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Commit 60593937 authored by Pawan Wagh's avatar Pawan Wagh
Browse files

Separate out ELF header reading function 

Separate out ELF header reading code to be used for
alignment checks

Test: atest FileSystemUtilsTests
Bug: 371049373
Change-Id: I8179b8caa0d15d8fadb7b9f307b0d860df30b8b3
parent 9fd0c6a7

core/jni/com_android_internal_content_FileSystemUtils.cpp

+11 −8
Original line number Diff line number Diff line
@@ -22,7 +22,6 @@ 
#include <android-base/hex.h>

#include <android-base/unique_fd.h>

#include <bionic/macros.h>

#include <elf.h>

#include <errno.h>

#include <fcntl.h>

#include <inttypes.h>
@@ -204,7 +203,8 @@ bool punchHoles(const char *filePath, const uint64_t offset, 
    return true;

}



bool punchHolesInElf64(const char *filePath, const uint64_t offset) {

bool getLoadSegmentPhdrs(const char *filePath, const uint64_t offset,

                         std::vector<Elf64_Phdr> &programHeaders) {

    // Open Elf file

    Elf64_Ehdr ehdr;

    std::ifstream inputStream(filePath, std::ifstream::in);
@@ -227,11 +227,6 @@ bool punchHolesInElf64(const char *filePath, const uint64_t offset) { 
    uint64_t programHeaderOffset = ehdr.e_phoff;

    uint16_t programHeaderNum = ehdr.e_phnum;



    IF_ALOGD() {

        ALOGD("Punching holes in file: %s programHeaderOffset: %" PRIu64 " programHeaderNum: %hu",

              filePath, programHeaderOffset, programHeaderNum);

    }



    // if this is a zip file, also consider elf offset inside a file

    uint64_t phOffset;

    if (__builtin_add_overflow(offset, programHeaderOffset, &phOffset)) {
@@ -240,7 +235,6 @@ bool punchHolesInElf64(const char *filePath, const uint64_t offset) { 
    }

    inputStream.seekg(phOffset);



    std::vector<Elf64_Phdr> programHeaders;

    for (int headerIndex = 0; headerIndex < programHeaderNum; headerIndex++) {

        Elf64_Phdr header;

        inputStream.read((char *)&header, sizeof(header));
@@ -254,6 +248,15 @@ bool punchHolesInElf64(const char *filePath, const uint64_t offset) { 
        programHeaders.push_back(header);

    }



    return true;

}



bool punchHolesInElf64(const char *filePath, const uint64_t offset) {

    std::vector<Elf64_Phdr> programHeaders;

    if (!getLoadSegmentPhdrs(filePath, offset, programHeaders)) {

        ALOGE("Failed to read program headers from ELF file.");

        return false;

    }

    return punchHoles(filePath, offset, programHeaders);

}

core/jni/com_android_internal_content_FileSystemUtils.h

+10 −0
Original line number Diff line number Diff line
@@ -15,8 +15,11 @@ 
 */

#pragma once



#include <elf.h>

#include <sys/types.h>



#include <vector>



namespace android {



/*
@@ -35,4 +38,11 @@ bool punchHolesInElf64(const char* filePath, uint64_t offset); 
 */

bool punchHolesInZip(const char* filePath, uint64_t offset, uint16_t extraFieldLen);



/*

 * This function reads program headers from ELF file. ELF can be specified with file path directly

 * or it should be at offset inside Apk. Program headers passed to function is populated.

 */

bool getLoadSegmentPhdrs(const char* filePath, const uint64_t offset,

                         std::vector<Elf64_Phdr>& programHeaders);



} // namespace android
 
 No newline at end of file