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deduplicate TP_ADJ logic out of each arch, replace with TP_OFFSET
[musl.git] / ldso / dynlink.c
blobd3d4ddd287fe91a23331bfd47934c9b7924e5c7b
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
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 #define countof(a) ((sizeof (a))/(sizeof (a)[0]))
34
35 struct debug {
36 int ver;
37 void *head;
38 void (*bp)(void);
39 int state;
40 void *base;
41 };
42
43 struct td_index {
44 size_t args[2];
45 struct td_index *next;
46 };
47
48 struct dso {
49 #if DL_FDPIC
50 struct fdpic_loadmap *loadmap;
51 #else
52 unsigned char *base;
53 #endif
54 char *name;
55 size_t *dynv;
56 struct dso *next, *prev;
57
58 Phdr *phdr;
59 int phnum;
60 size_t phentsize;
61 Sym *syms;
62 Elf_Symndx *hashtab;
63 uint32_t *ghashtab;
64 int16_t *versym;
65 char *strings;
66 struct dso *syms_next, *lazy_next;
67 size_t *lazy, lazy_cnt;
68 unsigned char *map;
69 size_t map_len;
70 dev_t dev;
71 ino_t ino;
72 char relocated;
73 char constructed;
74 char kernel_mapped;
75 char mark;
76 char bfs_built;
77 char runtime_loaded;
78 struct dso **deps, *needed_by;
79 size_t ndeps_direct;
80 size_t next_dep;
81 int ctor_visitor;
82 char *rpath_orig, *rpath;
83 struct tls_module tls;
84 size_t tls_id;
85 size_t relro_start, relro_end;
86 uintptr_t *new_dtv;
87 unsigned char *new_tls;
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 typedef void (*stage3_func)(size_t *, size_t *);
110
111 static struct builtin_tls {
112 char c;
113 struct pthread pt;
114 void *space[16];
115 } builtin_tls[1];
116 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
117
118 #define ADDEND_LIMIT 4096
119 static size_t *saved_addends, *apply_addends_to;
120
121 static struct dso ldso;
122 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
123 static char *env_path, *sys_path;
124 static unsigned long long gencnt;
125 static int runtime;
126 static int ldd_mode;
127 static int ldso_fail;
128 static int noload;
129 static int shutting_down;
130 static jmp_buf *rtld_fail;
131 static pthread_rwlock_t lock;
132 static struct debug debug;
133 static struct tls_module *tls_tail;
134 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
135 static size_t static_tls_cnt;
136 static pthread_mutex_t init_fini_lock;
137 static pthread_cond_t ctor_cond;
138 static struct dso *builtin_deps[2];
139 static struct dso *const no_deps[1];
140 static struct dso *builtin_ctor_queue[4];
141 static struct dso **main_ctor_queue;
142 static struct fdpic_loadmap *app_loadmap;
143 static struct fdpic_dummy_loadmap app_dummy_loadmap;
144
145 struct debug *_dl_debug_addr = &debug;
146
147 extern hidden int __malloc_replaced;
148
149 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
150
151 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
152
153 weak_alias(__init_array_start, __init_array_end);
154 weak_alias(__fini_array_start, __fini_array_end);
155
156 static int dl_strcmp(const char *l, const char *r)
157 {
158 for (; *l==*r && *l; l++, r++);
159 return *(unsigned char *)l - *(unsigned char *)r;
160 }
161 #define strcmp(l,r) dl_strcmp(l,r)
162
163 /* Compute load address for a virtual address in a given dso. */
164 #if DL_FDPIC
165 static void *laddr(const struct dso *p, size_t v)
166 {
167 size_t j=0;
168 if (!p->loadmap) return p->base + v;
169 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
170 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
171 }
172 static void *laddr_pg(const struct dso *p, size_t v)
173 {
174 size_t j=0;
175 size_t pgsz = PAGE_SIZE;
176 if (!p->loadmap) return p->base + v;
177 for (j=0; ; j++) {
178 size_t a = p->loadmap->segs[j].p_vaddr;
179 size_t b = a + p->loadmap->segs[j].p_memsz;
180 a &= -pgsz;
181 b += pgsz-1;
182 b &= -pgsz;
183 if (v-a<b-a) break;
184 }
185 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
186 }
187 static void (*fdbarrier(void *p))()
188 {
189 void (*fd)();
190 __asm__("" : "=r"(fd) : "0"(p));
191 return fd;
192 }
193 #define fpaddr(p, v) fdbarrier((&(struct funcdesc){ \
194 laddr(p, v), (p)->got }))
195 #else
196 #define laddr(p, v) (void *)((p)->base + (v))
197 #define laddr_pg(p, v) laddr(p, v)
198 #define fpaddr(p, v) ((void (*)())laddr(p, v))
199 #endif
200
201 static void decode_vec(size_t *v, size_t *a, size_t cnt)
202 {
203 size_t i;
204 for (i=0; i<cnt; i++) a[i] = 0;
205 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
206 a[0] |= 1UL<<v[0];
207 a[v[0]] = v[1];
208 }
209 }
210
211 static int search_vec(size_t *v, size_t *r, size_t key)
212 {
213 for (; v[0]!=key; v+=2)
214 if (!v[0]) return 0;
215 *r = v[1];
216 return 1;
217 }
218
219 static uint32_t sysv_hash(const char *s0)
220 {
221 const unsigned char *s = (void *)s0;
222 uint_fast32_t h = 0;
223 while (*s) {
224 h = 16*h + *s++;
225 h ^= h>>24 & 0xf0;
226 }
227 return h & 0xfffffff;
228 }
229
230 static uint32_t gnu_hash(const char *s0)
231 {
232 const unsigned char *s = (void *)s0;
233 uint_fast32_t h = 5381;
234 for (; *s; s++)
235 h += h*32 + *s;
236 return h;
237 }
238
239 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
240 {
241 size_t i;
242 Sym *syms = dso->syms;
243 Elf_Symndx *hashtab = dso->hashtab;
244 char *strings = dso->strings;
245 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
246 if ((!dso->versym || dso->versym[i] >= 0)
247 && (!strcmp(s, strings+syms[i].st_name)))
248 return syms+i;
249 }
250 return 0;
251 }
252
253 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
254 {
255 uint32_t nbuckets = hashtab[0];
256 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
257 uint32_t i = buckets[h1 % nbuckets];
258
259 if (!i) return 0;
260
261 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
262
263 for (h1 |= 1; ; i++) {
264 uint32_t h2 = *hashval++;
265 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
266 && !strcmp(s, dso->strings + dso->syms[i].st_name))
267 return dso->syms+i;
268 if (h2 & 1) break;
269 }
270
271 return 0;
272 }
273
274 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
275 {
276 const size_t *bloomwords = (const void *)(hashtab+4);
277 size_t f = bloomwords[fofs & (hashtab[2]-1)];
278 if (!(f & fmask)) return 0;
279
280 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
281 if (!(f & 1)) return 0;
282
283 return gnu_lookup(h1, hashtab, dso, s);
284 }
285
286 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
287 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
288
289 #ifndef ARCH_SYM_REJECT_UND
290 #define ARCH_SYM_REJECT_UND(s) 0
291 #endif
292
293 #if defined(__GNUC__)
294 __attribute__((always_inline))
295 #endif
296 static inline struct symdef find_sym2(struct dso *dso, const char *s, int need_def, int use_deps)
297 {
298 uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
299 size_t ghm = 1ul << gh % (8*sizeof(size_t));
300 struct symdef def = {0};
301 struct dso **deps = use_deps ? dso->deps : 0;
302 for (; dso; dso=use_deps ? *deps++ : dso->syms_next) {
303 Sym *sym;
304 if ((ght = dso->ghashtab)) {
305 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
306 } else {
307 if (!h) h = sysv_hash(s);
308 sym = sysv_lookup(s, h, dso);
309 }
310 if (!sym) continue;
311 if (!sym->st_shndx)
312 if (need_def || (sym->st_info&0xf) == STT_TLS
313 || ARCH_SYM_REJECT_UND(sym))
314 continue;
315 if (!sym->st_value)
316 if ((sym->st_info&0xf) != STT_TLS)
317 continue;
318 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
319 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
320 def.sym = sym;
321 def.dso = dso;
322 break;
323 }
324 return def;
325 }
326
327 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
328 {
329 return find_sym2(dso, s, need_def, 0);
330 }
331
332 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
333 {
334 unsigned char *base = dso->base;
335 Sym *syms = dso->syms;
336 char *strings = dso->strings;
337 Sym *sym;
338 const char *name;
339 void *ctx;
340 int type;
341 int sym_index;
342 struct symdef def;
343 size_t *reloc_addr;
344 size_t sym_val;
345 size_t tls_val;
346 size_t addend;
347 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
348
349 if (dso == &ldso) {
350 /* Only ldso's REL table needs addend saving/reuse. */
351 if (rel == apply_addends_to)
352 reuse_addends = 1;
353 skip_relative = 1;
354 }
355
356 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
357 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
358 type = R_TYPE(rel[1]);
359 if (type == REL_NONE) continue;
360 reloc_addr = laddr(dso, rel[0]);
361
362 if (stride > 2) {
363 addend = rel[2];
364 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
