xref: /aosp_15_r20/external/mtools/plain_io.c (revision d5c9a868b113e0ec0db2f27bc2ce8a253e77c4b0)
1 /*  Copyright 1995-2007,2009,2011 Alain Knaff.
2  *  This file is part of mtools.
3  *
4  *  Mtools is free software: you can redistribute it and/or modify
5  *  it under the terms of the GNU General Public License as published by
6  *  the Free Software Foundation, either version 3 of the License, or
7  *  (at your option) any later version.
8  *
9  *  Mtools is distributed in the hope that it will be useful,
10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  *  GNU General Public License for more details.
13  *
14  *  You should have received a copy of the GNU General Public License
15  *  along with Mtools.  If not, see <http://www.gnu.org/licenses/>.
16  *
17  * Io to a plain file or device
18  *
19  * written by:
20  *
21  * Alain L. Knaff
22  * [email protected]
23  *
24  */
25 
26 #include "sysincludes.h"
27 #include "stream.h"
28 #include "mtools.h"
29 #include "msdos.h"
30 #include "open_image.h"
31 #include "devices.h"
32 #include "plain_io.h"
33 #include "llong.h"
34 
35 #ifdef HAVE_LINUX_FS_H
36 # include <linux/fs.h>
37 #endif
38 
39 typedef struct SimpleFile_t {
40     struct Stream_t head;
41 
42     struct MT_STAT statbuf;
43     int fd;
44     mt_off_t lastwhere;
45     int seekable;
46     int privileged;
47 #ifdef OS_hpux
48     int size_limited;
49 #endif
50 } SimpleFile_t;
51 
52 
53 #include "lockdev.h"
54 
55 typedef ssize_t (*iofn) (int, void *, size_t);
56 
file_io(SimpleFile_t * This,char * buf,mt_off_t where,size_t len,iofn io)57 static ssize_t file_io(SimpleFile_t *This, char *buf,
58 		       mt_off_t where, size_t len,
59 		       iofn io)
60 {
61 	ssize_t ret;
62 
63 	if (This->seekable && where != This->lastwhere ){
64 		if(mt_lseek( This->fd, where, SEEK_SET) < 0 ){
65 			perror("seek");
66 			return -1; /* If seek failed, lastwhere did
67 				      not change */
68 		}
69 		This->lastwhere = where;
70 	}
71 
72 #ifdef OS_hpux
73 	/*
74 	 * On HP/UX, we can not write more than MAX_LEN bytes in one go.
75 	 * If more are written, the write fails with EINVAL
76 	 */
77 	#define MAX_SCSI_LEN (127*1024)
78 	if(This->size_limited && len > MAX_SCSI_LEN)
79 		len = MAX_SCSI_LEN;
80 #endif
81 	ret = io(This->fd, buf, len);
82 
83 #ifdef OS_hpux
84 	if (ret == -1 &&
85 		errno == EINVAL && /* if we got EINVAL */
86 		len > MAX_SCSI_LEN) {
87 		This->size_limited = 1;
88 		len = MAX_SCSI_LEN;
89 		ret = io(This->fd, buf, len);
90 	}
91 #endif
92 
93 	if ( ret == -1 ){
94 		perror("plain_io");
95 		return -1;
96 	}
97 	This->lastwhere = where + ret;
98 	return ret;
99 }
100 
file_read(Stream_t * Stream,char * buf,size_t len)101 static ssize_t file_read(Stream_t *Stream, char *buf, size_t len)
102 {
103 	DeclareThis(SimpleFile_t);
104 	return file_io(This, buf, This->lastwhere, len, read);
105 }
106 
file_write(Stream_t * Stream,char * buf,size_t len)107 static ssize_t file_write(Stream_t *Stream, char *buf, size_t len)
108 {
109 	DeclareThis(SimpleFile_t);
110 	return file_io(This, buf, This->lastwhere, len, (iofn) write);
111 }
112 
file_pread(Stream_t * Stream,char * buf,mt_off_t where,size_t len)113 static ssize_t file_pread(Stream_t *Stream, char *buf,
114 			  mt_off_t where, size_t len)
115 {
116 	DeclareThis(SimpleFile_t);
117 	return file_io(This, buf, where, len, read);
118 }
119 
file_pwrite(Stream_t * Stream,char * buf,mt_off_t where,size_t len)120 static ssize_t file_pwrite(Stream_t *Stream, char *buf,
121 			   mt_off_t where, size_t len)
122 {
123 	DeclareThis(SimpleFile_t);
124 	return file_io(This, buf, where, len, (iofn) write);
125 }
126 
file_flush(Stream_t * Stream UNUSEDP)127 static int file_flush(Stream_t *Stream UNUSEDP)
128 {
129 #if 0
130 	DeclareThis(SimpleFile_t);
131 
132 	return fsync(This->fd);
133 #endif
134 	return 0;
135 }
136 
file_free(Stream_t * Stream)137 static int file_free(Stream_t *Stream)
138 {
139 	DeclareThis(SimpleFile_t);
140 
141 	if (This->fd > 2)
142 		return close(This->fd);
143 	else
144 		return 0;
145 }
146 
init_geom_with_reg(int fd,struct device * dev,struct device * orig_dev,struct MT_STAT * statbuf)147 static int init_geom_with_reg(int fd, struct device *dev,
148 			      struct device *orig_dev,
149 			      struct MT_STAT *statbuf) {
150 	if(S_ISREG(statbuf->st_mode)) {
151 		/* Regular file (image file) */
152 		mt_off_t sectors;
153 		if(statbuf->st_size == 0) {
154 			/* zero sized image => newly created.
