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spare archs without time32 legacy the cost of ioctl fallback conversions
[musl.git] / ldso / dynlink.c
blob7810356bd939d6b810c397587bd48bfbca4e6eb7
1 #define _GNU_SOURCE
2 #define SYSCALL_NO_TLS 1
3 #include <stdio.h>
4 #include <stdlib.h>
5 #include <stdarg.h>
6 #include <stddef.h>
7 #include <string.h>
8 #include <unistd.h>
9 #include <stdint.h>
10 #include <elf.h>
11 #include <sys/mman.h>
12 #include <limits.h>
13 #include <fcntl.h>
14 #include <sys/stat.h>
15 #include <errno.h>
16 #include <link.h>
17 #include <setjmp.h>
18 #include <pthread.h>
19 #include <ctype.h>
20 #include <dlfcn.h>
21 #include <semaphore.h>
22 #include <sys/membarrier.h>
23 #include "pthread_impl.h"
24 #include "libc.h"
25 #include "dynlink.h"
26 #include "malloc_impl.h"
27
28 static void error(const char *, ...);
29
30 #define MAXP2(a,b) (-(-(a)&-(b)))
31 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
32
33 #define container_of(p,t,m) ((t*)((char *)(p)-offsetof(t,m)))
34 #define countof(a) ((sizeof (a))/(sizeof (a)[0]))
35
36 struct debug {
37 int ver;
38 void *head;
39 void (*bp)(void);
40 int state;
41 void *base;
42 };
43
44 struct td_index {
45 size_t args[2];
46 struct td_index *next;
47 };
48
49 struct dso {
50 #if DL_FDPIC
51 struct fdpic_loadmap *loadmap;
52 #else
53 unsigned char *base;
54 #endif
55 char *name;
56 size_t *dynv;
57 struct dso *next, *prev;
58
59 Phdr *phdr;
60 int phnum;
61 size_t phentsize;
62 Sym *syms;
63 Elf_Symndx *hashtab;
64 uint32_t *ghashtab;
65 int16_t *versym;
66 char *strings;
67 struct dso *syms_next, *lazy_next;
68 size_t *lazy, lazy_cnt;
69 unsigned char *map;
70 size_t map_len;
71 dev_t dev;
72 ino_t ino;
73 char relocated;
74 char constructed;
75 char kernel_mapped;
76 char mark;
77 char bfs_built;
78 char runtime_loaded;
79 struct dso **deps, *needed_by;
80 size_t ndeps_direct;
81 size_t next_dep;
82 int ctor_visitor;
83 char *rpath_orig, *rpath;
84 struct tls_module tls;
85 size_t tls_id;
86 size_t relro_start, relro_end;
87 uintptr_t *new_dtv;
88 unsigned char *new_tls;
89 struct td_index *td_index;
90 struct dso *fini_next;
91 char *shortname;
92 #if DL_FDPIC
93 unsigned char *base;
94 #else
95 struct fdpic_loadmap *loadmap;
96 #endif
97 struct funcdesc {
98 void *addr;
99 size_t *got;
100 } *funcdescs;
101 size_t *got;
102 char buf[];
103 };
104
105 struct symdef {
106 Sym *sym;
107 struct dso *dso;
108 };
109
110 static struct builtin_tls {
111 char c;
112 struct pthread pt;
113 void *space[16];
114 } builtin_tls[1];
115 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
116
117 #define ADDEND_LIMIT 4096
118 static size_t *saved_addends, *apply_addends_to;
119
120 static struct dso ldso;
121 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
122 static char *env_path, *sys_path;
123 static unsigned long long gencnt;
124 static int runtime;
125 static int ldd_mode;
126 static int ldso_fail;
127 static int noload;
128 static int shutting_down;
129 static jmp_buf *rtld_fail;
130 static pthread_rwlock_t lock;
131 static struct debug debug;
132 static struct tls_module *tls_tail;
133 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
134 static size_t static_tls_cnt;
135 static pthread_mutex_t init_fini_lock;
136 static pthread_cond_t ctor_cond;
137 static struct dso *builtin_deps[2];
138 static struct dso *const no_deps[1];
139 static struct dso *builtin_ctor_queue[4];
140 static struct dso **main_ctor_queue;
141 static struct fdpic_loadmap *app_loadmap;
142 static struct fdpic_dummy_loadmap app_dummy_loadmap;
143
144 struct debug *_dl_debug_addr = &debug;
145
146 extern hidden int __malloc_replaced;
147
148 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
149
150 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
151
152 weak_alias(__init_array_start, __init_array_end);
153 weak_alias(__fini_array_start, __fini_array_end);
154
155 static int dl_strcmp(const char *l, const char *r)
156 {
157 for (; *l==*r && *l; l++, r++);
158 return *(unsigned char *)l - *(unsigned char *)r;
159 }
160 #define strcmp(l,r) dl_strcmp(l,r)
161
162 /* Compute load address for a virtual address in a given dso. */
163 #if DL_FDPIC
164 static void *laddr(const struct dso *p, size_t v)
165 {
166 size_t j=0;
167 if (!p->loadmap) return p->base + v;
168 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
169 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
170 }
171 static void *laddr_pg(const struct dso *p, size_t v)
172 {
173 size_t j=0;
174 size_t pgsz = PAGE_SIZE;
175 if (!p->loadmap) return p->base + v;
176 for (j=0; ; j++) {
177 size_t a = p->loadmap->segs[j].p_vaddr;
178 size_t b = a + p->loadmap->segs[j].p_memsz;
179 a &= -pgsz;
180 b += pgsz-1;
181 b &= -pgsz;
182 if (v-a<b-a) break;
183 }
184 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
185 }
186 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
187 laddr(p, v), (p)->got })
188 #else
189 #define laddr(p, v) (void *)((p)->base + (v))
190 #define laddr_pg(p, v) laddr(p, v)
191 #define fpaddr(p, v) ((void (*)())laddr(p, v))
192 #endif
193
194 static void decode_vec(size_t *v, size_t *a, size_t cnt)
195 {
196 size_t i;
197 for (i=0; i<cnt; i++) a[i] = 0;
198 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
199 a[0] |= 1UL<<v[0];
200 a[v[0]] = v[1];
201 }
202 }
203
204 static int search_vec(size_t *v, size_t *r, size_t key)
205 {
206 for (; v[0]!=key; v+=2)
207 if (!v[0]) return 0;
208 *r = v[1];
209 return 1;
210 }
211
212 static uint32_t sysv_hash(const char *s0)
213 {
214 const unsigned char *s = (void *)s0;
215 uint_fast32_t h = 0;
216 while (*s) {
217 h = 16*h + *s++;
218 h ^= h>>24 & 0xf0;
219 }
220 return h & 0xfffffff;
221 }
222
223 static uint32_t gnu_hash(const char *s0)
224 {
225 const unsigned char *s = (void *)s0;
226 uint_fast32_t h = 5381;
227 for (; *s; s++)
228 h += h*32 + *s;
229 return h;
230 }
231
232 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
233 {
234 size_t i;
235 Sym *syms = dso->syms;
236 Elf_Symndx *hashtab = dso->hashtab;
237 char *strings = dso->strings;
238 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
239 if ((!dso->versym || dso->versym[i] >= 0)
240 && (!strcmp(s, strings+syms[i].st_name)))
241 return syms+i;
242 }
243 return 0;
244 }
245
246 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
247 {
248 uint32_t nbuckets = hashtab[0];
249 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
250 uint32_t i = buckets[h1 % nbuckets];
251
252 if (!i) return 0;
253
254 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
255
256 for (h1 |= 1; ; i++) {
257 uint32_t h2 = *hashval++;
258 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
259 && !strcmp(s, dso->strings + dso->syms[i].st_name))
260 return dso->syms+i;
261 if (h2 & 1) break;
262 }
263
264 return 0;
265 }
266
267 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
268 {
269 const size_t *bloomwords = (const void *)(hashtab+4);
270 size_t f = bloomwords[fofs & (hashtab[2]-1)];
271 if (!(f & fmask)) return 0;
272
273 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
274 if (!(f & 1)) return 0;
275
276 return gnu_lookup(h1, hashtab, dso, s);
277 }
278
279 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
280 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
281
282 #ifndef ARCH_SYM_REJECT_UND
283 #define ARCH_SYM_REJECT_UND(s) 0
284 #endif
285
286 #if defined(__GNUC__)
287 __attribute__((always_inline))
288 #endif
289 static inline struct symdef find_sym2(struct dso *dso, const char *s, int need_def, int use_deps)
290 {
291 uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
292 size_t ghm = 1ul << gh % (8*sizeof(size_t));
293 struct symdef def = {0};
294 struct dso **deps = use_deps ? dso->deps : 0;
295 for (; dso; dso=use_deps ? *deps++ : dso->syms_next) {
296 Sym *sym;
297 if ((ght = dso->ghashtab)) {
298 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
299 } else {
300 if (!h) h = sysv_hash(s);
301 sym = sysv_lookup(s, h, dso);
302 }
303 if (!sym) continue;
304 if (!sym->st_shndx)
305 if (need_def || (sym->st_info&0xf) == STT_TLS
306 || ARCH_SYM_REJECT_UND(sym))
307 continue;
308 if (!sym->st_value)
309 if ((sym->st_info&0xf) != STT_TLS)
310 continue;
311 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
312 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
313 def.sym = sym;
314 def.dso = dso;
315 break;
316 }
317 return def;
318 }
319
320 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
321 {
322 return find_sym2(dso, s, need_def, 0);
323 }
324
325 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
326 {
327 unsigned char *base = dso->base;
328 Sym *syms = dso->syms;
329 char *strings = dso->strings;
330 Sym *sym;
331 const char *name;
332 void *ctx;
333 int type;
334 int sym_index;
335 struct symdef def;
336 size_t *reloc_addr;
337 size_t sym_val;
338 size_t tls_val;
339 size_t addend;
340 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
341
342 if (dso == &ldso) {
343 /* Only ldso's REL table needs addend saving/reuse. */
