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