1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
|
#ifndef IPC_H
#define IPC_H
/* This header file defines constants for MINIX inter-process communication.
* These definitions are used in the file proc.c.
*/
#include <minix/com.h>
#include <minix/ipcconst.h>
/* Masks and flags for system calls. */
#define NON_BLOCKING 0x0080 /* do not block if target not ready */
#define FROM_KERNEL 0x0100 /* message from kernel on behalf of a process */
#define WILLRECEIVE(src_e,dst_ptr,m_src_v,m_src_p) \
((RTS_ISSET(dst_ptr, RTS_RECEIVING) && \
!RTS_ISSET(dst_ptr, RTS_SENDING)) && \
CANRECEIVE(dst_ptr->p_getfrom_e,src_e,dst_ptr,m_src_v,m_src_p))
#define CANRECEIVE(receive_e,src_e,dst_ptr,m_src_v,m_src_p) \
(((receive_e) == ANY || (receive_e) == (src_e)) && \
(priv(dst_ptr)->s_ipcf == NULL || \
allow_ipc_filtered_msg(dst_ptr,src_e,m_src_v,m_src_p)))
/* IPC status code macros. */
#define IPC_STATUS_GET(p) ((p)->p_reg.IPC_STATUS_REG)
#define IPC_STATUS_CLEAR(p) ((p)->p_reg.IPC_STATUS_REG = 0)
/*
* XXX: the following check is used to set the status code only on RECEIVE.
* SENDREC is not currently atomic for user processes. A process can return
* from SENDREC in a different context than the original when a Posix signal
* handler gets executed. For this reason, it is not safe to manipulate
* the context (i.e. registers) when a process is blocked on a SENDREC.
* Unfortunately, avoiding setting the status code for SENDREC doesn't solve
* the problem entirely because in rare situations it is still necessary to
* override retreg dynamically (and possibly in a different context).
* A possible reliable solution is to improve our Posix signal handling
* implementation and guarantee SENDREC atomicity w.r.t. the process context.
*/
#define IPC_STATUS_ADD(p, m) do { \
if(!((p)->p_misc_flags & MF_REPLY_PEND)) { \
(p)->p_reg.IPC_STATUS_REG |= (m); \
} \
} while(0)
#define IPC_STATUS_ADD_CALL(p, call) \
IPC_STATUS_ADD(p, IPC_STATUS_CALL_TO(call))
#define IPC_STATUS_ADD_FLAGS(p, flags) \
IPC_STATUS_ADD(p, IPC_STATUS_FLAGS(flags))
#endif /* IPC_H */
|
