xref: /linux-6.15/include/linux/ipc.h (revision 73ea4130)
1 #ifndef _LINUX_IPC_H
2 #define _LINUX_IPC_H
3 
4 #include <linux/types.h>
5 #include <linux/kref.h>
6 
7 #define IPC_PRIVATE ((__kernel_key_t) 0)
8 
9 /* Obsolete, used only for backwards compatibility and libc5 compiles */
10 struct ipc_perm
11 {
12 	__kernel_key_t	key;
13 	__kernel_uid_t	uid;
14 	__kernel_gid_t	gid;
15 	__kernel_uid_t	cuid;
16 	__kernel_gid_t	cgid;
17 	__kernel_mode_t	mode;
18 	unsigned short	seq;
19 };
20 
21 /* Include the definition of ipc64_perm */
22 #include <asm/ipcbuf.h>
23 
24 /* resource get request flags */
25 #define IPC_CREAT  00001000   /* create if key is nonexistent */
26 #define IPC_EXCL   00002000   /* fail if key exists */
27 #define IPC_NOWAIT 00004000   /* return error on wait */
28 
29 /* these fields are used by the DIPC package so the kernel as standard
30    should avoid using them if possible */
31 
32 #define IPC_DIPC 00010000  /* make it distributed */
33 #define IPC_OWN  00020000  /* this machine is the DIPC owner */
34 
35 /*
36  * Control commands used with semctl, msgctl and shmctl
37  * see also specific commands in sem.h, msg.h and shm.h
38  */
39 #define IPC_RMID 0     /* remove resource */
40 #define IPC_SET  1     /* set ipc_perm options */
41 #define IPC_STAT 2     /* get ipc_perm options */
42 #define IPC_INFO 3     /* see ipcs */
43 
44 /*
45  * Version flags for semctl, msgctl, and shmctl commands
46  * These are passed as bitflags or-ed with the actual command
47  */
48 #define IPC_OLD 0	/* Old version (no 32-bit UID support on many
49 			   architectures) */
50 #define IPC_64  0x0100  /* New version (support 32-bit UIDs, bigger
51 			   message sizes, etc. */
52 
53 #ifdef __KERNEL__
54 
55 #define IPCMNI 32768  /* <= MAX_INT limit for ipc arrays (including sysctl changes) */
56 
57 /* used by in-kernel data structures */
58 struct kern_ipc_perm
59 {
60 	spinlock_t	lock;
61 	int		deleted;
62 	key_t		key;
63 	uid_t		uid;
64 	gid_t		gid;
65 	uid_t		cuid;
66 	gid_t		cgid;
67 	mode_t		mode;
68 	unsigned long	seq;
69 	void		*security;
70 };
71 
72 struct ipc_ids;
73 struct ipc_namespace {
74 	struct kref	kref;
75 	struct ipc_ids	*ids[3];
76 
77 	int		sem_ctls[4];
78 	int		used_sems;
79 
80 	int		msg_ctlmax;
81 	int		msg_ctlmnb;
82 	int		msg_ctlmni;
83 
84 	size_t		shm_ctlmax;
85 	size_t		shm_ctlall;
86 	int		shm_ctlmni;
87 	int		shm_tot;
88 };
89 
90 extern struct ipc_namespace init_ipc_ns;
91 
92 #ifdef CONFIG_SYSVIPC
93 #define INIT_IPC_NS(ns)		.ns		= &init_ipc_ns,
94 #else
95 #define INIT_IPC_NS(ns)
96 #endif
97 
98 #ifdef CONFIG_IPC_NS
99 extern void free_ipc_ns(struct kref *kref);
100 extern int copy_ipcs(unsigned long flags, struct task_struct *tsk);
101 extern int unshare_ipcs(unsigned long flags, struct ipc_namespace **ns);
102 #else
103 static inline int copy_ipcs(unsigned long flags, struct task_struct *tsk)
104 {
105 	return 0;
106 }
107 #endif
108 
109 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
110 {
111 #ifdef CONFIG_IPC_NS
112 	if (ns)
113 		kref_get(&ns->kref);
114 #endif
115 	return ns;
116 }
117 
118 static inline void put_ipc_ns(struct ipc_namespace *ns)
119 {
120 #ifdef CONFIG_IPC_NS
121 	kref_put(&ns->kref, free_ipc_ns);
122 #endif
123 }
124 
125 #endif /* __KERNEL__ */
126 
127 #endif /* _LINUX_IPC_H */
128 
129 
130