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> 11SM_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/conf.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 40void * 41sm_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 93int 94sm_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#ifdef __STDC__ 124int 125sm_shmsetowner(int shmid, uid_t uid, gid_t gid, MODE_T mode) 126#else /* __STDC__ */ 127int 128sm_shmsetowner(shmid, uid, gid, mode) 129 int shmid; 130 uid_t uid; 131 gid_t gid; 132 MODE_T mode; 133#endif /* __STDC__ */ 134{ 135 int r; 136 struct shmid_ds shmid_ds; 137 138 memset(&shmid_ds, 0, sizeof(shmid_ds)); 139 if ((r = shmctl(shmid, IPC_STAT, &shmid_ds)) < 0) 140 return r; 141 shmid_ds.shm_perm.uid = uid; 142 shmid_ds.shm_perm.gid = gid; 143 shmid_ds.shm_perm.mode = mode; 144 if ((r = shmctl(shmid, IPC_SET, &shmid_ds)) < 0) 145 return r; 146 return 0; 147} 148#endif /* SM_CONF_SHM */ 149