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>
13SM_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
41void *
42sm_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
94int
95sm_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
124int
125sm_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