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 <stdint.h>
  11 #include <fcntl.h>
  12 #include <sys/stat.h>
  13 #include <errno.h>
  14 #include <limits.h>
  15 #include <elf.h>
  16 #include <link.h>
  17 #include <setjmp.h>
  18 #include <pthread.h>
  19 #include <ctype.h>
  20 #include <dlfcn.h>
  21 #include "pthread_impl.h"
  22 #include "libc.h"
  23
  24 static int errflag;
  25 static char errbuf[128];
  26
  27 #ifdef SHARED
  28
  29 #if ULONG_MAX == 0xffffffff
  30 typedef Elf32_Ehdr Ehdr;
  31 typedef Elf32_Phdr Phdr;
  32 typedef Elf32_Sym Sym;
  33 #define R_TYPE(x) ((x)&255)
  34 #define R_SYM(x) ((x)>>8)
  35 #else
  36 typedef Elf64_Ehdr Ehdr;
  37 typedef Elf64_Phdr Phdr;
  38 typedef Elf64_Sym Sym;
  39 #define R_TYPE(x) ((x)&0xffffffff)
  40 #define R_SYM(x) ((x)>>32)
  41 #endif
  42
  43 #define MAXP2(a,b) (-(-(a)&-(b)))
  44 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
  45
  46 struct debug {
  47         int ver;
  48         void *head;
  49         void (*bp)(void);
  50         int state;
  51         void *base;
  52 };
  53
  54 struct dso {
  55         unsigned char *base;
  56         char *name;
  57         size_t *dynv;
  58         struct dso *next, *prev;
  59
  60         Phdr *phdr;
  61         int phnum;
  62         int refcnt;
  63         Sym *syms;
  64         uint32_t *hashtab;
  65         uint32_t *ghashtab;
  66         int16_t *versym;
  67         char *strings;
  68         unsigned char *map;
  69         size_t map_len;
  70         dev_t dev;
  71         ino_t ino;
  72         signed char global;
  73         char relocated;
  74         char constructed;
  75         char kernel_mapped;
  76         struct dso **deps, *needed_by;
  77         char *rpath_orig, *rpath;
  78         void *tls_image;
  79         size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
  80         void **new_dtv;
  81         unsigned char *new_tls;
  82         int new_dtv_idx, new_tls_idx;
  83         struct dso *fini_next;
  84         char *shortname;
  85         char buf[];
  86 };
  87
  88 struct symdef {
  89         Sym *sym;
  90         struct dso *dso;
  91 };
  92
  93 #include "reloc.h"
  94
  95 void __init_ssp(size_t *);
  96 void *__install_initial_tls(void *);
  97 void __init_libc(char **, char *);
  98
  99 static struct dso *head, *tail, *ldso, *fini_head;
 100 static char *env_path, *sys_path;
 101 static unsigned long long gencnt;
 102 static int ssp_used;
 103 static int runtime;
 104 static int ldd_mode;
 105 static int ldso_fail;
 106 static int noload;
 107 static jmp_buf *rtld_fail;
 108 static pthread_rwlock_t lock;
 109 static struct debug debug;
 110 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
 111 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 112
 113 struct debug *_dl_debug_addr = &debug;
 114
 115 #define AUX_CNT 38
 116 #define DYN_CNT 34
 117
 118 static void decode_vec(size_t *v, size_t *a, size_t cnt)
 119 {
 120         memset(a, 0, cnt*sizeof(size_t));
 121         for (; v[0]; v+=2) if (v[0]<cnt) {
 122                 a[0] |= 1ULL<<v[0];
 123                 a[v[0]] = v[1];
 124         }
 125 }
 126
 127 static int search_vec(size_t *v, size_t *r, size_t key)
 128 {
 129         for (; v[0]!=key; v+=2)
 130                 if (!v[0]) return 0;
 131         *r = v[1];
 132         return 1;
 133 }
 134
 135 static uint32_t sysv_hash(const char *s0)
 136 {
 137         const unsigned char *s = (void *)s0;
 138         uint_fast32_t h = 0;
 139         while (*s) {
 140                 h = 16*h + *s++;
 141                 h ^= h>>24 & 0xf0;
 142         }
 143         return h & 0xfffffff;
 144 }
 145
 146 static uint32_t gnu_hash(const char *s0)
 147 {
 148         const unsigned char *s = (void *)s0;
 149         uint_fast32_t h = 5381;
 150         for (; *s; s++)
 151                 h = h*33 + *s;
 152         return h;
 153 }
 154
 155 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
 156 {
 157         size_t i;
 158         Sym *syms = dso->syms;
 159         uint32_t *hashtab = dso->hashtab;
 160         char *strings = dso->strings;
 161         for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
 162                 if ((!dso->versym || dso->versym[i] >= 0)
 163                     && (!strcmp(s, strings+syms[i].st_name)))
 164                         return syms+i;
 165         }
 166         return 0;
 167 }
 168
 169 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
 170 {
 171         Sym *syms = dso->syms;
 172         char *strings = dso->strings;
 173         uint32_t *hashtab = dso->ghashtab;
 174         uint32_t nbuckets = hashtab[0];
 175         uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
 176         uint32_t h2;
 177         uint32_t *hashval;
 178         uint32_t i = buckets[h1 % nbuckets];
 179
 180         if (!i) return 0;
 181
 182         hashval = buckets + nbuckets + (i - hashtab[1]);
 183
 184         for (h1 |= 1; ; i++) {
 185                 h2 = *hashval++;
 186                 if ((!dso->versym || dso->versym[i] >= 0)
 187                     && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
 188                         return syms+i;
 189                 if (h2 & 1) break;
 190         }
 191
 192         return 0;
 193 }
 194
 195 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
 196 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
 197
 198 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
 199 {
 200         uint32_t h = 0, gh = 0;
 201         struct symdef def = {0};
 202         if (dso->ghashtab) {
 203                 gh = gnu_hash(s);
 204                 if (gh == 0x1f4039c9 && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 205         } else {
 206                 h = sysv_hash(s);
 207                 if (h == 0x595a4cc && !strcmp(s, "__stack_chk_fail")) ssp_used = 1;
 208         }
 209         for (; dso; dso=dso->next) {
 210                 Sym *sym;
 211                 if (!dso->global) continue;
 212                 if (dso->ghashtab) {
 213                         if (!gh) gh = gnu_hash(s);
 214                         sym = gnu_lookup(s, gh, dso);
 215                 } else {
 216                         if (!h) h = sysv_hash(s);
 217                         sym = sysv_lookup(s, h, dso);
 218                 }
 219                 if (!sym) continue;
 220                 if (!sym->st_shndx)
 221                         if (need_def || (sym->st_info&0xf) == STT_TLS)
 222                                 continue;
 223                 if (!sym->st_value)
 224                         if ((sym->st_info&0xf) != STT_TLS)
 225                                 continue;
 226                 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
 227                 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
 228
 229                 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
 230                 def.sym = sym;
 231                 def.dso = dso;
 232                 if (sym->st_info>>4 == STB_GLOBAL) break;
 233         }
 234         return def;
 235 }
 236
 237 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
 238 {
 239         unsigned char *base = dso->base;
 240         Sym *syms = dso->syms;
 241         char *strings = dso->strings;
 242         Sym *sym;
