1 #define _GNU_SOURCE
2 #define SYSCALL_NO_TLS 1
3 #include <stdlib.h>
4 #include <stdarg.h>
5 #include <stddef.h>
6 #include <string.h>
7 #include <unistd.h>
8 #include <stdint.h>
9 #include <elf.h>
10 #include <sys/mman.h>
11 #include <limits.h>
12 #include <fcntl.h>
13 #include <sys/stat.h>
14 #include <errno.h>
15 #include <link.h>
16 #include <setjmp.h>
17 #include <pthread.h>
18 #include <ctype.h>
19 #include <dlfcn.h>
20 #include <semaphore.h>
21 #include <sys/membarrier.h>
22 #include "pthread_impl.h"
23 #include "fork_impl.h"
24 #include "libc.h"
25 #include "dynlink.h"
26
27 #define STRINGIFY(x) __STRINGIFY(x)
28 #define __STRINGIFY(x) #x
29
30 #define malloc __libc_malloc
31 #define calloc __libc_calloc
32 #define realloc __libc_realloc
33 #define free __libc_free
34
35 static void error_impl(const char *, ...);
36 static void error_noop(const char *, ...);
37 static void (*error)(const char *, ...) = error_noop;
38
39 #define MAXP2(a,b) (-(-(a)&-(b)))
40 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
41
42 #define container_of(p,t,m) ((t*)((char *)(p)-offsetof(t,m)))
43 #define countof(a) ((sizeof (a))/(sizeof (a)[0]))
44
45 struct debug {
46 int ver;
47 void *head;
48 void (*bp)(void);
49 int state;
50 void *base;
51 };
52
53 struct td_index {
54 size_t args[2];
55 struct td_index *next;
56 };
57
58 struct dso {
59 #if DL_FDPIC
60 struct fdpic_loadmap *loadmap;
61 #else
62 unsigned char *base;
63 #endif
64 char *name;
65 size_t *dynv;
66 struct dso *next, *prev;
67
68 int elfmachine;
69 int elfclass;
70 Phdr *phdr;
71 int phnum;
72 size_t phentsize;
73 Sym *syms;
74 Elf_Symndx *hashtab;
75 uint32_t *ghashtab;
76 int16_t *versym;
77 char *strings;
78 struct dso *syms_next, *lazy_next;
79 size_t *lazy, lazy_cnt;
80 unsigned char *map;
81 size_t map_len;
82 dev_t dev;
83 ino_t ino;
84 char relocated;
85 char constructed;
86 char kernel_mapped;
87 char mark;
88 char bfs_built;
89 char runtime_loaded;
90 struct dso **deps, *needed_by;
91 size_t ndeps_direct;
92 size_t next_dep;
93 pthread_t ctor_visitor;
94 char *rpath_orig, *rpath;
95 struct tls_module tls;
96 size_t tls_id;
97 size_t relro_start, relro_end;
98 uintptr_t *new_dtv;
99 unsigned char *new_tls;
100 struct td_index *td_index;
101 struct dso *fini_next;
102 char *shortname;
103 #if DL_FDPIC
104 unsigned char *base;
105 #else
106 struct fdpic_loadmap *loadmap;
107 #endif
108 struct funcdesc {
109 void *addr;
110 size_t *got;
111 } *funcdescs;
112 size_t *got;
113 char buf[];
114 };
115
116 struct symdef {
117 Sym *sym;
118 struct dso *dso;
119 };
120
121 typedef void (*stage3_func)(size_t *, size_t *);
122
123 static struct builtin_tls {
124 char c;
125 struct pthread pt;
126 void *space[16];
127 } builtin_tls[1];
128 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
129
130 #define ADDEND_LIMIT 4096
131 static size_t *saved_addends, *apply_addends_to;
132
133 static struct dso ldso;
134 static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
135 static char *env_path, *sys_path;
136 static unsigned long long gencnt;
137 static int runtime;
138 static int ldd_mode;
139 static int ldso_fail;
140 static int noload;
141 static int shutting_down;
142 static jmp_buf *rtld_fail;
143 static pthread_rwlock_t lock;
144 static struct debug debug;
145 static struct tls_module *tls_tail;
146 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
147 static size_t static_tls_cnt;
148 static pthread_mutex_t init_fini_lock;
149 static pthread_cond_t ctor_cond;
150 static struct dso *builtin_deps[2];
151 static struct dso *const no_deps[1];
152 static struct dso *builtin_ctor_queue[4];
153 static struct dso **main_ctor_queue;
154 static struct fdpic_loadmap *app_loadmap;
155 static struct fdpic_dummy_loadmap app_dummy_loadmap;
156
157 struct debug *_dl_debug_addr = &debug;
158 static void (*exe_dl_debug_state)(void) = 0;
159
160 extern hidden int __malloc_replaced;
161
162 hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
163
164 extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
165
166 weak_alias(__init_array_start, __init_array_end);
167 weak_alias(__fini_array_start, __fini_array_end);
168
dl_strcmp(const char * l,const char * r)169 static int dl_strcmp(const char *l, const char *r)
170 {
171 for (; *l==*r && *l; l++, r++);
172 return *(unsigned char *)l - *(unsigned char *)r;
173 }
174 #define strcmp(l,r) dl_strcmp(l,r)
175
176 /* Compute load address for a virtual address in a given dso. */
177 #if DL_FDPIC
laddr(const struct dso * p,size_t v)178 static void *laddr(const struct dso *p, size_t v)
179 {
180 size_t j=0;
181 if (!p->loadmap) return p->base + v;
182 for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
183 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
184 }
laddr_pg(const struct dso * p,size_t v)185 static void *laddr_pg(const struct dso *p, size_t v)
186 {
187 size_t j=0;
188 size_t pgsz = PAGE_SIZE;
189 if (!p->loadmap) return p->base + v;
190 for (j=0; ; j++) {
191 size_t a = p->loadmap->segs[j].p_vaddr;
192 size_t b = a + p->loadmap->segs[j].p_memsz;
193 a &= -pgsz;
194 b += pgsz-1;
195 b &= -pgsz;
196 if (v-a<b-a) break;
197 }
198 return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
199 }
fdbarrier(void * p)200 static void (*fdbarrier(void *p))()
201 {
202 void (*fd)();
203 __asm__("" : "=r"(fd) : "0"(p));
204 return fd;
205 }
206 #define fpaddr(p, v) fdbarrier((&(struct funcdesc){ \
207 laddr(p, v), (p)->got }))
208 #else
209 #define laddr(p, v) (void *)((p)->base + (v))
210 #define laddr_pg(p, v) laddr(p, v)
211 #define fpaddr(p, v) ((void (*)())laddr(p, v))
212 #endif
213
decode_vec(size_t * v,size_t * a,size_t cnt)214 static void decode_vec(size_t *v, size_t *a, size_t cnt)
215 {
216 size_t i;
217 for (i=0; i<cnt; i++) a[i] = 0;
218 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
219 if (v[0] < 8*sizeof(long))
220 a[0] |= 1UL<<v[0];
221 a[v[0]] = v[1];
222 }
223 }
224
search_vec(size_t * v,size_t * r,size_t key)225 static int search_vec(size_t *v, size_t *r, size_t key)
226 {
227 for (; v[0]!=key; v+=2)
228 if (!v[0]) return 0;
229 *r = v[1];
230 return 1;
231 }
232
sysv_hash(const char * s0)233 static uint32_t sysv_hash(const char *s0)
234 {
235 const unsigned char *s = (void *)s0;
236 uint_fast32_t h = 0;
237 while (*s) {
238 h = 16*h + *s++;
239 h ^= h>>24 & 0xf0;
240 }
241 return h & 0xfffffff;
242 }
243
gnu_hash(const char * s0)244 static uint32_t gnu_hash(const char *s0)
245 {
246 const unsigned char *s = (void *)s0;
247 uint_fast32_t h = 5381;
248 for (; *s; s++)
249 h += h*32 + *s;
250 return h;
251 }
252
sysv_lookup(const char * s,uint32_t h,struct dso * dso)253 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
254 {
255 size_t i;
256 Sym *syms = dso->syms;
257 Elf_Symndx *hashtab = dso->hashtab;
258 char *strings = dso->strings;
259 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
260 if ((!dso->versym || dso->versym[i] >= 0)
261 && (!strcmp(s, strings+syms[i].st_name)))
262 return syms+i;
263 }
264 return 0;
265 }
266
gnu_lookup(uint32_t h1,uint32_t * hashtab,struct dso * dso,const char * s)267 static Sym *gnu_lookup(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s)
268 {
269 uint32_t nbuckets = hashtab[0];
270 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
271 uint32_t i = buckets[h1 % nbuckets];
272
273 if (!i) return 0;
274
275 uint32_t *hashval = buckets + nbuckets + (i - hashtab[1]);
276
277 for (h1 |= 1; ; i++) {
278 uint32_t h2 = *hashval++;
279 if ((h1 == (h2|1)) && (!dso->versym || dso->versym[i] >= 0)
280 && !strcmp(s, dso->strings + dso->syms[i].st_name))
281 return dso->syms+i;
282 if (h2 & 1) break;
283 }
284
285 return 0;
286 }
287
gnu_lookup_filtered(uint32_t h1,uint32_t * hashtab,struct dso * dso,const char * s,uint32_t fofs,size_t fmask)288 static Sym *gnu_lookup_filtered(uint32_t h1, uint32_t *hashtab, struct dso *dso, const char *s, uint32_t fofs, size_t fmask)
289 {
290 const size_t *bloomwords = (const void *)(hashtab+4);
291 size_t f = bloomwords[fofs & (hashtab[2]-1)];
292 if (!(f & fmask)) return 0;
293
294 f >>= (h1 >> hashtab[3]) % (8 * sizeof f);
295 if (!(f & 1)) return 0;
296
297 return gnu_lookup(h1, hashtab, dso, s);
298 }
299
300 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
301 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
302
303 #ifndef ARCH_SYM_REJECT_UND
304 #define ARCH_SYM_REJECT_UND(s) 0
305 #endif
306
307 #if defined(__GNUC__)
308 __attribute__((always_inline))
309 #endif
find_sym2(struct dso * dso,const char * s,int need_def,int use_deps)310 static inline struct symdef find_sym2(struct dso *dso, const char *s, int need_def, int use_deps)
311 {
312 uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
313 size_t ghm = 1ul << gh % (8*sizeof(size_t));
314 struct symdef def = {0};
315 struct dso **deps = use_deps ? dso->deps : 0;
316 for (; dso; dso=use_deps ? *deps++ : dso->syms_next) {
317 Sym *sym;
318 if ((ght = dso->ghashtab)) {
319 sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
320 } else {
321 if (!h) h = sysv_hash(s);
322 sym = sysv_lookup(s, h, dso);
323 }
324 if (!sym) continue;
325 if (!sym->st_shndx)
326 if (need_def || (sym->st_info&0xf) == STT_TLS
327 || ARCH_SYM_REJECT_UND(sym))
328 continue;
329 if (!sym->st_value)
330 if ((sym->st_info&0xf) != STT_TLS)
331 continue;
332 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
333 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
334 def.sym = sym;
335 def.dso = dso;
336 break;
337 }
338 return def;
339 }
340
find_sym(struct dso * dso,const char * s,int need_def)341 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
342 {
343 return find_sym2(dso, s, need_def, 0);
344 }
345
do_relocs(struct dso * dso,size_t * rel,size_t rel_size,size_t stride)346 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
347 {
348 unsigned char *base = dso->base;
349 Sym *syms = dso->syms;
350 char *strings = dso->strings;
351 Sym *sym;
352 const char *name;
353 void *ctx;
354 int type;
355 int sym_index;
356 struct symdef def;
357 size_t *reloc_addr;
358 size_t sym_val;
359 size_t tls_val;
360 size_t addend;
361 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
362
363 if (dso == &ldso) {
364 /* Only ldso's REL table needs addend saving/reuse. */
365 if (rel == apply_addends_to)
366 reuse_addends = 1;
367 skip_relative = 1;
368 }
369
370 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
371 if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
372 type = R_TYPE(rel[1]);
373 if (type == REL_NONE) continue;
374 reloc_addr = laddr(dso, rel[0]);
375
