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
  23 static int errflag;
  24 static char errbuf[128];
  25
  26 #ifdef SHARED
  27
  28 #if ULONG_MAX == 0xffffffff
  29 typedef Elf32_Ehdr Ehdr;
  30 typedef Elf32_Phdr Phdr;
  31 typedef Elf32_Sym Sym;
  32 #define R_TYPE(x) ((x)&255)
  33 #define R_SYM(x) ((x)>>8)
  34 #else
  35 typedef Elf64_Ehdr Ehdr;
  36 typedef Elf64_Phdr Phdr;
  37 typedef Elf64_Sym Sym;
  38 #define R_TYPE(x) ((x)&0xffffffff)
  39 #define R_SYM(x) ((x)>>32)
  40 #endif
  41
  42 #define MAXP2(a,b) (-(-(a)&-(b)))
  43 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  44
  45 struct debug {
  46         int ver;
  47         void *head;
  48         void (*bp)(void);
  49         int state;
  50         void *base;
  51 };
  52
  53 struct td_index {
  54         size_t args[2];
  55         struct td_index *next;
  56 };
  57
  58 struct dso {
  59         unsigned char *base;
  60         char *name;
  61         size_t *dynv;
  62         struct dso *next, *prev;
  63
  64         Phdr *phdr;
  65         int phnum;
  66         size_t phentsize;
  67         int refcnt;
  68         Sym *syms;
  69         uint32_t *hashtab;
  70         uint32_t *ghashtab;
  71         int16_t *versym;
  72         char *strings;
  73         unsigned char *map;
  74         size_t map_len;
  75         dev_t dev;
  76         ino_t ino;
  77         signed char global;
  78         char relocated;
  79         char constructed;
  80         char kernel_mapped;
  81         struct dso **deps, *needed_by;
  82         char *rpath_orig, *rpath;
  83         void *tls_image;
  84         size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
  85         size_t relro_start, relro_end;
  86         void **new_dtv;
  87         unsigned char *new_tls;
  88         volatile int new_dtv_idx, new_tls_idx;
  89         struct td_index *td_index;
  90         struct dso *fini_next;
  91         char *shortname;
  92         char buf[];
  93 };
  94
  95 struct symdef {
  96         Sym *sym;
  97         struct dso *dso;
  98 };
  99
 100 enum {
 101         REL_ERR,
 102         REL_SYMBOLIC,
 103         REL_GOT,
 104         REL_PLT,
 105         REL_RELATIVE,
 106         REL_OFFSET,
 107         REL_OFFSET32,
 108         REL_COPY,
 109         REL_SYM_OR_REL,
 110         REL_TLS, /* everything past here is TLS */
 111         REL_DTPMOD,
 112         REL_DTPOFF,
 113         REL_TPOFF,
 114         REL_TPOFF_NEG,
 115         REL_TLSDESC,
 116 };
 117
 118 #include "reloc.h"
 119
 120 int __init_tp(void *);
 121 void __init_libc(char **, char *);
 122
 123 const char *__libc_get_version(void);
 124
 125 static struct builtin_tls {
 126         char c;
 127         struct pthread pt;
 128         void *space[16];
 129 } builtin_tls[1];
 130 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
 131
 132 static struct dso *head, *tail, *ldso, *fini_head;
 133 static char *env_path, *sys_path;
 134 static unsigned long long gencnt;
 135 static int runtime;
 136 static int ldd_mode;
 137 static int ldso_fail;
 138 static int noload;
 139 static jmp_buf *rtld_fail;
 140 static pthread_rwlock_t lock;
 141 static struct debug debug;
 142 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
 143 static size_t static_tls_cnt;
 144 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 145
 146 struct debug *_dl_debug_addr = &debug;
 147
 148 #define AUX_CNT 38
 149 #define DYN_CNT 34
 150
 151 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 152 {
 153         memset(a, 0, cnt*sizeof(size_t));
 154         for (; v[0]; v+=2) if (v[0]<cnt) {
 155                 a[0] |= 1ULL<<v[0];
 156                 a[v[0]] = v[1];
 157         }
 158 }
 159
 160 static int search_vec(size_t *v, size_t *r, size_t key)
 161 {
 162         for (; v[0]!=key; v+=2)
 163                 if (!v[0]) return 0;
 164         *r = v[1];
 165         return 1;
 166 }
 167
 168 static void error(const char *fmt, ...)
 169 {
 170         va_list ap;
 171         va_start(ap, fmt);
 172         vsnprintf(errbuf, sizeof errbuf, fmt, ap);
 173         va_end(ap);
 174         if (runtime) longjmp(*rtld_fail, 1);
 175         dprintf(2, "%s\n", errbuf);
 176         ldso_fail = 1;
 177 }
 178
 179 static uint32_t sysv_hash(const char *s0)
 180 {
 181         const unsigned char *s = (void *)s0;
 182         uint_fast32_t h = 0;
 183         while (*s) {
 184                 h = 16*h + *s++;
 185                 h ^= h>>24 & 0xf0;
 186         }
 187         return h & 0xfffffff;
 188 }
 189
 190 static uint32_t gnu_hash(const char *s0)
 191 {
 192         const unsigned char *s = (void *)s0;
 193         uint_fast32_t h = 5381;
 194         for (; *s; s++)
 195                 h = h*33 + *s;
 196         return h;
 197 }
 198
 199 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 200 {
 201         size_t i;
 202         Sym *syms = dso->syms;
 203         uint32_t *hashtab = dso->hashtab;
 204         char *strings = dso->strings;
 205         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 206                 if ((!dso->versym || dso->versym[i] >= 0)
 207                     && (!strcmp(s, strings+syms[i].st_name)))
 208                         return syms+i;
 209         }
 210         return 0;
 211 }
 212
 213 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 214 {
 215         Sym *syms = dso->syms;
 216         char *strings = dso->strings;
 217         uint32_t *hashtab = dso->ghashtab;
 218         uint32_t nbuckets = hashtab[0];
 219         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 220         uint32_t h2;
 221         uint32_t *hashval;
 222         uint32_t i = buckets[h1 % nbuckets];
 223
 224         if (!i) return 0;
 225
 226         hashval = buckets + nbuckets + (i - hashtab[1]);
 227
 228         for (h1 |= 1; ; i++) {
 229                 h2 = *hashval++;
 230                 if ((!dso->versym || dso->versym[i] >= 0)
 231                     && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
 232                         return syms+i;
 233                 if (h2 & 1) break;
 234         }
 235
 236         return 0;
 237 }
 238
 239 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 240 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 241
 242 #ifndef ARCH_SYM_REJECT_UND
 243 #define ARCH_SYM_REJECT_UND(s) 0
 244 #endif
 245
 246 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 247 {
 248         uint32_t h = 0, gh = 0;
 249         struct symdef def = {0};
 250         for (; dso; dso=dso->next) {
 251                 Sym *sym;
 252                 if (!dso->global) continue;
 253                 if (dso->ghashtab) {
 254                         if (!gh) gh = gnu_hash(s);
 255                         sym = gnu_lookup(s, gh, dso);
 256                 } else {
 257                         if (!h) h = sysv_hash(s);
 258                         sym = sysv_lookup(s, h, dso);
 259                 }
 260                 if (!sym) continue;
 261                 if (!sym->st_shndx)
 262                         if (need_def || (sym->st_info&0xf) == STT_TLS
 263                             || ARCH_SYM_REJECT_UND(sym))
 264                                 continue;
 265                 if (!sym->st_value)
 266                         if ((sym->st_info&0xf) != STT_TLS)
 267                                 continue;
 268                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 269                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 270
 271                 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
 272                 def.sym = sym;
 273                 def.dso = dso;
 274                 if (sym->st_info>>4 == STB_GLOBAL) break;
 275         }
 276         return def;
 277 }
 278
 279 #define NO_INLINE_ADDEND (1<<REL_COPY | 1<<REL_GOT | 1<<REL_PLT)
 280
