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Can I add a systemcall from a module?

April 26, 2017module

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Can I add a systemcall from a module?

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• Short answer: NO • Longer answer: In some kernel versions it is possible to add or modify a systemcall by changing the sys_call_table. But because this table is not intended to be changed at runtime, it has no protection. Changing the table will lead to race conditions. Even without the race conditions, there are problems related to removing the modules while they are in use or stacked. Because of the problems with changing sys_call_table from modules, the symbol is no longer exported in new kernels. In other words if you get “unresolved symbol sys_call_table” when trying to load a module, it means there is a bug in the module, and the kernel does no longer accept such buggy modules. • Can I use C++ code in the kernel and modules? No, read more in the kernel mailing list FAQ. Can I save and restore the state of a process? http://freshmeat.net/projects/condor/?topic_id=150%2C141 http://www.cs.columbia.edu/~huaz/english/research/crak.htm http://www.checkpointing.org/ swsusp http://www.