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 int __init_tp(void *);
  94 void __init_libc(char **, char *);
  95
  96 const char *__libc_get_version(void);
  97
  98 static struct dso *head, *tail, *ldso, *fini_head;
  99 static char *env_path, *sys_path;
 100 static unsigned long long gencnt;
 101 static int ssp_used;
 102 static int runtime;
 103 static int ldd_mode;
 104 static int ldso_fail;
 105 static int noload;
 106 static jmp_buf *rtld_fail;
 107 static pthread_rwlock_t lock;
 108 static struct debug debug;
 109 static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
 110 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
 111 static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
 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_shndx != SHN_UNDEF
 258                             || sym->st_info>>4 != STB_WEAK)) {
 259                                 snprintf(errbuf, sizeof errbuf,
 260                                         "Error relocating %s: %s: symbol not found",
 261                                         dso->name, name);
 262                                 if (runtime) longjmp(*rtld_fail, 1);
 263                                 dprintf(2, "%s\n", errbuf);
 264                                 ldso_fail = 1;
 265                                 continue;
 266                         }
 267                 } else {
 268                         sym = 0;
 269                         def.sym = 0;
 270                         def.dso = 0;
 271                 }
 272                 do_single_reloc(dso, base, (void *)(base + rel[0]), type,
 273                         stride>2 ? rel[2] : 0, sym, sym?sym->st_size:0, def,
 274                         def.sym?(size_t)(def.dso->base+def.sym->st_value):0);
 275         }
 276 }
 277
 278 /* A huge hack: to make up for the wastefulness of shared libraries
 279  * needing at least a page of dirty memory even if they have no global
 280  * data, we reclaim the gaps at the beginning and end of writable maps
 281  * and "donate" them to the heap by setting up minimal malloc
 282  * structures and then freeing them. */
 283
 284 static void reclaim(unsigned char *base, size_t start, size_t end)
 285 {
 286         size_t *a, *z;
 287         start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
 288         end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
 289         if (start>end || end-start < 4*sizeof(size_t)) return;
 290         a = (size_t *)(base + start);
 291         z = (size_t *)(base + end);
 292         a[-2] = 1;
 293         a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
 294         z[1] = 1;
 295         free(a);
 296 }
 297
 298 static void reclaim_gaps(unsigned char *base, Phdr *ph, size_t phent, size_t phcnt)
 299 {
 300         for (; phcnt--; ph=(void *)((char *)ph+phent)) {
 301                 if (ph->p_type!=PT_LOAD) continue;
 302                 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
 303                 reclaim(base, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
 304                 reclaim(base, ph->p_vaddr+ph->p_memsz,
 305                         ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
 306         }
 307 }
 308
 309 static void *map_library(int fd, struct dso *dso)
 310 {
 311         Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
 312         void *allocated_buf=0;
 313         size_t phsize;
 314         size_t addr_min=SIZE_MAX, addr_max=0, map_len;
 315         size_t this_min, this_max;
 316         off_t off_start;
 317         Ehdr *eh;
 318         Phdr *ph, *ph0;
 319         unsigned prot;
 320         unsigned char *map=MAP_FAILED, *base;
 321         size_t dyn=0;
 322         size_t tls_image=0;
 323         size_t i;
 324
 325         ssize_t l = read(fd, buf, sizeof buf);
 326         eh = buf;
 327         if (l<0) return 0;
 328         if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
 329                 goto noexec;
 330         phsize = eh->e_phentsize * eh->e_phnum;
 331         if (phsize > sizeof buf - sizeof *eh) {
 332                 allocated_buf = malloc(phsize);
 333                 if (!allocated_buf) return 0;
 334                 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
 335                 if (l < 0) goto error;
 336                 if (l != phsize) goto noexec;
 337                 ph = ph0 = allocated_buf;
 338         } else if (eh->e_phoff + phsize > l) {
 339                 l = pread(fd, buf+1, phsize, eh->e_phoff);
 340                 if (l < 0) goto error;
 341                 if (l != phsize) goto noexec;
 342                 ph = ph0 = (void *)(buf + 1);
 343         } else {
 344                 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
 345         }
 346         for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 347                 if (ph->p_type == PT_DYNAMIC)
 348                         dyn = ph->p_vaddr;
 349                 if (ph->p_type == PT_TLS) {
 350                         tls_image = ph->p_vaddr;
 351                         dso->tls_align = ph->p_align;
 352                         dso->tls_len = ph->p_filesz;
 353                         dso->tls_size = ph->p_memsz;
 354                 }
 355                 if (ph->p_type != PT_LOAD) continue;
 356                 if (ph->p_vaddr < addr_min) {
 357                         addr_min = ph->p_vaddr;
 358                         off_start = ph->p_offset;
 359                         prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 360                                 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 361                                 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 362                 }
 363                 if (ph->p_vaddr+ph->p_memsz > addr_max) {
 364                         addr_max = ph->p_vaddr+ph->p_memsz;
 365                 }
 366         }
 367         if (!dyn) goto noexec;
 368         addr_max += PAGE_SIZE-1;
 369         addr_max &= -PAGE_SIZE;
 370         addr_min &= -PAGE_SIZE;
 371         off_start &= -PAGE_SIZE;
 372         map_len = addr_max - addr_min + off_start;
 373         /* The first time, we map too much, possibly even more than
 374          * the length of the file. This is okay because we will not
 375          * use the invalid part; we just need to reserve the right
 376          * amount of virtual address space to map over later. */
 377         map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
 378         if (map==MAP_FAILED) goto error;
 379         /* If the loaded file is not relocatable and the requested address is
 380          * not available, then the load operation must fail. */
