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overhaul shared library ctor execution for dependency order, concurrency
[musl.git] / ldso / dynlink.c
blob777be4895a07a654ecb50576bbf9c0619f227371
1 #define _GNU_SOURCE
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <stdarg.h>
5 #include <stddef.h>
6 #include <string.h>
7 #include <unistd.h>
8 #include <stdint.h>
9 #include <elf.h>
10 #include <sys/mman.h>
11 #include <limits.h>
12 #include <fcntl.h>
13 #include <sys/stat.h>
14 #include <errno.h>
15 #include <link.h>
16 #include <setjmp.h>
17 #include <pthread.h>
18 #include <ctype.h>
19 #include <dlfcn.h>
20 #include <semaphore.h>
21 #include <sys/membarrier.h>
22 #include "pthread_impl.h"
23 #include "libc.h"
24 #include "dynlink.h"
25 #include "malloc_impl.h"
26
27 static void error(const char *, ...);
28
29 #define MAXP2(a,b) (-(-(a)&-(b)))
30 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
31
32 #define container_of(p,t,m) ((t*)((char *)(p)-offsetof(t,m)))
33
34 struct debug {
35 int ver;
36 void *head;
37 void (*bp)(void);
38 int state;
39 void *base;
40 };
41
42 struct td_index {
43 size_t args[2];
44 struct td_index *next;
45 };
46
47 struct dso {
48 #if DL_FDPIC
49 struct fdpic_loadmap *loadmap;
50 #else
51 unsigned char *base;
52 #endif
53 char *name;
54 size_t *dynv;
55 struct dso *next, *prev;
56
57 Phdr *phdr;
58 int phnum;
59 size_t phentsize;
60 Sym *syms;
61 Elf_Symndx *hashtab;
62 uint32_t *ghashtab;
63 int16_t *versym;
64 char *strings;
65 struct dso *syms_next, *lazy_next;
66 size_t *lazy, lazy_cnt;
67 unsigned char *map;
68 size_t map_len;
69 dev_t dev;
70 ino_t ino;
71 char relocated;
72 char constructed;
73 char kernel_mapped;
74 char mark;
75 char bfs_built;
76 char runtime_loaded;
77 struct dso **deps, *needed_by;
78 size_t ndeps_direct;
79 size_t next_dep;
80 int ctor_visitor;
81 char *rpath_orig, *rpath;
82 struct tls_module tls;
83 size_t tls_id;
84 size_t relro_start, relro_end;
85 uintptr_t *new_dtv;
86 unsigned char *new_tls;
87 volatile int new_dtv_idx, new_tls_idx;
88 struct td_index *td_index;
89 struct dso *fini_next;
90 char *shortname;
91 #if DL_FDPIC
92 unsigned char *base;
93 #else
94 struct fdpic_loadmap *loadmap;
95 #endif
96 struct funcdesc {
97 void *addr;
98 size_t *got;
99 } *funcdescs;
100 size_t *got;
101 char buf[];
102 };
103
104 struct symdef {
105 Sym *sym;
106 struct dso *dso;
107 };
108
109 static struct builtin_tls {
110 char c;
111 struct pthread pt;
112 void *space[16];
113 } builtin_tls[1];
114 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
115
116 #define ADDEND_LIMIT 4096
117 static size_t *saved_addends, *apply_addends_to;
118
119 static struct dso ldso;
120 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
121 static char *env_path, *sys_path;
122 static unsigned long long gencnt;
123 static int runtime;
124 static int ldd_mode;
125 static int ldso_fail;
126 static int noload;
127 static jmp_buf *rtld_fail;
128 static pthread_rwlock_t lock;
129 static struct debug debug;
130 static struct tls_module *tls_tail;
131 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
132 static size_t static_tls_cnt;
133 static pthread_mutex_t init_fini_lock;
134 static pthread_cond_t ctor_cond;
135 static struct dso **main_ctor_queue;
136 static struct fdpic_loadmap *app_loadmap;
137 static struct fdpic_dummy_loadmap app_dummy_loadmap;
138
139 struct debug *_dl_debug_addr = &debug;
140
141 extern hidden int __malloc_replaced;
142
143 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
144
145 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
146
147 weak_alias(__init_array_start, __init_array_end);
148 weak_alias(__fini_array_start, __fini_array_end);
149
150 static int dl_strcmp(const char *l, const char *r)
151 {
152 for (; *l==*r && *l; l++, r++);
153 return *(unsigned char *)l - *(unsigned char *)r;
154 }
155 #define strcmp(l,r) dl_strcmp(l,r)
156
157 /* Compute load address for a virtual address in a given dso. */
158 #if DL_FDPIC
159 static void *laddr(const struct dso *p, size_t v)
160 {
161 size_t j=0;
162 if (!p->loadmap) return p->base + v;
163 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
164 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
165 }
166 static void *laddr_pg(const struct dso *p, size_t v)
167 {
168 size_t j=0;
169 size_t pgsz = PAGE_SIZE;
170 if (!p->loadmap) return p->base + v;
171 for (j=0; ; j++) {
172 size_t a = p->loadmap->segs[j].p_vaddr;
173 size_t b = a + p->loadmap->segs[j].p_memsz;
174 a &= -pgsz;
175 b += pgsz-1;
176 b &= -pgsz;
177 if (v-a<b-a) break;
178 }
179 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
180 }
181 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
182 laddr(p, v), (p)->got })
183 #else
184 #define laddr(p, v) (void *)((p)->base + (v))
185 #define laddr_pg(p, v) laddr(p, v)
186 #define fpaddr(p, v) ((void (*)())laddr(p, v))
187 #endif
188
189 static void decode_vec(size_t *v, size_t *a, size_t cnt)
190 {
191 size_t i;
192 for (i=0; i<cnt; i++) a[i] = 0;
193 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
194 a[0] |= 1UL<<v[0];
195 a[v[0]] = v[1];
196 }
197 }
198
199 static int search_vec(size_t *v, size_t *r, size_t key)
200 {
201 for (; v[0]!=key; v+=2)
202 if (!v[0]) return 0;
203 *r = v[1];
204 return 1;
205 }
206
207 static uint32_t sysv_hash(const char *s0)
208 {
209 const unsigned char *s = (void *)s0;
210 uint_fast32_t h = 0;
211 while (*s) {
212 h = 16*h + *s++;
213 h ^= h>>24 & 0xf0;
214 }
215 return h & 0xfffffff;
216 }
217
218 static uint32_t gnu_hash(const char *s0)
219 {
220 const unsigned char *s = (void *)s0;
221 uint_fast32_t h = 5381;
222 for (; *s; s++)
223 h += h*32 + *s;
224 return h;
225 }
226
227 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
228 {
229 size_t i;
230 Sym *syms = dso->syms;
231 Elf_Symndx *hashtab = dso->hashtab;
232 char *strings = dso->strings;
233 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
234 if ((!dso->versym || dso->versym[i] >= 0)
235 && (!strcmp(s, strings+syms[i].st_name)))
236 return syms+i;
237 }
238 return 0;
239 }
240
241 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
242 {
243 uint32_t nbuckets = hashtab[0];
244 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
245 uint32_t i = buckets[h1 % nbuckets];
246
247 if (!i) return 0;
248
249 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
250
251 for (h1 |= 1; ; i++) {
252 uint32_t h2 = *hashval++;
253 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
254 && !strcmp(s, dso->strings + dso->syms[i].st_name))
255 return dso->syms+i;
256 if (h2 & 1) break;
257 }
258
259 return 0;
260 }
261
262 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
263 {
264 const size_t *bloomwords = (const void *)(hashtab+4);
265 size_t f = bloomwords[fofs & (hashtab[2]-1)];
266 if (!(f & fmask)) return 0;
267
268 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
269 if (!(f & 1)) return 0;
270
271 return gnu_lookup(h1, hashtab, dso, s);
272 }
273
274 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
275 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
276
277 #ifndef ARCH_SYM_REJECT_UND
278 #define ARCH_SYM_REJECT_UND(s) 0
279 #endif
280
281 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
282 {
283 uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
284 size_t ghm = 1ul << gh % (8*sizeof(size_t));
285 struct symdef def = {0};
286 for (; dso; dso=dso->syms_next) {
287 Sym *sym;
288 if ((ght = dso->ghashtab)) {
289 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
290 } else {
291 if (!h) h = sysv_hash(s);
292 sym = sysv_lookup(s, h, dso);
293 }
294 if (!sym) continue;
295 if (!sym->st_shndx)
296 if (need_def || (sym->st_info&0xf) == STT_TLS
297 || ARCH_SYM_REJECT_UND(sym))
298 continue;
299 if (!sym->st_value)
300 if ((sym->st_info&0xf) != STT_TLS)
301 continue;
302 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
303 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
304 def.sym = sym;
305 def.dso = dso;
306 break;
307 }
308 return def;
309 }
310
311 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
312 {
313 unsigned char *base = dso->base;
314 Sym *syms = dso->syms;
315 char *strings = dso->strings;
316 Sym *sym;
317 const char *name;
318 void *ctx;
319 int type;
320 int sym_index;
321 struct symdef def;
322 size_t *reloc_addr;
323 size_t sym_val;
324 size_t tls_val;
325 size_t addend;
326 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
327
328 if (dso == &ldso) {
329 /* Only ldso's REL table needs addend saving/reuse. */
330 if (rel == apply_addends_to)
331 reuse_addends = 1;
332 skip_relative = 1;
333 }
334
335 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
336 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
337 type = R_TYPE(rel[1]);
