projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| ce19fd2d RE |
1 | /* uipc_mu_msg.c Melb 4.1 82/07/16 */ |
| 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 | } | |
| 59 | if (copyout((caddr_t)&p->p_mb, (caddr_t)uap->msgp, | |
| 60 | sizeof(mmsgbuf))) | |
| 61 | u.u_error = EFAULT; | |
| 62 | p->p_msgflgs &= ~(MSGOK|MSGWRPLY); | |
| 63 | if (p->p_mb.msg_rply) | |
| 64 | p->p_msgflgs |= MSGRPLY; | |
| 65 | else { | |
| 66 | p->p_mb.msg_val = 0; | |
| 67 | if (p->p_msgflgs & MSGWAIT) { | |
| 68 | p->p_msgflgs &= ~MSGWAIT; | |
| 69 | wakeup((caddr_t)&p->p_mb); | |
| 70 | } | |
| 71 | } | |
| 72 | return; | |
| 73 | ||
| 74 | case MSG_SEND: | |
| 75 | case MSG_SNDW: | |
| 76 | case MSG_RPLY: | |
| 77 | if (copyin((caddr_t)uap->msgp, (caddr_t)&mb, | |
| 78 | sizeof(mmsgbuf))) { | |
| 79 | u.u_error = EFAULT; | |
| 80 | return; | |
| 81 | } | |
| 82 | if (uap->cmd == MSG_RPLY) { | |
| 83 | if (!(p->p_msgflgs & MSGRPLY) || | |
| 84 | mb.msg_pid != p->p_mb.msg_pid) { | |
| 85 | u.u_error = EINVAL; | |
| 86 | return; | |
| 87 | } | |
| 88 | p->p_mb.msg_val = 0; | |
| 89 | if (!mb.msg_rply && p->p_msgflgs & MSGWAIT) { | |
| 90 | p->p_msgflgs &= ~MSGWAIT; | |
| 91 | wakeup((caddr_t)&p->p_mb); | |
| 92 | } | |
| 93 | } else { | |
| 94 | if (p->p_msgflgs & MSGRPLY) { | |
| 95 | while (pp = mu_send(&p->p_mb, | |
| 96 | p->p_mb.msg_pid, 0)) { | |
| 97 | pp->p_msgflgs |= MSGWAIT; | |
| 98 | sleep((caddr_t)&pp->p_mb, | |
| 99 | MSGPRI); | |
| 100 | } | |
| 101 | u.u_error = 0; /* not err if exited */ | |
| 102 | p->p_mb.msg_val = 0; | |
| 103 | if (!mb.msg_rply && | |
| 104 | p->p_msgflgs & MSGWAIT) { | |
| 105 | p->p_msgflgs &= ~MSGWAIT; | |
| 106 | wakeup((caddr_t)&p->p_mb); | |
| 107 | } | |
| 108 | } | |
| 109 | } | |
| 110 | p->p_msgflgs &= ~MSGRPLY; | |
| 111 | if (mb.msg_rply) { | |
| 112 | if (p->p_mb.msg_val) { | |
| 113 | u.u_error = ENOSPC; | |
| 114 | return; | |
| 115 | } | |
| 116 | p->p_mb = mb; | |
| 117 | p->p_mb.msg_rply = 0; | |
| 118 | p->p_mb.msg_val = 0; | |
| 119 | p->p_msgflgs |= MSGWRPLY; | |
| 120 | } | |
| 121 | mb.msg_uid = u.u_uid; | |
| 122 | while ((pp = mu_send(&mb, mb.msg_pid, p->p_pid)) && | |
| 123 | uap->wait & MSG_W_POST) { | |
| 124 | pp->p_msgflgs |= MSGWAIT; | |
| 125 | sleep((caddr_t)&pp->p_mb, MSGPRI); | |
| 126 | } | |
| 127 | if (pp) | |
| 128 | u.u_error = EBUSY; | |
| 129 | if (u.u_error) { | |
| 130 | if (mb.msg_rply) | |
| 131 | p->p_msgflgs &= ~MSGWRPLY; | |
| 132 | return; | |
| 133 | } | |
| 134 | if (uap->cmd == MSG_SNDW) { | |
| 135 | uap->cmd = MSG_RECV; | |
| 136 | break; | |
| 137 | } | |
| 138 | return; | |
| 139 | ||
| 140 | default: | |
| 141 | u.u_error = EINVAL; | |
| 142 | return; | |
| 143 | } | |
| 144 | } | |
| 145 | } | |
| 146 | ||
| 147 | struct proc * | |
| 148 | mu_send(mp, pid, from) | |
| 149 | register mmsgbuf *mp; | |
| 150 | register int pid; | |
| 151 | register int from; | |
| 152 | { | |
| 153 | register struct proc *p; | |
| 154 | ||
| 155 | p = pfind(pid); | |
| 156 | ||
| 157 | if (p == NULL || p->p_stat == SZOMB || | |
| 158 | !(p->p_msgflgs & (MSGOK|MSGENAB|MSGWRPLY))) { | |
| 159 | u.u_error = ESRCH; | |
| 160 | return((struct proc *)0); | |
| 161 | } | |
| 162 | ||
| 163 | if (p->p_mb.msg_val || | |
| 164 | from != 0 && p->p_msgflgs&MSGWRPLY && from != p->p_mb.msg_pid) | |
| 165 | return(p); | |
| 166 | ||
| 167 | p->p_mb = *mp; | |
| 168 | p->p_mb.msg_val = 1; | |
| 169 | p->p_mb.msg_pid = from; | |
| 170 | if (from == 0) | |
| 171 | p->p_mb.msg_rply = 0; | |
| 172 | if (p->p_msgflgs & MSGOK) | |
| 173 | wakeup((caddr_t)&p->p_mb); | |
| 174 | else if (p->p_msgflgs & MSGENAB) | |
| 175 | psignal(p, SIGMESG); | |
| 176 | return((struct proc *)0); | |
| 177 | } | |
| 178 | ||
| 179 | msgto(pid, data) | |
| 180 | int pid; | |
| 181 | DATA_T data; | |
| 182 | { | |
| 183 | register struct proc *p; | |
| 184 | mmsgbuf mb; | |
| 185 | ||
| 186 | mb.msg_uid = 0; /* all msgs from system are from root */ | |
| 187 | mb.msg_data = data; | |
| 188 | mb.msg_rply = 0; | |
| 189 | while (p = mu_send(&mb, pid, u.u_procp->p_pid)) { | |
| 190 | p->p_msgflgs |= MSGWAIT; | |
| 191 | sleep((caddr_t)&p->p_mb, MSGPRI); | |
| 192 | } | |
| 193 | } | |
| 194 | #endif |