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drop use of getdelim/stdio in dynamic linker
[musl.git] / ldso / dynlink.c
blob502e52c51a852436e6cd57e247b859aba4a4c202
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 "libc.h"
24 #include "dynlink.h"
25
26 static void error(const char *, ...);
27
28 #define MAXP2(a,b) (-(-(a)&-(b)))
29 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
30
31 #define container_of(p,t,m) ((t*)((char *)(p)-offsetof(t,m)))
32 #define countof(a) ((sizeof (a))/(sizeof (a)[0]))
33
34 struct debug {
35 int ver;
36 void *head;
37 void (*bp)(void);
38 int state;
39 void *base;
40 };
41
42 struct td_index {
43 size_t args[2];
44 struct td_index *next;
45 };
46
47 struct dso {
48 #if DL_FDPIC
49 struct fdpic_loadmap *loadmap;
50 #else
51 unsigned char *base;
52 #endif
53 char *name;
54 size_t *dynv;
55 struct dso *next, *prev;
56
57 Phdr *phdr;
58 int phnum;
59 size_t phentsize;
60 Sym *syms;
61 Elf_Symndx *hashtab;
62 uint32_t *ghashtab;
63 int16_t *versym;
64 char *strings;
65 struct dso *syms_next, *lazy_next;
66 size_t *lazy, lazy_cnt;
67 unsigned char *map;
68 size_t map_len;
69 dev_t dev;
70 ino_t ino;
71 char relocated;
72 char constructed;
73 char kernel_mapped;
74 char mark;
75 char bfs_built;
76 char runtime_loaded;
77 struct dso **deps, *needed_by;
78 size_t ndeps_direct;
79 size_t next_dep;
80 pthread_t ctor_visitor;
81 char *rpath_orig, *rpath;
82 struct tls_module tls;
83 size_t tls_id;
84 size_t relro_start, relro_end;
85 uintptr_t *new_dtv;
86 unsigned char *new_tls;
87 struct td_index *td_index;
88 struct dso *fini_next;
89 char *shortname;
90 #if DL_FDPIC
91 unsigned char *base;
92 #else
93 struct fdpic_loadmap *loadmap;
94 #endif
95 struct funcdesc {
96 void *addr;
97 size_t *got;
98 } *funcdescs;
99 size_t *got;
100 char buf[];
101 };
102
103 struct symdef {
104 Sym *sym;
105 struct dso *dso;
106 };
107
108 typedef void (*stage3_func)(size_t *, size_t *);
109
110 static struct builtin_tls {
111 char c;
112 struct pthread pt;
113 void *space[16];
114 } builtin_tls[1];
115 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
116
117 #define ADDEND_LIMIT 4096
118 static size_t *saved_addends, *apply_addends_to;
119
120 static struct dso ldso;
121 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
122 static char *env_path, *sys_path;
123 static unsigned long long gencnt;
124 static int runtime;
125 static int ldd_mode;
126 static int ldso_fail;
127 static int noload;
128 static int shutting_down;
129 static jmp_buf *rtld_fail;
130 static pthread_rwlock_t lock;
131 static struct debug debug;
132 static struct tls_module *tls_tail;
133 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
134 static size_t static_tls_cnt;
135 static pthread_mutex_t init_fini_lock;
136 static pthread_cond_t ctor_cond;
137 static struct dso *builtin_deps[2];
138 static struct dso *const no_deps[1];
139 static struct dso *builtin_ctor_queue[4];
140 static struct dso **main_ctor_queue;
141 static struct fdpic_loadmap *app_loadmap;
142 static struct fdpic_dummy_loadmap app_dummy_loadmap;
143
144 struct debug *_dl_debug_addr = &debug;
145
146 extern hidden int __malloc_replaced;
147
148 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
149
150 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
151
152 weak_alias(__init_array_start, __init_array_end);
153 weak_alias(__fini_array_start, __fini_array_end);
154
155 static int dl_strcmp(const char *l, const char *r)
156 {
157 for (; *l==*r && *l; l++, r++);
158 return *(unsigned char *)l - *(unsigned char *)r;
159 }
160 #define strcmp(l,r) dl_strcmp(l,r)
161
162 /* Compute load address for a virtual address in a given dso. */
163 #if DL_FDPIC
164 static void *laddr(const struct dso *p, size_t v)
165 {
166 size_t j=0;
167 if (!p->loadmap) return p->base + v;
168 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
169 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
170 }
171 static void *laddr_pg(const struct dso *p, size_t v)
172 {
173 size_t j=0;
174 size_t pgsz = PAGE_SIZE;
175 if (!p->loadmap) return p->base + v;
176 for (j=0; ; j++) {
177 size_t a = p->loadmap->segs[j].p_vaddr;
178 size_t b = a + p->loadmap->segs[j].p_memsz;
179 a &= -pgsz;
180 b += pgsz-1;
181 b &= -pgsz;
182 if (v-a<b-a) break;
183 }
184 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
185 }
186 static void (*fdbarrier(void *p))()
187 {
188 void (*fd)();
189 __asm__("" : "=r"(fd) : "0"(p));
190 return fd;
191 }
192 #define fpaddr(p, v) fdbarrier((&(struct funcdesc){ \
193 laddr(p, v), (p)->got }))
194 #else
195 #define laddr(p, v) (void *)((p)->base + (v))
196 #define laddr_pg(p, v) laddr(p, v)
197 #define fpaddr(p, v) ((void (*)())laddr(p, v))
198 #endif
199
200 static void decode_vec(size_t *v, size_t *a, size_t cnt)
201 {
202 size_t i;
203 for (i=0; i<cnt; i++) a[i] = 0;
204 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
205 a[0] |= 1UL<<v[0];
206 a[v[0]] = v[1];
207 }
208 }
209
210 static int search_vec(size_t *v, size_t *r, size_t key)
211 {
212 for (; v[0]!=key; v+=2)
213 if (!v[0]) return 0;
214 *r = v[1];
215 return 1;
216 }
217
218 static uint32_t sysv_hash(const char *s0)
219 {
220 const unsigned char *s = (void *)s0;
221 uint_fast32_t h = 0;
222 while (*s) {
223 h = 16*h + *s++;
224 h ^= h>>24 & 0xf0;
225 }
226 return h & 0xfffffff;
227 }
228
229 static uint32_t gnu_hash(const char *s0)
230 {
231 const unsigned char *s = (void *)s0;
232 uint_fast32_t h = 5381;
233 for (; *s; s++)
234 h += h*32 + *s;
235 return h;
236 }
237
238 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
239 {
240 size_t i;
241 Sym *syms = dso->syms;
242 Elf_Symndx *hashtab = dso->hashtab;
243 char *strings = dso->strings;
244 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
245 if ((!dso->versym || dso->versym[i] >= 0)
246 && (!strcmp(s, strings+syms[i].st_name)))
247 return syms+i;
248 }
249 return 0;
250 }
251
252 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
253 {
254 uint32_t nbuckets = hashtab[0];
255 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
256 uint32_t i = buckets[h1 % nbuckets];
257
258 if (!i) return 0;
259
260 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
261
262 for (h1 |= 1; ; i++) {
263 uint32_t h2 = *hashval++;
264 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
265 && !strcmp(s, dso->strings + dso->syms[i].st_name))
266 return dso->syms+i;
267 if (h2 & 1) break;
268 }
269
270 return 0;
271 }
272
273 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
274 {
275 const size_t *bloomwords = (const void *)(hashtab+4);
276 size_t f = bloomwords[fofs & (hashtab[2]-1)];
277 if (!(f & fmask)) return 0;
278
279 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
280 if (!(f & 1)) return 0;
281
282 return gnu_lookup(h1, hashtab, dso, s);
283 }
284
285 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
286 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
287
288 #ifndef ARCH_SYM_REJECT_UND
289 #define ARCH_SYM_REJECT_UND(s) 0
290 #endif
291
292 #if defined(__GNUC__)
293 __attribute__((always_inline))
294 #endif
295 static inline struct symdef find_sym2(struct dso *dso, const char *s, int need_def, int use_deps)
296 {
297 uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
298 size_t ghm = 1ul << gh % (8*sizeof(size_t));
299 struct symdef def = {0};
300 struct dso **deps = use_deps ? dso->deps : 0;
301 for (; dso; dso=use_deps ? *deps++ : dso->syms_next) {
302 Sym *sym;
303 if ((ght = dso->ghashtab)) {
304 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
305 } else {
306 if (!h) h = sysv_hash(s);
307 sym = sysv_lookup(s, h, dso);
308 }
309 if (!sym) continue;
310 if (!sym->st_shndx)
311 if (need_def || (sym->st_info&0xf) == STT_TLS
312 || ARCH_SYM_REJECT_UND(sym))
313 continue;
314 if (!sym->st_value)
315 if ((sym->st_info&0xf) != STT_TLS)
316 continue;
317 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
318 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
319 def.sym = sym;
320 def.dso = dso;
321 break;
322 }
323 return def;
324 }
325
326 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
327 {
328 return find_sym2(dso, s, need_def, 0);
329 }
330
331 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
332 {
333 unsigned char *base = dso->base;
334 Sym *syms = dso->syms;
335 char *strings = dso->strings;
336 Sym *sym;
337 const char *name;
338 void *ctx;
339 int type;
340 int sym_index;
341 struct symdef def;
342 size_t *reloc_addr;
343 size_t sym_val;
344 size_t tls_val;
345 size_t addend;
346 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
347
348 if (dso == &ldso) {
349 /* Only ldso's REL table needs addend saving/reuse. */
350 if (rel == apply_addends_to)
351 reuse_addends = 1;
352 skip_relative = 1;
353 }
354
355 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
356 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
357 type = R_TYPE(rel[1]);
358 if (type == REL_NONE) continue;
359 reloc_addr = laddr(dso, rel[0]);
360
