xref: /linux/arch/um/os-Linux/file.c (revision d53b8e36925256097a08d7cb749198d85cbf9b2b) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4  */
5 
6 #include <stdio.h>
7 #include <unistd.h>
8 #include <stdlib.h>
9 #include <string.h>
10 #include <errno.h>
11 #include <fcntl.h>
12 #include <signal.h>
13 #include <linux/falloc.h>
14 #include <sys/ioctl.h>
15 #include <sys/mount.h>
16 #include <sys/socket.h>
17 #include <sys/stat.h>
18 #include <sys/sysmacros.h>
19 #include <sys/un.h>
20 #include <sys/mman.h>
21 #include <sys/types.h>
22 #include <sys/eventfd.h>
23 #include <poll.h>
24 #include <os.h>
25 
26 static void copy_stat(struct uml_stat *dst, const struct stat64 *src)
27 {
28 	*dst = ((struct uml_stat) {
29 		.ust_dev     = src->st_dev,     /* device */
30 		.ust_ino     = src->st_ino,     /* inode */
31 		.ust_mode    = src->st_mode,    /* protection */
32 		.ust_nlink   = src->st_nlink,   /* number of hard links */
33 		.ust_uid     = src->st_uid,     /* user ID of owner */
34 		.ust_gid     = src->st_gid,     /* group ID of owner */
35 		.ust_size    = src->st_size,    /* total size, in bytes */
36 		.ust_blksize = src->st_blksize, /* blocksize for filesys I/O */
37 		.ust_blocks  = src->st_blocks,  /* number of blocks allocated */
38 		.ust_atime   = src->st_atime,   /* time of last access */
39 		.ust_mtime   = src->st_mtime,   /* time of last modification */
40 		.ust_ctime   = src->st_ctime,   /* time of last change */
41 	});
42 }
43 
44 int os_stat_fd(const int fd, struct uml_stat *ubuf)
45 {
46 	struct stat64 sbuf;
47 	int err;
48 
49 	CATCH_EINTR(err = fstat64(fd, &sbuf));
50 	if (err < 0)
51 		return -errno;
52 
53 	if (ubuf != NULL)
54 		copy_stat(ubuf, &sbuf);
55 	return err;
56 }
57 
58 int os_stat_file(const char *file_name, struct uml_stat *ubuf)
59 {
60 	struct stat64 sbuf;
61 	int err;
62 
63 	CATCH_EINTR(err = stat64(file_name, &sbuf));
64 	if (err < 0)
65 		return -errno;
66 
67 	if (ubuf != NULL)
68 		copy_stat(ubuf, &sbuf);
69 	return err;
70 }
71 
72 int os_access(const char *file, int mode)
73 {
74 	int amode, err;
75 
76 	amode = (mode & OS_ACC_R_OK ? R_OK : 0) |
77 		(mode & OS_ACC_W_OK ? W_OK : 0) |
78 		(mode & OS_ACC_X_OK ? X_OK : 0) |
79 		(mode & OS_ACC_F_OK ? F_OK : 0);
80 
81 	err = access(file, amode);
82 	if (err < 0)
83 		return -errno;
84 
85 	return 0;
86 }
87 
88 /* FIXME? required only by hostaudio (because it passes ioctls verbatim) */
89 int os_ioctl_generic(int fd, unsigned int cmd, unsigned long arg)
90 {
91 	int err;
92 
93 	err = ioctl(fd, cmd, arg);
94 	if (err < 0)
95 		return -errno;
96 
97 	return err;
98 }
99 
100 /* FIXME: ensure namebuf in os_get_if_name is big enough */
101 int os_get_ifname(int fd, char* namebuf)
102 {
103 	if (ioctl(fd, SIOCGIFNAME, namebuf) < 0)
104 		return -errno;
105 
106 	return 0;
107 }
108 
109 int os_set_slip(int fd)
110 {
111 	int disc, sencap;
112 
113 	disc = N_SLIP;
114 	if (ioctl(fd, TIOCSETD, &disc) < 0)
115 		return -errno;
116 
117 	sencap = 0;
118 	if (ioctl(fd, SIOCSIFENCAP, &sencap) < 0)
119 		return -errno;
120 
121 	return 0;
122 }
123 
124 int os_mode_fd(int fd, int mode)
125 {
126 	int err;
127 
128 	CATCH_EINTR(err = fchmod(fd, mode));
129 	if (err < 0)
130 		return -errno;
131 
132 	return 0;
133 }
134 
135 int os_file_type(char *file)
