1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /*
27 * File Descriptor I/O Backend
28 *
29 * Simple backend to pass though io_ops to the corresponding system calls on
30 * an underlying fd. We provide functions to create fdio objects using file
31 * descriptors, explicit file names, and path lookups. We save the complete
32 * filename so that mdb_iob_name can be used to report the complete filename
33 * of an open macro file in syntax error messages.
34 */
35
36 #include <sys/param.h>
37 #include <sys/stat.h>
38 #include <sys/dkio.h>
39 #include <unistd.h>
40 #include <string.h>
41 #include <errno.h>
42 #include <fcntl.h>
43
44 #include <mdb/mdb_modapi.h>
45 #include <mdb/mdb_err.h>
46 #include <mdb/mdb_io_impl.h>
47 #include <mdb/mdb.h>
48
49 typedef struct fd_data {
50 char fd_name[MAXPATHLEN]; /* Save filename for error messages */
51 int fd_fd; /* File descriptor */
52 } fd_data_t;
53
54 static ssize_t
fdio_read(mdb_io_t * io,void * buf,size_t nbytes)55 fdio_read(mdb_io_t *io, void *buf, size_t nbytes)
56 {
57 fd_data_t *fdp = io->io_data;
58
59 if (io->io_next == NULL)
60 return (read(fdp->fd_fd, buf, nbytes));
61
62 return (IOP_READ(io->io_next, buf, nbytes));
63 }
64
65 static ssize_t
fdio_write(mdb_io_t * io,const void * buf,size_t nbytes)66 fdio_write(mdb_io_t *io, const void *buf, size_t nbytes)
67 {
68 fd_data_t *fdp = io->io_data;
69
70 if (io->io_next == NULL)
71 return (write(fdp->fd_fd, buf, nbytes));
72
73 return (IOP_WRITE(io->io_next, buf, nbytes));
74 }
75
76 static off64_t
fdio_seek(mdb_io_t * io,off64_t offset,int whence)77 fdio_seek(mdb_io_t *io, off64_t offset, int whence)
78 {
79 fd_data_t *fdp = io->io_data;
80
81 if (io->io_next == NULL)
82 return (lseek64(fdp->fd_fd, offset, whence));
83
84 return (IOP_SEEK(io->io_next, offset, whence));
85 }
86
87 static int
fdio_ctl(mdb_io_t * io,int req,void * arg)88 fdio_ctl(mdb_io_t *io, int req, void *arg)
89 {
90 fd_data_t *fdp = io->io_data;
91
92 if (io->io_next != NULL)
93 return (IOP_CTL(io->io_next, req, arg));
94
95 if (req == MDB_IOC_GETFD)
96 return (fdp->fd_fd);
97 else
98 return (ioctl(fdp->fd_fd, req, arg));
99 }
100
101 static void
fdio_close(mdb_io_t * io)102 fdio_close(mdb_io_t *io)
103 {
104 fd_data_t *fdp = io->io_data;
105
106 (void) close(fdp->fd_fd);
107 mdb_free(fdp, sizeof (fd_data_t));
108 }
109
110 static const char *
fdio_name(mdb_io_t * io)111 fdio_name(mdb_io_t *io)
112 {
113 fd_data_t *fdp = io->io_data;
114
115 if (io->io_next == NULL)
116 return (fdp->fd_name);
117
118 return (IOP_NAME(io->io_next));
119 }
120
121 mdb_io_t *
mdb_fdio_create_path(const char * path[],const char * fname,int flags,mode_t mode)122 mdb_fdio_create_path(const char *path[], const char *fname,
123 int flags, mode_t mode)
124 {
125 int fd;
126 char buf[MAXPATHLEN];
127
128 if (path != NULL && strchr(fname, '/') == NULL) {
129 int i;
130
131 for (fd = -1, i = 0; path[i] != NULL; i++) {
132 (void) mdb_iob_snprintf(buf, MAXPATHLEN, "%s/%s",
133 path[i], fname);
134
135 if (access(buf, F_OK) == 0) {
136 fd = open64(buf, flags, mode);
137 fname = buf;
138 break;
139 }
140 }
141
142 if (fd == -1)
143 (void) set_errno(ENOENT);
144 } else
145 fd = open64(fname, flags, mode);
146
147 if (fd >= 0)
148 return (mdb_fdio_create_named(fd, fname));
149
150 return (NULL);
151 }
152
153 static const mdb_io_ops_t fdio_file_ops = {
154 .io_read = fdio_read,
155 .io_write = fdio_write,
156 .io_seek = fdio_seek,
157 .io_ctl = fdio_ctl,
158 .io_close = fdio_close,
159 .io_name = fdio_name,
160 .io_link = no_io_link,
161 .io_unlink = no_io_unlink,
162 .io_setattr = no_io_setattr,
163 .io_suspend = no_io_suspend,
164 .io_resume = no_io_resume
165 };
166
167 /*
168 * Read media logical block size. On error, return DEV_BSIZE.
