xref: /third_party/musl/src/ldso/dl_iterate_phdr.c (revision 570af302)
1#include <elf.h>
2#include <link.h>
3#include "pthread_impl.h"
4#include "libc.h"
5
6#define AUX_CNT 38
7
8extern weak hidden const size_t _DYNAMIC[];
9
10static int static_dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
11{
12	unsigned char *p;
13	ElfW(Phdr) *phdr, *tls_phdr=0;
14	size_t base = 0;
15	size_t n;
16	struct dl_phdr_info info;
17	size_t i, aux[AUX_CNT] = {0};
18
19	for (i=0; libc.auxv[i]; i+=2)
20		if (libc.auxv[i]<AUX_CNT) aux[libc.auxv[i]] = libc.auxv[i+1];
21
22	for (p=(void *)aux[AT_PHDR],n=aux[AT_PHNUM]; n; n--,p+=aux[AT_PHENT]) {
23		phdr = (void *)p;
24		if (phdr->p_type == PT_PHDR)
25			base = aux[AT_PHDR] - phdr->p_vaddr;
26		if (phdr->p_type == PT_DYNAMIC && _DYNAMIC)
27			base = (size_t)_DYNAMIC - phdr->p_vaddr;
28		if (phdr->p_type == PT_TLS)
29			tls_phdr = phdr;
30	}
31	info.dlpi_addr  = base;
32	info.dlpi_name  = "/proc/self/exe";
33	info.dlpi_phdr  = (void *)aux[AT_PHDR];
34	info.dlpi_phnum = aux[AT_PHNUM];
35	info.dlpi_adds  = 0;
36	info.dlpi_subs  = 0;
37	if (tls_phdr) {
38		info.dlpi_tls_modid = 1;
39		info.dlpi_tls_data = __tls_get_addr((tls_mod_off_t[]){1,0});
40	} else {
41		info.dlpi_tls_modid = 0;
42		info.dlpi_tls_data = 0;
43	}
44	return (callback)(&info, sizeof (info), data);
45}
46
47weak_alias(static_dl_iterate_phdr, dl_iterate_phdr);
48