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Macros
#define	DSM_IMPL_POSIX 1

#define	DSM_IMPL_SYSV 2

#define	DSM_IMPL_WINDOWS 3

#define	DSM_IMPL_MMAP 4

#define	USE_DSM_SYSV

#define	DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE DSM_IMPL_SYSV

#define	USE_DSM_MMAP

#define	PG_DYNSHMEM_DIR "pg_dynshmem"

#define	PG_DYNSHMEM_MMAP_FILE_PREFIX "mmap."

#define	DSM_HANDLE_INVALID ((dsm_handle) 0)

Typedefs
typedef uint32	dsm_handle

Enumerations
enum	dsm_op { DSM_OP_CREATE , DSM_OP_ATTACH , DSM_OP_DETACH , DSM_OP_DESTROY }

Functions
bool	dsm_impl_op (dsm_op op, dsm_handle handle, Size request_size, void impl_private, void mapped_address, Size *mapped_size, int elevel)

void	dsm_impl_pin_segment (dsm_handle handle, void impl_private, void *impl_private_pm_handle)

void	dsm_impl_unpin_segment (dsm_handle handle, void **impl_private)

Variables
PGDLLIMPORT int	dynamic_shared_memory_type

PGDLLIMPORT int	min_dynamic_shared_memory

Macro Definition Documentation

◆ DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE

#define DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE DSM_IMPL_SYSV

Definition at line 36 of file dsm_impl.h.

◆ DSM_HANDLE_INVALID

#define DSM_HANDLE_INVALID ((dsm_handle) 0)

Definition at line 58 of file dsm_impl.h.

◆ DSM_IMPL_MMAP

#define DSM_IMPL_MMAP 4

Definition at line 20 of file dsm_impl.h.

◆ DSM_IMPL_POSIX

#define DSM_IMPL_POSIX 1

Definition at line 17 of file dsm_impl.h.

◆ DSM_IMPL_SYSV

#define DSM_IMPL_SYSV 2

Definition at line 18 of file dsm_impl.h.

◆ DSM_IMPL_WINDOWS

#define DSM_IMPL_WINDOWS 3

Definition at line 19 of file dsm_impl.h.

◆ PG_DYNSHMEM_DIR

#define PG_DYNSHMEM_DIR "pg_dynshmem"

Definition at line 51 of file dsm_impl.h.

◆ PG_DYNSHMEM_MMAP_FILE_PREFIX

#define PG_DYNSHMEM_MMAP_FILE_PREFIX "mmap."

Definition at line 52 of file dsm_impl.h.

◆ USE_DSM_MMAP

#define USE_DSM_MMAP

Definition at line 38 of file dsm_impl.h.

◆ USE_DSM_SYSV

#define USE_DSM_SYSV

Definition at line 34 of file dsm_impl.h.

Typedef Documentation

◆ dsm_handle

typedef uint32 dsm_handle

Definition at line 55 of file dsm_impl.h.

Enumeration Type Documentation

◆ dsm_op

enum dsm_op

Enumerator
DSM_OP_CREATE
DSM_OP_ATTACH
DSM_OP_DETACH
DSM_OP_DESTROY

Definition at line 61 of file dsm_impl.h.

 {
     DSM_OP_CREATE,
     DSM_OP_ATTACH,
     DSM_OP_DETACH,
     DSM_OP_DESTROY,
 } dsm_op;

Function Documentation

◆ dsm_impl_op()

bool dsm_impl_op	(	dsm_op	op,
		dsm_handle	handle,
		Size	request_size,
		void **	impl_private,
		void **	mapped_address,
		Size *	mapped_size,
		int	elevel
	)

Definition at line 159 of file dsm_impl.c.

 {
     Assert(op == DSM_OP_CREATE || request_size == 0);
     Assert((op != DSM_OP_CREATE && op != DSM_OP_ATTACH) ||
            (*mapped_address == NULL && *mapped_size == 0));
  
     switch (dynamic_shared_memory_type)
     {
 #ifdef USE_DSM_POSIX
         case DSM_IMPL_POSIX:
             return dsm_impl_posix(op, handle, request_size, impl_private,
                                   mapped_address, mapped_size, elevel);
 #endif
 #ifdef USE_DSM_SYSV
         case DSM_IMPL_SYSV:
             return dsm_impl_sysv(op, handle, request_size, impl_private,
                                  mapped_address, mapped_size, elevel);
 #endif
 #ifdef USE_DSM_WINDOWS
         case DSM_IMPL_WINDOWS:
             return dsm_impl_windows(op, handle, request_size, impl_private,
                                     mapped_address, mapped_size, elevel);
 #endif
 #ifdef USE_DSM_MMAP
         case DSM_IMPL_MMAP:
             return dsm_impl_mmap(op, handle, request_size, impl_private,
                                  mapped_address, mapped_size, elevel);
 #endif
         default:
             elog(ERROR, "unexpected dynamic shared memory type: %d",
                  dynamic_shared_memory_type);
             return false;
     }
 }

