harden ipc and frontend recovery

bench/Makefile

@@ -1,8 +1,8 @@
 CC = cc
 CFLAGS = -Wall -O2
 
-bench: main.c
-	$(CC) $(CFLAGS) -o $@ main.c
+bench: main.c ../ipc.c ../ipc.h
+	$(CC) $(CFLAGS) -I.. -o $@ main.c ../ipc.c
 
 clean:
 	rm -f bench

bench/main.c

@@ -1,3 +1,4 @@
+#define _POSIX_C_SOURCE 200809L
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -5,13 +6,7 @@
 #include <time.h>
 #include <sys/socket.h>
 #include <sys/un.h>
-
-enum {
-	Kback	= 0xf008,
-	Kret	= 0xf00d,
-	Kesc	= 0xf01b,
-	Mctrl	= 1<<2,
-};
+#include "../ipc.h"
 
 typedef struct Key Key;
 struct Key {
@@ -93,8 +88,7 @@ dial(void)
 		die("socket");
 	memset(&addr, 0, sizeof(addr));
 	addr.sun_family = AF_UNIX;
-	snprintf(addr.sun_path, sizeof(addr.sun_path),
-		"/tmp/strans.%d", getuid());
+	snprintf(addr.sun_path, sizeof(addr.sun_path), IPCPATH, getuid());
 	if(connect(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0)
 		die("connect");
 }
@@ -102,28 +96,20 @@ dial(void)
 static void
 sendkey(int key, int mod)
 {
-	unsigned char req[4];
+	unsigned char req[Ipcreqsz];
 
-	req[0] = 0;
-	req[1] = mod;
-	req[2] = key & 0xff;
-	req[3] = (key >> 8) & 0xff;
-	if(write(fd, req, 4) != 4)
+	ipcpackreq(req, 0, mod, key);
+	if(ipcsend(fd, req, sizeof req) < 0)
 		die("write");
 }
 
 static int
 readresp(void)
 {
-	unsigned char buf[256];
-	int n;
+	char buf[Ipcfieldmax+1];
+	Ipcresp resp;
 
-	if(read(fd, buf, 2) != 2)
-		return -1;
-	n = buf[1];
-	if(n > 0 && read(fd, buf + 2, n) != n)
-		return -1;
-	return 0;
+	return ipcreadresp(fd, 0, buf, sizeof buf, NULL, 0, &resp);
 }
 
 static double