155 			   Size not actually known...
156 			*/
157 			return 0;
158 		}
159 		sectors = statbuf->st_size /
160 			(mt_off_t)(dev->sector_size ? dev->sector_size : 512);
161 		dev->tot_sectors =
162 			((smt_off_t) sectors > UINT32_MAX)
163 			? UINT32_MAX
164 			: (uint32_t) sectors;
165 		return 0;
166 	} else {
167 		/* All the rest (devices, etc.) */
168 		return init_geom(fd, dev, orig_dev, statbuf);
169 	}
170 }
171 
file_geom(Stream_t * Stream,struct device * dev,struct device * orig_dev)172 static int file_geom(Stream_t *Stream, struct device *dev,
173 		     struct device *orig_dev)
174 {
175 	int ret;
176 	DeclareThis(SimpleFile_t);
177 
178 	if(dev->sector_size && dev->sector_size != 512) {
179 		dev->sectors =
180 			(uint16_t) (dev->sectors * dev->sector_size / 512);
181 	}
182 
183 #ifdef JPD
184 	printf("file_geom:media=%0X=>cyl=%d,heads=%d,sects=%d,ssize=%d,use2m=%X\n",
185 	       media, dev->tracks, dev->heads, dev->sectors, dev->ssize,
186 	       dev->use_2m);
187 #endif
188 	ret = init_geom_with_reg(This->fd,dev, orig_dev, &This->statbuf);
189 	if(dev->sector_size && dev->sector_size != 512) {
190 		dev->sectors =
191 			(uint16_t) (dev->sectors * 512 / dev->sector_size);
192 	}
193 #ifdef JPD
194 	printf("f_geom: after init_geom(), sects=%d\n", dev->sectors);
195 #endif
196 	return ret;
197 }
198 
199 
file_data(Stream_t * Stream,time_t * date,mt_off_t * size,int * type,uint32_t * address)200 static int file_data(Stream_t *Stream, time_t *date, mt_off_t *size,
201 		     int *type, uint32_t *address)
202 {
203 	DeclareThis(SimpleFile_t);
204 
205 	if(date)
206 		*date = This->statbuf.st_mtime;
207 	if(size)
208 		*size = This->statbuf.st_size;
209 	if(type)
210 		*type = S_ISDIR(This->statbuf.st_mode);
211 	if(address)
212 		*address = 0;
213 	return 0;
214 }
215 
file_discard(Stream_t * Stream UNUSEDP)216 static int file_discard(Stream_t *Stream UNUSEDP)
217 {
218 #ifdef BLKFLSBUF
219 	int ret;
220 	DeclareThis(SimpleFile_t);
221 	ret= ioctl(This->fd, BLKFLSBUF);
222 	if(ret < 0)
223 		perror("BLKFLSBUF");
224 	return ret;
225 #else
226 	return 0;
227 #endif
228 }
229 
230 static Class_t SimpleFileClass = {
231 	file_read,
232 	file_write,
233 	file_pread,
234 	file_pwrite,
235 	file_flush,
236 	file_free,
237 	file_geom,
238 	file_data,
239 	0, /* pre_allocate */
240 	0, /* dos-convert */
241 	file_discard
242 };
243 
244 
LockDevice(int fd,struct device * dev,int locked,int lockMode,char * errmsg)245 int LockDevice(int fd, struct device *dev,
246 	       int locked, int lockMode,
247 	       char *errmsg)
248 {
249 #ifndef __EMX__
250 #ifndef __CYGWIN__
251 #ifndef OS_mingw32msvc
252 	/* lock the device on writes */
253 	if (locked && lock_dev(fd, (lockMode&O_ACCMODE) == O_RDWR, dev)) {
254 		if(errmsg)
255 #ifdef HAVE_SNPRINTF
256 			snprintf(errmsg,199,
257 				"plain floppy: device \"%s\" busy (%s):",
258 				dev ? dev->name : "unknown", strerror(errno));
259 #else
260 			sprintf(errmsg,
261 				"plain floppy: device \"%s\" busy (%s):",
262 				(dev && strlen(dev->name) < 50) ?
