2 #define SYSCALL_NO_TLS 1
20 #include <semaphore.h>
21 #include <sys/membarrier.h>
22 #include "pthread_impl.h"
23 #include "fork_impl.h"
26 static size_t ldso_page_size
;
28 #define PAGE_SIZE ldso_page_size
33 #define malloc __libc_malloc
34 #define calloc __libc_calloc
35 #define realloc __libc_realloc
36 #define free __libc_free
38 static void error_impl(const char *, ...);
39 static void error_noop(const char *, ...);
40 static void (*error
)(const char *, ...) = error_noop
;
42 #define MAXP2(a,b) (-(-(a)&-(b)))
43 #define ALIGN(x,y) ((x)+(y)-1 & -(y))
45 #define container_of(p,t,m) ((t*)((char *)(p)-offsetof(t,m)))
46 #define countof(a) ((sizeof (a))/(sizeof (a)[0]))
58 struct td_index
*next
;
63 struct fdpic_loadmap
*loadmap
;
69 struct dso
*next
, *prev
;
79 struct dso
*syms_next
, *lazy_next
;
80 size_t *lazy
, lazy_cnt
;
91 struct dso
**deps
, *needed_by
;
94 pthread_t ctor_visitor
;
95 char *rpath_orig
, *rpath
;
96 struct tls_module tls
;
98 size_t relro_start
, relro_end
;
100 unsigned char *new_tls
;
101 struct td_index
*td_index
;
102 struct dso
*fini_next
;
107 struct fdpic_loadmap
*loadmap
;
122 typedef void (*stage3_func
)(size_t *, size_t *);
124 static struct builtin_tls
{
129 #define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
131 #define ADDEND_LIMIT 4096
132 static size_t *saved_addends
, *apply_addends_to
;
134 static struct dso ldso
;
135 static struct dso
*head
, *tail
, *fini_head
, *syms_tail
, *lazy_head
;
136 static char *env_path
, *sys_path
;
137 static unsigned long long gencnt
;
140 static int ldso_fail
;
142 static int shutting_down
;
143 static jmp_buf *rtld_fail
;
144 static pthread_rwlock_t lock
;
145 static struct debug debug
;
146 static struct tls_module
*tls_tail
;
147 static size_t tls_cnt
, tls_offset
, tls_align
= MIN_TLS_ALIGN
;
148 static size_t static_tls_cnt
;
149 static pthread_mutex_t init_fini_lock
;
150 static pthread_cond_t ctor_cond
;
151 static struct dso
*builtin_deps
[2];
152 static struct dso
*const no_deps
[1];
153 static struct dso
*builtin_ctor_queue
[4];
154 static struct dso
**main_ctor_queue
;
155 static struct fdpic_loadmap
*app_loadmap
;
156 static struct fdpic_dummy_loadmap app_dummy_loadmap
;
158 struct debug
*_dl_debug_addr
= &debug
;
160 extern weak hidden
char __ehdr_start
[];
162 extern hidden
int __malloc_replaced
;
164 hidden
void (*const __init_array_start
)(void)=0, (*const __fini_array_start
)(void)=0;
166 extern hidden
void (*const __init_array_end
)(void), (*const __fini_array_end
)(void);
168 weak_alias(__init_array_start
, __init_array_end
);
169 weak_alias(__fini_array_start
, __fini_array_end
);
171 static int dl_strcmp(const char *l
, const char *r
)
173 for (; *l
==*r
&& *l
; l
++, r
++);
174 return *(unsigned char *)l
- *(unsigned char *)r
;
176 #define strcmp(l,r) dl_strcmp(l,r)
178 /* Compute load address for a virtual address in a given dso. */
180 static void *laddr(const struct dso
*p
, size_t v
)
183 if (!p
->loadmap
) return p
->base
+ v
;
184 for (j
=0; v
-p
->loadmap
->segs
[j
].p_vaddr
>= p
->loadmap
->segs
[j
].p_memsz
; j
++);
185 return (void *)(v
- p
->loadmap
->segs
[j
].p_vaddr
+ p
->loadmap
->segs
[j
].addr
);
187 static void *laddr_pg(const struct dso
*p
, size_t v
)
190 size_t pgsz
= PAGE_SIZE
;
191 if (!p
->loadmap
) return p
->base
+ v
;
193 size_t a
= p
->loadmap
->segs
[j
].p_vaddr
;
194 size_t b
= a
+ p
->loadmap
->segs
[j
].p_memsz
;
200 return (void *)(v
- p
->loadmap
->segs
[j
].p_vaddr
+ p
->loadmap
->segs
[j
].addr
);
202 static void (*fdbarrier(void *p
))()
205 __asm__("" : "=r"(fd
) : "0"(p
));
208 #define fpaddr(p, v) fdbarrier((&(struct funcdesc){ \
209 laddr(p, v), (p)->got }))
211 #define laddr(p, v) (void *)((p)->base + (v))
212 #define laddr_pg(p, v) laddr(p, v)
213 #define fpaddr(p, v) ((void (*)())laddr(p, v))
216 static void decode_vec(size_t *v
, size_t *a
, size_t cnt
)
219 for (i
=0; i
<cnt
; i
++) a
[i
] = 0;
220 for (; v
[0]; v
+=2) if (v
[0]-1<cnt
-1) {
221 if (v
[0] < 8*sizeof(long))
227 static int search_vec(size_t *v
, size_t *r
, size_t key
)
229 for (; v
[0]!=key
; v
+=2)
235 static uint32_t sysv_hash(const char *s0
)
237 const unsigned char *s
= (void *)s0
;
243 return h
& 0xfffffff;
246 static uint32_t gnu_hash(const char *s0
)
248 const unsigned char *s
= (void *)s0
;
249 uint_fast32_t h
= 5381;
255 static Sym
*sysv_lookup(const char *s
, uint32_t h
, struct dso
*dso
)
258 Sym
*syms
= dso
->syms
;
259 Elf_Symndx
*hashtab
= dso
->hashtab
;
260 char *strings
= dso
->strings
;
261 for (i
=hashtab
[2+h
%hashtab
[0]]; i
; i
=hashtab
[2+hashtab
[0]+i
]) {
262 if ((!dso
->versym
|| dso
->versym
[i
] >= 0)
263 && (!strcmp(s
, strings
+syms
[i
].st_name
)))
269 static Sym
*gnu_lookup(uint32_t h1
, uint32_t *hashtab
, struct dso
*dso
, const char *s
)
271 uint32_t nbuckets
= hashtab
[0];
272 uint32_t *buckets
= hashtab
+ 4 + hashtab
[2]*(sizeof(size_t)/4);
273 uint32_t i
= buckets
[h1
% nbuckets
];
277 uint32_t *hashval
= buckets
+ nbuckets
+ (i
- hashtab
[1]);
279 for (h1
|= 1; ; i
++) {
280 uint32_t h2
= *hashval
++;
281 if ((h1
== (h2
|1)) && (!dso
->versym
|| dso
->versym
[i
] >= 0)
282 && !strcmp(s
, dso
->strings
+ dso
->syms
[i
].st_name
))
290 static Sym
*gnu_lookup_filtered(uint32_t h1
, uint32_t *hashtab
, struct dso
*dso
, const char *s
, uint32_t fofs
, size_t fmask
)
292 const size_t *bloomwords
= (const void *)(hashtab
+4);
293 size_t f
= bloomwords
[fofs
& (hashtab
[2]-1)];
294 if (!(f
& fmask
)) return 0;
296 f
>>= (h1
>> hashtab
[3]) % (8 * sizeof f
);
297 if (!(f
& 1)) return 0;
299 return gnu_lookup(h1
, hashtab
, dso
, s
);
302 #define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON | 1<<STT_TLS)
303 #define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
305 #ifndef ARCH_SYM_REJECT_UND
306 #define ARCH_SYM_REJECT_UND(s) 0
309 #if defined(__GNUC__)
310 __attribute__((always_inline
))
312 static inline struct symdef
find_sym2(struct dso
*dso
, const char *s
, int need_def
, int use_deps
)
314 uint32_t h
= 0, gh
= gnu_hash(s
), gho
= gh
/ (8*sizeof(size_t)), *ght
;
315 size_t ghm
= 1ul << gh
% (8*sizeof(size_t));
316 struct symdef def
= {0};
317 struct dso
**deps
= use_deps
? dso
->deps
: 0;
318 for (; dso
; dso
=use_deps
? *deps
++ : dso
->syms_next
) {
320 if ((ght
= dso
->ghashtab
)) {
321 sym
= gnu_lookup_filtered(gh
, ght
, dso
, s
, gho
, ghm
);
323 if (!h
) h
= sysv_hash(s
);
324 sym
= sysv_lookup(s
, h
, dso
);
328 if (need_def
|| (sym
->st_info
&0xf) == STT_TLS
329 || ARCH_SYM_REJECT_UND(sym
))
332 if ((sym
->st_info
&0xf) != STT_TLS
)
334 if (!(1<<(sym
->st_info
&0xf) & OK_TYPES
)) continue;
335 if (!(1<<(sym
->st_info
>>4) & OK_BINDS
)) continue;
343 static struct symdef
find_sym(struct dso
*dso
, const char *s
, int need_def
)
345 return find_sym2(dso
, s
, need_def
, 0);
348 static struct symdef
get_lfs64(const char *name
)
351 static const char lfs64_list
[] =
352 "aio_cancel\0aio_error\0aio_fsync\0aio_read\0aio_return\0"
353 "aio_suspend\0aio_write\0alphasort\0creat\0fallocate\0"
354 "fgetpos\0fopen\0freopen\0fseeko\0fsetpos\0fstat\0"
355 "fstatat\0fstatfs\0fstatvfs\0ftello\0ftruncate\0ftw\0"
356 "getdents\0getrlimit\0glob\0globfree\0lio_listio\0"
357 "lockf\0lseek\0lstat\0mkostemp\0mkostemps\0mkstemp\0"
358 "mkstemps\0mmap\0nftw\0open\0openat\0posix_fadvise\0"
359 "posix_fallocate\0pread\0preadv\0prlimit\0pwrite\0"
360 "pwritev\0readdir\0scandir\0sendfile\0setrlimit\0"
361 "stat\0statfs\0statvfs\0tmpfile\0truncate\0versionsort\0"
362 "__fxstat\0__fxstatat\0__lxstat\0__xstat\0";
365 for (l
=0; name
[l
]; l
++) {
366 if (l
>= sizeof buf
) goto nomatch
;
369 if (!strcmp(name
, "readdir64_r"))
370 return find_sym(&ldso
, "readdir_r", 1);
371 if (l
<2 || name
[l
-2]!='6' || name
[l
-1]!='4')
374 for (p
=lfs64_list
; *p
; p
++) {
375 if (!strcmp(buf
, p
)) return find_sym(&ldso
, buf
, 1);
379 return (struct symdef
){ 0 };
382 static void do_relocs(struct dso
*dso
, size_t *rel
, size_t rel_size
, size_t stride
)
384 unsigned char *base
= dso
->base
;
385 Sym
*syms
= dso
->syms
;
386 char *strings
= dso
->strings
;
397 int skip_relative
= 0, reuse_addends
= 0, save_slot
= 0;
400 /* Only ldso's REL table needs addend saving/reuse. */
