nsz Git - musl/blob - src/ldso/dynlink.c

   1 #define _GNU_SOURCE
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <unistd.h>
   6 #include <stdint.h>
   7 #include <elf.h>
   8 #include <sys/mman.h>
   9 #include <limits.h>
  10 #include <fcntl.h>
  11 #include <sys/stat.h>
  12 #include <errno.h>
  13 #include <link.h>
  14 #include <setjmp.h>
  15 #include <pthread.h>
  16 #include <ctype.h>
  17 #include <dlfcn.h>
  18 #include "pthread_impl.h"
  19 #include "libc.h"
  20
  21 static int errflag;
  22 static char errbuf[128];
  23
  24 #ifdef SHARED
  25
  26 #if ULONG_MAX == 0xffffffff
  27 typedef Elf32_Ehdr Ehdr;
  28 typedef Elf32_Phdr Phdr;
  29 typedef Elf32_Sym Sym;
  30 #define R_TYPE(x) ((x)&255)
  31 #define R_SYM(x) ((x)>>8)
  32 #else
  33 typedef Elf64_Ehdr Ehdr;
  34 typedef Elf64_Phdr Phdr;
  35 typedef Elf64_Sym Sym;
  36 #define R_TYPE(x) ((x)&0xffffffff)
  37 #define R_SYM(x) ((x)>>32)
  38 #endif
  39
  40 #define MAXP2(a,b) (-(-(a)&-(b)))
  41 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  42
  43 struct debug {
  44         int ver;
  45         void *head;
  46         void (*bp)(void);
  47         int state;
  48         void *base;
  49 };
  50
  51 struct dso {
  52         unsigned char *base;
  53         char *name;
  54         size_t *dynv;
  55         struct dso *next, *prev;
  56
  57         Phdr *phdr;
  58         int phnum;
  59         int refcnt;
  60         Sym *syms;
  61         uint32_t *hashtab;
  62         uint32_t *ghashtab;
  63         int16_t *versym;
  64         char *strings;
  65         unsigned char *map;
  66         size_t map_len;
  67         dev_t dev;
  68         ino_t ino;
  69         signed char global;
  70         char relocated;
  71         char constructed;
  72         char kernel_mapped;
  73         struct dso **deps, *needed_by;
  74         char *rpath_orig, *rpath;
  75         void *tls_image;
  76         size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
  77         void **new_dtv;
  78         unsigned char *new_tls;
  79         int new_dtv_idx, new_tls_idx;
  80         struct dso *fini_next;
  81         char *shortname;
  82         char buf[];
  83 };
  84
  85 struct symdef {
  86         Sym *sym;
  87         struct dso *dso;
  88 };
  89
  90 #include "reloc.h"
  91
  92 void __init_ssp(size_t *);
  93 void *__install_initial_tls(void *);
  94 void __init_libc(char **, char *);
  95
  96 static struct dso *head, *tail, *ldso, *fini_head;
  97 static char *env_path, *sys_path;
  98 static unsigned long long gencnt;
  99 static int ssp_used;
 100 static int runtime;
 101 static int ldd_mode;
 102 static int ldso_fail;
 103 static int noload;
 104 static jmp_buf *rtld_fail;
 105 static pthread_rwlock_t lock;
 106 static struct debug debug;
 107 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
 108 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 109
 110 struct debug *_dl_debug_addr = &debug;
 111
 112 #define AUX_CNT 38
 113 #define DYN_CNT 34
 114
 115 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 116 {
 117         memset(a, 0, cnt*sizeof(size_t));
 118         for (; v[0]; v+=2) if (v[0]<cnt) {
 119                 a[0] |= 1ULL<<v[0];
 120                 a[v[0]] = v[1];
 121         }
 122 }
 123
 124 static int search_vec(size_t *v, size_t *r, size_t key)
 125 {
 126         for (; v[0]!=key; v+=2)
 127                 if (!v[0]) return 0;
 128         *r = v[1];
 129         return 1;
 130 }
 131
 132 static uint32_t sysv_hash(const char *s0)
 133 {
 134         const unsigned char *s = (void *)s0;
 135         uint_fast32_t h = 0;
 136         while (*s) {
 137                 h = 16*h + *s++;
 138                 h ^= h>>24 & 0xf0;
 139         }
 140         return h & 0xfffffff;
 141 }
 142
 143 static uint32_t gnu_hash(const char *s0)
 144 {
 145         const unsigned char *s = (void *)s0;
 146         uint_fast32_t h = 5381;
 147         for (; *s; s++)
 148                 h = h*33 + *s;
 149         return h;
 150 }
 151
 152 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 153 {
 154         size_t i;
 155         Sym *syms = dso->syms;
 156         uint32_t *hashtab = dso->hashtab;
 157         char *strings = dso->strings;
 158         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 159                 if ((!dso->versym || dso->versym[i] >= 0)
 160                     && (!strcmp(s, strings+syms[i].st_name)))
 161                         return syms+i;
 162         }
 163         return 0;
 164 }
 165
 166 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 167 {
 168         Sym *syms = dso->syms;
 169         char *strings = dso->strings;
 170         uint32_t *hashtab = dso->ghashtab;
 171         uint32_t nbuckets = hashtab[0];
 172         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 173         uint32_t h2;
 174         uint32_t *hashval;
 175         uint32_t i = buckets[h1 % nbuckets];
 176
 177         if (!i) return 0;
 178
 179         hashval = buckets + nbuckets + (i - hashtab[1]);
 180
 181         for (h1 |= 1; ; i++) {
 182                 h2 = *hashval++;
 183                 if ((!dso->versym || dso->versym[i] >= 0)
 184                     && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
 185                         return syms+i;
 186                 if (h2 & 1) break;
 187         }
 188
 189         return 0;
 190 }
 191
 192 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 193 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 194
 195 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 196 {
 197         uint32_t h = 0, gh = 0;
 198         struct symdef def = {0};
 199         if (dso->ghashtab) {
 200                 gh = gnu_hash(s);
 201                 if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 202         } else {
 203                 h = sysv_hash(s);
 204                 if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 205         }
 206         for (; dso; dso=dso->next) {
 207                 Sym *sym;
 208                 if (!dso->global) continue;
 209                 if (dso->ghashtab) {
 210                         if (!gh) gh = gnu_hash(s);
 211                         sym = gnu_lookup(s, gh, dso);
 212                 } else {
 213                         if (!h) h = sysv_hash(s);
 214                         sym = sysv_lookup(s, h, dso);
 215                 }
 216                 if (!sym) continue;
 217                 if (!sym->st_shndx)
 218                         if (need_def || (sym->st_info&0xf) == STT_TLS)
 219                                 continue;
 220                 if (!sym->st_value)
 221                         if ((sym->st_info&0xf) != STT_TLS)
 222                                 continue;
 223                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 224                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 225
 226                 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
 227                 def.sym = sym;
 228                 def.dso = dso;
 229                 if (sym->st_info>>4 == STB_GLOBAL) break;
 230         }
 231         return def;
 232 }
 233
 234 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 235 {
 236         unsigned char *base = dso->base;
 237         Sym *syms = dso->syms;
