mdw@git.distorted.org.uk Git - mLib/blob - selpk.c

   1 /* -*-c-*-
   2  *
   3  * $Id: selpk.c,v 1.1 2000/06/17 10:39:19 mdw Exp $
   4  *
   5  * Packet-buffering select handler
   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: selpk.c,v $
  33  * Revision 1.1  2000/06/17 10:39:19  mdw
  34  * Experimental new support for packet buffering.
  35  *
  36  */
  37
  38 /*----- Header files ------------------------------------------------------*/
  39
  40 #include <errno.h>
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44
  45 #include <sys/types.h>
  46 #include <sys/time.h>
  47 #include <unistd.h>
  48
  49 #include "pkbuf.h"
  50 #include "sel.h"
  51 #include "selpk.h"
  52
  53 /*----- Main code ---------------------------------------------------------*/
  54
  55 /* --- @selpk_enable@ --- *
  56  *
  57  * Arguments:   @selpk *pk@ = pointer to buffer block
  58  *
  59  * Returns:     ---
  60  *
  61  * Use:         Enables a buffer for reading, and emits any queued packets
  62  *              to the buffer's owner.
  63  */
  64
  65 void selpk_enable(selpk *pk)
  66 {
  67   if (!(pk->pk.f & PKBUF_ENABLE)) {
  68     pk->pk.f |= PKBUF_ENABLE;
  69     sel_addfile(&pk->reader);
  70     pkbuf_flush(&pk->pk, 0, 0);
  71   }
  72 }
  73
  74 /* --- @selpk_disable@ --- *
  75  *
  76  * Arguments:   @selpk *pk@ = pointer to a buffer block
  77  *
  78  * Returns:     ---
  79  *
  80  * Use:         Disables a buffer.  It won't be read from until it's
  81  *              enabled again.
  82  */
  83
  84 void selpk_disable(selpk *pk)
  85 {
  86   if (pk->pk.f & PKBUF_ENABLE) {
  87     pk->pk.f &= ~PKBUF_ENABLE;
  88     sel_rmfile(&pk->reader);
  89   }
  90 }
  91
  92 /* --- @selpk_read@ --- *
  93  *
  94  * Arguments:   @int fd@ = file descriptor to read from
  95  *              @int mode@ = what we can do to the file
  96  *              @void *vp@ = pointer to buffer context
  97  *
  98  * Returns:     ---
  99  *
 100  * Use:         Acts on the result of a @select@ call.
 101  */
 102
 103 static void selpk_read(int fd, unsigned mode, void *vp)
 104 {
 105   selpk *pk = vp;
 106   octet *p;
 107   size_t sz;
 108   int n;
 109
 110   sz = pkbuf_free(&pk->pk, &p);
 111   n = read(fd, p, sz);
 112   if (n == 0)
 113     pkbuf_close(&pk->pk);
 114   else if (n > 0)
 115     pkbuf_flush(&pk->pk, p, n);
 116   else switch (errno) {
 117     case EINTR:
 118     case EAGAIN:
 119 #if EAGAIN != EWOULDBLOCK
 120     case EWOULDBLOCK:
 121 #endif
 122       return;
 123     default:
 124       pkbuf_close(&pk->pk);
 125   }
 126 }
 127
 128 /* --- @selpk_want@ --- *
 129  *
 130  * Arguments:   @selpk *pk@ = pointer to buffer block
 131  *              @size_t sz@ = size of buffer
 132  *
 133  * Returns:     ---
 134  *
 135  * Use:         Sets the size of the packet to be read next.
 136  */
 137
 138 void selpk_want(selpk *pk, size_t sz)
 139 {
 140   pkbuf_want(&pk->pk, sz);
 141 }
 142
 143 /* --- @selpk_init@ --- *
 144  *
 145  * Arguments:   @selpk *pk@ = pointer to buffer block
 146  *              @sel_state *s@ = pointer to select state to attach to
 147  *              @int fd@ = file descriptor to listen to
 148  *              @void (*func)(char *s, void *p)@ = function to call
 149  *              @void *p@ = argument for function
 150  *
 151  * Returns:     ---
 152  *
 153  * Use:         Initializes a buffer block.
 154  */
 155
 156 void selpk_init(selpk *pk,
 157                  sel_state *s,
 158                  int fd,
 159                  void (*func)(octet */*b*/, size_t /*sz*/, pkbuf */*pk*/,
 160                               size_t */*keep*/, void */*p*/),
 161                  void *p)
 162 {
 163   pkbuf_init(&pk->pk, func, p);
 164   pk->pk.f &= ~PKBUF_ENABLE;
 165   sel_initfile(s, &pk->reader, fd, SEL_READ, selpk_read, pk);
 166   selpk_enable(pk);
 167 }
 168
 169 /* --- @selpk_destroy@ --- *
 170  *
 171  * Arguments:   @selpk *pk@ = pointer to buffer block
 172  *
 173  * Returns:     ---
 174  *
 175  * Use:         Deallocates a packet buffer and frees any resources it owned.
 176  */
 177
 178 void selpk_destroy(selpk *pk)
 179 {
 180   selpk_disable(pk);
 181   pkbuf_destroy(&pk->pk);
 182 }
 183
 184 /*----- That's all, folks -------------------------------------------------*/