 381         if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
 382                 errno = EBUSY;
 383                 goto error;
 384         }
 385         base = map - addr_min;
 386         dso->phdr = 0;
 387         dso->phnum = 0;
 388         for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
 389                 if (ph->p_type != PT_LOAD) continue;
 390                 /* Check if the programs headers are in this load segment, and
 391                  * if so, record the address for use by dl_iterate_phdr. */
 392                 if (!dso->phdr && eh->e_phoff >= ph->p_offset
 393                     && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
 394                         dso->phdr = (void *)(base + ph->p_vaddr
 395                                 + (eh->e_phoff-ph->p_offset));
 396                         dso->phnum = eh->e_phnum;
 397                 }
 398                 /* Reuse the existing mapping for the lowest-address LOAD */
 399                 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
 400                 this_min = ph->p_vaddr & -PAGE_SIZE;
 401                 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
 402                 off_start = ph->p_offset & -PAGE_SIZE;
 403                 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
 404                         ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
 405                         ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
 406                 if (mmap(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
 407                         goto error;
 408                 if (ph->p_memsz > ph->p_filesz) {
 409                         size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
 410                         size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
 411                         memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
 412                         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)
 413                                 goto error;
 414                 }
 415         }
 416         for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
 417                 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
 418                         if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC) < 0)
 419                                 goto error;
 420                         break;
 421                 }
 422         if (!runtime) reclaim_gaps(base, ph0, eh->e_phentsize, eh->e_phnum);
 423         dso->map = map;
 424         dso->map_len = map_len;
 425         dso->base = base;
 426         dso->dynv = (void *)(base+dyn);
 427         if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
 428         free(allocated_buf);
 429         return map;
 430 noexec:
 431         errno = ENOEXEC;
 432 error:
 433         if (map!=MAP_FAILED) munmap(map, map_len);
 434         free(allocated_buf);
 435         return 0;
 436 }
 437
 438 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
 439 {
 440         size_t l;
 441         int fd;
 442         for (;;) {
 443                 s += strspn(s, ":\n");
 444                 l = strcspn(s, ":\n");
 445                 if (l-1 >= INT_MAX) return -1;
 446                 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) >= buf_size)
 447                         continue;
 448                 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
 449                 s += l;
 450         }
 451 }
 452
 453 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
 454 {
 455         size_t n, l;
 456         const char *s, *t, *origin;
 457         char *d;
 458         if (p->rpath) return 0;
 459         if (!p->rpath_orig) return -1;
 460         if (!strchr(p->rpath_orig, '$')) {
 461                 p->rpath = p->rpath_orig;
 462                 return 0;
 463         }
 464         n = 0;
 465         s = p->rpath_orig;
 466         while ((t=strchr(s, '$'))) {
 467                 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
 468                         return -1;
 469                 s = t+1;
 470                 n++;
 471         }
 472         if (n > SSIZE_MAX/PATH_MAX) return -1;
 473
 474         if (p->kernel_mapped) {
 475                 /* $ORIGIN searches cannot be performed for the main program
 476                  * when it is suid/sgid/AT_SECURE. This is because the
 477                  * pathname is under the control of the caller of execve.
 478                  * For libraries, however, $ORIGIN can be processed safely
 479                  * since the library's pathname came from a trusted source
 480                  * (either system paths or a call to dlopen). */
 481                 if (libc.secure)
 482                         return -1;
 483                 l = readlink("/proc/self/exe", buf, buf_size);
 484                 if (l >= buf_size)
 485                         return -1;
 486                 buf[l] = 0;
 487                 origin = buf;
 488         } else {
 489                 origin = p->name;
 490         }
 491         t = strrchr(origin, '/');
 492         l = t ? t-origin : 0;
 493         p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
 494         if (!p->rpath) return -1;
 495
 496         d = p->rpath;
 497         s = p->rpath_orig;
 498         while ((t=strchr(s, '$'))) {
 499                 memcpy(d, s, t-s);
 500                 d += t-s;
 501                 memcpy(d, origin, l);
 502                 d += l;
 503                 /* It was determined previously that the '$' is followed
 504                  * either by "ORIGIN" or "{ORIGIN}". */
 505                 s = t + 7 + 2*(t[1]=='{');
 506         }
 507         strcpy(d, s);
 508         return 0;
 509 }
 510
 511 static void decode_dyn(struct dso *p)
 512 {
 513         size_t dyn[DYN_CNT] = {0};
 514         decode_vec(p->dynv, dyn, DYN_CNT);
 515         p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
 516         p->strings = (void *)(p->base + dyn[DT_STRTAB]);
 517         if (dyn[0]&(1<<DT_HASH))
 518                 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
 519         if (dyn[0]&(1<<DT_RPATH))
 520                 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
 521         if (search_vec(p->dynv, dyn, DT_GNU_HASH))
 522                 p->ghashtab = (void *)(p->base + *dyn);
 523         if (search_vec(p->dynv, dyn, DT_VERSYM))
 524                 p->versym = (void *)(p->base + *dyn);
 525 }
 526
 527 static struct dso *load_library(const char *name, struct dso *needed_by)
 528 {
 529         char buf[2*NAME_MAX+2];
 530         const char *pathname;
 531         unsigned char *map;
