, 1);
1217                 }
1218
1219                 p->relocated = 1;
1220         }
1221 }
1222
1223 static void kernel_mapped_dso(struct dso *p)
1224 {
1225         size_t min_addr = -1, max_addr = 0, cnt;
1226         Phdr *ph = p->phdr;
1227         for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1228                 if (ph->p_type == PT_DYNAMIC) {
1229                         p->dynv = laddr(p, ph->p_vaddr);
1230                 } else if (ph->p_type == PT_GNU_RELRO) {
1231                         p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1232                         p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1233                 }
1234                 if (ph->p_type != PT_LOAD) continue;
1235                 if (ph->p_vaddr < min_addr)
1236                         min_addr = ph->p_vaddr;
1237                 if (ph->p_vaddr+ph->p_memsz > max_addr)
1238                         max_addr = ph->p_vaddr+ph->p_memsz;
1239         }
1240         min_addr &= -PAGE_SIZE;
1241         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1242         p->map = p->base + min_addr;
1243         p->map_len = max_addr - min_addr;
1244         p->kernel_mapped = 1;
1245 }
1246
1247 void __libc_exit_fini()
1248 {
1249         struct dso *p;
1250         size_t dyn[DYN_CNT];
1251         for (p=fini_head; p; p=p->fini_next) {
1252                 if (!p->constructed) continue;
1253                 decode_vec(p->dynv, dyn, DYN_CNT);
1254                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1255                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1256                         size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1257                         while (n--) ((void (*)(void))*--fn)();
1258                 }
1259 #ifndef NO_LEGACY_INITFINI
1260                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1261                         fpaddr(p, dyn[DT_FINI])();
1262 #endif
1263         }
1264 }
1265
1266 static void do_init_fini(struct dso *p)
1267 {
1268         size_t dyn[DYN_CNT];
1269         int need_locking = libc.threads_minus_1;
1270         /* Allow recursive calls that arise when a library calls
1271          * dlopen from one of its constructors, but block any
1272          * other threads until all ctors have finished. */
1273         if (need_locking) pthread_mutex_lock(&init_fini_lock);
1274         for (; p; p=p->prev) {
1275                 if (p->constructed) continue;
1276                 p->constructed = 1;
1277                 decode_vec(p->dynv, dyn, DYN_CNT);
1278                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1279                         p->fini_next = fini_head;
1280                         fini_head = p;
1281                 }
1282 #ifndef NO_LEGACY_INITFINI
1283                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1284                         fpaddr(p, dyn[DT_INIT])();
1285 #endif
1286                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1287                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1288                         size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1289                         while (n--) ((void (*)(void))*fn++)();
1290                 }
1291                 if (!need_locking && libc.threads_minus_1) {
1292                         need_locking = 1;
1293                         pthread_mutex_lock(&init_fini_lock);
1294                 }
1295         }
1296         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1297 }
1298
1299 void __libc_start_init(void)
1300 {
1301         do_init_fini(tail);
1302 }
1303
1304 static void dl_debug_state(void)
1305 {
1306 }
1307
1308 weak_alias(dl_debug_state, _dl_debug_state);
1309
1310 void __init_tls(size_t *auxv)
1311 {
1312 }
1313
1314 __attribute__((__visibility__("hidden")))
1315 void *__tls_get_new(tls_mod_off_t *v)
1316 {
1317         pthread_t self = __pthread_self();
1318
1319         /* Block signals to make accessing new TLS async-signal-safe */
1320         sigset_t set;
1321         __block_all_sigs(&set);
1322         if (v[0]<=(size_t)self->dtv[0]) {
1323                 __restore_sigs(&set);
1324                 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1325         }
1326
1327         /* This is safe without any locks held because, if the caller
1328          * is able to request the Nth entry of the DTV, the DSO list
1329          * must be valid at least that far out and it was synchronized
1330          * at program startup or by an already-completed call to dlopen. */
1331         struct dso *p;
1332         for (p=head; p->tls_id != v[0]; p=p->next);
1333
1334         /* Get new DTV space from new DSO if needed */
1335         if (v[0] > (size_t)self->dtv[0]) {
1336                 void **newdtv = p->new_dtv +
1337                         (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
1338                 memcpy(newdtv, self->dtv,
1339                         ((size_t)self->dtv[0]+1) * sizeof(void *));
1340                 newdtv[0] = (void *)v[0];