 238         char *strings = dso->strings;
 239         Sym *sym;
 240         const char *name;
 241         void *ctx;
 242         int type;
 243         int sym_index;
 244         struct symdef def;
 245
 246         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 247                 type = R_TYPE(rel[1]);
 248                 sym_index = R_SYM(rel[1]);
 249                 if (sym_index) {
 250                         sym = syms + sym_index;
 251                         name = strings + sym->st_name;
 252                         ctx = IS_COPY(type) ? head->next : head;
 253                         def = find_sym(ctx, name, IS_PLT(type));
 254                         if (!def.sym && sym->st_info>>4 != STB_WEAK) {
 255                                 snprintf(errbuf, sizeof errbuf,
 256                                         "Error relocating %s: %s: symbol not found",
 257                                         dso->name, name);
 258                                 if (runtime) longjmp(*rtld_fail, 1);
 259                                 dprintf(2, "%s\n", errbuf);
 260                                 ldso_fail = 1;
 261                                 continue;
 262                         }
 263                 } else {
 264                         sym = 0;
 265                         def.sym = 0;
 266                         def.dso = 0;
 267                 }
 268                 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
 269                         stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
 270                         def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
 271         }
 272 }
 273
 274 /* A huge hack: to make up for the wastefulness of shared libraries
 275  * needing at least a page of dirty memory even if they have no global
 276  * data, we reclaim the gaps at the beginning and end of writable maps
 277  * and "donate" them to the heap by setting up minimal malloc
 278  * structures and then freeing them. */
 279
 280 static void reclaim(unsigned char *base, size_t start, size_t end)
 281 {
 282         size_t *a, *z;
 283         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 284         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 285         if (start>end || end-start < 4*sizeof(size_t)) return;
 286         a = (size_t *)(base + start);
 287         z = (size_t *)(base + end);
 288         a[-2] = 1;
 289         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 290         z[1] = 1;
 291         free(a);
 292 }
 293
 294 static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phcnt)
 295 {
 296         for (; phcnt--; ph=(void *)((char *)ph+phent)) {
 297                 if (ph->p_type!=PT_LOAD) continue;
 298                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 299                 reclaim(base, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 300                 reclaim(base, ph->p_vaddr+ph->p_memsz,
 301                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 302         }
 303 }
 304
 305 static void *map_library(int fd, struct dso *dso)
 306 {
 307         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 308         void *allocated_buf=0;
 309         size_t phsize;
 310         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 311         size_t this_min, this_max;
 312         off_t off_start;
 313         Ehdr *eh;
 314         Phdr *ph, *ph0;
 315         unsigned prot;
 316         unsigned char *map=MAP_FAILED, *base;
 317         size_t dyn=0;
 318         size_t tls_image=0;
 319         size_t i;
 320
 321         ssize_t l = read(fd, buf, sizeof buf);
 322         eh = buf;
 323         if (l<0) return 0;
 324         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 325                 goto noexec;
 326         phsize = eh->e_phentsize * eh->e_phnum;
 327         if (phsize > sizeof buf - sizeof *eh) {
 328                 allocated_buf = malloc(phsize);
 329                 if (!allocated_buf) return 0;
 330                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 331                 if (l < 0) goto error;
 332                 if (l != phsize) goto noexec;
 333                 ph = ph0 = allocated_buf;
 334         } else if (eh->e_phoff + phsize > l) {
 335                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 336                 if (l < 0) goto error;
 337                 if (l != phsize) goto noexec;
 338                 ph = ph0 = (void *)(buf + 1);
 339         } else {
 340                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 341         }
 342         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 343                 if (ph->p_type == PT_DYNAMIC)
 344                         dyn = ph->p_vaddr;
 345                 if (ph->p_type == PT_TLS) {
 346                         tls_image = ph->p_vaddr;
 347                         dso->tls_align = ph->p_align;
 348                         dso->tls_len = ph->p_filesz;
 349                         dso->tls_size = ph->p_memsz;
 350                 }
 351                 if (ph->p_type != PT_LOAD) continue;
 352                 if (ph->p_vaddr < addr_min) {
 353                         addr_min = ph->p_vaddr;
 354                         off_start = ph->p_offset;
 355                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 356                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 357                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 358                 }
 359                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 360                         addr_max = ph->p_vaddr+ph->p_memsz;
 361                 }
 362         }
 363         if (!dyn) goto noexec;
 364         addr_max += PAGE_SIZE-1;
 365         addr_max &= -PAGE_SIZE;
 366         addr_min &= -PAGE_SIZE;
 367         off_start &= -PAGE_SIZE;
 368         map_len = addr_max - addr_min + off_start;
 369         /* The first time, we map too much, possibly even more than
 370          * the length of the file. This is okay because we will not
 371          * use the invalid part; we just need to reserve the right
 372          * amount of virtual address space to map over later. */
 373         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 374         if (map==MAP_FAILED) goto error;
 375         /* If the loaded file is not relocatable and the requested address is
 376          * not available, then the load operation must fail. */
 377         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 378                 errno = EBUSY;
 379                 goto error;
 380         }
 381         base = map - addr_min;
 382         dso->phdr = 0;
 383         dso->phnum = 0;
 384         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 385                 if (ph->p_type != PT_LOAD) continue;
 386                 /* Check if the programs headers are in this load segment, and
 387                  * if so, record the address for use by dl_iterate_phdr. */
 388                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 389                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 390                         dso->phdr = (void *)(base + ph->p_vaddr
 391                                 + (eh->e_phoff-ph->p_offset));
