1 /* 2 * Copyright (c) 2000-2001, 2003, 2005 Sendmail, Inc. and its suppliers. 3 * All rights reserved. 4 * 5 * By using this file, you agree to the terms and conditions set 6 * forth in the LICENSE file which can be found at the top level of 7 * the sendmail distribution. 8 */ 9 10 #pragma ident "%Z%%M% %I% %E% SMI" 11 12 #include <sm/gen.h> 13 SM_RCSID("@(#)$Id: shm.c,v 1.18 2005/02/09 01:54:51 ca Exp $") 14 15 #if SM_CONF_SHM 16 # include <stdlib.h> 17 # include <unistd.h> 18 # include <errno.h> 19 # include <sm/shm.h> 20 21 22 /* 23 ** SM_SHMSTART -- initialize shared memory segment. 24 ** 25 ** Parameters: 26 ** key -- key for shared memory. 27 ** size -- size of segment. 28 ** shmflag -- initial flags. 29 ** shmid -- pointer to return id. 30 ** owner -- create segment. 31 ** 32 ** Returns: 33 ** pointer to shared memory segment, 34 ** NULL on failure. 35 ** 36 ** Side Effects: 37 ** attaches shared memory segment. 38 */ 39 40 void * 41 sm_shmstart(key, size, shmflg, shmid, owner) 42 key_t key; 43 int size; 44 int shmflg; 45 int *shmid; 46 bool owner; 47 { 48 int save_errno; 49 void *shm = SM_SHM_NULL; 50 51 /* default: user/group accessible */ 52 if (shmflg == 0) 53 shmflg = SHM_R|SHM_W|(SHM_R>>3)|(SHM_W>>3); 54 if (owner) 55 shmflg |= IPC_CREAT|IPC_EXCL; 56 *shmid = shmget(key, size, shmflg); 57 if (*shmid < 0) 58 goto error; 59 60 shm = shmat(*shmid, (void *) 0, 0); 61 if (shm == SM_SHM_NULL) 62 goto error; 63 64 return shm; 65 66 error: 67 save_errno = errno; 68 if (shm != SM_SHM_NULL || *shmid >= 0) 69 sm_shmstop(shm, *shmid, owner); 70 *shmid = SM_SHM_NO_ID; 71 errno = save_errno; 72 return (void *) 0; 73 } 74 75 76 /* 77 ** SM_SHMSTOP -- stop using shared memory segment. 78 ** 79 ** Parameters: 80 ** shm -- pointer to shared memory. 81 ** shmid -- id. 82 ** owner -- delete segment. 83 ** 84 ** Returns: 85 ** 0 on success. 86 ** < 0 on failure. 87 ** 88 ** Side Effects: 89 ** detaches (and maybe removes) shared memory segment. 90 */ 91 92 93 int 94 sm_shmstop(shm, shmid, owner) 95 void *shm; 96 int shmid; 97 bool owner; 98 { 99 int r; 100 101 if (shm != SM_SHM_NULL && (r = shmdt(shm)) < 0) 102 return r; 103 if (owner && shmid >= 0 && (r = shmctl(shmid, IPC_RMID, NULL)) < 0) 104 return r; 105 return 0; 106 } 107 108 109 /* 110 ** SM_SHMSETOWNER -- set owner/group/mode of shared memory segment. 111 ** 112 ** Parameters: 113 ** shmid -- id. 114 ** uid -- uid to use 115 ** gid -- gid to use 116 ** mode -- mode to use 117 ** 118 ** Returns: 119 ** 0 on success. 120 ** < 0 on failure. 121 */ 122 123 int 124 sm_shmsetowner(shmid, uid, gid, mode) 125 int shmid; 126 uid_t uid; 127 gid_t gid; 128 mode_t mode; 129 { 130 int r; 131 struct shmid_ds shmid_ds; 132 133 memset(&shmid_ds, 0, sizeof(shmid_ds)); 134 if ((r = shmctl(shmid, IPC_STAT, &shmid_ds)) < 0) 135 return r; 136 shmid_ds.shm_perm.uid = uid; 137 shmid_ds.shm_perm.gid = gid; 138 shmid_ds.shm_perm.mode = mode; 139 if ((r = shmctl(shmid, IPC_SET, &shmid_ds)) < 0) 140 return r; 141 return 0; 142 } 143 #endif /* SM_CONF_SHM */ 144