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fix local-dynamic model TLS on mips and powerpc
[musl.git] / src / ldso / dynlink.c
blobd2a72492e7212b45b4f3090c40f55a52728c780a
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
24 static void error(const char *, ...);
25
26 #ifdef SHARED
27
28 #define MAXP2(a,b) (-(-(a)&-(b)))
29 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
30
31 struct debug {
32 int ver;
33 void *head;
34 void (*bp)(void);
35 int state;
36 void *base;
37 };
38
39 struct td_index {
40 size_t args[2];
41 struct td_index *next;
42 };
43
44 struct dso {
45 unsigned char *base;
46 char *name;
47 size_t *dynv;
48 struct dso *next, *prev;
49
50 Phdr *phdr;
51 int phnum;
52 size_t phentsize;
53 int refcnt;
54 Sym *syms;
55 uint32_t *hashtab;
56 uint32_t *ghashtab;
57 int16_t *versym;
58 char *strings;
59 unsigned char *map;
60 size_t map_len;
61 dev_t dev;
62 ino_t ino;
63 signed char global;
64 char relocated;
65 char constructed;
66 char kernel_mapped;
67 struct dso **deps, *needed_by;
68 char *rpath_orig, *rpath;
69 void *tls_image;
70 size_t tls_len, tls_size, tls_align, tls_id, tls_offset;
71 size_t relro_start, relro_end;
72 void **new_dtv;
73 unsigned char *new_tls;
74 volatile int new_dtv_idx, new_tls_idx;
75 struct td_index *td_index;
76 struct dso *fini_next;
77 char *shortname;
78 char buf[];
79 };
80
81 struct symdef {
82 Sym *sym;
83 struct dso *dso;
84 };
85
86 int __init_tp(void *);
87 void __init_libc(char **, char *);
88
89 const char *__libc_get_version(void);
90
91 static struct builtin_tls {
92 char c;
93 struct pthread pt;
94 void *space[16];
95 } builtin_tls[1];
96 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
97
98 #define ADDEND_LIMIT 4096
99 static size_t *saved_addends, *apply_addends_to;
100
101 static struct dso ldso;
102 static struct dso *head, *tail, *fini_head;
103 static char *env_path, *sys_path;
104 static unsigned long long gencnt;
105 static int runtime;
106 static int ldd_mode;
107 static int ldso_fail;
108 static int noload;
109 static jmp_buf *rtld_fail;
110 static pthread_rwlock_t lock;
111 static struct debug debug;
112 static size_t tls_cnt, tls_offset, tls_align = MIN_TLS_ALIGN;
113 static size_t static_tls_cnt;
114 static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
115
116 struct debug *_dl_debug_addr = &debug;
117
118 static int dl_strcmp(const char *l, const char *r)
119 {
120 for (; *l==*r && *l; l++, r++);
121 return *(unsigned char *)l - *(unsigned char *)r;
122 }
123 #define strcmp(l,r) dl_strcmp(l,r)
124
125 static void decode_vec(size_t *v, size_t *a, size_t cnt)
126 {
127 size_t i;
128 for (i=0; i<cnt; i++) a[i] = 0;
129 for (; v[0]; v+=2) if (v[0]-1<cnt-1) {
130 a[0] |= 1UL<<v[0];
131 a[v[0]] = v[1];
132 }
133 }
134
135 static int search_vec(size_t *v, size_t *r, size_t key)
136 {
137 for (; v[0]!=key; v+=2)
138 if (!v[0]) return 0;
139 *r = v[1];
140 return 1;
141 }
142
143 static uint32_t sysv_hash(const char *s0)
144 {
145 const unsigned char *s = (void *)s0;
146 uint_fast32_t h = 0;
147 while (*s) {
148 h = 16*h + *s++;
149 h ^= h>>24 & 0xf0;
150 }
151 return h & 0xfffffff;
152 }
153
154 static uint32_t gnu_hash(const char *s0)
155 {
156 const unsigned char *s = (void *)s0;
157 uint_fast32_t h = 5381;
158 for (; *s; s++)
159 h = h*33 + *s;
160 return h;
161 }
162
163 static Sym *sysv_lookup(const char *s, uint32_t h, struct dso *dso)
164 {
165 size_t i;
166 Sym *syms = dso->syms;
167 uint32_t *hashtab = dso->hashtab;
168 char *strings = dso->strings;
169 for (i=hashtab[2+h%hashtab[0]]; i; i=hashtab[2+hashtab[0]+i]) {
170 if ((!dso->versym || dso->versym[i] >= 0)
171 && (!strcmp(s, strings+syms[i].st_name)))
172 return syms+i;
173 }
174 return 0;
175 }
176
177 static Sym *gnu_lookup(const char *s, uint32_t h1, struct dso *dso)
178 {
179 Sym *syms = dso->syms;
180 char *strings = dso->strings;
181 uint32_t *hashtab = dso->ghashtab;
182 uint32_t nbuckets = hashtab[0];
183 uint32_t *buckets = hashtab + 4 + hashtab[2]*(sizeof(size_t)/4);
184 uint32_t h2;
185 uint32_t *hashval;
186 uint32_t i = buckets[h1 % nbuckets];
187
188 if (!i) return 0;
189
190 hashval = buckets + nbuckets + (i - hashtab[1]);
191
192 for (h1 |= 1; ; i++) {
193 h2 = *hashval++;
194 if ((!dso->versym || dso->versym[i] >= 0)
195 && (h1 == (h2|1)) && !strcmp(s, strings + syms[i].st_name))
196 return syms+i;
197 if (h2 & 1) break;
198 }
199
200 return 0;
201 }
202
203 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
204 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
205
206 #ifndef ARCH_SYM_REJECT_UND
207 #define ARCH_SYM_REJECT_UND(s) 0
208 #endif
209
210 static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
211 {
212 uint32_t h = 0, gh = 0;
213 struct symdef def = {0};
214 for (; dso; dso=dso->next) {
215 Sym *sym;
216 if (!dso->global) continue;
217 if (dso->ghashtab) {
218 if (!gh) gh = gnu_hash(s);
219 sym = gnu_lookup(s, gh, dso);
220 } else {
221 if (!h) h = sysv_hash(s);
222 sym = sysv_lookup(s, h, dso);
223 }
224 if (!sym) continue;
225 if (!sym->st_shndx)
226 if (need_def || (sym->st_info&0xf) == STT_TLS
227 || ARCH_SYM_REJECT_UND(sym))
228 continue;
229 if (!sym->st_value)
230 if ((sym->st_info&0xf) != STT_TLS)
231 continue;
232 if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
233 if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
234
235 if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
236 def.sym = sym;
237 def.dso = dso;
238 if (sym->st_info>>4 == STB_GLOBAL) break;
239 }
240 return def;
241 }
242
243 __attribute__((__visibility__("hidden")))
244 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
245
246 static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
247 {
248 unsigned char *base = dso->base;
249 Sym *syms = dso->syms;
250 char *strings = dso->strings;
251 Sym *sym;
252 const char *name;
253 void *ctx;
254 int type;
255 int sym_index;
256 struct symdef def;
257 size_t *reloc_addr;
258 size_t sym_val;
259 size_t tls_val;
260 size_t addend;
261 int skip_relative = 0, reuse_addends = 0, save_slot = 0;
262
263 if (dso == &ldso) {
264 /* Only ldso's REL table needs addend saving/reuse. */
265 if (rel == apply_addends_to)
266 reuse_addends = 1;
267 skip_relative = 1;
268 }
269
270 for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
271 if (skip_relative && IS_RELATIVE(rel[1])) continue;
