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 #include <sm/gen.h>
11 SM_RCSID("@(#)$Id: shm.c,v 1.19 2005/07/14 22:34:28 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
sm_shmstop(shm,shmid,owner)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
sm_shmsetowner(shmid,uid,gid,mode)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