Make write() and sendto() properly handle short writes and errors in ndhc.

Make ndhc write a pidfile.
Clean up defines.h and split out ifchd and ndhc specifics.

ifchd/ifchd-defines.h

@@ -1,12 +1,14 @@
-#define MAX_PATH_LENGTH 1024
+#ifndef IFCHD_DEFINES_H_
+#define IFCHD_DEFINES_H_
+
+#include "defines.h"
+
 #define PID_FILE_DEFAULT "/var/run/ifchd.pid"
 #define IFCHD_VERSION "0.8"
-
 #define COMM_SOCKET_PATH "ifchange"
 #define MAX_BUF 1024
-#define MAXLINE 1024
-
 #define SOCK_QUEUE 2
 #define CONN_TIMEOUT 60
-#define LINUX 1
+
+#endif /* IFCHD_DEFINES_H_ */
 

ifchd/ifchd.c

@@ -1,5 +1,5 @@
 /* ifchd.c - interface change daemon
- * Time-stamp: <2010-11-12 17:22:34 njk>
+ * Time-stamp: <2010-11-12 18:40:54 njk>
  *
  * (C) 2004-2010 Nicholas J. Kain <njkain at gmail dot com>
  *
@@ -39,7 +39,7 @@
 #define _GNU_SOURCE
 #include <getopt.h>
 
-#include "defines.h"
+#include "ifchd-defines.h"
 #include "malloc.h"
 #include "log.h"
 #include "chroot.h"

ifchd/linux.c

@@ -1,5 +1,5 @@
 /* linux.c - ifchd Linux-specific functions
- * Time-stamp: <2010-11-12 14:29:32 njk>
+ * Time-stamp: <2010-11-12 18:41:15 njk>
  *
  * (C) 2004-2010 Nicholas J. Kain <njkain at gmail dot com>
  *
@@ -37,7 +37,7 @@
 
 #include <errno.h>
 
-#include "defines.h"
+#include "ifchd-defines.h"
 #include "log.h"
 #include "strlist.h"
 #include "ifproto.h"

ndhc/dhcpc.c

@@ -39,6 +39,7 @@
 #include <pwd.h>
 #include <grp.h>
 
+#include "ndhc-defines.h"
 #include "dhcpd.h"
 #include "dhcpc.h"
 #include "options.h"
@@ -50,6 +51,7 @@
 #include "chroot.h"
 #include "cap.h"
 #include "strl.h"
+#include "pidfile.h"
 #include "malloc.h"
 
 #define VERSION "1.0"
@@ -456,7 +458,8 @@ static int do_work(void)
 
 int main(int argc, char **argv)
 {
-    char chroot_dir[255];
+    char pidfile[MAX_PATH_LENGTH] = "";
+    char chroot_dir[MAX_PATH_LENGTH] = PID_FILE_DEFAULT;
     int c, len;
     struct passwd *pwd;
     uid_t uid = 0;
@@ -465,6 +468,7 @@ int main(int argc, char **argv)
         {"clientid",    required_argument,  0, 'c'},
         {"foreground",  no_argument,        0, 'f'},
         {"background",  no_argument,        0, 'b'},
+        {"pidfile",     required_argument,  0, 'p'},
         {"hostname",    required_argument,  0, 'H'},
         {"hostname",    required_argument,      0, 'h'},
         {"interface",   required_argument,  0, 'i'},
@@ -481,7 +485,7 @@ int main(int argc, char **argv)
     /* get options */
     while (1) {
         int option_index = 0;
-        c = getopt_long(argc, argv, "c:fbH:h:i:np:qr:u:C:v", arg_options,
+        c = getopt_long(argc, argv, "c:fbp:H:h:i:np:qr:u:C:v", arg_options,
                         &option_index);
         if (c == -1) break;
 