 532         struct dso *p, temp_dso = {0};
 533         int fd;
 534         struct stat st;
 535         size_t alloc_size;
 536         int n_th = 0;
 537         int is_self = 0;
 538
 539         /* Catch and block attempts to reload the implementation itself */
 540         if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
 541                 static const char *rp, reserved[] =
 542                         "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
 543                 char *z = strchr(name, '.');
 544                 if (z) {
 545                         size_t l = z-name;
 546                         for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
 547                         if (*rp) {
 548                                 if (ldd_mode) {
 549                                         /* Track which names have been resolved
 550                                          * and only report each one once. */
 551                                         static unsigned reported;
 552                                         unsigned mask = 1U<<(rp-reserved);
 553                                         if (!(reported & mask)) {
 554                                                 reported |= mask;
 555                                                 dprintf(1, "\t%s => %s (%p)\n",
 556                                                         name, ldso->name,
 557                                                         ldso->base);
 558                                         }
 559                                 }
 560                                 is_self = 1;
 561                         }
 562                 }
 563         }
 564         if (!strcmp(name, ldso->name)) is_self = 1;
 565         if (is_self) {
 566                 if (!ldso->prev) {
 567                         tail->next = ldso;
 568                         ldso->prev = tail;
 569                         tail = ldso->next ? ldso->next : ldso;
 570                 }
 571                 return ldso;
 572         }
 573         if (strchr(name, '/')) {
 574                 pathname = name;
 575                 fd = open(name, O_RDONLY|O_CLOEXEC);
 576         } else {
 577                 /* Search for the name to see if it's already loaded */
 578                 for (p=head->next; p; p=p->next) {
 579                         if (p->shortname && !strcmp(p->shortname, name)) {
 580                                 p->refcnt++;
 581                                 return p;
 582                         }
 583                 }
 584                 if (strlen(name) > NAME_MAX) return 0;
 585                 fd = -1;
 586                 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
 587                 for (p=needed_by; fd < 0 && p; p=p->needed_by)
 588                         if (!fixup_rpath(p, buf, sizeof buf))
 589                                 fd = path_open(name, p->rpath, buf, sizeof buf);
 590                 if (fd < 0) {
 591                         if (!sys_path) {
 592                                 char *prefix = 0;
 593                                 size_t prefix_len;
 594                                 if (ldso->name[0]=='/') {
 595                                         char *s, *t, *z;
 596                                         for (s=t=z=ldso->name; *s; s++)
 597                                                 if (*s=='/') z=t, t=s;
 598                                         prefix_len = z-ldso->name;
 599                                         if (prefix_len < PATH_MAX)
 600                                                 prefix = ldso->name;
 601                                 }
 602                                 if (!prefix) {
 603                                         prefix = "";
 604                                         prefix_len = 0;
 605                                 }
 606                                 char etc_ldso_path[prefix_len + 1
 607                                         + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
 608                                 snprintf(etc_ldso_path, sizeof etc_ldso_path,
 609                                         "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
 610                                         (int)prefix_len, prefix);
 611                                 FILE *f = fopen(etc_ldso_path, "rbe");
 612                                 if (f) {
 613                                         if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
 614                                                 free(sys_path);
 615                                                 sys_path = "";
 616                                         }
 617                                         fclose(f);
 618                                 } else if (errno != ENOENT) {
 619                                         sys_path = "";
 620                                 }
 621                         }
 622                         if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
 623                         fd = path_open(name, sys_path, buf, sizeof buf);
 624                 }
 625                 pathname = buf;
 626         }
 627         if (fd < 0) return 0;
 628         if (fstat(fd, &st) < 0) {
 629                 close(fd);
 630                 return 0;
 631         }
 632         for (p=head->next; p; p=p->next) {
 633                 if (p->dev == st.st_dev && p->ino == st.st_ino) {
 634                         /* If this library was previously loaded with a
 635                          * pathname but a search found the same inode,
 636                          * setup its shortname so it can be found by name. */
 637                         if (!p->shortname && pathname != name)
 638                                 p->shortname = strrchr(p->name, '/')+1;
 639                         close(fd);
 640                         p->refcnt++;
 641                         return p;
 642                 }
 643         }
 644         map = noload ? 0 : map_library(fd, &temp_dso);
 645         close(fd);
 646         if (!map) return 0;
 647
 648         /* Allocate storage for the new DSO. When there is TLS, this
 649          * storage must include a reservation for all pre-existing
 650          * threads to obtain copies of both the new TLS, and an
 651          * extended DTV capable of storing an additional slot for
 652          * the newly-loaded DSO. */
 653         alloc_size = sizeof *p + strlen(pathname) + 1;
 654         if (runtime && temp_dso.tls_image) {
 655                 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
 656                         + sizeof(void *) * (tls_cnt+3);
 657                 n_th = libc.threads_minus_1 + 1;
