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getaddrinfo: add EAI_NODATA error code to distinguish NODATA vs NxDomain
[musl.git] / ldso / dynlink.c
blob03f5fd59b373bfa0b8a40ca9c277117bcd4b5b3b
1 #define _GNU_SOURCE
2 #define SYSCALL_NO_TLS 1
3 #include <stdlib.h>
4 #include <stdarg.h>
5 #include <stddef.h>
6 #include <string.h>
7 #include <unistd.h>
8 #include <stdint.h>
9 #include <elf.h>
10 #include <sys/mman.h>
11 #include <limits.h>
12 #include <fcntl.h>
13 #include <sys/stat.h>
14 #include <errno.h>
15 #include <link.h>
16 #include <setjmp.h>
17 #include <pthread.h>
18 #include <ctype.h>
19 #include <dlfcn.h>
20 #include <semaphore.h>
21 #include <sys/membarrier.h>
22 #include "pthread_impl.h"
23 #include "fork_impl.h"
24 #include "libc.h"
25 #include "dynlink.h"
26
27 #define malloc __libc_malloc
28 #define calloc __libc_calloc
29 #define realloc __libc_realloc
30 #define free __libc_free
31
32 static void error_impl(const char *, ...);
33 static void error_noop(const char *, ...);
34 static void (*error)(const char *, ...) = error_noop;
35
36 #define MAXP2(a,b) (-(-(a)&-(b)))
37 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
38
39 #define container_of(p,t,m) ((t*)((char *)(p)-offsetof(t,m)))
40 #define countof(a) ((sizeof (a))/(sizeof (a)[0]))
41
42 struct debug {
43 int ver;
44 void *head;
45 void (*bp)(void);
46 int state;
47 void *base;
48 };
49
50 struct td_index {
51 size_t args[2];
52 struct td_index *next;
53 };
54
55 struct dso {
56 #if DL_FDPIC
57 struct fdpic_loadmap *loadmap;
58 #else
59 unsigned char *base;
60 #endif
61 char *name;
62 size_t *dynv;
63 struct dso *next, *prev;
64
65 Phdr *phdr;
66 int phnum;
67 size_t phentsize;
68 Sym *syms;
69 Elf_Symndx *hashtab;
70 uint32_t *ghashtab;
71 int16_t *versym;
72 char *strings;
73 struct dso *syms_next, *lazy_next;
74 size_t *lazy, lazy_cnt;
75 unsigned char *map;
76 size_t map_len;
77 dev_t dev;
78 ino_t ino;
79 char relocated;
80 char constructed;
81 char kernel_mapped;
82 char mark;
83 char bfs_built;
84 char runtime_loaded;
85 struct dso **deps, *needed_by;
86 size_t ndeps_direct;
87 size_t next_dep;
88 pthread_t ctor_visitor;
89 char *rpath_orig, *rpath;
90 struct tls_module tls;
91 size_t tls_id;
92 size_t relro_start, relro_end;
93 uintptr_t *new_dtv;
94 unsigned char *new_tls;
95 struct td_index *td_index;
96 struct dso *fini_next;
97 char *shortname;
98 #if DL_FDPIC
99 unsigned char *base;
100 #else
101 struct fdpic_loadmap *loadmap;
102 #endif
103 struct funcdesc {
104 void *addr;
105 size_t *got;
106 } *funcdescs;
107 size_t *got;
108 char buf[];
109 };
110
111 struct symdef {
112 Sym *sym;
113 struct dso *dso;
114 };
115
116 typedef void (*stage3_func)(size_t *, size_t *);
117
118 static struct builtin_tls {
119 char c;
120 struct pthread pt;
121 void *space[16];
122 } builtin_tls[1];
123 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
124
125 #define ADDEND_LIMIT 4096
126 static size_t *saved_addends, *apply_addends_to;
127
128 static struct dso ldso;
129 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
130 static char *env_path, *sys_path;
131 static unsigned long long gencnt;
132 static int runtime;
133 static int ldd_mode;
134 static int ldso_fail;
135 static int noload;
136 static int shutting_down;
137 static jmp_buf *rtld_fail;
138 static pthread_rwlock_t lock;
139 static struct debug debug;
140 static struct tls_module *tls_tail;
141 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
142 static size_t static_tls_cnt;
143 static pthread_mutex_t init_fini_lock;
144 static pthread_cond_t ctor_cond;
145 static struct dso *builtin_deps[2];
146 static struct dso *const no_deps[1];
147 static struct dso *builtin_ctor_queue[4];
148 static struct dso **main_ctor_queue;
149 static struct fdpic_loadmap *app_loadmap;
150 static struct fdpic_dummy_loadmap app_dummy_loadmap;
151
152 struct debug *_dl_debug_addr = &debug;
153
154 extern hidden int __malloc_replaced;
155
156 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
157
158 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
159
160 weak_alias(__init_array_start, __init_array_end);
161 weak_alias(__fini_array_start, __fini_array_end);
162
163 static int dl_strcmp(const char *l, const char *r)
164 {
165 for (; *l==*r && *l; l++, r++);
166 return *(unsigned char *)l - *(unsigned char *)r;
167 }
168 #define strcmp(l,r) dl_strcmp(l,r)
169
170 /* Compute load address for a virtual address in a given dso. */
171 #if DL_FDPIC
172 static void *laddr(const struct dso *p, size_t v)
173 {
174 size_t j=0;
175 if (!p->loadmap) return p->base + v;
176 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
177 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
178 }
179 static void *laddr_pg(const struct dso *p, size_t v)
180 {
181 size_t j=0;
182 size_t pgsz = PAGE_SIZE;
183 if (!p->loadmap) return p->base + v;
184 for (j=0; ; j++) {
185 size_t a = p->loadmap->segs[j].p_vaddr;
186 size_t b = a + p->loadmap->segs[j].p_memsz;
187 a &= -pgsz;
188 b += pgsz-1;
189 b &= -pgsz;
190 if (v-a<b-a) break;
191 }
192 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
193 }
194 static void (*fdbarrier(void *p))()
195 {
196 void (*fd)();
197 __asm__("" : "=r"(fd) : "0"(p));
198 return fd;
199 }
200 #define fpaddr(p, v) fdbarrier((&(struct funcdesc){ \
201 laddr(p, v), (p)->got }))
202 #else
203 #define laddr(p, v) (void *)((p)->base + (v))
204 #define laddr_pg(p, v) laddr(p, v)
205 #define fpaddr(p, v) ((void (*)())laddr(p, v))
206 #endif
207
208 static void decode_vec(size_t *v, size_t *a, size_t cnt)
209 {
210 size_t i;
211 for (i=0; i<cnt; i++) a[i] = 0;
212 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
213 if (v[0] < 8*sizeof(long))
214 a[0] |= 1UL<<v[0];
215 a[v[0]] = v[1];
216 }
217 }
218
219 static int search_vec(size_t *v, size_t *r, size_t key)
220 {
221 for (; v[0]!=key; v+=2)
222 if (!v[0]) return 0;
223 *r = v[1];
224 return 1;
225 }
226
227 static uint32_t sysv_hash(const char *s0)
228 {
229 const unsigned char *s = (void *)s0;
230 uint_fast32_t h = 0;
231 while (*s) {
232 h = 16*h + *s++;
233 h ^= h>>24 & 0xf0;
234 }
235 return h & 0xfffffff;
236 }
237
238 static uint32_t gnu_hash(const char *s0)
239 {
240 const unsigned char *s = (void *)s0;
241 uint_fast32_t h = 5381;
242 for (; *s; s++)
243 h += h*32 + *s;
244 return h;
245 }
246
247 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
248 {
249 size_t i;
250 Sym *syms = dso->syms;
251 Elf_Symndx *hashtab = dso->hashtab;
252 char *strings = dso->strings;
253 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
254 if ((!dso->versym || dso->versym[i] >= 0)
255 && (!strcmp(s, strings+syms[i].st_name)))
256 return syms+i;
257 }
258 return 0;
259 }
260
261 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
262 {
263 uint32_t nbuckets = hashtab[0];
264 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
265 uint32_t i = buckets[h1 % nbuckets];
266
267 if (!i) return 0;
268
269 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
270
271 for (h1 |= 1; ; i++) {
272 uint32_t h2 = *hashval++;
273 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
274 && !strcmp(s, dso->strings + dso->syms[i].st_name))
275 return dso->syms+i;
276 if (h2 & 1) break;
277 }
278
279 return 0;
280 }
281
282 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
283 {
284 const size_t *bloomwords = (const void *)(hashtab+4);
285 size_t f = bloomwords[fofs & (hashtab[2]-1)];
286 if (!(f & fmask)) return 0;
287
288 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
289 if (!(f & 1)) return 0;
290
291 return gnu_lookup(h1, hashtab, dso, s);
292 }
293
294 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
295 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
296
297 #ifndef ARCH_SYM_REJECT_UND
298 #define ARCH_SYM_REJECT_UND(s) 0
299 #endif
300
301 #if defined(__GNUC__)
302 __attribute__((always_inline))
303 #endif
304 static inline struct symdef find_sym2(struct dso *dso, const char *s, int need_def, int use_deps)
305 {
306 uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
307 size_t ghm = 1ul << gh % (8*sizeof(size_t));
308 struct symdef def = {0};
309 struct dso **deps = use_deps ? dso->deps : 0;
310 for (; dso; dso=use_deps ? *deps++ : dso->syms_next) {
311 Sym *sym;
312 if ((ght = dso->ghashtab)) {
313 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
314 } else {
315 if (!h) h = sysv_hash(s);
316 sym = sysv_lookup(s, h, dso);
317 }
318 if (!sym) continue;
319 if (!sym->st_shndx)
320 if (need_def || (sym->st_info&0xf) == STT_TLS
321 || ARCH_SYM_REJECT_UND(sym))
322 continue;
323 if (!sym->st_value)
324 if ((sym->st_info&0xf) != STT_TLS)
325 continue;
326 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
327 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
328 def.sym = sym;
329 def.dso = dso;
330 break;
331 }
332 return def;
333 }
334
335 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
336 {
337 return find_sym2(dso, s, need_def, 0);
338 }
339
340 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
341 {
342 unsigned char *base = dso->base;
343 Sym *syms = dso->syms;
344 char *strings = dso->strings;
345 Sym *sym;
346 const char *name;
347 void *ctx;
348 int type;
349 int sym_index;
350 struct symdef def;
351 size_t *reloc_addr;
352 size_t sym_val;
353 size_t tls_val;
354 size_t addend;
355 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
356
357 if (dso == &ldso) {
358 /* Only ldso's REL table needs addend saving/reuse. */
359 if (rel == apply_addends_to)
360 reuse_addends = 1;
361 skip_relative = 1;
362 }
363
364 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