344 if (rel == apply_addends_to)
345 reuse_addends = 1;
346 skip_relative = 1;
347 }
348
349 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
350 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
351 type = R_TYPE(rel[1]);
352 if (type == REL_NONE) continue;
353 reloc_addr = laddr(dso, rel[0]);
354
355 if (stride > 2) {
356 addend = rel[2];
357 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
358 addend = 0;
359 } else if (reuse_addends) {
360 /* Save original addend in stage 2 where the dso
361 * chain consists of just ldso; otherwise read back
362 * saved addend since the inline one was clobbered. */
363 if (head==&ldso)
364 saved_addends[save_slot] = *reloc_addr;
365 addend = saved_addends[save_slot++];
366 } else {
367 addend = *reloc_addr;
368 }
369
370 sym_index = R_SYM(rel[1]);
371 if (sym_index) {
372 sym = syms + sym_index;
373 name = strings + sym->st_name;
374 ctx = type==REL_COPY ? head->syms_next : head;
375 def = (sym->st_info>>4) == STB_LOCAL
376 ? (struct symdef){ .dso = dso, .sym = sym }
377 : find_sym(ctx, name, type==REL_PLT);
378 if (!def.sym && (sym->st_shndx != SHN_UNDEF
379 || sym->st_info>>4 != STB_WEAK)) {
380 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
381 dso->lazy[3*dso->lazy_cnt+0] = rel[0];
382 dso->lazy[3*dso->lazy_cnt+1] = rel[1];
383 dso->lazy[3*dso->lazy_cnt+2] = addend;
384 dso->lazy_cnt++;
385 continue;
386 }
387 error("Error relocating %s: %s: symbol not found",
388 dso->name, name);
389 if (runtime) longjmp(*rtld_fail, 1);
390 continue;
391 }
392 } else {
393 sym = 0;
394 def.sym = 0;
395 def.dso = dso;
396 }
397
398 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
399 tls_val = def.sym ? def.sym->st_value : 0;
400
401 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
402 && def.dso->tls_id > static_tls_cnt) {
403 error("Error relocating %s: %s: initial-exec TLS "
404 "resolves to dynamic definition in %s",
405 dso->name, name, def.dso->name);
406 longjmp(*rtld_fail, 1);
407 }
408
409 switch(type) {
410 case REL_NONE:
411 break;
412 case REL_OFFSET:
413 addend -= (size_t)reloc_addr;
414 case REL_SYMBOLIC:
415 case REL_GOT:
416 case REL_PLT:
417 *reloc_addr = sym_val + addend;
418 break;
419 case REL_USYMBOLIC:
420 memcpy(reloc_addr, &(size_t){sym_val + addend}, sizeof(size_t));
421 break;
422 case REL_RELATIVE:
423 *reloc_addr = (size_t)base + addend;
424 break;
425 case REL_SYM_OR_REL:
426 if (sym) *reloc_addr = sym_val + addend;
427 else *reloc_addr = (size_t)base + addend;
428 break;
429 case REL_COPY:
430 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
431 break;
432 case REL_OFFSET32:
433 *(uint32_t *)reloc_addr = sym_val + addend
434 - (size_t)reloc_addr;
435 break;
436 case REL_FUNCDESC:
437 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
438 + (def.sym - def.dso->syms)) : 0;
439 break;
440 case REL_FUNCDESC_VAL:
441 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
442 else *reloc_addr = sym_val;
443 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
444 break;
445 case REL_DTPMOD:
446 *reloc_addr = def.dso->tls_id;
447 break;
448 case REL_DTPOFF:
449 *reloc_addr = tls_val + addend - DTP_OFFSET;
450 break;
451 #ifdef TLS_ABOVE_TP
452 case REL_TPOFF:
453 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
454 break;
455 #else
456 case REL_TPOFF:
457 *reloc_addr = tls_val - def.dso->tls.offset + addend;
458 break;
459 case REL_TPOFF_NEG:
460 *reloc_addr = def.dso->tls.offset - tls_val + addend;
461 break;
462 #endif
463 case REL_TLSDESC:
464 if (stride<3) addend = reloc_addr[1];
465 if (def.dso->tls_id > static_tls_cnt) {
466 struct td_index *new = malloc(sizeof *new);
467 if (!new) {
468 error(
469 "Error relocating %s: cannot allocate TLSDESC for %s",
470 dso->name, sym ? name : "(local)" );
471 longjmp(*rtld_fail, 1);
472 }
473 new->next = dso->td_index;
474 dso->td_index = new;
475 new->args[0] = def.dso->tls_id;
476 new->args[1] = tls_val + addend - DTP_OFFSET;
477 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
478 reloc_addr[1] = (size_t)new;
479 } else {
480 reloc_addr[0] = (size_t)__tlsdesc_static;
481 #ifdef TLS_ABOVE_TP
482 reloc_addr[1] = tls_val + def.dso->tls.offset
483 + TPOFF_K + addend;
484 #else
485 reloc_addr[1] = tls_val - def.dso->tls.offset
486 + addend;
487 #endif
488 }
489 #ifdef TLSDESC_BACKWARDS
490 /* Some archs (32-bit ARM at least) invert the order of
491 * the descriptor members. Fix them up here. */
492 size_t tmp = reloc_addr[0];
493 reloc_addr[0] = reloc_addr[1];
494 reloc_addr[1] = tmp;
495 #endif
496 break;
497 default:
498 error("Error relocating %s: unsupported relocation type %d",
499 dso->name, type);
500 if (runtime) longjmp(*rtld_fail, 1);
501 continue;
502 }
503 }
504 }
505
506 static void redo_lazy_relocs()
507 {
508 struct dso *p = lazy_head, *next;
509 lazy_head = 0;
510 for (; p; p=next) {
511 next = p->lazy_next;
512 size_t size = p->lazy_cnt*3*sizeof(size_t);
513 p->lazy_cnt = 0;
514 do_relocs(p, p->lazy, size, 3);
515 if (p->lazy_cnt) {
516 p->lazy_next = lazy_head;
517 lazy_head = p;
518 } else {
519 free(p->lazy);
520 p->lazy = 0;
521 p->lazy_next = 0;
522 }
523 }
524 }
525
526 /* A huge hack: to make up for the wastefulness of shared libraries
527 * needing at least a page of dirty memory even if they have no global
528 * data, we reclaim the gaps at the beginning and end of writable maps
529 * and "donate" them to the heap. */
530
531 static void reclaim(struct dso *dso, size_t start, size_t end)
532 {
533 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
534 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
535 if (start >= end) return;
536 char *base = laddr_pg(dso, start);
537 __malloc_donate(base, base+(end-start));
538 }
539
540 static void reclaim_gaps(struct dso *dso)
541 {
542 Phdr *ph = dso->phdr;
543 size_t phcnt = dso->phnum;
544
545 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
546 if (ph->p_type!=PT_LOAD) continue;
547 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
548 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
549 reclaim(dso, ph->p_vaddr+ph->p_memsz,
550 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
551 }
552 }
553
554 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
555 {
556 static int no_map_fixed;
557 char *q;
558 if (!no_map_fixed) {
559 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
560 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
561 return q;
562 no_map_fixed = 1;
563 }
564 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
565 if (flags & MAP_ANONYMOUS) {
566 memset(p, 0, n);
567 return p;
568 }
569 ssize_t r;
570 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
571 for (q=p; n; q+=r, off+=r, n-=r) {
572 r = read(fd, q, n);
573 if (r < 0 && errno != EINTR) return MAP_FAILED;
574 if (!r) {
575 memset(q, 0, n);
576 break;
577 }
578 }
579 return p;
580 }
581
582 static void unmap_library(struct dso *dso)
583 {
584 if (dso->loadmap) {
585 size_t i;
586 for (i=0; i<dso->loadmap->nsegs; i++) {
587 if (!dso->loadmap->segs[i].p_memsz)
588 continue;
589 munmap((void *)dso->loadmap->segs[i].addr,
590 dso->loadmap->segs[i].p_memsz);
591 }
592 free(dso->loadmap);
593 } else if (dso->map && dso->map_len) {
594 munmap(dso->map, dso->map_len);
595 }
596 }
597
598 static void *map_library(int fd, struct dso *dso)
599 {
600 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
601 void *allocated_buf=0;
602 size_t phsize;
603 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
604 size_t this_min, this_max;
605 size_t nsegs = 0;
606 off_t off_start;
607 Ehdr *eh;
608 Phdr *ph, *ph0;
609 unsigned prot;
610 unsigned char *map=MAP_FAILED, *base;
611 size_t dyn=0;
612 size_t tls_image=0;
613 size_t i;
614
615 ssize_t l = read(fd, buf, sizeof buf);
616 eh = buf;
617 if (l<0) return 0;
618 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
619 goto noexec;
620 phsize = eh->e_phentsize * eh->e_phnum;
621 if (phsize > sizeof buf - sizeof *eh) {
622 allocated_buf = malloc(phsize);
623 if (!allocated_buf) return 0;
624 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
625 if (l < 0) goto error;
626 if (l != phsize) goto noexec;
627 ph = ph0 = allocated_buf;
628 } else if (eh->e_phoff + phsize > l) {
629 l = pread(fd, buf+1, phsize, eh->e_phoff);
630 if (l < 0) goto error;
631 if (l != phsize) goto noexec;
632 ph = ph0 = (void *)(buf + 1);
633 } else {
634 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
635 }
636 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
637 if (ph->p_type == PT_DYNAMIC) {
638 dyn = ph->p_vaddr;
639 } else if (ph->p_type == PT_TLS) {
640 tls_image = ph->p_vaddr;
641 dso->tls.align = ph->p_align;
642 dso->tls.len = ph->p_filesz;
643 dso->tls.size = ph->p_memsz;
644 } else if (ph->p_type == PT_GNU_RELRO) {
645 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
646 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
647 } else if (ph->p_type == PT_GNU_STACK) {
648 if (!runtime && ph->p_memsz > __default_stacksize) {
649 __default_stacksize =
650 ph->p_memsz < DEFAULT_STACK_MAX ?