338 if (type == REL_NONE) continue;
339 reloc_addr = laddr(dso, rel[0]);
340
341 if (stride > 2) {
342 addend = rel[2];
343 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
344 addend = 0;
345 } else if (reuse_addends) {
346 /* Save original addend in stage 2 where the dso
347 * chain consists of just ldso; otherwise read back
348 * saved addend since the inline one was clobbered. */
349 if (head==&ldso)
350 saved_addends[save_slot] = *reloc_addr;
351 addend = saved_addends[save_slot++];
352 } else {
353 addend = *reloc_addr;
354 }
355
356 sym_index = R_SYM(rel[1]);
357 if (sym_index) {
358 sym = syms + sym_index;
359 name = strings + sym->st_name;
360 ctx = type==REL_COPY ? head->syms_next : head;
361 def = (sym->st_info&0xf) == STT_SECTION
362 ? (struct symdef){ .dso = dso, .sym = sym }
363 : find_sym(ctx, name, type==REL_PLT);
364 if (!def.sym && (sym->st_shndx != SHN_UNDEF
365 || sym->st_info>>4 != STB_WEAK)) {
366 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
367 dso->lazy[3*dso->lazy_cnt+0] = rel[0];
368 dso->lazy[3*dso->lazy_cnt+1] = rel[1];
369 dso->lazy[3*dso->lazy_cnt+2] = addend;
370 dso->lazy_cnt++;
371 continue;
372 }
373 error("Error relocating %s: %s: symbol not found",
374 dso->name, name);
375 if (runtime) longjmp(*rtld_fail, 1);
376 continue;
377 }
378 } else {
379 sym = 0;
380 def.sym = 0;
381 def.dso = dso;
382 }
383
384 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
385 tls_val = def.sym ? def.sym->st_value : 0;
386
387 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
388 && runtime && def.dso->tls_id > static_tls_cnt) {
389 error("Error relocating %s: %s: initial-exec TLS "
390 "resolves to dynamic definition in %s",
391 dso->name, name, def.dso->name);
392 longjmp(*rtld_fail, 1);
393 }
394
395 switch(type) {
396 case REL_NONE:
397 break;
398 case REL_OFFSET:
399 addend -= (size_t)reloc_addr;
400 case REL_SYMBOLIC:
401 case REL_GOT:
402 case REL_PLT:
403 *reloc_addr = sym_val + addend;
404 break;
405 case REL_RELATIVE:
406 *reloc_addr = (size_t)base + addend;
407 break;
408 case REL_SYM_OR_REL:
409 if (sym) *reloc_addr = sym_val + addend;
410 else *reloc_addr = (size_t)base + addend;
411 break;
412 case REL_COPY:
413 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
414 break;
415 case REL_OFFSET32:
416 *(uint32_t *)reloc_addr = sym_val + addend
417 - (size_t)reloc_addr;
418 break;
419 case REL_FUNCDESC:
420 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
421 + (def.sym - def.dso->syms)) : 0;
422 break;
423 case REL_FUNCDESC_VAL:
424 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
425 else *reloc_addr = sym_val;
426 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
427 break;
428 case REL_DTPMOD:
429 *reloc_addr = def.dso->tls_id;
430 break;
431 case REL_DTPOFF:
432 *reloc_addr = tls_val + addend - DTP_OFFSET;
433 break;
434 #ifdef TLS_ABOVE_TP
435 case REL_TPOFF:
436 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
437 break;
438 #else
439 case REL_TPOFF:
440 *reloc_addr = tls_val - def.dso->tls.offset + addend;
441 break;
442 case REL_TPOFF_NEG:
443 *reloc_addr = def.dso->tls.offset - tls_val + addend;
444 break;
445 #endif
446 case REL_TLSDESC:
447 if (stride<3) addend = reloc_addr[1];
448 if (runtime && def.dso->tls_id > static_tls_cnt) {
449 struct td_index *new = malloc(sizeof *new);
450 if (!new) {
451 error(
452 "Error relocating %s: cannot allocate TLSDESC for %s",
453 dso->name, sym ? name : "(local)" );
454 longjmp(*rtld_fail, 1);
455 }
456 new->next = dso->td_index;
457 dso->td_index = new;
458 new->args[0] = def.dso->tls_id;
459 new->args[1] = tls_val + addend - DTP_OFFSET;
460 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
461 reloc_addr[1] = (size_t)new;
462 } else {
463 reloc_addr[0] = (size_t)__tlsdesc_static;
464 #ifdef TLS_ABOVE_TP
465 reloc_addr[1] = tls_val + def.dso->tls.offset
466 + TPOFF_K + addend;
467 #else
468 reloc_addr[1] = tls_val - def.dso->tls.offset
469 + addend;
470 #endif
471 }
472 #ifdef TLSDESC_BACKWARDS
473 /* Some archs (32-bit ARM at least) invert the order of
474 * the descriptor members. Fix them up here. */
475 size_t tmp = reloc_addr[0];
476 reloc_addr[0] = reloc_addr[1];
477 reloc_addr[1] = tmp;
478 #endif
479 break;
480 default:
481 error("Error relocating %s: unsupported relocation type %d",
482 dso->name, type);
483 if (runtime) longjmp(*rtld_fail, 1);
484 continue;
485 }
486 }
487 }
488
489 static void redo_lazy_relocs()
490 {
491 struct dso *p = lazy_head, *next;
492 lazy_head = 0;
493 for (; p; p=next) {
494 next = p->lazy_next;
495 size_t size = p->lazy_cnt*3*sizeof(size_t);
496 p->lazy_cnt = 0;
497 do_relocs(p, p->lazy, size, 3);
498 if (p->lazy_cnt) {
499 p->lazy_next = lazy_head;
500 lazy_head = p;
501 } else {
502 free(p->lazy);
503 p->lazy = 0;
504 p->lazy_next = 0;
505 }
506 }
507 }
508
509 /* A huge hack: to make up for the wastefulness of shared libraries
510 * needing at least a page of dirty memory even if they have no global
511 * data, we reclaim the gaps at the beginning and end of writable maps
512 * and "donate" them to the heap. */
513
514 static void reclaim(struct dso *dso, size_t start, size_t end)
515 {
516 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
517 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
518 if (start >= end) return;
519 char *base = laddr_pg(dso, start);
520 __malloc_donate(base, base+(end-start));
521 }
522
523 static void reclaim_gaps(struct dso *dso)
524 {
525 Phdr *ph = dso->phdr;
526 size_t phcnt = dso->phnum;
527
528 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
529 if (ph->p_type!=PT_LOAD) continue;
530 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
531 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
532 reclaim(dso, ph->p_vaddr+ph->p_memsz,
533 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
534 }
535 }
536
537 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
538 {
539 static int no_map_fixed;
540 char *q;
541 if (!no_map_fixed) {
542 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
543 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
544 return q;
545 no_map_fixed = 1;
546 }
547 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
548 if (flags & MAP_ANONYMOUS) {
549 memset(p, 0, n);
550 return p;
551 }
552 ssize_t r;
553 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
554 for (q=p; n; q+=r, off+=r, n-=r) {
555 r = read(fd, q, n);
556 if (r < 0 && errno != EINTR) return MAP_FAILED;
557 if (!r) {
558 memset(q, 0, n);
559 break;
560 }
561 }
562 return p;
563 }
564
565 static void unmap_library(struct dso *dso)
566 {
567 if (dso->loadmap) {
568 size_t i;
569 for (i=0; i<dso->loadmap->nsegs; i++) {
570 if (!dso->loadmap->segs[i].p_memsz)
571 continue;
572 munmap((void *)dso->loadmap->segs[i].addr,
573 dso->loadmap->segs[i].p_memsz);
574 }
575 free(dso->loadmap);
576 } else if (dso->map && dso->map_len) {
577 munmap(dso->map, dso->map_len);
578 }
579 }
580
581 static void *map_library(int fd, struct dso *dso)
582 {
583 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
584 void *allocated_buf=0;
585 size_t phsize;
586 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
587 size_t this_min, this_max;
588 size_t nsegs = 0;
589 off_t off_start;
590 Ehdr *eh;
591 Phdr *ph, *ph0;
592 unsigned prot;
593 unsigned char *map=MAP_FAILED, *base;
594 size_t dyn=0;
595 size_t tls_image=0;
596 size_t i;
597
598 ssize_t l = read(fd, buf, sizeof buf);
599 eh = buf;
600 if (l<0) return 0;
601 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
602 goto noexec;
603 phsize = eh->e_phentsize * eh->e_phnum;
604 if (phsize > sizeof buf - sizeof *eh) {
605 allocated_buf = malloc(phsize);
606 if (!allocated_buf) return 0;
607 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
608 if (l < 0) goto error;
609 if (l != phsize) goto noexec;
610 ph = ph0 = allocated_buf;
611 } else if (eh->e_phoff + phsize > l) {
612 l = pread(fd, buf+1, phsize, eh->e_phoff);
613 if (l < 0) goto error;
614 if (l != phsize) goto noexec;
615 ph = ph0 = (void *)(buf + 1);
616 } else {
617 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
618 }
619 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
620 if (ph->p_type == PT_DYNAMIC) {
621 dyn = ph->p_vaddr;
622 } else if (ph->p_type == PT_TLS) {
623 tls_image = ph->p_vaddr;
624 dso->tls.align = ph->p_align;
625 dso->tls.len = ph->p_filesz;
626 dso->tls.size = ph->p_memsz;
627 } else if (ph->p_type == PT_GNU_RELRO) {
628 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
629 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
630 } else if (ph->p_type == PT_GNU_STACK) {
631 if (!runtime && ph->p_memsz > __default_stacksize) {
632 __default_stacksize =
633 ph->p_memsz < DEFAULT_STACK_MAX ?
