Instead of depending on "sysctl" being installed, just use "grep -H" for
sysctl status reporting. Additionally report kernel version for easier
comparisons.
Signed-off-by: Kees Cook <keescook@chromium.org>
 
        setbuf(stdout, NULL);
 
+       printf("Running on:\n");
+       system("uname -a");
+
        printf("Current BPF sysctl settings:\n");
-       system("sysctl net.core.bpf_jit_enable");
-       system("sysctl net.core.bpf_jit_harden");
+       /* Avoid using "sysctl" which may not be installed. */
+       system("grep -H . /proc/sys/net/core/bpf_jit_enable");
+       system("grep -H . /proc/sys/net/core/bpf_jit_harden");
 
        if (argc > 1)
                samples = strtoull(argv[1], NULL, 0);