- Added three new interfaces, NgAllocRecvMsg(), NgAllocRecvAsciiMsg(),

  and NgAllocRecvData(), that dynamically allocate buffer for a binary
  message, an ascii message, and a data packet, respectively.  The size
  of the allocated buffer is equal to the socket's receive buffer size
  to guarantee that a message or a data packet is not truncated.

- Get rid of the static size buffer in NgSendAsciiMsg().

OK'ed by:	archie, julian

5 files changed, 109 insertions, 9 deletions

diff --git a/lib/libnetgraph/Makefile b/lib/libnetgraph/Makefile
index 227da19..ff8a3be 100644
--- a/lib/libnetgraph/Makefile
+++ b/lib/libnetgraph/Makefile
@@ -16,9 +16,12 @@ MLINKS+=	netgraph.3 NgSendMsg.3
 MLINKS+=	netgraph.3 NgSendAsciiMsg.3
 MLINKS+=	netgraph.3 NgSendMsgReply.3
 MLINKS+=	netgraph.3 NgRecvMsg.3
+MLINKS+=	netgraph.3 NgAllocRecvMsg.3
 MLINKS+=	netgraph.3 NgRecvAsciiMsg.3
+MLINKS+=	netgraph.3 NgAllocRecvAsciiMsg.3
 MLINKS+=	netgraph.3 NgSendData.3
 MLINKS+=	netgraph.3 NgRecvData.3
+MLINKS+=	netgraph.3 NgAllocRecvData.3
 MLINKS+=	netgraph.3 NgSetDebug.3
 MLINKS+=	netgraph.3 NgSetErrLog.3
 
diff --git a/lib/libnetgraph/msg.c b/lib/libnetgraph/msg.c
index f89c27f..90b6278 100644
--- a/lib/libnetgraph/msg.c
+++ b/lib/libnetgraph/msg.c
@@ -91,13 +91,10 @@ NgSendMsg(int cs, const char *path,
 int
 NgSendAsciiMsg(int cs, const char *path, const char *fmt, ...)
 {
-	const int bufSize = 1024;
-	char replybuf[2 * sizeof(struct ng_mesg) + bufSize];
-	struct ng_mesg *const reply = (struct ng_mesg *)replybuf;
-	struct ng_mesg *const binary = (struct ng_mesg *)reply->data;
-	struct ng_mesg *ascii;
+	struct ng_mesg *reply, *binary, *ascii;
 	char *buf, *cmd, *args;
 	va_list fmtargs;
+	int token;
 
 	/* Parse out command and arguments */
 	va_start(fmtargs, fmt);
@@ -139,17 +136,22 @@ NgSendAsciiMsg(int cs, const char *path, const char *fmt, ...)
 	free(ascii);
 
 	/* Get reply */
-	if (NgRecvMsg(cs, reply, sizeof(replybuf), NULL) < 0)
+	if (NgAllocRecvMsg(cs, &reply, NULL) < 0)
 		return (-1);
 
 	/* Now send binary version */
+	binary = (struct ng_mesg *)reply->data;
 	if (++gMsgId < 0)
 		gMsgId = 1;
 	binary->header.token = gMsgId;
 	if (NgDeliverMsg(cs,
-	    path, binary, binary->data, binary->header.arglen) < 0)
+	    path, binary, binary->data, binary->header.arglen) < 0) {
+		free(reply);
 		return (-1);
-	return (binary->header.token);
+	}
+	token = binary->header.token;
+	free(reply);
+	return (token);
 }
 
 /*
@@ -277,6 +279,24 @@ errout:
 }
 
 /*
+ * Identical to NgRecvMsg() except buffer is dynamically allocated.
+ */
+int
+NgAllocRecvMsg(int cs, struct ng_mesg **rep, char *path)
+{
+	int len;
+	socklen_t optlen;
+
+	optlen = sizeof(len);
+	if (getsockopt(cs, SOL_SOCKET, SO_RCVBUF, &len, &optlen) == -1 ||
+	    (*rep = malloc(len)) == NULL)
+		return (-1);
+	if ((len = NgRecvMsg(cs, *rep, len, path)) < 0)
+		free(*rep);
+	return (len);
+}
+
+/*
  * Receive a control message and convert the arguments to ASCII
  */
 int
@@ -321,3 +341,20 @@ fail:
 	return (0);
 }
 