365 addend = 0;
366 } else if (reuse_addends) {
367 /* Save original addend in stage 2 where the dso
368 * chain consists of just ldso; otherwise read back
369 * saved addend since the inline one was clobbered. */
370 if (head==&ldso)
371 saved_addends[save_slot] = *reloc_addr;
372 addend = saved_addends[save_slot++];
373 } else {
374 addend = *reloc_addr;
375 }
376
377 sym_index = R_SYM(rel[1]);
378 if (sym_index) {
379 sym = syms + sym_index;
380 name = strings + sym->st_name;
381 ctx = type==REL_COPY ? head->syms_next : head;
382 def = (sym->st_info>>4) == STB_LOCAL
383 ? (struct symdef){ .dso = dso, .sym = sym }
384 : find_sym(ctx, name, type==REL_PLT);
385 if (!def.sym && (sym->st_shndx != SHN_UNDEF
386 || sym->st_info>>4 != STB_WEAK)) {
387 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
388 dso->lazy[3*dso->lazy_cnt+0] = rel[0];
389 dso->lazy[3*dso->lazy_cnt+1] = rel[1];
390 dso->lazy[3*dso->lazy_cnt+2] = addend;
391 dso->lazy_cnt++;
392 continue;
393 }
394 error("Error relocating %s: %s: symbol not found",
395 dso->name, name);
396 if (runtime) longjmp(*rtld_fail, 1);
397 continue;
398 }
399 } else {
400 sym = 0;
401 def.sym = 0;
402 def.dso = dso;
403 }
404
405 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
406 tls_val = def.sym ? def.sym->st_value : 0;
407
408 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
409 && def.dso->tls_id > static_tls_cnt) {
410 error("Error relocating %s: %s: initial-exec TLS "
411 "resolves to dynamic definition in %s",
412 dso->name, name, def.dso->name);
413 longjmp(*rtld_fail, 1);
414 }
415
416 switch(type) {
417 case REL_OFFSET:
418 addend -= (size_t)reloc_addr;
419 case REL_SYMBOLIC:
420 case REL_GOT:
421 case REL_PLT:
422 *reloc_addr = sym_val + addend;
423 break;
424 case REL_USYMBOLIC:
425 memcpy(reloc_addr, &(size_t){sym_val + addend}, sizeof(size_t));
426 break;
427 case REL_RELATIVE:
428 *reloc_addr = (size_t)base + addend;
429 break;
430 case REL_SYM_OR_REL:
431 if (sym) *reloc_addr = sym_val + addend;
432 else *reloc_addr = (size_t)base + addend;
433 break;
434 case REL_COPY:
435 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
436 break;
437 case REL_OFFSET32:
438 *(uint32_t *)reloc_addr = sym_val + addend
439 - (size_t)reloc_addr;
440 break;
441 case REL_FUNCDESC:
442 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
443 + (def.sym - def.dso->syms)) : 0;
444 break;
445 case REL_FUNCDESC_VAL:
446 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
447 else *reloc_addr = sym_val;
448 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
449 break;
450 case REL_DTPMOD:
451 *reloc_addr = def.dso->tls_id;
452 break;
453 case REL_DTPOFF:
454 *reloc_addr = tls_val + addend - DTP_OFFSET;
455 break;
456 #ifdef TLS_ABOVE_TP
457 case REL_TPOFF:
458 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
459 break;
460 #else
461 case REL_TPOFF:
462 *reloc_addr = tls_val - def.dso->tls.offset + addend;
463 break;
464 case REL_TPOFF_NEG:
465 *reloc_addr = def.dso->tls.offset - tls_val + addend;
466 break;
467 #endif
468 case REL_TLSDESC:
469 if (stride<3) addend = reloc_addr[1];
470 if (def.dso->tls_id > static_tls_cnt) {
471 struct td_index *new = malloc(sizeof *new);
472 if (!new) {
473 error(
474 "Error relocating %s: cannot allocate TLSDESC for %s",
475 dso->name, sym ? name : "(local)" );
476 longjmp(*rtld_fail, 1);
477 }
478 new->next = dso->td_index;
479 dso->td_index = new;
480 new->args[0] = def.dso->tls_id;
481 new->args[1] = tls_val + addend - DTP_OFFSET;
482 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
483 reloc_addr[1] = (size_t)new;
484 } else {
485 reloc_addr[0] = (size_t)__tlsdesc_static;
486 #ifdef TLS_ABOVE_TP
487 reloc_addr[1] = tls_val + def.dso->tls.offset
488 + TPOFF_K + addend;
489 #else
490 reloc_addr[1] = tls_val - def.dso->tls.offset
491 + addend;
492 #endif
493 }
494 #ifdef TLSDESC_BACKWARDS
495 /* Some archs (32-bit ARM at least) invert the order of
496 * the descriptor members. Fix them up here. */
497 size_t tmp = reloc_addr[0];
498 reloc_addr[0] = reloc_addr[1];
499 reloc_addr[1] = tmp;
500 #endif
501 break;
502 default:
503 error("Error relocating %s: unsupported relocation type %d",
504 dso->name, type);
505 if (runtime) longjmp(*rtld_fail, 1);
506 continue;
507 }
508 }
509 }
510
511 static void redo_lazy_relocs()
512 {
513 struct dso *p = lazy_head, *next;
514 lazy_head = 0;
515 for (; p; p=next) {
516 next = p->lazy_next;
517 size_t size = p->lazy_cnt*3*sizeof(size_t);
518 p->lazy_cnt = 0;
519 do_relocs(p, p->lazy, size, 3);
520 if (p->lazy_cnt) {
521 p->lazy_next = lazy_head;
522 lazy_head = p;
523 } else {
524 free(p->lazy);
525 p->lazy = 0;
526 p->lazy_next = 0;
527 }
528 }
529 }
530
531 /* A huge hack: to make up for the wastefulness of shared libraries
532 * needing at least a page of dirty memory even if they have no global
533 * data, we reclaim the gaps at the beginning and end of writable maps
534 * and "donate" them to the heap. */
535
536 static void reclaim(struct dso *dso, size_t start, size_t end)
537 {
538 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
539 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
540 if (start >= end) return;
541 char *base = laddr_pg(dso, start);
542 __malloc_donate(base, base+(end-start));
543 }
544
545 static void reclaim_gaps(struct dso *dso)
546 {
547 Phdr *ph = dso->phdr;
548 size_t phcnt = dso->phnum;
549
550 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
551 if (ph->p_type!=PT_LOAD) continue;
552 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
553 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
554 reclaim(dso, ph->p_vaddr+ph->p_memsz,
555 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
556 }
557 }
558
559 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
560 {
561 static int no_map_fixed;
562 char *q;
563 if (!no_map_fixed) {
564 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
565 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
566 return q;
567 no_map_fixed = 1;
568 }
569 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
570 if (flags & MAP_ANONYMOUS) {
571 memset(p, 0, n);
572 return p;
573 }
574 ssize_t r;
575 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
576 for (q=p; n; q+=r, off+=r, n-=r) {
577 r = read(fd, q, n);
578 if (r < 0 && errno != EINTR) return MAP_FAILED;
579 if (!r) {
580 memset(q, 0, n);
581 break;
582 }
583 }
584 return p;
585 }
586
587 static void unmap_library(struct dso *dso)
588 {
589 if (dso->loadmap) {
590 size_t i;
591 for (i=0; i<dso->loadmap->nsegs; i++) {
592 if (!dso->loadmap->segs[i].p_memsz)
593 continue;
594 munmap((void *)dso->loadmap->segs[i].addr,
595 dso->loadmap->segs[i].p_memsz);
596 }
597 free(dso->loadmap);
598 } else if (dso->map && dso->map_len) {
599 munmap(dso->map, dso->map_len);
600 }
601 }
602
603 static void *map_library(int fd, struct dso *dso)
604 {
605 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
606 void *allocated_buf=0;
607 size_t phsize;
608 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
609 size_t this_min, this_max;
610 size_t nsegs = 0;
611 off_t off_start;
612 Ehdr *eh;
613 Phdr *ph, *ph0;
614 unsigned prot;
615 unsigned char *map=MAP_FAILED, *base;
616 size_t dyn=0;
617 size_t tls_image=0;
618 size_t i;
619
620 ssize_t l = read(fd, buf, sizeof buf);
621 eh = buf;
622 if (l<0) return 0;
623 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
624 goto noexec;
625 phsize = eh->e_phentsize * eh->e_phnum;
626 if (phsize > sizeof buf - sizeof *eh) {
627 allocated_buf = malloc(phsize);
628 if (!allocated_buf) return 0;
629 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
630 if (l < 0) goto error;
631 if (l != phsize) goto noexec;
632 ph = ph0 = allocated_buf;
633 } else if (eh->e_phoff + phsize > l) {
634 l = pread(fd, buf+1, phsize, eh->e_phoff);
635 if (l < 0) goto error;
636 if (l != phsize) goto noexec;
637 ph = ph0 = (void *)(buf + 1);
638 } else {
639 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
640 }
641 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
642 if (ph->p_type == PT_DYNAMIC) {
643 dyn = ph->p_vaddr;
644 } else if (ph->p_type == PT_TLS) {
645 tls_image = ph->p_vaddr;
646 dso->tls.align = ph->p_align;
647 dso->tls.len = ph->p_filesz;
648 dso->tls.size = ph->p_memsz;
649 } else if (ph->p_type == PT_GNU_RELRO) {
650 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
651 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
652 } else if (ph->p_type == PT_GNU_STACK) {
653 if (!runtime && ph->p_memsz > __default_stacksize) {
654 __default_stacksize =
655 ph->p_memsz < DEFAULT_STACK_MAX ?