634 ph->p_memsz : DEFAULT_STACK_MAX;
635 }
636 }
637 if (ph->p_type != PT_LOAD) continue;
638 nsegs++;
639 if (ph->p_vaddr < addr_min) {
640 addr_min = ph->p_vaddr;
641 off_start = ph->p_offset;
642 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
643 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
644 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
645 }
646 if (ph->p_vaddr+ph->p_memsz > addr_max) {
647 addr_max = ph->p_vaddr+ph->p_memsz;
648 }
649 }
650 if (!dyn) goto noexec;
651 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
652 dso->loadmap = calloc(1, sizeof *dso->loadmap
653 + nsegs * sizeof *dso->loadmap->segs);
654 if (!dso->loadmap) goto error;
655 dso->loadmap->nsegs = nsegs;
656 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
657 if (ph->p_type != PT_LOAD) continue;
658 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
659 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
660 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
661 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
662 prot, MAP_PRIVATE,
663 fd, ph->p_offset & -PAGE_SIZE);
664 if (map == MAP_FAILED) {
665 unmap_library(dso);
666 goto error;
667 }
668 dso->loadmap->segs[i].addr = (size_t)map +
669 (ph->p_vaddr & PAGE_SIZE-1);
670 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
671 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
672 i++;
673 if (prot & PROT_WRITE) {
674 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
675 + ph->p_filesz;
676 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
677 size_t pgend = brk + ph->p_memsz - ph->p_filesz
678 + PAGE_SIZE-1 & -PAGE_SIZE;
679 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
680 pgend-pgbrk, prot,
681 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
682 -1, off_start) == MAP_FAILED)
683 goto error;
684 memset(map + brk, 0, pgbrk-brk);
685 }
686 }
687 map = (void *)dso->loadmap->segs[0].addr;
688 map_len = 0;
689 goto done_mapping;
690 }
691 addr_max += PAGE_SIZE-1;
692 addr_max &= -PAGE_SIZE;
693 addr_min &= -PAGE_SIZE;
694 off_start &= -PAGE_SIZE;
695 map_len = addr_max - addr_min + off_start;
696 /* The first time, we map too much, possibly even more than
697 * the length of the file. This is okay because we will not
698 * use the invalid part; we just need to reserve the right
699 * amount of virtual address space to map over later. */
700 map = DL_NOMMU_SUPPORT
701 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
702 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
703 : mmap((void *)addr_min, map_len, prot,
704 MAP_PRIVATE, fd, off_start);
705 if (map==MAP_FAILED) goto error;
706 dso->map = map;
707 dso->map_len = map_len;
708 /* If the loaded file is not relocatable and the requested address is
709 * not available, then the load operation must fail. */
710 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
711 errno = EBUSY;
712 goto error;
713 }
714 base = map - addr_min;
715 dso->phdr = 0;
716 dso->phnum = 0;
717 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
718 if (ph->p_type != PT_LOAD) continue;
719 /* Check if the programs headers are in this load segment, and
720 * if so, record the address for use by dl_iterate_phdr. */
721 if (!dso->phdr && eh->e_phoff >= ph->p_offset
722 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
723 dso->phdr = (void *)(base + ph->p_vaddr
724 + (eh->e_phoff-ph->p_offset));
725 dso->phnum = eh->e_phnum;
726 dso->phentsize = eh->e_phentsize;
727 }
728 this_min = ph->p_vaddr & -PAGE_SIZE;
729 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
730 off_start = ph->p_offset & -PAGE_SIZE;
731 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
732 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
733 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
734 /* Reuse the existing mapping for the lowest-address LOAD */
735 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
736 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
737 goto error;
738 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
739 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
740 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
741 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
742 if (pgbrk-(size_t)base < this_max && mmap_fixed((void *)pgbrk, (size_t)base+this_max-pgbrk, prot, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED)
743 goto error;
744 }
745 }
746 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
747 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
748 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
749 && errno != ENOSYS)
750 goto error;
751 break;
752 }
753 done_mapping:
754 dso->base = base;
755 dso->dynv = laddr(dso, dyn);
756 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
757 free(allocated_buf);
758 return map;
759 noexec:
760 errno = ENOEXEC;
761 error:
762 if (map!=MAP_FAILED) unmap_library(dso);
763 free(allocated_buf);
764 return 0;
765 }
766
767 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
768 {
769 size_t l;
770 int fd;
771 for (;;) {
772 s += strspn(s, ":\n");
773 l = strcspn(s, ":\n");
774 if (l-1 >= INT_MAX) return -1;
775 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
776 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
777 switch (errno) {
778 case ENOENT:
779 case ENOTDIR:
780 case EACCES:
781 case ENAMETOOLONG:
782 break;
783 default:
784 /* Any negative value but -1 will inhibit
785 * futher path search. */
786 return -2;
787 }
788 }
789 s += l;
790 }
791 }
792
793 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
794 {
795 size_t n, l;
796 const char *s, *t, *origin;
797 char *d;
798 if (p->rpath || !p->rpath_orig) return 0;
799 if (!strchr(p->rpath_orig, '$')) {
800 p->rpath = p->rpath_orig;
801 return 0;
802 }
803 n = 0;
804 s = p->rpath_orig;
805 while ((t=strchr(s, '$'))) {
806 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
807 return 0;
808 s = t+1;
809 n++;
810 }
811 if (n > SSIZE_MAX/PATH_MAX) return 0;
812
813 if (p->kernel_mapped) {
814 /* $ORIGIN searches cannot be performed for the main program
815 * when it is suid/sgid/AT_SECURE. This is because the
816 * pathname is under the control of the caller of execve.
817 * For libraries, however, $ORIGIN can be processed safely
818 * since the library's pathname came from a trusted source
819 * (either system paths or a call to dlopen). */
820 if (libc.secure)
821 return 0;
822 l = readlink("/proc/self/exe", buf, buf_size);
823 if (l == -1) switch (errno) {
824 case ENOENT:
825 case ENOTDIR:
826 case EACCES:
827 break;
828 default:
829 return -1;
830 }
831 if (l >= buf_size)
832 return 0;
833 buf[l] = 0;
834 origin = buf;
835 } else {
836 origin = p->name;
837 }
838 t = strrchr(origin, '/');
839 if (t) {
840 l = t-origin;
841 } else {
842 /* Normally p->name will always be an absolute or relative
843 * pathname containing at least one '/' character, but in the
844 * case where ldso was invoked as a command to execute a
845 * program in the working directory, app.name may not. Fix. */
846 origin = ".";
847 l = 1;
848 }
849 /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
850 if (libc.secure && *origin != '/')
851 return 0;
852 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
853 if (!p->rpath) return -1;
854
855 d = p->rpath;
856 s = p->rpath_orig;
857 while ((t=strchr(s, '$'))) {
858 memcpy(d, s, t-s);
859 d += t-s;
860 memcpy(d, origin, l);
861 d += l;
862 /* It was determined previously that the '$' is followed
863 * either by "ORIGIN" or "{ORIGIN}". */
864 s = t + 7 + 2*(t[1]=='{');
865 }
866 strcpy(d, s);
867 return 0;
868 }
869
870 static void decode_dyn(struct dso *p)
871 {
872 size_t dyn[DYN_CNT];
873 decode_vec(p->dynv, dyn, DYN_CNT);
874 p->syms = laddr(p, dyn[DT_SYMTAB]);
875 p->strings = laddr(p, dyn[DT_STRTAB]);
876 if (dyn[0]&(1<<DT_HASH))
877 p->hashtab = laddr(p, dyn[DT_HASH]);
878 if (dyn[0]&(1<<DT_RPATH))
879 p->rpath_orig = p->strings + dyn[DT_RPATH];
880 if (dyn[0]&(1<<DT_RUNPATH))
881 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
882 if (dyn[0]&(1<<DT_PLTGOT))
883 p->got = laddr(p, dyn[DT_PLTGOT]);
884 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
885 p->ghashtab = laddr(p, *dyn);
886 if (search_vec(p->dynv, dyn, DT_VERSYM))
887 p->versym = laddr(p, *dyn);
888 }
889
890 static size_t count_syms(struct dso *p)
891 {
892 if (p->hashtab) return p->hashtab[1];
893
894 size_t nsym, i;
895 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
896 uint32_t *hashval;
897 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
898 if (buckets[i] > nsym)
899 nsym = buckets[i];
900 }
901 if (nsym) {
902 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
903 do nsym++;
904 while (!(*hashval++ & 1));
905 }
906 return nsym;
907 }
908
909 static void *dl_mmap(size_t n)
910 {
911 void *p;
912 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
913 #ifdef SYS_mmap2
914 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
915 #else
916 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
917 #endif
918 return p == MAP_FAILED ? 0 : p;
919 }
920
921 static void makefuncdescs(struct dso *p)