References Assert, dsm_impl_mmap(), DSM_IMPL_MMAP, dsm_impl_posix(), DSM_IMPL_POSIX, dsm_impl_sysv(), DSM_IMPL_SYSV, DSM_IMPL_WINDOWS, DSM_OP_ATTACH, DSM_OP_CREATE, dynamic_shared_memory_type, elog, and ERROR.

Referenced by dsm_attach(), dsm_backend_startup(), dsm_cleanup_using_control_segment(), dsm_create(), dsm_detach(), dsm_detach_all(), dsm_postmaster_shutdown(), dsm_postmaster_startup(), and dsm_unpin_segment().

◆ dsm_impl_pin_segment()

void dsm_impl_pin_segment	(	dsm_handle	handle,
		void *	impl_private,
		void **	impl_private_pm_handle
	)

Definition at line 963 of file dsm_impl.c.

 {
     switch (dynamic_shared_memory_type)
     {
 #ifdef USE_DSM_WINDOWS
         case DSM_IMPL_WINDOWS:
             if (IsUnderPostmaster)
             {
                 HANDLE      hmap;
  
                 if (!DuplicateHandle(GetCurrentProcess(), impl_private,
                                      PostmasterHandle, &hmap, 0, FALSE,
                                      DUPLICATE_SAME_ACCESS))
                 {
                     char        name[64];
  
                     snprintf(name, 64, "%s.%u", SEGMENT_NAME_PREFIX, handle);
                     _dosmaperr(GetLastError());
                     ereport(ERROR,
                             (errcode_for_dynamic_shared_memory(),
                              errmsg("could not duplicate handle for \"%s\": %m",
                                     name)));
                 }
  
                 /*
                  * Here, we remember the handle that we created in the
                  * postmaster process.  This handle isn't actually usable in
                  * any process other than the postmaster, but that doesn't
                  * matter.  We're just holding onto it so that, if the segment
                  * is unpinned, dsm_impl_unpin_segment can close it.
                  */
                 *impl_private_pm_handle = hmap;
             }
             break;
 #endif
         default:
             break;
     }
 }

References _dosmaperr(), DSM_IMPL_WINDOWS, dynamic_shared_memory_type, ereport, errcode_for_dynamic_shared_memory(), errmsg(), ERROR, IsUnderPostmaster, name, SEGMENT_NAME_PREFIX, and snprintf.

Referenced by dsm_pin_segment().

◆ dsm_impl_unpin_segment()

void dsm_impl_unpin_segment	(	dsm_handle	handle,
		void **	impl_private
	)

Definition at line 1014 of file dsm_impl.c.

 {
     switch (dynamic_shared_memory_type)
     {
 #ifdef USE_DSM_WINDOWS
         case DSM_IMPL_WINDOWS:
             if (IsUnderPostmaster)
             {
                 if (*impl_private &&
                     !DuplicateHandle(PostmasterHandle, *impl_private,
                                      NULL, NULL, 0, FALSE,
                                      DUPLICATE_CLOSE_SOURCE))
                 {
                     char        name[64];
  
                     snprintf(name, 64, "%s.%u", SEGMENT_NAME_PREFIX, handle);
                     _dosmaperr(GetLastError());
                     ereport(ERROR,
                             (errcode_for_dynamic_shared_memory(),
                              errmsg("could not duplicate handle for \"%s\": %m",
                                     name)));
                 }
  
                 *impl_private = NULL;
             }
             break;
 #endif
         default:
             break;
     }
 }

References _dosmaperr(), DSM_IMPL_WINDOWS, dynamic_shared_memory_type, ereport, errcode_for_dynamic_shared_memory(), errmsg(), ERROR, IsUnderPostmaster, name, SEGMENT_NAME_PREFIX, and snprintf.

Referenced by dsm_unpin_segment().

Variable Documentation

◆ dynamic_shared_memory_type

PGDLLIMPORT int dynamic_shared_memory_type

extern

Definition at line 112 of file dsm_impl.c.

Referenced by dsm_impl_op(), dsm_impl_pin_segment(), dsm_impl_unpin_segment(), and dsm_postmaster_startup().

◆ min_dynamic_shared_memory

PGDLLIMPORT int min_dynamic_shared_memory