651 ph->p_memsz : DEFAULT_STACK_MAX;
652 }
653 }
654 if (ph->p_type != PT_LOAD) continue;
655 nsegs++;
656 if (ph->p_vaddr < addr_min) {
657 addr_min = ph->p_vaddr;
658 off_start = ph->p_offset;
659 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
660 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
661 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
662 }
663 if (ph->p_vaddr+ph->p_memsz > addr_max) {
664 addr_max = ph->p_vaddr+ph->p_memsz;
665 }
666 }
667 if (!dyn) goto noexec;
668 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
669 dso->loadmap = calloc(1, sizeof *dso->loadmap
670 + nsegs * sizeof *dso->loadmap->segs);
671 if (!dso->loadmap) goto error;
672 dso->loadmap->nsegs = nsegs;
673 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
674 if (ph->p_type != PT_LOAD) continue;
675 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
676 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
677 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
678 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
679 prot, MAP_PRIVATE,
680 fd, ph->p_offset & -PAGE_SIZE);
681 if (map == MAP_FAILED) {
682 unmap_library(dso);
683 goto error;
684 }
685 dso->loadmap->segs[i].addr = (size_t)map +
686 (ph->p_vaddr & PAGE_SIZE-1);
687 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
688 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
689 i++;
690 if (prot & PROT_WRITE) {
691 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
692 + ph->p_filesz;
693 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
694 size_t pgend = brk + ph->p_memsz - ph->p_filesz
695 + PAGE_SIZE-1 & -PAGE_SIZE;
696 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
697 pgend-pgbrk, prot,
698 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
699 -1, off_start) == MAP_FAILED)
700 goto error;
701 memset(map + brk, 0, pgbrk-brk);
702 }
703 }
704 map = (void *)dso->loadmap->segs[0].addr;
705 map_len = 0;
706 goto done_mapping;
707 }
708 addr_max += PAGE_SIZE-1;
709 addr_max &= -PAGE_SIZE;
710 addr_min &= -PAGE_SIZE;
711 off_start &= -PAGE_SIZE;
712 map_len = addr_max - addr_min + off_start;
713 /* The first time, we map too much, possibly even more than
714 * the length of the file. This is okay because we will not
715 * use the invalid part; we just need to reserve the right
716 * amount of virtual address space to map over later. */
717 map = DL_NOMMU_SUPPORT
718 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
719 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
720 : mmap((void *)addr_min, map_len, prot,
721 MAP_PRIVATE, fd, off_start);
722 if (map==MAP_FAILED) goto error;
723 dso->map = map;
724 dso->map_len = map_len;
725 /* If the loaded file is not relocatable and the requested address is
726 * not available, then the load operation must fail. */
727 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
728 errno = EBUSY;
729 goto error;
730 }
731 base = map - addr_min;
732 dso->phdr = 0;
733 dso->phnum = 0;
734 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
735 if (ph->p_type != PT_LOAD) continue;
736 /* Check if the programs headers are in this load segment, and
737 * if so, record the address for use by dl_iterate_phdr. */
738 if (!dso->phdr && eh->e_phoff >= ph->p_offset
739 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
740 dso->phdr = (void *)(base + ph->p_vaddr
741 + (eh->e_phoff-ph->p_offset));
742 dso->phnum = eh->e_phnum;
743 dso->phentsize = eh->e_phentsize;
744 }
745 this_min = ph->p_vaddr & -PAGE_SIZE;
746 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
747 off_start = ph->p_offset & -PAGE_SIZE;
748 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
749 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
750 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
751 /* Reuse the existing mapping for the lowest-address LOAD */
752 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
753 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
754 goto error;
755 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
756 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
757 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
758 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
759 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)
760 goto error;
761 }
762 }
763 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
764 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
765 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
766 && errno != ENOSYS)
767 goto error;
768 break;
769 }
770 done_mapping:
771 dso->base = base;
772 dso->dynv = laddr(dso, dyn);
773 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
774 free(allocated_buf);
775 return map;
776 noexec:
777 errno = ENOEXEC;
778 error:
779 if (map!=MAP_FAILED) unmap_library(dso);
780 free(allocated_buf);
781 return 0;
782 }
783
784 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
785 {
786 size_t l;
787 int fd;
788 for (;;) {
789 s += strspn(s, ":\n");
790 l = strcspn(s, ":\n");
791 if (l-1 >= INT_MAX) return -1;
792 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
793 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
794 switch (errno) {
795 case ENOENT:
796 case ENOTDIR:
797 case EACCES:
798 case ENAMETOOLONG:
799 break;
800 default:
801 /* Any negative value but -1 will inhibit
802 * futher path search. */
803 return -2;
804 }
805 }
806 s += l;
807 }
808 }
809
810 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
811 {
812 size_t n, l;
813 const char *s, *t, *origin;
814 char *d;
815 if (p->rpath || !p->rpath_orig) return 0;
816 if (!strchr(p->rpath_orig, '$')) {
817 p->rpath = p->rpath_orig;
818 return 0;
819 }
820 n = 0;
821 s = p->rpath_orig;
822 while ((t=strchr(s, '$'))) {
823 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
824 return 0;
825 s = t+1;
826 n++;
827 }
828 if (n > SSIZE_MAX/PATH_MAX) return 0;
829
830 if (p->kernel_mapped) {
831 /* $ORIGIN searches cannot be performed for the main program
832 * when it is suid/sgid/AT_SECURE. This is because the
833 * pathname is under the control of the caller of execve.
834 * For libraries, however, $ORIGIN can be processed safely
835 * since the library's pathname came from a trusted source
836 * (either system paths or a call to dlopen). */
837 if (libc.secure)
838 return 0;
839 l = readlink("/proc/self/exe", buf, buf_size);
840 if (l == -1) switch (errno) {
841 case ENOENT:
842 case ENOTDIR:
843 case EACCES:
844 break;
845 default:
846 return -1;
847 }
848 if (l >= buf_size)
849 return 0;
850 buf[l] = 0;
851 origin = buf;
852 } else {
853 origin = p->name;
854 }
855 t = strrchr(origin, '/');
856 if (t) {
857 l = t-origin;
858 } else {
859 /* Normally p->name will always be an absolute or relative
860 * pathname containing at least one '/' character, but in the
861 * case where ldso was invoked as a command to execute a
862 * program in the working directory, app.name may not. Fix. */
863 origin = ".";
864 l = 1;
865 }
866 /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
867 if (libc.secure && *origin != '/')
868 return 0;
869 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
870 if (!p->rpath) return -1;
871
872 d = p->rpath;
873 s = p->rpath_orig;
874 while ((t=strchr(s, '$'))) {
875 memcpy(d, s, t-s);
876 d += t-s;
877 memcpy(d, origin, l);
878 d += l;
879 /* It was determined previously that the '$' is followed
880 * either by "ORIGIN" or "{ORIGIN}". */
881 s = t + 7 + 2*(t[1]=='{');
882 }
883 strcpy(d, s);
884 return 0;
885 }
886
887 static void decode_dyn(struct dso *p)
888 {
889 size_t dyn[DYN_CNT];
890 decode_vec(p->dynv, dyn, DYN_CNT);
891 p->syms = laddr(p, dyn[DT_SYMTAB]);
892 p->strings = laddr(p, dyn[DT_STRTAB]);
893 if (dyn[0]&(1<<DT_HASH))
894 p->hashtab = laddr(p, dyn[DT_HASH]);
895 if (dyn[0]&(1<<DT_RPATH))
896 p->rpath_orig = p->strings + dyn[DT_RPATH];
897 if (dyn[0]&(1<<DT_RUNPATH))
898 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
899 if (dyn[0]&(1<<DT_PLTGOT))
900 p->got = laddr(p, dyn[DT_PLTGOT]);
901 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
902 p->ghashtab = laddr(p, *dyn);
903 if (search_vec(p->dynv, dyn, DT_VERSYM))
904 p->versym = laddr(p, *dyn);
905 }
906
907 static size_t count_syms(struct dso *p)
908 {
909 if (p->hashtab) return p->hashtab[1];
910
911 size_t nsym, i;
912 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
913 uint32_t *hashval;
914 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
915 if (buckets[i] > nsym)
916 nsym = buckets[i];
917 }
918 if (nsym) {
919 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
920 do nsym++;
921 while (!(*hashval++ & 1));
922 }
923 return nsym;
924 }
925
926 static void *dl_mmap(size_t n)
927 {
928 void *p;
929 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
930 #ifdef SYS_mmap2
931 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
932 #else
933 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
934 #endif
935 return (unsigned long)p > -4096UL ? 0 : p;
936 }
937
938 static void makefuncdescs(struct dso *p)
939 {
940 static int self_done;
941 size_t nsym = count_syms(p);
942 size_t i, size = nsym * sizeof(*p->funcdescs);
943
944 if (!self_done) {
945 p->funcdescs = dl_mmap(size);
