103 lines
2.0 KiB
C
103 lines
2.0 KiB
C
/*
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* Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers.
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* All rights reserved.
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*
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* By using this file, you agree to the terms and conditions set
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* forth in the LICENSE file which can be found at the top level of
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* the sendmail distribution.
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*/
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#include <sm/gen.h>
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SM_RCSID("@(#)$Id: shm.c,v 1.1.1.1 2002/02/17 21:56:43 gshapiro Exp $")
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#if SM_CONF_SHM
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# include <stdlib.h>
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# include <unistd.h>
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# include <errno.h>
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# include <sm/shm.h>
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/*
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** SM_SHMSTART -- initialize shared memory segment.
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**
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** Parameters:
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** key -- key for shared memory.
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** size -- size of segment.
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** shmflag -- initial flags.
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** shmid -- pointer to return id.
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** owner -- create segment.
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**
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** Returns:
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** pointer to shared memory segment,
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** NULL on failure.
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**
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** Side Effects:
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** attaches shared memory segment.
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*/
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void *
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sm_shmstart(key, size, shmflg, shmid, owner)
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key_t key;
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int size;
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int shmflg;
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int *shmid;
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bool owner;
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{
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int save_errno;
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void *shm = SM_SHM_NULL;
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/* default: user/group accessible */
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if (shmflg == 0)
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shmflg = SHM_R|SHM_W|(SHM_R>>3)|(SHM_W>>3);
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if (owner)
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shmflg |= IPC_CREAT|IPC_EXCL;
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*shmid = shmget(key, size, shmflg);
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if (*shmid < 0)
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goto error;
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shm = shmat(*shmid, (void *) 0, 0);
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if (shm == SM_SHM_NULL)
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goto error;
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return shm;
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error:
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save_errno = errno;
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if (shm != SM_SHM_NULL || *shmid >= 0)
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sm_shmstop(shm, *shmid, owner);
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*shmid = SM_SHM_NO_ID;
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errno = save_errno;
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return (void *) 0;
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}
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/*
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** SM_SHMSTOP -- stop using shared memory segment.
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**
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** Parameters:
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** shm -- pointer to shared memory.
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** shmid -- id.
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** owner -- delete segment.
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**
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** Returns:
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** 0 on success.
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** < 0 on failure.
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**
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** Side Effects:
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** detaches (and maybe removes) shared memory segment.
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*/
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int
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sm_shmstop(shm, shmid, owner)
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void *shm;
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int shmid;
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bool owner;
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{
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int r;
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if (shm != SM_SHM_NULL && (r = shmdt(shm)) < 0)
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return r;
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if (owner && shmid >= 0 && (r = shmctl(shmid, IPC_RMID, NULL)) < 0)
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return r;
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return 0;
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}
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#endif /* SM_CONF_SHM */
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