20 #include "pthread_impl.h"
24 static void error(const char *, ...);
26 #define MAXP2(a,b) (-(-(a)&-(b)))
27 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
39 struct td_index
*next
;
44 struct fdpic_loadmap
*loadmap
;
50 struct dso
*next
, *prev
;
69 struct dso
**deps
, *needed_by
;
70 char *rpath_orig
, *rpath
;
71 struct tls_module tls
;
73 size_t relro_start
, relro_end
;
75 unsigned char *new_tls
;
76 volatile int new_dtv_idx
, new_tls_idx
;
77 struct td_index
*td_index
;
78 struct dso
*fini_next
;
83 struct fdpic_loadmap
*loadmap
;
98 int __init_tp(void *);
99 void __init_libc(char **, char *);
100 void *__copy_tls(unsigned char *);
102 __attribute__((__visibility__("hidden")))
103 const char *__libc_get_version(void);
105 static struct builtin_tls
{
110 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
112 #define ADDEND_LIMIT 4096
113 static size_t *saved_addends
, *apply_addends_to
;
115 static struct dso ldso
;
116 static struct dso
*head
, *tail
, *fini_head
;
117 static char *env_path
, *sys_path
;
118 static unsigned long long gencnt
;
121 static int ldso_fail
;
123 static jmp_buf *rtld_fail
;
124 static pthread_rwlock_t lock
;
125 static struct debug debug
;
126 static struct tls_module
*tls_tail
;
127 static size_t tls_cnt
, tls_offset
, tls_align
= MIN_TLS_ALIGN
;
128 static size_t static_tls_cnt
;
129 static pthread_mutex_t init_fini_lock
= { ._m_type
= PTHREAD_MUTEX_RECURSIVE
};
130 static struct fdpic_loadmap
*app_loadmap
;
131 static struct fdpic_dummy_loadmap app_dummy_loadmap
;
133 struct debug
*_dl_debug_addr
= &debug
;
135 __attribute__((__visibility__("hidden")))
136 void (*const __init_array_start
)(void)=0, (*const __fini_array_start
)(void)=0;
138 __attribute__((__visibility__("hidden")))
139 extern void (*const __init_array_end
)(void), (*const __fini_array_end
)(void);
141 weak_alias(__init_array_start
, __init_array_end
);
142 weak_alias(__fini_array_start
, __fini_array_end
);
144 static int dl_strcmp(const char *l
, const char *r
)
146 for (; *l
==*r
&& *l
; l
++, r
++);
147 return *(unsigned char *)l
- *(unsigned char *)r
;
149 #define strcmp(l,r) dl_strcmp(l,r)
151 /* Compute load address for a virtual address in a given dso. */
153 static void *laddr(const struct dso
*p
, size_t v
)
156 if (!p
->loadmap
) return p
->base
+ v
;
157 for (j
=0; v
-p
->loadmap
->segs
[j
].p_vaddr
>= p
->loadmap
->segs
[j
].p_memsz
; j
++);
158 return (void *)(v
- p
->loadmap
->segs
[j
].p_vaddr
+ p
->loadmap
->segs
[j
].addr
);
160 #define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
161 laddr(p, v), (p)->got })
163 #define laddr(p, v) (void *)((p)->base + (v))
164 #define fpaddr(p, v) ((void (*)())laddr(p, v))
167 static void decode_vec(size_t *v
, size_t *a
, size_t cnt
)
170 for (i
=0; i
<cnt
; i
++) a
[i
] = 0;
171 for (; v
[0]; v
+=2) if (v
[0]-1<cnt
-1) {
177 static int search_vec(size_t *v
, size_t *r
, size_t key
)
179 for (; v
[0]!=key
; v
+=2)
185 static uint32_t sysv_hash(const char *s0
)
187 const unsigned char *s
= (void *)s0
;
193 return h
& 0xfffffff;
196 static uint32_t gnu_hash(const char *s0
)
198 const unsigned char *s
= (void *)s0
;
199 uint_fast32_t h
= 5381;
205 static Sym
*sysv_lookup(const char *s
, uint32_t h
, struct dso
*dso
)
208 Sym
*syms
= dso
->syms
;
209 Elf_Symndx
*hashtab
= dso
->hashtab
;
210 char *strings
= dso
->strings
;
211 for (i
=hashtab
[2+h
%hashtab
[0]]; i
; i
=hashtab
[2+hashtab
[0]+i
]) {
212 if ((!dso
->versym
|| dso
->versym
[i
] >= 0)
213 && (!strcmp(s
, strings
+syms
[i
].st_name
)))
219 static Sym
*gnu_lookup(uint32_t h1
, uint32_t *hashtab
, struct dso
*dso
, const char *s
)
221 uint32_t nbuckets
= hashtab
[0];
222 uint32_t *buckets
= hashtab
+ 4 + hashtab
[2]*(sizeof(size_t)/4);
223 uint32_t i
= buckets
[h1
% nbuckets
];
227 uint32_t *hashval
= buckets
+ nbuckets
+ (i
- hashtab
[1]);
229 for (h1
|= 1; ; i
++) {
230 uint32_t h2
= *hashval
++;
231 if ((h1
== (h2
|1)) && (!dso
->versym
|| dso
->versym
[i
] >= 0)
232 && !strcmp(s
, dso
->strings
+ dso
->syms
[i
].st_name
))
240 static Sym
*gnu_lookup_filtered(uint32_t h1
, uint32_t *hashtab
, struct dso
*dso
, const char *s
, uint32_t fofs
, size_t fmask
)
242 const size_t *bloomwords
= (const void *)(hashtab
+4);
243 size_t f
= bloomwords
[fofs
& (hashtab
[2]-1)];
244 if (!(f
& fmask
)) return 0;
246 f
>>= (h1
>> hashtab
[3]) % (8 * sizeof f
);
247 if (!(f
& 1)) return 0;
249 return gnu_lookup(h1
, hashtab
, dso
, s
);
252 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
253 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
255 #ifndef ARCH_SYM_REJECT_UND
256 #define ARCH_SYM_REJECT_UND(s) 0
259 static struct symdef
find_sym(struct dso
*dso
, const char *s
, int need_def
)
261 uint32_t h
= 0, gh
, gho
, *ght
;
263 struct symdef def
= {0};
264 for (; dso
; dso
=dso
->next
) {
266 if (!dso
->global
) continue;
267 if ((ght
= dso
->ghashtab
)) {
270 int maskbits
= 8 * sizeof ghm
;
272 ghm
= 1ul << gh
% maskbits
;
274 sym
= gnu_lookup_filtered(gh
, ght
, dso
, s
, gho
, ghm
);
276 if (!h
) h
= sysv_hash(s
);
277 sym
= sysv_lookup(s
, h
, dso
);
281 if (need_def
|| (sym
->st_info
&0xf) == STT_TLS
282 || ARCH_SYM_REJECT_UND(sym
))
285 if ((sym
->st_info
&0xf) != STT_TLS
)
287 if (!(1<<(sym
->st_info
&0xf) & OK_TYPES
)) continue;
288 if (!(1<<(sym
->st_info
>>4) & OK_BINDS
)) continue;
290 if (def
.sym
&& sym
->st_info
>>4 == STB_WEAK
) continue;
293 if (sym
->st_info
>>4 == STB_GLOBAL
) break;
298 __attribute__((__visibility__("hidden")))
299 ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
301 static void do_relocs(struct dso
*dso
, size_t *rel
, size_t rel_size
, size_t stride
)
303 unsigned char *base
= dso
->base
;
304 Sym
*syms
= dso
->syms
;
305 char *strings
= dso
->strings
;
316 int skip_relative
= 0, reuse_addends
= 0, save_slot
= 0;
319 /* Only ldso's REL table needs addend saving/reuse. */
320 if (rel
== apply_addends_to
)
325 for (; rel_size
; rel
