procstat: Add a 'compartments' command to list c18n compartments #2276
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Co-authored-by: Dapeng Gao <dapeng.gao@cl.cam.ac.uk>
| struct cheri_c18n_compart { | ||
| ssize_t ccc_id; | ||
| char ccc_name[CHERI_C18N_COMPART_MAXNAME]; | ||
| char _ccc_pad[64]; /* Shrink as new fields added above. */ |
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I wonder if we should preemptively define a 'ccc_flags' field to capture concepts like "This is a non-default sub-library compartment", "this compartment can performance system calls", and similar?
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I think we can always add them in the future when they become needed. Right now RTLD doesn't track such information about compartments, so it is risky to to add the flags prematurely.
| */ | ||
| if (len != sizeof(info) || | ||
| info.version != CHERI_C18N_INFO_VERSION || | ||
| info.comparts_gen % 2 != 0 || |
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I somewhat wondered if we wanted some sort of memory-barrier arrangement to ensure that we got a clean(ish) snapshot -- i.e., that if we saw the current generation, we saw all the stores we read from the compartment / string tables came before the generation number we read was stored, and that at the end of the sysctl function we haven't seen any stores that post-dated that generation-number store?
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Every iteration below we also re-read the generation number and check that it hasn’t changed. Presumably this achieves the desired effect?
| return; | ||
| } | ||
| if ((procstat_opts & PS_OPT_NOHEADER) == 0) | ||
| xo_emit("{T:/%5s %-19s %4s %-40s}\n", "PID", "COMM", "CID", |
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I always feel that 19 characters wide is quite a long slot for COMM, which most of the time uses list. Not sure if other procstat/ps modes might give less by default?
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I think 19 is fine (in fact it is too short for the cheribsdtest variants). And the existing c18n and cheri commands both use 19.
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I widened to 19 (MAXCOMLEN) for auxv in 64e9f6a. It can be shorter, but it should probably the right most column so it can safely spill if it's not going to be MAXCOMLEN.
| @@ -47,6 +53,8 @@ | |||
| .Nm procstat_getargv , | |||
| .Nm procstat_getauxv , | |||
| .Nm procstat_getenvv , | |||
| .Nm procstat_getc18n , | |||
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Documenting this is good, but it should be a separate commit.
| return; | ||
| } | ||
| if ((procstat_opts & PS_OPT_NOHEADER) == 0) | ||
| xo_emit("{T:/%5s %-19s %4s %-40s}\n", "PID", "COMM", "CID", |
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I widened to 19 (MAXCOMLEN) for auxv in 64e9f6a. It can be shorter, but it should probably the right most column so it can safely spill if it's not going to be MAXCOMLEN.
This rebases #2272 to dev and adds more features (incl. a generation counter for the compartment array to deal with races).