361 if (stride > 2) {
362 addend = rel[2];
363 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
364 addend = 0;
365 } else if (reuse_addends) {
366 /* Save original addend in stage 2 where the dso
367 * chain consists of just ldso; otherwise read back
368 * saved addend since the inline one was clobbered. */
369 if (head==&ldso)
370 saved_addends[save_slot] = *reloc_addr;
371 addend = saved_addends[save_slot++];
372 } else {
373 addend = *reloc_addr;
374 }
375
376 sym_index = R_SYM(rel[1]);
377 if (sym_index) {
378 sym = syms + sym_index;
379 name = strings + sym->st_name;
380 ctx = type==REL_COPY ? head->syms_next : head;
381 def = (sym->st_info>>4) == STB_LOCAL
382 ? (struct symdef){ .dso = dso, .sym = sym }
383 : find_sym(ctx, name, type==REL_PLT);
384 if (!def.sym && (sym->st_shndx != SHN_UNDEF
385 || sym->st_info>>4 != STB_WEAK)) {
386 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
387 dso->lazy[3*dso->lazy_cnt+0] = rel[0];
388 dso->lazy[3*dso->lazy_cnt+1] = rel[1];
389 dso->lazy[3*dso->lazy_cnt+2] = addend;
390 dso->lazy_cnt++;
391 continue;
392 }
393 error("Error relocating %s: %s: symbol not found",
394 dso->name, name);
395 if (runtime) longjmp(*rtld_fail, 1);
396 continue;
397 }
398 } else {
399 sym = 0;
400 def.sym = 0;
401 def.dso = dso;
402 }
403
404 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
405 tls_val = def.sym ? def.sym->st_value : 0;
406
407 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
408 && def.dso->tls_id > static_tls_cnt) {
409 error("Error relocating %s: %s: initial-exec TLS "
410 "resolves to dynamic definition in %s",
411 dso->name, name, def.dso->name);
412 longjmp(*rtld_fail, 1);
413 }
414
415 switch(type) {
416 case REL_OFFSET:
417 addend -= (size_t)reloc_addr;
418 case REL_SYMBOLIC:
419 case REL_GOT:
420 case REL_PLT:
421 *reloc_addr = sym_val + addend;
422 break;
423 case REL_USYMBOLIC:
424 memcpy(reloc_addr, &(size_t){sym_val + addend}, sizeof(size_t));
425 break;
426 case REL_RELATIVE:
427 *reloc_addr = (size_t)base + addend;
428 break;
429 case REL_SYM_OR_REL:
430 if (sym) *reloc_addr = sym_val + addend;
431 else *reloc_addr = (size_t)base + addend;
432 break;
433 case REL_COPY:
434 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
435 break;
436 case REL_OFFSET32:
437 *(uint32_t *)reloc_addr = sym_val + addend
438 - (size_t)reloc_addr;
439 break;
440 case REL_FUNCDESC:
441 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
442 + (def.sym - def.dso->syms)) : 0;
443 break;
444 case REL_FUNCDESC_VAL:
445 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
446 else *reloc_addr = sym_val;
447 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
448 break;
449 case REL_DTPMOD:
450 *reloc_addr = def.dso->tls_id;
451 break;
452 case REL_DTPOFF:
453 *reloc_addr = tls_val + addend - DTP_OFFSET;
454 break;
455 #ifdef TLS_ABOVE_TP
456 case REL_TPOFF:
457 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
458 break;
459 #else
460 case REL_TPOFF:
461 *reloc_addr = tls_val - def.dso->tls.offset + addend;
462 break;
463 case REL_TPOFF_NEG:
464 *reloc_addr = def.dso->tls.offset - tls_val + addend;
465 break;
466 #endif
467 case REL_TLSDESC:
468 if (stride<3) addend = reloc_addr[1];
469 if (def.dso->tls_id > static_tls_cnt) {
470 struct td_index *new = malloc(sizeof *new);
471 if (!new) {
472 error(
473 "Error relocating %s: cannot allocate TLSDESC for %s",
474 dso->name, sym ? name : "(local)" );
475 longjmp(*rtld_fail, 1);
476 }
477 new->next = dso->td_index;
478 dso->td_index = new;
479 new->args[0] = def.dso->tls_id;
480 new->args[1] = tls_val + addend - DTP_OFFSET;
481 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
482 reloc_addr[1] = (size_t)new;
483 } else {
484 reloc_addr[0] = (size_t)__tlsdesc_static;
485 #ifdef TLS_ABOVE_TP
486 reloc_addr[1] = tls_val + def.dso->tls.offset
487 + TPOFF_K + addend;
488 #else
489 reloc_addr[1] = tls_val - def.dso->tls.offset
490 + addend;
491 #endif
492 }
493 #ifdef TLSDESC_BACKWARDS
494 /* Some archs (32-bit ARM at least) invert the order of
495 * the descriptor members. Fix them up here. */
496 size_t tmp = reloc_addr[0];
497 reloc_addr[0] = reloc_addr[1];
498 reloc_addr[1] = tmp;
499 #endif
500 break;
501 default:
502 error("Error relocating %s: unsupported relocation type %d",
503 dso->name, type);
504 if (runtime) longjmp(*rtld_fail, 1);
505 continue;
506 }
507 }
508 }
509
510 static void redo_lazy_relocs()
511 {
512 struct dso *p = lazy_head, *next;
513 lazy_head = 0;
514 for (; p; p=next) {
515 next = p->lazy_next;
516 size_t size = p->lazy_cnt*3*sizeof(size_t);
517 p->lazy_cnt = 0;
518 do_relocs(p, p->lazy, size, 3);
519 if (p->lazy_cnt) {
520 p->lazy_next = lazy_head;
521 lazy_head = p;
522 } else {
523 free(p->lazy);
524 p->lazy = 0;
525 p->lazy_next = 0;
526 }
527 }
528 }
529
530 /* A huge hack: to make up for the wastefulness of shared libraries
531 * needing at least a page of dirty memory even if they have no global
532 * data, we reclaim the gaps at the beginning and end of writable maps
533 * and "donate" them to the heap. */
534
535 static void reclaim(struct dso *dso, size_t start, size_t end)
536 {
537 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
538 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
539 if (start >= end) return;
540 char *base = laddr_pg(dso, start);
541 __malloc_donate(base, base+(end-start));
542 }
543
544 static void reclaim_gaps(struct dso *dso)
545 {
546 Phdr *ph = dso->phdr;
547 size_t phcnt = dso->phnum;
548
549 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
550 if (ph->p_type!=PT_LOAD) continue;
551 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
552 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
553 reclaim(dso, ph->p_vaddr+ph->p_memsz,
554 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
555 }
556 }
557
558 static ssize_t read_loop(int fd, void *p, size_t n)
559 {
560 for (size_t i=0; i<n; ) {
561 ssize_t l = read(fd, (char *)p+i, n-i);
562 if (l<0) {
563 if (errno==EINTR) continue;
564 else return -1;
565 }
566 if (l==0) return i;
567 i += l;
568 }
569 return n;
570 }
571
572 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
573 {
574 static int no_map_fixed;
575 char *q;
576 if (!no_map_fixed) {
577 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
578 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
579 return q;
580 no_map_fixed = 1;
581 }
582 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
583 if (flags & MAP_ANONYMOUS) {
584 memset(p, 0, n);
585 return p;
586 }
587 ssize_t r;
588 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
589 for (q=p; n; q+=r, off+=r, n-=r) {
590 r = read(fd, q, n);
591 if (r < 0 && errno != EINTR) return MAP_FAILED;
592 if (!r) {
593 memset(q, 0, n);
594 break;
595 }
596 }
597 return p;
598 }
599
600 static void unmap_library(struct dso *dso)
601 {
602 if (dso->loadmap) {
603 size_t i;
604 for (i=0; i<dso->loadmap->nsegs; i++) {
605 if (!dso->loadmap->segs[i].p_memsz)
606 continue;
607 munmap((void *)dso->loadmap->segs[i].addr,
608 dso->loadmap->segs[i].p_memsz);
609 }
610 free(dso->loadmap);
611 } else if (dso->map && dso->map_len) {
612 munmap(dso->map, dso->map_len);
613 }
614 }
615
616 static void *map_library(int fd, struct dso *dso)
617 {
618 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
619 void *allocated_buf=0;
620 size_t phsize;
621 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
622 size_t this_min, this_max;
623 size_t nsegs = 0;
624 off_t off_start;
625 Ehdr *eh;
626 Phdr *ph, *ph0;
627 unsigned prot;
628 unsigned char *map=MAP_FAILED, *base;
629 size_t dyn=0;
630 size_t tls_image=0;
631 size_t i;
632
633 ssize_t l = read(fd, buf, sizeof buf);
634 eh = buf;
635 if (l<0) return 0;
636 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
637 goto noexec;
638 phsize = eh->e_phentsize * eh->e_phnum;
639 if (phsize > sizeof buf - sizeof *eh) {
640 allocated_buf = malloc(phsize);
641 if (!allocated_buf) return 0;
642 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
643 if (l < 0) goto error;
644 if (l != phsize) goto noexec;
645 ph = ph0 = allocated_buf;
646 } else if (eh->e_phoff + phsize > l) {
647 l = pread(fd, buf+1, phsize, eh->e_phoff);
648 if (l < 0) goto error;
649 if (l != phsize) goto noexec;
650 ph = ph0 = (void *)(buf + 1);
651 } else {
652 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
653 }
654 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
655 if (ph->p_type == PT_DYNAMIC) {
656 dyn = ph->p_vaddr;
657 } else if (ph->p_type == PT_TLS) {
658 tls_image = ph->p_vaddr;
659 dso->tls.align = ph->p_align;
660 dso->tls.len = ph->p_filesz;
661 dso->tls.size = ph->p_memsz;
662 } else if (ph->p_type == PT_GNU_RELRO) {
663 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
664 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
665 } else if (ph->p_type == PT_GNU_STACK) {
666 if (!runtime && ph->p_memsz > __default_stacksize) {
667 __default_stacksize =
668 ph->p_memsz < DEFAULT_STACK_MAX ?