946 self_done = 1;
947 } else {
948 p->funcdescs = malloc(size);
949 }
950 if (!p->funcdescs) {
951 if (!runtime) a_crash();
952 error("Error allocating function descriptors for %s", p->name);
953 longjmp(*rtld_fail, 1);
954 }
955 for (i=0; i<nsym; i++) {
956 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
957 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
958 p->funcdescs[i].got = p->got;
959 } else {
960 p->funcdescs[i].addr = 0;
961 p->funcdescs[i].got = 0;
962 }
963 }
964 }
965
966 static struct dso *load_library(const char *name, struct dso *needed_by)
967 {
968 char buf[2*NAME_MAX+2];
969 const char *pathname;
970 unsigned char *map;
971 struct dso *p, temp_dso = {0};
972 int fd;
973 struct stat st;
974 size_t alloc_size;
975 int n_th = 0;
976 int is_self = 0;
977
978 if (!*name) {
979 errno = EINVAL;
980 return 0;
981 }
982
983 /* Catch and block attempts to reload the implementation itself */
984 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
985 static const char reserved[] =
986 "c.pthread.rt.m.dl.util.xnet.";
987 const char *rp, *next;
988 for (rp=reserved; *rp; rp=next) {
989 next = strchr(rp, '.') + 1;
990 if (strncmp(name+3, rp, next-rp) == 0)
991 break;
992 }
993 if (*rp) {
994 if (ldd_mode) {
995 /* Track which names have been resolved
996 * and only report each one once. */
997 static unsigned reported;
998 unsigned mask = 1U<<(rp-reserved);
999 if (!(reported & mask)) {
1000 reported |= mask;
1001 dprintf(1, "\t%s => %s (%p)\n",
1002 name, ldso.name,
1003 ldso.base);
1004 }
1005 }
1006 is_self = 1;
1007 }
1008 }
1009 if (!strcmp(name, ldso.name)) is_self = 1;
1010 if (is_self) {
1011 if (!ldso.prev) {
1012 tail->next = &ldso;
1013 ldso.prev = tail;
1014 tail = &ldso;
1015 }
1016 return &ldso;
1017 }
1018 if (strchr(name, '/')) {
1019 pathname = name;
1020 fd = open(name, O_RDONLY|O_CLOEXEC);
1021 } else {
1022 /* Search for the name to see if it's already loaded */
1023 for (p=head->next; p; p=p->next) {
1024 if (p->shortname && !strcmp(p->shortname, name)) {
1025 return p;
1026 }
1027 }
1028 if (strlen(name) > NAME_MAX) return 0;
1029 fd = -1;
1030 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
1031 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
1032 if (fixup_rpath(p, buf, sizeof buf) < 0)
1033 fd = -2; /* Inhibit further search. */
1034 if (p->rpath)
1035 fd = path_open(name, p->rpath, buf, sizeof buf);
1036 }
1037 if (fd == -1) {
1038 if (!sys_path) {
1039 char *prefix = 0;
1040 size_t prefix_len;
1041 if (ldso.name[0]=='/') {
1042 char *s, *t, *z;
1043 for (s=t=z=ldso.name; *s; s++)
1044 if (*s=='/') z=t, t=s;
1045 prefix_len = z-ldso.name;
1046 if (prefix_len < PATH_MAX)
1047 prefix = ldso.name;
1048 }
1049 if (!prefix) {
1050 prefix = "";
1051 prefix_len = 0;
1052 }
1053 char etc_ldso_path[prefix_len + 1
1054 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1055 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1056 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1057 (int)prefix_len, prefix);
1058 FILE *f = fopen(etc_ldso_path, "rbe");
1059 if (f) {
1060 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1061 free(sys_path);
1062 sys_path = "";
1063 }
1064 fclose(f);
1065 } else if (errno != ENOENT) {
1066 sys_path = "";
1067 }
1068 }
1069 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1070 fd = path_open(name, sys_path, buf, sizeof buf);
1071 }
1072 pathname = buf;
1073 }
1074 if (fd < 0) return 0;
1075 if (fstat(fd, &st) < 0) {
1076 close(fd);
1077 return 0;
1078 }
1079 for (p=head->next; p; p=p->next) {
1080 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1081 /* If this library was previously loaded with a
1082 * pathname but a search found the same inode,
1083 * setup its shortname so it can be found by name. */
1084 if (!p->shortname && pathname != name)
1085 p->shortname = strrchr(p->name, '/')+1;
1086 close(fd);
1087 return p;
1088 }
1089 }
1090 map = noload ? 0 : map_library(fd, &temp_dso);
1091 close(fd);
1092 if (!map) return 0;
1093
1094 /* Avoid the danger of getting two versions of libc mapped into the
1095 * same process when an absolute pathname was used. The symbols
1096 * checked are chosen to catch both musl and glibc, and to avoid
1097 * false positives from interposition-hack libraries. */
1098 decode_dyn(&temp_dso);
1099 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1100 find_sym(&temp_dso, "stdin", 1).sym) {
1101 unmap_library(&temp_dso);
1102 return load_library("libc.so", needed_by);
1103 }
1104 /* Past this point, if we haven't reached runtime yet, ldso has
1105 * committed either to use the mapped library or to abort execution.
1106 * Unmapping is not possible, so we can safely reclaim gaps. */
1107 if (!runtime) reclaim_gaps(&temp_dso);
1108
1109 /* Allocate storage for the new DSO. When there is TLS, this
1110 * storage must include a reservation for all pre-existing
1111 * threads to obtain copies of both the new TLS, and an
1112 * extended DTV capable of storing an additional slot for
1113 * the newly-loaded DSO. */
1114 alloc_size = sizeof *p + strlen(pathname) + 1;
1115 if (runtime && temp_dso.tls.image) {
1116 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1117 + sizeof(void *) * (tls_cnt+3);
1118 n_th = libc.threads_minus_1 + 1;
1119 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1120 else alloc_size += n_th * per_th;
1121 }
1122 p = calloc(1, alloc_size);
1123 if (!p) {
1124 unmap_library(&temp_dso);
1125 return 0;
1126 }
1127 memcpy(p, &temp_dso, sizeof temp_dso);
1128 p->dev = st.st_dev;
1129 p->ino = st.st_ino;
1130 p->needed_by = needed_by;
1131 p->name = p->buf;
1132 p->runtime_loaded = runtime;
1133 strcpy(p->name, pathname);
1134 /* Add a shortname only if name arg was not an explicit pathname. */
1135 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1136 if (p->tls.image) {
1137 p->tls_id = ++tls_cnt;
1138 tls_align = MAXP2(tls_align, p->tls.align);
1139 #ifdef TLS_ABOVE_TP
1140 p->tls.offset = tls_offset + ( (p->tls.align-1) &
1141 (-tls_offset + (uintptr_t)p->tls.image) );
1142 tls_offset = p->tls.offset + p->tls.size;
1143 #else
1144 tls_offset += p->tls.size + p->tls.align - 1;
1145 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1146 & (p->tls.align-1);
1147 p->tls.offset = tls_offset;
1148 #endif
1149 p->new_dtv = (void *)(-sizeof(size_t) &
1150 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1151 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1152 if (tls_tail) tls_tail->next = &p->tls;
1153 else libc.tls_head = &p->tls;
1154 tls_tail = &p->tls;
1155 }
1156
1157 tail->next = p;
1158 p->prev = tail;
1159 tail = p;
1160
1161 if (DL_FDPIC) makefuncdescs(p);
1162
1163 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1164
1165 return p;
1166 }
1167
1168 static void load_direct_deps(struct dso *p)
1169 {
1170 size_t i, cnt=0;
1171
1172 if (p->deps) return;
1173 /* For head, all preloads are direct pseudo-dependencies.
1174 * Count and include them now to avoid realloc later. */
1175 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1176 cnt++;
1177 for (i=0; p->dynv[i]; i+=2)
1178 if (p->dynv[i] == DT_NEEDED) cnt++;
1179 /* Use builtin buffer for apps with no external deps, to
1180 * preserve property of no runtime failure paths. */
1181 p->deps = (p==head && cnt<2) ? builtin_deps :
1182 calloc(cnt+1, sizeof *p->deps);
1183 if (!p->deps) {
1184 error("Error loading dependencies for %s", p->name);
1185 if (runtime) longjmp(*rtld_fail, 1);
1186 }
1187 cnt=0;
1188 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1189 p->deps[cnt++] = q;
1190 for (i=0; p->dynv[i]; i+=2) {
1191 if (p->dynv[i] != DT_NEEDED) continue;
1192 struct dso *dep = load_library(p->strings + p->dynv[i+1], p);
1193 if (!dep) {
1194 error("Error loading shared library %s: %m (needed by %s)",
1195 p->strings + p->dynv[i+1], p->name);
1196 if (runtime) longjmp(*rtld_fail, 1);
1197 continue;
1198 }
1199 p->deps[cnt++] = dep;
1200 }
1201 p->deps[cnt] = 0;
1202 p->ndeps_direct = cnt;
1203 }
1204
1205 static void load_deps(struct dso *p)
1206 {
1207 if (p->deps) return;
1208 for (; p; p=p->next)
1209 load_direct_deps(p);
1210 }
1211
1212 static void extend_bfs_deps(struct dso *p)
1213 {
1214 size_t i, j, cnt, ndeps_all;
1215 struct dso **tmp;
1216
1217 /* Can't use realloc if the original p->deps was allocated at
1218 * program entry and malloc has been replaced, or if it's
1219 * the builtin non-allocated trivial main program deps array. */
1220 int no_realloc = (__malloc_replaced && !p->runtime_loaded)
1221 || p->deps == builtin_deps;
1222
1223 if (p->bfs_built) return;
1224 ndeps_all = p->ndeps_direct;
1225
1226 /* Mark existing (direct) deps so they won't be duplicated. */
1227 for (i=0; p->deps[i]; i++)
1228 p->deps[i]->mark = 1;
1229
1230 /* For each dependency already in the list, copy its list of direct
1231 * dependencies to the list, excluding any items already in the
1232 * list. Note that the list this loop iterates over will grow during
1233 * the loop, but since duplicates are excluded, growth is bounded. */
1234 for (i=0; p->deps[i]; i++) {
1235 struct dso *dep = p->deps[i];
1236 for (j=cnt=0; j<dep->ndeps_direct; j++)
1237 if (!dep->deps[j]->mark) cnt++;
1238 tmp = no_realloc ?
