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make arch __set_thread_area backends hidden
[musl.git] / ldso / dynlink.c
blob7200c8178ec114a8efd2217f885f699cfbc3acc5
1 #define _GNU_SOURCE
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <stdarg.h>
5 #include <stddef.h>
6 #include <string.h>
7 #include <unistd.h>
8 #include <stdint.h>
9 #include <elf.h>
10 #include <sys/mman.h>
11 #include <limits.h>
12 #include <fcntl.h>
13 #include <sys/stat.h>
14 #include <errno.h>
15 #include <link.h>
16 #include <setjmp.h>
17 #include <pthread.h>
18 #include <ctype.h>
19 #include <dlfcn.h>
20 #include "pthread_impl.h"
21 #include "libc.h"
22 #include "dynlink.h"
23 #include "malloc_impl.h"
24
25 static void error(const char *, ...);
26
27 #define MAXP2(a,b) (-(-(a)&-(b)))
28 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
29
30 struct debug {
31 int ver;
32 void *head;
33 void (*bp)(void);
34 int state;
35 void *base;
36 };
37
38 struct td_index {
39 size_t args[2];
40 struct td_index *next;
41 };
42
43 struct dso {
44 #if DL_FDPIC
45 struct fdpic_loadmap *loadmap;
46 #else
47 unsigned char *base;
48 #endif
49 char *name;
50 size_t *dynv;
51 struct dso *next, *prev;
52
53 Phdr *phdr;
54 int phnum;
55 size_t phentsize;
56 Sym *syms;
57 Elf_Symndx *hashtab;
58 uint32_t *ghashtab;
59 int16_t *versym;
60 char *strings;
61 struct dso *syms_next, *lazy_next;
62 size_t *lazy, lazy_cnt;
63 unsigned char *map;
64 size_t map_len;
65 dev_t dev;
66 ino_t ino;
67 char relocated;
68 char constructed;
69 char kernel_mapped;
70 struct dso **deps, *needed_by;
71 char *rpath_orig, *rpath;
72 struct tls_module tls;
73 size_t tls_id;
74 size_t relro_start, relro_end;
75 void **new_dtv;
76 unsigned char *new_tls;
77 volatile int new_dtv_idx, new_tls_idx;
78 struct td_index *td_index;
79 struct dso *fini_next;
80 char *shortname;
81 #if DL_FDPIC
82 unsigned char *base;
83 #else
84 struct fdpic_loadmap *loadmap;
85 #endif
86 struct funcdesc {
87 void *addr;
88 size_t *got;
89 } *funcdescs;
90 size_t *got;
91 char buf[];
92 };
93
94 struct symdef {
95 Sym *sym;
96 struct dso *dso;
97 };
98
99 void __init_libc(char **, char *);
100
101 static struct builtin_tls {
102 char c;
103 struct pthread pt;
104 void *space[16];
105 } builtin_tls[1];
106 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
107
108 #define ADDEND_LIMIT 4096
109 static size_t *saved_addends, *apply_addends_to;
110
111 static struct dso ldso;
112 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
113 static char *env_path, *sys_path;
114 static unsigned long long gencnt;
115 static int runtime;
116 static int ldd_mode;
117 static int ldso_fail;
118 static int noload;
119 static jmp_buf *rtld_fail;
120 static pthread_rwlock_t lock;
121 static struct debug debug;
122 static struct tls_module *tls_tail;
123 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
124 static size_t static_tls_cnt;
125 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
126 static struct fdpic_loadmap *app_loadmap;
127 static struct fdpic_dummy_loadmap app_dummy_loadmap;
128 static struct dso *const nodeps_dummy;
129
130 struct debug *_dl_debug_addr = &debug;
131
132 extern hidden int __malloc_replaced;
133
134 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
135
136 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
137
138 weak_alias(__init_array_start, __init_array_end);
139 weak_alias(__fini_array_start, __fini_array_end);
140
141 static int dl_strcmp(const char *l, const char *r)
142 {
143 for (; *l==*r && *l; l++, r++);
144 return *(unsigned char *)l - *(unsigned char *)r;
145 }
146 #define strcmp(l,r) dl_strcmp(l,r)
147
148 /* Compute load address for a virtual address in a given dso. */
149 #if DL_FDPIC
150 static void *laddr(const struct dso *p, size_t v)
151 {
152 size_t j=0;
153 if (!p->loadmap) return p->base + v;
154 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
155 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
156 }
157 static void *laddr_pg(const struct dso *p, size_t v)
158 {
159 size_t j=0;
160 size_t pgsz = PAGE_SIZE;
161 if (!p->loadmap) return p->base + v;
162 for (j=0; ; j++) {
163 size_t a = p->loadmap->segs[j].p_vaddr;
164 size_t b = a + p->loadmap->segs[j].p_memsz;
165 a &= -pgsz;
166 b += pgsz-1;
167 b &= -pgsz;
168 if (v-a<b-a) break;
169 }
170 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
171 }
172 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
173 laddr(p, v), (p)->got })
174 #else
175 #define laddr(p, v) (void *)((p)->base + (v))
176 #define laddr_pg(p, v) laddr(p, v)
177 #define fpaddr(p, v) ((void (*)())laddr(p, v))
178 #endif
179
180 static void decode_vec(size_t *v, size_t *a, size_t cnt)
181 {
182 size_t i;
183 for (i=0; i<cnt; i++) a[i] = 0;
184 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
185 a[0] |= 1UL<<v[0];
186 a[v[0]] = v[1];
187 }
188 }
189
190 static int search_vec(size_t *v, size_t *r, size_t key)
191 {
192 for (; v[0]!=key; v+=2)
193 if (!v[0]) return 0;
194 *r = v[1];
195 return 1;
196 }
197
198 static uint32_t sysv_hash(const char *s0)
199 {
200 const unsigned char *s = (void *)s0;
201 uint_fast32_t h = 0;
202 while (*s) {
203 h = 16*h + *s++;
204 h ^= h>>24 & 0xf0;
205 }
206 return h & 0xfffffff;
207 }
208
209 static uint32_t gnu_hash(const char *s0)
210 {
211 const unsigned char *s = (void *)s0;
212 uint_fast32_t h = 5381;
213 for (; *s; s++)
214 h += h*32 + *s;
215 return h;
216 }
217
218 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
219 {
220 size_t i;
221 Sym *syms = dso->syms;
222 Elf_Symndx *hashtab = dso->hashtab;
223 char *strings = dso->strings;
224 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
225 if ((!dso->versym || dso->versym[i] >= 0)
226 && (!strcmp(s, strings+syms[i].st_name)))
227 return syms+i;
228 }
229 return 0;
230 }
231
232 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
233 {
234 uint32_t nbuckets = hashtab[0];
235 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
236 uint32_t i = buckets[h1 % nbuckets];
237
238 if (!i) return 0;
239
240 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
241
242 for (h1 |= 1; ; i++) {
243 uint32_t h2 = *hashval++;
244 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
245 && !strcmp(s, dso->strings + dso->syms[i].st_name))
246 return dso->syms+i;
247 if (h2 & 1) break;
248 }
249
250 return 0;
251 }
252
253 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
254 {
255 const size_t *bloomwords = (const void *)(hashtab+4);
256 size_t f = bloomwords[fofs & (hashtab[2]-1)];
257 if (!(f & fmask)) return 0;
258
259 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
260 if (!(f & 1)) return 0;
261
262 return gnu_lookup(h1, hashtab, dso, s);
263 }
264
265 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
266 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
267
268 #ifndef ARCH_SYM_REJECT_UND
269 #define ARCH_SYM_REJECT_UND(s) 0
270 #endif
271
272 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
273 {
274 uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
275 size_t ghm = 1ul << gh % (8*sizeof(size_t));
276 struct symdef def = {0};
277 for (; dso; dso=dso->syms_next) {
278 Sym *sym;
279 if ((ght = dso->ghashtab)) {
280 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
281 } else {
282 if (!h) h = sysv_hash(s);
283 sym = sysv_lookup(s, h, dso);
284 }
285 if (!sym) continue;
286 if (!sym->st_shndx)
287 if (need_def || (sym->st_info&0xf) == STT_TLS
288 || ARCH_SYM_REJECT_UND(sym))
289 continue;
290 if (!sym->st_value)
291 if ((sym->st_info&0xf) != STT_TLS)
292 continue;
293 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