 392                         dso->phnum = eh->e_phnum;
 393                 }
 394                 /* Reuse the existing mapping for the lowest-address LOAD */
 395                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 396                 this_min = ph->p_vaddr & -PAGE_SIZE;
 397                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 398                 off_start = ph->p_offset & -PAGE_SIZE;
 399                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 400                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 401                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 402                 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 403                         goto error;
 404                 if (ph->p_memsz > ph->p_filesz) {
 405                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 406                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 407                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 408                         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)
 409                                 goto error;
 410                 }
 411         }
 412         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 413                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 414                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
 415                                 goto error;
 416                         break;
 417                 }
 418         if (!runtime) reclaim_gaps(base, ph0, eh->e_phentsize, eh->e_phnum);
 419         dso->map = map;
 420         dso->map_len = map_len;
 421         dso->base = base;
 422         dso->dynv = (void *)(base+dyn);
 423         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 424         free(allocated_buf);
 425         return map;
 426 noexec:
 427         errno = ENOEXEC;
 428 error:
 429         if (map!=MAP_FAILED) munmap(map, map_len);
 430         free(allocated_buf);
 431         return 0;
 432 }
 433
 434 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 435 {
 436         size_t l;
 437         int fd;
 438         for (;;) {
 439                 s += strspn(s, ":\n");
 440                 l = strcspn(s, ":\n");
 441                 if (l-1 >= INT_MAX) return -1;
 442                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
 443                         continue;
 444                 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 445                 s += l;
 446         }
 447 }
 448
 449 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 450 {
 451         size_t n, l;
 452         const char *s, *t, *origin;
 453         char *d;
 454         if (p->rpath) return 0;
 455         if (!p->rpath_orig) return -1;
 456         if (!strchr(p->rpath_orig, '$')) {
 457                 p->rpath = p->rpath_orig;
 458                 return 0;
 459         }
 460         n = 0;
 461         s = p->rpath_orig;
 462         while ((t=strchr(s, '$'))) {
 463                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 464                         return -1;
 465                 s = t+1;
 466                 n++;
 467         }
 468         if (n > SSIZE_MAX/PATH_MAX) return -1;
 469
 470         if (p->kernel_mapped) {
 471                 /* $ORIGIN searches cannot be performed for the main program
 472                  * when it is suid/sgid/AT_SECURE. This is because the
 473                  * pathname is under the control of the caller of execve.
 474                  * For libraries, however, $ORIGIN can be processed safely
 475                  * since the library's pathname came from a trusted source
 476                  * (either system paths or a call to dlopen). */
 477                 if (libc.secure)
 478                         return -1;
 479                 l = readlink("/proc/self/exe", buf, buf_size);
 480                 if (l >= buf_size)
 481                         return -1;
 482                 buf[l] = 0;
 483                 origin = buf;
 484         } else {
 485                 origin = p->name;
 486         }
 487         t = strrchr(origin, '/');
 488         l = t ? t-origin : 0;
 489         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 490         if (!p->rpath) return -1;
 491
 492         d = p->rpath;
 493         s = p->rpath_orig;
 494         while ((t=strchr(s, '$'))) {
 495                 memcpy(d, s, t-s);
 496                 d += t-s;
 497                 memcpy(d, origin, l);
 498                 d += l;
 499                 /* It was determined previously that the '$' is followed
 500                  * either by "ORIGIN" or "{ORIGIN}". */
 501                 s = t + 7 + 2*(t[1]=='{');
 502         }
 503         strcpy(d, s);
 504         return 0;
 505 }
 506
 507 static void decode_dyn(struct dso *p)
 508 {
 509         size_t dyn[DYN_CNT] = {0};
 510         decode_vec(p->dynv, dyn, DYN_CNT);
 511         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 512         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 513         if (dyn[0]&(1<<DT_HASH))
 514                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 515         if (dyn[0]&(1<<DT_RPATH))
 516                 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
 517         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 518                 p->ghashtab = (void *)(p->base + *dyn);
 519         if (search_vec(p->dynv, dyn, DT_VERSYM))
 520                 p->versym = (void *)(p->base + *dyn);
 521 }
 522
 523 static struct dso *load_library(const char *name, struct dso *needed_by)
 524 {
 525         char buf[2*NAME_MAX+2];
 526         const char *pathname;
 527         unsigned char *map;
 528         struct dso *p, temp_dso = {0};
 529         int fd;
 530         struct stat st;
 531         size_t alloc_size;
 532         int n_th = 0;
 533         int is_self = 0;
 534
 535         /* Catch and block attempts to reload the implementation itself */
 536         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 537                 static const char *rp, reserved[] =
 538                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 539                 char *z = strchr(name, '.');
 540                 if (z) {
 541                         size_t l = z-name;
 542                         for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 543                         if (*rp) {
 544                                 if (ldd_mode) {
 545                                         /* Track which names have been resolved
 546                                          * and only report each one once. */
 547                                         static unsigned reported;
 548                                         unsigned mask = 1U<<(rp-reserved);
 549                                         if (!(reported & mask)) {
 550                                                 reported |= mask;
 551                                                 dprintf(1, "\t%s => %s (%p)\n",
 552                                                         name, ldso->name,
 553                                                         ldso->base);
 554                                         }
 555                                 }