669 ph->p_memsz : DEFAULT_STACK_MAX;
670 }
671 }
672 if (ph->p_type != PT_LOAD) continue;
673 nsegs++;
674 if (ph->p_vaddr < addr_min) {
675 addr_min = ph->p_vaddr;
676 off_start = ph->p_offset;
677 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
678 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
679 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
680 }
681 if (ph->p_vaddr+ph->p_memsz > addr_max) {
682 addr_max = ph->p_vaddr+ph->p_memsz;
683 }
684 }
685 if (!dyn) goto noexec;
686 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
687 dso->loadmap = calloc(1, sizeof *dso->loadmap
688 + nsegs * sizeof *dso->loadmap->segs);
689 if (!dso->loadmap) goto error;
690 dso->loadmap->nsegs = nsegs;
691 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
692 if (ph->p_type != PT_LOAD) continue;
693 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
694 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
695 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
696 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
697 prot, MAP_PRIVATE,
698 fd, ph->p_offset & -PAGE_SIZE);
699 if (map == MAP_FAILED) {
700 unmap_library(dso);
701 goto error;
702 }
703 dso->loadmap->segs[i].addr = (size_t)map +
704 (ph->p_vaddr & PAGE_SIZE-1);
705 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
706 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
707 i++;
708 if (prot & PROT_WRITE) {
709 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
710 + ph->p_filesz;
711 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
712 size_t pgend = brk + ph->p_memsz - ph->p_filesz
713 + PAGE_SIZE-1 & -PAGE_SIZE;
714 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
715 pgend-pgbrk, prot,
716 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
717 -1, off_start) == MAP_FAILED)
718 goto error;
719 memset(map + brk, 0, pgbrk-brk);
720 }
721 }
722 map = (void *)dso->loadmap->segs[0].addr;
723 map_len = 0;
724 goto done_mapping;
725 }
726 addr_max += PAGE_SIZE-1;
727 addr_max &= -PAGE_SIZE;
728 addr_min &= -PAGE_SIZE;
729 off_start &= -PAGE_SIZE;
730 map_len = addr_max - addr_min + off_start;
731 /* The first time, we map too much, possibly even more than
732 * the length of the file. This is okay because we will not
733 * use the invalid part; we just need to reserve the right
734 * amount of virtual address space to map over later. */
735 map = DL_NOMMU_SUPPORT
736 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
737 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
738 : mmap((void *)addr_min, map_len, prot,
739 MAP_PRIVATE, fd, off_start);
740 if (map==MAP_FAILED) goto error;
741 dso->map = map;
742 dso->map_len = map_len;
743 /* If the loaded file is not relocatable and the requested address is
744 * not available, then the load operation must fail. */
745 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
746 errno = EBUSY;
747 goto error;
748 }
749 base = map - addr_min;
750 dso->phdr = 0;
751 dso->phnum = 0;
752 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
753 if (ph->p_type != PT_LOAD) continue;
754 /* Check if the programs headers are in this load segment, and
755 * if so, record the address for use by dl_iterate_phdr. */
756 if (!dso->phdr && eh->e_phoff >= ph->p_offset
757 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
758 dso->phdr = (void *)(base + ph->p_vaddr
759 + (eh->e_phoff-ph->p_offset));
760 dso->phnum = eh->e_phnum;
761 dso->phentsize = eh->e_phentsize;
762 }
763 this_min = ph->p_vaddr & -PAGE_SIZE;
764 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
765 off_start = ph->p_offset & -PAGE_SIZE;
766 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
767 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
768 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
769 /* Reuse the existing mapping for the lowest-address LOAD */
770 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
771 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
772 goto error;
773 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
774 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
775 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
776 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
777 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)
778 goto error;
779 }
780 }
781 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
782 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
783 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
784 && errno != ENOSYS)
785 goto error;
786 break;
787 }
788 done_mapping:
789 dso->base = base;
790 dso->dynv = laddr(dso, dyn);
791 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
792 free(allocated_buf);
793 return map;
794 noexec:
795 errno = ENOEXEC;
796 error:
797 if (map!=MAP_FAILED) unmap_library(dso);
798 free(allocated_buf);
799 return 0;
800 }
801
802 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
803 {
804 size_t l;
805 int fd;
806 for (;;) {
807 s += strspn(s, ":\n");
808 l = strcspn(s, ":\n");
809 if (l-1 >= INT_MAX) return -1;
810 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
811 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
812 switch (errno) {
813 case ENOENT:
814 case ENOTDIR:
815 case EACCES:
816 case ENAMETOOLONG:
817 break;
818 default:
819 /* Any negative value but -1 will inhibit
820 * futher path search. */
821 return -2;
822 }
823 }
824 s += l;
825 }
826 }
827
828 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
829 {
830 size_t n, l;
831 const char *s, *t, *origin;
832 char *d;
833 if (p->rpath || !p->rpath_orig) return 0;
834 if (!strchr(p->rpath_orig, '$')) {
835 p->rpath = p->rpath_orig;
836 return 0;
837 }
838 n = 0;
839 s = p->rpath_orig;
840 while ((t=strchr(s, '$'))) {
841 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
842 return 0;
843 s = t+1;
844 n++;
845 }
846 if (n > SSIZE_MAX/PATH_MAX) return 0;
847
848 if (p->kernel_mapped) {
849 /* $ORIGIN searches cannot be performed for the main program
850 * when it is suid/sgid/AT_SECURE. This is because the
851 * pathname is under the control of the caller of execve.
852 * For libraries, however, $ORIGIN can be processed safely
853 * since the library's pathname came from a trusted source
854 * (either system paths or a call to dlopen). */
855 if (libc.secure)
856 return 0;
857 l = readlink("/proc/self/exe", buf, buf_size);
858 if (l == -1) switch (errno) {
859 case ENOENT:
860 case ENOTDIR:
861 case EACCES:
862 break;
863 default:
864 return -1;
865 }
866 if (l >= buf_size)
867 return 0;
868 buf[l] = 0;
869 origin = buf;
870 } else {
871 origin = p->name;
872 }
873 t = strrchr(origin, '/');
874 if (t) {
875 l = t-origin;
876 } else {
877 /* Normally p->name will always be an absolute or relative
878 * pathname containing at least one '/' character, but in the
879 * case where ldso was invoked as a command to execute a
880 * program in the working directory, app.name may not. Fix. */
881 origin = ".";
882 l = 1;
883 }
884 /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
885 if (libc.secure && *origin != '/')
886 return 0;
887 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
888 if (!p->rpath) return -1;
889
890 d = p->rpath;
891 s = p->rpath_orig;
892 while ((t=strchr(s, '$'))) {
893 memcpy(d, s, t-s);
894 d += t-s;
895 memcpy(d, origin, l);
896 d += l;
897 /* It was determined previously that the '$' is followed
898 * either by "ORIGIN" or "{ORIGIN}". */
899 s = t + 7 + 2*(t[1]=='{');
900 }
901 strcpy(d, s);
902 return 0;
903 }
904
905 static void decode_dyn(struct dso *p)
906 {
907 size_t dyn[DYN_CNT];
908 decode_vec(p->dynv, dyn, DYN_CNT);
909 p->syms = laddr(p, dyn[DT_SYMTAB]);
910 p->strings = laddr(p, dyn[DT_STRTAB]);
911 if (dyn[0]&(1<<DT_HASH))
912 p->hashtab = laddr(p, dyn[DT_HASH]);
913 if (dyn[0]&(1<<DT_RPATH))
914 p->rpath_orig = p->strings + dyn[DT_RPATH];
915 if (dyn[0]&(1<<DT_RUNPATH))
916 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
917 if (dyn[0]&(1<<DT_PLTGOT))
918 p->got = laddr(p, dyn[DT_PLTGOT]);
919 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
920 p->ghashtab = laddr(p, *dyn);
921 if (search_vec(p->dynv, dyn, DT_VERSYM))
922 p->versym = laddr(p, *dyn);
923 }
924
925 static size_t count_syms(struct dso *p)
926 {
927 if (p->hashtab) return p->hashtab[1];
928
929 size_t nsym, i;
930 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
931 uint32_t *hashval;
932 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
933 if (buckets[i] > nsym)
934 nsym = buckets[i];
935 }
936 if (nsym) {
937 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
938 do nsym++;
939 while (!(*hashval++ & 1));
940 }
941 return nsym;
942 }
943
944 static void *dl_mmap(size_t n)
945 {
946 void *p;
947 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
948 #ifdef SYS_mmap2
949 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
950 #else
951 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
952 #endif
953 return (unsigned long)p > -4096UL ? 0 : p;
954 }
955
956 static void makefuncdescs(struct dso *p)
957 {
958 static int self_done;
959 size_t nsym = count_syms(p);
960 size_t i, size = nsym * sizeof(*p->funcdescs);
961
962 if (!self_done) {
963 p->funcdescs = dl_mmap(size);
964 self_done = 1;
965 } else {
966 p->funcdescs = malloc(size);
967 }
