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remove spurious repeated semicolon in fmemopen
[musl.git] / ldso / dynlink.c
blob6468f203cb69b1dbfb6c5731c4e3f7c650546c7e
1 #define _GNU_SOURCE
2 #define SYSCALL_NO_TLS 1
3 #include <stdio.h>
4 #include <stdlib.h>
5 #include <stdarg.h>
6 #include <stddef.h>
7 #include <string.h>
8 #include <unistd.h>
9 #include <stdint.h>
10 #include <elf.h>
11 #include <sys/mman.h>
12 #include <limits.h>
13 #include <fcntl.h>
14 #include <sys/stat.h>
15 #include <errno.h>
16 #include <link.h>
17 #include <setjmp.h>
18 #include <pthread.h>
19 #include <ctype.h>
20 #include <dlfcn.h>
21 #include <semaphore.h>
22 #include <sys/membarrier.h>
23 #include "pthread_impl.h"
24 #include "libc.h"
25 #include "dynlink.h"
26 #include "malloc_impl.h"
27
28 static void error(const char *, ...);
29
30 #define MAXP2(a,b) (-(-(a)&-(b)))
31 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
32
33 #define container_of(p,t,m) ((t*)((char *)(p)-offsetof(t,m)))
34 #define countof(a) ((sizeof (a))/(sizeof (a)[0]))
35
36 struct debug {
37 int ver;
38 void *head;
39 void (*bp)(void);
40 int state;
41 void *base;
42 };
43
44 struct td_index {
45 size_t args[2];
46 struct td_index *next;
47 };
48
49 struct dso {
50 #if DL_FDPIC
51 struct fdpic_loadmap *loadmap;
52 #else
53 unsigned char *base;
54 #endif
55 char *name;
56 size_t *dynv;
57 struct dso *next, *prev;
58
59 Phdr *phdr;
60 int phnum;
61 size_t phentsize;
62 Sym *syms;
63 Elf_Symndx *hashtab;
64 uint32_t *ghashtab;
65 int16_t *versym;
66 char *strings;
67 struct dso *syms_next, *lazy_next;
68 size_t *lazy, lazy_cnt;
69 unsigned char *map;
70 size_t map_len;
71 dev_t dev;
72 ino_t ino;
73 char relocated;
74 char constructed;
75 char kernel_mapped;
76 char mark;
77 char bfs_built;
78 char runtime_loaded;
79 struct dso **deps, *needed_by;
80 size_t ndeps_direct;
81 size_t next_dep;
82 int ctor_visitor;
83 char *rpath_orig, *rpath;
84 struct tls_module tls;
85 size_t tls_id;
86 size_t relro_start, relro_end;
87 uintptr_t *new_dtv;
88 unsigned char *new_tls;
89 struct td_index *td_index;
90 struct dso *fini_next;
91 char *shortname;
92 #if DL_FDPIC
93 unsigned char *base;
94 #else
95 struct fdpic_loadmap *loadmap;
96 #endif
97 struct funcdesc {
98 void *addr;
99 size_t *got;
100 } *funcdescs;
101 size_t *got;
102 char buf[];
103 };
104
105 struct symdef {
106 Sym *sym;
107 struct dso *dso;
108 };
109
110 typedef void (*stage3_func)(size_t *, size_t *);
111
112 static struct builtin_tls {
113 char c;
114 struct pthread pt;
115 void *space[16];
116 } builtin_tls[1];
117 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
118
119 #define ADDEND_LIMIT 4096
120 static size_t *saved_addends, *apply_addends_to;
121
122 static struct dso ldso;
123 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
124 static char *env_path, *sys_path;
125 static unsigned long long gencnt;
126 static int runtime;
127 static int ldd_mode;
128 static int ldso_fail;
129 static int noload;
130 static int shutting_down;
131 static jmp_buf *rtld_fail;
132 static pthread_rwlock_t lock;
133 static struct debug debug;
134 static struct tls_module *tls_tail;
135 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
136 static size_t static_tls_cnt;
137 static pthread_mutex_t init_fini_lock;
138 static pthread_cond_t ctor_cond;
139 static struct dso *builtin_deps[2];
140 static struct dso *const no_deps[1];
141 static struct dso *builtin_ctor_queue[4];
142 static struct dso **main_ctor_queue;
143 static struct fdpic_loadmap *app_loadmap;
144 static struct fdpic_dummy_loadmap app_dummy_loadmap;
145
146 struct debug *_dl_debug_addr = &debug;
147
148 extern hidden int __malloc_replaced;
149
150 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
151
152 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
153
154 weak_alias(__init_array_start, __init_array_end);
155 weak_alias(__fini_array_start, __fini_array_end);
156
157 static int dl_strcmp(const char *l, const char *r)
158 {
159 for (; *l==*r && *l; l++, r++);
160 return *(unsigned char *)l - *(unsigned char *)r;
161 }
162 #define strcmp(l,r) dl_strcmp(l,r)
163
164 /* Compute load address for a virtual address in a given dso. */
165 #if DL_FDPIC
166 static void *laddr(const struct dso *p, size_t v)
167 {
168 size_t j=0;
169 if (!p->loadmap) return p->base + v;
170 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
171 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
172 }
173 static void *laddr_pg(const struct dso *p, size_t v)
174 {
175 size_t j=0;
176 size_t pgsz = PAGE_SIZE;
177 if (!p->loadmap) return p->base + v;
178 for (j=0; ; j++) {
179 size_t a = p->loadmap->segs[j].p_vaddr;
180 size_t b = a + p->loadmap->segs[j].p_memsz;
181 a &= -pgsz;
182 b += pgsz-1;
183 b &= -pgsz;
184 if (v-a<b-a) break;
185 }
186 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
187 }
188 static void (*fdbarrier(void *p))()
189 {
190 void (*fd)();
191 __asm__("" : "=r"(fd) : "0"(p));
192 return fd;
193 }
194 #define fpaddr(p, v) fdbarrier((&(struct funcdesc){ \
195 laddr(p, v), (p)->got }))
196 #else
197 #define laddr(p, v) (void *)((p)->base + (v))
198 #define laddr_pg(p, v) laddr(p, v)
199 #define fpaddr(p, v) ((void (*)())laddr(p, v))
200 #endif
201
202 static void decode_vec(size_t *v, size_t *a, size_t cnt)
203 {
204 size_t i;
205 for (i=0; i<cnt; i++) a[i] = 0;
206 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
207 a[0] |= 1UL<<v[0];
208 a[v[0]] = v[1];
209 }
210 }
211
212 static int search_vec(size_t *v, size_t *r, size_t key)
213 {
214 for (; v[0]!=key; v+=2)
215 if (!v[0]) return 0;
216 *r = v[1];
217 return 1;
218 }
219
220 static uint32_t sysv_hash(const char *s0)
221 {
222 const unsigned char *s = (void *)s0;
223 uint_fast32_t h = 0;
224 while (*s) {
225 h = 16*h + *s++;
226 h ^= h>>24 & 0xf0;
227 }
228 return h & 0xfffffff;
229 }
230
231 static uint32_t gnu_hash(const char *s0)
232 {
233 const unsigned char *s = (void *)s0;
234 uint_fast32_t h = 5381;
235 for (; *s; s++)
236 h += h*32 + *s;
237 return h;
238 }
239
240 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
241 {
242 size_t i;
243 Sym *syms = dso->syms;
244 Elf_Symndx *hashtab = dso->hashtab;
245 char *strings = dso->strings;
246 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
247 if ((!dso->versym || dso->versym[i] >= 0)
248 && (!strcmp(s, strings+syms[i].st_name)))
249 return syms+i;
250 }
251 return 0;
252 }
253
254 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
255 {
256 uint32_t nbuckets = hashtab[0];
257 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
258 uint32_t i = buckets[h1 % nbuckets];
259
260 if (!i) return 0;
261
262 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
263
264 for (h1 |= 1; ; i++) {
265 uint32_t h2 = *hashval++;
266 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
267 && !strcmp(s, dso->strings + dso->syms[i].st_name))
268 return dso->syms+i;
269 if (h2 & 1) break;
270 }
271
272 return 0;
273 }
274
275 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
276 {
277 const size_t *bloomwords = (const void *)(hashtab+4);
278 size_t f = bloomwords[fofs & (hashtab[2]-1)];
279 if (!(f & fmask)) return 0;
280
281 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
282 if (!(f & 1)) return 0;
283
284 return gnu_lookup(h1, hashtab, dso, s);
285 }
286
287 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
288 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
289
290 #ifndef ARCH_SYM_REJECT_UND
291 #define ARCH_SYM_REJECT_UND(s) 0
292 #endif
293
294 #if defined(__GNUC__)
295 __attribute__((always_inline))
296 #endif
297 static inline struct symdef find_sym2(struct dso *dso, const char *s, int need_def, int use_deps)
298 {
299 uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
300 size_t ghm = 1ul << gh % (8*sizeof(size_t));
301 struct symdef def = {0};
302 struct dso **deps = use_deps ? dso->deps : 0;
303 for (; dso; dso=use_deps ? *deps++ : dso->syms_next) {
304 Sym *sym;
305 if ((ght = dso->ghashtab)) {
306 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
307 } else {
308 if (!h) h = sysv_hash(s);
309 sym = sysv_lookup(s, h, dso);
310 }
311 if (!sym) continue;
312 if (!sym->st_shndx)
313 if (need_def || (sym->st_info&0xf) == STT_TLS
314 || ARCH_SYM_REJECT_UND(sym))
315 continue;
316 if (!sym->st_value)
317 if ((sym->st_info&0xf) != STT_TLS)
318 continue;
319 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
320 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
321 def.sym = sym;
322 def.dso = dso;
323 break;
324 }
325 return def;
326 }
327
328 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
329 {
330 return find_sym2(dso, s, need_def, 0);
331 }
332
333 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
334 {
335 unsigned char *base = dso->base;
336 Sym *syms = dso->syms;
337 char *strings = dso->strings;
338 Sym *sym;
339 const char *name;
340 void *ctx;
341 int type;
342 int sym_index;
343 struct symdef def;
344 size_t *reloc_addr;
345 size_t sym_val;
346 size_t tls_val;
347 size_t addend;
348 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
349
