Remove preprocessor directives and associated code,

that tie runtime behavior to compilation environment,
which is the wrong thing to do.

src/tracee/event.c

@@ -637,7 +637,6 @@ int handle_tracee_event_kernel_4_8(Tracee *tracee, int tracee_status)
 int handle_tracee_event(Tracee *tracee, int tracee_status)
 {
 	static bool seccomp_detected = false;
-	static bool seccomp_enabled = false;
 	long status;
 	int signal;
 
@@ -710,7 +709,6 @@ int handle_tracee_event(Tracee *tracee, int tracee_status)
 			status = ptrace(PTRACE_SETOPTIONS, tracee->pid, NULL,
 					default_ptrace_options | PTRACE_O_TRACESECCOMP);
 			if (status < 0) {
-                seccomp_enabled = false;
 				/* ... otherwise use default options only.  */
 				status = ptrace(PTRACE_SETOPTIONS, tracee->pid, NULL,
 						default_ptrace_options);
@@ -719,50 +717,8 @@ int handle_tracee_event(Tracee *tracee, int tracee_status)
 					exit(EXIT_FAILURE);
 				}
 			}
-            else {
-                if (getenv("PROOT_NO_SECCOMP") == NULL)
-                    seccomp_enabled = true;
-            }
 		}
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,8,0)
-
-			/* Fall through. */
-		case SIGTRAP | PTRACE_EVENT_SECCOMP2 << 8:
-		case SIGTRAP | PTRACE_EVENT_SECCOMP << 8:
-
-            if (!seccomp_detected && seccomp_enabled) {
-                VERBOSE(tracee, 1, "ptrace acceleration (seccomp mode 2) enabled");
-                tracee->seccomp = ENABLED;
-                seccomp_detected = true;
-            }
-
-            if (signal == (SIGTRAP | PTRACE_EVENT_SECCOMP2 << 8) ||
-                    signal == (SIGTRAP | PTRACE_EVENT_SECCOMP << 8)) {
-
-                unsigned long flags = 0;
-                signal = 0;
-
-                /* SECCOMP TRAP can only be received for
-                 * sysenter events, ignore otherwise */
-                if (!IS_IN_SYSENTER(tracee)) {
-                    tracee->restart_how = PTRACE_CONT;
-                    return 0;
-                    }
-                status = ptrace(PTRACE_GETEVENTMSG, tracee->pid, NULL, &flags);
-                if (status < 0)
-                    break;
-
-                if (tracee->seccomp == ENABLED && (flags & FILTER_SYSEXIT) == 0) {
-                    tracee->restart_how = PTRACE_CONT;
-                    translate_syscall(tracee);
-
-                    if (tracee->seccomp == DISABLING)
-                        tracee->restart_how = PTRACE_SYSCALL;
-                    break;
-                }
-            }
-#endif
 			/* Fall through. */
 		case SIGTRAP | 0x80:
 			signal = 0;
@@ -812,8 +768,6 @@ int handle_tracee_event(Tracee *tracee, int tracee_status)
 			}
 			break;
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(4,8,0)
-
 		case SIGTRAP | PTRACE_EVENT_SECCOMP2 << 8:
 		case SIGTRAP | PTRACE_EVENT_SECCOMP << 8: {
 			unsigned long flags = 0;
@@ -855,8 +809,6 @@ int handle_tracee_event(Tracee *tracee, int tracee_status)
 			break;
 		}
 
-#endif
-
 		case SIGTRAP | PTRACE_EVENT_VFORK << 8:
 			signal = 0;
 			(void) new_child(tracee, CLONE_VFORK);