sysutils/check_reload_status: Handle socket closure correctly. Fixes #14386

In adverse conditions it is possible that php-fpm can actually close a
connection from an instance of fcgi-cli and not send a respone at all. This was
not handled correctly by the recv loops, which did not recognize the return
value 0 on the blocking socket as a closed socket condition. If php-fpm closes
the socket prematurely because it is out of resources or hits some other error
condition while fcgicli is trying to read a response, this can make it loop
indefinitely.

Additionally, if read_packet returns a buffer but the header type is not
identifiable, the program goes back into another iteration of the reading loop
where again the socket may be closed and read_packet loops trying to read the
eight byte header.

To remedy the problem, the header and body loops are changed to recognize a recv
result of 0 as an error condition and drop out returning an NULL buffer
pointer. Additionally, the main program loop is changed to bail out if it
receives a packet with a header type that is not recognized.

sysutils/check_reload_status/Makefile

@@ -1,7 +1,7 @@
 # $FreeBSD$
 
 PORTNAME=	check_reload_status
-PORTVERSION=	0.0.15
+PORTVERSION=	0.0.16
 CATEGORIES?=	sysutils
 MASTER_SITES=	# empty
 DISTFILES=	# none

sysutils/check_reload_status/files/fcgicli.c

@@ -90,9 +90,9 @@ read_packet(FCGI_Header *header, int sockfd)
 
 	while (read < len) {
 		ssize_t r_read = recv(sockfd, header + read, len - read, 0);
-		if (r_read >= 0) {
+		if (r_read > 0) {
 			read += r_read;
-		} else if (errno != EINTR){
+		} else if (errno != EINTR || r_read == 0){
 			printf("Failed to read %zd header bytes: %s\n",
 			    (ssize_t)len - read, strerror(errno));
 			goto out;
@@ -119,9 +119,9 @@ read_packet(FCGI_Header *header, int sockfd)
 	read = 0;
 	while (read < len) {
 		ssize_t r_read = recv(sockfd, buf + read, len - read, 0);
-		if (r_read >= 0) {
+		if (r_read > 0) {
 			read += r_read;
-		} else if (errno != EINTR){
+		} else if (errno != EINTR || r_read == 0){
 			printf("Failed to read %zd payload bytes: %s\n",
 			    (ssize_t)len - read, strerror(errno));
 			free(buf);
@@ -358,7 +358,10 @@ main(int argc, char **argv)
 			goto endprog;
 			break;
 		default:
-			; /*nop*/
+			printf("Received unexpected header type %u, exiting",
+			    rHeader.type);
+			goto endprog;
+			break;
 		}
 	} while (rHeader.type != FCGI_END_REQUEST);