968 if (!p->funcdescs) {
969 if (!runtime) a_crash();
970 error("Error allocating function descriptors for %s", p->name);
971 longjmp(*rtld_fail, 1);
972 }
973 for (i=0; i<nsym; i++) {
974 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
975 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
976 p->funcdescs[i].got = p->got;
977 } else {
978 p->funcdescs[i].addr = 0;
979 p->funcdescs[i].got = 0;
980 }
981 }
982 }
983
984 static struct dso *load_library(const char *name, struct dso *needed_by)
985 {
986 char buf[2*NAME_MAX+2];
987 const char *pathname;
988 unsigned char *map;
989 struct dso *p, temp_dso = {0};
990 int fd;
991 struct stat st;
992 size_t alloc_size;
993 int n_th = 0;
994 int is_self = 0;
995
996 if (!*name) {
997 errno = EINVAL;
998 return 0;
999 }
1000
1001 /* Catch and block attempts to reload the implementation itself */
1002 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
1003 static const char reserved[] =
1004 "c.pthread.rt.m.dl.util.xnet.";
1005 const char *rp, *next;
1006 for (rp=reserved; *rp; rp=next) {
1007 next = strchr(rp, '.') + 1;
1008 if (strncmp(name+3, rp, next-rp) == 0)
1009 break;
1010 }
1011 if (*rp) {
1012 if (ldd_mode) {
1013 /* Track which names have been resolved
1014 * and only report each one once. */
1015 static unsigned reported;
1016 unsigned mask = 1U<<(rp-reserved);
1017 if (!(reported & mask)) {
1018 reported |= mask;
1019 dprintf(1, "\t%s => %s (%p)\n",
1020 name, ldso.name,
1021 ldso.base);
1022 }
1023 }
1024 is_self = 1;
1025 }
1026 }
1027 if (!strcmp(name, ldso.name)) is_self = 1;
1028 if (is_self) {
1029 if (!ldso.prev) {
1030 tail->next = &ldso;
1031 ldso.prev = tail;
1032 tail = &ldso;
1033 }
1034 return &ldso;
1035 }
1036 if (strchr(name, '/')) {
1037 pathname = name;
1038 fd = open(name, O_RDONLY|O_CLOEXEC);
1039 } else {
1040 /* Search for the name to see if it's already loaded */
1041 for (p=head->next; p; p=p->next) {
1042 if (p->shortname && !strcmp(p->shortname, name)) {
1043 return p;
1044 }
1045 }
1046 if (strlen(name) > NAME_MAX) return 0;
1047 fd = -1;
1048 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
1049 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
1050 if (fixup_rpath(p, buf, sizeof buf) < 0)
1051 fd = -2; /* Inhibit further search. */
1052 if (p->rpath)
1053 fd = path_open(name, p->rpath, buf, sizeof buf);
1054 }
1055 if (fd == -1) {
1056 if (!sys_path) {
1057 char *prefix = 0;
1058 size_t prefix_len;
1059 if (ldso.name[0]=='/') {
1060 char *s, *t, *z;
1061 for (s=t=z=ldso.name; *s; s++)
1062 if (*s=='/') z=t, t=s;
1063 prefix_len = z-ldso.name;
1064 if (prefix_len < PATH_MAX)
1065 prefix = ldso.name;
1066 }
1067 if (!prefix) {
1068 prefix = "";
1069 prefix_len = 0;
1070 }
1071 char etc_ldso_path[prefix_len + 1
1072 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1073 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1074 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1075 (int)prefix_len, prefix);
1076 fd = open(etc_ldso_path, O_RDONLY|O_CLOEXEC);
1077 if (fd>=0) {
1078 size_t n = 0;
1079 if (!fstat(fd, &st)) n = st.st_size;
1080 if ((sys_path = malloc(n+1)))
1081 sys_path[n] = 0;
1082 if (!sys_path || read_loop(fd, sys_path, n)<0) {
1083 free(sys_path);
1084 sys_path = "";
1085 }
1086 close(fd);
1087 } else if (errno != ENOENT) {
1088 sys_path = "";
1089 }
1090 }
1091 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1092 fd = path_open(name, sys_path, buf, sizeof buf);
1093 }
1094 pathname = buf;
1095 }
1096 if (fd < 0) return 0;
1097 if (fstat(fd, &st) < 0) {
1098 close(fd);
1099 return 0;
1100 }
1101 for (p=head->next; p; p=p->next) {
1102 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1103 /* If this library was previously loaded with a
1104 * pathname but a search found the same inode,
1105 * setup its shortname so it can be found by name. */
1106 if (!p->shortname && pathname != name)
1107 p->shortname = strrchr(p->name, '/')+1;
1108 close(fd);
1109 return p;
1110 }
1111 }
1112 map = noload ? 0 : map_library(fd, &temp_dso);
1113 close(fd);
1114 if (!map) return 0;
1115
1116 /* Avoid the danger of getting two versions of libc mapped into the
1117 * same process when an absolute pathname was used. The symbols
1118 * checked are chosen to catch both musl and glibc, and to avoid
1119 * false positives from interposition-hack libraries. */
1120 decode_dyn(&temp_dso);
1121 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1122 find_sym(&temp_dso, "stdin", 1).sym) {
1123 unmap_library(&temp_dso);
1124 return load_library("libc.so", needed_by);
1125 }
1126 /* Past this point, if we haven't reached runtime yet, ldso has
1127 * committed either to use the mapped library or to abort execution.
1128 * Unmapping is not possible, so we can safely reclaim gaps. */
1129 if (!runtime) reclaim_gaps(&temp_dso);
1130
1131 /* Allocate storage for the new DSO. When there is TLS, this
1132 * storage must include a reservation for all pre-existing
1133 * threads to obtain copies of both the new TLS, and an
1134 * extended DTV capable of storing an additional slot for
1135 * the newly-loaded DSO. */
1136 alloc_size = sizeof *p + strlen(pathname) + 1;
1137 if (runtime && temp_dso.tls.image) {
1138 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1139 + sizeof(void *) * (tls_cnt+3);
1140 n_th = libc.threads_minus_1 + 1;
1141 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1142 else alloc_size += n_th * per_th;
1143 }
1144 p = calloc(1, alloc_size);
1145 if (!p) {
1146 unmap_library(&temp_dso);
1147 return 0;
1148 }
1149 memcpy(p, &temp_dso, sizeof temp_dso);
1150 p->dev = st.st_dev;
1151 p->ino = st.st_ino;
1152 p->needed_by = needed_by;
1153 p->name = p->buf;
1154 p->runtime_loaded = runtime;
1155 strcpy(p->name, pathname);
1156 /* Add a shortname only if name arg was not an explicit pathname. */
1157 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1158 if (p->tls.image) {
1159 p->tls_id = ++tls_cnt;
1160 tls_align = MAXP2(tls_align, p->tls.align);
1161 #ifdef TLS_ABOVE_TP
1162 p->tls.offset = tls_offset + ( (p->tls.align-1) &
1163 (-tls_offset + (uintptr_t)p->tls.image) );
1164 tls_offset = p->tls.offset + p->tls.size;
1165 #else
1166 tls_offset += p->tls.size + p->tls.align - 1;
1167 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1168 & (p->tls.align-1);
1169 p->tls.offset = tls_offset;
1170 #endif
1171 p->new_dtv = (void *)(-sizeof(size_t) &
1172 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1173 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1174 if (tls_tail) tls_tail->next = &p->tls;
1175 else libc.tls_head = &p->tls;
1176 tls_tail = &p->tls;
1177 }
1178
1179 tail->next = p;
1180 p->prev = tail;
1181 tail = p;
1182
1183 if (DL_FDPIC) makefuncdescs(p);
1184
1185 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1186
1187 return p;
1188 }
1189
1190 static void load_direct_deps(struct dso *p)
1191 {
1192 size_t i, cnt=0;
1193
1194 if (p->deps) return;
1195 /* For head, all preloads are direct pseudo-dependencies.
1196 * Count and include them now to avoid realloc later. */
1197 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1198 cnt++;
1199 for (i=0; p->dynv[i]; i+=2)
1200 if (p->dynv[i] == DT_NEEDED) cnt++;
1201 /* Use builtin buffer for apps with no external deps, to
1202 * preserve property of no runtime failure paths. */
1203 p->deps = (p==head && cnt<2) ? builtin_deps :
1204 calloc(cnt+1, sizeof *p->deps);
1205 if (!p->deps) {
1206 error("Error loading dependencies for %s", p->name);
1207 if (runtime) longjmp(*rtld_fail, 1);
1208 }
1209 cnt=0;
1210 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1211 p->deps[cnt++] = q;
1212 for (i=0; p->dynv[i]; i+=2) {
1213 if (p->dynv[i] != DT_NEEDED) continue;
1214 struct dso *dep = load_library(p->strings + p->dynv[i+1], p);
1215 if (!dep) {
1216 error("Error loading shared library %s: %m (needed by %s)",
1217 p->strings + p->dynv[i+1], p->name);
1218 if (runtime) longjmp(*rtld_fail, 1);
1219 continue;
1220 }
1221 p->deps[cnt++] = dep;
1222 }
1223 p->deps[cnt] = 0;
1224 p->ndeps_direct = cnt;
1225 }
1226
1227 static void load_deps(struct dso *p)
1228 {
1229 if (p->deps) return;
1230 for (; p; p=p->next)
1231 load_direct_deps(p);
1232 }
1233
1234 static void extend_bfs_deps(struct dso *p)
1235 {
1236 size_t i, j, cnt, ndeps_all;
1237 struct dso **tmp;
1238
1239 /* Can't use realloc if the original p->deps was allocated at
1240 * program entry and malloc has been replaced, or if it's
1241 * the builtin non-allocated trivial main program deps array. */
1242 int no_realloc = (__malloc_replaced && !p->runtime_loaded)
1243 || p->deps == builtin_deps;
1244
1245 if (p->bfs_built) return;
1246 ndeps_all = p->ndeps_direct;
1247
1248 /* Mark existing (direct) deps so they won't be duplicated. */
1249 for (i=0; p->deps[i]; i++)
1250 p->deps[i]->mark = 1;
1251
1252 /* For each dependency already in the list, copy its list of direct
1253 * dependencies to the list, excluding any items already in the
1254 * list. Note that the list this loop iterates over will grow during
1255 * the loop, but since duplicates are excluded, growth is bounded. */
1256 for (i=0; p->deps[i]; i++) {
1257 struct dso *dep = p->deps[i];
1258 for (j=cnt=0; j<dep->ndeps_direct; j++)
1259 if (!dep->deps[j]->mark) cnt++;
1260 tmp = no_realloc ?