272 type = R_TYPE(rel[1]);
273 if (type == REL_NONE) continue;
274 sym_index = R_SYM(rel[1]);
275 reloc_addr = (void *)(base + rel[0]);
276 if (sym_index) {
277 sym = syms + sym_index;
278 name = strings + sym->st_name;
279 ctx = type==REL_COPY ? head->next : head;
280 def = find_sym(ctx, name, type==REL_PLT);
281 if (!def.sym && (sym->st_shndx != SHN_UNDEF
282 || sym->st_info>>4 != STB_WEAK)) {
283 error("Error relocating %s: %s: symbol not found",
284 dso->name, name);
285 if (runtime) longjmp(*rtld_fail, 1);
286 continue;
287 }
288 } else {
289 sym = 0;
290 def.sym = 0;
291 def.dso = dso;
292 }
293
294 if (stride > 2) {
295 addend = rel[2];
296 } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
297 addend = 0;
298 } else if (reuse_addends) {
299 /* Save original addend in stage 2 where the dso
300 * chain consists of just ldso; otherwise read back
301 * saved addend since the inline one was clobbered. */
302 if (head==&ldso)
303 saved_addends[save_slot] = *reloc_addr;
304 addend = saved_addends[save_slot++];
305 } else {
306 addend = *reloc_addr;
307 }
308
309 sym_val = def.sym ? (size_t)def.dso->base+def.sym->st_value : 0;
310 tls_val = def.sym ? def.sym->st_value : 0;
311
312 switch(type) {
313 case REL_NONE:
314 break;
315 case REL_OFFSET:
316 addend -= (size_t)reloc_addr;
317 case REL_SYMBOLIC:
318 case REL_GOT:
319 case REL_PLT:
320 *reloc_addr = sym_val + addend;
321 break;
322 case REL_RELATIVE:
323 *reloc_addr = (size_t)base + addend;
324 break;
325 case REL_SYM_OR_REL:
326 if (sym) *reloc_addr = sym_val + addend;
327 else *reloc_addr = (size_t)base + addend;
328 break;
329 case REL_COPY:
330 memcpy(reloc_addr, (void *)sym_val, sym->st_size);
331 break;
332 case REL_OFFSET32:
333 *(uint32_t *)reloc_addr = sym_val + addend
334 - (size_t)reloc_addr;
335 break;
336 case REL_DTPMOD:
337 *reloc_addr = def.dso->tls_id;
338 break;
339 case REL_DTPOFF:
340 *reloc_addr = tls_val + addend - DTP_OFFSET;
341 break;
342 #ifdef TLS_ABOVE_TP
343 case REL_TPOFF:
344 *reloc_addr = tls_val + def.dso->tls_offset + TPOFF_K + addend;
345 break;
346 #else
347 case REL_TPOFF:
348 *reloc_addr = tls_val - def.dso->tls_offset + addend;
349 break;
350 case REL_TPOFF_NEG:
351 *reloc_addr = def.dso->tls_offset - tls_val + addend;
352 break;
353 #endif
354 case REL_TLSDESC:
355 if (stride<3) addend = reloc_addr[1];
356 if (runtime && def.dso->tls_id >= static_tls_cnt) {
357 struct td_index *new = malloc(sizeof *new);
358 if (!new) {
359 error(
360 "Error relocating %s: cannot allocate TLSDESC for %s",
361 dso->name, sym ? name : "(local)" );
362 longjmp(*rtld_fail, 1);
363 }
364 new->next = dso->td_index;
365 dso->td_index = new;
366 new->args[0] = def.dso->tls_id;
367 new->args[1] = tls_val + addend;
368 reloc_addr[0] = (size_t)__tlsdesc_dynamic;
369 reloc_addr[1] = (size_t)new;
370 } else {
371 reloc_addr[0] = (size_t)__tlsdesc_static;
372 #ifdef TLS_ABOVE_TP
373 reloc_addr[1] = tls_val + def.dso->tls_offset
374 + TPOFF_K + addend;
375 #else
376 reloc_addr[1] = tls_val - def.dso->tls_offset
377 + addend;
378 #endif
379 }
380 break;
381 default:
382 error("Error relocating %s: unsupported relocation type %d",
383 dso->name, type);
384 if (runtime) longjmp(*rtld_fail, 1);
385 continue;
386 }
387 }
388 }
389
390 /* A huge hack: to make up for the wastefulness of shared libraries
391 * needing at least a page of dirty memory even if they have no global
392 * data, we reclaim the gaps at the beginning and end of writable maps
393 * and "donate" them to the heap by setting up minimal malloc
394 * structures and then freeing them. */
395
396 static void reclaim(struct dso *dso, size_t start, size_t end)
397 {
398 size_t *a, *z;
399 if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
400 if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
401 start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
402 end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
403 if (start>end || end-start < 4*sizeof(size_t)) return;
404 a = (size_t *)(dso->base + start);
405 z = (size_t *)(dso->base + end);
406 a[-2] = 1;
407 a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
408 z[1] = 1;
409 free(a);
410 }
411
412 static void reclaim_gaps(struct dso *dso)
413 {
414 Phdr *ph = dso->phdr;
415 size_t phcnt = dso->phnum;
416
417 for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
418 if (ph->p_type!=PT_LOAD) continue;
419 if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
420 reclaim(dso, ph->p_vaddr & -PAGE_SIZE, ph->p_vaddr);
421 reclaim(dso, ph->p_vaddr+ph->p_memsz,
422 ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE);
423 }
424 }
425
426 static void *mmap_fixed(void *p, size_t n, int prot, int flags, int fd, off_t off)
427 {
428 char *q = mmap(p, n, prot, flags, fd, off);
429 if (q != MAP_FAILED || errno != EINVAL) return q;
430 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
431 if (flags & MAP_ANONYMOUS) {
432 memset(p, 0, n);
433 return p;
434 }
435 ssize_t r;
436 if (lseek(fd, off, SEEK_SET) < 0) return MAP_FAILED;
437 for (q=p; n; q+=r, off+=r, n-=r) {
438 r = read(fd, q, n);
439 if (r < 0 && errno != EINTR) return MAP_FAILED;
440 if (!r) {
441 memset(q, 0, n);
442 break;
443 }
444 }
445 return p;
446 }
447
448 static void *map_library(int fd, struct dso *dso)
449 {
450 Ehdr buf[(896+sizeof(Ehdr))/sizeof(Ehdr)];
451 void *allocated_buf=0;
452 size_t phsize;
453 size_t addr_min=SIZE_MAX, addr_max=0, map_len;
454 size_t this_min, this_max;
455 off_t off_start;
456 Ehdr *eh;
457 Phdr *ph, *ph0;
458 unsigned prot;
459 unsigned char *map=MAP_FAILED, *base;
460 size_t dyn=0;
461 size_t tls_image=0;
462 size_t i;
463
464 ssize_t l = read(fd, buf, sizeof buf);
465 eh = buf;
466 if (l<0) return 0;
467 if (l<sizeof *eh || (eh->e_type != ET_DYN && eh->e_type != ET_EXEC))
468 goto noexec;
469 phsize = eh->e_phentsize * eh->e_phnum;
470 if (phsize > sizeof buf - sizeof *eh) {
471 allocated_buf = malloc(phsize);
472 if (!allocated_buf) return 0;
473 l = pread(fd, allocated_buf, phsize, eh->e_phoff);
474 if (l < 0) goto error;
475 if (l != phsize) goto noexec;
476 ph = ph0 = allocated_buf;
477 } else if (eh->e_phoff + phsize > l) {
478 l = pread(fd, buf+1, phsize, eh->e_phoff);
479 if (l < 0) goto error;
480 if (l != phsize) goto noexec;
481 ph = ph0 = (void *)(buf + 1);
482 } else {
483 ph = ph0 = (void *)((char *)buf + eh->e_phoff);