401 if (rel
== apply_addends_to
)
406 for (; rel_size
; rel
+=stride
, rel_size
-=stride
*sizeof(size_t)) {
407 if (skip_relative
&& IS_RELATIVE(rel
[1], dso
->syms
)) continue;
408 type
= R_TYPE(rel
[1]);
409 if (type
== REL_NONE
) continue;
410 reloc_addr
= laddr(dso
, rel
[0]);
414 } else if (type
==REL_GOT
|| type
==REL_PLT
|| type
==REL_COPY
) {
416 } else if (reuse_addends
) {
417 /* Save original addend in stage 2 where the dso
418 * chain consists of just ldso; otherwise read back
419 * saved addend since the inline one was clobbered. */
421 saved_addends
[save_slot
] = *reloc_addr
;
422 addend
= saved_addends
[save_slot
++];
424 addend
= *reloc_addr
;
427 sym_index
= R_SYM(rel
[1]);
429 sym
= syms
+ sym_index
;
430 name
= strings
+ sym
->st_name
;
431 ctx
= type
==REL_COPY
? head
->syms_next
: head
;
432 def
= (sym
->st_info
>>4) == STB_LOCAL
433 ? (struct symdef
){ .dso
= dso
, .sym
= sym
}
434 : find_sym(ctx
, name
, type
==REL_PLT
);
435 if (!def
.sym
) def
= get_lfs64(name
);
436 if (!def
.sym
&& (sym
->st_shndx
!= SHN_UNDEF
437 || sym
->st_info
>>4 != STB_WEAK
)) {
438 if (dso
->lazy
&& (type
==REL_PLT
|| type
==REL_GOT
)) {
439 dso
->lazy
[3*dso
->lazy_cnt
+0] = rel
[0];
440 dso
->lazy
[3*dso
->lazy_cnt
+1] = rel
[1];
441 dso
->lazy
[3*dso
->lazy_cnt
+2] = addend
;
445 error("Error relocating %s: %s: symbol not found",
447 if (runtime
) longjmp(*rtld_fail
, 1);
456 sym_val
= def
.sym
? (size_t)laddr(def
.dso
, def
.sym
->st_value
) : 0;
457 tls_val
= def
.sym
? def
.sym
->st_value
: 0;
459 if ((type
== REL_TPOFF
|| type
== REL_TPOFF_NEG
)
460 && def
.dso
->tls_id
> static_tls_cnt
) {
461 error("Error relocating %s: %s: initial-exec TLS "
462 "resolves to dynamic definition in %s",
463 dso
->name
, name
, def
.dso
->name
);
464 longjmp(*rtld_fail
, 1);
469 addend
-= (size_t)reloc_addr
;
473 *reloc_addr
= sym_val
+ addend
;
476 memcpy(reloc_addr
, &(size_t){sym_val
+ addend
}, sizeof(size_t));
479 *reloc_addr
= (size_t)base
+ addend
;
482 if (sym
) *reloc_addr
= sym_val
+ addend
;
483 else *reloc_addr
= (size_t)base
+ addend
;
486 memcpy(reloc_addr
, (void *)sym_val
, sym
->st_size
);
489 *(uint32_t *)reloc_addr
= sym_val
+ addend
490 - (size_t)reloc_addr
;
493 *reloc_addr
= def
.sym
? (size_t)(def
.dso
->funcdescs
494 + (def
.sym
- def
.dso
->syms
)) : 0;
496 case REL_FUNCDESC_VAL
:
497 if ((sym
->st_info
&0xf) == STT_SECTION
) *reloc_addr
+= sym_val
;
498 else *reloc_addr
= sym_val
;
499 reloc_addr
[1] = def
.sym
? (size_t)def
.dso
->got
: 0;
502 *reloc_addr
= def
.dso
->tls_id
;
505 *reloc_addr
= tls_val
+ addend
- DTP_OFFSET
;
509 *reloc_addr
= tls_val
+ def
.dso
->tls
.offset
+ TPOFF_K
+ addend
;
513 *reloc_addr
= tls_val
- def
.dso
->tls
.offset
+ addend
;
516 *reloc_addr
= def
.dso
->tls
.offset
- tls_val
+ addend
;
520 if (stride
<3) addend
= reloc_addr
[!TLSDESC_BACKWARDS
];
521 if (def
.dso
->tls_id
> static_tls_cnt
) {
522 struct td_index
*new = malloc(sizeof *new);
525 "Error relocating %s: cannot allocate TLSDESC for %s",
526 dso
->name
, sym
? name
: "(local)" );
527 longjmp(*rtld_fail
, 1);
529 new->next
= dso
->td_index
;
531 new->args
[0] = def
.dso
->tls_id
;
532 new->args
[1] = tls_val
+ addend
- DTP_OFFSET
;
533 reloc_addr
[0] = (size_t)__tlsdesc_dynamic
;
534 reloc_addr
[1] = (size_t)new;
536 reloc_addr
[0] = (size_t)__tlsdesc_static
;
538 reloc_addr
[1] = tls_val
+ def
.dso
->tls
.offset
541 reloc_addr
[1] = tls_val
- def
.dso
->tls
.offset
545 /* Some archs (32-bit ARM at least) invert the order of
546 * the descriptor members. Fix them up here. */
547 if (TLSDESC_BACKWARDS
) {
548 size_t tmp
= reloc_addr
[0];
549 reloc_addr
[0] = reloc_addr
[1];
554 error("Error relocating %s: unsupported relocation type %d",
556 if (runtime
) longjmp(*rtld_fail
, 1);
562 static void do_relr_relocs(struct dso
*dso
, size_t *relr
, size_t relr_size
)
564 if (dso
== &ldso
) return; /* self-relocation was done in _dlstart */
565 unsigned char *base
= dso
->base
;
567 for (; relr_size
; relr
++, relr_size
-=sizeof(size_t))
568 if ((relr
[0]&1) == 0) {
569 reloc_addr
= laddr(dso
, relr
[0]);
570 *reloc_addr
++ += (size_t)base
;
573 for (size_t bitmap
=relr
[0]; (bitmap
>>=1); i
++)
575 reloc_addr
[i
] += (size_t)base
;
576 reloc_addr
+= 8*sizeof(size_t)-1;
580 static void redo_lazy_relocs()
582 struct dso
*p
= lazy_head
, *next
;
586 size_t size
= p
->lazy_cnt
*3*sizeof(size_t);
588 do_relocs(p
, p
->lazy
, size
, 3);
590 p
->lazy_next
= lazy_head
;
600 /* A huge hack: to make up for the wastefulness of shared libraries
601 * needing at least a page of dirty memory even if they have no global
602 * data, we reclaim the gaps at the beginning and end of writable maps
603 * and "donate" them to the heap. */
605 static void reclaim(struct dso
*dso
, size_t start
, size_t end
)
607 if (start
>= dso
->relro_start
&& start
< dso
->relro_end
) start
= dso
->relro_end
;
608 if (end
>= dso
->relro_start
&& end
< dso
->relro_end
) end
= dso
->relro_start
;
609 if (start
>= end
) return;
610 char *base
= laddr_pg(dso
, start
);
611 __malloc_donate(base
, base
+(end
-start
));
614 static void reclaim_gaps(struct dso
*dso
)
616 Phdr
*ph
= dso
->phdr
;
617 size_t phcnt
= dso
->phnum
;
619 for (; phcnt
--; ph
=(void *)((char *)ph
+dso
->phentsize
)) {
620 if (ph
->p_type
!=PT_LOAD
) continue;
621 if ((ph
->p_flags
&(PF_R
|PF_W
))!=(PF_R
|PF_W
)) continue;
622 reclaim(dso
, ph
->p_vaddr
& -PAGE_SIZE
, ph
->p_vaddr
);
623 reclaim(dso
, ph
->p_vaddr
+ph
->p_memsz
,
624 ph
->p_vaddr
+ph
->p_memsz
+PAGE_SIZE
-1 & -PAGE_SIZE
);
628 static ssize_t
read_loop(int fd
, void *p
, size_t n
)
630 for (size_t i
=0; i
<n
; ) {
631 ssize_t l
= read(fd
, (char *)p
+i
, n
-i
);
633 if (errno
==EINTR
) continue;
642 static void *mmap_fixed(void *p
, size_t n
, int prot
, int flags
, int fd
, off_t off
)
644 static int no_map_fixed
;
648 q
= mmap(p
, n
, prot
, flags
|MAP_FIXED
, fd
, off
);
649 if (!DL_NOMMU_SUPPORT
|| q
!= MAP_FAILED
|| errno
!= EINVAL
)
653 /* Fallbacks for MAP_FIXED failure on NOMMU kernels. */
654 if (flags
& MAP_ANONYMOUS
) {
659 if (lseek(fd
, off
, SEEK_SET
) < 0) return MAP_FAILED
;
660 for (q
=p
; n
; q
+=r
, off
+=r
, n
-=r
) {
662 if (r
< 0 && errno
!= EINTR
) return MAP_FAILED
;
671 static void unmap_library(struct dso
*dso
)
675 for (i
=0; i
<dso
->loadmap
->nsegs
; i
++) {
676 if (!dso
->loadmap
->segs
[i
].p_memsz
)
678 munmap((void *)dso
->loadmap
->segs
[i
].addr
,
679 dso
->loadmap
->segs
[i
].p_memsz
);
682 } else if (dso
->map
&& dso
->map_len
) {
683 munmap(dso
->map
, dso
->map_len
);
687 static void *map_library(int fd
, struct dso
*dso
)
689 Ehdr buf
[(896+sizeof(Ehdr
))/sizeof(Ehdr
)];
690 void *allocated_buf
=0;
692 size_t addr_min
=SIZE_MAX
, addr_max
=0, map_len
;
693 size_t this_min
, this_max
;
699 unsigned char *map
=MAP_FAILED
, *base
;
704 ssize_t l
= read(fd
, buf
, sizeof buf
);
707 if (l
<sizeof *eh
|| (eh
->e_type
!= ET_DYN
&& eh
->e_type
!= ET_EXEC
))
709 phsize
= eh
->e_phentsize
* eh
->e_phnum
;
710 if (phsize
> sizeof buf
- sizeof *eh
) {
711 allocated_buf
= malloc(phsize
);
712 if (!allocated_buf
) return 0;
713 l
= pread(fd
, allocated_buf
, phsize
, eh
->e_phoff
);
714 if (l
< 0) goto error
;
715 if (l
!= phsize
) goto noexec
;
716 ph
= ph0
= allocated_buf
;
717 } else if (eh
->e_phoff
+ phsize
> l
) {
718 l
= pread(fd
, buf
+1, phsize
, eh
->e_phoff
);
719 if (l
< 0) goto error
;
720 if (l
!= phsize
) goto noexec
;
721 ph
= ph0
= (void *)(buf
+ 1);
723 ph
= ph0
= (void *)((char *)buf
+ eh
->e_phoff
);
725 for (i
=eh
->e_phnum
; i
; i
--, ph
=(void *)((char *)ph
+eh
->e_phentsize
)) {
726 if (ph
->p_type
== PT_DYNAMIC
) {
728 } else if (ph
->p_type
== PT_TLS
) {
729 tls_image
= ph
->p_vaddr
;
730 dso
->tls
.align
= ph
->p_align
;
731 dso
->tls
.len
= ph
->p_filesz
;
732 dso
->tls
.size
= ph
->p_memsz
;
733 } else if (ph
->p_type
== PT_GNU_RELRO
) {
734 dso
->relro_start
= ph
->p_vaddr
& -PAGE_SIZE
;
735 dso
->relro_end
= (ph
->p_vaddr
+ ph
->p_memsz
) & -PAGE_SIZE
;
736 } else if (ph
->p_type
== PT_GNU_STACK
) {
737 if (!runtime
&& ph
->p_memsz
> __default_stacksize
) {
738 __default_stacksize
=
739 ph
->p_memsz
< DEFAULT_STACK_MAX
?