656 ph->p_memsz : DEFAULT_STACK_MAX;
657 }
658 }
659 if (ph->p_type != PT_LOAD) continue;
660 nsegs++;
661 if (ph->p_vaddr < addr_min) {
662 addr_min = ph->p_vaddr;
663 off_start = ph->p_offset;
664 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
665 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
666 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
667 }
668 if (ph->p_vaddr+ph->p_memsz > addr_max) {
669 addr_max = ph->p_vaddr+ph->p_memsz;
670 }
671 }
672 if (!dyn) goto noexec;
673 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
674 dso->loadmap = calloc(1, sizeof *dso->loadmap
675 + nsegs * sizeof *dso->loadmap->segs);
676 if (!dso->loadmap) goto error;
677 dso->loadmap->nsegs = nsegs;
678 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
679 if (ph->p_type != PT_LOAD) continue;
680 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
681 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
682 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
683 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
684 prot, MAP_PRIVATE,
685 fd, ph->p_offset & -PAGE_SIZE);
686 if (map == MAP_FAILED) {
687 unmap_library(dso);
688 goto error;
689 }
690 dso->loadmap->segs[i].addr = (size_t)map +
691 (ph->p_vaddr & PAGE_SIZE-1);
692 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
693 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
694 i++;
695 if (prot & PROT_WRITE) {
696 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
697 + ph->p_filesz;
698 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
699 size_t pgend = brk + ph->p_memsz - ph->p_filesz
700 + PAGE_SIZE-1 & -PAGE_SIZE;
701 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
702 pgend-pgbrk, prot,
703 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
704 -1, off_start) == MAP_FAILED)
705 goto error;
706 memset(map + brk, 0, pgbrk-brk);
707 }
708 }
709 map = (void *)dso->loadmap->segs[0].addr;
710 map_len = 0;
711 goto done_mapping;
712 }
713 addr_max += PAGE_SIZE-1;
714 addr_max &= -PAGE_SIZE;
715 addr_min &= -PAGE_SIZE;
716 off_start &= -PAGE_SIZE;
717 map_len = addr_max - addr_min + off_start;
718 /* The first time, we map too much, possibly even more than
719 * the length of the file. This is okay because we will not
720 * use the invalid part; we just need to reserve the right
721 * amount of virtual address space to map over later. */
722 map = DL_NOMMU_SUPPORT
723 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
724 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
725 : mmap((void *)addr_min, map_len, prot,
726 MAP_PRIVATE, fd, off_start);
727 if (map==MAP_FAILED) goto error;
728 dso->map = map;
729 dso->map_len = map_len;
730 /* If the loaded file is not relocatable and the requested address is
731 * not available, then the load operation must fail. */
732 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
733 errno = EBUSY;
734 goto error;
735 }
736 base = map - addr_min;
737 dso->phdr = 0;
738 dso->phnum = 0;
739 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
740 if (ph->p_type != PT_LOAD) continue;
741 /* Check if the programs headers are in this load segment, and
742 * if so, record the address for use by dl_iterate_phdr. */
743 if (!dso->phdr && eh->e_phoff >= ph->p_offset
744 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
745 dso->phdr = (void *)(base + ph->p_vaddr
746 + (eh->e_phoff-ph->p_offset));
747 dso->phnum = eh->e_phnum;
748 dso->phentsize = eh->e_phentsize;
749 }
750 this_min = ph->p_vaddr & -PAGE_SIZE;
751 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
752 off_start = ph->p_offset & -PAGE_SIZE;
753 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
754 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
755 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
756 /* Reuse the existing mapping for the lowest-address LOAD */
757 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
758 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
759 goto error;
760 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
761 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
762 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
763 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
764 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)
765 goto error;
766 }
767 }
768 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
769 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
770 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
771 && errno != ENOSYS)
772 goto error;
773 break;
774 }
775 done_mapping:
776 dso->base = base;
777 dso->dynv = laddr(dso, dyn);
778 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
779 free(allocated_buf);
780 return map;
781 noexec:
782 errno = ENOEXEC;
783 error:
784 if (map!=MAP_FAILED) unmap_library(dso);
785 free(allocated_buf);
786 return 0;
787 }
788
789 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
790 {
791 size_t l;
792 int fd;
793 for (;;) {
794 s += strspn(s, ":\n");
795 l = strcspn(s, ":\n");
796 if (l-1 >= INT_MAX) return -1;
797 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
798 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
799 switch (errno) {
800 case ENOENT:
801 case ENOTDIR:
802 case EACCES:
803 case ENAMETOOLONG:
804 break;
805 default:
806 /* Any negative value but -1 will inhibit
807 * futher path search. */
808 return -2;
809 }
810 }
811 s += l;
812 }
813 }
814
815 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
816 {
817 size_t n, l;
818 const char *s, *t, *origin;
819 char *d;
820 if (p->rpath || !p->rpath_orig) return 0;
821 if (!strchr(p->rpath_orig, '$')) {
822 p->rpath = p->rpath_orig;
823 return 0;
824 }
825 n = 0;
826 s = p->rpath_orig;
827 while ((t=strchr(s, '$'))) {
828 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
829 return 0;
830 s = t+1;
831 n++;
832 }
833 if (n > SSIZE_MAX/PATH_MAX) return 0;
834
835 if (p->kernel_mapped) {
836 /* $ORIGIN searches cannot be performed for the main program
837 * when it is suid/sgid/AT_SECURE. This is because the
838 * pathname is under the control of the caller of execve.
839 * For libraries, however, $ORIGIN can be processed safely
840 * since the library's pathname came from a trusted source
841 * (either system paths or a call to dlopen). */
842 if (libc.secure)
843 return 0;
844 l = readlink("/proc/self/exe", buf, buf_size);
845 if (l == -1) switch (errno) {
846 case ENOENT:
847 case ENOTDIR:
848 case EACCES:
849 break;
850 default:
851 return -1;
852 }
853 if (l >= buf_size)
854 return 0;
855 buf[l] = 0;
856 origin = buf;
857 } else {
858 origin = p->name;
859 }
860 t = strrchr(origin, '/');
861 if (t) {
862 l = t-origin;
863 } else {
864 /* Normally p->name will always be an absolute or relative
865 * pathname containing at least one '/' character, but in the
866 * case where ldso was invoked as a command to execute a
867 * program in the working directory, app.name may not. Fix. */
868 origin = ".";
869 l = 1;
870 }
871 /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
872 if (libc.secure && *origin != '/')
873 return 0;
874 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
875 if (!p->rpath) return -1;
876
877 d = p->rpath;
878 s = p->rpath_orig;
879 while ((t=strchr(s, '$'))) {
880 memcpy(d, s, t-s);
881 d += t-s;
882 memcpy(d, origin, l);
883 d += l;
884 /* It was determined previously that the '$' is followed
885 * either by "ORIGIN" or "{ORIGIN}". */
886 s = t + 7 + 2*(t[1]=='{');
887 }
888 strcpy(d, s);
889 return 0;
890 }
891
892 static void decode_dyn(struct dso *p)
893 {
894 size_t dyn[DYN_CNT];
895 decode_vec(p->dynv, dyn, DYN_CNT);
896 p->syms = laddr(p, dyn[DT_SYMTAB]);
897 p->strings = laddr(p, dyn[DT_STRTAB]);
898 if (dyn[0]&(1<<DT_HASH))
899 p->hashtab = laddr(p, dyn[DT_HASH]);
900 if (dyn[0]&(1<<DT_RPATH))
901 p->rpath_orig = p->strings + dyn[DT_RPATH];
902 if (dyn[0]&(1<<DT_RUNPATH))
903 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
904 if (dyn[0]&(1<<DT_PLTGOT))
905 p->got = laddr(p, dyn[DT_PLTGOT]);
906 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
907 p->ghashtab = laddr(p, *dyn);
908 if (search_vec(p->dynv, dyn, DT_VERSYM))
909 p->versym = laddr(p, *dyn);
910 }
911
912 static size_t count_syms(struct dso *p)
913 {
914 if (p->hashtab) return p->hashtab[1];
915
916 size_t nsym, i;
917 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
918 uint32_t *hashval;
919 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
920 if (buckets[i] > nsym)
921 nsym = buckets[i];
922 }
923 if (nsym) {
924 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
925 do nsym++;
926 while (!(*hashval++ & 1));
927 }
928 return nsym;
929 }
930
931 static void *dl_mmap(size_t n)
932 {
933 void *p;
934 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
935 #ifdef SYS_mmap2
936 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
937 #else
938 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
939 #endif
940 return (unsigned long)p > -4096UL ? 0 : p;
941 }
942
943 static void makefuncdescs(struct dso *p)
944 {
945 static int self_done;
946 size_t nsym = count_syms(p);
947 size_t i, size = nsym * sizeof(*p->funcdescs);
948
949 if (!self_done) {
950 p->funcdescs = dl_mmap(size);
951 self_done = 1;
