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/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
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
sm_shmstop(shm,shmid,owner)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 #ifdef __STDC__
124 int
sm_shmsetowner(int shmid,uid_t uid,gid_t gid,MODE_T mode)125 sm_shmsetowner(int shmid, uid_t uid, gid_t gid, MODE_T mode)
126 #else /* __STDC__ */
127 int
128 sm_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