1 | /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ |
2 | #ifndef _UAPI_LINUX_MSG_H |
3 | #define _UAPI_LINUX_MSG_H |
4 | |
5 | #include <linux/ipc.h> |
6 | |
7 | /* ipcs ctl commands */ |
8 | #define MSG_STAT 11 |
9 | #define MSG_INFO 12 |
10 | #define MSG_STAT_ANY 13 |
11 | |
12 | /* msgrcv options */ |
13 | #define MSG_NOERROR 010000 /* no error if message is too big */ |
14 | #define MSG_EXCEPT 020000 /* recv any msg except of specified type.*/ |
15 | #define MSG_COPY 040000 /* copy (not remove) all queue messages */ |
16 | |
17 | /* Obsolete, used only for backwards compatibility and libc5 compiles */ |
18 | struct msqid_ds { |
19 | struct ipc_perm msg_perm; |
20 | struct msg *msg_first; /* first message on queue,unused */ |
21 | struct msg *msg_last; /* last message in queue,unused */ |
22 | __kernel_old_time_t msg_stime; /* last msgsnd time */ |
23 | __kernel_old_time_t msg_rtime; /* last msgrcv time */ |
24 | __kernel_old_time_t msg_ctime; /* last change time */ |
25 | unsigned long msg_lcbytes; /* Reuse junk fields for 32 bit */ |
26 | unsigned long msg_lqbytes; /* ditto */ |
27 | unsigned short msg_cbytes; /* current number of bytes on queue */ |
28 | unsigned short msg_qnum; /* number of messages in queue */ |
29 | unsigned short msg_qbytes; /* max number of bytes on queue */ |
30 | __kernel_ipc_pid_t msg_lspid; /* pid of last msgsnd */ |
31 | __kernel_ipc_pid_t msg_lrpid; /* last receive pid */ |
32 | }; |
33 | |
34 | /* Include the definition of msqid64_ds */ |
35 | #include <asm/msgbuf.h> |
36 | |
37 | /* message buffer for msgsnd and msgrcv calls */ |
38 | struct msgbuf { |
39 | __kernel_long_t mtype; /* type of message */ |
40 | char mtext[1]; /* message text */ |
41 | }; |
42 | |
43 | /* buffer for msgctl calls IPC_INFO, MSG_INFO */ |
44 | struct msginfo { |
45 | int msgpool; |
46 | int msgmap; |
47 | int msgmax; |
48 | int msgmnb; |
49 | int msgmni; |
50 | int msgssz; |
51 | int msgtql; |
52 | unsigned short msgseg; |
53 | }; |
54 | |
55 | /* |
56 | * MSGMNI, MSGMAX and MSGMNB are default values which can be |
57 | * modified by sysctl. |
58 | * |
59 | * MSGMNI is the upper limit for the number of messages queues per |
60 | * namespace. |
61 | * It has been chosen to be as large possible without facilitating |
62 | * scenarios where userspace causes overflows when adjusting the limits via |
63 | * operations of the form retrieve current limit; add X; update limit". |
64 | * |
65 | * MSGMNB is the default size of a new message queue. Non-root tasks can |
66 | * decrease the size with msgctl(IPC_SET), root tasks |
67 | * (actually: CAP_SYS_RESOURCE) can both increase and decrease the queue |
68 | * size. The optimal value is application dependent. |
69 | * 16384 is used because it was always used (since 0.99.10) |
70 | * |
71 | * MAXMAX is the maximum size of an individual message, it's a global |
72 | * (per-namespace) limit that applies for all message queues. |
73 | * It's set to 1/2 of MSGMNB, to ensure that at least two messages fit into |
74 | * the queue. This is also an arbitrary choice (since 2.6.0). |
75 | */ |
76 | |
77 | #define MSGMNI 32000 /* <= IPCMNI */ /* max # of msg queue identifiers */ |
78 | #define MSGMAX 8192 /* <= INT_MAX */ /* max size of message (bytes) */ |
79 | #define MSGMNB 16384 /* <= INT_MAX */ /* default max size of a message queue */ |
80 | |
81 | /* unused */ |
82 | #define MSGPOOL (MSGMNI * MSGMNB / 1024) /* size in kbytes of message pool */ |
83 | #define MSGTQL MSGMNB /* number of system message headers */ |
84 | #define MSGMAP MSGMNB /* number of entries in message map */ |
85 | #define MSGSSZ 16 /* message segment size */ |
86 | #define __MSGSEG ((MSGPOOL * 1024) / MSGSSZ) /* max no. of segments */ |
87 | #define MSGSEG (__MSGSEG <= 0xffff ? __MSGSEG : 0xffff) |
88 | |
89 | |
90 | #endif /* _UAPI_LINUX_MSG_H */ |
91 | |