Implement patty_strlcpy()

Implement patty_strlcpy() for portability and correctness, to provide
BSD strlcpy() functionality for glibc systems while ensuring a nul
terminated string is written to a destination, truncating the source
string by one byte if need be to make room for the nul terminator

bin/ax25dump.c

@@ -13,6 +13,7 @@
 
 #include <patty/ax25.h>
 #include <patty/print.h>
+#include <patty/util.h>
 
 #include <patty/bin/kiss.h>
 
@@ -91,7 +92,7 @@ int main(int argc, char **argv) {
             goto error_client_socket;
         }
 
-        strncpy(ifreq.name, ifname, sizeof(ifreq.name)-1);
+        patty_strlcpy(ifreq.name, ifname, sizeof(ifreq.name));
 
         ifreq.state = PATTY_AX25_SOCK_PROMISC;
 

bin/tncd.c

@@ -14,6 +14,7 @@
 
 #include <patty/ax25.h>
 #include <patty/print.h>
+#include <patty/util.h>
 
 #include <patty/bin/kiss.h>
 
@@ -108,7 +109,7 @@ static int pty_promisc(patty_client *client,
     setsockopt_request.opt = PATTY_AX25_SOCK_IF;
     setsockopt_request.len = sizeof(ifreq);
 
-    strncpy(ifreq.name, ifname, sizeof(ifreq.name)-1);
+    patty_strlcpy(ifreq.name, ifname, sizeof(ifreq.name));
     ifreq.state = PATTY_AX25_SOCK_PROMISC;
 
     call = PATTY_CLIENT_SETSOCKOPT;
@@ -141,7 +142,7 @@ static int pty_promisc(patty_client *client,
         goto error_client_setsockopt;
     }
 
-    strncpy(pty, socket_response.path, len);
+    patty_strlcpy(pty, socket_response.path, len);
 
     return socket_response.fd;
 

include/patty/util.h

@@ -0,0 +1,8 @@
+#ifndef _PATTY_UTIL_H
+#define _PATTY_UTIL_H
+
+#include <sys/types.h>
+
+ssize_t patty_strlcpy(char *dest, const char *src, size_t n);
+
+#endif /* _PATTY_UTIL_H */

src/Makefile

@@ -9,11 +9,11 @@ LDFLAGS		+= -lutil
 
 HEADERS		= kiss.h kiss/tnc.h ax25/aprs_is.h ax25.h client.h ax25/if.h \
 		  ax25/frame.h ax25/sock.h ax25/route.h ax25/server.h daemon.h \
-		  error.h list.h hash.h dict.h timer.h print.h conf.h
+		  error.h list.h hash.h dict.h timer.h print.h util.h conf.h
 
 OBJS		= kiss.o tnc.o aprs_is.o ax25.o client.o if.o \
 		  frame.o sock.o route.o server.o daemon.o \
-		  error.o list.o hash.o dict.o timer.o print.o conf.o
+		  error.o list.o hash.o dict.o timer.o print.o util.o conf.o
 
 VERSION_MAJOR	= 0
 VERSION_MINOR	= 0.1

src/client.c

@@ -10,6 +10,7 @@
 
 #include <patty/ax25.h>
 #include <patty/daemon.h>
+#include <patty/util.h>
 
 struct _patty_client_sock {
     int fd;
@@ -49,7 +50,7 @@ patty_client *patty_client_new(const char *path) {
     memset(&addr, '\0', sizeof(addr));
     addr.sun_family = AF_UNIX;
 
-    strncpy(addr.sun_path, find_sock(path), sizeof(addr.sun_path)-1);
+    patty_strlcpy(addr.sun_path, find_sock(path), sizeof(addr.sun_path));
 
     if (connect(client->fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
         goto error_connect;
@@ -190,7 +191,7 @@ int patty_client_socket(patty_client *client,
 
     sock->fd = response.fd;
 
-    strncpy(sock->path, response.path, sizeof(sock->path));
+    patty_strlcpy(sock->path, response.path, sizeof(sock->path));
 
     if ((fd = open(sock->path, O_RDWR)) < 0) {
         goto error_open;
@@ -423,7 +424,7 @@ int patty_client_accept(patty_client *client,
     remote->fd = message.fd;
 
     memcpy(peer, &message.peer, sizeof(*peer));
-    strncpy(remote->path, message.path, sizeof(remote->path));
+    patty_strlcpy(remote->path, message.path, sizeof(remote->path));
 
     if ((pty = open(remote->path, O_RDWR)) < 0) {
         goto error_open;

src/server.c

@@ -13,6 +13,7 @@
 #include <patty/ax25.h>
 #include <patty/kiss/tnc.h>
 #include <patty/hash.h>
+#include <patty/util.h>
 
 typedef int (*patty_ax25_server_call)(patty_ax25_server *, int);
 
@@ -458,7 +459,7 @@ int patty_ax25_server_if_add(patty_ax25_server *server,
         goto error_if_fd;
     }
 
-    strncpy(entry->name, name, sizeof(entry->name)-1);
+    patty_strlcpy(entry->name, name, sizeof(entry->name));
 
     entry->iface = iface;
 
@@ -598,7 +599,7 @@ static int notify_accept(int local,
     }
 
     if (path) {
-        strncpy(message.path, path, sizeof(message.path)-1);
+        patty_strlcpy(message.path, path, sizeof(message.path));
     }
 
     return write(local, &message, sizeof(message));
@@ -1069,7 +1070,7 @@ static int listen_unix(patty_ax25_server *server, const char *path) {
 
     memset(&addr, '\0', sizeof(addr));
     addr.sun_family = AF_UNIX;
-    strncpy(addr.sun_path, path, sizeof(addr.sun_path)-1);
+    patty_strlcpy(addr.sun_path, path, sizeof(addr.sun_path));
 
     if (bind(server->fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
         goto error_bind;

src/tnc.c

@@ -14,6 +14,7 @@
 #include <patty/ax25.h>
 #include <patty/kiss.h>
 #include <patty/kiss/tnc.h>
+#include <patty/util.h>
 
 #include "config.h"
 
@@ -65,7 +66,7 @@ static int init_sock(patty_kiss_tnc *tnc, patty_kiss_tnc_info *info) {
 
     memset(&addr, '\0', sizeof(addr));
     addr.sun_family = AF_UNIX;
-    strncpy(addr.sun_path, info->device, sizeof(addr.sun_path)-1);
+    patty_strlcpy(addr.sun_path, info->device, sizeof(addr.sun_path));
 
     if (connect(tnc->fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
         goto error_connect;

src/util.c

@@ -0,0 +1,17 @@
+#include <patty/util.h>
+
+ssize_t patty_strlcpy(char *dest, const char *src, size_t n) {
+    size_t i;
+
+    for (i=0; i<n-1; i++) {
+        dest[i] = src[i];
+
+        if (src[i] == '\0') {
+            break;
+        }
+    }
+
+    dest[i] = '\0';
+
+    return i;
+}