database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-12 05:01:15 +03:00
Code Activity

Get rid of not-very-portable fcntl(F_SETLK) mechanism for locking the Unix

Browse Source 
socket file, in favor of having an ordinary lockfile beside the socket file.
Clean up a few robustness problems in the lockfile code.  If postmaster is
going to reject a connection request based on database state, it will now
tell you so before authentication exchange not after.  (Of course, a failure
after is still possible if conditions change meanwhile, but this makes life
easier for a yet-to-be-written pg_ping utility.)
This commit is contained in:
Tom Lane
2000-11-29 20:59:54 +00:00
parent 1efd7330cb
commit 792b0f4666
10 changed files with 498 additions and 566 deletions
Download Patch File Download Diff File Expand all files Collapse all files

236
src/backend/postmaster/postmaster.c
View File

@@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.194 2000/11/28 23:27:55 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.195 2000/11/29 20:59:52 tgl Exp $
*
* NOTES
*
@@ -104,8 +104,6 @@ typedef struct bkend
long cancel_key; /* cancel key for cancels for this backend */
} Backend;
Port *MyBackendPort = NULL;
/* list of active backends. For garbage collection only now. */
static Dllist *BackendList;
@@ -114,8 +112,8 @@ static Dllist *PortList;
/* The socket number we are listening for connections on */
int PostPortNumber;
char * UnixSocketDir;
char * Virtual_host;
char *UnixSocketDir;
char *VirtualHost;
/*
* MaxBackends is the actual limit on the number of backends we will
@@ -216,6 +214,7 @@ static int BackendStartup(Port *port);
static int readStartupPacket(void *arg, PacketLen len, void *pkt);
static int processCancelRequest(Port *port, PacketLen len, void *pkt);
static int initMasks(fd_set *rmask, fd_set *wmask);
static char *canAcceptConnections(void);
static long PostmasterRandom(void);
static void RandomSalt(char *salt);
static void SignalChildren(SIGNAL_ARGS);
@@ -252,7 +251,7 @@ checkDataDir(const char *checkdir)
"database system either by specifying the -D invocation "
"option or by setting the PGDATA environment variable.\n\n",
progname);
exit(2);
ExitPostmaster(2);
}
snprintf(path, sizeof(path), "%s%cglobal%cpg_control",
@@ -265,7 +264,7 @@ checkDataDir(const char *checkdir)
"\n\tExpected to find it in the PGDATA directory \"%s\","
"\n\tbut unable to open file \"%s\": %s\n\n",
progname, checkdir, path, strerror(errno));
exit(2);
ExitPostmaster(2);
}
FreeFile(fp);
@@ -299,12 +298,12 @@ PostmasterMain(int argc, char *argv[])
if (strcmp(argv[1], "--help")==0 || strcmp(argv[1], "-?")==0)
{
usage(progname);
exit(0);
ExitPostmaster(0);
}
if (strcmp(argv[1], "--version")==0 || strcmp(argv[1], "-V")==0)
{
puts("postmaster (PostgreSQL) " PG_VERSION);
exit(0);
ExitPostmaster(0);
}
}
@@ -367,7 +366,7 @@ PostmasterMain(int argc, char *argv[])
case '?':
fprintf(stderr, "Try '%s --help' for more information.\n", progname);
exit(1);
ExitPostmaster(1);
}
}
@@ -378,7 +377,7 @@ PostmasterMain(int argc, char *argv[])
{
fprintf(stderr, "%s: invalid argument -- %s\n", progname, argv[optind]);
fprintf(stderr, "Try '%s --help' for more information.\n", progname);
exit(1);
ExitPostmaster(1);
}
checkDataDir(potential_DataDir); /* issues error messages */
@@ -427,7 +426,7 @@ PostmasterMain(int argc, char *argv[])
enableFsync = false;
break;
case 'h':
Virtual_host = optarg;
VirtualHost = optarg;
break;
case 'i':
NetServer = true;
@@ -525,7 +524,7 @@ PostmasterMain(int argc, char *argv[])
default:
/* shouldn't get here */
fprintf(stderr, "Try '%s --help' for more information.\n", progname);
exit(1);
ExitPostmaster(1);
}
}
@@ -542,7 +541,7 @@ PostmasterMain(int argc, char *argv[])
*/
fprintf(stderr, "%s: The number of buffers (-B) must be at least twice the number of allowed connections (-N) and at least 16.\n",
progname);
exit(1);
ExitPostmaster(1);
}
if (DebugLvl > 2)
@@ -558,6 +557,27 @@ PostmasterMain(int argc, char *argv[])
fprintf(stderr, "-----------------------------------------\n");
}
/*
* Fork away from controlling terminal, if -S specified.