+=stride
, rel_size
-=stride
*sizeof(size_t)) {
326 if (skip_relative
&& IS_RELATIVE(rel
[1], dso
->syms
)) continue;
327 type
= R_TYPE(rel
[1]);
328 if (type
== REL_NONE
) continue;
329 sym_index
= R_SYM(rel
[1]);
330 reloc_addr
= laddr(dso
, rel
[0]);
332 sym
= syms
+ sym_index
;
333 name
= strings
+ sym
->st_name
;
334 ctx
= type
==REL_COPY
? head
->next
: head
;
335 def
= (sym
->st_info
&0xf) == STT_SECTION
336 ? (struct symdef
){ .dso
= dso
, .sym
= sym
}
337 : find_sym(ctx
, name
, type
==REL_PLT
);
338 if (!def
.sym
&& (sym
->st_shndx
!= SHN_UNDEF
339 || sym
->st_info
>>4 != STB_WEAK
)) {
340 error("Error relocating %s: %s: symbol not found",
342 if (runtime
) longjmp(*rtld_fail
, 1);
353 } else if (type
==REL_GOT
|| type
==REL_PLT
|| type
==REL_COPY
) {
355 } else if (reuse_addends
) {
356 /* Save original addend in stage 2 where the dso
357 * chain consists of just ldso; otherwise read back
358 * saved addend since the inline one was clobbered. */
360 saved_addends
[save_slot
] = *reloc_addr
;
361 addend
= saved_addends
[save_slot
++];
363 addend
= *reloc_addr
;
366 sym_val
= def
.sym
? (size_t)laddr(def
.dso
, def
.sym
->st_value
) : 0;
367 tls_val
= def
.sym
? def
.sym
->st_value
: 0;
373 addend
-= (size_t)reloc_addr
;
377 *reloc_addr
= sym_val
+ addend
;
380 *reloc_addr
= (size_t)base
+ addend
;
383 if (sym
) *reloc_addr
= sym_val
+ addend
;
384 else *reloc_addr
= (size_t)base
+ addend
;
387 memcpy(reloc_addr
, (void *)sym_val
, sym
->st_size
);
390 *(uint32_t *)reloc_addr
= sym_val
+ addend
391 - (size_t)reloc_addr
;
394 *reloc_addr
= def
.sym
? (size_t)(def
.dso
->funcdescs
395 + (def
.sym
- def
.dso
->syms
)) : 0;
397 case REL_FUNCDESC_VAL
:
398 if ((sym
->st_info
&0xf) == STT_SECTION
) *reloc_addr
+= sym_val
;
399 else *reloc_addr
= sym_val
;
400 reloc_addr
[1] = def
.sym
? (size_t)def
.dso
->got
: 0;
403 *reloc_addr
= def
.dso
->tls_id
;
406 *reloc_addr
= tls_val
+ addend
- DTP_OFFSET
;
410 *reloc_addr
= tls_val
+ def
.dso
->tls
.offset
+ TPOFF_K
+ addend
;
414 *reloc_addr
= tls_val
- def
.dso
->tls
.offset
+ addend
;
417 *reloc_addr
= def
.dso
->tls
.offset
- tls_val
+ addend
;
421 if (stride
<3) addend
= reloc_addr
[1];
422 if (runtime
&& def
.dso
->tls_id
>= static_tls_cnt
) {
423 struct td_index
*new = malloc(sizeof *new);
426 "Error relocating %s: cannot allocate TLSDESC for %s",
427 dso
->name
, sym
? name
: "(local)" );
428 longjmp(*rtld_fail
, 1);
430 new->next
= dso
->td_index
;
432 new->args
[0] = def
.dso
->tls_id
;
433 new->args
[1] = tls_val
+ addend
;
434 reloc_addr
[0] = (size_t)__tlsdesc_dynamic
;
435 reloc_addr
[1] = (size_t)new;
437 reloc_addr
[0] = (size_t)__tlsdesc_static
;
439 reloc_addr
[1] = tls_val
+ def
.dso
->tls
.offset
442 reloc_addr
[1] = tls_val
- def
.dso
->tls
.offset
448 error("Error relocating %s: unsupported relocation type %d",
450 if (runtime
) longjmp(*rtld_fail
, 1);
456 /* A huge hack: to make up for the wastefulness of shared libraries
457 * needing at least a page of dirty memory even if they have no global
458 * data, we reclaim the gaps at the beginning and end of writable maps
459 * and "donate" them to the heap by setting up minimal malloc
460 * structures and then freeing them. */
462 static void reclaim(struct dso
*dso
, size_t start
, size_t end
)
465 if (start
>= dso
->relro_start
&& start
< dso
->relro_end
) start
= dso
->relro_end
;
466 if (end
>= dso
->relro_start
&& end
< dso
->relro_end
) end
= dso
->relro_start
;
467 start
= start
+ 6*sizeof(size_t)-1 & -4*sizeof(size_t);
468 end
= (end
& -4*sizeof(size_t)) - 2*sizeof(size_t);
469 if (start
>end
|| end
-start
< 4*sizeof(size_t)) return;
470 a
= laddr(dso
, start
);
473 a
[-1] = z
[0] = end
-start
+ 2*sizeof(size_t) | 1;
478 static void reclaim_gaps(struct dso
*dso
)
480 Phdr
*ph
= dso
->phdr
;
481 size_t phcnt
= dso
->phnum
;
483 if (DL_FDPIC
) return; // FIXME
484 for (; phcnt
--; ph
=(void *)((char *)ph
+dso
->phentsize
)) {
485 if (ph
->p_type
!=PT_LOAD
) continue;
486 if ((ph
->p_flags
&(PF_R
|PF_W
))!=(PF_R
|PF_W
)) continue;
487 reclaim(dso
, ph
->p_vaddr
& -PAGE_SIZE
, ph
->p_vaddr
);
488 reclaim(dso
, ph
->p_vaddr
+ph
->p_memsz
,
489 ph
->p_vaddr
+ph
->p_memsz
+PAGE_SIZE
-1 & -PAGE_SIZE
);
493 static void *mmap_fixed(void *p
, size_t n
, int prot
, int flags
, int fd
, off_t off
)
495 static int no_map_fixed
;
498 q
= mmap(p
, n
, prot
, flags
|MAP_FIXED
, fd
, off
);
499 if (!DL_NOMMU_SUPPORT
|| q
!= MAP_FAILED
|| errno
!= EINVAL
)
503 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
504 if (flags
& MAP_ANONYMOUS
) {
509 if (lseek(fd
, off
, SEEK_SET
) < 0) return MAP_FAILED
;
510 for (q
=p
; n
; q
+=r
, off
+=r
, n
-=r
) {
512 if (r
< 0 && errno
!= EINTR
) return MAP_FAILED
;
521 static void unmap_library(struct dso
*dso
)
525 for (i
=0; i
<dso
->loadmap
->nsegs
; i
++) {
526 if (!dso
->loadmap
->segs
[i
].p_memsz
)
528 munmap((void *)dso
->loadmap
->segs
[i
].addr
,
529 dso
->loadmap
->segs
[i
].p_memsz
);
532 } else if (dso
->map
&& dso
->map_len
) {
533 munmap(dso
->map
, dso
->map_len
);
537 static void *map_library(int fd
, struct dso
*dso
)
539 Ehdr buf
[(896+sizeof(Ehdr
))/sizeof(Ehdr
)];
540 void *allocated_buf
=0;
542 size_t addr_min
=SIZE_MAX
, addr_max
=0, map_len
;
543 size_t this_min
, this_max
;
549 unsigned char *map
=MAP_FAILED
, *base
;
554 ssize_t l
= read(fd
, buf
, sizeof buf
);
557 if (l
<sizeof *eh
|| (eh
->e_type
!= ET_DYN
&& eh
->e_type
!= ET_EXEC
))
559 phsize
= eh
->e_phentsize
* eh
->e_phnum
;
560 if (phsize
> sizeof buf
- sizeof *eh
) {
561 allocated_buf
= malloc(phsize
);
562 if (!allocated_buf
) return 0;
563 l
= pread(fd
, allocated_buf
, phsize
, eh
->e_phoff
);
564 if (l
< 0) goto error
;
565 if (l
!= phsize
) goto noexec
;
566 ph
= ph0
= allocated_buf
;
567 } else if (eh
->e_phoff
+ phsize
> l
) {
568 l
= pread(fd
, buf
+1, phsize
, eh
->e_phoff
);
569 if (l
< 0) goto error
;
570 if (l
!= phsize
) goto noexec
;
571 ph
= ph0
