Factor out safe_write() into ncmlib and use it in ndhc as well.

ndhc/packet.c

@@ -10,6 +10,7 @@
 
 #include "packet.h"
 #include "log.h"
+#include "io.h"
 #include "dhcpd.h"
 #include "options.h"
 
@@ -199,20 +200,9 @@ int kernel_packet(struct dhcpMessage *payload, uint32_t source_ip,
     if (connect(fd, (struct sockaddr *)&client, sizeof(struct sockaddr)) == -1)
 	goto out_fd;
 
-    int remain = sizeof(struct dhcpMessage);
-    int sent = 0;
-    while (1) {
-	result = write(fd, ((char *)payload) + sent, remain - sent);
-	if (result == -1) {
-	    if (errno == EINTR)
-		continue;
-	    log_error("kernel_packet: write failed: %s", strerror(errno));
-	    break;
-	}
-	sent += result;
-	if (remain == sent)
-	    break;
-    }
+    result = safe_write(fd, (const char *)payload, sizeof(struct dhcpMessage));
+    if (result == -1)
+	log_error("kernel_packet: write failed: %s", strerror(errno));
   out_fd:
     close(fd);
   out:

ndhc/script.c

@@ -38,6 +38,7 @@
 #include "packet.h"
 #include "options.h"
 #include "log.h"
+#include "io.h"
 #include "script.h"
 
 static int snprintip(char *dest, size_t size, unsigned char *ip)
@@ -152,21 +153,10 @@ static int open_ifch(void) {
 
 static void sockwrite(int fd, const char *buf, size_t count)
 {
-    int ret;
-    int sent = 0;
-    while (1) {
-        ret = write(fd, buf + sent, count - sent);
-        if (ret == -1) {
-            if (errno == EINTR)
-                continue;
-            log_error("sockwrite: write failed: %s", strerror(errno));
-            break;
-        }
-        sent += ret;
-        if (sent == count)
-            break;
-    }
-    log_line("writing: %s", buf);
+    if (safe_write(fd, buf, count) == -1)
+        log_error("sockwrite: write failed: %s", strerror(errno));
+    else
+        log_line("sent to ifchd: %s", buf);
 }
 
 static void deconfig_if(void)