 243         const char *name;
 244         void *ctx;
 245         int type;
 246         int sym_index;
 247         struct symdef def;
 248
 249         for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
 250                 type = R_TYPE(rel[1]);
 251                 sym_index = R_SYM(rel[1]);
 252                 if (sym_index) {
 253                         sym = syms + sym_index;
 254                         name = strings + sym->st_name;
 255                         ctx = IS_COPY(type) ? head->next : head;
 256                         def = find_sym(ctx, name, IS_PLT(type));
 257                         if (!def.sym && sym->st_info>>4 != STB_WEAK) {
 258                                 snprintf(errbuf, sizeof errbuf,
 259                                         "Error relocating %s: %s: symbol not found",
 260                                         dso->name, name);
 261                                 if (runtime) longjmp(*rtld_fail, 1);
 262                                 dprintf(2, "%s\n", errbuf);
 263                                 ldso_fail = 1;
 264                                 continue;
 265                         }
 266                 } else {
 267                         sym = 0;
 268                         def.sym = 0;
 269                         def.dso = 0;
 270                 }
 271                 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
 272                         stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
 273                         def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
 274         }
 275 }
 276
 277 /* A huge hack: to make up for the wastefulness of shared libraries
 278  * needing at least a page of dirty memory even if they have no global
 279  * data, we reclaim the gaps at the beginning and end of writable maps
 280  * and "donate" them to the heap by setting up minimal malloc
 281  * structures and then freeing them. */
 282
 283 static void reclaim(unsigned char *base, size_t start, size_t end)
 284 {
 285         size_t *a, *z;
 286         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 287         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 288         if (start>end || end-start < 4*sizeof(size_t)) return;
 289         a = (size_t *)(base + start);
 290         z = (size_t *)(base + end);
 291         a[-2] = 1;
 292         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 293         z[1] = 1;
 294         free(a);
 295 }
 296
 297 static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phcnt)
 298 {
 299         for (; phcnt--; ph=(void *)((char *)ph+phent)) {
 300                 if (ph->p_type!=PT_LOAD) continue;
 301                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 302                 reclaim(base, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 303                 reclaim(base, ph->p_vaddr+ph->p_memsz,
 304                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 305         }
 306 }
 307
 308 static void *map_library(int fd, struct dso *dso)
 309 {
 310         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 311         void *allocated_buf=0;
 312         size_t phsize;
 313         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 314         size_t this_min, this_max;
 315         off_t off_start;
 316         Ehdr *eh;
 317         Phdr *ph, *ph0;
 318         unsigned prot;
 319         unsigned char *map=MAP_FAILED, *base;
 320         size_t dyn=0;
 321         size_t tls_image=0;
 322         size_t i;
 323
 324         ssize_t l = read(fd, buf, sizeof buf);
 325         eh = buf;
 326         if (l<0) return 0;
 327         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 328                 goto noexec;
 329         phsize = eh->e_phentsize * eh->e_phnum;
 330         if (phsize > sizeof buf - sizeof *eh) {
 331                 allocated_buf = malloc(phsize);
 332                 if (!allocated_buf) return 0;
 333                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 334                 if (l < 0) goto error;
 335                 if (l != phsize) goto noexec;
 336                 ph = ph0 = allocated_buf;
 337         } else if (eh->e_phoff + phsize > l) {
 338                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 339                 if (l < 0) goto error;
 340                 if (l != phsize) goto noexec;
 341                 ph = ph0 = (void *)(buf + 1);
 342         } else {
 343                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 344         }
 345         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 346                 if (ph->p_type == PT_DYNAMIC)
 347                         dyn = ph->p_vaddr;
 348                 if (ph->p_type == PT_TLS) {
 349                         tls_image = ph->p_vaddr;
 350                         dso->tls_align = ph->p_align;
 351                         dso->tls_len = ph->p_filesz;
 352                         dso->tls_size = ph->p_memsz;
 353                 }
 354                 if (ph->p_type != PT_LOAD) continue;
 355                 if (ph->p_vaddr < addr_min) {
 356                         addr_min = ph->p_vaddr;
 357                         off_start = ph->p_offset;
 358                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 359                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 360                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 361                 }
 362                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 363                         addr_max = ph->p_vaddr+ph->p_memsz;
 364                 }
 365         }
 366         if (!dyn) goto noexec;
 367         addr_max += PAGE_SIZE-1;
 368         addr_max &= -PAGE_SIZE;
 369         addr_min &= -PAGE_SIZE;
 370         off_start &= -PAGE_SIZE;
 371         map_len = addr_max - addr_min + off_start;
 372         /* The first time, we map too much, possibly even more than
 373          * the length of the file. This is okay because we will not
 374          * use the invalid part; we just need to reserve the right
 375          * amount of virtual address space to map over later. */
 376         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 377         if (map==MAP_FAILED) goto error;
 378         /* If the loaded file is not relocatable and the requested address is
 379          * not available, then the load operation must fail. */
 380         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 381                 errno = EBUSY;
 382                 goto error;
 383         }
 384         base = map - addr_min;
 385         dso->phdr = 0;
 386         dso->phnum = 0;
 387         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 388                 if (ph->p_type != PT_LOAD) continue;
 389                 /* Check if the programs headers are in this load segment, and
 390                  * if so, record the address for use by dl_iterate_phdr. */
 391                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 392                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 393                         dso->phdr = (void *)(base + ph->p_vaddr
 394                                 + (eh->e_phoff-ph->p_offset));
 395                         dso->phnum = eh->e_phnum;