@@ -502,6 +506,9 @@ int main(int argc, char **argv)
             case 'b':
                 client_config.background_if_no_lease = 1;
                 break;
+            case 'p':
+                strlcpy(pidfile, optarg, MAX_PATH_LENGTH);
+                break;
             case 'h':
             case 'H':
                 len = strlen(optarg) > 255 ? 255 : strlen(optarg);
@@ -549,6 +556,12 @@ int main(int argc, char **argv)
 
     log_line("ndhc client " VERSION " started.");
 
+    if (file_exists(pidfile, "w") == -1) {
+        log_line("FATAL - cannot open pidfile for write!");
+        exit(EXIT_FAILURE);
+    }
+    write_pid(pidfile);
+
     if (read_interface(client_config.interface, &client_config.ifindex,
                        NULL, client_config.arp) < 0)
         exit(EXIT_FAILURE);

ndhc/ndhc-defines.h

@@ -0,0 +1,11 @@
+#ifndef NDHC_DEFINES_H_
+#define NDHC_DEFINES_H_
+
+#include "defines.h"
+
+#define PID_FILE_DEFAULT "/var/run/ndhc.pid"
+#define NDHC_VERSION "1.0"
+#define MAX_BUF 1024
+
+#endif /* NDHC_DEFINES_H_ */
+

ndhc/packet.c

@@ -149,11 +149,21 @@ int raw_packet(struct dhcpMessage *payload, uint32_t source_ip,
     packet.ip.ttl = IPDEFTTL;
     packet.ip.check = checksum(&(packet.ip), sizeof(packet.ip));
 
-    result = sendto(fd, &packet, sizeof(struct udp_dhcp_packet), 0,
+    int remain = sizeof(struct udp_dhcp_packet);
+    int sent = 0;
+    while (1) {
+	result = sendto(fd, &packet + sent, remain, 0,
 			(struct sockaddr *)&dest, sizeof dest);
-    if (result <= 0) {
+	if (result == -1) {
-	log_error("write on socket failed: %s",
+	    if (errno == EINTR)
-		  strerror(errno));
+		continue;
+	    log_error("raw_packet: sendto failed: %s", strerror(errno));
+	    break;
+	}
+	remain =- result;
+	sent += result;
+	if (remain == 0)
+	    break;
     }
   out_fd:
     close(fd);
@@ -190,7 +200,21 @@ int kernel_packet(struct dhcpMessage *payload, uint32_t source_ip,
     if (connect(fd, (struct sockaddr *)&client, sizeof(struct sockaddr)) == -1)
 	goto out_fd;
 
-    result = write(fd, payload, sizeof(struct dhcpMessage));
+    int remain = sizeof(struct dhcpMessage);
+    int sent = 0;
+    while (1) {
+	result = write(fd, payload + sent, remain);
+	if (result == -1) {
+	    if (errno == EINTR)
+		continue;
+	    log_error("kernel_packet: write failed: %s", strerror(errno));
+	    break;
+	}
+	remain =- result;
+	sent += result;
+	if (remain == 0)
+	    break;
+    }
   out_fd:
     close(fd);
   out:

ndhc/script.c

@@ -144,21 +144,23 @@ static int open_ifch(void) {
     return sockfd;
 }
 
-static void sockwrite(int fd, const void *buf, size_t count)
+static void sockwrite(int fd, const char *buf, size_t count)
 {
     int ret;
-
+    int remain = count;
-  sockwrite_again:
+    int sent = 0;
-    ret = write(fd, buf, count);
+    while (1) {
+        ret = write(fd, buf + sent, remain);
         if (ret == -1) {
-        if (errno == EAGAIN)
+            if (errno == EINTR)
-            goto sockwrite_again;
+                continue;
-        log_error("error while writing to unix socket!");
+            log_error("sockwrite: write failed: %s", strerror(errno));
-        exit(EXIT_FAILURE);
+            break;
         }
-    if (ret < 0) ret = 0;
+        remain =- ret;
-    if ((unsigned int)ret < strlen(buf)) {
+        sent += ret;
-        log_error("incomplete write!");
+        if (remain == 0)
+            break;
     }
     log_line("writing: %s", (char *)buf);
 }