1 /* $OpenBSD: imsgev.c,v 1.13 2024/11/21 13:39:07 claudio Exp $ */
2
3 /*
4 * Copyright (c) 2009 Eric Faurot <eric@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include <sys/queue.h>
20 #include <sys/socket.h>
21 #include <sys/uio.h>
22
23 #include <errno.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <unistd.h>
28
29 #include "imsgev.h"
30 #include "log.h"
31
32 void imsgev_add(struct imsgev *);
33 void imsgev_dispatch(int, short, void *);
34 void imsgev_disconnect(struct imsgev *, int);
35
36 void
imsgev_init(struct imsgev * iev,int fd,void * data,void (* callback)(struct imsgev *,int,struct imsg *),void (* needfd)(struct imsgev *))37 imsgev_init(struct imsgev *iev, int fd, void *data,
38 void (*callback)(struct imsgev *, int, struct imsg *),
39 void (*needfd)(struct imsgev *))
40 {
41 if (imsgbuf_init(&iev->ibuf, fd) == -1)
42 fatal("imsgbuf_init");
43 imsgbuf_allow_fdpass(&iev->ibuf);
44 iev->terminate = 0;
45
46 iev->data = data;
47 iev->handler = imsgev_dispatch;
48 iev->callback = callback;
49 iev->needfd = needfd;
50
51 iev->events = EV_READ;
52 event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev);
53 event_add(&iev->ev, NULL);
54 }
55
56 int
imsgev_compose(struct imsgev * iev,u_int16_t type,u_int32_t peerid,uint32_t pid,int fd,void * data,u_int16_t datalen)57 imsgev_compose(struct imsgev *iev, u_int16_t type, u_int32_t peerid,
58 uint32_t pid, int fd, void *data, u_int16_t datalen)
59 {
60 int r;
61
62 r = imsg_compose(&iev->ibuf, type, peerid, pid, fd, data, datalen);
63 if (r != -1)
64 imsgev_add(iev);
65
66 return (r);
67 }
68
69 void
imsgev_close(struct imsgev * iev)70 imsgev_close(struct imsgev *iev)
71 {
72 iev->terminate = 1;
73 imsgev_add(iev);
74 }
75
76 void
imsgev_clear(struct imsgev * iev)77 imsgev_clear(struct imsgev *iev)
78 {
79 event_del(&iev->ev);
80 imsgbuf_clear(&iev->ibuf);
81 close(iev->ibuf.fd);
82 }
83
84 void
imsgev_add(struct imsgev * iev)85 imsgev_add(struct imsgev *iev)
86 {
87 short events = 0;
88
89 if (!iev->terminate)
90 events = EV_READ;
91 if (imsgbuf_queuelen(&iev->ibuf) > 0 || iev->terminate)
92 events |= EV_WRITE;
93
94 /* optimization: skip event_{del/set/add} if already set */
95 if (events == iev->events)
96 return;
97
98 iev->events = events;
99 event_del(&iev->ev);
100 event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev);
101 event_add(&iev->ev, NULL);
102 }
103
104 void
imsgev_dispatch(int fd,short ev,void * humppa)105 imsgev_dispatch(int fd, short ev, void *humppa)
106 {
107 struct imsgev *iev = humppa;
108 struct imsgbuf *ibuf = &iev->ibuf;
109 struct imsg imsg;
110 ssize_t n;
111
112 iev->events = 0;
113
114 if (ev & EV_READ) {
115 /* if we don't have enough fds, free one up and retry */
116 if (getdtablesize() <= getdtablecount() +
117 (int)((CMSG_SPACE(sizeof(int))-CMSG_SPACE(0))/sizeof(int)))
118 iev->needfd(iev);
119
120 if ((n = imsgbuf_read(ibuf)) == -1) {
121 imsgev_disconnect(iev, IMSGEV_EREAD);
122 return;
123 }
124 if (n == 0) {
125 /*
126 * Connection is closed for reading, and we assume
127 * it is also closed for writing, so we error out
128 * if write data is pending.
129 */
130 imsgev_disconnect(iev,
131 imsgbuf_queuelen(&iev->ibuf) > 0 ? IMSGEV_EWRITE :
132 IMSGEV_DONE);
133 return;
134 }
135 }
136
137 if (ev & EV_WRITE) {
138 /*
139 * We wanted to write data out but the connection is either
140 * closed, or some error occured. Both case are not recoverable
141 * from the imsg perspective, so we treat it as a WRITE error.
142 */
143 if (imsgbuf_write(ibuf) == -1) {
144 imsgev_disconnect(iev, IMSGEV_EWRITE);
145 return;
146 }
147 }
148
149 while (iev->terminate == 0) {
150 if ((n = imsg_get(ibuf, &imsg)) == -1) {
151 imsgev_disconnect(iev, IMSGEV_EIMSG);
152 return;
153 }
154 if (n == 0)
155 break;
156 iev->callback(iev, IMSGEV_IMSG, &imsg);
157 imsg_free(&imsg);
158 }
159
160 if (iev->terminate && imsgbuf_queuelen(&iev->ibuf) == 0) {
161 imsgev_disconnect(iev, IMSGEV_DONE);
162 return;
163 }
164
165 imsgev_add(iev);
166 }
167
168 void
imsgev_disconnect(struct imsgev * iev,int code)169 imsgev_disconnect(struct imsgev *iev, int code)
170 {
171 iev->callback(iev, code, NULL);
172 }
173