 396                 }
 397                 /* Reuse the existing mapping for the lowest-address LOAD */
 398                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 399                 this_min = ph->p_vaddr & -PAGE_SIZE;
 400                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 401                 off_start = ph->p_offset & -PAGE_SIZE;
 402                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 403                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 404                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 405                 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 406                         goto error;
 407                 if (ph->p_memsz > ph->p_filesz) {
 408                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 409                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 410                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 411                         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)
 412                                 goto error;
 413                 }
 414         }
 415         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 416                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 417                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
 418                                 goto error;
 419                         break;
 420                 }
 421         if (!runtime) reclaim_gaps(base, ph0, eh->e_phentsize, eh->e_phnum);
 422         dso->map = map;
 423         dso->map_len = map_len;
 424         dso->base = base;
 425         dso->dynv = (void *)(base+dyn);
 426         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 427         free(allocated_buf);
 428         return map;
 429 noexec:
 430         errno = ENOEXEC;
 431 error:
 432         if (map!=MAP_FAILED) munmap(map, map_len);
 433         free(allocated_buf);
 434         return 0;
 435 }
 436
 437 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 438 {
 439         size_t l;
 440         int fd;
 441         for (;;) {
 442                 s += strspn(s, ":\n");
 443                 l = strcspn(s, ":\n");
 444                 if (l-1 >= INT_MAX) return -1;
 445                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
 446                         continue;
 447                 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 448                 s += l;
 449         }
 450 }
 451
 452 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 453 {
 454         size_t n, l;
 455         const char *s, *t, *origin;
 456         char *d;
 457         if (p->rpath) return 0;
 458         if (!p->rpath_orig) return -1;
 459         if (!strchr(p->rpath_orig, '$')) {
 460                 p->rpath = p->rpath_orig;
 461                 return 0;
 462         }
 463         n = 0;
 464         s = p->rpath_orig;
 465         while ((t=strchr(s, '$'))) {
 466                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 467                         return -1;
 468                 s = t+1;
 469                 n++;
 470         }
 471         if (n > SSIZE_MAX/PATH_MAX) return -1;
 472
 473         if (p->kernel_mapped) {
 474                 /* $ORIGIN searches cannot be performed for the main program
 475                  * when it is suid/sgid/AT_SECURE. This is because the
 476                  * pathname is under the control of the caller of execve.
 477                  * For libraries, however, $ORIGIN can be processed safely
 478                  * since the library's pathname came from a trusted source
 479                  * (either system paths or a call to dlopen). */
 480                 if (libc.secure)
 481                         return -1;
 482                 l = readlink("/proc/self/exe", buf, buf_size);
 483                 if (l >= buf_size)
 484                         return -1;
 485                 buf[l] = 0;
 486                 origin = buf;
 487         } else {
 488                 origin = p->name;
 489         }
 490         t = strrchr(origin, '/');
 491         l = t ? t-origin : 0;
 492         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 493         if (!p->rpath) return -1;
 494
 495         d = p->rpath;
 496         s = p->rpath_orig;
 497         while ((t=strchr(s, '$'))) {
 498                 memcpy(d, s, t-s);
 499                 d += t-s;
 500                 memcpy(d, origin, l);
 501                 d += l;
 502                 /* It was determined previously that the '$' is followed
 503                  * either by "ORIGIN" or "{ORIGIN}". */
 504                 s = t + 7 + 2*(t[1]=='{');
 505         }
 506         strcpy(d, s);
 507         return 0;
 508 }
 509
 510 static void decode_dyn(struct dso *p)
 511 {
 512         size_t dyn[DYN_CNT] = {0};
 513         decode_vec(p->dynv, dyn, DYN_CNT);
 514         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 515         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 516         if (dyn[0]&(1<<DT_HASH))
 517                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 518         if (dyn[0]&(1<<DT_RPATH))
 519                 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
 520         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 521                 p->ghashtab = (void *)(p->base + *dyn);
 522         if (search_vec(p->dynv, dyn, DT_VERSYM))
 523                 p->versym = (void *)(p->base + *dyn);
 524 }
 525
 526 static struct dso *load_library(const char *name, struct dso *needed_by)
 527 {
 528         char buf[2*NAME_MAX+2];
 529         const char *pathname;
 530         unsigned char *map;
 531         struct dso *p, temp_dso = {0};
 532         int fd;
 533         struct stat st;
 534         size_t alloc_size;
 535         int n_th = 0;
 536         int is_self = 0;
 537
 538         /* Catch and block attempts to reload the implementation itself */
 539         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 540                 static const char *rp, reserved[] =
 541                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 542                 char *z = strchr(name, '.');
 543                 if (z) {
 544                         size_t l = z-name;
 545                         for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 546                         if (*rp) {
 547                                 if (ldd_mode) {
 548                                         /* Track which names have been resolved
 549                                          * and only report each one once. */
 550                                         static unsigned reported;
 551                                         unsigned mask = 1U<<(rp-reserved);
 552                                         if (!(reported & mask)) {
 553                                                 reported |= mask;
 554                                                 dprintf(1, "\t%s => %s (%p)\n",
 555                                                         name, ldso->name,
 556                                                         ldso->base);
 557                                         }
 558                                 }
 559                                 is_self = 1;
