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fix issues from public functions defined without declaration visible
[musl.git] / ldso / dynlink.c
blobb46cbafb973fa77d9252bf030a1969594b6552ab
1 #define _GNU_SOURCE
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <stdarg.h>
5 #include <stddef.h>
6 #include <string.h>
7 #include <unistd.h>
8 #include <stdint.h>
9 #include <elf.h>
10 #include <sys/mman.h>
11 #include <limits.h>
12 #include <fcntl.h>
13 #include <sys/stat.h>
14 #include <errno.h>
15 #include <link.h>
16 #include <setjmp.h>
17 #include <pthread.h>
18 #include <ctype.h>
19 #include <dlfcn.h>
20 #include "pthread_impl.h"
21 #include "libc.h"
22 #include "dynlink.h"
23
24 static void error(const char *, ...);
25
26 #define MAXP2(a,b) (-(-(a)&-(b)))
27 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
28
29 struct debug {
30 int ver;
31 void *head;
32 void (*bp)(void);
33 int state;
34 void *base;
35 };
36
37 struct td_index {
38 size_t args[2];
39 struct td_index *next;
40 };
41
42 struct dso {
43 #if DL_FDPIC
44 struct fdpic_loadmap *loadmap;
45 #else
46 unsigned char *base;
47 #endif
48 char *name;
49 size_t *dynv;
50 struct dso *next, *prev;
51
52 Phdr *phdr;
53 int phnum;
54 size_t phentsize;
55 Sym *syms;
56 Elf_Symndx *hashtab;
57 uint32_t *ghashtab;
58 int16_t *versym;
59 char *strings;
60 struct dso *syms_next, *lazy_next;
61 size_t *lazy, lazy_cnt;
62 unsigned char *map;
63 size_t map_len;
64 dev_t dev;
65 ino_t ino;
66 char relocated;
67 char constructed;
68 char kernel_mapped;
69 struct dso **deps, *needed_by;
70 char *rpath_orig, *rpath;
71 struct tls_module tls;
72 size_t tls_id;
73 size_t relro_start, relro_end;
74 void **new_dtv;
75 unsigned char *new_tls;
76 volatile int new_dtv_idx, new_tls_idx;
77 struct td_index *td_index;
78 struct dso *fini_next;
79 char *shortname;
80 #if DL_FDPIC
81 unsigned char *base;
82 #else
83 struct fdpic_loadmap *loadmap;
84 #endif
85 struct funcdesc {
86 void *addr;
87 size_t *got;
88 } *funcdescs;
89 size_t *got;
90 char buf[];
91 };
92
93 struct symdef {
94 Sym *sym;
95 struct dso *dso;
96 };
97
98 int __init_tp(void *);
99 void __init_libc(char **, char *);
100 void *__copy_tls(unsigned char *);
101
102 hidden const char *__libc_get_version(void);
103
104 static struct builtin_tls {
105 char c;
106 struct pthread pt;
107 void *space[16];
108 } builtin_tls[1];
109 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
110
111 #define ADDEND_LIMIT 4096
112 static size_t *saved_addends, *apply_addends_to;
113
114 static struct dso ldso;
115 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
116 static char *env_path, *sys_path;
117 static unsigned long long gencnt;
118 static int runtime;
119 static int ldd_mode;
120 static int ldso_fail;
121 static int noload;
122 static jmp_buf *rtld_fail;
123 static pthread_rwlock_t lock;
124 static struct debug debug;
125 static struct tls_module *tls_tail;
126 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
127 static size_t static_tls_cnt;
128 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
129 static struct fdpic_loadmap *app_loadmap;
130 static struct fdpic_dummy_loadmap app_dummy_loadmap;
131 static struct dso *const nodeps_dummy;
132
133 struct debug *_dl_debug_addr = &debug;
134
135 extern hidden int __malloc_replaced;
136
137 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
138
139 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
140
141 weak_alias(__init_array_start, __init_array_end);
142 weak_alias(__fini_array_start, __fini_array_end);
143
144 static int dl_strcmp(const char *l, const char *r)
145 {
146 for (; *l==*r && *l; l++, r++);
147 return *(unsigned char *)l - *(unsigned char *)r;
148 }
149 #define strcmp(l,r) dl_strcmp(l,r)
150
151 /* Compute load address for a virtual address in a given dso. */
152 #if DL_FDPIC
153 static void *laddr(const struct dso *p, size_t v)
154 {
155 size_t j=0;
156 if (!p->loadmap) return p->base + v;
157 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
158 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
159 }
160 static void *laddr_pg(const struct dso *p, size_t v)
161 {
162 size_t j=0;
163 size_t pgsz = PAGE_SIZE;
164 if (!p->loadmap) return p->base + v;
165 for (j=0; ; j++) {
166 size_t a = p->loadmap->segs[j].p_vaddr;
167 size_t b = a + p->loadmap->segs[j].p_memsz;
168 a &= -pgsz;
169 b += pgsz-1;
170 b &= -pgsz;
171 if (v-a<b-a) break;
172 }
173 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
174 }
175 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
176 laddr(p, v), (p)->got })
177 #else
178 #define laddr(p, v) (void *)((p)->base + (v))
179 #define laddr_pg(p, v) laddr(p, v)
180 #define fpaddr(p, v) ((void (*)())laddr(p, v))
181 #endif
182
183 static void decode_vec(size_t *v, size_t *a, size_t cnt)
184 {
185 size_t i;
186 for (i=0; i<cnt; i++) a[i] = 0;
187 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
188 a[0] |= 1UL<<v[0];
189 a[v[0]] = v[1];
190 }
191 }
192
193 static int search_vec(size_t *v, size_t *r, size_t key)
194 {
195 for (; v[0]!=key; v+=2)
196 if (!v[0]) return 0;
197 *r = v[1];
198 return 1;
199 }
200
201 static uint32_t sysv_hash(const char *s0)
202 {
203 const unsigned char *s = (void *)s0;
204 uint_fast32_t h = 0;
205 while (*s) {
206 h = 16*h + *s++;
207 h ^= h>>24 & 0xf0;
208 }
209 return h & 0xfffffff;
210 }
211
212 static uint32_t gnu_hash(const char *s0)
213 {
214 const unsigned char *s = (void *)s0;
215 uint_fast32_t h = 5381;
216 for (; *s; s++)
217 h += h*32 + *s;
218 return h;
219 }
220
221 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
222 {
223 size_t i;
224 Sym *syms = dso->syms;
225 Elf_Symndx *hashtab = dso->hashtab;
226 char *strings = dso->strings;
227 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
228 if ((!dso->versym || dso->versym[i] >= 0)
229 && (!strcmp(s, strings+syms[i].st_name)))
230 return syms+i;
231 }
232 return 0;
233 }
234
235 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
236 {
237 uint32_t nbuckets = hashtab[0];
238 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
239 uint32_t i = buckets[h1 % nbuckets];
240
241 if (!i) return 0;
242
243 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
244
245 for (h1 |= 1; ; i++) {
246 uint32_t h2 = *hashval++;
247 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
248 && !strcmp(s, dso->strings + dso->syms[i].st_name))
249 return dso->syms+i;
250 if (h2 & 1) break;
251 }
252
253 return 0;
254 }
255
256 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
257 {
258 const size_t *bloomwords = (const void *)(hashtab+4);
259 size_t f = bloomwords[fofs & (hashtab[2]-1)];
260 if (!(f & fmask)) return 0;
261
262 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
263 if (!(f & 1)) return 0;
264
265 return gnu_lookup(h1, hashtab, dso, s);
266 }
267
268 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
269 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
270
271 #ifndef ARCH_SYM_REJECT_UND
272 #define ARCH_SYM_REJECT_UND(s) 0
273 #endif
274
275 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
276 {
277 uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
278 size_t ghm = 1ul << gh % (8*sizeof(size_t));
279 struct symdef def = {0};
280 for (; dso; dso=dso->syms_next) {
281 Sym *sym;
282 if ((ght = dso->ghashtab)) {
283 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
284 } else {
285 if (!h) h = sysv_hash(s);
286 sym = sysv_lookup(s, h, dso);
287 }
288 if (!sym) continue;
289 if (!sym->st_shndx)
290 if (need_def || (sym->st_info&0xf) == STT_TLS
291 || ARCH_SYM_REJECT_UND(sym))
292 continue;
293 if (!sym->st_value)
294 if ((sym->st_info&0xf) != STT_TLS)
295 continue;