169 */
170 static uint_t
fdio_bdev_info(int fd)171 fdio_bdev_info(int fd)
172 {
173 struct dk_minfo disk_info;
174
175 if ((ioctl(fd, DKIOCGMEDIAINFO, (caddr_t)&disk_info)) == -1)
176 return (DEV_BSIZE);
177
178 return (disk_info.dki_lbsize);
179 }
180
181 /*
182 * In order to read from a block-oriented device, we pick up the seek pointer,
183 * read each containing block, and then copy the desired range of bytes back
184 * into the caller's buffer. At the end of the transfer we reset the seek
185 * pointer to where the caller thinks it should be.
186 */
187 static ssize_t
fdio_bdev_read(mdb_io_t * io,void * buf,size_t nbytes)188 fdio_bdev_read(mdb_io_t *io, void *buf, size_t nbytes)
189 {
190 fd_data_t *fdp = io->io_data;
191 ssize_t resid = nbytes;
192 size_t blksize;
193 uchar_t *blk;
194 off64_t off;
195
196 if (io->io_next != NULL)
197 return (IOP_READ(io->io_next, buf, nbytes));
198
199 if ((off = lseek64(fdp->fd_fd, 0, SEEK_CUR)) == -1)
200 return (-1); /* errno is set for us */
201
202 blksize = fdio_bdev_info(fdp->fd_fd);
203 blk = mdb_zalloc(blksize, UM_SLEEP | UM_GC);
204 while (resid != 0) {
205 off64_t devoff = off & ~(blksize - 1);
206 size_t blkoff = off & (blksize - 1);
207 size_t len = MIN(resid, blksize - blkoff);
208
209 if (pread64(fdp->fd_fd, blk, blksize, devoff) != blksize)
210 break; /* errno is set for us, unless EOF */
211
212 bcopy(&blk[blkoff], buf, len);
213 resid -= len;
214 off += len;
215 buf = (char *)buf + len;
216 }
217
218 if (resid == nbytes && nbytes != 0)
219 return (set_errno(EMDB_EOF));
220
221 (void) lseek64(fdp->fd_fd, off, SEEK_SET);
222 return (nbytes - resid);
223 }
224
225 /*
226 * To perform a write to a block-oriented device, we use the same basic
227 * algorithm as fdio_bdev_read(), above. In the inner loop, we read an
228 * entire block, modify it using the data from the caller's buffer, and
229 * then write the entire block back to the device.