350 if (dso == &ldso) {
351 /* Only ldso's REL table needs addend saving/reuse. */
352 if (rel == apply_addends_to)
353 reuse_addends = 1;
354 skip_relative = 1;
355 }
356
357 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
358 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
359 type = R_TYPE(rel[1]);
360 if (type == REL_NONE) continue;
361 reloc_addr = laddr(dso, rel[0]);
362
363 if (stride > 2) {
364 addend = rel[2];
365 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
366 addend = 0;
367 } else if (reuse_addends) {
368 /* Save original addend in stage 2 where the dso
369 * chain consists of just ldso; otherwise read back
370 * saved addend since the inline one was clobbered. */
371 if (head==&ldso)
372 saved_addends[save_slot] = *reloc_addr;
373 addend = saved_addends[save_slot++];
374 } else {
375 addend = *reloc_addr;
376 }
377
378 sym_index = R_SYM(rel[1]);
379 if (sym_index) {
380 sym = syms + sym_index;
381 name = strings + sym->st_name;
382 ctx = type==REL_COPY ? head->syms_next : head;
383 def = (sym->st_info>>4) == STB_LOCAL
384 ? (struct symdef){ .dso = dso, .sym = sym }
385 : find_sym(ctx, name, type==REL_PLT);
386 if (!def.sym && (sym->st_shndx != SHN_UNDEF
387 || sym->st_info>>4 != STB_WEAK)) {
388 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
389 dso->lazy[3*dso->lazy_cnt+0] = rel[0];
390 dso->lazy[3*dso->lazy_cnt+1] = rel[1];
391 dso->lazy[3*dso->lazy_cnt+2] = addend;
392 dso->lazy_cnt++;
393 continue;
394 }
395 error("Error relocating %s: %s: symbol not found",
396 dso->name, name);
397 if (runtime) longjmp(*rtld_fail, 1);
398 continue;
399 }
400 } else {
401 sym = 0;
402 def.sym = 0;
403 def.dso = dso;
404 }
405
406 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
407 tls_val = def.sym ? def.sym->st_value : 0;
408
409 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
410 && def.dso->tls_id > static_tls_cnt) {
411 error("Error relocating %s: %s: initial-exec TLS "
412 "resolves to dynamic definition in %s",
413 dso->name, name, def.dso->name);
414 longjmp(*rtld_fail, 1);
415 }
416
417 switch(type) {
418 case REL_OFFSET:
419 addend -= (size_t)reloc_addr;
420 case REL_SYMBOLIC:
421 case REL_GOT:
422 case REL_PLT:
423 *reloc_addr = sym_val + addend;
424 break;
425 case REL_USYMBOLIC:
426 memcpy(reloc_addr, &(size_t){sym_val + addend}, sizeof(size_t));
427 break;
428 case REL_RELATIVE:
429 *reloc_addr = (size_t)base + addend;
430 break;
431 case REL_SYM_OR_REL:
432 if (sym) *reloc_addr = sym_val + addend;
433 else *reloc_addr = (size_t)base + addend;
434 break;
435 case REL_COPY:
436 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
437 break;
438 case REL_OFFSET32:
439 *(uint32_t *)reloc_addr = sym_val + addend
440 - (size_t)reloc_addr;
441 break;
442 case REL_FUNCDESC:
443 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
444 + (def.sym - def.dso->syms)) : 0;
445 break;
446 case REL_FUNCDESC_VAL:
447 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
448 else *reloc_addr = sym_val;
449 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
450 break;
451 case REL_DTPMOD:
452 *reloc_addr = def.dso->tls_id;
453 break;
454 case REL_DTPOFF:
455 *reloc_addr = tls_val + addend - DTP_OFFSET;
456 break;
457 #ifdef TLS_ABOVE_TP
458 case REL_TPOFF:
459 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
460 break;
461 #else
462 case REL_TPOFF:
463 *reloc_addr = tls_val - def.dso->tls.offset + addend;
464 break;
465 case REL_TPOFF_NEG:
466 *reloc_addr = def.dso->tls.offset - tls_val + addend;
467 break;
468 #endif
469 case REL_TLSDESC:
470 if (stride<3) addend = reloc_addr[1];
471 if (def.dso->tls_id > static_tls_cnt) {
472 struct td_index *new = malloc(sizeof *new);
473 if (!new) {
474 error(
475 "Error relocating %s: cannot allocate TLSDESC for %s",
476 dso->name, sym ? name : "(local)" );
477 longjmp(*rtld_fail, 1);
478 }
479 new->next = dso->td_index;
480 dso->td_index = new;
481 new->args[0] = def.dso->tls_id;
482 new->args[1] = tls_val + addend - DTP_OFFSET;
483 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
484 reloc_addr[1] = (size_t)new;
485 } else {
486 reloc_addr[0] = (size_t)__tlsdesc_static;
487 #ifdef TLS_ABOVE_TP
488 reloc_addr[1] = tls_val + def.dso->tls.offset
489 + TPOFF_K + addend;
490 #else
491 reloc_addr[1] = tls_val - def.dso->tls.offset
492 + addend;
493 #endif
494 }
495 #ifdef TLSDESC_BACKWARDS
496 /* Some archs (32-bit ARM at least) invert the order of
497 * the descriptor members. Fix them up here. */
498 size_t tmp = reloc_addr[0];
499 reloc_addr[0] = reloc_addr[1];
500 reloc_addr[1] = tmp;
501 #endif
502 break;
503 default:
504 error("Error relocating %s: unsupported relocation type %d",
505 dso->name, type);
506 if (runtime) longjmp(*rtld_fail, 1);
507 continue;
508 }
509 }
510 }
511
512 static void redo_lazy_relocs()
513 {
514 struct dso *p = lazy_head, *next;
515 lazy_head = 0;
516 for (; p; p=next) {
517 next = p->lazy_next;
518 size_t size = p->lazy_cnt*3*sizeof(size_t);
519 p->lazy_cnt = 0;
520 do_relocs(p, p->lazy, size, 3);
521 if (p->lazy_cnt) {
522 p->lazy_next = lazy_head;
523 lazy_head = p;
524 } else {
525 free(p->lazy);
526 p->lazy = 0;
527 p->lazy_next = 0;
528 }
529 }
530 }
531
532 /* A huge hack: to make up for the wastefulness of shared libraries
533 * needing at least a page of dirty memory even if they have no global
534 * data, we reclaim the gaps at the beginning and end of writable maps
535 * and "donate" them to the heap. */
536
537 static void reclaim(struct dso *dso, size_t start, size_t end)
538 {
539 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
540 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
541 if (start >= end) return;
542 char *base = laddr_pg(dso, start);
543 __malloc_donate(base, base+(end-start));
544 }
545
546 static void reclaim_gaps(struct dso *dso)
547 {
548 Phdr *ph = dso->phdr;
549 size_t phcnt = dso->phnum;
550
551 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
552 if (ph->p_type!=PT_LOAD) continue;
553 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
554 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
555 reclaim(dso, ph->p_vaddr+ph->p_memsz,
556 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
557 }
558 }
559
560 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
561 {
562 static int no_map_fixed;
563 char *q;
564 if (!no_map_fixed) {
565 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
566 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
567 return q;
568 no_map_fixed = 1;
569 }
570 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
571 if (flags & MAP_ANONYMOUS) {
572 memset(p, 0, n);
573 return p;
574 }
575 ssize_t r;
576 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
577 for (q=p; n; q+=r, off+=r, n-=r) {
578 r = read(fd, q, n);
579 if (r < 0 && errno != EINTR) return MAP_FAILED;
580 if (!r) {
581 memset(q, 0, n);
582 break;
583 }
584 }
585 return p;
586 }
587
588 static void unmap_library(struct dso *dso)
589 {
590 if (dso->loadmap) {
591 size_t i;
592 for (i=0; i<dso->loadmap->nsegs; i++) {
593 if (!dso->loadmap->segs[i].p_memsz)
594 continue;
595 munmap((void *)dso->loadmap->segs[i].addr,
596 dso->loadmap->segs[i].p_memsz);
597 }
598 free(dso->loadmap);
599 } else if (dso->map && dso->map_len) {
600 munmap(dso->map, dso->map_len);
601 }
602 }
603
604 static void *map_library(int fd, struct dso *dso)
605 {
606 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
607 void *allocated_buf=0;
608 size_t phsize;
609 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
610 size_t this_min, this_max;
611 size_t nsegs = 0;
612 off_t off_start;
613 Ehdr *eh;
614 Phdr *ph, *ph0;
615 unsigned prot;
616 unsigned char *map=MAP_FAILED, *base;
617 size_t dyn=0;
618 size_t tls_image=0;
619 size_t i;
620
621 ssize_t l = read(fd, buf, sizeof buf);
622 eh = buf;
623 if (l<0) return 0;
624 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
625 goto noexec;
626 phsize = eh->e_phentsize * eh->e_phnum;
627 if (phsize > sizeof buf - sizeof *eh) {
628 allocated_buf = malloc(phsize);
629 if (!allocated_buf) return 0;
630 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
631 if (l < 0) goto error;
632 if (l != phsize) goto noexec;
633 ph = ph0 = allocated_buf;
634 } else if (eh->e_phoff + phsize > l) {
635 l = pread(fd, buf+1, phsize, eh->e_phoff);
636 if (l < 0) goto error;
637 if (l != phsize) goto noexec;
638 ph = ph0 = (void *)(buf + 1);
639 } else {
640 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
641 }
642 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
643 if (ph->p_type == PT_DYNAMIC) {
644 dyn = ph->p_vaddr;
645 } else if (ph->p_type == PT_TLS) {
646 tls_image = ph->p_vaddr;
647 dso->tls.align = ph->p_align;
648 dso->tls.len = ph->p_filesz;
649 dso->tls.size = ph->p_memsz;
650 } else if (ph->p_type == PT_GNU_RELRO) {
651 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
652 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
653 } else if (ph->p_type == PT_GNU_STACK) {
654 if (!runtime && ph->p_memsz > __default_stacksize) {
655 __default_stacksize =
656 ph->p_memsz < DEFAULT_STACK_MAX ?