296 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
297 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
298 def.sym = sym;
299 def.dso = dso;
300 break;
301 }
302 return def;
303 }
304
305 hidden ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
306
307 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
308 {
309 unsigned char *base = dso->base;
310 Sym *syms = dso->syms;
311 char *strings = dso->strings;
312 Sym *sym;
313 const char *name;
314 void *ctx;
315 int type;
316 int sym_index;
317 struct symdef def;
318 size_t *reloc_addr;
319 size_t sym_val;
320 size_t tls_val;
321 size_t addend;
322 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
323
324 if (dso == &ldso) {
325 /* Only ldso's REL table needs addend saving/reuse. */
326 if (rel == apply_addends_to)
327 reuse_addends = 1;
328 skip_relative = 1;
329 }
330
331 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
332 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
333 type = R_TYPE(rel[1]);
334 if (type == REL_NONE) continue;
335 reloc_addr = laddr(dso, rel[0]);
336
337 if (stride > 2) {
338 addend = rel[2];
339 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
340 addend = 0;
341 } else if (reuse_addends) {
342 /* Save original addend in stage 2 where the dso
343 * chain consists of just ldso; otherwise read back
344 * saved addend since the inline one was clobbered. */
345 if (head==&ldso)
346 saved_addends[save_slot] = *reloc_addr;
347 addend = saved_addends[save_slot++];
348 } else {
349 addend = *reloc_addr;
350 }
351
352 sym_index = R_SYM(rel[1]);
353 if (sym_index) {
354 sym = syms + sym_index;
355 name = strings + sym->st_name;
356 ctx = type==REL_COPY ? head->syms_next : head;
357 def = (sym->st_info&0xf) == STT_SECTION
358 ? (struct symdef){ .dso = dso, .sym = sym }
359 : find_sym(ctx, name, type==REL_PLT);
360 if (!def.sym && (sym->st_shndx != SHN_UNDEF
361 || sym->st_info>>4 != STB_WEAK)) {
362 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
363 dso->lazy[3*dso->lazy_cnt+0] = rel[0];
364 dso->lazy[3*dso->lazy_cnt+1] = rel[1];
365 dso->lazy[3*dso->lazy_cnt+2] = addend;
366 dso->lazy_cnt++;
367 continue;
368 }
369 error("Error relocating %s: %s: symbol not found",
370 dso->name, name);
371 if (runtime) longjmp(*rtld_fail, 1);
372 continue;
373 }
374 } else {
375 sym = 0;
376 def.sym = 0;
377 def.dso = dso;
378 }
379
380 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
381 tls_val = def.sym ? def.sym->st_value : 0;
382
383 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
384 && runtime && def.dso->tls_id > static_tls_cnt) {
385 error("Error relocating %s: %s: initial-exec TLS "
386 "resolves to dynamic definition in %s",
387 dso->name, name, def.dso->name);
388 longjmp(*rtld_fail, 1);
389 }
390
391 switch(type) {
392 case REL_NONE:
393 break;
394 case REL_OFFSET:
395 addend -= (size_t)reloc_addr;
396 case REL_SYMBOLIC:
397 case REL_GOT:
398 case REL_PLT:
399 *reloc_addr = sym_val + addend;
400 break;
401 case REL_RELATIVE:
402 *reloc_addr = (size_t)base + addend;
403 break;
404 case REL_SYM_OR_REL:
405 if (sym) *reloc_addr = sym_val + addend;
406 else *reloc_addr = (size_t)base + addend;
407 break;
408 case REL_COPY:
409 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
410 break;
411 case REL_OFFSET32:
412 *(uint32_t *)reloc_addr = sym_val + addend
413 - (size_t)reloc_addr;
414 break;
415 case REL_FUNCDESC:
416 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
417 + (def.sym - def.dso->syms)) : 0;
418 break;
419 case REL_FUNCDESC_VAL:
420 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
421 else *reloc_addr = sym_val;
422 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
423 break;
424 case REL_DTPMOD:
425 *reloc_addr = def.dso->tls_id;
426 break;
427 case REL_DTPOFF:
428 *reloc_addr = tls_val + addend - DTP_OFFSET;
429 break;
430 #ifdef TLS_ABOVE_TP
431 case REL_TPOFF:
432 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
433 break;
434 #else
435 case REL_TPOFF:
436 *reloc_addr = tls_val - def.dso->tls.offset + addend;
437 break;
438 case REL_TPOFF_NEG:
439 *reloc_addr = def.dso->tls.offset - tls_val + addend;
440 break;
441 #endif
442 case REL_TLSDESC:
443 if (stride<3) addend = reloc_addr[1];
444 if (runtime && def.dso->tls_id > static_tls_cnt) {
445 struct td_index *new = malloc(sizeof *new);
446 if (!new) {
447 error(
448 "Error relocating %s: cannot allocate TLSDESC for %s",
449 dso->name, sym ? name : "(local)" );
450 longjmp(*rtld_fail, 1);
451 }
452 new->next = dso->td_index;
453 dso->td_index = new;
454 new->args[0] = def.dso->tls_id;
455 new->args[1] = tls_val + addend;
456 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
457 reloc_addr[1] = (size_t)new;
458 } else {
459 reloc_addr[0] = (size_t)__tlsdesc_static;
460 #ifdef TLS_ABOVE_TP
461 reloc_addr[1] = tls_val + def.dso->tls.offset
462 + TPOFF_K + addend;
463 #else
464 reloc_addr[1] = tls_val - def.dso->tls.offset
465 + addend;
466 #endif
467 }
468 break;
469 default:
470 error("Error relocating %s: unsupported relocation type %d",
471 dso->name, type);
472 if (runtime) longjmp(*rtld_fail, 1);
473 continue;
474 }
475 }
476 }
477
478 static void redo_lazy_relocs()
479 {
480 struct dso *p = lazy_head, *next;
481 lazy_head = 0;
482 for (; p; p=next) {
483 next = p->lazy_next;
484 size_t size = p->lazy_cnt*3*sizeof(size_t);
485 p->lazy_cnt = 0;
486 do_relocs(p, p->lazy, size, 3);
487 if (p->lazy_cnt) {
488 p->lazy_next = lazy_head;
489 lazy_head = p;
490 } else {
491 free(p->lazy);
492 p->lazy = 0;
493 p->lazy_next = 0;
494 }
495 }
496 }
497
498 /* A huge hack: to make up for the wastefulness of shared libraries
499 * needing at least a page of dirty memory even if they have no global
500 * data, we reclaim the gaps at the beginning and end of writable maps
501 * and "donate" them to the heap. */
502
503 static void reclaim(struct dso *dso, size_t start, size_t end)
504 {
505 void __malloc_donate(char *, char *);
506 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
507 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
508 if (start >= end) return;
509 char *base = laddr_pg(dso, start);
510 __malloc_donate(base, base+(end-start));
511 }
512
513 static void reclaim_gaps(struct dso *dso)
514 {
515 Phdr *ph = dso->phdr;
516 size_t phcnt = dso->phnum;
517
518 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
519 if (ph->p_type!=PT_LOAD) continue;
520 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
521 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
522 reclaim(dso, ph->p_vaddr+ph->p_memsz,
523 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
524 }
525 }
526
527 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
528 {
529 static int no_map_fixed;
530 char *q;
531 if (!no_map_fixed) {
532 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
533 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
534 return q;
535 no_map_fixed = 1;
536 }
537 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
538 if (flags & MAP_ANONYMOUS) {
539 memset(p, 0, n);
540 return p;
541 }
542 ssize_t r;
543 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
544 for (q=p; n; q+=r, off+=r, n-=r) {
545 r = read(fd, q, n);
546 if (r < 0 && errno != EINTR) return MAP_FAILED;
547 if (!r) {
548 memset(q, 0, n);
549 break;
550 }
551 }
552 return p;
553 }
554
555 static void unmap_library(struct dso *dso)
556 {
557 if (dso->loadmap) {
558 size_t i;
559 for (i=0; i<dso->loadmap->nsegs; i++) {
560 if (!dso->loadmap->segs[i].p_memsz)
561 continue;
562 munmap((void *)dso->loadmap->segs[i].addr,
563 dso->loadmap->segs[i].p_memsz);
564 }
565 free(dso->loadmap);
566 } else if (dso->map && dso->map_len) {
567 munmap(dso->map, dso->map_len);
568 }
569 }