 658                 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
 659                 else alloc_size += n_th * per_th;
 660         }
 661         p = calloc(1, alloc_size);
 662         if (!p) {
 663                 munmap(map, temp_dso.map_len);
 664                 return 0;
 665         }
 666         memcpy(p, &temp_dso, sizeof temp_dso);
 667         decode_dyn(p);
 668         p->dev = st.st_dev;
 669         p->ino = st.st_ino;
 670         p->refcnt = 1;
 671         p->needed_by = needed_by;
 672         p->name = p->buf;
 673         strcpy(p->name, pathname);
 674         /* Add a shortname only if name arg was not an explicit pathname. */
 675         if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
 676         if (p->tls_image) {
 677                 if (runtime && !libc.has_thread_pointer) {
 678                         munmap(map, p->map_len);
 679                         free(p);
 680                         errno = ENOSYS;
 681                         return 0;
 682                 }
 683                 p->tls_id = ++tls_cnt;
 684                 tls_align = MAXP2(tls_align, p->tls_align);
 685 #ifdef TLS_ABOVE_TP
 686                 p->tls_offset = tls_offset + ( (tls_align-1) &
 687                         -(tls_offset + (uintptr_t)p->tls_image) );
 688                 tls_offset += p->tls_size;
 689 #else
 690                 tls_offset += p->tls_size + p->tls_align - 1;
 691                 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
 692                         & (p->tls_align-1);
 693                 p->tls_offset = tls_offset;
 694 #endif
 695                 p->new_dtv = (void *)(-sizeof(size_t) &
 696                         (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
 697                 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
 698         }
 699
 700         tail->next = p;
 701         p->prev = tail;
 702         tail = p;
 703
 704         if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
 705
 706         return p;
 707 }
 708
 709 static void load_deps(struct dso *p)
 710 {
 711         size_t i, ndeps=0;
 712         struct dso ***deps = &p->deps, **tmp, *dep;
 713         for (; p; p=p->next) {
 714                 for (i=0; p->dynv[i]; i+=2) {
 715                         if (p->dynv[i] != DT_NEEDED) continue;
 716                         dep = load_library(p->strings + p->dynv[i+1], p);
 717                         if (!dep) {
 718                                 snprintf(errbuf, sizeof errbuf,
 719                                         "Error loading shared library %s: %m (needed by %s)",
 720                                         p->strings + p->dynv[i+1], p->name);
 721                                 if (runtime) longjmp(*rtld_fail, 1);
 722                                 dprintf(2, "%s\n", errbuf);
 723                                 ldso_fail = 1;
 724                                 continue;
 725                         }
 726                         if (runtime) {
 727                                 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
 728                                 if (!tmp) longjmp(*rtld_fail, 1);
 729                                 tmp[ndeps++] = dep;
 730                                 tmp[ndeps] = 0;
 731                                 *deps = tmp;
 732                         }
 733                 }
 734         }
 735 }
 736
 737 static void load_preload(char *s)
 738 {
 739         int tmp;
 740         char *z;
 741         for (z=s; *z; s=z) {
 742                 for (   ; *s && isspace(*s); s++);
 743                 for (z=s; *z && !isspace(*z); z++);
 744                 tmp = *z;
 745                 *z = 0;
 746                 load_library(s, 0);
 747                 *z = tmp;
 748         }
 749 }
 750
 751 static void make_global(struct dso *p)
 752 {
 753         for (; p; p=p->next) p->global = 1;
 754 }
 755
 756 static void reloc_all(struct dso *p)
 757 {
 758         size_t dyn[DYN_CNT] = {0};
 759         for (; p; p=p->next) {
 760                 if (p->relocated) continue;
 761                 decode_vec(p->dynv, dyn, DYN_CNT);
 762 #ifdef NEED_ARCH_RELOCS
 763                 do_arch_relocs(p, head);
 764 #endif
 765                 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
 766                         2+(dyn[DT_PLTREL]==DT_RELA));
 767                 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
 768                 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
 769                 p->relocated = 1;
 770         }
 771 }
 772
 773 static size_t find_dyn(Phdr *ph, size_t cnt, size_t stride)
 774 {
 775         for (; cnt--; ph = (void *)((char *)ph + stride))
 776                 if (ph->p_type == PT_DYNAMIC)
 777                         return ph->p_vaddr;
 778         return 0;
 779 }
 780
 781 static void find_map_range(Phdr *ph, size_t cnt, size_t stride, struct dso *p)
 782 {
 783         size_t min_addr = -1, max_addr = 0;
 784         for (; cnt--; ph = (void *)((char *)ph + stride)) {
 785                 if (ph->p_type != PT_LOAD) continue;
 786                 if (ph->p_vaddr < min_addr)
 787                         min_addr = ph->p_vaddr;
 788                 if (ph->p_vaddr+ph->p_memsz > max_addr)
 789                         max_addr = ph->p_vaddr+ph->p_memsz;
 790         }
 791         min_addr &= -PAGE_SIZE;
 792         max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
 793         p->map = p->base + min_addr;
 794         p->map_len = max_addr - min_addr;
 795 }
 796
 797 static void do_fini()
 798 {
 799         struct dso *p;
 800         size_t dyn[DYN_CNT] = {0};
 801         for (p=fini_head; p; p=p->fini_next) {
 802                 if (!p->constructed) continue;
 803                 decode_vec(p->dynv, dyn, DYN_CNT);
 804                 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
 805                         size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
 806                         size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
 807                         while (n--) ((void (*)(void))*--fn)();
 808                 }
 809 #ifndef NO_LEGACY_INITFINI
 810                 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
 811                         ((void (*)(void))(p->base + dyn[DT_FINI]))();
 812 #endif
 813         }
 814 }
 815
 816 static void do_init_fini(struct dso *p)
 817 {
 818         size_t dyn[DYN_CNT] = {0};
 819         int need_locking = libc.threads_minus_1;
 820         /* Allow recursive calls that arise when a library calls
 821          * dlopen from one of its constructors, but block any