*
* Must do this before we grab any interlock files, else the interlocks
* will show the wrong PID.
*/
if (SilentMode)
pmdaemonize(argc, argv);
/*
* Create lockfile for data directory.
*
* We want to do this before we try to grab the input sockets, because
* the data directory interlock is more reliable than the socket-file
* interlock (thanks to whoever decided to put socket files in /tmp :-().
* For the same reason, it's best to grab the TCP socket before the
* Unix socket.
*/
if (! CreateDataDirLockFile(DataDir, true))
ExitPostmaster(1);
/*
* Establish input sockets.
*/
@@ -566,7 +586,7 @@ PostmasterMain(int argc, char *argv[])
{
fprintf(stderr, "%s: For SSL, TCP/IP connections must be enabled. See -? for help.\n",
progname);
exit(1);
ExitPostmaster(1);
}
if (EnableSSL)
InitSSL();
@@ -574,7 +594,7 @@ PostmasterMain(int argc, char *argv[])
if (NetServer)
{
status = StreamServerPort(AF_INET, Virtual_host,
status = StreamServerPort(AF_INET, VirtualHost,
(unsigned short) PostPortNumber, UnixSocketDir,
&ServerSock_INET);
if (status != STATUS_OK)
@@ -586,7 +606,7 @@ PostmasterMain(int argc, char *argv[])
}
#ifdef HAVE_UNIX_SOCKETS
status = StreamServerPort(AF_UNIX, Virtual_host,
status = StreamServerPort(AF_UNIX, VirtualHost,
(unsigned short) PostPortNumber, UnixSocketDir,
&ServerSock_UNIX);
if (status != STATUS_OK)
@@ -599,7 +619,9 @@ PostmasterMain(int argc, char *argv[])
XLOGPathInit();
/* set up shared memory and semaphores */
/*
* Set up shared memory and semaphores.
*/
reset_shared(PostPortNumber);
/*
@@ -609,35 +631,12 @@ PostmasterMain(int argc, char *argv[])
BackendList = DLNewList();
PortList = DLNewList();
if (SilentMode)
pmdaemonize(argc, argv);
else
{
/*
* create pid file. if the file has already existed, exits.
*/
SetPidFname(DataDir);
if (SetPidFile(getpid()) == 0)
{
if (!CreateOptsFile(argc, argv))
{
UnlinkPidFile();
ExitPostmaster(1);
return 0; /* not reached */
}
}
else
{
ExitPostmaster(1);
return 0; /* not reached */
}
/*
* register clean up proc
*/
on_proc_exit(UnlinkPidFile, 0);
}
/*
* Record postmaster options. We delay this till now to avoid recording
* bogus options (eg, NBuffers too high for available memory).
*/
if (!CreateOptsFile(argc, argv))
ExitPostmaster(1);
/*
* Set up signal handlers for the postmaster process.
@@ -658,11 +657,18 @@ PostmasterMain(int argc, char *argv[])
pqsignal(SIGTTOU, SIG_IGN); /* ignored */
pqsignal(SIGWINCH, dumpstatus); /* dump port status */
/*
* We're ready to rock and roll...
*/
StartupPID = StartupDataBase();
status = ServerLoop();
/*
* ServerLoop probably shouldn't ever return, but if it does, close down.