570
571 static void *map_library(int fd, struct dso *dso)
572 {
573 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
574 void *allocated_buf=0;
575 size_t phsize;
576 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
577 size_t this_min, this_max;
578 size_t nsegs = 0;
579 off_t off_start;
580 Ehdr *eh;
581 Phdr *ph, *ph0;
582 unsigned prot;
583 unsigned char *map=MAP_FAILED, *base;
584 size_t dyn=0;
585 size_t tls_image=0;
586 size_t i;
587
588 ssize_t l = read(fd, buf, sizeof buf);
589 eh = buf;
590 if (l<0) return 0;
591 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
592 goto noexec;
593 phsize = eh->e_phentsize * eh->e_phnum;
594 if (phsize > sizeof buf - sizeof *eh) {
595 allocated_buf = malloc(phsize);
596 if (!allocated_buf) return 0;
597 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
598 if (l < 0) goto error;
599 if (l != phsize) goto noexec;
600 ph = ph0 = allocated_buf;
601 } else if (eh->e_phoff + phsize > l) {
602 l = pread(fd, buf+1, phsize, eh->e_phoff);
603 if (l < 0) goto error;
604 if (l != phsize) goto noexec;
605 ph = ph0 = (void *)(buf + 1);
606 } else {
607 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
608 }
609 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
610 if (ph->p_type == PT_DYNAMIC) {
611 dyn = ph->p_vaddr;
612 } else if (ph->p_type == PT_TLS) {
613 tls_image = ph->p_vaddr;
614 dso->tls.align = ph->p_align;
615 dso->tls.len = ph->p_filesz;
616 dso->tls.size = ph->p_memsz;
617 } else if (ph->p_type == PT_GNU_RELRO) {
618 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
619 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
620 }
621 if (ph->p_type != PT_LOAD) continue;
622 nsegs++;
623 if (ph->p_vaddr < addr_min) {
624 addr_min = ph->p_vaddr;
625 off_start = ph->p_offset;
626 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
627 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
628 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
629 }
630 if (ph->p_vaddr+ph->p_memsz > addr_max) {
631 addr_max = ph->p_vaddr+ph->p_memsz;
632 }
633 }
634 if (!dyn) goto noexec;
635 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
636 dso->loadmap = calloc(1, sizeof *dso->loadmap
637 + nsegs * sizeof *dso->loadmap->segs);
638 if (!dso->loadmap) goto error;
639 dso->loadmap->nsegs = nsegs;
640 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
641 if (ph->p_type != PT_LOAD) continue;
642 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
643 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
644 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
645 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
646 prot, MAP_PRIVATE,
647 fd, ph->p_offset & -PAGE_SIZE);
648 if (map == MAP_FAILED) {
649 unmap_library(dso);
650 goto error;
651 }
652 dso->loadmap->segs[i].addr = (size_t)map +
653 (ph->p_vaddr & PAGE_SIZE-1);
654 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
655 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
656 i++;
657 if (prot & PROT_WRITE) {
658 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
659 + ph->p_filesz;
660 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
661 size_t pgend = brk + ph->p_memsz - ph->p_filesz
662 + PAGE_SIZE-1 & -PAGE_SIZE;
663 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
664 pgend-pgbrk, prot,
665 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
666 -1, off_start) == MAP_FAILED)
667 goto error;
668 memset(map + brk, 0, pgbrk-brk);
669 }
670 }
671 map = (void *)dso->loadmap->segs[0].addr;
672 map_len = 0;
673 goto done_mapping;
674 }
675 addr_max += PAGE_SIZE-1;
676 addr_max &= -PAGE_SIZE;
677 addr_min &= -PAGE_SIZE;
678 off_start &= -PAGE_SIZE;
679 map_len = addr_max - addr_min + off_start;
680 /* The first time, we map too much, possibly even more than
681 * the length of the file. This is okay because we will not
682 * use the invalid part; we just need to reserve the right
683 * amount of virtual address space to map over later. */
684 map = DL_NOMMU_SUPPORT
685 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
686 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
687 : mmap((void *)addr_min, map_len, prot,
688 MAP_PRIVATE, fd, off_start);
689 if (map==MAP_FAILED) goto error;
690 dso->map = map;
691 dso->map_len = map_len;
692 /* If the loaded file is not relocatable and the requested address is
693 * not available, then the load operation must fail. */
694 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
695 errno = EBUSY;
696 goto error;
697 }
698 base = map - addr_min;
699 dso->phdr = 0;
700 dso->phnum = 0;
701 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
702 if (ph->p_type != PT_LOAD) continue;
703 /* Check if the programs headers are in this load segment, and
704 * if so, record the address for use by dl_iterate_phdr. */
705 if (!dso->phdr && eh->e_phoff >= ph->p_offset
706 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
707 dso->phdr = (void *)(base + ph->p_vaddr
708 + (eh->e_phoff-ph->p_offset));
709 dso->phnum = eh->e_phnum;
710 dso->phentsize = eh->e_phentsize;
711 }
712 this_min = ph->p_vaddr & -PAGE_SIZE;
713 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
714 off_start = ph->p_offset & -PAGE_SIZE;
715 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
716 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
717 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
718 /* Reuse the existing mapping for the lowest-address LOAD */
719 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
720 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
721 goto error;
722 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
723 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
724 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
725 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
726 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)
727 goto error;
728 }
729 }
730 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
731 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
732 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
733 && errno != ENOSYS)
734 goto error;
735 break;
736 }
737 done_mapping:
738 dso->base = base;
739 dso->dynv = laddr(dso, dyn);
740 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
741 free(allocated_buf);
742 return map;
743 noexec:
744 errno = ENOEXEC;
745 error:
746 if (map!=MAP_FAILED) unmap_library(dso);
747 free(allocated_buf);
748 return 0;
749 }
750
751 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
752 {
753 size_t l;
754 int fd;
755 for (;;) {
756 s += strspn(s, ":\n");
757 l = strcspn(s, ":\n");
758 if (l-1 >= INT_MAX) return -1;
759 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
760 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
761 switch (errno) {
762 case ENOENT:
763 case ENOTDIR:
764 case EACCES:
765 case ENAMETOOLONG:
766 break;
767 default:
768 /* Any negative value but -1 will inhibit
769 * futher path search. */
770 return -2;
771 }
772 }
773 s += l;
774 }
775 }
776
777 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
778 {
779 size_t n, l;
780 const char *s, *t, *origin;
781 char *d;
782 if (p->rpath || !p->rpath_orig) return 0;
783 if (!strchr(p->rpath_orig, '$')) {
784 p->rpath = p->rpath_orig;
785 return 0;
786 }
787 n = 0;
788 s = p->rpath_orig;
789 while ((t=strchr(s, '$'))) {
790 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
791 return 0;
792 s = t+1;
793 n++;
794 }
795 if (n > SSIZE_MAX/PATH_MAX) return 0;
796
797 if (p->kernel_mapped) {
798 /* $ORIGIN searches cannot be performed for the main program
799 * when it is suid/sgid/AT_SECURE. This is because the
800 * pathname is under the control of the caller of execve.