 560                         }
 561                 }
 562         }
 563         if (!strcmp(name, ldso->name)) is_self = 1;
 564         if (is_self) {
 565                 if (!ldso->prev) {
 566                         tail->next = ldso;
 567                         ldso->prev = tail;
 568                         tail = ldso->next ? ldso->next : ldso;
 569                 }
 570                 return ldso;
 571         }
 572         if (strchr(name, '/')) {
 573                 pathname = name;
 574                 fd = open(name, O_RDONLY|O_CLOEXEC);
 575         } else {
 576                 /* Search for the name to see if it's already loaded */
 577                 for (p=head->next; p; p=p->next) {
 578                         if (p->shortname && !strcmp(p->shortname, name)) {
 579                                 p->refcnt++;
 580                                 return p;
 581                         }
 582                 }
 583                 if (strlen(name) > NAME_MAX) return 0;
 584                 fd = -1;
 585                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 586                 for (p=needed_by; fd < 0 && p; p=p->needed_by)
 587                         if (!fixup_rpath(p, buf, sizeof buf))
 588                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 589                 if (fd < 0) {
 590                         if (!sys_path) {
 591                                 char *prefix = 0;
 592                                 size_t prefix_len;
 593                                 if (ldso->name[0]=='/') {
 594                                         char *s, *t, *z;
 595                                         for (s=t=z=ldso->name; *s; s++)
 596                                                 if (*s=='/') z=t, t=s;
 597                                         prefix_len = z-ldso->name;
 598                                         if (prefix_len < PATH_MAX)
 599                                                 prefix = ldso->name;
 600                                 }
 601                                 if (!prefix) {
 602                                         prefix = "";
 603                                         prefix_len = 0;
 604                                 }
 605                                 char etc_ldso_path[prefix_len + 1
 606                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
 607                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
 608                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
 609                                         (int)prefix_len, prefix);
 610                                 FILE *f = fopen(etc_ldso_path, "rbe");
 611                                 if (f) {
 612                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
 613                                                 free(sys_path);
 614                                                 sys_path = "";
 615                                         }
 616                                         fclose(f);
 617                                 } else if (errno != ENOENT) {
 618                                         sys_path = "";
 619                                 }
 620                         }
 621                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
 622                         fd = path_open(name, sys_path, buf, sizeof buf);
 623                 }
 624                 pathname = buf;
 625         }
 626         if (fd < 0) return 0;
 627         if (fstat(fd, &st) < 0) {
 628                 close(fd);
 629                 return 0;
 630         }
 631         for (p=head->next; p; p=p->next) {
 632                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 633                         /* If this library was previously loaded with a
 634                          * pathname but a search found the same inode,
 635                          * setup its shortname so it can be found by name. */
 636                         if (!p->shortname && pathname != name)
 637                                 p->shortname = strrchr(p->name, '/')+1;
 638                         close(fd);
 639                         p->refcnt++;
 640                         return p;
 641                 }
 642         }
 643         map = noload ? 0 : map_library(fd, &temp_dso);
 644         close(fd);
 645         if (!map) return 0;
 646
 647         /* Allocate storage for the new DSO. When there is TLS, this
 648          * storage must include a reservation for all pre-existing
 649          * threads to obtain copies of both the new TLS, and an
 650          * extended DTV capable of storing an additional slot for
 651          * the newly-loaded DSO. */
 652         alloc_size = sizeof *p + strlen(pathname) + 1;
 653         if (runtime && temp_dso.tls_image) {
 654                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 655                         + sizeof(void *) * (tls_cnt+3);
 656                 n_th = libc.threads_minus_1 + 1;
 657                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 658                 else alloc_size += n_th * per_th;
 659         }
 660         p = calloc(1, alloc_size);
 661         if (!p) {
 662                 munmap(map, temp_dso.map_len);
 663                 return 0;
 664         }
 665         memcpy(p, &temp_dso, sizeof temp_dso);
 666         decode_dyn(p);
 667         p->dev = st.st_dev;
 668         p->ino = st.st_ino;
 669         p->refcnt = 1;
 670         p->needed_by = needed_by;
 671         p->name = p->buf;
 672         strcpy(p->name, pathname);
 673         /* Add a shortname only if name arg was not an explicit pathname. */
 674         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 675         if (p->tls_image) {
 676                 if (runtime && !__pthread_self_init()) {
 677                         munmap(map, p->map_len);
 678                         free(p);
 679                         return 0;
 680                 }
 681                 p->tls_id = ++tls_cnt;
 682                 tls_align = MAXP2(tls_align, p->tls_align);
 683 #ifdef TLS_ABOVE_TP
 684                 p->tls_offset = tls_offset + ( (tls_align-1) &
 685                         -(tls_offset + (uintptr_t)p->tls_image) );
 686                 tls_offset += p->tls_size;
 687 #else
 688                 tls_offset += p->tls_size + p->tls_align - 1;
 689                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 690                         & (p->tls_align-1);
 691                 p->tls_offset = tls_offset;
 692 #endif
 693                 p->new_dtv = (void *)(-sizeof(size_t) &
 694                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 695                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 696         }
 697
 698         tail->next = p;
 699         p->prev = tail;
 700         tail = p;
 701
 702         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 703
 704         return p;
 705 }
 706
 707 static void load_deps(struct dso *p)
 708 {
 709         size_t i, ndeps=0;
 710         struct dso ***deps = &p->deps, **tmp, *dep;
 711         for (; p; p=p->next) {
 712                 for (i=0; p->dynv[i]; i+=2) {
 713                         if (p->dynv[i] != DT_NEEDED) continue;