1341                 self->dtv = self->dtv_copy = newdtv;
1342         }
1343
1344         /* Get new TLS memory from all new DSOs up to the requested one */
1345         unsigned char *mem;
1346         for (p=head; ; p=p->next) {
1347                 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1348                 mem = p->new_tls + (p->tls.size + p->tls.align)
1349                         * a_fetch_add(&p->new_tls_idx,1);
1350                 mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1351                         & (p->tls.align-1);
1352                 self->dtv[p->tls_id] = mem;
1353                 memcpy(mem, p->tls.image, p->tls.len);
1354                 if (p->tls_id == v[0]) break;
1355         }
1356         __restore_sigs(&set);
1357         return mem + v[1] + DTP_OFFSET;
1358 }
1359
1360 static void update_tls_size()
1361 {
1362         libc.tls_cnt = tls_cnt;
1363         libc.tls_align = tls_align;
1364         libc.tls_size = ALIGN(
1365                 (1+tls_cnt) * sizeof(void *) +
1366                 tls_offset +
1367                 sizeof(struct pthread) +
1368                 tls_align * 2,
1369         tls_align);
1370 }
1371
1372 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1373  * following stage 2 and stage 3 functions via primitive symbolic lookup
1374  * since it does not have access to their addresses to begin with. */
1375
1376 /* Stage 2 of the dynamic linker is called after relative relocations
1377  * have been processed. It can make function calls to static functions
1378  * and access string literals and static data, but cannot use extern
1379  * symbols. Its job is to perform symbolic relocations on the dynamic
1380  * linker itself, but some of the relocations performed may need to be
1381  * replaced later due to copy relocations in the main program. */
1382
1383 __attribute__((__visibility__("hidden")))
1384 void __dls2(unsigned char *base, size_t *sp)
1385 {
1386         if (DL_FDPIC) {
1387                 void *p1 = (void *)sp[-2];
1388                 void *p2 = (void *)sp[-1];
1389                 if (!p1) {
1390                         size_t *auxv, aux[AUX_CNT];
1391                         for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1392                         decode_vec(auxv, aux, AUX_CNT);
1393                         if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1394                         else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1395                 }
1396                 app_loadmap = p2 ? p1 : 0;
1397                 ldso.loadmap = p2 ? p2 : p1;
1398                 ldso.base = laddr(&ldso, 0);
1399         } else {
1400                 ldso.base = base;
1401         }
1402         Ehdr *ehdr = (void *)ldso.base;
1403         ldso.name = ldso.shortname = "libc.so";
1404         ldso.phnum = ehdr->e_phnum;
1405         ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1406         ldso.phentsize = ehdr->e_phentsize;
1407         kernel_mapped_dso(&ldso);
1408         decode_dyn(&ldso);
1409
1410         if (DL_FDPIC) makefuncdescs(&ldso);
1411
1412         /* Prepare storage for to save clobbered REL addends so they
1413          * can be reused in stage 3. There should be very few. If
1414          * something goes wrong and there are a huge number, abort
1415          * instead of risking stack overflow. */
1416         size_t dyn[DYN_CNT];
1417         decode_vec(ldso.dynv, dyn, DYN_CNT);
1418         size_t *rel = laddr(&ldso, dyn[DT_REL]);
1419         size_t rel_size = dyn[DT_RELSZ];
1420         size_t symbolic_rel_cnt = 0;
1421         apply_addends_to = rel;
1422         for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1423                 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1424         if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1425         size_t addends[symbolic_rel_cnt+1];
1426         saved_addends = addends;
1427
1428         head = &ldso;
1429         reloc_all(&ldso);
1430
1431         ldso.relocated = 0;
1432
1433         /* Call dynamic linker stage-3, __dls3, looking it up
1434          * symbolically as a barrier against moving the address
1435          * load across the above relocation processing. */
1436         struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1437         if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1438         else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1439 }
1440
1441 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1442  * fully functional. Its job is to load (if not already loaded) and
1443  * process dependencies and relocations for the main application and
1444  * transfer control to its entry point. */
1445
1446 _Noreturn void __dls3(size_t *sp)
1447 {
1448         static struct dso app, vdso;
1449         size_t aux[AUX_CNT], *auxv;
1450         size_t i;
1451         char *env_preload=0;
1452         char *replace_argv0=0;
1453         size_t vdso_base;
1454         int argc = *sp;
1455         char **argv = (void *)(sp+1);