 281 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
 282
 283 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 284 {
 285         unsigned char *base = dso->base;
 286         Sym *syms = dso->syms;
 287         char *strings = dso->strings;
 288         Sym *sym;
 289         const char *name;
 290         void *ctx;
 291         int astype, type;
 292         int sym_index;
 293         struct symdef def;
 294         size_t *reloc_addr;
 295         size_t sym_val;
 296         size_t tls_val;
 297         size_t addend;
 298
 299         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 300                 astype = R_TYPE(rel[1]);
 301                 if (!astype) continue;
 302                 type = remap_rel(astype);
 303                 if (!type) {
 304                         error("Error relocating %s: unsupported relocation type %d",
 305                                 dso->name, astype);
 306                         continue;
 307                 }
 308                 sym_index = R_SYM(rel[1]);
 309                 reloc_addr = (void *)(base + rel[0]);
 310                 if (sym_index) {
 311                         sym = syms + sym_index;
 312                         name = strings + sym->st_name;
 313                         ctx = type==REL_COPY ? head->next : head;
 314                         def = find_sym(ctx, name, type==REL_PLT);
 315                         if (!def.sym && (sym->st_shndx != SHN_UNDEF
 316                             || sym->st_info>>4 != STB_WEAK)) {
 317                                 error("Error relocating %s: %s: symbol not found",
 318                                         dso->name, name);
 319                                 continue;
 320                         }
 321                 } else {
 322                         sym = 0;
 323                         def.sym = 0;
 324                         def.dso = dso;
 325                 }
 326
 327                 addend = stride>2 ? rel[2]
 328                         : (1<<type & NO_INLINE_ADDEND) ? 0
 329                         : *reloc_addr;
 330
 331                 sym_val = def.sym ? (size_t)def.dso->base+def.sym->st_value : 0;
 332                 tls_val = def.sym ? def.sym->st_value : 0;
 333
 334                 switch(type) {
 335                 case REL_OFFSET:
 336                         addend -= (size_t)reloc_addr;
 337                 case REL_SYMBOLIC:
 338                 case REL_GOT:
 339                 case REL_PLT:
 340                         *reloc_addr = sym_val + addend;
 341                         break;
 342                 case REL_RELATIVE:
 343                         *reloc_addr = (size_t)base + addend;
 344                         break;
 345                 case REL_SYM_OR_REL:
 346                         if (sym) *reloc_addr = sym_val + addend;
 347                         else *reloc_addr = (size_t)base + addend;
 348                         break;
 349                 case REL_COPY:
 350                         memcpy(reloc_addr, (void *)sym_val, sym->st_size);
 351                         break;
 352                 case REL_OFFSET32:
 353                         *(uint32_t *)reloc_addr = sym_val + addend
 354                                 - (size_t)reloc_addr;
 355                         break;
 356                 case REL_DTPMOD:
 357                         *reloc_addr = def.dso->tls_id;
 358                         break;
 359                 case REL_DTPOFF:
 360                         *reloc_addr = tls_val + addend;
 361                         break;
 362 #ifdef TLS_ABOVE_TP
 363                 case REL_TPOFF:
 364                         *reloc_addr = tls_val + def.dso->tls_offset + TPOFF_K + addend;
 365                         break;
 366 #else
 367                 case REL_TPOFF:
 368                         *reloc_addr = tls_val - def.dso->tls_offset + addend;
 369                         break;
 370                 case REL_TPOFF_NEG:
 371                         *reloc_addr = def.dso->tls_offset - tls_val + addend;
 372                         break;
 373 #endif
 374                 case REL_TLSDESC:
 375                         if (stride<3) addend = reloc_addr[1];
 376                         if (runtime && def.dso->tls_id >= static_tls_cnt) {
 377                                 struct td_index *new = malloc(sizeof *new);
 378                                 if (!new) error(
 379                                         "Error relocating %s: cannot allocate TLSDESC for %s",
 380                                         dso->name, sym ? name : "(local)" );
 381                                 new->next = dso->td_index;
 382                                 dso->td_index = new;
 383                                 new->args[0] = def.dso->tls_id;
 384                                 new->args[1] = tls_val + addend;
 385                                 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
 386                                 reloc_addr[1] = (size_t)new;
 387                         } else {
 388                                 reloc_addr[0] = (size_t)__tlsdesc_static;
 389 #ifdef TLS_ABOVE_TP
 390                                 reloc_addr[1] = tls_val + def.dso->tls_offset
 391                                         + TPOFF_K + addend;
 392 #else
 393                                 reloc_addr[1] = tls_val - def.dso->tls_offset
 394                                         + addend;
 395 #endif
 396                         }
 397                         break;
 398                 }
 399         }
 400 }
 401
 402 /* A huge hack: to make up for the wastefulness of shared libraries
 403  * needing at least a page of dirty memory even if they have no global
 404  * data, we reclaim the gaps at the beginning and end of writable maps
 405  * and "donate" them to the heap by setting up minimal malloc
 406  * structures and then freeing them. */
 407
 408 static void reclaim(struct dso *dso, size_t start, size_t end)
 409 {
 410         size_t *a, *z;
 411         if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
 412         if (end   >= dso->relro_start && end   < dso->relro_end) end = dso->relro_start;
 413         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 414         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 415         if (start>end || end-start < 4*sizeof(size_t)) return;
 416         a = (size_t *)(dso->base + start);
 417         z = (size_t *)(dso->base + end);
 418         a[-2] = 1;
 419         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 420         z[1] = 1;
 421         free(a);
 422 }
 423
 424 static void reclaim_gaps(struct dso *dso)
 425 {
 426         Phdr *ph = dso->phdr;
 427         size_t phcnt = dso->phnum;
 428
 429         for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
 430                 if (ph->p_type!=PT_LOAD) continue;
 431                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 432                 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 433                 reclaim(dso, ph->p_vaddr+ph->p_memsz,
 434                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 435         }
 436 }
 437
 438 static void *map_library(int fd, struct dso *dso)
 439 {
 440         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 441         void *allocated_buf=0;
 442         size_t phsize;
 443         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 444         size_t this_min, this_max;
 445         off_t off_start;
 446         Ehdr *eh;
 447         Phdr *ph, *ph0;
 448         unsigned prot;
 449         unsigned char *map=MAP_FAILED, *base;
 450         size_t dyn=0;
 451         size_t tls_image=0;
 452         size_t i;
 453
 454         ssize_t l = read(fd, buf, sizeof buf);
 455         eh = buf;
 456         if (l<0) return 0;