657 ph->p_memsz : DEFAULT_STACK_MAX;
658 }
659 }
660 if (ph->p_type != PT_LOAD) continue;
661 nsegs++;
662 if (ph->p_vaddr < addr_min) {
663 addr_min = ph->p_vaddr;
664 off_start = ph->p_offset;
665 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
666 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
667 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
668 }
669 if (ph->p_vaddr+ph->p_memsz > addr_max) {
670 addr_max = ph->p_vaddr+ph->p_memsz;
671 }
672 }
673 if (!dyn) goto noexec;
674 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
675 dso->loadmap = calloc(1, sizeof *dso->loadmap
676 + nsegs * sizeof *dso->loadmap->segs);
677 if (!dso->loadmap) goto error;
678 dso->loadmap->nsegs = nsegs;
679 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
680 if (ph->p_type != PT_LOAD) continue;
681 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
682 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
683 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
684 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
685 prot, MAP_PRIVATE,
686 fd, ph->p_offset & -PAGE_SIZE);
687 if (map == MAP_FAILED) {
688 unmap_library(dso);
689 goto error;
690 }
691 dso->loadmap->segs[i].addr = (size_t)map +
692 (ph->p_vaddr & PAGE_SIZE-1);
693 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
694 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
695 i++;
696 if (prot & PROT_WRITE) {
697 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
698 + ph->p_filesz;
699 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
700 size_t pgend = brk + ph->p_memsz - ph->p_filesz
701 + PAGE_SIZE-1 & -PAGE_SIZE;
702 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
703 pgend-pgbrk, prot,
704 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
705 -1, off_start) == MAP_FAILED)
706 goto error;
707 memset(map + brk, 0, pgbrk-brk);
708 }
709 }
710 map = (void *)dso->loadmap->segs[0].addr;
711 map_len = 0;
712 goto done_mapping;
713 }
714 addr_max += PAGE_SIZE-1;
715 addr_max &= -PAGE_SIZE;
716 addr_min &= -PAGE_SIZE;
717 off_start &= -PAGE_SIZE;
718 map_len = addr_max - addr_min + off_start;
719 /* The first time, we map too much, possibly even more than
720 * the length of the file. This is okay because we will not
721 * use the invalid part; we just need to reserve the right
722 * amount of virtual address space to map over later. */
723 map = DL_NOMMU_SUPPORT
724 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
725 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
726 : mmap((void *)addr_min, map_len, prot,
727 MAP_PRIVATE, fd, off_start);
728 if (map==MAP_FAILED) goto error;
729 dso->map = map;
730 dso->map_len = map_len;
731 /* If the loaded file is not relocatable and the requested address is
732 * not available, then the load operation must fail. */
733 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
734 errno = EBUSY;
735 goto error;
736 }
737 base = map - addr_min;
738 dso->phdr = 0;
739 dso->phnum = 0;
740 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
741 if (ph->p_type != PT_LOAD) continue;
742 /* Check if the programs headers are in this load segment, and
743 * if so, record the address for use by dl_iterate_phdr. */
744 if (!dso->phdr && eh->e_phoff >= ph->p_offset
745 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
746 dso->phdr = (void *)(base + ph->p_vaddr
747 + (eh->e_phoff-ph->p_offset));
748 dso->phnum = eh->e_phnum;
749 dso->phentsize = eh->e_phentsize;
750 }
751 this_min = ph->p_vaddr & -PAGE_SIZE;
752 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
753 off_start = ph->p_offset & -PAGE_SIZE;
754 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
755 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
756 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
757 /* Reuse the existing mapping for the lowest-address LOAD */
758 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
759 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
760 goto error;
761 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
762 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
763 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
764 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
765 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)
766 goto error;
767 }
768 }
769 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
770 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
771 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
772 && errno != ENOSYS)
773 goto error;
774 break;
775 }
776 done_mapping:
777 dso->base = base;
778 dso->dynv = laddr(dso, dyn);
779 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
780 free(allocated_buf);
781 return map;
782 noexec:
783 errno = ENOEXEC;
784 error:
785 if (map!=MAP_FAILED) unmap_library(dso);
786 free(allocated_buf);
787 return 0;
788 }
789
790 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
791 {
792 size_t l;
793 int fd;
794 for (;;) {
795 s += strspn(s, ":\n");
796 l = strcspn(s, ":\n");
797 if (l-1 >= INT_MAX) return -1;
798 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
799 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
800 switch (errno) {
801 case ENOENT:
802 case ENOTDIR:
803 case EACCES:
804 case ENAMETOOLONG:
805 break;
806 default:
807 /* Any negative value but -1 will inhibit
808 * futher path search. */
809 return -2;
810 }
811 }
812 s += l;
813 }
814 }
815
816 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
817 {
818 size_t n, l;
819 const char *s, *t, *origin;
820 char *d;
821 if (p->rpath || !p->rpath_orig) return 0;
822 if (!strchr(p->rpath_orig, '$')) {
823 p->rpath = p->rpath_orig;
824 return 0;
825 }
826 n = 0;
827 s = p->rpath_orig;
828 while ((t=strchr(s, '$'))) {
829 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
830 return 0;
831 s = t+1;
832 n++;
833 }
834 if (n > SSIZE_MAX/PATH_MAX) return 0;
835
836 if (p->kernel_mapped) {
837 /* $ORIGIN searches cannot be performed for the main program
838 * when it is suid/sgid/AT_SECURE. This is because the
839 * pathname is under the control of the caller of execve.
840 * For libraries, however, $ORIGIN can be processed safely
841 * since the library's pathname came from a trusted source
842 * (either system paths or a call to dlopen). */
843 if (libc.secure)
844 return 0;
845 l = readlink("/proc/self/exe", buf, buf_size);
846 if (l == -1) switch (errno) {
847 case ENOENT:
848 case ENOTDIR:
849 case EACCES:
850 break;
851 default:
852 return -1;
853 }
854 if (l >= buf_size)
855 return 0;
856 buf[l] = 0;
857 origin = buf;
858 } else {
859 origin = p->name;
860 }
861 t = strrchr(origin, '/');
862 if (t) {
863 l = t-origin;
864 } else {
865 /* Normally p->name will always be an absolute or relative
866 * pathname containing at least one '/' character, but in the
867 * case where ldso was invoked as a command to execute a
868 * program in the working directory, app.name may not. Fix. */
869 origin = ".";
870 l = 1;
871 }
872 /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
873 if (libc.secure && *origin != '/')
874 return 0;
875 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
876 if (!p->rpath) return -1;
877
878 d = p->rpath;
879 s = p->rpath_orig;
880 while ((t=strchr(s, '$'))) {
881 memcpy(d, s, t-s);
882 d += t-s;
883 memcpy(d, origin, l);
884 d += l;
885 /* It was determined previously that the '$' is followed
886 * either by "ORIGIN" or "{ORIGIN}". */
887 s = t + 7 + 2*(t[1]=='{');
888 }
889 strcpy(d, s);
890 return 0;
891 }
892
893 static void decode_dyn(struct dso *p)
894 {
895 size_t dyn[DYN_CNT];
896 decode_vec(p->dynv, dyn, DYN_CNT);
897 p->syms = laddr(p, dyn[DT_SYMTAB]);
898 p->strings = laddr(p, dyn[DT_STRTAB]);
899 if (dyn[0]&(1<<DT_HASH))
900 p->hashtab = laddr(p, dyn[DT_HASH]);
901 if (dyn[0]&(1<<DT_RPATH))
902 p->rpath_orig = p->strings + dyn[DT_RPATH];
903 if (dyn[0]&(1<<DT_RUNPATH))
904 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
905 if (dyn[0]&(1<<DT_PLTGOT))
906 p->got = laddr(p, dyn[DT_PLTGOT]);
907 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
908 p->ghashtab = laddr(p, *dyn);
909 if (search_vec(p->dynv, dyn, DT_VERSYM))
910 p->versym = laddr(p, *dyn);
911 }
912
913 static size_t count_syms(struct dso *p)
914 {
915 if (p->hashtab) return p->hashtab[1];
916
917 size_t nsym, i;
918 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
919 uint32_t *hashval;
920 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
921 if (buckets[i] > nsym)
922 nsym = buckets[i];
923 }
924 if (nsym) {
925 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
926 do nsym++;
927 while (!(*hashval++ & 1));
928 }
929 return nsym;
930 }
931
932 static void *dl_mmap(size_t n)
933 {
934 void *p;
935 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
936 #ifdef SYS_mmap2
937 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
938 #else
939 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
940 #endif
941 return (unsigned long)p > -4096UL ? 0 : p;
942 }
943
944 static void makefuncdescs(struct dso *p)
945 {
946 static int self_done;
947 size_t nsym = count_syms(p);
948 size_t i, size = nsym * sizeof(*p->funcdescs);
949
950 if (!self_done) {
951 p->funcdescs = dl_mmap(size);
952 self_done = 1;
