Commit | Line | Data |
---|---|---|
127f7d76 | 1 | /* uipc_mu_msg.c Melb 4.3 82/12/28 */ |
ce19fd2d RE |
2 | |
3 | #ifdef MUSH | |
4 | #include "../h/param.h" | |
5 | #include "../h/dir.h" | |
6 | #include "../h/user.h" | |
7 | #include "../h/proc.h" | |
8 | ||
9 | /* | |
10 | * Melbourne Trivial IPC mechanism | |
11 | * | |
12 | * This is intended solely to serve for the 4.1bsd MUSH implementation | |
13 | * until a better IPC scheme arrives from somewhere | |
14 | * | |
15 | * If it happens to be useful for other purposes, OK, but users | |
16 | * should be prepared to change at short (no) notice. | |
17 | * This is purposely kept as small as possible, with the expectation | |
18 | * than anything done using this scheme should be able to be | |
19 | * done easily in any other, with possibly a little more legwork. | |
20 | * | |
21 | * NB: we don't go fooling with spl's in here, as it is deliberately | |
22 | * not intended that interrupt level code will ever call this | |
23 | */ | |
24 | ||
25 | mu_msg() | |
26 | { | |
27 | register struct proc *p, *pp; | |
28 | mmsgbuf mb; | |
29 | register struct a { | |
30 | msg_type cmd; | |
31 | int wait; /* bit mask - see mu_msg.h */ | |
32 | mmsgbuf * msgp; | |
33 | } *uap; | |
34 | ||
35 | uap = (struct a *)u.u_ap; | |
36 | p = u.u_procp; | |
37 | ||
38 | for (;;) { /* only loop if cmd == MSG_SNDW */ | |
39 | switch (uap->cmd) { | |
40 | ||
41 | case MSG_ENAB: | |
42 | p->p_msgflgs |= MSGENAB; | |
43 | return; | |
44 | ||
45 | case MSG_DISB: | |
46 | p->p_msgflgs &= ~MSGENAB; | |
47 | /* | |
48 | * Q: what should be done with a pending msg | |
49 | * - for now we will just leave it, proc should | |
50 | * do a MSG_RECV w/o waiting after MSG_DISB | |
51 | */ | |
52 | return; | |
53 | ||
54 | case MSG_RECV: | |
55 | while (!p->p_mb.msg_val && (uap->wait & MSG_W_RCV)) { | |
56 | p->p_msgflgs |= MSGOK; | |
57 | sleep((caddr_t) &p->p_mb, MSGPRI); | |
58 | } | |
127f7d76 SL |
59 | u.u_error = copyout((caddr_t)&p->p_mb, |
60 | (caddr_t)uap->msgp, sizeof(mmsgbuf)); | |
ce19fd2d RE |
61 | p->p_msgflgs &= ~(MSGOK|MSGWRPLY); |
62 | if (p->p_mb.msg_rply) | |
63 | p->p_msgflgs |= MSGRPLY; | |
64 | else { | |
65 | p->p_mb.msg_val = 0; | |
66 | if (p->p_msgflgs & MSGWAIT) { | |
67 | p->p_msgflgs &= ~MSGWAIT; | |
68 | wakeup((caddr_t)&p->p_mb); | |
69 | } | |
70 | } | |
71 | return; | |
72 | ||
73 | case MSG_SEND: | |
74 | case MSG_SNDW: | |
75 | case MSG_RPLY: | |
127f7d76 SL |
76 | u.u_error = copyin((caddr_t)uap->msgp, (caddr_t)&mb, |
77 | sizeof(mmsgbuf)); | |
78 | if (u.u_error) | |
ce19fd2d | 79 | return; |
ce19fd2d RE |
80 | if (uap->cmd == MSG_RPLY) { |
81 | if (!(p->p_msgflgs & MSGRPLY) || | |
82 | mb.msg_pid != p->p_mb.msg_pid) { | |
83 | u.u_error = EINVAL; | |
84 | return; | |
85 | } | |
86 | p->p_mb.msg_val = 0; | |
87 | if (!mb.msg_rply && p->p_msgflgs & MSGWAIT) { | |
88 | p->p_msgflgs &= ~MSGWAIT; | |