376 if (stride > 2) {
377 addend = rel[2];
378 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
379 addend = 0;
380 } else if (reuse_addends) {
381 /* Save original addend in stage 2 where the dso
382 * chain consists of just ldso; otherwise read back
383 * saved addend since the inline one was clobbered. */
384 if (head==&ldso)
385 saved_addends[save_slot] = *reloc_addr;
386 addend = saved_addends[save_slot++];
387 } else {
388 addend = *reloc_addr;
389 }
390
391 sym_index = R_SYM(rel[1]);
392 if (sym_index) {
393 sym = syms + sym_index;
394 name = strings + sym->st_name;
395 ctx = type==REL_COPY ? head->syms_next : head;
396 def = (sym->st_info>>4) == STB_LOCAL
397 ? (struct symdef){ .dso = dso, .sym = sym }
398 : find_sym(ctx, name, type==REL_PLT);
399 if (!def.sym && (sym->st_shndx != SHN_UNDEF
400 || sym->st_info>>4 != STB_WEAK)) {
401 if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
402 dso->lazy[3*dso->lazy_cnt+0] = rel[0];
403 dso->lazy[3*dso->lazy_cnt+1] = rel[1];
404 dso->lazy[3*dso->lazy_cnt+2] = addend;
405 dso->lazy_cnt++;
406 continue;
407 }
408 error("Error relocating %s: %s: symbol not found",
409 dso->name, name);
410 if (runtime) longjmp(*rtld_fail, 1);
411 continue;
412 }
413 } else {
414 sym = 0;
415 def.sym = 0;
416 def.dso = dso;
417 }
418
419 sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
420 tls_val = def.sym ? def.sym->st_value : 0;
421
422 if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
423 && def.dso && def.dso->tls_id > static_tls_cnt) {
424 error("Error relocating %s: %s: initial-exec TLS "
425 "resolves to dynamic definition in %s",
426 dso->name, name, def.dso->name);
427 longjmp(*rtld_fail, 1);
428 }
429
430 switch(type) {
431 case REL_OFFSET:
432 addend -= (size_t)reloc_addr;
433 case REL_SYMBOLIC:
434 case REL_GOT:
435 case REL_PLT:
436 *reloc_addr = sym_val + addend;
437 break;
438 case REL_USYMBOLIC:
439 memcpy(reloc_addr, &(size_t){sym_val + addend}, sizeof(size_t));
440 break;
441 case REL_RELATIVE:
442 *reloc_addr = (size_t)base + addend;
443 break;
444 case REL_SYM_OR_REL:
445 if (sym) *reloc_addr = sym_val + addend;
446 else *reloc_addr = (size_t)base + addend;
447 break;
448 case REL_COPY:
449 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
450 break;
451 case REL_OFFSET32:
452 *(uint32_t *)reloc_addr = sym_val + addend
453 - (size_t)reloc_addr;
454 break;
455 case REL_FUNCDESC:
456 *reloc_addr = def.sym ? (size_t)(def.dso->funcdescs
457 + (def.sym - def.dso->syms)) : 0;
458 break;
459 case REL_FUNCDESC_VAL:
460 if ((sym->st_info&0xf) == STT_SECTION) *reloc_addr += sym_val;
461 else *reloc_addr = sym_val;
462 reloc_addr[1] = def.sym ? (size_t)def.dso->got : 0;
463 break;
464 case REL_DTPMOD:
465 *reloc_addr = def.dso->tls_id;
466 break;
467 case REL_DTPOFF:
468 *reloc_addr = tls_val + addend - DTP_OFFSET;
469 break;
470 #ifdef TLS_ABOVE_TP
471 case REL_TPOFF:
472 *reloc_addr = (def.dso ? tls_val + def.dso->tls.offset + TPOFF_K : 0) + addend;
473 break;
474 #else
475 case REL_TPOFF:
476 *reloc_addr = (def.dso ? tls_val - def.dso->tls.offset : 0) + addend;
477 break;
478 case REL_TPOFF_NEG:
479 *reloc_addr = (def.dso ? def.dso->tls.offset - tls_val : 0) + addend;
480 break;
481 #endif
482 case REL_TLSDESC:
483 if (stride<3) addend = reloc_addr[1];
484 if (def.dso->tls_id > static_tls_cnt) {
485 struct td_index *new = malloc(sizeof *new);
486 if (!new) {
487 error(
488 "Error relocating %s: cannot allocate TLSDESC for %s",
489 dso->name, sym ? name : "(local)" );
490 longjmp(*rtld_fail, 1);
491 }
492 new->next = dso->td_index;
493 dso->td_index = new;
494 new->args[0] = def.dso->tls_id;
495 new->args[1] = tls_val + addend - DTP_OFFSET;
496 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
497 reloc_addr[1] = (size_t)new;
498 } else {
499 reloc_addr[0] = (size_t)__tlsdesc_static;
500 #ifdef TLS_ABOVE_TP
501 reloc_addr[1] = tls_val + def.dso->tls.offset
502 + TPOFF_K + addend;
503 #else
504 reloc_addr[1] = tls_val - def.dso->tls.offset
505 + addend;
506 #endif
507 }
508 #ifdef TLSDESC_BACKWARDS
509 /* Some archs (32-bit ARM at least) invert the order of
510 * the descriptor members. Fix them up here. */
511 size_t tmp = reloc_addr[0];
512 reloc_addr[0] = reloc_addr[1];
513 reloc_addr[1] = tmp;
514 #endif
515 break;
516 default:
517 error("Error relocating %s: unsupported relocation type %d",
518 dso->name, type);
519 if (runtime) longjmp(*rtld_fail, 1);
520 continue;
521 }
522 }
523 }
524
do_relr_relocs(struct dso * dso,size_t * relr,size_t relr_size)525 static void do_relr_relocs(struct dso *dso, size_t *relr, size_t relr_size)
526 {
527 unsigned char *base = dso->base;
528 size_t *reloc_addr;
529 for (; relr_size; relr++, relr_size-=sizeof(size_t))
530 if ((relr[0]&1) == 0) {
531 reloc_addr = laddr(dso, relr[0]);
532 *reloc_addr++ += (size_t)base;
533 } else {
534 int i = 0;
535 for (size_t bitmap=relr[0]; (bitmap>>=1); i++)
536 if (bitmap&1)
537 reloc_addr[i] += (size_t)base;
538 reloc_addr += 8*sizeof(size_t)-1;
539 }
540 }
541
redo_lazy_relocs()542 static void redo_lazy_relocs()
543 {
544 struct dso *p = lazy_head, *next;
545 lazy_head = 0;
546 for (; p; p=next) {
547 next = p->lazy_next;
548 size_t size = p->lazy_cnt*3*sizeof(size_t);
549 p->lazy_cnt = 0;
550 do_relocs(p, p->lazy, size, 3);
551 if (p->lazy_cnt) {
552 p->lazy_next = lazy_head;
553 lazy_head = p;
554 } else {
555 free(p->lazy);
556 p->lazy = 0;
557 p->lazy_next = 0;
558 }
559 }
560 }
561
562 /* A huge hack: to make up for the wastefulness of shared libraries
563 * needing at least a page of dirty memory even if they have no global
564 * data, we reclaim the gaps at the beginning and end of writable maps
565 * and "donate" them to the heap. */
566
reclaim(struct dso * dso,size_t start,size_t end)567 static void reclaim(struct dso *dso, size_t start, size_t end)
568 {
569 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
570 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
571 if (start >= end) return;
572 char *base = laddr_pg(dso, start);
573 __malloc_donate(base, base+(end-start));
574 }
575
reclaim_gaps(struct dso * dso)576 static void reclaim_gaps(struct dso *dso)
577 {
578 Phdr *ph = dso->phdr;
579 size_t phcnt = dso->phnum;
580
581 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
582 if (ph->p_type!=PT_LOAD) continue;
583 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
584 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
585 reclaim(dso, ph->p_vaddr+ph->p_memsz,
586 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
587 }
588 }
589
read_loop(int fd,void * p,size_t n)590 static ssize_t read_loop(int fd, void *p, size_t n)
591 {
592 for (size_t i=0; i<n; ) {
593 ssize_t l = read(fd, (char *)p+i, n-i);
594 if (l<0) {
595 if (errno==EINTR) continue;
596 else return -1;
597 }
598 if (l==0) return i;
599 i += l;
600 }
601 return n;
602 }
603
mmap_fixed(void * p,size_t n,int prot,int flags,int fd,off_t off)604 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
605 {
606 static int no_map_fixed;
607 char *q;
608 if (!n) return p;
609 if (!no_map_fixed) {
610 q = mmap(p, n, prot, flags|MAP_FIXED, fd, off);
611 if (!DL_NOMMU_SUPPORT || q != MAP_FAILED || errno != EINVAL)
612 return q;
613 no_map_fixed = 1;
614 }
615 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
616 if (flags & MAP_ANONYMOUS) {
617 memset(p, 0, n);
618 return p;
619 }
620 ssize_t r;
621 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
622 for (q=p; n; q+=r, off+=r, n-=r) {
623 r = read(fd, q, n);
624 if (r < 0 && errno != EINTR) return MAP_FAILED;
625 if (!r) {
626 memset(q, 0, n);
627 break;
628 }
629 }
630 return p;
631 }
632
unmap_library(struct dso * dso)633 static void unmap_library(struct dso *dso)
634 {
635 if (dso->loadmap) {
636 size_t i;
637 for (i=0; i<dso->loadmap->nsegs; i++) {
638 if (!dso->loadmap->segs[i].p_memsz)
639 continue;
640 munmap((void *)dso->loadmap->segs[i].addr,
641 dso->loadmap->segs[i].p_memsz);
642 }
643 free(dso->loadmap);
644 } else if (dso->map && dso->map_len) {
645 munmap(dso->map, dso->map_len);
646 }
647 }
648
verify_elf_magic(const Ehdr * eh)649 static int verify_elf_magic(const Ehdr* eh) {
650 return eh->e_ident[0] == ELFMAG0 &&
651 eh->e_ident[1] == ELFMAG1 &&
652 eh->e_ident[2] == ELFMAG2 &&
653 eh->e_ident[3] == ELFMAG3;
654 }
655
656 /* Verifies that an elf header's machine and class match the loader */
verify_elf_arch(const Ehdr * eh)657 static int verify_elf_arch(const Ehdr* eh) {
658 return eh->e_machine == ldso.elfmachine &&
659 eh->e_ident[EI_CLASS] == ldso.elfclass;
660 }
661
map_library(int fd,struct dso * dso)662 static void *map_library(int fd, struct dso *dso)
663 {
664 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
665 void *allocated_buf=0;
666 size_t phsize;
667 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
668 size_t this_min, this_max;
669 size_t nsegs = 0;
670 off_t off_start;
671 Ehdr *eh;
672 Phdr *ph, *ph0;
673 unsigned prot;
674 unsigned char *map=MAP_FAILED, *base;
675 size_t dyn=0;
676 size_t tls_image=0;
677 size_t i;
678
679 ssize_t l = read(fd, buf, sizeof buf);
680 eh = buf;
681 if (l<0) return 0;
682 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
683 goto noexec;
684 if (!verify_elf_magic(eh)) goto noexec;
685 if (!verify_elf_arch(eh)) goto noexec;
686 dso->elfmachine = eh->e_machine;
687 dso->elfclass = eh->e_ident[EI_CLASS];
688 phsize = eh->e_phentsize * eh->e_phnum;
689 if (phsize > sizeof buf - sizeof *eh) {
690 allocated_buf = malloc(phsize);
691 if (!allocated_buf) return 0;
692 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
693 if (l < 0) goto error;
694 if (l != phsize) goto noexec;
695 ph = ph0 = allocated_buf;
696 } else if (eh->e_phoff + phsize > l) {
697 l = pread(fd, buf+1, phsize, eh->e_phoff);
698 if (l < 0) goto error;
699 if (l != phsize) goto noexec;
700 ph = ph0 = (void *)(buf + 1);
701 } else {
702 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
703 }
704 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
705 if (ph->p_type == PT_DYNAMIC) {
706 dyn = ph->p_vaddr;
707 } else if (ph->p_type == PT_TLS) {
708 tls_image = ph->p_vaddr;
709 dso->tls.align = ph->p_align;
710 dso->tls.len = ph->p_filesz;
711 dso->tls.size = ph->p_memsz;
712 } else if (ph->p_type == PT_GNU_RELRO) {
713 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
714 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
715 } else if (ph->p_type == PT_GNU_STACK) {
716 if (!runtime && ph->p_memsz > __default_stacksize) {
717 __default_stacksize =
718 ph->p_memsz < DEFAULT_STACK_MAX ?