= (void *)(buf
+ 1);
573 ph
= ph0
= (void *)((char *)buf
+ eh
->e_phoff
);
575 for (i
=eh
->e_phnum
; i
; i
--, ph
=(void *)((char *)ph
+eh
->e_phentsize
)) {
576 if (ph
->p_type
== PT_DYNAMIC
) {
578 } else if (ph
->p_type
== PT_TLS
) {
579 tls_image
= ph
->p_vaddr
;
580 dso
->tls
.align
= ph
->p_align
;
581 dso
->tls
.len
= ph
->p_filesz
;
582 dso
->tls
.size
= ph
->p_memsz
;
583 } else if (ph
->p_type
== PT_GNU_RELRO
) {
584 dso
->relro_start
= ph
->p_vaddr
& -PAGE_SIZE
;
585 dso
->relro_end
= (ph
->p_vaddr
+ ph
->p_memsz
) & -PAGE_SIZE
;
587 if (ph
->p_type
!= PT_LOAD
) continue;
589 if (ph
->p_vaddr
< addr_min
) {
590 addr_min
= ph
->p_vaddr
;
591 off_start
= ph
->p_offset
;
592 prot
= (((ph
->p_flags
&PF_R
) ? PROT_READ
: 0) |
593 ((ph
->p_flags
&PF_W
) ? PROT_WRITE
: 0) |
594 ((ph
->p_flags
&PF_X
) ? PROT_EXEC
: 0));
596 if (ph
->p_vaddr
+ph
->p_memsz
> addr_max
) {
597 addr_max
= ph
->p_vaddr
+ph
->p_memsz
;
600 if (!dyn
) goto noexec
;
601 if (DL_FDPIC
&& !(eh
->e_flags
& FDPIC_CONSTDISP_FLAG
)) {
602 dso
->loadmap
= calloc(1, sizeof *dso
->loadmap
603 + nsegs
* sizeof *dso
->loadmap
->segs
);
604 if (!dso
->loadmap
) goto error
;
605 dso
->loadmap
->nsegs
= nsegs
;
606 for (ph
=ph0
, i
=0; i
<nsegs
; ph
=(void *)((char *)ph
+eh
->e_phentsize
)) {
607 if (ph
->p_type
!= PT_LOAD
) continue;
608 prot
= (((ph
->p_flags
&PF_R
) ? PROT_READ
: 0) |
609 ((ph
->p_flags
&PF_W
) ? PROT_WRITE
: 0) |
610 ((ph
->p_flags
&PF_X
) ? PROT_EXEC
: 0));
611 map
= mmap(0, ph
->p_memsz
+ (ph
->p_vaddr
& PAGE_SIZE
-1),
613 fd
, ph
->p_offset
& -PAGE_SIZE
);
614 if (map
== MAP_FAILED
) {
618 dso
->loadmap
->segs
[i
].addr
= (size_t)map
+
619 (ph
->p_vaddr
& PAGE_SIZE
-1);
620 dso
->loadmap
->segs
[i
].p_vaddr
= ph
->p_vaddr
;
621 dso
->loadmap
->segs
[i
].p_memsz
= ph
->p_memsz
;
623 if (prot
& PROT_WRITE
) {
624 size_t brk
= (ph
->p_vaddr
& PAGE_SIZE
-1)
626 size_t pgbrk
= brk
+ PAGE_SIZE
-1 & -PAGE_SIZE
;
627 size_t pgend
= brk
+ ph
->p_memsz
- ph
->p_filesz
628 + PAGE_SIZE
-1 & -PAGE_SIZE
;
629 if (pgend
> pgbrk
&& mmap_fixed(map
+pgbrk
,
631 MAP_PRIVATE
|MAP_FIXED
|MAP_ANONYMOUS
,
632 -1, off_start
) == MAP_FAILED
)
634 memset(map
+ brk
, 0, pgbrk
-brk
);
637 map
= (void *)dso
->loadmap
->segs
[0].addr
;
641 addr_max
+= PAGE_SIZE
-1;
642 addr_max
&= -PAGE_SIZE
;
643 addr_min
&= -PAGE_SIZE
;
644 off_start
&= -PAGE_SIZE
;
645 map_len
= addr_max
- addr_min
+ off_start
;
646 /* The first time, we map too much, possibly even more than
647 * the length of the file. This is okay because we will not
648 * use the invalid part; we just need to reserve the right
649 * amount of virtual address space to map over later. */
650 map
= DL_NOMMU_SUPPORT
651 ? mmap((void *)addr_min
, map_len
, PROT_READ
|PROT_WRITE
|PROT_EXEC
,
652 MAP_PRIVATE
|MAP_ANONYMOUS
, -1, 0)
653 : mmap((void *)addr_min
, map_len
, prot
,
654 MAP_PRIVATE
, fd
, off_start
);
655 if (map
==MAP_FAILED
) goto error
;
657 dso
->map_len
= map_len
;
658 /* If the loaded file is not relocatable and the requested address is
659 * not available, then the load operation must fail. */
660 if (eh
->e_type
!= ET_DYN
&& addr_min
&& map
!=(void *)addr_min
) {
664 base
= map
- addr_min
;
667 for (ph
=ph0
, i
=eh
->e_phnum
; i
; i
--, ph
=(void *)((char *)ph
+eh
->e_phentsize
)) {
668 if (ph
->p_type
!= PT_LOAD
) continue;
669 /* Check if the programs headers are in this load segment, and
670 * if so, record the address for use by dl_iterate_phdr. */
671 if (!dso
->phdr
&& eh
->e_phoff
>= ph
->p_offset
672 && eh
->e_phoff
+phsize
<= ph
->p_offset
+ph
->p_filesz
) {
673 dso
->phdr
= (void *)(base
+ ph
->p_vaddr
674 + (eh
->e_phoff
-ph
->p_offset
));
675 dso
->phnum
= eh
->e_phnum
;
676 dso
->phentsize
= eh
->e_phentsize
;
678 /* Reuse the existing mapping for the lowest-address LOAD */
679 if ((ph
->p_vaddr
& -PAGE_SIZE
) == addr_min
&& !DL_NOMMU_SUPPORT
)
681 this_min
= ph
->p_vaddr
& -PAGE_SIZE
;
682 this_max
= ph
->p_vaddr
+ph
->p_memsz
+PAGE_SIZE
-1 & -PAGE_SIZE
;
683 off_start
= ph
->p_offset
& -PAGE_SIZE
;
684 prot
= (((ph
->p_flags
&PF_R
) ? PROT_READ
: 0) |
685 ((ph
->p_flags
&PF_W
) ? PROT_WRITE
: 0) |
686 ((ph
->p_flags
&PF_X
) ? PROT_EXEC
: 0));
687 if (mmap_fixed(base
+this_min
, this_max
-this_min
, prot
, MAP_PRIVATE
|MAP_FIXED
, fd
, off_start
) == MAP_FAILED
)
689 if (ph
->p_memsz
> ph
->p_filesz
) {
690 size_t brk
= (size_t)base
+ph
->p_vaddr
+ph
->p_filesz
;
691 size_t pgbrk
= brk
+PAGE_SIZE
-1 & -PAGE_SIZE
;
692 memset((void *)brk
, 0, pgbrk
-brk
& PAGE_SIZE
-1);
693 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
)
697 for (i
=0; ((size_t *)(base
+dyn
))[i
]; i
+=2)
698 if (((size_t *)(base
+dyn
))[i
]==DT_TEXTREL
) {
699 if (mprotect(map
, map_len
, PROT_READ
|PROT_WRITE
|PROT_EXEC
)
706 dso
->dynv
= laddr(dso
, dyn
);
707 if (dso
->tls
.size
) dso
->tls
.image
= laddr(dso
, tls_image
);
708 if (!runtime
) reclaim_gaps(dso
);
714 if (map
!=MAP_FAILED
) unmap_library(dso
);
719 static int path_open(const char *name
, const char *s
, char *buf
, size_t buf_size
)
724 s
+= strspn(s
, ":\n");
725 l
= strcspn(s
, ":\n");
726 if (l
-1 >= INT_MAX
) return -1;
727 if (snprintf(buf
, buf_size
, "%.*s/%s", (int)l
, s
, name
) < buf_size
) {
728 if ((fd
= open(buf
, O_RDONLY
|O_CLOEXEC
))>=0) return fd
;
736 /* Any negative value but -1 will inhibit
737 * futher path search. */
745 static int fixup_rpath(struct dso
*p
, char *buf
, size_t buf_size
)
748 const char *s
, *t
, *origin
;
750 if (p
->rpath
|| !p
->rpath_orig
) return 0;
751 if (!strchr(p
->rpath_orig
, '$')) {
752 p
->rpath
= p
->rpath_orig
;
757 while ((t
=strchr(s
, '$'))) {
758 if (strncmp(t
, "$ORIGIN", 7) && strncmp(t
, "${ORIGIN}", 9))
763 if (n
> SSIZE_MAX
/PATH_MAX
) return 0;
765 if (p
->kernel_mapped
) {
766 /* $ORIGIN searches cannot be performed for the main program
767 * when it is suid/sgid/AT_SECURE. This is because the
768 * pathname is under the control of the caller of execve.