294 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
295 def.sym = sym;
296 def.dso = dso;
297 break;
298 }
299 return def;
300 }
301
302 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
303 {
304 unsigned char *base = dso->base;
305 Sym *syms = dso->syms;
306 char *strings = dso->strings;
307 Sym *sym;
308 const char *name;
309 void *ctx;
310 int type;
311 int sym_index;
312 struct symdef def;
313 size_t *reloc_addr;
314 size_t sym_val;
315 size_t tls_val;
316 size_t addend;
317 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
318
319 if (dso == &ldso) {
320 /* Only ldso's REL table needs addend saving/reuse. */
321 if (rel == apply_addends_to)
322 reuse_addends = 1;
323 skip_relative = 1;
324 }
325
326 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
327 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
328 type = R_TYPE(rel[1]);
329 if (type == REL_NONE) continue;
330 reloc_addr = laddr(dso, rel[0]);
331
332 if (stride > 2) {
333 addend = rel[2];
334 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
335 addend = 0;
336 } else if (reuse_addends) {
337 /* Save original addend in stage 2 where the dso
338 * chain consists of just ldso; otherwise read back
339 * saved addend since the inline one was clobbered. */
340 if (head==&ldso)
341 saved_addends[save_slot] = *reloc_addr;
342 addend = saved_addends[save_slot++];
343 } else {
344 addend = *reloc_addr;
345 }
346
347 sym_index = R_SYM(rel[1]);
348 if (sym_index) {
349 sym = syms + sym_index;
350 name = strings + sym->st_name;
351 ctx = type==REL_COPY ? head->syms_next : head;
352 def = (sym->st_info&0xf) == STT_SECTION
353 ? (struct symdef){ .dso = dso, .sym = sym }
354 : find_sym(ctx, name, type==REL_PLT);
355 if (!def.sym && (sym->st_shndx != SHN_UNDEF
356 || sym->st_info>>4 != STB_WEAK)) {
357 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
358 dso->lazy[3*dso->lazy_cnt+0] = rel[0];
359 dso->lazy[3*dso->lazy_cnt+1] = rel[1];
360 dso->lazy[3*dso->lazy_cnt+2] = addend;
361 dso->lazy_cnt++;
362 continue;
363 }
364 error("Error relocating %s: %s: symbol not found",
365 dso->name, name);
366 if (runtime) longjmp(*rtld_fail, 1);
367 continue;
368 }
369 } else {
370 sym = 0;
371 def.sym = 0;
372 def.dso = dso;
373 }
374
375 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
376 tls_val = def.sym ? def.sym->st_value : 0;
377
378 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
379 && runtime && def.dso->tls_id > static_tls_cnt) {
380 error("Error relocating %s: %s: initial-exec TLS "
381 "resolves to dynamic definition in %s",
382 dso->name, name, def.dso->name);
383 longjmp(*rtld_fail, 1);
384 }
385
386 switch(type) {
387 case REL_NONE:
388 break;
389 case REL_OFFSET:
390 addend -= (size_t)reloc_addr;
391 case REL_SYMBOLIC:
392 case REL_GOT:
393 case REL_PLT:
394 *reloc_addr = sym_val + addend;
395 break;
396 case REL_RELATIVE:
397 *reloc_addr = (size_t)base + addend;
398 break;
399 case REL_SYM_OR_REL:
400 if (sym) *reloc_addr = sym_val + addend;
401 else *reloc_addr = (size_t)base + addend;
402 break;
403 case REL_COPY:
404 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
405 break;
406 case REL_OFFSET32:
407 *(uint32_t *)reloc_addr = sym_val + addend
408 - (size_t)reloc_addr;
409 break;
410 case REL_FUNCDESC:
411 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
412 + (def.sym - def.dso->syms)) : 0;
413 break;
414 case REL_FUNCDESC_VAL:
415 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
416 else *reloc_addr = sym_val;
417 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
418 break;
419 case REL_DTPMOD:
420 *reloc_addr = def.dso->tls_id;
421 break;
422 case REL_DTPOFF:
423 *reloc_addr = tls_val + addend - DTP_OFFSET;
424 break;
425 #ifdef TLS_ABOVE_TP
426 case REL_TPOFF:
427 *reloc_addr = tls_val + def.dso->tls.offset + TPOFF_K + addend;
428 break;
429 #else
430 case REL_TPOFF:
431 *reloc_addr = tls_val - def.dso->tls.offset + addend;
432 break;
433 case REL_TPOFF_NEG:
434 *reloc_addr = def.dso->tls.offset - tls_val + addend;
435 break;
436 #endif
437 case REL_TLSDESC:
438 if (stride<3) addend = reloc_addr[1];
439 if (runtime && def.dso->tls_id > static_tls_cnt) {
440 struct td_index *new = malloc(sizeof *new);
441 if (!new) {
442 error(
443 "Error relocating %s: cannot allocate TLSDESC for %s",
444 dso->name, sym ? name : "(local)" );
445 longjmp(*rtld_fail, 1);
446 }
447 new->next = dso->td_index;
448 dso->td_index = new;
449 new->args[0] = def.dso->tls_id;
450 new->args[1] = tls_val + addend;
451 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
452 reloc_addr[1] = (size_t)new;
453 } else {
454 reloc_addr[0] = (size_t)__tlsdesc_static;
455 #ifdef TLS_ABOVE_TP
456 reloc_addr[1] = tls_val + def.dso->tls.offset
457 + TPOFF_K + addend;
458 #else
459 reloc_addr[1] = tls_val - def.dso->tls.offset
460 + addend;
461 #endif
462 }
463 break;
464 default:
465 error("Error relocating %s: unsupported relocation type %d",
466 dso->name, type);
467 if (runtime) longjmp(*rtld_fail, 1);
468 continue;
469 }
470 }
471 }
472
473 static void redo_lazy_relocs()
474 {
475 struct dso *p = lazy_head, *next;
476 lazy_head = 0;
477 for (; p; p=next) {
478 next = p->lazy_next;
479 size_t size = p->lazy_cnt*3*sizeof(size_t);
480 p->lazy_cnt = 0;
481 do_relocs(p, p->lazy, size, 3);
482 if (p->lazy_cnt) {
483 p->lazy_next = lazy_head;
484 lazy_head = p;
485 } else {
486 free(p->lazy);
487 p->lazy = 0;
488 p->lazy_next = 0;
489 }
490 }
491 }
492
493 /* A huge hack: to make up for the wastefulness of shared libraries
494 * needing at least a page of dirty memory even if they have no global
495 * data, we reclaim the gaps at the beginning and end of writable maps
496 * and "donate" them to the heap. */
497
498 static void reclaim(struct dso *dso, size_t start, size_t end)
499 {
500 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
501 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
502 if (start >= end) return;
503 char *base = laddr_pg(dso, start);
504 __malloc_donate(base, base+(end-start));
505 }
506
507 static void reclaim_gaps(struct dso *dso)
508 {
509 Phdr *ph = dso->phdr;
510 size_t phcnt = dso->phnum;
511
512 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
513 if (ph->p_type!=PT_LOAD) continue;
514 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
515 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
516 reclaim(dso, ph->p_vaddr+ph->p_memsz,
517 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
518 }
519 }
520
521 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
522 {
523 static int no_map_fixed;
524 char *q;
525 if (!no_map_fixed) {
526 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
527 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
528 return q;
529 no_map_fixed = 1;
530 }
531 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
532 if (flags & MAP_ANONYMOUS) {
533 memset(p, 0, n);
534 return p;
535 }
536 ssize_t r;
537 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
538 for (q=p; n; q+=r, off+=r, n-=r) {
539 r = read(fd, q, n);
540 if (r < 0 && errno != EINTR) return MAP_FAILED;
541 if (!r) {
542 memset(q, 0, n);
543 break;
544 }
545 }
546 return p;
547 }
548
549 static void unmap_library(struct dso *dso)
550 {
551 if (dso->loadmap) {
552 size_t i;
553 for (i=0; i<dso->loadmap->nsegs; i++) {
554 if (!dso->loadmap->segs[i].p_memsz)
555 continue;
556 munmap((void *)dso->loadmap->segs[i].addr,
557 dso->loadmap->segs[i].p_memsz);
558 }
559 free(dso->loadmap);
560 } else if (dso->map && dso->map_len) {
561 munmap(dso->map, dso->map_len);
562 }
563 }
564
565 static void *map_library(int fd, struct dso *dso)
566 {