1456         char **argv_orig = argv;
1457         char **envp = argv+argc+1;
1458
1459         /* Find aux vector just past environ[] and use it to initialize
1460          * global data that may be needed before we can make syscalls. */
1461         __environ = envp;
1462         for (i=argc+1; argv[i]; i++);
1463         libc.auxv = auxv = (void *)(argv+i+1);
1464         decode_vec(auxv, aux, AUX_CNT);
1465         __hwcap = aux[AT_HWCAP];
1466         libc.page_size = aux[AT_PAGESZ];
1467         libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1468                 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1469
1470         /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1471          * use during dynamic linking. If possible it will also serve as the
1472          * thread pointer at runtime. */
1473         libc.tls_size = sizeof builtin_tls;
1474         libc.tls_align = tls_align;
1475         if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1476                 a_crash();
1477         }
1478
1479         /* Only trust user/env if kernel says we're not suid/sgid */
1480         if (!libc.secure) {
1481                 env_path = getenv("LD_LIBRARY_PATH");
1482                 env_preload = getenv("LD_PRELOAD");
1483         }
1484
1485         /* If the main program was already loaded by the kernel,
1486          * AT_PHDR will point to some location other than the dynamic
1487          * linker's program headers. */
1488         if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1489                 size_t interp_off = 0;
1490                 size_t tls_image = 0;
1491                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1492                 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1493                 app.phnum = aux[AT_PHNUM];
1494                 app.phentsize = aux[AT_PHENT];
1495                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1496                         if (phdr->p_type == PT_PHDR)
1497                                 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1498                         else if (phdr->p_type == PT_INTERP)
1499                                 interp_off = (size_t)phdr->p_vaddr;
1500                         else if (phdr->p_type == PT_TLS) {
1501                                 tls_image = phdr->p_vaddr;
1502                                 app.tls.len = phdr->p_filesz;
1503                                 app.tls.size = phdr->p_memsz;
1504                                 app.tls.align = phdr->p_align;
1505                         }
1506                 }
1507                 if (DL_FDPIC) app.loadmap = app_loadmap;
1508                 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1509                 if (interp_off) ldso.name = laddr(&app, interp_off);
1510                 if ((aux[0] & (1UL<<AT_EXECFN))
1511                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1512                         app.name = (char *)aux[AT_EXECFN];
1513                 else
1514                         app.name = argv[0];
1515                 kernel_mapped_dso(&app);
1516         } else {
1517                 int fd;
1518                 char *ldname = argv[0];
1519                 size_t l = strlen(ldname);
1520                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1521                 argv++;
1522                 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1523                         char *opt = argv[0]+2;
1524                         *argv++ = (void *)-1;
1525                         if (!*opt) {
1526                                 break;
1527                         } else if (!memcmp(opt, "list", 5)) {
1528                                 ldd_mode = 1;
1529                         } else if (!memcmp(opt, "library-path", 12)) {
1530                                 if (opt[12]=='=') env_path = opt+13;
1531                                 else if (opt[12]) *argv = 0;
1532                                 else if (*argv) env_path = *argv++;
1533                         } else if (!memcmp(opt, "preload", 7)) {
1534                                 if (opt[7]=='=') env_preload = opt+8;
1535                                 else if (opt[7]) *argv = 0;
1536                                 else if (*argv) env_preload = *argv++;
1537                         } else if (!memcmp(opt, "argv0", 5)) {
1538                                 if (opt[5]=='=') replace_argv0 = opt+6;
1539                                 else if (opt[5]) *argv = 0;
1540                                 else if (*argv) replace_argv0 = *argv++;
1541                         } else {
1542                                 argv[0] = 0;
1543                         }
1544                 }
1545                 argv[-1] = (void *)(argc - (argv-argv_orig));
1546                 if (!argv[0]) {
1547                         dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1548                                 "Version %s\n"
1549                                 "Dynamic Program Loader\n"