136 {
137 	struct uml_stat buf;
138 	int err;
139 
140 	err = os_stat_file(file, &buf);
141 	if (err < 0)
142 		return err;
143 
144 	if (S_ISDIR(buf.ust_mode))
145 		return OS_TYPE_DIR;
146 	else if (S_ISLNK(buf.ust_mode))
147 		return OS_TYPE_SYMLINK;
148 	else if (S_ISCHR(buf.ust_mode))
149 		return OS_TYPE_CHARDEV;
150 	else if (S_ISBLK(buf.ust_mode))
151 		return OS_TYPE_BLOCKDEV;
152 	else if (S_ISFIFO(buf.ust_mode))
153 		return OS_TYPE_FIFO;
154 	else if (S_ISSOCK(buf.ust_mode))
155 		return OS_TYPE_SOCK;
156 	else return OS_TYPE_FILE;
157 }
158 
159 int os_file_mode(const char *file, struct openflags *mode_out)
160 {
161 	int err;
162 
163 	*mode_out = OPENFLAGS();
164 
165 	err = access(file, W_OK);
166 	if (err && (errno != EACCES))
167 		return -errno;
168 	else if (!err)
169 		*mode_out = of_write(*mode_out);
170 
171 	err = access(file, R_OK);
172 	if (err && (errno != EACCES))
173 		return -errno;
174 	else if (!err)
175 		*mode_out = of_read(*mode_out);
176 
177 	return err;
178 }
179 
180 int os_open_file(const char *file, struct openflags flags, int mode)
181 {
182 	int fd, err, f = 0;
183 
184 	if (flags.r && flags.w)
185 		f = O_RDWR;
186 	else if (flags.r)
187 		f = O_RDONLY;
188 	else if (flags.w)
189 		f = O_WRONLY;
190 	else f = 0;
191 
192 	if (flags.s)
193 		f |= O_SYNC;
194 	if (flags.c)
195 		f |= O_CREAT;
196 	if (flags.t)
197 		f |= O_TRUNC;
198 	if (flags.e)
199 		f |= O_EXCL;
200 	if (flags.a)
201 		f |= O_APPEND;
202 
203 	fd = open64(file, f, mode);
204 	if (fd < 0)
205 		return -errno;
206 
207 	if (flags.cl && fcntl(fd, F_SETFD, 1)) {
208 		err = -errno;
209 		close(fd);
210 		return err;
211 	}
212 
213 	return fd;
214 }
215 
216 int os_connect_socket(const char *name)
217 {
218 	struct sockaddr_un sock;
219 	int fd, err;
220 
221 	sock.sun_family = AF_UNIX;
222 	snprintf(sock.sun_path, sizeof(sock.sun_path), "%s", name);
223 
224 	fd = socket(AF_UNIX, SOCK_STREAM, 0);
225 	if (fd < 0) {
226 		err = -errno;
227 		goto out;
228 	}
229 
230 	err = connect(fd, (struct sockaddr *) &sock, sizeof(sock));
231 	if (err) {
232 		err = -errno;
233 		goto out_close;
234 	}
235 
236 	return fd;
237 
238 out_close:
239 	close(fd);
240 out:
241 	return err;
242 }
243 
244 int os_dup_file(int fd)
245 {
246 	int new_fd = dup(fd);
247 
248 	if (new_fd < 0)
249 		return -errno;
250 
251 	return new_fd;
252 }
253 
254 void os_close_file(int fd)
255 {
256 	close(fd);
257 }
258 int os_fsync_file(int fd)
259 {
260 	if (fsync(fd) < 0)
261 	    return -errno;
262 	return 0;
263 }
264 
265 int os_seek_file(int fd, unsigned long long offset)
266 {
267 	unsigned long long actual;
268 
269 	actual = lseek64(fd, offset, SEEK_SET);
270 	if (actual != offset)
271 		return -errno;
272 	return 0;
273 }
274 
275 int os_read_file(int fd, void *buf, int len)
276 {
277 	int n = read(fd, buf, len);
278 
279 	if (n < 0)
280 		return -errno;
281 	return n;
282 }
283 
284 int os_pread_file(int fd, void *buf, int len, unsigned long long offset)
285 {
286 	int n = pread(fd, buf, len, offset);
287 
288 	if (n < 0)
289 		return -errno;
290 	return n;
291 }
292 
293 int os_write_file(int fd, const void *buf, int len)
294 {
295 	int n = write(fd, (void *) buf, len);
296 
297 	if (n < 0)
298 		return -errno;
299 	return n;
300 }
301 