567 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
568 void *allocated_buf=0;
569 size_t phsize;
570 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
571 size_t this_min, this_max;
572 size_t nsegs = 0;
573 off_t off_start;
574 Ehdr *eh;
575 Phdr *ph, *ph0;
576 unsigned prot;
577 unsigned char *map=MAP_FAILED, *base;
578 size_t dyn=0;
579 size_t tls_image=0;
580 size_t i;
581
582 ssize_t l = read(fd, buf, sizeof buf);
583 eh = buf;
584 if (l<0) return 0;
585 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
586 goto noexec;
587 phsize = eh->e_phentsize * eh->e_phnum;
588 if (phsize > sizeof buf - sizeof *eh) {
589 allocated_buf = malloc(phsize);
590 if (!allocated_buf) return 0;
591 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
592 if (l < 0) goto error;
593 if (l != phsize) goto noexec;
594 ph = ph0 = allocated_buf;
595 } else if (eh->e_phoff + phsize > l) {
596 l = pread(fd, buf+1, phsize, eh->e_phoff);
597 if (l < 0) goto error;
598 if (l != phsize) goto noexec;
599 ph = ph0 = (void *)(buf + 1);
600 } else {
601 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
602 }
603 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
604 if (ph->p_type == PT_DYNAMIC) {
605 dyn = ph->p_vaddr;
606 } else if (ph->p_type == PT_TLS) {
607 tls_image = ph->p_vaddr;
608 dso->tls.align = ph->p_align;
609 dso->tls.len = ph->p_filesz;
610 dso->tls.size = ph->p_memsz;
611 } else if (ph->p_type == PT_GNU_RELRO) {
612 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
613 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
614 }
615 if (ph->p_type != PT_LOAD) continue;
616 nsegs++;
617 if (ph->p_vaddr < addr_min) {
618 addr_min = ph->p_vaddr;
619 off_start = ph->p_offset;
620 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
621 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
622 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
623 }
624 if (ph->p_vaddr+ph->p_memsz > addr_max) {
625 addr_max = ph->p_vaddr+ph->p_memsz;
626 }
627 }
628 if (!dyn) goto noexec;
629 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
630 dso->loadmap = calloc(1, sizeof *dso->loadmap
631 + nsegs * sizeof *dso->loadmap->segs);
632 if (!dso->loadmap) goto error;
633 dso->loadmap->nsegs = nsegs;
634 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
635 if (ph->p_type != PT_LOAD) continue;
636 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
637 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
638 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
639 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
640 prot, MAP_PRIVATE,
641 fd, ph->p_offset & -PAGE_SIZE);
642 if (map == MAP_FAILED) {
643 unmap_library(dso);
644 goto error;
645 }
646 dso->loadmap->segs[i].addr = (size_t)map +
647 (ph->p_vaddr & PAGE_SIZE-1);
648 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
649 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
650 i++;
651 if (prot & PROT_WRITE) {
652 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
653 + ph->p_filesz;
654 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
655 size_t pgend = brk + ph->p_memsz - ph->p_filesz
656 + PAGE_SIZE-1 & -PAGE_SIZE;
657 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
658 pgend-pgbrk, prot,
659 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
660 -1, off_start) == MAP_FAILED)
661 goto error;
662 memset(map + brk, 0, pgbrk-brk);
663 }
664 }
665 map = (void *)dso->loadmap->segs[0].addr;
666 map_len = 0;
667 goto done_mapping;
668 }
669 addr_max += PAGE_SIZE-1;
670 addr_max &= -PAGE_SIZE;
671 addr_min &= -PAGE_SIZE;
672 off_start &= -PAGE_SIZE;
673 map_len = addr_max - addr_min + off_start;
674 /* The first time, we map too much, possibly even more than
675 * the length of the file. This is okay because we will not
676 * use the invalid part; we just need to reserve the right
677 * amount of virtual address space to map over later. */
678 map = DL_NOMMU_SUPPORT
679 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
680 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
681 : mmap((void *)addr_min, map_len, prot,
682 MAP_PRIVATE, fd, off_start);
683 if (map==MAP_FAILED) goto error;
684 dso->map = map;
685 dso->map_len = map_len;
686 /* If the loaded file is not relocatable and the requested address is
687 * not available, then the load operation must fail. */
688 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
689 errno = EBUSY;
690 goto error;
691 }
692 base = map - addr_min;
693 dso->phdr = 0;
694 dso->phnum = 0;
695 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
696 if (ph->p_type != PT_LOAD) continue;
697 /* Check if the programs headers are in this load segment, and
698 * if so, record the address for use by dl_iterate_phdr. */
699 if (!dso->phdr && eh->e_phoff >= ph->p_offset
700 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
701 dso->phdr = (void *)(base + ph->p_vaddr
702 + (eh->e_phoff-ph->p_offset));
703 dso->phnum = eh->e_phnum;
704 dso->phentsize = eh->e_phentsize;
705 }
706 this_min = ph->p_vaddr & -PAGE_SIZE;
707 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
708 off_start = ph->p_offset & -PAGE_SIZE;
709 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
710 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
711 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
712 /* Reuse the existing mapping for the lowest-address LOAD */
713 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
714 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
715 goto error;
716 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
717 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
718 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
719 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
720 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)
721 goto error;
722 }
723 }
724 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
725 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
726 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
727 && errno != ENOSYS)
728 goto error;
729 break;
730 }
731 done_mapping:
732 dso->base = base;
733 dso->dynv = laddr(dso, dyn);
734 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
735 free(allocated_buf);
736 return map;
737 noexec:
738 errno = ENOEXEC;
739 error:
740 if (map!=MAP_FAILED) unmap_library(dso);
741 free(allocated_buf);
742 return 0;
743 }
744
745 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
746 {
747 size_t l;
748 int fd;
749 for (;;) {
750 s += strspn(s, ":\n");
751 l = strcspn(s, ":\n");
752 if (l-1 >= INT_MAX) return -1;
753 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
754 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
755 switch (errno) {
756 case ENOENT:
757 case ENOTDIR:
758 case EACCES:
759 case ENAMETOOLONG:
760 break;
761 default:
762 /* Any negative value but -1 will inhibit
763 * futher path search. */
764 return -2;
765 }
766 }
767 s += l;
768 }
769 }
770
771 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
772 {
773 size_t n, l;
774 const char *s, *t, *origin;
775 char *d;
776 if (p->rpath || !p->rpath_orig) return 0;
777 if (!strchr(p->rpath_orig, '$')) {
778 p->rpath = p->rpath_orig;
779 return 0;
780 }
781 n = 0;
782 s = p->rpath_orig;
783 while ((t=strchr(s, '$'))) {
784 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
785 return 0;
786 s = t+1;
787 n++;
788 }
789 if (n > SSIZE_MAX/PATH_MAX) return 0;
790
791 if (p->kernel_mapped) {
792 /* $ORIGIN searches cannot be performed for the main program
793 * when it is suid/sgid/AT_SECURE. This is because the
794 * pathname is under the control of the caller of execve.
