1 /* 2 * Copyright (c) 2000-2001, 2003, 2005 Proofpoint, 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 #include <sm/gen.h> 11 SM_RCSID("@(#)$Id: shm.c,v 1.20 2013/11/22 20:51:43 ca Exp $") 12 13 #if SM_CONF_SHM 14 # include <stdlib.h> 15 # include <unistd.h> 16 # include <errno.h> 17 # include <sm/string.h> 18 # include <sm/shm.h> 19 20 21 /* 22 ** SM_SHMSTART -- initialize shared memory segment. 23 ** 24 ** Parameters: 25 ** key -- key for shared memory. 26 ** size -- size of segment. 27 ** shmflag -- initial flags. 28 ** shmid -- pointer to return id. 29 ** owner -- create segment. 30 ** 31 ** Returns: 32 ** pointer to shared memory segment, 33 ** NULL on failure. 34 ** 35 ** Side Effects: 36 ** attaches shared memory segment. 37 */ 38 39 void * 40 sm_shmstart(key, size, shmflg, shmid, owner) 41 key_t key; 42 int size; 43 int shmflg; 44 int *shmid; 45 bool owner; 46 { 47 int save_errno; 48 void *shm = SM_SHM_NULL; 49 50 /* default: user/group accessible */ 51 if (shmflg == 0) 52 shmflg = SHM_R|SHM_W|(SHM_R>>3)|(SHM_W>>3); 53 if (owner) 54 shmflg |= IPC_CREAT|IPC_EXCL; 55 *shmid = shmget(key, size, shmflg); 56 if (*shmid < 0) 57 goto error; 58 59 shm = shmat(*shmid, (void *) 0, 0); 60 if (shm == SM_SHM_NULL) 61 goto error; 62 63 return shm; 64 65 error: 66 save_errno = errno; 67 if (shm != SM_SHM_NULL || *shmid >= 0) 68 sm_shmstop(shm, *shmid, owner); 69 *shmid = SM_SHM_NO_ID; 70 errno = save_errno; 71 return (void *) 0; 72 } 73 74 75 /* 76 ** SM_SHMSTOP -- stop using shared memory segment. 77 ** 78 ** Parameters: 79 ** shm -- pointer to shared memory. 80 ** shmid -- id. 81 ** owner -- delete segment. 82 ** 83 ** Returns: 84 ** 0 on success. 85 ** < 0 on failure. 86 ** 87 ** Side Effects: 88 ** detaches (and maybe removes) shared memory segment. 89 */ 90 91 92 int 93 sm_shmstop(shm, shmid, owner) 94 void *shm; 95 int shmid; 96 bool owner; 97 { 98 int r; 99 100 if (shm != SM_SHM_NULL && (r = shmdt(shm)) < 0) 101 return r; 102 if (owner && shmid >= 0 && (r = shmctl(shmid, IPC_RMID, NULL)) < 0) 103 return r; 104 return 0; 105 } 106 107 108 /* 109 ** SM_SHMSETOWNER -- set owner/group/mode of shared memory segment. 110 ** 111 ** Parameters: 112 ** shmid -- id. 113 ** uid -- uid to use 114 ** gid -- gid to use 115 ** mode -- mode to use 116 ** 117 ** Returns: 118 ** 0 on success. 119 ** < 0 on failure. 120 */ 121 122 int 123 sm_shmsetowner(shmid, uid, gid, mode) 124 int shmid; 125 uid_t uid; 126 gid_t gid; 127 mode_t mode; 128 { 129 int r; 130 struct shmid_ds shmid_ds; 131 132 memset(&shmid_ds, 0, sizeof(shmid_ds)); 133 if ((r = shmctl(shmid, IPC_STAT, &shmid_ds)) < 0) 134 return r; 135 shmid_ds.shm_perm.uid = uid; 136 shmid_ds.shm_perm.gid = gid; 137 shmid_ds.shm_perm.mode = mode; 138 if ((r = shmctl(shmid, IPC_SET, &shmid_ds)) < 0) 139 return r; 140 return 0; 141 } 142 #endif /* SM_CONF_SHM */ 143