302 int os_sync_file(int fd)
303 {
304 	int n = fdatasync(fd);
305 
306 	if (n < 0)
307 		return -errno;
308 	return n;
309 }
310 
311 int os_pwrite_file(int fd, const void *buf, int len, unsigned long long offset)
312 {
313 	int n = pwrite(fd, (void *) buf, len, offset);
314 
315 	if (n < 0)
316 		return -errno;
317 	return n;
318 }
319 
320 
321 int os_file_size(const char *file, unsigned long long *size_out)
322 {
323 	struct uml_stat buf;
324 	int err;
325 
326 	err = os_stat_file(file, &buf);
327 	if (err < 0) {
328 		printk(UM_KERN_ERR "Couldn't stat \"%s\" : err = %d\n", file,
329 		       -err);
330 		return err;
331 	}
332 
333 	if (S_ISBLK(buf.ust_mode)) {
334 		int fd;
335 		long blocks;
336 
337 		fd = open(file, O_RDONLY, 0);
338 		if (fd < 0) {
339 			err = -errno;
340 			printk(UM_KERN_ERR "Couldn't open \"%s\", "
341 			       "errno = %d\n", file, errno);
342 			return err;
343 		}
344 		if (ioctl(fd, BLKGETSIZE, &blocks) < 0) {
345 			err = -errno;
346 			printk(UM_KERN_ERR "Couldn't get the block size of "
347 			       "\"%s\", errno = %d\n", file, errno);
348 			close(fd);
349 			return err;
350 		}
351 		*size_out = ((long long) blocks) * 512;
352 		close(fd);
353 	}
354 	else *size_out = buf.ust_size;
355 
356 	return 0;
357 }
358 
359 int os_file_modtime(const char *file, long long *modtime)
360 {
361 	struct uml_stat buf;
362 	int err;
363 
364 	err = os_stat_file(file, &buf);
365 	if (err < 0) {
366 		printk(UM_KERN_ERR "Couldn't stat \"%s\" : err = %d\n", file,
367 		       -err);
368 		return err;
369 	}
370 
371 	*modtime = buf.ust_mtime;
372 	return 0;
373 }
374 
375 int os_set_exec_close(int fd)
376 {
377 	int err;
378 
379 	CATCH_EINTR(err = fcntl(fd, F_SETFD, FD_CLOEXEC));
380 
381 	if (err < 0)
382 		return -errno;
383 	return err;
384 }
385 
386 int os_pipe(int *fds, int stream, int close_on_exec)
387 {
388 	int err, type = stream ? SOCK_STREAM : SOCK_DGRAM;
389 
390 	err = socketpair(AF_UNIX, type, 0, fds);
391 	if (err < 0)
392 		return -errno;
393 
394 	if (!close_on_exec)
395 		return 0;
396 
397 	err = os_set_exec_close(fds[0]);
398 	if (err < 0)
399 		goto error;
400 
401 	err = os_set_exec_close(fds[1]);
402 	if (err < 0)
403 		goto error;
404 
405 	return 0;
406 
407  error:
408 	printk(UM_KERN_ERR "os_pipe : Setting FD_CLOEXEC failed, err = %d\n",
409 	       -err);
410 	close(fds[1]);
411 	close(fds[0]);
412 	return err;
413 }
414 
415 int os_set_fd_async(int fd)
416 {
417 	int err, flags;
418 
419 	flags = fcntl(fd, F_GETFL);
420 	if (flags < 0)
421 		return -errno;
422 
423 	flags |= O_ASYNC | O_NONBLOCK;
424 	if (fcntl(fd, F_SETFL, flags) < 0) {
425 		err = -errno;
426 		printk(UM_KERN_ERR "os_set_fd_async : failed to set O_ASYNC "
427 		       "and O_NONBLOCK on fd # %d, errno = %d\n", fd, errno);
428 		return err;
429 	}
430 
431 	if ((fcntl(fd, F_SETSIG, SIGIO) < 0) ||
432 	    (fcntl(fd, F_SETOWN, os_getpid()) < 0)) {
433 		err = -errno;
434 		printk(UM_KERN_ERR "os_set_fd_async : Failed to fcntl F_SETOWN "
435 		       "(or F_SETSIG) fd %d, errno = %d\n", fd, errno);
436 		return err;
437 	}
438 
439 	return 0;
440 }
441 
442 int os_clear_fd_async(int fd)
443 {
444 	int flags;
445 
446 	flags = fcntl(fd, F_GETFL);
447 	if (flags < 0)
448 		return -errno;
449 