769 * For libraries, however, $ORIGIN can be processed safely
770 * since the library's pathname came from a trusted source
771 * (either system paths or a call to dlopen). */
774 l
= readlink("/proc/self/exe", buf
, buf_size
);
775 if (l
== -1) switch (errno
) {
790 t
= strrchr(origin
, '/');
791 l
= t
? t
-origin
: 0;
792 p
->rpath
= malloc(strlen(p
->rpath_orig
) + n
*l
+ 1);
793 if (!p
->rpath
) return -1;
797 while ((t
=strchr(s
, '$'))) {
800 memcpy(d
, origin
, l
);
802 /* It was determined previously that the '$' is followed
803 * either by "ORIGIN" or "{ORIGIN}". */
804 s
= t
+ 7 + 2*(t
[1]=='{');
810 static void decode_dyn(struct dso
*p
)
813 decode_vec(p
->dynv
, dyn
, DYN_CNT
);
814 p
->syms
= laddr(p
, dyn
[DT_SYMTAB
]);
815 p
->strings
= laddr(p
, dyn
[DT_STRTAB
]);
816 if (dyn
[0]&(1<<DT_HASH
))
817 p
->hashtab
= laddr(p
, dyn
[DT_HASH
]);
818 if (dyn
[0]&(1<<DT_RPATH
))
819 p
->rpath_orig
= p
->strings
+ dyn
[DT_RPATH
];
820 if (dyn
[0]&(1<<DT_RUNPATH
))
821 p
->rpath_orig
= p
->strings
+ dyn
[DT_RUNPATH
];
822 if (dyn
[0]&(1<<DT_PLTGOT
))
823 p
->got
= laddr(p
, dyn
[DT_PLTGOT
]);
824 if (search_vec(p
->dynv
, dyn
, DT_GNU_HASH
))
825 p
->ghashtab
= laddr(p
, *dyn
);
826 if (search_vec(p
->dynv
, dyn
, DT_VERSYM
))
827 p
->versym
= laddr(p
, *dyn
);
830 static size_t count_syms(struct dso
*p
)
832 if (p
->hashtab
) return p
->hashtab
[1];
835 uint32_t *buckets
= p
->ghashtab
+ 4 + (p
->ghashtab
[2]*sizeof(size_t)/4);
837 for (i
= nsym
= 0; i
< p
->ghashtab
[0]; i
++) {
838 if (buckets
[i
] > nsym
)
842 hashval
= buckets
+ p
->ghashtab
[0] + (nsym
- p
->ghashtab
[1]);
844 while (!(*hashval
++ & 1));
849 static void *dl_mmap(size_t n
)
852 int prot
= PROT_READ
|PROT_WRITE
, flags
= MAP_ANONYMOUS
|MAP_PRIVATE
;
854 p
= (void *)__syscall(SYS_mmap2
, 0, n
, prot
, flags
, -1, 0);
856 p
= (void *)__syscall(SYS_mmap
, 0, n
, prot
, flags
, -1, 0);
858 return p
== MAP_FAILED
? 0 : p
;
861 static void makefuncdescs(struct dso
*p
)
863 static int self_done
;
864 size_t nsym
= count_syms(p
);
865 size_t i
, size
= nsym
* sizeof(*p
->funcdescs
);
868 p
->funcdescs
= dl_mmap(size
);
871 p
->funcdescs
= malloc(size
);
874 if (!runtime
) a_crash();
875 error("Error allocating function descriptors for %s", p
->name
);
876 longjmp(*rtld_fail
, 1);
878 for (i
=0; i
<nsym
; i
++) {
879 if ((p
->syms
[i
].st_info
&0xf)==STT_FUNC
&& p
->syms
[i
].st_shndx
) {
880 p
->funcdescs
[i
].addr
= laddr(p
, p
->syms
[i
].st_value
);
881 p
->funcdescs
[i
].got
= p
->got
;
883 p
->funcdescs
[i
].addr
= 0;
884 p
->funcdescs
[i
].got
= 0;
889 static struct dso
*load_library(const char *name
, struct dso
*needed_by
)
891 char buf
[2*NAME_MAX
+2];
892 const char *pathname
;
894 struct dso
*p
, temp_dso
= {0};
906 /* Catch and block attempts to reload the implementation itself */
907 if (name
[0]=='l' && name
[1]=='i' && name
[2]=='b') {
908 static const char reserved
[] =
909 "c.pthread.rt.m.dl.util.xnet.";
910 const char *rp
, *next
;
911 for (rp
=reserved
; *rp
; rp
=next
) {
912 next
= strchr(rp
, '.') + 1;
913 if (strncmp(name
+3, rp
, next
-rp
) == 0)
918 /* Track which names have been resolved
919 * and only report each one once. */
920 static unsigned reported
;
921 unsigned mask
= 1U<<(rp
-reserved
);
922 if (!(reported
& mask
)) {
924 dprintf(1, "\t%s => %s (%p)\n",
932 if (!strcmp(name
, ldso
.name
)) is_self
= 1;
937 tail
= ldso
.next
? ldso
.next
: &ldso
;
941 if (strchr(name
, '/')) {
943 fd
= open(name
, O_RDONLY
|O_CLOEXEC
);
945 /* Search for the name to see if it's already loaded */
946 for (p
=head
->next
; p
; p
=p
->next
) {
947 if (p
->shortname
&& !strcmp(p
->shortname
, name
)) {
952 if (strlen(name
) > NAME_MAX
) return 0;
954 if (env_path
) fd
= path_open(name
, env_path
, buf
, sizeof buf
);
955 for (p
=needed_by
; fd
== -1 && p
; p
=p
->needed_by
) {
956 if (fixup_rpath(p
, buf
, sizeof buf
) < 0)
957 fd
= -2; /* Inhibit further search. */
959 fd
= path_open(name
, p
->rpath
, buf
, sizeof buf
);
965 if (ldso
.name
[0]=='/') {
967 for (s
=t
=z
=ldso
.name
; *s
; s
++)
968 if (*s
=='/') z
=t
, t
=s
;
969 prefix_len
= z
-ldso
.name
;
970 if (prefix_len
< PATH_MAX
)
977 char etc_ldso_path
[prefix_len
+ 1
978 + sizeof "/etc/ld-musl-" LDSO_ARCH
".path"];
979 snprintf(etc_ldso_path
, sizeof etc_ldso_path
,
980 "%.*s/etc/ld-musl-" LDSO_ARCH
".path",
981 (int)prefix_len
, prefix
);
982 FILE *f
= fopen(etc_ldso_path
, "rbe");
984 if (getdelim(&sys_path
, (size_t[1]){0}, 0, f
) <= 0) {
989 } else if (errno
!= ENOENT
) {
993 if (!sys_path
) sys_path
= "/lib:/usr/local/lib:/usr/lib";
994 fd
= path_open(name
, sys_path
, buf
, sizeof buf
);
998 if (fd
< 0) return 0;
999 if (fstat(fd
, &st
) < 0) {
1003 for (p
=head
->next
; p
; p
=p
->next
) {
1004 if (p
->dev
== st
.st_dev
&& p
->ino
== st
.st_ino
) {
1005 /* If this library was previously loaded with a
1006 * pathname but a search found the same inode,
1007 * setup its shortname so it can be found by name. */
1008 if (!p
->shortname
&& pathname
!= name
)
1009 p
->shortname
= strrchr(p
->name
, '/')+1;
1015 map
= noload
? 0 : map_library(fd
, &temp_dso
);
1019 /* Allocate storage for the new DSO. When there is TLS, this
1020 * storage must include a reservation for all pre-existing
1021 * threads to obtain copies of both the new TLS, and an
1022 * extended DTV capable of storing an additional slot for
1023 * the newly-loaded DSO. */
1024 alloc_size
= sizeof *p
+ strlen(pathname
) + 1;
1025 if (runtime
&& temp_dso
.tls
.image
) {
1026 size_t per_th
= temp_dso
.tls
.size
+ temp_dso
.tls
.align
1027 + sizeof(void *) * (tls_cnt
+3);
1028 n_th
= libc
.threads_minus_1
+ 1;
1029 if (n_th
> SSIZE_MAX
/ per_th
) alloc_size
= SIZE_MAX
;
1030 else alloc_size
+= n_th
* per_th
;
1032 p
= calloc(1, alloc_size
);
1034 unmap_library(&temp_dso
);
1037 memcpy(p
, &temp_dso
, sizeof temp_dso
);
1042 p
->needed_by
= needed_by
;
1044 strcpy(p
->name
, pathname
);
1045 /* Add a shortname only if name arg was not an explicit pathname. */