230 */
231 static ssize_t
fdio_bdev_write(mdb_io_t * io,const void * buf,size_t nbytes)232 fdio_bdev_write(mdb_io_t *io, const void *buf, size_t nbytes)
233 {
234 fd_data_t *fdp = io->io_data;
235 ssize_t resid = nbytes;
236 size_t blksize;
237 uchar_t *blk;
238 off64_t off;
239
240 if (io->io_next != NULL)
241 return (IOP_WRITE(io->io_next, buf, nbytes));
242
243 if ((off = lseek64(fdp->fd_fd, 0, SEEK_CUR)) == -1)
244 return (-1); /* errno is set for us */
245
246 blksize = fdio_bdev_info(fdp->fd_fd);
247 blk = mdb_zalloc(blksize, UM_SLEEP | UM_GC);
248 while (resid != 0) {
249 off64_t devoff = off & ~(blksize - 1);
250 size_t blkoff = off & (blksize - 1);
251 size_t len = MIN(resid, blksize - blkoff);
252
253 if (pread64(fdp->fd_fd, blk, blksize, devoff) != blksize)
254 break; /* errno is set for us, unless EOF */
255
256 bcopy(buf, &blk[blkoff], len);
257
258 if (pwrite64(fdp->fd_fd, blk, blksize, devoff) != blksize)
259 break; /* errno is set for us, unless EOF */
260
261 resid -= len;
262 off += len;
263 buf = (char *)buf + len;
264 }
265
266 if (resid == nbytes && nbytes != 0)
267 return (set_errno(EMDB_EOF));
268
269 (void) lseek64(fdp->fd_fd, off, SEEK_SET);
270 return (nbytes - resid);
271 }
272
273 static const mdb_io_ops_t fdio_bdev_ops = {
274 .io_read = fdio_bdev_read,
275 .io_write = fdio_bdev_write,
276 .io_seek = fdio_seek,
277 .io_ctl = fdio_ctl,
278 .io_close = fdio_close,
279 .io_name = fdio_name,
280 .io_link = no_io_link,
281 .io_unlink = no_io_unlink,
282 .io_setattr = no_io_setattr,
283 .io_suspend = no_io_suspend,
284 .io_resume = no_io_resume,
285 };
286
287 mdb_io_t *
mdb_fdio_create(int fd)288 mdb_fdio_create(int fd)
289 {
290 mdb_io_t *io = mdb_alloc(sizeof (mdb_io_t), UM_SLEEP);
291 fd_data_t *fdp = mdb_alloc(sizeof (fd_data_t), UM_SLEEP);
292
293 struct dk_cinfo info;
294 struct stat64 st;
295
296 switch (fd) {
297 case STDIN_FILENO:
298 (void) strcpy(fdp->fd_name, "(stdin)");
299 break;
300 case STDOUT_FILENO:
301 (void) strcpy(fdp->fd_name, "(stdout)");
302 break;
303 case STDERR_FILENO:
304 (void) strcpy(fdp->fd_name, "(stderr)");
305 break;
306 default:
307 (void) mdb_iob_snprintf(fdp->fd_name, MAXPATHLEN, "fd %d", fd);
308 }
309
310 fdp->fd_fd = fd;
311
312 /*
313 * We determine if something is a raw block-oriented disk device by
314 * testing to see if it is a character device that supports DKIOCINFO.
315 * If we are operating on a disk in raw mode, we must do our own
316 * block-oriented i/o; otherwise we can just use read() and write().
317 */
318 if (fstat64(fd, &st) == 0 && S_ISCHR(st.st_mode) &&
319 ioctl(fd, DKIOCINFO, &info) == 0)
320 io->io_ops = &fdio_bdev_ops;
321 else
322 io->io_ops = &fdio_file_ops;
323
324 io->io_data = fdp;
325 io->io_next = NULL;
326 io->io_refcnt = 0;
327
328 return (io);
329 }
330
331 mdb_io_t *
mdb_fdio_create_named(int fd,const char * name)332 mdb_fdio_create_named(int fd, const char *name)
333 {
334 mdb_io_t *io = mdb_fdio_create(fd);
335 fd_data_t *fdp = io->io_data;
336
337 (void) strncpy(fdp->fd_name, name, MAXPATHLEN);
338 fdp->fd_name[MAXPATHLEN - 1] = '\0';
339
340 return (io);
341 }
342
343 int
mdb_fdio_fileno(mdb_io_t * io)344 mdb_fdio_fileno(mdb_io_t *io)
345 {
346 fd_data_t *fdp = io->io_data;
347 return (fdp->fd_fd);
348 }
349