85 lines
2.8 KiB
C
85 lines
2.8 KiB
C
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/*-------------------------------------------------------------------------
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*
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* ipc.h
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* POSTGRES inter-process communication definitions.
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*
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* This file is misnamed, as it no longer has much of anything directly
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* to do with IPC. The functionality here is concerned with managing
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* exit-time cleanup for either a postmaster or a backend.
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*
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*
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* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/storage/ipc.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef IPC_H
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#define IPC_H
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typedef void (*pg_on_exit_callback) (int code, Datum arg);
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typedef void (*shmem_startup_hook_type) (void);
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/*----------
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* API for handling cleanup that must occur during either ereport(ERROR)
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* or ereport(FATAL) exits from a block of code. (Typical examples are
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* undoing transient changes to shared-memory state.)
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*
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* PG_ENSURE_ERROR_CLEANUP(cleanup_function, arg);
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* {
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* ... code that might throw ereport(ERROR) or ereport(FATAL) ...
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* }
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* PG_END_ENSURE_ERROR_CLEANUP(cleanup_function, arg);
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*
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* where the cleanup code is in a function declared per pg_on_exit_callback.
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* The Datum value "arg" can carry any information the cleanup function
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* needs.
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*
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* This construct ensures that cleanup_function() will be called during
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* either ERROR or FATAL exits. It will not be called on successful
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* exit from the controlled code. (If you want it to happen then too,
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* call the function yourself from just after the construct.)
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*
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* Note: the macro arguments are multiply evaluated, so avoid side-effects.
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*----------
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*/
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#define PG_ENSURE_ERROR_CLEANUP(cleanup_function, arg) \
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do { \
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before_shmem_exit(cleanup_function, arg); \
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PG_TRY()
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#define PG_END_ENSURE_ERROR_CLEANUP(cleanup_function, arg) \
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cancel_before_shmem_exit(cleanup_function, arg); \
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PG_CATCH(); \
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{ \
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cancel_before_shmem_exit(cleanup_function, arg); \
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cleanup_function (0, arg); \
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PG_RE_THROW(); \
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} \
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PG_END_TRY(); \
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} while (0)
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/* ipc.c */
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extern PGDLLIMPORT bool proc_exit_inprogress;
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extern PGDLLIMPORT bool shmem_exit_inprogress;
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extern void proc_exit(int code) pg_attribute_noreturn();
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extern void shmem_exit(int code);
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extern void on_proc_exit(pg_on_exit_callback function, Datum arg);
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extern void on_shmem_exit(pg_on_exit_callback function, Datum arg);
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extern void before_shmem_exit(pg_on_exit_callback function, Datum arg);
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extern void cancel_before_shmem_exit(pg_on_exit_callback function, Datum arg);
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extern void on_exit_reset(void);
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extern void check_on_shmem_exit_lists_are_empty(void);
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/* ipci.c */
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extern PGDLLIMPORT shmem_startup_hook_type shmem_startup_hook;
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extern Size CalculateShmemSize(int *num_semaphores);
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extern void CreateSharedMemoryAndSemaphores(void);
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extern void InitializeShmemGUCs(void);
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#endif /* IPC_H */
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