719 ph->p_memsz : DEFAULT_STACK_MAX;
720 }
721 }
722 if (ph->p_type != PT_LOAD) continue;
723 nsegs++;
724 if (ph->p_vaddr < addr_min) {
725 addr_min = ph->p_vaddr;
726 off_start = ph->p_offset;
727 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
728 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
729 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
730 }
731 if (ph->p_vaddr+ph->p_memsz > addr_max) {
732 addr_max = ph->p_vaddr+ph->p_memsz;
733 }
734 }
735 if (!dyn) goto noexec;
736 if (DL_FDPIC && !(eh->e_flags & FDPIC_CONSTDISP_FLAG)) {
737 dso->loadmap = calloc(1, sizeof *dso->loadmap
738 + nsegs * sizeof *dso->loadmap->segs);
739 if (!dso->loadmap) goto error;
740 dso->loadmap->nsegs = nsegs;
741 for (ph=ph0, i=0; i<nsegs; ph=(void *)((char *)ph+eh->e_phentsize)) {
742 if (ph->p_type != PT_LOAD) continue;
743 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
744 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
745 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
746 map = mmap(0, ph->p_memsz + (ph->p_vaddr & PAGE_SIZE-1),
747 prot, MAP_PRIVATE,
748 fd, ph->p_offset & -PAGE_SIZE);
749 if (map == MAP_FAILED) {
750 unmap_library(dso);
751 goto error;
752 }
753 dso->loadmap->segs[i].addr = (size_t)map +
754 (ph->p_vaddr & PAGE_SIZE-1);
755 dso->loadmap->segs[i].p_vaddr = ph->p_vaddr;
756 dso->loadmap->segs[i].p_memsz = ph->p_memsz;
757 i++;
758 if (prot & PROT_WRITE) {
759 size_t brk = (ph->p_vaddr & PAGE_SIZE-1)
760 + ph->p_filesz;
761 size_t pgbrk = brk + PAGE_SIZE-1 & -PAGE_SIZE;
762 size_t pgend = brk + ph->p_memsz - ph->p_filesz
763 + PAGE_SIZE-1 & -PAGE_SIZE;
764 if (pgend > pgbrk && mmap_fixed(map+pgbrk,
765 pgend-pgbrk, prot,
766 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
767 -1, off_start) == MAP_FAILED)
768 goto error;
769 memset(map + brk, 0, pgbrk-brk);
770 }
771 }
772 map = (void *)dso->loadmap->segs[0].addr;
773 map_len = 0;
774 goto done_mapping;
775 }
776 addr_max += PAGE_SIZE-1;
777 addr_max &= -PAGE_SIZE;
778 addr_min &= -PAGE_SIZE;
779 off_start &= -PAGE_SIZE;
780 map_len = addr_max - addr_min + off_start;
781 /* The first time, we map too much, possibly even more than
782 * the length of the file. This is okay because we will not
783 * use the invalid part; we just need to reserve the right
784 * amount of virtual address space to map over later. */
785 map = DL_NOMMU_SUPPORT
786 ? mmap((void *)addr_min, map_len, PROT_READ|PROT_WRITE|PROT_EXEC,
787 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
788 : mmap((void *)addr_min, map_len, prot,
789 MAP_PRIVATE, fd, off_start);
790 if (map==MAP_FAILED) goto error;
791 dso->map = map;
792 dso->map_len = map_len;
793 /* If the loaded file is not relocatable and the requested address is
794 * not available, then the load operation must fail. */
795 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
796 errno = EBUSY;
797 goto error;
798 }
799 base = map - addr_min;
800 dso->phdr = 0;
801 dso->phnum = 0;
802 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
803 if (ph->p_type != PT_LOAD) continue;
804 /* Check if the programs headers are in this load segment, and
805 * if so, record the address for use by dl_iterate_phdr. */
806 if (!dso->phdr && eh->e_phoff >= ph->p_offset
807 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
808 dso->phdr = (void *)(base + ph->p_vaddr
809 + (eh->e_phoff-ph->p_offset));
810 dso->phnum = eh->e_phnum;
811 dso->phentsize = eh->e_phentsize;
812 }
813 this_min = ph->p_vaddr & -PAGE_SIZE;
814 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
815 off_start = ph->p_offset & -PAGE_SIZE;
816 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
817 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
818 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
819 /* Reuse the existing mapping for the lowest-address LOAD */
820 if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
821 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
822 goto error;
823 if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
824 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
825 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
826 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
827 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)
828 goto error;
829 }
830 }
831 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
832 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
833 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
834 && errno != ENOSYS)
835 goto error;
836 break;
837 }
838 done_mapping:
839 dso->base = base;
840 dso->dynv = laddr(dso, dyn);
841 if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
842 free(allocated_buf);
843 return map;
844 noexec:
845 errno = ENOEXEC;
846 error:
847 if (map!=MAP_FAILED) unmap_library(dso);
848 free(allocated_buf);
849 return 0;
850 }
851
path_open_library(const char * name,const char * s,char * buf,size_t buf_size)852 static int path_open_library(const char *name, const char *s, char *buf, size_t buf_size)
853 {
854 size_t l;
855 int fd;
856 const char *p;
857 for (;;) {
858 s += strspn(s, ":\n");
859 p = s;
860 l = strcspn(s, ":\n");
861 if (l-1 >= INT_MAX) return -1;
862 s += l;
863 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, p, name) < buf_size) {
864 fd = open(buf, O_RDONLY|O_CLOEXEC);
865 if (fd < 0) {
866 switch (errno) {
867 case ENOENT:
868 case ENOTDIR:
869 case EACCES:
870 case ENAMETOOLONG:
871 /* Keep searching in path list. */
872 continue;
873 default:
874 /* Any negative value but -1 will
875 * inhibit further path search in
876 * load_library. */
877 return -2;
878 }
879 }
880 Ehdr eh;
881 ssize_t n = pread(fd, &eh, sizeof eh, 0);
882 /* If the elf file is invalid return -2 to inhibit
883 * further path search in load_library. */
884 if (n < 0 ||
885 n != sizeof eh ||
886 !verify_elf_magic(&eh)) {
887 close(fd);
888 return -2;
889 }
890 /* If the elf file has a valid header but is for the
891 * wrong architecture ignore it and keep searching the
892 * path list. */
893 if (!verify_elf_arch(&eh)) {
894 close(fd);
895 continue;
896 }
897 return fd;
898 }
899 }
900 }
901
fixup_rpath(struct dso * p,char * buf,size_t buf_size)902 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
903 {
904 size_t n, l;
905 const char *s, *t, *origin;
906 char *d;
907 if (p->rpath || !p->rpath_orig) return 0;
908 if (!strchr(p->rpath_orig, '$')) {
909 p->rpath = p->rpath_orig;
910 return 0;
911 }
912 n = 0;
913 s = p->rpath_orig;
914 while ((t=strchr(s, '$'))) {
915 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
916 return 0;
917 s = t+1;
918 n++;
919 }
920 if (n > SSIZE_MAX/PATH_MAX) return 0;
921
922 if (p->kernel_mapped) {
923 /* $ORIGIN searches cannot be performed for the main program
924 * when it is suid/sgid/AT_SECURE. This is because the
925 * pathname is under the control of the caller of execve.