795 * For libraries, however, $ORIGIN can be processed safely
796 * since the library's pathname came from a trusted source
797 * (either system paths or a call to dlopen). */
798 if (libc.secure)
799 return 0;
800 l = readlink("/proc/self/exe", buf, buf_size);
801 if (l == -1) switch (errno) {
802 case ENOENT:
803 case ENOTDIR:
804 case EACCES:
805 break;
806 default:
807 return -1;
808 }
809 if (l >= buf_size)
810 return 0;
811 buf[l] = 0;
812 origin = buf;
813 } else {
814 origin = p->name;
815 }
816 t = strrchr(origin, '/');
817 if (t) {
818 l = t-origin;
819 } else {
820 /* Normally p->name will always be an absolute or relative
821 * pathname containing at least one '/' character, but in the
822 * case where ldso was invoked as a command to execute a
823 * program in the working directory, app.name may not. Fix. */
824 origin = ".";
825 l = 1;
826 }
827 /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
828 if (libc.secure && *origin != '/')
829 return 0;
830 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
831 if (!p->rpath) return -1;
832
833 d = p->rpath;
834 s = p->rpath_orig;
835 while ((t=strchr(s, '$'))) {
836 memcpy(d, s, t-s);
837 d += t-s;
838 memcpy(d, origin, l);
839 d += l;
840 /* It was determined previously that the '$' is followed
841 * either by "ORIGIN" or "{ORIGIN}". */
842 s = t + 7 + 2*(t[1]=='{');
843 }
844 strcpy(d, s);
845 return 0;
846 }
847
848 static void decode_dyn(struct dso *p)
849 {
850 size_t dyn[DYN_CNT];
851 decode_vec(p->dynv, dyn, DYN_CNT);
852 p->syms = laddr(p, dyn[DT_SYMTAB]);
853 p->strings = laddr(p, dyn[DT_STRTAB]);
854 if (dyn[0]&(1<<DT_HASH))
855 p->hashtab = laddr(p, dyn[DT_HASH]);
856 if (dyn[0]&(1<<DT_RPATH))
857 p->rpath_orig = p->strings + dyn[DT_RPATH];
858 if (dyn[0]&(1<<DT_RUNPATH))
859 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
860 if (dyn[0]&(1<<DT_PLTGOT))
861 p->got = laddr(p, dyn[DT_PLTGOT]);
862 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
863 p->ghashtab = laddr(p, *dyn);
864 if (search_vec(p->dynv, dyn, DT_VERSYM))
865 p->versym = laddr(p, *dyn);
866 }
867
868 static size_t count_syms(struct dso *p)
869 {
870 if (p->hashtab) return p->hashtab[1];
871
872 size_t nsym, i;
873 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
874 uint32_t *hashval;
875 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
876 if (buckets[i] > nsym)
877 nsym = buckets[i];
878 }
879 if (nsym) {
880 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
881 do nsym++;
882 while (!(*hashval++ & 1));
883 }
884 return nsym;
885 }
886
887 static void *dl_mmap(size_t n)
888 {
889 void *p;
890 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
891 #ifdef SYS_mmap2
892 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
893 #else
894 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
895 #endif
896 return p == MAP_FAILED ? 0 : p;
897 }
898
899 static void makefuncdescs(struct dso *p)
900 {
901 static int self_done;
902 size_t nsym = count_syms(p);
903 size_t i, size = nsym * sizeof(*p->funcdescs);
904
905 if (!self_done) {
906 p->funcdescs = dl_mmap(size);
907 self_done = 1;
908 } else {
909 p->funcdescs = malloc(size);
910 }
911 if (!p->funcdescs) {
912 if (!runtime) a_crash();
913 error("Error allocating function descriptors for %s", p->name);
914 longjmp(*rtld_fail, 1);
915 }
916 for (i=0; i<nsym; i++) {
917 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
918 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
919 p->funcdescs[i].got = p->got;
920 } else {
921 p->funcdescs[i].addr = 0;
922 p->funcdescs[i].got = 0;
923 }
924 }
925 }
926
927 static struct dso *load_library(const char *name, struct dso *needed_by)
928 {
929 char buf[2*NAME_MAX+2];
930 const char *pathname;
931 unsigned char *map;
932 struct dso *p, temp_dso = {0};
933 int fd;
934 struct stat st;
935 size_t alloc_size;
936 int n_th = 0;
937 int is_self = 0;
938
939 if (!*name) {
940 errno = EINVAL;
941 return 0;
942 }
943
944 /* Catch and block attempts to reload the implementation itself */
945 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
946 static const char reserved[] =
947 "c.pthread.rt.m.dl.util.xnet.";
948 const char *rp, *next;
949 for (rp=reserved; *rp; rp=next) {
950 next = strchr(rp, '.') + 1;
951 if (strncmp(name+3, rp, next-rp) == 0)
952 break;
953 }
954 if (*rp) {
955 if (ldd_mode) {
956 /* Track which names have been resolved
957 * and only report each one once. */
958 static unsigned reported;
959 unsigned mask = 1U<<(rp-reserved);
960 if (!(reported & mask)) {
961 reported |= mask;
962 dprintf(1, "\t%s => %s (%p)\n",
963 name, ldso.name,
964 ldso.base);
965 }
966 }
967 is_self = 1;
968 }
969 }
970 if (!strcmp(name, ldso.name)) is_self = 1;
971 if (is_self) {
972 if (!ldso.prev) {
973 tail->next = &ldso;
974 ldso.prev = tail;
975 tail = &ldso;
976 }
977 return &ldso;
978 }
979 if (strchr(name, '/')) {
980 pathname = name;
981 fd = open(name, O_RDONLY|O_CLOEXEC);
982 } else {
983 /* Search for the name to see if it's already loaded */
984 for (p=head->next; p; p=p->next) {
985 if (p->shortname && !strcmp(p->shortname, name)) {
986 return p;
987 }
988 }
989 if (strlen(name) > NAME_MAX) return 0;
990 fd = -1;
991 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
992 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
993 if (fixup_rpath(p, buf, sizeof buf) < 0)
994 fd = -2; /* Inhibit further search. */
995 if (p->rpath)
996 fd = path_open(name, p->rpath, buf, sizeof buf);
997 }
998 if (fd == -1) {
999 if (!sys_path) {
1000 char *prefix = 0;
1001 size_t prefix_len;
1002 if (ldso.name[0]=='/') {
1003 char *s, *t, *z;
1004 for (s=t=z=ldso.name; *s; s++)
1005 if (*s=='/') z=t, t=s;
1006 prefix_len = z-ldso.name;
1007 if (prefix_len < PATH_MAX)
1008 prefix = ldso.name;
1009 }
1010 if (!prefix) {
1011 prefix = "";
1012 prefix_len = 0;
1013 }
1014 char etc_ldso_path[prefix_len + 1
1015 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1016 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1017 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1018 (int)prefix_len, prefix);
1019 FILE *f = fopen(etc_ldso_path, "rbe");
1020 if (f) {
1021 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
1022 free(sys_path);
1023 sys_path = "";
1024 }
1025 fclose(f);
1026 } else if (errno != ENOENT) {
1027 sys_path = "";
1028 }
1029 }
1030 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1031 fd = path_open(name, sys_path, buf, sizeof buf);
1032 }
1033 pathname = buf;
1034 }
1035 if (fd < 0) return 0;
1036 if (fstat(fd, &st) < 0) {
1037 close(fd);
1038 return 0;
1039 }
1040 for (p=head->next; p; p=p->next) {
1041 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1042 /* If this library was previously loaded with a
1043 * pathname but a search found the same inode,
1044 * setup its shortname so it can be found by name. */
1045 if (!p->shortname && pathname != name)
1046 p->shortname = strrchr(p->name, '/')+1;
1047 close(fd);
1048 return p;
1049 }
1050 }
1051 map = noload ? 0 : map_library(fd, &temp_dso);
1052 close(fd);
1053 if (!map) return 0;
1054
1055 /* Avoid the danger of getting two versions of libc mapped into the
1056 * same process when an absolute pathname was used. The symbols
1057 * checked are chosen to catch both musl and glibc, and to avoid
1058 * false positives from interposition-hack libraries. */
1059 decode_dyn(&temp_dso);
1060 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1061 find_sym(&temp_dso, "stdin", 1).sym) {
1062 unmap_library(&temp_dso);
1063 return load_library("libc.so", needed_by);
1064 }
1065 /* Past this point, if we haven't reached runtime yet, ldso has
1066 * committed either to use the mapped library or to abort execution.
