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Diffstat (limited to '')
-rw-r--r-- | src/include/storage/pmsignal.h | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h new file mode 100644 index 0000000..56c5ec4 --- /dev/null +++ b/src/include/storage/pmsignal.h @@ -0,0 +1,94 @@ +/*------------------------------------------------------------------------- + * + * pmsignal.h + * routines for signaling the postmaster from its child processes + * + * + * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/include/storage/pmsignal.h + * + *------------------------------------------------------------------------- + */ +#ifndef PMSIGNAL_H +#define PMSIGNAL_H + +#include <signal.h> + +#ifdef HAVE_SYS_PRCTL_H +#include "sys/prctl.h" +#endif + +#ifdef HAVE_SYS_PROCCTL_H +#include "sys/procctl.h" +#endif + +/* + * Reasons for signaling the postmaster. We can cope with simultaneous + * signals for different reasons. If the same reason is signaled multiple + * times in quick succession, however, the postmaster is likely to observe + * only one notification of it. This is okay for the present uses. + */ +typedef enum +{ + PMSIGNAL_RECOVERY_STARTED, /* recovery has started */ + PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */ + PMSIGNAL_WAKEN_ARCHIVER, /* send a NOTIFY signal to xlog archiver */ + PMSIGNAL_ROTATE_LOGFILE, /* send SIGUSR1 to syslogger to rotate logfile */ + PMSIGNAL_START_AUTOVAC_LAUNCHER, /* start an autovacuum launcher */ + PMSIGNAL_START_AUTOVAC_WORKER, /* start an autovacuum worker */ + PMSIGNAL_BACKGROUND_WORKER_CHANGE, /* background worker state change */ + PMSIGNAL_START_WALRECEIVER, /* start a walreceiver */ + PMSIGNAL_ADVANCE_STATE_MACHINE, /* advance postmaster's state machine */ + + NUM_PMSIGNALS /* Must be last value of enum! */ +} PMSignalReason; + +/* PMSignalData is an opaque struct, details known only within pmsignal.c */ +typedef struct PMSignalData PMSignalData; + +/* + * prototypes for functions in pmsignal.c + */ +extern Size PMSignalShmemSize(void); +extern void PMSignalShmemInit(void); +extern void SendPostmasterSignal(PMSignalReason reason); +extern bool CheckPostmasterSignal(PMSignalReason reason); +extern int AssignPostmasterChildSlot(void); +extern bool ReleasePostmasterChildSlot(int slot); +extern bool IsPostmasterChildWalSender(int slot); +extern void MarkPostmasterChildActive(void); +extern void MarkPostmasterChildInactive(void); +extern void MarkPostmasterChildWalSender(void); +extern bool PostmasterIsAliveInternal(void); +extern void PostmasterDeathSignalInit(void); + + +/* + * Do we have a way to ask for a signal on parent death? + * + * If we do, pmsignal.c will set up a signal handler, that sets a flag when + * the parent dies. Checking the flag first makes PostmasterIsAlive() a lot + * cheaper in usual case that the postmaster is alive. + */ +#if (defined(HAVE_SYS_PRCTL_H) && defined(PR_SET_PDEATHSIG)) || \ + (defined(HAVE_SYS_PROCCTL_H) && defined(PROC_PDEATHSIG_CTL)) +#define USE_POSTMASTER_DEATH_SIGNAL +#endif + +#ifdef USE_POSTMASTER_DEATH_SIGNAL +extern volatile sig_atomic_t postmaster_possibly_dead; + +static inline bool +PostmasterIsAlive(void) +{ + if (likely(!postmaster_possibly_dead)) + return true; + return PostmasterIsAliveInternal(); +} +#else +#define PostmasterIsAlive() PostmasterIsAliveInternal() +#endif + +#endif /* PMSIGNAL_H */ |