 822          * other threads until all ctors have finished. */
 823         if (need_locking) pthread_mutex_lock(&init_fini_lock);
 824         for (; p; p=p->prev) {
 825                 if (p->constructed) continue;
 826                 p->constructed = 1;
 827                 decode_vec(p->dynv, dyn, DYN_CNT);
 828                 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
 829                         p->fini_next = fini_head;
 830                         fini_head = p;
 831                 }
 832 #ifndef NO_LEGACY_INITFINI
 833                 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
 834                         ((void (*)(void))(p->base + dyn[DT_INIT]))();
 835 #endif
 836                 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
 837                         size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
 838                         size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
 839                         while (n--) ((void (*)(void))*fn++)();
 840                 }
 841                 if (!need_locking && libc.threads_minus_1) {
 842                         need_locking = 1;
 843                         pthread_mutex_lock(&init_fini_lock);
 844                 }
 845         }
 846         if (need_locking) pthread_mutex_unlock(&init_fini_lock);
 847 }
 848
 849 void _dl_debug_state(void)
 850 {
 851 }
 852
 853 void __reset_tls()
 854 {
 855         pthread_t self = __pthread_self();
 856         struct dso *p;
 857         for (p=head; p; p=p->next) {
 858                 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
 859                 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
 860                 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
 861                         p->tls_size - p->tls_len);
 862                 if (p->tls_id == (size_t)self->dtv[0]) break;
 863         }
 864 }
 865
 866 void *__copy_tls(unsigned char *mem)
 867 {
 868         pthread_t td;
 869         struct dso *p;
 870
 871         void **dtv = (void *)mem;
 872         dtv[0] = (void *)tls_cnt;
 873         if (!tls_cnt) {
 874                 td = (void *)(dtv+1);
 875                 td->dtv = dtv;
 876                 return td;
 877         }
 878
 879 #ifdef TLS_ABOVE_TP
 880         mem += sizeof(void *) * (tls_cnt+1);
 881         mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
 882         td = (pthread_t)mem;
 883         mem += sizeof(struct pthread);
 884
 885         for (p=head; p; p=p->next) {
 886                 if (!p->tls_id) continue;
 887                 dtv[p->tls_id] = mem + p->tls_offset;
 888                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 889         }
 890 #else
 891         mem += libc.tls_size - sizeof(struct pthread);
 892         mem -= (uintptr_t)mem & (tls_align-1);
 893         td = (pthread_t)mem;
 894
 895         for (p=head; p; p=p->next) {
 896                 if (!p->tls_id) continue;
 897                 dtv[p->tls_id] = mem - p->tls_offset;
 898                 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
 899         }
 900 #endif
 901         td->dtv = dtv;
 902         return td;
 903 }
 904
 905 void *__tls_get_addr(size_t *v)
 906 {
 907         pthread_t self = __pthread_self();
 908         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
 909                 return (char *)self->dtv[v[0]]+v[1];
 910
 911         /* Block signals to make accessing new TLS async-signal-safe */
 912         sigset_t set;
 913         pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
 914         if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
 915                 pthread_sigmask(SIG_SETMASK, &set, 0);
 916                 return (char *)self->dtv[v[0]]+v[1];
 917         }
 918
 919         /* This is safe without any locks held because, if the caller
 920          * is able to request the Nth entry of the DTV, the DSO list
 921          * must be valid at least that far out and it was synchronized
 922          * at program startup or by an already-completed call to dlopen. */
 923         struct dso *p;
 924         for (p=head; p->tls_id != v[0]; p=p->next);
 925
 926         /* Get new DTV space from new DSO if needed */
 927         if (v[0] > (size_t)self->dtv[0]) {
 928                 void **newdtv = p->new_dtv +
 929                         (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
 930                 memcpy(newdtv, self->dtv,
 931                         ((size_t)self->dtv[0]+1) * sizeof(void *));
 932                 newdtv[0] = (void *)v[0];
 933                 self->dtv = newdtv;
 934         }
 935
 936         /* Get new TLS memory from new DSO */
 937         unsigned char *mem = p->new_tls +
 938                 (p->tls_size + p->tls_align) * a_fetch_add(&p->new_tls_idx,1);
 939         mem += ((uintptr_t)p->tls_image - (uintptr_t)mem) & (p->tls_align-1);
 940         self->dtv[v[0]] = mem;
 941         memcpy(mem, p->tls_image, p->tls_len);
 942         pthread_sigmask(SIG_SETMASK, &set, 0);
 943         return mem + v[1];
 944 }
 945
 946 static void update_tls_size()
 947 {
 948         libc.tls_size = ALIGN(
 949                 (1+tls_cnt) * sizeof(void *) +
 950                 tls_offset +
 951                 sizeof(struct pthread) +
 952                 tls_align * 2,
 953         tls_align);
 954 }
 955
 956 void *__dynlink(int argc, char **argv)
 957 {
 958         size_t aux[AUX_CNT] = {0};
 959         size_t i;
 960         Phdr *phdr;
 961         Ehdr *ehdr;
 962         static struct dso builtin_dsos[3];
 963         struct dso *const app = builtin_dsos+0;
 964         struct dso *const lib = builtin_dsos+1;
 965         struct dso *const vdso = builtin_dsos+2;
 966         char *env_preload=0;
 967         size_t vdso_base;
 968         size_t *auxv;
 969         char **envp = argv+argc+1;
 970         void *initial_tls;
 971
 972         /* Find aux vector just past environ[] */
 973         for (i=argc+1; argv[i]; i++)
 974                 if (!memcmp(argv[i], "LD_LIBRARY_PATH=", 16))
 975                         env_path = argv[i]+16;
 976                 else if (!memcmp(argv[i], "LD_PRELOAD=", 11))
 977                         env_preload = argv[i]+11;
 978         auxv = (void *)(argv+i+1);
 979
 980         decode_vec(auxv, aux, AUX_CNT);
 981
 982         /* Only trust user/env if kernel says we're not suid/sgid */
 983         if ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
 984           || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]) {
 985                 env_path = 0;
 986                 env_preload = 0;
 987                 libc.secure = 1;
 988         }