484 }
485 for (i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
486 if (ph->p_type == PT_DYNAMIC) {
487 dyn = ph->p_vaddr;
488 } else if (ph->p_type == PT_TLS) {
489 tls_image = ph->p_vaddr;
490 dso->tls_align = ph->p_align;
491 dso->tls_len = ph->p_filesz;
492 dso->tls_size = ph->p_memsz;
493 } else if (ph->p_type == PT_GNU_RELRO) {
494 dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
495 dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
496 }
497 if (ph->p_type != PT_LOAD) continue;
498 if (ph->p_vaddr < addr_min) {
499 addr_min = ph->p_vaddr;
500 off_start = ph->p_offset;
501 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
502 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
503 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
504 }
505 if (ph->p_vaddr+ph->p_memsz > addr_max) {
506 addr_max = ph->p_vaddr+ph->p_memsz;
507 }
508 }
509 if (!dyn) goto noexec;
510 addr_max += PAGE_SIZE-1;
511 addr_max &= -PAGE_SIZE;
512 addr_min &= -PAGE_SIZE;
513 off_start &= -PAGE_SIZE;
514 map_len = addr_max - addr_min + off_start;
515 /* The first time, we map too much, possibly even more than
516 * the length of the file. This is okay because we will not
517 * use the invalid part; we just need to reserve the right
518 * amount of virtual address space to map over later. */
519 map = mmap((void *)addr_min, map_len, prot, MAP_PRIVATE, fd, off_start);
520 if (map==MAP_FAILED) goto error;
521 /* If the loaded file is not relocatable and the requested address is
522 * not available, then the load operation must fail. */
523 if (eh->e_type != ET_DYN && addr_min && map!=(void *)addr_min) {
524 errno = EBUSY;
525 goto error;
526 }
527 base = map - addr_min;
528 dso->phdr = 0;
529 dso->phnum = 0;
530 for (ph=ph0, i=eh->e_phnum; i; i--, ph=(void *)((char *)ph+eh->e_phentsize)) {
531 if (ph->p_type != PT_LOAD) continue;
532 /* Check if the programs headers are in this load segment, and
533 * if so, record the address for use by dl_iterate_phdr. */
534 if (!dso->phdr && eh->e_phoff >= ph->p_offset
535 && eh->e_phoff+phsize <= ph->p_offset+ph->p_filesz) {
536 dso->phdr = (void *)(base + ph->p_vaddr
537 + (eh->e_phoff-ph->p_offset));
538 dso->phnum = eh->e_phnum;
539 dso->phentsize = eh->e_phentsize;
540 }
541 /* Reuse the existing mapping for the lowest-address LOAD */
542 if ((ph->p_vaddr & -PAGE_SIZE) == addr_min) continue;
543 this_min = ph->p_vaddr & -PAGE_SIZE;
544 this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
545 off_start = ph->p_offset & -PAGE_SIZE;
546 prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
547 ((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
548 ((ph->p_flags&PF_X) ? PROT_EXEC : 0));
549 if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
550 goto error;
551 if (ph->p_memsz > ph->p_filesz) {
552 size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
553 size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
554 memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
555 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)
556 goto error;
557 }
558 }
559 for (i=0; ((size_t *)(base+dyn))[i]; i+=2)
560 if (((size_t *)(base+dyn))[i]==DT_TEXTREL) {
561 if (mprotect(map, map_len, PROT_READ|PROT_WRITE|PROT_EXEC)
562 && errno != ENOSYS)
563 goto error;
564 break;
565 }
566 dso->map = map;
567 dso->map_len = map_len;
568 dso->base = base;
569 dso->dynv = (void *)(base+dyn);
570 if (dso->tls_size) dso->tls_image = (void *)(base+tls_image);
571 if (!runtime) reclaim_gaps(dso);
572 free(allocated_buf);
573 return map;
574 noexec:
575 errno = ENOEXEC;
576 error:
577 if (map!=MAP_FAILED) munmap(map, map_len);
578 free(allocated_buf);
579 return 0;
580 }
581
582 static int path_open(const char *name, const char *s, char *buf, size_t buf_size)
583 {
584 size_t l;
585 int fd;
586 for (;;) {
587 s += strspn(s, ":\n");
588 l = strcspn(s, ":\n");
589 if (l-1 >= INT_MAX) return -1;
590 if (snprintf(buf, buf_size, "%.*s/%s", (int)l, s, name) < buf_size) {
591 if ((fd = open(buf, O_RDONLY|O_CLOEXEC))>=0) return fd;
592 switch (errno) {
593 case ENOENT:
594 case ENOTDIR:
595 case EACCES:
596 case ENAMETOOLONG:
597 break;
598 default:
599 /* Any negative value but -1 will inhibit
600 * futher path search. */
601 return -2;
602 }
603 }
604 s += l;
605 }
606 }
607
608 static int fixup_rpath(struct dso *p, char *buf, size_t buf_size)
609 {
610 size_t n, l;
611 const char *s, *t, *origin;
612 char *d;
613 if (p->rpath || !p->rpath_orig) return 0;
614 if (!strchr(p->rpath_orig, '$')) {
615 p->rpath = p->rpath_orig;
616 return 0;
617 }
618 n = 0;
619 s = p->rpath_orig;
620 while ((t=strchr(s, '$'))) {
621 if (strncmp(t, "$ORIGIN", 7) && strncmp(t, "${ORIGIN}", 9))
622 return 0;
623 s = t+1;
624 n++;
625 }
626 if (n > SSIZE_MAX/PATH_MAX) return 0;
627
628 if (p->kernel_mapped) {
629 /* $ORIGIN searches cannot be performed for the main program
630 * when it is suid/sgid/AT_SECURE. This is because the
631 * pathname is under the control of the caller of execve.
632 * For libraries, however, $ORIGIN can be processed safely
633 * since the library's pathname came from a trusted source
634 * (either system paths or a call to dlopen). */
635 if (libc.secure)
636 return 0;
637 l = readlink("/proc/self/exe", buf, buf_size);
638 if (l == -1) switch (errno) {
639 case ENOENT:
640 case ENOTDIR:
641 case EACCES:
642 break;
643 default:
644 return -1;
645 }
646 if (l >= buf_size)
647 return 0;
648 buf[l] = 0;
649 origin = buf;
650 } else {
651 origin = p->name;
652 }
653 t = strrchr(origin, '/');
654 l = t ? t-origin : 0;
655 p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
656 if (!p->rpath) return -1;
657
658 d = p->rpath;
659 s = p->rpath_orig;
660 while ((t=strchr(s, '$'))) {
661 memcpy(d, s, t-s);
662 d += t-s;
663 memcpy(d, origin, l);
664 d += l;
665 /* It was determined previously that the '$' is followed
666 * either by "ORIGIN" or "{ORIGIN}". */
667 s = t + 7 + 2*(t[1]=='{');
668 }
669 strcpy(d, s);
670 return 0;
671 }
672
673 static void decode_dyn(struct dso *p)
674 {
675 size_t dyn[DYN_CNT];
676 decode_vec(p->dynv, dyn, DYN_CNT);
677 p->syms = (void *)(p->base + dyn[DT_SYMTAB]);
678 p->strings = (void *)(p->base + dyn[DT_STRTAB]);
679 if (dyn[0]&(1<<DT_HASH))
680 p->hashtab = (void *)(p->base + dyn[DT_HASH]);
681 if (dyn[0]&(1<<DT_RPATH))