1239 malloc(sizeof(*tmp) * (ndeps_all+cnt+1)) :
1240 realloc(p->deps, sizeof(*tmp) * (ndeps_all+cnt+1));
1241 if (!tmp) {
1242 error("Error recording dependencies for %s", p->name);
1243 if (runtime) longjmp(*rtld_fail, 1);
1244 continue;
1245 }
1246 if (no_realloc) {
1247 memcpy(tmp, p->deps, sizeof(*tmp) * (ndeps_all+1));
1248 no_realloc = 0;
1249 }
1250 p->deps = tmp;
1251 for (j=0; j<dep->ndeps_direct; j++) {
1252 if (dep->deps[j]->mark) continue;
1253 dep->deps[j]->mark = 1;
1254 p->deps[ndeps_all++] = dep->deps[j];
1255 }
1256 p->deps[ndeps_all] = 0;
1257 }
1258 p->bfs_built = 1;
1259 for (p=head; p; p=p->next)
1260 p->mark = 0;
1261 }
1262
1263 static void load_preload(char *s)
1264 {
1265 int tmp;
1266 char *z;
1267 for (z=s; *z; s=z) {
1268 for ( ; *s && (isspace(*s) || *s==':'); s++);
1269 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1270 tmp = *z;
1271 *z = 0;
1272 load_library(s, 0);
1273 *z = tmp;
1274 }
1275 }
1276
1277 static void add_syms(struct dso *p)
1278 {
1279 if (!p->syms_next && syms_tail != p) {
1280 syms_tail->syms_next = p;
1281 syms_tail = p;
1282 }
1283 }
1284
1285 static void revert_syms(struct dso *old_tail)
1286 {
1287 struct dso *p, *next;
1288 /* Chop off the tail of the list of dsos that participate in
1289 * the global symbol table, reverting them to RTLD_LOCAL. */
1290 for (p=old_tail; p; p=next) {
1291 next = p->syms_next;
1292 p->syms_next = 0;
1293 }
1294 syms_tail = old_tail;
1295 }
1296
1297 static void do_mips_relocs(struct dso *p, size_t *got)
1298 {
1299 size_t i, j, rel[2];
1300 unsigned char *base = p->base;
1301 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1302 if (p==&ldso) {
1303 got += i;
1304 } else {
1305 while (i--) *got++ += (size_t)base;
1306 }
1307 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1308 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1309 Sym *sym = p->syms + j;
1310 rel[0] = (unsigned char *)got - base;
1311 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1312 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1313 do_relocs(p, rel, sizeof rel, 2);
1314 }
1315 }
1316
1317 static void reloc_all(struct dso *p)
1318 {
1319 size_t dyn[DYN_CNT];
1320 for (; p; p=p->next) {
1321 if (p->relocated) continue;
1322 decode_vec(p->dynv, dyn, DYN_CNT);
1323 if (NEED_MIPS_GOT_RELOCS)
1324 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1325 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1326 2+(dyn[DT_PLTREL]==DT_RELA));
1327 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1328 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1329
1330 if (head != &ldso && p->relro_start != p->relro_end &&
1331 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1332 && errno != ENOSYS) {
1333 error("Error relocating %s: RELRO protection failed: %m",
1334 p->name);
1335 if (runtime) longjmp(*rtld_fail, 1);
1336 }
1337
1338 p->relocated = 1;
1339 }
1340 }
1341
1342 static void kernel_mapped_dso(struct dso *p)
1343 {
1344 size_t min_addr = -1, max_addr = 0, cnt;
1345 Phdr *ph = p->phdr;
1346 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1347 if (ph->p_type == PT_DYNAMIC) {
1348 p->dynv = laddr(p, ph->p_vaddr);
1349 } else if (ph->p_type == PT_GNU_RELRO) {
1350 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1351 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1352 } else if (ph->p_type == PT_GNU_STACK) {
1353 if (!runtime && ph->p_memsz > __default_stacksize) {
1354 __default_stacksize =
1355 ph->p_memsz < DEFAULT_STACK_MAX ?
1356 ph->p_memsz : DEFAULT_STACK_MAX;
1357 }
1358 }
1359 if (ph->p_type != PT_LOAD) continue;
1360 if (ph->p_vaddr < min_addr)
1361 min_addr = ph->p_vaddr;
1362 if (ph->p_vaddr+ph->p_memsz > max_addr)
1363 max_addr = ph->p_vaddr+ph->p_memsz;
1364 }
1365 min_addr &= -PAGE_SIZE;
1366 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1367 p->map = p->base + min_addr;
1368 p->map_len = max_addr - min_addr;
1369 p->kernel_mapped = 1;
1370 }
1371
1372 void __libc_exit_fini()
1373 {
1374 struct dso *p;
1375 size_t dyn[DYN_CNT];
1376 int self = __pthread_self()->tid;
1377
1378 /* Take both locks before setting shutting_down, so that
1379 * either lock is sufficient to read its value. The lock
1380 * order matches that in dlopen to avoid deadlock. */
1381 pthread_rwlock_wrlock(&lock);
1382 pthread_mutex_lock(&init_fini_lock);
1383 shutting_down = 1;
1384 pthread_rwlock_unlock(&lock);
1385 for (p=fini_head; p; p=p->fini_next) {
1386 while (p->ctor_visitor && p->ctor_visitor!=self)
1387 pthread_cond_wait(&ctor_cond, &init_fini_lock);
1388 if (!p->constructed) continue;
1389 decode_vec(p->dynv, dyn, DYN_CNT);
1390 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1391 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1392 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1393 while (n--) ((void (*)(void))*--fn)();
1394 }
1395 #ifndef NO_LEGACY_INITFINI
1396 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1397 fpaddr(p, dyn[DT_FINI])();
1398 #endif
1399 }
1400 }
1401
1402 static struct dso **queue_ctors(struct dso *dso)
1403 {
1404 size_t cnt, qpos, spos, i;
1405 struct dso *p, **queue, **stack;
1406
1407 if (ldd_mode) return 0;
1408
1409 /* Bound on queue size is the total number of indirect deps.
1410 * If a bfs deps list was built, we can use it. Otherwise,
1411 * bound by the total number of DSOs, which is always safe and
1412 * is reasonable we use it (for main app at startup). */
1413 if (dso->bfs_built) {
1414 for (cnt=0; dso->deps[cnt]; cnt++)
1415 dso->deps[cnt]->mark = 0;
1416 cnt++; /* self, not included in deps */
1417 } else {
1418 for (cnt=0, p=head; p; cnt++, p=p->next)
1419 p->mark = 0;
1420 }
1421 cnt++; /* termination slot */
1422 if (dso==head && cnt <= countof(builtin_ctor_queue))
1423 queue = builtin_ctor_queue;
1424 else
1425 queue = calloc(cnt, sizeof *queue);
1426
1427 if (!queue) {
1428 error("Error allocating constructor queue: %m\n");
1429 if (runtime) longjmp(*rtld_fail, 1);
1430 return 0;
1431 }
1432
1433 /* Opposite ends of the allocated buffer serve as an output queue
1434 * and a working stack. Setup initial stack with just the argument
1435 * dso and initial queue empty... */
1436 stack = queue;
1437 qpos = 0;
1438 spos = cnt;
1439 stack[--spos] = dso;
1440 dso->next_dep = 0;
1441 dso->mark = 1;
1442
1443 /* Then perform pseudo-DFS sort, but ignoring circular deps. */
1444 while (spos<cnt) {
1445 p = stack[spos++];
1446 while (p->next_dep < p->ndeps_direct) {
1447 if (p->deps[p->next_dep]->mark) {
1448 p->next_dep++;
1449 } else {
1450 stack[--spos] = p;
1451 p = p->deps[p->next_dep];
1452 p->next_dep = 0;
1453 p->mark = 1;
1454 }
1455 }
1456 queue[qpos++] = p;
1457 }
1458 queue[qpos] = 0;
1459 for (i=0; i<qpos; i++) queue[i]->mark = 0;
1460
1461 return queue;
1462 }
1463
1464 static void do_init_fini(struct dso **queue)
1465 {
1466 struct dso *p;
1467 size_t dyn[DYN_CNT], i;
1468 int self = __pthread_self()->tid;
1469
1470 pthread_mutex_lock(&init_fini_lock);
1471 for (i=0; (p=queue[i]); i++) {
1472 while ((p->ctor_visitor && p->ctor_visitor!=self) || shutting_down)
1473 pthread_cond_wait(&ctor_cond, &init_fini_lock);
1474 if (p->ctor_visitor || p->constructed)
1475 continue;
1476 p->ctor_visitor = self;
1477
1478 decode_vec(p->dynv, dyn, DYN_CNT);
1479 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1480 p->fini_next = fini_head;
1481 fini_head = p;
1482 }
1483
1484 pthread_mutex_unlock(&init_fini_lock);
1485
1486 #ifndef NO_LEGACY_INITFINI
1487 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1488 fpaddr(p, dyn[DT_INIT])();
1489 #endif
1490 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1491 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1492 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1493 while (n--) ((void (*)(void))*fn++)();
1494 }
1495
1496 pthread_mutex_lock(&init_fini_lock);
1497 p->ctor_visitor = 0;
1498 p->constructed = 1;
1499 pthread_cond_broadcast(&ctor_cond);
1500 }
1501 pthread_mutex_unlock(&init_fini_lock);
1502 }
1503
1504 void __libc_start_init(void)
1505 {
1506 do_init_fini(main_ctor_queue);
1507 if (!__malloc_replaced && main_ctor_queue != builtin_ctor_queue)
1508 free(main_ctor_queue);
1509 main_ctor_queue = 0;
1510 }
1511
1512 static void dl_debug_state(void)
1513 {
1514 }
1515
1516 weak_alias(dl_debug_state, _dl_debug_state);
1517
1518 void __init_tls(size_t *auxv)
1519 {
1520 }
1521
1522 static void update_tls_size()
1523 {
1524 libc.tls_cnt = tls_cnt;
1525 libc.tls_align = tls_align;
1526 libc.tls_size = ALIGN(
1527 (1+tls_cnt) * sizeof(void *) +
1528 tls_offset +
1529 sizeof(struct pthread) +
1530 tls_align * 2,
1531 tls_align);
1532 }
1533
1534 static void install_new_tls(void)