365 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
366 type = R_TYPE(rel[1]);
367 if (type == REL_NONE) continue;
368 reloc_addr = laddr(dso, rel[0]);
369
370 if (stride > 2) {
371 addend = rel[2];
372 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
373 addend = 0;
374 } else if (reuse_addends) {
375 /* Save original addend in stage 2 where the dso
376 * chain consists of just ldso; otherwise read back
377 * saved addend since the inline one was clobbered. */
378 if (head==&ldso)
379 saved_addends[save_slot] = *reloc_addr;
380 addend = saved_addends[save_slot++];
381 } else {
382 addend = *reloc_addr;
383 }
384
385 sym_index = R_SYM(rel[1]);
386 if (sym_index) {
387 sym = syms + sym_index;
388 name = strings + sym->st_name;
389 ctx = type==REL_COPY ? head->syms_next : head;
390 def = (sym->st_info>>4) == STB_LOCAL
391 ? (struct symdef){ .dso = dso, .sym = sym }
392 : find_sym(ctx, name, type==REL_PLT);
393 if (!def.sym && (sym->st_shndx != SHN_UNDEF
394 || sym->st_info>>4 != STB_WEAK)) {
395 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
396 dso->lazy[3*dso->lazy_cnt+0] = rel[0];
397 dso->lazy[3*dso->lazy_cnt+1] = rel[1];
398 dso->lazy[3*dso->lazy_cnt+2] = addend;
399 dso->lazy_cnt++;
400 continue;
401 }
402 error("Error relocating %s: %s: symbol not found",
403 dso->name, name);
404 if (runtime) longjmp(*rtld_fail, 1);
405 continue;
406 }
407 } else {
408 sym = 0;
409 def.sym = 0;
410 def.dso = dso;
411 }
412
413 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
414 tls_val = def.sym ? def.sym->st_value : 0;
415
416 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
417 && def.dso->tls_id > static_tls_cnt) {
418 error("Error relocating %s: %s: initial-exec TLS "
419 "resolves to dynamic definition in %s",
420 dso->name, name, def.dso->name);
421 longjmp(*rtld_fail, 1);
422 }
423
424 switch(type) {
425 case REL_OFFSET:
426 addend -= (size_t)reloc_addr;
427 case REL_SYMBOLIC:
428 case REL_GOT:
429 case REL_PLT:
430 *reloc_addr = sym_val + addend;
431 break;
432 case REL_USYMBOLIC:
433 memcpy(reloc_addr, &(size_t){sym_val + addend}, sizeof(size_t));
434 break;
435 case REL_RELATIVE:
436 *reloc_addr = (size_t)base + addend;
437 break;
438 case REL_SYM_OR_REL:
439 if (sym) *reloc_addr = sym_val + addend;
440 else *reloc_addr = (size_t)base + addend;
441 break;
442 case REL_COPY:
443 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
444 break;
445 case REL_OFFSET32:
446 *(uint32_t *)reloc_addr = sym_val + addend
447 - (size_t)reloc_addr;
448 break;
449 case REL_FUNCDESC:
450 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
451 + (def.sym - def.dso->syms)) : 0;
452 break;
453 case REL_FUNCDESC_VAL:
454 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
455 else *reloc_addr = sym_val;
456 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
457 break;
458 case REL_DTPMOD:
459 *reloc_addr = def.dso->tls_id;
460 break;
461 case REL_DTPOFF:
462 *reloc_addr = tls_val + addend - DTP_OFFSET;
463 break;
464 #ifdef TLS_ABOVE_TP
465 case REL_TPOFF:
466 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
467 break;
468 #else
469 case REL_TPOFF:
470 *reloc_addr = tls_val - def.dso->tls.offset + addend;
471 break;
472 case REL_TPOFF_NEG:
473 *reloc_addr = def.dso->tls.offset - tls_val + addend;
474 break;
475 #endif
476 case REL_TLSDESC:
477 if (stride<3) addend = reloc_addr[1];
478 if (def.dso->tls_id > static_tls_cnt) {
479 struct td_index *new = malloc(sizeof *new);
480 if (!new) {
481 error(
482 "Error relocating %s: cannot allocate TLSDESC for %s",
483 dso->name, sym ? name : "(local)" );
484 longjmp(*rtld_fail, 1);
485 }
486 new->next = dso->td_index;
487 dso->td_index = new;
488 new->args[0] = def.dso->tls_id;
489 new->args[1] = tls_val + addend - DTP_OFFSET;
490 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
491 reloc_addr[1] = (size_t)new;
492 } else {
493 reloc_addr[0] = (size_t)__tlsdesc_static;
494 #ifdef TLS_ABOVE_TP
495 reloc_addr[1] = tls_val + def.dso->tls.offset
496 + TPOFF_K + addend;
497 #else
498 reloc_addr[1] = tls_val - def.dso->tls.offset
499 + addend;
500 #endif
501 }
502 #ifdef TLSDESC_BACKWARDS
503 /* Some archs (32-bit ARM at least) invert the order of
504 * the descriptor members. Fix them up here. */
505 size_t tmp = reloc_addr[0];
506 reloc_addr[0] = reloc_addr[1];
507 reloc_addr[1] = tmp;
508 #endif
509 break;
510 default:
511 error("Error relocating %s: unsupported relocation type %d",
512 dso->name, type);
513 if (runtime) longjmp(*rtld_fail, 1);
514 continue;
515 }
516 }
517 }
518
519 static void do_relr_relocs(struct dso *dso, size_t *relr, size_t relr_size)
520 {
521 unsigned char *base = dso->base;
522 size_t *reloc_addr;
523 for (; relr_size; relr++, relr_size-=sizeof(size_t))
524 if ((relr[0]&1) == 0) {
525 reloc_addr = laddr(dso, relr[0]);
526 *reloc_addr++ += (size_t)base;
527 } else {
528 int i = 0;
529 for (size_t bitmap=relr[0]; (bitmap>>=1); i++)
530 if (bitmap&1)
531 reloc_addr[i] += (size_t)base;
532 reloc_addr += 8*sizeof(size_t)-1;
533 }
534 }
535
536 static void redo_lazy_relocs()
537 {
538 struct dso *p = lazy_head, *next;
539 lazy_head = 0;
540 for (; p; p=next) {
541 next = p->lazy_next;
542 size_t size = p->lazy_cnt*3*sizeof(size_t);
543 p->lazy_cnt = 0;
544 do_relocs(p, p->lazy, size, 3);
545 if (p->lazy_cnt) {
546 p->lazy_next = lazy_head;
547 lazy_head = p;
548 } else {
549 free(p->lazy);
550 p->lazy = 0;
551 p->lazy_next = 0;
552 }
553 }
554 }
555
556 /* A huge hack: to make up for the wastefulness of shared libraries
557 * needing at least a page of dirty memory even if they have no global
558 * data, we reclaim the gaps at the beginning and end of writable maps
559 * and "donate" them to the heap. */
560
561 static void reclaim(struct dso *dso, size_t start, size_t end)
562 {
563 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
564 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
565 if (start >= end) return;
566 char *base = laddr_pg(dso, start);
567 __malloc_donate(base, base+(end-start));
568 }
569
570 static void reclaim_gaps(struct dso *dso)
571 {
572 Phdr *ph = dso->phdr;
573 size_t phcnt = dso->phnum;
574
575 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
576 if (ph->p_type!=PT_LOAD) continue;
577 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
578 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
579 reclaim(dso, ph->p_vaddr+ph->p_memsz,
580 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
581 }
582 }
583
584 static ssize_t read_loop(int fd, void *p, size_t n)
585 {
586 for (size_t i=0; i<n; ) {
587 ssize_t l = read(fd, (char *)p+i, n-i);
588 if (l<0) {
589 if (errno==EINTR) continue;
590 else return -1;
591 }
592 if (l==0) return i;
593 i += l;
594 }
595 return n;
596 }
597
598 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
599 {
600 static int no_map_fixed;
601 char *q;
602 if (!n) return p;
603 if (!no_map_fixed) {
604 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
605 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
606 return q;
607 no_map_fixed = 1;
608 }
609 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
610 if (flags & MAP_ANONYMOUS) {
611 memset(p, 0, n);
612 return p;
613 }
614 ssize_t r;
615 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
616 for (q=p; n; q+=r, off+=r, n-=r) {
617 r = read(fd, q, n);
618 if (r < 0 && errno != EINTR) return MAP_FAILED;
619 if (!r) {
620 memset(q, 0, n);
621 break;
622 }
623 }
624 return p;
625 }
626
627 static void unmap_library(struct dso *dso)
628 {
629 if (dso->loadmap) {
630 size_t i;
631 for (i=0; i<dso->loadmap->nsegs; i++) {
632 if (!dso->loadmap->segs[i].p_memsz)
633 continue;
634 munmap((void *)dso->loadmap->segs[i].addr,
635 dso->loadmap->segs[i].p_memsz);
636 }
637 free(dso->loadmap);
638 } else if (dso->map && dso->map_len) {
639 munmap(dso->map, dso->map_len);
640 }
641 }
642
643 static void *map_library(int fd, struct dso *dso)
644 {
645 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
646 void *allocated_buf=0;
647 size_t phsize;
648 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
649 size_t this_min, this_max;
650 size_t nsegs = 0;
651 off_t off_start;
652 Ehdr *eh;
653 Phdr *ph, *ph0;
654 unsigned prot;
655 unsigned char *map=MAP_FAILED, *base;
656 size_t dyn=0;
657 size_t tls_image=0;
658 size_t i;
659
660 ssize_t l = read(fd, buf, sizeof buf);
661 eh = buf;
662 if (l<0) return 0;
663 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
664 goto noexec;
665 phsize = eh->e_phentsize * eh->e_phnum;
666 if (phsize > sizeof buf - sizeof *eh) {
667 allocated_buf = malloc(phsize);
668 if (!allocated_buf) return 0;
669 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
670 if (l < 0) goto error;
671 if (l != phsize) goto noexec;
672 ph = ph0 = allocated_buf;
673 } else if (eh->e_phoff + phsize > l) {
674 l = pread(fd, buf+1, phsize, eh->e_phoff);
675 if (l < 0) goto error;
676 if (l != phsize) goto noexec;
677 ph = ph0 = (void *)(buf + 1);
678 } else {
679 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
680 }
681 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
682 if (ph->p_type == PT_DYNAMIC) {
683 dyn = ph->p_vaddr;
684 } else if (ph->p_type == PT_TLS) {
685 tls_image = ph->p_vaddr;
686 dso->tls.align = ph->p_align;
687 dso->tls.len = ph->p_filesz;
688 dso->tls.size = ph->p_memsz;
689 } else if (ph->p_type == PT_GNU_RELRO) {
690 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
691 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
692 } else if (ph->p_type == PT_GNU_STACK) {
693 if (!runtime && ph->p_memsz > __default_stacksize) {
694 __default_stacksize =
695 ph->p_memsz < DEFAULT_STACK_MAX ?
