From the system man page, it explicitely says:
Do not use system() from a program with set-user-ID or set-group-ID privileges, because strange values for some environment variables might be used to subvert system integrity.
Since system is basically a fork and wait, it’s pretty easy to use execv instead. Here is a snippet from the goog_pam module [...]
A musical “note” is a waveform that has a certain fundamental frequency. A perfect sine wave consists only of the fundamental frequency, and sounds very “pure” or mellow, like a flute. For this project, you are to use interrupts to generate the notes of a musical scale, while at the same time using another interrupt to update a count. We will generate square waves by toggling a bit within a port on and off. Specifically, your program should play the notes from middle C to the next higher C, each of approximately one second in duration. These notes should be playing at the same time that an 8-bit binary count is being displayed in the LED’s, updating at approximately 1/4 second.
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