Why does it happen? Let's exclude the possible software crash problem, and the file is OK. The possible error message reason could be because even seemingly identical files may have different internal structures. ScPTGv : Read-only file system. As it turns out, the root of my problems was a bad quality electricity input to my desktop. It caused damage almost everywhere inside my root partition and this was the only side effect I could detect at first. The big clue was when everything stopped working after a complete format while compiling from one of the ttys.
No logs or segfaults, nothing. If it's not one thing is the other. Guys, I know this thread is 8 years old but it saved my back just now in I owe everyone beer. You must log in or register to reply here.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register. The text was updated successfully, but these errors were encountered:. There's definitely some support for ARM there - we have arm files for the readelf comparison tests; but maybe this particular functionality is not supported applying relocations in dwarf.
Patches welcome! Sorry, something went wrong. How can I add test cases to compare output with readelf? Skip to content. This page or section is a work in progress and may thus be incomplete. Its content may be changed in the near future. This tutorial describes the steps to loading ELF files targeting the i bit architecture, little-endian byte order. It may later be expanded to cover other types of ELF files, or formats targeting other architectures or machine types. The ELF file format is made to function on a number of different architectures, many of which support different data widths.
For support across multiple machine types, the ELF format provides a set of guidelines for fixed width types that make up the layout of the section and data represented within object files. You may choose to name your types differently or use types defined in stdint. The format itself is extremely flexible as the positioning, size, and purpose of every header save the ELF header is described by another header in the file.
The ELF header is the first header in an ELF file and it provides important information about the file such as the machine type, architecture and byte order, etc. The ELF header also provides information about other sections in the file, since they can appear in any order, vary in size, or may be absent from the file altogether.
Universal to all ELF files are the first 4 bytes the magic number which are used identify the file. The first field in the header consists of 16 bytes, many of which provide important information about the ELF file such as the intended architecture, byte order, and ABI information.
Since this tutorial focuses on implementing an x86 compatible loader, only relevant value definitions have been included.
The file header also provides information about the machine type and file type. Once again, only the relevant definitions have been included above. Before an ELF file can be loaded, linked, relocated or otherwise processed, it's important to ensure that the machine trying to perform the aforementioned is able to do.
This entails that the file is a valid ELF file targeting the local machine's architecture, byte order and CPU type, and that any operating system specific semantics are satisfied. Assuming that an ELF file has already been loaded into memory either by the bootloader or otherwise , the first step to loading an ELF file is checking the ELF header for the magic number that should be present at the begining of the file.
A minimal implementation of this could simply treat the image of file in memory as a string and do a comparison against a predefined string. In the example above, the comparision is done byte by byte through the ELF header type, and provides detailed feedback when the method encounters an error. The next step to loading an ELF object is to check that the file in question is intended to run on the machine that has loaded it.
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