740 ph
->p_memsz
: DEFAULT_STACK_MAX
;
743 if (ph
->p_type
!= PT_LOAD
) continue;
745 if (ph
->p_vaddr
< addr_min
) {
746 addr_min
= ph
->p_vaddr
;
747 off_start
= ph
->p_offset
;
748 prot
= (((ph
->p_flags
&PF_R
) ? PROT_READ
: 0) |
749 ((ph
->p_flags
&PF_W
) ? PROT_WRITE
: 0) |
750 ((ph
->p_flags
&PF_X
) ? PROT_EXEC
: 0));
752 if (ph
->p_vaddr
+ph
->p_memsz
> addr_max
) {
753 addr_max
= ph
->p_vaddr
+ph
->p_memsz
;
756 if (!dyn
) goto noexec
;
757 if (DL_FDPIC
&& !(eh
->e_flags
& FDPIC_CONSTDISP_FLAG
)) {
758 dso
->loadmap
= calloc(1, sizeof *dso
->loadmap
759 + nsegs
* sizeof *dso
->loadmap
->segs
);
760 if (!dso
->loadmap
) goto error
;
761 dso
->loadmap
->nsegs
= nsegs
;
762 for (ph
=ph0
, i
=0; i
<nsegs
; ph
=(void *)((char *)ph
+eh
->e_phentsize
)) {
763 if (ph
->p_type
!= PT_LOAD
) continue;
764 prot
= (((ph
->p_flags
&PF_R
) ? PROT_READ
: 0) |
765 ((ph
->p_flags
&PF_W
) ? PROT_WRITE
: 0) |
766 ((ph
->p_flags
&PF_X
) ? PROT_EXEC
: 0));
767 map
= mmap(0, ph
->p_memsz
+ (ph
->p_vaddr
& PAGE_SIZE
-1),
769 fd
, ph
->p_offset
& -PAGE_SIZE
);
770 if (map
== MAP_FAILED
) {
774 dso
->loadmap
->segs
[i
].addr
= (size_t)map
+
775 (ph
->p_vaddr
& PAGE_SIZE
-1);
776 dso
->loadmap
->segs
[i
].p_vaddr
= ph
->p_vaddr
;
777 dso
->loadmap
->segs
[i
].p_memsz
= ph
->p_memsz
;
779 if (prot
& PROT_WRITE
) {
780 size_t brk
= (ph
->p_vaddr
& PAGE_SIZE
-1)
782 size_t pgbrk
= brk
+ PAGE_SIZE
-1 & -PAGE_SIZE
;
783 size_t pgend
= brk
+ ph
->p_memsz
- ph
->p_filesz
784 + PAGE_SIZE
-1 & -PAGE_SIZE
;
785 if (pgend
> pgbrk
&& mmap_fixed(map
+pgbrk
,
787 MAP_PRIVATE
|MAP_FIXED
|MAP_ANONYMOUS
,
788 -1, off_start
) == MAP_FAILED
)
790 memset(map
+ brk
, 0, pgbrk
-brk
);
793 map
= (void *)dso
->loadmap
->segs
[0].addr
;
797 addr_max
+= PAGE_SIZE
-1;
798 addr_max
&= -PAGE_SIZE
;
799 addr_min
&= -PAGE_SIZE
;
800 off_start
&= -PAGE_SIZE
;
801 map_len
= addr_max
- addr_min
+ off_start
;
802 /* The first time, we map too much, possibly even more than
803 * the length of the file. This is okay because we will not
804 * use the invalid part; we just need to reserve the right
805 * amount of virtual address space to map over later. */
806 map
= DL_NOMMU_SUPPORT
807 ? mmap((void *)addr_min
, map_len
, PROT_READ
|PROT_WRITE
|PROT_EXEC
,
808 MAP_PRIVATE
|MAP_ANONYMOUS
, -1, 0)
809 : mmap((void *)addr_min
, map_len
, prot
,
810 MAP_PRIVATE
, fd
, off_start
);
811 if (map
==MAP_FAILED
) goto error
;
813 dso
->map_len
= map_len
;
814 /* If the loaded file is not relocatable and the requested address is
815 * not available, then the load operation must fail. */
816 if (eh
->e_type
!= ET_DYN
&& addr_min
&& map
!=(void *)addr_min
) {
820 base
= map
- addr_min
;
823 for (ph
=ph0
, i
=eh
->e_phnum
; i
; i
--, ph
=(void *)((char *)ph
+eh
->e_phentsize
)) {
824 if (ph
->p_type
!= PT_LOAD
) continue;
825 /* Check if the programs headers are in this load segment, and
826 * if so, record the address for use by dl_iterate_phdr. */
827 if (!dso
->phdr
&& eh
->e_phoff
>= ph
->p_offset
828 && eh
->e_phoff
+phsize
<= ph
->p_offset
+ph
->p_filesz
) {
829 dso
->phdr
= (void *)(base
+ ph
->p_vaddr
830 + (eh
->e_phoff
-ph
->p_offset
));
831 dso
->phnum
= eh
->e_phnum
;
832 dso
->phentsize
= eh
->e_phentsize
;
834 this_min
= ph
->p_vaddr
& -PAGE_SIZE
;
835 this_max
= ph
->p_vaddr
+ph
->p_memsz
+PAGE_SIZE
-1 & -PAGE_SIZE
;
836 off_start
= ph
->p_offset
& -PAGE_SIZE
;
837 prot
= (((ph
->p_flags
&PF_R
) ? PROT_READ
: 0) |
838 ((ph
->p_flags
&PF_W
) ? PROT_WRITE
: 0) |
839 ((ph
->p_flags
&PF_X
) ? PROT_EXEC
: 0));
840 /* Reuse the existing mapping for the lowest-address LOAD */
841 if ((ph
->p_vaddr
& -PAGE_SIZE
) != addr_min
|| DL_NOMMU_SUPPORT
)
842 if (mmap_fixed(base
+this_min
, this_max
-this_min
, prot
, MAP_PRIVATE
|MAP_FIXED
, fd
, off_start
) == MAP_FAILED
)
844 if (ph
->p_memsz
> ph
->p_filesz
&& (ph
->p_flags
&PF_W
)) {
845 size_t brk
= (size_t)base
+ph
->p_vaddr
+ph
->p_filesz
;
846 size_t pgbrk
= brk
+PAGE_SIZE
-1 & -PAGE_SIZE
;
847 memset((void *)brk
, 0, pgbrk
-brk
& PAGE_SIZE
-1);
848 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
)
852 for (i
=0; ((size_t *)(base
+dyn
))[i
]; i
+=2)
853 if (((size_t *)(base
+dyn
))[i
]==DT_TEXTREL
) {
854 if (mprotect(map
, map_len
, PROT_READ
|PROT_WRITE
|PROT_EXEC
)
861 dso
->dynv
= laddr(dso
, dyn
);
862 if (dso
->tls
.size
) dso
->tls
.image
= laddr(dso
, tls_image
);
868 if (map
!=MAP_FAILED
) unmap_library(dso
);
873 static int path_open(const char *name
, const char *s
, char *buf
, size_t buf_size
)
878 s
+= strspn(s
, ":\n");
879 l
= strcspn(s
, ":\n");
880 if (l
-1 >= INT_MAX
) return -1;
881 if (snprintf(buf
, buf_size
, "%.*s/%s", (int)l
, s
, name
) < buf_size
) {
882 if ((fd
= open(buf
, O_RDONLY
|O_CLOEXEC
))>=0) return fd
;
890 /* Any negative value but -1 will inhibit
891 * futher path search. */
899 static int fixup_rpath(struct dso
*p
, char *buf
, size_t buf_size
)
902 const char *s
, *t
, *origin
;
904 if (p
->rpath
|| !p
->rpath_orig
) return 0;
905 if (!strchr(p
->rpath_orig
, '$')) {
906 p
->rpath
= p
->rpath_orig
;
911 while ((t
=strchr(s
, '$'))) {
912 if (strncmp(t
, "$ORIGIN", 7) && strncmp(t
, "${ORIGIN}", 9))
917 if (n
> SSIZE_MAX
/PATH_MAX
) return 0;
919 if (p
->kernel_mapped
) {
920 /* $ORIGIN searches cannot be performed for the main program
921 * when it is suid/sgid/AT_SECURE. This is because the
922 * pathname is under the control of the caller of execve.