696 ph->p_memsz : DEFAULT_STACK_MAX;
697 }
698 }
699 if (ph->p_type != PT_LOAD) continue;
700 nsegs++;
701 if (ph->p_vaddr < addr_min) {
702 addr_min = ph->p_vaddr;
703 off_start = ph->p_offset;
704 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
705 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
706 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
707 }
708 if (ph->p_vaddr+ph->p_memsz > addr_max) {
709 addr_max = ph->p_vaddr+ph->p_memsz;
710 }
711 }
712 if (!dyn) goto noexec;
713 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
714 dso->loadmap = calloc(1, sizeof *dso->loadmap
715 + nsegs * sizeof *dso->loadmap->segs);
716 if (!dso->loadmap) goto error;
717 dso->loadmap->nsegs = nsegs;
718 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
719 if (ph->p_type != PT_LOAD) continue;
720 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
721 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
722 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
723 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
724 prot, MAP_PRIVATE,
725 fd, ph->p_offset & -PAGE_SIZE);
726 if (map == MAP_FAILED) {
727 unmap_library(dso);
728 goto error;
729 }
730 dso->loadmap->segs[i].addr = (size_t)map +
731 (ph->p_vaddr & PAGE_SIZE-1);
732 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
733 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
734 i++;
735 if (prot & PROT_WRITE) {
736 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
737 + ph->p_filesz;
738 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
739 size_t pgend = brk + ph->p_memsz - ph->p_filesz
740 + PAGE_SIZE-1 & -PAGE_SIZE;
741 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
742 pgend-pgbrk, prot,
743 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
744 -1, off_start) == MAP_FAILED)
745 goto error;
746 memset(map + brk, 0, pgbrk-brk);
747 }
748 }
749 map = (void *)dso->loadmap->segs[0].addr;
750 map_len = 0;
751 goto done_mapping;
752 }
753 addr_max += PAGE_SIZE-1;
754 addr_max &= -PAGE_SIZE;
755 addr_min &= -PAGE_SIZE;
756 off_start &= -PAGE_SIZE;
757 map_len = addr_max - addr_min + off_start;
758 /* The first time, we map too much, possibly even more than
759 * the length of the file. This is okay because we will not
760 * use the invalid part; we just need to reserve the right
761 * amount of virtual address space to map over later. */
762 map = DL_NOMMU_SUPPORT
763 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
764 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
765 : mmap((void *)addr_min, map_len, prot,
766 MAP_PRIVATE, fd, off_start);
767 if (map==MAP_FAILED) goto error;
768 dso->map = map;
769 dso->map_len = map_len;
770 /* If the loaded file is not relocatable and the requested address is
771 * not available, then the load operation must fail. */
772 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
773 errno = EBUSY;
774 goto error;
775 }
776 base = map - addr_min;
777 dso->phdr = 0;
778 dso->phnum = 0;
779 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
780 if (ph->p_type != PT_LOAD) continue;
781 /* Check if the programs headers are in this load segment, and
782 * if so, record the address for use by dl_iterate_phdr. */
783 if (!dso->phdr && eh->e_phoff >= ph->p_offset
784 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
785 dso->phdr = (void *)(base + ph->p_vaddr
786 + (eh->e_phoff-ph->p_offset));
787 dso->phnum = eh->e_phnum;
788 dso->phentsize = eh->e_phentsize;
789 }
790 this_min = ph->p_vaddr & -PAGE_SIZE;
791 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
792 off_start = ph->p_offset & -PAGE_SIZE;
793 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
794 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
795 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
796 /* Reuse the existing mapping for the lowest-address LOAD */
797 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
798 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
799 goto error;
800 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
801 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
802 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
803 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
804 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)
805 goto error;
806 }
807 }
808 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
809 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
810 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
811 && errno != ENOSYS)
812 goto error;
813 break;
814 }
815 done_mapping:
816 dso->base = base;
817 dso->dynv = laddr(dso, dyn);
818 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
819 free(allocated_buf);
820 return map;
821 noexec:
822 errno = ENOEXEC;
823 error:
824 if (map!=MAP_FAILED) unmap_library(dso);
825 free(allocated_buf);
826 return 0;
827 }
828
829 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
830 {
831 size_t l;
832 int fd;
833 for (;;) {
834 s += strspn(s, ":\n");
835 l = strcspn(s, ":\n");
836 if (l-1 >= INT_MAX) return -1;
837 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
838 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
839 switch (errno) {
840 case ENOENT:
841 case ENOTDIR:
842 case EACCES:
843 case ENAMETOOLONG:
844 break;
845 default:
846 /* Any negative value but -1 will inhibit
847 * futher path search. */
848 return -2;
849 }
850 }
851 s += l;
852 }
853 }
854
855 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
856 {
857 size_t n, l;
858 const char *s, *t, *origin;
859 char *d;
860 if (p->rpath || !p->rpath_orig) return 0;
861 if (!strchr(p->rpath_orig, '$')) {
862 p->rpath = p->rpath_orig;
863 return 0;
864 }
865 n = 0;
866 s = p->rpath_orig;
867 while ((t=strchr(s, '$'))) {
868 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
869 return 0;
870 s = t+1;
871 n++;
872 }
873 if (n > SSIZE_MAX/PATH_MAX) return 0;
874
875 if (p->kernel_mapped) {
876 /* $ORIGIN searches cannot be performed for the main program
877 * when it is suid/sgid/AT_SECURE. This is because the
878 * pathname is under the control of the caller of execve.
879 * For libraries, however, $ORIGIN can be processed safely
880 * since the library's pathname came from a trusted source
881 * (either system paths or a call to dlopen). */
882 if (libc.secure)
883 return 0;
884 l = readlink("/proc/self/exe", buf, buf_size);
885 if (l == -1) switch (errno) {
886 case ENOENT:
887 case ENOTDIR:
888 case EACCES:
889 return 0;
890 default:
891 return -1;
892 }
893 if (l >= buf_size)
894 return 0;
895 buf[l] = 0;
896 origin = buf;
897 } else {
898 origin = p->name;
899 }
900 t = strrchr(origin, '/');
901 if (t) {
902 l = t-origin;
903 } else {
904 /* Normally p->name will always be an absolute or relative
905 * pathname containing at least one '/' character, but in the
906 * case where ldso was invoked as a command to execute a
907 * program in the working directory, app.name may not. Fix. */
908 origin = ".";
909 l = 1;
910 }
911 /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
912 if (libc.secure && *origin != '/')
913 return 0;
914 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
915 if (!p->rpath) return -1;
916
917 d = p->rpath;
918 s = p->rpath_orig;
919 while ((t=strchr(s, '$'))) {
920 memcpy(d, s, t-s);
921 d += t-s;
922 memcpy(d, origin, l);
923 d += l;
924 /* It was determined previously that the '$' is followed
925 * either by "ORIGIN" or "{ORIGIN}". */
926 s = t + 7 + 2*(t[1]=='{');
927 }
928 strcpy(d, s);
929 return 0;
930 }
931
932 static void decode_dyn(struct dso *p)
933 {
934 size_t dyn[DYN_CNT];
935 decode_vec(p->dynv, dyn, DYN_CNT);
936 p->syms = laddr(p, dyn[DT_SYMTAB]);
937 p->strings = laddr(p, dyn[DT_STRTAB]);
938 if (dyn[0]&(1<<DT_HASH))
939 p->hashtab = laddr(p, dyn[DT_HASH]);
940 if (dyn[0]&(1<<DT_RPATH))
941 p->rpath_orig = p->strings + dyn[DT_RPATH];
942 if (dyn[0]&(1<<DT_RUNPATH))
943 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
944 if (dyn[0]&(1<<DT_PLTGOT))
945 p->got = laddr(p, dyn[DT_PLTGOT]);
946 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
947 p->ghashtab = laddr(p, *dyn);
948 if (search_vec(p->dynv, dyn, DT_VERSYM))
949 p->versym = laddr(p, *dyn);
950 }
951
952 static size_t count_syms(struct dso *p)
953 {
954 if (p->hashtab) return p->hashtab[1];
955
956 size_t nsym, i;
957 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
958 uint32_t *hashval;
959 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
960 if (buckets[i] > nsym)
961 nsym = buckets[i];
962 }
963 if (nsym) {
964 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
965 do nsym++;
966 while (!(*hashval++ & 1));
967 }
968 return nsym;
969 }
970
971 static void *dl_mmap(size_t n)
972 {
973 void *p;
974 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
975 #ifdef SYS_mmap2
976 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
977 #else
978 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
979 #endif
980 return (unsigned long)p > -4096UL ? 0 : p;
981 }
982
983 static void makefuncdescs(struct dso *p)
984 {
985 static int self_done;
986 size_t nsym = count_syms(p);
987 size_t i, size = nsym * sizeof(*p->funcdescs);
988
989 if (!self_done) {
990 p->funcdescs = dl_mmap(size);
991 self_done = 1;
992 } else {
993 p->funcdescs = malloc(size);
994 }
995 if (!p->funcdescs) {
