mach-o | 易学教程

fork Cocoa process and re-init Cocoa. how?

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问题 I tried to fork() a Cocoa process and setup a new Cocoa/ObjC environment but I get the error: The process has forked and you cannot use this CoreFoundation functionality safely. You MUST exec(). Break on __THE_PROCESS_HAS_FORKED_AND_YOU_CANNOT_USE_THIS_COREFOUNDATION_FUNCTIONALITY___YOU_MUST_EXEC__() to debug. Is there a way to re-initialize Cocoa/ObjC in the forked process? I know that the documentation about fork() does say it is limited, however I wonder if there is still a way to do it,

Position Independent Code pointing to wrong address

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问题 I have a small example program written in NASM(2.11.08) targeting the macho64 architecture. I'm running OSX 10.10.3: bits 64 section .data msg1 db 'Message One', 10, 0 msg1len equ $-msg1 msg2 db 'Message Two', 10, 0 msg2len equ $-msg2 section .text global _main extern _printf _main: sub rsp, 8 ; align lea rdi, [rel msg1] xor rax, rax call _printf lea rdi, [rel msg2] xor rax, rax call _printf add rsp, 8 ret I'm compiling and linking using the following command line: /usr/local/bin/nasm -f

Assembler Error: Mach-O 64 bit does not support absolute 32 bit addresses

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So I'm learning x86_64 nasm assembly on my mac for fun. After hello world and some basic arithmetic, I tried copying a slightly more advanced hello world program from this site and modifying it for 64 bit intel, but I can't get rid of this one error message: hello.s:53: error: Mach-O 64-bit format does not support 32-bit absolute addresses . Here is the command I use to assemble and link: nasm -f macho64 hello.s && ld -macosx_version_min 10.6 hello.o . And here is the relevant line: cmp rsi, name+8 rsi is the register I am using for my index in the loop, and name is a quad word reserved for

What is required for a Mach-O executable to load?

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I am attempting to hand-write a Mach-O executable. There are three load commands: LC_SEGMENT_64 loading __PAGEZERO LC_SEGMENT_64 loading __TEXT , with a single __text section LC_UNIXTHREAD with an appropriately-set rip Every command matches the structs in mach/loader.h and related headers. otool -l lists the information as expected and doesn't report any errors. By all accounts it is a well-formed object file — yet OS X 10.10.5 terminates the task (SIGKILL). What features of a Mach-O executable are checked before OS X will load it? Where is this information located? Do these features change

codesign an old Director projector on OS X 10.13 - perhaps manipulate __LINKEDIT segment value

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问题 (See Updates at end of this post) For $reasons, I need to codesign an old Director projector that we can no longer re-publish (no access to original source code or to Director). I'm doing this because when run without being signed, the app now opens a Finder window with a prompt saying "Where is..." asking for a file that's one of the embedded projector resources. But... If I cd into the Projector.app contents (it's not really called that, but you get the idea) and find the projector binary

Basic OS X Assembly and the Mach-O format

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问题 I am interested in programming in x86-64 assembly on the Mac OS X platform. I came across this page about creating a 248B Mach-O program, which led me to Apple's own Mach-O format reference. After that I thought I'd make that same simple C program in Xcode and check out the generated assembly. This was the code: int main(int argc, const char * argv[]) { return 42; } But the assembly generated was 334 lines, containing (based on the 248B model) a lot of excess content. Firstly, why is so much

Apple Mach-O Linker errors and I don't know what to do

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I cannot compile my project for the device or simulator anymore. I get 13 Apple Mach-O-Linker errors. It all started after I failed attempt to use sharekit. Here is the log from the error: ld: warning: directory not found for option '-F/Users/bbrandy95/Documents/Broken Brandsonic Web Projects/Brandsonic Web mobile/../../Downloads/0.2.1gm1/iphoneos4.0/System/Library/Frameworks' Undefined symbols for architecture armv7: "_OBJC_CLASS_$_NSURLRequest", referenced from: objc-class-ref in Brandsonic_Web_mobileAppDelegate.o objc-class-ref in Brandsonic_Web_mobileViewController.o "_OBJC_CLASS_$

What is required for a Mach-O executable to load?

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问题 I am attempting to hand-write a Mach-O executable. There are three load commands: LC_SEGMENT_64 loading __PAGEZERO LC_SEGMENT_64 loading __TEXT , with a single __text section LC_UNIXTHREAD with an appropriately-set rip Every command matches the structs in mach/loader.h and related headers. otool -l lists the information as expected and doesn't report any errors. By all accounts it is a well-formed object file — yet OS X 10.10.5 terminates the task (SIGKILL). What features of a Mach-O

Linker command error: 'ld: symbol(s) not found for architecture i386'

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I have an error at compile time. Seems to be weird. it worked as detail view application, but using single view doesn't seem to work. this is the error details: Undefined symbols for architecture i386: "_OBJC_CLASS_$_RssArticle", referenced from: objc-class-ref in RssXmlParser.o ld: symbol(s) not found for architecture i386 clang: error: linker command failed with exit code 1 (use -v to see invocation) iOS Test Try these steps: Open your project in XCode. In left side window/panel of XCode click on your project name on top. Now select Target from right side panel of XCode. Select Build Phases

How libgmalloc work with two level namespaces?

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问题 I want to write my own malloc/free functions with debug purposes, documentation says I have to use DYLD_FORCE_FLAT_NAMESPACE together with DYLD_INSERT_LIBRARIES. But at the same time libgmalloc article clearly states: libgmalloc is available in /usr/lib/libgmalloc.dylib. To use it, set this environment variable: set DYLD_INSERT_LIBRARIES to /usr/lib/libgmalloc.dylib Note: it is no longer necessary to set DYLD_FORCE_FLAT_NAMESPACE. The question is: how to remove the necessity in DYLD_FORCE