952 } else {
953 p->funcdescs = malloc(size);
954 }
955 if (!p->funcdescs) {
956 if (!runtime) a_crash();
957 error("Error allocating function descriptors for %s", p->name);
958 longjmp(*rtld_fail, 1);
959 }
960 for (i=0; i<nsym; i++) {
961 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
962 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
963 p->funcdescs[i].got = p->got;
964 } else {
965 p->funcdescs[i].addr = 0;
966 p->funcdescs[i].got = 0;
967 }
968 }
969 }
970
971 static struct dso *load_library(const char *name, struct dso *needed_by)
972 {
973 char buf[2*NAME_MAX+2];
974 const char *pathname;
975 unsigned char *map;
976 struct dso *p, temp_dso = {0};
977 int fd;
978 struct stat st;
979 size_t alloc_size;
980 int n_th = 0;
981 int is_self = 0;
982
983 if (!*name) {
984 errno = EINVAL;
985 return 0;
986 }
987
988 /* Catch and block attempts to reload the implementation itself */
989 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
990 static const char reserved[] =
991 "c.pthread.rt.m.dl.util.xnet.";
992 const char *rp, *next;
993 for (rp=reserved; *rp; rp=next) {
994 next = strchr(rp, '.') + 1;
995 if (strncmp(name+3, rp, next-rp) == 0)
996 break;
997 }
998 if (*rp) {
999 if (ldd_mode) {
1000 /* Track which names have been resolved
1001 * and only report each one once. */
1002 static unsigned reported;
1003 unsigned mask = 1U<<(rp-reserved);
1004 if (!(reported & mask)) {
1005 reported |= mask;
1006 dprintf(1, "\t%s => %s (%p)\n",
1007 name, ldso.name,
1008 ldso.base);
1009 }
1010 }
1011 is_self = 1;
1012 }
1013 }
1014 if (!strcmp(name, ldso.name)) is_self = 1;
1015 if (is_self) {
1016 if (!ldso.prev) {
1017 tail->next = &ldso;
1018 ldso.prev = tail;
1019 tail = &ldso;
1020 }
1021 return &ldso;
1022 }
1023 if (strchr(name, '/')) {
1024 pathname = name;
1025 fd = open(name, O_RDONLY|O_CLOEXEC);
1026 } else {
1027 /* Search for the name to see if it's already loaded */
1028 for (p=head->next; p; p=p->next) {
1029 if (p->shortname && !strcmp(p->shortname, name)) {
1030 return p;
1031 }
1032 }
1033 if (strlen(name) > NAME_MAX) return 0;
1034 fd = -1;
1035 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
1036 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
1037 if (fixup_rpath(p, buf, sizeof buf) < 0)
1038 fd = -2; /* Inhibit further search. */
1039 if (p->rpath)
1040 fd = path_open(name, p->rpath, buf, sizeof buf);
1041 }
1042 if (fd == -1) {
1043 if (!sys_path) {
1044 char *prefix = 0;
1045 size_t prefix_len;
1046 if (ldso.name[0]=='/') {
1047 char *s, *t, *z;
1048 for (s=t=z=ldso.name; *s; s++)
1049 if (*s=='/') z=t, t=s;
1050 prefix_len = z-ldso.name;
1051 if (prefix_len < PATH_MAX)
1052 prefix = ldso.name;
1053 }
1054 if (!prefix) {
1055 prefix = "";
1056 prefix_len = 0;
1057 }
1058 char etc_ldso_path[prefix_len + 1
1059 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1060 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1061 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1062 (int)prefix_len, prefix);
1063 FILE *f = fopen(etc_ldso_path, "rbe");
1064 if (f) {
1065 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1066 free(sys_path);
1067 sys_path = "";
1068 }
1069 fclose(f);
1070 } else if (errno != ENOENT) {
1071 sys_path = "";
1072 }
1073 }
1074 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1075 fd = path_open(name, sys_path, buf, sizeof buf);
1076 }
1077 pathname = buf;
1078 }
1079 if (fd < 0) return 0;
1080 if (fstat(fd, &st) < 0) {
1081 close(fd);
1082 return 0;
1083 }
1084 for (p=head->next; p; p=p->next) {
1085 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1086 /* If this library was previously loaded with a
1087 * pathname but a search found the same inode,
1088 * setup its shortname so it can be found by name. */
1089 if (!p->shortname && pathname != name)
1090 p->shortname = strrchr(p->name, '/')+1;
1091 close(fd);
1092 return p;
1093 }
1094 }
1095 map = noload ? 0 : map_library(fd, &temp_dso);
1096 close(fd);
1097 if (!map) return 0;
1098
1099 /* Avoid the danger of getting two versions of libc mapped into the
1100 * same process when an absolute pathname was used. The symbols
1101 * checked are chosen to catch both musl and glibc, and to avoid
1102 * false positives from interposition-hack libraries. */
1103 decode_dyn(&temp_dso);
1104 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1105 find_sym(&temp_dso, "stdin", 1).sym) {
1106 unmap_library(&temp_dso);
1107 return load_library("libc.so", needed_by);
1108 }
1109 /* Past this point, if we haven't reached runtime yet, ldso has
1110 * committed either to use the mapped library or to abort execution.
1111 * Unmapping is not possible, so we can safely reclaim gaps. */
1112 if (!runtime) reclaim_gaps(&temp_dso);
1113
1114 /* Allocate storage for the new DSO. When there is TLS, this
1115 * storage must include a reservation for all pre-existing
1116 * threads to obtain copies of both the new TLS, and an
1117 * extended DTV capable of storing an additional slot for
1118 * the newly-loaded DSO. */
1119 alloc_size = sizeof *p + strlen(pathname) + 1;
1120 if (runtime && temp_dso.tls.image) {
1121 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1122 + sizeof(void *) * (tls_cnt+3);
1123 n_th = libc.threads_minus_1 + 1;
1124 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1125 else alloc_size += n_th * per_th;
1126 }
1127 p = calloc(1, alloc_size);
1128 if (!p) {
1129 unmap_library(&temp_dso);
1130 return 0;
1131 }
1132 memcpy(p, &temp_dso, sizeof temp_dso);
1133 p->dev = st.st_dev;
1134 p->ino = st.st_ino;
1135 p->needed_by = needed_by;
1136 p->name = p->buf;
1137 p->runtime_loaded = runtime;
1138 strcpy(p->name, pathname);
1139 /* Add a shortname only if name arg was not an explicit pathname. */
1140 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1141 if (p->tls.image) {
1142 p->tls_id = ++tls_cnt;
1143 tls_align = MAXP2(tls_align, p->tls.align);
1144 #ifdef TLS_ABOVE_TP
1145 p->tls.offset = tls_offset + ( (p->tls.align-1) &
1146 (-tls_offset + (uintptr_t)p->tls.image) );
1147 tls_offset = p->tls.offset + p->tls.size;
1148 #else
1149 tls_offset += p->tls.size + p->tls.align - 1;
1150 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1151 & (p->tls.align-1);
1152 p->tls.offset = tls_offset;
1153 #endif
1154 p->new_dtv = (void *)(-sizeof(size_t) &
1155 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1156 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1157 if (tls_tail) tls_tail->next = &p->tls;
1158 else libc.tls_head = &p->tls;
1159 tls_tail = &p->tls;
1160 }
1161
1162 tail->next = p;
1163 p->prev = tail;
1164 tail = p;
1165
1166 if (DL_FDPIC) makefuncdescs(p);
1167
1168 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1169
1170 return p;
1171 }
1172
1173 static void load_direct_deps(struct dso *p)
1174 {
1175 size_t i, cnt=0;
1176
1177 if (p->deps) return;
1178 /* For head, all preloads are direct pseudo-dependencies.
1179 * Count and include them now to avoid realloc later. */
1180 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1181 cnt++;
1182 for (i=0; p->dynv[i]; i+=2)
1183 if (p->dynv[i] == DT_NEEDED) cnt++;
1184 /* Use builtin buffer for apps with no external deps, to
1185 * preserve property of no runtime failure paths. */
1186 p->deps = (p==head && cnt<2) ? builtin_deps :
1187 calloc(cnt+1, sizeof *p->deps);
1188 if (!p->deps) {
1189 error("Error loading dependencies for %s", p->name);
1190 if (runtime) longjmp(*rtld_fail, 1);
1191 }
1192 cnt=0;
1193 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1194 p->deps[cnt++] = q;
1195 for (i=0; p->dynv[i]; i+=2) {
1196 if (p->dynv[i] != DT_NEEDED) continue;
1197 struct dso *dep = load_library(p->strings + p->dynv[i+1], p);
1198 if (!dep) {
1199 error("Error loading shared library %s: %m (needed by %s)",
1200 p->strings + p->dynv[i+1], p->name);
1201 if (runtime) longjmp(*rtld_fail, 1);
1202 continue;
1203 }
1204 p->deps[cnt++] = dep;
1205 }
1206 p->deps[cnt] = 0;
1207 p->ndeps_direct = cnt;
1208 }
1209
1210 static void load_deps(struct dso *p)
1211 {
1212 if (p->deps) return;
1213 for (; p; p=p->next)
1214 load_direct_deps(p);
1215 }
1216
1217 static void extend_bfs_deps(struct dso *p)
1218 {
1219 size_t i, j, cnt, ndeps_all;
1220 struct dso **tmp;
1221
1222 /* Can't use realloc if the original p->deps was allocated at
1223 * program entry and malloc has been replaced, or if it's
1224 * the builtin non-allocated trivial main program deps array. */
1225 int no_realloc = (__malloc_replaced && !p->runtime_loaded)
1226 || p->deps == builtin_deps;
1227
1228 if (p->bfs_built) return;
1229 ndeps_all = p->ndeps_direct;
1230
1231 /* Mark existing (direct) deps so they won't be duplicated. */
1232 for (i=0; p->deps[i]; i++)
1233 p->deps[i]->mark = 1;
1234
1235 /* For each dependency already in the list, copy its list of direct
1236 * dependencies to the list, excluding any items already in the
1237 * list. Note that the list this loop iterates over will grow during
1238 * the loop, but since duplicates are excluded, growth is bounded. */
1239 for (i=0; p->deps[i]; i++) {
1240 struct dso *dep = p->deps[i];
1241 for (j=cnt=0; j<dep->ndeps_direct; j++)
1242 if (!dep->deps[j]->mark) cnt++;
1243 tmp = no_realloc ?