1550                                 "Usage: %s [options] [--] pathname%s\n",
1551                                 __libc_get_version(), ldname,
1552                                 ldd_mode ? "" : " [args]");
1553                         _exit(1);
1554                 }
1555                 fd = open(argv[0], O_RDONLY);
1556                 if (fd < 0) {
1557                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1558                         _exit(1);
1559                 }
1560                 Ehdr *ehdr = (void *)map_library(fd, &app);
1561                 if (!ehdr) {
1562                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1563                         _exit(1);
1564                 }
1565                 close(fd);
1566                 ldso.name = ldname;
1567                 app.name = argv[0];
1568                 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1569                 /* Find the name that would have been used for the dynamic
1570                  * linker had ldd not taken its place. */
1571                 if (ldd_mode) {
1572                         for (i=0; i<app.phnum; i++) {
1573                                 if (app.phdr[i].p_type == PT_INTERP)
1574                                         ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1575                         }
1576                         dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1577                 }
1578         }
1579         if (app.tls.size) {
1580                 libc.tls_head = tls_tail = &app.tls;
1581                 app.tls_id = tls_cnt = 1;
1582 #ifdef TLS_ABOVE_TP
1583                 app.tls.offset = 0;
1584                 tls_offset = app.tls.size
1585                         + ( -((uintptr_t)app.tls.image + app.tls.size)
1586                         & (app.tls.align-1) );
1587 #else
1588                 tls_offset = app.tls.offset = app.tls.size
1589                         + ( -((uintptr_t)app.tls.image + app.tls.size)
1590                         & (app.tls.align-1) );
1591 #endif
1592                 tls_align = MAXP2(tls_align, app.tls.align);
1593         }
1594         decode_dyn(&app);
1595         if (DL_FDPIC) {
1596                 makefuncdescs(&app);
1597                 if (!app.loadmap) {
1598                         app.loadmap = (void *)&app_dummy_loadmap;
1599                         app.loadmap->nsegs = 1;
1600                         app.loadmap->segs[0].addr = (size_t)app.map;
1601                         app.loadmap->segs[0].p_vaddr = (size_t)app.map
1602                                 - (size_t)app.base;
1603                         app.loadmap->segs[0].p_memsz = app.map_len;
1604                 }
1605                 argv[-3] = (void *)app.loadmap;
1606         }
1607
1608         /* Initial dso chain consists only of the app. */
1609         head = tail = syms_tail = &app;
1610
1611         /* Donate unused parts of app and library mapping to malloc */
1612         reclaim_gaps(&app);
1613         reclaim_gaps(&ldso);
1614
1615         /* Load preload/needed libraries, add symbols to global namespace. */
1616         if (env_preload) load_preload(env_preload);
1617         load_deps(&app);
1618         for (struct dso *p=head; p; p=p->next)
1619                 add_syms(p);
1620
1621         /* Attach to vdso, if provided by the kernel, last so that it does
1622          * not become part of the global namespace.  */
1623         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1624                 Ehdr *ehdr = (void *)vdso_base;
1625                 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1626                 vdso.phnum = ehdr->e_phnum;
1627                 vdso.phentsize = ehdr->e_phentsize;
1628                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1629                         if (phdr->p_type == PT_DYNAMIC)
1630                                 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1631                         if (phdr->p_type == PT_LOAD)
1632                                 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1633                 }
1634                 vdso.name = "";
1635                 vdso.shortname = "linux-gate.so.1";
1636                 vdso.relocated = 1;
1637                 decode_dyn(&vdso);
1638                 vdso.prev = tail;
1639                 tail->next = &vdso;
1640                 tail = &vdso;
1641         }
1642
1643         for (i=0; app.dynv[i]; i+=2) {
1644                 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1645                         app.dynv[i+1] = (size_t)&debug;
1646                 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1647                         size_t *ptr = (size_t *) app.dynv[i+1];
1648                         *ptr = (size_t)&debug;
1649                 }
1650         }
1651
1652         /* The main program must be relocated LAST since it may contin
1653          * copy relocations which depend on libraries' relocations. */
1654         reloc_all(app.next);
1655         reloc_all(&app);
1656
1657         update_tls_size();
