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Support having multiple Unix-domain sockets per postmaster.

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Replace unix_socket_directory with unix_socket_directories, which is a list
of socket directories, and adjust postmaster's code to allow zero or more
Unix-domain sockets to be created.

This is mostly a straightforward change, but since the Unix sockets ought
to be created after the TCP/IP sockets for safety reasons (better chance
of detecting a port number conflict), AddToDataDirLockFile needs to be
fixed to support out-of-order updates of data directory lockfile lines.
That's a change that had been foreseen to be necessary someday anyway.

Honza Horak, reviewed and revised by Tom Lane
This commit is contained in:
Tom Lane
2012-08-10 17:26:44 -04:00
parent 85642ec00b
commit c9b0cbe98b
17 changed files with 369 additions and 126 deletions
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92
src/backend/libpq/pqcomm.c
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@ -42,7 +42,7 @@
* StreamServerPort - Open postmaster's server port
* StreamConnection - Create new connection with client
* StreamClose - Close a client/backend connection
* TouchSocketFile - Protect socket file against /tmp cleaners
* TouchSocketFiles - Protect socket files against /tmp cleaners
* pq_init - initialize libpq at backend startup
* pq_comm_reset - reset libpq during error recovery
* pq_close - shutdown libpq at backend exit
@ -103,8 +103,8 @@ int Unix_socket_permissions;
char *Unix_socket_group;
/* Where the Unix socket file is */
static char sock_path[MAXPGPATH];
/* Where the Unix socket files are (list of palloc'd strings) */
static List *sock_paths = NIL;
/*
@ -140,8 +140,8 @@ static int internal_flush(void);
static void pq_set_nonblocking(bool nonblocking);
#ifdef HAVE_UNIX_SOCKETS
static int Lock_AF_UNIX(unsigned short portNumber, char *unixSocketName);
static int Setup_AF_UNIX(void);
static int Lock_AF_UNIX(char *unixSocketDir, char *unixSocketPath);
static int Setup_AF_UNIX(char *sock_path);
#endif /* HAVE_UNIX_SOCKETS */
@ -234,29 +234,43 @@ pq_close(int code, Datum arg)
/* StreamDoUnlink()
* Shutdown routine for backend connection
* If a Unix socket is used for communication, explicitly close it.
* If any Unix sockets are used for communication, explicitly close them.
*/
#ifdef HAVE_UNIX_SOCKETS
static void
StreamDoUnlink(int code, Datum arg)
{
Assert(sock_path[0]);
unlink(sock_path);
ListCell *l;
/* Loop through all created sockets... */
foreach(l, sock_paths)
{
char *sock_path = (char *) lfirst(l);
unlink(sock_path);
}
/* Since we're about to exit, no need to reclaim storage */
sock_paths = NIL;
}
#endif /* HAVE_UNIX_SOCKETS */
/*
* StreamServerPort -- open a "listening" port to accept connections.
*
* Successfully opened sockets are added to the ListenSocket[] array,
* at the first position that isn't PGINVALID_SOCKET.
* family should be AF_UNIX or AF_UNSPEC; portNumber is the port number.
* For AF_UNIX ports, hostName should be NULL and unixSocketDir must be
* specified. For TCP ports, hostName is either NULL for all interfaces or
* the interface to listen on, and unixSocketDir is ignored (can be NULL).
*
* Successfully opened sockets are added to the ListenSocket[] array (of
* length MaxListen), at the first position that isn't PGINVALID_SOCKET.
*
* RETURNS: STATUS_OK or STATUS_ERROR
*/
int
StreamServerPort(int family, char *hostName, unsigned short portNumber,
char *unixSocketName,
char *unixSocketDir,
pgsocket ListenSocket[], int MaxListen)
{
pgsocket fd;
@ -273,6 +287,9 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber,
int listen_index = 0;
int added = 0;
#ifdef HAVE_UNIX_SOCKETS
char unixSocketPath[MAXPGPATH];
#endif
#if !defined(WIN32) || defined(IPV6_V6ONLY)
int one = 1;
