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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: chan.c,v 1.3 1999/07/27 18:30:53 mdw Exp $ |
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4 | * |
5 | * Channel management |
6 | * |
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7 | * (c) 1999 Straylight/Edgeware |
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8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the `fw' port forwarder. |
13 | * |
14 | * `fw' is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2 of the License, or |
17 | * (at your option) any later version. |
18 | * |
19 | * `fw' 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 General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU General Public License |
25 | * along with `fw'; if not, write to the Free Software Foundation, |
26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | */ |
28 | |
29 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: chan.c,v $ |
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32 | * Revision 1.3 1999/07/27 18:30:53 mdw |
33 | * Various minor portability fixes. |
34 | * |
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35 | * Revision 1.2 1999/07/26 23:27:52 mdw |
36 | * Minor modifications for new design. |
37 | * |
38 | * Revision 1.1.1.1 1999/07/01 08:56:23 mdw |
39 | * Initial revision. |
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40 | * |
41 | */ |
42 | |
43 | /*----- Header files ------------------------------------------------------*/ |
44 | |
45 | #include "config.h" |
46 | |
47 | #include <errno.h> |
48 | #include <stdio.h> |
49 | #include <stdlib.h> |
50 | #include <string.h> |
51 | |
52 | #include <sys/types.h> |
53 | #include <sys/time.h> |
54 | #include <unistd.h> |
55 | #include <sys/uio.h> |
56 | |
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57 | #include <mLib/alloc.h> |
58 | #include <mLib/conn.h> |
59 | #include <mLib/sel.h> |
60 | |
61 | #include "chan.h" |
62 | #include "fw.h" |
63 | |
64 | /*----- Main code ---------------------------------------------------------*/ |
65 | |
66 | /* --- @writechan@ --- * |
67 | * |
68 | * Arguments: @int fd@ = file descriptor to write to |
69 | * @unsigned mode@ = what the descriptor is ready for |
70 | * @void *vp@ = pointer to channel block |
71 | * |
72 | * Returns: --- |
73 | * |
74 | * Use: Writes to a channel. |
75 | */ |
76 | |
77 | static void writechan(int fd, unsigned mode, void *vp) |
78 | { |
79 | chan *c = vp; |
80 | int w; |
81 | unsigned base = c->base; |
82 | unsigned len = c->len; |
83 | |
84 | /* --- Write data from my buffer --- */ |
85 | |
86 | if (len) { |
87 | |
88 | /* --- Do the write --- */ |
89 | |
90 | if (base + len <= CHAN_BUFSZ) |
91 | w = write(fd, c->buf + base, len); |
92 | else { |
93 | struct iovec iov[2]; |
94 | iov[0].iov_base = c->buf + base; |
95 | iov[0].iov_len = CHAN_BUFSZ - base; |
96 | iov[1].iov_base = c->buf; |
97 | iov[1].iov_len = len - iov[0].iov_len; |
98 | w = writev(fd, iov, 2); |
99 | } |
100 | |
101 | /* --- Sift through the results --- */ |
102 | |
103 | if (w < 0) { |
104 | if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK) |
105 | return; |
106 | goto close; |
107 | } |
108 | else if (w == 0) |
109 | goto close; |
110 | else if (c->len == CHAN_BUFSZ && !(c->f & CHANF_CLOSE)) |
111 | sel_addfile(&c->r); |
112 | c->len -= w; |
113 | } |
114 | if (c->len == 0) |
115 | sel_rmfile(&c->w); |
116 | |
117 | /* --- Close the output end if necessary --- */ |
118 | |
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119 | if (c->len == 0 && (c->f & CHANF_CLOSE)) |
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120 | c->func(c->p); |
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121 | return; |
122 | |
123 | /* --- Force a close if an error occurred --- */ |
124 | |
125 | close: |
126 | chan_close(c); |
127 | c->func(c->p); |
128 | } |
129 | |
130 | /* --- @readchan@ --- * |
131 | * |