1067 * Unmapping is not possible, so we can safely reclaim gaps. */
1068 if (!runtime) reclaim_gaps(&temp_dso);
1069
1070 /* Allocate storage for the new DSO. When there is TLS, this
1071 * storage must include a reservation for all pre-existing
1072 * threads to obtain copies of both the new TLS, and an
1073 * extended DTV capable of storing an additional slot for
1074 * the newly-loaded DSO. */
1075 alloc_size = sizeof *p + strlen(pathname) + 1;
1076 if (runtime && temp_dso.tls.image) {
1077 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1078 + sizeof(void *) * (tls_cnt+3);
1079 n_th = libc.threads_minus_1 + 1;
1080 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1081 else alloc_size += n_th * per_th;
1082 }
1083 p = calloc(1, alloc_size);
1084 if (!p) {
1085 unmap_library(&temp_dso);
1086 return 0;
1087 }
1088 memcpy(p, &temp_dso, sizeof temp_dso);
1089 p->dev = st.st_dev;
1090 p->ino = st.st_ino;
1091 p->needed_by = needed_by;
1092 p->name = p->buf;
1093 strcpy(p->name, pathname);
1094 /* Add a shortname only if name arg was not an explicit pathname. */
1095 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1096 if (p->tls.image) {
1097 p->tls_id = ++tls_cnt;
1098 tls_align = MAXP2(tls_align, p->tls.align);
1099 #ifdef TLS_ABOVE_TP
1100 p->tls.offset = tls_offset + ( (tls_align-1) &
1101 -(tls_offset + (uintptr_t)p->tls.image) );
1102 tls_offset += p->tls.size;
1103 #else
1104 tls_offset += p->tls.size + p->tls.align - 1;
1105 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1106 & (p->tls.align-1);
1107 p->tls.offset = tls_offset;
1108 #endif
1109 p->new_dtv = (void *)(-sizeof(size_t) &
1110 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1111 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1112 if (tls_tail) tls_tail->next = &p->tls;
1113 else libc.tls_head = &p->tls;
1114 tls_tail = &p->tls;
1115 }
1116
1117 tail->next = p;
1118 p->prev = tail;
1119 tail = p;
1120
1121 if (DL_FDPIC) makefuncdescs(p);
1122
1123 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1124
1125 return p;
1126 }
1127
1128 static void load_deps(struct dso *p)
1129 {
1130 size_t i, ndeps=0;
1131 struct dso ***deps = &p->deps, **tmp, *dep;
1132 for (; p; p=p->next) {
1133 for (i=0; p->dynv[i]; i+=2) {
1134 if (p->dynv[i] != DT_NEEDED) continue;
1135 dep = load_library(p->strings + p->dynv[i+1], p);
1136 if (!dep) {
1137 error("Error loading shared library %s: %m (needed by %s)",
1138 p->strings + p->dynv[i+1], p->name);
1139 if (runtime) longjmp(*rtld_fail, 1);
1140 continue;
1141 }
1142 if (runtime) {
1143 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
1144 if (!tmp) longjmp(*rtld_fail, 1);
1145 tmp[ndeps++] = dep;
1146 tmp[ndeps] = 0;
1147 *deps = tmp;
1148 }
1149 }
1150 }
1151 if (!*deps) *deps = (struct dso **)&nodeps_dummy;
1152 }
1153
1154 static void load_preload(char *s)
1155 {
1156 int tmp;
1157 char *z;
1158 for (z=s; *z; s=z) {
1159 for ( ; *s && (isspace(*s) || *s==':'); s++);
1160 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1161 tmp = *z;
1162 *z = 0;
1163 load_library(s, 0);
1164 *z = tmp;
1165 }
1166 }
1167
1168 static void add_syms(struct dso *p)
1169 {
1170 if (!p->syms_next && syms_tail != p) {
1171 syms_tail->syms_next = p;
1172 syms_tail = p;
1173 }
1174 }
1175
1176 static void revert_syms(struct dso *old_tail)
1177 {
1178 struct dso *p, *next;
1179 /* Chop off the tail of the list of dsos that participate in
1180 * the global symbol table, reverting them to RTLD_LOCAL. */
1181 for (p=old_tail; p; p=next) {
1182 next = p->syms_next;
1183 p->syms_next = 0;
1184 }
1185 syms_tail = old_tail;
1186 }
1187
1188 static void do_mips_relocs(struct dso *p, size_t *got)
1189 {
1190 size_t i, j, rel[2];
1191 unsigned char *base = p->base;
1192 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1193 if (p==&ldso) {
1194 got += i;
1195 } else {
1196 while (i--) *got++ += (size_t)base;
1197 }
1198 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1199 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1200 Sym *sym = p->syms + j;
1201 rel[0] = (unsigned char *)got - base;
1202 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1203 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1204 do_relocs(p, rel, sizeof rel, 2);
1205 }
1206 }
1207
1208 static void reloc_all(struct dso *p)
1209 {
1210 size_t dyn[DYN_CNT];
1211 for (; p; p=p->next) {
1212 if (p->relocated) continue;
1213 decode_vec(p->dynv, dyn, DYN_CNT);
1214 if (NEED_MIPS_GOT_RELOCS)
1215 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1216 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1217 2+(dyn[DT_PLTREL]==DT_RELA));
1218 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1219 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1220
1221 if (head != &ldso && p->relro_start != p->relro_end &&
1222 mprotect(laddr(p, p->relro_start), p->relro_end-p->relro_start, PROT_READ)
1223 && errno != ENOSYS) {
1224 error("Error relocating %s: RELRO protection failed: %m",
1225 p->name);
1226 if (runtime) longjmp(*rtld_fail, 1);
1227 }
1228
1229 p->relocated = 1;
1230 }
1231 }
1232
1233 static void kernel_mapped_dso(struct dso *p)
1234 {
1235 size_t min_addr = -1, max_addr = 0, cnt;
1236 Phdr *ph = p->phdr;
1237 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1238 if (ph->p_type == PT_DYNAMIC) {
1239 p->dynv = laddr(p, ph->p_vaddr);
1240 } else if (ph->p_type == PT_GNU_RELRO) {
1241 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1242 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1243 }
1244 if (ph->p_type != PT_LOAD) continue;
1245 if (ph->p_vaddr < min_addr)
1246 min_addr = ph->p_vaddr;
1247 if (ph->p_vaddr+ph->p_memsz > max_addr)
1248 max_addr = ph->p_vaddr+ph->p_memsz;
1249 }
1250 min_addr &= -PAGE_SIZE;
1251 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1252 p->map = p->base + min_addr;
1253 p->map_len = max_addr - min_addr;
1254 p->kernel_mapped = 1;
1255 }
1256
1257 void __libc_exit_fini()
1258 {
1259 struct dso *p;
1260 size_t dyn[DYN_CNT];
1261 for (p=fini_head; p; p=p->fini_next) {
1262 if (!p->constructed) continue;
1263 decode_vec(p->dynv, dyn, DYN_CNT);
1264 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1265 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1266 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1267 while (n--) ((void (*)(void))*--fn)();
1268 }
1269 #ifndef NO_LEGACY_INITFINI
1270 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1271 fpaddr(p, dyn[DT_FINI])();
1272 #endif
1273 }
1274 }
1275
1276 static void do_init_fini(struct dso *p)
1277 {
1278 size_t dyn[DYN_CNT];
1279 int need_locking = libc.threads_minus_1;
1280 /* Allow recursive calls that arise when a library calls
1281 * dlopen from one of its constructors, but block any
1282 * other threads until all ctors have finished. */
1283 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1284 for (; p; p=p->prev) {
1285 if (p->constructed) continue;
1286 p->constructed = 1;
1287 decode_vec(p->dynv, dyn, DYN_CNT);
1288 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1289 p->fini_next = fini_head;
1290 fini_head = p;
1291 }
1292 #ifndef NO_LEGACY_INITFINI
1293 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1294 fpaddr(p, dyn[DT_INIT])();
1295 #endif
1296 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1297 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1298 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1299 while (n--) ((void (*)(void))*fn++)();
1300 }
1301 if (!need_locking && libc.threads_minus_1) {
1302 need_locking = 1;
1303 pthread_mutex_lock(&init_fini_lock);
1304 }
1305 }
1306 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1307 }
1308
1309 void __libc_start_init(void)
1310 {
1311 do_init_fini(tail);
1312 }
1313
1314 static void dl_debug_state(void)
1315 {
1316 }
1317
1318 weak_alias(dl_debug_state, _dl_debug_state);
1319
1320 void __init_tls(size_t *auxv)
1321 {
1322 }
1323
1324 hidden void *__tls_get_new(tls_mod_off_t *v)
1325 {