#endif
@ -286,10 +303,14 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber,
#ifdef HAVE_UNIX_SOCKETS
if (family == AF_UNIX)
{
/* Lock_AF_UNIX will also fill in sock_path. */
if (Lock_AF_UNIX(portNumber, unixSocketName) != STATUS_OK)
/*
* Create unixSocketPath from portNumber and unixSocketDir and lock
* that file path
*/
UNIXSOCK_PATH(unixSocketPath, portNumber, unixSocketDir);
if (Lock_AF_UNIX(unixSocketDir, unixSocketPath) != STATUS_OK)
return STATUS_ERROR;
service = sock_path;
service = unixSocketPath;
}
else
#endif /* HAVE_UNIX_SOCKETS */
@ -432,7 +453,7 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber,
(IS_AF_UNIX(addr->ai_family)) ?
errhint("Is another postmaster already running on port %d?"
" If not, remove socket file \"%s\" and retry.",
(int) portNumber, sock_path) :
(int) portNumber, service) :
errhint("Is another postmaster already running on port %d?"
" If not, wait a few seconds and retry.",
(int) portNumber)));
@ -443,7 +464,7 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber,
#ifdef HAVE_UNIX_SOCKETS
if (addr->ai_family == AF_UNIX)
{
if (Setup_AF_UNIX() != STATUS_OK)
if (Setup_AF_UNIX(service) != STATUS_OK)
{
closesocket(fd);
break;
@ -490,10 +511,8 @@ StreamServerPort(int family, char *hostName, unsigned short portNumber,
* Lock_AF_UNIX -- configure unix socket file path
*/
static int
Lock_AF_UNIX(unsigned short portNumber, char *unixSocketName)
Lock_AF_UNIX(char *unixSocketDir, char *unixSocketPath)
{
UNIXSOCK_PATH(sock_path, portNumber, unixSocketName);
/*
* Grab an interlock file associated with the socket file.
*
@ -502,13 +521,23 @@ Lock_AF_UNIX(unsigned short portNumber, char *unixSocketName)
* more portable, and second, it lets us remove any pre-existing socket
* file without race conditions.
*/
CreateSocketLockFile(sock_path, true);
CreateSocketLockFile(unixSocketPath, true, unixSocketDir);
/*
* Once we have the interlock, we can safely delete any pre-existing
* socket file to avoid failure at bind() time.
*/
unlink(sock_path);
unlink(unixSocketPath);
/*
* Arrange to unlink the socket file(s) at proc_exit. If this is the
* first one, set up the on_proc_exit function to do it; then add this
* socket file to the list of files to unlink.
*/
if (sock_paths == NIL)
on_proc_exit(StreamDoUnlink, 0);
sock_paths = lappend(sock_paths, pstrdup(unixSocketPath));
return STATUS_OK;
}
@ -518,11 +547,8 @@ Lock_AF_UNIX(unsigned short portNumber, char *unixSocketName)
* Setup_AF_UNIX -- configure unix socket permissions
*/
static int
Setup_AF_UNIX(void)
Setup_AF_UNIX(char *sock_path)
{
/* Arrange to unlink the socket file at exit */
on_proc_exit(StreamDoUnlink, 0);
/*
* Fix socket ownership/permission if requested. Note we must do this
* before we listen() to avoid a window where unwanted connections could
@ -704,20 +730,24 @@ StreamClose(pgsocket sock)
}
/*
* TouchSocketFile -- mark socket file as recently accessed
* TouchSocketFiles -- mark socket files as recently accessed
*
* This routine should be called every so often to ensure that the socket
* file has a recent mod date (ordinary operations on sockets usually won't
* change the mod date). That saves it from being removed by
* files have a recent mod date (ordinary operations on sockets usually won't
* change the mod date). That saves them from being removed by
* overenthusiastic /tmp-directory-cleaner daemons. (Another reason we should
* never have put the socket file in /tmp...)
*/
void
TouchSocketFile(void)
TouchSocketFiles(void)
{
/* Do nothing if we did not create a socket... */
if (sock_path[0] != '\0')
ListCell *l;
/* Loop through all created sockets... */
foreach(l, sock_paths)
{
char *sock_path = (char *) lfirst(l);
/*
* utime() is POSIX standard, utimes() is a common alternative. If we
* have neither, there's no way to affect the mod or access time of