450 	flags &= ~(O_ASYNC | O_NONBLOCK);
451 	if (fcntl(fd, F_SETFL, flags) < 0)
452 		return -errno;
453 	return 0;
454 }
455 
456 int os_set_fd_block(int fd, int blocking)
457 {
458 	int flags;
459 
460 	flags = fcntl(fd, F_GETFL);
461 	if (flags < 0)
462 		return -errno;
463 
464 	if (blocking)
465 		flags &= ~O_NONBLOCK;
466 	else
467 		flags |= O_NONBLOCK;
468 
469 	if (fcntl(fd, F_SETFL, flags) < 0)
470 		return -errno;
471 
472 	return 0;
473 }
474 
475 int os_accept_connection(int fd)
476 {
477 	int new;
478 
479 	new = accept(fd, NULL, 0);
480 	if (new < 0)
481 		return -errno;
482 	return new;
483 }
484 
485 #ifndef SHUT_RD
486 #define SHUT_RD 0
487 #endif
488 
489 #ifndef SHUT_WR
490 #define SHUT_WR 1
491 #endif
492 
493 #ifndef SHUT_RDWR
494 #define SHUT_RDWR 2
495 #endif
496 
497 int os_shutdown_socket(int fd, int r, int w)
498 {
499 	int what, err;
500 
501 	if (r && w)
502 		what = SHUT_RDWR;
503 	else if (r)
504 		what = SHUT_RD;
505 	else if (w)
506 		what = SHUT_WR;
507 	else
508 		return -EINVAL;
509 
510 	err = shutdown(fd, what);
511 	if (err < 0)
512 		return -errno;
513 	return 0;
514 }
515 
516 /**
517  * os_rcv_fd_msg - receive message with (optional) FDs
518  * @fd: the FD to receive from
519  * @fds: the array for FDs to write to
520  * @n_fds: number of FDs to receive (@fds array size)
521  * @data: the message buffer
522  * @data_len: the size of the message to receive
523  *
524  * Receive a message with FDs.
525  *
526  * Returns: the size of the received message, or an error code
527  */
528 ssize_t os_rcv_fd_msg(int fd, int *fds, unsigned int n_fds,
529 		      void *data, size_t data_len)
530 {
531 	char buf[CMSG_SPACE(sizeof(*fds) * n_fds)];
532 	struct cmsghdr *cmsg;
533 	struct iovec iov = {
534 		.iov_base = data,
535 		.iov_len = data_len,
536 	};
537 	struct msghdr msg = {
538 		.msg_iov = &iov,
539 		.msg_iovlen = 1,
540 		.msg_control = buf,
541 		.msg_controllen = sizeof(buf),
542 	};
543 	int n;
544 
545 	n = recvmsg(fd, &msg, 0);
546 	if (n < 0)
547 		return -errno;
548 
549 	cmsg = CMSG_FIRSTHDR(&msg);
550 	if (!cmsg ||
551 	    cmsg->cmsg_level != SOL_SOCKET ||
552 	    cmsg->cmsg_type != SCM_RIGHTS)
553 		return n;
554 
555 	memcpy(fds, CMSG_DATA(cmsg), cmsg->cmsg_len);
556 	return n;
557 }
558 
559 int os_create_unix_socket(const char *file, int len, int close_on_exec)
560 {
561 	struct sockaddr_un addr;
562 	int sock, err;
563 
564 	sock = socket(PF_UNIX, SOCK_DGRAM, 0);
565 	if (sock < 0)
566 		return -errno;
567 
568 	if (close_on_exec) {
569 		err = os_set_exec_close(sock);
570 		if (err < 0)
571 			printk(UM_KERN_ERR "create_unix_socket : "
572 			       "close_on_exec failed, err = %d", -err);
573 	}
574 
575 	addr.sun_family = AF_UNIX;
576 
577 	snprintf(addr.sun_path, len, "%s", file);
578 
579 	err = bind(sock, (struct sockaddr *) &addr, sizeof(addr));
580 	if (err < 0)
581 		return -errno;
582 
583 	return sock;
584 }
585 
586 void os_flush_stdout(void)
587 {
588 	fflush(stdout);
589 }
590 
591 int os_lock_file(int fd, int excl)
592 {
593 	int type = excl ? F_WRLCK : F_RDLCK;
594 	struct flock lock = ((struct flock) { .l_type	= type,
595 					      .l_whence	= SEEK_SET,
596 					      .l_start	= 0,
597 					      .l_len	= 0 } );
598 	int err, save;
599 
600 	err = fcntl(fd, F_SETLK, &lock);