923 * For libraries, however, $ORIGIN can be processed safely
924 * since the library's pathname came from a trusted source
925 * (either system paths or a call to dlopen). */
928 l
= readlink("/proc/self/exe", buf
, buf_size
);
929 if (l
== -1) switch (errno
) {
944 t
= strrchr(origin
, '/');
948 /* Normally p->name will always be an absolute or relative
949 * pathname containing at least one '/' character, but in the
950 * case where ldso was invoked as a command to execute a
951 * program in the working directory, app.name may not. Fix. */
955 /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
956 if (libc
.secure
&& *origin
!= '/')
958 p
->rpath
= malloc(strlen(p
->rpath_orig
) + n
*l
+ 1);
959 if (!p
->rpath
) return -1;
963 while ((t
=strchr(s
, '$'))) {
966 memcpy(d
, origin
, l
);
968 /* It was determined previously that the '$' is followed
969 * either by "ORIGIN" or "{ORIGIN}". */
970 s
= t
+ 7 + 2*(t
[1]=='{');
976 static void decode_dyn(struct dso
*p
)
979 decode_vec(p
->dynv
, dyn
, DYN_CNT
);
980 p
->syms
= laddr(p
, dyn
[DT_SYMTAB
]);
981 p
->strings
= laddr(p
, dyn
[DT_STRTAB
]);
982 if (dyn
[0]&(1<<DT_HASH
))
983 p
->hashtab
= laddr(p
, dyn
[DT_HASH
]);
984 if (dyn
[0]&(1<<DT_RPATH
))
985 p
->rpath_orig
= p
->strings
+ dyn
[DT_RPATH
];
986 if (dyn
[0]&(1<<DT_RUNPATH
))
987 p
->rpath_orig
= p
->strings
+ dyn
[DT_RUNPATH
];
988 if (dyn
[0]&(1<<DT_PLTGOT
))
989 p
->got
= laddr(p
, dyn
[DT_PLTGOT
]);
990 if (search_vec(p
->dynv
, dyn
, DT_GNU_HASH
))
991 p
->ghashtab
= laddr(p
, *dyn
);
992 if (search_vec(p
->dynv
, dyn
, DT_VERSYM
))
993 p
->versym
= laddr(p
, *dyn
);
996 static size_t count_syms(struct dso
*p
)
998 if (p
->hashtab
) return p
->hashtab
[1];
1001 uint32_t *buckets
= p
->ghashtab
+ 4 + (p
->ghashtab
[2]*sizeof(size_t)/4);
1003 for (i
= nsym
= 0; i
< p
->ghashtab
[0]; i
++) {
1004 if (buckets
[i
] > nsym
)
1008 hashval
= buckets
+ p
->ghashtab
[0] + (nsym
- p
->ghashtab
[1]);
1010 while (!(*hashval
++ & 1));
1015 static void *dl_mmap(size_t n
)
1018 int prot
= PROT_READ
|PROT_WRITE
, flags
= MAP_ANONYMOUS
|MAP_PRIVATE
;
1020 p
= (void *)__syscall(SYS_mmap2
, 0, n
, prot
, flags
, -1, 0);
1022 p
= (void *)__syscall(SYS_mmap
, 0, n
, prot
, flags
, -1, 0);
1024 return (unsigned long)p
> -4096UL ? 0 : p
;
1027 static void makefuncdescs(struct dso
*p
)
1029 static int self_done
;
1030 size_t nsym
= count_syms(p
);
1031 size_t i
, size
= nsym
* sizeof(*p
->funcdescs
);
1034 p
->funcdescs
= dl_mmap(size
);
1037 p
->funcdescs
= malloc(size
);
1039 if (!p
->funcdescs
) {
1040 if (!runtime
) a_crash();
1041 error("Error allocating function descriptors for %s", p
->name
);
1042 longjmp(*rtld_fail
, 1);
1044 for (i
=0; i
<nsym
; i
++) {
1045 if ((p
->syms
[i
].st_info
&0xf)==STT_FUNC
&& p
->syms
[i
].st_shndx
) {
1046 p
->funcdescs
[i
].addr
= laddr(p
, p
->syms
[i
].st_value
);
1047 p
->funcdescs
[i
].got
= p
->got
;
1049 p
->funcdescs
[i
].addr
= 0;
1050 p
->funcdescs
[i
].got
= 0;
1055 static struct dso
*load_library(const char *name
, struct dso
*needed_by
)
1057 char buf
[2*NAME_MAX
+2];
1058 const char *pathname
;
1060 struct dso
*p
, temp_dso
= {0};
1072 /* Catch and block attempts to reload the implementation itself */
1073 if (name
[0]=='l' && name
[1]=='i' && name
[2]=='b') {
1074 static const char reserved
[] =
1075 "c.pthread.rt.m.dl.util.xnet.";
1076 const char *rp
, *next
;
1077 for (rp
=reserved
; *rp
; rp
=next
) {
1078 next
= strchr(rp
, '.') + 1;
1079 if (strncmp(name
+3, rp
, next
-rp
) == 0)
1084 /* Track which names have been resolved
1085 * and only report each one once. */
1086 static unsigned reported
;
1087 unsigned mask
= 1U<<(rp
-reserved
);
1088 if (!(reported
& mask
)) {
1090 dprintf(1, "\t%s => %s (%p)\n",
1098 if (!strcmp(name
, ldso
.name
)) is_self
= 1;
1107 if (strchr(name
, '/')) {
1109 fd
= open(name
, O_RDONLY
|O_CLOEXEC
);
1111 /* Search for the name to see if it's already loaded */
1112 for (p
=head
->next
; p
; p
=p
->next
) {
1113 if (p
->shortname
&& !strcmp(p
->shortname
, name
)) {
1117 if (strlen(name
) > NAME_MAX
) return 0;
1119 if (env_path
) fd
= path_open(name
, env_path
, buf
, sizeof buf
);
1120 for (p
=needed_by
; fd
== -1 && p
; p
=p
->needed_by
) {
1121 if (fixup_rpath(p
, buf
, sizeof buf
) < 0)
1122 fd
= -2; /* Inhibit further search. */
1124 fd
= path_open(name
, p
->rpath
, buf
, sizeof buf
);
1130 if (ldso
.name
[0]=='/') {
1132 for (s
=t
=z
=ldso
.name
; *s
; s
++)
1133 if (*s
=='/') z
=t
, t
=s
;
1134 prefix_len
= z
-ldso
.name
;
1135 if (prefix_len
< PATH_MAX
)
1142 char etc_ldso_path
[prefix_len
+ 1
1143 + sizeof "/etc/ld-musl-" LDSO_ARCH
".path"];
1144 snprintf(etc_ldso_path
, sizeof etc_ldso_path
,
1145 "%.*s/etc/ld-musl-" LDSO_ARCH
".path",
1146 (int)prefix_len
, prefix
);
1147 fd
= open(etc_ldso_path
, O_RDONLY
|O_CLOEXEC
);
1150 if (!fstat(fd
, &st
)) n
= st
.st_size
;
1151 if ((sys_path
= malloc(n
+1)))
1153 if (!sys_path
|| read_loop(fd
, sys_path
, n
)<0) {
1158 } else if (errno
!= ENOENT
) {
1162 if (!sys_path
) sys_path
= "/lib:/usr/local/lib:/usr/lib";
1163 fd
= path_open(name
, sys_path
, buf
, sizeof buf
);
1167 if (fd
< 0) return 0;
1168 if (fstat(fd
, &st
) < 0) {
1172 for (p
=head
->next
; p
; p
=p
->next
) {
1173 if (p
->dev
== st
.st_dev
&& p
->ino
== st
.st_ino
) {
1174 /* If this library was previously loaded with a
1175 * pathname but a search found the same inode,
1176 * setup its shortname so it can be found by name. */
1177 if (!p
->shortname
&& pathname
!= name
)
1178 p
->shortname
= strrchr(p
->name
, '/')+1;
1183 map
= noload
? 0 : map_library(fd
, &temp_dso
);
1187 /* Avoid the danger of getting two versions of libc mapped into the
1188 * same process when an absolute pathname was used. The symbols
1189 * checked are chosen to catch both musl and glibc, and to avoid
1190 * false positives from interposition-hack libraries. */
1191 decode_dyn(&temp_dso
);
1192 if (find_sym(&temp_dso
, "__libc_start_main", 1).sym
&&
1193 find_sym(&temp_dso
, "stdin", 1).sym
) {
1194 unmap_library(&temp_dso
);
1195 return load_library("libc.so", needed_by
);
1197 /* Past this point, if we haven't reached runtime yet, ldso has
1198 * committed either to use the mapped library or to abort execution.
1199 * Unmapping is not possible, so we can safely reclaim gaps. */
1200 if (!runtime
) reclaim_gaps(&temp_dso
);
1202 /* Allocate storage for the new DSO. When there is TLS, this
1203 * storage must include a reservation for all pre-existing
1204 * threads to obtain copies of both the new TLS, and an
1205 * extended DTV capable of storing an additional slot for
1206 * the newly-loaded DSO. */
1207 alloc_size
= sizeof *p
+ strlen(pathname
) + 1;
1208 if (runtime
&& temp_dso
.tls
.image
) {
1209 size_t per_th
= temp_dso
.tls
.size
+ temp_dso
.tls
.align
1210 + sizeof(void *) * (tls_cnt
+3);
1211 n_th
= libc
.threads_minus_1
+ 1;
1212 if (n_th
> SSIZE_MAX
/ per_th
) alloc_size
= SIZE_MAX
;
1213 else alloc_size
+= n_th
* per_th
;
1215 p
= calloc(1, alloc_size
);
1217 unmap_library(&temp_dso
);
1220 memcpy(p
, &temp_dso
, sizeof temp_dso
);
1223 p
->needed_by
= needed_by
;
1225 p
->runtime_loaded
= runtime
;
1226 strcpy(p
->name
, pathname
);
1227 /* Add a shortname only if name arg was not an explicit pathname. */
1228 if (pathname
!= name
) p
->shortname
= strrchr(p
->name
, '/')+1;
1230 p
->tls_id
= ++tls_cnt
;
1231 tls_align
= MAXP2(tls_align
, p
->tls
.align
);
1233 p
->tls
.offset
= tls_offset
+ ( (p
->tls
.align
-1) &
1234 (-tls_offset
+ (uintptr_t)p
->tls
.image
) );
1235 tls_offset
= p
->tls
.offset
+ p
->tls
.size
;
1237 tls_offset
+= p
->tls
.size
+ p
->tls
.align
- 1;
1238 tls_offset
-= (tls_offset
+ (uintptr_t)p
->tls
.image
)
1240 p
->tls
.offset
= tls_offset
;
1242 p
->new_dtv
= (void *)(-sizeof(size_t) &
1243 (uintptr_t)(p
->name
+strlen(p
->name
)+sizeof(size_t)));
1244 p
->new_tls
= (void *)(p
->new_dtv
+ n_th
*(tls_cnt
+1));
1245 if (tls_tail
) tls_tail
->next
= &p
->tls
;
1246 else libc
.tls_head
= &p
->tls
;
1254 if (DL_FDPIC
) makefuncdescs(p
);
1256 if (ldd_mode
) dprintf(1, "\t%s => %s (%p)\n", name
, pathname
, p
->base
);
1261 static void load_direct_deps(struct dso
*p
)
1265 if (p
->deps
) return;
1266 /* For head, all preloads are direct pseudo-dependencies.
