| 1 | /* |
| 2 | * Copyright (c) 1983 Regents of the University of California. |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms are permitted |
| 6 | * provided that the above copyright notice and this paragraph are |
| 7 | * duplicated in all such forms and that any documentation, |
| 8 | * advertising materials, and other materials related to such |
| 9 | * distribution and use acknowledge that the software was developed |
| 10 | * by the University of California, Berkeley. The name of the |
| 11 | * University may not be used to endorse or promote products derived |
| 12 | * from this software without specific prior written permission. |
| 13 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
| 14 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
| 15 | * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
| 16 | */ |
| 17 | |
| 18 | #ifndef lint |
| 19 | static char sccsid[] = "@(#)wwiomux.c 3.19 (Berkeley) %G%"; |
| 20 | #endif /* not lint */ |
| 21 | |
| 22 | #include "ww.h" |
| 23 | #include <sys/time.h> |
| 24 | #include <sys/types.h> |
| 25 | #include <fcntl.h> |
| 26 | |
| 27 | /* |
| 28 | * Multiple window output handler. |
| 29 | * The idea is to copy window outputs to the terminal, via the |
| 30 | * display package. We try to give the top most window highest |
| 31 | * priority. The only return condition is when there is keyboard |
| 32 | * input or when a child process dies which are serviced by signal |
| 33 | * catchers (wwrint() and wwchild()). |
| 34 | * When there's nothing to do, we sleep in a select(). |
| 35 | * This can be done better with interrupt driven io. But that's |
| 36 | * not supported on ptys, yet. |
| 37 | * The history of this routine is interesting. |
| 38 | */ |
| 39 | wwiomux() |
| 40 | { |
| 41 | register struct ww *w; |
| 42 | fd_set imask; |
| 43 | register n; |
| 44 | register char *p; |
| 45 | char c; |
| 46 | struct timeval tv; |
| 47 | char noblock; |
| 48 | |
| 49 | for (;;) { |
| 50 | if (wwinterrupt()) { |
| 51 | wwclrintr(); |
| 52 | return; |
| 53 | } |
| 54 | |
| 55 | FD_ZERO(&imask); |
| 56 | noblock = 0; |
| 57 | for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) { |
| 58 | if (w->ww_pty < 0) |
| 59 | continue; |
| 60 | if (w->ww_obq < w->ww_obe) |
| 61 | FD_SET(w->ww_pty, &imask); |
| 62 | if (w->ww_obq > w->ww_obp && !w->ww_stopped) |
| 63 | noblock = 1; |
| 64 | } |
| 65 | |
| 66 | if (!noblock) { |
| 67 | if (wwcurwin != 0) |
| 68 | wwcurtowin(wwcurwin); |
| 69 | wwupdate(); |
| 70 | wwflush(); |
| 71 | setjmp(wwjmpbuf); |
| 72 | wwsetjmp = 1; |
| 73 | if (wwinterrupt()) { |
| 74 | wwsetjmp = 0; |
| 75 | wwclrintr(); |
| 76 | return; |
| 77 | } |
| 78 | /* |
| 79 | * Defensive code. If somebody else (for example, |
| 80 | * wall) clears the ASYNC flag on us, we will block |
| 81 | * forever. So we need a finite timeout and set |
| 82 | * the flag again. Anything more clever will probably |
| 83 | * need even more system calls. (This is a bug |
| 84 | * in the kernel.) |
| 85 | * I don't like this one bit. |
| 86 | */ |
| 87 | fcntl(0, F_SETFL, wwnewtty.ww_fflags); |
| 88 | tv.tv_sec = 30; |
| 89 | } else |
| 90 | tv.tv_sec = 0; |
| 91 | tv.tv_usec = 0; |
| 92 | wwnselect++; |
| 93 | n = select(wwdtablesize, &imask, (fd_set *)0, (fd_set *)0, &tv); |
| 94 | wwsetjmp = 0; |
| 95 | |
| 96 | if (n < 0) |
| 97 | wwnselecte++; |
| 98 | else if (n == 0) |
| 99 | wwnselectz++; |
| 100 | else |
| 101 | for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) { |
| 102 | if (w->ww_pty < 0 || |
| 103 | !FD_ISSET(w->ww_pty, &imask)) |
| 104 | continue; |
| 105 | wwnwread++; |
| 106 | p = w->ww_obq; |
| 107 | if (w->ww_ispty) { |
| 108 | if (p == w->ww_ob) { |
| 109 | w->ww_obp++; |
| 110 | w->ww_obq++; |
| 111 | } else |
| 112 | p--; |
| 113 | c = *p; |
| 114 | } |
| 115 | n = read(w->ww_pty, p, w->ww_obe - p); |
| 116 | if (n < 0) { |
| 117 | wwnwreade++; |
| 118 | (void) close(w->ww_pty); |
| 119 | w->ww_pty = -1; |
| 120 | } else if (n == 0) { |
| 121 | wwnwreadz++; |
| 122 | (void) close(w->ww_pty); |
| 123 | w->ww_pty = -1; |
| 124 | } else if (!w->ww_ispty) { |
| 125 | wwnwreadd++; |
| 126 | wwnwreadc += n; |
| 127 | w->ww_obq += n; |
| 128 | } else if (*p == TIOCPKT_DATA) { |
| 129 | n--; |
| 130 | wwnwreadd++; |
| 131 | wwnwreadc += n; |
| 132 | w->ww_obq += n; |
| 133 | } else { |
| 134 | wwnwreadp++; |
| 135 | if (*p & TIOCPKT_STOP) |
| 136 | w->ww_stopped = 1; |
| 137 | if (*p & TIOCPKT_START) |
| 138 | w->ww_stopped = 0; |
| 139 | if (*p & TIOCPKT_FLUSHWRITE) { |
| 140 | w->ww_stopped = 0; |
| 141 | w->ww_obq = w->ww_obp = |
| 142 | w->ww_ob; |
| 143 | } |
| 144 | } |
| 145 | if (w->ww_ispty) |
| 146 | *p = c; |
| 147 | } |
| 148 | for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) |
| 149 | if (w->ww_pty >= 0 && w->ww_obq > w->ww_obp && |
| 150 | !w->ww_stopped) { |
| 151 | n = wwwrite(w, w->ww_obp, |
| 152 | w->ww_obq - w->ww_obp); |
| 153 | if ((w->ww_obp += n) == w->ww_obq) |
| 154 | w->ww_obq = w->ww_obp = w->ww_ob; |
| 155 | if (wwinterrupt()) { |
| 156 | wwclrintr(); |
| 157 | return; |
| 158 | } |
| 159 | break; |
| 160 | } |
| 161 | } |
| 162 | } |