[DTrace-devel] [PATCH v2 4/6] procfs: implement d_execargs() for pr_psargs translator support

[Eugene Loh]

On 1/31/25 11:37, Kris Van Hees wrote:

> On Thu, Jan 30, 2025 at 02:22:44PM -0500, Eugene Loh wrote:
>> For
>> test/unittest/funcs/d_execargs/tst.d_execargs.d
>> test/unittest/proc/tst.pr_psargs.d
>> how about a few more arguments?  E.g.,
>> system("/bin/echo TEST abcde fghijkl");
>> (I don't have anything particular in mind that this might catch. Just trying
>> to poke a little harder.)
> Sure, although it does not really improve the testing because we are looping
> over all characters, changing '\0' into ' ', except for the last one.  If it
> works for one it works for all, but I also do not mind adding a few extra
> arguments.

Cool.  Again, I have nothing particular in mind that this would stress 
-- if it catches something, it would be something unforeseen.

Incidentally, I hadn't run proc/tst.pr_args.d.  I just tried:

*)  On ARM UEK6 (OL7 and OL8), I got
dtrace: error in dt_clause_1 for probe ID 98979 
(proc:vmlinux::exec-success): invalid address (0xfffff895fa9f) at BPF pc 934
dtrace: error in dt_clause_1 for probe ID 98979 
(proc:vmlinux::exec-success): invalid address (0xffffcb24faa0) at BPF pc 934
Maybe UEK6 is not of interest, but there you have it.  Some copyin 
thing?  I don't know.

*)  On most platforms, I got
              0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f 
0123456789abcdef
          0: 2f 62 69 6e 2f 65 63 68 6f 20 54 45 53 54 00 20 /bin/echo TEST.
         10: 54 45 53 54 00 00 00 00 00 00 00 00 00 00 00 00 
TEST............
         20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
................
         30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
................
         40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
................
I do not know where those extra chars are coming from, but the test is 
exposing itself to printing out garbage in any case.  Maybe use printf() 
instead of trace so that we do not print out the buffer past the NUL 
char (and get more compact and readable output to boot)?