801 * For libraries, however, $ORIGIN can be processed safely
802 * since the library's pathname came from a trusted source
803 * (either system paths or a call to dlopen). */
804 if (libc.secure)
805 return 0;
806 l = readlink("/proc/self/exe", buf, buf_size);
807 if (l == -1) switch (errno) {
808 case ENOENT:
809 case ENOTDIR:
810 case EACCES:
811 break;
812 default:
813 return -1;
814 }
815 if (l >= buf_size)
816 return 0;
817 buf[l] = 0;
818 origin = buf;
819 } else {
820 origin = p->name;
821 }
822 t = strrchr(origin, '/');
823 if (t) {
824 l = t-origin;
825 } else {
826 /* Normally p->name will always be an absolute or relative
827 * pathname containing at least one '/' character, but in the
828 * case where ldso was invoked as a command to execute a
829 * program in the working directory, app.name may not. Fix. */
830 origin = ".";
831 l = 1;
832 }
833 /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
834 if (libc.secure && *origin != '/')
835 return 0;
836 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
837 if (!p->rpath) return -1;
838
839 d = p->rpath;
840 s = p->rpath_orig;
841 while ((t=strchr(s, '$'))) {
842 memcpy(d, s, t-s);
843 d += t-s;
844 memcpy(d, origin, l);
845 d += l;
846 /* It was determined previously that the '$' is followed
847 * either by "ORIGIN" or "{ORIGIN}". */
848 s = t + 7 + 2*(t[1]=='{');
849 }
850 strcpy(d, s);
851 return 0;
852 }
853
854 static void decode_dyn(struct dso *p)
855 {
856 size_t dyn[DYN_CNT];
857 decode_vec(p->dynv, dyn, DYN_CNT);
858 p->syms = laddr(p, dyn[DT_SYMTAB]);
859 p->strings = laddr(p, dyn[DT_STRTAB]);
860 if (dyn[0]&(1<<DT_HASH))
861 p->hashtab = laddr(p, dyn[DT_HASH]);
862 if (dyn[0]&(1<<DT_RPATH))
863 p->rpath_orig = p->strings + dyn[DT_RPATH];
864 if (dyn[0]&(1<<DT_RUNPATH))
865 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
866 if (dyn[0]&(1<<DT_PLTGOT))
867 p->got = laddr(p, dyn[DT_PLTGOT]);
868 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
869 p->ghashtab = laddr(p, *dyn);
870 if (search_vec(p->dynv, dyn, DT_VERSYM))
871 p->versym = laddr(p, *dyn);
872 }
873
874 static size_t count_syms(struct dso *p)
875 {
876 if (p->hashtab) return p->hashtab[1];
877
878 size_t nsym, i;
879 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
880 uint32_t *hashval;
881 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
882 if (buckets[i] > nsym)
883 nsym = buckets[i];
884 }
885 if (nsym) {
886 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
887 do nsym++;
888 while (!(*hashval++ & 1));
889 }
890 return nsym;
891 }
892
893 static void *dl_mmap(size_t n)
894 {
895 void *p;
896 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
897 #ifdef SYS_mmap2
898 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
899 #else
900 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
901 #endif
902 return p == MAP_FAILED ? 0 : p;
903 }
904
905 static void makefuncdescs(struct dso *p)
906 {
907 static int self_done;
908 size_t nsym = count_syms(p);
909 size_t i, size = nsym * sizeof(*p->funcdescs);
910
911 if (!self_done) {
912 p->funcdescs = dl_mmap(size);
913 self_done = 1;
914 } else {
915 p->funcdescs = malloc(size);
916 }
917 if (!p->funcdescs) {
918 if (!runtime) a_crash();
919 error("Error allocating function descriptors for %s", p->name);
920 longjmp(*rtld_fail, 1);
921 }
922 for (i=0; i<nsym; i++) {
923 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
924 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
925 p->funcdescs[i].got = p->got;
926 } else {
927 p->funcdescs[i].addr = 0;
928 p->funcdescs[i].got = 0;
929 }
930 }
931 }
932
933 static struct dso *load_library(const char *name, struct dso *needed_by)
934 {
935 char buf[2*NAME_MAX+2];
936 const char *pathname;
937 unsigned char *map;
938 struct dso *p, temp_dso = {0};
939 int fd;
940 struct stat st;
941 size_t alloc_size;
942 int n_th = 0;
943 int is_self = 0;
944
945 if (!*name) {
946 errno = EINVAL;
947 return 0;
948 }
949
950 /* Catch and block attempts to reload the implementation itself */
951 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
952 static const char reserved[] =
953 "c.pthread.rt.m.dl.util.xnet.";
954 const char *rp, *next;
955 for (rp=reserved; *rp; rp=next) {
956 next = strchr(rp, '.') + 1;
957 if (strncmp(name+3, rp, next-rp) == 0)
958 break;
959 }
960 if (*rp) {
961 if (ldd_mode) {
962 /* Track which names have been resolved
963 * and only report each one once. */
964 static unsigned reported;
965 unsigned mask = 1U<<(rp-reserved);
966 if (!(reported & mask)) {
967 reported |= mask;
968 dprintf(1, "\t%s => %s (%p)\n",
969 name, ldso.name,
970 ldso.base);
971 }
972 }
973 is_self = 1;
974 }
975 }
976 if (!strcmp(name, ldso.name)) is_self = 1;
977 if (is_self) {
978 if (!ldso.prev) {
979 tail->next = &ldso;
980 ldso.prev = tail;
981 tail = &ldso;
982 }
983 return &ldso;
984 }
985 if (strchr(name, '/')) {
986 pathname = name;
987 fd = open(name, O_RDONLY|O_CLOEXEC);
988 } else {
989 /* Search for the name to see if it's already loaded */
990 for (p=head->next; p; p=p->next) {
991 if (p->shortname && !strcmp(p->shortname, name)) {
992 return p;
993 }
994 }
995 if (strlen(name) > NAME_MAX) return 0;
996 fd = -1;
997 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
998 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
999 if (fixup_rpath(p, buf, sizeof buf) < 0)
1000 fd = -2; /* Inhibit further search. */
1001 if (p->rpath)
1002 fd = path_open(name, p->rpath, buf, sizeof buf);
1003 }
1004 if (fd == -1) {
1005 if (!sys_path) {
1006 char *prefix = 0;
1007 size_t prefix_len;
1008 if (ldso.name[0]=='/') {
1009 char *s, *t, *z;
1010 for (s=t=z=ldso.name; *s; s++)
1011 if (*s=='/') z=t, t=s;
1012 prefix_len = z-ldso.name;
1013 if (prefix_len < PATH_MAX)
1014 prefix = ldso.name;
1015 }
1016 if (!prefix) {
1017 prefix = "";
1018 prefix_len = 0;
1019 }
1020 char etc_ldso_path[prefix_len + 1
1021 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1022 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1023 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1024 (int)prefix_len, prefix);
1025 FILE *f = fopen(etc_ldso_path, "rbe");
1026 if (f) {
1027 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1028 free(sys_path);
1029 sys_path = "";
1030 }
1031 fclose(f);
1032 } else if (errno != ENOENT) {
1033 sys_path = "";
1034 }
1035 }
1036 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1037 fd = path_open(name, sys_path, buf, sizeof buf);
1038 }
1039 pathname = buf;
1040 }
1041 if (fd < 0) return 0;
1042 if (fstat(fd, &st) < 0) {
1043 close(fd);
1044 return 0;
1045 }
1046 for (p=head->next; p; p=p->next) {
1047 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1048 /* If this library was previously loaded with a
1049 * pathname but a search found the same inode,
1050 * setup its shortname so it can be found by name. */
1051 if (!p->shortname && pathname != name)
1052 p->shortname = strrchr(p->name, '/')+1;
1053 close(fd);
1054 return p;
1055 }
1056 }
1057 map = noload ? 0 : map_library(fd, &temp_dso);
1058 close(fd);
1059 if (!map) return 0;
1060
1061 /* Avoid the danger of getting two versions of libc mapped into the
1062 * same process when an absolute pathname was used. The symbols
1063 * checked are chosen to catch both musl and glibc, and to avoid
1064 * false positives from interposition-hack libraries. */
1065 decode_dyn(&temp_dso);
1066 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1067 find_sym(&temp_dso, "stdin", 1).sym) {
1068 unmap_library(&temp_dso);
1069 return load_library("libc.so", needed_by);
1070 }
1071 /* Past this point, if we haven't reached runtime yet, ldso has
1072 * committed either to use the mapped library or to abort execution.