1244 malloc(sizeof(*tmp) * (ndeps_all+cnt+1)) :
1245 realloc(p->deps, sizeof(*tmp) * (ndeps_all+cnt+1));
1246 if (!tmp) {
1247 error("Error recording dependencies for %s", p->name);
1248 if (runtime) longjmp(*rtld_fail, 1);
1249 continue;
1250 }
1251 if (no_realloc) {
1252 memcpy(tmp, p->deps, sizeof(*tmp) * (ndeps_all+1));
1253 no_realloc = 0;
1254 }
1255 p->deps = tmp;
1256 for (j=0; j<dep->ndeps_direct; j++) {
1257 if (dep->deps[j]->mark) continue;
1258 dep->deps[j]->mark = 1;
1259 p->deps[ndeps_all++] = dep->deps[j];
1260 }
1261 p->deps[ndeps_all] = 0;
1262 }
1263 p->bfs_built = 1;
1264 for (p=head; p; p=p->next)
1265 p->mark = 0;
1266 }
1267
1268 static void load_preload(char *s)
1269 {
1270 int tmp;
1271 char *z;
1272 for (z=s; *z; s=z) {
1273 for ( ; *s && (isspace(*s) || *s==':'); s++);
1274 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1275 tmp = *z;
1276 *z = 0;
1277 load_library(s, 0);
1278 *z = tmp;
1279 }
1280 }
1281
1282 static void add_syms(struct dso *p)
1283 {
1284 if (!p->syms_next && syms_tail != p) {
1285 syms_tail->syms_next = p;
1286 syms_tail = p;
1287 }
1288 }
1289
1290 static void revert_syms(struct dso *old_tail)
1291 {
1292 struct dso *p, *next;
1293 /* Chop off the tail of the list of dsos that participate in
1294 * the global symbol table, reverting them to RTLD_LOCAL. */
1295 for (p=old_tail; p; p=next) {
1296 next = p->syms_next;
1297 p->syms_next = 0;
1298 }
1299 syms_tail = old_tail;
1300 }
1301
1302 static void do_mips_relocs(struct dso *p, size_t *got)
1303 {
1304 size_t i, j, rel[2];
1305 unsigned char *base = p->base;
1306 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1307 if (p==&ldso) {
1308 got += i;
1309 } else {
1310 while (i--) *got++ += (size_t)base;
1311 }
1312 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1313 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1314 Sym *sym = p->syms + j;
1315 rel[0] = (unsigned char *)got - base;
1316 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1317 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1318 do_relocs(p, rel, sizeof rel, 2);
1319 }
1320 }
1321
1322 static void reloc_all(struct dso *p)
1323 {
1324 size_t dyn[DYN_CNT];
1325 for (; p; p=p->next) {
1326 if (p->relocated) continue;
1327 decode_vec(p->dynv, dyn, DYN_CNT);
1328 if (NEED_MIPS_GOT_RELOCS)
1329 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1330 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1331 2+(dyn[DT_PLTREL]==DT_RELA));
1332 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1333 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1334
1335 if (head != &ldso && p->relro_start != p->relro_end &&
1336 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1337 && errno != ENOSYS) {
1338 error("Error relocating %s: RELRO protection failed: %m",
1339 p->name);
1340 if (runtime) longjmp(*rtld_fail, 1);
1341 }
1342
1343 p->relocated = 1;
1344 }
1345 }
1346
1347 static void kernel_mapped_dso(struct dso *p)
1348 {
1349 size_t min_addr = -1, max_addr = 0, cnt;
1350 Phdr *ph = p->phdr;
1351 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1352 if (ph->p_type == PT_DYNAMIC) {
1353 p->dynv = laddr(p, ph->p_vaddr);
1354 } else if (ph->p_type == PT_GNU_RELRO) {
1355 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1356 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1357 } else if (ph->p_type == PT_GNU_STACK) {
1358 if (!runtime && ph->p_memsz > __default_stacksize) {
1359 __default_stacksize =
1360 ph->p_memsz < DEFAULT_STACK_MAX ?
1361 ph->p_memsz : DEFAULT_STACK_MAX;
1362 }
1363 }
1364 if (ph->p_type != PT_LOAD) continue;
1365 if (ph->p_vaddr < min_addr)
1366 min_addr = ph->p_vaddr;
1367 if (ph->p_vaddr+ph->p_memsz > max_addr)
1368 max_addr = ph->p_vaddr+ph->p_memsz;
1369 }
1370 min_addr &= -PAGE_SIZE;
1371 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1372 p->map = p->base + min_addr;
1373 p->map_len = max_addr - min_addr;
1374 p->kernel_mapped = 1;
1375 }
1376
1377 void __libc_exit_fini()
1378 {
1379 struct dso *p;
1380 size_t dyn[DYN_CNT];
1381 int self = __pthread_self()->tid;
1382
1383 /* Take both locks before setting shutting_down, so that
1384 * either lock is sufficient to read its value. The lock
1385 * order matches that in dlopen to avoid deadlock. */
1386 pthread_rwlock_wrlock(&lock);
1387 pthread_mutex_lock(&init_fini_lock);
1388 shutting_down = 1;
1389 pthread_rwlock_unlock(&lock);
1390 for (p=fini_head; p; p=p->fini_next) {
1391 while (p->ctor_visitor && p->ctor_visitor!=self)
1392 pthread_cond_wait(&ctor_cond, &init_fini_lock);
1393 if (!p->constructed) continue;
1394 decode_vec(p->dynv, dyn, DYN_CNT);
1395 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1396 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1397 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1398 while (n--) ((void (*)(void))*--fn)();
1399 }
1400 #ifndef NO_LEGACY_INITFINI
1401 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1402 fpaddr(p, dyn[DT_FINI])();
1403 #endif
1404 }
1405 }
1406
1407 static struct dso **queue_ctors(struct dso *dso)
1408 {
1409 size_t cnt, qpos, spos, i;
1410 struct dso *p, **queue, **stack;
1411
1412 if (ldd_mode) return 0;
1413
1414 /* Bound on queue size is the total number of indirect deps.
1415 * If a bfs deps list was built, we can use it. Otherwise,
1416 * bound by the total number of DSOs, which is always safe and
1417 * is reasonable we use it (for main app at startup). */
1418 if (dso->bfs_built) {
1419 for (cnt=0; dso->deps[cnt]; cnt++)
1420 dso->deps[cnt]->mark = 0;
1421 cnt++; /* self, not included in deps */
1422 } else {
1423 for (cnt=0, p=head; p; cnt++, p=p->next)
1424 p->mark = 0;
1425 }
1426 cnt++; /* termination slot */
1427 if (dso==head && cnt <= countof(builtin_ctor_queue))
1428 queue = builtin_ctor_queue;
1429 else
1430 queue = calloc(cnt, sizeof *queue);
1431
1432 if (!queue) {
1433 error("Error allocating constructor queue: %m\n");
1434 if (runtime) longjmp(*rtld_fail, 1);
1435 return 0;
1436 }
1437
1438 /* Opposite ends of the allocated buffer serve as an output queue
1439 * and a working stack. Setup initial stack with just the argument
1440 * dso and initial queue empty... */
1441 stack = queue;
1442 qpos = 0;
1443 spos = cnt;
1444 stack[--spos] = dso;
1445 dso->next_dep = 0;
1446 dso->mark = 1;
1447
1448 /* Then perform pseudo-DFS sort, but ignoring circular deps. */
1449 while (spos<cnt) {
1450 p = stack[spos++];
1451 while (p->next_dep < p->ndeps_direct) {
1452 if (p->deps[p->next_dep]->mark) {
1453 p->next_dep++;
1454 } else {
1455 stack[--spos] = p;
1456 p = p->deps[p->next_dep];
1457 p->next_dep = 0;
1458 p->mark = 1;
1459 }
1460 }
1461 queue[qpos++] = p;
1462 }
1463 queue[qpos] = 0;
1464 for (i=0; i<qpos; i++) queue[i]->mark = 0;
1465
1466 return queue;
1467 }
1468
1469 static void do_init_fini(struct dso **queue)
1470 {
1471 struct dso *p;
1472 size_t dyn[DYN_CNT], i;
1473 int self = __pthread_self()->tid;
1474
1475 pthread_mutex_lock(&init_fini_lock);
1476 for (i=0; (p=queue[i]); i++) {
1477 while ((p->ctor_visitor && p->ctor_visitor!=self) || shutting_down)
1478 pthread_cond_wait(&ctor_cond, &init_fini_lock);
1479 if (p->ctor_visitor || p->constructed)
1480 continue;
1481 p->ctor_visitor = self;
1482
1483 decode_vec(p->dynv, dyn, DYN_CNT);
1484 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1485 p->fini_next = fini_head;
1486 fini_head = p;
1487 }
1488
1489 pthread_mutex_unlock(&init_fini_lock);
1490
1491 #ifndef NO_LEGACY_INITFINI
1492 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1493 fpaddr(p, dyn[DT_INIT])();
1494 #endif
1495 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1496 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1497 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1498 while (n--) ((void (*)(void))*fn++)();
1499 }
1500
1501 pthread_mutex_lock(&init_fini_lock);
1502 p->ctor_visitor = 0;
1503 p->constructed = 1;
1504 pthread_cond_broadcast(&ctor_cond);
1505 }
1506 pthread_mutex_unlock(&init_fini_lock);
1507 }
1508
1509 void __libc_start_init(void)
1510 {
1511 do_init_fini(main_ctor_queue);
1512 if (!__malloc_replaced && main_ctor_queue != builtin_ctor_queue)
1513 free(main_ctor_queue);
1514 main_ctor_queue = 0;
1515 }
1516
1517 static void dl_debug_state(void)
1518 {
1519 }
1520
1521 weak_alias(dl_debug_state, _dl_debug_state);
1522
1523 void __init_tls(size_t *auxv)
1524 {
1525 }
1526
1527 static void update_tls_size()
1528 {
1529 libc.tls_cnt = tls_cnt;
1530 libc.tls_align = tls_align;
1531 libc.tls_size = ALIGN(
1532 (1+tls_cnt) * sizeof(void *) +
1533 tls_offset +
1534 sizeof(struct pthread) +
1535 tls_align * 2,
1536 tls_align);
1537 }
1538
1539 static void install_new_tls(void)
1540 {
1541 sigset_t set;