926 * For libraries, however, $ORIGIN can be processed safely
927 * since the library's pathname came from a trusted source
928 * (either system paths or a call to dlopen). */
929 if (libc.secure)
930 return 0;
931 l = readlink("/proc/self/exe", buf, buf_size);
932 if (l == -1) switch (errno) {
933 case ENOENT:
934 case ENOTDIR:
935 case EACCES:
936 return 0;
937 default:
938 return -1;
939 }
940 if (l >= buf_size)
941 return 0;
942 buf[l] = 0;
943 origin = buf;
944 } else {
945 origin = p->name;
946 }
947 t = strrchr(origin, '/');
948 if (t) {
949 l = t-origin;
950 } else {
951 /* Normally p->name will always be an absolute or relative
952 * pathname containing at least one '/' character, but in the
953 * case where ldso was invoked as a command to execute a
954 * program in the working directory, app.name may not. Fix. */
955 origin = ".";
956 l = 1;
957 }
958 /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
959 if (libc.secure && *origin != '/')
960 return 0;
961 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
962 if (!p->rpath) return -1;
963
964 d = p->rpath;
965 s = p->rpath_orig;
966 while ((t=strchr(s, '$'))) {
967 memcpy(d, s, t-s);
968 d += t-s;
969 memcpy(d, origin, l);
970 d += l;
971 /* It was determined previously that the '$' is followed
972 * either by "ORIGIN" or "{ORIGIN}". */
973 s = t + 7 + 2*(t[1]=='{');
974 }
975 strcpy(d, s);
976 return 0;
977 }
978
decode_dyn(struct dso * p)979 static void decode_dyn(struct dso *p)
980 {
981 size_t dyn[DYN_CNT];
982 decode_vec(p->dynv, dyn, DYN_CNT);
983 p->syms = laddr(p, dyn[DT_SYMTAB]);
984 p->strings = laddr(p, dyn[DT_STRTAB]);
985 if (dyn[0]&(1<<DT_HASH))
986 p->hashtab = laddr(p, dyn[DT_HASH]);
987 if (dyn[0]&(1<<DT_RPATH))
988 p->rpath_orig = p->strings + dyn[DT_RPATH];
989 if (dyn[0]&(1<<DT_RUNPATH))
990 p->rpath_orig = p->strings + dyn[DT_RUNPATH];
991 if (dyn[0]&(1<<DT_PLTGOT))
992 p->got = laddr(p, dyn[DT_PLTGOT]);
993 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
994 p->ghashtab = laddr(p, *dyn);
995 if (search_vec(p->dynv, dyn, DT_VERSYM))
996 p->versym = laddr(p, *dyn);
997 }
998
count_syms(struct dso * p)999 static size_t count_syms(struct dso *p)
1000 {
1001 if (p->hashtab) return p->hashtab[1];
1002
1003 size_t nsym, i;
1004 uint32_t *buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1005 uint32_t *hashval;
1006 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1007 if (buckets[i] > nsym)
1008 nsym = buckets[i];
1009 }
1010 if (nsym) {
1011 hashval = buckets + p->ghashtab[0] + (nsym - p->ghashtab[1]);
1012 do nsym++;
1013 while (!(*hashval++ & 1));
1014 }
1015 return nsym;
1016 }
1017
dl_mmap(size_t n)1018 static void *dl_mmap(size_t n)
1019 {
1020 void *p;
1021 int prot = PROT_READ|PROT_WRITE, flags = MAP_ANONYMOUS|MAP_PRIVATE;
1022 #ifdef SYS_mmap2
1023 p = (void *)__syscall(SYS_mmap2, 0, n, prot, flags, -1, 0);
1024 #else
1025 p = (void *)__syscall(SYS_mmap, 0, n, prot, flags, -1, 0);
1026 #endif
1027 return (unsigned long)p > -4096UL ? 0 : p;
1028 }
1029
makefuncdescs(struct dso * p)1030 static void makefuncdescs(struct dso *p)
1031 {
1032 static int self_done;
1033 size_t nsym = count_syms(p);
1034 size_t i, size = nsym * sizeof(*p->funcdescs);
1035
1036 if (!self_done) {
1037 p->funcdescs = dl_mmap(size);
1038 self_done = 1;
1039 } else {
1040 p->funcdescs = malloc(size);
1041 }
1042 if (!p->funcdescs) {
1043 if (!runtime) a_crash();
1044 error("Error allocating function descriptors for %s", p->name);
1045 longjmp(*rtld_fail, 1);
1046 }
1047 for (i=0; i<nsym; i++) {
1048 if ((p->syms[i].st_info&0xf)==STT_FUNC && p->syms[i].st_shndx) {
1049 p->funcdescs[i].addr = laddr(p, p->syms[i].st_value);
1050 p->funcdescs[i].got = p->got;
1051 } else {
1052 p->funcdescs[i].addr = 0;
1053 p->funcdescs[i].got = 0;
1054 }
1055 }
1056 }
1057
load_library(const char * name,struct dso * needed_by)1058 static struct dso *load_library(const char *name, struct dso *needed_by)
1059 {
1060 char buf[2*NAME_MAX+2];
1061 const char *pathname;
1062 unsigned char *map;
1063 struct dso *p, temp_dso = {0};
1064 int fd;
1065 struct stat st;
1066 size_t alloc_size;
1067 int n_th = 0;
1068 int is_self = 0;
1069
1070 if (!*name) {
1071 errno = EINVAL;
1072 return 0;
1073 }
1074
1075 /* Catch and block attempts to reload the implementation itself */
1076 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
1077 static const char reserved[] =
1078 "c.c_musl.pthread.rt.m.dl.util.xnet.";
1079 const char *rp, *next;
1080 for (rp=reserved; *rp; rp=next) {
1081 next = strchr(rp, '.') + 1;
1082 if (strncmp(name+3, rp, next-rp) == 0)
1083 break;
1084 }
1085 if (*rp) {
1086 if (ldd_mode) {
1087 /* Track which names have been resolved
1088 * and only report each one once. */
1089 static unsigned reported;
1090 unsigned mask = 1U<<(rp-reserved);
1091 if (!(reported & mask)) {
1092 reported |= mask;
1093 dprintf(1, "\t%s => %s (%p)\n",
1094 name, ldso.name,
1095 ldso.base);
1096 }
1097 }
1098 is_self = 1;
1099 }
1100 }
1101 if (!strcmp(name, ldso.name)) is_self = 1;
1102 if (is_self) {
1103 if (!ldso.prev) {
1104 tail->next = &ldso;
1105 ldso.prev = tail;
1106 tail = &ldso;
1107 }
1108 return &ldso;
1109 }
1110 if (strchr(name, '/')) {
1111 pathname = name;
1112 fd = open(name, O_RDONLY|O_CLOEXEC);
1113 } else {
1114 /* Search for the name to see if it's already loaded */
1115 for (p=head->next; p; p=p->next) {
1116 if (p->shortname && !strcmp(p->shortname, name)) {
1117 return p;
1118 }
1119 }
1120 if (strlen(name) > NAME_MAX) return 0;
1121 fd = -1;
1122 if (env_path) fd = path_open_library(name, env_path, buf, sizeof buf);
1123 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
1124 if (fixup_rpath(p, buf, sizeof buf) < 0)
1125 fd = -2; /* Inhibit further search. */
1126 if (p->rpath)
1127 fd = path_open_library(name, p->rpath, buf, sizeof buf);
1128 }
1129 if (fd == -1) {
1130 if (!sys_path) {
1131 char *prefix = 0;
1132 size_t prefix_len;
1133 if (ldso.name[0]=='/') {
1134 char *s, *t, *z;
1135 for (s=t=z=ldso.name; *s; s++)
1136 if (*s=='/') z=t, t=s;
1137 prefix_len = z-ldso.name;
1138 if (prefix_len < PATH_MAX)
1139 prefix = ldso.name;
1140 }
1141 if (!prefix) {
1142 prefix = "";
1143 prefix_len = 0;
1144 }
1145 char etc_ldso_path[prefix_len + 1
1146 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
1147 snprintf(etc_ldso_path, sizeof etc_ldso_path,
1148 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
1149 (int)prefix_len, prefix);
1150 fd = open(etc_ldso_path, O_RDONLY|O_CLOEXEC);
1151 if (fd>=0) {
1152 size_t n = 0;
1153 if (!fstat(fd, &st)) n = st.st_size;
1154 if ((sys_path = malloc(n+1)))
1155 sys_path[n] = 0;
1156 if (!sys_path || read_loop(fd, sys_path, n)<0) {
1157 free(sys_path);
1158 sys_path = "";
1159 }
1160 close(fd);
1161 } else if (errno != ENOENT) {
1162 sys_path = "";
1163 }
1164 }
1165 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
1166 fd = path_open_library(name, sys_path, buf, sizeof buf);
1167 }
1168 pathname = buf;
1169 }
1170 if (fd < 0) return 0;
1171 if (fstat(fd, &st) < 0) {
1172 close(fd);
1173 return 0;
1174 }
1175 for (p=head->next; p; p=p->next) {
1176 if (p->dev == st.st_dev && p->ino == st.st_ino) {
1177 /* If this library was previously loaded with a
1178 * pathname but a search found the same inode,
1179 * setup its shortname so it can be found by name. */
1180 if (!p->shortname && pathname != name)
1181 p->shortname = strrchr(p->name, '/')+1;
1182 close(fd);
1183 return p;
1184 }
1185 }
1186 map = noload ? 0 : map_library(fd, &temp_dso);
1187 close(fd);
1188 if (!map) return 0;
1189
1190 /* Avoid the danger of getting two versions of libc mapped into the
1191 * same process when an absolute pathname was used. The symbols
1192 * checked are chosen to catch both musl and glibc, and to avoid
1193 * false positives from interposition-hack libraries. */
1194 decode_dyn(&temp_dso);
1195 if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
1196 find_sym(&temp_dso, "stdin", 1).sym) {
1197 unmap_library(&temp_dso);
1198 return load_library(STRINGIFY(LIBC_SONAME), needed_by);
1199 }
1200 /* Past this point, if we haven't reached runtime yet, ldso has
1201 * committed either to use the mapped library or to abort execution.
1202 * Unmapping is not possible, so we can safely reclaim gaps. */
1203 if (!runtime) reclaim_gaps(&temp_dso);
1204
1205 /* Allocate storage for the new DSO. When there is TLS, this
1206 * storage must include a reservation for all pre-existing
1207 * threads to obtain copies of both the new TLS, and an
1208 * extended DTV capable of storing an additional slot for
1209 * the newly-loaded DSO. */
1210 alloc_size = sizeof *p + strlen(pathname) + 1;
1211 if (runtime && temp_dso.tls.image) {
1212 size_t per_th = temp_dso.tls.size + temp_dso.tls.align
1213 + sizeof(void *) * (tls_cnt+3);
1214 n_th = libc.threads_minus_1 + 1;
1215 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
1216 else alloc_size += n_th * per_th;
1217 }
1218 p = calloc(1, alloc_size);
1219 if (!p) {
1220 unmap_library(&temp_dso);
1221 return 0;
1222 }
1223 memcpy(p, &temp_dso, sizeof temp_dso);
1224 p->dev = st.st_dev;
1225 p->ino = st.st_ino;
1226 p->needed_by = needed_by;
1227 p->name = p->buf;
1228 p->runtime_loaded = runtime;
1229 strcpy(p->name, pathname);
1230 /* Add a shortname only if name arg was not an explicit pathname. */
1231 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
1232 if (p->tls.image) {
1233 p->tls_id = ++tls_cnt;
1234 tls_align = MAXP2(tls_align, p->tls.align);
1235 #ifdef TLS_ABOVE_TP
1236 p->tls.offset = tls_offset + ( (p->tls.align-1) &
1237 (-tls_offset + (uintptr_t)p->tls.image) );
1238 tls_offset = p->tls.offset + p->tls.size;
1239 #else
1240 tls_offset += p->tls.size + p->tls.align - 1;
1241 tls_offset -= (tls_offset + (uintptr_t)p->tls.image)
1242 & (p->tls.align-1);
1243 p->tls.offset = tls_offset;
1244 #endif
1245 p->new_dtv = (void *)(-sizeof(size_t) &
1246 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
1247 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
1248 if (tls_tail) tls_tail->next = &p->tls;
1249 else libc.tls_head = &p->tls;
1250 tls_tail = &p->tls;
1251 }
1252
1253 tail->next = p;
1254 p->prev = tail;
1255 tail = p;
1256
1257 if (DL_FDPIC) makefuncdescs(p);
1258
1259 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
1260
1261 return p;
1262 }
1263
load_direct_deps(struct dso * p)1264 static void load_direct_deps(struct dso *p)
1265 {
1266 size_t i, cnt=0;
1267
1268 if (p->deps) return;
1269 /* For head, all preloads are direct pseudo-dependencies.