 714                         dep = load_library(p->strings + p->dynv[i+1], p);
 715                         if (!dep) {
 716                                 snprintf(errbuf, sizeof errbuf,
 717                                         "Error loading shared library %s: %m (needed by %s)",
 718                                         p->strings + p->dynv[i+1], p->name);
 719                                 if (runtime) longjmp(*rtld_fail, 1);
 720                                 dprintf(2, "%s\n", errbuf);
 721                                 ldso_fail = 1;
 722                                 continue;
 723                         }
 724                         if (runtime) {
 725                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 726                                 if (!tmp) longjmp(*rtld_fail, 1);
 727                                 tmp[ndeps++] = dep;
 728                                 tmp[ndeps] = 0;
 729                                 *deps = tmp;
 730                         }
 731                 }
 732         }
 733 }
 734
 735 static void load_preload(char *s)
 736 {
 737         int tmp;
 738         char *z;
 739         for (z=s; *z; s=z) {
 740                 for (   ; *s && isspace(*s); s++);
 741                 for (z=s; *z && !isspace(*z); z++);
 742                 tmp = *z;
 743                 *z = 0;
 744                 load_library(s, 0);
 745                 *z = tmp;
 746         }
 747 }
 748
 749 static void make_global(struct dso *p)
 750 {
 751         for (; p; p=p->next) p->global = 1;
 752 }
 753
 754 static void reloc_all(struct dso *p)
 755 {
 756         size_t dyn[DYN_CNT] = {0};
 757         for (; p; p=p->next) {
 758                 if (p->relocated) continue;
 759                 decode_vec(p->dynv, dyn, DYN_CNT);
 760 #ifdef NEED_ARCH_RELOCS
 761                 do_arch_relocs(p, head);
 762 #endif
 763                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 764                         2+(dyn[DT_PLTREL]==DT_RELA));
 765                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 766                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 767                 p->relocated = 1;
 768         }
 769 }
 770
 771 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
 772 {
 773         for (; cnt--; ph = (void *)((char *)ph + stride))
 774                 if (ph->p_type == PT_DYNAMIC)
 775                         return ph->p_vaddr;
 776         return 0;
 777 }
 778
 779 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
 780 {
 781         size_t min_addr = -1, max_addr = 0;
 782         for (; cnt--; ph = (void *)((char *)ph + stride)) {
 783                 if (ph->p_type != PT_LOAD) continue;
 784                 if (ph->p_vaddr < min_addr)
 785                         min_addr = ph->p_vaddr;
 786                 if (ph->p_vaddr+ph->p_memsz > max_addr)
 787                         max_addr = ph->p_vaddr+ph->p_memsz;
 788         }
 789         min_addr &= -PAGE_SIZE;
 790         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
 791         p->map = p->base + min_addr;
 792         p->map_len = max_addr - min_addr;
 793 }
 794
 795 static void do_fini()
 796 {
 797         struct dso *p;
 798         size_t dyn[DYN_CNT] = {0};
 799         for (p=fini_head; p; p=p->fini_next) {
 800                 if (!p->constructed) continue;
 801                 decode_vec(p->dynv, dyn, DYN_CNT);
 802                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
 803                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
 804                         size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
 805                         while (n--) ((void (*)(void))*--fn)();
 806                 }
 807 #ifndef NO_LEGACY_INITFINI
 808                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
 809                         ((void (*)(void))(p->base + dyn[DT_FINI]))();
 810 #endif
 811         }
 812 }
 813
 814 static void do_init_fini(struct dso *p)
 815 {
 816         size_t dyn[DYN_CNT] = {0};
 817         int need_locking = libc.threads_minus_1;
 818         /* Allow recursive calls that arise when a library calls
 819          * dlopen from one of its constructors, but block any
 820          * other threads until all ctors have finished. */
 821         if (need_locking) pthread_mutex_lock(&init_fini_lock);
 822         for (; p; p=p->prev) {
 823                 if (p->constructed) continue;
 824                 p->constructed = 1;
 825                 decode_vec(p->dynv, dyn, DYN_CNT);
 826                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
 827                         p->fini_next = fini_head;
 828                         fini_head = p;
 829                 }
 830 #ifndef NO_LEGACY_INITFINI
 831                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
 832                         ((void (*)(void))(p->base + dyn[DT_INIT]))();
 833 #endif
 834                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
 835                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
 836                         size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
 837                         while (n--) ((void (*)(void))*fn++)();
 838                 }
 839                 if (!need_locking && libc.threads_minus_1) {
 840                         need_locking = 1;
 841                         pthread_mutex_lock(&init_fini_lock);
 842                 }
 843         }
 844         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
 845 }
 846
 847 void _dl_debug_state(void)
 848 {
 849 }
 850
 851 void __reset_tls()
 852 {
 853         pthread_t self = __pthread_self();
 854         struct dso *p;
 855         for (p=head; p; p=p->next) {
 856                 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
 857                 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
 858                 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
 859                         p->tls_size - p->tls_len);
 860                 if (p->tls_id == (size_t)self->dtv[0]) break;
 861         }
 862 }
 863
 864 void *__copy_tls(unsigned char *mem)
 865 {
 866         pthread_t td;
 867         struct dso *p;
 868
 869         if (!tls_cnt) return mem;
 870
 871         void **dtv = (void *)mem;
 872         dtv[0] = (void *)tls_cnt;
 873
 874 #ifdef TLS_ABOVE_TP
 875         mem += sizeof(void *) * (tls_cnt+1);
 876         mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
 877         td = (pthread_t)mem;
 878         mem += sizeof(struct pthread);
 879
 880         for (p=head; p; p=p->next) {
 881                 if (!p->tls_id) continue;
 882                 dtv[p->tls_id] = mem + p->tls_offset;
 883                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 884         }
 885 #else
 886         mem += libc.tls_size - sizeof(struct pthread);
 887         mem -= (uintptr_t)mem & (tls_align-1);
 888         td = (pthread_t)mem;
 889
 890         for (p=head; p; p=p->next) {
 891                 if (!p->tls_id) continue;
 892                 dtv[p->tls_id] = mem - p->tls_offset;
 893                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 894         }
 895 #endif
 896         td->dtv = dtv;
 897         return td;
 898 }
 899