*/
ExitPostmaster(status != STATUS_OK);
return 0; /* not reached */
}
@@ -672,8 +678,6 @@ pmdaemonize(int argc, char *argv[])
int i;
pid_t pid;
SetPidFname(DataDir);
pid = fork();
if (pid == -1)
{
@@ -683,36 +687,8 @@ pmdaemonize(int argc, char *argv[])
}
else if (pid)
{ /* parent */
/*
* create pid file. if the file has already existed, exits.
*/
if (SetPidFile(pid) == 0)
{
if (!CreateOptsFile(argc, argv))
{
/*
* Failed to create opts file. kill the child and exit
* now.
*/
UnlinkPidFile();
kill(pid, SIGTERM);
ExitPostmaster(1);
return; /* not reached */
}
_exit(0);
}
else
{
/*
* Failed to create pid file. kill the child and exit now.
*/
kill(pid, SIGTERM);
ExitPostmaster(1);
return; /* not reached */
}
/* Parent should just exit, without doing any atexit cleanup */
_exit(0);
}
/* GH: If there's no setsid(), we hopefully don't need silent mode.
@@ -723,7 +699,7 @@ pmdaemonize(int argc, char *argv[])
{
fprintf(stderr, "%s: ", progname);
perror("cannot disassociate from controlling TTY");
exit(1);
ExitPostmaster(1);
}
#endif
i = open(NULL_DEV, O_RDWR | PG_BINARY);
@@ -731,11 +707,6 @@ pmdaemonize(int argc, char *argv[])
dup2(i, 1);
dup2(i, 2);
close(i);
/*
* register clean up proc
*/
on_proc_exit(UnlinkPidFile, 0);
}
@@ -960,24 +931,19 @@ ServerLoop(void)
if (status == STATUS_OK && port->pktInfo.state == Idle)
{
/*
* Can't start backend if max backend count is exceeded.
* Can we accept a connection now?
*
* The same when data base is in startup/shutdown mode.
* Even though readStartupPacket() already checked,
* we have to check again in case conditions changed
* while negotiating authentication.
*/
if (Shutdown > NoShutdown)
PacketSendError(&port->pktInfo,
"The Data Base System is shutting down");
else if (StartupPID)
PacketSendError(&port->pktInfo,
"The Data Base System is starting up");
else if (FatalError)
PacketSendError(&port->pktInfo,
"The Data Base System is in recovery mode");
else if (CountChildren() >= MaxBackends)
PacketSendError(&port->pktInfo,
"Sorry, too many clients already");
char *rejectMsg = canAcceptConnections();
if (rejectMsg != NULL)
{
PacketSendError(&port->pktInfo, rejectMsg);
}
else
{
@@ -1066,6 +1032,7 @@ readStartupPacket(void *arg, PacketLen len, void *pkt)
{
Port *port;
StartupPacket *si;
char *rejectMsg;
port = (Port *) arg;
si = (StartupPacket *) pkt;
@@ -1158,6 +1125,19 @@ readStartupPacket(void *arg, PacketLen len, void *pkt)
return STATUS_OK; /* don't close the connection yet */
}
/*
* If we're going to reject the connection due to database state,
* say so now instead of wasting cycles on an authentication exchange.
* (This also allows a pg_ping utility to be written.)
*/
rejectMsg = canAcceptConnections();
if (rejectMsg != NULL)
{
PacketSendError(&port->pktInfo, rejectMsg);
return STATUS_OK; /* don't close the connection yet */
}
/* Start the authentication itself. */
be_recvauth(port);
@@ -1226,6 +1206,28 @@ processCancelRequest(Port *port, PacketLen len, void *pkt)
return STATUS_ERROR;
}
/*
* canAcceptConnections --- check to see if database state allows connections.
*
* If we are open for business, return NULL, otherwise return an error message
* string suitable for rejecting a connection request.