1542 pthread_t self = __pthread_self(), td;
1543 struct dso *dtv_provider = container_of(tls_tail, struct dso, tls);
1544 uintptr_t (*newdtv)[tls_cnt+1] = (void *)dtv_provider->new_dtv;
1545 struct dso *p;
1546 size_t i, j;
1547 size_t old_cnt = self->dtv[0];
1548
1549 __block_app_sigs(&set);
1550 __tl_lock();
1551 /* Copy existing dtv contents from all existing threads. */
1552 for (i=0, td=self; !i || td!=self; i++, td=td->next) {
1553 memcpy(newdtv+i, td->dtv,
1554 (old_cnt+1)*sizeof(uintptr_t));
1555 newdtv[i][0] = tls_cnt;
1556 }
1557 /* Install new dtls into the enlarged, uninstalled dtv copies. */
1558 for (p=head; ; p=p->next) {
1559 if (p->tls_id <= old_cnt) continue;
1560 unsigned char *mem = p->new_tls;
1561 for (j=0; j<i; j++) {
1562 unsigned char *new = mem;
1563 new += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1564 & (p->tls.align-1);
1565 memcpy(new, p->tls.image, p->tls.len);
1566 newdtv[j][p->tls_id] =
1567 (uintptr_t)new + DTP_OFFSET;
1568 mem += p->tls.size + p->tls.align;
1569 }
1570 if (p->tls_id == tls_cnt) break;
1571 }
1572
1573 /* Broadcast barrier to ensure contents of new dtv is visible
1574 * if the new dtv pointer is. The __membarrier function has a
1575 * fallback emulation using signals for kernels that lack the
1576 * feature at the syscall level. */
1577
1578 __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED, 0);
1579
1580 /* Install new dtv for each thread. */
1581 for (j=0, td=self; !j || td!=self; j++, td=td->next) {
1582 td->dtv = td->dtv_copy = newdtv[j];
1583 }
1584
1585 __tl_unlock();
1586 __restore_sigs(&set);
1587 }
1588
1589 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1590 * following stage 2 and stage 3 functions via primitive symbolic lookup
1591 * since it does not have access to their addresses to begin with. */
1592
1593 /* Stage 2 of the dynamic linker is called after relative relocations
1594 * have been processed. It can make function calls to static functions
1595 * and access string literals and static data, but cannot use extern
1596 * symbols. Its job is to perform symbolic relocations on the dynamic
1597 * linker itself, but some of the relocations performed may need to be
1598 * replaced later due to copy relocations in the main program. */
1599
1600 hidden void __dls2(unsigned char *base, size_t *sp)
1601 {
1602 size_t *auxv;
1603 for (auxv=sp+1+*sp+1; *auxv; auxv++);
1604 auxv++;
1605 if (DL_FDPIC) {
1606 void *p1 = (void *)sp[-2];
1607 void *p2 = (void *)sp[-1];
1608 if (!p1) {
1609 size_t aux[AUX_CNT];
1610 decode_vec(auxv, aux, AUX_CNT);
1611 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1612 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1613 }
1614 app_loadmap = p2 ? p1 : 0;
1615 ldso.loadmap = p2 ? p2 : p1;
1616 ldso.base = laddr(&ldso, 0);
1617 } else {
1618 ldso.base = base;
1619 }
1620 Ehdr *ehdr = (void *)ldso.base;
1621 ldso.name = ldso.shortname = "libc.so";
1622 ldso.phnum = ehdr->e_phnum;
1623 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1624 ldso.phentsize = ehdr->e_phentsize;
1625 kernel_mapped_dso(&ldso);
1626 decode_dyn(&ldso);
1627
1628 if (DL_FDPIC) makefuncdescs(&ldso);
1629
1630 /* Prepare storage for to save clobbered REL addends so they
1631 * can be reused in stage 3. There should be very few. If
1632 * something goes wrong and there are a huge number, abort
1633 * instead of risking stack overflow. */
1634 size_t dyn[DYN_CNT];
1635 decode_vec(ldso.dynv, dyn, DYN_CNT);
1636 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1637 size_t rel_size = dyn[DT_RELSZ];
1638 size_t symbolic_rel_cnt = 0;
1639 apply_addends_to = rel;
1640 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1641 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1642 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1643 size_t addends[symbolic_rel_cnt+1];
1644 saved_addends = addends;
1645
1646 head = &ldso;
1647 reloc_all(&ldso);
1648
1649 ldso.relocated = 0;
1650
1651 /* Call dynamic linker stage-2b, __dls2b, looking it up
1652 * symbolically as a barrier against moving the address
1653 * load across the above relocation processing. */
1654 struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0);
1655 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp, auxv);
1656 else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp, auxv);
1657 }
1658
1659 /* Stage 2b sets up a valid thread pointer, which requires relocations
1660 * completed in stage 2, and on which stage 3 is permitted to depend.
1661 * This is done as a separate stage, with symbolic lookup as a barrier,
1662 * so that loads of the thread pointer and &errno can be pure/const and
1663 * thereby hoistable. */
1664
1665 void __dls2b(size_t *sp, size_t *auxv)
1666 {
1667 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1668 * use during dynamic linking. If possible it will also serve as the
1669 * thread pointer at runtime. */
1670 search_vec(auxv, &__hwcap, AT_HWCAP);
1671 libc.auxv = auxv;
1672 libc.tls_size = sizeof builtin_tls;
1673 libc.tls_align = tls_align;
1674 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1675 a_crash();
1676 }
1677
1678 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1679 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp, auxv);
1680 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp, auxv);
1681 }
1682
1683 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1684 * fully functional. Its job is to load (if not already loaded) and
1685 * process dependencies and relocations for the main application and
1686 * transfer control to its entry point. */
1687
1688 void __dls3(size_t *sp, size_t *auxv)
1689 {
1690 static struct dso app, vdso;
1691 size_t aux[AUX_CNT];
1692 size_t i;
1693 char *env_preload=0;
1694 char *replace_argv0=0;
1695 size_t vdso_base;
1696 int argc = *sp;
1697 char **argv = (void *)(sp+1);
1698 char **argv_orig = argv;
1699 char **envp = argv+argc+1;
1700
1701 /* Find aux vector just past environ[] and use it to initialize
1702 * global data that may be needed before we can make syscalls. */
1703 __environ = envp;
1704 decode_vec(auxv, aux, AUX_CNT);
1705 search_vec(auxv, &__sysinfo, AT_SYSINFO);
1706 __pthread_self()->sysinfo = __sysinfo;
1707 libc.page_size = aux[AT_PAGESZ];
1708 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1709 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1710
1711 /* Only trust user/env if kernel says we're not suid/sgid */
1712 if (!libc.secure) {
1713 env_path = getenv("LD_LIBRARY_PATH");
1714 env_preload = getenv("LD_PRELOAD");
1715 }
1716
1717 /* If the main program was already loaded by the kernel,
1718 * AT_PHDR will point to some location other than the dynamic
1719 * linker's program headers. */
1720 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1721 size_t interp_off = 0;
1722 size_t tls_image = 0;
1723 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1724 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1725 app.phnum = aux[AT_PHNUM];
1726 app.phentsize = aux[AT_PHENT];
1727 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1728 if (phdr->p_type == PT_PHDR)
1729 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1730 else if (phdr->p_type == PT_INTERP)
1731 interp_off = (size_t)phdr->p_vaddr;
1732 else if (phdr->p_type == PT_TLS) {
1733 tls_image = phdr->p_vaddr;
1734 app.tls.len = phdr->p_filesz;
1735 app.tls.size = phdr->p_memsz;
1736 app.tls.align = phdr->p_align;
1737 }
1738 }
1739 if (DL_FDPIC) app.loadmap = app_loadmap;
1740 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1741 if (interp_off) ldso.name = laddr(&app, interp_off);
1742 if ((aux[0] & (1UL<<AT_EXECFN))
1743 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1744 app.name = (char *)aux[AT_EXECFN];
1745 else
1746 app.name = argv[0];
1747 kernel_mapped_dso(&app);
1748 } else {
1749 int fd;
1750 char *ldname = argv[0];
1751 size_t l = strlen(ldname);
1752 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1753 argv++;
1754 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1755 char *opt = argv[0]+2;
1756 *argv++ = (void *)-1;
1757 if (!*opt) {
1758 break;
1759 } else if (!memcmp(opt, "list", 5)) {
1760 ldd_mode = 1;
1761 } else if (!memcmp(opt, "library-path", 12)) {
1762 if (opt[12]=='=') env_path = opt+13;
1763 else if (opt[12]) *argv = 0;
1764 else if (*argv) env_path = *argv++;
1765 } else if (!memcmp(opt, "preload", 7)) {
1766 if (opt[7]=='=') env_preload = opt+8;
1767 else if (opt[7]) *argv = 0;
1768 else if (*argv) env_preload = *argv++;
1769 } else if (!memcmp(opt, "argv0", 5)) {
1770 if (opt[5]=='=') replace_argv0 = opt+6;
1771 else if (opt[5]) *argv = 0;
1772 else if (*argv) replace_argv0 = *argv++;
1773 } else {
1774 argv[0] = 0;
1775 }
1776 }
