I'm trying to build the example at this gist on OSX 10.9:
cd /tmp
git clone https://gist.github.com/ecfd80885b9ddf6734192c056cf48bf4.git fopentest
cd fopentest
bash buildrun.sh
The build succeeds - and furthermore, I can see the following in the terminal output:
...
+ DYLD_BIND_AT_LAUNCH=YES
+ ./fopentest.exe ./mytestfile.txt
This is a wrapper function for fopen.
=== this is mytestfile.txt ===
Second line here...
Third line here...
That would mean that the call DYLD_BIND_AT_LAUNCH=YES ./fopentest.exe ./mytestfile.txt
successfully found the wrapper library and function.
Now, just as a test, I'd like to run this executable through dtruss
, OSX “strace” equivalent - I've also done sudo chmod u+s /usr/sbin/dtrace
as recommmended in that link. So I try in the /tmp
folder:
$ DYLD_BIND_AT_LAUNCH=YES dtruss ./fopentest.exe ./mytestfile.txt 2>&1 | grep wrap
This is a wrapper function for fopen.
stat64("libwrapper.dylib\0", 0x7FFF5A7DF248, 0x7FFF5A7E00E0) = 0 0
open("libwrapper.dylib\0", 0x0, 0x0) = 3 0
write_nocancel(0x1, "This is a wrapper function for fopen.\n=== this is mytestfile.txt ===\nSecond line here...\nThird line here...\n\0", 0x6C) = 108 0
So, clearly dtruss
here works. However, I have the exact same files in a different directory, and why I try to run the same commands, dtruss
fails:
$ DYLD_BIND_AT_LAUNCH=YES dtruss ./fopentest.exe ./mytestfile.txt 2>&1 | grep wrap
dyld: Library not loaded: libwrapper.dylib
stat64("libwrapper.dylib\0", 0x7FFF4FD85228, 0x7FFF4FD860C0) = 0 0
open("libwrapper.dylib\0", 0x0, 0x0) = -1 Err#2
stat64("/Users/MYNAME/lib/libwrapper.dylib\0", 0x7FFF4FD85A08, 0x7FFF4FD860C0) = -1 Err#2
stat64("/usr/local/lib/libwrapper.dylib\0", 0x7FFF4FD85A08, 0x7FFF4FD860C0) = -1 Err#2
stat64("/usr/lib/libwrapper.dylib\0", 0x7FFF4FD85A18, 0x7FFF4FD860C0) = -1 Err#2
What could possibly be the reason for this?