Alocate rcmd{,_af}()'s *ahost argument using malloc() (well

strdup()) rather than pointing it at something that's free()d
(via freeaddrinfo(res)) before the function returns.

I appreciate that this is an API change, but it's the only way
(AFAIK) of doing this without breaking existing code that uses
rcmd{,_af}().

Pointed out by: phkmalloc

2 files changed, 14 insertions, 3 deletions

diff --git a/lib/libc/net/rcmd.3 b/lib/libc/net/rcmd.3
index 63f7fb5..7aa77e1 100644
--- a/lib/libc/net/rcmd.3
+++ b/lib/libc/net/rcmd.3
@@ -99,6 +99,10 @@ is set to the standard name of the host
 and a connection is established to a server
 residing at the well-known Internet port
 .Fa inport .
+It is up to the caller to free the memory associated with
+.Fa *ahost
+using
+.Fn free .
 .Pp
 If the connection succeeds,
 a socket in the Internet domain of type
@@ -264,6 +268,7 @@ is overloaded to mean ``All network ports in use.''
 .Xr rlogin 1 ,
 .Xr rsh 1 ,
 .Xr intro 2 ,
+.Xr free 3 ,
 .Xr rexec 3 ,
 .Xr rexecd 8 ,
 .Xr rlogind 8 ,
diff --git a/lib/libc/net/rcmd.c b/lib/libc/net/rcmd.c
index 70a18d4..6f076ed 100644
--- a/lib/libc/net/rcmd.c
+++ b/lib/libc/net/rcmd.c
@@ -100,7 +100,7 @@ rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af)
 	int s, aport, lport, timo, error;
 	char c;
 	int refused;
-	char num[8];
+	char num[8], *ohost;
 
 	pid = getpid();
 
@@ -119,8 +119,8 @@ rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af)
 				strerror(errno));
 		return (-1);
 	}
-	if (res->ai_canonname)
-		*ahost = res->ai_canonname;
+	ohost = *ahost;
+	*ahost = strdup(res->ai_canonname ? res->ai_canonname : *ahost);
 	ai = res;
 	refused = 0;
 	oldmask = sigblock(sigmask(SIGURG));
@@ -139,6 +139,8 @@ rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af)
 				    strerror(errno));
 			freeaddrinfo(res);
 			sigsetmask(oldmask);
+			free(*ahost);
+			*ahost = ohost;
 			return (-1);
 		}
 		_fcntl(s, F_SETOWN, pid);
@@ -185,6 +187,8 @@ rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af)
 		(void)fprintf(stderr, "%s: %s\n", *ahost, strerror(errno));
 		freeaddrinfo(res);
 		sigsetmask(oldmask);
+		free(*ahost);
+		*ahost = ohost;
 		return (-1);
 	}
 	lport--;
@@ -292,6 +296,8 @@ bad:
 	(void)_close(s);
 	sigsetmask(oldmask);
 	freeaddrinfo(res);
+	free(*ahost);
+	*ahost = ohost;
 	return (-1);
 }