996 if (!runtime) a_crash();
997 error("Error allocating function descriptors for %s", p->name);
998 longjmp(*rtld_fail, 1);
999 }
1000 for (i=0; i<nsym; i++) {
1001 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
1002 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
1003 p->funcdescs[i].got = p->got;
1004 } else {
1005 p->funcdescs[i].addr = 0;
1006 p->funcdescs[i].got = 0;
1007 }
1008 }
1009 }
1010
1011 static struct dso *load_library(const char *name, struct dso *needed_by)
1012 {
1013 char buf[2*NAME_MAX+2];
1014 const char *pathname;
1015 unsigned char *map;
1016 struct dso *p, temp_dso = {0};
1017 int fd;
1018 struct stat st;
1019 size_t alloc_size;
1020 int n_th = 0;
1021 int is_self = 0;
1022
1023 if (!*name) {
1024 errno = EINVAL;
1025 return 0;
1026 }
1027
1028 /* Catch and block attempts to reload the implementation itself */
1029 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
1030 static const char reserved[] =
1031 "c.pthread.rt.m.dl.util.xnet.";
1032 const char *rp, *next;
1033 for (rp=reserved; *rp; rp=next) {
1034 next = strchr(rp, '.') + 1;
1035 if (strncmp(name+3, rp, next-rp) == 0)
1036 break;
1037 }
1038 if (*rp) {
1039 if (ldd_mode) {
1040 /* Track which names have been resolved
1041 * and only report each one once. */
1042 static unsigned reported;
1043 unsigned mask = 1U<<(rp-reserved);
1044 if (!(reported & mask)) {
1045 reported |= mask;
1046 dprintf(1, "\t%s => %s (%p)\n",
1047 name, ldso.name,
1048 ldso.base);
1049 }
1050 }
1051 is_self = 1;
1052 }
1053 }
1054 if (!strcmp(name, ldso.name)) is_self = 1;
1055 if (is_self) {
1056 if (!ldso.prev) {
1057 tail->next = &ldso;
1058 ldso.prev = tail;
1059 tail = &ldso;
1060 }
1061 return &ldso;
1062 }
1063 if (strchr(name, '/')) {
1064 pathname = name;
1065 fd = open(name, O_RDONLY|O_CLOEXEC);
1066 } else {
1067 /* Search for the name to see if it's already loaded */
1068 for (p=head->next; p; p=p->next) {
1069 if (p->shortname && !strcmp(p->shortname, name)) {
1070 return p;
1071 }
1072 }
1073 if (strlen(name) > NAME_MAX) return 0;
1074 fd = -1;
1075 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
1076 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
1077 if (fixup_rpath(p, buf, sizeof buf) < 0)
1078 fd = -2; /* Inhibit further search. */
1079 if (p->rpath)
1080 fd = path_open(name, p->rpath, buf, sizeof buf);
1081 }
1082 if (fd == -1) {
1083 if (!sys_path) {
1084 char *prefix = 0;
1085 size_t prefix_len;
1086 if (ldso.name[0]=='/') {
1087 char *s, *t, *z;
1088 for (s=t=z=ldso.name; *s; s++)
1089 if (*s=='/') z=t, t=s;
1090 prefix_len = z-ldso.name;
1091 if (prefix_len < PATH_MAX)
1092 prefix = ldso.name;
1093 }
1094 if (!prefix) {
1095 prefix = "";
1096 prefix_len = 0;
1097 }
1098 char etc_ldso_path[prefix_len + 1
1099 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1100 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1101 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1102 (int)prefix_len, prefix);
1103 fd = open(etc_ldso_path, O_RDONLY|O_CLOEXEC);
1104 if (fd>=0) {
1105 size_t n = 0;
1106 if (!fstat(fd, &st)) n = st.st_size;
1107 if ((sys_path = malloc(n+1)))
1108 sys_path[n] = 0;
1109 if (!sys_path || read_loop(fd, sys_path, n)<0) {
1110 free(sys_path);
1111 sys_path = "";
1112 }
1113 close(fd);
1114 } else if (errno != ENOENT) {
1115 sys_path = "";
1116 }
1117 }
1118 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1119 fd = path_open(name, sys_path, buf, sizeof buf);
1120 }
1121 pathname = buf;
1122 }
1123 if (fd < 0) return 0;
1124 if (fstat(fd, &st) < 0) {
1125 close(fd);
1126 return 0;
1127 }
1128 for (p=head->next; p; p=p->next) {
1129 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1130 /* If this library was previously loaded with a
1131 * pathname but a search found the same inode,
1132 * setup its shortname so it can be found by name. */
1133 if (!p->shortname && pathname != name)
1134 p->shortname = strrchr(p->name, '/')+1;
1135 close(fd);
1136 return p;
1137 }
1138 }
1139 map = noload ? 0 : map_library(fd, &temp_dso);
1140 close(fd);
1141 if (!map) return 0;
1142
1143 /* Avoid the danger of getting two versions of libc mapped into the
1144 * same process when an absolute pathname was used. The symbols
1145 * checked are chosen to catch both musl and glibc, and to avoid
1146 * false positives from interposition-hack libraries. */
1147 decode_dyn(&temp_dso);
1148 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1149 find_sym(&temp_dso, "stdin", 1).sym) {
1150 unmap_library(&temp_dso);
1151 return load_library("libc.so", needed_by);
1152 }
1153 /* Past this point, if we haven't reached runtime yet, ldso has
1154 * committed either to use the mapped library or to abort execution.
1155 * Unmapping is not possible, so we can safely reclaim gaps. */
1156 if (!runtime) reclaim_gaps(&temp_dso);
1157
1158 /* Allocate storage for the new DSO. When there is TLS, this
1159 * storage must include a reservation for all pre-existing
1160 * threads to obtain copies of both the new TLS, and an
1161 * extended DTV capable of storing an additional slot for
1162 * the newly-loaded DSO. */
1163 alloc_size = sizeof *p + strlen(pathname) + 1;
1164 if (runtime && temp_dso.tls.image) {
1165 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1166 + sizeof(void *) * (tls_cnt+3);
1167 n_th = libc.threads_minus_1 + 1;
1168 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1169 else alloc_size += n_th * per_th;
1170 }
1171 p = calloc(1, alloc_size);
1172 if (!p) {
1173 unmap_library(&temp_dso);
1174 return 0;
1175 }
1176 memcpy(p, &temp_dso, sizeof temp_dso);
1177 p->dev = st.st_dev;
1178 p->ino = st.st_ino;
1179 p->needed_by = needed_by;
1180 p->name = p->buf;
1181 p->runtime_loaded = runtime;
1182 strcpy(p->name, pathname);
1183 /* Add a shortname only if name arg was not an explicit pathname. */
1184 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1185 if (p->tls.image) {
1186 p->tls_id = ++tls_cnt;
1187 tls_align = MAXP2(tls_align, p->tls.align);
1188 #ifdef TLS_ABOVE_TP
1189 p->tls.offset = tls_offset + ( (p->tls.align-1) &
1190 (-tls_offset + (uintptr_t)p->tls.image) );
1191 tls_offset = p->tls.offset + p->tls.size;
1192 #else
1193 tls_offset += p->tls.size + p->tls.align - 1;
1194 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1195 & (p->tls.align-1);
1196 p->tls.offset = tls_offset;
1197 #endif
1198 p->new_dtv = (void *)(-sizeof(size_t) &
1199 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1200 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1201 if (tls_tail) tls_tail->next = &p->tls;
1202 else libc.tls_head = &p->tls;
1203 tls_tail = &p->tls;
1204 }
1205
1206 tail->next = p;
1207 p->prev = tail;
1208 tail = p;
1209
1210 if (DL_FDPIC) makefuncdescs(p);
1211
1212 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1213
1214 return p;
1215 }
1216
1217 static void load_direct_deps(struct dso *p)
1218 {
1219 size_t i, cnt=0;
1220
1221 if (p->deps) return;
1222 /* For head, all preloads are direct pseudo-dependencies.
1223 * Count and include them now to avoid realloc later. */
1224 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1225 cnt++;
1226 for (i=0; p->dynv[i]; i+=2)
1227 if (p->dynv[i] == DT_NEEDED) cnt++;
1228 /* Use builtin buffer for apps with no external deps, to
1229 * preserve property of no runtime failure paths. */
1230 p->deps = (p==head && cnt<2) ? builtin_deps :
1231 calloc(cnt+1, sizeof *p->deps);
1232 if (!p->deps) {
1233 error("Error loading dependencies for %s", p->name);
1234 if (runtime) longjmp(*rtld_fail, 1);
1235 }
1236 cnt=0;
1237 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1238 p->deps[cnt++] = q;
1239 for (i=0; p->dynv[i]; i+=2) {
1240 if (p->dynv[i] != DT_NEEDED) continue;
1241 struct dso *dep = load_library(p->strings + p->dynv[i+1], p);
1242 if (!dep) {
1243 error("Error loading shared library %s: %m (needed by %s)",
1244 p->strings + p->dynv[i+1], p->name);
1245 if (runtime) longjmp(*rtld_fail, 1);
1246 continue;
1247 }
1248 p->deps[cnt++] = dep;
1249 }
1250 p->deps[cnt] = 0;
1251 p->ndeps_direct = cnt;
1252 }
1253
1254 static void load_deps(struct dso *p)
1255 {
1256 if (p->deps) return;
1257 for (; p; p=p->next)
1258 load_direct_deps(p);
1259 }
1260
1261 static void extend_bfs_deps(struct dso *p)
1262 {
1263 size_t i, j, cnt, ndeps_all;
1264 struct dso **tmp;
1265
1266 /* Can't use realloc if the original p->deps was allocated at
1267 * program entry and malloc has been replaced, or if it's
1268 * the builtin non-allocated trivial main program deps array. */
1269 int no_realloc = (__malloc_replaced && !p->runtime_loaded)
1270 || p->deps == builtin_deps;
1271
1272 if (p->bfs_built) return;
1273 ndeps_all = p->ndeps_direct;
1274
1275 /* Mark existing (direct) deps so they won't be duplicated. */
1276 for (i=0; p->deps[i]; i++)
1277 p->deps[i]->mark = 1;
1278
1279 /* For each dependency already in the list, copy its list of direct
1280 * dependencies to the list, excluding any items already in the
1281 * list. Note that the list this loop iterates over will grow during
1282 * the loop, but since duplicates are excluded, growth is bounded. */
1283 for (i=0; p->deps[i]; i++) {
1284 struct dso *dep = p->deps[i];
1285 for (j=cnt=0; j<dep->ndeps_direct; j++)
1286 if (!dep->deps[j]->mark) cnt++;
1287 tmp = no_realloc ?