1270 * Count and include them now to avoid realloc later. */
1271 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1272 cnt++;
1273 for (i=0; p->dynv[i]; i+=2)
1274 if (p->dynv[i] == DT_NEEDED) cnt++;
1275 /* Use builtin buffer for apps with no external deps, to
1276 * preserve property of no runtime failure paths. */
1277 p->deps = (p==head && cnt<2) ? builtin_deps :
1278 calloc(cnt+1, sizeof *p->deps);
1279 if (!p->deps) {
1280 error("Error loading dependencies for %s", p->name);
1281 if (runtime) longjmp(*rtld_fail, 1);
1282 }
1283 cnt=0;
1284 if (p==head) for (struct dso *q=p->next; q; q=q->next)
1285 p->deps[cnt++] = q;
1286 for (i=0; p->dynv[i]; i+=2) {
1287 if (p->dynv[i] != DT_NEEDED) continue;
1288 struct dso *dep = load_library(p->strings + p->dynv[i+1], p);
1289 if (!dep) {
1290 error("Error loading shared library %s: %m (needed by %s)",
1291 p->strings + p->dynv[i+1], p->name);
1292 if (runtime) longjmp(*rtld_fail, 1);
1293 continue;
1294 }
1295 p->deps[cnt++] = dep;
1296 }
1297 p->deps[cnt] = 0;
1298 p->ndeps_direct = cnt;
1299 }
1300
load_deps(struct dso * p)1301 static void load_deps(struct dso *p)
1302 {
1303 if (p->deps) return;
1304 for (; p; p=p->next)
1305 load_direct_deps(p);
1306 }
1307
extend_bfs_deps(struct dso * p)1308 static void extend_bfs_deps(struct dso *p)
1309 {
1310 size_t i, j, cnt, ndeps_all;
1311 struct dso **tmp;
1312
1313 /* Can't use realloc if the original p->deps was allocated at
1314 * program entry and malloc has been replaced, or if it's
1315 * the builtin non-allocated trivial main program deps array. */
1316 int no_realloc = (__malloc_replaced && !p->runtime_loaded)
1317 || p->deps == builtin_deps;
1318
1319 if (p->bfs_built) return;
1320 ndeps_all = p->ndeps_direct;
1321
1322 /* Mark existing (direct) deps so they won't be duplicated. */
1323 for (i=0; p->deps[i]; i++)
1324 p->deps[i]->mark = 1;
1325
1326 /* For each dependency already in the list, copy its list of direct
1327 * dependencies to the list, excluding any items already in the
1328 * list. Note that the list this loop iterates over will grow during
1329 * the loop, but since duplicates are excluded, growth is bounded. */
1330 for (i=0; p->deps[i]; i++) {
1331 struct dso *dep = p->deps[i];
1332 for (j=cnt=0; j<dep->ndeps_direct; j++)
1333 if (!dep->deps[j]->mark) cnt++;
1334 tmp = no_realloc ?
1335 malloc(sizeof(*tmp) * (ndeps_all+cnt+1)) :
1336 realloc(p->deps, sizeof(*tmp) * (ndeps_all+cnt+1));
1337 if (!tmp) {
1338 error("Error recording dependencies for %s", p->name);
1339 if (runtime) longjmp(*rtld_fail, 1);
1340 continue;
1341 }
1342 if (no_realloc) {
1343 memcpy(tmp, p->deps, sizeof(*tmp) * (ndeps_all+1));
1344 no_realloc = 0;
1345 }
1346 p->deps = tmp;
1347 for (j=0; j<dep->ndeps_direct; j++) {
1348 if (dep->deps[j]->mark) continue;
1349 dep->deps[j]->mark = 1;
1350 p->deps[ndeps_all++] = dep->deps[j];
1351 }
1352 p->deps[ndeps_all] = 0;
1353 }
1354 p->bfs_built = 1;
1355 for (p=head; p; p=p->next)
1356 p->mark = 0;
1357 }
1358
load_preload(char * s)1359 static void load_preload(char *s)
1360 {
1361 int tmp;
1362 char *z;
1363 for (z=s; *z; s=z) {
1364 for ( ; *s && (isspace(*s) || *s==':'); s++);
1365 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
1366 tmp = *z;
1367 *z = 0;
1368 load_library(s, 0);
1369 *z = tmp;
1370 }
1371 }
1372
add_syms(struct dso * p)1373 static void add_syms(struct dso *p)
1374 {
1375 if (!p->syms_next && syms_tail != p) {
1376 syms_tail->syms_next = p;
1377 syms_tail = p;
1378 }
1379 }
1380
revert_syms(struct dso * old_tail)1381 static void revert_syms(struct dso *old_tail)
1382 {
1383 struct dso *p, *next;
1384 /* Chop off the tail of the list of dsos that participate in
1385 * the global symbol table, reverting them to RTLD_LOCAL. */
1386 for (p=old_tail; p; p=next) {
1387 next = p->syms_next;
1388 p->syms_next = 0;
1389 }
1390 syms_tail = old_tail;
1391 }
1392
do_mips_relocs(struct dso * p,size_t * got)1393 static void do_mips_relocs(struct dso *p, size_t *got)
1394 {
1395 size_t i, j, rel[2];
1396 unsigned char *base = p->base;
1397 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
1398 if (p==&ldso) {
1399 got += i;
1400 } else {
1401 while (i--) *got++ += (size_t)base;
1402 }
1403 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
1404 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
1405 Sym *sym = p->syms + j;
1406 rel[0] = (unsigned char *)got - base;
1407 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
1408 rel[1] = R_INFO(sym-p->syms, R_MIPS_JUMP_SLOT);
1409 do_relocs(p, rel, sizeof rel, 2);
1410 }
1411 }
1412
reloc_all(struct dso * p)1413 static void reloc_all(struct dso *p)
1414 {
1415 size_t dyn[DYN_CNT];
1416 for (; p; p=p->next) {
1417 if (p->relocated) continue;
1418 decode_vec(p->dynv, dyn, DYN_CNT);
1419 if (NEED_MIPS_GOT_RELOCS)
1420 do_mips_relocs(p, laddr(p, dyn[DT_PLTGOT]));
1421 do_relocs(p, laddr(p, dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
1422 2+(dyn[DT_PLTREL]==DT_RELA));
1423 do_relocs(p, laddr(p, dyn[DT_REL]), dyn[DT_RELSZ], 2);
1424 do_relocs(p, laddr(p, dyn[DT_RELA]), dyn[DT_RELASZ], 3);
1425 if (!DL_FDPIC)
1426 do_relr_relocs(p, laddr(p, dyn[DT_RELR]), dyn[DT_RELRSZ]);
1427
1428 if (head != &ldso && p->relro_start != p->relro_end) {
1429 long ret = __syscall(SYS_mprotect, laddr(p, p->relro_start),
1430 p->relro_end-p->relro_start, PROT_READ);
1431 if (ret != 0 && ret != -ENOSYS) {
1432 error("Error relocating %s: RELRO protection failed: %m",
1433 p->name);
1434 if (runtime) longjmp(*rtld_fail, 1);
1435 }
1436 }
1437
1438 p->relocated = 1;
1439 }
1440 }
1441
kernel_mapped_dso(struct dso * p)1442 static void kernel_mapped_dso(struct dso *p)
1443 {
1444 size_t min_addr = -1, max_addr = 0, cnt;
1445 Phdr *ph = p->phdr;
1446 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
1447 if (ph->p_type == PT_DYNAMIC) {
1448 p->dynv = laddr(p, ph->p_vaddr);
1449 } else if (ph->p_type == PT_GNU_RELRO) {
1450 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
1451 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
1452 } else if (ph->p_type == PT_GNU_STACK) {
1453 if (!runtime && ph->p_memsz > __default_stacksize) {
1454 __default_stacksize =
1455 ph->p_memsz < DEFAULT_STACK_MAX ?
1456 ph->p_memsz : DEFAULT_STACK_MAX;
1457 }
1458 }
1459 if (ph->p_type != PT_LOAD) continue;
1460 if (ph->p_vaddr < min_addr)
1461 min_addr = ph->p_vaddr;
1462 if (ph->p_vaddr+ph->p_memsz > max_addr)
1463 max_addr = ph->p_vaddr+ph->p_memsz;
1464 }
1465 min_addr &= -PAGE_SIZE;
1466 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
1467 p->map = p->base + min_addr;
1468 p->map_len = max_addr - min_addr;
1469 p->kernel_mapped = 1;
1470 }
1471
__libc_exit_fini()1472 void __libc_exit_fini()
1473 {
1474 struct dso *p;
1475 size_t dyn[DYN_CNT];
1476 pthread_t self = __pthread_self();
1477
1478 /* Take both locks before setting shutting_down, so that
1479 * either lock is sufficient to read its value. The lock
1480 * order matches that in dlopen to avoid deadlock. */
1481 pthread_rwlock_wrlock(&lock);
1482 pthread_mutex_lock(&init_fini_lock);
1483 shutting_down = 1;
1484 pthread_rwlock_unlock(&lock);
1485 for (p=fini_head; p; p=p->fini_next) {
1486 while (p->ctor_visitor && p->ctor_visitor!=self)
1487 pthread_cond_wait(&ctor_cond, &init_fini_lock);
1488 if (!p->constructed) continue;
1489 decode_vec(p->dynv, dyn, DYN_CNT);
1490 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
1491 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
1492 size_t *fn = (size_t *)laddr(p, dyn[DT_FINI_ARRAY])+n;
1493 while (n--) ((void (*)(void))*--fn)();
1494 }
1495 #ifndef NO_LEGACY_INITFINI
1496 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1497 fpaddr(p, dyn[DT_FINI])();
1498 #endif
1499 }
1500 }
1501
__ldso_atfork(int who)1502 void __ldso_atfork(int who)
1503 {
1504 if (who<0) {
1505 pthread_rwlock_wrlock(&lock);
1506 pthread_mutex_lock(&init_fini_lock);
1507 } else {
1508 pthread_mutex_unlock(&init_fini_lock);
1509 pthread_rwlock_unlock(&lock);
1510 }
1511 }
1512
queue_ctors(struct dso * dso)1513 static struct dso **queue_ctors(struct dso *dso)
1514 {
1515 size_t cnt, qpos, spos, i;
1516 struct dso *p, **queue, **stack;
1517
1518 if (ldd_mode) return 0;
1519
1520 /* Bound on queue size is the total number of indirect deps.
