xref: /linux-6.15/include/linux/ipc.h (revision 0a3021f4)
1 #ifndef _LINUX_IPC_H
2 #define _LINUX_IPC_H
3 
4 #include <linux/types.h>
5 
6 #define IPC_PRIVATE ((__kernel_key_t) 0)
7 
8 /* Obsolete, used only for backwards compatibility and libc5 compiles */
9 struct ipc_perm
10 {
11 	__kernel_key_t	key;
12 	__kernel_uid_t	uid;
13 	__kernel_gid_t	gid;
14 	__kernel_uid_t	cuid;
15 	__kernel_gid_t	cgid;
16 	__kernel_mode_t	mode;
17 	unsigned short	seq;
18 };
19 
20 /* Include the definition of ipc64_perm */
21 #include <asm/ipcbuf.h>
22 
23 /* resource get request flags */
24 #define IPC_CREAT  00001000   /* create if key is nonexistent */
25 #define IPC_EXCL   00002000   /* fail if key exists */
26 #define IPC_NOWAIT 00004000   /* return error on wait */
27 
28 /* these fields are used by the DIPC package so the kernel as standard
29    should avoid using them if possible */
30 
31 #define IPC_DIPC 00010000  /* make it distributed */
32 #define IPC_OWN  00020000  /* this machine is the DIPC owner */
33 
34 /*
35  * Control commands used with semctl, msgctl and shmctl
36  * see also specific commands in sem.h, msg.h and shm.h
37  */
38 #define IPC_RMID 0     /* remove resource */
39 #define IPC_SET  1     /* set ipc_perm options */
40 #define IPC_STAT 2     /* get ipc_perm options */
41 #define IPC_INFO 3     /* see ipcs */
42 
43 /*
44  * Version flags for semctl, msgctl, and shmctl commands
45  * These are passed as bitflags or-ed with the actual command
46  */
47 #define IPC_OLD 0	/* Old version (no 32-bit UID support on many
48 			   architectures) */
49 #define IPC_64  0x0100  /* New version (support 32-bit UIDs, bigger
50 			   message sizes, etc. */
51 
52 #ifdef __KERNEL__
53 
54 #include <linux/kref.h>
55 #include <linux/spinlock.h>
56 
57 #define IPCMNI 32768  /* <= MAX_INT limit for ipc arrays (including sysctl changes) */
58 
59 /* used by in-kernel data structures */
60 struct kern_ipc_perm
61 {
62 	spinlock_t	lock;
63 	int		deleted;
64 	key_t		key;
65 	uid_t		uid;
66 	gid_t		gid;
67 	uid_t		cuid;
68 	gid_t		cgid;
69 	mode_t		mode;
70 	unsigned long	seq;
71 	void		*security;
72 };
73 
74 struct ipc_ids;
75 struct ipc_namespace {
76 	struct kref	kref;
77 	struct ipc_ids	*ids[3];
78 
79 	int		sem_ctls[4];
80 	int		used_sems;
81 
82 	int		msg_ctlmax;
83 	int		msg_ctlmnb;
84 	int		msg_ctlmni;
85 
86 	size_t		shm_ctlmax;
87 	size_t		shm_ctlall;
88 	int		shm_ctlmni;
89 	int		shm_tot;
90 };
91 
92 extern struct ipc_namespace init_ipc_ns;
93 
94 #ifdef CONFIG_SYSVIPC
95 #define INIT_IPC_NS(ns)		.ns		= &init_ipc_ns,
96 extern struct ipc_namespace *copy_ipcs(unsigned long flags,
97 						struct ipc_namespace *ns);
98 #else
99 #define INIT_IPC_NS(ns)
100 static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
101 						struct ipc_namespace *ns)
102 {
103 	return ns;
104 }
105 #endif
106 
107 #ifdef CONFIG_IPC_NS
108 extern void free_ipc_ns(struct kref *kref);
109 #endif
110 
111 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
112 {
113 #ifdef CONFIG_IPC_NS
114 	if (ns)
115 		kref_get(&ns->kref);
116 #endif
117 	return ns;
118 }
119 
120 static inline void put_ipc_ns(struct ipc_namespace *ns)
121 {
122 #ifdef CONFIG_IPC_NS
123 	kref_put(&ns->kref, free_ipc_ns);
124 #endif
125 }
126 
127 #endif /* __KERNEL__ */
128 
129 #endif /* _LINUX_IPC_H */
130 
131 
132