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