953 } else {
954 p->funcdescs = malloc(size);
955 }
956 if (!p->funcdescs) {
957 if (!runtime) a_crash();
958 error("Error allocating function descriptors for %s", p->name);
959 longjmp(*rtld_fail, 1);
960 }
961 for (i=0; i<nsym; i++) {
962 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
963 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
964 p->funcdescs[i].got = p->got;
965 } else {
966 p->funcdescs[i].addr = 0;
967 p->funcdescs[i].got = 0;
968 }
969 }
970 }
971
972 static struct dso *load_library(const char *name, struct dso *needed_by)
973 {
974 char buf[2*NAME_MAX+2];
975 const char *pathname;
976 unsigned char *map;
977 struct dso *p, temp_dso = {0};
978 int fd;
979 struct stat st;
980 size_t alloc_size;
981 int n_th = 0;
982 int is_self = 0;
983
984 if (!*name) {
985 errno = EINVAL;
986 return 0;
987 }
988
989 /* Catch and block attempts to reload the implementation itself */
990 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
991 static const char reserved[] =
992 "c.pthread.rt.m.dl.util.xnet.";
993 const char *rp, *next;
994 for (rp=reserved; *rp; rp=next) {
995 next = strchr(rp, '.') + 1;
996 if (strncmp(name+3, rp, next-rp) == 0)
997 break;
998 }
999 if (*rp) {
1000 if (ldd_mode) {
1001 /* Track which names have been resolved
1002 * and only report each one once. */
1003 static unsigned reported;
1004 unsigned mask = 1U<<(rp-reserved);
1005 if (!(reported & mask)) {
1006 reported |= mask;
1007 dprintf(1, "\t%s => %s (%p)\n",
1008 name, ldso.name,
1009 ldso.base);
1010 }
1011 }
1012 is_self = 1;
1013 }
1014 }
1015 if (!strcmp(name, ldso.name)) is_self = 1;
1016 if (is_self) {
1017 if (!ldso.prev) {
1018 tail->next = &ldso;
1019 ldso.prev = tail;
1020 tail = &ldso;
1021 }
1022 return &ldso;
1023 }
1024 if (strchr(name, '/')) {
1025 pathname = name;
1026 fd = open(name, O_RDONLY|O_CLOEXEC);
1027 } else {
1028 /* Search for the name to see if it's already loaded */
1029 for (p=head->next; p; p=p->next) {
1030 if (p->shortname && !strcmp(p->shortname, name)) {
1031 return p;
1032 }
1033 }
1034 if (strlen(name) > NAME_MAX) return 0;
1035 fd = -1;
1036 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
1037 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
1038 if (fixup_rpath(p, buf, sizeof buf) < 0)
1039 fd = -2; /* Inhibit further search. */
1040 if (p->rpath)
1041 fd = path_open(name, p->rpath, buf, sizeof buf);
1042 }
1043 if (fd == -1) {
1044 if (!sys_path) {
1045 char *prefix = 0;
1046 size_t prefix_len;
1047 if (ldso.name[0]=='/') {
1048 char *s, *t, *z;
1049 for (s=t=z=ldso.name; *s; s++)
1050 if (*s=='/') z=t, t=s;
1051 prefix_len = z-ldso.name;
1052 if (prefix_len < PATH_MAX)
1053 prefix = ldso.name;
1054 }
1055 if (!prefix) {
1056 prefix = "";
1057 prefix_len = 0;
1058 }
1059 char etc_ldso_path[prefix_len + 1
1060 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1061 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1062 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1063 (int)prefix_len, prefix);
1064 FILE *f = fopen(etc_ldso_path, "rbe");
1065 if (f) {
1066 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1067 free(sys_path);
1068 sys_path = "";
1069 }
1070 fclose(f);
1071 } else if (errno != ENOENT) {
1072 sys_path = "";
1073 }
1074 }
1075 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1076 fd = path_open(name, sys_path, buf, sizeof buf);
1077 }
1078 pathname = buf;
1079 }
1080 if (fd < 0) return 0;
1081 if (fstat(fd, &st) < 0) {
1082 close(fd);
1083 return 0;
1084 }
1085 for (p=head->next; p; p=p->next) {
1086 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1087 /* If this library was previously loaded with a
1088 * pathname but a search found the same inode,
1089 * setup its shortname so it can be found by name. */
1090 if (!p->shortname && pathname != name)
1091 p->shortname = strrchr(p->name, '/')+1;
1092 close(fd);
1093 return p;
1094 }
1095 }
1096 map = noload ? 0 : map_library(fd, &temp_dso);
1097 close(fd);
1098 if (!map) return 0;
1099
1100 /* Avoid the danger of getting two versions of libc mapped into the
1101 * same process when an absolute pathname was used. The symbols
1102 * checked are chosen to catch both musl and glibc, and to avoid
1103 * false positives from interposition-hack libraries. */
1104 decode_dyn(&temp_dso);
1105 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1106 find_sym(&temp_dso, "stdin", 1).sym) {
1107 unmap_library(&temp_dso);
1108 return load_library("libc.so", needed_by);
1109 }
1110 /* Past this point, if we haven't reached runtime yet, ldso has
1111 * committed either to use the mapped library or to abort execution.
1112 * Unmapping is not possible, so we can safely reclaim gaps. */
1113 if (!runtime) reclaim_gaps(&temp_dso);
1114
1115 /* Allocate storage for the new DSO. When there is TLS, this
1116 * storage must include a reservation for all pre-existing
1117 * threads to obtain copies of both the new TLS, and an
1118 * extended DTV capable of storing an additional slot for
1119 * the newly-loaded DSO. */
1120 alloc_size = sizeof *p + strlen(pathname) + 1;
1121 if (runtime && temp_dso.tls.image) {
1122 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1123 + sizeof(void *) * (tls_cnt+3);
1124 n_th = libc.threads_minus_1 + 1;
1125 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1126 else alloc_size += n_th * per_th;
1127 }
1128 p = calloc(1, alloc_size);
1129 if (!p) {
1130 unmap_library(&temp_dso);
1131 return 0;
1132 }
1133 memcpy(p, &temp_dso, sizeof temp_dso);
1134 p->dev = st.st_dev;
1135 p->ino = st.st_ino;
1136 p->needed_by = needed_by;
1137 p->name = p->buf;
1138 p->runtime_loaded = runtime;
1139 strcpy(p->name, pathname);
1140 /* Add a shortname only if name arg was not an explicit pathname. */
1141 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1142 if (p->tls.image) {
1143 p->tls_id = ++tls_cnt;
1144 tls_align = MAXP2(tls_align, p->tls.align);
1145 #ifdef TLS_ABOVE_TP
1146 p->tls.offset = tls_offset + ( (p->tls.align-1) &
1147 (-tls_offset + (uintptr_t)p->tls.image) );
1148 tls_offset = p->tls.offset + p->tls.size;
1149 #else
1150 tls_offset += p->tls.size + p->tls.align - 1;
1151 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1152 & (p->tls.align-1);
1153 p->tls.offset = tls_offset;
1154 #endif
1155 p->new_dtv = (void *)(-sizeof(size_t) &
1156 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1157 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1158 if (tls_tail) tls_tail->next = &p->tls;
1159 else libc.tls_head = &p->tls;
1160 tls_tail = &p->tls;
1161 }
1162
1163 tail->next = p;
1164 p->prev = tail;
1165 tail = p;
1166
1167 if (DL_FDPIC) makefuncdescs(p);
1168
1169 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1170
1171 return p;
1172 }
1173
1174 static void load_direct_deps(struct dso *p)
1175 {
1176 size_t i, cnt=0;
1177
1178 if (p->deps) return;
1179 /* For head, all preloads are direct pseudo-dependencies.
1180 * Count and include them now to avoid realloc later. */
1181 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1182 cnt++;
1183 for (i=0; p->dynv[i]; i+=2)
1184 if (p->dynv[i] == DT_NEEDED) cnt++;
1185 /* Use builtin buffer for apps with no external deps, to
1186 * preserve property of no runtime failure paths. */
1187 p->deps = (p==head && cnt<2) ? builtin_deps :
1188 calloc(cnt+1, sizeof *p->deps);
1189 if (!p->deps) {
1190 error("Error loading dependencies for %s", p->name);
1191 if (runtime) longjmp(*rtld_fail, 1);
1192 }
1193 cnt=0;
1194 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1195 p->deps[cnt++] = q;
1196 for (i=0; p->dynv[i]; i+=2) {
1197 if (p->dynv[i] != DT_NEEDED) continue;
1198 struct dso *dep = load_library(p->strings + p->dynv[i+1], p);
1199 if (!dep) {
1200 error("Error loading shared library %s: %m (needed by %s)",
1201 p->strings + p->dynv[i+1], p->name);
1202 if (runtime) longjmp(*rtld_fail, 1);
1203 continue;
1204 }
1205 p->deps[cnt++] = dep;
1206 }
1207 p->deps[cnt] = 0;
1208 p->ndeps_direct = cnt;
1209 }
1210
1211 static void load_deps(struct dso *p)
1212 {
1213 if (p->deps) return;
1214 for (; p; p=p->next)
1215 load_direct_deps(p);
1216 }
1217
1218 static void extend_bfs_deps(struct dso *p)
1219 {
1220 size_t i, j, cnt, ndeps_all;
1221 struct dso **tmp;
1222
1223 /* Can't use realloc if the original p->deps was allocated at
1224 * program entry and malloc has been replaced, or if it's
1225 * the builtin non-allocated trivial main program deps array. */
1226 int no_realloc = (__malloc_replaced && !p->runtime_loaded)
1227 || p->deps == builtin_deps;
1228
1229 if (p->bfs_built) return;
1230 ndeps_all = p->ndeps_direct;
1231
1232 /* Mark existing (direct) deps so they won't be duplicated. */
1233 for (i=0; p->deps[i]; i++)
1234 p->deps[i]->mark = 1;
1235
1236 /* For each dependency already in the list, copy its list of direct
1237 * dependencies to the list, excluding any items already in the
1238 * list. Note that the list this loop iterates over will grow during
1239 * the loop, but since duplicates are excluded, growth is bounded. */
1240 for (i=0; p->deps[i]; i++) {
1241 struct dso *dep = p->deps[i];
1242 for (j=cnt=0; j<dep->ndeps_direct; j++)
1243 if (!dep->deps[j]->mark) cnt++;
1244 tmp = no_realloc ?