*/
static char *
canAcceptConnections(void)
{
/* Can't start backends when in startup/shutdown/recovery state. */
if (Shutdown > NoShutdown)
return "The Data Base System is shutting down";
if (StartupPID)
return "The Data Base System is starting up";
if (FatalError)
return "The Data Base System is in recovery mode";
/* Can't start backend if max backend count is exceeded. */
if (CountChildren() >= MaxBackends)
return "Sorry, too many clients already";
return NULL;
}
/*
* ConnCreate -- create a local connection data structure
@@ -1423,7 +1425,7 @@ pmdie(SIGNAL_ARGS)
}
/* exit postmaster */
proc_exit(0);
ExitPostmaster(0);
}
/*
@@ -1465,9 +1467,9 @@ reaper(SIGNAL_ARGS)
{
fprintf(stderr, "Shutdown failed - abort\n");
fflush(stderr);
proc_exit(1);
ExitPostmaster(1);
}
proc_exit(0);
ExitPostmaster(0);
}
if (StartupPID > 0)
{
@@ -1477,7 +1479,7 @@ reaper(SIGNAL_ARGS)
{
fprintf(stderr, "Startup failed - abort\n");
fflush(stderr);
proc_exit(1);
ExitPostmaster(1);
}
StartupPID = 0;
FatalError = false;
@@ -1507,7 +1509,7 @@ reaper(SIGNAL_ARGS)
{
/*
* Wait for all children exit then StartupDataBase.
* Wait for all children exit, then reset shmem and StartupDataBase.
*/
if (DLGetHead(BackendList))
return;
@@ -1518,8 +1520,10 @@ reaper(SIGNAL_ARGS)
"Reinitializing shared memory and semaphores\n",
ctime(&tnow));
fflush(stderr);
shmem_exit(0);
reset_shared(PostPortNumber);
StartupPID = StartupDataBase();
return;
}
@@ -1744,10 +1748,10 @@ BackendStartup(Port *port)
{
fprintf(stderr, "%s child[%d]: BackendStartup: backend startup failed\n",
progname, (int) getpid());
exit(1);
ExitPostmaster(1);
}
else
exit(0);
ExitPostmaster(0);
}
/* in parent */
@@ -1943,9 +1947,9 @@ DoBackend(Port *port)
/*
* Release postmaster's working memory context so that backend can
* recycle the space. Note we couldn't do it earlier than here,
* because port pointer is pointing into that space! But now we
* have copied all the interesting info into safe local storage.
* recycle the space. Note this does not trash *MyProcPort, because
* ConnCreate() allocated that space with malloc() ... else we'd need
* to copy the Port data here.
*/
MemoryContextSwitchTo(TopMemoryContext);
MemoryContextDelete(PostmasterContext);
@@ -1968,6 +1972,8 @@ DoBackend(Port *port)
/*
* ExitPostmaster -- cleanup
*
* Do NOT call exit() directly --- always go through here!
*/
static void
ExitPostmaster(int status)
@@ -2099,24 +2105,24 @@ InitSSL(void)
if (!SSL_context)
{
fprintf(stderr, "Failed to create SSL context: %s\n", ERR_reason_error_string(ERR_get_error()));
exit(1);
ExitPostmaster(1);
}
snprintf(fnbuf, sizeof(fnbuf), "%s/server.crt", DataDir);
if (!SSL_CTX_use_certificate_file(SSL_context, fnbuf, SSL_FILETYPE_PEM))
{
fprintf(stderr, "Failed to load server certificate (%s): %s\n", fnbuf, ERR_reason_error_string(ERR_get_error()));
exit(1);
ExitPostmaster(1);
}
snprintf(fnbuf, sizeof(fnbuf), "%s/server.key", DataDir);
if (!SSL_CTX_use_PrivateKey_file(SSL_context, fnbuf, SSL_FILETYPE_PEM))
{
fprintf(stderr, "Failed to load private key file (%s): %s\n", fnbuf, ERR_reason_error_string(ERR_get_error()));
exit(1);
ExitPostmaster(1);
}
if (!SSL_CTX_check_private_key(SSL_context))
{
fprintf(stderr, "Check of private key failed: %s\n", ERR_reason_error_string(ERR_get_error()));
exit(1);
ExitPostmaster(1);
}
}
@@ -2178,7 +2184,7 @@ SSDataBase(int xlop)
PG_SETMASK(&BlockSig);
BootstrapMain(ac, av);
exit(0);
ExitPostmaster(0);
}
/* in parent */