1261 malloc(sizeof(*tmp) * (ndeps_all+cnt+1)) :
1262 realloc(p->deps, sizeof(*tmp) * (ndeps_all+cnt+1));
1263 if (!tmp) {
1264 error("Error recording dependencies for %s", p->name);
1265 if (runtime) longjmp(*rtld_fail, 1);
1266 continue;
1267 }
1268 if (no_realloc) {
1269 memcpy(tmp, p->deps, sizeof(*tmp) * (ndeps_all+1));
1270 no_realloc = 0;
1271 }
1272 p->deps = tmp;
1273 for (j=0; j<dep->ndeps_direct; j++) {
1274 if (dep->deps[j]->mark) continue;
1275 dep->deps[j]->mark = 1;
1276 p->deps[ndeps_all++] = dep->deps[j];
1277 }
1278 p->deps[ndeps_all] = 0;
1279 }
1280 p->bfs_built = 1;
1281 for (p=head; p; p=p->next)
1282 p->mark = 0;
1283 }
1284
1285 static void load_preload(char *s)
1286 {
1287 int tmp;
1288 char *z;
1289 for (z=s; *z; s=z) {
1290 for ( ; *s && (isspace(*s) || *s==':'); s++);
1291 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1292 tmp = *z;
1293 *z = 0;
1294 load_library(s, 0);
1295 *z = tmp;
1296 }
1297 }
1298
1299 static void add_syms(struct dso *p)
1300 {
1301 if (!p->syms_next && syms_tail != p) {
1302 syms_tail->syms_next = p;
1303 syms_tail = p;
1304 }
1305 }
1306
1307 static void revert_syms(struct dso *old_tail)
1308 {
1309 struct dso *p, *next;
1310 /* Chop off the tail of the list of dsos that participate in
1311 * the global symbol table, reverting them to RTLD_LOCAL. */
1312 for (p=old_tail; p; p=next) {
1313 next = p->syms_next;
1314 p->syms_next = 0;
1315 }
1316 syms_tail = old_tail;
1317 }
1318
1319 static void do_mips_relocs(struct dso *p, size_t *got)
1320 {
1321 size_t i, j, rel[2];
1322 unsigned char *base = p->base;
1323 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1324 if (p==&ldso) {
1325 got += i;
1326 } else {
1327 while (i--) *got++ += (size_t)base;
1328 }
1329 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1330 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1331 Sym *sym = p->syms + j;
1332 rel[0] = (unsigned char *)got - base;
1333 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1334 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1335 do_relocs(p, rel, sizeof rel, 2);
1336 }
1337 }
1338
1339 static void reloc_all(struct dso *p)
1340 {
1341 size_t dyn[DYN_CNT];
1342 for (; p; p=p->next) {
1343 if (p->relocated) continue;
1344 decode_vec(p->dynv, dyn, DYN_CNT);
1345 if (NEED_MIPS_GOT_RELOCS)
1346 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1347 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1348 2+(dyn[DT_PLTREL]==DT_RELA));
1349 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1350 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1351
1352 if (head != &ldso && p->relro_start != p->relro_end &&
1353 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1354 && errno != ENOSYS) {
1355 error("Error relocating %s: RELRO protection failed: %m",
1356 p->name);
1357 if (runtime) longjmp(*rtld_fail, 1);
1358 }
1359
1360 p->relocated = 1;
1361 }
1362 }
1363
1364 static void kernel_mapped_dso(struct dso *p)
1365 {
1366 size_t min_addr = -1, max_addr = 0, cnt;
1367 Phdr *ph = p->phdr;
1368 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1369 if (ph->p_type == PT_DYNAMIC) {
1370 p->dynv = laddr(p, ph->p_vaddr);
1371 } else if (ph->p_type == PT_GNU_RELRO) {
1372 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1373 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1374 } else if (ph->p_type == PT_GNU_STACK) {
1375 if (!runtime && ph->p_memsz > __default_stacksize) {
1376 __default_stacksize =
1377 ph->p_memsz < DEFAULT_STACK_MAX ?
1378 ph->p_memsz : DEFAULT_STACK_MAX;
1379 }
1380 }
1381 if (ph->p_type != PT_LOAD) continue;
1382 if (ph->p_vaddr < min_addr)
1383 min_addr = ph->p_vaddr;
1384 if (ph->p_vaddr+ph->p_memsz > max_addr)
1385 max_addr = ph->p_vaddr+ph->p_memsz;
1386 }
1387 min_addr &= -PAGE_SIZE;
1388 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1389 p->map = p->base + min_addr;
1390 p->map_len = max_addr - min_addr;
1391 p->kernel_mapped = 1;
1392 }
1393
1394 void __libc_exit_fini()
1395 {
1396 struct dso *p;
1397 size_t dyn[DYN_CNT];
1398 pthread_t self = __pthread_self();
1399
1400 /* Take both locks before setting shutting_down, so that
1401 * either lock is sufficient to read its value. The lock
1402 * order matches that in dlopen to avoid deadlock. */
1403 pthread_rwlock_wrlock(&lock);
1404 pthread_mutex_lock(&init_fini_lock);
1405 shutting_down = 1;
1406 pthread_rwlock_unlock(&lock);
1407 for (p=fini_head; p; p=p->fini_next) {
1408 while (p->ctor_visitor && p->ctor_visitor!=self)
1409 pthread_cond_wait(&ctor_cond, &init_fini_lock);
1410 if (!p->constructed) continue;
1411 decode_vec(p->dynv, dyn, DYN_CNT);
1412 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1413 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1414 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1415 while (n--) ((void (*)(void))*--fn)();
1416 }
1417 #ifndef NO_LEGACY_INITFINI
1418 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1419 fpaddr(p, dyn[DT_FINI])();
1420 #endif
1421 }
1422 }
1423
1424 static struct dso **queue_ctors(struct dso *dso)
1425 {
1426 size_t cnt, qpos, spos, i;
1427 struct dso *p, **queue, **stack;
1428
1429 if (ldd_mode) return 0;
1430
1431 /* Bound on queue size is the total number of indirect deps.
1432 * If a bfs deps list was built, we can use it. Otherwise,
1433 * bound by the total number of DSOs, which is always safe and
1434 * is reasonable we use it (for main app at startup). */
1435 if (dso->bfs_built) {
1436 for (cnt=0; dso->deps[cnt]; cnt++)
1437 dso->deps[cnt]->mark = 0;
1438 cnt++; /* self, not included in deps */
1439 } else {
1440 for (cnt=0, p=head; p; cnt++, p=p->next)
1441 p->mark = 0;
1442 }
1443 cnt++; /* termination slot */
1444 if (dso==head && cnt <= countof(builtin_ctor_queue))
1445 queue = builtin_ctor_queue;
1446 else
1447 queue = calloc(cnt, sizeof *queue);
1448
1449 if (!queue) {
1450 error("Error allocating constructor queue: %m\n");
1451 if (runtime) longjmp(*rtld_fail, 1);
1452 return 0;
1453 }
1454
1455 /* Opposite ends of the allocated buffer serve as an output queue
1456 * and a working stack. Setup initial stack with just the argument
1457 * dso and initial queue empty... */
1458 stack = queue;
1459 qpos = 0;
1460 spos = cnt;
1461 stack[--spos] = dso;
1462 dso->next_dep = 0;
1463 dso->mark = 1;
1464
1465 /* Then perform pseudo-DFS sort, but ignoring circular deps. */
1466 while (spos<cnt) {
1467 p = stack[spos++];
1468 while (p->next_dep < p->ndeps_direct) {
1469 if (p->deps[p->next_dep]->mark) {
1470 p->next_dep++;
1471 } else {
1472 stack[--spos] = p;
1473 p = p->deps[p->next_dep];
1474 p->next_dep = 0;
1475 p->mark = 1;
1476 }
1477 }
1478 queue[qpos++] = p;
1479 }
1480 queue[qpos] = 0;
1481 for (i=0; i<qpos; i++) queue[i]->mark = 0;
1482
1483 return queue;
1484 }
1485
1486 static void do_init_fini(struct dso **queue)
1487 {
1488 struct dso *p;
1489 size_t dyn[DYN_CNT], i;
1490 pthread_t self = __pthread_self();
1491
1492 pthread_mutex_lock(&init_fini_lock);
1493 for (i=0; (p=queue[i]); i++) {
1494 while ((p->ctor_visitor && p->ctor_visitor!=self) || shutting_down)
1495 pthread_cond_wait(&ctor_cond, &init_fini_lock);
1496 if (p->ctor_visitor || p->constructed)
1497 continue;
1498 p->ctor_visitor = self;
1499
1500 decode_vec(p->dynv, dyn, DYN_CNT);
1501 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1502 p->fini_next = fini_head;
1503 fini_head = p;
1504 }
1505
1506 pthread_mutex_unlock(&init_fini_lock);
1507
1508 #ifndef NO_LEGACY_INITFINI
1509 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1510 fpaddr(p, dyn[DT_INIT])();
1511 #endif
1512 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1513 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1514 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1515 while (n--) ((void (*)(void))*fn++)();
1516 }
1517
1518 pthread_mutex_lock(&init_fini_lock);
1519 p->ctor_visitor = 0;
1520 p->constructed = 1;
1521 pthread_cond_broadcast(&ctor_cond);
1522 }
1523 pthread_mutex_unlock(&init_fini_lock);
1524 }
1525
1526 void __libc_start_init(void)
1527 {
1528 do_init_fini(main_ctor_queue);
1529 if (!__malloc_replaced && main_ctor_queue != builtin_ctor_queue)
1530 free(main_ctor_queue);
1531 main_ctor_queue = 0;
1532 }
1533
1534 static void dl_debug_state(void)
1535 {
1536 }
1537
1538 weak_alias(dl_debug_state, _dl_debug_state);
1539
1540 void __init_tls(size_t *auxv)
1541 {
1542 }
1543
1544 static void update_tls_size()
1545 {
1546 libc.tls_cnt = tls_cnt;
1547 libc.tls_align = tls_align;
1548 libc.tls_size = ALIGN(
1549 (1+tls_cnt) * sizeof(void *) +
1550 tls_offset +
1551 sizeof(struct pthread) +
1552 tls_align * 2,
1553 tls_align);
1554 }
1555
1556 static void install_new_tls(void)
1557 {
1558 sigset_t set;
1559 pthread_t self = __pthread_self(), td;
