Messages in this thread | | | Date | Fri, 22 Jun 2001 13:31:02 -0700 | From | george anzinger <> | Subject | Re: signal dequeue ... |
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Davide Libenzi wrote: > > On 22-Jun-2001 george anzinger wrote: > > Davide Libenzi wrote: > >> > >> I'm just trying to figure out the reason why signal must be delivered one at > >> a > >> time instead of building a frame with multiple calls with only the last one > >> chaining back to the kernel. > >> All previous calls instead of calling the stub that jump back to the kernel > >> will call a small stub like ( Ix86 ) : > >> > >> stkclean_stub: > >> add $frame_size, %esp > >> cmp %esp, $end_stubs > >> jae $sigreturn_stub > >> ret > >> sigreturn_stub: > >> mov __NR_sigreturn, %eax > >> int $0x80 > >> end_stubs: > >> > >> ... > >> | context1 > >> * $stkclean_stub > >> * sigh1_eip > >> | context0 > >> * $stkclean_stub > >> * sigh0_eip > >> > >> When sigh0 return, it'll call stkclean_stub that will clean context0 and if > >> we're at the end it'll call the jump-back-to-kernel stub, otherwise the > >> it'll > >> execute the ret the will call sigh1 handler ... and so on. > >> > > And if the user handler does a long_jmp? > > But if the user handler does a long_jump even the old stub will be missed, > isn't it ?
Right, but the remaining signals are still pending. In your method, the kernel doesn't know which were and which were not actually delivered.
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