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Re: Finding symbols in loaded kexts

At 10:15 -0700 6/8/07, Michael Smith wrote:
On Aug 6, 2007, at 9:58 AM, Andrew Gallatin wrote: 
If the symbol is not global, but still present, would it work to call
it via a function pointer initialized to the correct address?  Eg,
does the "global" property mean anything once the module is relocated?

All that "global" means is that it's available to modules linking with it, in this context.

Actually... you have to be careful about this, at least on Intel 32-bit, at least in user space. If you declare a function to be "static", the compiler knows all of the callers and is free to adjust the parameter passing to its own ends. I've seen this happen on Intel 32-bit, where the compiler decides to ignore the standard calling conventions and pass some parameters in registers. Calling such a function via a function pointer (or, indeed, from GDB, which is how I tripped over this) is a way to a dusty (and confusing) death.

S+E
--
Quinn "The Eskimo!"                    <http://www.apple.com/developer/>
Apple Developer Relations, Developer Technical Support, Core OS/Hardware
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References: 
 >Finding symbols in loaded kexts (From: Ryan Govostes <email@hidden>)
 >Re: Finding symbols in loaded kexts (From: Dean Reece <email@hidden>)
 >Re: Finding symbols in loaded kexts (From: Andrew Gallatin <email@hidden>)
 >Re: Finding symbols in loaded kexts (From: Michael Smith <email@hidden>)



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