1560 struct dso *dtv_provider = container_of(tls_tail, struct dso, tls);
1561 uintptr_t (*newdtv)[tls_cnt+1] = (void *)dtv_provider->new_dtv;
1562 struct dso *p;
1563 size_t i, j;
1564 size_t old_cnt = self->dtv[0];
1565
1566 __block_app_sigs(&set);
1567 __tl_lock();
1568 /* Copy existing dtv contents from all existing threads. */
1569 for (i=0, td=self; !i || td!=self; i++, td=td->next) {
1570 memcpy(newdtv+i, td->dtv,
1571 (old_cnt+1)*sizeof(uintptr_t));
1572 newdtv[i][0] = tls_cnt;
1573 }
1574 /* Install new dtls into the enlarged, uninstalled dtv copies. */
1575 for (p=head; ; p=p->next) {
1576 if (p->tls_id <= old_cnt) continue;
1577 unsigned char *mem = p->new_tls;
1578 for (j=0; j<i; j++) {
1579 unsigned char *new = mem;
1580 new += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1581 & (p->tls.align-1);
1582 memcpy(new, p->tls.image, p->tls.len);
1583 newdtv[j][p->tls_id] =
1584 (uintptr_t)new + DTP_OFFSET;
1585 mem += p->tls.size + p->tls.align;
1586 }
1587 if (p->tls_id == tls_cnt) break;
1588 }
1589
1590 /* Broadcast barrier to ensure contents of new dtv is visible
1591 * if the new dtv pointer is. The __membarrier function has a
1592 * fallback emulation using signals for kernels that lack the
1593 * feature at the syscall level. */
1594
1595 __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED, 0);
1596
1597 /* Install new dtv for each thread. */
1598 for (j=0, td=self; !j || td!=self; j++, td=td->next) {
1599 td->dtv = newdtv[j];
1600 }
1601
1602 __tl_unlock();
1603 __restore_sigs(&set);
1604 }
1605
1606 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1607 * following stage 2 and stage 3 functions via primitive symbolic lookup
1608 * since it does not have access to their addresses to begin with. */
1609
1610 /* Stage 2 of the dynamic linker is called after relative relocations
1611 * have been processed. It can make function calls to static functions
1612 * and access string literals and static data, but cannot use extern
1613 * symbols. Its job is to perform symbolic relocations on the dynamic
1614 * linker itself, but some of the relocations performed may need to be
1615 * replaced later due to copy relocations in the main program. */
1616
1617 hidden void __dls2(unsigned char *base, size_t *sp)
1618 {
1619 size_t *auxv;
1620 for (auxv=sp+1+*sp+1; *auxv; auxv++);
1621 auxv++;
1622 if (DL_FDPIC) {
1623 void *p1 = (void *)sp[-2];
1624 void *p2 = (void *)sp[-1];
1625 if (!p1) {
1626 size_t aux[AUX_CNT];
1627 decode_vec(auxv, aux, AUX_CNT);
1628 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1629 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1630 }
1631 app_loadmap = p2 ? p1 : 0;
1632 ldso.loadmap = p2 ? p2 : p1;
1633 ldso.base = laddr(&ldso, 0);
1634 } else {
1635 ldso.base = base;
1636 }
1637 Ehdr *ehdr = (void *)ldso.base;
1638 ldso.name = ldso.shortname = "libc.so";
1639 ldso.phnum = ehdr->e_phnum;
1640 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1641 ldso.phentsize = ehdr->e_phentsize;
1642 kernel_mapped_dso(&ldso);
1643 decode_dyn(&ldso);
1644
1645 if (DL_FDPIC) makefuncdescs(&ldso);
1646
1647 /* Prepare storage for to save clobbered REL addends so they
1648 * can be reused in stage 3. There should be very few. If
1649 * something goes wrong and there are a huge number, abort
1650 * instead of risking stack overflow. */
1651 size_t dyn[DYN_CNT];
1652 decode_vec(ldso.dynv, dyn, DYN_CNT);
1653 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1654 size_t rel_size = dyn[DT_RELSZ];
1655 size_t symbolic_rel_cnt = 0;
1656 apply_addends_to = rel;
1657 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1658 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1659 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1660 size_t addends[symbolic_rel_cnt+1];
1661 saved_addends = addends;
1662
1663 head = &ldso;
1664 reloc_all(&ldso);
1665
1666 ldso.relocated = 0;
1667
1668 /* Call dynamic linker stage-2b, __dls2b, looking it up
1669 * symbolically as a barrier against moving the address
1670 * load across the above relocation processing. */
1671 struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0);
1672 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp, auxv);
1673 else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp, auxv);
1674 }
1675
1676 /* Stage 2b sets up a valid thread pointer, which requires relocations
1677 * completed in stage 2, and on which stage 3 is permitted to depend.
1678 * This is done as a separate stage, with symbolic lookup as a barrier,
1679 * so that loads of the thread pointer and &errno can be pure/const and
1680 * thereby hoistable. */
1681
1682 void __dls2b(size_t *sp, size_t *auxv)
1683 {
1684 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1685 * use during dynamic linking. If possible it will also serve as the
1686 * thread pointer at runtime. */
1687 search_vec(auxv, &__hwcap, AT_HWCAP);
1688 libc.auxv = auxv;
1689 libc.tls_size = sizeof builtin_tls;
1690 libc.tls_align = tls_align;
1691 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1692 a_crash();
1693 }
1694
1695 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1696 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp, auxv);
1697 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp, auxv);
1698 }
1699
1700 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1701 * fully functional. Its job is to load (if not already loaded) and
1702 * process dependencies and relocations for the main application and
1703 * transfer control to its entry point. */
1704
1705 void __dls3(size_t *sp, size_t *auxv)
1706 {
1707 static struct dso app, vdso;
1708 size_t aux[AUX_CNT];
1709 size_t i;
1710 char *env_preload=0;
1711 char *replace_argv0=0;
1712 size_t vdso_base;
1713 int argc = *sp;
1714 char **argv = (void *)(sp+1);
1715 char **argv_orig = argv;
1716 char **envp = argv+argc+1;
1717
1718 /* Find aux vector just past environ[] and use it to initialize
1719 * global data that may be needed before we can make syscalls. */
1720 __environ = envp;
1721 decode_vec(auxv, aux, AUX_CNT);
1722 search_vec(auxv, &__sysinfo, AT_SYSINFO);
1723 __pthread_self()->sysinfo = __sysinfo;
1724 libc.page_size = aux[AT_PAGESZ];
1725 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1726 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1727
1728 /* Only trust user/env if kernel says we're not suid/sgid */
1729 if (!libc.secure) {
1730 env_path = getenv("LD_LIBRARY_PATH");
1731 env_preload = getenv("LD_PRELOAD");
1732 }
1733
1734 /* If the main program was already loaded by the kernel,
1735 * AT_PHDR will point to some location other than the dynamic
1736 * linker's program headers. */
1737 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1738 size_t interp_off = 0;
1739 size_t tls_image = 0;
1740 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1741 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1742 app.phnum = aux[AT_PHNUM];
1743 app.phentsize = aux[AT_PHENT];
1744 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1745 if (phdr->p_type == PT_PHDR)
1746 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1747 else if (phdr->p_type == PT_INTERP)
1748 interp_off = (size_t)phdr->p_vaddr;
1749 else if (phdr->p_type == PT_TLS) {
1750 tls_image = phdr->p_vaddr;
1751 app.tls.len = phdr->p_filesz;
1752 app.tls.size = phdr->p_memsz;
1753 app.tls.align = phdr->p_align;
1754 }
1755 }
1756 if (DL_FDPIC) app.loadmap = app_loadmap;
1757 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1758 if (interp_off) ldso.name = laddr(&app, interp_off);
1759 if ((aux[0] & (1UL<<AT_EXECFN))
1760 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1761 app.name = (char *)aux[AT_EXECFN];
1762 else
1763 app.name = argv[0];
1764 kernel_mapped_dso(&app);
1765 } else {
1766 int fd;
1767 char *ldname = argv[0];
1768 size_t l = strlen(ldname);
1769 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1770 argv++;
1771 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1772 char *opt = argv[0]+2;
1773 *argv++ = (void *)-1;
1774 if (!*opt) {
1775 break;
1776 } else if (!memcmp(opt, "list", 5)) {
1777 ldd_mode = 1;
1778 } else if (!memcmp(opt, "library-path", 12)) {
1779 if (opt[12]=='=') env_path = opt+13;
1780 else if (opt[12]) *argv = 0;
1781 else if (*argv) env_path = *argv++;
1782 } else if (!memcmp(opt, "preload", 7)) {
1783 if (opt[7]=='=') env_preload = opt+8;
1784 else if (opt[7]) *argv = 0;
1785 else if (*argv) env_preload = *argv++;
1786 } else if (!memcmp(opt, "argv0", 5)) {
1787 if (opt[5]=='=') replace_argv0 = opt+6;
1788 else if (opt[5]) *argv = 0;
1789 else if (*argv) replace_argv0 = *argv++;
1790 } else {
1791 argv[0] = 0;
1792 }
1793 }
1794 argv[-1] = (void *)(argc - (argv-argv_orig));
1795 if (!argv[0]) {