922 {
923 static int self_done;
924 size_t nsym = count_syms(p);
925 size_t i, size = nsym * sizeof(*p->funcdescs);
926
927 if (!self_done) {
928 p->funcdescs = dl_mmap(size);
929 self_done = 1;
930 } else {
931 p->funcdescs = malloc(size);
932 }
933 if (!p->funcdescs) {
934 if (!runtime) a_crash();
935 error("Error allocating function descriptors for %s", p->name);
936 longjmp(*rtld_fail, 1);
937 }
938 for (i=0; i<nsym; i++) {
939 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
940 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
941 p->funcdescs[i].got = p->got;
942 } else {
943 p->funcdescs[i].addr = 0;
944 p->funcdescs[i].got = 0;
945 }
946 }
947 }
948
949 static struct dso *load_library(const char *name, struct dso *needed_by)
950 {
951 char buf[2*NAME_MAX+2];
952 const char *pathname;
953 unsigned char *map;
954 struct dso *p, temp_dso = {0};
955 int fd;
956 struct stat st;
957 size_t alloc_size;
958 int n_th = 0;
959 int is_self = 0;
960
961 if (!*name) {
962 errno = EINVAL;
963 return 0;
964 }
965
966 /* Catch and block attempts to reload the implementation itself */
967 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
968 static const char reserved[] =
969 "c.pthread.rt.m.dl.util.xnet.";
970 const char *rp, *next;
971 for (rp=reserved; *rp; rp=next) {
972 next = strchr(rp, '.') + 1;
973 if (strncmp(name+3, rp, next-rp) == 0)
974 break;
975 }
976 if (*rp) {
977 if (ldd_mode) {
978 /* Track which names have been resolved
979 * and only report each one once. */
980 static unsigned reported;
981 unsigned mask = 1U<<(rp-reserved);
982 if (!(reported & mask)) {
983 reported |= mask;
984 dprintf(1, "\t%s => %s (%p)\n",
985 name, ldso.name,
986 ldso.base);
987 }
988 }
989 is_self = 1;
990 }
991 }
992 if (!strcmp(name, ldso.name)) is_self = 1;
993 if (is_self) {
994 if (!ldso.prev) {
995 tail->next = &ldso;
996 ldso.prev = tail;
997 tail = &ldso;
998 }
999 return &ldso;
1000 }
1001 if (strchr(name, '/')) {
1002 pathname = name;
1003 fd = open(name, O_RDONLY|O_CLOEXEC);
1004 } else {
1005 /* Search for the name to see if it's already loaded */
1006 for (p=head->next; p; p=p->next) {
1007 if (p->shortname && !strcmp(p->shortname, name)) {
1008 return p;
1009 }
1010 }
1011 if (strlen(name) > NAME_MAX) return 0;
1012 fd = -1;
1013 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
1014 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
1015 if (fixup_rpath(p, buf, sizeof buf) < 0)
1016 fd = -2; /* Inhibit further search. */
1017 if (p->rpath)
1018 fd = path_open(name, p->rpath, buf, sizeof buf);
1019 }
1020 if (fd == -1) {
1021 if (!sys_path) {
1022 char *prefix = 0;
1023 size_t prefix_len;
1024 if (ldso.name[0]=='/') {
1025 char *s, *t, *z;
1026 for (s=t=z=ldso.name; *s; s++)
1027 if (*s=='/') z=t, t=s;
1028 prefix_len = z-ldso.name;
1029 if (prefix_len < PATH_MAX)
1030 prefix = ldso.name;
1031 }
1032 if (!prefix) {
1033 prefix = "";
1034 prefix_len = 0;
1035 }
1036 char etc_ldso_path[prefix_len + 1
1037 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1038 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1039 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1040 (int)prefix_len, prefix);
1041 FILE *f = fopen(etc_ldso_path, "rbe");
1042 if (f) {
1043 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1044 free(sys_path);
1045 sys_path = "";
1046 }
1047 fclose(f);
1048 } else if (errno != ENOENT) {
1049 sys_path = "";
1050 }
1051 }
1052 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1053 fd = path_open(name, sys_path, buf, sizeof buf);
1054 }
1055 pathname = buf;
1056 }
1057 if (fd < 0) return 0;
1058 if (fstat(fd, &st) < 0) {
1059 close(fd);
1060 return 0;
1061 }
1062 for (p=head->next; p; p=p->next) {
1063 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1064 /* If this library was previously loaded with a
1065 * pathname but a search found the same inode,
1066 * setup its shortname so it can be found by name. */
1067 if (!p->shortname && pathname != name)
1068 p->shortname = strrchr(p->name, '/')+1;
1069 close(fd);
1070 return p;
1071 }
1072 }
1073 map = noload ? 0 : map_library(fd, &temp_dso);
1074 close(fd);
1075 if (!map) return 0;
1076
1077 /* Avoid the danger of getting two versions of libc mapped into the
1078 * same process when an absolute pathname was used. The symbols
1079 * checked are chosen to catch both musl and glibc, and to avoid
1080 * false positives from interposition-hack libraries. */
1081 decode_dyn(&temp_dso);
1082 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1083 find_sym(&temp_dso, "stdin", 1).sym) {
1084 unmap_library(&temp_dso);
1085 return load_library("libc.so", needed_by);
1086 }
1087 /* Past this point, if we haven't reached runtime yet, ldso has
1088 * committed either to use the mapped library or to abort execution.
1089 * Unmapping is not possible, so we can safely reclaim gaps. */
1090 if (!runtime) reclaim_gaps(&temp_dso);
1091
1092 /* Allocate storage for the new DSO. When there is TLS, this
1093 * storage must include a reservation for all pre-existing
1094 * threads to obtain copies of both the new TLS, and an
1095 * extended DTV capable of storing an additional slot for
1096 * the newly-loaded DSO. */
1097 alloc_size = sizeof *p + strlen(pathname) + 1;
1098 if (runtime && temp_dso.tls.image) {
1099 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1100 + sizeof(void *) * (tls_cnt+3);
1101 n_th = libc.threads_minus_1 + 1;
1102 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1103 else alloc_size += n_th * per_th;
1104 }
1105 p = calloc(1, alloc_size);
1106 if (!p) {
1107 unmap_library(&temp_dso);
1108 return 0;
1109 }
1110 memcpy(p, &temp_dso, sizeof temp_dso);
1111 p->dev = st.st_dev;
1112 p->ino = st.st_ino;
1113 p->needed_by = needed_by;
1114 p->name = p->buf;
1115 p->runtime_loaded = runtime;
1116 strcpy(p->name, pathname);
1117 /* Add a shortname only if name arg was not an explicit pathname. */
1118 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1119 if (p->tls.image) {
1120 p->tls_id = ++tls_cnt;
1121 tls_align = MAXP2(tls_align, p->tls.align);
1122 #ifdef TLS_ABOVE_TP
1123 p->tls.offset = tls_offset + ( (tls_align-1) &
1124 -(tls_offset + (uintptr_t)p->tls.image) );
1125 tls_offset += p->tls.size;
1126 #else
1127 tls_offset += p->tls.size + p->tls.align - 1;
1128 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1129 & (p->tls.align-1);
1130 p->tls.offset = tls_offset;
1131 #endif
1132 p->new_dtv = (void *)(-sizeof(size_t) &
1133 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1134 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1135 if (tls_tail) tls_tail->next = &p->tls;
1136 else libc.tls_head = &p->tls;
1137 tls_tail = &p->tls;
1138 }
1139
1140 tail->next = p;
1141 p->prev = tail;
1142 tail = p;
1143
1144 if (DL_FDPIC) makefuncdescs(p);
1145
1146 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1147
1148 return p;
1149 }
1150
1151 static void load_direct_deps(struct dso *p)
1152 {
1153 size_t i, cnt=0;
1154 if (p->deps) return;
1155 /* For head, all preloads are direct pseudo-dependencies.
1156 * Count and include them now to avoid realloc later. */
1157 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1158 cnt++;
1159 for (i=0; p->dynv[i]; i+=2)
1160 if (p->dynv[i] == DT_NEEDED) cnt++;
1161 p->deps = calloc(cnt+1, sizeof *p->deps);
1162 if (!p->deps) {
1163 error("Error loading dependencies for %s", p->name);
1164 if (runtime) longjmp(*rtld_fail, 1);
1165 }
1166 cnt=0;
1167 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1168 p->deps[cnt++] = q;
1169 for (i=0; p->dynv[i]; i+=2) {
1170 if (p->dynv[i] != DT_NEEDED) continue;
1171 struct dso *dep = load_library(p->strings + p->dynv[i+1], p);
1172 if (!dep) {
1173 error("Error loading shared library %s: %m (needed by %s)",
1174 p->strings + p->dynv[i+1], p->name);
1175 if (runtime) longjmp(*rtld_fail, 1);
1176 continue;
1177 }
1178 p->deps[cnt++] = dep;
1179 }
1180 p->deps[cnt] = 0;
1181 p->ndeps_direct = cnt;
1182 }
1183
1184 static void load_deps(struct dso *p)
1185 {
1186 if (p->deps) return;
1187 for (; p; p=p->next)
1188 load_direct_deps(p);
1189 }
1190
1191 static void extend_bfs_deps(struct dso *p)
1192 {
1193 size_t i, j, cnt, ndeps_all;
1194 struct dso **tmp;
1195
1196 /* Can't use realloc if the original p->deps was allocated at
1197 * program entry and malloc has been replaced. */
1198 int no_realloc = __malloc_replaced && !p->runtime_loaded;
1199
1200 if (p->bfs_built) return;
1201 ndeps_all = p->ndeps_direct;
1202
1203 /* Mark existing (direct) deps so they won't be duplicated. */
1204 for (i=0; p->deps[i]; i++)
1205 p->deps[i]->mark = 1;
1206
1207 /* For each dependency already in the list, copy its list of direct
1208 * dependencies to the list, excluding any items already in the
1209 * list. Note that the list this loop iterates over will grow during
1210 * the loop, but since duplicates are excluded, growth is bounded. */
1211 for (i=0; p->deps[i]; i++) {
1212 struct dso *dep = p->deps[i];
1213 for (j=cnt=0; j<dep->ndeps_direct; j++)
1214 if (!dep->deps[j]->mark) cnt++;
1215 tmp = no_realloc ?