1326 pthread_t self = __pthread_self();
1327
1328 /* Block signals to make accessing new TLS async-signal-safe */
1329 sigset_t set;
1330 __block_all_sigs(&set);
1331 if (v[0]<=(size_t)self->dtv[0]) {
1332 __restore_sigs(&set);
1333 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1334 }
1335
1336 /* This is safe without any locks held because, if the caller
1337 * is able to request the Nth entry of the DTV, the DSO list
1338 * must be valid at least that far out and it was synchronized
1339 * at program startup or by an already-completed call to dlopen. */
1340 struct dso *p;
1341 for (p=head; p->tls_id != v[0]; p=p->next);
1342
1343 /* Get new DTV space from new DSO if needed */
1344 if (v[0] > (size_t)self->dtv[0]) {
1345 void **newdtv = p->new_dtv +
1346 (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
1347 memcpy(newdtv, self->dtv,
1348 ((size_t)self->dtv[0]+1) * sizeof(void *));
1349 newdtv[0] = (void *)v[0];
1350 self->dtv = self->dtv_copy = newdtv;
1351 }
1352
1353 /* Get new TLS memory from all new DSOs up to the requested one */
1354 unsigned char *mem;
1355 for (p=head; ; p=p->next) {
1356 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1357 mem = p->new_tls + (p->tls.size + p->tls.align)
1358 * a_fetch_add(&p->new_tls_idx,1);
1359 mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1360 & (p->tls.align-1);
1361 self->dtv[p->tls_id] = mem;
1362 memcpy(mem, p->tls.image, p->tls.len);
1363 if (p->tls_id == v[0]) break;
1364 }
1365 __restore_sigs(&set);
1366 return mem + v[1] + DTP_OFFSET;
1367 }
1368
1369 static void update_tls_size()
1370 {
1371 libc.tls_cnt = tls_cnt;
1372 libc.tls_align = tls_align;
1373 libc.tls_size = ALIGN(
1374 (1+tls_cnt) * sizeof(void *) +
1375 tls_offset +
1376 sizeof(struct pthread) +
1377 tls_align * 2,
1378 tls_align);
1379 }
1380
1381 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1382 * following stage 2 and stage 3 functions via primitive symbolic lookup
1383 * since it does not have access to their addresses to begin with. */
1384
1385 /* Stage 2 of the dynamic linker is called after relative relocations
1386 * have been processed. It can make function calls to static functions
1387 * and access string literals and static data, but cannot use extern
1388 * symbols. Its job is to perform symbolic relocations on the dynamic
1389 * linker itself, but some of the relocations performed may need to be
1390 * replaced later due to copy relocations in the main program. */
1391
1392 hidden void __dls2(unsigned char *base, size_t *sp)
1393 {
1394 if (DL_FDPIC) {
1395 void *p1 = (void *)sp[-2];
1396 void *p2 = (void *)sp[-1];
1397 if (!p1) {
1398 size_t *auxv, aux[AUX_CNT];
1399 for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
1400 decode_vec(auxv, aux, AUX_CNT);
1401 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1402 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1403 }
1404 app_loadmap = p2 ? p1 : 0;
1405 ldso.loadmap = p2 ? p2 : p1;
1406 ldso.base = laddr(&ldso, 0);
1407 } else {
1408 ldso.base = base;
1409 }
1410 Ehdr *ehdr = (void *)ldso.base;
1411 ldso.name = ldso.shortname = "libc.so";
1412 ldso.phnum = ehdr->e_phnum;
1413 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1414 ldso.phentsize = ehdr->e_phentsize;
1415 kernel_mapped_dso(&ldso);
1416 decode_dyn(&ldso);
1417
1418 if (DL_FDPIC) makefuncdescs(&ldso);
1419
1420 /* Prepare storage for to save clobbered REL addends so they
1421 * can be reused in stage 3. There should be very few. If
1422 * something goes wrong and there are a huge number, abort
1423 * instead of risking stack overflow. */
1424 size_t dyn[DYN_CNT];
1425 decode_vec(ldso.dynv, dyn, DYN_CNT);
1426 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1427 size_t rel_size = dyn[DT_RELSZ];
1428 size_t symbolic_rel_cnt = 0;
1429 apply_addends_to = rel;
1430 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1431 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1432 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1433 size_t addends[symbolic_rel_cnt+1];
1434 saved_addends = addends;
1435
1436 head = &ldso;
1437 reloc_all(&ldso);
1438
1439 ldso.relocated = 0;
1440
1441 /* Call dynamic linker stage-3, __dls3, looking it up
1442 * symbolically as a barrier against moving the address
1443 * load across the above relocation processing. */
1444 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1445 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
1446 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
1447 }
1448
1449 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1450 * fully functional. Its job is to load (if not already loaded) and
1451 * process dependencies and relocations for the main application and
1452 * transfer control to its entry point. */
1453
1454 _Noreturn void __dls3(size_t *sp)
1455 {
1456 static struct dso app, vdso;
1457 size_t aux[AUX_CNT], *auxv;
1458 size_t i;
1459 char *env_preload=0;
1460 char *replace_argv0=0;
1461 size_t vdso_base;
1462 int argc = *sp;
1463 char **argv = (void *)(sp+1);
1464 char **argv_orig = argv;
1465 char **envp = argv+argc+1;
1466
1467 /* Find aux vector just past environ[] and use it to initialize
1468 * global data that may be needed before we can make syscalls. */
1469 __environ = envp;
1470 for (i=argc+1; argv[i]; i++);
1471 libc.auxv = auxv = (void *)(argv+i+1);
1472 decode_vec(auxv, aux, AUX_CNT);
1473 __hwcap = aux[AT_HWCAP];
1474 libc.page_size = aux[AT_PAGESZ];
1475 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1476 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1477
1478 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1479 * use during dynamic linking. If possible it will also serve as the
1480 * thread pointer at runtime. */
1481 libc.tls_size = sizeof builtin_tls;
1482 libc.tls_align = tls_align;
1483 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1484 a_crash();
1485 }
1486
1487 /* Only trust user/env if kernel says we're not suid/sgid */
1488 if (!libc.secure) {
1489 env_path = getenv("LD_LIBRARY_PATH");
1490 env_preload = getenv("LD_PRELOAD");
1491 }
1492
1493 /* If the main program was already loaded by the kernel,
1494 * AT_PHDR will point to some location other than the dynamic
1495 * linker's program headers. */
1496 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1497 size_t interp_off = 0;
1498 size_t tls_image = 0;
1499 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1500 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1501 app.phnum = aux[AT_PHNUM];
1502 app.phentsize = aux[AT_PHENT];
1503 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1504 if (phdr->p_type == PT_PHDR)
1505 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1506 else if (phdr->p_type == PT_INTERP)
1507 interp_off = (size_t)phdr->p_vaddr;
1508 else if (phdr->p_type == PT_TLS) {
1509 tls_image = phdr->p_vaddr;
1510 app.tls.len = phdr->p_filesz;
1511 app.tls.size = phdr->p_memsz;
1512 app.tls.align = phdr->p_align;
1513 }
1514 }
1515 if (DL_FDPIC) app.loadmap = app_loadmap;
1516 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1517 if (interp_off) ldso.name = laddr(&app, interp_off);
1518 if ((aux[0] & (1UL<<AT_EXECFN))
1519 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1520 app.name = (char *)aux[AT_EXECFN];
1521 else
1522 app.name = argv[0];
1523 kernel_mapped_dso(&app);
1524 } else {
1525 int fd;
1526 char *ldname = argv[0];
1527 size_t l = strlen(ldname);
1528 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1529 argv++;
1530 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1531 char *opt = argv[0]+2;
1532 *argv++ = (void *)-1;
1533 if (!*opt) {
1534 break;
1535 } else if (!memcmp(opt, "list", 5)) {
1536 ldd_mode = 1;
1537 } else if (!memcmp(opt, "library-path", 12)) {
1538 if (opt[12]=='=') env_path = opt+13;
1539 else if (opt[12]) *argv = 0;
1540 else if (*argv) env_path = *argv++;
1541 } else if (!memcmp(opt, "preload", 7)) {
1542 if (opt[7]=='=') env_preload = opt+8;