 900 void *__tls_get_addr(size_t *v)
 901 {
 902         pthread_t self = __pthread_self();
 903         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
 904                 return (char *)self->dtv[v[0]]+v[1];
 905
 906         /* Block signals to make accessing new TLS async-signal-safe */
 907         sigset_t set;
 908         pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
 909         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
 910                 pthread_sigmask(SIG_SETMASK, &set, 0);
 911                 return (char *)self->dtv[v[0]]+v[1];
 912         }
 913
 914         /* This is safe without any locks held because, if the caller
 915          * is able to request the Nth entry of the DTV, the DSO list
 916          * must be valid at least that far out and it was synchronized
 917          * at program startup or by an already-completed call to dlopen. */
 918         struct dso *p;
 919         for (p=head; p->tls_id != v[0]; p=p->next);
 920
 921         /* Get new DTV space from new DSO if needed */
 922         if (v[0] > (size_t)self->dtv[0]) {
 923                 void **newdtv = p->new_dtv +
 924                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
 925                 memcpy(newdtv, self->dtv,
 926                         ((size_t)self->dtv[0]+1) * sizeof(void *));
 927                 newdtv[0] = (void *)v[0];
 928                 self->dtv = newdtv;
 929         }
 930
 931         /* Get new TLS memory from new DSO */
 932         unsigned char *mem = p->new_tls +
 933                 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
 934         mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
 935         self->dtv[v[0]] = mem;
 936         memcpy(mem, p->tls_image, p->tls_len);
 937         pthread_sigmask(SIG_SETMASK, &set, 0);
 938         return mem + v[1];
 939 }
 940
 941 static void update_tls_size()
 942 {
 943         libc.tls_size = ALIGN(
 944                 (1+tls_cnt) * sizeof(void *) +
 945                 tls_offset +
 946                 sizeof(struct pthread) +
 947                 tls_align * 2,
 948         tls_align);
 949 }
 950
 951 void *__dynlink(int argc, char **argv)
 952 {
 953         size_t aux[AUX_CNT] = {0};
 954         size_t i;
 955         Phdr *phdr;
 956         Ehdr *ehdr;
 957         static struct dso builtin_dsos[3];
 958         struct dso *const app = builtin_dsos+0;
 959         struct dso *const lib = builtin_dsos+1;
 960         struct dso *const vdso = builtin_dsos+2;
 961         char *env_preload=0;
 962         size_t vdso_base;
 963         size_t *auxv;
 964         char **envp = argv+argc+1;
 965
 966         /* Find aux vector just past environ[] */
 967         for (i=argc+1; argv[i]; i++)
 968                 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
 969                         env_path = argv[i]+16;
 970                 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
 971                         env_preload = argv[i]+11;
 972         auxv = (void *)(argv+i+1);
 973
 974         decode_vec(auxv, aux, AUX_CNT);
 975
 976         /* Only trust user/env if kernel says we're not suid/sgid */
 977         if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
 978           || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
 979                 env_path = 0;
 980                 env_preload = 0;
 981                 libc.secure = 1;
 982         }
 983         libc.page_size = aux[AT_PAGESZ];
 984
 985         /* If the dynamic linker was invoked as a program itself, AT_BASE
 986          * will not be set. In that case, we assume the base address is
 987          * the start of the page containing the PHDRs; I don't know any
 988          * better approach... */
 989         if (!aux[AT_BASE]) {
 990                 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
 991                 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
 992         }
 993
 994         /* The dynamic linker load address is passed by the kernel
 995          * in the AUX vector, so this is easy. */
 996         lib->base = (void *)aux[AT_BASE];
 997         lib->name = lib->shortname = "libc.so";
 998         lib->global = 1;
 999         lib->kernel_mapped = 1;
1000         ehdr = (void *)lib->base;
1001         lib->phnum = ehdr->e_phnum;
1002         lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
1003         find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
1004         lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
1005                 ehdr->e_phnum, ehdr->e_phentsize));
1006         decode_dyn(lib);
1007
1008         if (aux[AT_PHDR]) {
1009                 size_t interp_off = 0;
1010                 size_t tls_image = 0;
1011                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1012                 app->phdr = phdr = (void *)aux[AT_PHDR];
1013                 app->phnum = aux[AT_PHNUM];
1014                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1015                         if (phdr->p_type == PT_PHDR)
1016                                 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1017                         else if (phdr->p_type == PT_INTERP)
1018                                 interp_off = (size_t)phdr->p_vaddr;
1019                         else if (phdr->p_type == PT_TLS) {
1020                                 tls_image = phdr->p_vaddr;
1021                                 app->tls_len = phdr->p_filesz;
1022                                 app->tls_size = phdr->p_memsz;
1023                                 app->tls_align = phdr->p_align;
1024                         }
1025                 }
1026                 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
1027                 if (interp_off) lib->name = (char *)app->base + interp_off;
1028                 if ((aux[0] & (1UL<<AT_EXECFN))
1029                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1030                         app->name = (char *)aux[AT_EXECFN];
1031                 else
1032                         app->name = argv[0];
1033                 app->kernel_mapped = 1;
1034                 app->dynv = (void *)(app->base + find_dyn(
1035                         (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
1036                 find_map_range((void *)aux[AT_PHDR],
1037                         aux[AT_PHNUM], aux[AT_PHENT], app);
1038         } else {
1039                 int fd;
1040                 char *ldname = argv[0];
1041                 size_t l = strlen(ldname);
1042                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1043                 *argv++ = (void *)-1;
1044                 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
1045                 if (!argv[0]) {
1046                         dprintf(2, "musl libc/dynamic program loader\n");
1047                         dprintf(2, "usage: %s pathname%s\n", ldname,
1048                                 ldd_mode ? "" : " [args]");
1049                         _exit(1);
1050                 }
1051                 fd = open(argv[0], O_RDONLY);
1052                 if (fd < 0) {
1053                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1054                         _exit(1);
1055                 }
1056                 runtime = 1;