1658         if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1659                 void *initial_tls = calloc(libc.tls_size, 1);
1660                 if (!initial_tls) {
1661                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1662                                 argv[0], libc.tls_size);
1663                         _exit(127);
1664                 }
1665                 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1666                         a_crash();
1667                 }
1668         } else {
1669                 size_t tmp_tls_size = libc.tls_size;
1670                 pthread_t self = __pthread_self();
1671                 /* Temporarily set the tls size to the full size of
1672                  * builtin_tls so that __copy_tls will use the same layout
1673                  * as it did for before. Then check, just to be safe. */
1674                 libc.tls_size = sizeof builtin_tls;
1675                 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1676                 libc.tls_size = tmp_tls_size;
1677         }
1678         static_tls_cnt = tls_cnt;
1679
1680         if (ldso_fail) _exit(127);
1681         if (ldd_mode) _exit(0);
1682
1683         /* Switch to runtime mode: any further failures in the dynamic
1684          * linker are a reportable failure rather than a fatal startup
1685          * error. */
1686         runtime = 1;
1687
1688         debug.ver = 1;
1689         debug.bp = dl_debug_state;
1690         debug.head = head;
1691         debug.base = ldso.base;
1692         debug.state = 0;
1693         _dl_debug_state();
1694
1695         if (replace_argv0) argv[0] = replace_argv0;
1696
1697         errno = 0;
1698
1699         CRTJMP((void *)aux[AT_ENTRY], argv-1);
1700         for(;;);
1701 }
1702
1703 static void prepare_lazy(struct dso *p)
1704 {
1705         size_t dyn[DYN_CNT], n, flags1=0;
1706         decode_vec(p->dynv, dyn, DYN_CNT);
1707         search_vec(p->dynv, &flags1, DT_FLAGS_1);
1708         if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1709                 return;
1710         n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1711         if (NEED_MIPS_GOT_RELOCS) {
1712                 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1713                 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1714                 n += i-j;
1715         }
1716         p->lazy = calloc(n, 3*sizeof(size_t));
1717         if (!p->lazy) {
1718                 error("Error preparing lazy relocation for %s: %m", p->name);
1719                 longjmp(*rtld_fail, 1);
1720         }
1721         p->lazy_next = lazy_head;
1722         lazy_head = p;
1723 }
1724
1725 void *dlopen(const char *file, int mode)
1726 {
1727         struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1728         struct tls_module *orig_tls_tail;
1729         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1730         size_t i;
1731         int cs;
1732         jmp_buf jb;
1733
1734         if (!file) return head;
1735
1736         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1737         pthread_rwlock_wrlock(&lock);
1738         __inhibit_ptc();
1739
1740         p = 0;
1741         orig_tls_tail = tls_tail;
1742         orig_tls_cnt = tls_cnt;
1743         orig_tls_offset = tls_offset;
1744         orig_tls_align = tls_align;
1745         orig_lazy_head = lazy_head;
1746         orig_syms_tail = syms_tail;
1747         orig_tail = tail;
1748         noload = mode & RTLD_NOLOAD;
1749
1750         rtld_fail = &jb;
1751         if (setjmp(*rtld_fail)) {
1752                 /* Clean up anything new that was (partially) loaded */
1753                 revert_syms(orig_syms_tail);
1754                 for (p=orig_tail->next; p; p=next) {
1755                         next = p->next;
1756                         while (p->td_index) {
1757                                 void *tmp = p->td_index->next;
1758                                 free(p->td_index);
1759                                 p->td_index = tmp;
1760                         }
1761                         free(p->funcdescs);
1762                         if (p->rpath != p->rpath_orig)
1763                                 free(p->rpath);
1764                         if (p->deps != &nodeps_dummy)
1765                                 free(p->deps);
1766                         unmap_library(p);
1767                         free(p);
1768                 }
1769                 if (!orig_tls_tail) libc.tls_head = 0;
1770                 tls_tail = orig_tls_tail;
1771                 if (tls_tail) tls_tail->next = 0;
1772                 tls_cnt = orig_tls_cnt;
1773                 tls_offset = orig_tls_offset;
1774                 tls_align = orig_tls_align;
1775                 lazy_head = orig_lazy_head;
1776                 tail = orig_tail;
1777                 tail->next = 0;
1778                 p = 0;
1779                 goto end;
1780         } else p = load_library(file, head);
1781
1782         if (!p) {
1783                 error(noload ?