1073 * Unmapping is not possible, so we can safely reclaim gaps. */
1074 if (!runtime) reclaim_gaps(&temp_dso);
1075
1076 /* Allocate storage for the new DSO. When there is TLS, this
1077 * storage must include a reservation for all pre-existing
1078 * threads to obtain copies of both the new TLS, and an
1079 * extended DTV capable of storing an additional slot for
1080 * the newly-loaded DSO. */
1081 alloc_size = sizeof *p + strlen(pathname) + 1;
1082 if (runtime && temp_dso.tls.image) {
1083 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1084 + sizeof(void *) * (tls_cnt+3);
1085 n_th = libc.threads_minus_1 + 1;
1086 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1087 else alloc_size += n_th * per_th;
1088 }
1089 p = calloc(1, alloc_size);
1090 if (!p) {
1091 unmap_library(&temp_dso);
1092 return 0;
1093 }
1094 memcpy(p, &temp_dso, sizeof temp_dso);
1095 p->dev = st.st_dev;
1096 p->ino = st.st_ino;
1097 p->needed_by = needed_by;
1098 p->name = p->buf;
1099 strcpy(p->name, pathname);
1100 /* Add a shortname only if name arg was not an explicit pathname. */
1101 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1102 if (p->tls.image) {
1103 p->tls_id = ++tls_cnt;
1104 tls_align = MAXP2(tls_align, p->tls.align);
1105 #ifdef TLS_ABOVE_TP
1106 p->tls.offset = tls_offset + ( (tls_align-1) &
1107 -(tls_offset + (uintptr_t)p->tls.image) );
1108 tls_offset += p->tls.size;
1109 #else
1110 tls_offset += p->tls.size + p->tls.align - 1;
1111 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1112 & (p->tls.align-1);
1113 p->tls.offset = tls_offset;
1114 #endif
1115 p->new_dtv = (void *)(-sizeof(size_t) &
1116 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1117 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1118 if (tls_tail) tls_tail->next = &p->tls;
1119 else libc.tls_head = &p->tls;
1120 tls_tail = &p->tls;
1121 }
1122
1123 tail->next = p;
1124 p->prev = tail;
1125 tail = p;
1126
1127 if (DL_FDPIC) makefuncdescs(p);
1128
1129 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1130
1131 return p;
1132 }
1133
1134 static void load_deps(struct dso *p)
1135 {
1136 size_t i, ndeps=0;
1137 struct dso ***deps = &p->deps, **tmp, *dep;
1138 for (; p; p=p->next) {
1139 for (i=0; p->dynv[i]; i+=2) {
1140 if (p->dynv[i] != DT_NEEDED) continue;
1141 dep = load_library(p->strings + p->dynv[i+1], p);
1142 if (!dep) {
1143 error("Error loading shared library %s: %m (needed by %s)",
1144 p->strings + p->dynv[i+1], p->name);
1145 if (runtime) longjmp(*rtld_fail, 1);
1146 continue;
1147 }
1148 if (runtime) {
1149 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1150 if (!tmp) longjmp(*rtld_fail, 1);
1151 tmp[ndeps++] = dep;
1152 tmp[ndeps] = 0;
1153 *deps = tmp;
1154 }
1155 }
1156 }
1157 if (!*deps) *deps = (struct dso **)&nodeps_dummy;
1158 }
1159
1160 static void load_preload(char *s)
1161 {
1162 int tmp;
1163 char *z;
1164 for (z=s; *z; s=z) {
1165 for ( ; *s && (isspace(*s) || *s==':'); s++);
1166 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1167 tmp = *z;
1168 *z = 0;
1169 load_library(s, 0);
1170 *z = tmp;
1171 }
1172 }
1173
1174 static void add_syms(struct dso *p)
1175 {
1176 if (!p->syms_next && syms_tail != p) {
1177 syms_tail->syms_next = p;
1178 syms_tail = p;
1179 }
1180 }
1181
1182 static void revert_syms(struct dso *old_tail)
1183 {
1184 struct dso *p, *next;
1185 /* Chop off the tail of the list of dsos that participate in
1186 * the global symbol table, reverting them to RTLD_LOCAL. */
1187 for (p=old_tail; p; p=next) {
1188 next = p->syms_next;
1189 p->syms_next = 0;
1190 }
1191 syms_tail = old_tail;
1192 }
1193
1194 static void do_mips_relocs(struct dso *p, size_t *got)
1195 {
1196 size_t i, j, rel[2];
1197 unsigned char *base = p->base;
1198 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1199 if (p==&ldso) {
1200 got += i;
1201 } else {
1202 while (i--) *got++ += (size_t)base;
1203 }
1204 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1205 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1206 Sym *sym = p->syms + j;
1207 rel[0] = (unsigned char *)got - base;
1208 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1209 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1210 do_relocs(p, rel, sizeof rel, 2);
1211 }
1212 }
1213
1214 static void reloc_all(struct dso *p)
1215 {
1216 size_t dyn[DYN_CNT];
1217 for (; p; p=p->next) {
1218 if (p->relocated) continue;
1219 decode_vec(p->dynv, dyn, DYN_CNT);
1220 if (NEED_MIPS_GOT_RELOCS)
1221 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1222 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1223 2+(dyn[DT_PLTREL]==DT_RELA));
1224 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1225 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1226
1227 if (head != &ldso && p->relro_start != p->relro_end &&
1228 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1229 && errno != ENOSYS) {
1230 error("Error relocating %s: RELRO protection failed: %m",
1231 p->name);
1232 if (runtime) longjmp(*rtld_fail, 1);
1233 }
1234
1235 p->relocated = 1;
1236 }
1237 }
1238
1239 static void kernel_mapped_dso(struct dso *p)
1240 {
1241 size_t min_addr = -1, max_addr = 0, cnt;
1242 Phdr *ph = p->phdr;
1243 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1244 if (ph->p_type == PT_DYNAMIC) {
1245 p->dynv = laddr(p, ph->p_vaddr);
1246 } else if (ph->p_type == PT_GNU_RELRO) {
1247 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1248 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1249 }
1250 if (ph->p_type != PT_LOAD) continue;
1251 if (ph->p_vaddr < min_addr)
1252 min_addr = ph->p_vaddr;
1253 if (ph->p_vaddr+ph->p_memsz > max_addr)
1254 max_addr = ph->p_vaddr+ph->p_memsz;
1255 }
1256 min_addr &= -PAGE_SIZE;
1257 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1258 p->map = p->base + min_addr;
1259 p->map_len = max_addr - min_addr;
1260 p->kernel_mapped = 1;
1261 }
1262
1263 void __libc_exit_fini()
1264 {
1265 struct dso *p;
1266 size_t dyn[DYN_CNT];
1267 for (p=fini_head; p; p=p->fini_next) {
1268 if (!p->constructed) continue;
1269 decode_vec(p->dynv, dyn, DYN_CNT);
1270 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1271 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1272 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1273 while (n--) ((void (*)(void))*--fn)();
1274 }
1275 #ifndef NO_LEGACY_INITFINI
1276 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1277 fpaddr(p, dyn[DT_FINI])();
1278 #endif
1279 }
1280 }
1281
1282 static void do_init_fini(struct dso *p)
1283 {
1284 size_t dyn[DYN_CNT];
1285 int need_locking = libc.threads_minus_1;
1286 /* Allow recursive calls that arise when a library calls
1287 * dlopen from one of its constructors, but block any
1288 * other threads until all ctors have finished. */
1289 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1290 for (; p; p=p->prev) {
1291 if (p->constructed) continue;
1292 p->constructed = 1;
1293 decode_vec(p->dynv, dyn, DYN_CNT);
1294 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1295 p->fini_next = fini_head;
1296 fini_head = p;
1297 }
1298 #ifndef NO_LEGACY_INITFINI
1299 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1300 fpaddr(p, dyn[DT_INIT])();
1301 #endif
1302 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1303 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1304 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1305 while (n--) ((void (*)(void))*fn++)();
1306 }
1307 if (!need_locking && libc.threads_minus_1) {
1308 need_locking = 1;
1309 pthread_mutex_lock(&init_fini_lock);
1310 }
1311 }
1312 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1313 }
1314
1315 void __libc_start_init(void)
1316 {
1317 do_init_fini(tail);
1318 }
1319
1320 static void dl_debug_state(void)
1321 {
1322 }
1323
1324 weak_alias(dl_debug_state, _dl_debug_state);
1325
1326 void __init_tls(size_t *auxv)
1327 {
1328 }
1329
1330 hidden void *__tls_get_new(tls_mod_off_t *v)
1331 {
