Copyright (C) 1994, Digital Equipment Corp. INTERFACEUshm ; FROM Ctypes IMPORT short, int, char_star, unsigned_short, void_star; FROM Utypes IMPORT time_t, key_t, size_t, swblk_t, pid_t; FROM Uipc IMPORT struct_ipc_perm; FROM Udmap IMPORT struct_dmap_star;
FROM Uproc IMPORT struct_proc_star;
** <sys/shm.h> **
** IPC Shared Memory Facility.
** Implementation Constants.
CONST (* segment low boundary address multiple *) (* (SMLBA must be a power of 2) *) (* SMLBA = ctob(CLSIZE); where does ctob come from ? - em *) (* for SYSTEM V compatibility *) (* SHMLBA = SMLBA; see SMLBA - em *)
** Permission Definitions.
SM_R = 8_0400; (* read permission *) SM_W = 8_0200; (* write permission *) (* for SYSTEM V compatibility *) SHM_R = SM_R; SHM_W = SM_W;
** ipc_perm Mode Definitions.
SM_CLEAR = 8_01000; (* clear segment on next attach *) SM_DEST = 8_02000; (* destroy seg when # attached = 0 *) (* for SYSTEM V compatibility *) SHM_INIT = SM_CLEAR; SHM_DEST = SM_DEST;
** Message Operation Flags.
SM_RDONLY = 8_010000; (* attach read-only (else read-write) *) SM_RND = 8_020000; (* round attach address to SHMLBA *) (* for SYSTEM V compatibility *) SHM_RDONLY = SM_RDONLY; SHM_RND = SM_RND;
* sizing constant (the balance are in /sys/h/param.h and /sys/conf/param.c.
SMMNI = 100; (* Max number SM segments in system *)
** Structure Definitions.
** There is a shared mem id struct for each segment in the system.
TYPE struct_smem = RECORD (* SM_PERM must be the first *) (* element in the structure. *) sm_perm: struct_ipc_perm; (* permission struct (s)*) sm_dmap: struct_dmap_star; (* disk map of shm segment (p)*) sm_ptdaddr: swblk_t; (* disk address of page table (p)*) sm_size: int; (* segment size (bytes) (p)*)The field sm_caddr is really a struct_proc_star, but this require a whole bunch of other interfaces we don't have yet. I'll make it void_star for now. EM. sm_caddr: struct_proc_star; ptr to linked proc, if loaded (s)
sm_caddr: void_star;sm_ptaddr: struct_pte_star; ptr to assoc page table (p)
sm_ptaddr: void_star; sm_rssize: size_t; (* SM resource set size (pages) (s)*) sm_lpid: pid_t; (* pid of last smop (.)*) sm_cpid: pid_t; (* pid of creator (p)*) sm_count: unsigned_short; (* reference count (x)*) sm_ccount: unsigned_short; (* number of loaded references (s)*) sm_lcount: unsigned_short; (* number of processes locking SMS (s)*) sm_flag: short; (* traced, written flags (see below)*) sm_poip: short; (* page out in progress count (s)*) sm_atime: time_t; (* last smat time (u)*) sm_dtime: time_t; (* last smdt time (u)*) sm_ctime: time_t; (* last change time (u)*) END; struct_smem_star = UNTRACED REF struct_smem; (* sys/shm.h uses a bunch of #define to provide what seems to be alternate naming: #define shmid_ds smem #define shm_perm sm_perm #define shm_segsz sm_size #define shm_cpid sm_cpid #define shm_lpid sm_lpid #define shm_nattch sm_count #define shm_atime sm_atime #define shm_dtime sm_dtime #define shm_ctime sm_ctime I guess that struct shmid_ds was the old form of that type, which when then extended in struct smem; fields that existed in struct shmid_ds were given a #define, new fields, did not get one. Because we cannot simulate the effect of #define, I suppose it is better to provide a struct_shmid_ds with "old" style names only. *) struct_shmid_ds = RECORD (* SM_PERM must be the first *) (* element in the structure. *) shm_perm: struct_ipc_perm; (* permission struct (s)*) shm_dmap: struct_dmap_star; (* disk map of shm segment (p)*) shm_ptdaddr: swblk_t; (* disk address of page table (p)*) shm_size: int; (* segment size (bytes) (p)*)
same as above
shm_caddr: struct_proc_star; ptr to linked proc, if loaded (s)
shm_caddr: void_star;
shm_ptaddr: struct_pte_star;
(* ptr to assoc page table (p)*) shm_ptaddr: void_star; shm_rssize: size_t; (* SM resource set size (pages) (s)*) shm_lpid: pid_t; (* pid of last smop (.)*) shm_cpid: pid_t; (* pid of creator (p)*) shm_count: unsigned_short; (* reference count (x)*) shm_ccount: unsigned_short; (* number of loaded references (s)*) shm_lcount: unsigned_short; (* number of processes locking SMS (s)*) shm_flag: short; (* traced, written flags (see below)*) shm_poip: short; (* page out in progress count (s)*) shm_atime: time_t; (* last smat time (u)*) shm_dtime: time_t; (* last smdt time (u)*) shm_ctime: time_t; (* last change time (u)*) END; struct_shmid_ds_star = UNTRACED REF struct_shmid_ds; CONSTNOTE: These values must align with X* flag values in text.h
SMLOCK = 8_0010; (* Being swapped in or out *) SMWANT = 8_0020; (* Wanted for swapping *) SMNOSW = 8_0100; (* Lock segment in memory *)shared memory specific commands for shmctl syscall
SHM_LOCK = 3; (* Lock segment in memory *) SHM_UNLOCK = 4; (* Unlock segment in memory *)
* sminfo structure is used by the system for bounds checking. All of
* the elements in this structure are initialized in /sys/conf/param.c.
*
* Three of the elements are configurable via the config
program
* (smmax, smmin, smbrk). If they are not config'ed, then they all
* have defaults.
TYPE struct_sminfo = RECORD smmax: int; (* max shared memory segment size *) smmin: int; (* min shared memory segment size *) smmni: int; (* # of shared memory identifiers *) smseg: int; (* max attached shared memory segs per proc *) smbrk: int; (* gap (in clicks) used between data and SM *) smsmat: int; (* max shmem attach addr (clicks) *) END; (* for SYSTEM V compatibility *) struct_shminfo = RECORD shmmax: int; (* max shared memory segment size *) shmmin: int; (* min shared memory segment size *) shmmni: int; (* # of shared memory identifiers *) shmseg: int; (* max attached shared memory segs per proc *) shmbrk: int; (* gap (in clicks) used between data and SM *) smsmat: int; (* max shmem attach addr (clicks) *) END;** shmctl(2) - shared memory control operations **
<*EXTERNAL*> PROCEDURE shmctl (shmid, cmd: int; buf: struct_shmid_ds_star): int;** shmget(2) - get shared memory segment **
<*EXTERNAL*> PROCEDURE shmget (key: key_t; size, semflg: int): int;** shmat(2), shmdt(2) - shared memory operations **
<*EXTERNAL*> PROCEDURE shmat (shmid: int; shmaddr: char_star; shmflg: int): char_star; <*EXTERNAL*> PROCEDURE shmdt (shmaddr: char_star): int; END Ushm.