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#include <elf.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "glibc.h"
#include "features.h"
namespace {
void ReadAuxVector(Elf64_auxv_t** begin, Elf64_auxv_t** end) noexcept {
int fd = open("/proc/self/auxv", O_RDONLY | O_CLOEXEC);
if (fd == -1) {
return;
}
constexpr size_t item_size = sizeof(Elf64_auxv_t);
constexpr size_t block_size = item_size * 32;
size_t bytes_read = 0;
size_t size = 0;
struct TBuffer {
~TBuffer() {
free(Pointer);
}
char* Pointer = nullptr;
} buffer;
while (true) {
size_t bytes_left = size - bytes_read;
if (!bytes_left) {
size += block_size;
char* new_buffer = (char*)realloc(buffer.Pointer, size);
if (!new_buffer) {
return;
}
buffer.Pointer = new_buffer;
continue;
}
ssize_t r = read(fd, buffer.Pointer + bytes_read, bytes_left);
if (!r) {
break;
} else if (r < 0) {
if (errno == EINTR) {
continue;
} else {
return;
}
}
bytes_read += r;
}
size_t item_count = bytes_read / item_size;
*begin = (Elf64_auxv_t*)buffer.Pointer;
*end = (Elf64_auxv_t*)(buffer.Pointer + item_count * item_size);
buffer.Pointer = nullptr;
}
}
extern "C" {
weak unsigned long __getauxval(unsigned long item);
}
namespace NUbuntuCompat {
TGlibc::TGlibc() noexcept
: AuxVectorBegin(nullptr)
, AuxVectorEnd(nullptr)
{
if (!__getauxval) {
ReadAuxVector((Elf64_auxv_t**)&AuxVectorBegin, (Elf64_auxv_t**)&AuxVectorEnd);
}
Secure = (bool)GetAuxVal(AT_SECURE);
}
TGlibc::~TGlibc() noexcept {
free(AuxVectorBegin);
}
unsigned long TGlibc::GetAuxVal(unsigned long item) noexcept {
if (__getauxval) {
return __getauxval(item);
}
for (Elf64_auxv_t* p = (Elf64_auxv_t*)AuxVectorBegin; p < (Elf64_auxv_t*)AuxVectorEnd; ++p) {
if (p->a_type == item) {
return p->a_un.a_val;
}
}
errno = ENOENT;
return 0;
}
bool TGlibc::IsSecure() noexcept {
return Secure;
}
static TGlibc __attribute__((__init_priority__(101))) GlibcInstance;
TGlibc& GetGlibc() noexcept {
return GlibcInstance;
}
}
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