Add helper to check if ftrace is enabled

[grantseltzer]

Signed-off-by: grantseltzer grantseltzer@gmail.com

[rafaeldtinoco]

LGTM

[mtcherni95]

why not just use TrimSpace and compare it? don't we also want to report the error instead of just a boolean?

[rafaeldtinoco]

why not just use TrimSpace and compare it? don't we also want to report the error instead of just a boolean?

I thought you had agreed already on this helper (when I saw your other PR). Whatever you both prefer I'm good, its a simple change.

[mtcherni95]

in the other pr I implemented what I suggested above - we can use return both bool and error IMO.

[rafaeldtinoco]

in the other pr I implemented what I suggested above - we can use return both bool and error IMO.

@mtcherni95 and @yanivagman , I dont recall what we've agreed in last weeks discussion. Was it to be placed in libbpfgo or tracee ? I recall it could have been agreed to be added to tracee because libbpf did not have that check, but I could be wrong.

[mtcherni95]

in the other pr I implemented what I suggested above - we can use return both bool and error IMO.

@mtcherni95 and @yanivagman , I dont recall what we've agreed in last weeks discussion. Was it to be placed in libbpfgo or tracee ? I recall it could have been agreed to be added to tracee because libbpf did not have that check, but I could be wrong.

You are right - we agreed it would have been in tracee. However, after some further thinking it is better to have it in libbpgo and tracee will use the new API of FtraceEnabled

[grantseltzer]

why not just use TrimSpace and compare it? don't we also want to report the error instead of just a boolean?

Agreed, changed accordingly

[rafaeldtinoco]

would you mind squashing the changes into a single commit and addressing issue from my comment ? this way we can move on and merge this. thanks!

[rafaeldtinoco]

LGTM:

$ echo 0 | sudo tee /proc/sys/kernel/ftrace_enabled
0
$ go run temp.go
false <nil>
$ echo 1 | sudo tee /proc/sys/kernel/ftrace_enabled
1
$ go run temp.go
true <nil>

and simulating an error

$ go run temp.go
false could not read from ftrace_enabled file: open /proc/sys/kernel/ftrace_enabled: no such file or directory