 556                                 is_self = 1;
 557                         }
 558                 }
 559         }
 560         if (!strcmp(name, ldso->name)) is_self = 1;
 561         if (is_self) {
 562                 if (!ldso->prev) {
 563                         tail->next = ldso;
 564                         ldso->prev = tail;
 565                         tail = ldso->next ? ldso->next : ldso;
 566                 }
 567                 return ldso;
 568         }
 569         if (strchr(name, '/')) {
 570                 pathname = name;
 571                 fd = open(name, O_RDONLY|O_CLOEXEC);
 572         } else {
 573                 /* Search for the name to see if it's already loaded */
 574                 for (p=head->next; p; p=p->next) {
 575                         if (p->shortname && !strcmp(p->shortname, name)) {
 576                                 p->refcnt++;
 577                                 return p;
 578                         }
 579                 }
 580                 if (strlen(name) > NAME_MAX) return 0;
 581                 fd = -1;
 582                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 583                 for (p=needed_by; fd < 0 && p; p=p->needed_by)
 584                         if (!fixup_rpath(p, buf, sizeof buf))
 585                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 586                 if (fd < 0) {
 587                         if (!sys_path) {
 588                                 char *prefix = 0;
 589                                 size_t prefix_len;
 590                                 if (ldso->name[0]=='/') {
 591                                         char *s, *t, *z;
 592                                         for (s=t=z=ldso->name; *s; s++)
 593                                                 if (*s=='/') z=t, t=s;
 594                                         prefix_len = z-ldso->name;
 595                                         if (prefix_len < PATH_MAX)
 596                                                 prefix = ldso->name;
 597                                 }
 598                                 if (!prefix) {
 599                                         prefix = "";
 600                                         prefix_len = 0;
 601                                 }
 602                                 char etc_ldso_path[prefix_len + 1
 603                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
 604                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
 605                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
 606                                         (int)prefix_len, prefix);
 607                                 FILE *f = fopen(etc_ldso_path, "rbe");
 608                                 if (f) {
 609                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
 610                                                 free(sys_path);
 611                                                 sys_path = "";
 612                                         }
 613                                         fclose(f);
 614                                 } else if (errno != ENOENT) {
 615                                         sys_path = "";
 616                                 }
 617                         }
 618                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
 619                         fd = path_open(name, sys_path, buf, sizeof buf);
 620                 }
 621                 pathname = buf;
 622         }
 623         if (fd < 0) return 0;
 624         if (fstat(fd, &st) < 0) {
 625                 close(fd);
 626                 return 0;
 627         }
 628         for (p=head->next; p; p=p->next) {
 629                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 630                         /* If this library was previously loaded with a
 631                          * pathname but a search found the same inode,
 632                          * setup its shortname so it can be found by name. */
 633                         if (!p->shortname && pathname != name)
 634                                 p->shortname = strrchr(p->name, '/')+1;
 635                         close(fd);
 636                         p->refcnt++;
 637                         return p;
 638                 }
 639         }
 640         map = noload ? 0 : map_library(fd, &temp_dso);
 641         close(fd);
 642         if (!map) return 0;
 643
 644         /* Allocate storage for the new DSO. When there is TLS, this
 645          * storage must include a reservation for all pre-existing
 646          * threads to obtain copies of both the new TLS, and an
 647          * extended DTV capable of storing an additional slot for
 648          * the newly-loaded DSO. */
 649         alloc_size = sizeof *p + strlen(pathname) + 1;
 650         if (runtime && temp_dso.tls_image) {
 651                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 652                         + sizeof(void *) * (tls_cnt+3);
 653                 n_th = libc.threads_minus_1 + 1;
 654                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 655                 else alloc_size += n_th * per_th;
 656         }
 657         p = calloc(1, alloc_size);
 658         if (!p) {
 659                 munmap(map, temp_dso.map_len);
 660                 return 0;
 661         }
 662         memcpy(p, &temp_dso, sizeof temp_dso);
 663         decode_dyn(p);
 664         p->dev = st.st_dev;
 665         p->ino = st.st_ino;
 666         p->refcnt = 1;
 667         p->needed_by = needed_by;
 668         p->name = p->buf;
 669         strcpy(p->name, pathname);
 670         /* Add a shortname only if name arg was not an explicit pathname. */
 671         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 672         if (p->tls_image) {
 673                 if (runtime && !__pthread_self_init()) {
 674                         munmap(map, p->map_len);
 675                         free(p);
 676                         return 0;
 677                 }
 678                 p->tls_id = ++tls_cnt;
 679                 tls_align = MAXP2(tls_align, p->tls_align);
 680 #ifdef TLS_ABOVE_TP
 681                 p->tls_offset = tls_offset + ( (tls_align-1) &
 682                         -(tls_offset + (uintptr_t)p->tls_image) );
 683                 tls_offset += p->tls_size;
 684 #else
 685                 tls_offset += p->tls_size + p->tls_align - 1;
 686                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 687                         & (p->tls_align-1);
 688                 p->tls_offset = tls_offset;
 689 #endif
 690                 p->new_dtv = (void *)(-sizeof(size_t) &
 691                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 692                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 693         }
 694
 695         tail->next = p;
 696         p->prev = tail;
 697         tail = p;
 698
 699         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 700
 701         return p;
 702 }
 703
 704 static void load_deps(struct dso *p)
 705 {
 706         size_t i, ndeps=0;
 707         struct dso ***deps = &p->deps, **tmp, *dep;
 708         for (; p; p=p->next) {
 709                 for (i=0; p->dynv[i]; i+=2) {
 710                         if (p->dynv[i] != DT_NEEDED) continue;