1332 pthread_t self = __pthread_self();
1333
1334 /* Block signals to make accessing new TLS async-signal-safe */
1335 sigset_t set;
1336 __block_all_sigs(&set);
1337 if (v[0]<=(size_t)self->dtv[0]) {
1338 __restore_sigs(&set);
1339 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1340 }
1341
1342 /* This is safe without any locks held because, if the caller
1343 * is able to request the Nth entry of the DTV, the DSO list
1344 * must be valid at least that far out and it was synchronized
1345 * at program startup or by an already-completed call to dlopen. */
1346 struct dso *p;
1347 for (p=head; p->tls_id != v[0]; p=p->next);
1348
1349 /* Get new DTV space from new DSO if needed */
1350 if (v[0] > (size_t)self->dtv[0]) {
1351 void **newdtv = p->new_dtv +
1352 (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
1353 memcpy(newdtv, self->dtv,
1354 ((size_t)self->dtv[0]+1) * sizeof(void *));
1355 newdtv[0] = (void *)v[0];
1356 self->dtv = self->dtv_copy = newdtv;
1357 }
1358
1359 /* Get new TLS memory from all new DSOs up to the requested one */
1360 unsigned char *mem;
1361 for (p=head; ; p=p->next) {
1362 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1363 mem = p->new_tls + (p->tls.size + p->tls.align)
1364 * a_fetch_add(&p->new_tls_idx,1);
1365 mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1366 & (p->tls.align-1);
1367 self->dtv[p->tls_id] = mem;
1368 memcpy(mem, p->tls.image, p->tls.len);
1369 if (p->tls_id == v[0]) break;
1370 }
1371 __restore_sigs(&set);
1372 return mem + v[1] + DTP_OFFSET;
1373 }
1374
1375 static void update_tls_size()
1376 {
1377 libc.tls_cnt = tls_cnt;
1378 libc.tls_align = tls_align;
1379 libc.tls_size = ALIGN(
1380 (1+tls_cnt) * sizeof(void *) +
1381 tls_offset +
1382 sizeof(struct pthread) +
1383 tls_align * 2,
1384 tls_align);
1385 }
1386
1387 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1388 * following stage 2 and stage 3 functions via primitive symbolic lookup
1389 * since it does not have access to their addresses to begin with. */
1390
1391 /* Stage 2 of the dynamic linker is called after relative relocations
1392 * have been processed. It can make function calls to static functions
1393 * and access string literals and static data, but cannot use extern
1394 * symbols. Its job is to perform symbolic relocations on the dynamic
1395 * linker itself, but some of the relocations performed may need to be
1396 * replaced later due to copy relocations in the main program. */
1397
1398 hidden void __dls2(unsigned char *base, size_t *sp)
1399 {
1400 if (DL_FDPIC) {
1401 void *p1 = (void *)sp[-2];
1402 void *p2 = (void *)sp[-1];
1403 if (!p1) {
1404 size_t *auxv, aux[AUX_CNT];
1405 for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1406 decode_vec(auxv, aux, AUX_CNT);
1407 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1408 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1409 }
1410 app_loadmap = p2 ? p1 : 0;
1411 ldso.loadmap = p2 ? p2 : p1;
1412 ldso.base = laddr(&ldso, 0);
1413 } else {
1414 ldso.base = base;
1415 }
1416 Ehdr *ehdr = (void *)ldso.base;
1417 ldso.name = ldso.shortname = "libc.so";
1418 ldso.phnum = ehdr->e_phnum;
1419 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1420 ldso.phentsize = ehdr->e_phentsize;
1421 kernel_mapped_dso(&ldso);
1422 decode_dyn(&ldso);
1423
1424 if (DL_FDPIC) makefuncdescs(&ldso);
1425
1426 /* Prepare storage for to save clobbered REL addends so they
1427 * can be reused in stage 3. There should be very few. If
1428 * something goes wrong and there are a huge number, abort
1429 * instead of risking stack overflow. */
1430 size_t dyn[DYN_CNT];
1431 decode_vec(ldso.dynv, dyn, DYN_CNT);
1432 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1433 size_t rel_size = dyn[DT_RELSZ];
1434 size_t symbolic_rel_cnt = 0;
1435 apply_addends_to = rel;
1436 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1437 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1438 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1439 size_t addends[symbolic_rel_cnt+1];
1440 saved_addends = addends;
1441
1442 head = &ldso;
1443 reloc_all(&ldso);
1444
1445 ldso.relocated = 0;
1446
1447 /* Call dynamic linker stage-3, __dls3, looking it up
1448 * symbolically as a barrier against moving the address
1449 * load across the above relocation processing. */
1450 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1451 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1452 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1453 }
1454
1455 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1456 * fully functional. Its job is to load (if not already loaded) and
1457 * process dependencies and relocations for the main application and
1458 * transfer control to its entry point. */
1459
1460 _Noreturn void __dls3(size_t *sp)
1461 {
1462 static struct dso app, vdso;
1463 size_t aux[AUX_CNT], *auxv;
1464 size_t i;
1465 char *env_preload=0;
1466 char *replace_argv0=0;
1467 size_t vdso_base;
1468 int argc = *sp;
1469 char **argv = (void *)(sp+1);
1470 char **argv_orig = argv;
1471 char **envp = argv+argc+1;
1472
1473 /* Find aux vector just past environ[] and use it to initialize
1474 * global data that may be needed before we can make syscalls. */
1475 __environ = envp;
1476 for (i=argc+1; argv[i]; i++);
1477 libc.auxv = auxv = (void *)(argv+i+1);
1478 decode_vec(auxv, aux, AUX_CNT);
1479 __hwcap = aux[AT_HWCAP];
1480 libc.page_size = aux[AT_PAGESZ];
1481 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1482 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1483
1484 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1485 * use during dynamic linking. If possible it will also serve as the
1486 * thread pointer at runtime. */
1487 libc.tls_size = sizeof builtin_tls;
1488 libc.tls_align = tls_align;
1489 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1490 a_crash();
1491 }
1492
1493 /* Only trust user/env if kernel says we're not suid/sgid */
1494 if (!libc.secure) {
1495 env_path = getenv("LD_LIBRARY_PATH");
1496 env_preload = getenv("LD_PRELOAD");
1497 }
1498
1499 /* If the main program was already loaded by the kernel,
1500 * AT_PHDR will point to some location other than the dynamic
1501 * linker's program headers. */
1502 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1503 size_t interp_off = 0;
1504 size_t tls_image = 0;
1505 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1506 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1507 app.phnum = aux[AT_PHNUM];
1508 app.phentsize = aux[AT_PHENT];
1509 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1510 if (phdr->p_type == PT_PHDR)
1511 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1512 else if (phdr->p_type == PT_INTERP)
1513 interp_off = (size_t)phdr->p_vaddr;
1514 else if (phdr->p_type == PT_TLS) {
1515 tls_image = phdr->p_vaddr;
1516 app.tls.len = phdr->p_filesz;
1517 app.tls.size = phdr->p_memsz;
1518 app.tls.align = phdr->p_align;
1519 }
1520 }
1521 if (DL_FDPIC) app.loadmap = app_loadmap;
1522 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1523 if (interp_off) ldso.name = laddr(&app, interp_off);
1524 if ((aux[0] & (1UL<<AT_EXECFN))
1525 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1526 app.name = (char *)aux[AT_EXECFN];
1527 else
1528 app.name = argv[0];
1529 kernel_mapped_dso(&app);
1530 } else {
1531 int fd;
1532 char *ldname = argv[0];
1533 size_t l = strlen(ldname);
1534 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1535 argv++;
1536 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1537 char *opt = argv[0]+2;
1538 *argv++ = (void *)-1;
1539 if (!*opt) {
1540 break;
1541 } else if (!memcmp(opt, "list", 5)) {
1542 ldd_mode = 1;
1543 } else if (!memcmp(opt, "library-path", 12)) {
1544 if (opt[12]=='=') env_path = opt+13;
1545 else if (opt[12]) *argv = 0;
1546 else if (*argv) env_path = *argv++;
1547 } else if (!memcmp(opt, "preload", 7)) {
1548 if (opt[7]=='=') env_preload = opt+8;
