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

ifchd/ifchd.c

@@ -1,5 +1,5 @@
 /* ifchd.c - interface change daemon
- * Time-stamp: <2010-11-12 18:40:54 njk>
+ * Time-stamp: <2010-11-13 08:07:54 njk>
  *
  * (C) 2004-2010 Nicholas J. Kain <njkain at gmail dot com>
  *
@@ -49,6 +49,7 @@
 #include "ifproto.h"
 #include "strl.h"
 #include "cap.h"
+#include "io.h"
 #include "linux.h"
 
 enum states {
@@ -126,22 +127,10 @@ static void die_nulstr(strlist_t *p)
         suicide("FATAL - NULL string in strlist");
 }
 
-static void safe_write(int fd, const char *buf, int len)
+static void writeordie(int fd, const char *buf, int len)
 {
-    ssize_t r;
+    if (safe_write(fd, buf, len) == -1)
-  retry:
+        suicide("write returned error");
-    r = write(fd, buf, len);
-    if (r != len) {
-        if (r == -1) {
-            if (errno == EINTR)
-                goto retry;
-            else
-                suicide("write returned error");
-        } else {
-            len -= r;
-            goto retry;
-        }
-    }
 }
 
 /* Writes out each element in a strlist as an argument to a keyword in
@@ -159,9 +148,9 @@ static void write_resolve_list(const char *keyword, strlist_t *list)
         buf = p->str;
         len = strlen(buf);
         if (len) {
-            safe_write(resolv_conf_fd, keyword, strlen(keyword));
+            writeordie(resolv_conf_fd, keyword, strlen(keyword));
-            safe_write(resolv_conf_fd, buf, strlen(buf));
+            writeordie(resolv_conf_fd, buf, strlen(buf));
-            safe_write(resolv_conf_fd, "\n", 1);
+            writeordie(resolv_conf_fd, "\n", 1);
         }
         p = p->next;
     }

ncmlib/CMakeLists.txt

@@ -7,6 +7,7 @@ set(NCMLIB_SRCS
   strl.c
   log.c
   cap.c
+  io.c
   )
 
 add_library(ncmlib ${NCMLIB_SRCS})

ncmlib/io.c

@@ -0,0 +1,49 @@
+/* io.c - light wrappers for POSIX i/o functions
+ * Time-stamp: <2010-11-13 08:08:39 njk>
+ *
+ * (c) 2010 Nicholas J. Kain <njkain at gmail dot com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <unistd.h>
+#include <errno.h>
+
+// returns -1 on error, >= 0 on success
+int safe_write(int fd, const char *buf, int len)
+{
+    int r;
+    int s = 0;
+    while (s < len) {
+        r = write(fd, buf + s, len - s);
+        if (r == -1) {
+            if (errno == EINTR)
+                continue;
+            else
+                return -1;
+        }
+        s += r;
+    }
+    return s;
+}

ncmlib/io.h

@@ -0,0 +1,35 @@
+/* io.h - light wrappers for POSIX i/o functions
+ * Time-stamp: <2010-11-13 08:07:43 njk>
+ *
+ * (c) 2010 Nicholas J. Kain <njkain at gmail dot com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef NCM_IO_H_
+#define NCM_IO_H_
+
+int safe_write(int fd, const char *buf, int len);
+
+#endif /* NCM_IO_H_ */

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);
+    result = safe_write(fd, (const char *)payload, sizeof(struct dhcpMessage));
-    int sent = 0;
+    if (result == -1)
-    while (1) {
+	log_error("kernel_packet: write failed: %s", strerror(errno));
-	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;
-    }
   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;
+    if (safe_write(fd, buf, count) == -1)
-    int sent = 0;
+        log_error("sockwrite: write failed: %s", strerror(errno));
-    while (1) {
+    else
-        ret = write(fd, buf + sent, count - sent);
+        log_line("sent to ifchd: %s", buf);
-        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);
 }
 
 static void deconfig_if(void)