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Commitf3868f8

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committed
A bit of code beautification/cleanup of obsolete comments. Rethink
ordering of startup operations in one or two places.
1 parent90e2663 commitf3868f8

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1 file changed

+64
-48
lines changed

1 file changed

+64
-48
lines changed

‎src/backend/postmaster/postmaster.c

Lines changed: 64 additions & 48 deletions
Original file line numberDiff line numberDiff line change
@@ -22,13 +22,22 @@
2222
* if it did much with shared memory then it would be prone to crashing
2323
* along with the backends.
2424
*
25+
* When a request message is received, we now fork() immediately.
26+
* The child process performs authentication of the request, and
27+
* then becomes a backend if successful. This allows the auth code
28+
* to be written in a simple single-threaded style (as opposed to the
29+
* crufty "poor man's multitasking" code that used to be needed).
30+
* More importantly, it ensures that blockages in non-multithreaded
31+
* libraries like SSL or PAM cannot cause denial of service to other
32+
* clients.
33+
*
2534
*
2635
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
2736
* Portions Copyright (c) 1994, Regents of the University of California
2837
*
2938
*
3039
* IDENTIFICATION
31-
* $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.224 2001/06/20 18:07:55 petere Exp $
40+
* $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.225 2001/06/21 16:43:24 tgl Exp $
3241
*
3342
* NOTES
3443
*
@@ -102,25 +111,23 @@
102111
#ifdefHAVE_SIGPROCMASK
103112
sigset_tUnBlockSig,
104113
BlockSig;
105-
106114
#else
107115
intUnBlockSig,
108116
BlockSig;
109-
110117
#endif
111118

112119
/*
113-
* Info for garbage collection. Whenever a process dies, the Postmaster
114-
* cleans up after it.Currently, NO information is required for cleanup,
115-
* but I left this structure around in case that changed.
120+
* List of active backends (or child processes anyway; we don't actually
121+
* know whether a given child has become a backend or is still in the
122+
* authorization phase). This is used mainly to keep track of how many
123+
* children we have and send them appropriate signals when necessary.
116124
*/
117125
typedefstructbkend
118126
{
119127
pid_tpid;/* process id of backend */
120128
longcancel_key;/* cancel key for cancels for this backend */
121129
}Backend;
122130

123-
/* list of active backends. For garbage collection only now. */
124131
staticDllist*BackendList;
125132

126133
/* The socket number we are listening for connections on */
@@ -155,12 +162,10 @@ static intServerSock_INET = INVALID_SOCK;/* stream socket server */
155162

156163
#ifdefHAVE_UNIX_SOCKETS
157164
staticintServerSock_UNIX=INVALID_SOCK;/* stream socket server */
158-
159165
#endif
160166

161167
#ifdefUSE_SSL
162168
staticSSL_CTX*SSL_context=NULL;/* Global SSL context */
163-
164169
#endif
165170

166171
/*
@@ -178,12 +183,14 @@ static char ExtraOptions[MAXPGPATH];
178183
staticboolReinit= true;
179184
staticintSendStop= false;
180185

186+
/* still more option variables */
181187
boolNetServer= false;/* listen on TCP/IP */
182188
boolEnableSSL= false;
183189
boolSilentMode= false;/* silent mode (-S) */
184190

185191
intCheckPointTimeout=300;
186192

193+
/* Startup/shutdown state */
187194
staticpid_tStartupPID=0,
188195
ShutdownPID=0,
189196
CheckPointPID=0;
@@ -230,7 +237,7 @@ static void ExitPostmaster(int status);
230237
staticvoidusage(constchar*);
231238
staticintServerLoop(void);
232239
staticintBackendStartup(Port*port);
233-
staticintProcessStartupPacket(Port*port);
240+
staticintProcessStartupPacket(Port*port,boolSSLdone);
234241
staticvoidprocessCancelRequest(Port*port,void*pkt);
235242
staticintinitMasks(fd_set*rmask,fd_set*wmask);
236243
staticchar*canAcceptConnections(void);
@@ -579,6 +586,20 @@ PostmasterMain(int argc, char *argv[])
579586
fprintf(stderr,"-----------------------------------------\n");
580587
}
581588

589+
/*
590+
* Initialize SSL library, if specified.
591+
*/
592+
#ifdefUSE_SSL
593+
if (EnableSSL&& !NetServer)
594+
{
595+
postmaster_error("For SSL, TCP/IP connections must be enabled.");
596+
fprintf(stderr,gettext("Try '%s --help' for more information.\n"),progname);
597+
ExitPostmaster(1);
598+
}
599+
if (EnableSSL)
600+
InitSSL();
601+
#endif
602+
582603
/*
583604
* Fork away from controlling terminal, if -S specified.
584605
*
@@ -609,17 +630,6 @@ PostmasterMain(int argc, char *argv[])
609630
/*
610631
* Establish input sockets.
611632
*/
612-
#ifdefUSE_SSL
613-
if (EnableSSL&& !NetServer)
614-
{
615-
postmaster_error("For SSL, TCP/IP connections must be enabled.");
616-
fprintf(stderr,gettext("Try '%s --help' for more information.\n"),progname);
617-
ExitPostmaster(1);
618-
}
619-
if (EnableSSL)
620-
InitSSL();
621-
#endif
622-
623633
if (NetServer)
624634
{
625635
status=StreamServerPort(AF_INET,VirtualHost,
@@ -653,8 +663,7 @@ PostmasterMain(int argc, char *argv[])
653663
reset_shared(PostPortNumber);
654664