682 p->rpath_orig = (void *)(p->strings + dyn[DT_RPATH]);
683 if (dyn[0]&(1<<DT_RUNPATH))
684 p->rpath_orig = (void *)(p->strings + dyn[DT_RUNPATH]);
685 if (search_vec(p->dynv, dyn, DT_GNU_HASH))
686 p->ghashtab = (void *)(p->base + *dyn);
687 if (search_vec(p->dynv, dyn, DT_VERSYM))
688 p->versym = (void *)(p->base + *dyn);
689 }
690
691 static struct dso *load_library(const char *name, struct dso *needed_by)
692 {
693 char buf[2*NAME_MAX+2];
694 const char *pathname;
695 unsigned char *map;
696 struct dso *p, temp_dso = {0};
697 int fd;
698 struct stat st;
699 size_t alloc_size;
700 int n_th = 0;
701 int is_self = 0;
702
703 if (!*name) {
704 errno = EINVAL;
705 return 0;
706 }
707
708 /* Catch and block attempts to reload the implementation itself */
709 if (name[0]=='l' && name[1]=='i' && name[2]=='b') {
710 static const char *rp, reserved[] =
711 "c\0pthread\0rt\0m\0dl\0util\0xnet\0";
712 char *z = strchr(name, '.');
713 if (z) {
714 size_t l = z-name;
715 for (rp=reserved; *rp && strncmp(name+3, rp, l-3); rp+=strlen(rp)+1);
716 if (*rp) {
717 if (ldd_mode) {
718 /* Track which names have been resolved
719 * and only report each one once. */
720 static unsigned reported;
721 unsigned mask = 1U<<(rp-reserved);
722 if (!(reported & mask)) {
723 reported |= mask;
724 dprintf(1, "\t%s => %s (%p)\n",
725 name, ldso.name,
726 ldso.base);
727 }
728 }
729 is_self = 1;
730 }
731 }
732 }
733 if (!strcmp(name, ldso.name)) is_self = 1;
734 if (is_self) {
735 if (!ldso.prev) {
736 tail->next = &ldso;
737 ldso.prev = tail;
738 tail = ldso.next ? ldso.next : &ldso;
739 }
740 return &ldso;
741 }
742 if (strchr(name, '/')) {
743 pathname = name;
744 fd = open(name, O_RDONLY|O_CLOEXEC);
745 } else {
746 /* Search for the name to see if it's already loaded */
747 for (p=head->next; p; p=p->next) {
748 if (p->shortname && !strcmp(p->shortname, name)) {
749 p->refcnt++;
750 return p;
751 }
752 }
753 if (strlen(name) > NAME_MAX) return 0;
754 fd = -1;
755 if (env_path) fd = path_open(name, env_path, buf, sizeof buf);
756 for (p=needed_by; fd == -1 && p; p=p->needed_by) {
757 if (fixup_rpath(p, buf, sizeof buf) < 0)
758 fd = -2; /* Inhibit further search. */
759 if (p->rpath)
760 fd = path_open(name, p->rpath, buf, sizeof buf);
761 }
762 if (fd == -1) {
763 if (!sys_path) {
764 char *prefix = 0;
765 size_t prefix_len;
766 if (ldso.name[0]=='/') {
767 char *s, *t, *z;
768 for (s=t=z=ldso.name; *s; s++)
769 if (*s=='/') z=t, t=s;
770 prefix_len = z-ldso.name;
771 if (prefix_len < PATH_MAX)
772 prefix = ldso.name;
773 }
774 if (!prefix) {
775 prefix = "";
776 prefix_len = 0;
777 }
778 char etc_ldso_path[prefix_len + 1
779 + sizeof "/etc/ld-musl-" LDSO_ARCH ".path"];
780 snprintf(etc_ldso_path, sizeof etc_ldso_path,
781 "%.*s/etc/ld-musl-" LDSO_ARCH ".path",
782 (int)prefix_len, prefix);
783 FILE *f = fopen(etc_ldso_path, "rbe");
784 if (f) {
785 if (getdelim(&sys_path, (size_t[1]){0}, 0, f) <= 0) {
786 free(sys_path);
787 sys_path = "";
788 }
789 fclose(f);
790 } else if (errno != ENOENT) {
791 sys_path = "";
792 }
793 }
794 if (!sys_path) sys_path = "/lib:/usr/local/lib:/usr/lib";
795 fd = path_open(name, sys_path, buf, sizeof buf);
796 }
797 pathname = buf;
798 }
799 if (fd < 0) return 0;
800 if (fstat(fd, &st) < 0) {
801 close(fd);
802 return 0;
803 }
804 for (p=head->next; p; p=p->next) {
805 if (p->dev == st.st_dev && p->ino == st.st_ino) {
806 /* If this library was previously loaded with a
807 * pathname but a search found the same inode,
808 * setup its shortname so it can be found by name. */
809 if (!p->shortname && pathname != name)
810 p->shortname = strrchr(p->name, '/')+1;
811 close(fd);
812 p->refcnt++;
813 return p;
814 }
815 }
816 map = noload ? 0 : map_library(fd, &temp_dso);
817 close(fd);
818 if (!map) return 0;
819
820 /* Allocate storage for the new DSO. When there is TLS, this
821 * storage must include a reservation for all pre-existing
822 * threads to obtain copies of both the new TLS, and an
823 * extended DTV capable of storing an additional slot for
824 * the newly-loaded DSO. */
825 alloc_size = sizeof *p + strlen(pathname) + 1;
826 if (runtime && temp_dso.tls_image) {
827 size_t per_th = temp_dso.tls_size + temp_dso.tls_align
828 + sizeof(void *) * (tls_cnt+3);
829 n_th = libc.threads_minus_1 + 1;
830 if (n_th > SSIZE_MAX / per_th) alloc_size = SIZE_MAX;
831 else alloc_size += n_th * per_th;
832 }
833 p = calloc(1, alloc_size);
834 if (!p) {
835 munmap(map, temp_dso.map_len);
836 return 0;
837 }
838 memcpy(p, &temp_dso, sizeof temp_dso);
839 decode_dyn(p);
840 p->dev = st.st_dev;
841 p->ino = st.st_ino;
842 p->refcnt = 1;
843 p->needed_by = needed_by;
844 p->name = p->buf;
845 strcpy(p->name, pathname);
846 /* Add a shortname only if name arg was not an explicit pathname. */
847 if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
848 if (p->tls_image) {
849 p->tls_id = ++tls_cnt;
850 tls_align = MAXP2(tls_align, p->tls_align);
851 #ifdef TLS_ABOVE_TP
852 p->tls_offset = tls_offset + ( (tls_align-1) &
853 -(tls_offset + (uintptr_t)p->tls_image) );
854 tls_offset += p->tls_size;
855 #else
856 tls_offset += p->tls_size + p->tls_align - 1;
857 tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
858 & (p->tls_align-1);
859 p->tls_offset = tls_offset;
860 #endif
861 p->new_dtv = (void *)(-sizeof(size_t) &
862 (uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
863 p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
864 }
865
866 tail->next = p;
867 p->prev = tail;
868 tail = p;
869
870 if (ldd_mode) dprintf(1, "\t%s => %s (%p)\n", name, pathname, p->base);
871
872 return p;
873 }
874
875 static void load_deps(struct dso *p)
876 {
877 size_t i, ndeps=0;
878 struct dso ***deps = &p->deps, **tmp, *dep;
879 for (; p; p=p->next) {
880 for (i=0; p->dynv[i]; i+=2) {
881 if (p->dynv[i] != DT_NEEDED) continue;
882 dep = load_library(p->strings + p->dynv[i+1], p);
883 if (!dep) {
884 error("Error loading shared library %s: %m (needed by %s)",
885 p->strings + p->dynv[i+1], p->name);
886 if (runtime) longjmp(*rtld_fail, 1);
887 continue;
888 }
889 if (runtime) {
890 tmp = realloc(*deps, sizeof(*tmp)*(ndeps+2));
891 if (!tmp) longjmp(*rtld_fail, 1);
892 tmp[ndeps++] = dep;
893 tmp[ndeps] = 0;
894 *deps = tmp;
895 }
896 }
897 }
898 }
899
900 static void load_preload(char *s)
901 {
902 int tmp;
903 char *z;
904 for (z=s; *z; s=z) {
