1 /* $NetBSD: shmif_user.c,v 1.1 2014/03/13 01:42:59 pooka Exp $ */
2
3 /*-
4 * Copyright (c) 2009, 2010 Antti Kantee. All Rights Reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27 #ifndef _KERNEL
28 #include <sys/types.h>
29 #include <sys/mman.h>
30
31 #include <errno.h>
32
33 #include <rump/rumpuser_component.h>
34
35 #include "shmif_user.h"
36
37 #define seterr(_v_) if ((_v_) == -1) *error = errno; else *error = 0;
38
39 /*
40 * On BSD we use kqueue, on Linux we use inotify. The underlying
41 * interface requirements aren't quite the same, but we have a very
42 * good chance of doing the fd->path mapping on Linux thanks to dcache,
43 * so just keep the existing interfaces for now.
44 */
45 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__) \
46 || defined(__OpenBSD__)
47 #include <sys/event.h>
48
49 #include <stdlib.h>
50
51 #include <unistd.h>
52
53 int
rumpcomp_shmif_watchsetup(int * kqp,int fd)54 rumpcomp_shmif_watchsetup(int *kqp, int fd)
55 {
56 struct kevent kev;
57 int rv, kq;
58
59 kq = *kqp;
60 if (kq == -1) {
61 kq = kqueue();
62 if (kq == -1) {
63 rv = errno;
64 goto out;
65 }
66 }
67
68 EV_SET(&kev, fd, EVFILT_VNODE, EV_ADD|EV_ENABLE|EV_CLEAR,
69 NOTE_WRITE, 0, 0);
70 if (kevent(kq, &kev, 1, NULL, 0, NULL) == -1) {
71 rv = errno;
72 } else {
73 rv = 0;
74 *kqp = kq;
75 }
76
77 out:
78 return rumpuser_component_errtrans(rv);
79 }
80
81 int
rumpcomp_shmif_watchwait(int kq)82 rumpcomp_shmif_watchwait(int kq)
83 {
84 void *cookie;
85 struct kevent kev;
86 int rv;
87
88 cookie = rumpuser_component_unschedule();
89 do {
90 rv = kevent(kq, NULL, 0, &kev, 1, NULL);
91 } while (rv == -1 && errno == EINTR);
92 if (rv == -1) {
93 rv = errno;
94 } else {
95 rv = 0;
96 }
97 rumpuser_component_schedule(cookie);
98
99 return rumpuser_component_errtrans(rv);
100 }
101
102 #elif defined(__linux__)
103 #include <sys/inotify.h>
104
105 #include <limits.h>
106 #include <stdio.h>
107
108 int
rumpcomp_shmif_watchsetup(int * inotifyp,int fd)109 rumpcomp_shmif_watchsetup(int *inotifyp, int fd)
110 {
111 char procbuf[PATH_MAX], linkbuf[PATH_MAX];
112 ssize_t nn;
113 int inotify, rv;
114
115 inotify = *inotifyp;
116 if (inotify == -1) {
117 inotify = inotify_init();
118 if (inotify == -1) {
119 rv = errno;
120 goto out;
121 }
122 }
123
124 /* ok, need to map fd into path for inotify */
125 snprintf(procbuf, sizeof(procbuf), "/proc/self/fd/%d", fd);
126 nn = readlink(procbuf, linkbuf, sizeof(linkbuf)-1);
127 if (nn >= (ssize_t)sizeof(linkbuf)-1) {
128 nn = -1;
129 errno = E2BIG; /* pick something */
130 }
131 if (nn == -1) {
132 rv = errno;
133 close(inotify);
134 goto out;
135 }
136
137 linkbuf[nn] = '\0';
138 if (inotify_add_watch(inotify, linkbuf, IN_MODIFY) == -1) {
139 rv = errno;
140 close(inotify);
141 goto out;
142 }
143 rv = 0;
144 *inotifyp = inotify;
145
146 out:
147 return rumpuser_component_errtrans(rv);
148 }
149
150 int
rumpcomp_shmif_watchwait(int kq)151 rumpcomp_shmif_watchwait(int kq)
152 {
153 struct inotify_event iev;
154 void *cookie;
155 ssize_t nn;
156 int rv;
157
158 cookie = rumpuser_component_unschedule();
159 do {
160 nn = read(kq, &iev, sizeof(iev));
161 } while (nn == -1 && errno == EINTR);
162 if (nn == -1) {
163 rv = errno;
164 } else {
165 rv = 0;
166 }
167
168 rumpuser_component_schedule(cookie);
169
170 return rumpuser_component_errtrans(rv);
171 }
172
173 #else
174 #include <stdio.h>
175
176 /* a polling default implementation */
177 int
rumpcomp_shmif_watchsetup(int * nono,int fd)178 rumpcomp_shmif_watchsetup(int *nono, int fd)
179 {
180 static int warned = 0;
181
182 if (!warned) {
183 fprintf(stderr, "WARNING: rumpuser writewatchfile routines are "
184 "polling-only on this platform\n");
185 warned = 1;
186 }
187
188 return 0;
189 }
190
191 int
rumpcomp_shmif_watchwait(int kq)192 rumpcomp_shmif_watchwait(int kq)
193 {
194 void *cookie;
195
196 cookie = rumpuser_component_unschedule();
197 usleep(10000);
198 rumpuser_component_schedule(cookie);
199
200 return 0;
201 }
202 #endif
203
204 int
rumpcomp_shmif_mmap(int fd,size_t len,void ** memp)205 rumpcomp_shmif_mmap(int fd, size_t len, void **memp)
206 {
207 void *mem;
208 int rv;
209
210 if (ftruncate(fd, len) == -1) {
211 rv = errno;
212 goto out;
213 }
214
215 #if defined(__sun__) && !defined(MAP_FILE)
216 #define MAP_FILE 0
217 #endif
218
219 mem = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_FILE|MAP_SHARED, fd, 0);
220 if (mem == MAP_FAILED) {
221 rv = errno;
222 } else {
223 rv = 0;
224 *memp = mem;
225 }
226
227 out:
228 return rumpuser_component_errtrans(rv);
229 }
230 #endif
231