1057                 ehdr = (void *)map_library(fd, app);
1058                 if (!ehdr) {
1059                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1060                         _exit(1);
1061                 }
1062                 runtime = 0;
1063                 close(fd);
1064                 lib->name = ldname;
1065                 app->name = argv[0];
1066                 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1067                 /* Find the name that would have been used for the dynamic
1068                  * linker had ldd not taken its place. */
1069                 if (ldd_mode) {
1070                         for (i=0; i<app->phnum; i++) {
1071                                 if (app->phdr[i].p_type == PT_INTERP)
1072                                         lib->name = (void *)(app->base
1073                                                 + app->phdr[i].p_vaddr);
1074                         }
1075                         dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1076                 }
1077         }
1078         if (app->tls_size) {
1079                 app->tls_id = tls_cnt = 1;
1080 #ifdef TLS_ABOVE_TP
1081                 app->tls_offset = 0;
1082                 tls_offset = app->tls_size
1083                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1084                         & (app->tls_align-1) );
1085 #else
1086                 tls_offset = app->tls_offset = app->tls_size
1087                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1088                         & (app->tls_align-1) );
1089 #endif
1090                 tls_align = MAXP2(tls_align, app->tls_align);
1091         }
1092         app->global = 1;
1093         decode_dyn(app);
1094
1095         /* Attach to vdso, if provided by the kernel */
1096         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1097                 ehdr = (void *)vdso_base;
1098                 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1099                 vdso->phnum = ehdr->e_phnum;
1100                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1101                         if (phdr->p_type == PT_DYNAMIC)
1102                                 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1103                         if (phdr->p_type == PT_LOAD)
1104                                 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1105                 }
1106                 vdso->name = "";
1107                 vdso->shortname = "linux-gate.so.1";
1108                 vdso->global = 1;
1109                 decode_dyn(vdso);
1110                 vdso->prev = lib;
1111                 lib->next = vdso;
1112         }
1113
1114         /* Initial dso chain consists only of the app. We temporarily
1115          * append the dynamic linker/libc so we can relocate it, then
1116          * restore the initial chain in preparation for loading third
1117          * party libraries (preload/needed). */
1118         head = tail = app;
1119         ldso = lib;
1120         app->next = lib;
1121         reloc_all(lib);
1122         app->next = 0;
1123
1124         /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1125
1126         /* Donate unused parts of app and library mapping to malloc */
1127         reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
1128         ehdr = (void *)lib->base;
1129         reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
1130                 ehdr->e_phentsize, ehdr->e_phnum);
1131
1132         /* Load preload/needed libraries, add their symbols to the global
1133          * namespace, and perform all remaining relocations. The main
1134          * program must be relocated LAST since it may contain copy
1135          * relocations which depend on libraries' relocations. */
1136         if (env_preload) load_preload(env_preload);
1137         load_deps(app);
1138         make_global(app);
1139
1140         reloc_all(app->next);
1141         reloc_all(app);
1142
1143         update_tls_size();
1144         if (tls_cnt) {
1145                 void *mem = mmap(0, libc.tls_size, PROT_READ|PROT_WRITE,
1146                         MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
1147                 if (mem==MAP_FAILED ||
1148                     !__install_initial_tls(__copy_tls(mem))) {
1149                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1150                                 argv[0], libc.tls_size);
1151                         _exit(127);
1152                 }
1153         }
1154
1155         if (ldso_fail) _exit(127);
1156         if (ldd_mode) _exit(0);
1157
1158         /* Switch to runtime mode: any further failures in the dynamic
1159          * linker are a reportable failure rather than a fatal startup
1160          * error. If the dynamic loader (dlopen) will not be used, free
1161          * all memory used by the dynamic linker. */
1162         runtime = 1;
1163
1164 #ifndef DYNAMIC_IS_RO
1165         for (i=0; app->dynv[i]; i+=2)
1166                 if (app->dynv[i]==DT_DEBUG)
1167                         app->dynv[i+1] = (size_t)&debug;
1168 #endif
1169         debug.ver = 1;
1170         debug.bp = _dl_debug_state;
1171         debug.head = head;
1172         debug.base = lib->base;
1173         debug.state = 0;
1174         _dl_debug_state();
1175
1176         if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
1177         __init_libc(envp, argv[0]);
1178         atexit(do_fini);
1179         errno = 0;
1180         do_init_fini(tail);
1181
1182         return (void *)aux[AT_ENTRY];
1183 }
1184
1185 void *dlopen(const char *file, int mode)
1186 {
1187         struct dso *volatile p, *orig_tail, *next;
1188         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1189         size_t i;
1190         int cs;
1191         jmp_buf jb;
1192
1193         if (!file) return head;
1194
1195         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1196         pthread_rwlock_wrlock(&lock);
1197         __inhibit_ptc();
1198
1199         p = 0;
1200         orig_tls_cnt = tls_cnt;
1201         orig_tls_offset = tls_offset;
1202         orig_tls_align = tls_align;
1203         orig_tail = tail;
1204         noload = mode & RTLD_NOLOAD;
1205
1206         rtld_fail = &jb;
1207         if (setjmp(*rtld_fail)) {
1208                 /* Clean up anything new that was (partially) loaded */
1209                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1210                         if (p->deps[i]->global < 0)
1211                                 p->deps[i]->global = 0;
1212                 for (p=orig_tail->next; p; p=next) {
1213                         next = p->next;
1214                         munmap(p->map, p->map_len);
1215                         free(p->deps);
1216                         free(p);
1217                 }
1218                 tls_cnt = orig_tls_cnt;
1219                 tls_offset = orig_tls_offset;
1220                 tls_align = orig_tls_align;
1221                 tail = orig_tail;
1222                 tail->next = 0;
1223                 p = 0;
1224                 errflag = 1;
1225                 goto end;
1226         } else p = load_library(file, head);
1227
1228         if (!p) {
1229                 snprintf(errbuf, sizeof errbuf, noload ?