1543 else if (opt[7]) *argv = 0;
1544 else if (*argv) env_preload = *argv++;
1545 } else if (!memcmp(opt, "argv0", 5)) {
1546 if (opt[5]=='=') replace_argv0 = opt+6;
1547 else if (opt[5]) *argv = 0;
1548 else if (*argv) replace_argv0 = *argv++;
1549 } else {
1550 argv[0] = 0;
1551 }
1552 }
1553 argv[-1] = (void *)(argc - (argv-argv_orig));
1554 if (!argv[0]) {
1555 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1556 "Version %s\n"
1557 "Dynamic Program Loader\n"
1558 "Usage: %s [options] [--] pathname%s\n",
1559 __libc_version, ldname,
1560 ldd_mode ? "" : " [args]");
1561 _exit(1);
1562 }
1563 fd = open(argv[0], O_RDONLY);
1564 if (fd < 0) {
1565 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1566 _exit(1);
1567 }
1568 Ehdr *ehdr = (void *)map_library(fd, &app);
1569 if (!ehdr) {
1570 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1571 _exit(1);
1572 }
1573 close(fd);
1574 ldso.name = ldname;
1575 app.name = argv[0];
1576 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1577 /* Find the name that would have been used for the dynamic
1578 * linker had ldd not taken its place. */
1579 if (ldd_mode) {
1580 for (i=0; i<app.phnum; i++) {
1581 if (app.phdr[i].p_type == PT_INTERP)
1582 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1583 }
1584 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1585 }
1586 }
1587 if (app.tls.size) {
1588 libc.tls_head = tls_tail = &app.tls;
1589 app.tls_id = tls_cnt = 1;
1590 #ifdef TLS_ABOVE_TP
1591 app.tls.offset = GAP_ABOVE_TP;
1592 app.tls.offset += -GAP_ABOVE_TP & (app.tls.align-1);
1593 tls_offset = app.tls.offset + app.tls.size
1594 + ( -((uintptr_t)app.tls.image + app.tls.size)
1595 & (app.tls.align-1) );
1596 #else
1597 tls_offset = app.tls.offset = app.tls.size
1598 + ( -((uintptr_t)app.tls.image + app.tls.size)
1599 & (app.tls.align-1) );
1600 #endif
1601 tls_align = MAXP2(tls_align, app.tls.align);
1602 }
1603 decode_dyn(&app);
1604 if (DL_FDPIC) {
1605 makefuncdescs(&app);
1606 if (!app.loadmap) {
1607 app.loadmap = (void *)&app_dummy_loadmap;
1608 app.loadmap->nsegs = 1;
1609 app.loadmap->segs[0].addr = (size_t)app.map;
1610 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1611 - (size_t)app.base;
1612 app.loadmap->segs[0].p_memsz = app.map_len;
1613 }
1614 argv[-3] = (void *)app.loadmap;
1615 }
1616
1617 /* Initial dso chain consists only of the app. */
1618 head = tail = syms_tail = &app;
1619
1620 /* Donate unused parts of app and library mapping to malloc */
1621 reclaim_gaps(&app);
1622 reclaim_gaps(&ldso);
1623
1624 /* Load preload/needed libraries, add symbols to global namespace. */
1625 if (env_preload) load_preload(env_preload);
1626 load_deps(&app);
1627 for (struct dso *p=head; p; p=p->next)
1628 add_syms(p);
1629
1630 /* Attach to vdso, if provided by the kernel, last so that it does
1631 * not become part of the global namespace. */
1632 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1633 Ehdr *ehdr = (void *)vdso_base;
1634 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1635 vdso.phnum = ehdr->e_phnum;
1636 vdso.phentsize = ehdr->e_phentsize;
1637 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1638 if (phdr->p_type == PT_DYNAMIC)
1639 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1640 if (phdr->p_type == PT_LOAD)
1641 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1642 }
1643 vdso.name = "";
1644 vdso.shortname = "linux-gate.so.1";
1645 vdso.relocated = 1;
1646 decode_dyn(&vdso);
1647 vdso.prev = tail;
1648 tail->next = &vdso;
1649 tail = &vdso;
1650 }
1651
1652 for (i=0; app.dynv[i]; i+=2) {
1653 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1654 app.dynv[i+1] = (size_t)&debug;
1655 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
1656 size_t *ptr = (size_t *) app.dynv[i+1];
1657 *ptr = (size_t)&debug;
1658 }
1659 }
1660
1661 /* The main program must be relocated LAST since it may contin
1662 * copy relocations which depend on libraries' relocations. */
1663 reloc_all(app.next);
1664 reloc_all(&app);
1665
1666 update_tls_size();
1667 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1668 void *initial_tls = calloc(libc.tls_size, 1);
1669 if (!initial_tls) {
1670 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1671 argv[0], libc.tls_size);
1672 _exit(127);
1673 }
1674 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1675 a_crash();
1676 }
1677 } else {
1678 size_t tmp_tls_size = libc.tls_size;
1679 pthread_t self = __pthread_self();
1680 /* Temporarily set the tls size to the full size of
1681 * builtin_tls so that __copy_tls will use the same layout
1682 * as it did for before. Then check, just to be safe. */
1683 libc.tls_size = sizeof builtin_tls;
1684 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1685 libc.tls_size = tmp_tls_size;
1686 }
1687 static_tls_cnt = tls_cnt;
1688
1689 if (ldso_fail) _exit(127);
1690 if (ldd_mode) _exit(0);
1691
1692 /* Determine if malloc was interposed by a replacement implementation
1693 * so that calloc and the memalign family can harden against the
1694 * possibility of incomplete replacement. */
1695 if (find_sym(head, "malloc", 1).dso != &ldso)
1696 __malloc_replaced = 1;
1697
1698 /* Switch to runtime mode: any further failures in the dynamic
1699 * linker are a reportable failure rather than a fatal startup
1700 * error. */
1701 runtime = 1;
1702
1703 debug.ver = 1;
1704 debug.bp = dl_debug_state;
1705 debug.head = head;
1706 debug.base = ldso.base;
1707 debug.state = 0;
1708 _dl_debug_state();
1709
1710 if (replace_argv0) argv[0] = replace_argv0;
1711
1712 errno = 0;
1713
1714 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1715 for(;;);
1716 }
1717
1718 static void prepare_lazy(struct dso *p)
1719 {
1720 size_t dyn[DYN_CNT], n, flags1=0;
1721 decode_vec(p->dynv, dyn, DYN_CNT);
1722 search_vec(p->dynv, &flags1, DT_FLAGS_1);
1723 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
1724 return;
1725 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
1726 if (NEED_MIPS_GOT_RELOCS) {
1727 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1728 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1729 n += i-j;
1730 }
1731 p->lazy = calloc(n, 3*sizeof(size_t));
1732 if (!p->lazy) {
1733 error("Error preparing lazy relocation for %s: %m", p->name);
1734 longjmp(*rtld_fail, 1);
1735 }
1736 p->lazy_next = lazy_head;
1737 lazy_head = p;
1738 }
1739
1740 void *dlopen(const char *file, int mode)
1741 {
1742 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
1743 struct tls_module *orig_tls_tail;
1744 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1745 size_t i;
1746 int cs;
1747 jmp_buf jb;
1748
1749 if (!file) return head;
1750
1751 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1752 pthread_rwlock_wrlock(&lock);
1753 __inhibit_ptc();
1754
1755 p = 0;
1756 orig_tls_tail = tls_tail;
1757 orig_tls_cnt = tls_cnt;
1758 orig_tls_offset = tls_offset;
1759 orig_tls_align = tls_align;
1760 orig_lazy_head = lazy_head;
1761 orig_syms_tail = syms_tail;
1762 orig_tail = tail;
1763 noload = mode & RTLD_NOLOAD;
1764
1765 rtld_fail = &jb;
1766 if (setjmp(*rtld_fail)) {
1767 /* Clean up anything new that was (partially) loaded */
1768 revert_syms(orig_syms_tail);
1769 for (p=orig_tail->next; p; p=next) {
1770 next = p->next;
1771 while (p->td_index) {
1772 void *tmp = p->td_index->next;
1773 free(p->td_index);
1774 p->td_index = tmp;
1775 }
1776 free(p->funcdescs);
1777 if (p->rpath != p->rpath_orig)
1778 free(p->rpath);
1779 if (p->deps != &nodeps_dummy)
1780 free(p->deps);
1781 unmap_library(p);
1782 free(p);
1783 }
1784 if (!orig_tls_tail) libc.tls_head = 0;
1785 tls_tail = orig_tls_tail;
1786 if (tls_tail) tls_tail->next = 0;
1787 tls_cnt = orig_tls_cnt;
1788 tls_offset = orig_tls_offset;
1789 tls_align = orig_tls_align;
1790 lazy_head = orig_lazy_head;
1791 tail = orig_tail;
1792 tail->next = 0;
1793 p = 0;
1794 goto end;
1795 } else p = load_library(file, head);
1796
1797 if (!p) {
1798 error(noload ?
