Sanitize buffer size

There is no point in depending on page size or supporting machines where
sizeof(char) is not one.  Also warn if ever the buffer is too small, so
people have an indication to go and increase it.  And just in case 32k
is not enough, bump the size to 1M.  Memory is cheap enough these days.

Signed-off-by: Joern Engel <joern@logfs.org>

1 files changed, 6 insertions, 2 deletions

diff --git a/cancd.c b/cancd.c
index 9e0bfe9..263ba06 100644
--- a/cancd.c
+++ b/cancd.c
@@ -421,11 +421,11 @@ static int run()
 {
 	int rc;
 	char *buf;
-	size_t bufsize = 8 * getpagesize();
+	size_t bufsize = 0x100000;
 	struct sockaddr_in from;
 	socklen_t fromlen;
 
-	buf = malloc(sizeof(char) * bufsize);
+	buf = malloc(bufsize);
 	if (!buf) {
 		syslog(LOG_ERR, "Unable to allocate memory for receive buffer: %s", strerror(errno));
 		return -ENOMEM;
@@ -443,6 +443,10 @@ static int run()
 				syslog(LOG_ERR, "Error reading from socket: %s", strerror(-rc));
 			break;
 		}
+		if (rc >= bufsize) {
+			rc = bufsize - 1;
+			syslog(LOG_ERR, "Receive buffer too small (%zd %d)", bufsize, rc);
+		}
 		buf[rc] = 0;
 		/* For now, we process one at a time */
 		do_output(buf, rc, &from, fromlen);