1245 malloc(sizeof(*tmp) * (ndeps_all+cnt+1)) :
1246 realloc(p->deps, sizeof(*tmp) * (ndeps_all+cnt+1));
1247 if (!tmp) {
1248 error("Error recording dependencies for %s", p->name);
1249 if (runtime) longjmp(*rtld_fail, 1);
1250 continue;
1251 }
1252 if (no_realloc) {
1253 memcpy(tmp, p->deps, sizeof(*tmp) * (ndeps_all+1));
1254 no_realloc = 0;
1255 }
1256 p->deps = tmp;
1257 for (j=0; j<dep->ndeps_direct; j++) {
1258 if (dep->deps[j]->mark) continue;
1259 dep->deps[j]->mark = 1;
1260 p->deps[ndeps_all++] = dep->deps[j];
1261 }
1262 p->deps[ndeps_all] = 0;
1263 }
1264 p->bfs_built = 1;
1265 for (p=head; p; p=p->next)
1266 p->mark = 0;
1267 }
1268
1269 static void load_preload(char *s)
1270 {
1271 int tmp;
1272 char *z;
1273 for (z=s; *z; s=z) {
1274 for ( ; *s && (isspace(*s) || *s==':'); s++);
1275 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1276 tmp = *z;
1277 *z = 0;
1278 load_library(s, 0);
1279 *z = tmp;
1280 }
1281 }
1282
1283 static void add_syms(struct dso *p)
1284 {
1285 if (!p->syms_next && syms_tail != p) {
1286 syms_tail->syms_next = p;
1287 syms_tail = p;
1288 }
1289 }
1290
1291 static void revert_syms(struct dso *old_tail)
1292 {
1293 struct dso *p, *next;
1294 /* Chop off the tail of the list of dsos that participate in
1295 * the global symbol table, reverting them to RTLD_LOCAL. */
1296 for (p=old_tail; p; p=next) {
1297 next = p->syms_next;
1298 p->syms_next = 0;
1299 }
1300 syms_tail = old_tail;
1301 }
1302
1303 static void do_mips_relocs(struct dso *p, size_t *got)
1304 {
1305 size_t i, j, rel[2];
1306 unsigned char *base = p->base;
1307 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1308 if (p==&ldso) {
1309 got += i;
1310 } else {
1311 while (i--) *got++ += (size_t)base;
1312 }
1313 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1314 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1315 Sym *sym = p->syms + j;
1316 rel[0] = (unsigned char *)got - base;
1317 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1318 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1319 do_relocs(p, rel, sizeof rel, 2);
1320 }
1321 }
1322
1323 static void reloc_all(struct dso *p)
1324 {
1325 size_t dyn[DYN_CNT];
1326 for (; p; p=p->next) {
1327 if (p->relocated) continue;
1328 decode_vec(p->dynv, dyn, DYN_CNT);
1329 if (NEED_MIPS_GOT_RELOCS)
1330 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1331 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1332 2+(dyn[DT_PLTREL]==DT_RELA));
1333 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1334 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1335
1336 if (head != &ldso && p->relro_start != p->relro_end &&
1337 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1338 && errno != ENOSYS) {
1339 error("Error relocating %s: RELRO protection failed: %m",
1340 p->name);
1341 if (runtime) longjmp(*rtld_fail, 1);
1342 }
1343
1344 p->relocated = 1;
1345 }
1346 }
1347
1348 static void kernel_mapped_dso(struct dso *p)
1349 {
1350 size_t min_addr = -1, max_addr = 0, cnt;
1351 Phdr *ph = p->phdr;
1352 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1353 if (ph->p_type == PT_DYNAMIC) {
1354 p->dynv = laddr(p, ph->p_vaddr);
1355 } else if (ph->p_type == PT_GNU_RELRO) {
1356 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1357 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1358 } else if (ph->p_type == PT_GNU_STACK) {
1359 if (!runtime && ph->p_memsz > __default_stacksize) {
1360 __default_stacksize =
1361 ph->p_memsz < DEFAULT_STACK_MAX ?
1362 ph->p_memsz : DEFAULT_STACK_MAX;
1363 }
1364 }
1365 if (ph->p_type != PT_LOAD) continue;
1366 if (ph->p_vaddr < min_addr)
1367 min_addr = ph->p_vaddr;
1368 if (ph->p_vaddr+ph->p_memsz > max_addr)
1369 max_addr = ph->p_vaddr+ph->p_memsz;
1370 }
1371 min_addr &= -PAGE_SIZE;
1372 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1373 p->map = p->base + min_addr;
1374 p->map_len = max_addr - min_addr;
1375 p->kernel_mapped = 1;
1376 }
1377
1378 void __libc_exit_fini()
1379 {
1380 struct dso *p;
1381 size_t dyn[DYN_CNT];
1382 int self = __pthread_self()->tid;
1383
1384 /* Take both locks before setting shutting_down, so that
1385 * either lock is sufficient to read its value. The lock
1386 * order matches that in dlopen to avoid deadlock. */
1387 pthread_rwlock_wrlock(&lock);
1388 pthread_mutex_lock(&init_fini_lock);
1389 shutting_down = 1;
1390 pthread_rwlock_unlock(&lock);
1391 for (p=fini_head; p; p=p->fini_next) {
1392 while (p->ctor_visitor && p->ctor_visitor!=self)
1393 pthread_cond_wait(&ctor_cond, &init_fini_lock);
1394 if (!p->constructed) continue;
1395 decode_vec(p->dynv, dyn, DYN_CNT);
1396 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1397 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1398 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1399 while (n--) ((void (*)(void))*--fn)();
1400 }
1401 #ifndef NO_LEGACY_INITFINI
1402 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1403 fpaddr(p, dyn[DT_FINI])();
1404 #endif
1405 }
1406 }
1407
1408 static struct dso **queue_ctors(struct dso *dso)
1409 {
1410 size_t cnt, qpos, spos, i;
1411 struct dso *p, **queue, **stack;
1412
1413 if (ldd_mode) return 0;
1414
1415 /* Bound on queue size is the total number of indirect deps.
1416 * If a bfs deps list was built, we can use it. Otherwise,
1417 * bound by the total number of DSOs, which is always safe and
1418 * is reasonable we use it (for main app at startup). */
1419 if (dso->bfs_built) {
1420 for (cnt=0; dso->deps[cnt]; cnt++)
1421 dso->deps[cnt]->mark = 0;
1422 cnt++; /* self, not included in deps */
1423 } else {
1424 for (cnt=0, p=head; p; cnt++, p=p->next)
1425 p->mark = 0;
1426 }
1427 cnt++; /* termination slot */
1428 if (dso==head && cnt <= countof(builtin_ctor_queue))
1429 queue = builtin_ctor_queue;
1430 else
1431 queue = calloc(cnt, sizeof *queue);
1432
1433 if (!queue) {
1434 error("Error allocating constructor queue: %m\n");
1435 if (runtime) longjmp(*rtld_fail, 1);
1436 return 0;
1437 }
1438
1439 /* Opposite ends of the allocated buffer serve as an output queue
1440 * and a working stack. Setup initial stack with just the argument
1441 * dso and initial queue empty... */
1442 stack = queue;
1443 qpos = 0;
1444 spos = cnt;
1445 stack[--spos] = dso;
1446 dso->next_dep = 0;
1447 dso->mark = 1;
1448
1449 /* Then perform pseudo-DFS sort, but ignoring circular deps. */
1450 while (spos<cnt) {
1451 p = stack[spos++];
1452 while (p->next_dep < p->ndeps_direct) {
1453 if (p->deps[p->next_dep]->mark) {
1454 p->next_dep++;
1455 } else {
1456 stack[--spos] = p;
1457 p = p->deps[p->next_dep];
1458 p->next_dep = 0;
1459 p->mark = 1;
1460 }
1461 }
1462 queue[qpos++] = p;
1463 }
1464 queue[qpos] = 0;
1465 for (i=0; i<qpos; i++) queue[i]->mark = 0;
1466
1467 return queue;
1468 }
1469
1470 static void do_init_fini(struct dso **queue)
1471 {
1472 struct dso *p;
1473 size_t dyn[DYN_CNT], i;
1474 int self = __pthread_self()->tid;
1475
1476 pthread_mutex_lock(&init_fini_lock);
1477 for (i=0; (p=queue[i]); i++) {
1478 while ((p->ctor_visitor && p->ctor_visitor!=self) || shutting_down)
1479 pthread_cond_wait(&ctor_cond, &init_fini_lock);
1480 if (p->ctor_visitor || p->constructed)
1481 continue;
1482 p->ctor_visitor = self;
1483
1484 decode_vec(p->dynv, dyn, DYN_CNT);
1485 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1486 p->fini_next = fini_head;
1487 fini_head = p;
1488 }
1489
1490 pthread_mutex_unlock(&init_fini_lock);
1491
1492 #ifndef NO_LEGACY_INITFINI
1493 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1494 fpaddr(p, dyn[DT_INIT])();
1495 #endif
1496 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1497 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1498 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1499 while (n--) ((void (*)(void))*fn++)();
1500 }
1501
1502 pthread_mutex_lock(&init_fini_lock);
1503 p->ctor_visitor = 0;
1504 p->constructed = 1;
1505 pthread_cond_broadcast(&ctor_cond);
1506 }
1507 pthread_mutex_unlock(&init_fini_lock);
1508 }
1509
1510 void __libc_start_init(void)
1511 {
1512 do_init_fini(main_ctor_queue);
1513 if (!__malloc_replaced && main_ctor_queue != builtin_ctor_queue)
1514 free(main_ctor_queue);
1515 main_ctor_queue = 0;
1516 }
1517
1518 static void dl_debug_state(void)
1519 {
1520 }
1521
1522 weak_alias(dl_debug_state, _dl_debug_state);
1523
1524 void __init_tls(size_t *auxv)
1525 {
1526 }
1527
1528 static void update_tls_size()
1529 {
1530 libc.tls_cnt = tls_cnt;
1531 libc.tls_align = tls_align;
1532 libc.tls_size = ALIGN(
1533 (1+tls_cnt) * sizeof(void *) +
1534 tls_offset +
1535 sizeof(struct pthread) +
1536 tls_align * 2,
1537 tls_align);
1538 }
1539
1540 static void install_new_tls(void)
1541 {
