| 1 | /* |
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| 2 | * Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers. |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * By using this file, you agree to the terms and conditions set |
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| 6 | * forth in the LICENSE file which can be found at the top level of |
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| 7 | * the sendmail distribution. |
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| 8 | */ |
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| 9 | |
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| 10 | #include <sm/gen.h> |
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| 11 | SM_RCSID("@(#)$Id: shm.c,v 1.1.1.1 2003-04-08 15:06:37 zacheiss Exp $") |
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| 12 | |
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| 13 | #if SM_CONF_SHM |
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| 14 | # include <stdlib.h> |
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| 15 | # include <unistd.h> |
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| 16 | # include <errno.h> |
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| 17 | # include <sm/shm.h> |
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| 18 | |
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| 19 | /* |
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| 20 | ** SM_SHMSTART -- initialize shared memory segment. |
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| 21 | ** |
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| 22 | ** Parameters: |
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| 23 | ** key -- key for shared memory. |
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| 24 | ** size -- size of segment. |
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| 25 | ** shmflag -- initial flags. |
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| 26 | ** shmid -- pointer to return id. |
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| 27 | ** owner -- create segment. |
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| 28 | ** |
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| 29 | ** Returns: |
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| 30 | ** pointer to shared memory segment, |
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| 31 | ** NULL on failure. |
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| 32 | ** |
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| 33 | ** Side Effects: |
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| 34 | ** attaches shared memory segment. |
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| 35 | */ |
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| 36 | |
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| 37 | void * |
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| 38 | sm_shmstart(key, size, shmflg, shmid, owner) |
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| 39 | key_t key; |
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| 40 | int size; |
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| 41 | int shmflg; |
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| 42 | int *shmid; |
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| 43 | bool owner; |
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| 44 | { |
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| 45 | int save_errno; |
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| 46 | void *shm = SM_SHM_NULL; |
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| 47 | |
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| 48 | /* default: user/group accessible */ |
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| 49 | if (shmflg == 0) |
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| 50 | shmflg = SHM_R|SHM_W|(SHM_R>>3)|(SHM_W>>3); |
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| 51 | if (owner) |
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| 52 | shmflg |= IPC_CREAT|IPC_EXCL; |
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| 53 | *shmid = shmget(key, size, shmflg); |
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| 54 | if (*shmid < 0) |
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| 55 | goto error; |
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| 56 | |
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| 57 | shm = shmat(*shmid, (void *) 0, 0); |
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| 58 | if (shm == SM_SHM_NULL) |
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| 59 | goto error; |
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| 60 | |
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| 61 | return shm; |
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| 62 | |
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| 63 | error: |
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| 64 | save_errno = errno; |
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| 65 | if (shm != SM_SHM_NULL || *shmid >= 0) |
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| 66 | sm_shmstop(shm, *shmid, owner); |
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| 67 | *shmid = SM_SHM_NO_ID; |
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| 68 | errno = save_errno; |
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| 69 | return (void *) 0; |
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| 70 | } |
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| 71 | |
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| 72 | /* |
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| 73 | ** SM_SHMSTOP -- stop using shared memory segment. |
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| 74 | ** |
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| 75 | ** Parameters: |
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| 76 | ** shm -- pointer to shared memory. |
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| 77 | ** shmid -- id. |
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| 78 | ** owner -- delete segment. |
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| 79 | ** |
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| 80 | ** Returns: |
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| 81 | ** 0 on success. |
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| 82 | ** < 0 on failure. |
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| 83 | ** |
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| 84 | ** Side Effects: |
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| 85 | ** detaches (and maybe removes) shared memory segment. |
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| 86 | */ |
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| 87 | |
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| 88 | int |
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| 89 | sm_shmstop(shm, shmid, owner) |
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| 90 | void *shm; |
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| 91 | int shmid; |
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| 92 | bool owner; |
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| 93 | { |
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| 94 | int r; |
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| 95 | |
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| 96 | if (shm != SM_SHM_NULL && (r = shmdt(shm)) < 0) |
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| 97 | return r; |
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| 98 | if (owner && shmid >= 0 && (r = shmctl(shmid, IPC_RMID, NULL)) < 0) |
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| 99 | return r; |
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| 100 | return 0; |
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| 101 | } |
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| 102 | #endif /* SM_CONF_SHM */ |
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