1230                         "Library %s is not already loaded" :
1231                         "Error loading shared library %s: %m",
1232                         file);
1233                 errflag = 1;
1234                 goto end;
1235         }
1236
1237         /* First load handling */
1238         if (!p->deps) {
1239                 load_deps(p);
1240                 if (p->deps) for (i=0; p->deps[i]; i++)
1241                         if (!p->deps[i]->global)
1242                                 p->deps[i]->global = -1;
1243                 if (!p->global) p->global = -1;
1244                 reloc_all(p);
1245                 if (p->deps) for (i=0; p->deps[i]; i++)
1246                         if (p->deps[i]->global < 0)
1247                                 p->deps[i]->global = 0;
1248                 if (p->global < 0) p->global = 0;
1249         }
1250
1251         if (mode & RTLD_GLOBAL) {
1252                 if (p->deps) for (i=0; p->deps[i]; i++)
1253                         p->deps[i]->global = 1;
1254                 p->global = 1;
1255         }
1256
1257         update_tls_size();
1258
1259         if (ssp_used) __init_ssp(libc.auxv);
1260
1261         _dl_debug_state();
1262         orig_tail = tail;
1263 end:
1264         __release_ptc();
1265         if (p) gencnt++;
1266         pthread_rwlock_unlock(&lock);
1267         if (p) do_init_fini(orig_tail);
1268         pthread_setcancelstate(cs, 0);
1269         return p;
1270 }
1271
1272 static int invalid_dso_handle(void *h)
1273 {
1274         struct dso *p;
1275         for (p=head; p; p=p->next) if (h==p) return 0;
1276         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1277         errflag = 1;
1278         return 1;
1279 }
1280
1281 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1282 {
1283         size_t i;
1284         uint32_t h = 0, gh = 0;
1285         Sym *sym;
1286         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1287                 if (p == RTLD_DEFAULT) {
1288                         p = head;
1289                 } else if (p == RTLD_NEXT) {
1290                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1291                         if (!p) p=head;
1292                         p = p->next;
1293                 }
1294                 struct symdef def = find_sym(p, s, 0);
1295                 if (!def.sym) goto failed;
1296                 if ((def.sym->st_info&0xf) == STT_TLS)
1297                         return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1298                 return def.dso->base + def.sym->st_value;
1299         }
1300         if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1301                 return 0;
1302         if (p->ghashtab) {
1303                 gh = gnu_hash(s);
1304                 sym = gnu_lookup(s, gh, p);
1305         } else {
1306                 h = sysv_hash(s);
1307                 sym = sysv_lookup(s, h, p);
1308         }
1309         if (sym && (sym->st_info&0xf) == STT_TLS)
1310                 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1311         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1312                 return p->base + sym->st_value;
1313         if (p->deps) for (i=0; p->deps[i]; i++) {
1314                 if (p->deps[i]->ghashtab) {
1315                         if (!gh) gh = gnu_hash(s);
1316                         sym = gnu_lookup(s, gh, p->deps[i]);
1317                 } else {
1318                         if (!h) h = sysv_hash(s);
1319                         sym = sysv_lookup(s, h, p->deps[i]);
1320                 }
1321                 if (sym && (sym->st_info&0xf) == STT_TLS)
1322                         return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1323                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1324                         return p->deps[i]->base + sym->st_value;
1325         }
1326 failed:
1327         errflag = 1;
1328         snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1329         return 0;
1330 }
1331
1332 int __dladdr(void *addr, Dl_info *info)
1333 {
1334         struct dso *p;
1335         Sym *sym;
1336         uint32_t nsym;
1337         char *strings;
1338         size_t i;
1339         void *best = 0;
1340         char *bestname;
1341
1342         pthread_rwlock_rdlock(&lock);
1343         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1344         pthread_rwlock_unlock(&lock);
1345
1346         if (!p) return 0;
1347
1348         sym = p->syms;
1349         strings = p->strings;
1350         if (p->hashtab) {
1351                 nsym = p->hashtab[1];
1352         } else {
1353                 uint32_t *buckets;
1354                 uint32_t *hashval;
1355                 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1356                 sym += p->ghashtab[1];
1357                 for (i = 0; i < p->ghashtab[0]; i++) {
1358                         if (buckets[i] > nsym)
1359                                 nsym = buckets[i];
1360                 }
1361                 if (nsym) {
1362                         nsym -= p->ghashtab[1];
1363                         hashval = buckets + p->ghashtab[0] + nsym;
1364                         do nsym++;
1365                         while (!(*hashval++ & 1));
1366                 }
1367         }
1368
1369         for (; nsym; nsym--, sym++) {
1370                 if (sym->st_value
1371                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1372                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1373                         void *symaddr = p->base + sym->st_value;
1374                         if (symaddr > addr || symaddr < best)
1375                                 continue;
1376                         best = symaddr;
1377                         bestname = strings + sym->st_name;
1378                         if (addr == symaddr)
1379                                 break;
1380                 }
1381         }
1382
1383         if (!best) return 0;
1384
1385         info->dli_fname = p->name;
1386         info->dli_fbase = p->base;
1387         info->dli_sname = bestname;
1388         info->dli_saddr = best;
1389
1390         return 1;
1391 }
1392
1393 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1394 {
1395         void *res;
1396         pthread_rwlock_rdlock(&lock);
1397         res = do_dlsym(p, s, ra);
1398         pthread_rwlock_unlock(&lock);
1399         return res;
1400 }
1401
1402 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1403 {
1404         struct dso *current;
1405         struct dl_phdr_info info;
1406         int ret = 0;
1407         for(current = head; current;) {
1408                 info.dlpi_addr      = (uintptr_t)current->base;
1409                 info.dlpi_name      = current->name;
1410                 info.dlpi_phdr      = current->phdr;
1411                 info.dlpi_phnum     = current->phnum;
1412                 info.dlpi_adds      = gencnt;
1413                 info.dlpi_subs      = 0;
1414                 info.dlpi_tls_modid = current->tls_id;
1415                 info.dlpi_tls_data  = current->tls_image;
1416
1417                 ret = (callback)(&info, sizeof (info), data);
1418
1419                 if (ret != 0) break;
1420
1421                 pthread_rwlock_rdlock(&lock);
1422                 current = current->next;
1423                 pthread_rwlock_unlock(&lock);
1424         }
1425         return ret;
1426 }
1427 #else
1428 static int invalid_dso_handle(void *h)
1429 {
1430         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1431         errflag = 1;
1432         return 1;
1433 }
1434 void *dlopen(const char *file, int mode)
1435 {
1436         return 0;
1437 }
1438 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1439 {
1440         return 0;
1441 }
1442 int __dladdr (void *addr, Dl_info *info)
1443 {
1444         return 0;
1445 }
1446 #endif
1447
1448 int __dlinfo(void *dso, int req, void *res)
1449 {
1450         if (invalid_dso_handle(dso)) return -1;
1451         if (req != RTLD_DI_LINKMAP) {
1452                 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1453                 errflag = 1;
1454                 return -1;
1455         }
1456         *(struct link_map **)res = dso;
1457         return 0;
1458 }
1459
1460 char *dlerror()
1461 {
1462         if (!errflag) return 0;
1463         errflag = 0;
1464         return errbuf;
1465 }
1466
1467 int dlclose(void *p)
1468 {
1469         return invalid_dso_handle(p);
1470 }