905 for ( ; *s && (isspace(*s) || *s==':'); s++);
906 for (z=s; *z && !isspace(*z) && *z!=':'; z++);
907 tmp = *z;
908 *z = 0;
909 load_library(s, 0);
910 *z = tmp;
911 }
912 }
913
914 static void make_global(struct dso *p)
915 {
916 for (; p; p=p->next) p->global = 1;
917 }
918
919 static void do_mips_relocs(struct dso *p, size_t *got)
920 {
921 size_t i, j, rel[2];
922 unsigned char *base = p->base;
923 i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
924 if (p==&ldso) {
925 got += i;
926 } else {
927 while (i--) *got++ += (size_t)base;
928 }
929 j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
930 i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
931 Sym *sym = p->syms + j;
932 rel[0] = (unsigned char *)got - base;
933 for (i-=j; i; i--, sym++, rel[0]+=sizeof(size_t)) {
934 rel[1] = sym-p->syms << 8 | R_MIPS_JUMP_SLOT;
935 do_relocs(p, rel, sizeof rel, 2);
936 }
937 }
938
939 static void reloc_all(struct dso *p)
940 {
941 size_t dyn[DYN_CNT];
942 for (; p; p=p->next) {
943 if (p->relocated) continue;
944 decode_vec(p->dynv, dyn, DYN_CNT);
945 if (NEED_MIPS_GOT_RELOCS)
946 do_mips_relocs(p, (void *)(p->base+dyn[DT_PLTGOT]));
947 do_relocs(p, (void *)(p->base+dyn[DT_JMPREL]), dyn[DT_PLTRELSZ],
948 2+(dyn[DT_PLTREL]==DT_RELA));
949 do_relocs(p, (void *)(p->base+dyn[DT_REL]), dyn[DT_RELSZ], 2);
950 do_relocs(p, (void *)(p->base+dyn[DT_RELA]), dyn[DT_RELASZ], 3);
951
952 if (head != &ldso && p->relro_start != p->relro_end &&
953 mprotect(p->base+p->relro_start, p->relro_end-p->relro_start, PROT_READ)
954 && errno != ENOSYS) {
955 error("Error relocating %s: RELRO protection failed: %m",
956 p->name);
957 if (runtime) longjmp(*rtld_fail, 1);
958 }
959
960 p->relocated = 1;
961 }
962 }
963
964 static void kernel_mapped_dso(struct dso *p)
965 {
966 size_t min_addr = -1, max_addr = 0, cnt;
967 Phdr *ph = p->phdr;
968 for (cnt = p->phnum; cnt--; ph = (void *)((char *)ph + p->phentsize)) {
969 if (ph->p_type == PT_DYNAMIC) {
970 p->dynv = (void *)(p->base + ph->p_vaddr);
971 } else if (ph->p_type == PT_GNU_RELRO) {
972 p->relro_start = ph->p_vaddr & -PAGE_SIZE;
973 p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
974 }
975 if (ph->p_type != PT_LOAD) continue;
976 if (ph->p_vaddr < min_addr)
977 min_addr = ph->p_vaddr;
978 if (ph->p_vaddr+ph->p_memsz > max_addr)
979 max_addr = ph->p_vaddr+ph->p_memsz;
980 }
981 min_addr &= -PAGE_SIZE;
982 max_addr = (max_addr + PAGE_SIZE-1) & -PAGE_SIZE;
983 p->map = p->base + min_addr;
984 p->map_len = max_addr - min_addr;
985 p->kernel_mapped = 1;
986 }
987
988 static void do_fini()
989 {
990 struct dso *p;
991 size_t dyn[DYN_CNT];
992 for (p=fini_head; p; p=p->fini_next) {
993 if (!p->constructed) continue;
994 decode_vec(p->dynv, dyn, DYN_CNT);
995 if (dyn[0] & (1<<DT_FINI_ARRAY)) {
996 size_t n = dyn[DT_FINI_ARRAYSZ]/sizeof(size_t);
997 size_t *fn = (size_t *)(p->base + dyn[DT_FINI_ARRAY])+n;
998 while (n--) ((void (*)(void))*--fn)();
999 }
1000 #ifndef NO_LEGACY_INITFINI
1001 if ((dyn[0] & (1<<DT_FINI)) && dyn[DT_FINI])
1002 ((void (*)(void))(p->base + dyn[DT_FINI]))();
1003 #endif
1004 }
1005 }
1006
1007 static void do_init_fini(struct dso *p)
1008 {
1009 size_t dyn[DYN_CNT];
1010 int need_locking = libc.threads_minus_1;
1011 /* Allow recursive calls that arise when a library calls
1012 * dlopen from one of its constructors, but block any
1013 * other threads until all ctors have finished. */
1014 if (need_locking) pthread_mutex_lock(&init_fini_lock);
1015 for (; p; p=p->prev) {
1016 if (p->constructed) continue;
1017 p->constructed = 1;
1018 decode_vec(p->dynv, dyn, DYN_CNT);
1019 if (dyn[0] & ((1<<DT_FINI) | (1<<DT_FINI_ARRAY))) {
1020 p->fini_next = fini_head;
1021 fini_head = p;
1022 }
1023 #ifndef NO_LEGACY_INITFINI
1024 if ((dyn[0] & (1<<DT_INIT)) && dyn[DT_INIT])
1025 ((void (*)(void))(p->base + dyn[DT_INIT]))();
1026 #endif
1027 if (dyn[0] & (1<<DT_INIT_ARRAY)) {
1028 size_t n = dyn[DT_INIT_ARRAYSZ]/sizeof(size_t);
1029 size_t *fn = (void *)(p->base + dyn[DT_INIT_ARRAY]);
1030 while (n--) ((void (*)(void))*fn++)();
1031 }
1032 if (!need_locking && libc.threads_minus_1) {
1033 need_locking = 1;
1034 pthread_mutex_lock(&init_fini_lock);
1035 }
1036 }
1037 if (need_locking) pthread_mutex_unlock(&init_fini_lock);
1038 }
1039
1040 static void dl_debug_state(void)
1041 {
1042 }
1043
1044 weak_alias(dl_debug_state, _dl_debug_state);
1045
1046 void __reset_tls()
1047 {
1048 pthread_t self = __pthread_self();
1049 struct dso *p;
1050 for (p=head; p; p=p->next) {
1051 if (!p->tls_id || !self->dtv[p->tls_id]) continue;
1052 memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
1053 memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
1054 p->tls_size - p->tls_len);
1055 if (p->tls_id == (size_t)self->dtv[0]) break;
1056 }
1057 }
1058
1059 void *__copy_tls(unsigned char *mem)
1060 {
1061 pthread_t td;
1062 struct dso *p;
1063 void **dtv;
1064
1065 #ifdef TLS_ABOVE_TP
1066 dtv = (void **)(mem + libc.tls_size) - (tls_cnt + 1);
1067
1068 mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
1069 td = (pthread_t)mem;
1070 mem += sizeof(struct pthread);
1071
1072 for (p=head; p; p=p->next) {
1073 if (!p->tls_id) continue;
1074 dtv[p->tls_id] = mem + p->tls_offset;
1075 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1076 }
1077 #else
1078 dtv = (void **)mem;
1079
1080 mem += libc.tls_size - sizeof(struct pthread);
1081 mem -= (uintptr_t)mem & (tls_align-1);
1082 td = (pthread_t)mem;
1083
1084 for (p=head; p; p=p->next) {
1085 if (!p->tls_id) continue;
1086 dtv[p->tls_id] = mem - p->tls_offset;
1087 memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
1088 }
1089 #endif
1090 dtv[0] = (void *)tls_cnt;
1091 td->dtv = td->dtv_copy = dtv;
1092 return td;
1093 }
1094
1095 __attribute__((__visibility__("hidden")))
1096 void *__tls_get_new(size_t *v)
1097 {
1098 pthread_t self = __pthread_self();
1099
1100 /* Block signals to make accessing new TLS async-signal-safe */
1101 sigset_t set;
1102 __block_all_sigs(&set);
1103 if (v[0]<=(size_t)self->dtv[0]) {
1104 __restore_sigs(&set);
1105 return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
1106 }
1107
1108 /* This is safe without any locks held because, if the caller
1109 * is able to request the Nth entry of the DTV, the DSO list
1110 * must be valid at least that far out and it was synchronized