263 				 dev->name : "unknown", strerror(errno));
264 #endif
265 
266 		if(errno != EOPNOTSUPP || (lockMode&O_ACCMODE) == O_RDWR) {
267 			/* If error is "not supported", and we're only
268 			 * reading from the device anyways, then ignore. Some
269 			 * OS'es don't support locks on read-only devices, even
270 			 * if they are shared (read-only) locks */
271 			return -1;
272 		}
273 	}
274 #endif
275 #endif
276 #endif
277 	return 0;
278 }
279 
SimpleFileOpen(struct device * dev,struct device * orig_dev,const char * name,int mode,char * errmsg,int mode2,int locked,mt_off_t * maxSize)280 Stream_t *SimpleFileOpen(struct device *dev, struct device *orig_dev,
281 			 const char *name, int mode, char *errmsg,
282 			 int mode2, int locked, mt_off_t *maxSize) {
283 	return SimpleFileOpenWithLm(dev, orig_dev, name, mode,
284 				    errmsg, mode2, locked, mode, maxSize,
285 				    NULL);
286 }
287 
SimpleFileOpenWithLm(struct device * dev,struct device * orig_dev,const char * name,int mode,char * errmsg,int mode2,int locked,int lockMode,mt_off_t * maxSize,int * geomFailure)288 Stream_t *SimpleFileOpenWithLm(struct device *dev, struct device *orig_dev,
289 			       const char *name, int mode, char *errmsg,
290 			       int mode2, int locked, int lockMode,
291 			       mt_off_t *maxSize, int *geomFailure)
292 {
293 	SimpleFile_t *This;
294 #ifdef __EMX__
295 HFILE FileHandle;
296 ULONG Action;
297 APIRET rc;
298 #endif
299 	if (IS_SCSI(dev))
300 		return NULL;
301 	This = New(SimpleFile_t);
302 	if (!This){
303 		printOom();
304 		return 0;
305 	}
306 	memset((void*)This, 0, sizeof(SimpleFile_t));
307 	This->seekable = 1;
308 #ifdef OS_hpux
309 	This->size_limited = 0;
310 #endif
311 	init_head(&This->head, &SimpleFileClass, NULL);
312 	if (!name || strcmp(name,"-") == 0 ){
313 		if (mode == O_RDONLY)
314 			This->fd = 0;
315 		else
316 			This->fd = 1;
317 		This->seekable = 0;
318 		if (MT_FSTAT(This->fd, &This->statbuf) < 0) {
319 		    Free(This);
320 		    if(errmsg)
321 #ifdef HAVE_SNPRINTF
322 			snprintf(errmsg,199,"Can't stat -: %s",
323 				strerror(errno));
324 #else
325 			sprintf(errmsg,"Can't stat -: %s",
326 				strerror(errno));
327 #endif
328 		    return NULL;
329 		}
330 
331 		return &This->head;
332 	}
333 
334 
335 	if(dev) {
336 		if(!(mode2 & NO_PRIV))
337 			This->privileged = IS_PRIVILEGED(dev);
338 		mode |= dev->mode;
339 	}
340 
341 	precmd(dev);
342 	if(IS_PRIVILEGED(dev) && !(mode2 & NO_PRIV))
343 		reclaim_privs();
344 
345 #ifdef __EMX__
346 #define DOSOPEN_FLAGS	(OPEN_FLAGS_DASD | OPEN_FLAGS_WRITE_THROUGH | \
347 			OPEN_FLAGS_NOINHERIT | OPEN_FLAGS_RANDOM | \
348 			OPEN_FLAGS_NO_CACHE)
349 #define DOSOPEN_FD_ACCESS (OPEN_SHARE_DENYREADWRITE | OPEN_ACCESS_READWRITE)
350 #define DOSOPEN_HD_ACCESS (OPEN_SHARE_DENYNONE | OPEN_ACCESS_READONLY)
351 
