quorum: Avoid bdrv_aio_writev() for rewrites
[qemu.git] / io / channel-file.c
1 /*
2 * QEMU I/O channels files driver
3 *
4 * Copyright (c) 2015 Red Hat, Inc.
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18 *
19 */
20
21 #include "qemu/osdep.h"
22 #include "io/channel-file.h"
23 #include "io/channel-watch.h"
24 #include "qapi/error.h"
25 #include "qemu/sockets.h"
26 #include "trace.h"
27
28 QIOChannelFile *
29 qio_channel_file_new_fd(int fd)
30 {
31 QIOChannelFile *ioc;
32
33 ioc = QIO_CHANNEL_FILE(object_new(TYPE_QIO_CHANNEL_FILE));
34
35 ioc->fd = fd;
36
37 trace_qio_channel_file_new_fd(ioc, fd);
38
39 return ioc;
40 }
41
42
43 QIOChannelFile *
44 qio_channel_file_new_path(const char *path,
45 int flags,
46 mode_t mode,
47 Error **errp)
48 {
49 QIOChannelFile *ioc;
50
51 ioc = QIO_CHANNEL_FILE(object_new(TYPE_QIO_CHANNEL_FILE));
52
53 if (flags & O_WRONLY) {
54 ioc->fd = open(path, flags, mode);
55 } else {
56 ioc->fd = open(path, flags);
57 }
58 if (ioc->fd < 0) {
59 object_unref(OBJECT(ioc));
60 error_setg_errno(errp, errno,
61 "Unable to open %s", path);
62 return NULL;
63 }
64
65 trace_qio_channel_file_new_path(ioc, path, flags, mode, ioc->fd);
66
67 return ioc;
68 }
69
70
71 static void qio_channel_file_init(Object *obj)
72 {
73 QIOChannelFile *ioc = QIO_CHANNEL_FILE(obj);
74 ioc->fd = -1;
75 }
76
77 static void qio_channel_file_finalize(Object *obj)
78 {
79 QIOChannelFile *ioc = QIO_CHANNEL_FILE(obj);
80 if (ioc->fd != -1) {
81 close(ioc->fd);
82 ioc->fd = -1;
83 }
84 }
85
86
87 static ssize_t qio_channel_file_readv(QIOChannel *ioc,
88 const struct iovec *iov,
89 size_t niov,
90 int **fds,
91 size_t *nfds,
92 Error **errp)
93 {
94 QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
95 ssize_t ret;
96
97 retry:
98 ret = readv(fioc->fd, iov, niov);
99 if (ret < 0) {
100 if (errno == EAGAIN) {
101 return QIO_CHANNEL_ERR_BLOCK;
102 }
103 if (errno == EINTR) {
104 goto retry;
105 }
106
107 error_setg_errno(errp, errno,
108 "Unable to read from file");
109 return -1;
110 }
111
112 return ret;
113 }
114
115 static ssize_t qio_channel_file_writev(QIOChannel *ioc,
116 const struct iovec *iov,
117 size_t niov,
118 int *fds,
119 size_t nfds,
120 Error **errp)
121 {
122 QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
123 ssize_t ret;
124
125 retry:
126 ret = writev(fioc->fd, iov, niov);
127 if (ret <= 0) {
128 if (errno == EAGAIN) {
129 return QIO_CHANNEL_ERR_BLOCK;
130 }
131 if (errno == EINTR) {
132 goto retry;
133 }
134 error_setg_errno(errp, errno,
135 "Unable to write to file");
136 return -1;
137 }
138 return ret;
139 }
140
141 static int qio_channel_file_set_blocking(QIOChannel *ioc,
142 bool enabled,
143 Error **errp)
144 {
145 QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
146
147 if (enabled) {
148 qemu_set_block(fioc->fd);
149 } else {
150 qemu_set_nonblock(fioc->fd);
151 }
152 return 0;
153 }
154
155
156 static off_t qio_channel_file_seek(QIOChannel *ioc,
157 off_t offset,
158 int whence,
159 Error **errp)
160 {
161 QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
162 off_t ret;
163
164 ret = lseek(fioc->fd, offset, whence);
165 if (ret == (off_t)-1) {
166 error_setg_errno(errp, errno,
167 "Unable to seek to offset %lld whence %d in file",
168 (long long int)offset, whence);
169 return -1;
170 }
171 return ret;
172 }
173
174
175 static int qio_channel_file_close(QIOChannel *ioc,
176 Error **errp)
177 {
178 QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
179
180 if (close(fioc->fd) < 0) {
181 error_setg_errno(errp, errno,
182 "Unable to close file");
183 return -1;
184 }
185 return 0;
186 }
187
188
189 static GSource *qio_channel_file_create_watch(QIOChannel *ioc,
190 GIOCondition condition)
191 {
192 QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
193 return qio_channel_create_fd_watch(ioc,
194 fioc->fd,
195 condition);
196 }
197
198 static void qio_channel_file_class_init(ObjectClass *klass,
199 void *class_data G_GNUC_UNUSED)
200 {
201 QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
202
203 ioc_klass->io_writev = qio_channel_file_writev;
204 ioc_klass->io_readv = qio_channel_file_readv;
205 ioc_klass->io_set_blocking = qio_channel_file_set_blocking;
206 ioc_klass->io_seek = qio_channel_file_seek;
207 ioc_klass->io_close = qio_channel_file_close;
208 ioc_klass->io_create_watch = qio_channel_file_create_watch;
209 }
210
211 static const TypeInfo qio_channel_file_info = {
212 .parent = TYPE_QIO_CHANNEL,
213 .name = TYPE_QIO_CHANNEL_FILE,
214 .instance_size = sizeof(QIOChannelFile),
215 .instance_init = qio_channel_file_init,
216 .instance_finalize = qio_channel_file_finalize,
217 .class_init = qio_channel_file_class_init,
218 };
219
220 static void qio_channel_file_register_types(void)
221 {
222 type_register_static(&qio_channel_file_info);
223 }
224
225 type_init(qio_channel_file_register_types);