 457         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 458                 goto noexec;
 459         phsize = eh->e_phentsize * eh->e_phnum;
 460         if (phsize > sizeof buf - sizeof *eh) {
 461                 allocated_buf = malloc(phsize);
 462                 if (!allocated_buf) return 0;
 463                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 464                 if (l < 0) goto error;
 465                 if (l != phsize) goto noexec;
 466                 ph = ph0 = allocated_buf;
 467         } else if (eh->e_phoff + phsize > l) {
 468                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 469                 if (l < 0) goto error;
 470                 if (l != phsize) goto noexec;
 471                 ph = ph0 = (void *)(buf + 1);
 472         } else {
 473                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 474         }
 475         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 476                 if (ph->p_type == PT_DYNAMIC) {
 477                         dyn = ph->p_vaddr;
 478                 } else if (ph->p_type == PT_TLS) {
 479                         tls_image = ph->p_vaddr;
 480                         dso->tls_align = ph->p_align;
 481                         dso->tls_len = ph->p_filesz;
 482                         dso->tls_size = ph->p_memsz;
 483                 } else if (ph->p_type == PT_GNU_RELRO) {
 484                         dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
 485                         dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 486                 }
 487                 if (ph->p_type != PT_LOAD) continue;
 488                 if (ph->p_vaddr < addr_min) {
 489                         addr_min = ph->p_vaddr;
 490                         off_start = ph->p_offset;
 491                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 492                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 493                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 494                 }
 495                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 496                         addr_max = ph->p_vaddr+ph->p_memsz;
 497                 }
 498         }
 499         if (!dyn) goto noexec;
 500         addr_max += PAGE_SIZE-1;
 501         addr_max &= -PAGE_SIZE;
 502         addr_min &= -PAGE_SIZE;
 503         off_start &= -PAGE_SIZE;
 504         map_len = addr_max - addr_min + off_start;
 505         /* The first time, we map too much, possibly even more than
 506          * the length of the file. This is okay because we will not
 507          * use the invalid part; we just need to reserve the right
 508          * amount of virtual address space to map over later. */
 509         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 510         if (map==MAP_FAILED) goto error;
 511         /* If the loaded file is not relocatable and the requested address is
 512          * not available, then the load operation must fail. */
 513         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 514                 errno = EBUSY;
 515                 goto error;
 516         }
 517         base = map - addr_min;
 518         dso->phdr = 0;
 519         dso->phnum = 0;
 520         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 521                 if (ph->p_type != PT_LOAD) continue;
 522                 /* Check if the programs headers are in this load segment, and
 523                  * if so, record the address for use by dl_iterate_phdr. */
 524                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 525                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 526                         dso->phdr = (void *)(base + ph->p_vaddr
 527                                 + (eh->e_phoff-ph->p_offset));
 528                         dso->phnum = eh->e_phnum;
 529                         dso->phentsize = eh->e_phentsize;
 530                 }
 531                 /* Reuse the existing mapping for the lowest-address LOAD */
 532                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 533                 this_min = ph->p_vaddr & -PAGE_SIZE;
 534                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 535                 off_start = ph->p_offset & -PAGE_SIZE;
 536                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 537                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 538                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 539                 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 540                         goto error;
 541                 if (ph->p_memsz > ph->p_filesz) {
 542                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 543                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 544                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 545                         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)
 546                                 goto error;
 547                 }
 548         }
 549         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 550                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 551                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
 552                                 goto error;
 553                         break;
 554                 }
 555         dso->map = map;
 556         dso->map_len = map_len;
 557         dso->base = base;
 558         dso->dynv = (void *)(base+dyn);
 559         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 560         if (!runtime) reclaim_gaps(dso);
 561         free(allocated_buf);
 562         return map;
 563 noexec:
 564         errno = ENOEXEC;
 565 error:
 566         if (map!=MAP_FAILED) munmap(map, map_len);
 567         free(allocated_buf);
 568         return 0;
 569 }
 570
 571 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 572 {
 573         size_t l;
 574         int fd;
 575         for (;;) {
 576                 s += strspn(s, ":\n");
 577                 l = strcspn(s, ":\n");
 578                 if (l-1 >= INT_MAX) return -1;
 579                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
 580                         if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 581                         switch (errno) {
 582                         case ENOENT:
 583                         case ENOTDIR:
 584                         case EACCES:
 585                         case ENAMETOOLONG:
 586                                 break;
 587                         default:
 588                                 /* Any negative value but -1 will inhibit
 589                                  * futher path search. */
 590                                 return -2;
 591                         }
 592                 }
 593                 s += l;
 594         }
 595 }
 596
 597 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 598 {
 599         size_t n, l;
 600         const char *s, *t, *origin;
 601         char *d;
 602         if (p->rpath || !p->rpath_orig) return 0;
 603         if (!strchr(p->rpath_orig, '$')) {
 604                 p->rpath = p->rpath_orig;
 605                 return 0;
 606         }
 607         n = 0;
 608         s = p->rpath_orig;
 609         while ((t=strchr(s, '$'))) {
 610                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 611                         return 0;
 612                 s = t+1;
 613                 n++;
 614         }
 615         if (n > SSIZE_MAX/PATH_MAX) return 0;
 616
 617         if (p->kernel_mapped) {
 618                 /* $ORIGIN searches cannot be performed for the main program
 619                  * when it is suid/sgid/AT_SECURE. This is because the
 620                  * pathname is under the control of the caller of execve.