1267 * Count and include them now to avoid realloc later. */
1268 if (p
==head
) for (struct dso
*q
=p
->next
; q
; q
=q
->next
)
1270 for (i
=0; p
->dynv
[i
]; i
+=2)
1271 if (p
->dynv
[i
] == DT_NEEDED
) cnt
++;
1272 /* Use builtin buffer for apps with no external deps, to
1273 * preserve property of no runtime failure paths. */
1274 p
->deps
= (p
==head
&& cnt
<2) ? builtin_deps
:
1275 calloc(cnt
+1, sizeof *p
->deps
);
1277 error("Error loading dependencies for %s", p
->name
);
1278 if (runtime
) longjmp(*rtld_fail
, 1);
1281 if (p
==head
) for (struct dso
*q
=p
->next
; q
; q
=q
->next
)
1283 for (i
=0; p
->dynv
[i
]; i
+=2) {
1284 if (p
->dynv
[i
] != DT_NEEDED
) continue;
1285 struct dso
*dep
= load_library(p
->strings
+ p
->dynv
[i
+1], p
);
1287 error("Error loading shared library %s: %m (needed by %s)",
1288 p
->strings
+ p
->dynv
[i
+1], p
->name
);
1289 if (runtime
) longjmp(*rtld_fail
, 1);
1292 p
->deps
[cnt
++] = dep
;
1295 p
->ndeps_direct
= cnt
;
1298 static void load_deps(struct dso
*p
)
1300 if (p
->deps
) return;
1301 for (; p
; p
=p
->next
)
1302 load_direct_deps(p
);
1305 static void extend_bfs_deps(struct dso
*p
)
1307 size_t i
, j
, cnt
, ndeps_all
;
1310 /* Can't use realloc if the original p->deps was allocated at
1311 * program entry and malloc has been replaced, or if it's
1312 * the builtin non-allocated trivial main program deps array. */
1313 int no_realloc
= (__malloc_replaced
&& !p
->runtime_loaded
)
1314 || p
->deps
== builtin_deps
;
1316 if (p
->bfs_built
) return;
1317 ndeps_all
= p
->ndeps_direct
;
1319 /* Mark existing (direct) deps so they won't be duplicated. */
1320 for (i
=0; p
->deps
[i
]; i
++)
1321 p
->deps
[i
]->mark
= 1;
1323 /* For each dependency already in the list, copy its list of direct
1324 * dependencies to the list, excluding any items already in the
1325 * list. Note that the list this loop iterates over will grow during
1326 * the loop, but since duplicates are excluded, growth is bounded. */
1327 for (i
=0; p
->deps
[i
]; i
++) {
1328 struct dso
*dep
= p
->deps
[i
];
1329 for (j
=cnt
=0; j
<dep
->ndeps_direct
; j
++)
1330 if (!dep
->deps
[j
]->mark
) cnt
++;
1332 malloc(sizeof(*tmp
) * (ndeps_all
+cnt
+1)) :
1333 realloc(p
->deps
, sizeof(*tmp
) * (ndeps_all
+cnt
+1));
1335 error("Error recording dependencies for %s", p
->name
);
1336 if (runtime
) longjmp(*rtld_fail
, 1);
1340 memcpy(tmp
, p
->deps
, sizeof(*tmp
) * (ndeps_all
+1));
1344 for (j
=0; j
<dep
->ndeps_direct
; j
++) {
1345 if (dep
->deps
[j
]->mark
) continue;
1346 dep
->deps
[j
]->mark
= 1;
1347 p
->deps
[ndeps_all
++] = dep
->deps
[j
];
1349 p
->deps
[ndeps_all
] = 0;
1352 for (p
=head
; p
; p
=p
->next
)
1356 static void load_preload(char *s
)
1360 for (z
=s
; *z
; s
=z
) {
1361 for ( ; *s
&& (isspace(*s
) || *s
==':'); s
++);
1362 for (z
=s
; *z
&& !isspace(*z
) && *z
!=':'; z
++);
1370 static void add_syms(struct dso
*p
)
1372 if (!p
->syms_next
&& syms_tail
!= p
) {
1373 syms_tail
->syms_next
= p
;
1378 static void revert_syms(struct dso
*old_tail
)
1380 struct dso
*p
, *next
;
1381 /* Chop off the tail of the list of dsos that participate in
1382 * the global symbol table, reverting them to RTLD_LOCAL. */
1383 for (p
=old_tail
; p
; p
=next
) {
1384 next
= p
->syms_next
;
1387 syms_tail
= old_tail
;
1390 static void do_mips_relocs(struct dso
*p
, size_t *got
)
1392 size_t i
, j
, rel
[2];
1393 unsigned char *base
= p
->base
;
1394 i
=0; search_vec(p
->dynv
, &i
, DT_MIPS_LOCAL_GOTNO
);
1398 while (i
--) *got
++ += (size_t)base
;
1400 j
=0; search_vec(p
->dynv
, &j
, DT_MIPS_GOTSYM
);
1401 i
=0; search_vec(p
->dynv
, &i
, DT_MIPS_SYMTABNO
);
1402 Sym
*sym
= p
->syms
+ j
;
1403 rel
[0] = (unsigned char *)got
- base
;
1404 for (i
-=j
; i
; i
--, sym
++, rel
[0]+=sizeof(size_t)) {
1405 rel
[1] = R_INFO(sym
-p
->syms
, R_MIPS_JUMP_SLOT
);
1406 do_relocs(p
, rel
, sizeof rel
, 2);
1410 static void reloc_all(struct dso
*p
)
1412 size_t dyn
[DYN_CNT
];
1413 for (; p
; p
=p
->next
) {
1414 if (p
->relocated
) continue;
1415 decode_vec(p
->dynv
, dyn
, DYN_CNT
);
1416 if (NEED_MIPS_GOT_RELOCS
)
1417 do_mips_relocs(p
, laddr(p
, dyn
[DT_PLTGOT
]));
1418 do_relocs(p
, laddr(p
, dyn
[DT_JMPREL
]), dyn
[DT_PLTRELSZ
],
1419 2+(dyn
[DT_PLTREL
]==DT_RELA
));
1420 do_relocs(p
, laddr(p
, dyn
[DT_REL
]), dyn
[DT_RELSZ
], 2);
1421 do_relocs(p
, laddr(p
, dyn
[DT_RELA
]), dyn
[DT_RELASZ
], 3);
1423 do_relr_relocs(p
, laddr(p
, dyn
[DT_RELR
]), dyn
[DT_RELRSZ
]);
1425 if (head
!= &ldso
&& p
->relro_start
!= p
->relro_end
) {
1426 long ret
= __syscall(SYS_mprotect
, laddr(p
, p
->relro_start
),
1427 p
->relro_end
-p
->relro_start
, PROT_READ
);
1428 if (ret
!= 0 && ret
!= -ENOSYS
) {
1429 error("Error relocating %s: RELRO protection failed: %m",
1431 if (runtime
) longjmp(*rtld_fail
, 1);
1439 static void kernel_mapped_dso(struct dso
*p
)
1441 size_t min_addr
= -1, max_addr
= 0, cnt
;
1443 for (cnt
= p
->phnum
; cnt
--; ph
= (void *)((char *)ph
+ p
->phentsize
)) {
1444 if (ph
->p_type
== PT_DYNAMIC
) {
1445 p
->dynv
= laddr(p
, ph
->p_vaddr
);
1446 } else if (ph
->p_type
== PT_GNU_RELRO
) {
1447 p
->relro_start
= ph
->p_vaddr
& -PAGE_SIZE
;
1448 p
->relro_end
= (ph
->p_vaddr
+ ph
->p_memsz
) & -PAGE_SIZE
;
1449 } else if (ph
->p_type
== PT_GNU_STACK
) {
1450 if (!runtime
&& ph
->p_memsz
> __default_stacksize
) {
1451 __default_stacksize
=
1452 ph
->p_memsz
< DEFAULT_STACK_MAX
?
1453 ph
->p_memsz
: DEFAULT_STACK_MAX
;
1456 if (ph
->p_type
!= PT_LOAD
) continue;
1457 if (ph
->p_vaddr
< min_addr
)
1458 min_addr
= ph
->p_vaddr
;
1459 if (ph
->p_vaddr
+ph
->p_memsz
> max_addr
)
1460 max_addr
= ph
->p_vaddr
+ph
->p_memsz
;
1462 min_addr
&= -PAGE_SIZE
;
1463 max_addr
= (max_addr
+ PAGE_SIZE
-1) & -PAGE_SIZE
;
1464 p
->map
= p
->base
+ min_addr
;
1465 p
->map_len
= max_addr
- min_addr
;
1466 p
->kernel_mapped
= 1;
1469 void __libc_exit_fini()
1472 size_t dyn
[DYN_CNT
];
1473 pthread_t self
= __pthread_self();
1475 /* Take both locks before setting shutting_down, so that
1476 * either lock is sufficient to read its value. The lock
1477 * order matches that in dlopen to avoid deadlock. */
1478 pthread_rwlock_wrlock(&lock
);
1479 pthread_mutex_lock(&init_fini_lock
);
1481 pthread_rwlock_unlock(&lock
);
1482 for (p
=fini_head
; p
; p
=p
->fini_next
) {
1483 while (p
->ctor_visitor
&& p
->ctor_visitor
!=self
)
1484 pthread_cond_wait(&ctor_cond
, &init_fini_lock
);
1485 if (!p
->constructed
) continue;
1486 decode_vec(p
->dynv
, dyn
, DYN_CNT
);
1487 if (dyn
[0] & (1<<DT_FINI_ARRAY
)) {
1488 size_t n
= dyn
[DT_FINI_ARRAYSZ
]/sizeof(size_t);
1489 size_t *fn
= (size_t *)laddr(p
, dyn
[DT_FINI_ARRAY
])+n
;
1490 while (n
--) ((void (*)(void))*--fn
)();
1492 #ifndef NO_LEGACY_INITFINI
1493 if ((dyn
[0] & (1<<DT_FINI
)) && dyn
[DT_FINI
])
1494 fpaddr(p
, dyn
[DT_FINI
])();
1499 void __ldso_atfork(int who
)
1502 pthread_rwlock_wrlock(&lock
);
1503 pthread_mutex_lock(&init_fini_lock
);
1505 pthread_mutex_unlock(&init_fini_lock
);
1506 pthread_rwlock_unlock(&lock
);
1510 static struct dso
**queue_ctors(struct dso
*dso
)
1512 size_t cnt
, qpos
, spos
, i
;
1513 struct dso
*p
, **queue
, **stack
;
1515 if (ldd_mode
) return 0;
1517 /* Bound on queue size is the total number of indirect deps.