1796 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1797 "Version %s\n"
1798 "Dynamic Program Loader\n"
1799 "Usage: %s [options] [--] pathname%s\n",
1800 __libc_version, ldname,
1801 ldd_mode ? "" : " [args]");
1802 _exit(1);
1803 }
1804 fd = open(argv[0], O_RDONLY);
1805 if (fd < 0) {
1806 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1807 _exit(1);
1808 }
1809 Ehdr *ehdr = (void *)map_library(fd, &app);
1810 if (!ehdr) {
1811 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1812 _exit(1);
1813 }
1814 close(fd);
1815 ldso.name = ldname;
1816 app.name = argv[0];
1817 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1818 /* Find the name that would have been used for the dynamic
1819 * linker had ldd not taken its place. */
1820 if (ldd_mode) {
1821 for (i=0; i<app.phnum; i++) {
1822 if (app.phdr[i].p_type == PT_INTERP)
1823 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1824 }
1825 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1826 }
1827 }
1828 if (app.tls.size) {
1829 libc.tls_head = tls_tail = &app.tls;
1830 app.tls_id = tls_cnt = 1;
1831 #ifdef TLS_ABOVE_TP
1832 app.tls.offset = GAP_ABOVE_TP;
1833 app.tls.offset += (-GAP_ABOVE_TP + (uintptr_t)app.tls.image)
1834 & (app.tls.align-1);
1835 tls_offset = app.tls.offset + app.tls.size;
1836 #else
1837 tls_offset = app.tls.offset = app.tls.size
1838 + ( -((uintptr_t)app.tls.image + app.tls.size)
1839 & (app.tls.align-1) );
1840 #endif
1841 tls_align = MAXP2(tls_align, app.tls.align);
1842 }
1843 decode_dyn(&app);
1844 if (DL_FDPIC) {
1845 makefuncdescs(&app);
1846 if (!app.loadmap) {
1847 app.loadmap = (void *)&app_dummy_loadmap;
1848 app.loadmap->nsegs = 1;
1849 app.loadmap->segs[0].addr = (size_t)app.map;
1850 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1851 - (size_t)app.base;
1852 app.loadmap->segs[0].p_memsz = app.map_len;
1853 }
1854 argv[-3] = (void *)app.loadmap;
1855 }
1856
1857 /* Initial dso chain consists only of the app. */
1858 head = tail = syms_tail = &app;
1859
1860 /* Donate unused parts of app and library mapping to malloc */
1861 reclaim_gaps(&app);
1862 reclaim_gaps(&ldso);
1863
1864 /* Load preload/needed libraries, add symbols to global namespace. */
1865 ldso.deps = (struct dso **)no_deps;
1866 if (env_preload) load_preload(env_preload);
1867 load_deps(&app);
1868 for (struct dso *p=head; p; p=p->next)
1869 add_syms(p);
1870
1871 /* Attach to vdso, if provided by the kernel, last so that it does
1872 * not become part of the global namespace. */
1873 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1874 Ehdr *ehdr = (void *)vdso_base;
1875 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1876 vdso.phnum = ehdr->e_phnum;
1877 vdso.phentsize = ehdr->e_phentsize;
1878 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1879 if (phdr->p_type == PT_DYNAMIC)
1880 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1881 if (phdr->p_type == PT_LOAD)
1882 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1883 }
1884 vdso.name = "";
1885 vdso.shortname = "linux-gate.so.1";
1886 vdso.relocated = 1;
1887 vdso.deps = (struct dso **)no_deps;
1888 decode_dyn(&vdso);
1889 vdso.prev = tail;
1890 tail->next = &vdso;
1891 tail = &vdso;
1892 }
1893
1894 for (i=0; app.dynv[i]; i+=2) {
1895 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1896 app.dynv[i+1] = (size_t)&debug;
1897 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1898 size_t *ptr = (size_t *) app.dynv[i+1];
1899 *ptr = (size_t)&debug;
1900 }
1901 }
1902
1903 /* This must be done before final relocations, since it calls
1904 * malloc, which may be provided by the application. Calling any
1905 * application code prior to the jump to its entry point is not
1906 * valid in our model and does not work with FDPIC, where there
1907 * are additional relocation-like fixups that only the entry point
1908 * code can see to perform. */
1909 main_ctor_queue = queue_ctors(&app);
1910
1911 /* Initial TLS must also be allocated before final relocations
1912 * might result in calloc being a call to application code. */
1913 update_tls_size();
1914 void *initial_tls = builtin_tls;
1915 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1916 initial_tls = calloc(libc.tls_size, 1);
1917 if (!initial_tls) {
1918 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1919 argv[0], libc.tls_size);
1920 _exit(127);
1921 }
1922 }
1923 static_tls_cnt = tls_cnt;
1924
1925 /* The main program must be relocated LAST since it may contain
1926 * copy relocations which depend on libraries' relocations. */
1927 reloc_all(app.next);
1928 reloc_all(&app);
1929
1930 /* Actual copying to new TLS needs to happen after relocations,
1931 * since the TLS images might have contained relocated addresses. */
1932 if (initial_tls != builtin_tls) {
1933 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1934 a_crash();
1935 }
1936 } else {
1937 size_t tmp_tls_size = libc.tls_size;
1938 pthread_t self = __pthread_self();
1939 /* Temporarily set the tls size to the full size of
1940 * builtin_tls so that __copy_tls will use the same layout
1941 * as it did for before. Then check, just to be safe. */
1942 libc.tls_size = sizeof builtin_tls;
1943 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1944 libc.tls_size = tmp_tls_size;
1945 }
1946
1947 if (ldso_fail) _exit(127);
1948 if (ldd_mode) _exit(0);
1949
1950 /* Determine if malloc was interposed by a replacement implementation
1951 * so that calloc and the memalign family can harden against the
1952 * possibility of incomplete replacement. */
1953 if (find_sym(head, "malloc", 1).dso != &ldso)
1954 __malloc_replaced = 1;
1955 if (find_sym(head, "aligned_alloc", 1).dso != &ldso)
1956 __aligned_alloc_replaced = 1;
1957
1958 /* Switch to runtime mode: any further failures in the dynamic
1959 * linker are a reportable failure rather than a fatal startup
1960 * error. */
1961 runtime = 1;
1962
1963 debug.ver = 1;
1964 debug.bp = dl_debug_state;
1965 debug.head = head;
1966 debug.base = ldso.base;
1967 debug.state = RT_CONSISTENT;
1968 _dl_debug_state();
1969
1970 if (replace_argv0) argv[0] = replace_argv0;
1971
1972 errno = 0;
1973
1974 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1975 for(;;);
1976 }
1977
1978 static void prepare_lazy(struct dso *p)
1979 {
1980 size_t dyn[DYN_CNT], n, flags1=0;
1981 decode_vec(p->dynv, dyn, DYN_CNT);
1982 search_vec(p->dynv, &flags1, DT_FLAGS_1);
1983 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1984 return;
1985 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1986 if (NEED_MIPS_GOT_RELOCS) {
1987 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1988 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1989 n += i-j;
1990 }
1991 p->lazy = calloc(n, 3*sizeof(size_t));
1992 if (!p->lazy) {
1993 error("Error preparing lazy relocation for %s: %m", p->name);
1994 longjmp(*rtld_fail, 1);
1995 }
1996 p->lazy_next = lazy_head;
1997 lazy_head = p;
1998 }
1999
2000 void *dlopen(const char *file, int mode)
2001 {
2002 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
2003 struct tls_module *orig_tls_tail;
2004 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
2005 size_t i;
2006 int cs;
2007 jmp_buf jb;
2008 struct dso **volatile ctor_queue = 0;
2009
2010 if (!file) return head;
2011
2012 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
2013 pthread_rwlock_wrlock(&lock);
2014 __inhibit_ptc();
2015
2016 debug.state = RT_ADD;
2017 _dl_debug_state();
2018
2019 p = 0;
2020 if (shutting_down) {
2021 error("Cannot dlopen while program is exiting.");
2022 goto end;
2023 }
2024 orig_tls_tail = tls_tail;
2025 orig_tls_cnt = tls_cnt;
2026 orig_tls_offset = tls_offset;
2027 orig_tls_align = tls_align;
2028 orig_lazy_head = lazy_head;
2029 orig_syms_tail = syms_tail;
2030 orig_tail = tail;
2031 noload = mode & RTLD_NOLOAD;
2032
2033 rtld_fail = &jb;
2034 if (setjmp(*rtld_fail)) {
2035 /* Clean up anything new that was (partially) loaded */
2036 revert_syms(orig_syms_tail);
2037 for (p=orig_tail->next; p; p=next) {
2038 next = p->next;
2039 while (p->td_index) {
2040 void *tmp = p->td_index->next;
2041 free(p->td_index);
2042 p->td_index = tmp;
2043 }
2044 free(p->funcdescs);
2045 if (p->rpath != p->rpath_orig)
2046 free(p->rpath);
2047 free(p->deps);
2048 unmap_library(p);
2049 free(p);
2050 }
2051 free(ctor_queue);
2052 ctor_queue = 0;
2053 if (!orig_tls_tail) libc.tls_head = 0;
2054 tls_tail = orig_tls_tail;
2055 if (tls_tail) tls_tail->next = 0;
2056 tls_cnt = orig_tls_cnt;
2057 tls_offset = orig_tls_offset;
2058 tls_align = orig_tls_align;
2059 lazy_head = orig_lazy_head;
2060 tail = orig_tail;
2061 tail->next = 0;
2062 p = 0;
2063 goto end;
2064 } else p = load_library(file, head);
2065
2066 if (!p) {
2067 error(noload ?