 621                  * For libraries, however, $ORIGIN can be processed safely
 622                  * since the library's pathname came from a trusted source
 623                  * (either system paths or a call to dlopen). */
 624                 if (libc.secure)
 625                         return 0;
 626                 l = readlink("/proc/self/exe", buf, buf_size);
 627                 if (l == -1) switch (errno) {
 628                 case ENOENT:
 629                 case ENOTDIR:
 630                 case EACCES:
 631                         break;
 632                 default:
 633                         return -1;
 634                 }
 635                 if (l >= buf_size)
 636                         return 0;
 637                 buf[l] = 0;
 638                 origin = buf;
 639         } else {
 640                 origin = p->name;
 641         }
 642         t = strrchr(origin, '/');
 643         l = t ? t-origin : 0;
 644         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 645         if (!p->rpath) return -1;
 646
 647         d = p->rpath;
 648         s = p->rpath_orig;
 649         while ((t=strchr(s, '$'))) {
 650                 memcpy(d, s, t-s);
 651                 d += t-s;
 652                 memcpy(d, origin, l);
 653                 d += l;
 654                 /* It was determined previously that the '$' is followed
 655                  * either by "ORIGIN" or "{ORIGIN}". */
 656                 s = t + 7 + 2*(t[1]=='{');
 657         }
 658         strcpy(d, s);
 659         return 0;
 660 }
 661
 662 static void decode_dyn(struct dso *p)
 663 {
 664         size_t dyn[DYN_CNT] = {0};
 665         decode_vec(p->dynv, dyn, DYN_CNT);
 666         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 667         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 668         if (dyn[0]&(1<<DT_HASH))
 669                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 670         if (dyn[0]&(1<<DT_RPATH))
 671                 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
 672         if (dyn[0]&(1<<DT_RUNPATH))
 673                 p->rpath_orig = (void *)(p->strings + dyn[DT_RUNPATH]);
 674         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 675                 p->ghashtab = (void *)(p->base + *dyn);
 676         if (search_vec(p->dynv, dyn, DT_VERSYM))
 677                 p->versym = (void *)(p->base + *dyn);
 678 }
 679
 680 static struct dso *load_library(const char *name, struct dso *needed_by)
 681 {
 682         char buf[2*NAME_MAX+2];
 683         const char *pathname;
 684         unsigned char *map;
 685         struct dso *p, temp_dso = {0};
 686         int fd;
 687         struct stat st;
 688         size_t alloc_size;
 689         int n_th = 0;
 690         int is_self = 0;
 691
 692         if (!*name) {
 693                 errno = EINVAL;
 694                 return 0;
 695         }
 696
 697         /* Catch and block attempts to reload the implementation itself */
 698         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 699                 static const char *rp, reserved[] =
 700                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 701                 char *z = strchr(name, '.');
 702                 if (z) {
 703                         size_t l = z-name;
 704                         for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 705                         if (*rp) {
 706                                 if (ldd_mode) {
 707                                         /* Track which names have been resolved
 708                                          * and only report each one once. */
 709                                         static unsigned reported;
 710                                         unsigned mask = 1U<<(rp-reserved);
 711                                         if (!(reported & mask)) {
 712                                                 reported |= mask;
 713                                                 dprintf(1, "\t%s => %s (%p)\n",
 714                                                         name, ldso->name,
 715                                                         ldso->base);
 716                                         }
 717                                 }
 718                                 is_self = 1;
 719                         }
 720                 }
 721         }
 722         if (!strcmp(name, ldso->name)) is_self = 1;
 723         if (is_self) {
 724                 if (!ldso->prev) {
 725                         tail->next = ldso;
 726                         ldso->prev = tail;
 727                         tail = ldso->next ? ldso->next : ldso;
 728                 }
 729                 return ldso;
 730         }
 731         if (strchr(name, '/')) {
 732                 pathname = name;
 733                 fd = open(name, O_RDONLY|O_CLOEXEC);
 734         } else {
 735                 /* Search for the name to see if it's already loaded */
 736                 for (p=head->next; p; p=p->next) {
 737                         if (p->shortname && !strcmp(p->shortname, name)) {
 738                                 p->refcnt++;
 739                                 return p;
 740                         }
 741                 }
 742                 if (strlen(name) > NAME_MAX) return 0;
 743                 fd = -1;
 744                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 745                 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
 746                         if (fixup_rpath(p, buf, sizeof buf) < 0)
 747                                 fd = -2; /* Inhibit further search. */
 748                         if (p->rpath)
 749                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 750                 }
 751                 if (fd == -1) {
 752                         if (!sys_path) {
 753                                 char *prefix = 0;
 754                                 size_t prefix_len;
 755                                 if (ldso->name[0]=='/') {
 756                                         char *s, *t, *z;
 757                                         for (s=t=z=ldso->name; *s; s++)
 758                                                 if (*s=='/') z=t, t=s;
 759                                         prefix_len = z-ldso->name;
 760                                         if (prefix_len < PATH_MAX)
 761                                                 prefix = ldso->name;
 762                                 }
 763                                 if (!prefix) {
 764                                         prefix = "";
 765                                         prefix_len = 0;
 766                                 }
 767                                 char etc_ldso_path[prefix_len + 1
 768                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
 769                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
 770                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
 771                                         (int)prefix_len, prefix);
 772                                 FILE *f = fopen(etc_ldso_path, "rbe");
 773                                 if (f) {
 774                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
 775                                                 free(sys_path);
 776                                                 sys_path = "";
 777                                         }
 778                                         fclose(f);
 779                                 } else if (errno != ENOENT) {
 780                                         sys_path = "";
 781                                 }
 782                         }
 783                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
 784                         fd = path_open(name, sys_path, buf, sizeof buf);
 785                 }
 786                 pathname = buf;
 787         }
 788         if (fd < 0) return 0;
 789         if (fstat(fd, &st) < 0) {
 790                 close(fd);
 791                 return 0;
 792         }
 793         for (p=head->next; p; p=p->next) {
 794                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 795                         /* If this library was previously loaded with a
 796                          * pathname but a search found the same inode,
 797                          * setup its shortname so it can be found by name. */
 798                         if (!p->shortname && pathname != name)
 799                                 p->shortname = strrchr(p->name, '/')+1;
 800                         close(fd);
 801                         p->refcnt++;
 802                         return p;
 803                 }
 804         }
 805         map = noload ? 0 : map_library(fd, &temp_dso);
 806         close(fd);
 807         if (!map) return 0;