132 | * Arguments: @int fd@ = file descriptor to read from |
133 | * @unsigned mode@ = what the descriptor is ready for |
134 | * @void *vp@ = pointer to channel block |
135 | * |
136 | * Returns: --- |
137 | * |
138 | * Use: Reads from a channel. |
139 | */ |
140 | |
141 | static void readchan(int fd, unsigned mode, void *vp) |
142 | { |
143 | chan *c = vp; |
144 | int r; |
145 | unsigned base = (c->base + c->len) & (CHAN_BUFSZ - 1); |
146 | unsigned len = CHAN_BUFSZ - c->len; |
147 | |
148 | /* --- Do the read --- */ |
149 | |
150 | if (base + len <= CHAN_BUFSZ) |
151 | r = read(fd, c->buf + base, len); |
152 | else { |
153 | struct iovec iov[2]; |
154 | iov[0].iov_base = c->buf + base; |
155 | iov[0].iov_len = CHAN_BUFSZ - base; |
156 | iov[1].iov_base = c->buf; |
157 | iov[1].iov_len = len - iov[0].iov_len; |
158 | r = readv(fd, iov, 2); |
159 | } |
160 | |
161 | /* --- Sift through the results --- */ |
162 | |
163 | if (r < 0) { |
164 | if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK) |
165 | return; |
166 | goto close; |
167 | } |
168 | else if (r == 0) |
169 | goto close; |
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170 | else if (c->len == 0 && (c->f & CHANF_READY)) |
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171 | sel_addfile(&c->w); |
172 | c->len += r; |
173 | if (c->len == CHAN_BUFSZ) |
174 | sel_rmfile(&c->r); |
175 | return; |
176 | |
177 | /* --- Close the read end of the channel --- */ |
178 | |
179 | close: |
180 | c->f |= CHANF_CLOSE; |
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181 | if (!c->len && (c->f & CHANF_READY)) |
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182 | sel_addfile(&c->w); |
183 | sel_rmfile(&c->r); |
184 | } |
185 | |
186 | /* --- @chan_close@ --- * |
187 | * |
188 | * Arguments: @chan *c@ = pointer to channel |
189 | * |
190 | * Returns: --- |
191 | * |
192 | * Use: Closes down a channel prematurely. |
193 | */ |
194 | |
195 | void chan_close(chan *c) |
196 | { |
197 | if (!(c->f & CHANF_CLOSE) && c->len != CHAN_BUFSZ) |
198 | sel_rmfile(&c->r); |
199 | if ((c->f & CHANF_READY) && c->len != 0) |
200 | sel_rmfile(&c->w); |
201 | } |
202 | |
203 | /* --- @chan_dest@ --- * |
204 | * |
205 | * Arguments: @chan *c@ = pointer to channel |
206 | * @int fd@ = destination file descriptor for channel |
207 | * |
208 | * Returns: --- |
209 | * |
210 | * Use: Sets the channel's destination so it knows where to put |
211 | * data. |
212 | */ |
213 | |
214 | void chan_dest(chan *c, int fd) |
215 | { |
216 | if (c->f & CHANF_READY) |
217 | return; |
218 | sel_initfile(sel, &c->w, fd, SEL_WRITE, writechan, c); |
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219 | if (c->len || (c->f & CHANF_CLOSE)) |
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220 | sel_addfile(&c->w); |
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221 | c->f |= CHANF_READY; |
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222 | } |
223 | |
224 | /* --- @chan_open@ --- * |
225 | * |
226 | * Arguments: @chan *c@ = pointer to channel to open |
227 | * @int from, to@ = source and destination file descriptors |
228 | * @void (*func)(void *p)@ = function to call on closure |
229 | * @void *p@ = argument to pass to function |
230 | * |
231 | * Returns: --- |
232 | * |
233 | * Use: Opens a channel. Data is copied from the source to the |
234 | * destination. The @to@ argument may be @-1@ if the file |
235 | * descriptor isn't known yet. |
236 | */ |
237 | |
238 | void chan_open(chan *c, int from, int to, |
239 | void (*func)(void */*p*/), void *p) |
240 | { |
241 | c->func = func; |
242 | c->p = p; |
243 | |
244 | c->base = 0; |
245 | c->len = 0; |
246 | c->f = 0; |
247 | |
248 | sel_initfile(sel, &c->r, from, SEL_READ, readchan, c); |
249 | sel_addfile(&c->r); |
250 | |
251 | if (to != -1) |
252 | chan_dest(c, to); |
253 | } |
254 | |
255 | /*----- That's all, folks -------------------------------------------------*/ |