Messages in this thread |  | | | From | Denys Vlasenko <> | | Subject | Re: [PATCH 2/5] ptrace: implement PTRACE_SEIZE | | Date | Sat, 18 Jun 2011 09:59:38 +0200 |
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On Saturday 18 June 2011 09:55, Denys Vlasenko wrote: > On Tuesday 14 June 2011 11:20, Tejun Heo wrote: > #define PTRACE_EVENT_FORK 1 > #define PTRACE_EVENT_VFORK 2 > #define PTRACE_EVENT_CLONE 3 > > #define PTRACE_EVENT_EXEC 4 > > #define PTRACE_EVENT_VFORK_DONE 5 > > #define PTRACE_EVENT_EXIT 6 > > +#define PTRACE_EVENT_STOP 7 > > Er... these constants were corresponding exactly to > bit positions in ptrace options which enable them: > > #define PTRACE_O_TRACESYSGOOD 0x00000001 > #define PTRACE_O_TRACEFORK 0x00000002 > #define PTRACE_O_TRACEVFORK 0x00000004 > #define PTRACE_O_TRACECLONE 0x00000008 > #define PTRACE_O_TRACEEXEC 0x00000010 > #define PTRACE_O_TRACEVFORKDONE 0x00000020 > #define PTRACE_O_TRACEEXIT 0x00000040 > > For example, PTRACE_O_TRACEEXEC is 4th bit, PTRACE_EVENT_EXEC is 4. > > If we'd define PTRACE_EVENT_STOP as 7, any future added > PTRACE_O_foo bit with value 0x00000080 will be unable > to follow this convention. > > I propose to define PTRACE_EVENT_STOP as 64 instead, leaving 64 low > PTRACE_EVENT_foo constants for possible future PTRACE_O_foo bits. > > [32 should be enough too, but I feel paranoid today :)]
...unless we plan to introduce PTRACE_O_TRACESTOP (with value 0x00000080) which enables PTRACE_INTERRUPT and stop notifications independently of PTRACE_SEIZE. Which would be very useful for e.g. strace. Then, PTRACE_EVENT_STOP indeed should be 7.
-- vda
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