1111 * at program startup or by an already-completed call to dlopen. */
1112 struct dso *p;
1113 for (p=head; p->tls_id != v[0]; p=p->next);
1114
1115 /* Get new DTV space from new DSO if needed */
1116 if (v[0] > (size_t)self->dtv[0]) {
1117 void **newdtv = p->new_dtv +
1118 (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
1119 memcpy(newdtv, self->dtv,
1120 ((size_t)self->dtv[0]+1) * sizeof(void *));
1121 newdtv[0] = (void *)v[0];
1122 self->dtv = self->dtv_copy = newdtv;
1123 }
1124
1125 /* Get new TLS memory from all new DSOs up to the requested one */
1126 unsigned char *mem;
1127 for (p=head; ; p=p->next) {
1128 if (!p->tls_id || self->dtv[p->tls_id]) continue;
1129 mem = p->new_tls + (p->tls_size + p->tls_align)
1130 * a_fetch_add(&p->new_tls_idx,1);
1131 mem += ((uintptr_t)p->tls_image - (uintptr_t)mem)
1132 & (p->tls_align-1);
1133 self->dtv[p->tls_id] = mem;
1134 memcpy(mem, p->tls_image, p->tls_len);
1135 if (p->tls_id == v[0]) break;
1136 }
1137 __restore_sigs(&set);
1138 return mem + v[1] + DTP_OFFSET;
1139 }
1140
1141 static void update_tls_size()
1142 {
1143 libc.tls_size = ALIGN(
1144 (1+tls_cnt) * sizeof(void *) +
1145 tls_offset +
1146 sizeof(struct pthread) +
1147 tls_align * 2,
1148 tls_align);
1149 }
1150
1151 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1152 * following stage 2 and stage 3 functions via primitive symbolic lookup
1153 * since it does not have access to their addresses to begin with. */
1154
1155 /* Stage 2 of the dynamic linker is called after relative relocations
1156 * have been processed. It can make function calls to static functions
1157 * and access string literals and static data, but cannot use extern
1158 * symbols. Its job is to perform symbolic relocations on the dynamic
1159 * linker itself, but some of the relocations performed may need to be
1160 * replaced later due to copy relocations in the main program. */
1161
1162 void __dls2(unsigned char *base, size_t *sp)
1163 {
1164 Ehdr *ehdr = (void *)base;
1165 ldso.base = base;
1166 ldso.name = ldso.shortname = "libc.so";
1167 ldso.global = 1;
1168 ldso.phnum = ehdr->e_phnum;
1169 ldso.phdr = (void *)(base + ehdr->e_phoff);
1170 ldso.phentsize = ehdr->e_phentsize;
1171 kernel_mapped_dso(&ldso);
1172 decode_dyn(&ldso);
1173
1174 /* Prepare storage for to save clobbered REL addends so they
1175 * can be reused in stage 3. There should be very few. If
1176 * something goes wrong and there are a huge number, abort
1177 * instead of risking stack overflow. */
1178 size_t dyn[DYN_CNT];
1179 decode_vec(ldso.dynv, dyn, DYN_CNT);
1180 size_t *rel = (void *)(base+dyn[DT_REL]);
1181 size_t rel_size = dyn[DT_RELSZ];
1182 size_t symbolic_rel_cnt = 0;
1183 apply_addends_to = rel;
1184 for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t))
1185 if (!IS_RELATIVE(rel[1])) symbolic_rel_cnt++;
1186 if (symbolic_rel_cnt >= ADDEND_LIMIT) a_crash();
1187 size_t addends[symbolic_rel_cnt+1];
1188 saved_addends = addends;
1189
1190 head = &ldso;
1191 reloc_all(&ldso);
1192
1193 ldso.relocated = 0;
1194
1195 /* Call dynamic linker stage-3, __dls3, looking it up
1196 * symbolically as a barrier against moving the address
1197 * load across the above relocation processing. */
1198 struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
1199 ((stage3_func)(ldso.base+dls3_def.sym->st_value))(sp);
1200 }
1201
1202 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1203 * fully functional. Its job is to load (if not already loaded) and
1204 * process dependencies and relocations for the main application and
1205 * transfer control to its entry point. */
1206
1207 _Noreturn void __dls3(size_t *sp)
1208 {
1209 static struct dso app, vdso;
1210 size_t aux[AUX_CNT], *auxv;
1211 size_t i;
1212 char *env_preload=0;
1213 size_t vdso_base;
1214 int argc = *sp;
1215 char **argv = (void *)(sp+1);
1216 char **argv_orig = argv;
1217 char **envp = argv+argc+1;
1218
1219 /* Find aux vector just past environ[] and use it to initialize
1220 * global data that may be needed before we can make syscalls. */
1221 __environ = envp;
1222 for (i=argc+1; argv[i]; i++);
1223 libc.auxv = auxv = (void *)(argv+i+1);
1224 decode_vec(auxv, aux, AUX_CNT);
1225 __hwcap = aux[AT_HWCAP];
1226 libc.page_size = aux[AT_PAGESZ];
1227 libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
1228 || aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
1229
1230 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1231 * use during dynamic linking. If possible it will also serve as the
1232 * thread pointer at runtime. */
1233 libc.tls_size = sizeof builtin_tls;
1234 if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
1235 a_crash();
1236 }
1237
1238 /* Only trust user/env if kernel says we're not suid/sgid */
1239 if (!libc.secure) {
1240 env_path = getenv("LD_LIBRARY_PATH");
1241 env_preload = getenv("LD_PRELOAD");
1242 }
1243
1244 /* If the main program was already loaded by the kernel,
1245 * AT_PHDR will point to some location other than the dynamic
1246 * linker's program headers. */
1247 if (aux[AT_PHDR] != (size_t)ldso.phdr) {
1248 size_t interp_off = 0;
1249 size_t tls_image = 0;
1250 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1251 Phdr *phdr = app.phdr = (void *)aux[AT_PHDR];
1252 app.phnum = aux[AT_PHNUM];
1253 app.phentsize = aux[AT_PHENT];
1254 for (i=aux[AT_PHNUM]; i; i--, phdr=(void *)((char *)phdr + aux[AT_PHENT])) {
1255 if (phdr->p_type == PT_PHDR)
1256 app.base = (void *)(aux[AT_PHDR] - phdr->p_vaddr);
1257 else if (phdr->p_type == PT_INTERP)
1258 interp_off = (size_t)phdr->p_vaddr;
1259 else if (phdr->p_type == PT_TLS) {
1260 tls_image = phdr->p_vaddr;
1261 app.tls_len = phdr->p_filesz;
1262 app.tls_size = phdr->p_memsz;
1263 app.tls_align = phdr->p_align;
1264 }
1265 }
1266 if (app.tls_size) app.tls_image = (char *)app.base + tls_image;
1267 if (interp_off) ldso.name = (char *)app.base + interp_off;
1268 if ((aux[0] & (1UL<<AT_EXECFN))
1269 && strncmp((char *)aux[AT_EXECFN], "/proc/", 6))
1270 app.name = (char *)aux[AT_EXECFN];
1271 else
1272 app.name = argv[0];
1273 kernel_mapped_dso(&app);
1274 } else {
1275 int fd;
1276 char *ldname = argv[0];
1277 size_t l = strlen(ldname);
1278 if (l >= 3 && !strcmp(ldname+l-3, "ldd")) ldd_mode = 1;
1279 argv++;
1280 while (argv[0] && argv[0][0]=='-' && argv[0][1]=='-') {