89 | wakeup((caddr_t)&p->p_mb); | |
90 | } | |
91 | } else { | |
92 | if (p->p_msgflgs & MSGRPLY) { | |
93 | while (pp = mu_send(&p->p_mb, | |
4f083fd7 | 94 | (int)p->p_mb.msg_pid, 0)) { |
ce19fd2d RE |
95 | pp->p_msgflgs |= MSGWAIT; |
96 | sleep((caddr_t)&pp->p_mb, | |
97 | MSGPRI); | |
98 | } | |
99 | u.u_error = 0; /* not err if exited */ | |
100 | p->p_mb.msg_val = 0; | |
101 | if (!mb.msg_rply && | |
102 | p->p_msgflgs & MSGWAIT) { | |
103 | p->p_msgflgs &= ~MSGWAIT; | |
104 | wakeup((caddr_t)&p->p_mb); | |
105 | } | |
106 | } | |
107 | } | |
108 | p->p_msgflgs &= ~MSGRPLY; | |
109 | if (mb.msg_rply) { | |
110 | if (p->p_mb.msg_val) { | |
111 | u.u_error = ENOSPC; | |
112 | return; | |
113 | } | |
114 | p->p_mb = mb; | |
115 | p->p_mb.msg_rply = 0; | |
116 | p->p_mb.msg_val = 0; | |
117 | p->p_msgflgs |= MSGWRPLY; | |
118 | } | |
119 | mb.msg_uid = u.u_uid; | |
4f083fd7 | 120 | while ((pp = mu_send(&mb, (int)mb.msg_pid, p->p_pid)) && |
ce19fd2d RE |
121 | uap->wait & MSG_W_POST) { |
122 | pp->p_msgflgs |= MSGWAIT; | |
123 | sleep((caddr_t)&pp->p_mb, MSGPRI); | |
124 | } | |
125 | if (pp) | |
126 | u.u_error = EBUSY; | |
127 | if (u.u_error) { | |
128 | if (mb.msg_rply) | |
129 | p->p_msgflgs &= ~MSGWRPLY; | |
130 | return; | |
131 | } | |
132 | if (uap->cmd == MSG_SNDW) { | |
133 | uap->cmd = MSG_RECV; | |
134 | break; | |
135 | } | |
136 | return; | |
137 | ||
138 | default: | |
139 | u.u_error = EINVAL; | |
140 | return; | |
141 | } | |
142 | } | |
143 | } | |
144 | ||
145 | struct proc * | |
146 | mu_send(mp, pid, from) | |
4f083fd7 SL |
147 | register mmsgbuf *mp; |
148 | register int pid, from; | |
ce19fd2d RE |
149 | { |
150 | register struct proc *p; | |
151 | ||
152 | p = pfind(pid); | |
153 | ||
154 | if (p == NULL || p->p_stat == SZOMB || | |
155 | !(p->p_msgflgs & (MSGOK|MSGENAB|MSGWRPLY))) { | |
156 | u.u_error = ESRCH; | |
157 | return((struct proc *)0); | |
158 | } | |
159 | ||
160 | if (p->p_mb.msg_val || | |
161 | from != 0 && p->p_msgflgs&MSGWRPLY && from != p->p_mb.msg_pid) | |
162 | return(p); | |
163 | ||
164 | p->p_mb = *mp; | |
165 | p->p_mb.msg_val = 1; | |
166 | p->p_mb.msg_pid = from; | |
167 | if (from == 0) | |
168 | p->p_mb.msg_rply = 0; | |
169 | if (p->p_msgflgs & MSGOK) | |
170 | wakeup((caddr_t)&p->p_mb); | |
171 | else if (p->p_msgflgs & MSGENAB) | |
172 | psignal(p, SIGMESG); | |
173 | return((struct proc *)0); | |
174 | } | |
175 | ||
176 | msgto(pid, data) | |
177 | int pid; | |
178 | DATA_T data; | |
179 | { | |
180 | register struct proc *p; | |
181 | mmsgbuf mb; | |
182 | ||
183 | mb.msg_uid = 0; /* all msgs from system are from root */ | |
184 | mb.msg_data = data; | |
185 | mb.msg_rply = 0; | |
186 | while (p = mu_send(&mb, pid, u.u_procp->p_pid)) { | |
187 | p->p_msgflgs |= MSGWAIT; | |
188 | sleep((caddr_t)&p->p_mb, MSGPRI); | |
189 | } | |
190 | } | |
191 | #endif |