1549 else if (opt[7]) *argv = 0;
1550 else if (*argv) env_preload = *argv++;
1551 } else if (!memcmp(opt, "argv0", 5)) {
1552 if (opt[5]=='=') replace_argv0 = opt+6;
1553 else if (opt[5]) *argv = 0;
1554 else if (*argv) replace_argv0 = *argv++;
1555 } else {
1556 argv[0] = 0;
1557 }
1558 }
1559 argv[-1] = (void *)(argc - (argv-argv_orig));
1560 if (!argv[0]) {
1561 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1562 "Version %s\n"
1563 "Dynamic Program Loader\n"
1564 "Usage: %s [options] [--] pathname%s\n",
1565 __libc_get_version(), ldname,
1566 ldd_mode ? "" : " [args]");
1567 _exit(1);
1568 }
1569 fd = open(argv[0], O_RDONLY);
1570 if (fd < 0) {
1571 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1572 _exit(1);
1573 }
1574 Ehdr *ehdr = (void *)map_library(fd, &app);
1575 if (!ehdr) {
1576 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1577 _exit(1);
1578 }
1579 close(fd);
1580 ldso.name = ldname;
1581 app.name = argv[0];
1582 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1583 /* Find the name that would have been used for the dynamic
1584 * linker had ldd not taken its place. */
1585 if (ldd_mode) {
1586 for (i=0; i<app.phnum; i++) {
1587 if (app.phdr[i].p_type == PT_INTERP)
1588 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1589 }
1590 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1591 }
1592 }
1593 if (app.tls.size) {
1594 libc.tls_head = tls_tail = &app.tls;
1595 app.tls_id = tls_cnt = 1;
1596 #ifdef TLS_ABOVE_TP
1597 app.tls.offset = GAP_ABOVE_TP;
1598 app.tls.offset += -GAP_ABOVE_TP & (app.tls.align-1);
1599 tls_offset = app.tls.offset + app.tls.size
1600 + ( -((uintptr_t)app.tls.image + app.tls.size)
1601 & (app.tls.align-1) );
1602 #else
1603 tls_offset = app.tls.offset = app.tls.size
1604 + ( -((uintptr_t)app.tls.image + app.tls.size)
1605 & (app.tls.align-1) );
1606 #endif
1607 tls_align = MAXP2(tls_align, app.tls.align);
1608 }
1609 decode_dyn(&app);
1610 if (DL_FDPIC) {
1611 makefuncdescs(&app);
1612 if (!app.loadmap) {
1613 app.loadmap = (void *)&app_dummy_loadmap;
1614 app.loadmap->nsegs = 1;
1615 app.loadmap->segs[0].addr = (size_t)app.map;
1616 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1617 - (size_t)app.base;
1618 app.loadmap->segs[0].p_memsz = app.map_len;
1619 }
1620 argv[-3] = (void *)app.loadmap;
1621 }
1622
1623 /* Initial dso chain consists only of the app. */
1624 head = tail = syms_tail = &app;
1625
1626 /* Donate unused parts of app and library mapping to malloc */
1627 reclaim_gaps(&app);
1628 reclaim_gaps(&ldso);
1629
1630 /* Load preload/needed libraries, add symbols to global namespace. */
1631 if (env_preload) load_preload(env_preload);
1632 load_deps(&app);
1633 for (struct dso *p=head; p; p=p->next)
1634 add_syms(p);
1635
1636 /* Attach to vdso, if provided by the kernel, last so that it does
1637 * not become part of the global namespace. */
1638 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1639 Ehdr *ehdr = (void *)vdso_base;
1640 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1641 vdso.phnum = ehdr->e_phnum;
1642 vdso.phentsize = ehdr->e_phentsize;
1643 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1644 if (phdr->p_type == PT_DYNAMIC)
1645 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1646 if (phdr->p_type == PT_LOAD)
1647 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1648 }
1649 vdso.name = "";
1650 vdso.shortname = "linux-gate.so.1";
1651 vdso.relocated = 1;
1652 decode_dyn(&vdso);
1653 vdso.prev = tail;
1654 tail->next = &vdso;
1655 tail = &vdso;
1656 }
1657
1658 for (i=0; app.dynv[i]; i+=2) {
1659 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1660 app.dynv[i+1] = (size_t)&debug;
1661 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1662 size_t *ptr = (size_t *) app.dynv[i+1];
1663 *ptr = (size_t)&debug;
1664 }
1665 }
1666
1667 /* The main program must be relocated LAST since it may contin
1668 * copy relocations which depend on libraries' relocations. */
1669 reloc_all(app.next);
1670 reloc_all(&app);
1671
1672 update_tls_size();
1673 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1674 void *initial_tls = calloc(libc.tls_size, 1);
1675 if (!initial_tls) {
1676 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1677 argv[0], libc.tls_size);
1678 _exit(127);
1679 }
1680 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1681 a_crash();
1682 }
1683 } else {
1684 size_t tmp_tls_size = libc.tls_size;
1685 pthread_t self = __pthread_self();
1686 /* Temporarily set the tls size to the full size of
1687 * builtin_tls so that __copy_tls will use the same layout
1688 * as it did for before. Then check, just to be safe. */
1689 libc.tls_size = sizeof builtin_tls;
1690 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1691 libc.tls_size = tmp_tls_size;
1692 }
1693 static_tls_cnt = tls_cnt;
1694
1695 if (ldso_fail) _exit(127);
1696 if (ldd_mode) _exit(0);
1697
1698 /* Determine if malloc was interposed by a replacement implementation
1699 * so that calloc and the memalign family can harden against the
1700 * possibility of incomplete replacement. */
1701 if (find_sym(head, "malloc", 1).dso != &ldso)
1702 __malloc_replaced = 1;
1703
1704 /* Switch to runtime mode: any further failures in the dynamic
1705 * linker are a reportable failure rather than a fatal startup
1706 * error. */
1707 runtime = 1;
1708
1709 debug.ver = 1;
1710 debug.bp = dl_debug_state;
1711 debug.head = head;
1712 debug.base = ldso.base;
1713 debug.state = 0;
1714 _dl_debug_state();
1715
1716 if (replace_argv0) argv[0] = replace_argv0;
1717
1718 errno = 0;
1719
1720 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1721 for(;;);
1722 }
1723
1724 static void prepare_lazy(struct dso *p)
1725 {
1726 size_t dyn[DYN_CNT], n, flags1=0;
1727 decode_vec(p->dynv, dyn, DYN_CNT);
1728 search_vec(p->dynv, &flags1, DT_FLAGS_1);
1729 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1730 return;
1731 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1732 if (NEED_MIPS_GOT_RELOCS) {
1733 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1734 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1735 n += i-j;
1736 }
1737 p->lazy = calloc(n, 3*sizeof(size_t));
1738 if (!p->lazy) {
1739 error("Error preparing lazy relocation for %s: %m", p->name);
1740 longjmp(*rtld_fail, 1);
1741 }
1742 p->lazy_next = lazy_head;
1743 lazy_head = p;
1744 }
1745
1746 void *dlopen(const char *file, int mode)
1747 {
1748 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1749 struct tls_module *orig_tls_tail;
1750 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1751 size_t i;
1752 int cs;
1753 jmp_buf jb;
1754
1755 if (!file) return head;
1756
1757 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1758 pthread_rwlock_wrlock(&lock);
1759 __inhibit_ptc();
1760
1761 p = 0;
1762 orig_tls_tail = tls_tail;
1763 orig_tls_cnt = tls_cnt;
1764 orig_tls_offset = tls_offset;
1765 orig_tls_align = tls_align;
1766 orig_lazy_head = lazy_head;
1767 orig_syms_tail = syms_tail;
1768 orig_tail = tail;
1769 noload = mode & RTLD_NOLOAD;
1770
1771 rtld_fail = &jb;
1772 if (setjmp(*rtld_fail)) {
1773 /* Clean up anything new that was (partially) loaded */
1774 revert_syms(orig_syms_tail);
1775 for (p=orig_tail->next; p; p=next) {
1776 next = p->next;
1777 while (p->td_index) {
1778 void *tmp = p->td_index->next;
1779 free(p->td_index);
1780 p->td_index = tmp;
1781 }
1782 free(p->funcdescs);
1783 if (p->rpath != p->rpath_orig)
1784 free(p->rpath);
1785 if (p->deps != &nodeps_dummy)
1786 free(p->deps);
1787 unmap_library(p);
1788 free(p);
1789 }
1790 if (!orig_tls_tail) libc.tls_head = 0;
1791 tls_tail = orig_tls_tail;
1792 if (tls_tail) tls_tail->next = 0;
1793 tls_cnt = orig_tls_cnt;
1794 tls_offset = orig_tls_offset;
1795 tls_align = orig_tls_align;
1796 lazy_head = orig_lazy_head;
1797 tail = orig_tail;
1798 tail->next = 0;
1799 p = 0;
1800 goto end;
1801 } else p = load_library(file, head);
1802
1803 if (!p) {
1804 error(noload ?