655665
/*
656-
* Initialize the list of active backends.This list is only used for
657-
* garbage collecting the backend processes.
666+
* Initialize the list of active backends.
658667
*/
659668
BackendList=DLNewList();
660669

@@ -811,7 +820,6 @@ ServerLoop(void)
811820

812821
if (CheckPointTimeout+checkpointed>now)
813822
{
814-
815823
/*
816824
* Not time for checkpoint yet, so set a timeout for
817825
* select
@@ -883,7 +891,8 @@ ServerLoop(void)
883891
}
884892

885893
/*
886-
* new connection pending on our well-known port's socket?
894+
* New connection pending on our well-known port's socket?
895+
* If so, fork a child process to deal with it.
887896
*/
888897

889898
#ifdefHAVE_UNIX_SOCKETS
@@ -892,9 +901,15 @@ ServerLoop(void)
892901
{
893902
port=ConnCreate(ServerSock_UNIX);
894903
if (port)
904+
{
895905
BackendStartup(port);
896-
StreamClose(port->sock);
897-
ConnFree(port);
906+
/*
907+
* We no longer need the open socket or port structure
908+
* in this process
909+
*/
910+
StreamClose(port->sock);
911+
ConnFree(port);
912+
}
898913
}
899914
#endif
900915

@@ -903,9 +918,15 @@ ServerLoop(void)
903918
{
904919
port=ConnCreate(ServerSock_INET);
905920
if (port)
921+
{
906922
BackendStartup(port);
907-
StreamClose(port->sock);
908-
ConnFree(port);
923+
/*
924+
* We no longer need the open socket or port structure
925+
* in this process
926+
*/
927+
StreamClose(port->sock);
928+
ConnFree(port);
929+
}
909930
}
910931
}
911932
}
@@ -952,7 +973,7 @@ initMasks(fd_set *rmask, fd_set *wmask)
952973
* not return at all.
953974
*/
954975
staticint
955-
ProcessStartupPacket(Port*port)
976+
ProcessStartupPacket(Port*port,boolSSLdone)
956977
{
957978
StartupPacket*packet;
958979
char*rejectMsg;
@@ -983,7 +1004,7 @@ ProcessStartupPacket(Port *port)
9831004
return127;/* XXX */
9841005
}
9851006

986-
if (port->proto==NEGOTIATE_SSL_CODE)
1007+
if (port->proto==NEGOTIATE_SSL_CODE&& !SSLdone)
9871008
{
9881009
charSSLok;
9891010

@@ -1016,10 +1037,9 @@ ProcessStartupPacket(Port *port)
10161037
}
10171038
}
10181039
#endif
1019-
/* regular startup packet should follow... */
1020-
/* FIXME: by continuing to send SSL negotiation packets, a
1021-
client could run us out of stack space */
1022-
returnProcessStartupPacket(port);
1040+
/* regular startup packet, cancel, etc packet should follow... */
1041+
/* but not another SSL negotiation request */
1042+
returnProcessStartupPacket(port, true);
10231043
}
10241044

10251045
/* Could add additional special packet types here */
@@ -1211,11 +1231,8 @@ ConnFree(Port *conn)
12111231
* ClosePostmasterPorts -- close all the postmaster's open sockets
12121232
*
12131233
* This is called during child process startup to release file descriptors
1214-
* that are not needed by that child process.
1215-
*
1216-
* Note that closing the child's descriptor does not destroy the client
1217-
* connection prematurely, since the parent (postmaster) process still
1218-
* has the socket open.
1234+
* that are not needed by that child process. The postmaster still has
1235+
* them open, of course.
12191236
*/
12201237
staticvoid
12211238
ClosePostmasterPorts(void)
@@ -1685,9 +1702,7 @@ SignalChildren(int signal)
16851702
/*
16861703
* BackendStartup -- start backend process
16871704
*
1688-
* returns: STATUS_ERROR if the fork/exec failed, STATUS_OK
1689-
*otherwise.
1690-
*
1705+
* returns: STATUS_ERROR if the fork/exec failed, STATUS_OK otherwise.
16911706
*/
16921707
staticint
16931708
BackendStartup(Port*port)
@@ -1814,7 +1829,8 @@ split_opts(char **argv, int *argcp, char *s)
18141829
}
18151830

18161831
/*
1817-
* DoBackend -- set up the backend's argument list and invoke backend main().
1832+
* DoBackend -- perform authentication, and if successful, set up the
1833+
*backend's argument list and invoke backend main().
18181834
*
18191835
* This used to perform an execv() but we no longer exec the backend;
18201836
* it's the same executable as the postmaster.
@@ -1849,6 +1865,9 @@ DoBackend(Port *port)
18491865
* Signal handlers setting is moved to tcop/postgres...
18501866
*/
18511867

1868+
/* Close the postmaster's other sockets */
1869+
ClosePostmasterPorts();
1870+
18521871
SetProcessingMode(InitProcessing);
18531872

18541873
/* Save port etc. for ps status */
@@ -1859,13 +1878,10 @@ DoBackend(Port *port)
18591878

18601879
whereToSendOutput=Remote;
18611880

1862-
status=ProcessStartupPacket(port);
1881+
status=ProcessStartupPacket(port, false);
18631882
if (status==127)
18641883
return0;/* cancel request processed */
18651884

1866-
/* Close the postmaster's other sockets */
1867-
ClosePostmasterPorts();
1868-
18691885
/*
18701886
* Don't want backend to be able to see the postmaster random number
18711887
* generator state. We have to clobber the static random_seed *and*

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