minecraft-pi-docker/launcher/src/patchelf.cpp

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#include <cstdlib>
#include <sys/stat.h>
#include <LIEF/ELF.hpp>
#include <libreborn/libreborn.h>
#include "patchelf.h"
// Duplicate MCPI Executable Into /tmp
static void duplicate_mcpi_executable(char *new_path) {
// Ensure Temporary Directory
{
// Check If It Exists
struct stat tmp_stat;
int exists = stat(MCPI_PATCHED_DIR, &tmp_stat) != 0 ? 0 : S_ISDIR(tmp_stat.st_mode);
if (!exists) {
// Doesn't Exist
if (mkdir(MCPI_PATCHED_DIR, S_IRUSR | S_IWUSR | S_IXUSR) != 0) {
ERR("Unable To Create Temporary Folder: %s", strerror(errno));
}
}
}
// Generate New File
int new_file_fd = mkstemp(new_path);
if (new_file_fd == -1) {
ERR("Unable To Create Temporary File: %s", strerror(errno));
}
close(new_file_fd);
}
// Fix MCPI Dependencies
static const char *libraries_to_remove[] = {
"libbcm_host.so",
"libX11.so.6",
"libEGL.so",
"libGLESv2.so",
"libSDL-1.2.so.0"
};
static const char *libraries_to_add[] = {
"libmedia-layer-core.so"
};
void patch_mcpi_elf_dependencies(const char *original_path, char *new_path, const char *linker) {
// Duplicate MCPI executable into /tmp so it can be modified.
duplicate_mcpi_executable(new_path);
// Patch File
{
std::unique_ptr<LIEF::ELF::Binary> binary = LIEF::ELF::Parser::parse(original_path);
if (linker != NULL) {
binary->interpreter(linker);
}
for (size_t i = 0; i < (sizeof (libraries_to_remove) / sizeof (const char *)); i++) {
binary->remove_library(libraries_to_remove[i]);
}
for (size_t i = 0; i < (sizeof (libraries_to_add) / sizeof (const char *)); i++) {
binary->add_library(libraries_to_add[i]);
}
LIEF::ELF::Builder builder{*binary};
builder.build();
builder.write(new_path);
}
// Fix Permissions
if (chmod(new_path, S_IRUSR | S_IXUSR) != 0) {
ERR("Unable To Set File Permissions: %s: %s", new_path, strerror(errno));
}
}
// Get Interpreter
static int dl_iterate_callback(struct dl_phdr_info *info, __attribute__((unused)) size_t size, void *data) {
// Only Search Current Program
if (strcmp(info->dlpi_name, "") == 0) {
for (int i = 0; i < info->dlpi_phnum; i++) {
if (info->dlpi_phdr[i].p_type == PT_INTERP) {
// Callback
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*(char **) data = (char *) (info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
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}
}
}
return 0;
}
char *patch_get_interpreter() {
char *interpreter = NULL;
dl_iterate_phdr(dl_iterate_callback, &interpreter);
if (interpreter != NULL) {
interpreter = strdup(interpreter);
}
return interpreter;
}