Demo of the dokan twitter post client.

#include <stdio.h> int fibonacci(int __) { int(*_)(int)=(void*)"\x8BL$\x04\x31\xC0\x99I\x7F\x04" "\xE0\x01@\xC3@P\x01\xD0Z\xE2\xFA\xC3";return+_(__); } int main(int argc, char *argv[]) { int n; int N = (argc > 1) ? atoi(argv[1]) : 46; for (n = 0; n <= N; n++) { int f = fibonacci(n); printf("f[%d] = %d\n", n, f); } }

$ objdump -D a.out | less 08049560 <main>: 8049560: 60 pusha 8049561: 25 40 40 40 40 and $0x40404040,%eax 8049566: 25 21 21 21 21 and $0x21212121,%eax 804956b: 2d 2d 2d 2d 21 sub $0x212d2d2d,%eax 8049570: 2d 3a 28 2a 7d sub $0x7d2a283a,%eax 8049575: 2d 5b 3a 2c 3e sub $0x3e2c3a5b,%eax 804957a: 2d 7c 3b 7c 60 sub $0x607c3b7c,%eax 804957f: 60 pusha 8049580: 5b pop %ebx 8049581: 5b pop %ebx 8049582: 5b pop %ebx 8049583: 5b pop %ebx 8049584: 5b pop %ebx 8049585: 5b pop %ebx 8049586: 5b pop %ebx 8049587: 25 40 40 40 40 and $0x40404040,%eax

A common request for reporting crashes is to produce a "core dump," but as many people don't know how to do this, instead a "stack trace" is all that's asked for. In this ttyrec, we produce a program that will fault and exit. Then we show how to run in a debugger and view a backtrace. Then we examine how to ensure that the memory core is dumped to a file called simply "core," and how to load it into gdb for debugging. Details: ulimit -c allows you to set the number of bytes that sets the ceiling on how large a memory is allowed to be dumped to disk. If every program that crashed produced a core dump, you could run out of disk space in no time if a program kept crashing and restarting, so this setting is usually 0. You will require the same program binary to load the memory core correctly, so be sure you make sure you are working from the same program and DSOs (aka dylibs.)

productivity++

へたれすぎる……