 711                         dep = load_library(p->strings + p->dynv[i+1], p);
 712                         if (!dep) {
 713                                 snprintf(errbuf, sizeof errbuf,
 714                                         "Error loading shared library %s: %m (needed by %s)",
 715                                         p->strings + p->dynv[i+1], p->name);
 716                                 if (runtime) longjmp(*rtld_fail, 1);
 717                                 dprintf(2, "%s\n", errbuf);
 718                                 ldso_fail = 1;
 719                                 continue;
 720                         }
 721                         if (runtime) {
 722                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 723                                 if (!tmp) longjmp(*rtld_fail, 1);
 724                                 tmp[ndeps++] = dep;
 725                                 tmp[ndeps] = 0;
 726                                 *deps = tmp;
 727                         }
 728                 }
 729         }
 730 }
 731
 732 static void load_preload(char *s)
 733 {
 734         int tmp;
 735         char *z;
 736         for (z=s; *z; s=z) {
 737                 for (   ; *s && isspace(*s); s++);
 738                 for (z=s; *z && !isspace(*z); z++);
 739                 tmp = *z;
 740                 *z = 0;
 741                 load_library(s, 0);
 742                 *z = tmp;
 743         }
 744 }
 745
 746 static void make_global(struct dso *p)
 747 {
 748         for (; p; p=p->next) p->global = 1;
 749 }
 750
 751 static void reloc_all(struct dso *p)
 752 {
 753         size_t dyn[DYN_CNT] = {0};
 754         for (; p; p=p->next) {
 755                 if (p->relocated) continue;
 756                 decode_vec(p->dynv, dyn, DYN_CNT);
 757 #ifdef NEED_ARCH_RELOCS
 758                 do_arch_relocs(p, head);
 759 #endif
 760                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 761                         2+(dyn[DT_PLTREL]==DT_RELA));
 762                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 763                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 764                 p->relocated = 1;
 765         }
 766 }
 767
 768 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
 769 {
 770         for (; cnt--; ph = (void *)((char *)ph + stride))
 771                 if (ph->p_type == PT_DYNAMIC)
 772                         return ph->p_vaddr;
 773         return 0;
 774 }
 775
 776 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
 777 {
 778         size_t min_addr = -1, max_addr = 0;
 779         for (; cnt--; ph = (void *)((char *)ph + stride)) {
 780                 if (ph->p_type != PT_LOAD) continue;
 781                 if (ph->p_vaddr < min_addr)
 782                         min_addr = ph->p_vaddr;
 783                 if (ph->p_vaddr+ph->p_memsz > max_addr)
 784                         max_addr = ph->p_vaddr+ph->p_memsz;
 785         }
 786         min_addr &= -PAGE_SIZE;
 787         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
 788         p->map = p->base + min_addr;
 789         p->map_len = max_addr - min_addr;
 790 }
 791
 792 static void do_fini()
 793 {
 794         struct dso *p;
 795         size_t dyn[DYN_CNT] = {0};
 796         for (p=fini_head; p; p=p->fini_next) {
 797                 if (!p->constructed) continue;
 798                 decode_vec(p->dynv, dyn, DYN_CNT);
 799                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
 800                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
 801                         size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
 802                         while (n--) ((void (*)(void))*--fn)();
 803                 }
 804 #ifndef NO_LEGACY_INITFINI
 805                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
 806                         ((void (*)(void))(p->base + dyn[DT_FINI]))();
 807 #endif
 808         }
 809 }
 810
 811 static void do_init_fini(struct dso *p)
 812 {
 813         size_t dyn[DYN_CNT] = {0};
 814         int need_locking = libc.threads_minus_1;
 815         /* Allow recursive calls that arise when a library calls
 816          * dlopen from one of its constructors, but block any
 817          * other threads until all ctors have finished. */
 818         if (need_locking) pthread_mutex_lock(&init_fini_lock);
 819         for (; p; p=p->prev) {
 820                 if (p->constructed) continue;
 821                 p->constructed = 1;
 822                 decode_vec(p->dynv, dyn, DYN_CNT);
 823                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
 824                         p->fini_next = fini_head;
 825                         fini_head = p;
 826                 }
 827 #ifndef NO_LEGACY_INITFINI
 828                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
 829                         ((void (*)(void))(p->base + dyn[DT_INIT]))();
 830 #endif
 831                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
 832                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
 833                         size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
 834                         while (n--) ((void (*)(void))*fn++)();
 835                 }
 836                 if (!need_locking && libc.threads_minus_1) {
 837                         need_locking = 1;
 838                         pthread_mutex_lock(&init_fini_lock);
 839                 }
 840         }
 841         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
 842 }
 843
 844 void _dl_debug_state(void)
 845 {
 846 }
 847
 848 void __reset_tls()
 849 {
 850         pthread_t self = __pthread_self();
 851         struct dso *p;
 852         for (p=head; p; p=p->next) {
 853                 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
 854                 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
 855                 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
 856                         p->tls_size - p->tls_len);
 857                 if (p->tls_id == (size_t)self->dtv[0]) break;
 858         }
 859 }
 860
 861 void *__copy_tls(unsigned char *mem)
 862 {
 863         pthread_t td;
 864         struct dso *p;
 865
 866         if (!tls_cnt) return mem;
 867
 868         void **dtv = (void *)mem;
 869         dtv[0] = (void *)tls_cnt;
 870
 871 #ifdef TLS_ABOVE_TP
 872         mem += sizeof(void *) * (tls_cnt+1);
 873         mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
 874         td = (pthread_t)mem;
 875         mem += sizeof(struct pthread);
 876
 877         for (p=head; p; p=p->next) {
 878                 if (!p->tls_id) continue;
 879                 dtv[p->tls_id] = mem + p->tls_offset;
 880                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 881         }
 882 #else
 883         mem += libc.tls_size - sizeof(struct pthread);
 884         mem -= (uintptr_t)mem & (tls_align-1);
 885         td = (pthread_t)mem;
 886
 887         for (p=head; p; p=p->next) {
 888                 if (!p->tls_id) continue;
 889                 dtv[p->tls_id] = mem - p->tls_offset;
 890                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 891         }
 892 #endif
 893         td->dtv = dtv;
 894         return td;
 895 }
 896