1535 {
1536 sigset_t set;
1537 pthread_t self = __pthread_self(), td;
1538 struct dso *dtv_provider = container_of(tls_tail, struct dso, tls);
1539 uintptr_t (*newdtv)[tls_cnt+1] = (void *)dtv_provider->new_dtv;
1540 struct dso *p;
1541 size_t i, j;
1542 size_t old_cnt = self->dtv[0];
1543
1544 __block_app_sigs(&set);
1545 __tl_lock();
1546 /* Copy existing dtv contents from all existing threads. */
1547 for (i=0, td=self; !i || td!=self; i++, td=td->next) {
1548 memcpy(newdtv+i, td->dtv,
1549 (old_cnt+1)*sizeof(uintptr_t));
1550 newdtv[i][0] = tls_cnt;
1551 }
1552 /* Install new dtls into the enlarged, uninstalled dtv copies. */
1553 for (p=head; ; p=p->next) {
1554 if (p->tls_id <= old_cnt) continue;
1555 unsigned char *mem = p->new_tls;
1556 for (j=0; j<i; j++) {
1557 unsigned char *new = mem;
1558 new += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1559 & (p->tls.align-1);
1560 memcpy(new, p->tls.image, p->tls.len);
1561 newdtv[j][p->tls_id] =
1562 (uintptr_t)new + DTP_OFFSET;
1563 mem += p->tls.size + p->tls.align;
1564 }
1565 if (p->tls_id == tls_cnt) break;
1566 }
1567
1568 /* Broadcast barrier to ensure contents of new dtv is visible
1569 * if the new dtv pointer is. The __membarrier function has a
1570 * fallback emulation using signals for kernels that lack the
1571 * feature at the syscall level. */
1572
1573 __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED, 0);
1574
1575 /* Install new dtv for each thread. */
1576 for (j=0, td=self; !j || td!=self; j++, td=td->next) {
1577 td->dtv = td->dtv_copy = newdtv[j];
1578 }
1579
1580 __tl_unlock();
1581 __restore_sigs(&set);
1582 }
1583
1584 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1585 * following stage 2 and stage 3 functions via primitive symbolic lookup
1586 * since it does not have access to their addresses to begin with. */
1587
1588 /* Stage 2 of the dynamic linker is called after relative relocations
1589 * have been processed. It can make function calls to static functions
1590 * and access string literals and static data, but cannot use extern
1591 * symbols. Its job is to perform symbolic relocations on the dynamic
1592 * linker itself, but some of the relocations performed may need to be
1593 * replaced later due to copy relocations in the main program. */
1594
1595 hidden void __dls2(unsigned char *base, size_t *sp)
1596 {
1597 if (DL_FDPIC) {
1598 void *p1 = (void *)sp[-2];
1599 void *p2 = (void *)sp[-1];
1600 if (!p1) {
1601 size_t *auxv, aux[AUX_CNT];
1602 for (auxv=sp+1+*sp+1; *auxv; auxv++);
1603 auxv++;
1604 decode_vec(auxv, aux, AUX_CNT);
1605 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1606 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1607 }
1608 app_loadmap = p2 ? p1 : 0;
1609 ldso.loadmap = p2 ? p2 : p1;
1610 ldso.base = laddr(&ldso, 0);
1611 } else {
1612 ldso.base = base;
1613 }
1614 Ehdr *ehdr = (void *)ldso.base;
1615 ldso.name = ldso.shortname = "libc.so";
1616 ldso.phnum = ehdr->e_phnum;
1617 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1618 ldso.phentsize = ehdr->e_phentsize;
1619 kernel_mapped_dso(&ldso);
1620 decode_dyn(&ldso);
1621
1622 if (DL_FDPIC) makefuncdescs(&ldso);
1623
1624 /* Prepare storage for to save clobbered REL addends so they
1625 * can be reused in stage 3. There should be very few. If
1626 * something goes wrong and there are a huge number, abort
1627 * instead of risking stack overflow. */
1628 size_t dyn[DYN_CNT];
1629 decode_vec(ldso.dynv, dyn, DYN_CNT);
1630 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1631 size_t rel_size = dyn[DT_RELSZ];
1632 size_t symbolic_rel_cnt = 0;
1633 apply_addends_to = rel;
1634 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1635 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1636 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1637 size_t addends[symbolic_rel_cnt+1];
1638 saved_addends = addends;
1639
1640 head = &ldso;
1641 reloc_all(&ldso);
1642
1643 ldso.relocated = 0;
1644
1645 /* Call dynamic linker stage-2b, __dls2b, looking it up
1646 * symbolically as a barrier against moving the address
1647 * load across the above relocation processing. */
1648 struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0);
1649 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp);
1650 else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp);
1651 }
1652
1653 /* Stage 2b sets up a valid thread pointer, which requires relocations
1654 * completed in stage 2, and on which stage 3 is permitted to depend.
1655 * This is done as a separate stage, with symbolic lookup as a barrier,
1656 * so that loads of the thread pointer and &errno can be pure/const and
1657 * thereby hoistable. */
1658
1659 void __dls2b(size_t *sp)
1660 {
1661 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1662 * use during dynamic linking. If possible it will also serve as the
1663 * thread pointer at runtime. */
1664 libc.tls_size = sizeof builtin_tls;
1665 libc.tls_align = tls_align;
1666 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1667 a_crash();
1668 }
1669
1670 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1671 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1672 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1673 }
1674
1675 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1676 * fully functional. Its job is to load (if not already loaded) and
1677 * process dependencies and relocations for the main application and
1678 * transfer control to its entry point. */
1679
1680 void __dls3(size_t *sp)
1681 {
1682 static struct dso app, vdso;
1683 size_t aux[AUX_CNT], *auxv;
1684 size_t i;
1685 char *env_preload=0;
1686 char *replace_argv0=0;
1687 size_t vdso_base;
1688 int argc = *sp;
1689 char **argv = (void *)(sp+1);
1690 char **argv_orig = argv;
1691 char **envp = argv+argc+1;
1692
1693 /* Find aux vector just past environ[] and use it to initialize
1694 * global data that may be needed before we can make syscalls. */
1695 __environ = envp;
1696 for (i=argc+1; argv[i]; i++);
1697 libc.auxv = auxv = (void *)(argv+i+1);
1698 decode_vec(auxv, aux, AUX_CNT);
1699 __hwcap = aux[AT_HWCAP];
1700 search_vec(auxv, &__sysinfo, AT_SYSINFO);
1701 __pthread_self()->sysinfo = __sysinfo;
1702 libc.page_size = aux[AT_PAGESZ];
1703 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1704 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1705
1706 /* Only trust user/env if kernel says we're not suid/sgid */
1707 if (!libc.secure) {
1708 env_path = getenv("LD_LIBRARY_PATH");
1709 env_preload = getenv("LD_PRELOAD");
1710 }
1711
1712 /* If the main program was already loaded by the kernel,
1713 * AT_PHDR will point to some location other than the dynamic
1714 * linker's program headers. */
1715 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1716 size_t interp_off = 0;
1717 size_t tls_image = 0;
1718 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1719 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1720 app.phnum = aux[AT_PHNUM];
1721 app.phentsize = aux[AT_PHENT];
1722 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1723 if (phdr->p_type == PT_PHDR)
1724 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1725 else if (phdr->p_type == PT_INTERP)
1726 interp_off = (size_t)phdr->p_vaddr;
1727 else if (phdr->p_type == PT_TLS) {
1728 tls_image = phdr->p_vaddr;
1729 app.tls.len = phdr->p_filesz;
1730 app.tls.size = phdr->p_memsz;
1731 app.tls.align = phdr->p_align;
1732 }
1733 }
1734 if (DL_FDPIC) app.loadmap = app_loadmap;
1735 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1736 if (interp_off) ldso.name = laddr(&app, interp_off);
1737 if ((aux[0] & (1UL<<AT_EXECFN))
1738 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1739 app.name = (char *)aux[AT_EXECFN];
1740 else
1741 app.name = argv[0];
1742 kernel_mapped_dso(&app);
1743 } else {
1744 int fd;
1745 char *ldname = argv[0];
1746 size_t l = strlen(ldname);
1747 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1748 argv++;
1749 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1750 char *opt = argv[0]+2;
1751 *argv++ = (void *)-1;
1752 if (!*opt) {
1753 break;
1754 } else if (!memcmp(opt, "list", 5)) {
1755 ldd_mode = 1;
1756 } else if (!memcmp(opt, "library-path", 12)) {
1757 if (opt[12]=='=') env_path = opt+13;
1758 else if (opt[12]) *argv = 0;
1759 else if (*argv) env_path = *argv++;
1760 } else if (!memcmp(opt, "preload", 7)) {
1761 if (opt[7]=='=') env_preload = opt+8;
1762 else if (opt[7]) *argv = 0;
1763 else if (*argv) env_preload = *argv++;
1764 } else if (!memcmp(opt, "argv0", 5)) {
1765 if (opt[5]=='=') replace_argv0 = opt+6;
1766 else if (opt[5]) *argv = 0;
1767 else if (*argv) replace_argv0 = *argv++;
1768 } else {