1777 argv[-1] = (void *)(argc - (argv-argv_orig));
1778 if (!argv[0]) {
1779 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1780 "Version %s\n"
1781 "Dynamic Program Loader\n"
1782 "Usage: %s [options] [--] pathname%s\n",
1783 __libc_version, ldname,
1784 ldd_mode ? "" : " [args]");
1785 _exit(1);
1786 }
1787 fd = open(argv[0], O_RDONLY);
1788 if (fd < 0) {
1789 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1790 _exit(1);
1791 }
1792 Ehdr *ehdr = (void *)map_library(fd, &app);
1793 if (!ehdr) {
1794 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1795 _exit(1);
1796 }
1797 close(fd);
1798 ldso.name = ldname;
1799 app.name = argv[0];
1800 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1801 /* Find the name that would have been used for the dynamic
1802 * linker had ldd not taken its place. */
1803 if (ldd_mode) {
1804 for (i=0; i<app.phnum; i++) {
1805 if (app.phdr[i].p_type == PT_INTERP)
1806 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1807 }
1808 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1809 }
1810 }
1811 if (app.tls.size) {
1812 libc.tls_head = tls_tail = &app.tls;
1813 app.tls_id = tls_cnt = 1;
1814 #ifdef TLS_ABOVE_TP
1815 app.tls.offset = GAP_ABOVE_TP;
1816 app.tls.offset += (-GAP_ABOVE_TP + (uintptr_t)app.tls.image)
1817 & (app.tls.align-1);
1818 tls_offset = app.tls.offset + app.tls.size;
1819 #else
1820 tls_offset = app.tls.offset = app.tls.size
1821 + ( -((uintptr_t)app.tls.image + app.tls.size)
1822 & (app.tls.align-1) );
1823 #endif
1824 tls_align = MAXP2(tls_align, app.tls.align);
1825 }
1826 decode_dyn(&app);
1827 if (DL_FDPIC) {
1828 makefuncdescs(&app);
1829 if (!app.loadmap) {
1830 app.loadmap = (void *)&app_dummy_loadmap;
1831 app.loadmap->nsegs = 1;
1832 app.loadmap->segs[0].addr = (size_t)app.map;
1833 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1834 - (size_t)app.base;
1835 app.loadmap->segs[0].p_memsz = app.map_len;
1836 }
1837 argv[-3] = (void *)app.loadmap;
1838 }
1839
1840 /* Initial dso chain consists only of the app. */
1841 head = tail = syms_tail = &app;
1842
1843 /* Donate unused parts of app and library mapping to malloc */
1844 reclaim_gaps(&app);
1845 reclaim_gaps(&ldso);
1846
1847 /* Load preload/needed libraries, add symbols to global namespace. */
1848 ldso.deps = (struct dso **)no_deps;
1849 if (env_preload) load_preload(env_preload);
1850 load_deps(&app);
1851 for (struct dso *p=head; p; p=p->next)
1852 add_syms(p);
1853
1854 /* Attach to vdso, if provided by the kernel, last so that it does
1855 * not become part of the global namespace. */
1856 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1857 Ehdr *ehdr = (void *)vdso_base;
1858 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1859 vdso.phnum = ehdr->e_phnum;
1860 vdso.phentsize = ehdr->e_phentsize;
1861 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1862 if (phdr->p_type == PT_DYNAMIC)
1863 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1864 if (phdr->p_type == PT_LOAD)
1865 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1866 }
1867 vdso.name = "";
1868 vdso.shortname = "linux-gate.so.1";
1869 vdso.relocated = 1;
1870 vdso.deps = (struct dso **)no_deps;
1871 decode_dyn(&vdso);
1872 vdso.prev = tail;
1873 tail->next = &vdso;
1874 tail = &vdso;
1875 }
1876
1877 for (i=0; app.dynv[i]; i+=2) {
1878 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1879 app.dynv[i+1] = (size_t)&debug;
1880 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1881 size_t *ptr = (size_t *) app.dynv[i+1];
1882 *ptr = (size_t)&debug;
1883 }
1884 }
1885
1886 /* This must be done before final relocations, since it calls
1887 * malloc, which may be provided by the application. Calling any
1888 * application code prior to the jump to its entry point is not
1889 * valid in our model and does not work with FDPIC, where there
1890 * are additional relocation-like fixups that only the entry point
1891 * code can see to perform. */
1892 main_ctor_queue = queue_ctors(&app);
1893
1894 /* Initial TLS must also be allocated before final relocations
1895 * might result in calloc being a call to application code. */
1896 update_tls_size();
1897 void *initial_tls = builtin_tls;
1898 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1899 initial_tls = calloc(libc.tls_size, 1);
1900 if (!initial_tls) {
1901 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1902 argv[0], libc.tls_size);
1903 _exit(127);
1904 }
1905 }
1906 static_tls_cnt = tls_cnt;
1907
1908 /* The main program must be relocated LAST since it may contain
1909 * copy relocations which depend on libraries' relocations. */
1910 reloc_all(app.next);
1911 reloc_all(&app);
1912
1913 /* Actual copying to new TLS needs to happen after relocations,
1914 * since the TLS images might have contained relocated addresses. */
1915 if (initial_tls != builtin_tls) {
1916 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1917 a_crash();
1918 }
1919 } else {
1920 size_t tmp_tls_size = libc.tls_size;
1921 pthread_t self = __pthread_self();
1922 /* Temporarily set the tls size to the full size of
1923 * builtin_tls so that __copy_tls will use the same layout
1924 * as it did for before. Then check, just to be safe. */
1925 libc.tls_size = sizeof builtin_tls;
1926 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1927 libc.tls_size = tmp_tls_size;
1928 }
1929
1930 if (ldso_fail) _exit(127);
1931 if (ldd_mode) _exit(0);
1932
1933 /* Determine if malloc was interposed by a replacement implementation
1934 * so that calloc and the memalign family can harden against the
1935 * possibility of incomplete replacement. */
1936 if (find_sym(head, "malloc", 1).dso != &ldso)
1937 __malloc_replaced = 1;
1938 if (find_sym(head, "aligned_alloc", 1).dso != &ldso)
1939 __aligned_alloc_replaced = 1;
1940
1941 /* Switch to runtime mode: any further failures in the dynamic
1942 * linker are a reportable failure rather than a fatal startup
1943 * error. */
1944 runtime = 1;
1945
1946 debug.ver = 1;
1947 debug.bp = dl_debug_state;
1948 debug.head = head;
1949 debug.base = ldso.base;
1950 debug.state = 0;
1951 _dl_debug_state();
1952
1953 if (replace_argv0) argv[0] = replace_argv0;
1954
1955 errno = 0;
1956
1957 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1958 for(;;);
1959 }
1960
1961 static void prepare_lazy(struct dso *p)
1962 {
1963 size_t dyn[DYN_CNT], n, flags1=0;
1964 decode_vec(p->dynv, dyn, DYN_CNT);
1965 search_vec(p->dynv, &flags1, DT_FLAGS_1);
1966 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1967 return;
1968 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1969 if (NEED_MIPS_GOT_RELOCS) {
1970 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1971 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1972 n += i-j;
1973 }
1974 p->lazy = calloc(n, 3*sizeof(size_t));
1975 if (!p->lazy) {
1976 error("Error preparing lazy relocation for %s: %m", p->name);
1977 longjmp(*rtld_fail, 1);
1978 }
1979 p->lazy_next = lazy_head;
1980 lazy_head = p;
1981 }
1982
1983 void *dlopen(const char *file, int mode)
1984 {
1985 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1986 struct tls_module *orig_tls_tail;
1987 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1988 size_t i;
1989 int cs;
1990 jmp_buf jb;
1991 struct dso **volatile ctor_queue = 0;
1992
1993 if (!file) return head;
1994
1995 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1996 pthread_rwlock_wrlock(&lock);
1997 __inhibit_ptc();
1998
1999 p = 0;
2000 if (shutting_down) {
2001 error("Cannot dlopen while program is exiting.");
2002 goto end;
2003 }
2004 orig_tls_tail = tls_tail;
2005 orig_tls_cnt = tls_cnt;
2006 orig_tls_offset = tls_offset;
2007 orig_tls_align = tls_align;
2008 orig_lazy_head = lazy_head;
2009 orig_syms_tail = syms_tail;
2010 orig_tail = tail;
2011 noload = mode & RTLD_NOLOAD;
2012
2013 rtld_fail = &jb;
2014 if (setjmp(*rtld_fail)) {
2015 /* Clean up anything new that was (partially) loaded */
2016 revert_syms(orig_syms_tail);
2017 for (p=orig_tail->next; p; p=next) {
2018 next = p->next;
2019 while (p->td_index) {
2020 void *tmp = p->td_index->next;
2021 free(p->td_index);
2022 p->td_index = tmp;
2023 }
2024 free(p->funcdescs);
2025 if (p->rpath != p->rpath_orig)
2026 free(p->rpath);
2027 free(p->deps);
2028 unmap_library(p);
2029 free(p);
2030 }
2031 free(ctor_queue);
2032 ctor_queue = 0;
2033 if (!orig_tls_tail) libc.tls_head = 0;
2034 tls_tail = orig_tls_tail;
2035 if (tls_tail) tls_tail->next = 0;
2036 tls_cnt = orig_tls_cnt;
2037 tls_offset = orig_tls_offset;
2038 tls_align = orig_tls_align;
2039 lazy_head = orig_lazy_head;
2040 tail = orig_tail;
2041 tail->next = 0;
2042 p = 0;
2043 goto end;
2044 } else p = load_library(file, head);
2045
2046 if (!p) {
2047 error(noload ?