 808
 809         /* Allocate storage for the new DSO. When there is TLS, this
 810          * storage must include a reservation for all pre-existing
 811          * threads to obtain copies of both the new TLS, and an
 812          * extended DTV capable of storing an additional slot for
 813          * the newly-loaded DSO. */
 814         alloc_size = sizeof *p + strlen(pathname) + 1;
 815         if (runtime && temp_dso.tls_image) {
 816                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 817                         + sizeof(void *) * (tls_cnt+3);
 818                 n_th = libc.threads_minus_1 + 1;
 819                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 820                 else alloc_size += n_th * per_th;
 821         }
 822         p = calloc(1, alloc_size);
 823         if (!p) {
 824                 munmap(map, temp_dso.map_len);
 825                 return 0;
 826         }
 827         memcpy(p, &temp_dso, sizeof temp_dso);
 828         decode_dyn(p);
 829         p->dev = st.st_dev;
 830         p->ino = st.st_ino;
 831         p->refcnt = 1;
 832         p->needed_by = needed_by;
 833         p->name = p->buf;
 834         strcpy(p->name, pathname);
 835         /* Add a shortname only if name arg was not an explicit pathname. */
 836         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 837         if (p->tls_image) {
 838                 if (runtime && !libc.has_thread_pointer) {
 839                         munmap(map, p->map_len);
 840                         free(p);
 841                         errno = ENOSYS;
 842                         return 0;
 843                 }
 844                 p->tls_id = ++tls_cnt;
 845                 tls_align = MAXP2(tls_align, p->tls_align);
 846 #ifdef TLS_ABOVE_TP
 847                 p->tls_offset = tls_offset + ( (tls_align-1) &
 848                         -(tls_offset + (uintptr_t)p->tls_image) );
 849                 tls_offset += p->tls_size;
 850 #else
 851                 tls_offset += p->tls_size + p->tls_align - 1;
 852                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 853                         & (p->tls_align-1);
 854                 p->tls_offset = tls_offset;
 855 #endif
 856                 p->new_dtv = (void *)(-sizeof(size_t) &
 857                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 858                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 859         }
 860
 861         tail->next = p;
 862         p->prev = tail;
 863         tail = p;
 864
 865         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 866
 867         return p;
 868 }
 869
 870 static void load_deps(struct dso *p)
 871 {
 872         size_t i, ndeps=0;
 873         struct dso ***deps = &p->deps, **tmp, *dep;
 874         for (; p; p=p->next) {
 875                 for (i=0; p->dynv[i]; i+=2) {
 876                         if (p->dynv[i] != DT_NEEDED) continue;
 877                         dep = load_library(p->strings + p->dynv[i+1], p);
 878                         if (!dep) {
 879                                 error("Error loading shared library %s: %m (needed by %s)",
 880                                         p->strings + p->dynv[i+1], p->name);
 881                                 continue;
 882                         }
 883                         if (runtime) {
 884                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 885                                 if (!tmp) longjmp(*rtld_fail, 1);
 886                                 tmp[ndeps++] = dep;
 887                                 tmp[ndeps] = 0;
 888                                 *deps = tmp;
 889                         }
 890                 }
 891         }
 892 }
 893
 894 static void load_preload(char *s)
 895 {
 896         int tmp;
 897         char *z;
 898         for (z=s; *z; s=z) {
 899                 for (   ; *s && (isspace(*s) || *s==':'); s++);
 900                 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
 901                 tmp = *z;
 902                 *z = 0;
 903                 load_library(s, 0);
 904                 *z = tmp;
 905         }
 906 }
 907
 908 static void make_global(struct dso *p)
 909 {
 910         for (; p; p=p->next) p->global = 1;
 911 }
 912
 913 static void reloc_all(struct dso *p)
 914 {
 915         size_t dyn[DYN_CNT] = {0};
 916         for (; p; p=p->next) {
 917                 if (p->relocated) continue;
 918                 decode_vec(p->dynv, dyn, DYN_CNT);
 919 #ifdef NEED_ARCH_RELOCS
 920                 do_arch_relocs(p, head);
 921 #endif
 922                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 923                         2+(dyn[DT_PLTREL]==DT_RELA));
 924                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 925                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 926
 927                 if (p->relro_start != p->relro_end &&
 928                     mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ) < 0) {
 929                         error("Error relocating %s: RELRO protection failed: %m",
 930                                 p->name);
 931                 }
 932
 933                 p->relocated = 1;
 934         }
 935 }
 936
 937 static void kernel_mapped_dso(struct dso *p)
 938 {
 939         size_t min_addr = -1, max_addr = 0, cnt;
 940         Phdr *ph = p->phdr;
 941         for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
 942                 if (ph->p_type == PT_DYNAMIC) {
 943                         p->dynv = (void *)(p->base + ph->p_vaddr);
 944                 } else if (ph->p_type == PT_GNU_RELRO) {
 945                         p->relro_start = ph->p_vaddr & -PAGE_SIZE;
 946                         p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
 947                 }
 948                 if (ph->p_type != PT_LOAD) continue;
 949                 if (ph->p_vaddr < min_addr)
 950                         min_addr = ph->p_vaddr;
 951                 if (ph->p_vaddr+ph->p_memsz > max_addr)
 952                         max_addr = ph->p_vaddr+ph->p_memsz;
 953         }
 954         min_addr &= -PAGE_SIZE;
 955         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
 956         p->map = p->base + min_addr;
 957         p->map_len = max_addr - min_addr;
 958         p->kernel_mapped = 1;
 959 }
 960
 961 static void do_fini()
 962 {
 963         struct dso *p;
 964         size_t dyn[DYN_CNT] = {0};
 965         for (p=fini_head; p; p=p->fini_next) {
 966                 if (!p->constructed) continue;
 967                 decode_vec(p->dynv, dyn, DYN_CNT);
 968                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
 969                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
 970                         size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
 971                         while (n--) ((void (*)(void))*--fn)();
 972                 }
 973 #ifndef NO_LEGACY_INITFINI
 974                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
 975                         ((void (*)(void))(p->base + dyn[DT_FINI]))();
 976 #endif
 977         }
 978 }
 979
 980 static void do_init_fini(struct dso *p)
 981 {
 982         size_t dyn[DYN_CNT] = {0};
 983         int need_locking = libc.threads_minus_1;
 984         /* Allow recursive calls that arise when a library calls
 985          * dlopen from one of its constructors, but block any
 986          * other threads until all ctors have finished. */
 987         if (need_locking) pthread_mutex_lock(&init_fini_lock);
 988         for (; p; p=p->prev) {
 989                 if (p->constructed) continue;
 990                 p->constructed = 1;
 991                 decode_vec(p->dynv, dyn, DYN_CNT);
 992                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
 993                         p->fini_next = fini_head;
 994                         fini_head = p;
 995                 }
 996 #ifndef NO_LEGACY_INITFINI
 997                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
 998                         ((void (*)(void))(p->base + dyn[DT_INIT]))();
 999 #endif
1000                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1001                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1002                         size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
1003                         while (n--) ((void (*)(void))*fn++)();
1004                 }
1005                 if (!need_locking && libc.threads_minus_1) {
1006                         need_locking = 1;
1007                         pthread_mutex_lock(&init_fini_lock);
1008                 }
1009         }
1010         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1011 }
1012
1013 void _dl_debug_state(void)
1014 {
1015 }
1016
1017 void __reset_tls()
1018 {