1216 malloc(sizeof(*tmp) * (ndeps_all+cnt+1)) :
1217 realloc(p->deps, sizeof(*tmp) * (ndeps_all+cnt+1));
1218 if (!tmp) {
1219 error("Error recording dependencies for %s", p->name);
1220 if (runtime) longjmp(*rtld_fail, 1);
1221 continue;
1222 }
1223 if (no_realloc) {
1224 memcpy(tmp, p->deps, sizeof(*tmp) * (ndeps_all+1));
1225 no_realloc = 0;
1226 }
1227 p->deps = tmp;
1228 for (j=0; j<dep->ndeps_direct; j++) {
1229 if (dep->deps[j]->mark) continue;
1230 dep->deps[j]->mark = 1;
1231 p->deps[ndeps_all++] = dep->deps[j];
1232 }
1233 p->deps[ndeps_all] = 0;
1234 }
1235 p->bfs_built = 1;
1236 for (p=head; p; p=p->next)
1237 p->mark = 0;
1238 }
1239
1240 static void load_preload(char *s)
1241 {
1242 int tmp;
1243 char *z;
1244 for (z=s; *z; s=z) {
1245 for ( ; *s && (isspace(*s) || *s==':'); s++);
1246 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1247 tmp = *z;
1248 *z = 0;
1249 load_library(s, 0);
1250 *z = tmp;
1251 }
1252 }
1253
1254 static void add_syms(struct dso *p)
1255 {
1256 if (!p->syms_next && syms_tail != p) {
1257 syms_tail->syms_next = p;
1258 syms_tail = p;
1259 }
1260 }
1261
1262 static void revert_syms(struct dso *old_tail)
1263 {
1264 struct dso *p, *next;
1265 /* Chop off the tail of the list of dsos that participate in
1266 * the global symbol table, reverting them to RTLD_LOCAL. */
1267 for (p=old_tail; p; p=next) {
1268 next = p->syms_next;
1269 p->syms_next = 0;
1270 }
1271 syms_tail = old_tail;
1272 }
1273
1274 static void do_mips_relocs(struct dso *p, size_t *got)
1275 {
1276 size_t i, j, rel[2];
1277 unsigned char *base = p->base;
1278 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1279 if (p==&ldso) {
1280 got += i;
1281 } else {
1282 while (i--) *got++ += (size_t)base;
1283 }
1284 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1285 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1286 Sym *sym = p->syms + j;
1287 rel[0] = (unsigned char *)got - base;
1288 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1289 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1290 do_relocs(p, rel, sizeof rel, 2);
1291 }
1292 }
1293
1294 static void reloc_all(struct dso *p)
1295 {
1296 size_t dyn[DYN_CNT];
1297 for (; p; p=p->next) {
1298 if (p->relocated) continue;
1299 decode_vec(p->dynv, dyn, DYN_CNT);
1300 if (NEED_MIPS_GOT_RELOCS)
1301 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1302 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1303 2+(dyn[DT_PLTREL]==DT_RELA));
1304 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1305 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1306
1307 if (head != &ldso && p->relro_start != p->relro_end &&
1308 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1309 && errno != ENOSYS) {
1310 error("Error relocating %s: RELRO protection failed: %m",
1311 p->name);
1312 if (runtime) longjmp(*rtld_fail, 1);
1313 }
1314
1315 p->relocated = 1;
1316 }
1317 }
1318
1319 static void kernel_mapped_dso(struct dso *p)
1320 {
1321 size_t min_addr = -1, max_addr = 0, cnt;
1322 Phdr *ph = p->phdr;
1323 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1324 if (ph->p_type == PT_DYNAMIC) {
1325 p->dynv = laddr(p, ph->p_vaddr);
1326 } else if (ph->p_type == PT_GNU_RELRO) {
1327 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1328 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1329 } else if (ph->p_type == PT_GNU_STACK) {
1330 if (!runtime && ph->p_memsz > __default_stacksize) {
1331 __default_stacksize =
1332 ph->p_memsz < DEFAULT_STACK_MAX ?
1333 ph->p_memsz : DEFAULT_STACK_MAX;
1334 }
1335 }
1336 if (ph->p_type != PT_LOAD) continue;
1337 if (ph->p_vaddr < min_addr)
1338 min_addr = ph->p_vaddr;
1339 if (ph->p_vaddr+ph->p_memsz > max_addr)
1340 max_addr = ph->p_vaddr+ph->p_memsz;
1341 }
1342 min_addr &= -PAGE_SIZE;
1343 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1344 p->map = p->base + min_addr;
1345 p->map_len = max_addr - min_addr;
1346 p->kernel_mapped = 1;
1347 }
1348
1349 void __libc_exit_fini()
1350 {
1351 struct dso *p;
1352 size_t dyn[DYN_CNT];
1353 for (p=fini_head; p; p=p->fini_next) {
1354 if (!p->constructed) continue;
1355 decode_vec(p->dynv, dyn, DYN_CNT);
1356 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1357 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1358 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1359 while (n--) ((void (*)(void))*--fn)();
1360 }
1361 #ifndef NO_LEGACY_INITFINI
1362 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1363 fpaddr(p, dyn[DT_FINI])();
1364 #endif
1365 }
1366 }
1367
1368 static struct dso **queue_ctors(struct dso *dso)
1369 {
1370 size_t cnt, qpos, spos, i;
1371 struct dso *p, **queue, **stack;
1372
1373 if (ldd_mode) return 0;
1374
1375 /* Bound on queue size is the total number of indirect deps.
1376 * If a bfs deps list was built, we can use it. Otherwise,
1377 * bound by the total number of DSOs, which is always safe and
1378 * is reasonable we use it (for main app at startup). */
1379 if (dso->bfs_built) {
1380 for (cnt=0; dso->deps[cnt]; cnt++)
1381 dso->deps[cnt]->mark = 0;
1382 cnt++; /* self, not included in deps */
1383 } else {
1384 for (cnt=0, p=head; p; cnt++, p=p->next)
1385 p->mark = 0;
1386 }
1387 cnt++; /* termination slot */
1388 stack = queue = calloc(cnt, sizeof *queue);
1389
1390 if (!queue) {
1391 error("Error allocating constructor queue: %m\n");
1392 if (runtime) longjmp(*rtld_fail, 1);
1393 return 0;
1394 }
1395
1396 /* Opposite ends of the allocated buffer serve as an output queue
1397 * and a working stack. Setup initial stack with just the argument
1398 * dso and initial queue empty... */
1399 qpos = 0;
1400 spos = cnt;
1401 stack[--spos] = dso;
1402 dso->next_dep = 0;
1403 dso->mark = 1;
1404
1405 /* Then perform pseudo-DFS sort, but ignoring circular deps. */
1406 while (spos<cnt) {
1407 p = stack[spos++];
1408 while (p->next_dep < p->ndeps_direct) {
1409 if (p->deps[p->next_dep]->mark) {
1410 p->next_dep++;
1411 } else {
1412 stack[--spos] = p;
1413 p = p->deps[p->next_dep];
1414 p->next_dep = 0;
1415 p->mark = 1;
1416 }
1417 }
1418 queue[qpos++] = p;
1419 }
1420 queue[qpos] = 0;
1421 for (i=0; i<qpos; i++) queue[i]->mark = 0;
1422
1423 return queue;
1424 }
1425
1426 static void do_init_fini(struct dso **queue)
1427 {
1428 struct dso *p;
1429 size_t dyn[DYN_CNT], i;
1430 int self = __pthread_self()->tid;
1431
1432 pthread_mutex_lock(&init_fini_lock);
1433 for (i=0; (p=queue[i]); i++) {
1434 while (p->ctor_visitor && p->ctor_visitor!=self)
1435 pthread_cond_wait(&ctor_cond, &init_fini_lock);
1436 if (p->ctor_visitor || p->constructed)
1437 continue;
1438 if (p->constructed) continue;
1439 p->ctor_visitor = self;
1440
1441 decode_vec(p->dynv, dyn, DYN_CNT);
1442 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1443 p->fini_next = fini_head;
1444 fini_head = p;
1445 }
1446
1447 pthread_mutex_unlock(&init_fini_lock);
1448
1449 #ifndef NO_LEGACY_INITFINI
1450 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1451 fpaddr(p, dyn[DT_INIT])();
1452 #endif
1453 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1454 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1455 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1456 while (n--) ((void (*)(void))*fn++)();
1457 }
1458
1459 pthread_mutex_lock(&init_fini_lock);
1460 p->ctor_visitor = 0;
1461 p->constructed = 1;
1462 pthread_cond_broadcast(&ctor_cond);
1463 }
1464 pthread_mutex_unlock(&init_fini_lock);
1465 }
1466
1467 void __libc_start_init(void)
1468 {
1469 do_init_fini(main_ctor_queue);
1470 /* This is valid because the queue was allocated after redoing
1471 * relocations with any interposed malloc having taken effect. */
1472 free(main_ctor_queue);
1473 main_ctor_queue = 0;
1474 }
1475
1476 static void dl_debug_state(void)
1477 {
1478 }
1479
1480 weak_alias(dl_debug_state, _dl_debug_state);
1481
1482 void __init_tls(size_t *auxv)
1483 {
1484 }
1485
1486 static void update_tls_size()
1487 {
1488 libc.tls_cnt = tls_cnt;
1489 libc.tls_align = tls_align;
1490 libc.tls_size = ALIGN(
1491 (1+tls_cnt) * sizeof(void *) +
1492 tls_offset +
1493 sizeof(struct pthread) +
1494 tls_align * 2,
1495 tls_align);
1496 }
1497
1498 static void install_new_tls(void)
1499 {