1046 if (pathname
!= name
) p
->shortname
= strrchr(p
->name
, '/')+1;
1048 p
->tls_id
= ++tls_cnt
;
1049 tls_align
= MAXP2(tls_align
, p
->tls
.align
);
1051 p
->tls
.offset
= tls_offset
+ ( (tls_align
-1) &
1052 -(tls_offset
+ (uintptr_t)p
->tls
.image
) );
1053 tls_offset
+= p
->tls
.size
;
1055 tls_offset
+= p
->tls
.size
+ p
->tls
.align
- 1;
1056 tls_offset
-= (tls_offset
+ (uintptr_t)p
->tls
.image
)
1058 p
->tls
.offset
= tls_offset
;
1060 p
->new_dtv
= (void *)(-sizeof(size_t) &
1061 (uintptr_t)(p
->name
+strlen(p
->name
)+sizeof(size_t)));
1062 p
->new_tls
= (void *)(p
->new_dtv
+ n_th
*(tls_cnt
+1));
1063 if (tls_tail
) tls_tail
->next
= &p
->tls
;
1064 else libc
.tls_head
= &p
->tls
;
1072 if (DL_FDPIC
) makefuncdescs(p
);
1074 if (ldd_mode
) dprintf(1, "\t%s => %s (%p)\n", name
, pathname
, p
->base
);
1079 static void load_deps(struct dso
*p
)
1082 struct dso
***deps
= &p
->deps
, **tmp
, *dep
;
1083 for (; p
; p
=p
->next
) {
1084 for (i
=0; p
->dynv
[i
]; i
+=2) {
1085 if (p
->dynv
[i
] != DT_NEEDED
) continue;
1086 dep
= load_library(p
->strings
+ p
->dynv
[i
+1], p
);
1088 error("Error loading shared library %s: %m (needed by %s)",
1089 p
->strings
+ p
->dynv
[i
+1], p
->name
);
1090 if (runtime
) longjmp(*rtld_fail
, 1);
1094 tmp
= realloc(*deps
, sizeof(*tmp
)*(ndeps
+2));
1095 if (!tmp
) longjmp(*rtld_fail
, 1);
1104 static void load_preload(char *s
)
1108 for (z
=s
; *z
; s
=z
) {
1109 for ( ; *s
&& (isspace(*s
) || *s
==':'); s
++);
1110 for (z
=s
; *z
&& !isspace(*z
) && *z
!=':'; z
++);
1118 static void make_global(struct dso
*p
)
1120 for (; p
; p
=p
->next
) p
->global
= 1;
1123 static void do_mips_relocs(struct dso
*p
, size_t *got
)
1125 size_t i
, j
, rel
[2];
1126 unsigned char *base
= p
->base
;
1127 i
=0; search_vec(p
->dynv
, &i
, DT_MIPS_LOCAL_GOTNO
);
1131 while (i
--) *got
++ += (size_t)base
;
1133 j
=0; search_vec(p
->dynv
, &j
, DT_MIPS_GOTSYM
);
1134 i
=0; search_vec(p
->dynv
, &i
, DT_MIPS_SYMTABNO
);
1135 Sym
*sym
= p
->syms
+ j
;
1136 rel
[0] = (unsigned char *)got
- base
;
1137 for (i
-=j
; i
; i
--, sym
++, rel
[0]+=sizeof(size_t)) {
1138 rel
[1] = R_INFO(sym
-p
->syms
, R_MIPS_JUMP_SLOT
);
1139 do_relocs(p
, rel
, sizeof rel
, 2);
1143 static void reloc_all(struct dso
*p
)
1145 size_t dyn
[DYN_CNT
];
1146 for (; p
; p
=p
->next
) {
1147 if (p
->relocated
) continue;
1148 decode_vec(p
->dynv
, dyn
, DYN_CNT
);
1149 if (NEED_MIPS_GOT_RELOCS
)
1150 do_mips_relocs(p
, laddr(p
, dyn
[DT_PLTGOT
]));
1151 do_relocs(p
, laddr(p
, dyn
[DT_JMPREL
]), dyn
[DT_PLTRELSZ
],
1152 2+(dyn
[DT_PLTREL
]==DT_RELA
));
1153 do_relocs(p
, laddr(p
, dyn
[DT_REL
]), dyn
[DT_RELSZ
], 2);
1154 do_relocs(p
, laddr(p
, dyn
[DT_RELA
]), dyn
[DT_RELASZ
], 3);
1156 if (head
!= &ldso
&& p
->relro_start
!= p
->relro_end
&&
1157 mprotect(laddr(p
, p
->relro_start
), p
->relro_end
-p
->relro_start
, PROT_READ
)
1158 && errno
!= ENOSYS
) {
1159 error("Error relocating %s: RELRO protection failed: %m",
1161 if (runtime
) longjmp(*rtld_fail
, 1);
1168 static void kernel_mapped_dso(struct dso
*p
)
1170 size_t min_addr
= -1, max_addr
= 0, cnt
;
1172 for (cnt
= p
->phnum
; cnt
--; ph
= (void *)((char *)ph
+ p
->phentsize
)) {
1173 if (ph
->p_type
== PT_DYNAMIC
) {
1174 p
->dynv
= laddr(p
, ph
->p_vaddr
);
1175 } else if (ph
->p_type
== PT_GNU_RELRO
) {
1176 p
->relro_start
= ph
->p_vaddr
& -PAGE_SIZE
;
1177 p
->relro_end
= (ph
->p_vaddr
+ ph
->p_memsz
) & -PAGE_SIZE
;
1179 if (ph
->p_type
!= PT_LOAD
) continue;
1180 if (ph
->p_vaddr
< min_addr
)
1181 min_addr
= ph
->p_vaddr
;
1182 if (ph
->p_vaddr
+ph
->p_memsz
> max_addr
)
1183 max_addr
= ph
->p_vaddr
+ph
->p_memsz
;
1185 min_addr
&= -PAGE_SIZE
;
1186 max_addr
= (max_addr
+ PAGE_SIZE
-1) & -PAGE_SIZE
;
1187 p
->map
= p
->base
+ min_addr
;
1188 p
->map_len
= max_addr
- min_addr
;
1189 p
->kernel_mapped
= 1;
1192 void __libc_exit_fini()
1195 size_t dyn
[DYN_CNT
];
1196 for (p
=fini_head
; p
; p
=p
->fini_next
) {
1197 if (!p
->constructed
) continue;
1198 decode_vec(p
->dynv
, dyn
, DYN_CNT
);
1199 if (dyn
[0] & (1<<DT_FINI_ARRAY
)) {
1200 size_t n
= dyn
[DT_FINI_ARRAYSZ
]/sizeof(size_t);
1201 size_t *fn
= (size_t *)laddr(p
, dyn
[DT_FINI_ARRAY
])+n
;
1202 while (n
--) ((void (*)(void))*--fn
)();
1204 #ifndef NO_LEGACY_INITFINI
1205 if ((dyn
[0] & (1<<DT_FINI
)) && dyn
[DT_FINI
])
1206 fpaddr(p
, dyn
[DT_FINI
])();
1211 static void do_init_fini(struct dso
*p
)
1213 size_t dyn
[DYN_CNT
];
1214 int need_locking
= libc
.threads_minus_1
;
1215 /* Allow recursive calls that arise when a library calls
1216 * dlopen from one of its constructors, but block any
1217 * other threads until all ctors have finished. */
1218 if (need_locking
) pthread_mutex_lock(&init_fini_lock
);
1219 for (; p
; p
=p
->prev
) {
1220 if (p
->constructed
) continue;
1222 decode_vec(p
->dynv
, dyn
, DYN_CNT
);
1223 if (dyn
[0] & ((1<<DT_FINI
) | (1<<DT_FINI_ARRAY
))) {
1224 p
->fini_next
= fini_head
;
1227 #ifndef NO_LEGACY_INITFINI
1228 if ((dyn
[0] & (1<<DT_INIT
)) && dyn
[DT_INIT
])
1229 fpaddr(p
, dyn
[DT_INIT
])();
1231 if (dyn
[0] & (1<<DT_INIT_ARRAY
)) {
1232 size_t n
= dyn
[DT_INIT_ARRAYSZ
]/sizeof(size_t);
1233 size_t *fn
= laddr(p
, dyn
[DT_INIT_ARRAY
]);
1234 while (n
--) ((void (*)(void))*fn
++)();
1236 if (!need_locking
&& libc
.threads_minus_1
) {
1238 pthread_mutex_lock(&init_fini_lock
);
1241 if (need_locking
) pthread_mutex_unlock(&init_fini_lock
);
1244 void __libc_start_init(void)
1249 static void dl_debug_state(void)
1253 weak_alias(dl_debug_state
, _dl_debug_state
);
1255 void __init_tls(size_t *auxv
)
1259 __attribute__((__visibility__("hidden")))
1260 void *__tls_get_new(tls_mod_off_t
*v
)
1262 pthread_t self
= __pthread_self();
1264 /* Block signals to make accessing new TLS async-signal-safe */
1266 __block_all_sigs(&set
);
1267 if (v
[0]<=(size_t)self
->dtv
[0]) {
1268 __restore_sigs(&set
);
1269 return (char *)self
->dtv
[v
[0]]+v
[1]+DTP_OFFSET