1799 "Library %s is not already loaded" :
1800 "Error loading shared library %s: %m",
1801 file);
1802 goto end;
1803 }
1804
1805 /* First load handling */
1806 int first_load = !p->deps;
1807 if (first_load) {
1808 load_deps(p);
1809 if (!p->relocated && (mode & RTLD_LAZY)) {
1810 prepare_lazy(p);
1811 for (i=0; p->deps[i]; i++)
1812 if (!p->deps[i]->relocated)
1813 prepare_lazy(p->deps[i]);
1814 }
1815 }
1816 if (first_load || (mode & RTLD_GLOBAL)) {
1817 /* Make new symbols global, at least temporarily, so we can do
1818 * relocations. If not RTLD_GLOBAL, this is reverted below. */
1819 add_syms(p);
1820 for (i=0; p->deps[i]; i++)
1821 add_syms(p->deps[i]);
1822 }
1823 if (first_load) {
1824 reloc_all(p);
1825 }
1826
1827 /* If RTLD_GLOBAL was not specified, undo any new additions
1828 * to the global symbol table. This is a nop if the library was
1829 * previously loaded and already global. */
1830 if (!(mode & RTLD_GLOBAL))
1831 revert_syms(orig_syms_tail);
1832
1833 /* Processing of deferred lazy relocations must not happen until
1834 * the new libraries are committed; otherwise we could end up with
1835 * relocations resolved to symbol definitions that get removed. */
1836 redo_lazy_relocs();
1837
1838 update_tls_size();
1839 _dl_debug_state();
1840 orig_tail = tail;
1841 end:
1842 __release_ptc();
1843 if (p) gencnt++;
1844 pthread_rwlock_unlock(&lock);
1845 if (p) do_init_fini(orig_tail);
1846 pthread_setcancelstate(cs, 0);
1847 return p;
1848 }
1849
1850 hidden int __dl_invalid_handle(void *h)
1851 {
1852 struct dso *p;
1853 for (p=head; p; p=p->next) if (h==p) return 0;
1854 error("Invalid library handle %p", (void *)h);
1855 return 1;
1856 }
1857
1858 static void *addr2dso(size_t a)
1859 {
1860 struct dso *p;
1861 size_t i;
1862 if (DL_FDPIC) for (p=head; p; p=p->next) {
1863 i = count_syms(p);
1864 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
1865 return p;
1866 }
1867 for (p=head; p; p=p->next) {
1868 if (DL_FDPIC && p->loadmap) {
1869 for (i=0; i<p->loadmap->nsegs; i++) {
1870 if (a-p->loadmap->segs[i].p_vaddr
1871 < p->loadmap->segs[i].p_memsz)
1872 return p;
1873 }
1874 } else {
1875 Phdr *ph = p->phdr;
1876 size_t phcnt = p->phnum;
1877 size_t entsz = p->phentsize;
1878 size_t base = (size_t)p->base;
1879 for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
1880 if (ph->p_type != PT_LOAD) continue;
1881 if (a-base-ph->p_vaddr < ph->p_memsz)
1882 return p;
1883 }
1884 if (a-(size_t)p->map < p->map_len)
1885 return 0;
1886 }
1887 }
1888 return 0;
1889 }
1890
1891 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1892 {
1893 size_t i;
1894 uint32_t h = 0, gh = 0, *ght;
1895 Sym *sym;
1896 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1897 if (p == RTLD_DEFAULT) {
1898 p = head;
1899 } else if (p == RTLD_NEXT) {
1900 p = addr2dso((size_t)ra);
1901 if (!p) p=head;
1902 p = p->next;
1903 }
1904 struct symdef def = find_sym(p, s, 0);
1905 if (!def.sym) goto failed;
1906 if ((def.sym->st_info&0xf) == STT_TLS)
1907 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value});
1908 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
1909 return def.dso->funcdescs + (def.sym - def.dso->syms);
1910 return laddr(def.dso, def.sym->st_value);
1911 }
1912 if (__dl_invalid_handle(p))
1913 return 0;
1914 if ((ght = p->ghashtab)) {
1915 gh = gnu_hash(s);
1916 sym = gnu_lookup(gh, ght, p, s);
1917 } else {
1918 h = sysv_hash(s);
1919 sym = sysv_lookup(s, h, p);
1920 }
1921 if (sym && (sym->st_info&0xf) == STT_TLS)
1922 return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value});
1923 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1924 return p->funcdescs + (sym - p->syms);
1925 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1926 return laddr(p, sym->st_value);
1927 for (i=0; p->deps[i]; i++) {
1928 if ((ght = p->deps[i]->ghashtab)) {
1929 if (!gh) gh = gnu_hash(s);
1930 sym = gnu_lookup(gh, ght, p->deps[i], s);
1931 } else {
1932 if (!h) h = sysv_hash(s);
1933 sym = sysv_lookup(s, h, p->deps[i]);
1934 }
1935 if (sym && (sym->st_info&0xf) == STT_TLS)
1936 return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value});
1937 if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
1938 return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
1939 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1940 return laddr(p->deps[i], sym->st_value);
1941 }
1942 failed:
1943 error("Symbol not found: %s", s);
1944 return 0;
1945 }
1946
1947 int dladdr(const void *addr_arg, Dl_info *info)
1948 {
1949 size_t addr = (size_t)addr_arg;
1950 struct dso *p;
1951 Sym *sym, *bestsym;
1952 uint32_t nsym;
1953 char *strings;
1954 size_t best = 0;
1955 size_t besterr = -1;
1956
1957 pthread_rwlock_rdlock(&lock);
1958 p = addr2dso(addr);
1959 pthread_rwlock_unlock(&lock);
1960
1961 if (!p) return 0;
1962
1963 sym = p->syms;
1964 strings = p->strings;
1965 nsym = count_syms(p);
1966
1967 if (DL_FDPIC) {
1968 size_t idx = (addr-(size_t)p->funcdescs)
1969 / sizeof(*p->funcdescs);
1970 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
1971 best = (size_t)(p->funcdescs + idx);
1972 bestsym = sym + idx;
1973 besterr = 0;
1974 }
1975 }
1976
1977 if (!best) for (; nsym; nsym--, sym++) {
1978 if (sym->st_value
1979 && (1<<(sym->st_info&0xf) & OK_TYPES)
1980 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1981 size_t symaddr = (size_t)laddr(p, sym->st_value);
1982 if (symaddr > addr || symaddr <= best)
1983 continue;
1984 best = symaddr;
1985 bestsym = sym;
1986 besterr = addr - symaddr;
1987 if (addr == symaddr)
1988 break;
1989 }
1990 }
1991
1992 if (bestsym && besterr > bestsym->st_size-1) {
1993 best = 0;
1994 bestsym = 0;
1995 }
1996
1997 info->dli_fname = p->name;
1998 info->dli_fbase = p->map;
1999
2000 if (!best) {
2001 info->dli_sname = 0;
2002 info->dli_saddr = 0;
2003 return 1;
2004 }
2005
2006 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2007 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2008 info->dli_sname = strings + bestsym->st_name;
2009 info->dli_saddr = (void *)best;
2010
2011 return 1;
2012 }
2013
2014 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2015 {
2016 void *res;
2017 pthread_rwlock_rdlock(&lock);
2018 res = do_dlsym(p, s, ra);
2019 pthread_rwlock_unlock(&lock);
2020 return res;
2021 }
2022
2023 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2024 {
2025 struct dso *current;
2026 struct dl_phdr_info info;
2027 int ret = 0;
2028 for(current = head; current;) {
2029 info.dlpi_addr = (uintptr_t)current->base;
2030 info.dlpi_name = current->name;
2031 info.dlpi_phdr = current->phdr;
2032 info.dlpi_phnum = current->phnum;
2033 info.dlpi_adds = gencnt;
2034 info.dlpi_subs = 0;
2035 info.dlpi_tls_modid = current->tls_id;
2036 info.dlpi_tls_data = current->tls.image;
2037
2038 ret = (callback)(&info, sizeof (info), data);
2039
2040 if (ret != 0) break;
2041
2042 pthread_rwlock_rdlock(&lock);
2043 current = current->next;
2044 pthread_rwlock_unlock(&lock);
2045 }
2046 return ret;
2047 }
2048
2049 static void error(const char *fmt, ...)
2050 {
2051 va_list ap;
2052 va_start(ap, fmt);
2053 if (!runtime) {
2054 vdprintf(2, fmt, ap);
2055 dprintf(2, "\n");
2056 ldso_fail = 1;
2057 va_end(ap);
2058 return;
2059 }
2060 __dl_vseterr(fmt, ap);
2061 va_end(ap);
2062 }
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