1288 malloc(sizeof(*tmp) * (ndeps_all+cnt+1)) :
1289 realloc(p->deps, sizeof(*tmp) * (ndeps_all+cnt+1));
1290 if (!tmp) {
1291 error("Error recording dependencies for %s", p->name);
1292 if (runtime) longjmp(*rtld_fail, 1);
1293 continue;
1294 }
1295 if (no_realloc) {
1296 memcpy(tmp, p->deps, sizeof(*tmp) * (ndeps_all+1));
1297 no_realloc = 0;
1298 }
1299 p->deps = tmp;
1300 for (j=0; j<dep->ndeps_direct; j++) {
1301 if (dep->deps[j]->mark) continue;
1302 dep->deps[j]->mark = 1;
1303 p->deps[ndeps_all++] = dep->deps[j];
1304 }
1305 p->deps[ndeps_all] = 0;
1306 }
1307 p->bfs_built = 1;
1308 for (p=head; p; p=p->next)
1309 p->mark = 0;
1310 }
1311
1312 static void load_preload(char *s)
1313 {
1314 int tmp;
1315 char *z;
1316 for (z=s; *z; s=z) {
1317 for ( ; *s && (isspace(*s) || *s==':'); s++);
1318 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1319 tmp = *z;
1320 *z = 0;
1321 load_library(s, 0);
1322 *z = tmp;
1323 }
1324 }
1325
1326 static void add_syms(struct dso *p)
1327 {
1328 if (!p->syms_next && syms_tail != p) {
1329 syms_tail->syms_next = p;
1330 syms_tail = p;
1331 }
1332 }
1333
1334 static void revert_syms(struct dso *old_tail)
1335 {
1336 struct dso *p, *next;
1337 /* Chop off the tail of the list of dsos that participate in
1338 * the global symbol table, reverting them to RTLD_LOCAL. */
1339 for (p=old_tail; p; p=next) {
1340 next = p->syms_next;
1341 p->syms_next = 0;
1342 }
1343 syms_tail = old_tail;
1344 }
1345
1346 static void do_mips_relocs(struct dso *p, size_t *got)
1347 {
1348 size_t i, j, rel[2];
1349 unsigned char *base = p->base;
1350 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1351 if (p==&ldso) {
1352 got += i;
1353 } else {
1354 while (i--) *got++ += (size_t)base;
1355 }
1356 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1357 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1358 Sym *sym = p->syms + j;
1359 rel[0] = (unsigned char *)got - base;
1360 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1361 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1362 do_relocs(p, rel, sizeof rel, 2);
1363 }
1364 }
1365
1366 static void reloc_all(struct dso *p)
1367 {
1368 size_t dyn[DYN_CNT];
1369 for (; p; p=p->next) {
1370 if (p->relocated) continue;
1371 decode_vec(p->dynv, dyn, DYN_CNT);
1372 if (NEED_MIPS_GOT_RELOCS)
1373 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1374 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1375 2+(dyn[DT_PLTREL]==DT_RELA));
1376 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1377 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1378 if (!DL_FDPIC)
1379 do_relr_relocs(p, laddr(p, dyn[DT_RELR]), dyn[DT_RELRSZ]);
1380
1381 if (head != &ldso && p->relro_start != p->relro_end) {
1382 long ret = __syscall(SYS_mprotect, laddr(p, p->relro_start),
1383 p->relro_end-p->relro_start, PROT_READ);
1384 if (ret != 0 && ret != -ENOSYS) {
1385 error("Error relocating %s: RELRO protection failed: %m",
1386 p->name);
1387 if (runtime) longjmp(*rtld_fail, 1);
1388 }
1389 }
1390
1391 p->relocated = 1;
1392 }
1393 }
1394
1395 static void kernel_mapped_dso(struct dso *p)
1396 {
1397 size_t min_addr = -1, max_addr = 0, cnt;
1398 Phdr *ph = p->phdr;
1399 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1400 if (ph->p_type == PT_DYNAMIC) {
1401 p->dynv = laddr(p, ph->p_vaddr);
1402 } else if (ph->p_type == PT_GNU_RELRO) {
1403 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1404 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1405 } else if (ph->p_type == PT_GNU_STACK) {
1406 if (!runtime && ph->p_memsz > __default_stacksize) {
1407 __default_stacksize =
1408 ph->p_memsz < DEFAULT_STACK_MAX ?
1409 ph->p_memsz : DEFAULT_STACK_MAX;
1410 }
1411 }
1412 if (ph->p_type != PT_LOAD) continue;
1413 if (ph->p_vaddr < min_addr)
1414 min_addr = ph->p_vaddr;
1415 if (ph->p_vaddr+ph->p_memsz > max_addr)
1416 max_addr = ph->p_vaddr+ph->p_memsz;
1417 }
1418 min_addr &= -PAGE_SIZE;
1419 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1420 p->map = p->base + min_addr;
1421 p->map_len = max_addr - min_addr;
1422 p->kernel_mapped = 1;
1423 }
1424
1425 void __libc_exit_fini()
1426 {
1427 struct dso *p;
1428 size_t dyn[DYN_CNT];
1429 pthread_t self = __pthread_self();
1430
1431 /* Take both locks before setting shutting_down, so that
1432 * either lock is sufficient to read its value. The lock
1433 * order matches that in dlopen to avoid deadlock. */
1434 pthread_rwlock_wrlock(&lock);
1435 pthread_mutex_lock(&init_fini_lock);
1436 shutting_down = 1;
1437 pthread_rwlock_unlock(&lock);
1438 for (p=fini_head; p; p=p->fini_next) {
1439 while (p->ctor_visitor && p->ctor_visitor!=self)
1440 pthread_cond_wait(&ctor_cond, &init_fini_lock);
1441 if (!p->constructed) continue;
1442 decode_vec(p->dynv, dyn, DYN_CNT);
1443 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1444 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1445 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1446 while (n--) ((void (*)(void))*--fn)();
1447 }
1448 #ifndef NO_LEGACY_INITFINI
1449 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1450 fpaddr(p, dyn[DT_FINI])();
1451 #endif
1452 }
1453 }
1454
1455 void __ldso_atfork(int who)
1456 {
1457 if (who<0) {
1458 pthread_rwlock_wrlock(&lock);
1459 pthread_mutex_lock(&init_fini_lock);
1460 } else {
1461 pthread_mutex_unlock(&init_fini_lock);
1462 pthread_rwlock_unlock(&lock);
1463 }
1464 }
1465
1466 static struct dso **queue_ctors(struct dso *dso)
1467 {
1468 size_t cnt, qpos, spos, i;
1469 struct dso *p, **queue, **stack;
1470
1471 if (ldd_mode) return 0;
1472
1473 /* Bound on queue size is the total number of indirect deps.