;
1272 /* This is safe without any locks held because, if the caller
1273 * is able to request the Nth entry of the DTV, the DSO list
1274 * must be valid at least that far out and it was synchronized
1275 * at program startup or by an already-completed call to dlopen. */
1277 for (p
=head
; p
->tls_id
!= v
[0]; p
=p
->next
);
1279 /* Get new DTV space from new DSO if needed */
1280 if (v
[0] > (size_t)self
->dtv
[0]) {
1281 void **newdtv
= p
->new_dtv
+
1282 (v
[0]+1)*a_fetch_add(&p
->new_dtv_idx
,1);
1283 memcpy(newdtv
, self
->dtv
,
1284 ((size_t)self
->dtv
[0]+1) * sizeof(void *));
1285 newdtv
[0] = (void *)v
[0];
1286 self
->dtv
= self
->dtv_copy
= newdtv
;
1289 /* Get new TLS memory from all new DSOs up to the requested one */
1291 for (p
=head
; ; p
=p
->next
) {
1292 if (!p
->tls_id
|| self
->dtv
[p
->tls_id
]) continue;
1293 mem
= p
->new_tls
+ (p
->tls
.size
+ p
->tls
.align
)
1294 * a_fetch_add(&p
->new_tls_idx
,1);
1295 mem
+= ((uintptr_t)p
->tls
.image
- (uintptr_t)mem
)
1297 self
->dtv
[p
->tls_id
] = mem
;
1298 memcpy(mem
, p
->tls
.image
, p
->tls
.len
);
1299 if (p
->tls_id
== v
[0]) break;
1301 __restore_sigs(&set
);
1302 return mem
+ v
[1] + DTP_OFFSET
;
1305 static void update_tls_size()
1307 libc
.tls_cnt
= tls_cnt
;
1308 libc
.tls_align
= tls_align
;
1309 libc
.tls_size
= ALIGN(
1310 (1+tls_cnt
) * sizeof(void *) +
1312 sizeof(struct pthread
) +
1317 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1318 * following stage 2 and stage 3 functions via primitive symbolic lookup
1319 * since it does not have access to their addresses to begin with. */
1321 /* Stage 2 of the dynamic linker is called after relative relocations
1322 * have been processed. It can make function calls to static functions
1323 * and access string literals and static data, but cannot use extern
1324 * symbols. Its job is to perform symbolic relocations on the dynamic
1325 * linker itself, but some of the relocations performed may need to be
1326 * replaced later due to copy relocations in the main program. */
1328 __attribute__((__visibility__("hidden")))
1329 void __dls2(unsigned char *base
, size_t *sp
)
1332 void *p1
= (void *)sp
[-2];
1333 void *p2
= (void *)sp
[-1];
1335 size_t *auxv
, aux
[AUX_CNT
];
1336 for (auxv
=sp
+1+*sp
+1; *auxv
; auxv
++); auxv
++;
1337 decode_vec(auxv
, aux
, AUX_CNT
);
1338 if (aux
[AT_BASE
]) ldso
.base
= (void *)aux
[AT_BASE
];
1339 else ldso
.base
= (void *)(aux
[AT_PHDR
] & -4096);
1341 app_loadmap
= p2
? p1
: 0;
1342 ldso
.loadmap
= p2
? p2
: p1
;
1343 ldso
.base
= laddr(&ldso
, 0);
1347 Ehdr
*ehdr
= (void *)ldso
.base
;
1348 ldso
.name
= ldso
.shortname
= "libc.so";
1350 ldso
.phnum
= ehdr
->e_phnum
;
1351 ldso
.phdr
= laddr(&ldso
, ehdr
->e_phoff
);
1352 ldso
.phentsize
= ehdr
->e_phentsize
;
1353 kernel_mapped_dso(&ldso
);
1356 if (DL_FDPIC
) makefuncdescs(&ldso
);
1358 /* Prepare storage for to save clobbered REL addends so they
1359 * can be reused in stage 3. There should be very few. If
1360 * something goes wrong and there are a huge number, abort
1361 * instead of risking stack overflow. */
1362 size_t dyn
[DYN_CNT
];
1363 decode_vec(ldso
.dynv
, dyn
, DYN_CNT
);
1364 size_t *rel
= laddr(&ldso
, dyn
[DT_REL
]);
1365 size_t rel_size
= dyn
[DT_RELSZ
];
1366 size_t symbolic_rel_cnt
= 0;
1367 apply_addends_to
= rel
;
1368 for (; rel_size
; rel
+=2, rel_size
-=2*sizeof(size_t))
1369 if (!IS_RELATIVE(rel
[1], ldso
.syms
)) symbolic_rel_cnt
++;
1370 if (symbolic_rel_cnt
>= ADDEND_LIMIT
) a_crash();
1371 size_t addends
[symbolic_rel_cnt
+1];
1372 saved_addends
= addends
;
1379 /* Call dynamic linker stage-3, __dls3, looking it up
1380 * symbolically as a barrier against moving the address
1381 * load across the above relocation processing. */
1382 struct symdef dls3_def
= find_sym(&ldso
, "__dls3", 0);
1383 if (DL_FDPIC
) ((stage3_func
)&ldso
.funcdescs
[dls3_def
.sym
-ldso
.syms
])(sp
);
1384 else ((stage3_func
)laddr(&ldso
, dls3_def
.sym
->st_value
))(sp
);
1387 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1388 * fully functional. Its job is to load (if not already loaded) and
1389 * process dependencies and relocations for the main application and
1390 * transfer control to its entry point. */
1392 _Noreturn
void __dls3(size_t *sp
)
1394 static struct dso app
, vdso
;
1395 size_t aux
[AUX_CNT
], *auxv
;
1397 char *env_preload
=0;
1400 char **argv
= (void *)(sp
+1);
1401 char **argv_orig
= argv
;
1402 char **envp
= argv
+argc
+1;
1404 /* Find aux vector just past environ[] and use it to initialize
1405 * global data that may be needed before we can make syscalls. */
1407 for (i
=argc
+1; argv
[i
]; i
++);
1408 libc
.auxv
= auxv
= (void *)(argv
+i
+1);
1409 decode_vec(auxv
, aux
, AUX_CNT
);
1410 __hwcap
= aux
[AT_HWCAP
];
1411 libc
.page_size
= aux
[AT_PAGESZ
];
1412 libc
.secure
= ((aux
[0]&0x7800)!=0x7800 || aux
[AT_UID
]!=aux
[AT_EUID
]
1413 || aux
[AT_GID
]!=aux
[AT_EGID
] || aux
[AT_SECURE
]);
1415 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1416 * use during dynamic linking. If possible it will also serve as the
1417 * thread pointer at runtime. */
1418 libc
.tls_size
= sizeof builtin_tls
;
1419 libc
.tls_align
= tls_align
;
1420 if (__init_tp(__copy_tls((void *)builtin_tls
)) < 0) {
1424 /* Only trust user/env if kernel says we're not suid/sgid */
1426 env_path
= getenv("LD_LIBRARY_PATH");
1427 env_preload
= getenv("LD_PRELOAD");
1430 /* If the main program was already loaded by the kernel,
1431 * AT_PHDR will point to some location other than the dynamic
1432 * linker's program headers. */
1433 if (aux
[AT_PHDR
] != (size_t)ldso
.phdr
) {
1434 size_t interp_off
= 0;
1435 size_t tls_image
= 0;
1436 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1437 Phdr
*phdr
= app
.phdr
= (void *)aux
[AT_PHDR
];
1438 app
.phnum
= aux
[AT_PHNUM
];
1439 app
.phentsize
= aux
[AT_PHENT
];
1440 for (i
=aux
[AT_PHNUM
]; i
; i
--, phdr
=(void *)((char *)phdr
+ aux
[AT_PHENT
])) {
