From 470d886c32efafa1b068b5ca48afafc2198c68d4 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Tue, 20 Sep 2016 12:24:44 -0400
Subject: [PATCH] Use PostmasterRandom(), not random(), for DSM control segment
 ID.

Otherwise, every startup gets the same "random" value, which is
definitely not what was intended.
---
 src/backend/postmaster/postmaster.c | 3 +--
 src/backend/storage/ipc/dsm.c       | 3 ++-
 src/include/postmaster/postmaster.h | 1 +
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index eaf3f61ecf..67ccdce764 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -403,7 +403,6 @@ static void processCancelRequest(Port *port, void *pkt);
 static int	initMasks(fd_set *rmask);
 static void report_fork_failure_to_client(Port *port, int errnum);
 static CAC_state canAcceptConnections(void);
-static long PostmasterRandom(void);
 static void RandomSalt(char *salt, int len);
 static void signal_child(pid_t pid, int signal);
 static bool SignalSomeChildren(int signal, int targets);
@@ -5101,7 +5100,7 @@ RandomSalt(char *salt, int len)
 /*
  * PostmasterRandom
  */
-static long
+long
 PostmasterRandom(void)
 {
 	/*
diff --git a/src/backend/storage/ipc/dsm.c b/src/backend/storage/ipc/dsm.c
index d8066647a0..edafe4a3b9 100644
--- a/src/backend/storage/ipc/dsm.c
+++ b/src/backend/storage/ipc/dsm.c
@@ -36,6 +36,7 @@
 
 #include "lib/ilist.h"
 #include "miscadmin.h"
+#include "postmaster/postmaster.h"
 #include "storage/dsm.h"
 #include "storage/ipc.h"
 #include "storage/lwlock.h"
@@ -181,7 +182,7 @@ dsm_postmaster_startup(PGShmemHeader *shim)
 	{
 		Assert(dsm_control_address == NULL);
 		Assert(dsm_control_mapped_size == 0);
-		dsm_control_handle = random();
+		dsm_control_handle = (dsm_handle) PostmasterRandom();
 		if (dsm_control_handle == 0)
 			continue;
 		if (dsm_impl_op(DSM_OP_CREATE, dsm_control_handle, segsize,
diff --git a/src/include/postmaster/postmaster.h b/src/include/postmaster/postmaster.h
index b2d7776f2a..ef06d5d04c 100644
--- a/src/include/postmaster/postmaster.h
+++ b/src/include/postmaster/postmaster.h
@@ -48,6 +48,7 @@ extern const char *progname;
 
 extern void PostmasterMain(int argc, char *argv[]) pg_attribute_noreturn();
 extern void ClosePostmasterPorts(bool am_syslogger);
+extern long PostmasterRandom(void);
 
 extern int	MaxLivePostmasterChildren(void);
 
-- 
2.40.0