| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: sel.c,v 1.3 1999/05/21 22:13:59 mdw Exp $ |
| 4 | * |
| 5 | * I/O multiplexing support |
| 6 | * |
| 7 | * (c) 1999 Straylight/Edgeware |
| 8 | */ |
| 9 | |
| 10 | /*----- Licensing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of the mLib utilities library. |
| 13 | * |
| 14 | * mLib is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU Library General Public License as |
| 16 | * published by the Free Software Foundation; either version 2 of the |
| 17 | * License, or (at your option) any later version. |
| 18 | * |
| 19 | * mLib is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU Library General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU Library General Public |
| 25 | * License along with mLib; if not, write to the Free |
| 26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 27 | * MA 02111-1307, USA. |
| 28 | */ |
| 29 | |
| 30 | /*----- Revision history --------------------------------------------------* |
| 31 | * |
| 32 | * $Log: sel.c,v $ |
| 33 | * Revision 1.3 1999/05/21 22:13:59 mdw |
| 34 | * Use new `tv' macros. Fix ordering bug for timeout selectors. |
| 35 | * |
| 36 | * Revision 1.2 1999/05/15 10:33:32 mdw |
| 37 | * Fix copyright notices. |
| 38 | * |
| 39 | * Revision 1.1 1999/05/14 21:01:14 mdw |
| 40 | * Integrated `select' handling bits from the background resolver project. |
| 41 | * |
| 42 | */ |
| 43 | |
| 44 | /*----- Header files ------------------------------------------------------*/ |
| 45 | |
| 46 | #include <stdio.h> |
| 47 | #include <stdlib.h> |
| 48 | #include <string.h> |
| 49 | |
| 50 | #include <sys/types.h> |
| 51 | #include <sys/time.h> |
| 52 | #include <unistd.h> |
| 53 | |
| 54 | #include "sel.h" |
| 55 | #include "tv.h" |
| 56 | |
| 57 | /*----- Main code ---------------------------------------------------------*/ |
| 58 | |
| 59 | /* --- @sel_init@ --- * |
| 60 | * |
| 61 | * Arguments: @sel_state *s@ = pointer to a state block to initialize |
| 62 | * |
| 63 | * Returns: --- |
| 64 | * |
| 65 | * Use: Initializes a select state block. |
| 66 | */ |
| 67 | |
| 68 | void sel_init(sel_state *s) |
| 69 | { |
| 70 | s->files = 0; |
| 71 | s->timers = 0; |
| 72 | FD_ZERO(&s->fd[SEL_READ]); |
| 73 | FD_ZERO(&s->fd[SEL_WRITE]); |
| 74 | FD_ZERO(&s->fd[SEL_EXC]); |
| 75 | } |
| 76 | |
| 77 | /* --- @sel_initfile@ --- * |
| 78 | * |
| 79 | * Arguments: @sel_state *s@ = select state to attach to |
| 80 | * @sel_file *f@ = pointer to a file block to initialize |
| 81 | * @int fd@ = the file descriptor to listen to |
| 82 | * @unsigned mode@ = what to listen for |
| 83 | * @void (*func)(int fd, unsigned mode, void *p)@ = handler |
| 84 | * @void *p@ = argument to pass to handler |
| 85 | * |
| 86 | * Returns: --- |
| 87 | * |
| 88 | * Use: Initializes a file block ready for use. The file block |
| 89 | * isn't added to the list of things to do until a call to |
| 90 | * @sel_addfile@. |
| 91 | */ |
| 92 | |
| 93 | void sel_initfile(sel_state *s, sel_file *f, |
| 94 | int fd, unsigned mode, |
| 95 | void (*func)(int /*fd*/, unsigned /*mode*/, void */*p*/), |
| 96 | void *p) |
| 97 | { |
| 98 | f->s = s; |
| 99 | f->fd = fd; |
| 100 | f->mode = mode; |
| 101 | f->func = func; |
| 102 | f->p = p; |
| 103 | } |
| 104 | |
| 105 | /* --- @sel_addfile@ --- * |
| 106 | * |
| 107 | * Arguments: @sel_file *f@ = pointer to a file block |
| 108 | * |
| 109 | * Returns: --- |
| 110 | * |
| 111 | * Use: Adds a file block into the list of things to listen to. |
| 112 | */ |
| 113 | |
| 114 | void sel_addfile(sel_file *f) |
| 115 | { |
| 116 | sel_file **ff = &f->s->files; |
| 117 | |
| 118 | /* --- This little dance looks like line-noise, but it does the job --- */ |
| 119 | |
| 120 | while (*ff && (*ff)->fd > f->fd) |
| 121 | ff = &(*ff)->next; |