1441 if (phdr
->p_type
== PT_PHDR
)
1442 app
.base
= (void *)(aux
[AT_PHDR
] - phdr
->p_vaddr
);
1443 else if (phdr
->p_type
== PT_INTERP
)
1444 interp_off
= (size_t)phdr
->p_vaddr
;
1445 else if (phdr
->p_type
== PT_TLS
) {
1446 tls_image
= phdr
->p_vaddr
;
1447 app
.tls
.len
= phdr
->p_filesz
;
1448 app
.tls
.size
= phdr
->p_memsz
;
1449 app
.tls
.align
= phdr
->p_align
;
1452 if (DL_FDPIC
) app
.loadmap
= app_loadmap
;
1453 if (app
.tls
.size
) app
.tls
.image
= laddr(&app
, tls_image
);
1454 if (interp_off
) ldso
.name
= laddr(&app
, interp_off
);
1455 if ((aux
[0] & (1UL<<AT_EXECFN
))
1456 && strncmp((char *)aux
[AT_EXECFN
], "/proc/", 6))
1457 app
.name
= (char *)aux
[AT_EXECFN
];
1460 kernel_mapped_dso(&app
);
1463 char *ldname
= argv
[0];
1464 size_t l
= strlen(ldname
);
1465 if (l
>= 3 && !strcmp(ldname
+l
-3, "ldd")) ldd_mode
= 1;
1467 while (argv
[0] && argv
[0][0]=='-' && argv
[0][1]=='-') {
1468 char *opt
= argv
[0]+2;
1469 *argv
++ = (void *)-1;
1472 } else if (!memcmp(opt
, "list", 5)) {
1474 } else if (!memcmp(opt
, "library-path", 12)) {
1475 if (opt
[12]=='=') env_path
= opt
+13;
1476 else if (opt
[12]) *argv
= 0;
1477 else if (*argv
) env_path
= *argv
++;
1478 } else if (!memcmp(opt
, "preload", 7)) {
1479 if (opt
[7]=='=') env_preload
= opt
+8;
1480 else if (opt
[7]) *argv
= 0;
1481 else if (*argv
) env_preload
= *argv
++;
1486 argv
[-1] = (void *)(argc
- (argv
-argv_orig
));
1488 dprintf(2, "musl libc (" LDSO_ARCH
")\n"
1490 "Dynamic Program Loader\n"
1491 "Usage: %s [options] [--] pathname%s\n",
1492 __libc_get_version(), ldname
,
1493 ldd_mode
? "" : " [args]");
1496 fd
= open(argv
[0], O_RDONLY
);
1498 dprintf(2, "%s: cannot load %s: %s\n", ldname
, argv
[0], strerror(errno
));
1502 Ehdr
*ehdr
= (void *)map_library(fd
, &app
);
1504 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname
, argv
[0]);
1511 aux
[AT_ENTRY
] = (size_t)laddr(&app
, ehdr
->e_entry
);
1512 /* Find the name that would have been used for the dynamic
1513 * linker had ldd not taken its place. */
1515 for (i
=0; i
<app
.phnum
; i
++) {
1516 if (app
.phdr
[i
].p_type
== PT_INTERP
)
1517 ldso
.name
= laddr(&app
, app
.phdr
[i
].p_vaddr
);
1519 dprintf(1, "\t%s (%p)\n", ldso
.name
, ldso
.base
);
1523 libc
.tls_head
= tls_tail
= &app
.tls
;
1524 app
.tls_id
= tls_cnt
= 1;
1527 tls_offset
= app
.tls
.size
1528 + ( -((uintptr_t)app
.tls
.image
+ app
.tls
.size
)
1529 & (app
.tls
.align
-1) );
1531 tls_offset
= app
.tls
.offset
= app
.tls
.size
1532 + ( -((uintptr_t)app
.tls
.image
+ app
.tls
.size
)
1533 & (app
.tls
.align
-1) );
1535 tls_align
= MAXP2(tls_align
, app
.tls
.align
);
1540 makefuncdescs(&app
);
1542 app
.loadmap
= (void *)&app_dummy_loadmap
;
1543 app
.loadmap
->nsegs
= 1;
1544 app
.loadmap
->segs
[0].addr
= (size_t)app
.map
;
1545 app
.loadmap
->segs
[0].p_vaddr
= (size_t)app
.map
1547 app
.loadmap
->segs
[0].p_memsz
= app
.map_len
;
1549 argv
[-3] = (void *)app
.loadmap
;
1552 /* Attach to vdso, if provided by the kernel */
1553 if (search_vec(auxv
, &vdso_base
, AT_SYSINFO_EHDR
) && vdso_base
) {
1554 Ehdr
*ehdr
= (void *)vdso_base
;
1555 Phdr
*phdr
= vdso
.phdr
= (void *)(vdso_base
+ ehdr
->e_phoff
);
1556 vdso
.phnum
= ehdr
->e_phnum
;
1557 vdso
.phentsize
= ehdr
->e_phentsize
;
1558 for (i
=ehdr
->e_phnum
; i
; i
--, phdr
=(void *)((char *)phdr
+ ehdr
->e_phentsize
)) {
1559 if (phdr
->p_type
== PT_DYNAMIC
)
1560 vdso
.dynv
= (void *)(vdso_base
+ phdr
->p_offset
);
1561 if (phdr
->p_type
== PT_LOAD
)
1562 vdso
.base
= (void *)(vdso_base
- phdr
->p_vaddr
+ phdr
->p_offset
);
1565 vdso
.shortname
= "linux-gate.so.1";
1573 /* Initial dso chain consists only of the app. */
1576 /* Donate unused parts of app and library mapping to malloc */
1578 reclaim_gaps(&ldso
);
1580 /* Load preload/needed libraries, add their symbols to the global
1581 * namespace, and perform all remaining relocations. */
1582 if (env_preload
) load_preload(env_preload
);
1586 for (i
=0; app
.dynv
[i
]; i
+=2) {
1587 if (!DT_DEBUG_INDIRECT
&& app
.dynv
[i
]==DT_DEBUG
)
1588 app
.dynv
[i
+1] = (size_t)&debug
;
1589 if (DT_DEBUG_INDIRECT
&& app
.dynv
[i
]==DT_DEBUG_INDIRECT
) {
1590 size_t *ptr
= (size_t *) app
.dynv
[i
+1];
1591 *ptr
= (size_t)&debug
;
1595 /* The main program must be relocated LAST since it may contin
1596 * copy relocations which depend on libraries' relocations. */
1597 reloc_all(app
.next
);
1601 if (libc
.tls_size
> sizeof builtin_tls
|| tls_align
> MIN_TLS_ALIGN
) {
1602 void *initial_tls
= calloc(libc
.tls_size
, 1);
1604 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
1605 argv
[0], libc
.tls_size
);
1608 if (__init_tp(__copy_tls(initial_tls
)) < 0) {
1612 size_t tmp_tls_size
= libc
.tls_size
;
1613 pthread_t self
= __pthread_self();
1614 /* Temporarily set the tls size to the full size of
1615 * builtin_tls so that __copy_tls will use the same layout
1616 * as it did for before. Then check, just to be safe. */
1617 libc
.tls_size
= sizeof builtin_tls
;
1618 if (__copy_tls((void*)builtin_tls
) != self
) a_crash();
1619 libc
.tls_size
= tmp_tls_size
;
1621 static_tls_cnt
= tls_cnt
;
1623 if (ldso_fail
) _exit(127);
1624 if (ldd_mode
) _exit(0);
1626 /* Switch to runtime mode: any further failures in the dynamic
1627 * linker are a reportable failure rather than a fatal startup
1632 debug
.bp
= dl_debug_state
;
1634 debug
.base
= ldso
.base
;
1640 CRTJMP((void *)aux
[AT_ENTRY
], argv
-1);
1644 void *dlopen(const char *file
, int mode
)
1646 struct dso
*volatile p
, *orig_tail
, *next
;
1647 struct tls_module
*orig_tls_tail
;
1648 size_t orig_tls_cnt
, orig_tls_offset
, orig_tls_align
;
1653 if (!file
) return head
;
1655 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE
, &cs
);
1656 pthread_rwlock_wrlock(&lock
);
1660 orig_tls_tail
= tls_tail
;
1661 orig_tls_cnt
= tls_cnt
;
1662 orig_tls_offset
= tls_offset
;
1663 orig_tls_align
= tls_align
;
1665 noload
= mode
& RTLD_NOLOAD
;
1668 if (setjmp(*rtld_fail
)) {