1769 argv[0] = 0;
1770 }
1771 }
1772 argv[-1] = (void *)(argc - (argv-argv_orig));
1773 if (!argv[0]) {
1774 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1775 "Version %s\n"
1776 "Dynamic Program Loader\n"
1777 "Usage: %s [options] [--] pathname%s\n",
1778 __libc_version, ldname,
1779 ldd_mode ? "" : " [args]");
1780 _exit(1);
1781 }
1782 fd = open(argv[0], O_RDONLY);
1783 if (fd < 0) {
1784 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1785 _exit(1);
1786 }
1787 Ehdr *ehdr = (void *)map_library(fd, &app);
1788 if (!ehdr) {
1789 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1790 _exit(1);
1791 }
1792 close(fd);
1793 ldso.name = ldname;
1794 app.name = argv[0];
1795 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1796 /* Find the name that would have been used for the dynamic
1797 * linker had ldd not taken its place. */
1798 if (ldd_mode) {
1799 for (i=0; i<app.phnum; i++) {
1800 if (app.phdr[i].p_type == PT_INTERP)
1801 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1802 }
1803 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1804 }
1805 }
1806 if (app.tls.size) {
1807 libc.tls_head = tls_tail = &app.tls;
1808 app.tls_id = tls_cnt = 1;
1809 #ifdef TLS_ABOVE_TP
1810 app.tls.offset = GAP_ABOVE_TP;
1811 app.tls.offset += (-GAP_ABOVE_TP + (uintptr_t)app.tls.image)
1812 & (app.tls.align-1);
1813 tls_offset = app.tls.offset + app.tls.size;
1814 #else
1815 tls_offset = app.tls.offset = app.tls.size
1816 + ( -((uintptr_t)app.tls.image + app.tls.size)
1817 & (app.tls.align-1) );
1818 #endif
1819 tls_align = MAXP2(tls_align, app.tls.align);
1820 }
1821 decode_dyn(&app);
1822 if (DL_FDPIC) {
1823 makefuncdescs(&app);
1824 if (!app.loadmap) {
1825 app.loadmap = (void *)&app_dummy_loadmap;
1826 app.loadmap->nsegs = 1;
1827 app.loadmap->segs[0].addr = (size_t)app.map;
1828 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1829 - (size_t)app.base;
1830 app.loadmap->segs[0].p_memsz = app.map_len;
1831 }
1832 argv[-3] = (void *)app.loadmap;
1833 }
1834
1835 /* Initial dso chain consists only of the app. */
1836 head = tail = syms_tail = &app;
1837
1838 /* Donate unused parts of app and library mapping to malloc */
1839 reclaim_gaps(&app);
1840 reclaim_gaps(&ldso);
1841
1842 /* Load preload/needed libraries, add symbols to global namespace. */
1843 ldso.deps = (struct dso **)no_deps;
1844 if (env_preload) load_preload(env_preload);
1845 load_deps(&app);
1846 for (struct dso *p=head; p; p=p->next)
1847 add_syms(p);
1848
1849 /* Attach to vdso, if provided by the kernel, last so that it does
1850 * not become part of the global namespace. */
1851 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1852 Ehdr *ehdr = (void *)vdso_base;
1853 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1854 vdso.phnum = ehdr->e_phnum;
1855 vdso.phentsize = ehdr->e_phentsize;
1856 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1857 if (phdr->p_type == PT_DYNAMIC)
1858 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1859 if (phdr->p_type == PT_LOAD)
1860 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1861 }
1862 vdso.name = "";
1863 vdso.shortname = "linux-gate.so.1";
1864 vdso.relocated = 1;
1865 vdso.deps = (struct dso **)no_deps;
1866 decode_dyn(&vdso);
1867 vdso.prev = tail;
1868 tail->next = &vdso;
1869 tail = &vdso;
1870 }
1871
1872 for (i=0; app.dynv[i]; i+=2) {
1873 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1874 app.dynv[i+1] = (size_t)&debug;
1875 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1876 size_t *ptr = (size_t *) app.dynv[i+1];
1877 *ptr = (size_t)&debug;
1878 }
1879 }
1880
1881 /* This must be done before final relocations, since it calls
1882 * malloc, which may be provided by the application. Calling any
1883 * application code prior to the jump to its entry point is not
1884 * valid in our model and does not work with FDPIC, where there
1885 * are additional relocation-like fixups that only the entry point
1886 * code can see to perform. */
1887 main_ctor_queue = queue_ctors(&app);
1888
1889 /* Initial TLS must also be allocated before final relocations
1890 * might result in calloc being a call to application code. */
1891 update_tls_size();
1892 void *initial_tls = builtin_tls;
1893 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1894 initial_tls = calloc(libc.tls_size, 1);
1895 if (!initial_tls) {
1896 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1897 argv[0], libc.tls_size);
1898 _exit(127);
1899 }
1900 }
1901 static_tls_cnt = tls_cnt;
1902
1903 /* The main program must be relocated LAST since it may contain
1904 * copy relocations which depend on libraries' relocations. */
1905 reloc_all(app.next);
1906 reloc_all(&app);
1907
1908 /* Actual copying to new TLS needs to happen after relocations,
1909 * since the TLS images might have contained relocated addresses. */
1910 if (initial_tls != builtin_tls) {
1911 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1912 a_crash();
1913 }
1914 } else {
1915 size_t tmp_tls_size = libc.tls_size;
1916 pthread_t self = __pthread_self();
1917 /* Temporarily set the tls size to the full size of
1918 * builtin_tls so that __copy_tls will use the same layout
1919 * as it did for before. Then check, just to be safe. */
1920 libc.tls_size = sizeof builtin_tls;
1921 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1922 libc.tls_size = tmp_tls_size;
1923 }
1924
1925 if (ldso_fail) _exit(127);
1926 if (ldd_mode) _exit(0);
1927
1928 /* Determine if malloc was interposed by a replacement implementation
1929 * so that calloc and the memalign family can harden against the
1930 * possibility of incomplete replacement. */
1931 if (find_sym(head, "malloc", 1).dso != &ldso)
1932 __malloc_replaced = 1;
1933
1934 /* Switch to runtime mode: any further failures in the dynamic
1935 * linker are a reportable failure rather than a fatal startup
1936 * error. */
1937 runtime = 1;
1938
1939 debug.ver = 1;
1940 debug.bp = dl_debug_state;
1941 debug.head = head;
1942 debug.base = ldso.base;
1943 debug.state = 0;
1944 _dl_debug_state();
1945
1946 if (replace_argv0) argv[0] = replace_argv0;
1947
1948 errno = 0;
1949
1950 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1951 for(;;);
1952 }
1953
1954 static void prepare_lazy(struct dso *p)
1955 {
1956 size_t dyn[DYN_CNT], n, flags1=0;
1957 decode_vec(p->dynv, dyn, DYN_CNT);
1958 search_vec(p->dynv, &flags1, DT_FLAGS_1);
1959 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1960 return;
1961 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1962 if (NEED_MIPS_GOT_RELOCS) {
1963 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1964 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1965 n += i-j;
1966 }
1967 p->lazy = calloc(n, 3*sizeof(size_t));
1968 if (!p->lazy) {
1969 error("Error preparing lazy relocation for %s: %m", p->name);
1970 longjmp(*rtld_fail, 1);
1971 }
1972 p->lazy_next = lazy_head;
1973 lazy_head = p;
1974 }
1975
1976 void *dlopen(const char *file, int mode)
1977 {
1978 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1979 struct tls_module *orig_tls_tail;
1980 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1981 size_t i;
1982 int cs;
1983 jmp_buf jb;
1984 struct dso **volatile ctor_queue = 0;
1985
1986 if (!file) return head;
1987
1988 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1989 pthread_rwlock_wrlock(&lock);
1990 __inhibit_ptc();
1991
1992 p = 0;
1993 if (shutting_down) {
1994 error("Cannot dlopen while program is exiting.");
1995 goto end;
1996 }
1997 orig_tls_tail = tls_tail;
1998 orig_tls_cnt = tls_cnt;
1999 orig_tls_offset = tls_offset;
2000 orig_tls_align = tls_align;
2001 orig_lazy_head = lazy_head;
2002 orig_syms_tail = syms_tail;
2003 orig_tail = tail;
2004 noload = mode & RTLD_NOLOAD;
2005
2006 rtld_fail = &jb;
2007 if (setjmp(*rtld_fail)) {
2008 /* Clean up anything new that was (partially) loaded */
2009 revert_syms(orig_syms_tail);
2010 for (p=orig_tail->next; p; p=next) {
2011 next = p->next;
2012 while (p->td_index) {
2013 void *tmp = p->td_index->next;
2014 free(p->td_index);
2015 p->td_index = tmp;
2016 }
2017 free(p->funcdescs);
2018 if (p->rpath != p->rpath_orig)
2019 free(p->rpath);
2020 free(p->deps);
2021 unmap_library(p);
2022 free(p);
2023 }
2024 free(ctor_queue);
2025 ctor_queue = 0;
2026 if (!orig_tls_tail) libc.tls_head = 0;
2027 tls_tail = orig_tls_tail;
2028 if (tls_tail) tls_tail->next = 0;
2029 tls_cnt = orig_tls_cnt;
2030 tls_offset = orig_tls_offset;
2031 tls_align = orig_tls_align;
2032 lazy_head = orig_lazy_head;
2033 tail = orig_tail;
2034 tail->next = 0;
2035 p = 0;
2036 goto end;
2037 } else p = load_library(file, head);
2038
2039 if (!p) {
2040 error(noload ?