1521 * If a bfs deps list was built, we can use it. Otherwise,
1522 * bound by the total number of DSOs, which is always safe and
1523 * is reasonable we use it (for main app at startup). */
1524 if (dso->bfs_built) {
1525 for (cnt=0; dso->deps[cnt]; cnt++)
1526 dso->deps[cnt]->mark = 0;
1527 cnt++; /* self, not included in deps */
1528 } else {
1529 for (cnt=0, p=head; p; cnt++, p=p->next)
1530 p->mark = 0;
1531 }
1532 cnt++; /* termination slot */
1533 if (dso==head && cnt <= countof(builtin_ctor_queue))
1534 queue = builtin_ctor_queue;
1535 else
1536 queue = calloc(cnt, sizeof *queue);
1537
1538 if (!queue) {
1539 error("Error allocating constructor queue: %m\n");
1540 if (runtime) longjmp(*rtld_fail, 1);
1541 return 0;
1542 }
1543
1544 /* Opposite ends of the allocated buffer serve as an output queue
1545 * and a working stack. Setup initial stack with just the argument
1546 * dso and initial queue empty... */
1547 stack = queue;
1548 qpos = 0;
1549 spos = cnt;
1550 stack[--spos] = dso;
1551 dso->next_dep = 0;
1552 dso->mark = 1;
1553
1554 /* Then perform pseudo-DFS sort, but ignoring circular deps. */
1555 while (spos<cnt) {
1556 p = stack[spos++];
1557 while (p->next_dep < p->ndeps_direct) {
1558 if (p->deps[p->next_dep]->mark) {
1559 p->next_dep++;
1560 } else {
1561 stack[--spos] = p;
1562 p = p->deps[p->next_dep];
1563 p->next_dep = 0;
1564 p->mark = 1;
1565 }
1566 }
1567 queue[qpos++] = p;
1568 }
1569 queue[qpos] = 0;
1570 for (i=0; i<qpos; i++) queue[i]->mark = 0;
1571 for (i=0; i<qpos; i++)
1572 if (queue[i]->ctor_visitor && queue[i]->ctor_visitor->tid < 0) {
1573 error("State of %s is inconsistent due to multithreaded fork\n",
1574 queue[i]->name);
1575 free(queue);
1576 if (runtime) longjmp(*rtld_fail, 1);
1577 }
1578
1579 return queue;
1580 }
1581
do_init_fini(struct dso ** queue)1582 static void do_init_fini(struct dso **queue)
1583 {
1584 struct dso *p;
1585 size_t dyn[DYN_CNT], i;
1586 pthread_t self = __pthread_self();
1587
1588 pthread_mutex_lock(&init_fini_lock);
1589 for (i=0; (p=queue[i]); i++) {
1590 while ((p->ctor_visitor && p->ctor_visitor!=self) || shutting_down)
1591 pthread_cond_wait(&ctor_cond, &init_fini_lock);
1592 if (p->ctor_visitor || p->constructed)
1593 continue;
1594 p->ctor_visitor = self;
1595
1596 decode_vec(p->dynv, dyn, DYN_CNT);
1597 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1598 p->fini_next = fini_head;
1599 fini_head = p;
1600 }
1601
1602 pthread_mutex_unlock(&init_fini_lock);
1603
1604 #ifndef NO_LEGACY_INITFINI
1605 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1606 fpaddr(p, dyn[DT_INIT])();
1607 #endif
1608 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1609 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1610 size_t *fn = laddr(p, dyn[DT_INIT_ARRAY]);
1611 while (n--) ((void (*)(void))*fn++)();
1612 }
1613
1614 pthread_mutex_lock(&init_fini_lock);
1615 p->ctor_visitor = 0;
1616 p->constructed = 1;
1617 pthread_cond_broadcast(&ctor_cond);
1618 }
1619 pthread_mutex_unlock(&init_fini_lock);
1620 }
1621
__libc_start_init(void)1622 void __libc_start_init(void)
1623 {
1624 do_init_fini(main_ctor_queue);
1625 if (!__malloc_replaced && main_ctor_queue != builtin_ctor_queue)
1626 free(main_ctor_queue);
1627 main_ctor_queue = 0;
1628 }
1629
dl_debug_state(void)1630 static void dl_debug_state(void)
1631 {
1632 if (exe_dl_debug_state)
1633 exe_dl_debug_state();
1634 }
1635
1636 weak_alias(dl_debug_state, _dl_debug_state);
1637
__init_tls(size_t * auxv)1638 void __init_tls(size_t *auxv)
1639 {
1640 }
1641
update_tls_size()1642 static void update_tls_size()
1643 {
1644 libc.tls_cnt = tls_cnt;
1645 libc.tls_align = tls_align;
1646 libc.tls_size = ALIGN(
1647 (1+tls_cnt) * sizeof(void *) +
1648 tls_offset +
1649 sizeof(struct pthread) +
1650 tls_align * 2,
1651 tls_align);
1652 }
1653
install_new_tls(void)1654 static void install_new_tls(void)
1655 {
1656 sigset_t set;
1657 pthread_t self = __pthread_self(), td;
1658 struct dso *dtv_provider = container_of(tls_tail, struct dso, tls);
1659 uintptr_t (*newdtv)[tls_cnt+1] = (void *)dtv_provider->new_dtv;
1660 struct dso *p;
1661 size_t i, j;
1662 size_t old_cnt = self->dtv[0];
1663
1664 __block_app_sigs(&set);
1665 __tl_lock();
1666 /* Copy existing dtv contents from all existing threads. */
1667 for (i=0, td=self; !i || td!=self; i++, td=td->next) {
1668 memcpy(newdtv+i, td->dtv,
1669 (old_cnt+1)*sizeof(uintptr_t));
1670 newdtv[i][0] = tls_cnt;
1671 }
1672 /* Install new dtls into the enlarged, uninstalled dtv copies. */
1673 for (p=head; ; p=p->next) {
1674 if (p->tls_id <= old_cnt) continue;
1675 unsigned char *mem = p->new_tls;
1676 for (j=0; j<i; j++) {
1677 unsigned char *new = mem;
1678 new += ((uintptr_t)p->tls.image - (uintptr_t)mem)
1679 & (p->tls.align-1);
1680 memcpy(new, p->tls.image, p->tls.len);
1681 newdtv[j][p->tls_id] =
1682 (uintptr_t)new + DTP_OFFSET;
1683 mem += p->tls.size + p->tls.align;
1684 }
1685 if (p->tls_id == tls_cnt) break;
1686 }
1687
1688 /* Broadcast barrier to ensure contents of new dtv is visible
1689 * if the new dtv pointer is. The __membarrier function has a
1690 * fallback emulation using signals for kernels that lack the
1691 * feature at the syscall level. */
1692
1693 __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED, 0);
1694
1695 /* Install new dtv for each thread. */
1696 for (j=0, td=self; !j || td!=self; j++, td=td->next) {
1697 td->dtv = newdtv[j];
1698 }
1699
1700 __tl_unlock();
1701 __restore_sigs(&set);
1702 }
1703
1704 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1705 * following stage 2 and stage 3 functions via primitive symbolic lookup
1706 * since it does not have access to their addresses to begin with. */
1707
1708 /* Stage 2 of the dynamic linker is called after relative relocations
1709 * have been processed. It can make function calls to static functions
1710 * and access string literals and static data, but cannot use extern
1711 * symbols. Its job is to perform symbolic relocations on the dynamic
1712 * linker itself, but some of the relocations performed may need to be
1713 * replaced later due to copy relocations in the main program. */
1714
__dls2(unsigned char * base,size_t * sp)1715 hidden void __dls2(unsigned char *base, size_t *sp)
1716 {
1717 size_t *auxv;
1718 for (auxv=sp+1+*sp+1; *auxv; auxv++);
1719 auxv++;
1720 if (DL_FDPIC) {
1721 void *p1 = (void *)sp[-2];
1722 void *p2 = (void *)sp[-1];
1723 if (!p1) {
1724 size_t aux[AUX_CNT];
1725 decode_vec(auxv, aux, AUX_CNT);
1726 if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
1727 else ldso.base = (void *)(aux[AT_PHDR] & -4096);
1728 }
1729 app_loadmap = p2 ? p1 : 0;
1730 ldso.loadmap = p2 ? p2 : p1;
1731 ldso.base = laddr(&ldso, 0);
1732 } else {
1733 ldso.base = base;
1734 }
1735 Ehdr *ehdr = (void *)ldso.base;
1736 ldso.name = ldso.shortname = STRINGIFY(LIBC_SONAME);
1737 ldso.phnum = ehdr->e_phnum;
1738 ldso.phdr = laddr(&ldso, ehdr->e_phoff);
1739 ldso.phentsize = ehdr->e_phentsize;
1740 ldso.elfmachine = ehdr->e_machine;
1741 ldso.elfclass = ehdr->e_ident[EI_CLASS];
1742 kernel_mapped_dso(&ldso);
1743 decode_dyn(&ldso);
1744
1745 if (DL_FDPIC) makefuncdescs(&ldso);
1746
1747 /* Prepare storage for to save clobbered REL addends so they
1748 * can be reused in stage 3. There should be very few. If
1749 * something goes wrong and there are a huge number, abort
1750 * instead of risking stack overflow. */
1751 size_t dyn[DYN_CNT];
1752 decode_vec(ldso.dynv, dyn, DYN_CNT);
1753 size_t *rel = laddr(&ldso, dyn[DT_REL]);
1754 size_t rel_size = dyn[DT_RELSZ];
1755 size_t symbolic_rel_cnt = 0;
1756 apply_addends_to = rel;
1757 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1758 if (!IS_RELATIVE(rel[1], ldso.syms)) symbolic_rel_cnt++;
1759 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1760 size_t addends[symbolic_rel_cnt+1];
1761 saved_addends = addends;
1762
1763 head = &ldso;
1764 reloc_all(&ldso);
1765
1766 ldso.relocated = 0;
1767
1768 /* Call dynamic linker stage-2b, __dls2b, looking it up
1769 * symbolically as a barrier against moving the address
1770 * load across the above relocation processing. */
1771 struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0);
1772 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp, auxv);
1773 else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp, auxv);
1774 }
1775
1776 /* Stage 2b sets up a valid thread pointer, which requires relocations
1777 * completed in stage 2, and on which stage 3 is permitted to depend.