1669 /* Clean up anything new that was (partially) loaded */
1670 if (p
&& p
->deps
) for (i
=0; p
->deps
[i
]; i
++)
1671 if (p
->deps
[i
]->global
< 0)
1672 p
->deps
[i
]->global
= 0;
1673 for (p
=orig_tail
->next
; p
; p
=next
) {
1675 while (p
->td_index
) {
1676 void *tmp
= p
->td_index
->next
;
1681 if (p
->rpath
!= p
->rpath_orig
)
1687 if (!orig_tls_tail
) libc
.tls_head
= 0;
1688 tls_tail
= orig_tls_tail
;
1689 if (tls_tail
) tls_tail
->next
= 0;
1690 tls_cnt
= orig_tls_cnt
;
1691 tls_offset
= orig_tls_offset
;
1692 tls_align
= orig_tls_align
;
1697 } else p
= load_library(file
, head
);
1701 "Library %s is not already loaded" :
1702 "Error loading shared library %s: %m",
1707 /* First load handling */
1710 if (p
->deps
) for (i
=0; p
->deps
[i
]; i
++)
1711 if (!p
->deps
[i
]->global
)
1712 p
->deps
[i
]->global
= -1;
1713 if (!p
->global
) p
->global
= -1;
1715 if (p
->deps
) for (i
=0; p
->deps
[i
]; i
++)
1716 if (p
->deps
[i
]->global
< 0)
1717 p
->deps
[i
]->global
= 0;
1718 if (p
->global
< 0) p
->global
= 0;
1721 if (mode
& RTLD_GLOBAL
) {
1722 if (p
->deps
) for (i
=0; p
->deps
[i
]; i
++)
1723 p
->deps
[i
]->global
= 1;
1733 pthread_rwlock_unlock(&lock
);
1734 if (p
) do_init_fini(orig_tail
);
1735 pthread_setcancelstate(cs
, 0);
1739 __attribute__((__visibility__("hidden")))
1740 int __dl_invalid_handle(void *h
)
1743 for (p
=head
; p
; p
=p
->next
) if (h
==p
) return 0;
1744 error("Invalid library handle %p", (void *)h
);
1748 static void *addr2dso(size_t a
)
1752 if (DL_FDPIC
) for (p
=head
; p
; p
=p
->next
) {
1754 if (a
-(size_t)p
->funcdescs
< i
*sizeof(*p
->funcdescs
))
1757 for (p
=head
; p
; p
=p
->next
) {
1758 if (DL_FDPIC
&& p
->loadmap
) {
1759 for (i
=0; i
<p
->loadmap
->nsegs
; i
++) {
1760 if (a
-p
->loadmap
->segs
[i
].p_vaddr
1761 < p
->loadmap
->segs
[i
].p_memsz
)
1765 if (a
-(size_t)p
->map
< p
->map_len
)
1772 void *__tls_get_addr(tls_mod_off_t
*);
1774 static void *do_dlsym(struct dso
*p
, const char *s
, void *ra
)
1777 uint32_t h
= 0, gh
= 0, *ght
;
1779 if (p
== head
|| p
== RTLD_DEFAULT
|| p
== RTLD_NEXT
) {
1780 if (p
== RTLD_DEFAULT
) {
1782 } else if (p
== RTLD_NEXT
) {
1783 p
= addr2dso((size_t)ra
);
1787 struct symdef def
= find_sym(p
, s
, 0);
1788 if (!def
.sym
) goto failed
;
1789 if ((def
.sym
->st_info
&0xf) == STT_TLS
)
1790 return __tls_get_addr((tls_mod_off_t
[]){def
.dso
->tls_id
, def
.sym
->st_value
});
1791 if (DL_FDPIC
&& (def
.sym
->st_info
&0xf) == STT_FUNC
)
1792 return def
.dso
->funcdescs
+ (def
.sym
- def
.dso
->syms
);
1793 return laddr(def
.dso
, def
.sym
->st_value
);
1795 if (__dl_invalid_handle(p
))
1797 if ((ght
= p
->ghashtab
)) {
1799 sym
= gnu_lookup(gh
, ght
, p
, s
);
1802 sym
= sysv_lookup(s
, h
, p
);
1804 if (sym
&& (sym
->st_info
&0xf) == STT_TLS
)
1805 return __tls_get_addr((tls_mod_off_t
[]){p
->tls_id
, sym
->st_value
});
1806 if (DL_FDPIC
&& sym
&& sym
->st_shndx
&& (sym
->st_info
&0xf) == STT_FUNC
)
1807 return p
->funcdescs
+ (sym
- p
->syms
);
1808 if (sym
&& sym
->st_value
&& (1<<(sym
->st_info
&0xf) & OK_TYPES
))
1809 return laddr(p
, sym
->st_value
);
1810 if (p
->deps
) for (i
=0; p
->deps
[i
]; i
++) {
1811 if ((ght
= p
->deps
[i
]->ghashtab
)) {
1812 if (!gh
) gh
= gnu_hash(s
);
1813 sym
= gnu_lookup(gh
, ght
, p
->deps
[i
], s
);
1815 if (!h
) h
= sysv_hash(s
);
1816 sym
= sysv_lookup(s
, h
, p
->deps
[i
]);
1818 if (sym
&& (sym
->st_info
&0xf) == STT_TLS
)
1819 return __tls_get_addr((tls_mod_off_t
[]){p
->deps
[i
]->tls_id
, sym
->st_value
});
1820 if (DL_FDPIC
&& sym
&& sym
->st_shndx
&& (sym
->st_info
&0xf) == STT_FUNC
)
1821 return p
->deps
[i
]->funcdescs
+ (sym
- p
->deps
[i
]->syms
);
1822 if (sym
&& sym
->st_value
&& (1<<(sym
->st_info
&0xf) & OK_TYPES
))
1823 return laddr(p
->deps
[i
], sym
->st_value
);
1826 error("Symbol not found: %s", s
);
1830 int dladdr(const void *addr
, Dl_info
*info
)
1838 pthread_rwlock_rdlock(&lock
);
1839 p
= addr2dso((size_t)addr
);
1840 pthread_rwlock_unlock(&lock
);
1845 strings
= p
->strings
;
1846 nsym
= count_syms(p
);
1849 size_t idx
= ((size_t)addr
-(size_t)p
->funcdescs
)
1850 / sizeof(*p
->funcdescs
);
1851 if (idx
< nsym
&& (sym
[idx
].st_info
&0xf) == STT_FUNC
) {
1852 best
= p
->funcdescs
+ idx
;
1853 bestsym
= sym
+ idx
;
1857 if (!best
) for (; nsym
; nsym
--, sym
++) {
1859 && (1<<(sym
->st_info
&0xf) & OK_TYPES
)
1860 && (1<<(sym
->st_info
>>4) & OK_BINDS
)) {
1861 void *symaddr
= laddr(p
, sym
->st_value
);
1862 if (symaddr
> addr
|| symaddr
< best
)
1866 if (addr
== symaddr
)
1871 if (!best
) return 0;
1873 if (DL_FDPIC
&& (bestsym
->st_info
&0xf) == STT_FUNC
)
1874 best
= p
->funcdescs
+ (bestsym
- p
->syms
);
1876 info
->dli_fname
= p
->name
;
1877 info
->dli_fbase
= p
->base
;
1878 info
->dli_sname
= strings
+ bestsym
->st_name
;
1879 info
->dli_saddr
= best
;
1884 __attribute__((__visibility__("hidden")))
1885 void *__dlsym(void *restrict p
, const char *restrict s
, void *restrict ra
)
1888 pthread_rwlock_rdlock(&lock
);
1889 res
= do_dlsym(p
, s
, ra
);
1890 pthread_rwlock_unlock(&lock
);
1894 int dl_iterate_phdr(int(*callback
)(struct dl_phdr_info
*info
, size_t size
, void *data
), void *data
)
1896 struct dso
*current
;
1897 struct dl_phdr_info info
;
1899 for(current
= head
; current
;) {
1900 info
.dlpi_addr
= (uintptr_t)current
->base
;
1901 info
.dlpi_name
= current
->name
;
1902 info
.dlpi_phdr
= current
->phdr
;
1903 info
.dlpi_phnum
= current
->phnum
;
1904 info
.dlpi_adds
= gencnt
;
1906 info
.dlpi_tls_modid
= current
->tls_id
;
1907 info
.dlpi_tls_data
= current
->tls
.image
;
1909 ret
= (callback
)(&info
, sizeof (info
), data
);
1911 if (ret
!= 0) break;
1913 pthread_rwlock_rdlock(&lock
);
1914 current
= current
->next
;
1915 pthread_rwlock_unlock(&lock
);
1920 __attribute__((__visibility__("hidden")))
1921 void __dl_vseterr(const char *, va_list);
1923 static void error(const char *fmt
, ...)
1928 vdprintf(2, fmt
, ap
);
1934 __dl_vseterr(fmt
, ap
);