1474 * If a bfs deps list was built, we can use it. Otherwise,
1475 * bound by the total number of DSOs, which is always safe and
1476 * is reasonable we use it (for main app at startup). */
1477 if (dso->bfs_built) {
1478 for (cnt=0; dso->deps[cnt]; cnt++)
1479 dso->deps[cnt]->mark = 0;
1480 cnt++; /* self, not included in deps */
1481 } else {
1482 for (cnt=0, p=head; p; cnt++, p=p->next)
1483 p->mark = 0;
1484 }
1485 cnt++; /* termination slot */
1486 if (dso==head && cnt <= countof(builtin_ctor_queue))
1487 queue = builtin_ctor_queue;
1488 else
1489 queue = calloc(cnt, sizeof *queue);
1490
1491 if (!queue) {
1492 error("Error allocating constructor queue: %m\n");
1493 if (runtime) longjmp(*rtld_fail, 1);
1494 return 0;
1495 }
1496
1497 /* Opposite ends of the allocated buffer serve as an output queue
1498 * and a working stack. Setup initial stack with just the argument
1499 * dso and initial queue empty... */
1500 stack = queue;
1501 qpos = 0;
1502 spos = cnt;
1503 stack[--spos] = dso;
1504 dso->next_dep = 0;
1505 dso->mark = 1;
1506
1507 /* Then perform pseudo-DFS sort, but ignoring circular deps. */
1508 while (spos<cnt) {
1509 p = stack[spos++];
1510 while (p->next_dep < p->ndeps_direct) {
1511 if (p->deps[p->next_dep]->mark) {
1512 p->next_dep++;
1513 } else {
1514 stack[--spos] = p;
1515 p = p->deps[p->next_dep];
1516 p->next_dep = 0;
1517 p->mark = 1;
1518 }
1519 }
1520 queue[qpos++] = p;
1521 }
1522 queue[qpos] = 0;
1523 for (i=0; i<qpos; i++) queue[i]->mark = 0;
1524 for (i=0; i<qpos; i++)
1525 if (queue[i]->ctor_visitor && queue[i]->ctor_visitor->tid < 0) {
1526 error("State of %s is inconsistent due to multithreaded fork\n",
1527 queue[i]->name);
1528 free(queue);
1529 if (runtime) longjmp(*rtld_fail, 1);
1530 }
1531
1532 return queue;
1533 }
1534
1535 static void do_init_fini(struct dso **queue)
1536 {
1537 struct dso *p;
1538 size_t dyn[DYN_CNT], i;
1539 pthread_t self = __pthread_self();
1540
1541 pthread_mutex_lock(&init_fini_lock);
1542 for (i=0; (p=queue[i]); i++) {
1543 while ((p->ctor_visitor && p->ctor_visitor!=self) || shutting_down)
1544 pthread_cond_wait(&ctor_cond, &init_fini_lock);
1545 if (p->ctor_visitor || p->constructed)
1546 continue;
1547 p->ctor_visitor = self;
1548
1549 decode_vec(p->dynv, dyn, DYN_CNT);
1550 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1551 p->fini_next = fini_head;
1552 fini_head = p;
1553 }
1554
1555 pthread_mutex_unlock(&init_fini_lock);
1556
1557 #ifndef NO_LEGACY_INITFINI
1558 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1559 fpaddr(p, dyn[DT_INIT])();
1560 #endif
1561 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1562 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1563 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1564 while (n--) ((void (*)(void))*fn++)();
1565 }
1566
1567 pthread_mutex_lock(&init_fini_lock);
1568 p->ctor_visitor = 0;
1569 p->constructed = 1;
1570 pthread_cond_broadcast(&ctor_cond);
1571 }
1572 pthread_mutex_unlock(&init_fini_lock);
1573 }
1574
1575 void __libc_start_init(void)
1576 {
1577 do_init_fini(main_ctor_queue);
1578 if (!__malloc_replaced && main_ctor_queue != builtin_ctor_queue)
1579 free(main_ctor_queue);
1580 main_ctor_queue = 0;
1581 }
1582
1583 static void dl_debug_state(void)
1584 {
1585 }
1586
1587 weak_alias(dl_debug_state, _dl_debug_state);
1588
1589 void __init_tls(size_t *auxv)
1590 {
1591 }
1592
1593 static void update_tls_size()
1594 {
1595 libc.tls_cnt = tls_cnt;
1596 libc.tls_align = tls_align;
1597 libc.tls_size = ALIGN(
1598 (1+tls_cnt) * sizeof(void *) +
1599 tls_offset +
1600 sizeof(struct pthread) +
1601 tls_align * 2,
1602 tls_align);
1603 }
1604
1605 static void install_new_tls(void)
1606 {
1607 sigset_t set;
1608 pthread_t self = __pthread_self(), td;
1609 struct dso *dtv_provider = container_of(tls_tail, struct dso, tls);
1610 uintptr_t (*newdtv)[tls_cnt+1] = (void *)dtv_provider->new_dtv;
1611 struct dso *p;
1612 size_t i, j;
1613 size_t old_cnt = self->dtv[0];
1614
1615 __block_app_sigs(&set);
1616 __tl_lock();
1617 /* Copy existing dtv contents from all existing threads. */
1618 for (i=0, td=self; !i || td!=self; i++, td=td->next) {
1619 memcpy(newdtv+i, td->dtv,
1620 (old_cnt+1)*sizeof(uintptr_t));
1621 newdtv[i][0] = tls_cnt;
1622 }
1623 /* Install new dtls into the enlarged, uninstalled dtv copies. */
1624 for (p=head; ; p=p->next) {
1625 if (p->tls_id <= old_cnt) continue;
1626 unsigned char *mem = p->new_tls;
1627 for (j=0; j<i; j++) {
1628 unsigned char *new = mem;
1629 new += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1630 & (p->tls.align-1);
1631 memcpy(new, p->tls.image, p->tls.len);
1632 newdtv[j][p->tls_id] =
1633 (uintptr_t)new + DTP_OFFSET;
1634 mem += p->tls.size + p->tls.align;
1635 }
1636 if (p->tls_id == tls_cnt) break;
1637 }
1638
1639 /* Broadcast barrier to ensure contents of new dtv is visible
1640 * if the new dtv pointer is. The __membarrier function has a
1641 * fallback emulation using signals for kernels that lack the
1642 * feature at the syscall level. */
1643
1644 __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED, 0);
1645
1646 /* Install new dtv for each thread. */
1647 for (j=0, td=self; !j || td!=self; j++, td=td->next) {
1648 td->dtv = newdtv[j];
1649 }
1650
1651 __tl_unlock();
1652 __restore_sigs(&set);
1653 }
1654
1655 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1656 * following stage 2 and stage 3 functions via primitive symbolic lookup
1657 * since it does not have access to their addresses to begin with. */
1658
1659 /* Stage 2 of the dynamic linker is called after relative relocations
1660 * have been processed. It can make function calls to static functions
1661 * and access string literals and static data, but cannot use extern
1662 * symbols. Its job is to perform symbolic relocations on the dynamic
1663 * linker itself, but some of the relocations performed may need to be
1664 * replaced later due to copy relocations in the main program. */
1665
1666 hidden void __dls2(unsigned char *base, size_t *sp)
1667 {
1668 size_t *auxv;
1669 for (auxv=sp+1+*sp+1; *auxv; auxv++);
1670 auxv++;
1671 if (DL_FDPIC) {
1672 void *p1 = (void *)sp[-2];
1673 void *p2 = (void *)sp[-1];
1674 if (!p1) {
1675 size_t aux[AUX_CNT];
1676 decode_vec(auxv, aux, AUX_CNT);
1677 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1678 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1679 }
1680 app_loadmap = p2 ? p1 : 0;
1681 ldso.loadmap = p2 ? p2 : p1;
1682 ldso.base = laddr(&ldso, 0);
1683 } else {
1684 ldso.base = base;
1685 }
1686 Ehdr *ehdr = (void *)ldso.base;
1687 ldso.name = ldso.shortname = "libc.so";
1688 ldso.phnum = ehdr->e_phnum;
1689 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1690 ldso.phentsize = ehdr->e_phentsize;
1691 kernel_mapped_dso(&ldso);
1692 decode_dyn(&ldso);
1693
1694 if (DL_FDPIC) makefuncdescs(&ldso);
1695
1696 /* Prepare storage for to save clobbered REL addends so they
1697 * can be reused in stage 3. There should be very few. If
1698 * something goes wrong and there are a huge number, abort
1699 * instead of risking stack overflow. */
1700 size_t dyn[DYN_CNT];
1701 decode_vec(ldso.dynv, dyn, DYN_CNT);
1702 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1703 size_t rel_size = dyn[DT_RELSZ];
1704 size_t symbolic_rel_cnt = 0;
1705 apply_addends_to = rel;
1706 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1707 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1708 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1709 size_t addends[symbolic_rel_cnt+1];
1710 saved_addends = addends;
1711
1712 head = &ldso;
1713 reloc_all(&ldso);
1714
1715 ldso.relocated = 0;
1716
1717 /* Call dynamic linker stage-2b, __dls2b, looking it up
1718 * symbolically as a barrier against moving the address
1719 * load across the above relocation processing. */
1720 struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0);
1721 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp, auxv);
1722 else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp, auxv);
1723 }
1724
1725 /* Stage 2b sets up a valid thread pointer, which requires relocations
1726 * completed in stage 2, and on which stage 3 is permitted to depend.
1727 * This is done as a separate stage, with symbolic lookup as a barrier,
1728 * so that loads of the thread pointer and &errno can be pure/const and
1729 * thereby hoistable. */
1730
1731 void __dls2b(size_t *sp, size_t *auxv)
1732 {
1733 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1734 * use during dynamic linking. If possible it will also serve as the
1735 * thread pointer at runtime. */
1736 search_vec(auxv, &__hwcap, AT_HWCAP);
1737 libc.auxv = auxv;
1738 libc.tls_size = sizeof builtin_tls;
1739 libc.tls_align = tls_align;
1740 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1741 a_crash();
1742 }
1743
1744 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1745 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp, auxv);
1746 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp, auxv);
1747 }
1748
1749 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1750 * fully functional. Its job is to load (if not already loaded) and
1751 * process dependencies and relocations for the main application and
1752 * transfer control to its entry point. */
1753
1754 void __dls3(size_t *sp, size_t *auxv)
1755 {
1756 static struct dso app, vdso;
1757 size_t aux[AUX_CNT];
1758 size_t i;
1759 char *env_preload=0;
1760 char *replace_argv0=0;
1761 size_t vdso_base;
1762 int argc = *sp;
1763 char **argv = (void *)(sp+1);
1764 char **argv_orig = argv;
1765 char **envp = argv+argc+1;
1766
1767 /* Find aux vector just past environ[] and use it to initialize
1768 * global data that may be needed before we can make syscalls. */
1769 __environ = envp;
1770 decode_vec(auxv, aux, AUX_CNT);
1771 search_vec(auxv, &__sysinfo, AT_SYSINFO);
1772 __pthread_self()->sysinfo = __sysinfo;
1773 libc.page_size = aux[AT_PAGESZ];
1774 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1775 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1776
1777 /* Only trust user/env if kernel says we're not suid/sgid */
1778 if (!libc.secure) {
1779 env_path = getenv("LD_LIBRARY_PATH");
1780 env_preload = getenv("LD_PRELOAD");
1781 }
1782
1783 /* Activate error handler function */
1784 error = error_impl;
1785
1786 /* If the main program was already loaded by the kernel,
1787 * AT_PHDR will point to some location other than the dynamic
1788 * linker's program headers. */
1789 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1790 size_t interp_off = 0;
1791 size_t tls_image = 0;
