Doesn't popen() pass strings to a shell? Sounds dangerous, as you would have to escape semicolons, quotes, etc.

I might be wrong but I think it's about censoring the 'hell' in 'shell'. Because some parts of the world consider words like 'hell' and 'damn' to be profane.

Hold on, what? Okay, return false if they aren't equal, then open another process to repeat this method once again in the shell... I can't guess the reason. Would you know if there is any reason this might have been done?

I wouldn't know the real reason for sure, but this seems plausible:

1) They got tired of having to modify C code and wait for the deploy cycle to modify the filter

2) Using, for example, the database would be more work than calling a shell script. On top of that, it might actually be beyond the abilities of the programmer involved.

3) The C code executes on an arbitrary machine. Hence the ssh to a specific machine, so that the shell script would only have to be maintained in one place

strcmp returns 0 if the strings are equal.