352 	if (isalpha(*name) && (*(name+1) == ':')) {
353 		rc = DosOpen(
354 			name, &FileHandle, &Action, 0L, FILE_NORMAL,
355 			OPEN_ACTION_OPEN_IF_EXISTS, DOSOPEN_FLAGS |
356 			(IS_NOLOCK(dev)?DOSOPEN_HD_ACCESS:DOSOPEN_FD_ACCESS),
357 			0L);
358 #if DEBUG
359 		if (rc != NO_ERROR) fprintf (stderr, "DosOpen() returned %d\n", rc);
360 #endif
361 		if (!IS_NOLOCK(dev)) {
362 			rc = DosDevIOCtl(
363 			FileHandle, 0x08L, DSK_LOCKDRIVE, 0, 0, 0, 0, 0, 0);
364 #if DEBUG
365 			if (rc != NO_ERROR) fprintf (stderr, "DosDevIOCtl() returned %d\n", rc);
366 #endif
367 		}
368 		if (rc == NO_ERROR)
369 			This->fd = _imphandle(FileHandle); else This->fd = -1;
370 	} else
371 #endif
372 	    {
373 		    This->fd = open(name, mode | O_LARGEFILE | O_BINARY,
374 				    IS_NOLOCK(dev)?0444:0666);
375 	    }
376 
377 	if(IS_PRIVILEGED(dev) && !(mode2 & NO_PRIV))
378 		drop_privs();
379 
380 	if (This->fd < 0) {
381 		if(errmsg) {
382 #ifdef HAVE_SNPRINTF
383 			snprintf(errmsg, 199, "Can't open %s: %s",
384 				name, strerror(errno));
385 #else
386 			sprintf(errmsg, "Can't open %s: %s",
387 				name, strerror(errno));
388 #endif
389 		}
390 		goto exit_1;
391 	}
392 
393 	if(IS_PRIVILEGED(dev) && !(mode2 & NO_PRIV))
394 		closeExec(This->fd);
395 
396 #ifdef __EMX__
397 	if (*(name+1) != ':')
398 #endif
399 	if (MT_FSTAT(This->fd, &This->statbuf) < 0
400 #ifdef OS_mingw32msvc
401 	    && strncmp(name, "\\\\.\\", 4) != 0
402 #endif
403 	   ) {
404 		if(errmsg) {
405 #ifdef HAVE_SNPRINTF
406 			snprintf(errmsg,199,"Can't stat %s: %s",
407 				name, strerror(errno));
408 #else
409 			if(strlen(name) > 50) {
410 			    sprintf(errmsg,"Can't stat file: %s",
411 				    strerror(errno));
412 			} else {
413 			    sprintf(errmsg,"Can't stat %s: %s",
414 				name, strerror(errno));
415 			}
416 #endif
417 		}
418 		goto exit_0;
419 	}
420 
421 	if(LockDevice(This->fd, dev, locked, lockMode, errmsg) < 0)
422 		goto exit_0;
423 
424 	/* set default parameters, if needed */
425 	if (dev){
426 		errno=0;
427 		if (((!IS_MFORMAT_ONLY(dev) && dev->tracks) ||
428 		     mode2 & ALWAYS_GET_GEOMETRY) &&
429 		    init_geom_with_reg(This->fd, dev, orig_dev,
430 				       &This->statbuf)){
431 			if(geomFailure && (errno==EBADF || errno==EPERM)) {
432 				*geomFailure=1;
433 				return NULL;
434 			} else if(errmsg)
435 				sprintf(errmsg,"init: set default params");
436 			goto exit_0;
437 		}
438 	}
439 
440 	if(maxSize)
441 		*maxSize = max_off_t_seek;
442 
443 	This->lastwhere = 0;
444 
445 	return &This->head;
446  exit_0:
447 	close(This->fd);
448  exit_1:
449 	Free(This);
450 	return NULL;
451 }
452 
get_fd(Stream_t * Stream)453 int get_fd(Stream_t *Stream)
454 {
455 	Class_t *clazz;
456 	DeclareThis(SimpleFile_t);
457 	clazz = This->head.Class;
458 	if(clazz != &SimpleFileClass)
459 	  return -1;
460 	else
461 	  return This->fd;
462 }
463