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#include <elf.h>
#include <limits.h>
#include <stdint.h>
#include <string.h>
#include "libc.h"
#include "syscall.h"
#ifdef VDSO_USEFUL
#if ULONG_MAX == 0xffffffff
typedef Elf32_Ehdr Ehdr;
typedef Elf32_Phdr Phdr;
typedef Elf32_Sym Sym;
typedef Elf32_Verdef Verdef;
typedef Elf32_Verdaux Verdaux;
#else
typedef Elf64_Ehdr Ehdr;
typedef Elf64_Phdr Phdr;
typedef Elf64_Sym Sym;
typedef Elf64_Verdef Verdef;
typedef Elf64_Verdaux Verdaux;
#endif
static int checkver(Verdef *def, int vsym, const char *vername, char *strings)
{
vsym &= 0x7fff;
for (;;) {
if (!(def->vd_flags & VER_FLG_BASE)
&& (def->vd_ndx & 0x7fff) == vsym)
break;
if (def->vd_next == 0)
return 0;
def = (Verdef *)((char *)def + def->vd_next);
}
Verdaux *aux = (Verdaux *)((char *)def + def->vd_aux);
return !strcmp(vername, strings + aux->vda_name);
}
#define OK_TYPES (1<<STT_NOTYPE | 1<<STT_OBJECT | 1<<STT_FUNC | 1<<STT_COMMON)
#define OK_BINDS (1<<STB_GLOBAL | 1<<STB_WEAK | 1<<STB_GNU_UNIQUE)
void *__vdsosym(const char *vername, const char *name)
{
size_t i;
for (i=0; libc.auxv[i] != AT_SYSINFO_EHDR; i+=2)
if (!libc.auxv[i]) return 0;
Ehdr *eh = (void *)libc.auxv[i+1];
Phdr *ph = (void *)((char *)eh + eh->e_phoff);
size_t *dynv=0, base=-1;
for (i=0; i<eh->e_phnum; i++, ph=(void *)((char *)ph+eh->e_phentsize)) {
if (ph->p_type == PT_LOAD)
base = (size_t)eh + ph->p_offset - ph->p_vaddr;
else if (ph->p_type == PT_DYNAMIC)
dynv = (void *)((char *)eh + ph->p_offset);
}
if (!dynv || base==(size_t)-1) return 0;
char *strings = 0;
Sym *syms = 0;
uint32_t *hashtab = 0;
uint16_t *versym = 0;
Verdef *verdef = 0;
for (i=0; dynv[i]; i+=2) {
void *p = (void *)(base + dynv[i+1]);
switch(dynv[i]) {
case DT_STRTAB: strings = p; break;
case DT_SYMTAB: syms = p; break;
case DT_HASH: hashtab = p; break;
case DT_VERSYM: versym = p; break;
case DT_VERDEF: verdef = p; break;
}
}
if (!strings || !syms || !hashtab) return 0;
if (!verdef) versym = 0;
for (i=0; i<hashtab[1]; i++) {
if (!(1<<(syms[i].st_info&0xf) & OK_TYPES)) continue;
if (!(1<<(syms[i].st_info>>4) & OK_BINDS)) continue;
if (!syms[i].st_shndx) continue;
if (strcmp(name, strings+syms[i].st_name)) continue;
if (versym && !checkver(verdef, versym[i], vername, strings))
continue;
return (void *)(base + syms[i].st_value);
}
return 0;
}
#endif
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