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Attached is a patch that fixes these leaks, and does a couple other

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things as well:
  * Computes and saves a cancel key for each backend.  * fflush
  before forking, to eliminate double-buffering problems
    between postmaster and backends.

Other cleanups.

Tom Lane
This commit is contained in:
Bruce Momjian 1998-06-09 04:06:12 +00:00
parent 3912b75705
commit cb8539f9be
1 changed files with 34 additions and 8 deletions
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42
src/backend/postmaster/postmaster.c
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@ -10,7 +10,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.84 1998/06/08 22:28:26 momjian Exp $ * $Header: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v 1.85 1998/06/09 04:06:12 momjian Exp $
* *
* NOTES * NOTES
* *
@ -113,6 +113,7 @@
typedef struct bkend typedef struct bkend
{ {
int pid; /* process id of backend */ int pid; /* process id of backend */
long cancel_key; /* cancel key for cancels for this backend */
} Backend; } Backend;
/* list of active backends. For garbage collection only now. */ /* list of active backends. For garbage collection only now. */
@ -198,7 +199,14 @@ static sigset_t oldsigmask,
static int orgsigmask = sigblock(0); static int orgsigmask = sigblock(0);
#endif #endif
/*
* State for assigning random salts and cancel keys.
* Also, the global MyCancelKey passes the cancel key assigned to a given
* backend from the postmaster to that backend (via fork).
*/
static unsigned int random_seed = 0; static unsigned int random_seed = 0;
long MyCancelKey = 0;
extern char *optarg; extern char *optarg;
extern int optind, extern int optind,
@ -612,17 +620,22 @@ ServerLoop(void)
return (STATUS_ERROR); return (STATUS_ERROR);
} }
if (random_seed == 0) /*
* Select a random seed at the time of first receiving a request.
*/
while (random_seed == 0)
{ {
gettimeofday(&later, &tz); gettimeofday(&later, &tz);
/* /*
* We are not sure how much precision is in tv_usec, so we * We are not sure how much precision is in tv_usec, so we
* swap the nibbles of 'later' and XOR them with 'now' * swap the nibbles of 'later' and XOR them with 'now'.
* On the off chance that the result is 0, we loop until
* it isn't.
*/ */
random_seed = now.tv_usec ^ random_seed = now.tv_usec ^
((later.tv_usec << 16) | ((later.tv_usec << 16) |
((unsigned int)(later.tv_usec & 0xffff0000) >> 16)); ((later.tv_usec >> 16) & 0xffff));
} }
/* /*
@ -1085,6 +1098,14 @@ BackendStartup(Port *port)
} }
#endif #endif
/*
* Compute the cancel key that will be assigned to this backend.
* The backend will have its own copy in the forked-off process'
* value of MyCancelKey, so that it can transmit the key to the
* frontend.
*/
MyCancelKey = PostmasterRandom();
if (DebugLvl > 2) if (DebugLvl > 2)
{ {
char **p; char **p;
@ -1098,17 +1119,21 @@ BackendStartup(Port *port)
fprintf(stderr, "-----------------------------------------\n"); fprintf(stderr, "-----------------------------------------\n");
} }
/* Flush all stdio channels just before fork,
* to avoid double-output problems.
*/
fflush(NULL);
if ((pid = fork()) == 0) if ((pid = fork()) == 0)
{ /* child */ { /* child */
if (DoBackend(port)) if (DoBackend(port))
{ {
fprintf(stderr, "%s child[%d]: BackendStartup: backend startup failed\n", fprintf(stderr, "%s child[%d]: BackendStartup: backend startup failed\n",
progname, pid); progname, (int) getpid());
/* use _exit to keep from double-flushing stdio */ exit(1);
_exit(1);
} }
else else
_exit(0); exit(0);
} }
/* in parent */ /* in parent */
@ -1140,6 +1165,7 @@ BackendStartup(Port *port)
} }
bn->pid = pid; bn->pid = pid;
bn->cancel_key = MyCancelKey;
DLAddHead(BackendList, DLNewElem(bn)); DLAddHead(BackendList, DLNewElem(bn));
ActiveBackends = TRUE; ActiveBackends = TRUE;