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 1.19 2005/07/14 22:34:28 ca Exp $") 14 15 #if SM_CONF_SHM 16 # include <stdlib.h> 17 # include <unistd.h> 18 # include <errno.h> 19 # include <sm/string.h> 20 # include <sm/shm.h> 21 22 23 /* 24 ** SM_SHMSTART -- initialize shared memory segment. 25 ** 26 ** Parameters: 27 ** key -- key for shared memory. 28 ** size -- size of segment. 29 ** shmflag -- initial flags. 30 ** shmid -- pointer to return id. 31 ** owner -- create segment. 32 ** 33 ** Returns: 34 ** pointer to shared memory segment, 35 ** NULL on failure. 36 ** 37 ** Side Effects: 38 ** attaches shared memory segment. 39 */ 40 41 void * 42 sm_shmstart(key, size, shmflg, shmid, owner) 43 key_t key; 44 int size; 45 int shmflg; 46 int *shmid; 47 bool owner; 48 { 49 int save_errno; 50 void *shm = SM_SHM_NULL; 51 52 /* default: user/group accessible */ 53 if (shmflg == 0) 54 shmflg = SHM_R|SHM_W|(SHM_R>>3)|(SHM_W>>3); 55 if (owner) 56 shmflg |= IPC_CREAT|IPC_EXCL; 57 *shmid = shmget(key, size, shmflg); 58 if (*shmid < 0) 59 goto error; 60 61 shm = shmat(*shmid, (void *) 0, 0); 62 if (shm == SM_SHM_NULL) 63 goto error; 64 65 return shm; 66 67 error: 68 save_errno = errno; 69 if (shm != SM_SHM_NULL || *shmid >= 0) 70 sm_shmstop(shm, *shmid, owner); 71 *shmid = SM_SHM_NO_ID; 72 errno = save_errno; 73 return (void *) 0; 74 } 75 76 77 /* 78 ** SM_SHMSTOP -- stop using shared memory segment. 79 ** 80 ** Parameters: 81 ** shm -- pointer to shared memory. 82 ** shmid -- id. 83 ** owner -- delete segment. 84 ** 85 ** Returns: 86 ** 0 on success. 87 ** < 0 on failure. 88 ** 89 ** Side Effects: 90 ** detaches (and maybe removes) shared memory segment. 91 */ 92 93 94 int 95 sm_shmstop(shm, shmid, owner) 96 void *shm; 97 int shmid; 98 bool owner; 99 { 100 int r; 101 102 if (shm != SM_SHM_NULL && (r = shmdt(shm)) < 0) 103 return r; 104 if (owner && shmid >= 0 && (r = shmctl(shmid, IPC_RMID, NULL)) < 0) 105 return r; 106 return 0; 107 } 108 109 110 /* 111 ** SM_SHMSETOWNER -- set owner/group/mode of shared memory segment. 112 ** 113 ** Parameters: 114 ** shmid -- id. 115 ** uid -- uid to use 116 ** gid -- gid to use 117 ** mode -- mode to use 118 ** 119 ** Returns: 120 ** 0 on success. 121 ** < 0 on failure. 122 */ 123 124 int 125 sm_shmsetowner(shmid, uid, gid, mode) 126 int shmid; 127 uid_t uid; 128 gid_t gid; 129 mode_t mode; 130 { 131 int r; 132 struct shmid_ds shmid_ds; 133 134 memset(&shmid_ds, 0, sizeof(shmid_ds)); 135 if ((r = shmctl(shmid, IPC_STAT, &shmid_ds)) < 0) 136 return r; 137 shmid_ds.shm_perm.uid = uid; 138 shmid_ds.shm_perm.gid = gid; 139 shmid_ds.shm_perm.mode = mode; 140 if ((r = shmctl(shmid, IPC_SET, &shmid_ds)) < 0) 141 return r; 142 return 0; 143 } 144 #endif /* SM_CONF_SHM */ 145