2068 "Library %s is not already loaded" :
2069 "Error loading shared library %s: %m",
2070 file);
2071 goto end;
2072 }
2073
2074 /* First load handling */
2075 load_deps(p);
2076 extend_bfs_deps(p);
2077 pthread_mutex_lock(&init_fini_lock);
2078 int constructed = p->constructed;
2079 pthread_mutex_unlock(&init_fini_lock);
2080 if (!constructed) ctor_queue = queue_ctors(p);
2081 if (!p->relocated && (mode & RTLD_LAZY)) {
2082 prepare_lazy(p);
2083 for (i=0; p->deps[i]; i++)
2084 if (!p->deps[i]->relocated)
2085 prepare_lazy(p->deps[i]);
2086 }
2087 if (!p->relocated || (mode & RTLD_GLOBAL)) {
2088 /* Make new symbols global, at least temporarily, so we can do
2089 * relocations. If not RTLD_GLOBAL, this is reverted below. */
2090 add_syms(p);
2091 for (i=0; p->deps[i]; i++)
2092 add_syms(p->deps[i]);
2093 }
2094 if (!p->relocated) {
2095 reloc_all(p);
2096 }
2097
2098 /* If RTLD_GLOBAL was not specified, undo any new additions
2099 * to the global symbol table. This is a nop if the library was
2100 * previously loaded and already global. */
2101 if (!(mode & RTLD_GLOBAL))
2102 revert_syms(orig_syms_tail);
2103
2104 /* Processing of deferred lazy relocations must not happen until
2105 * the new libraries are committed; otherwise we could end up with
2106 * relocations resolved to symbol definitions that get removed. */
2107 redo_lazy_relocs();
2108
2109 update_tls_size();
2110 if (tls_cnt != orig_tls_cnt)
2111 install_new_tls();
2112 orig_tail = tail;
2113 end:
2114 debug.state = RT_CONSISTENT;
2115 _dl_debug_state();
2116 __release_ptc();
2117 if (p) gencnt++;
2118 pthread_rwlock_unlock(&lock);
2119 if (ctor_queue) {
2120 do_init_fini(ctor_queue);
2121 free(ctor_queue);
2122 }
2123 pthread_setcancelstate(cs, 0);
2124 return p;
2125 }
2126
2127 hidden int __dl_invalid_handle(void *h)
2128 {
2129 struct dso *p;
2130 for (p=head; p; p=p->next) if (h==p) return 0;
2131 error("Invalid library handle %p", (void *)h);
2132 return 1;
2133 }
2134
2135 static void *addr2dso(size_t a)
2136 {
2137 struct dso *p;
2138 size_t i;
2139 if (DL_FDPIC) for (p=head; p; p=p->next) {
2140 i = count_syms(p);
2141 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
2142 return p;
2143 }
2144 for (p=head; p; p=p->next) {
2145 if (DL_FDPIC && p->loadmap) {
2146 for (i=0; i<p->loadmap->nsegs; i++) {
2147 if (a-p->loadmap->segs[i].p_vaddr
2148 < p->loadmap->segs[i].p_memsz)
2149 return p;
2150 }
2151 } else {
2152 Phdr *ph = p->phdr;
2153 size_t phcnt = p->phnum;
2154 size_t entsz = p->phentsize;
2155 size_t base = (size_t)p->base;
2156 for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
2157 if (ph->p_type != PT_LOAD) continue;
2158 if (a-base-ph->p_vaddr < ph->p_memsz)
2159 return p;
2160 }
2161 if (a-(size_t)p->map < p->map_len)
2162 return 0;
2163 }
2164 }
2165 return 0;
2166 }
2167
2168 static void *do_dlsym(struct dso *p, const char *s, void *ra)
2169 {
2170 int use_deps = 0;
2171 if (p == head || p == RTLD_DEFAULT) {
2172 p = head;
2173 } else if (p == RTLD_NEXT) {
2174 p = addr2dso((size_t)ra);
2175 if (!p) p=head;
2176 p = p->next;
2177 } else if (__dl_invalid_handle(p)) {
2178 return 0;
2179 } else
2180 use_deps = 1;
2181 struct symdef def = find_sym2(p, s, 0, use_deps);
2182 if (!def.sym) {
2183 error("Symbol not found: %s", s);
2184 return 0;
2185 }
2186 if ((def.sym->st_info&0xf) == STT_TLS)
2187 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
2188 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
2189 return def.dso->funcdescs + (def.sym - def.dso->syms);
2190 return laddr(def.dso, def.sym->st_value);
2191 }
2192
2193 int dladdr(const void *addr_arg, Dl_info *info)
2194 {
2195 size_t addr = (size_t)addr_arg;
2196 struct dso *p;
2197 Sym *sym, *bestsym;
2198 uint32_t nsym;
2199 char *strings;
2200 size_t best = 0;
2201 size_t besterr = -1;
2202
2203 pthread_rwlock_rdlock(&lock);
2204 p = addr2dso(addr);
2205 pthread_rwlock_unlock(&lock);
2206
2207 if (!p) return 0;
2208
2209 sym = p->syms;
2210 strings = p->strings;
2211 nsym = count_syms(p);
2212
2213 if (DL_FDPIC) {
2214 size_t idx = (addr-(size_t)p->funcdescs)
2215 / sizeof(*p->funcdescs);
2216 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
2217 best = (size_t)(p->funcdescs + idx);
2218 bestsym = sym + idx;
2219 besterr = 0;
2220 }
2221 }
2222
2223 if (!best) for (; nsym; nsym--, sym++) {
2224 if (sym->st_value
2225 && (1<<(sym->st_info&0xf) & OK_TYPES)
2226 && (1<<(sym->st_info>>4) & OK_BINDS)) {
2227 size_t symaddr = (size_t)laddr(p, sym->st_value);
2228 if (symaddr > addr || symaddr <= best)
2229 continue;
2230 best = symaddr;
2231 bestsym = sym;
2232 besterr = addr - symaddr;
2233 if (addr == symaddr)
2234 break;
2235 }
2236 }
2237
2238 if (best && besterr > bestsym->st_size-1) {
2239 best = 0;
2240 bestsym = 0;
2241 }
2242
2243 info->dli_fname = p->name;
2244 info->dli_fbase = p->map;
2245
2246 if (!best) {
2247 info->dli_sname = 0;
2248 info->dli_saddr = 0;
2249 return 1;
2250 }
2251
2252 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2253 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2254 info->dli_sname = strings + bestsym->st_name;
2255 info->dli_saddr = (void *)best;
2256
2257 return 1;
2258 }
2259
2260 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2261 {
2262 void *res;
2263 pthread_rwlock_rdlock(&lock);
2264 res = do_dlsym(p, s, ra);
2265 pthread_rwlock_unlock(&lock);
2266 return res;
2267 }
2268
2269 hidden void *__dlsym_redir_time64(void *restrict p, const char *restrict s, void *restrict ra)
2270 {
2271 #if _REDIR_TIME64
2272 const char *suffix, *suffix2 = "";
2273 char redir[36];
2274
2275 /* Map the symbol name to a time64 version of itself according to the
2276 * pattern used for naming the redirected time64 symbols. */
2277 size_t l = strnlen(s, sizeof redir);
2278 if (l<4 || l==sizeof redir) goto no_redir;
2279 if (s[l-2]=='_' && s[l-1]=='r') {
2280 l -= 2;
2281 suffix2 = s+l;
2282 }
2283 if (l<4) goto no_redir;
2284 if (!strcmp(s+l-4, "time")) suffix = "64";
2285 else suffix = "_time64";
2286
2287 /* Use the presence of the remapped symbol name in libc to determine
2288 * whether it's one that requires time64 redirection; replace if so. */
2289 snprintf(redir, sizeof redir, "__%.*s%s%s", (int)l, s, suffix, suffix2);
2290 if (find_sym(&ldso, redir, 1).sym) s = redir;
2291 no_redir:
2292 #endif
2293 return __dlsym(p, s, ra);
2294 }
2295
2296 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2297 {
2298 struct dso *current;
2299 struct dl_phdr_info info;
2300 int ret = 0;
2301 for(current = head; current;) {
2302 info.dlpi_addr = (uintptr_t)current->base;
2303 info.dlpi_name = current->name;
2304 info.dlpi_phdr = current->phdr;
2305 info.dlpi_phnum = current->phnum;
2306 info.dlpi_adds = gencnt;
2307 info.dlpi_subs = 0;
2308 info.dlpi_tls_modid = current->tls_id;
2309 info.dlpi_tls_data = current->tls.image;
2310
2311 ret = (callback)(&info, sizeof (info), data);
2312
2313 if (ret != 0) break;
2314
2315 pthread_rwlock_rdlock(&lock);
2316 current = current->next;
2317 pthread_rwlock_unlock(&lock);
2318 }
2319 return ret;
2320 }
2321
2322 static void error(const char *fmt, ...)
2323 {
2324 va_list ap;
2325 va_start(ap, fmt);
2326 if (!runtime) {
2327 vdprintf(2, fmt, ap);
2328 dprintf(2, "\n");
2329 ldso_fail = 1;
2330 va_end(ap);
2331 return;
2332 }
2333 __dl_vseterr(fmt, ap);
2334 va_end(ap);
2335 }
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