601 	if (!err)
602 		goto out;
603 
604 	save = -errno;
605 	err = fcntl(fd, F_GETLK, &lock);
606 	if (err) {
607 		err = -errno;
608 		goto out;
609 	}
610 
611 	printk(UM_KERN_ERR "F_SETLK failed, file already locked by pid %d\n",
612 	       lock.l_pid);
613 	err = save;
614  out:
615 	return err;
616 }
617 
618 unsigned os_major(unsigned long long dev)
619 {
620 	return major(dev);
621 }
622 
623 unsigned os_minor(unsigned long long dev)
624 {
625 	return minor(dev);
626 }
627 
628 unsigned long long os_makedev(unsigned major, unsigned minor)
629 {
630 	return makedev(major, minor);
631 }
632 
633 int os_falloc_punch(int fd, unsigned long long offset, int len)
634 {
635 	int n = fallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, offset, len);
636 
637 	if (n < 0)
638 		return -errno;
639 	return n;
640 }
641 
642 int os_falloc_zeroes(int fd, unsigned long long offset, int len)
643 {
644 	int n = fallocate(fd, FALLOC_FL_ZERO_RANGE|FALLOC_FL_KEEP_SIZE, offset, len);
645 
646 	if (n < 0)
647 		return -errno;
648 	return n;
649 }
650 
651 int os_eventfd(unsigned int initval, int flags)
652 {
653 	int fd = eventfd(initval, flags);
654 
655 	if (fd < 0)
656 		return -errno;
657 	return fd;
658 }
659 
660 int os_sendmsg_fds(int fd, const void *buf, unsigned int len, const int *fds,
661 		   unsigned int fds_num)
662 {
663 	struct iovec iov = {
664 		.iov_base = (void *) buf,
665 		.iov_len = len,
666 	};
667 	union {
668 		char control[CMSG_SPACE(sizeof(*fds) * OS_SENDMSG_MAX_FDS)];
669 		struct cmsghdr align;
670 	} u;
671 	unsigned int fds_size = sizeof(*fds) * fds_num;
672 	struct msghdr msg = {
673 		.msg_iov = &iov,
674 		.msg_iovlen = 1,
675 		.msg_control = u.control,
676 		.msg_controllen = CMSG_SPACE(fds_size),
677 	};
678 	struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
679 	int err;
680 
681 	if (fds_num > OS_SENDMSG_MAX_FDS)
682 		return -EINVAL;
683 	memset(u.control, 0, sizeof(u.control));
684 	cmsg->cmsg_level = SOL_SOCKET;
685 	cmsg->cmsg_type = SCM_RIGHTS;
686 	cmsg->cmsg_len = CMSG_LEN(fds_size);
687 	memcpy(CMSG_DATA(cmsg), fds, fds_size);
688 	err = sendmsg(fd, &msg, 0);
689 
690 	if (err < 0)
691 		return -errno;
692 	return err;
693 }
694 
695 int os_poll(unsigned int n, const int *fds)
696 {
697 	/* currently need 2 FDs at most so avoid dynamic allocation */
698 	struct pollfd pollfds[2] = {};
699 	unsigned int i;
700 	int ret;
701 
702 	if (n > ARRAY_SIZE(pollfds))
703 		return -EINVAL;
704 
705 	for (i = 0; i < n; i++) {
706 		pollfds[i].fd = fds[i];
707 		pollfds[i].events = POLLIN;
708 	}
709 
710 	ret = poll(pollfds, n, -1);
711 	if (ret < 0)
712 		return -errno;
713 
714 	/* Return the index of the available FD */
715 	for (i = 0; i < n; i++) {
716 		if (pollfds[i].revents)
717 			return i;
718 	}
719 
720 	return -EIO;
721 }
722 
723 void *os_mmap_rw_shared(int fd, size_t size)
724 {
725 	void *res = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
726 
727 	if (res == MAP_FAILED)
728 		return NULL;
729 
730 	return res;
731 }
732 
733 void *os_mremap_rw_shared(void *old_addr, size_t old_size, size_t new_size)
734 {
735 	void *res;
736 
737 	res = mremap(old_addr, old_size, new_size, MREMAP_MAYMOVE, NULL);
738 
739 	if (res == MAP_FAILED)
740 		return NULL;
741 
742 	return res;
743 }
744