2041 "Library %s is not already loaded" :
2042 "Error loading shared library %s: %m",
2043 file);
2044 goto end;
2045 }
2046
2047 /* First load handling */
2048 load_deps(p);
2049 extend_bfs_deps(p);
2050 pthread_mutex_lock(&init_fini_lock);
2051 if (!p->constructed) ctor_queue = queue_ctors(p);
2052 pthread_mutex_unlock(&init_fini_lock);
2053 if (!p->relocated && (mode & RTLD_LAZY)) {
2054 prepare_lazy(p);
2055 for (i=0; p->deps[i]; i++)
2056 if (!p->deps[i]->relocated)
2057 prepare_lazy(p->deps[i]);
2058 }
2059 if (!p->relocated || (mode & RTLD_GLOBAL)) {
2060 /* Make new symbols global, at least temporarily, so we can do
2061 * relocations. If not RTLD_GLOBAL, this is reverted below. */
2062 add_syms(p);
2063 for (i=0; p->deps[i]; i++)
2064 add_syms(p->deps[i]);
2065 }
2066 if (!p->relocated) {
2067 reloc_all(p);
2068 }
2069
2070 /* If RTLD_GLOBAL was not specified, undo any new additions
2071 * to the global symbol table. This is a nop if the library was
2072 * previously loaded and already global. */
2073 if (!(mode & RTLD_GLOBAL))
2074 revert_syms(orig_syms_tail);
2075
2076 /* Processing of deferred lazy relocations must not happen until
2077 * the new libraries are committed; otherwise we could end up with
2078 * relocations resolved to symbol definitions that get removed. */
2079 redo_lazy_relocs();
2080
2081 update_tls_size();
2082 if (tls_cnt != orig_tls_cnt)
2083 install_new_tls();
2084 _dl_debug_state();
2085 orig_tail = tail;
2086 end:
2087 __release_ptc();
2088 if (p) gencnt++;
2089 pthread_rwlock_unlock(&lock);
2090 if (ctor_queue) {
2091 do_init_fini(ctor_queue);
2092 free(ctor_queue);
2093 }
2094 pthread_setcancelstate(cs, 0);
2095 return p;
2096 }
2097
2098 hidden int __dl_invalid_handle(void *h)
2099 {
2100 struct dso *p;
2101 for (p=head; p; p=p->next) if (h==p) return 0;
2102 error("Invalid library handle %p", (void *)h);
2103 return 1;
2104 }
2105
2106 static void *addr2dso(size_t a)
2107 {
2108 struct dso *p;
2109 size_t i;
2110 if (DL_FDPIC) for (p=head; p; p=p->next) {
2111 i = count_syms(p);
2112 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
2113 return p;
2114 }
2115 for (p=head; p; p=p->next) {
2116 if (DL_FDPIC && p->loadmap) {
2117 for (i=0; i<p->loadmap->nsegs; i++) {
2118 if (a-p->loadmap->segs[i].p_vaddr
2119 < p->loadmap->segs[i].p_memsz)
2120 return p;
2121 }
2122 } else {
2123 Phdr *ph = p->phdr;
2124 size_t phcnt = p->phnum;
2125 size_t entsz = p->phentsize;
2126 size_t base = (size_t)p->base;
2127 for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
2128 if (ph->p_type != PT_LOAD) continue;
2129 if (a-base-ph->p_vaddr < ph->p_memsz)
2130 return p;
2131 }
2132 if (a-(size_t)p->map < p->map_len)
2133 return 0;
2134 }
2135 }
2136 return 0;
2137 }
2138
2139 static void *do_dlsym(struct dso *p, const char *s, void *ra)
2140 {
2141 int use_deps = 0;
2142 if (p == head || p == RTLD_DEFAULT) {
2143 p = head;
2144 } else if (p == RTLD_NEXT) {
2145 p = addr2dso((size_t)ra);
2146 if (!p) p=head;
2147 p = p->next;
2148 } else if (__dl_invalid_handle(p)) {
2149 return 0;
2150 } else
2151 use_deps = 1;
2152 struct symdef def = find_sym2(p, s, 0, use_deps);
2153 if (!def.sym) {
2154 error("Symbol not found: %s", s);
2155 return 0;
2156 }
2157 if ((def.sym->st_info&0xf) == STT_TLS)
2158 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
2159 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
2160 return def.dso->funcdescs + (def.sym - def.dso->syms);
2161 return laddr(def.dso, def.sym->st_value);
2162 }
2163
2164 int dladdr(const void *addr_arg, Dl_info *info)
2165 {
2166 size_t addr = (size_t)addr_arg;
2167 struct dso *p;
2168 Sym *sym, *bestsym;
2169 uint32_t nsym;
2170 char *strings;
2171 size_t best = 0;
2172 size_t besterr = -1;
2173
2174 pthread_rwlock_rdlock(&lock);
2175 p = addr2dso(addr);
2176 pthread_rwlock_unlock(&lock);
2177
2178 if (!p) return 0;
2179
2180 sym = p->syms;
2181 strings = p->strings;
2182 nsym = count_syms(p);
2183
2184 if (DL_FDPIC) {
2185 size_t idx = (addr-(size_t)p->funcdescs)
2186 / sizeof(*p->funcdescs);
2187 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
2188 best = (size_t)(p->funcdescs + idx);
2189 bestsym = sym + idx;
2190 besterr = 0;
2191 }
2192 }
2193
2194 if (!best) for (; nsym; nsym--, sym++) {
2195 if (sym->st_value
2196 && (1<<(sym->st_info&0xf) & OK_TYPES)
2197 && (1<<(sym->st_info>>4) & OK_BINDS)) {
2198 size_t symaddr = (size_t)laddr(p, sym->st_value);
2199 if (symaddr > addr || symaddr <= best)
2200 continue;
2201 best = symaddr;
2202 bestsym = sym;
2203 besterr = addr - symaddr;
2204 if (addr == symaddr)
2205 break;
2206 }
2207 }
2208
2209 if (best && besterr > bestsym->st_size-1) {
2210 best = 0;
2211 bestsym = 0;
2212 }
2213
2214 info->dli_fname = p->name;
2215 info->dli_fbase = p->map;
2216
2217 if (!best) {
2218 info->dli_sname = 0;
2219 info->dli_saddr = 0;
2220 return 1;
2221 }
2222
2223 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2224 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2225 info->dli_sname = strings + bestsym->st_name;
2226 info->dli_saddr = (void *)best;
2227
2228 return 1;
2229 }
2230
2231 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2232 {
2233 void *res;
2234 pthread_rwlock_rdlock(&lock);
2235 res = do_dlsym(p, s, ra);
2236 pthread_rwlock_unlock(&lock);
2237 return res;
2238 }
2239
2240 hidden void *__dlsym_redir_time64(void *restrict p, const char *restrict s, void *restrict ra)
2241 {
2242 #if _REDIR_TIME64
2243 const char *suffix, *suffix2 = "";
2244 char redir[36];
2245
2246 /* Map the symbol name to a time64 version of itself according to the
2247 * pattern used for naming the redirected time64 symbols. */
2248 size_t l = strnlen(s, sizeof redir);
2249 if (l<4 || l==sizeof redir) goto no_redir;
2250 if (s[l-2]=='_' && s[l-1]=='r') {
2251 l -= 2;
2252 suffix2 = s+l;
2253 }
2254 if (l<4) goto no_redir;
2255 if (!strcmp(s+l-4, "time")) suffix = "64";
2256 else suffix = "_time64";
2257
2258 /* Use the presence of the remapped symbol name in libc to determine
2259 * whether it's one that requires time64 redirection; replace if so. */
2260 snprintf(redir, sizeof redir, "__%.*s%s%s", (int)l, s, suffix, suffix2);
2261 if (find_sym(&ldso, redir, 1).sym) s = redir;
2262 no_redir:
2263 #endif
2264 return __dlsym(p, s, ra);
2265 }
2266
2267 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2268 {
2269 struct dso *current;
2270 struct dl_phdr_info info;
2271 int ret = 0;
2272 for(current = head; current;) {
2273 info.dlpi_addr = (uintptr_t)current->base;
2274 info.dlpi_name = current->name;
2275 info.dlpi_phdr = current->phdr;
2276 info.dlpi_phnum = current->phnum;
2277 info.dlpi_adds = gencnt;
2278 info.dlpi_subs = 0;
2279 info.dlpi_tls_modid = current->tls_id;
2280 info.dlpi_tls_data = current->tls.image;
2281
2282 ret = (callback)(&info, sizeof (info), data);
2283
2284 if (ret != 0) break;
2285
2286 pthread_rwlock_rdlock(&lock);
2287 current = current->next;
2288 pthread_rwlock_unlock(&lock);
2289 }
2290 return ret;
2291 }
2292
2293 static void error(const char *fmt, ...)
2294 {
2295 va_list ap;
2296 va_start(ap, fmt);
2297 if (!runtime) {
2298 vdprintf(2, fmt, ap);
2299 dprintf(2, "\n");
2300 ldso_fail = 1;
2301 va_end(ap);
2302 return;
2303 }
2304 __dl_vseterr(fmt, ap);
2305 va_end(ap);
2306 }
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