elf

The pimpl idiom is commonly used in order to allow changing code in dynamically linked libraries without breaking ABI compatibility and having to recompile all the code that depends on the library. Most of the explanations I see mention that adding a new private member variable changes the offsets of public and private members in the class. That makes sense to me. What I don't understand is how in practice this actually breaks the dependent libraries. I've done a lot of reading on ELF files and how dynamic linking actually works, but I still don't see how changing the class size in the shared

Hi I am currently generating x86 assembly for a compiler that I am writing and am having some trouble linking the file on my 64-bit VM (the assembly code is 32 bit). I was able to assemble the object file fine with this command: as --32 mult.S -o mult.o but I can't seem to find any options for ld that make it generate a 32-bit ELF file: ld <some-option?> mult.o -o mult Any help would be great. Employed Russian ld <some-option?> mult.o -o mult ld -m elf_i386 mult.o -o mult You can get a list of available architectures with: ld -V Sample output: GNU ld (GNU Binutils for Ubuntu) 2.24 Supported

I developed a small cpp program on platform of Ubuntu-Linux 11.10. Now I want to reverse engineer it. I am beginner. I use such tools: GDB 7.0, hte editor, hexeditor . For the first time I made it pretty easy. With help of symbolic information I founded the address of main function and made everything I needed. Then I striped ( --strip-all ) executable elf-file and I have some problems. I know that main function starts from 0x8960 in this program. But I haven't any idea how should I find this point without this knowledge. I tried debug my program step by step with gdb but it goes into __libc

I recently discovered the linker option "-Bsymbolic-functions" in GNU ld: -Bsymbolic When creating a shared library, bind references to global symbols to the definition within the shared library, if any. Normally, it is possible for a program linked against a shared library to override the definition within the shared library. This option is only meaningful on ELF platforms which support shared libraries. -Bsymbolic-functions When creating a shared library, bind references to global function symbols to the definition within the shared library, if any. This option is only meaningful on ELF

I am trying to build a simple C program for two different Linux environments. On one device the program runs fine, on the other device the program generates a floating point exception. The program does nothing but return 0 from main which leads me to believe there is some incompatibility with the start-up code perhaps ABI? The program is compiled with gcc with the following build specs: Using built-in specs. Target: i386-redhat-linux Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --enable-checking=release -

Could someone explain the columns shown of the symbol table using readelf ? Caladain Consider the following: Symbol table .symtab contains 1203 entries: Num: Value Size Type Bind Vis Ndx Name 310: a0008120 0 NOTYPE GLOBAL DEFAULT ABS _gp 734: a0000010 32 OBJECT GLOBAL DEFAULT 77 v 818: 9d000018 496 FUNC GLOBAL DEFAULT 71 main 849: a0000124 4 OBJECT GLOBAL DEFAULT 78 phrase 955: a0000000 9 OBJECT GLOBAL DEFAULT 77 peppers 1020: a000023c 192 OBJECT GLOBAL DEFAULT 80 bins Num: = The symbol number Value = The address of the Symbol Size = The size of the symbol Type = symbol type: Func = Function,

When you build a gcc toolchain there is the possibility to build it as arm-elf or as arm-none-eabi, but what is the difference? I use the eabi today, but that is just since everyone else seem to do that... but since that is a really bad argument, it would be really nice to understand the difference. Note: This toolchain will crosscompile code for Cortex-M3 based mcu:s like the stm32. Thanks Some links : EABI: http://en.wikipedia.org/wiki/Application_binary_interface http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.subset.swdev.abi/index.html ELF: http://en.wikipedia.org/wiki