 989         libc.page_size = aux[AT_PAGESZ];
 990
 991         /* If the dynamic linker was invoked as a program itself, AT_BASE
 992          * will not be set. In that case, we assume the base address is
 993          * the start of the page containing the PHDRs; I don't know any
 994          * better approach... */
 995         if (!aux[AT_BASE]) {
 996                 aux[AT_BASE] = aux[AT_PHDR] & -PAGE_SIZE;
 997                 aux[AT_PHDR] = aux[AT_PHENT] = aux[AT_PHNUM] = 0;
 998         }
 999
1000         /* The dynamic linker load address is passed by the kernel
1001          * in the AUX vector, so this is easy. */
1002         lib->base = (void *)aux[AT_BASE];
1003         lib->name = lib->shortname = "libc.so";
1004         lib->global = 1;
1005         lib->kernel_mapped = 1;
1006         ehdr = (void *)lib->base;
1007         lib->phnum = ehdr->e_phnum;
1008         lib->phdr = (void *)(aux[AT_BASE]+ehdr->e_phoff);
1009         find_map_range(lib->phdr, ehdr->e_phnum, ehdr->e_phentsize, lib);
1010         lib->dynv = (void *)(lib->base + find_dyn(lib->phdr,
1011                 ehdr->e_phnum, ehdr->e_phentsize));
1012         decode_dyn(lib);
1013
1014         if (aux[AT_PHDR]) {
1015                 size_t interp_off = 0;
1016                 size_t tls_image = 0;
1017                 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1018                 app->phdr = phdr = (void *)aux[AT_PHDR];
1019                 app->phnum = aux[AT_PHNUM];
1020                 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1021                         if (phdr->p_type == PT_PHDR)
1022                                 app->base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1023                         else if (phdr->p_type == PT_INTERP)
1024                                 interp_off = (size_t)phdr->p_vaddr;
1025                         else if (phdr->p_type == PT_TLS) {
1026                                 tls_image = phdr->p_vaddr;
1027                                 app->tls_len = phdr->p_filesz;
1028                                 app->tls_size = phdr->p_memsz;
1029                                 app->tls_align = phdr->p_align;
1030                         }
1031                 }
1032                 if (app->tls_size) app->tls_image = (char *)app->base + tls_image;
1033                 if (interp_off) lib->name = (char *)app->base + interp_off;
1034                 if ((aux[0] & (1UL<<AT_EXECFN))
1035                     && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1036                         app->name = (char *)aux[AT_EXECFN];
1037                 else
1038                         app->name = argv[0];
1039                 app->kernel_mapped = 1;
1040                 app->dynv = (void *)(app->base + find_dyn(
1041                         (void *)aux[AT_PHDR], aux[AT_PHNUM], aux[AT_PHENT]));
1042                 find_map_range((void *)aux[AT_PHDR],
1043                         aux[AT_PHNUM], aux[AT_PHENT], app);
1044         } else {
1045                 int fd;
1046                 char *ldname = argv[0];
1047                 size_t l = strlen(ldname);
1048                 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1049                 *argv++ = (void *)-1;
1050                 if (argv[0] && !strcmp(argv[0], "--")) *argv++ = (void *)-1;
1051                 if (!argv[0]) {
1052                         dprintf(2, "musl libc\n"
1053                                 "Version %s\n"
1054                                 "Dynamic Program Loader\n"
1055                                 "Usage: %s [--] pathname%s\n",
1056                                 __libc_get_version(), ldname,
1057                                 ldd_mode ? "" : " [args]");
1058                         _exit(1);
1059                 }
1060                 fd = open(argv[0], O_RDONLY);
1061                 if (fd < 0) {
1062                         dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1063                         _exit(1);
1064                 }
1065                 runtime = 1;
1066                 ehdr = (void *)map_library(fd, app);
1067                 if (!ehdr) {
1068                         dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1069                         _exit(1);
1070                 }
1071                 runtime = 0;
1072                 close(fd);
1073                 lib->name = ldname;
1074                 app->name = argv[0];
1075                 aux[AT_ENTRY] = (size_t)app->base + ehdr->e_entry;
1076                 /* Find the name that would have been used for the dynamic
1077                  * linker had ldd not taken its place. */
1078                 if (ldd_mode) {
1079                         for (i=0; i<app->phnum; i++) {
1080                                 if (app->phdr[i].p_type == PT_INTERP)
1081                                         lib->name = (void *)(app->base
1082                                                 + app->phdr[i].p_vaddr);
1083                         }
1084                         dprintf(1, "\t%s (%p)\n", lib->name, lib->base);
1085                 }
1086         }
1087         if (app->tls_size) {
1088                 app->tls_id = tls_cnt = 1;
1089 #ifdef TLS_ABOVE_TP
1090                 app->tls_offset = 0;
1091                 tls_offset = app->tls_size
1092                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1093                         & (app->tls_align-1) );
1094 #else
1095                 tls_offset = app->tls_offset = app->tls_size
1096                         + ( -((uintptr_t)app->tls_image + app->tls_size)
1097                         & (app->tls_align-1) );
1098 #endif
1099                 tls_align = MAXP2(tls_align, app->tls_align);
1100         }
1101         app->global = 1;
1102         decode_dyn(app);
1103
1104         /* Attach to vdso, if provided by the kernel */
1105         if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1106                 ehdr = (void *)vdso_base;
1107                 vdso->phdr = phdr = (void *)(vdso_base + ehdr->e_phoff);
1108                 vdso->phnum = ehdr->e_phnum;
1109                 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1110                         if (phdr->p_type == PT_DYNAMIC)
1111                                 vdso->dynv = (void *)(vdso_base + phdr->p_offset);
1112                         if (phdr->p_type == PT_LOAD)
1113                                 vdso->base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1114                 }
1115                 vdso->name = "";
1116                 vdso->shortname = "linux-gate.so.1";
1117                 vdso->global = 1;
1118                 decode_dyn(vdso);
1119                 vdso->prev = lib;