1518 * If a bfs deps list was built, we can use it. Otherwise,
1519 * bound by the total number of DSOs, which is always safe and
1520 * is reasonable we use it (for main app at startup). */
1521 if (dso
->bfs_built
) {
1522 for (cnt
=0; dso
->deps
[cnt
]; cnt
++)
1523 dso
->deps
[cnt
]->mark
= 0;
1524 cnt
++; /* self, not included in deps */
1526 for (cnt
=0, p
=head
; p
; cnt
++, p
=p
->next
)
1529 cnt
++; /* termination slot */
1530 if (dso
==head
&& cnt
<= countof(builtin_ctor_queue
))
1531 queue
= builtin_ctor_queue
;
1533 queue
= calloc(cnt
, sizeof *queue
);
1536 error("Error allocating constructor queue: %m\n");
1537 if (runtime
) longjmp(*rtld_fail
, 1);
1541 /* Opposite ends of the allocated buffer serve as an output queue
1542 * and a working stack. Setup initial stack with just the argument
1543 * dso and initial queue empty... */
1547 stack
[--spos
] = dso
;
1551 /* Then perform pseudo-DFS sort, but ignoring circular deps. */
1554 while (p
->next_dep
< p
->ndeps_direct
) {
1555 if (p
->deps
[p
->next_dep
]->mark
) {
1559 p
= p
->deps
[p
->next_dep
];
1567 for (i
=0; i
<qpos
; i
++) queue
[i
]->mark
= 0;
1568 for (i
=0; i
<qpos
; i
++)
1569 if (queue
[i
]->ctor_visitor
&& queue
[i
]->ctor_visitor
->tid
< 0) {
1570 error("State of %s is inconsistent due to multithreaded fork\n",
1573 if (runtime
) longjmp(*rtld_fail
, 1);
1579 static void do_init_fini(struct dso
**queue
)
1582 size_t dyn
[DYN_CNT
], i
;
1583 pthread_t self
= __pthread_self();
1585 pthread_mutex_lock(&init_fini_lock
);
1586 for (i
=0; (p
=queue
[i
]); i
++) {
1587 while ((p
->ctor_visitor
&& p
->ctor_visitor
!=self
) || shutting_down
)
1588 pthread_cond_wait(&ctor_cond
, &init_fini_lock
);
1589 if (p
->ctor_visitor
|| p
->constructed
)
1591 p
->ctor_visitor
= self
;
1593 decode_vec(p
->dynv
, dyn
, DYN_CNT
);
1594 if (dyn
[0] & ((1<<DT_FINI
) | (1<<DT_FINI_ARRAY
))) {
1595 p
->fini_next
= fini_head
;
1599 pthread_mutex_unlock(&init_fini_lock
);
1601 #ifndef NO_LEGACY_INITFINI
1602 if ((dyn
[0] & (1<<DT_INIT
)) && dyn
[DT_INIT
])
1603 fpaddr(p
, dyn
[DT_INIT
])();
1605 if (dyn
[0] & (1<<DT_INIT_ARRAY
)) {
1606 size_t n
= dyn
[DT_INIT_ARRAYSZ
]/sizeof(size_t);
1607 size_t *fn
= laddr(p
, dyn
[DT_INIT_ARRAY
]);
1608 while (n
--) ((void (*)(void))*fn
++)();
1611 pthread_mutex_lock(&init_fini_lock
);
1612 p
->ctor_visitor
= 0;
1614 pthread_cond_broadcast(&ctor_cond
);
1616 pthread_mutex_unlock(&init_fini_lock
);
1619 void __libc_start_init(void)
1621 do_init_fini(main_ctor_queue
);
1622 if (!__malloc_replaced
&& main_ctor_queue
!= builtin_ctor_queue
)
1623 free(main_ctor_queue
);
1624 main_ctor_queue
= 0;
1627 static void dl_debug_state(void)
1631 weak_alias(dl_debug_state
, _dl_debug_state
);
1633 void __init_tls(size_t *auxv
)
1637 static void update_tls_size()
1639 libc
.tls_cnt
= tls_cnt
;
1640 libc
.tls_align
= tls_align
;
1641 libc
.tls_size
= ALIGN(
1642 (1+tls_cnt
) * sizeof(void *) +
1644 sizeof(struct pthread
) +
1649 static void install_new_tls(void)
1652 pthread_t self
= __pthread_self(), td
;
1653 struct dso
*dtv_provider
= container_of(tls_tail
, struct dso
, tls
);
1654 uintptr_t (*newdtv
)[tls_cnt
+1] = (void *)dtv_provider
->new_dtv
;
1657 size_t old_cnt
= self
->dtv
[0];
1659 __block_app_sigs(&set
);
1661 /* Copy existing dtv contents from all existing threads. */
1662 for (i
=0, td
=self
; !i
|| td
!=self
; i
++, td
=td
->next
) {
1663 memcpy(newdtv
+i
, td
->dtv
,
1664 (old_cnt
+1)*sizeof(uintptr_t));
1665 newdtv
[i
][0] = tls_cnt
;
1667 /* Install new dtls into the enlarged, uninstalled dtv copies. */
1668 for (p
=head
; ; p
=p
->next
) {
1669 if (p
->tls_id
<= old_cnt
) continue;
1670 unsigned char *mem
= p
->new_tls
;
1671 for (j
=0; j
<i
; j
++) {
1672 unsigned char *new = mem
;
1673 new += ((uintptr_t)p
->tls
.image
- (uintptr_t)mem
)
1675 memcpy(new, p
->tls
.image
, p
->tls
.len
);
1676 newdtv
[j
][p
->tls_id
] =
1677 (uintptr_t)new + DTP_OFFSET
;
1678 mem
+= p
->tls
.size
+ p
->tls
.align
;
1680 if (p
->tls_id
== tls_cnt
) break;
1683 /* Broadcast barrier to ensure contents of new dtv is visible
1684 * if the new dtv pointer is. The __membarrier function has a
1685 * fallback emulation using signals for kernels that lack the
1686 * feature at the syscall level. */
1688 __membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED
, 0);
1690 /* Install new dtv for each thread. */
1691 for (j
=0, td
=self
; !j
|| td
!=self
; j
++, td
=td
->next
) {
1692 td
->dtv
= newdtv
[j
];
1696 __restore_sigs(&set
);
1699 /* Stage 1 of the dynamic linker is defined in dlstart.c. It calls the
1700 * following stage 2 and stage 3 functions via primitive symbolic lookup
1701 * since it does not have access to their addresses to begin with. */
1703 /* Stage 2 of the dynamic linker is called after relative relocations
1704 * have been processed. It can make function calls to static functions
1705 * and access string literals and static data, but cannot use extern
1706 * symbols. Its job is to perform symbolic relocations on the dynamic
1707 * linker itself, but some of the relocations performed may need to be
1708 * replaced later due to copy relocations in the main program. */
1710 hidden
void __dls2(unsigned char *base
, size_t *sp
)
1713 for (auxv
=sp
+1+*sp
+1; *auxv
; auxv
++);
1716 void *p1
= (void *)sp
[-2];
1717 void *p2
= (void *)sp
[-1];
1719 size_t aux
[AUX_CNT
];
1720 decode_vec(auxv
, aux
, AUX_CNT
);
1721 if (aux
[AT_BASE
]) ldso
.base
= (void *)aux
[AT_BASE
];
1722 else ldso
.base
= (void *)(aux
[AT_PHDR
] & -4096);
1724 app_loadmap
= p2
? p1
: 0;
1725 ldso
.loadmap
= p2
? p2
: p1
;
1726 ldso
.base
= laddr(&ldso
, 0);
1730 Ehdr
*ehdr
= __ehdr_start
? (void *)__ehdr_start
: (void *)ldso
.base
;
1731 ldso
.name
= ldso
.shortname
= "libc.so";
1732 ldso
.phnum
= ehdr
->e_phnum
;
1733 ldso
.phdr
= laddr(&ldso
, ehdr
->e_phoff
);
1734 ldso
.phentsize
= ehdr
->e_phentsize
;
1735 search_vec(auxv
, &ldso_page_size
, AT_PAGESZ
);
1736 kernel_mapped_dso(&ldso
);
1739 if (DL_FDPIC
) makefuncdescs(&ldso
);
1741 /* Prepare storage for to save clobbered REL addends so they
1742 * can be reused in stage 3. There should be very few. If
1743 * something goes wrong and there are a huge number, abort
1744 * instead of risking stack overflow. */
1745 size_t dyn
[DYN_CNT
];
1746 decode_vec(ldso
.dynv
, dyn
, DYN_CNT
);
1747 size_t *rel
= laddr(&ldso
, dyn
[DT_REL
]);
1748 size_t rel_size
= dyn
[DT_RELSZ
];
1749 size_t symbolic_rel_cnt
= 0;
1750 apply_addends_to
= rel
;
1751 for (; rel_size
; rel
+=2, rel_size
-=2*sizeof(size_t))
1752 if (!IS_RELATIVE(rel
[1], ldso
.syms
)) symbolic_rel_cnt
++;
1753 if (symbolic_rel_cnt
>= ADDEND_LIMIT
) a_crash();
1754 size_t addends
[symbolic_rel_cnt
+1];
1755 saved_addends
= addends
;
1762 /* Call dynamic linker stage-2b, __dls2b, looking it up
1763 * symbolically as a barrier against moving the address
1764 * load across the above relocation processing. */
1765 struct symdef dls2b_def
= find_sym(&ldso
, "__dls2b", 0);
1766 if (DL_FDPIC
) ((stage3_func
)&ldso
.funcdescs
[dls2b_def
.sym
-ldso
.syms
])(sp
, auxv
);
1767 else ((stage3_func
)laddr(&ldso
, dls2b_def
.sym
->st_value
))(sp
, auxv
);
1770 /* Stage 2b sets up a valid thread pointer, which requires relocations
1771 * completed in stage 2, and on which stage 3 is permitted to depend.