1778 * This is done as a separate stage, with symbolic lookup as a barrier,
1779 * so that loads of the thread pointer and &errno can be pure/const and
1780 * thereby hoistable. */
1781
__dls2b(size_t * sp,size_t * auxv)1782 void __dls2b(size_t *sp, size_t *auxv)
1783 {
1784 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1785 * use during dynamic linking. If possible it will also serve as the
1786 * thread pointer at runtime. */
1787 search_vec(auxv, &__hwcap, AT_HWCAP);
1788 libc.auxv = auxv;
1789 libc.tls_size = sizeof builtin_tls;
1790 libc.tls_align = tls_align;
1791 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1792 a_crash();
1793 }
1794
1795 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1796 if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp, auxv);
1797 else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp, auxv);
1798 }
1799
1800 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1801 * fully functional. Its job is to load (if not already loaded) and
1802 * process dependencies and relocations for the main application and
1803 * transfer control to its entry point. */
1804
__dls3(size_t * sp,size_t * auxv)1805 void __dls3(size_t *sp, size_t *auxv)
1806 {
1807 static struct dso app, vdso;
1808 size_t aux[AUX_CNT];
1809 size_t i;
1810 char *env_preload=0;
1811 char *replace_argv0=0;
1812 size_t vdso_base;
1813 int argc = *sp;
1814 char **argv = (void *)(sp+1);
1815 char **argv_orig = argv;
1816 char **envp = argv+argc+1;
1817
1818 /* Find aux vector just past environ[] and use it to initialize
1819 * global data that may be needed before we can make syscalls. */
1820 __environ = envp;
1821 decode_vec(auxv, aux, AUX_CNT);
1822 search_vec(auxv, &__sysinfo, AT_SYSINFO);
1823 __pthread_self()->sysinfo = __sysinfo;
1824 libc.page_size = aux[AT_PAGESZ];
1825 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1826 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1827
1828 /* Only trust user/env if kernel says we're not suid/sgid */
1829 if (!libc.secure) {
1830 env_path = getenv("LD_LIBRARY_PATH");
1831 env_preload = getenv("LD_PRELOAD");
1832 }
1833
1834 /* Activate error handler function */
1835 error = error_impl;
1836
1837 /* If the main program was already loaded by the kernel,
1838 * AT_PHDR will point to some location other than the dynamic
1839 * linker's program headers. */
1840 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1841 size_t interp_off = 0;
1842 size_t tls_image = 0;
1843 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1844 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1845 app.phnum = aux[AT_PHNUM];
1846 app.phentsize = aux[AT_PHENT];
1847 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1848 if (phdr->p_type == PT_PHDR)
1849 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1850 else if (phdr->p_type == PT_INTERP)
1851 interp_off = (size_t)phdr->p_vaddr;
1852 else if (phdr->p_type == PT_TLS) {
1853 tls_image = phdr->p_vaddr;
1854 app.tls.len = phdr->p_filesz;
1855 app.tls.size = phdr->p_memsz;
1856 app.tls.align = phdr->p_align;
1857 }
1858 }
1859 if (DL_FDPIC) app.loadmap = app_loadmap;
1860 if (app.tls.size) app.tls.image = laddr(&app, tls_image);
1861 if (interp_off) ldso.name = laddr(&app, interp_off);
1862 if ((aux[0] & (1UL<<AT_EXECFN))
1863 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1864 app.name = (char *)aux[AT_EXECFN];
1865 else
1866 app.name = argv[0];
1867 kernel_mapped_dso(&app);
1868 } else {
1869 int fd;
1870 char *ldname = argv[0];
1871 size_t l = strlen(ldname);
1872 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1873 argv++;
1874 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1875 char *opt = argv[0]+2;
1876 *argv++ = (void *)-1;
1877 if (!*opt) {
1878 break;
1879 } else if (!memcmp(opt, "list", 5)) {
1880 ldd_mode = 1;
1881 } else if (!memcmp(opt, "library-path", 12)) {
1882 if (opt[12]=='=') env_path = opt+13;
1883 else if (opt[12]) *argv = 0;
1884 else if (*argv) env_path = *argv++;
1885 } else if (!memcmp(opt, "preload", 7)) {
1886 if (opt[7]=='=') env_preload = opt+8;
1887 else if (opt[7]) *argv = 0;
1888 else if (*argv) env_preload = *argv++;
1889 } else if (!memcmp(opt, "argv0", 5)) {
1890 if (opt[5]=='=') replace_argv0 = opt+6;
1891 else if (opt[5]) *argv = 0;
1892 else if (*argv) replace_argv0 = *argv++;
1893 } else {
1894 argv[0] = 0;
1895 }
1896 }
1897 argv[-1] = (void *)(argc - (argv-argv_orig));
1898 if (!argv[0]) {
1899 dprintf(2, "musl libc (" LDSO_ARCH ")\n"
1900 "Version %s\n"
1901 "Dynamic Program Loader\n"
1902 "Usage: %s [options] [--] pathname%s\n",
1903 __libc_version, ldname,
1904 ldd_mode ? "" : " [args]");
1905 _exit(1);
1906 }
1907 fd = open(argv[0], O_RDONLY);
1908 if (fd < 0) {
1909 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1910 _exit(1);
1911 }
1912 Ehdr *ehdr = map_library(fd, &app);
1913 if (!ehdr) {
1914 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1915 _exit(1);
1916 }
1917 close(fd);
1918 ldso.name = ldname;
1919 app.name = argv[0];
1920 aux[AT_ENTRY] = (size_t)laddr(&app, ehdr->e_entry);
1921 /* Find the name that would have been used for the dynamic
1922 * linker had ldd not taken its place. */
1923 if (ldd_mode) {
1924 for (i=0; i<app.phnum; i++) {
1925 if (app.phdr[i].p_type == PT_INTERP)
1926 ldso.name = laddr(&app, app.phdr[i].p_vaddr);
1927 }
1928 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1929 }
1930 }
1931 if (app.tls.size) {
1932 libc.tls_head = tls_tail = &app.tls;
1933 app.tls_id = tls_cnt = 1;
1934 #ifdef TLS_ABOVE_TP
1935 app.tls.offset = GAP_ABOVE_TP;
1936 app.tls.offset += (-GAP_ABOVE_TP + (uintptr_t)app.tls.image)
1937 & (app.tls.align-1);
1938 tls_offset = app.tls.offset + app.tls.size;
1939 #else
1940 tls_offset = app.tls.offset = app.tls.size
1941 + ( -((uintptr_t)app.tls.image + app.tls.size)
1942 & (app.tls.align-1) );
1943 #endif
1944 tls_align = MAXP2(tls_align, app.tls.align);
1945 }
1946 decode_dyn(&app);
1947 if (DL_FDPIC) {
1948 makefuncdescs(&app);
1949 if (!app.loadmap) {
1950 app.loadmap = (void *)&app_dummy_loadmap;
1951 app.loadmap->nsegs = 1;
1952 app.loadmap->segs[0].addr = (size_t)app.map;
1953 app.loadmap->segs[0].p_vaddr = (size_t)app.map
1954 - (size_t)app.base;
1955 app.loadmap->segs[0].p_memsz = app.map_len;
1956 }
1957 argv[-3] = (void *)app.loadmap;
1958 }
1959
1960 /* Initial dso chain consists only of the app. */
1961 head = tail = syms_tail = &app;
1962
1963 /* Donate unused parts of app and library mapping to malloc */
1964 reclaim_gaps(&app);
1965 reclaim_gaps(&ldso);
1966
1967 /* Load preload/needed libraries, add symbols to global namespace. */
1968 ldso.deps = (struct dso **)no_deps;
1969 if (env_preload) load_preload(env_preload);
1970 load_deps(&app);
1971 for (struct dso *p=head; p; p=p->next)
1972 add_syms(p);
1973
1974 /* Attach to vdso, if provided by the kernel, last so that it does
1975 * not become part of the global namespace. */
1976 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
1977 Ehdr *ehdr = (void *)vdso_base;
1978 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1979 vdso.phnum = ehdr->e_phnum;
1980 vdso.phentsize = ehdr->e_phentsize;
1981 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1982 if (phdr->p_type == PT_DYNAMIC)
1983 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1984 if (phdr->p_type == PT_LOAD)
1985 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1986 }
1987 vdso.name = "";
1988 vdso.shortname = "linux-gate.so.1";
1989 vdso.relocated = 1;
1990 vdso.deps = (struct dso **)no_deps;
1991 decode_dyn(&vdso);
1992 vdso.prev = tail;
1993 tail->next = &vdso;
1994 tail = &vdso;
1995 }
1996
1997 for (i=0; app.dynv[i]; i+=2) {
1998 if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
1999 app.dynv[i+1] = (size_t)&debug;
2000 if (DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG_INDIRECT) {
2001 size_t *ptr = (size_t *) app.dynv[i+1];
2002 *ptr = (size_t)&debug;
2003 }
2004 }
2005
2006 /* This must be done before final relocations, since it calls
2007 * malloc, which may be provided by the application. Calling any
2008 * application code prior to the jump to its entry point is not
2009 * valid in our model and does not work with FDPIC, where there
2010 * are additional relocation-like fixups that only the entry point
2011 * code can see to perform. */
2012 main_ctor_queue = queue_ctors(&app);
2013
2014 /* Initial TLS must also be allocated before final relocations
2015 * might result in calloc being a call to application code. */
2016 update_tls_size();
2017 void *initial_tls = builtin_tls;
2018 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
2019 initial_tls = calloc(libc.tls_size, 1);
2020 if (!initial_tls) {
2021 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
2022 argv[0], libc.tls_size);
2023 _exit(127);
2024 }
2025 }
2026 static_tls_cnt = tls_cnt;
2027
2028 /* The main program must be relocated LAST since it may contain
2029 * copy relocations which depend on libraries' relocations. */
2030 reloc_all(app.next);
2031 reloc_all(&app);
2032
2033 /* Actual copying to new TLS needs to happen after relocations,
2034 * since the TLS images might have contained relocated addresses. */
2035 if (initial_tls != builtin_tls) {
2036 if (__init_tp(__copy_tls(initial_tls)) < 0) {
2037 a_crash();
2038 }
2039 } else {
2040 size_t tmp_tls_size = libc.tls_size;
2041 pthread_t self = __pthread_self();
2042 /* Temporarily set the tls size to the full size of
2043 * builtin_tls so that __copy_tls will use the same layout
2044 * as it did for before. Then check, just to be safe. */
2045 libc.tls_size = sizeof builtin_tls;
2046 if (__copy_tls((void*)builtin_tls) != self) a_crash();
2047 libc.tls_size = tmp_tls_size;
2048 }
2049
2050 if (ldso_fail) _exit(127);
2051 if (ldd_mode) _exit(0);
2052
2053 /* Determine if malloc was interposed by a replacement implementation
2054 * so that calloc and the memalign family can harden against the
2055 * possibility of incomplete replacement. */
2056 if (find_sym(head, "malloc", 1).dso != &ldso)
2057 __malloc_replaced = 1;
2058 if (find_sym(head, "aligned_alloc", 1).dso != &ldso)
2059 __aligned_alloc_replaced = 1;
2060
2061 /* Determine if another DSO is providing the _dl_debug_state symbol
2062 * and forward calls to it. */
2063 struct symdef debug_sym = find_sym(head, "_dl_debug_state", 1);
2064 if (debug_sym.dso != &ldso)
2065 exe_dl_debug_state = (void (*)(void))laddr(debug_sym.dso, debug_sym.sym->st_value);
2066
2067 /* Switch to runtime mode: any further failures in the dynamic
2068 * linker are a reportable failure rather than a fatal startup
2069 * error. */
2070 runtime = 1;
2071
2072 debug.ver = 1;
2073 debug.bp = dl_debug_state;
2074 debug.head = head;
2075 debug.base = ldso.base;
2076 debug.state = RT_CONSISTENT;
2077 _dl_debug_state();
2078
2079 if (replace_argv0) argv[0] = replace_argv0;
2080
2081 errno = 0;
2082
2083 CRTJMP((void *)aux[AT_ENTRY], argv-1);
2084 for(;;);
2085 }
2086
prepare_lazy(struct dso * p)2087 static void prepare_lazy(struct dso *p)
2088 {
2089 size_t dyn[DYN_CNT], n, flags1=0;
2090 decode_vec(p->dynv, dyn, DYN_CNT);
2091 search_vec(p->dynv, &flags1, DT_FLAGS_1);
2092 if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
2093 return;
2094 n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
2095 if (NEED_MIPS_GOT_RELOCS) {
2096 size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
2097 size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
2098 n += i-j;
2099 }
2100 p->lazy = calloc(n, 3*sizeof(size_t));
2101 if (!p->lazy) {
2102 error("Error preparing lazy relocation for %s: %m", p->name);
2103 longjmp(*rtld_fail, 1);
2104 }
2105 p->lazy_next = lazy_head;
2106 lazy_head = p;
2107 }
2108
dlopen(const char * file,int mode)2109 void *dlopen(const char *file, int mode)
2110 {
2111 struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
2112 struct tls_module *orig_tls_tail;
2113 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
2114 size_t i;
2115 int cs;
2116 jmp_buf jb;
2117 struct dso **volatile ctor_queue = 0;
2118
2119 if (!file) return head;
2120
2121 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
2122 pthread_rwlock_wrlock(&lock);
2123 __inhibit_ptc();
2124
2125 debug.state = RT_ADD;
2126 _dl_debug_state();
2127
2128 p = 0;
2129 if (shutting_down) {
2130 error("Cannot dlopen while program is exiting.");
2131 goto end;
2132 }
2133 orig_tls_tail = tls_tail;
2134 orig_tls_cnt = tls_cnt;
2135 orig_tls_offset = tls_offset;
2136 orig_tls_align = tls_align;
2137 orig_lazy_head = lazy_head;
2138 orig_syms_tail = syms_tail;
2139 orig_tail = tail;
2140 noload = mode & RTLD_NOLOAD;
2141
2142 rtld_fail = &jb;
2143 if (setjmp(*rtld_fail)) {
2144 /* Clean up anything new that was (partially) loaded */
2145 revert_syms(orig_syms_tail);
2146 for (p=orig_tail->next; p; p=next) {
2147 next = p->next;
2148 while (p->td_index) {
2149 void *tmp = p->td_index->next;
2150 free(p->td_index);
2151 p->td_index = tmp;
2152 }
2153 free(p->funcdescs);
2154 if (p->rpath != p->rpath_orig)
2155 free(p->rpath);
2156 free(p->deps);
2157 unmap_library(p);
2158 free(p);
2159 }
2160 free(ctor_queue);
2161 ctor_queue = 0;
2162 if (!orig_tls_tail) libc.tls_head = 0;
2163 tls_tail = orig_tls_tail;
2164 if (tls_tail) tls_tail->next = 0;
2165 tls_cnt = orig_tls_cnt;
2166 tls_offset = orig_tls_offset;
2167 tls_align = orig_tls_align;
2168 lazy_head = orig_lazy_head;
2169 tail = orig_tail;
2170 tail->next = 0;
2171 p = 0;
2172 goto end;
2173 } else p = load_library(file, head);
2174
2175 if (!p) {
2176 error(noload ?