1784                         "Library %s is not already loaded" :
1785                         "Error loading shared library %s: %m",
1786                         file);
1787                 goto end;
1788         }
1789
1790         /* First load handling */
1791         int first_load = !p->deps;
1792         if (first_load) {
1793                 load_deps(p);
1794                 if (!p->relocated && (mode & RTLD_LAZY)) {
1795                         prepare_lazy(p);
1796                         for (i=0; p->deps[i]; i++)
1797                                 if (!p->deps[i]->relocated)
1798                                         prepare_lazy(p->deps[i]);
1799                 }
1800         }
1801         if (first_load || (mode & RTLD_GLOBAL)) {
1802                 /* Make new symbols global, at least temporarily, so we can do
1803                  * relocations. If not RTLD_GLOBAL, this is reverted below. */
1804                 add_syms(p);
1805                 for (i=0; p->deps[i]; i++)
1806                         add_syms(p->deps[i]);
1807         }
1808         if (first_load) {
1809                 reloc_all(p);
1810         }
1811
1812         /* If RTLD_GLOBAL was not specified, undo any new additions
1813          * to the global symbol table. This is a nop if the library was
1814          * previously loaded and already global. */
1815         if (!(mode & RTLD_GLOBAL))
1816                 revert_syms(orig_syms_tail);
1817
1818         /* Processing of deferred lazy relocations must not happen until
1819          * the new libraries are committed; otherwise we could end up with
1820          * relocations resolved to symbol definitions that get removed. */
1821         redo_lazy_relocs();
1822
1823         update_tls_size();
1824         _dl_debug_state();
1825         orig_tail = tail;
1826 end:
1827         __release_ptc();
1828         if (p) gencnt++;
1829         pthread_rwlock_unlock(&lock);
1830         if (p) do_init_fini(orig_tail);
1831         pthread_setcancelstate(cs, 0);
1832         return p;
1833 }
1834
1835 __attribute__((__visibility__("hidden")))
1836 int __dl_invalid_handle(void *h)
1837 {
1838         struct dso *p;
1839         for (p=head; p; p=p->next) if (h==p) return 0;
1840         error("Invalid library handle %p", (void *)h);
1841         return 1;
1842 }
1843
1844 static void *addr2dso(size_t a)
1845 {
1846         struct dso *p;
1847         size_t i;
1848         if (DL_FDPIC) for (p=head; p; p=p->next) {
1849                 i = count_syms(p);
1850                 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1851                         return p;
1852         }
1853         for (p=head; p; p=p->next) {
1854                 if (DL_FDPIC && p->loadmap) {
1855                         for (i=0; i<p->loadmap->nsegs; i++) {
1856                                 if (a-p->loadmap->segs[i].p_vaddr
1857                                     < p->loadmap->segs[i].p_memsz)
1858                                         return p;
1859                         }
1860                 } else {
1861                         if (a-(size_t)p->map < p->map_len)
1862                                 return p;
1863                 }
1864         }
1865         return 0;
1866 }
1867
1868 void *__tls_get_addr(tls_mod_off_t *);
1869
1870 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1871 {
1872         size_t i;
1873         uint32_t h = 0, gh = 0, *ght;
1874         Sym *sym;
1875         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1876                 if (p == RTLD_DEFAULT) {
1877                         p = head;
1878                 } else if (p == RTLD_NEXT) {
1879                         p = addr2dso((size_t)ra);
1880                         if (!p) p=head;
1881                         p = p->next;
1882                 }
1883                 struct symdef def = find_sym(p, s, 0);
1884                 if (!def.sym) goto failed;
1885                 if ((def.sym->st_info&0xf) == STT_TLS)
1886                         return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value});
1887                 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1888                         return def.dso->funcdescs + (def.sym - def.dso->syms);
1889                 return laddr(def.dso, def.sym->st_value);
1890         }
1891         if (__dl_invalid_handle(p))
1892                 return 0;
1893         if ((ght = p->ghashtab)) {
1894                 gh = gnu_hash(s);
1895                 sym = gnu_lookup(gh, ght, p, s);
1896         } else {
1897                 h = sysv_hash(s);
1898                 sym = sysv_lookup(s, h, p);
1899         }
1900         if (sym && (sym->st_info&0xf) == STT_TLS)
1901                 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value});