1500 sigset_t set;
1501 pthread_t self = __pthread_self(), td;
1502 struct dso *dtv_provider = container_of(tls_tail, struct dso, tls);
1503 uintptr_t (*newdtv)[tls_cnt+1] = (void *)dtv_provider->new_dtv;
1504 struct dso *p;
1505 size_t i, j;
1506 size_t old_cnt = self->dtv[0];
1507
1508 __block_app_sigs(&set);
1509 __tl_lock();
1510 /* Copy existing dtv contents from all existing threads. */
1511 for (i=0, td=self; !i || td!=self; i++, td=td->next) {
1512 memcpy(newdtv+i, td->dtv,
1513 (old_cnt+1)*sizeof(uintptr_t));
1514 newdtv[i][0] = tls_cnt;
1515 }
1516 /* Install new dtls into the enlarged, uninstalled dtv copies. */
1517 for (p=head; ; p=p->next) {
1518 if (p->tls_id <= old_cnt) continue;
1519 unsigned char *mem = p->new_tls;
1520 for (j=0; j<i; j++) {
1521 unsigned char *new = mem;
1522 new += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1523 & (p->tls.align-1);
1524 memcpy(new, p->tls.image, p->tls.len);
1525 newdtv[j][p->tls_id] =
1526 (uintptr_t)new + DTP_OFFSET;
1527 mem += p->tls.size + p->tls.align;
1528 }
1529 if (p->tls_id == tls_cnt) break;
1530 }
1531
1532 /* Broadcast barrier to ensure contents of new dtv is visible
1533 * if the new dtv pointer is. The __membarrier function has a
1534 * fallback emulation using signals for kernels that lack the
1535 * feature at the syscall level. */
1536
1537 __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED, 0);
1538
1539 /* Install new dtv for each thread. */
1540 for (j=0, td=self; !j || td!=self; j++, td=td->next) {
1541 td->dtv = td->dtv_copy = newdtv[j];
1542 }
1543
1544 __tl_unlock();
1545 __restore_sigs(&set);
1546 }
1547
1548 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1549 * following stage 2 and stage 3 functions via primitive symbolic lookup
1550 * since it does not have access to their addresses to begin with. */
1551
1552 /* Stage 2 of the dynamic linker is called after relative relocations
1553 * have been processed. It can make function calls to static functions
1554 * and access string literals and static data, but cannot use extern
1555 * symbols. Its job is to perform symbolic relocations on the dynamic
1556 * linker itself, but some of the relocations performed may need to be
1557 * replaced later due to copy relocations in the main program. */
1558
1559 hidden void __dls2(unsigned char *base, size_t *sp)
1560 {
1561 if (DL_FDPIC) {
1562 void *p1 = (void *)sp[-2];
1563 void *p2 = (void *)sp[-1];
1564 if (!p1) {
1565 size_t *auxv, aux[AUX_CNT];
1566 for (auxv=sp+1+*sp+1; *auxv; auxv++);
1567 auxv++;
1568 decode_vec(auxv, aux, AUX_CNT);
1569 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1570 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1571 }
1572 app_loadmap = p2 ? p1 : 0;
1573 ldso.loadmap = p2 ? p2 : p1;
1574 ldso.base = laddr(&ldso, 0);
1575 } else {
1576 ldso.base = base;
1577 }
1578 Ehdr *ehdr = (void *)ldso.base;
1579 ldso.name = ldso.shortname = "libc.so";
1580 ldso.phnum = ehdr->e_phnum;
1581 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1582 ldso.phentsize = ehdr->e_phentsize;
1583 kernel_mapped_dso(&ldso);
1584 decode_dyn(&ldso);
1585
1586 if (DL_FDPIC) makefuncdescs(&ldso);
1587
1588 /* Prepare storage for to save clobbered REL addends so they
1589 * can be reused in stage 3. There should be very few. If
1590 * something goes wrong and there are a huge number, abort
1591 * instead of risking stack overflow. */
1592 size_t dyn[DYN_CNT];
1593 decode_vec(ldso.dynv, dyn, DYN_CNT);
1594 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1595 size_t rel_size = dyn[DT_RELSZ];
1596 size_t symbolic_rel_cnt = 0;
1597 apply_addends_to = rel;
1598 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1599 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1600 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1601 size_t addends[symbolic_rel_cnt+1];
1602 saved_addends = addends;
1603
1604 head = &ldso;
1605 reloc_all(&ldso);
1606
1607 ldso.relocated = 0;
1608
1609 /* Call dynamic linker stage-2b, __dls2b, looking it up
1610 * symbolically as a barrier against moving the address
1611 * load across the above relocation processing. */
1612 struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0);
1613 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp);
1614 else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp);
1615 }
1616
1617 /* Stage 2b sets up a valid thread pointer, which requires relocations
1618 * completed in stage 2, and on which stage 3 is permitted to depend.
1619 * This is done as a separate stage, with symbolic lookup as a barrier,
1620 * so that loads of the thread pointer and &errno can be pure/const and
1621 * thereby hoistable. */
1622
1623 _Noreturn void __dls2b(size_t *sp)
1624 {
1625 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1626 * use during dynamic linking. If possible it will also serve as the
1627 * thread pointer at runtime. */
1628 libc.tls_size = sizeof builtin_tls;
1629 libc.tls_align = tls_align;
1630 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1631 a_crash();
1632 }
1633
1634 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1635 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1636 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1637 }
1638
1639 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1640 * fully functional. Its job is to load (if not already loaded) and
1641 * process dependencies and relocations for the main application and
1642 * transfer control to its entry point. */
1643
1644 _Noreturn void __dls3(size_t *sp)
1645 {
1646 static struct dso app, vdso;
1647 size_t aux[AUX_CNT], *auxv;
1648 size_t i;
1649 char *env_preload=0;
1650 char *replace_argv0=0;
1651 size_t vdso_base;
1652 int argc = *sp;
1653 char **argv = (void *)(sp+1);
1654 char **argv_orig = argv;
1655 char **envp = argv+argc+1;
1656
1657 /* Find aux vector just past environ[] and use it to initialize
1658 * global data that may be needed before we can make syscalls. */
1659 __environ = envp;
1660 for (i=argc+1; argv[i]; i++);
1661 libc.auxv = auxv = (void *)(argv+i+1);
1662 decode_vec(auxv, aux, AUX_CNT);
1663 __hwcap = aux[AT_HWCAP];
1664 libc.page_size = aux[AT_PAGESZ];
1665 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1666 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1667
1668 /* Only trust user/env if kernel says we're not suid/sgid */
1669 if (!libc.secure) {
1670 env_path = getenv("LD_LIBRARY_PATH");
1671 env_preload = getenv("LD_PRELOAD");
1672 }
1673
1674 /* If the main program was already loaded by the kernel,
1675 * AT_PHDR will point to some location other than the dynamic
1676 * linker's program headers. */
1677 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1678 size_t interp_off = 0;
1679 size_t tls_image = 0;
1680 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1681 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1682 app.phnum = aux[AT_PHNUM];
1683 app.phentsize = aux[AT_PHENT];
1684 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1685 if (phdr->p_type == PT_PHDR)
1686 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1687 else if (phdr->p_type == PT_INTERP)
1688 interp_off = (size_t)phdr->p_vaddr;
1689 else if (phdr->p_type == PT_TLS) {
1690 tls_image = phdr->p_vaddr;
1691 app.tls.len = phdr->p_filesz;
1692 app.tls.size = phdr->p_memsz;
1693 app.tls.align = phdr->p_align;
1694 }
1695 }
1696 if (DL_FDPIC) app.loadmap = app_loadmap;
1697 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1698 if (interp_off) ldso.name = laddr(&app, interp_off);
1699 if ((aux[0] & (1UL<<AT_EXECFN))
1700 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1701 app.name = (char *)aux[AT_EXECFN];
1702 else
1703 app.name = argv[0];
1704 kernel_mapped_dso(&app);
1705 } else {
1706 int fd;
1707 char *ldname = argv[0];
1708 size_t l = strlen(ldname);
1709 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1710 argv++;
1711 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1712 char *opt = argv[0]+2;
1713 *argv++ = (void *)-1;
1714 if (!*opt) {
1715 break;
1716 } else if (!memcmp(opt, "list", 5)) {
1717 ldd_mode = 1;
1718 } else if (!memcmp(opt, "library-path", 12)) {
1719 if (opt[12]=='=') env_path = opt+13;