2177 "Library %s is not already loaded" :
2178 "Error loading shared library %s: %m",
2179 file);
2180 goto end;
2181 }
2182
2183 /* First load handling */
2184 load_deps(p);
2185 extend_bfs_deps(p);
2186 pthread_mutex_lock(&init_fini_lock);
2187 int constructed = p->constructed;
2188 pthread_mutex_unlock(&init_fini_lock);
2189 if (!constructed) ctor_queue = queue_ctors(p);
2190 if (!p->relocated && (mode & RTLD_LAZY)) {
2191 prepare_lazy(p);
2192 for (i=0; p->deps[i]; i++)
2193 if (!p->deps[i]->relocated)
2194 prepare_lazy(p->deps[i]);
2195 }
2196 if (!p->relocated || (mode & RTLD_GLOBAL)) {
2197 /* Make new symbols global, at least temporarily, so we can do
2198 * relocations. If not RTLD_GLOBAL, this is reverted below. */
2199 add_syms(p);
2200 for (i=0; p->deps[i]; i++)
2201 add_syms(p->deps[i]);
2202 }
2203 if (!p->relocated) {
2204 reloc_all(p);
2205 }
2206
2207 /* If RTLD_GLOBAL was not specified, undo any new additions
2208 * to the global symbol table. This is a nop if the library was
2209 * previously loaded and already global. */
2210 if (!(mode & RTLD_GLOBAL))
2211 revert_syms(orig_syms_tail);
2212
2213 /* Processing of deferred lazy relocations must not happen until
2214 * the new libraries are committed; otherwise we could end up with
2215 * relocations resolved to symbol definitions that get removed. */
2216 redo_lazy_relocs();
2217
2218 update_tls_size();
2219 if (tls_cnt != orig_tls_cnt)
2220 install_new_tls();
2221 orig_tail = tail;
2222 end:
2223 debug.state = RT_CONSISTENT;
2224 _dl_debug_state();
2225 __release_ptc();
2226 if (p) gencnt++;
2227 pthread_rwlock_unlock(&lock);
2228 if (ctor_queue) {
2229 do_init_fini(ctor_queue);
2230 free(ctor_queue);
2231 }
2232 pthread_setcancelstate(cs, 0);
2233 return p;
2234 }
2235
__dl_invalid_handle(void * h)2236 hidden int __dl_invalid_handle(void *h)
2237 {
2238 struct dso *p;
2239 for (p=head; p; p=p->next) if (h==p) return 0;
2240 error("Invalid library handle %p", (void *)h);
2241 return 1;
2242 }
2243
addr2dso(size_t a)2244 static void *addr2dso(size_t a)
2245 {
2246 struct dso *p;
2247 size_t i;
2248 if (DL_FDPIC) for (p=head; p; p=p->next) {
2249 i = count_syms(p);
2250 if (a-(size_t)p->funcdescs < i*sizeof(*p->funcdescs))
2251 return p;
2252 }
2253 for (p=head; p; p=p->next) {
2254 if (DL_FDPIC && p->loadmap) {
2255 for (i=0; i<p->loadmap->nsegs; i++) {
2256 if (a-p->loadmap->segs[i].p_vaddr
2257 < p->loadmap->segs[i].p_memsz)
2258 return p;
2259 }
2260 } else {
2261 Phdr *ph = p->phdr;
2262 size_t phcnt = p->phnum;
2263 size_t entsz = p->phentsize;
2264 size_t base = (size_t)p->base;
2265 for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
2266 if (ph->p_type != PT_LOAD) continue;
2267 if (a-base-ph->p_vaddr < ph->p_memsz)
2268 return p;
2269 }
2270 if (a-(size_t)p->map < p->map_len)
2271 return 0;
2272 }
2273 }
2274 return 0;
2275 }
2276
do_dlsym(struct dso * p,const char * s,void * ra)2277 static void *do_dlsym(struct dso *p, const char *s, void *ra)
2278 {
2279 int use_deps = 0;
2280 if (p == head || p == RTLD_DEFAULT) {
2281 p = head;
2282 } else if (p == RTLD_NEXT) {
2283 p = addr2dso((size_t)ra);
2284 if (!p) p=head;
2285 p = p->next;
2286 } else if (__dl_invalid_handle(p)) {
2287 return 0;
2288 } else
2289 use_deps = 1;
2290 struct symdef def = find_sym2(p, s, 0, use_deps);
2291 if (!def.sym) {
2292 error("Symbol not found: %s", s);
2293 return 0;
2294 }
2295 if ((def.sym->st_info&0xf) == STT_TLS)
2296 return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
2297 if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
2298 return def.dso->funcdescs + (def.sym - def.dso->syms);
2299 return laddr(def.dso, def.sym->st_value);
2300 }
2301
dladdr(const void * addr_arg,Dl_info * info)2302 int dladdr(const void *addr_arg, Dl_info *info)
2303 {
2304 size_t addr = (size_t)addr_arg;
2305 struct dso *p;
2306 Sym *sym, *bestsym;
2307 uint32_t nsym;
2308 char *strings;
2309 size_t best = 0;
2310 size_t besterr = -1;
2311
2312 pthread_rwlock_rdlock(&lock);
2313 p = addr2dso(addr);
2314 pthread_rwlock_unlock(&lock);
2315
2316 if (!p) return 0;
2317
2318 sym = p->syms;
2319 strings = p->strings;
2320 nsym = count_syms(p);
2321
2322 if (DL_FDPIC) {
2323 size_t idx = (addr-(size_t)p->funcdescs)
2324 / sizeof(*p->funcdescs);
2325 if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
2326 best = (size_t)(p->funcdescs + idx);
2327 bestsym = sym + idx;
2328 besterr = 0;
2329 }
2330 }
2331
2332 if (!best) for (; nsym; nsym--, sym++) {
2333 if (sym->st_value
2334 && (1<<(sym->st_info&0xf) & OK_TYPES)
2335 && (1<<(sym->st_info>>4) & OK_BINDS)) {
2336 size_t symaddr = (size_t)laddr(p, sym->st_value);
2337 if (symaddr > addr || symaddr <= best)
2338 continue;
2339 best = symaddr;
2340 bestsym = sym;
2341 besterr = addr - symaddr;
2342 if (addr == symaddr)
2343 break;
2344 }
2345 }
2346
2347 if (best && besterr > bestsym->st_size-1) {
2348 best = 0;
2349 bestsym = 0;
2350 }
2351
2352 info->dli_fname = p->name;
2353 info->dli_fbase = p->map;
2354
2355 if (!best) {
2356 info->dli_sname = 0;
2357 info->dli_saddr = 0;
2358 return 1;
2359 }
2360
2361 if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
2362 best = (size_t)(p->funcdescs + (bestsym - p->syms));
2363 info->dli_sname = strings + bestsym->st_name;
2364 info->dli_saddr = (void *)best;
2365
2366 return 1;
2367 }
2368
__dlsym(void * restrict p,const char * restrict s,void * restrict ra)2369 hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
2370 {
2371 void *res;
2372 pthread_rwlock_rdlock(&lock);
2373 res = do_dlsym(p, s, ra);
2374 pthread_rwlock_unlock(&lock);
2375 return res;
2376 }
2377
__dlsym_redir_time64(void * restrict p,const char * restrict s,void * restrict ra)2378 hidden void *__dlsym_redir_time64(void *restrict p, const char *restrict s, void *restrict ra)
2379 {
2380 #if _REDIR_TIME64
2381 const char *suffix, *suffix2 = "";
2382 char redir[36];
2383
2384 /* Map the symbol name to a time64 version of itself according to the
2385 * pattern used for naming the redirected time64 symbols. */
2386 size_t l = strnlen(s, sizeof redir);
2387 if (l<4 || l==sizeof redir) goto no_redir;
2388 if (s[l-2]=='_' && s[l-1]=='r') {
2389 l -= 2;
2390 suffix2 = s+l;
2391 }
2392 if (l<4) goto no_redir;
2393 if (!strcmp(s+l-4, "time")) suffix = "64";
2394 else suffix = "_time64";
2395
2396 /* Use the presence of the remapped symbol name in libc to determine
2397 * whether it's one that requires time64 redirection; replace if so. */
2398 snprintf(redir, sizeof redir, "__%.*s%s%s", (int)l, s, suffix, suffix2);
2399 if (find_sym(&ldso, redir, 1).sym) s = redir;
2400 no_redir:
2401 #endif
2402 return __dlsym(p, s, ra);
2403 }
2404
dl_iterate_phdr(int (* callback)(struct dl_phdr_info * info,size_t size,void * data),void * data)2405 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
2406 {
2407 struct dso *current;
2408 struct dl_phdr_info info;
2409 int ret = 0;
2410 for(current = head; current;) {
2411 info.dlpi_addr = (uintptr_t)current->base;
2412 info.dlpi_name = current->name;
2413 info.dlpi_phdr = current->phdr;
2414 info.dlpi_phnum = current->phnum;
2415 info.dlpi_adds = gencnt;
2416 info.dlpi_subs = 0;
2417 info.dlpi_tls_modid = current->tls_id;
2418 info.dlpi_tls_data = !current->tls_id ? 0 :
2419 __tls_get_addr((tls_mod_off_t[]){current->tls_id,0});
2420
2421 ret = (callback)(&info, sizeof (info), data);
2422
2423 if (ret != 0) break;
2424
2425 pthread_rwlock_rdlock(&lock);
2426 current = current->next;
2427 pthread_rwlock_unlock(&lock);
2428 }
2429 return ret;
2430 }
2431
error_impl(const char * fmt,...)2432 static void error_impl(const char *fmt, ...)
2433 {
2434 va_list ap;
2435 va_start(ap, fmt);
2436 if (!runtime) {
2437 vdprintf(2, fmt, ap);
2438 dprintf(2, "\n");
2439 ldso_fail = 1;
2440 va_end(ap);
2441 return;
2442 }
2443 __dl_vseterr(fmt, ap);
2444 va_end(ap);
2445 }
2446
error_noop(const char * fmt,...)2447 static void error_noop(const char *fmt, ...)
2448 {
2449 }
2450