1902         if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1903                 return p->funcdescs + (sym - p->syms);
1904         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1905                 return laddr(p, sym->st_value);
1906         for (i=0; p->deps[i]; i++) {
1907                 if ((ght = p->deps[i]->ghashtab)) {
1908                         if (!gh) gh = gnu_hash(s);
1909                         sym = gnu_lookup(gh, ght, p->deps[i], s);
1910                 } else {
1911                         if (!h) h = sysv_hash(s);
1912                         sym = sysv_lookup(s, h, p->deps[i]);
1913                 }
1914                 if (sym && (sym->st_info&0xf) == STT_TLS)
1915                         return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value});
1916                 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1917                         return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1918                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1919                         return laddr(p->deps[i], sym->st_value);
1920         }
1921 failed:
1922         error("Symbol not found: %s", s);
1923         return 0;
1924 }
1925
1926 int dladdr(const void *addr, Dl_info *info)
1927 {
1928         struct dso *p;
1929         Sym *sym, *bestsym;
1930         uint32_t nsym;
1931         char *strings;
1932         void *best = 0;
1933
1934         pthread_rwlock_rdlock(&lock);
1935         p = addr2dso((size_t)addr);
1936         pthread_rwlock_unlock(&lock);
1937
1938         if (!p) return 0;
1939
1940         sym = p->syms;
1941         strings = p->strings;
1942         nsym = count_syms(p);
1943
1944         if (DL_FDPIC) {
1945                 size_t idx = ((size_t)addr-(size_t)p->funcdescs)
1946                         / sizeof(*p->funcdescs);
1947                 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1948                         best = p->funcdescs + idx;
1949                         bestsym = sym + idx;
1950                 }
1951         }
1952
1953         if (!best) for (; nsym; nsym--, sym++) {
1954                 if (sym->st_value
1955                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1956                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1957                         void *symaddr = laddr(p, sym->st_value);
1958                         if (symaddr > addr || symaddr < best)
1959                                 continue;
1960                         best = symaddr;
1961                         bestsym = sym;
1962                         if (addr == symaddr)
1963                                 break;
1964                 }
1965         }
1966
1967         if (!best) return 0;
1968
1969         if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
1970                 best = p->funcdescs + (bestsym - p->syms);
1971
1972         info->dli_fname = p->name;
1973         info->dli_fbase = p->map;
1974         info->dli_sname = strings + bestsym->st_name;
1975         info->dli_saddr = best;
1976
1977         return 1;
1978 }
1979
1980 __attribute__((__visibility__("hidden")))
1981 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1982 {
1983         void *res;
1984         pthread_rwlock_rdlock(&lock);
1985         res = do_dlsym(p, s, ra);
1986         pthread_rwlock_unlock(&lock);
1987         return res;
1988 }
1989
1990 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1991 {
1992         struct dso *current;
1993         struct dl_phdr_info info;
1994         int ret = 0;
1995         for(current = head; current;) {
1996                 info.dlpi_addr      = (uintptr_t)current->base;
1997                 info.dlpi_name      = current->name;
1998                 info.dlpi_phdr      = current->phdr;
1999                 info.dlpi_phnum     = current->phnum;
2000                 info.dlpi_adds      = gencnt;
2001                 info.dlpi_subs      = 0;
2002                 info.dlpi_tls_modid = current->tls_id;
2003                 info.dlpi_tls_data  = current->tls.image;
2004
2005                 ret = (callback)(&info, sizeof (info), data);
2006
2007                 if (ret != 0) break;
2008
2009                 pthread_rwlock_rdlock(&lock);
2010                 current = current->next;
2011                 pthread_rwlock_unlock(&lock);
2012         }
2013         return ret;
2014 }
2015
2016 __attribute__((__visibility__("hidden")))
2017 void __dl_vseterr(const char *, va_list);
2018
2019 static void error(const char *fmt, ...)
2020 {
2021         va_list ap;
2022         va_start(ap, fmt);
2023         if (!runtime) {
2024                 vdprintf(2, fmt, ap);
2025                 dprintf(2, "\n");
2026                 ldso_fail = 1;
2027                 va_end(ap);
2028                 return;
2029         }
2030         __dl_vseterr(fmt, ap);
2031         va_end(ap);
2032 }