1019         pthread_t self = __pthread_self();
1020         struct dso *p;
1021         for (p=head; p; p=p->next) {
1022                 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
1023                 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
1024                 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
1025                         p->tls_size - p->tls_len);
1026                 if (p->tls_id == (size_t)self->dtv[0]) break;
1027         }
1028 }
1029
1030 void *__copy_tls(unsigned char *mem)
1031 {
1032         pthread_t td;
1033         struct dso *p;
1034
1035         void **dtv = (void *)mem;
1036         dtv[0] = (void *)tls_cnt;
1037         if (!tls_cnt) {
1038                 td = (void *)(dtv+1);
1039                 td->dtv = td->dtv_copy = dtv;
1040                 return td;
1041         }
1042
1043 #ifdef TLS_ABOVE_TP
1044         mem += sizeof(void *) * (tls_cnt+1);
1045         mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
1046         td = (pthread_t)mem;
1047         mem += sizeof(struct pthread);
1048
1049         for (p=head; p; p=p->next) {
1050                 if (!p->tls_id) continue;
1051                 dtv[p->tls_id] = mem + p->tls_offset;
1052                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1053         }
1054 #else
1055         mem += libc.tls_size - sizeof(struct pthread);
1056         mem -= (uintptr_t)mem & (tls_align-1);
1057         td = (pthread_t)mem;
1058
1059         for (p=head; p; p=p->next) {
1060                 if (!p->tls_id) continue;
1061                 dtv[p->tls_id] = mem - p->tls_offset;
1062                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1063         }
1064 #endif
1065         td->dtv = td->dtv_copy = dtv;
1066         return td;
1067 }
1068
1069 void *__tls_get_new(size_t *v)
1070 {
1071         pthread_t self = __pthread_self();
1072
1073         /* Block signals to make accessing new TLS async-signal-safe */
1074         sigset_t set;
1075         __block_all_sigs(&set);
1076         if (v[0]<=(size_t)self->dtv[0]) {
1077                 __restore_sigs(&set);
1078                 return (char *)self->dtv[v[0]]+v[1];
1079         }
1080
1081         /* This is safe without any locks held because, if the caller
1082          * is able to request the Nth entry of the DTV, the DSO list
1083          * must be valid at least that far out and it was synchronized
1084          * at program startup or by an already-completed call to dlopen. */
1085         struct dso *p;
1086         for (p=head; p->tls_id != v[0]; p=p->next);
1087
1088         /* Get new DTV space from new DSO if needed */
1089         if (v[0] > (size_t)self->dtv[0]) {
1090                 void **newdtv = p->new_dtv +
1091                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
1092                 memcpy(newdtv, self->dtv,
1093                         ((size_t)self->dtv[0]+1) * sizeof(void *));
1094                 newdtv[0] = (void *)v[0];
1095                 self->dtv = self->dtv_copy = newdtv;
1096         }
1097
1098         /* Get new TLS memory from all new DSOs up to the requested one */
1099         unsigned char *mem;
1100         for (p=head; ; p=p->next) {
1101                 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1102                 mem = p->new_tls + (p->tls_size + p->tls_align)
1103                         * a_fetch_add(&p->new_tls_idx,1);
1104                 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem)
1105                         & (p->tls_align-1);
1106                 self->dtv[p->tls_id] = mem;
1107                 memcpy(mem, p->tls_image, p->tls_len);
1108                 if (p->tls_id == v[0]) break;
1109         }
1110         __restore_sigs(&set);
1111         return mem + v[1];
1112 }
1113
1114 static void update_tls_size()
1115 {
1116         libc.tls_size = ALIGN(
1117                 (1+tls_cnt) * sizeof(void *) +
1118                 tls_offset +
1119                 sizeof(struct pthread) +
1120                 tls_align * 2,
1121         tls_align);
1122 }
1123
1124 void *__dynlink(int argc, char **argv)
1125 {
1126         size_t aux[AUX_CNT] = {0};
1127         size_t i;
1128         Phdr *phdr;
1129         Ehdr *ehdr;
1130         static struct dso builtin_dsos[3];
1131         struct dso *const app = builtin_dsos+0;
1132         struct dso *const lib = builtin_dsos+1;
1133         struct dso *const vdso = builtin_dsos+2;
1134         char *env_preload=0;
1135         size_t vdso_base;
1136         size_t *auxv;
1137         char **envp = argv+argc+1;
1138         void *initial_tls;
1139
1140         /* Find aux vector just past environ[] */
1141         for (i=argc+1; argv[i]; i++)
1142                 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
1143                         env_path = argv[i]+16;
1144                 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
1145                         env_preload = argv[i]+11;
1146         auxv = (void *)(argv+i+1);
1147
1148         decode_vec(auxv, aux, AUX_CNT);
1149
1150         /* Only trust user/env if kernel says we're not suid/sgid */
1151         if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1152           || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
1153                 env_path = 0;
1154                 env_preload = 0;
1155                 libc.secure = 1;
1156         }
1157         libc.page_size = aux[AT_PAGESZ];
1158         libc.auxv = auxv;
1159
1160         /* If the dynamic linker was invoked as a program itself, AT_BASE
1161          * will not be set. In that case, we assume the base address is
1162          * the start of the page containing the PHDRs; I don't know any
1163          * better approach... */
1164         if (!aux[AT_BASE]) {
1165                 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
1166                 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
1167         }
1168
1169         /* The dynamic linker load address is passed by the kernel
1170          * in the AUX vector, so this is easy. */
1171         lib->base = (void *)aux[AT_BASE];
1172         lib->name = lib->shortname = "libc.so";
1173         lib->global = 1;
1174         ehdr = (void *)lib->base;
1175         lib->phnum = ehdr->e_phnum;
1176         lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
1177         lib->phentsize = ehdr->e_phentsize;
1178         kernel_mapped_dso(lib);
1179         decode_dyn(lib);
1180
1181         if (aux[AT_PHDR]) {
1182                 size_t interp_off = 0;
1183                 size_t tls_image = 0;
1184                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1185                 app->phdr = phdr = (void *)aux[AT_PHDR];
1186                 app->phnum = aux[AT_PHNUM];
1187                 app->phentsize = aux[AT_PHENT];
1188                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1189                         if (phdr->p_type == PT_PHDR)
1190                                 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1191                         else if (phdr->p_type == PT_INTERP)
1192                                 interp_off = (size_t)phdr->p_vaddr;
1193                         else if (phdr->p_type == PT_TLS) {
1194                                 tls_image = phdr->p_vaddr;
1195                                 app->tls_len = phdr->p_filesz;
1196                                 app->tls_size = phdr->p_memsz;
1197                                 app->tls_align = phdr->p_align;
1198                         }
1199                 }
1200                 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
1201                 if (interp_off) lib->name = (char *)app->base + interp_off;
1202                 if ((aux[0] & (1UL<<AT_EXECFN))
1203                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1204                         app->name = (char *)aux[AT_EXECFN];
1205                 else
1206                         app->name = argv[0];
1207                 kernel_mapped_dso(app);
1208         } else {
1209                 int fd;
1210                 char *ldname = argv[0];
1211                 size_t l = strlen(ldname);
1212                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1213                 *argv++ = (void *)-1;
1214                 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1215                         char *opt = argv[0]+2;
1216                         *argv++ = (void *)-1;
1217                         if (!*opt) {
1218                                 break;
1219                         } else if (!memcmp(opt, "list", 5)) {
1220                                 ldd_mode = 1;
1221                         } else if (!memcmp(opt, "library-path", 12)) {
1222                                 if (opt[12]=='=') env_path = opt+13;
1223                                 else if (opt[12]) *argv = 0;
