651971cb72
Currently we allocate 64k space on the user stack and use it the msgbuf for
sys_{msgrcv,msgsnd} for compat and the results are later copied in user [
by copy_in_user]. This patch introduces helper routines for
sys_{msgrcv,msgsnd} as below:
do_msgsnd() : Accepts the mtype and user space ptr to the buffer along with
the msqid and msgflg.
do_msgrcv() : Accepts a kernel space ptr to mtype and a userspace ptr to
the buffer. The mtype has to be copied back the user space msgbuf by the
caller.
These changes avoid the need to allocate the msgsize on the userspace (
thus removing the size limt ) and the overhead of an extra copy_in_user().
Signed-off-by: Suzuki K P <suzuki@in.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
103 lines
3.3 KiB
C
103 lines
3.3 KiB
C
#ifndef _LINUX_MSG_H
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#define _LINUX_MSG_H
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#include <linux/ipc.h>
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/* ipcs ctl commands */
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#define MSG_STAT 11
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#define MSG_INFO 12
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/* msgrcv options */
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#define MSG_NOERROR 010000 /* no error if message is too big */
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#define MSG_EXCEPT 020000 /* recv any msg except of specified type.*/
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/* Obsolete, used only for backwards compatibility and libc5 compiles */
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struct msqid_ds {
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struct ipc_perm msg_perm;
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struct msg *msg_first; /* first message on queue,unused */
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struct msg *msg_last; /* last message in queue,unused */
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__kernel_time_t msg_stime; /* last msgsnd time */
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__kernel_time_t msg_rtime; /* last msgrcv time */
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__kernel_time_t msg_ctime; /* last change time */
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unsigned long msg_lcbytes; /* Reuse junk fields for 32 bit */
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unsigned long msg_lqbytes; /* ditto */
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unsigned short msg_cbytes; /* current number of bytes on queue */
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unsigned short msg_qnum; /* number of messages in queue */
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unsigned short msg_qbytes; /* max number of bytes on queue */
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__kernel_ipc_pid_t msg_lspid; /* pid of last msgsnd */
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__kernel_ipc_pid_t msg_lrpid; /* last receive pid */
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};
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/* Include the definition of msqid64_ds */
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#include <asm/msgbuf.h>
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/* message buffer for msgsnd and msgrcv calls */
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struct msgbuf {
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long mtype; /* type of message */
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char mtext[1]; /* message text */
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};
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/* buffer for msgctl calls IPC_INFO, MSG_INFO */
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struct msginfo {
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int msgpool;
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int msgmap;
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int msgmax;
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int msgmnb;
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int msgmni;
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int msgssz;
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int msgtql;
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unsigned short msgseg;
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};
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#define MSGMNI 16 /* <= IPCMNI */ /* max # of msg queue identifiers */
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#define MSGMAX 8192 /* <= INT_MAX */ /* max size of message (bytes) */
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#define MSGMNB 16384 /* <= INT_MAX */ /* default max size of a message queue */
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/* unused */
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#define MSGPOOL (MSGMNI*MSGMNB/1024) /* size in kilobytes of message pool */
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#define MSGTQL MSGMNB /* number of system message headers */
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#define MSGMAP MSGMNB /* number of entries in message map */
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#define MSGSSZ 16 /* message segment size */
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#define __MSGSEG ((MSGPOOL*1024)/ MSGSSZ) /* max no. of segments */
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#define MSGSEG (__MSGSEG <= 0xffff ? __MSGSEG : 0xffff)
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#ifdef __KERNEL__
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#include <linux/list.h>
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/* one msg_msg structure for each message */
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struct msg_msg {
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struct list_head m_list;
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long m_type;
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int m_ts; /* message text size */
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struct msg_msgseg* next;
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void *security;
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/* the actual message follows immediately */
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};
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/* one msq_queue structure for each present queue on the system */
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struct msg_queue {
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struct kern_ipc_perm q_perm;
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int q_id;
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time_t q_stime; /* last msgsnd time */
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time_t q_rtime; /* last msgrcv time */
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time_t q_ctime; /* last change time */
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unsigned long q_cbytes; /* current number of bytes on queue */
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unsigned long q_qnum; /* number of messages in queue */
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unsigned long q_qbytes; /* max number of bytes on queue */
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pid_t q_lspid; /* pid of last msgsnd */
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pid_t q_lrpid; /* last receive pid */
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struct list_head q_messages;
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struct list_head q_receivers;
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struct list_head q_senders;
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};
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/* Helper routines for sys_msgsnd and sys_msgrcv */
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extern long do_msgsnd(int msqid, long mtype, void __user *mtext,
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size_t msgsz, int msgflg);
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extern long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
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size_t msgsz, long msgtyp, int msgflg);
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#endif /* __KERNEL__ */
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#endif /* _LINUX_MSG_H */
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