 897 void *__tls_get_addr(size_t *v)
 898 {
 899         pthread_t self = __pthread_self();
 900         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
 901                 return (char *)self->dtv[v[0]]+v[1];
 902
 903         /* Block signals to make accessing new TLS async-signal-safe */
 904         sigset_t set;
 905         pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
 906         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
 907                 pthread_sigmask(SIG_SETMASK, &set, 0);
 908                 return (char *)self->dtv[v[0]]+v[1];
 909         }
 910
 911         /* This is safe without any locks held because, if the caller
 912          * is able to request the Nth entry of the DTV, the DSO list
 913          * must be valid at least that far out and it was synchronized
 914          * at program startup or by an already-completed call to dlopen. */
 915         struct dso *p;
 916         for (p=head; p->tls_id != v[0]; p=p->next);
 917
 918         /* Get new DTV space from new DSO if needed */
 919         if (v[0] > (size_t)self->dtv[0]) {
 920                 void **newdtv = p->new_dtv +
 921                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
 922                 memcpy(newdtv, self->dtv,
 923                         ((size_t)self->dtv[0]+1) * sizeof(void *));
 924                 newdtv[0] = (void *)v[0];
 925                 self->dtv = newdtv;
 926         }
 927
 928         /* Get new TLS memory from new DSO */
 929         unsigned char *mem = p->new_tls +
 930                 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
 931         mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
 932         self->dtv[v[0]] = mem;
 933         memcpy(mem, p->tls_image, p->tls_len);
 934         pthread_sigmask(SIG_SETMASK, &set, 0);
 935         return mem + v[1];
 936 }
 937
 938 static void update_tls_size()
 939 {
 940         libc.tls_size = ALIGN(
 941                 (1+tls_cnt) * sizeof(void *) +
 942                 tls_offset +
 943                 sizeof(struct pthread) +
 944                 tls_align * 2,
 945         tls_align);
 946 }
 947
 948 void *__dynlink(int argc, char **argv)
 949 {
 950         size_t aux[AUX_CNT] = {0};
 951         size_t i;
 952         Phdr *phdr;
 953         Ehdr *ehdr;
 954         static struct dso builtin_dsos[3];
 955         struct dso *const app = builtin_dsos+0;
 956         struct dso *const lib = builtin_dsos+1;
 957         struct dso *const vdso = builtin_dsos+2;
 958         char *env_preload=0;
 959         size_t vdso_base;
 960         size_t *auxv;
 961         char **envp = argv+argc+1;
 962
 963         /* Find aux vector just past environ[] */
 964         for (i=argc+1; argv[i]; i++)
 965                 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
 966                         env_path = argv[i]+16;
 967                 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
 968                         env_preload = argv[i]+11;
 969         auxv = (void *)(argv+i+1);
 970
 971         decode_vec(auxv, aux, AUX_CNT);
 972
 973         /* Only trust user/env if kernel says we're not suid/sgid */
 974         if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
 975           || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
 976                 env_path = 0;
 977                 env_preload = 0;
 978                 libc.secure = 1;
 979         }
 980         libc.page_size = aux[AT_PAGESZ];
 981
 982         /* If the dynamic linker was invoked as a program itself, AT_BASE
 983          * will not be set. In that case, we assume the base address is
 984          * the start of the page containing the PHDRs; I don't know any
 985          * better approach... */
 986         if (!aux[AT_BASE]) {
 987                 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
 988                 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
 989         }
 990
 991         /* The dynamic linker load address is passed by the kernel
 992          * in the AUX vector, so this is easy. */
 993         lib->base = (void *)aux[AT_BASE];
 994         lib->name = lib->shortname = "libc.so";
 995         lib->global = 1;
 996         lib->kernel_mapped = 1;
 997         ehdr = (void *)lib->base;
 998         lib->phnum = ehdr->e_phnum;
 999         lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
1000         find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
1001         lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
1002                 ehdr->e_phnum, ehdr->e_phentsize));
1003         decode_dyn(lib);
1004
1005         if (aux[AT_PHDR]) {
1006                 size_t interp_off = 0;
1007                 size_t tls_image = 0;
1008                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1009                 app->phdr = phdr = (void *)aux[AT_PHDR];
1010                 app->phnum = aux[AT_PHNUM];
1011                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1012                         if (phdr->p_type == PT_PHDR)
1013                                 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1014                         else if (phdr->p_type == PT_INTERP)
1015                                 interp_off = (size_t)phdr->p_vaddr;
1016                         else if (phdr->p_type == PT_TLS) {
1017                                 tls_image = phdr->p_vaddr;
1018                                 app->tls_len = phdr->p_filesz;
1019                                 app->tls_size = phdr->p_memsz;
1020                                 app->tls_align = phdr->p_align;
1021                         }
1022                 }
1023                 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
1024                 if (interp_off) lib->name = (char *)app->base + interp_off;
1025                 if ((aux[0] & (1UL<<AT_EXECFN))
1026                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1027                         app->name = (char *)aux[AT_EXECFN];
1028                 else
1029                         app->name = argv[0];
1030                 app->kernel_mapped = 1;
1031                 app->dynv = (void *)(app->base + find_dyn(
1032                         (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
1033                 find_map_range((void *)aux[AT_PHDR],
1034                         aux[AT_PHNUM], aux[AT_PHENT], app);
1035         } else {
1036                 int fd;
1037                 char *ldname = argv[0];
1038                 size_t l = strlen(ldname);
1039                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1040                 *argv++ = (void *)-1;
1041                 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
1042                 if (!argv[0]) {
1043                         dprintf(2, "musl libc/dynamic program loader\n");
1044                         dprintf(2, "usage: %s pathname%s\n", ldname,
1045                                 ldd_mode ? "" : " [args]");
1046                         _exit(1);
1047                 }
1048                 fd = open(argv[0], O_RDONLY);
1049                 if (fd < 0) {
1050                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1051                         _exit(1);
1052                 }
1053                 runtime = 1;