1772 * This is done as a separate stage, with symbolic lookup as a barrier,
1773 * so that loads of the thread pointer and &errno can be pure/const and
1774 * thereby hoistable. */
1776 void __dls2b(size_t *sp
, size_t *auxv
)
1778 /* Setup early thread pointer in builtin_tls for ldso/libc itself to
1779 * use during dynamic linking. If possible it will also serve as the
1780 * thread pointer at runtime. */
1781 search_vec(auxv
, &__hwcap
, AT_HWCAP
);
1783 libc
.tls_size
= sizeof builtin_tls
;
1784 libc
.tls_align
= tls_align
;
1785 if (__init_tp(__copy_tls((void *)builtin_tls
)) < 0) {
1789 struct symdef dls3_def
= find_sym(&ldso
, "__dls3", 0);
1790 if (DL_FDPIC
) ((stage3_func
)&ldso
.funcdescs
[dls3_def
.sym
-ldso
.syms
])(sp
, auxv
);
1791 else ((stage3_func
)laddr(&ldso
, dls3_def
.sym
->st_value
))(sp
, auxv
);
1794 /* Stage 3 of the dynamic linker is called with the dynamic linker/libc
1795 * fully functional. Its job is to load (if not already loaded) and
1796 * process dependencies and relocations for the main application and
1797 * transfer control to its entry point. */
1799 void __dls3(size_t *sp
, size_t *auxv
)
1801 static struct dso app
, vdso
;
1802 size_t aux
[AUX_CNT
];
1804 char *env_preload
=0;
1805 char *replace_argv0
=0;
1808 char **argv
= (void *)(sp
+1);
1809 char **argv_orig
= argv
;
1810 char **envp
= argv
+argc
+1;
1812 /* Find aux vector just past environ[] and use it to initialize
1813 * global data that may be needed before we can make syscalls. */
1815 decode_vec(auxv
, aux
, AUX_CNT
);
1816 search_vec(auxv
, &__sysinfo
, AT_SYSINFO
);
1817 __pthread_self()->sysinfo
= __sysinfo
;
1818 libc
.page_size
= aux
[AT_PAGESZ
];
1819 libc
.secure
= ((aux
[0]&0x7800)!=0x7800 || aux
[AT_UID
]!=aux
[AT_EUID
]
1820 || aux
[AT_GID
]!=aux
[AT_EGID
] || aux
[AT_SECURE
]);
1822 /* Only trust user/env if kernel says we're not suid/sgid */
1824 env_path
= getenv("LD_LIBRARY_PATH");
1825 env_preload
= getenv("LD_PRELOAD");
1828 /* Activate error handler function */
1831 /* If the main program was already loaded by the kernel,
1832 * AT_PHDR will point to some location other than the dynamic
1833 * linker's program headers. */
1834 if (aux
[AT_PHDR
] != (size_t)ldso
.phdr
) {
1835 size_t interp_off
= 0;
1836 size_t tls_image
= 0;
1837 /* Find load address of the main program, via AT_PHDR vs PT_PHDR. */
1838 Phdr
*phdr
= app
.phdr
= (void *)aux
[AT_PHDR
];
1839 app
.phnum
= aux
[AT_PHNUM
];
1840 app
.phentsize
= aux
[AT_PHENT
];
1841 for (i
=aux
[AT_PHNUM
]; i
; i
--, phdr
=(void *)((char *)phdr
+ aux
[AT_PHENT
])) {
1842 if (phdr
->p_type
== PT_PHDR
)
1843 app
.base
= (void *)(aux
[AT_PHDR
] - phdr
->p_vaddr
);
1844 else if (phdr
->p_type
== PT_INTERP
)
1845 interp_off
= (size_t)phdr
->p_vaddr
;
1846 else if (phdr
->p_type
== PT_TLS
) {
1847 tls_image
= phdr
->p_vaddr
;
1848 app
.tls
.len
= phdr
->p_filesz
;
1849 app
.tls
.size
= phdr
->p_memsz
;
1850 app
.tls
.align
= phdr
->p_align
;
1853 if (DL_FDPIC
) app
.loadmap
= app_loadmap
;
1854 if (app
.tls
.size
) app
.tls
.image
= laddr(&app
, tls_image
);
1855 if (interp_off
) ldso
.name
= laddr(&app
, interp_off
);
1856 if ((aux
[0] & (1UL<<AT_EXECFN
))
1857 && strncmp((char *)aux
[AT_EXECFN
], "/proc/", 6))
1858 app
.name
= (char *)aux
[AT_EXECFN
];
1861 kernel_mapped_dso(&app
);
1864 char *ldname
= argv
[0];
1865 size_t l
= strlen(ldname
);
1866 if (l
>= 3 && !strcmp(ldname
+l
-3, "ldd")) ldd_mode
= 1;
1868 while (argv
[0] && argv
[0][0]=='-' && argv
[0][1]=='-') {
1869 char *opt
= argv
[0]+2;
1870 *argv
++ = (void *)-1;
1873 } else if (!memcmp(opt
, "list", 5)) {
1875 } else if (!memcmp(opt
, "library-path", 12)) {
1876 if (opt
[12]=='=') env_path
= opt
+13;
1877 else if (opt
[12]) *argv
= 0;
1878 else if (*argv
) env_path
= *argv
++;
1879 } else if (!memcmp(opt
, "preload", 7)) {
1880 if (opt
[7]=='=') env_preload
= opt
+8;
1881 else if (opt
[7]) *argv
= 0;
1882 else if (*argv
) env_preload
= *argv
++;
1883 } else if (!memcmp(opt
, "argv0", 5)) {
1884 if (opt
[5]=='=') replace_argv0
= opt
+6;
1885 else if (opt
[5]) *argv
= 0;
1886 else if (*argv
) replace_argv0
= *argv
++;
1891 argv
[-1] = (void *)(argc
- (argv
-argv_orig
));
1893 dprintf(2, "musl libc (" LDSO_ARCH
")\n"
1895 "Dynamic Program Loader\n"
1896 "Usage: %s [options] [--] pathname%s\n",
1897 __libc_version
, ldname
,
1898 ldd_mode
? "" : " [args]");
1901 fd
= open(argv
[0], O_RDONLY
);
1903 dprintf(2, "%s: cannot load %s: %s\n", ldname
, argv
[0], strerror(errno
));
1906 Ehdr
*ehdr
= map_library(fd
, &app
);
1908 dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname
, argv
[0]);
1914 aux
[AT_ENTRY
] = (size_t)laddr(&app
, ehdr
->e_entry
);
1915 /* Find the name that would have been used for the dynamic
1916 * linker had ldd not taken its place. */
1918 for (i
=0; i
<app
.phnum
; i
++) {
1919 if (app
.phdr
[i
].p_type
== PT_INTERP
)
1920 ldso
.name
= laddr(&app
, app
.phdr
[i
].p_vaddr
);
1922 dprintf(1, "\t%s (%p)\n", ldso
.name
, ldso
.base
);
1926 libc
.tls_head
= tls_tail
= &app
.tls
;
1927 app
.tls_id
= tls_cnt
= 1;
1929 app
.tls
.offset
= GAP_ABOVE_TP
;
1930 app
.tls
.offset
+= (-GAP_ABOVE_TP
+ (uintptr_t)app
.tls
.image
)
1931 & (app
.tls
.align
-1);
1932 tls_offset
= app
.tls
.offset
+ app
.tls
.size
;
1934 tls_offset
= app
.tls
.offset
= app
.tls
.size
1935 + ( -((uintptr_t)app
.tls
.image
+ app
.tls
.size
)
1936 & (app
.tls
.align
-1) );
1938 tls_align
= MAXP2(tls_align
, app
.tls
.align
);
1942 makefuncdescs(&app
);
1944 app
.loadmap
= (void *)&app_dummy_loadmap
;
1945 app
.loadmap
->nsegs
= 1;
1946 app
.loadmap
->segs
[0].addr
= (size_t)app
.map
;
1947 app
.loadmap
->segs
[0].p_vaddr
= (size_t)app
.map
1949 app
.loadmap
->segs
[0].p_memsz
= app
.map_len
;
1951 argv
[-3] = (void *)app
.loadmap
;
1954 /* Initial dso chain consists only of the app. */
1955 head
= tail
= syms_tail
= &app
;
1957 /* Donate unused parts of app and library mapping to malloc */
1959 reclaim_gaps(&ldso
);
1961 /* Load preload/needed libraries, add symbols to global namespace. */
1962 ldso
.deps
= (struct dso
**)no_deps
;
1963 if (env_preload
) load_preload(env_preload
);
1965 for (struct dso
*p
=head
; p
; p
=p
->next
)
1968 /* Attach to vdso, if provided by the kernel, last so that it does
1969 * not become part of the global namespace. */
1970 if (search_vec(auxv
, &vdso_base
, AT_SYSINFO_EHDR
) && vdso_base
) {
1971 Ehdr
*ehdr
= (void *)vdso_base
;
1972 Phdr
*phdr
= vdso
.phdr
= (void *)(vdso_base
+ ehdr
->e_phoff
);
1973 vdso
.phnum
= ehdr
->e_phnum
;
1974 vdso
.phentsize
= ehdr
->e_phentsize
;
1975 for (i
=ehdr
->e_phnum
; i
; i
--, phdr
=(void *)((char *)phdr
+ ehdr
->e_phentsize
)) {
1976 if (phdr
->p_type
== PT_DYNAMIC
)
1977 vdso
.dynv
= (void *)(vdso_base
+ phdr
->p_offset
);
1978 if (phdr
->p_type
== PT_LOAD
)
1979 vdso
.base
= (void *)(vdso_base
- phdr
->p_vaddr
+ phdr
->p_offset
);
1982 vdso
.shortname
= "linux-gate.so.1";
1984 vdso
.deps
= (struct dso
**)no_deps
;
1991 for (i
=0; app
.dynv
[i
]; i
+=2) {
1992 if (!DT_DEBUG_INDIRECT
&& app
.dynv
[i
]==DT_DEBUG
)
1993 app
.dynv
[i
+1] = (size_t)&debug
;
1994 if (DT_DEBUG_INDIRECT
&& app
.dynv
[i
]==DT_DEBUG_INDIRECT
) {
1995 size_t *ptr
= (size_t *) app
.dynv
[i
+1];
1996 *ptr
= (size_t)&debug
;
1998 if (app
.dynv
[i
]==DT_DEBUG_INDIRECT_REL
) {
1999 size_t *ptr
= (size_t *)((size_t)&app
.dynv
[i
] + app
.dynv
[i
+1]);
2000 *ptr
= (size_t)&debug
;
2004 /* This must be done before final relocations, since it calls
2005 * malloc, which may be provided by the application. Calling any
2006 * application code prior to the jump to its entry point is not
2007 * valid in our model and does not work with FDPIC, where there
2008 * are additional relocation-like fixups that only the entry point
2009 * code can see to perform. */
2010 main_ctor_queue
= queue_ctors(&app
);
2012 /* Initial TLS must also be allocated before final relocations
2013 * might result in calloc being a call to application code. */
2015 void *initial_tls
= builtin_tls
;
2016 if (libc
.tls_size
> sizeof builtin_tls
|| tls_align
> MIN_TLS_ALIGN
) {
2017 initial_tls
= calloc(libc
.tls_size
, 1);
2019 dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
2020 argv
[0], libc
.tls_size
);
2024 static_tls_cnt
= tls_cnt
;
2026 /* The main program must be relocated LAST since it may contain
2027 * copy relocations which depend on libraries' relocations. */
2028 reloc_all(app
.next
);
2031 /* Actual copying to new TLS needs to happen after relocations,
2032 * since the TLS images might have contained relocated addresses. */
2033 if (initial_tls
!= builtin_tls
) {
2034 if (__init_tp(__copy_tls(initial_tls
)) < 0) {
2038 size_t tmp_tls_size
= libc
.tls_size
;
2039 pthread_t self
= __pthread_self();
2040 /* Temporarily set the tls size to the full size of
2041 * builtin_tls so that __copy_tls will use the same layout
2042 * as it did for before. Then check, just to be safe. */
2043 libc
.tls_size