1120                 lib->next = vdso;
1121         }
1122
1123         /* Initial dso chain consists only of the app. We temporarily
1124          * append the dynamic linker/libc so we can relocate it, then
1125          * restore the initial chain in preparation for loading third
1126          * party libraries (preload/needed). */
1127         head = tail = app;
1128         ldso = lib;
1129         app->next = lib;
1130         reloc_all(lib);
1131         app->next = 0;
1132
1133         /* PAST THIS POINT, ALL LIBC INTERFACES ARE FULLY USABLE. */
1134
1135         /* Donate unused parts of app and library mapping to malloc */
1136         reclaim_gaps(app->base, (void *)aux[AT_PHDR], aux[AT_PHENT], aux[AT_PHNUM]);
1137         ehdr = (void *)lib->base;
1138         reclaim_gaps(lib->base, (void *)(lib->base+ehdr->e_phoff),
1139                 ehdr->e_phentsize, ehdr->e_phnum);
1140
1141         /* Load preload/needed libraries, add their symbols to the global
1142          * namespace, and perform all remaining relocations. The main
1143          * program must be relocated LAST since it may contain copy
1144          * relocations which depend on libraries' relocations. */
1145         if (env_preload) load_preload(env_preload);
1146         load_deps(app);
1147         make_global(app);
1148
1149         reloc_all(app->next);
1150         reloc_all(app);
1151
1152         update_tls_size();
1153         if (libc.tls_size > sizeof builtin_tls) {
1154                 initial_tls = calloc(libc.tls_size, 1);
1155                 if (!initial_tls) {
1156                         dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1157                                 argv[0], libc.tls_size);
1158                         _exit(127);
1159                 }
1160         } else {
1161                 initial_tls = builtin_tls;
1162         }
1163         if (__init_tp(__copy_tls(initial_tls)) < 0 && tls_cnt) {
1164                 dprintf(2, "%s: Thread-local storage not supported by kernel.\n", argv[0]);
1165                 _exit(127);
1166         }
1167
1168         if (ldso_fail) _exit(127);
1169         if (ldd_mode) _exit(0);
1170
1171         /* Switch to runtime mode: any further failures in the dynamic
1172          * linker are a reportable failure rather than a fatal startup
1173          * error. If the dynamic loader (dlopen) will not be used, free
1174          * all memory used by the dynamic linker. */
1175         runtime = 1;
1176
1177 #ifndef DYNAMIC_IS_RO
1178         for (i=0; app->dynv[i]; i+=2)
1179                 if (app->dynv[i]==DT_DEBUG)
1180                         app->dynv[i+1] = (size_t)&debug;
1181 #endif
1182         debug.ver = 1;
1183         debug.bp = _dl_debug_state;
1184         debug.head = head;
1185         debug.base = lib->base;
1186         debug.state = 0;
1187         _dl_debug_state();
1188
1189         if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
1190         __init_libc(envp, argv[0]);
1191         atexit(do_fini);
1192         errno = 0;
1193         do_init_fini(tail);
1194
1195         return (void *)aux[AT_ENTRY];
1196 }
1197
1198 void *dlopen(const char *file, int mode)
1199 {
1200         struct dso *volatile p, *orig_tail, *next;
1201         size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1202         size_t i;
1203         int cs;
1204         jmp_buf jb;
1205
1206         if (!file) return head;
1207
1208         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1209         pthread_rwlock_wrlock(&lock);
1210         __inhibit_ptc();
1211
1212         p = 0;
1213         orig_tls_cnt = tls_cnt;
1214         orig_tls_offset = tls_offset;
1215         orig_tls_align = tls_align;
1216         orig_tail = tail;
1217         noload = mode & RTLD_NOLOAD;
1218
1219         rtld_fail = &jb;
1220         if (setjmp(*rtld_fail)) {
1221                 /* Clean up anything new that was (partially) loaded */
1222                 if (p && p->deps) for (i=0; p->deps[i]; i++)
1223                         if (p->deps[i]->global < 0)
1224                                 p->deps[i]->global = 0;
1225                 for (p=orig_tail->next; p; p=next) {
1226                         next = p->next;
1227                         munmap(p->map, p->map_len);
1228                         free(p->deps);
1229                         free(p);
1230                 }
1231                 tls_cnt = orig_tls_cnt;
1232                 tls_offset = orig_tls_offset;
1233                 tls_align = orig_tls_align;
1234                 tail = orig_tail;
1235                 tail->next = 0;
1236                 p = 0;
1237                 errflag = 1;
1238                 goto end;
1239         } else p = load_library(file, head);
1240
1241         if (!p) {
1242                 snprintf(errbuf, sizeof errbuf, noload ?
1243                         "Library %s is not already loaded" :
1244                         "Error loading shared library %s: %m",
1245                         file);
1246                 errflag = 1;
1247                 goto end;
1248         }
1249
1250         /* First load handling */
1251         if (!p->deps) {
1252                 load_deps(p);
1253                 if (p->deps) for (i=0; p->deps[i]; i++)
1254                         if (!p->deps[i]->global)
1255                                 p->deps[i]->global = -1;
1256                 if (!p->global) p->global = -1;
1257                 reloc_all(p);
1258                 if (p->deps) for (i=0; p->deps[i]; i++)
1259                         if (p->deps[i]->global < 0)
1260                                 p->deps[i]->global = 0;
1261                 if (p->global < 0) p->global = 0;
1262         }
1263
1264         if (mode & RTLD_GLOBAL) {
1265                 if (p->deps) for (i=0; p->deps[i]; i++)
1266                         p->deps[i]->global = 1;
1267                 p->global = 1;
1268         }
1269
1270         update_tls_size();
1271
1272         if (ssp_used) __init_ssp(libc.auxv);
1273
1274         _dl_debug_state();
1275         orig_tail = tail;
1276 end:
1277         __release_ptc();
1278         if (p) gencnt++;
1279         pthread_rwlock_unlock(&lock);
1280         if (p) do_init_fini(orig_tail);
1281         pthread_setcancelstate(cs, 0);
1282         return p;
1283 }
1284
1285 static int invalid_dso_handle(void *h)
1286 {
1287         struct dso *p;
1288         for (p=head; p; p=p->next) if (h==p) return 0;
1289         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1290         errflag = 1;
1291         return 1;
1292 }
1293
1294 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1295 {
1296         size_t i;
1297         uint32_t h = 0, gh = 0;