+/*
+ * Identical to NgRecvAsciiMsg() except buffer is dynamically allocated.
+ */
+int
+NgAllocRecvAsciiMsg(int cs, struct ng_mesg **reply, char *path)
+{
+	int len;
+	socklen_t optlen;
+
+	optlen = sizeof(len);
+	if (getsockopt(cs, SOL_SOCKET, SO_RCVBUF, &len, &optlen) == -1 ||
+	    (*reply = malloc(len)) == NULL)
+		return (-1);
+	if ((len = NgRecvAsciiMsg(cs, *reply, len, path)) < 0)
+		free(*reply);
+	return (len);
+}
diff --git a/lib/libnetgraph/netgraph.3 b/lib/libnetgraph/netgraph.3
index 8520170..108775e 100644
--- a/lib/libnetgraph/netgraph.3
+++ b/lib/libnetgraph/netgraph.3
@@ -35,16 +35,22 @@
 .\" $FreeBSD$
 .\" $Whistle: netgraph.3,v 1.7 1999/01/25 07:14:06 archie Exp $
 .\"
-.Dd January 19, 1999
+.Dd January 27, 2004
 .Dt NETGRAPH 3
 .Os
 .Sh NAME
 .Nm NgMkSockNode ,
 .Nm NgNameNode ,
 .Nm NgSendMsg ,
+.Nm NgSendAsciiMsg ,
+.Nm NgSendMsgReply ,
 .Nm NgRecvMsg ,
+.Nm NgAllocRecvMsg ,
+.Nm NgRecvAsciiMsg ,
+.Nm NgAllocRecvAsciiMsg ,
 .Nm NgSendData ,
 .Nm NgRecvData ,
+.Nm NgAllocRecvData ,
 .Nm NgSetDebug ,
 .Nm NgSetErrLog
 .Nd netgraph user library
@@ -71,12 +77,18 @@
 .Ft int
 .Fn NgRecvMsg "int cs" "struct ng_mesg *rep" "size_t replen" "char *path"
 .Ft int
+.Fn NgAllocRecvMsg "int cs" "struct ng_mesg **rep" "char *path"
+.Ft int
 .Fn NgRecvAsciiMsg "int cs" "struct ng_mesg *rep" "size_t replen" "char *path"
 .Ft int
+.Fn NgAllocRecvAsciiMsg "int cs" "struct ng_mesg **rep" "char *path"
+.Ft int
 .Fn NgSendData "int ds" "const char *hook" "const u_char *buf" "size_t len"
 .Ft int
 .Fn NgRecvData "int ds" "u_char *buf" "size_t len" "char *hook"
 .Ft int
+.Fn NgAllocRecvData "int ds" "u_char **buf" "char *hook"
+.Ft int
 .Fn NgSetDebug "int level"
 .Ft void
 .Fo NgSetErrLog
@@ -204,6 +216,15 @@ The length of the control message is returned.
 A return value of zero indicates that the socket was closed.
 .Pp
 The
+.Fn NgAllocRecvMsg
+function works exactly like
+.Fn NgRecvMsg ,
+except that the buffer for a message is dynamically allocated
+to guarantee that a message is not truncated.
+The size of the buffer is equal to the socket's receive buffer size.
+The caller is responsible for freeing the buffer when it is no longer required.
+.Pp
+The
 .Fn NgRecvAsciiMsg
 function works exactly like
 .Fn NgRecvMsg ,
@@ -222,6 +243,15 @@ version of the arguments (and the reply
 header argument length field will be adjusted).
 .Pp
 The
+.Fn NgAllocRecvAsciiMsg
+function works exactly like
+.Fn NgRecvAsciiMsg ,
+except that the buffer for a message is dynamically allocated
+to guarantee that a message is not truncated.
+The size of the buffer is equal to the socket's receive buffer size.
+The caller is responsible for freeing the buffer when it is no longer required.
+.Pp
+The
 .Fn NgSendData
 function writes a data packet out on the specified hook of the node
 corresponding to data socket
@@ -252,6 +282,15 @@ The length of the packet is returned.
 A return value of zero indicates that the socket was closed.
 .Pp
 The
+.Fn NgAllocRecvData
+function works exactly like
+.Fn NgRecvData ,
+except that the buffer for a data packet is dynamically allocated
+to guarantee that a data packet is not truncated.
+The size of the buffer is equal to the socket's receive buffer size.
+The caller is responsible for freeing the buffer when it is no longer required.
+.Pp
+The
 .Fn NgSetDebug
 and
 .Fn NgSetErrLog
diff --git a/lib/libnetgraph/netgraph.h b/lib/libnetgraph/netgraph.h
index d0f402c..4eb15bd 100644
--- a/lib/libnetgraph/netgraph.h
+++ b/lib/libnetgraph/netgraph.h
@@ -54,9 +54,12 @@ int	NgSendAsciiMsg(int, const char *, const char *, ...) __printflike(3, 4);
 int	NgSendReplyMsg(int, const char *,
 		const struct ng_mesg *, const void *, size_t);
 int	NgRecvMsg(int, struct ng_mesg *, size_t, char *);
+int	NgAllocRecvMsg(int, struct ng_mesg **, char *);
 int	NgRecvAsciiMsg(int, struct ng_mesg *, size_t, char *);
+int	NgAllocRecvAsciiMsg(int, struct ng_mesg **, char *);
 int	NgSendData(int, const char *, const u_char *, size_t);
 int	NgRecvData(int, u_char *, size_t, char *);
+int	NgAllocRecvData(int, u_char **, char *);
 int	NgSetDebug(int);
 void	NgSetErrLog(void (*)(const char *fmt, ...),
 	    void (*)(const char *fmt, ...));
diff --git a/lib/libnetgraph/sock.c b/lib/libnetgraph/sock.c
index 7485baa..070abea 100644
--- a/lib/libnetgraph/sock.c
+++ b/lib/libnetgraph/sock.c
@@ -243,6 +243,24 @@ NgRecvData(int ds, u_char * buf, size_t len, char *hook)
 }
 
 /*
+ * Identical to NgRecvData() except buffer is dynamically allocated.
+ */
+int
+NgAllocRecvData(int ds, u_char **buf, char *hook)
+{
+	int len;
+	socklen_t optlen;
+
+	optlen = sizeof(len);
+	if (getsockopt(ds, SOL_SOCKET, SO_RCVBUF, &len, &optlen) == -1 ||
+	    (*buf = malloc(len)) == NULL)
+		return (-1);
+	if ((len = NgRecvData(ds, *buf, len, hook)) < 0)
+		free(*buf);
+	return (len);
+}
+
+/*
  * Write a packet to a data socket. The packet will be sent
  * out the corresponding node on the specified hook.
  * Returns -1 if error and sets errno.