= sizeof builtin_tls
;
2044 if (__copy_tls((void*)builtin_tls
) != self
) a_crash();
2045 libc
.tls_size
= tmp_tls_size
;
2048 if (ldso_fail
) _exit(127);
2049 if (ldd_mode
) _exit(0);
2051 /* Determine if malloc was interposed by a replacement implementation
2052 * so that calloc and the memalign family can harden against the
2053 * possibility of incomplete replacement. */
2054 if (find_sym(head
, "malloc", 1).dso
!= &ldso
)
2055 __malloc_replaced
= 1;
2056 if (find_sym(head
, "aligned_alloc", 1).dso
!= &ldso
)
2057 __aligned_alloc_replaced
= 1;
2059 /* Switch to runtime mode: any further failures in the dynamic
2060 * linker are a reportable failure rather than a fatal startup
2065 debug
.bp
= dl_debug_state
;
2067 debug
.base
= ldso
.base
;
2068 debug
.state
= RT_CONSISTENT
;
2071 if (replace_argv0
) argv
[0] = replace_argv0
;
2075 CRTJMP((void *)aux
[AT_ENTRY
], argv
-1);
2079 static void prepare_lazy(struct dso
*p
)
2081 size_t dyn
[DYN_CNT
], n
, flags1
=0;
2082 decode_vec(p
->dynv
, dyn
, DYN_CNT
);
2083 search_vec(p
->dynv
, &flags1
, DT_FLAGS_1
);
2084 if (dyn
[DT_BIND_NOW
] || (dyn
[DT_FLAGS
] & DF_BIND_NOW
) || (flags1
& DF_1_NOW
))
2086 n
= dyn
[DT_RELSZ
]/2 + dyn
[DT_RELASZ
]/3 + dyn
[DT_PLTRELSZ
]/2 + 1;
2087 if (NEED_MIPS_GOT_RELOCS
) {
2088 size_t j
=0; search_vec(p
->dynv
, &j
, DT_MIPS_GOTSYM
);
2089 size_t i
=0; search_vec(p
->dynv
, &i
, DT_MIPS_SYMTABNO
);
2092 p
->lazy
= calloc(n
, 3*sizeof(size_t));
2094 error("Error preparing lazy relocation for %s: %m", p
->name
);
2095 longjmp(*rtld_fail
, 1);
2097 p
->lazy_next
= lazy_head
;
2101 void *dlopen(const char *file
, int mode
)
2103 struct dso
*volatile p
, *orig_tail
, *orig_syms_tail
, *orig_lazy_head
, *next
;
2104 struct tls_module
*orig_tls_tail
;
2105 size_t orig_tls_cnt
, orig_tls_offset
, orig_tls_align
;
2109 struct dso
**volatile ctor_queue
= 0;
2111 if (!file
) return head
;
2113 pthread_setcancelstate(PTHREAD_CANCEL_DISABLE
, &cs
);
2114 pthread_rwlock_wrlock(&lock
);
2117 debug
.state
= RT_ADD
;
2121 if (shutting_down
) {
2122 error("Cannot dlopen while program is exiting.");
2125 orig_tls_tail
= tls_tail
;
2126 orig_tls_cnt
= tls_cnt
;
2127 orig_tls_offset
= tls_offset
;
2128 orig_tls_align
= tls_align
;
2129 orig_lazy_head
= lazy_head
;
2130 orig_syms_tail
= syms_tail
;
2132 noload
= mode
& RTLD_NOLOAD
;
2135 if (setjmp(*rtld_fail
)) {
2136 /* Clean up anything new that was (partially) loaded */
2137 revert_syms(orig_syms_tail
);
2138 for (p
=orig_tail
->next
; p
; p
=next
) {
2140 while (p
->td_index
) {
2141 void *tmp
= p
->td_index
->next
;
2146 if (p
->rpath
!= p
->rpath_orig
)
2154 if (!orig_tls_tail
) libc
.tls_head
= 0;
2155 tls_tail
= orig_tls_tail
;
2156 if (tls_tail
) tls_tail
->next
= 0;
2157 tls_cnt
= orig_tls_cnt
;
2158 tls_offset
= orig_tls_offset
;
2159 tls_align
= orig_tls_align
;
2160 lazy_head
= orig_lazy_head
;
2165 } else p
= load_library(file
, head
);
2169 "Library %s is not already loaded" :
2170 "Error loading shared library %s: %m",
2175 /* First load handling */
2178 pthread_mutex_lock(&init_fini_lock
);
2179 int constructed
= p
->constructed
;
2180 pthread_mutex_unlock(&init_fini_lock
);
2181 if (!constructed
) ctor_queue
= queue_ctors(p
);
2182 if (!p
->relocated
&& (mode
& RTLD_LAZY
)) {
2184 for (i
=0; p
->deps
[i
]; i
++)
2185 if (!p
->deps
[i
]->relocated
)
2186 prepare_lazy(p
->deps
[i
]);
2188 if (!p
->relocated
|| (mode
& RTLD_GLOBAL
)) {
2189 /* Make new symbols global, at least temporarily, so we can do
2190 * relocations. If not RTLD_GLOBAL, this is reverted below. */
2192 for (i
=0; p
->deps
[i
]; i
++)
2193 add_syms(p
->deps
[i
]);
2195 if (!p
->relocated
) {
2199 /* If RTLD_GLOBAL was not specified, undo any new additions
2200 * to the global symbol table. This is a nop if the library was
2201 * previously loaded and already global. */
2202 if (!(mode
& RTLD_GLOBAL
))
2203 revert_syms(orig_syms_tail
);
2205 /* Processing of deferred lazy relocations must not happen until
2206 * the new libraries are committed; otherwise we could end up with
2207 * relocations resolved to symbol definitions that get removed. */
2211 if (tls_cnt
!= orig_tls_cnt
)
2215 debug
.state
= RT_CONSISTENT
;
2219 pthread_rwlock_unlock(&lock
);
2221 do_init_fini(ctor_queue
);
2224 pthread_setcancelstate(cs
, 0);
2228 hidden
int __dl_invalid_handle(void *h
)
2231 for (p
=head
; p
; p
=p
->next
) if (h
==p
) return 0;
2232 error("Invalid library handle %p", (void *)h
);
2236 static void *addr2dso(size_t a
)
2240 if (DL_FDPIC
) for (p
=head
; p
; p
=p
->next
) {
2242 if (a
-(size_t)p
->funcdescs
< i
*sizeof(*p
->funcdescs
))
2245 for (p
=head
; p
; p
=p
->next
) {
2246 if (DL_FDPIC
&& p
->loadmap
) {
2247 for (i
=0; i
<p
->loadmap
->nsegs
; i
++) {
2248 if (a
-p
->loadmap
->segs
[i
].p_vaddr
2249 < p
->loadmap
->segs
[i
].p_memsz
)
2254 size_t phcnt
= p
->phnum
;
2255 size_t entsz
= p
->phentsize
;
2256 size_t base
= (size_t)p
->base
;
2257 for (; phcnt
--; ph
=(void *)((char *)ph
+entsz
)) {
2258 if (ph
->p_type
!= PT_LOAD
) continue;
2259 if (a
-base
-ph
->p_vaddr
< ph
->p_memsz
)
2262 if (a
-(size_t)p
->map
< p
->map_len
)
2269 static void *do_dlsym(struct dso
*p
, const char *s
, void *ra
)
2272 if (p
== head
|| p
== RTLD_DEFAULT
) {
2274 } else if (p
== RTLD_NEXT
) {
2275 p
= addr2dso((size_t)ra
);
2278 } else if (__dl_invalid_handle(p
)) {
2282 struct symdef def
= find_sym2(p
, s
, 0, use_deps
);
2284 error("Symbol not found: %s", s
);
2287 if ((def
.sym
->st_info
&0xf) == STT_TLS
)
2288 return __tls_get_addr((tls_mod_off_t
[]){def
.dso
->tls_id
, def
.sym
->st_value
-DTP_OFFSET
});
2289 if (DL_FDPIC
&& (def
.sym
->st_info
&0xf) == STT_FUNC
)
2290 return def
.dso
->funcdescs
+ (def
.sym
- def
.dso
->syms
);
2291 return laddr(def
.dso
, def
.sym
->st_value
);
2294 int dladdr(const void *addr_arg
, Dl_info
*info
)
2296 size_t addr
= (size_t)addr_arg
;
2302 size_t besterr
= -1;
2304 pthread_rwlock_rdlock(&lock
);
2306 pthread_rwlock_unlock(&lock
);
2311 strings
= p
->strings
;
2312 nsym
= count_syms(p
);
2315 size_t idx
= (addr
-(size_t)p
->funcdescs
)
2316 / sizeof(*p
->funcdescs
);
2317 if (idx
< nsym
&& (sym
[idx
].st_info
&0xf) == STT_FUNC
) {
2318 best
= (size_t)(p
->funcdescs
+ idx
);
2319 bestsym
= sym
+ idx
;
2324 if (!best
) for (; nsym
; nsym
--, sym
++) {
2326 && (1<<(sym
->st_info
&0xf) & OK_TYPES
)
2327 && (1<<(sym
->st_info
>>4) & OK_BINDS
)) {
2328 size_t symaddr
= (size_t)laddr(p
, sym
->st_value
);
2329 if (symaddr
> addr
|| symaddr
<= best
)
2333 besterr
= addr
- symaddr
;
2334 if (addr
== symaddr
)
2339 if (best
&& besterr
> bestsym
->st_size
-1) {
2344 info
->dli_fname
= p
->name
;
2345 info
->dli_fbase
= p
->map
;
2348 info
->dli_sname
= 0;
2349 info
->dli_saddr
= 0;
2353 if (DL_FDPIC
&& (bestsym
->st_info
&0xf) == STT_FUNC
)
2354 best
= (size_t)(p
->funcdescs
+ (bestsym
- p
->syms
));
2355 info
->dli_sname
= strings
+ bestsym
->st_name
;
2356 info
->dli_saddr
= (void *)best
;
2361 hidden
void *__dlsym(void *restrict p
, const char *restrict s
, void *restrict ra
)
2364 pthread_rwlock_rdlock(&lock
);
2365 res
= do_dlsym(p
, s
, ra
);
2366 pthread_rwlock_unlock(&lock
);
2370 hidden
void *__dlsym_redir_time64(void *restrict p
, const char *restrict s
, void *restrict ra
)
2373 const char *suffix
, *suffix2
= "";
2376 /* Map the symbol name to a time64 version of itself according to the
2377 * pattern used for naming the redirected time64 symbols. */
2378 size_t l
= strnlen(s
, sizeof redir
);
2379 if (l
<4 || l
==sizeof redir
) goto no_redir
;
2380 if (s
[l
-2]=='_' && s
[l
-1]=='r') {
2384 if (l
<4) goto no_redir
;
2385 if (!strcmp(s
+l
-4, "time")) suffix
= "64";
2386 else suffix
= "_time64";
2388 /* Use the presence of the remapped symbol name in libc to determine
2389 * whether it's one that requires time64 redirection; replace if so. */
2390 snprintf(redir
, sizeof redir
, "__%.*s%s%s", (int)l
, s
, suffix
, suffix2
);
2391 if (find_sym(&ldso
, redir
, 1).sym
) s
= redir
;
2394 return __dlsym(p
, s
, ra
);
2397 int dl_iterate_phdr(int(*callback
)(struct dl_phdr_info
*info
, size_t size
, void *data
), void *data
)
2399 struct dso
*current
;
2400 struct dl_phdr_info info
;
2402 for(current
= head
; current
;) {
2403 info
.dlpi_addr
= (uintptr_t)current
->base
;
2404 info
.dlpi_name
= current
->name
;
2405 info
.dlpi_phdr
= current
->phdr
;
2406 info
.dlpi_phnum
= current
->phnum
;
2407 info
.dlpi_adds
= gencnt
;
2409 info
.dlpi_tls_modid
= current
->tls_id
;
2410 info
.dlpi_tls_data
= !current
->tls_id
? 0 :
2411 __tls_get_addr((tls_mod_off_t
[]){current
->tls_id
,0});
2413 ret
= (callback
)(&info
, sizeof (info
), data
);
2415 if (ret
!= 0) break;
2417 pthread_rwlock_rdlock(&lock
);
2418 current
= current
->next
;
2419 pthread_rwlock_unlock(&lock
);
2424 static void error_impl(const char *fmt
, ...)
2429 vdprintf(2, fmt
, ap
);
2435 __dl_vseterr(fmt
, ap
);
2439 static void error_noop(const char *fmt
, ...)