1542 sigset_t set;
1543 pthread_t self = __pthread_self(), td;
1544 struct dso *dtv_provider = container_of(tls_tail, struct dso, tls);
1545 uintptr_t (*newdtv)[tls_cnt+1] = (void *)dtv_provider->new_dtv;
1546 struct dso *p;
1547 size_t i, j;
1548 size_t old_cnt = self->dtv[0];
1549
1550 __block_app_sigs(&set);
1551 __tl_lock();
1552 /* Copy existing dtv contents from all existing threads. */
1553 for (i=0, td=self; !i || td!=self; i++, td=td->next) {
1554 memcpy(newdtv+i, td->dtv,
1555 (old_cnt+1)*sizeof(uintptr_t));
1556 newdtv[i][0] = tls_cnt;
1557 }
1558 /* Install new dtls into the enlarged, uninstalled dtv copies. */
1559 for (p=head; ; p=p->next) {
1560 if (p->tls_id <= old_cnt) continue;
1561 unsigned char *mem = p->new_tls;
1562 for (j=0; j<i; j++) {
1563 unsigned char *new = mem;
1564 new += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1565 & (p->tls.align-1);
1566 memcpy(new, p->tls.image, p->tls.len);
1567 newdtv[j][p->tls_id] =
1568 (uintptr_t)new + DTP_OFFSET;
1569 mem += p->tls.size + p->tls.align;
1570 }
1571 if (p->tls_id == tls_cnt) break;
1572 }
1573
1574 /* Broadcast barrier to ensure contents of new dtv is visible
1575 * if the new dtv pointer is. The __membarrier function has a
1576 * fallback emulation using signals for kernels that lack the
1577 * feature at the syscall level. */
1578
1579 __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED, 0);
1580
1581 /* Install new dtv for each thread. */
1582 for (j=0, td=self; !j || td!=self; j++, td=td->next) {
1583 td->dtv = td->dtv_copy = newdtv[j];
1584 }
1585
1586 __tl_unlock();
1587 __restore_sigs(&set);
1588 }
1589
1590 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1591 * following stage 2 and stage 3 functions via primitive symbolic lookup
1592 * since it does not have access to their addresses to begin with. */
1593
1594 /* Stage 2 of the dynamic linker is called after relative relocations
1595 * have been processed. It can make function calls to static functions
1596 * and access string literals and static data, but cannot use extern
1597 * symbols. Its job is to perform symbolic relocations on the dynamic
1598 * linker itself, but some of the relocations performed may need to be
1599 * replaced later due to copy relocations in the main program. */
1600
1601 hidden void __dls2(unsigned char *base, size_t *sp)
1602 {
1603 size_t *auxv;
1604 for (auxv=sp+1+*sp+1; *auxv; auxv++);
1605 auxv++;
1606 if (DL_FDPIC) {
1607 void *p1 = (void *)sp[-2];
1608 void *p2 = (void *)sp[-1];
1609 if (!p1) {
1610 size_t aux[AUX_CNT];
1611 decode_vec(auxv, aux, AUX_CNT);
1612 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1613 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1614 }
1615 app_loadmap = p2 ? p1 : 0;
1616 ldso.loadmap = p2 ? p2 : p1;
1617 ldso.base = laddr(&ldso, 0);
1618 } else {
1619 ldso.base = base;
1620 }
1621 Ehdr *ehdr = (void *)ldso.base;
1622 ldso.name = ldso.shortname = "libc.so";
1623 ldso.phnum = ehdr->e_phnum;
1624 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1625 ldso.phentsize = ehdr->e_phentsize;
1626 kernel_mapped_dso(&ldso);
1627 decode_dyn(&ldso);
1628
1629 if (DL_FDPIC) makefuncdescs(&ldso);
1630
1631 /* Prepare storage for to save clobbered REL addends so they
1632 * can be reused in stage 3. There should be very few. If
1633 * something goes wrong and there are a huge number, abort
1634 * instead of risking stack overflow. */
1635 size_t dyn[DYN_CNT];
1636 decode_vec(ldso.dynv, dyn, DYN_CNT);
1637 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1638 size_t rel_size = dyn[DT_RELSZ];
1639 size_t symbolic_rel_cnt = 0;
1640 apply_addends_to = rel;
1641 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1642 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1643 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1644 size_t addends[symbolic_rel_cnt+1];
1645 saved_addends = addends;
1646
1647 head = &ldso;
1648 reloc_all(&ldso);
1649
1650 ldso.relocated = 0;
1651
1652 /* Call dynamic linker stage-2b, __dls2b, looking it up
1653 * symbolically as a barrier against moving the address
1654 * load across the above relocation processing. */
1655 struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0);
1656 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp, auxv);
1657 else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp, auxv);
1658 }
1659
1660 /* Stage 2b sets up a valid thread pointer, which requires relocations
1661 * completed in stage 2, and on which stage 3 is permitted to depend.
1662 * This is done as a separate stage, with symbolic lookup as a barrier,
1663 * so that loads of the thread pointer and &errno can be pure/const and
1664 * thereby hoistable. */
1665
1666 void __dls2b(size_t *sp, size_t *auxv)
1667 {
1668 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1669 * use during dynamic linking. If possible it will also serve as the
1670 * thread pointer at runtime. */
1671 search_vec(auxv, &__hwcap, AT_HWCAP);
1672 libc.auxv = auxv;
1673 libc.tls_size = sizeof builtin_tls;
1674 libc.tls_align = tls_align;
1675 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1676 a_crash();
1677 }
1678
1679 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1680 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp, auxv);
1681 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp, auxv);
1682 }
1683
1684 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1685 * fully functional. Its job is to load (if not already loaded) and
1686 * process dependencies and relocations for the main application and
1687 * transfer control to its entry point. */
1688
1689 void __dls3(size_t *sp, size_t *auxv)
1690 {
1691 static struct dso app, vdso;
1692 size_t aux[AUX_CNT];
1693 size_t i;
1694 char *env_preload=0;
1695 char *replace_argv0=0;
1696 size_t vdso_base;
1697 int argc = *sp;
1698 char **argv = (void *)(sp+1);
1699 char **argv_orig = argv;
1700 char **envp = argv+argc+1;
1701
1702 /* Find aux vector just past environ[] and use it to initialize
1703 * global data that may be needed before we can make syscalls. */
1704 __environ = envp;
1705 decode_vec(auxv, aux, AUX_CNT);
1706 search_vec(auxv, &__sysinfo, AT_SYSINFO);
1707 __pthread_self()->sysinfo = __sysinfo;
1708 libc.page_size = aux[AT_PAGESZ];
1709 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1710 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1711
1712 /* Only trust user/env if kernel says we're not suid/sgid */
1713 if (!libc.secure) {
1714 env_path = getenv("LD_LIBRARY_PATH");
1715 env_preload = getenv("LD_PRELOAD");
1716 }
1717
1718 /* If the main program was already loaded by the kernel,
1719 * AT_PHDR will point to some location other than the dynamic
1720 * linker's program headers. */
1721 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1722 size_t interp_off = 0;
1723 size_t tls_image = 0;
1724 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1725 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1726 app.phnum = aux[AT_PHNUM];
1727 app.phentsize = aux[AT_PHENT];
1728 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1729 if (phdr->p_type == PT_PHDR)
1730 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1731 else if (phdr->p_type == PT_INTERP)
1732 interp_off = (size_t)phdr->p_vaddr;
1733 else if (phdr->p_type == PT_TLS) {
1734 tls_image = phdr->p_vaddr;
1735 app.tls.len = phdr->p_filesz;
1736 app.tls.size = phdr->p_memsz;
1737 app.tls.align = phdr->p_align;
1738 }
1739 }
1740 if (DL_FDPIC) app.loadmap = app_loadmap;
1741 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1742 if (interp_off) ldso.name = laddr(&app, interp_off);
1743 if ((aux[0] & (1UL<<AT_EXECFN))
1744 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1745 app.name = (char *)aux[AT_EXECFN];
1746 else
1747 app.name = argv[0];
1748 kernel_mapped_dso(&app);
1749 } else {
1750 int fd;
1751 char *ldname = argv[0];
1752 size_t l = strlen(ldname);
1753 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1754 argv++;
1755 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1756 char *opt = argv[0]+2;
1757 *argv++ = (void *)-1;
1758 if (!*opt) {
1759 break;
1760 } else if (!memcmp(opt, "list", 5)) {
1761 ldd_mode = 1;
1762 } else if (!memcmp(opt, "library-path", 12)) {
1763 if (opt[12]=='=') env_path = opt+13;
1764 else if (opt[12]) *argv = 0;
1765 else if (*argv) env_path = *argv++;
1766 } else if (!memcmp(opt, "preload", 7)) {
1767 if (opt[7]=='=') env_preload = opt+8;
1768 else if (opt[7]) *argv = 0;
1769 else if (*argv) env_preload = *argv++;
1770 } else if (!memcmp(opt, "argv0", 5)) {
1771 if (opt[5]=='=') replace_argv0 = opt+6;
1772 else if (opt[5]) *argv = 0;
1773 else if (*argv) replace_argv0 = *argv++;