1224                                 else if (*argv) env_path = *argv++;
1225                         } else if (!memcmp(opt, "preload", 7)) {
1226                                 if (opt[7]=='=') env_preload = opt+8;
1227                                 else if (opt[7]) *argv = 0;
1228                                 else if (*argv) env_preload = *argv++;
1229                         } else {
1230                                 argv[0] = 0;
1231                         }
1232                         argv[-1] = (void *)-1;
1233                 }
1234                 if (!argv[0]) {
1235                         dprintf(2, "musl libc\n"
1236                                 "Version %s\n"
1237                                 "Dynamic Program Loader\n"
1238                                 "Usage: %s [options] [--] pathname%s\n",
1239                                 __libc_get_version(), ldname,
1240                                 ldd_mode ? "" : " [args]");
1241                         _exit(1);
1242                 }
1243                 fd = open(argv[0], O_RDONLY);
1244                 if (fd < 0) {
1245                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1246                         _exit(1);
1247                 }
1248                 runtime = 1;
1249                 ehdr = (void *)map_library(fd, app);
1250                 if (!ehdr) {
1251                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1252                         _exit(1);
1253                 }
1254                 runtime = 0;
1255                 close(fd);
1256                 lib->name = ldname;
1257                 app->name = argv[0];
1258                 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1259                 /* Find the name that would have been used for the dynamic
1260                  * linker had ldd not taken its place. */
1261                 if (ldd_mode) {
1262                         for (i=0; i<app->phnum; i++) {
1263                                 if (app->phdr[i].p_type == PT_INTERP)
1264                                         lib->name = (void *)(app->base
1265                                                 + app->phdr[i].p_vaddr);
1266                         }
1267                         dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1268                 }
1269         }
1270         if (app->tls_size) {
1271                 app->tls_id = tls_cnt = 1;
1272 #ifdef TLS_ABOVE_TP
1273                 app->tls_offset = 0;
1274                 tls_offset = app->tls_size
1275                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1276                         & (app->tls_align-1) );
1277 #else
1278                 tls_offset = app->tls_offset = app->tls_size
1279                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1280                         & (app->tls_align-1) );
1281 #endif
1282                 tls_align = MAXP2(tls_align, app->tls_align);
1283         }
1284         app->global = 1;
1285         decode_dyn(app);
1286
1287         /* Attach to vdso, if provided by the kernel */
1288         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1289                 ehdr = (void *)vdso_base;
1290                 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1291                 vdso->phnum = ehdr->e_phnum;
1292                 vdso->phentsize = ehdr->e_phentsize;
1293                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1294                         if (phdr->p_type == PT_DYNAMIC)
1295                                 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1296                         if (phdr->p_type == PT_LOAD)
1297                                 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1298                 }
1299                 vdso->name = "";
1300                 vdso->shortname = "linux-gate.so.1";
1301                 vdso->global = 1;
1302                 decode_dyn(vdso);
1303                 vdso->prev = lib;
1304                 lib->next = vdso;
1305         }
1306
1307         /* Initial dso chain consists only of the app. We temporarily
1308          * append the dynamic linker/libc so we can relocate it, then
1309          * restore the initial chain in preparation for loading third
1310          * party libraries (preload/needed). */
1311         head = tail = app;
1312         ldso = lib;
1313         app->next = lib;
1314         reloc_all(lib);
1315         app->next = 0;
1316
1317         /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1318
1319         /* Donate unused parts of app and library mapping to malloc */
1320         reclaim_gaps(app);
1321         reclaim_gaps(lib);
1322
1323         /* Load preload/needed libraries, add their symbols to the global
1324          * namespace, and perform all remaining relocations. The main
1325          * program must be relocated LAST since it may contain copy
1326          * relocations which depend on libraries' relocations. */
1327         if (env_preload) load_preload(env_preload);
1328         load_deps(app);
1329         make_global(app);
1330
1331 #ifndef DYNAMIC_IS_RO
1332         for (i=0; app->dynv[i]; i+=2)
1333                 if (app->dynv[i]==DT_DEBUG)
1334                         app->dynv[i+1] = (size_t)&debug;
1335 #endif
1336
1337         reloc_all(app->next);
1338         reloc_all(app);
1339
1340         update_tls_size();
1341         if (libc.tls_size > sizeof builtin_tls) {
1342                 initial_tls = calloc(libc.tls_size, 1);
1343                 if (!initial_tls) {
1344                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1345                                 argv[0], libc.tls_size);
1346                         _exit(127);
1347                 }
1348         } else {
1349                 initial_tls = builtin_tls;
1350         }
1351         if (__init_tp(__copy_tls(initial_tls)) < 0 && tls_cnt) {
1352                 dprintf(2, "%s: Thread-local storage not supported by kernel.\n", argv[0]);
1353                 _exit(127);
1354         }
1355         static_tls_cnt = tls_cnt;
1356
1357         if (ldso_fail) _exit(127);
1358         if (ldd_mode) _exit(0);
1359
1360         /* Switch to runtime mode: any further failures in the dynamic
1361          * linker are a reportable failure rather than a fatal startup
1362          * error. If the dynamic loader (dlopen) will not be used, free
1363          * all memory used by the dynamic linker. */
1364         runtime = 1;
1365
1366         debug.ver = 1;
1367         debug.bp = _dl_debug_state;
1368         debug.head = head;
1369         debug.base = lib->base;
1370         debug.state = 0;
1371         _dl_debug_state();
1372
1373         __init_libc(envp, argv[0]);
1374         atexit(do_fini);
1375         errno = 0;
1376         do_init_fini(tail);
1377
1378         return (void *)aux[AT_ENTRY];
1379 }
1380
1381 void *dlopen(const char *file, int mode)
1382 {
1383         struct dso *volatile p, *orig_tail, *next;
1384         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1385         size_t i;
1386         int cs;
1387         jmp_buf jb;
1388
1389         if (!file) return head;
1390
1391         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1392         pthread_rwlock_wrlock(&lock);
1393         __inhibit_ptc();
1394
1395         p = 0;
1396         orig_tls_cnt = tls_cnt;
1397         orig_tls_offset = tls_offset;
1398         orig_tls_align = tls_align;
1399         orig_tail = tail;
1400         noload = mode & RTLD_NOLOAD;
1401
1402         rtld_fail = &jb;
1403         if (setjmp(*rtld_fail)) {
1404                 /* Clean up anything new that was (partially) loaded */
1405                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1406                         if (p->deps[i]->global < 0)
1407                                 p->deps[i]->global = 0;
1408                 for (p=orig_tail->next; p; p=next) {
1409                         next = p->next;
1410                         munmap(p->map, p->map_len);
1411                         while (p->td_index) {
1412                                 void *tmp = p->td_index->next;
1413                                 free(p->td_index);
1414                                 p->td_index = tmp;
1415                         }
1416                         free(p->deps);
1417                         free(p);
1418                 }
1419                 tls_cnt = orig_tls_cnt;
1420                 tls_offset = orig_tls_offset;
1421                 tls_align = orig_tls_align;
1422                 tail = orig_tail;
1423                 tail->next = 0;
1424                 p = 0;
1425                 errflag = 1;
1426                 goto end;
1427         } else p = load_library(file, head);
1428
1429         if (!p) {
1430                 snprintf(errbuf, sizeof errbuf, noload ?