1792 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1793 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1794 app.phnum = aux[AT_PHNUM];
1795 app.phentsize = aux[AT_PHENT];
1796 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1797 if (phdr->p_type == PT_PHDR)
1798 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1799 else if (phdr->p_type == PT_INTERP)
1800 interp_off = (size_t)phdr->p_vaddr;
1801 else if (phdr->p_type == PT_TLS) {
1802 tls_image = phdr->p_vaddr;
1803 app.tls.len = phdr->p_filesz;
1804 app.tls.size = phdr->p_memsz;
1805 app.tls.align = phdr->p_align;
1806 }
1807 }
1808 if (DL_FDPIC) app.loadmap = app_loadmap;
1809 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1810 if (interp_off) ldso.name = laddr(&app, interp_off);
1811 if ((aux[0] & (1UL<<AT_EXECFN))
1812 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1813 app.name = (char *)aux[AT_EXECFN];
1814 else
1815 app.name = argv[0];
1816 kernel_mapped_dso(&app);
1817 } else {
1818 int fd;
1819 char *ldname = argv[0];
1820 size_t l = strlen(ldname);
1821 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1822 argv++;
1823 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1824 char *opt = argv[0]+2;
1825 *argv++ = (void *)-1;
1826 if (!*opt) {
1827 break;
1828 } else if (!memcmp(opt, "list", 5)) {
1829 ldd_mode = 1;
1830 } else if (!memcmp(opt, "library-path", 12)) {
1831 if (opt[12]=='=') env_path = opt+13;
1832 else if (opt[12]) *argv = 0;
1833 else if (*argv) env_path = *argv++;
1834 } else if (!memcmp(opt, "preload", 7)) {
1835 if (opt[7]=='=') env_preload = opt+8;
1836 else if (opt[7]) *argv = 0;
1837 else if (*argv) env_preload = *argv++;
1838 } else if (!memcmp(opt, "argv0", 5)) {
1839 if (opt[5]=='=') replace_argv0 = opt+6;
1840 else if (opt[5]) *argv = 0;
1841 else if (*argv) replace_argv0 = *argv++;
1842 } else {
1843 argv[0] = 0;
1844 }
1845 }
1846 argv[-1] = (void *)(argc - (argv-argv_orig));
1847 if (!argv[0]) {
1848 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1849 "Version %s\n"
1850 "Dynamic Program Loader\n"
1851 "Usage: %s [options] [--] pathname%s\n",
1852 __libc_version, ldname,
1853 ldd_mode ? "" : " [args]");
1854 _exit(1);
1855 }
1856 fd = open(argv[0], O_RDONLY);
1857 if (fd < 0) {
1858 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1859 _exit(1);
1860 }
1861 Ehdr *ehdr = map_library(fd, &app);
1862 if (!ehdr) {
1863 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1864 _exit(1);
1865 }
1866 close(fd);
1867 ldso.name = ldname;
1868 app.name = argv[0];
1869 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1870 /* Find the name that would have been used for the dynamic
1871 * linker had ldd not taken its place. */
1872 if (ldd_mode) {
1873 for (i=0; i<app.phnum; i++) {
1874 if (app.phdr[i].p_type == PT_INTERP)
1875 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1876 }
1877 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1878 }
1879 }
1880 if (app.tls.size) {
1881 libc.tls_head = tls_tail = &app.tls;
1882 app.tls_id = tls_cnt = 1;
1883 #ifdef TLS_ABOVE_TP
1884 app.tls.offset = GAP_ABOVE_TP;
1885 app.tls.offset += (-GAP_ABOVE_TP + (uintptr_t)app.tls.image)
1886 & (app.tls.align-1);
1887 tls_offset = app.tls.offset + app.tls.size;
1888 #else
1889 tls_offset = app.tls.offset = app.tls.size
1890 + ( -((uintptr_t)app.tls.image + app.tls.size)
1891 & (app.tls.align-1) );
1892 #endif
1893 tls_align = MAXP2(tls_align, app.tls.align);
1894 }
1895 decode_dyn(&app);
1896 if (DL_FDPIC) {
1897 makefuncdescs(&app);
1898 if (!app.loadmap) {
1899 app.loadmap = (void *)&app_dummy_loadmap;
1900 app.loadmap->nsegs = 1;
1901 app.loadmap->segs[0].addr = (size_t)app.map;
1902 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1903 - (size_t)app.base;
1904 app.loadmap->segs[0].p_memsz = app.map_len;
1905 }
1906 argv[-3] = (void *)app.loadmap;
1907 }
1908
1909 /* Initial dso chain consists only of the app. */
1910 head = tail = syms_tail = &app;
1911
1912 /* Donate unused parts of app and library mapping to malloc */
1913 reclaim_gaps(&app);
1914 reclaim_gaps(&ldso);
1915
1916 /* Load preload/needed libraries, add symbols to global namespace. */
1917 ldso.deps = (struct dso **)no_deps;
1918 if (env_preload) load_preload(env_preload);
1919 load_deps(&app);
1920 for (struct dso *p=head; p; p=p->next)
1921 add_syms(p);
1922
1923 /* Attach to vdso, if provided by the kernel, last so that it does
1924 * not become part of the global namespace. */
1925 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1926 Ehdr *ehdr = (void *)vdso_base;
1927 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1928 vdso.phnum = ehdr->e_phnum;
1929 vdso.phentsize = ehdr->e_phentsize;
1930 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1931 if (phdr->p_type == PT_DYNAMIC)
1932 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1933 if (phdr->p_type == PT_LOAD)
1934 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1935 }
1936 vdso.name = "";
1937 vdso.shortname = "linux-gate.so.1";
1938 vdso.relocated = 1;
1939 vdso.deps = (struct dso **)no_deps;
1940 decode_dyn(&vdso);
1941 vdso.prev = tail;
1942 tail->next = &vdso;
1943 tail = &vdso;
1944 }
1945
1946 for (i=0; app.dynv[i]; i+=2) {
1947 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1948 app.dynv[i+1] = (size_t)&debug;
1949 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1950 size_t *ptr = (size_t *) app.dynv[i+1];
1951 *ptr = (size_t)&debug;
1952 }
1953 }
1954
1955 /* This must be done before final relocations, since it calls
1956 * malloc, which may be provided by the application. Calling any
1957 * application code prior to the jump to its entry point is not
1958 * valid in our model and does not work with FDPIC, where there
1959 * are additional relocation-like fixups that only the entry point
1960 * code can see to perform. */
1961 main_ctor_queue = queue_ctors(&app);
1962
1963 /* Initial TLS must also be allocated before final relocations
1964 * might result in calloc being a call to application code. */
1965 update_tls_size();
1966 void *initial_tls = builtin_tls;
1967 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1968 initial_tls = calloc(libc.tls_size, 1);
1969 if (!initial_tls) {
1970 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1971 argv[0], libc.tls_size);
1972 _exit(127);
1973 }
1974 }
1975 static_tls_cnt = tls_cnt;
1976
1977 /* The main program must be relocated LAST since it may contain
1978 * copy relocations which depend on libraries' relocations. */
1979 reloc_all(app.next);
1980 reloc_all(&app);
1981
1982 /* Actual copying to new TLS needs to happen after relocations,
1983 * since the TLS images might have contained relocated addresses. */
1984 if (initial_tls != builtin_tls) {
1985 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1986 a_crash();
1987 }
1988 } else {
1989 size_t tmp_tls_size = libc.tls_size;
1990 pthread_t self = __pthread_self();
1991 /* Temporarily set the tls size to the full size of
1992 * builtin_tls so that __copy_tls will use the same layout
1993 * as it did for before. Then check, just to be safe. */
1994 libc.tls_size = sizeof builtin_tls;
1995 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1996 libc.tls_size = tmp_tls_size;
1997 }
1998
1999 if (ldso_fail) _exit(127);
2000 if (ldd_mode) _exit(0);
2001
2002 /* Determine if malloc was interposed by a replacement implementation
2003 * so that calloc and the memalign family can harden against the
2004 * possibility of incomplete replacement. */
2005 if (find_sym(head, "malloc", 1).dso != &ldso)
2006 __malloc_replaced = 1;
2007 if (find_sym(head, "aligned_alloc", 1).dso != &ldso)
2008 __aligned_alloc_replaced = 1;
2009
2010 /* Switch to runtime mode: any further failures in the dynamic
2011 * linker are a reportable failure rather than a fatal startup
2012 * error. */
2013 runtime = 1;
2014
2015 debug.ver = 1;
2016 debug.bp = dl_debug_state;
2017 debug.head = head;
2018 debug.base = ldso.base;
2019 debug.state = RT_CONSISTENT;
2020 _dl_debug_state();
2021
2022 if (replace_argv0) argv[0] = replace_argv0;
2023
2024 errno = 0;
2025
2026 CRTJMP((void *)aux[AT_ENTRY], argv-1);
2027 for(;;);
2028 }
2029
2030 static void prepare_lazy(struct dso *p)
2031 {
2032 size_t dyn[DYN_CNT], n, flags1=0;
2033 decode_vec(p->dynv, dyn, DYN_CNT);
2034 search_vec(p->dynv, &flags1, DT_FLAGS_1);
2035 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
2036 return;
2037 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
2038 if (NEED_MIPS_GOT_RELOCS) {
2039 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
2040 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
2041 n += i-j;
2042 }
2043 p->lazy = calloc(n, 3*sizeof(size_t));
2044 if (!p->lazy) {
2045 error("Error preparing lazy relocation for %s: %m", p->name);
2046 longjmp(*rtld_fail, 1);
2047 }
2048 p->lazy_next = lazy_head;
2049 lazy_head = p;
2050 }
2051
2052 void *dlopen(const char *file, int mode)
2053 {
2054 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
2055 struct tls_module *orig_tls_tail;
2056 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
2057 size_t i;
2058 int cs;
2059 jmp_buf jb;
2060 struct dso **volatile ctor_queue = 0;
2061
2062 if (!file) return head;
2063
2064 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
2065 pthread_rwlock_wrlock(&lock);
2066 __inhibit_ptc();
2067
2068 debug.state = RT_ADD;
2069 _dl_debug_state();
2070
2071 p = 0;
2072 if (shutting_down) {
2073 error("Cannot dlopen while program is exiting.");
2074 goto end;
2075 }
2076 orig_tls_tail = tls_tail;
2077 orig_tls_cnt = tls_cnt;
2078 orig_tls_offset = tls_offset;
2079 orig_tls_align = tls_align;
2080 orig_lazy_head = lazy_head;
2081 orig_syms_tail = syms_tail;
2082 orig_tail = tail;
2083 noload = mode & RTLD_NOLOAD;
2084
2085 rtld_fail = &jb;
2086 if (setjmp(*rtld_fail)) {
2087 /* Clean up anything new that was (partially) loaded */
2088 revert_syms(orig_syms_tail);
2089 for (p=orig_tail->next; p; p=next) {
2090 next = p->next;
2091 while (p->td_index) {
2092 void *tmp = p->td_index->next;
2093 free(p->td_index);
2094 p->td_index = tmp;
2095 }
2096 free(p->funcdescs);
2097 if (p->rpath != p->rpath_orig)
2098 free(p->rpath);
2099 free(p->deps);
2100 unmap_library(p);
2101 free(p);
2102 }
2103 free(ctor_queue);
2104 ctor_queue = 0;
2105 if (!orig_tls_tail) libc.tls_head = 0;
2106 tls_tail = orig_tls_tail;
2107 if (tls_tail) tls_tail->next = 0;
2108 tls_cnt = orig_tls_cnt;
2109 tls_offset = orig_tls_offset;
2110 tls_align = orig_tls_align;
2111 lazy_head = orig_lazy_head;
2112 tail = orig_tail;
2113 tail->next = 0;
2114 p = 0;
2115 goto end;
2116 } else p = load_library(file, head);
2117
2118 if (!p) {
2119 error(noload ?
