/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ #ifndef _UAPI_LINUX_MSG_H #define _UAPI_LINUX_MSG_H #include <linux/ipc.h> /* ipcs ctl commands */ #define MSG_STAT … #define MSG_INFO … #define MSG_STAT_ANY … /* msgrcv options */ #define MSG_NOERROR … #define MSG_EXCEPT … #define MSG_COPY … /* Obsolete, used only for backwards compatibility and libc5 compiles */ struct msqid_ds { … }; /* Include the definition of msqid64_ds */ #include <asm/msgbuf.h> /* message buffer for msgsnd and msgrcv calls */ struct msgbuf { … }; /* buffer for msgctl calls IPC_INFO, MSG_INFO */ struct msginfo { … }; /* * MSGMNI, MSGMAX and MSGMNB are default values which can be * modified by sysctl. * * MSGMNI is the upper limit for the number of messages queues per * namespace. * It has been chosen to be as large possible without facilitating * scenarios where userspace causes overflows when adjusting the limits via * operations of the form retrieve current limit; add X; update limit". * * MSGMNB is the default size of a new message queue. Non-root tasks can * decrease the size with msgctl(IPC_SET), root tasks * (actually: CAP_SYS_RESOURCE) can both increase and decrease the queue * size. The optimal value is application dependent. * 16384 is used because it was always used (since 0.99.10) * * MAXMAX is the maximum size of an individual message, it's a global * (per-namespace) limit that applies for all message queues. * It's set to 1/2 of MSGMNB, to ensure that at least two messages fit into * the queue. This is also an arbitrary choice (since 2.6.0). */ #define MSGMNI … #define MSGMAX … #define MSGMNB … /* unused */ #define MSGPOOL … #define MSGTQL … #define MSGMAP … #define MSGSSZ … #define __MSGSEG … #define MSGSEG … #endif /* _UAPI_LINUX_MSG_H */
Codebase Browser
linux