1720 else if (opt[12]) *argv = 0;
1721 else if (*argv) env_path = *argv++;
1722 } else if (!memcmp(opt, "preload", 7)) {
1723 if (opt[7]=='=') env_preload = opt+8;
1724 else if (opt[7]) *argv = 0;
1725 else if (*argv) env_preload = *argv++;
1726 } else if (!memcmp(opt, "argv0", 5)) {
1727 if (opt[5]=='=') replace_argv0 = opt+6;
1728 else if (opt[5]) *argv = 0;
1729 else if (*argv) replace_argv0 = *argv++;
1730 } else {
1731 argv[0] = 0;
1732 }
1733 }
1734 argv[-1] = (void *)(argc - (argv-argv_orig));
1735 if (!argv[0]) {
1736 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1737 "Version %s\n"
1738 "Dynamic Program Loader\n"
1739 "Usage: %s [options] [--] pathname%s\n",
1740 __libc_version, ldname,
1741 ldd_mode ? "" : " [args]");
1742 _exit(1);
1743 }
1744 fd = open(argv[0], O_RDONLY);
1745 if (fd < 0) {
1746 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1747 _exit(1);
1748 }
1749 Ehdr *ehdr = (void *)map_library(fd, &app);
1750 if (!ehdr) {
1751 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1752 _exit(1);
1753 }
1754 close(fd);
1755 ldso.name = ldname;
1756 app.name = argv[0];
1757 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1758 /* Find the name that would have been used for the dynamic
1759 * linker had ldd not taken its place. */
1760 if (ldd_mode) {
1761 for (i=0; i<app.phnum; i++) {
1762 if (app.phdr[i].p_type == PT_INTERP)
1763 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1764 }
1765 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1766 }
1767 }
1768 if (app.tls.size) {
1769 libc.tls_head = tls_tail = &app.tls;
1770 app.tls_id = tls_cnt = 1;
1771 #ifdef TLS_ABOVE_TP
1772 app.tls.offset = GAP_ABOVE_TP;
1773 app.tls.offset += -GAP_ABOVE_TP & (app.tls.align-1);
1774 tls_offset = app.tls.offset + app.tls.size
1775 + ( -((uintptr_t)app.tls.image + app.tls.size)
1776 & (app.tls.align-1) );
1777 #else
1778 tls_offset = app.tls.offset = app.tls.size
1779 + ( -((uintptr_t)app.tls.image + app.tls.size)
1780 & (app.tls.align-1) );
1781 #endif
1782 tls_align = MAXP2(tls_align, app.tls.align);
1783 }
1784 decode_dyn(&app);
1785 if (DL_FDPIC) {
1786 makefuncdescs(&app);
1787 if (!app.loadmap) {
1788 app.loadmap = (void *)&app_dummy_loadmap;
1789 app.loadmap->nsegs = 1;
1790 app.loadmap->segs[0].addr = (size_t)app.map;
1791 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1792 - (size_t)app.base;
1793 app.loadmap->segs[0].p_memsz = app.map_len;
1794 }
1795 argv[-3] = (void *)app.loadmap;
1796 }
1797
1798 /* Initial dso chain consists only of the app. */
1799 head = tail = syms_tail = &app;
1800
1801 /* Donate unused parts of app and library mapping to malloc */
1802 reclaim_gaps(&app);
1803 reclaim_gaps(&ldso);
1804
1805 /* Load preload/needed libraries, add symbols to global namespace. */
1806 if (env_preload) load_preload(env_preload);
1807 load_deps(&app);
1808 for (struct dso *p=head; p; p=p->next)
1809 add_syms(p);
1810
1811 /* Attach to vdso, if provided by the kernel, last so that it does
1812 * not become part of the global namespace. */
1813 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1814 Ehdr *ehdr = (void *)vdso_base;
1815 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1816 vdso.phnum = ehdr->e_phnum;
1817 vdso.phentsize = ehdr->e_phentsize;
1818 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1819 if (phdr->p_type == PT_DYNAMIC)
1820 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1821 if (phdr->p_type == PT_LOAD)
1822 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1823 }
1824 vdso.name = "";
1825 vdso.shortname = "linux-gate.so.1";
1826 vdso.relocated = 1;
1827 decode_dyn(&vdso);
1828 vdso.prev = tail;
1829 tail->next = &vdso;
1830 tail = &vdso;
1831 }
1832
1833 for (i=0; app.dynv[i]; i+=2) {
1834 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1835 app.dynv[i+1] = (size_t)&debug;
1836 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1837 size_t *ptr = (size_t *) app.dynv[i+1];
1838 *ptr = (size_t)&debug;
1839 }
1840 }
1841
1842 /* The main program must be relocated LAST since it may contin
1843 * copy relocations which depend on libraries' relocations. */
1844 reloc_all(app.next);
1845 reloc_all(&app);
1846
1847 update_tls_size();
1848 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1849 void *initial_tls = calloc(libc.tls_size, 1);
1850 if (!initial_tls) {
1851 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1852 argv[0], libc.tls_size);
1853 _exit(127);
1854 }
1855 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1856 a_crash();
1857 }
1858 } else {
1859 size_t tmp_tls_size = libc.tls_size;
1860 pthread_t self = __pthread_self();
1861 /* Temporarily set the tls size to the full size of
1862 * builtin_tls so that __copy_tls will use the same layout
1863 * as it did for before. Then check, just to be safe. */
1864 libc.tls_size = sizeof builtin_tls;
1865 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1866 libc.tls_size = tmp_tls_size;
1867 }
1868 static_tls_cnt = tls_cnt;
1869
1870 main_ctor_queue = queue_ctors(&app);
1871
1872 if (ldso_fail) _exit(127);
1873 if (ldd_mode) _exit(0);
1874
1875 /* Determine if malloc was interposed by a replacement implementation
1876 * so that calloc and the memalign family can harden against the
1877 * possibility of incomplete replacement. */
1878 if (find_sym(head, "malloc", 1).dso != &ldso)
1879 __malloc_replaced = 1;
1880
1881 /* Switch to runtime mode: any further failures in the dynamic
1882 * linker are a reportable failure rather than a fatal startup
1883 * error. */
1884 runtime = 1;
1885
1886 debug.ver = 1;
1887 debug.bp = dl_debug_state;
1888 debug.head = head;
1889 debug.base = ldso.base;
1890 debug.state = 0;
1891 _dl_debug_state();
1892
1893 if (replace_argv0) argv[0] = replace_argv0;
1894
1895 errno = 0;
1896
1897 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1898 for(;;);
1899 }
1900
1901 static void prepare_lazy(struct dso *p)
1902 {
1903 size_t dyn[DYN_CNT], n, flags1=0;
1904 decode_vec(p->dynv, dyn, DYN_CNT);
1905 search_vec(p->dynv, &flags1, DT_FLAGS_1);
1906 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1907 return;
1908 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1909 if (NEED_MIPS_GOT_RELOCS) {
1910 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1911 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1912 n += i-j;
1913 }
1914 p->lazy = calloc(n, 3*sizeof(size_t));
1915 if (!p->lazy) {
1916 error("Error preparing lazy relocation for %s: %m", p->name);
1917 longjmp(*rtld_fail, 1);
1918 }
1919 p->lazy_next = lazy_head;
1920 lazy_head = p;
1921 }
1922
1923 void *dlopen(const char *file, int mode)
1924 {
1925 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1926 struct tls_module *orig_tls_tail;
1927 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1928 size_t i;
1929 int cs;
1930 jmp_buf jb;
1931 struct dso **volatile ctor_queue = 0;
1932
1933 if (!file) return head;
1934
1935 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1936 pthread_rwlock_wrlock(&lock);
1937 __inhibit_ptc();
1938
1939 p = 0;
1940 orig_tls_tail = tls_tail;
1941 orig_tls_cnt = tls_cnt;
1942 orig_tls_offset = tls_offset;
1943 orig_tls_align = tls_align;
1944 orig_lazy_head = lazy_head;
1945 orig_syms_tail = syms_tail;
1946 orig_tail = tail;
1947 noload = mode & RTLD_NOLOAD;
1948
1949 rtld_fail = &jb;
1950 if (setjmp(*rtld_fail)) {
1951 /* Clean up anything new that was (partially) loaded */
1952 revert_syms(orig_syms_tail);
1953 for (p=orig_tail->next; p; p=next) {
1954 next = p->next;
1955 while (p->td_index) {
1956 void *tmp = p->td_index->next;
1957 free(p->td_index);
1958 p->td_index = tmp;
1959 }
1960 free(p->funcdescs);
1961 if (p->rpath != p->rpath_orig)
1962 free(p->rpath);
1963 free(p->deps);
1964 unmap_library(p);
1965 free(p);
1966 free(ctor_queue);
1967 }
1968 if (!orig_tls_tail) libc.tls_head = 0;
1969 tls_tail = orig_tls_tail;
1970 if (tls_tail) tls_tail->next = 0;
1971 tls_cnt = orig_tls_cnt;
1972 tls_offset = orig_tls_offset;
1973 tls_align = orig_tls_align;
1974 lazy_head = orig_lazy_head;
1975 tail = orig_tail;
1976 tail->next = 0;
1977 p = 0;
1978 goto end;
1979 } else p = load_library(file, head);
1980
1981 if (!p) {
1982 error(noload ?