1298         Sym *sym;
1299         if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1300                 if (p == RTLD_DEFAULT) {
1301                         p = head;
1302                 } else if (p == RTLD_NEXT) {
1303                         for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1304                         if (!p) p=head;
1305                         p = p->next;
1306                 }
1307                 struct symdef def = find_sym(p, s, 0);
1308                 if (!def.sym) goto failed;
1309                 if ((def.sym->st_info&0xf) == STT_TLS)
1310                         return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1311                 return def.dso->base + def.sym->st_value;
1312         }
1313         if (p != RTLD_DEFAULT && p != RTLD_NEXT && invalid_dso_handle(p))
1314                 return 0;
1315         if (p->ghashtab) {
1316                 gh = gnu_hash(s);
1317                 sym = gnu_lookup(s, gh, p);
1318         } else {
1319                 h = sysv_hash(s);
1320                 sym = sysv_lookup(s, h, p);
1321         }
1322         if (sym && (sym->st_info&0xf) == STT_TLS)
1323                 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1324         if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1325                 return p->base + sym->st_value;
1326         if (p->deps) for (i=0; p->deps[i]; i++) {
1327                 if (p->deps[i]->ghashtab) {
1328                         if (!gh) gh = gnu_hash(s);
1329                         sym = gnu_lookup(s, gh, p->deps[i]);
1330                 } else {
1331                         if (!h) h = sysv_hash(s);
1332                         sym = sysv_lookup(s, h, p->deps[i]);
1333                 }
1334                 if (sym && (sym->st_info&0xf) == STT_TLS)
1335                         return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1336                 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1337                         return p->deps[i]->base + sym->st_value;
1338         }
1339 failed:
1340         errflag = 1;
1341         snprintf(errbuf, sizeof errbuf, "Symbol not found: %s", s);
1342         return 0;
1343 }
1344
1345 int __dladdr(const void *addr, Dl_info *info)
1346 {
1347         struct dso *p;
1348         Sym *sym;
1349         uint32_t nsym;
1350         char *strings;
1351         size_t i;
1352         void *best = 0;
1353         char *bestname;
1354
1355         pthread_rwlock_rdlock(&lock);
1356         for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1357         pthread_rwlock_unlock(&lock);
1358
1359         if (!p) return 0;
1360
1361         sym = p->syms;
1362         strings = p->strings;
1363         if (p->hashtab) {
1364                 nsym = p->hashtab[1];
1365         } else {
1366                 uint32_t *buckets;
1367                 uint32_t *hashval;
1368                 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1369                 sym += p->ghashtab[1];
1370                 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1371                         if (buckets[i] > nsym)
1372                                 nsym = buckets[i];
1373                 }
1374                 if (nsym) {
1375                         nsym -= p->ghashtab[1];
1376                         hashval = buckets + p->ghashtab[0] + nsym;
1377                         do nsym++;
1378                         while (!(*hashval++ & 1));
1379                 }
1380         }
1381
1382         for (; nsym; nsym--, sym++) {
1383                 if (sym->st_value
1384                  && (1<<(sym->st_info&0xf) & OK_TYPES)
1385                  && (1<<(sym->st_info>>4) & OK_BINDS)) {
1386                         void *symaddr = p->base + sym->st_value;
1387                         if (symaddr > addr || symaddr < best)
1388                                 continue;
1389                         best = symaddr;
1390                         bestname = strings + sym->st_name;
1391                         if (addr == symaddr)
1392                                 break;
1393                 }
1394         }
1395
1396         if (!best) return 0;
1397
1398         info->dli_fname = p->name;
1399         info->dli_fbase = p->base;
1400         info->dli_sname = bestname;
1401         info->dli_saddr = best;
1402
1403         return 1;
1404 }
1405
1406 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1407 {
1408         void *res;
1409         pthread_rwlock_rdlock(&lock);
1410         res = do_dlsym(p, s, ra);
1411         pthread_rwlock_unlock(&lock);
1412         return res;
1413 }
1414
1415 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1416 {
1417         struct dso *current;
1418         struct dl_phdr_info info;
1419         int ret = 0;
1420         for(current = head; current;) {
1421                 info.dlpi_addr      = (uintptr_t)current->base;
1422                 info.dlpi_name      = current->name;
1423                 info.dlpi_phdr      = current->phdr;
1424                 info.dlpi_phnum     = current->phnum;
1425                 info.dlpi_adds      = gencnt;
1426                 info.dlpi_subs      = 0;
1427                 info.dlpi_tls_modid = current->tls_id;
1428                 info.dlpi_tls_data  = current->tls_image;
1429
1430                 ret = (callback)(&info, sizeof (info), data);
1431
1432                 if (ret != 0) break;
1433
1434                 pthread_rwlock_rdlock(&lock);
1435                 current = current->next;
1436                 pthread_rwlock_unlock(&lock);
1437         }
1438         return ret;
1439 }
1440 #else
1441 static int invalid_dso_handle(void *h)
1442 {
1443         snprintf(errbuf, sizeof errbuf, "Invalid library handle %p", (void *)h);
1444         errflag = 1;
1445         return 1;
1446 }
1447 void *dlopen(const char *file, int mode)
1448 {
1449         return 0;
1450 }
1451 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1452 {
1453         return 0;
1454 }
1455 int __dladdr (const void *addr, Dl_info *info)
1456 {
1457         return 0;
1458 }
1459 #endif
1460
1461 int __dlinfo(void *dso, int req, void *res)
1462 {
1463         if (invalid_dso_handle(dso)) return -1;
1464         if (req != RTLD_DI_LINKMAP) {
1465                 snprintf(errbuf, sizeof errbuf, "Unsupported request %d", req);
1466                 errflag = 1;
1467                 return -1;
1468         }
1469         *(struct link_map **)res = dso;
1470         return 0;
1471 }
1472
1473 char *dlerror()
1474 {
1475         if (!errflag) return 0;
1476         errflag = 0;
1477         return errbuf;
1478 }
1479
1480 int dlclose(void *p)
1481 {
1482         return invalid_dso_handle(p);
1483 }