1054                 ehdr = (void *)map_library(fd, app);
1055                 if (!ehdr) {
1056                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1057                         _exit(1);
1058                 }
1059                 runtime = 0;
1060                 close(fd);
1061                 lib->name = ldname;
1062                 app->name = argv[0];
1063                 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1064                 /* Find the name that would have been used for the dynamic
1065                  * linker had ldd not taken its place. */
1066                 if (ldd_mode) {
1067                         for (i=0; i<app->phnum; i++) {
1068                                 if (app->phdr[i].p_type == PT_INTERP)
1069                                         lib->name = (void *)(app->base
1070                                                 + app->phdr[i].p_vaddr);
1071                         }
1072                         dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1073                 }
1074         }
1075         if (app->tls_size) {
1076                 app->tls_id = tls_cnt = 1;
1077 #ifdef TLS_ABOVE_TP
1078                 app->tls_offset = 0;
1079                 tls_offset = app->tls_size
1080                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1081                         & (app->tls_align-1) );
1082 #else
1083                 tls_offset = app->tls_offset = app->tls_size
1084                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1085                         & (app->tls_align-1) );
1086 #endif
1087                 tls_align = MAXP2(tls_align, app->tls_align);
1088         }
1089         app->global = 1;
1090         decode_dyn(app);
1091
1092         /* Attach to vdso, if provided by the kernel */
1093         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1094                 ehdr = (void *)vdso_base;
1095                 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1096                 vdso->phnum = ehdr->e_phnum;
1097                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1098                         if (phdr->p_type == PT_DYNAMIC)
1099                                 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1100                         if (phdr->p_type == PT_LOAD)
1101                                 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1102                 }
1103                 vdso->name = "";
1104                 vdso->shortname = "linux-gate.so.1";
1105                 vdso->global = 1;
1106                 decode_dyn(vdso);
1107                 vdso->prev = lib;
1108                 lib->next = vdso;
1109         }
1110
1111         /* Initial dso chain consists only of the app. We temporarily
1112          * append the dynamic linker/libc so we can relocate it, then
1113          * restore the initial chain in preparation for loading third
1114          * party libraries (preload/needed). */
1115         head = tail = app;
1116         ldso = lib;
1117         app->next = lib;
1118         reloc_all(lib);
1119         app->next = 0;
1120
1121         /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1122
1123         /* Donate unused parts of app and library mapping to malloc */
1124         reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
1125         ehdr = (void *)lib->base;
1126         reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
1127                 ehdr->e_phentsize, ehdr->e_phnum);
1128
1129         /* Load preload/needed libraries, add their symbols to the global
1130          * namespace, and perform all remaining relocations. The main
1131          * program must be relocated LAST since it may contain copy
1132          * relocations which depend on libraries' relocations. */
1133         if (env_preload) load_preload(env_preload);
1134         load_deps(app);
1135         make_global(app);
1136
1137         reloc_all(app->next);
1138         reloc_all(app);
1139
1140         update_tls_size();
1141         if (tls_cnt) {
1142                 void *mem = mmap(0, libc.tls_size, PROT_READ|PROT_WRITE,
1143                         MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
1144                 if (mem==MAP_FAILED ||
1145                     !__install_initial_tls(__copy_tls(mem))) {
1146                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1147                                 argv[0], libc.tls_size);
1148                         _exit(127);
1149                 }
1150         }
1151
1152         if (ldso_fail) _exit(127);
1153         if (ldd_mode) _exit(0);
1154
1155         /* Switch to runtime mode: any further failures in the dynamic
1156          * linker are a reportable failure rather than a fatal startup
1157          * error. If the dynamic loader (dlopen) will not be used, free
1158          * all memory used by the dynamic linker. */
1159         runtime = 1;
1160
1161 #ifndef DYNAMIC_IS_RO
1162         for (i=0; app->dynv[i]; i+=2)
1163                 if (app->dynv[i]==DT_DEBUG)
1164                         app->dynv[i+1] = (size_t)&debug;
1165 #endif
1166         debug.ver = 1;
1167         debug.bp = _dl_debug_state;
1168         debug.head = head;
1169         debug.base = lib->base;
1170         debug.state = 0;
1171         _dl_debug_state();
1172
1173         if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
1174         __init_libc(envp, argv[0]);
1175         atexit(do_fini);
1176         errno = 0;
1177         do_init_fini(tail);
1178
1179         return (void *)aux[AT_ENTRY];
1180 }
1181
1182 void *dlopen(const char *file, int mode)
1183 {
1184         struct dso *volatile p, *orig_tail, *next;
1185         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1186         size_t i;
1187         int cs;
1188         jmp_buf jb;
1189
1190         if (!file) return head;
1191
1192         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1193         pthread_rwlock_wrlock(&lock);
1194         __inhibit_ptc();
1195
1196         p = 0;
1197         orig_tls_cnt = tls_cnt;
1198         orig_tls_offset = tls_offset;
1199         orig_tls_align = tls_align;
1200         orig_tail = tail;
1201         noload = mode & RTLD_NOLOAD;
1202
1203         rtld_fail = &jb;
1204         if (setjmp(*rtld_fail)) {
1205                 /* Clean up anything new that was (partially) loaded */
1206                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1207                         if (p->deps[i]->global < 0)
1208                                 p->deps[i]->global = 0;
1209                 for (p=orig_tail->next; p; p=next) {
1210                         next = p->next;
1211                         munmap(p->map, p->map_len);
1212                         free(p->deps);
1213                         free(p);
1214                 }
1215                 tls_cnt = orig_tls_cnt;
1216                 tls_offset = orig_tls_offset;
1217                 tls_align = orig_tls_align;
1218                 tail = orig_tail;
1219                 tail->next = 0;
1220                 p = 0;
1221                 errflag = 1;
1222                 goto end;
1223         } else p = load_library(file, head);
1224
1225         if (!p) {
1226                 snprintf(errbuf, sizeof errbuf, noload ?