1281 char *opt = argv[0]+2;
1282 *argv++ = (void *)-1;
1283 if (!*opt) {
1284 break;
1285 } else if (!memcmp(opt, "list", 5)) {
1286 ldd_mode = 1;
1287 } else if (!memcmp(opt, "library-path", 12)) {
1288 if (opt[12]=='=') env_path = opt+13;
1289 else if (opt[12]) *argv = 0;
1290 else if (*argv) env_path = *argv++;
1291 } else if (!memcmp(opt, "preload", 7)) {
1292 if (opt[7]=='=') env_preload = opt+8;
1293 else if (opt[7]) *argv = 0;
1294 else if (*argv) env_preload = *argv++;
1295 } else {
1296 argv[0] = 0;
1297 }
1298 }
1299 argv[-1] = (void *)(argc - (argv-argv_orig));
1300 if (!argv[0]) {
1301 dprintf(2, "musl libc\n"
1302 "Version %s\n"
1303 "Dynamic Program Loader\n"
1304 "Usage: %s [options] [--] pathname%s\n",
1305 __libc_get_version(), ldname,
1306 ldd_mode ? "" : " [args]");
1307 _exit(1);
1308 }
1309 fd = open(argv[0], O_RDONLY);
1310 if (fd < 0) {
1311 dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
1312 _exit(1);
1313 }
1314 runtime = 1;
1315 Ehdr *ehdr = (void *)map_library(fd, &app);
1316 if (!ehdr) {
1317 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
1318 _exit(1);
1319 }
1320 runtime = 0;
1321 close(fd);
1322 ldso.name = ldname;
1323 app.name = argv[0];
1324 aux[AT_ENTRY] = (size_t)app.base + ehdr->e_entry;
1325 /* Find the name that would have been used for the dynamic
1326 * linker had ldd not taken its place. */
1327 if (ldd_mode) {
1328 for (i=0; i<app.phnum; i++) {
1329 if (app.phdr[i].p_type == PT_INTERP)
1330 ldso.name = (void *)(app.base
1331 + app.phdr[i].p_vaddr);
1332 }
1333 dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
1334 }
1335 }
1336 if (app.tls_size) {
1337 app.tls_id = tls_cnt = 1;
1338 #ifdef TLS_ABOVE_TP
1339 app.tls_offset = 0;
1340 tls_offset = app.tls_size
1341 + ( -((uintptr_t)app.tls_image + app.tls_size)
1342 & (app.tls_align-1) );
1343 #else
1344 tls_offset = app.tls_offset = app.tls_size
1345 + ( -((uintptr_t)app.tls_image + app.tls_size)
1346 & (app.tls_align-1) );
1347 #endif
1348 tls_align = MAXP2(tls_align, app.tls_align);
1349 }
1350 app.global = 1;
1351 decode_dyn(&app);
1352
1353 /* Attach to vdso, if provided by the kernel */
1354 if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
1355 Ehdr *ehdr = (void *)vdso_base;
1356 Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
1357 vdso.phnum = ehdr->e_phnum;
1358 vdso.phentsize = ehdr->e_phentsize;
1359 for (i=ehdr->e_phnum; i; i--, phdr=(void *)((char *)phdr + ehdr->e_phentsize)) {
1360 if (phdr->p_type == PT_DYNAMIC)
1361 vdso.dynv = (void *)(vdso_base + phdr->p_offset);
1362 if (phdr->p_type == PT_LOAD)
1363 vdso.base = (void *)(vdso_base - phdr->p_vaddr + phdr->p_offset);
1364 }
1365 vdso.name = "";
1366 vdso.shortname = "linux-gate.so.1";
1367 vdso.global = 1;
1368 vdso.relocated = 1;
1369 decode_dyn(&vdso);
1370 vdso.prev = &ldso;
1371 ldso.next = &vdso;
1372 }
1373
1374 /* Initial dso chain consists only of the app. */
1375 head = tail = &app;
1376
1377 /* Donate unused parts of app and library mapping to malloc */
1378 reclaim_gaps(&app);
1379 reclaim_gaps(&ldso);
1380
1381 /* Load preload/needed libraries, add their symbols to the global
1382 * namespace, and perform all remaining relocations. */
1383 if (env_preload) load_preload(env_preload);
1384 load_deps(&app);
1385 make_global(&app);
1386
1387 #ifndef DYNAMIC_IS_RO
1388 for (i=0; app.dynv[i]; i+=2)
1389 if (app.dynv[i]==DT_DEBUG)
1390 app.dynv[i+1] = (size_t)&debug;
1391 #endif
1392
1393 /* The main program must be relocated LAST since it may contin
1394 * copy relocations which depend on libraries' relocations. */
1395 reloc_all(app.next);
1396 reloc_all(&app);
1397
1398 update_tls_size();
1399 if (libc.tls_size > sizeof builtin_tls || tls_align > MIN_TLS_ALIGN) {
1400 void *initial_tls = calloc(libc.tls_size, 1);
1401 if (!initial_tls) {
1402 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1403 argv[0], libc.tls_size);
1404 _exit(127);
1405 }
1406 if (__init_tp(__copy_tls(initial_tls)) < 0) {
1407 a_crash();
1408 }
1409 } else {
1410 size_t tmp_tls_size = libc.tls_size;
1411 pthread_t self = __pthread_self();
1412 /* Temporarily set the tls size to the full size of
1413 * builtin_tls so that __copy_tls will use the same layout
1414 * as it did for before. Then check, just to be safe. */
1415 libc.tls_size = sizeof builtin_tls;
1416 if (__copy_tls((void*)builtin_tls) != self) a_crash();
1417 libc.tls_size = tmp_tls_size;
1418 }
1419 static_tls_cnt = tls_cnt;
1420
1421 if (ldso_fail) _exit(127);
1422 if (ldd_mode) _exit(0);
1423
1424 /* Switch to runtime mode: any further failures in the dynamic
1425 * linker are a reportable failure rather than a fatal startup
1426 * error. */
1427 runtime = 1;
1428
1429 debug.ver = 1;
1430 debug.bp = dl_debug_state;
1431 debug.head = head;
1432 debug.base = ldso.base;
1433 debug.state = 0;
1434 _dl_debug_state();
1435
1436 __init_libc(envp, argv[0]);
1437 atexit(do_fini);
1438 errno = 0;
1439 do_init_fini(tail);
1440
1441 CRTJMP((void *)aux[AT_ENTRY], argv-1);
1442 for(;;);
1443 }
1444
1445 void *dlopen(const char *file, int mode)
1446 {
1447 struct dso *volatile p, *orig_tail, *next;
1448 size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
1449 size_t i;
1450 int cs;
1451 jmp_buf jb;
1452
1453 if (!file) return head;
1454
1455 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
1456 pthread_rwlock_wrlock(&lock);
1457 __inhibit_ptc();
1458
1459 p = 0;
1460 orig_tls_cnt = tls_cnt;
1461 orig_tls_offset = tls_offset;
1462 orig_tls_align = tls_align;
1463 orig_tail = tail;
1464 noload = mode & RTLD_NOLOAD;
1465
1466 rtld_fail = &jb;
1467 if (setjmp(*rtld_fail)) {
1468 /* Clean up anything new that was (partially) loaded */
1469 if (p && p->deps) for (i=0; p->deps[i]; i++)
1470 if (p->deps[i]->global < 0)
1471 p->deps[i]->global = 0;
1472 for (p=orig_tail->next; p; p=next) {
1473 next = p->next;
1474 munmap(p->map, p->map_len);
1475 while (p->td_index) {
1476 void *tmp = p->td_index->next;
1477 free(p->td_index);
1478 p->td_index = tmp;
1479 }
1480 if (p->rpath != p->rpath_orig)
1481 free(p->rpath);
1482 free(p->deps);
1483 free(p);
1484 }
1485 tls_cnt = orig_tls_cnt;
1486 tls_offset = orig_tls_offset;
1487 tls_align = orig_tls_align;
1488 tail = orig_tail;
1489 tail->next = 0;
1490 p = 0;
1491 goto end;
1492 } else p = load_library(file, head);
1493
1494 if (!p) {
1495 error(noload ?