1774 } else {
1775 argv[0] = 0;
1776 }
1777 }
1778 argv[-1] = (void *)(argc - (argv-argv_orig));
1779 if (!argv[0]) {
1780 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1781 "Version %s\n"
1782 "Dynamic Program Loader\n"
1783 "Usage: %s [options] [--] pathname%s\n",
1784 __libc_version, ldname,
1785 ldd_mode ? "" : " [args]");
1786 _exit(1);
1787 }
1788 fd = open(argv[0], O_RDONLY);
1789 if (fd < 0) {
1790 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1791 _exit(1);
1792 }
1793 Ehdr *ehdr = (void *)map_library(fd, &app);
1794 if (!ehdr) {
1795 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1796 _exit(1);
1797 }
1798 close(fd);
1799 ldso.name = ldname;
1800 app.name = argv[0];
1801 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1802 /* Find the name that would have been used for the dynamic
1803 * linker had ldd not taken its place. */
1804 if (ldd_mode) {
1805 for (i=0; i<app.phnum; i++) {
1806 if (app.phdr[i].p_type == PT_INTERP)
1807 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1808 }
1809 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1810 }
1811 }
1812 if (app.tls.size) {
1813 libc.tls_head = tls_tail = &app.tls;
1814 app.tls_id = tls_cnt = 1;
1815 #ifdef TLS_ABOVE_TP
1816 app.tls.offset = GAP_ABOVE_TP;
1817 app.tls.offset += (-GAP_ABOVE_TP + (uintptr_t)app.tls.image)
1818 & (app.tls.align-1);
1819 tls_offset = app.tls.offset + app.tls.size;
1820 #else
1821 tls_offset = app.tls.offset = app.tls.size
1822 + ( -((uintptr_t)app.tls.image + app.tls.size)
1823 & (app.tls.align-1) );
1824 #endif
1825 tls_align = MAXP2(tls_align, app.tls.align);
1826 }
1827 decode_dyn(&app);
1828 if (DL_FDPIC) {
1829 makefuncdescs(&app);
1830 if (!app.loadmap) {
1831 app.loadmap = (void *)&app_dummy_loadmap;
1832 app.loadmap->nsegs = 1;
1833 app.loadmap->segs[0].addr = (size_t)app.map;
1834 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1835 - (size_t)app.base;
1836 app.loadmap->segs[0].p_memsz = app.map_len;
1837 }
1838 argv[-3] = (void *)app.loadmap;
1839 }
1840
1841 /* Initial dso chain consists only of the app. */
1842 head = tail = syms_tail = &app;
1843
1844 /* Donate unused parts of app and library mapping to malloc */
1845 reclaim_gaps(&app);
1846 reclaim_gaps(&ldso);
1847
1848 /* Load preload/needed libraries, add symbols to global namespace. */
1849 ldso.deps = (struct dso **)no_deps;
1850 if (env_preload) load_preload(env_preload);
1851 load_deps(&app);
1852 for (struct dso *p=head; p; p=p->next)
1853 add_syms(p);
1854
1855 /* Attach to vdso, if provided by the kernel, last so that it does
1856 * not become part of the global namespace. */
1857 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1858 Ehdr *ehdr = (void *)vdso_base;
1859 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1860 vdso.phnum = ehdr->e_phnum;
1861 vdso.phentsize = ehdr->e_phentsize;
1862 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1863 if (phdr->p_type == PT_DYNAMIC)
1864 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1865 if (phdr->p_type == PT_LOAD)
1866 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1867 }
1868 vdso.name = "";
1869 vdso.shortname = "linux-gate.so.1";
1870 vdso.relocated = 1;
1871 vdso.deps = (struct dso **)no_deps;
1872 decode_dyn(&vdso);
1873 vdso.prev = tail;
1874 tail->next = &vdso;
1875 tail = &vdso;
1876 }
1877
1878 for (i=0; app.dynv[i]; i+=2) {
1879 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1880 app.dynv[i+1] = (size_t)&debug;
1881 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1882 size_t *ptr = (size_t *) app.dynv[i+1];
1883 *ptr = (size_t)&debug;
1884 }
1885 }
1886
1887 /* This must be done before final relocations, since it calls
1888 * malloc, which may be provided by the application. Calling any
1889 * application code prior to the jump to its entry point is not
1890 * valid in our model and does not work with FDPIC, where there
1891 * are additional relocation-like fixups that only the entry point
1892 * code can see to perform. */
1893 main_ctor_queue = queue_ctors(&app);
1894
1895 /* Initial TLS must also be allocated before final relocations
1896 * might result in calloc being a call to application code. */
1897 update_tls_size();
1898 void *initial_tls = builtin_tls;
1899 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1900 initial_tls = calloc(libc.tls_size, 1);
1901 if (!initial_tls) {
1902 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1903 argv[0], libc.tls_size);
1904 _exit(127);
1905 }
1906 }
1907 static_tls_cnt = tls_cnt;
1908
1909 /* The main program must be relocated LAST since it may contain
1910 * copy relocations which depend on libraries' relocations. */
1911 reloc_all(app.next);
1912 reloc_all(&app);
1913
1914 /* Actual copying to new TLS needs to happen after relocations,
1915 * since the TLS images might have contained relocated addresses. */
1916 if (initial_tls != builtin_tls) {
1917 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1918 a_crash();
1919 }
1920 } else {
1921 size_t tmp_tls_size = libc.tls_size;
1922 pthread_t self = __pthread_self();
1923 /* Temporarily set the tls size to the full size of
1924 * builtin_tls so that __copy_tls will use the same layout
1925 * as it did for before. Then check, just to be safe. */
1926 libc.tls_size = sizeof builtin_tls;
1927 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1928 libc.tls_size = tmp_tls_size;
1929 }
1930
1931 if (ldso_fail) _exit(127);
1932 if (ldd_mode) _exit(0);
1933
1934 /* Determine if malloc was interposed by a replacement implementation
1935 * so that calloc and the memalign family can harden against the
1936 * possibility of incomplete replacement. */
1937 if (find_sym(head, "malloc", 1).dso != &ldso)
1938 __malloc_replaced = 1;
1939
1940 /* Switch to runtime mode: any further failures in the dynamic
1941 * linker are a reportable failure rather than a fatal startup
1942 * error. */
1943 runtime = 1;
1944
1945 debug.ver = 1;
1946 debug.bp = dl_debug_state;
1947 debug.head = head;
1948 debug.base = ldso.base;
1949 debug.state = 0;
1950 _dl_debug_state();
1951
1952 if (replace_argv0) argv[0] = replace_argv0;
1953
1954 errno = 0;
1955
1956 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1957 for(;;);
1958 }
1959
1960 static void prepare_lazy(struct dso *p)
1961 {
1962 size_t dyn[DYN_CNT], n, flags1=0;
1963 decode_vec(p->dynv, dyn, DYN_CNT);
1964 search_vec(p->dynv, &flags1, DT_FLAGS_1);
1965 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1966 return;
1967 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1968 if (NEED_MIPS_GOT_RELOCS) {
1969 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1970 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1971 n += i-j;
1972 }
1973 p->lazy = calloc(n, 3*sizeof(size_t));
1974 if (!p->lazy) {
1975 error("Error preparing lazy relocation for %s: %m", p->name);
1976 longjmp(*rtld_fail, 1);
1977 }
1978 p->lazy_next = lazy_head;
1979 lazy_head = p;
1980 }
1981
1982 void *dlopen(const char *file, int mode)
1983 {
1984 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1985 struct tls_module *orig_tls_tail;
1986 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1987 size_t i;
1988 int cs;
1989 jmp_buf jb;
1990 struct dso **volatile ctor_queue = 0;
1991
1992 if (!file) return head;
1993
1994 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1995 pthread_rwlock_wrlock(&lock);
1996 __inhibit_ptc();
1997
1998 p = 0;
1999 if (shutting_down) {
2000 error("Cannot dlopen while program is exiting.");
2001 goto end;
2002 }
2003 orig_tls_tail = tls_tail;
2004 orig_tls_cnt = tls_cnt;
2005 orig_tls_offset = tls_offset;
2006 orig_tls_align = tls_align;
2007 orig_lazy_head = lazy_head;
2008 orig_syms_tail = syms_tail;
2009 orig_tail = tail;
2010 noload = mode & RTLD_NOLOAD;
2011
2012 rtld_fail = &jb;
2013 if (setjmp(*rtld_fail)) {
2014 /* Clean up anything new that was (partially) loaded */
2015 revert_syms(orig_syms_tail);
2016 for (p=orig_tail->next; p; p=next) {
2017 next = p->next;
2018 while (p->td_index) {
2019 void *tmp = p->td_index->next;
2020 free(p->td_index);
2021 p->td_index = tmp;
2022 }
2023 free(p->funcdescs);
2024 if (p->rpath != p->rpath_orig)
2025 free(p->rpath);
2026 free(p->deps);
2027 unmap_library(p);
2028 free(p);
2029 }
2030 free(ctor_queue);
2031 ctor_queue = 0;
2032 if (!orig_tls_tail) libc.tls_head = 0;
2033 tls_tail = orig_tls_tail;
2034 if (tls_tail) tls_tail->next = 0;
2035 tls_cnt = orig_tls_cnt;
2036 tls_offset = orig_tls_offset;
2037 tls_align = orig_tls_align;
2038 lazy_head = orig_lazy_head;
2039 tail = orig_tail;
2040 tail->next = 0;
2041 p = 0;
2042 goto end;
2043 } else p = load_library(file, head);
2044
2045 if (!p) {
2046 error(noload ?