1227                         "Library %s is not already loaded" :
1228                         "Error loading shared library %s: %m",
1229                         file);
1230                 errflag = 1;
1231                 goto end;
1232         }
1233
1234         /* First load handling */
1235         if (!p->deps) {
1236                 load_deps(p);
1237                 if (p->deps) for (i=0; p->deps[i]; i++)
1238                         if (!p->deps[i]->global)
1239                                 p->deps[i]->global = -1;
1240                 if (!p->global) p->global = -1;
1241                 reloc_all(p);
1242                 if (p->deps) for (i=0; p->deps[i]; i++)
1243                         if (p->deps[i]->global < 0)
1244                                 p->deps[i]->global = 0;
1245                 if (p->global < 0) p->global = 0;
1246         }
1247
1248         if (mode & RTLD_GLOBAL) {
1249                 if (p->deps) for (i=0; p->deps[i]; i++)
1250                         p->deps[i]->global = 1;
1251                 p->global = 1;
1252         }
1253
1254         update_tls_size();
1255
1256         if (ssp_used) __init_ssp(libc.auxv);
1257
1258         _dl_debug_state();
1259         orig_tail = tail;
1260 end:
1261         __release_ptc();
1262         if (p) gencnt++;
1263         pthread_rwlock_unlock(&lock);
1264         if (p) do_init_fini(orig_tail);
1265         pthread_setcancelstate(cs, 0);
1266         return p;
1267 }
1268
1269 static int invalid_dso_handle(void *h)
1270 {
1271         struct dso *p;
1272         for (p=head; p; p=p->next) if (h==p) return 0;
1273         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1274         errflag = 1;
1275         return 1;
1276 }
1277
1278 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1279 {
1280         size_t i;
1281         uint32_t h = 0, gh = 0;
1282         Sym *sym;
1283         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1284                 if (p == RTLD_DEFAULT) {
1285                         p = head;
1286                 } else if (p == RTLD_NEXT) {
1287                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1288                         if (!p) p=head;
1289                         p = p->next;
1290                 }
1291                 struct symdef def = find_sym(p, s, 0);
1292                 if (!def.sym) goto failed;
1293                 if ((def.sym->st_info&0xf) == STT_TLS)
1294                         return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1295                 return def.dso->base + def.sym->st_value;
1296         }
1297         if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1298                 return 0;
1299         if (p->ghashtab) {
1300                 gh = gnu_hash(s);
1301                 sym = gnu_lookup(s, gh, p);
1302         } else {
1303                 h = sysv_hash(s);
1304                 sym = sysv_lookup(s, h, p);
1305         }
1306         if (sym && (sym->st_info&0xf) == STT_TLS)
1307                 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1308         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1309                 return p->base + sym->st_value;
1310         if (p->deps) for (i=0; p->deps[i]; i++) {
1311                 if (p->deps[i]->ghashtab) {
1312                         if (!gh) gh = gnu_hash(s);
1313                         sym = gnu_lookup(s, gh, p->deps[i]);
1314                 } else {
1315                         if (!h) h = sysv_hash(s);
1316                         sym = sysv_lookup(s, h, p->deps[i]);
1317                 }
1318                 if (sym && (sym->st_info&0xf) == STT_TLS)
1319                         return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1320                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1321                         return p->deps[i]->base + sym->st_value;
1322         }
1323 failed:
1324         errflag = 1;
1325         snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1326         return 0;
1327 }
1328
1329 int __dladdr(void *addr, Dl_info *info)
1330 {
1331         struct dso *p;
1332         Sym *sym;
1333         uint32_t nsym;
1334         char *strings;
1335         size_t i;
1336         void *best = 0;
1337         char *bestname;
1338
1339         pthread_rwlock_rdlock(&lock);
1340         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1341         pthread_rwlock_unlock(&lock);
1342
1343         if (!p) return 0;
1344
1345         sym = p->syms;
1346         strings = p->strings;
1347         if (p->hashtab) {
1348                 nsym = p->hashtab[1];
1349         } else {
1350                 uint32_t *buckets;
1351                 uint32_t *hashval;
1352                 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1353                 sym += p->ghashtab[1];
1354                 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1355                         if (buckets[i] > nsym)
1356                                 nsym = buckets[i];
1357                 }
1358                 if (nsym) {
1359                         nsym -= p->ghashtab[1];
1360                         hashval = buckets + p->ghashtab[0] + nsym;
1361                         do nsym++;
1362                         while (!(*hashval++ & 1));
1363                 }
1364         }
1365
1366         for (; nsym; nsym--, sym++) {
1367                 if (sym->st_value
1368                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1369                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1370                         void *symaddr = p->base + sym->st_value;
1371                         if (symaddr > addr || symaddr < best)
1372                                 continue;
1373                         best = symaddr;
1374                         bestname = strings + sym->st_name;
1375                         if (addr == symaddr)
1376                                 break;
1377                 }
1378         }
1379
1380         if (!best) return 0;
1381
1382         info->dli_fname = p->name;
1383         info->dli_fbase = p->base;
1384         info->dli_sname = bestname;
1385         info->dli_saddr = best;
1386
1387         return 1;
1388 }
1389
1390 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1391 {
1392         void *res;
1393         pthread_rwlock_rdlock(&lock);
1394         res = do_dlsym(p, s, ra);
1395         pthread_rwlock_unlock(&lock);
1396         return res;
1397 }
1398
1399 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1400 {
1401         struct dso *current;
1402         struct dl_phdr_info info;
1403         int ret = 0;
1404         for(current = head; current;) {
1405                 info.dlpi_addr      = (uintptr_t)current->base;
1406                 info.dlpi_name      = current->name;
1407                 info.dlpi_phdr      = current->phdr;
1408                 info.dlpi_phnum     = current->phnum;
1409                 info.dlpi_adds      = gencnt;
1410                 info.dlpi_subs      = 0;
1411                 info.dlpi_tls_modid = current->tls_id;
1412                 info.dlpi_tls_data  = current->tls_image;
1413
1414                 ret = (callback)(&info, sizeof (info), data);
1415
1416                 if (ret != 0) break;
1417
1418                 pthread_rwlock_rdlock(&lock);
1419                 current = current->next;
1420                 pthread_rwlock_unlock(&lock);
1421         }
1422         return ret;
1423 }
1424 #else
1425 static int invalid_dso_handle(void *h)
1426 {
1427         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1428         errflag = 1;
1429         return 1;
1430 }
1431 void *dlopen(const char *file, int mode)
1432 {
1433         return 0;
1434 }
1435 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1436 {
1437         return 0;
1438 }
1439 int __dladdr (void *addr, Dl_info *info)
1440 {
1441         return 0;
1442 }
1443 #endif
1444
1445 int __dlinfo(void *dso, int req, void *res)
1446 {
1447         if (invalid_dso_handle(dso)) return -1;
1448         if (req != RTLD_DI_LINKMAP) {
1449                 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1450                 errflag = 1;
1451                 return -1;
1452         }
1453         *(struct link_map **)res = dso;
1454         return 0;
1455 }
1456
1457 char *dlerror()
1458 {
1459         if (!errflag) return 0;
1460         errflag = 0;
1461         return errbuf;
1462 }
1463
1464 int dlclose(void *p)
1465 {
1466         return invalid_dso_handle(p);
1467 }