Enrico Fraccaroli (Galfurian)
164 lines
5.7 KiB
C
164 lines
5.7 KiB
C
/// @file shm.h
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/// @brief Definition of structure for managing shared memories.
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/// @copyright (c) 2014-2023 This file is distributed under the MIT License.
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/// See LICENSE.md for details.
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#pragma once
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#include "sys/types.h"
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#include "stddef.h"
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#include "sys/ipc.h"
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#include "time.h"
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/// Data type for storing the number of attaches.
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typedef unsigned long shmatt_t;
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/// @brief Shared memory data structure.
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struct shmid_ds {
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/// Operation permission struct.
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struct ipc_perm shm_perm;
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/// Size of segment in bytes.
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size_t shm_segsz;
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/// Time of last attach.
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time_t shm_atime;
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/// Time of last detach.
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time_t shm_dtime;
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/// Time of last change.
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time_t shm_ctime;
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/// Pid of creator.
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pid_t shm_cpid;
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/// Pid of last operator.
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pid_t shm_lpid;
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/// Number of current attaches.
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shmatt_t shm_nattch;
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};
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#if 0
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#include "debug.h"
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#include "time.h"
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#include "kheap.h"
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#include "stddef.h"
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#include "paging.h"
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#include "syscall.h"
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#include "scheduler.h"
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//======== Permission flag for shmget ==========================================
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// or S_IRUGO from <linux/stat.h>.
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#define SHM_R 0400
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// or S_IWUGO from <linux/stat.h>.
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#define SHM_W 0200
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//==============================================================================
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//======== Commands for shmctl =================================================
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// Lock segment (root only).
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#define SHM_LOCK 11
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// Unlock segment (root only).
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#define SHM_UNLOCK 12
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//==============================================================================
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// Ipcs ctl commands.
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#define SHM_STAT 13
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#define SHM_INFO 14
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#define SHM_STAT_ANY 15
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//======== shm_mode upper byte flags ===========================================
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// segment will be destroyed on last detach.
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#define SHM_DEST 01000
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// Segment will not be swapped.
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#define SHM_LOCKED 02000
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// Segment is mapped via hugetlb.
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#define SHM_HUGETLB 04000
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// Don't check for reservations.
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#define SHM_NORESERVE 010000
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#endif
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#define SHM_RDONLY 010000 ///< Attach read-only else read-write.
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#define SHM_RND 020000 ///< Round attach address to SHMLBA.
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#define SHM_REMAP 040000 ///< Take-over region on attach.
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#define SHM_EXEC 0100000 ///< Execution access.
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#ifdef __KERNEL__
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/// @brief Initializes the shared memory.
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/// @return 0 on success, 1 on failure.
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int shm_init();
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/// @brief Get a System V shared memory identifier.
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/// @param key can be used either to obtain the identifier of a previously
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/// created shared memory, or to create a new one.
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/// @param size of the shared memory, rounded up to a multiple of PAGE_SIZE.
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/// @param shmflg controls the behaviour of the function.
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/// @return the shared memory identifier, -1 on failure, and errno is set to
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/// indicate the error.
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long sys_shmget(key_t key, size_t size, int shmflg);
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/// @brief Attaches the shared memory segment identified by shmid to the address
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/// space of the calling process.
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/// @param shmid the shared memory identifier.
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/// @param shmaddr the attaching address.
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/// @param shmflg controls the behaviour of the function.
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/// @return returns the address of the attached shared memory segment; on error
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/// (void *) -1 is returned, and errno is set to indicate the error.
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void *sys_shmat(int shmid, const void *shmaddr, int shmflg);
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/// @brief Detaches the shared memory segment located at the address specified
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/// by shmaddr from the address space of the calling process
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/// @param shmaddr the address of the shared memory segment.
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/// @return 0 on success, -1 on failure and errno is set to indicate the error.
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long sys_shmdt(const void *shmaddr);
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/// @brief Performs the control operation specified by cmd on the shared memory
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/// segment whose identifier is given in shmid.
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/// @param shmid the shared memory identifier.
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/// @param cmd the command to perform.
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/// @param buf is a pointer to a shmid_ds structure.
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/// @return a non-negative value basedon on the requested operation, -1 on
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/// failure and errno is set to indicate the error.
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long sys_shmctl(int shmid, int cmd, struct shmid_ds *buf);
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#else
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/// @brief Get a System V shared memory identifier.
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/// @param key can be used either to obtain the identifier of a previously
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/// created shared memory, or to create a new one.
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/// @param size of the shared memory, rounded up to a multiple of PAGE_SIZE.
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/// @param shmflg controls the behaviour of the function.
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/// @return the shared memory identifier, -1 on failure, and errno is set to
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/// indicate the error.
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long shmget(key_t key, size_t size, int shmflg);
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/// @brief Attaches the shared memory segment identified by shmid to the address
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/// space of the calling process.
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/// @param shmid the shared memory identifier.
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/// @param shmaddr the attaching address.
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/// @param shmflg controls the behaviour of the function.
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/// @return returns the address of the attached shared memory segment; on error
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/// (void *) -1 is returned, and errno is set to indicate the error.
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void *shmat(int shmid, const void *shmaddr, int shmflg);
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/// @brief Detaches the shared memory segment located at the address specified
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/// by shmaddr from the address space of the calling process
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/// @param shmaddr the address of the shared memory segment.
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/// @return 0 on success, -1 on failure and errno is set to indicate the error.
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long shmdt(const void *shmaddr);
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/// @brief Performs the control operation specified by cmd on the shared memory
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/// segment whose identifier is given in shmid.
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/// @param shmid the shared memory identifier.
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/// @param cmd the command to perform.
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/// @param buf is a pointer to a shmid_ds structure.
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/// @return a non-negative value basedon on the requested operation, -1 on
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/// failure and errno is set to indicate the error.
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long shmctl(int shmid, int cmd, struct shmid_ds *buf);
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#endif
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