2047 "Library %s is not already loaded" :
2048 "Error loading shared library %s: %m",
2049 file);
2050 goto end;
2051 }
2052
2053 /* First load handling */
2054 load_deps(p);
2055 extend_bfs_deps(p);
2056 pthread_mutex_lock(&init_fini_lock);
2057 if (!p->constructed) ctor_queue = queue_ctors(p);
2058 pthread_mutex_unlock(&init_fini_lock);
2059 if (!p->relocated && (mode & RTLD_LAZY)) {
2060 prepare_lazy(p);
2061 for (i=0; p->deps[i]; i++)
2062 if (!p->deps[i]->relocated)
2063 prepare_lazy(p->deps[i]);
2064 }
2065 if (!p->relocated || (mode & RTLD_GLOBAL)) {
2066 /* Make new symbols global, at least temporarily, so we can do
2067 * relocations. If not RTLD_GLOBAL, this is reverted below. */
2068 add_syms(p);
2069 for (i=0; p->deps[i]; i++)
2070 add_syms(p->deps[i]);
2071 }
2072 if (!p->relocated) {
2073 reloc_all(p);
2074 }
2075
2076 /* If RTLD_GLOBAL was not specified, undo any new additions
2077 * to the global symbol table. This is a nop if the library was
2078 * previously loaded and already global. */
2079 if (!(mode & RTLD_GLOBAL))
2080 revert_syms(orig_syms_tail);
2081
2082 /* Processing of deferred lazy relocations must not happen until
2083 * the new libraries are committed; otherwise we could end up with
2084 * relocations resolved to symbol definitions that get removed. */
2085 redo_lazy_relocs();
2086
2087 update_tls_size();
2088 if (tls_cnt != orig_tls_cnt)
2089 install_new_tls();
2090 _dl_debug_state();
2091 orig_tail = tail;
2092 end:
2093 __release_ptc();
2094 if (p) gencnt++;
2095 pthread_rwlock_unlock(&lock);
2096 if (ctor_queue) {
2097 do_init_fini(ctor_queue);
2098 free(ctor_queue);
2099 }
2100 pthread_setcancelstate(cs, 0);
2101 return p;
2102 }
2103
2104 hidden int __dl_invalid_handle(void *h)
2105 {
2106 struct dso *p;
2107 for (p=head; p; p=p->next) if (h==p) return 0;
2108 error("Invalid library handle %p", (void *)h);
2109 return 1;
2110 }
2111
2112 static void *addr2dso(size_t a)
2113 {
2114 struct dso *p;
2115 size_t i;
2116 if (DL_FDPIC) for (p=head; p; p=p->next) {
2117 i = count_syms(p);
2118 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
2119 return p;
2120 }
2121 for (p=head; p; p=p->next) {
2122 if (DL_FDPIC && p->loadmap) {
2123 for (i=0; i<p->loadmap->nsegs; i++) {
2124 if (a-p->loadmap->segs[i].p_vaddr
2125 < p->loadmap->segs[i].p_memsz)
2126 return p;
2127 }
2128 } else {
2129 Phdr *ph = p->phdr;
2130 size_t phcnt = p->phnum;
2131 size_t entsz = p->phentsize;
2132 size_t base = (size_t)p->base;
2133 for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
2134 if (ph->p_type != PT_LOAD) continue;
2135 if (a-base-ph->p_vaddr < ph->p_memsz)
2136 return p;
2137 }
2138 if (a-(size_t)p->map < p->map_len)
2139 return 0;
2140 }
2141 }
2142 return 0;
2143 }
2144
2145 static void *do_dlsym(struct dso *p, const char *s, void *ra)
2146 {
2147 int use_deps = 0;
2148 if (p == head || p == RTLD_DEFAULT) {
2149 p = head;
2150 } else if (p == RTLD_NEXT) {
2151 p = addr2dso((size_t)ra);
2152 if (!p) p=head;
2153 p = p->next;
2154 } else if (__dl_invalid_handle(p)) {
2155 return 0;
2156 } else
2157 use_deps = 1;
2158 struct symdef def = find_sym2(p, s, 0, use_deps);
2159 if (!def.sym) {
2160 error("Symbol not found: %s", s);
2161 return 0;
2162 }
2163 if ((def.sym->st_info&0xf) == STT_TLS)
2164 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
2165 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
2166 return def.dso->funcdescs + (def.sym - def.dso->syms);
2167 return laddr(def.dso, def.sym->st_value);
2168 }
2169
2170 int dladdr(const void *addr_arg, Dl_info *info)
2171 {
2172 size_t addr = (size_t)addr_arg;
2173 struct dso *p;
2174 Sym *sym, *bestsym;
2175 uint32_t nsym;
2176 char *strings;
2177 size_t best = 0;
2178 size_t besterr = -1;
2179
2180 pthread_rwlock_rdlock(&lock);
2181 p = addr2dso(addr);
2182 pthread_rwlock_unlock(&lock);
2183
2184 if (!p) return 0;
2185
2186 sym = p->syms;
2187 strings = p->strings;
2188 nsym = count_syms(p);
2189
2190 if (DL_FDPIC) {
2191 size_t idx = (addr-(size_t)p->funcdescs)
2192 / sizeof(*p->funcdescs);
2193 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
2194 best = (size_t)(p->funcdescs + idx);
2195 bestsym = sym + idx;
2196 besterr = 0;
2197 }
2198 }
2199
2200 if (!best) for (; nsym; nsym--, sym++) {
2201 if (sym->st_value
2202 && (1<<(sym->st_info&0xf) & OK_TYPES)
2203 && (1<<(sym->st_info>>4) & OK_BINDS)) {
2204 size_t symaddr = (size_t)laddr(p, sym->st_value);
2205 if (symaddr > addr || symaddr <= best)
2206 continue;
2207 best = symaddr;
2208 bestsym = sym;
2209 besterr = addr - symaddr;
2210 if (addr == symaddr)
2211 break;
2212 }
2213 }
2214
2215 if (best && besterr > bestsym->st_size-1) {
2216 best = 0;
2217 bestsym = 0;
2218 }
2219
2220 info->dli_fname = p->name;
2221 info->dli_fbase = p->map;
2222
2223 if (!best) {
2224 info->dli_sname = 0;
2225 info->dli_saddr = 0;
2226 return 1;
2227 }
2228
2229 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2230 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2231 info->dli_sname = strings + bestsym->st_name;
2232 info->dli_saddr = (void *)best;
2233
2234 return 1;
2235 }
2236
2237 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2238 {
2239 void *res;
2240 pthread_rwlock_rdlock(&lock);
2241 res = do_dlsym(p, s, ra);
2242 pthread_rwlock_unlock(&lock);
2243 return res;
2244 }
2245
2246 hidden void *__dlsym_redir_time64(void *restrict p, const char *restrict s, void *restrict ra)
2247 {
2248 #if _REDIR_TIME64
2249 const char *suffix, *suffix2 = "";
2250 char redir[36];
2251
2252 /* Map the symbol name to a time64 version of itself according to the
2253 * pattern used for naming the redirected time64 symbols. */
2254 size_t l = strnlen(s, sizeof redir);
2255 if (l<4 || l==sizeof redir) goto no_redir;
2256 if (s[l-2]=='_' && s[l-1]=='r') {
2257 l -= 2;
2258 suffix2 = s+l;
2259 }
2260 if (l<4) goto no_redir;
2261 if (!strcmp(s+l-4, "time")) suffix = "64";
2262 else suffix = "_time64";
2263
2264 /* Use the presence of the remapped symbol name in libc to determine
2265 * whether it's one that requires time64 redirection; replace if so. */
2266 snprintf(redir, sizeof redir, "__%.*s%s%s", (int)l, s, suffix, suffix2);
2267 if (find_sym(&ldso, redir, 1).sym) s = redir;
2268 no_redir:
2269 #endif
2270 return __dlsym(p, s, ra);
2271 }
2272
2273 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2274 {
2275 struct dso *current;
2276 struct dl_phdr_info info;
2277 int ret = 0;
2278 for(current = head; current;) {
2279 info.dlpi_addr = (uintptr_t)current->base;
2280 info.dlpi_name = current->name;
2281 info.dlpi_phdr = current->phdr;
2282 info.dlpi_phnum = current->phnum;
2283 info.dlpi_adds = gencnt;
2284 info.dlpi_subs = 0;
2285 info.dlpi_tls_modid = current->tls_id;
2286 info.dlpi_tls_data = current->tls.image;
2287
2288 ret = (callback)(&info, sizeof (info), data);
2289
2290 if (ret != 0) break;
2291
2292 pthread_rwlock_rdlock(&lock);
2293 current = current->next;
2294 pthread_rwlock_unlock(&lock);
2295 }
2296 return ret;
2297 }
2298
2299 static void error(const char *fmt, ...)
2300 {
2301 va_list ap;
2302 va_start(ap, fmt);
2303 if (!runtime) {
2304 vdprintf(2, fmt, ap);
2305 dprintf(2, "\n");
2306 ldso_fail = 1;
2307 va_end(ap);
2308 return;
2309 }
2310 __dl_vseterr(fmt, ap);
2311 va_end(ap);
2312 }
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