1496 "Library %s is not already loaded" :
1497 "Error loading shared library %s: %m",
1498 file);
1499 goto end;
1500 }
1501
1502 /* First load handling */
1503 if (!p->deps) {
1504 load_deps(p);
1505 if (p->deps) for (i=0; p->deps[i]; i++)
1506 if (!p->deps[i]->global)
1507 p->deps[i]->global = -1;
1508 if (!p->global) p->global = -1;
1509 reloc_all(p);
1510 if (p->deps) for (i=0; p->deps[i]; i++)
1511 if (p->deps[i]->global < 0)
1512 p->deps[i]->global = 0;
1513 if (p->global < 0) p->global = 0;
1514 }
1515
1516 if (mode & RTLD_GLOBAL) {
1517 if (p->deps) for (i=0; p->deps[i]; i++)
1518 p->deps[i]->global = 1;
1519 p->global = 1;
1520 }
1521
1522 update_tls_size();
1523 _dl_debug_state();
1524 orig_tail = tail;
1525 end:
1526 __release_ptc();
1527 if (p) gencnt++;
1528 pthread_rwlock_unlock(&lock);
1529 if (p) do_init_fini(orig_tail);
1530 pthread_setcancelstate(cs, 0);
1531 return p;
1532 }
1533
1534 static int invalid_dso_handle(void *h)
1535 {
1536 struct dso *p;
1537 for (p=head; p; p=p->next) if (h==p) return 0;
1538 error("Invalid library handle %p", (void *)h);
1539 return 1;
1540 }
1541
1542 void *__tls_get_addr(size_t *);
1543
1544 static void *do_dlsym(struct dso *p, const char *s, void *ra)
1545 {
1546 size_t i;
1547 uint32_t h = 0, gh = 0;
1548 Sym *sym;
1549 if (p == head || p == RTLD_DEFAULT || p == RTLD_NEXT) {
1550 if (p == RTLD_DEFAULT) {
1551 p = head;
1552 } else if (p == RTLD_NEXT) {
1553 for (p=head; p && (unsigned char *)ra-p->map>p->map_len; p=p->next);
1554 if (!p) p=head;
1555 p = p->next;
1556 }
1557 struct symdef def = find_sym(p, s, 0);
1558 if (!def.sym) goto failed;
1559 if ((def.sym->st_info&0xf) == STT_TLS)
1560 return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
1561 return def.dso->base + def.sym->st_value;
1562 }
1563 if (invalid_dso_handle(p))
1564 return 0;
1565 if (p->ghashtab) {
1566 gh = gnu_hash(s);
1567 sym = gnu_lookup(s, gh, p);
1568 } else {
1569 h = sysv_hash(s);
1570 sym = sysv_lookup(s, h, p);
1571 }
1572 if (sym && (sym->st_info&0xf) == STT_TLS)
1573 return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
1574 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1575 return p->base + sym->st_value;
1576 if (p->deps) for (i=0; p->deps[i]; i++) {
1577 if (p->deps[i]->ghashtab) {
1578 if (!gh) gh = gnu_hash(s);
1579 sym = gnu_lookup(s, gh, p->deps[i]);
1580 } else {
1581 if (!h) h = sysv_hash(s);
1582 sym = sysv_lookup(s, h, p->deps[i]);
1583 }
1584 if (sym && (sym->st_info&0xf) == STT_TLS)
1585 return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
1586 if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
1587 return p->deps[i]->base + sym->st_value;
1588 }
1589 failed:
1590 error("Symbol not found: %s", s);
1591 return 0;
1592 }
1593
1594 int __dladdr(const void *addr, Dl_info *info)
1595 {
1596 struct dso *p;
1597 Sym *sym;
1598 uint32_t nsym;
1599 char *strings;
1600 size_t i;
1601 void *best = 0;
1602 char *bestname;
1603
1604 pthread_rwlock_rdlock(&lock);
1605 for (p=head; p && (unsigned char *)addr-p->map>p->map_len; p=p->next);
1606 pthread_rwlock_unlock(&lock);
1607
1608 if (!p) return 0;
1609
1610 sym = p->syms;
1611 strings = p->strings;
1612 if (p->hashtab) {
1613 nsym = p->hashtab[1];
1614 } else {
1615 uint32_t *buckets;
1616 uint32_t *hashval;
1617 buckets = p->ghashtab + 4 + (p->ghashtab[2]*sizeof(size_t)/4);
1618 sym += p->ghashtab[1];
1619 for (i = nsym = 0; i < p->ghashtab[0]; i++) {
1620 if (buckets[i] > nsym)
1621 nsym = buckets[i];
1622 }
1623 if (nsym) {
1624 nsym -= p->ghashtab[1];
1625 hashval = buckets + p->ghashtab[0] + nsym;
1626 do nsym++;
1627 while (!(*hashval++ & 1));
1628 }
1629 }
1630
1631 for (; nsym; nsym--, sym++) {
1632 if (sym->st_value
1633 && (1<<(sym->st_info&0xf) & OK_TYPES)
1634 && (1<<(sym->st_info>>4) & OK_BINDS)) {
1635 void *symaddr = p->base + sym->st_value;
1636 if (symaddr > addr || symaddr < best)
1637 continue;
1638 best = symaddr;
1639 bestname = strings + sym->st_name;
1640 if (addr == symaddr)
1641 break;
1642 }
1643 }
1644
1645 if (!best) return 0;
1646
1647 info->dli_fname = p->name;
1648 info->dli_fbase = p->base;
1649 info->dli_sname = bestname;
1650 info->dli_saddr = best;
1651
1652 return 1;
1653 }
1654
1655 __attribute__((__visibility__("hidden")))
1656 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1657 {
1658 void *res;
1659 pthread_rwlock_rdlock(&lock);
1660 res = do_dlsym(p, s, ra);
1661 pthread_rwlock_unlock(&lock);
1662 return res;
1663 }
1664
1665 int dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
1666 {
1667 struct dso *current;
1668 struct dl_phdr_info info;
1669 int ret = 0;
1670 for(current = head; current;) {
1671 info.dlpi_addr = (uintptr_t)current->base;
1672 info.dlpi_name = current->name;
1673 info.dlpi_phdr = current->phdr;
1674 info.dlpi_phnum = current->phnum;
1675 info.dlpi_adds = gencnt;
1676 info.dlpi_subs = 0;
1677 info.dlpi_tls_modid = current->tls_id;
1678 info.dlpi_tls_data = current->tls_image;
1679
1680 ret = (callback)(&info, sizeof (info), data);
1681
1682 if (ret != 0) break;
1683
1684 pthread_rwlock_rdlock(&lock);
1685 current = current->next;
1686 pthread_rwlock_unlock(&lock);
1687 }
1688 return ret;
1689 }
1690 #else
1691 static int invalid_dso_handle(void *h)
1692 {
1693 error("Invalid library handle %p", (void *)h);
1694 return 1;
1695 }
1696 void *dlopen(const char *file, int mode)
1697 {
1698 error("Dynamic loading not supported");
1699 return 0;
1700 }
1701 void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
1702 {
1703 error("Symbol not found: %s", s);
1704 return 0;
1705 }
1706 int __dladdr (const void *addr, Dl_info *info)
1707 {
1708 return 0;
1709 }
1710 #endif
1711
1712 int __dlinfo(void *dso, int req, void *res)
1713 {
1714 if (invalid_dso_handle(dso)) return -1;
1715 if (req != RTLD_DI_LINKMAP) {
1716 error("Unsupported request %d", req);
1717 return -1;
1718 }
1719 *(struct link_map **)res = dso;
1720 return 0;
1721 }
1722
1723 char *dlerror()
1724 {
1725 pthread_t self = __pthread_self();
1726 if (!self->dlerror_flag) return 0;
1727 self->dlerror_flag = 0;
1728 char *s = self->dlerror_buf;
1729 if (s == (void *)-1)
1730 return "Dynamic linker failed to allocate memory for error message";
1731 else
1732 return s;
1733 }
1734
1735 int dlclose(void *p)
1736 {
1737 return invalid_dso_handle(p);
1738 }
1739
1740 void __dl_thread_cleanup(void)
1741 {
1742 pthread_t self = __pthread_self();
1743 if (self->dlerror_buf != (void *)-1)
1744 free(self->dlerror_buf);
1745 }
1746
1747 static void error(const char *fmt, ...)
1748 {
1749 va_list ap;
1750 va_start(ap, fmt);
1751 #ifdef SHARED
1752 if (!runtime) {
1753 vdprintf(2, fmt, ap);
1754 dprintf(2, "\n");
1755 ldso_fail = 1;
1756 va_end(ap);
1757 return;
1758 }
1759 #endif
1760 pthread_t self = __pthread_self();
1761 if (self->dlerror_buf != (void *)-1)
1762 free(self->dlerror_buf);
1763 size_t len = vsnprintf(0, 0, fmt, ap);
1764 va_end(ap);
1765 char *buf = malloc(len+1);
1766 if (buf) {
1767 va_start(ap, fmt);
1768 vsnprintf(buf, len+1, fmt, ap);
1769 va_end(ap);
1770 } else {
1771 buf = (void *)-1;
1772 }
1773 self->dlerror_buf = buf;
1774 self->dlerror_flag = 1;
1775 }
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