bpftrace should be able to list uprobe probes

[tyroguru]

Currently we have to use objdump (or something similar) to discover what functions are available to attempt to instrument with uprobes. i.e.,:

# objdump -T /proc/2398893/exe |grep -i text |more
00000000029d8d60 g    DF .text  0000000000000027  Base        xdr_u_long
0000000002b0b8b0 g    DF .text  00000000000001f6  Base        malloc_usable_size
00000000029e22a0 g    DF .text  000000000000012e  Base        _seterr_reply
00000000029dae60 g    DF .text  000000000000009f  Base        xdrrec_endofrecord
00000000029da0c0 g    DF .text  00000000000000cb  Base        xdr_longlong_t
00000000029db840 g    DF .text  000000000000008d  Base        key_setsecret
00000000029e1ce0 g    DF .text  00000000000000a6  Base        xdr_rmtcallres

bpftrace should be able to do this directly for us with a bpftrace -l /path/to/binary or bpftrace -l -p <pid>. The -p invocation now gives us usdt probes available in that process but not uprobes (actually it currently provides kprobes/software/others and I don't think it should do that with the -p option).