| 122 | f->next = *ff; |
| 123 | f->prev = (sel_file *)ff; |
| 124 | if (*ff) |
| 125 | (*ff)->prev = f; |
| 126 | *ff = f; |
| 127 | FD_SET(f->fd, f->s->fd + f->mode); |
| 128 | } |
| 129 | |
| 130 | /* --- @sel_rmfile@ --- * |
| 131 | * |
| 132 | * Arguments: @sel_file *f@ = pointer to a file block |
| 133 | * |
| 134 | * Returns: --- |
| 135 | * |
| 136 | * Use: Removes a file block from the list of things to listen to. |
| 137 | */ |
| 138 | |
| 139 | void sel_rmfile(sel_file *f) |
| 140 | { |
| 141 | f->prev->next = f->next; |
| 142 | if (f->next) |
| 143 | f->next->prev = f->prev; |
| 144 | FD_CLR(f->fd, f->s->fd + f->mode); |
| 145 | } |
| 146 | |
| 147 | /* --- @sel_addtimer@ --- * |
| 148 | * |
| 149 | * Arguments: @sel_state *s@ = pointer to a state block |
| 150 | * @sel_timer *t@ = pointer to a timer block |
| 151 | * @struct timeval *tv@ = pointer to time to activate |
| 152 | * @void (*func)(struct timeval *tv, void *p)@ = handler |
| 153 | * @void *p@ = argument for handler function |
| 154 | * |
| 155 | * Returns: --- |
| 156 | * |
| 157 | * Use: Registers and sets up a timer. |
| 158 | */ |
| 159 | |
| 160 | void sel_addtimer(sel_state *s, sel_timer *t, |
| 161 | struct timeval *tv, |
| 162 | void (*func)(struct timeval */*tv*/, void */*p*/), |
| 163 | void *p) |
| 164 | { |
| 165 | sel_timer **tt = &s->timers; |
| 166 | |
| 167 | /* --- Set up the timer block --- */ |
| 168 | |
| 169 | t->tv = *tv; |
| 170 | t->func = func; |
| 171 | t->p = p; |
| 172 | |
| 173 | /* --- More line noise --- */ |
| 174 | |
| 175 | while (*tt && TV_CMP(&(*tt)->tv, <, tv)) |
| 176 | tt = &(*tt)->next; |
| 177 | t->next = *tt; |
| 178 | t->prev = (sel_timer *)tt; |
| 179 | if (*tt) |
| 180 | (*tt)->prev = t; |
| 181 | *tt = t; |
| 182 | } |
| 183 | |
| 184 | /* --- @sel_rmtimer@ --- * |
| 185 | * |
| 186 | * Arguments: @sel_timer *t@ = pointer to timer block |
| 187 | * |
| 188 | * Returns: --- |
| 189 | * |
| 190 | * Use: Removes a timer from the list of timers. |
| 191 | */ |
| 192 | |
| 193 | void sel_rmtimer(sel_timer *t) |
| 194 | { |
| 195 | t->prev->next = t->next; |
| 196 | if (t->next) |
| 197 | t->next->prev = t->prev; |
| 198 | } |
| 199 | |
| 200 | /* --- @sel_select@ --- * |
| 201 | * |
| 202 | * Arguments: @sel_state *s@ = pointer to state block |
| 203 | * |
| 204 | * Returns: Zero if all OK, -1 on error. |
| 205 | * |
| 206 | * Use: Does a @select@ call (or equivalent @poll@). |
| 207 | */ |
| 208 | |
| 209 | int sel_select(sel_state *s) |
| 210 | { |
| 211 | fd_set fd[SEL_MODES]; |
| 212 | struct timeval tv; |
| 213 | int err; |
| 214 | |
| 215 | memcpy(fd, s->fd, sizeof(s->fd)); |
| 216 | if (s->timers) { |
| 217 | struct timeval now; |
| 218 | gettimeofday(&now, 0); |
| 219 | TV_SUB(&tv, &s->timers->tv, &now); |
| 220 | err = select(s->files ? s->files->fd + 1 : 0, |
| 221 | fd + SEL_READ, fd + SEL_WRITE, fd + SEL_EXC, |
| 222 | &tv); |
| 223 | gettimeofday(&tv, 0); |
| 224 | } else |
| 225 | err = select(s->files ? s->files->fd + 1 : 0, |
| 226 | fd + SEL_READ, fd + SEL_WRITE, fd + SEL_EXC, |
| 227 | 0); |
| 228 | |
| 229 | if (err < 0) |
| 230 | return (err); |
| 231 | |
| 232 | { |
| 233 | sel_timer *t, *tt; |
| 234 | for (t = s->timers; t && TV_CMP(&t->tv, <=, &tv); t = tt) { |
| 235 | tt = t->next; |
| 236 | t->next = t->prev = t; |
| 237 | t->func(&tv, t->p); |
| 238 | } |
| 239 | s->timers = t; |
| 240 | if (t) |
| 241 | t->prev = (sel_timer *)&s->timers; |
| 242 | } |
| 243 | |
| 244 | { |
| 245 | sel_file *f, *ff; |
| 246 | for (f = s->files; f; f = ff) { |
| 247 | ff = f->next; |
| 248 | if (FD_ISSET(f->fd, fd + f->mode)) |
| 249 | f->func(f->fd, f->mode, f->p); |
| 250 | } |
| 251 | } |
| 252 | |
| 253 | return (0); |
| 254 | } |
| 255 | |
| 256 | /*----- That's all, folks -------------------------------------------------*/ |