1805 "Library %s is not already loaded" :
1806 "Error loading shared library %s: %m",
1807 file);
1808 goto end;
1809 }
1810
1811 /* First load handling */
1812 int first_load = !p->deps;
1813 if (first_load) {
1814 load_deps(p);
1815 if (!p->relocated && (mode & RTLD_LAZY)) {
1816 prepare_lazy(p);
1817 for (i=0; p->deps[i]; i++)
1818 if (!p->deps[i]->relocated)
1819 prepare_lazy(p->deps[i]);
1820 }
1821 }
1822 if (first_load || (mode & RTLD_GLOBAL)) {
1823 /* Make new symbols global, at least temporarily, so we can do
1824 * relocations. If not RTLD_GLOBAL, this is reverted below. */
1825 add_syms(p);
1826 for (i=0; p->deps[i]; i++)
1827 add_syms(p->deps[i]);
1828 }
1829 if (first_load) {
1830 reloc_all(p);
1831 }
1832
1833 /* If RTLD_GLOBAL was not specified, undo any new additions
1834 * to the global symbol table. This is a nop if the library was
1835 * previously loaded and already global. */
1836 if (!(mode & RTLD_GLOBAL))
1837 revert_syms(orig_syms_tail);
1838
1839 /* Processing of deferred lazy relocations must not happen until
1840 * the new libraries are committed; otherwise we could end up with
1841 * relocations resolved to symbol definitions that get removed. */
1842 redo_lazy_relocs();
1843
1844 update_tls_size();
1845 _dl_debug_state();
1846 orig_tail = tail;
1847 end:
1848 __release_ptc();
1849 if (p) gencnt++;
1850 pthread_rwlock_unlock(&lock);
1851 if (p) do_init_fini(orig_tail);
1852 pthread_setcancelstate(cs, 0);
1853 return p;
1854 }
1855
1856 hidden int __dl_invalid_handle(void *h)
1857 {
1858 struct dso *p;
1859 for (p=head; p; p=p->next) if (h==p) return 0;
1860 error("Invalid library handle %p", (void *)h);
1861 return 1;
1862 }
1863
1864 static void *addr2dso(size_t a)
1865 {
1866 struct dso *p;
1867 size_t i;
1868 if (DL_FDPIC) for (p=head; p; p=p->next) {
1869 i = count_syms(p);
1870 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1871 return p;
1872 }
1873 for (p=head; p; p=p->next) {
1874 if (DL_FDPIC && p->loadmap) {
1875 for (i=0; i<p->loadmap->nsegs; i++) {
1876 if (a-p->loadmap->segs[i].p_vaddr
1877 < p->loadmap->segs[i].p_memsz)
1878 return p;
1879 }
1880 } else {
1881 Phdr *ph = p->phdr;
1882 size_t phcnt = p->phnum;
1883 size_t entsz = p->phentsize;
1884 size_t base = (size_t)p->base;
1885 for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
1886 if (ph->p_type != PT_LOAD) continue;
1887 if (a-base-ph->p_vaddr < ph->p_memsz)
1888 return p;
1889 }
1890 if (a-(size_t)p->map < p->map_len)
1891 return 0;
1892 }
1893 }
1894 return 0;
1895 }
1896
1897 void *__tls_get_addr(tls_mod_off_t *);
1898
1899 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1900 {
1901 size_t i;
1902 uint32_t h = 0, gh = 0, *ght;
1903 Sym *sym;
1904 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1905 if (p == RTLD_DEFAULT) {
1906 p = head;
1907 } else if (p == RTLD_NEXT) {
1908 p = addr2dso((size_t)ra);
1909 if (!p) p=head;
1910 p = p->next;
1911 }
1912 struct symdef def = find_sym(p, s, 0);
1913 if (!def.sym) goto failed;
1914 if ((def.sym->st_info&0xf) == STT_TLS)
1915 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value});
1916 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1917 return def.dso->funcdescs + (def.sym - def.dso->syms);
1918 return laddr(def.dso, def.sym->st_value);
1919 }
1920 if (__dl_invalid_handle(p))
1921 return 0;
1922 if ((ght = p->ghashtab)) {
1923 gh = gnu_hash(s);
1924 sym = gnu_lookup(gh, ght, p, s);
1925 } else {
1926 h = sysv_hash(s);
1927 sym = sysv_lookup(s, h, p);
1928 }
1929 if (sym && (sym->st_info&0xf) == STT_TLS)
1930 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value});
1931 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1932 return p->funcdescs + (sym - p->syms);
1933 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1934 return laddr(p, sym->st_value);
1935 for (i=0; p->deps[i]; i++) {
1936 if ((ght = p->deps[i]->ghashtab)) {
1937 if (!gh) gh = gnu_hash(s);
1938 sym = gnu_lookup(gh, ght, p->deps[i], s);
1939 } else {
1940 if (!h) h = sysv_hash(s);
1941 sym = sysv_lookup(s, h, p->deps[i]);
1942 }
1943 if (sym && (sym->st_info&0xf) == STT_TLS)
1944 return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value});
1945 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1946 return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1947 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1948 return laddr(p->deps[i], sym->st_value);
1949 }
1950 failed:
1951 error("Symbol not found: %s", s);
1952 return 0;
1953 }
1954
1955 int dladdr(const void *addr_arg, Dl_info *info)
1956 {
1957 size_t addr = (size_t)addr_arg;
1958 struct dso *p;
1959 Sym *sym, *bestsym;
1960 uint32_t nsym;
1961 char *strings;
1962 size_t best = 0;
1963 size_t besterr = -1;
1964
1965 pthread_rwlock_rdlock(&lock);
1966 p = addr2dso(addr);
1967 pthread_rwlock_unlock(&lock);
1968
1969 if (!p) return 0;
1970
1971 sym = p->syms;
1972 strings = p->strings;
1973 nsym = count_syms(p);
1974
1975 if (DL_FDPIC) {
1976 size_t idx = (addr-(size_t)p->funcdescs)
1977 / sizeof(*p->funcdescs);
1978 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1979 best = (size_t)(p->funcdescs + idx);
1980 bestsym = sym + idx;
1981 besterr = 0;
1982 }
1983 }
1984
1985 if (!best) for (; nsym; nsym--, sym++) {
1986 if (sym->st_value
1987 && (1<<(sym->st_info&0xf) & OK_TYPES)
1988 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1989 size_t symaddr = (size_t)laddr(p, sym->st_value);
1990 if (symaddr > addr || symaddr <= best)
1991 continue;
1992 best = symaddr;
1993 bestsym = sym;
1994 besterr = addr - symaddr;
1995 if (addr == symaddr)
1996 break;
1997 }
1998 }
1999
2000 if (bestsym && besterr > bestsym->st_size-1) {
2001 best = 0;
2002 bestsym = 0;
2003 }
2004
2005 info->dli_fname = p->name;
2006 info->dli_fbase = p->map;
2007
2008 if (!best) {
2009 info->dli_sname = 0;
2010 info->dli_saddr = 0;
2011 return 1;
2012 }
2013
2014 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2015 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2016 info->dli_sname = strings + bestsym->st_name;
2017 info->dli_saddr = (void *)best;
2018
2019 return 1;
2020 }
2021
2022 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2023 {
2024 void *res;
2025 pthread_rwlock_rdlock(&lock);
2026 res = do_dlsym(p, s, ra);
2027 pthread_rwlock_unlock(&lock);
2028 return res;
2029 }
2030
2031 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2032 {
2033 struct dso *current;
2034 struct dl_phdr_info info;
2035 int ret = 0;
2036 for(current = head; current;) {
2037 info.dlpi_addr = (uintptr_t)current->base;
2038 info.dlpi_name = current->name;
2039 info.dlpi_phdr = current->phdr;
2040 info.dlpi_phnum = current->phnum;
2041 info.dlpi_adds = gencnt;
2042 info.dlpi_subs = 0;
2043 info.dlpi_tls_modid = current->tls_id;
2044 info.dlpi_tls_data = current->tls.image;
2045
2046 ret = (callback)(&info, sizeof (info), data);
2047
2048 if (ret != 0) break;
2049
2050 pthread_rwlock_rdlock(&lock);
2051 current = current->next;
2052 pthread_rwlock_unlock(&lock);
2053 }
2054 return ret;
2055 }
2056
2057 hidden void __dl_vseterr(const char *, va_list);
2058
2059 static void error(const char *fmt, ...)
2060 {
2061 va_list ap;
2062 va_start(ap, fmt);
2063 if (!runtime) {
2064 vdprintf(2, fmt, ap);
2065 dprintf(2, "\n");
2066 ldso_fail = 1;
2067 va_end(ap);
2068 return;
2069 }
2070 __dl_vseterr(fmt, ap);
2071 va_end(ap);
2072 }
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