2048 "Library %s is not already loaded" :
2049 "Error loading shared library %s: %m",
2050 file);
2051 goto end;
2052 }
2053
2054 /* First load handling */
2055 load_deps(p);
2056 extend_bfs_deps(p);
2057 pthread_mutex_lock(&init_fini_lock);
2058 if (!p->constructed) ctor_queue = queue_ctors(p);
2059 pthread_mutex_unlock(&init_fini_lock);
2060 if (!p->relocated && (mode & RTLD_LAZY)) {
2061 prepare_lazy(p);
2062 for (i=0; p->deps[i]; i++)
2063 if (!p->deps[i]->relocated)
2064 prepare_lazy(p->deps[i]);
2065 }
2066 if (!p->relocated || (mode & RTLD_GLOBAL)) {
2067 /* Make new symbols global, at least temporarily, so we can do
2068 * relocations. If not RTLD_GLOBAL, this is reverted below. */
2069 add_syms(p);
2070 for (i=0; p->deps[i]; i++)
2071 add_syms(p->deps[i]);
2072 }
2073 if (!p->relocated) {
2074 reloc_all(p);
2075 }
2076
2077 /* If RTLD_GLOBAL was not specified, undo any new additions
2078 * to the global symbol table. This is a nop if the library was
2079 * previously loaded and already global. */
2080 if (!(mode & RTLD_GLOBAL))
2081 revert_syms(orig_syms_tail);
2082
2083 /* Processing of deferred lazy relocations must not happen until
2084 * the new libraries are committed; otherwise we could end up with
2085 * relocations resolved to symbol definitions that get removed. */
2086 redo_lazy_relocs();
2087
2088 update_tls_size();
2089 if (tls_cnt != orig_tls_cnt)
2090 install_new_tls();
2091 _dl_debug_state();
2092 orig_tail = tail;
2093 end:
2094 __release_ptc();
2095 if (p) gencnt++;
2096 pthread_rwlock_unlock(&lock);
2097 if (ctor_queue) {
2098 do_init_fini(ctor_queue);
2099 free(ctor_queue);
2100 }
2101 pthread_setcancelstate(cs, 0);
2102 return p;
2103 }
2104
2105 hidden int __dl_invalid_handle(void *h)
2106 {
2107 struct dso *p;
2108 for (p=head; p; p=p->next) if (h==p) return 0;
2109 error("Invalid library handle %p", (void *)h);
2110 return 1;
2111 }
2112
2113 static void *addr2dso(size_t a)
2114 {
2115 struct dso *p;
2116 size_t i;
2117 if (DL_FDPIC) for (p=head; p; p=p->next) {
2118 i = count_syms(p);
2119 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
2120 return p;
2121 }
2122 for (p=head; p; p=p->next) {
2123 if (DL_FDPIC && p->loadmap) {
2124 for (i=0; i<p->loadmap->nsegs; i++) {
2125 if (a-p->loadmap->segs[i].p_vaddr
2126 < p->loadmap->segs[i].p_memsz)
2127 return p;
2128 }
2129 } else {
2130 Phdr *ph = p->phdr;
2131 size_t phcnt = p->phnum;
2132 size_t entsz = p->phentsize;
2133 size_t base = (size_t)p->base;
2134 for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
2135 if (ph->p_type != PT_LOAD) continue;
2136 if (a-base-ph->p_vaddr < ph->p_memsz)
2137 return p;
2138 }
2139 if (a-(size_t)p->map < p->map_len)
2140 return 0;
2141 }
2142 }
2143 return 0;
2144 }
2145
2146 static void *do_dlsym(struct dso *p, const char *s, void *ra)
2147 {
2148 int use_deps = 0;
2149 if (p == head || p == RTLD_DEFAULT) {
2150 p = head;
2151 } else if (p == RTLD_NEXT) {
2152 p = addr2dso((size_t)ra);
2153 if (!p) p=head;
2154 p = p->next;
2155 } else if (__dl_invalid_handle(p)) {
2156 return 0;
2157 } else
2158 use_deps = 1;
2159 struct symdef def = find_sym2(p, s, 0, use_deps);
2160 if (!def.sym) {
2161 error("Symbol not found: %s", s);
2162 return 0;
2163 }
2164 if ((def.sym->st_info&0xf) == STT_TLS)
2165 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
2166 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
2167 return def.dso->funcdescs + (def.sym - def.dso->syms);
2168 return laddr(def.dso, def.sym->st_value);
2169 }
2170
2171 int dladdr(const void *addr_arg, Dl_info *info)
2172 {
2173 size_t addr = (size_t)addr_arg;
2174 struct dso *p;
2175 Sym *sym, *bestsym;
2176 uint32_t nsym;
2177 char *strings;
2178 size_t best = 0;
2179 size_t besterr = -1;
2180
2181 pthread_rwlock_rdlock(&lock);
2182 p = addr2dso(addr);
2183 pthread_rwlock_unlock(&lock);
2184
2185 if (!p) return 0;
2186
2187 sym = p->syms;
2188 strings = p->strings;
2189 nsym = count_syms(p);
2190
2191 if (DL_FDPIC) {
2192 size_t idx = (addr-(size_t)p->funcdescs)
2193 / sizeof(*p->funcdescs);
2194 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
2195 best = (size_t)(p->funcdescs + idx);
2196 bestsym = sym + idx;
2197 besterr = 0;
2198 }
2199 }
2200
2201 if (!best) for (; nsym; nsym--, sym++) {
2202 if (sym->st_value
2203 && (1<<(sym->st_info&0xf) & OK_TYPES)
2204 && (1<<(sym->st_info>>4) & OK_BINDS)) {
2205 size_t symaddr = (size_t)laddr(p, sym->st_value);
2206 if (symaddr > addr || symaddr <= best)
2207 continue;
2208 best = symaddr;
2209 bestsym = sym;
2210 besterr = addr - symaddr;
2211 if (addr == symaddr)
2212 break;
2213 }
2214 }
2215
2216 if (best && besterr > bestsym->st_size-1) {
2217 best = 0;
2218 bestsym = 0;
2219 }
2220
2221 info->dli_fname = p->name;
2222 info->dli_fbase = p->map;
2223
2224 if (!best) {
2225 info->dli_sname = 0;
2226 info->dli_saddr = 0;
2227 return 1;
2228 }
2229
2230 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2231 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2232 info->dli_sname = strings + bestsym->st_name;
2233 info->dli_saddr = (void *)best;
2234
2235 return 1;
2236 }
2237
2238 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2239 {
2240 void *res;
2241 pthread_rwlock_rdlock(&lock);
2242 res = do_dlsym(p, s, ra);
2243 pthread_rwlock_unlock(&lock);
2244 return res;
2245 }
2246
2247 hidden void *__dlsym_redir_time64(void *restrict p, const char *restrict s, void *restrict ra)
2248 {
2249 #if _REDIR_TIME64
2250 const char *suffix, *suffix2 = "";
2251 char redir[36];
2252
2253 /* Map the symbol name to a time64 version of itself according to the
2254 * pattern used for naming the redirected time64 symbols. */
2255 size_t l = strnlen(s, sizeof redir);
2256 if (l<4 || l==sizeof redir) goto no_redir;
2257 if (s[l-2]=='_' && s[l-1]=='r') {
2258 l -= 2;
2259 suffix2 = s+l;
2260 }
2261 if (l<4) goto no_redir;
2262 if (!strcmp(s+l-4, "time")) suffix = "64";
2263 else suffix = "_time64";
2264
2265 /* Use the presence of the remapped symbol name in libc to determine
2266 * whether it's one that requires time64 redirection; replace if so. */
2267 snprintf(redir, sizeof redir, "__%.*s%s%s", (int)l, s, suffix, suffix2);
2268 if (find_sym(&ldso, redir, 1).sym) s = redir;
2269 no_redir:
2270 #endif
2271 return __dlsym(p, s, ra);
2272 }
2273
2274 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2275 {
2276 struct dso *current;
2277 struct dl_phdr_info info;
2278 int ret = 0;
2279 for(current = head; current;) {
2280 info.dlpi_addr = (uintptr_t)current->base;
2281 info.dlpi_name = current->name;
2282 info.dlpi_phdr = current->phdr;
2283 info.dlpi_phnum = current->phnum;
2284 info.dlpi_adds = gencnt;
2285 info.dlpi_subs = 0;
2286 info.dlpi_tls_modid = current->tls_id;
2287 info.dlpi_tls_data = current->tls.image;
2288
2289 ret = (callback)(&info, sizeof (info), data);
2290
2291 if (ret != 0) break;
2292
2293 pthread_rwlock_rdlock(&lock);
2294 current = current->next;
2295 pthread_rwlock_unlock(&lock);
2296 }
2297 return ret;
2298 }
2299
2300 static void error(const char *fmt, ...)
2301 {
2302 va_list ap;
2303 va_start(ap, fmt);
2304 if (!runtime) {
2305 vdprintf(2, fmt, ap);
2306 dprintf(2, "\n");
2307 ldso_fail = 1;
2308 va_end(ap);
2309 return;
2310 }
2311 __dl_vseterr(fmt, ap);
2312 va_end(ap);
2313 }
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