[[!summary chatGPT: This posting shows how to alter certain functions in a library to fix issues with the date function in GCC timestamps. A code snippet is provided to create a custom memcpy function to bypass a specific issue in Adobe Flash.]]
[[!meta date="2011-05-10 09:45"]]
[[!tag linux]]

# motivation
this posting shows how to alter certain functions in a library. it might be of interest to fix some issues i found in an earlier posting where i wanted to 'fix' the date function to force GCC timestamps to be always the same date. still i think the better way of doing so is to add a new function to GCC which gives the user the freedom to fix the date to a constant, maybe by something like this:

    GCC_DATE="Tue May 10 11:37:44 CEST 2011" gcc -c main.c -o main.o

anyway here is the code written by linus and other [kernel] developers, i quote the whole posting #55 from Magnus Glantz:

# the memcpy(...) function:


I'm sure thousands of people will find their way here, so, here's a quicky. To
bypass this issue (which is an issue in Adobe Flash), you may run the below
"fix" brought forth in comment #38


## 1. Cut and paste this into a prompt:


    ---Cut below---
    cat > $HOME/Downloads/linusmemcpy.c <<EOF
    #include <sys/types.h>
    
    void *memcpy(void *dst, const void *src, size_t size)
    {
    void *orig = dst;
    asm volatile("rep ; movsq"
    :"=D" (dst), "=S" (src)
    :"0" (dst), "1" (src), "c" (size >> 3)
    :"memory");
    asm volatile("rep ; movsb"
    :"=D" (dst), "=S" (src)
    :"0" (dst), "1" (src), "c" (size & 7)
    :"memory");
    return orig;
    }
    EOF
    cd $HOME/Downloads
    gcc -O2 -c linusmemcpy.c
    ld -G linusmemcpy.o -o linusmemcpy.so
    ---Stop cutting here---


## 2. Shutdown any running copies of your webbrowser.




## 3. Until a Adobe has fixed their Flash player, start your webbrowser as below:


For Firefox users:

    LD_PRELOAD=$HOME/Downloads/linusmemcpy.so /usr/bin/firefox &

For Google Chrome users:

    LD_PRELOAD=$HOME/Downloads/linusmemcpy.so /opt/google/chrome/google-chrome &

# links

* [1] <https://bugzilla.redhat.com/show_bug.cgi?id=638477>