1983 "Library %s is not already loaded" :
1984 "Error loading shared library %s: %m",
1985 file);
1986 goto end;
1987 }
1988
1989 /* First load handling */
1990 load_deps(p);
1991 extend_bfs_deps(p);
1992 pthread_mutex_lock(&init_fini_lock);
1993 if (!p->constructed) ctor_queue = queue_ctors(p);
1994 pthread_mutex_unlock(&init_fini_lock);
1995 if (!p->relocated && (mode & RTLD_LAZY)) {
1996 prepare_lazy(p);
1997 for (i=0; p->deps[i]; i++)
1998 if (!p->deps[i]->relocated)
1999 prepare_lazy(p->deps[i]);
2000 }
2001 if (!p->relocated || (mode & RTLD_GLOBAL)) {
2002 /* Make new symbols global, at least temporarily, so we can do
2003 * relocations. If not RTLD_GLOBAL, this is reverted below. */
2004 add_syms(p);
2005 for (i=0; p->deps[i]; i++)
2006 add_syms(p->deps[i]);
2007 }
2008 if (!p->relocated) {
2009 reloc_all(p);
2010 }
2011
2012 /* If RTLD_GLOBAL was not specified, undo any new additions
2013 * to the global symbol table. This is a nop if the library was
2014 * previously loaded and already global. */
2015 if (!(mode & RTLD_GLOBAL))
2016 revert_syms(orig_syms_tail);
2017
2018 /* Processing of deferred lazy relocations must not happen until
2019 * the new libraries are committed; otherwise we could end up with
2020 * relocations resolved to symbol definitions that get removed. */
2021 redo_lazy_relocs();
2022
2023 update_tls_size();
2024 if (tls_cnt != orig_tls_cnt)
2025 install_new_tls();
2026 _dl_debug_state();
2027 orig_tail = tail;
2028 end:
2029 __release_ptc();
2030 if (p) gencnt++;
2031 pthread_rwlock_unlock(&lock);
2032 if (ctor_queue) {
2033 do_init_fini(ctor_queue);
2034 free(ctor_queue);
2035 }
2036 pthread_setcancelstate(cs, 0);
2037 return p;
2038 }
2039
2040 hidden int __dl_invalid_handle(void *h)
2041 {
2042 struct dso *p;
2043 for (p=head; p; p=p->next) if (h==p) return 0;
2044 error("Invalid library handle %p", (void *)h);
2045 return 1;
2046 }
2047
2048 static void *addr2dso(size_t a)
2049 {
2050 struct dso *p;
2051 size_t i;
2052 if (DL_FDPIC) for (p=head; p; p=p->next) {
2053 i = count_syms(p);
2054 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
2055 return p;
2056 }
2057 for (p=head; p; p=p->next) {
2058 if (DL_FDPIC && p->loadmap) {
2059 for (i=0; i<p->loadmap->nsegs; i++) {
2060 if (a-p->loadmap->segs[i].p_vaddr
2061 < p->loadmap->segs[i].p_memsz)
2062 return p;
2063 }
2064 } else {
2065 Phdr *ph = p->phdr;
2066 size_t phcnt = p->phnum;
2067 size_t entsz = p->phentsize;
2068 size_t base = (size_t)p->base;
2069 for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
2070 if (ph->p_type != PT_LOAD) continue;
2071 if (a-base-ph->p_vaddr < ph->p_memsz)
2072 return p;
2073 }
2074 if (a-(size_t)p->map < p->map_len)
2075 return 0;
2076 }
2077 }
2078 return 0;
2079 }
2080
2081 static void *do_dlsym(struct dso *p, const char *s, void *ra)
2082 {
2083 size_t i;
2084 uint32_t h = 0, gh = 0, *ght;
2085 Sym *sym;
2086 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
2087 if (p == RTLD_DEFAULT) {
2088 p = head;
2089 } else if (p == RTLD_NEXT) {
2090 p = addr2dso((size_t)ra);
2091 if (!p) p=head;
2092 p = p->next;
2093 }
2094 struct symdef def = find_sym(p, s, 0);
2095 if (!def.sym) goto failed;
2096 if ((def.sym->st_info&0xf) == STT_TLS)
2097 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
2098 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
2099 return def.dso->funcdescs + (def.sym - def.dso->syms);
2100 return laddr(def.dso, def.sym->st_value);
2101 }
2102 if (__dl_invalid_handle(p))
2103 return 0;
2104 if ((ght = p->ghashtab)) {
2105 gh = gnu_hash(s);
2106 sym = gnu_lookup(gh, ght, p, s);
2107 } else {
2108 h = sysv_hash(s);
2109 sym = sysv_lookup(s, h, p);
2110 }
2111 if (sym && (sym->st_info&0xf) == STT_TLS)
2112 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value-DTP_OFFSET});
2113 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
2114 return p->funcdescs + (sym - p->syms);
2115 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
2116 return laddr(p, sym->st_value);
2117 for (i=0; p->deps[i]; i++) {
2118 if ((ght = p->deps[i]->ghashtab)) {
2119 if (!gh) gh = gnu_hash(s);
2120 sym = gnu_lookup(gh, ght, p->deps[i], s);
2121 } else {
2122 if (!h) h = sysv_hash(s);
2123 sym = sysv_lookup(s, h, p->deps[i]);
2124 }
2125 if (sym && (sym->st_info&0xf) == STT_TLS)
2126 return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value-DTP_OFFSET});
2127 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
2128 return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
2129 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
2130 return laddr(p->deps[i], sym->st_value);
2131 }
2132 failed:
2133 error("Symbol not found: %s", s);
2134 return 0;
2135 }
2136
2137 int dladdr(const void *addr_arg, Dl_info *info)
2138 {
2139 size_t addr = (size_t)addr_arg;
2140 struct dso *p;
2141 Sym *sym, *bestsym;
2142 uint32_t nsym;
2143 char *strings;
2144 size_t best = 0;
2145 size_t besterr = -1;
2146
2147 pthread_rwlock_rdlock(&lock);
2148 p = addr2dso(addr);
2149 pthread_rwlock_unlock(&lock);
2150
2151 if (!p) return 0;
2152
2153 sym = p->syms;
2154 strings = p->strings;
2155 nsym = count_syms(p);
2156
2157 if (DL_FDPIC) {
2158 size_t idx = (addr-(size_t)p->funcdescs)
2159 / sizeof(*p->funcdescs);
2160 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
2161 best = (size_t)(p->funcdescs + idx);
2162 bestsym = sym + idx;
2163 besterr = 0;
2164 }
2165 }
2166
2167 if (!best) for (; nsym; nsym--, sym++) {
2168 if (sym->st_value
2169 && (1<<(sym->st_info&0xf) & OK_TYPES)
2170 && (1<<(sym->st_info>>4) & OK_BINDS)) {
2171 size_t symaddr = (size_t)laddr(p, sym->st_value);
2172 if (symaddr > addr || symaddr <= best)
2173 continue;
2174 best = symaddr;
2175 bestsym = sym;
2176 besterr = addr - symaddr;
2177 if (addr == symaddr)
2178 break;
2179 }
2180 }
2181
2182 if (bestsym && besterr > bestsym->st_size-1) {
2183 best = 0;
2184 bestsym = 0;
2185 }
2186
2187 info->dli_fname = p->name;
2188 info->dli_fbase = p->map;
2189
2190 if (!best) {
2191 info->dli_sname = 0;
2192 info->dli_saddr = 0;
2193 return 1;
2194 }
2195
2196 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2197 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2198 info->dli_sname = strings + bestsym->st_name;
2199 info->dli_saddr = (void *)best;
2200
2201 return 1;
2202 }
2203
2204 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2205 {
2206 void *res;
2207 pthread_rwlock_rdlock(&lock);
2208 res = do_dlsym(p, s, ra);
2209 pthread_rwlock_unlock(&lock);
2210 return res;
2211 }
2212
2213 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2214 {
2215 struct dso *current;
2216 struct dl_phdr_info info;
2217 int ret = 0;
2218 for(current = head; current;) {
2219 info.dlpi_addr = (uintptr_t)current->base;
2220 info.dlpi_name = current->name;
2221 info.dlpi_phdr = current->phdr;
2222 info.dlpi_phnum = current->phnum;
2223 info.dlpi_adds = gencnt;
2224 info.dlpi_subs = 0;
2225 info.dlpi_tls_modid = current->tls_id;
2226 info.dlpi_tls_data = current->tls.image;
2227
2228 ret = (callback)(&info, sizeof (info), data);
2229
2230 if (ret != 0) break;
2231
2232 pthread_rwlock_rdlock(&lock);
2233 current = current->next;
2234 pthread_rwlock_unlock(&lock);
2235 }
2236 return ret;
2237 }
2238
2239 static void error(const char *fmt, ...)
2240 {
2241 va_list ap;
2242 va_start(ap, fmt);
2243 if (!runtime) {
2244 vdprintf(2, fmt, ap);
2245 dprintf(2, "\n");
2246 ldso_fail = 1;
2247 va_end(ap);
2248 return;
2249 }
2250 __dl_vseterr(fmt, ap);
2251 va_end(ap);
2252 }
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