Reviewing changes in Linux 3.15 for anything for which glibc changes would be appropriate, I don't see how the MSA sigcontext changes are supposed to work with existing binaries.
The sigcontext structure isn't used on its own - it's part of ucontext, which is passed to signal handlers, and it's not at the end of ucontext, but followed by the signal mask. So existing binaries will expect the signal mask at a particular offset in the ucontext. As far as I can see, extending sigcontext requires a new sigaction flag that could be used to opt in, for a particular signal handler, to receiving the new-layout ucontext (so new symbol versions of sigaction in glibc could then pass that flag to the kernel, but existing binaries would continue to get old-layout ucontext from the kernel), or else putting the new data at the end of ucontext rather than in the main sigcontext structure (though I don't know if that would have other issues). -- Joseph S. Myers [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
