Should we trust on LD_PRELOAD (library preload) ?

barunparichha · 07-12-2006, 12:44 PM

i have been using preloading concept for some time, but what i found is quite surprising. e.g let's talk about open() system calll. If you are going to overload this then you should also overload __open() as it's called by fopen(). But even after doing all these overloading, i am just able to overload a subset of open() calls practally. When i tested this overloading business with cat it works fine whereas for vi it fails.
I don't know what's the problem ?
With thanks in advance,

jtshaw · 07-12-2006, 02:44 PM

Moved: This thread is more suitable in Programming and has been moved accordingly to help your thread/question get the exposure it deserves.

primo · 07-13-2006, 09:42 PM

Quote:

Originally Posted by barunparichha

i have been using preloading concept for some time, but what i found is quite surprising. e.g let's talk about open() system calll. If you are going to overload this then you should also overload __open() as it's called by fopen(). But even after doing all these overloading, i am just able to overload a subset of open() calls practally. When i tested this overloading business with cat it works fine whereas for vi it fails.
I don't know what's the problem ?
With thanks in advance,

First check vi is dinamically linked with ldd(1), then try with ltrace(8)/strace(8) to see the syscalls involved. vi is usually linked statically as it's the basic editor but it depends on the OS.