2120 "Library %s is not already loaded" :
2121 "Error loading shared library %s: %m",
2122 file);
2123 goto end;
2124 }
2125
2126 /* First load handling */
2127 load_deps(p);
2128 extend_bfs_deps(p);
2129 pthread_mutex_lock(&init_fini_lock);
2130 int constructed = p->constructed;
2131 pthread_mutex_unlock(&init_fini_lock);
2132 if (!constructed) ctor_queue = queue_ctors(p);
2133 if (!p->relocated && (mode & RTLD_LAZY)) {
2134 prepare_lazy(p);
2135 for (i=0; p->deps[i]; i++)
2136 if (!p->deps[i]->relocated)
2137 prepare_lazy(p->deps[i]);
2138 }
2139 if (!p->relocated || (mode & RTLD_GLOBAL)) {
2140 /* Make new symbols global, at least temporarily, so we can do
2141 * relocations. If not RTLD_GLOBAL, this is reverted below. */
2142 add_syms(p);
2143 for (i=0; p->deps[i]; i++)
2144 add_syms(p->deps[i]);
2145 }
2146 if (!p->relocated) {
2147 reloc_all(p);
2148 }
2149
2150 /* If RTLD_GLOBAL was not specified, undo any new additions
2151 * to the global symbol table. This is a nop if the library was
2152 * previously loaded and already global. */
2153 if (!(mode & RTLD_GLOBAL))
2154 revert_syms(orig_syms_tail);
2155
2156 /* Processing of deferred lazy relocations must not happen until
2157 * the new libraries are committed; otherwise we could end up with
2158 * relocations resolved to symbol definitions that get removed. */
2159 redo_lazy_relocs();
2160
2161 update_tls_size();
2162 if (tls_cnt != orig_tls_cnt)
2163 install_new_tls();
2164 orig_tail = tail;
2165 end:
2166 debug.state = RT_CONSISTENT;
2167 _dl_debug_state();
2168 __release_ptc();
2169 if (p) gencnt++;
2170 pthread_rwlock_unlock(&lock);
2171 if (ctor_queue) {
2172 do_init_fini(ctor_queue);
2173 free(ctor_queue);
2174 }
2175 pthread_setcancelstate(cs, 0);
2176 return p;
2177 }
2178
2179 hidden int __dl_invalid_handle(void *h)
2180 {
2181 struct dso *p;
2182 for (p=head; p; p=p->next) if (h==p) return 0;
2183 error("Invalid library handle %p", (void *)h);
2184 return 1;
2185 }
2186
2187 static void *addr2dso(size_t a)
2188 {
2189 struct dso *p;
2190 size_t i;
2191 if (DL_FDPIC) for (p=head; p; p=p->next) {
2192 i = count_syms(p);
2193 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
2194 return p;
2195 }
2196 for (p=head; p; p=p->next) {
2197 if (DL_FDPIC && p->loadmap) {
2198 for (i=0; i<p->loadmap->nsegs; i++) {
2199 if (a-p->loadmap->segs[i].p_vaddr
2200 < p->loadmap->segs[i].p_memsz)
2201 return p;
2202 }
2203 } else {
2204 Phdr *ph = p->phdr;
2205 size_t phcnt = p->phnum;
2206 size_t entsz = p->phentsize;
2207 size_t base = (size_t)p->base;
2208 for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
2209 if (ph->p_type != PT_LOAD) continue;
2210 if (a-base-ph->p_vaddr < ph->p_memsz)
2211 return p;
2212 }
2213 if (a-(size_t)p->map < p->map_len)
2214 return 0;
2215 }
2216 }
2217 return 0;
2218 }
2219
2220 static void *do_dlsym(struct dso *p, const char *s, void *ra)
2221 {
2222 int use_deps = 0;
2223 if (p == head || p == RTLD_DEFAULT) {
2224 p = head;
2225 } else if (p == RTLD_NEXT) {
2226 p = addr2dso((size_t)ra);
2227 if (!p) p=head;
2228 p = p->next;
2229 } else if (__dl_invalid_handle(p)) {
2230 return 0;
2231 } else
2232 use_deps = 1;
2233 struct symdef def = find_sym2(p, s, 0, use_deps);
2234 if (!def.sym) {
2235 error("Symbol not found: %s", s);
2236 return 0;
2237 }
2238 if ((def.sym->st_info&0xf) == STT_TLS)
2239 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
2240 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
2241 return def.dso->funcdescs + (def.sym - def.dso->syms);
2242 return laddr(def.dso, def.sym->st_value);
2243 }
2244
2245 int dladdr(const void *addr_arg, Dl_info *info)
2246 {
2247 size_t addr = (size_t)addr_arg;
2248 struct dso *p;
2249 Sym *sym, *bestsym;
2250 uint32_t nsym;
2251 char *strings;
2252 size_t best = 0;
2253 size_t besterr = -1;
2254
2255 pthread_rwlock_rdlock(&lock);
2256 p = addr2dso(addr);
2257 pthread_rwlock_unlock(&lock);
2258
2259 if (!p) return 0;
2260
2261 sym = p->syms;
2262 strings = p->strings;
2263 nsym = count_syms(p);
2264
2265 if (DL_FDPIC) {
2266 size_t idx = (addr-(size_t)p->funcdescs)
2267 / sizeof(*p->funcdescs);
2268 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
2269 best = (size_t)(p->funcdescs + idx);
2270 bestsym = sym + idx;
2271 besterr = 0;
2272 }
2273 }
2274
2275 if (!best) for (; nsym; nsym--, sym++) {
2276 if (sym->st_value
2277 && (1<<(sym->st_info&0xf) & OK_TYPES)
2278 && (1<<(sym->st_info>>4) & OK_BINDS)) {
2279 size_t symaddr = (size_t)laddr(p, sym->st_value);
2280 if (symaddr > addr || symaddr <= best)
2281 continue;
2282 best = symaddr;
2283 bestsym = sym;
2284 besterr = addr - symaddr;
2285 if (addr == symaddr)
2286 break;
2287 }
2288 }
2289
2290 if (best && besterr > bestsym->st_size-1) {
2291 best = 0;
2292 bestsym = 0;
2293 }
2294
2295 info->dli_fname = p->name;
2296 info->dli_fbase = p->map;
2297
2298 if (!best) {
2299 info->dli_sname = 0;
2300 info->dli_saddr = 0;
2301 return 1;
2302 }
2303
2304 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2305 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2306 info->dli_sname = strings + bestsym->st_name;
2307 info->dli_saddr = (void *)best;
2308
2309 return 1;
2310 }
2311
2312 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2313 {
2314 void *res;
2315 pthread_rwlock_rdlock(&lock);
2316 res = do_dlsym(p, s, ra);
2317 pthread_rwlock_unlock(&lock);
2318 return res;
2319 }
2320
2321 hidden void *__dlsym_redir_time64(void *restrict p, const char *restrict s, void *restrict ra)
2322 {
2323 #if _REDIR_TIME64
2324 const char *suffix, *suffix2 = "";
2325 char redir[36];
2326
2327 /* Map the symbol name to a time64 version of itself according to the
2328 * pattern used for naming the redirected time64 symbols. */
2329 size_t l = strnlen(s, sizeof redir);
2330 if (l<4 || l==sizeof redir) goto no_redir;
2331 if (s[l-2]=='_' && s[l-1]=='r') {
2332 l -= 2;
2333 suffix2 = s+l;
2334 }
2335 if (l<4) goto no_redir;
2336 if (!strcmp(s+l-4, "time")) suffix = "64";
2337 else suffix = "_time64";
2338
2339 /* Use the presence of the remapped symbol name in libc to determine
2340 * whether it's one that requires time64 redirection; replace if so. */
2341 snprintf(redir, sizeof redir, "__%.*s%s%s", (int)l, s, suffix, suffix2);
2342 if (find_sym(&ldso, redir, 1).sym) s = redir;
2343 no_redir:
2344 #endif
2345 return __dlsym(p, s, ra);
2346 }
2347
2348 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2349 {
2350 struct dso *current;
2351 struct dl_phdr_info info;
2352 int ret = 0;
2353 for(current = head; current;) {
2354 info.dlpi_addr = (uintptr_t)current->base;
2355 info.dlpi_name = current->name;
2356 info.dlpi_phdr = current->phdr;
2357 info.dlpi_phnum = current->phnum;
2358 info.dlpi_adds = gencnt;
2359 info.dlpi_subs = 0;
2360 info.dlpi_tls_modid = current->tls_id;
2361 info.dlpi_tls_data = !current->tls_id ? 0 :
2362 __tls_get_addr((tls_mod_off_t[]){current->tls_id,0});
2363
2364 ret = (callback)(&info, sizeof (info), data);
2365
2366 if (ret != 0) break;
2367
2368 pthread_rwlock_rdlock(&lock);
2369 current = current->next;
2370 pthread_rwlock_unlock(&lock);
2371 }
2372 return ret;
2373 }
2374
2375 static void error_impl(const char *fmt, ...)
2376 {
2377 va_list ap;
2378 va_start(ap, fmt);
2379 if (!runtime) {
2380 vdprintf(2, fmt, ap);
2381 dprintf(2, "\n");
2382 ldso_fail = 1;
2383 va_end(ap);
2384 return;
2385 }
2386 __dl_vseterr(fmt, ap);
2387 va_end(ap);
2388 }
2389
2390 static void error_noop(const char *fmt, ...)
2391 {
2392 }
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