Bash sample code: Memory leak test script

This is how to make a simple bash script that detects memory leak -- memory that the application has allocated, but has been lost and cannot be freed -- using any debugger tool that requires installation.

Requirement: The program from which you want to detect memory leak need to be running at least 15 consecutive seconds, enough time for it to generate memory leak (or not) and to let the bash script making its job at the same time.

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Sample Code

function detect_memory_leaks
{
    local PROG_PATH=$1       # 1st argument: The path to the executable to test

    # run the executable silently and send it to background using '&'
    ($PROG_PATH >/dev/null 2>&1) &

    # get its process ID with '$!' and save it in a variable PID
    local PID=$!

    # wait for 5 seconds to let the executable generating memory leak (or not)
    sleep 5

    # check if the process is still running in background
    # if not, we cannot detect memory leak and we must stop the test
    if [ -z "$(ps a | awk -v PID=$PID '$1 == PID {print}')" ]
    then
        echo "An error occurred: The program has terminated too quickly"
        return
    fi

    # run the 'leaks' command with the process ID as argument,
    # and save the outputted line where total leaked bytes appears
    local RESULT=$(leaks $PID 2>/dev/null | grep 'total leaked bytes')

    # note: the user may be asked for his administrator password
    # that's why we need the executable to be running 15 seconds at least
    # letting the user entering his password if necessary

    # kill the executable, as we do not need it to be running anymore
    kill -9 $PID >/dev/null 2>&1

    # test if RESULT is empty
    if [ -z "$RESULT" ]
    then
        # if yes, that means the command 'leaks' has failed
        echo "An error occurred: Unable to detect memory leak"
    else
        # otherwise, display the total leaked bytes
        echo $RESULT
    fi
}

detect_memory_leaks "./ft_ls -R /Users"

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Tips

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Execute a program in background and get its process ID

(to be written)

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Difference between kill -9 and kill -15

(to be written)

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Why using process ID instead of program name

(to be written)