1431                         "Library %s is not already loaded" :
1432                         "Error loading shared library %s: %m",
1433                         file);
1434                 errflag = 1;
1435                 goto end;
1436         }
1437
1438         /* First load handling */
1439         if (!p->deps) {
1440                 load_deps(p);
1441                 if (p->deps) for (i=0; p->deps[i]; i++)
1442                         if (!p->deps[i]->global)
1443                                 p->deps[i]->global = -1;
1444                 if (!p->global) p->global = -1;
1445                 reloc_all(p);
1446                 if (p->deps) for (i=0; p->deps[i]; i++)
1447                         if (p->deps[i]->global < 0)
1448                                 p->deps[i]->global = 0;
1449                 if (p->global < 0) p->global = 0;
1450         }
1451
1452         if (mode & RTLD_GLOBAL) {
1453                 if (p->deps) for (i=0; p->deps[i]; i++)
1454                         p->deps[i]->global = 1;
1455                 p->global = 1;
1456         }
1457
1458         update_tls_size();
1459         _dl_debug_state();
1460         orig_tail = tail;
1461 end:
1462         __release_ptc();
1463         if (p) gencnt++;
1464         pthread_rwlock_unlock(&lock);
1465         if (p) do_init_fini(orig_tail);
1466         pthread_setcancelstate(cs, 0);
1467         return p;
1468 }
1469
1470 static int invalid_dso_handle(void *h)
1471 {
1472         struct dso *p;
1473         for (p=head; p; p=p->next) if (h==p) return 0;
1474         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1475         errflag = 1;
1476         return 1;
1477 }
1478
1479 void *__tls_get_addr(size_t *);
1480
1481 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1482 {
1483         size_t i;
1484         uint32_t h = 0, gh = 0;
1485         Sym *sym;
1486         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1487                 if (p == RTLD_DEFAULT) {
1488                         p = head;
1489                 } else if (p == RTLD_NEXT) {
1490                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1491                         if (!p) p=head;
1492                         p = p->next;
1493                 }
1494                 struct symdef def = find_sym(p, s, 0);
1495                 if (!def.sym) goto failed;
1496                 if ((def.sym->st_info&0xf) == STT_TLS)
1497                         return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1498                 return def.dso->base + def.sym->st_value;
1499         }
1500         if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1501                 return 0;
1502         if (p->ghashtab) {
1503                 gh = gnu_hash(s);
1504                 sym = gnu_lookup(s, gh, p);
1505         } else {
1506                 h = sysv_hash(s);
1507                 sym = sysv_lookup(s, h, p);
1508         }
1509         if (sym && (sym->st_info&0xf) == STT_TLS)
1510                 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1511         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1512                 return p->base + sym->st_value;
1513         if (p->deps) for (i=0; p->deps[i]; i++) {
1514                 if (p->deps[i]->ghashtab) {
1515                         if (!gh) gh = gnu_hash(s);
1516                         sym = gnu_lookup(s, gh, p->deps[i]);
1517                 } else {
1518                         if (!h) h = sysv_hash(s);
1519                         sym = sysv_lookup(s, h, p->deps[i]);
1520                 }
1521                 if (sym && (sym->st_info&0xf) == STT_TLS)
1522                         return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1523                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1524                         return p->deps[i]->base + sym->st_value;
1525         }
1526 failed:
1527         errflag = 1;
1528         snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1529         return 0;
1530 }
1531
1532 int __dladdr(const void *addr, Dl_info *info)
1533 {
1534         struct dso *p;
1535         Sym *sym;
1536         uint32_t nsym;
1537         char *strings;
1538         size_t i;
1539         void *best = 0;
1540         char *bestname;
1541
1542         pthread_rwlock_rdlock(&lock);
1543         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1544         pthread_rwlock_unlock(&lock);
1545
1546         if (!p) return 0;
1547
1548         sym = p->syms;
1549         strings = p->strings;
1550         if (p->hashtab) {
1551                 nsym = p->hashtab[1];
1552         } else {
1553                 uint32_t *buckets;
1554                 uint32_t *hashval;
1555                 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1556                 sym += p->ghashtab[1];
1557                 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1558                         if (buckets[i] > nsym)
1559                                 nsym = buckets[i];
1560                 }
1561                 if (nsym) {
1562                         nsym -= p->ghashtab[1];
1563                         hashval = buckets + p->ghashtab[0] + nsym;
1564                         do nsym++;
1565                         while (!(*hashval++ & 1));
1566                 }
1567         }
1568
1569         for (; nsym; nsym--, sym++) {
1570                 if (sym->st_value
1571                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1572                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1573                         void *symaddr = p->base + sym->st_value;
1574                         if (symaddr > addr || symaddr < best)
1575                                 continue;
1576                         best = symaddr;
1577                         bestname = strings + sym->st_name;
1578                         if (addr == symaddr)
1579                                 break;
1580                 }
1581         }
1582
1583         if (!best) return 0;
1584
1585         info->dli_fname = p->name;
1586         info->dli_fbase = p->base;
1587         info->dli_sname = bestname;
1588         info->dli_saddr = best;
1589
1590         return 1;
1591 }
1592
1593 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1594 {
1595         void *res;
1596         pthread_rwlock_rdlock(&lock);
1597         res = do_dlsym(p, s, ra);
1598         pthread_rwlock_unlock(&lock);
1599         return res;
1600 }
1601
1602 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1603 {
1604         struct dso *current;
1605         struct dl_phdr_info info;
1606         int ret = 0;
1607         for(current = head; current;) {
1608                 info.dlpi_addr      = (uintptr_t)current->base;
1609                 info.dlpi_name      = current->name;
1610                 info.dlpi_phdr      = current->phdr;
1611                 info.dlpi_phnum     = current->phnum;
1612                 info.dlpi_adds      = gencnt;
1613                 info.dlpi_subs      = 0;
1614                 info.dlpi_tls_modid = current->tls_id;
1615                 info.dlpi_tls_data  = current->tls_image;
1616
1617                 ret = (callback)(&info, sizeof (info), data);
1618
1619                 if (ret != 0) break;
1620
1621                 pthread_rwlock_rdlock(&lock);
1622                 current = current->next;
1623                 pthread_rwlock_unlock(&lock);
1624         }
1625         return ret;
1626 }
1627 #else
1628 static int invalid_dso_handle(void *h)
1629 {
1630         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1631         errflag = 1;
1632         return 1;
1633 }
1634 void *dlopen(const char *file, int mode)
1635 {
1636         strcpy(errbuf, "Dynamic loading not supported");
1637         errflag = 1;
1638         return 0;
1639 }
1640 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1641 {
1642         errflag = 1;
1643         snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1644         return 0;
1645 }
1646 int __dladdr (const void *addr, Dl_info *info)
1647 {
1648         return 0;
1649 }
1650 #endif
1651
1652 int __dlinfo(void *dso, int req, void *res)
1653 {
1654         if (invalid_dso_handle(dso)) return -1;
1655         if (req != RTLD_DI_LINKMAP) {
1656                 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1657                 errflag = 1;
1658                 return -1;
1659         }
1660         *(struct link_map **)res = dso;
1661         return 0;
1662 }
1663
1664 char *dlerror()
1665 {
1666         if (!errflag) return 0;
1667         errflag = 0;
1668         return errbuf;
1669 }
1670
1671 int dlclose(void *p)
1672 {
1673         return invalid_dso_handle(p);
1674 }