xref: /linux/arch/um/os-Linux/file.c (revision 7f71507851fc7764b36a3221839607d3a45c2025) 
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 
259 int os_seek_file(int fd, unsigned long long offset)
260 {
261 	unsigned long long actual;
262 
263 	actual = lseek64(fd, offset, SEEK_SET);
264 	if (actual != offset)
265 		return -errno;
266 	return 0;
267 }
268 
269 int os_read_file(int fd, void *buf, int len)
270 {
271 	int n = read(fd, buf, len);
272 
273 	if (n < 0)
274 		return -errno;
275 	return n;
276 }
277 
278 int os_pread_file(int fd, void *buf, int len, unsigned long long offset)
279 {
280 	int n = pread(fd, buf, len, offset);
281 
282 	if (n < 0)
283 		return -errno;
284 	return n;
285 }
286 
287 int os_write_file(int fd, const void *buf, int len)
288 {
289 	int n = write(fd, (void *) buf, len);
290 
291 	if (n < 0)
292 		return -errno;
293 	return n;
294 }
295 
296 int os_sync_file(int fd)
297 {
298 	int n = fdatasync(fd);
299 
300 	if (n < 0)
301 		return -errno;
302 	return n;
303 }
304 
305 int os_pwrite_file(int fd, const void *buf, int len, unsigned long long offset)
306 {
307 	int n = pwrite(fd, (void *) buf, len, offset);
308 
309 	if (n < 0)
310 		return -errno;
311 	return n;
312 }
313 
314 
315 int os_file_size(const char *file, unsigned long long *size_out)
316 {
317 	struct uml_stat buf;
318 	int err;
319 
320 	err = os_stat_file(file, &buf);
321 	if (err < 0) {
322 		printk(UM_KERN_ERR "Couldn't stat \"%s\" : err = %d\n", file,
323 		       -err);
324 		return err;
325 	}
326 
327 	if (S_ISBLK(buf.ust_mode)) {
328 		int fd;
329 		long blocks;
330 
331 		fd = open(file, O_RDONLY, 0);
332 		if (fd < 0) {
333 			err = -errno;
334 			printk(UM_KERN_ERR "Couldn't open \"%s\", "
335 			       "errno = %d\n", file, errno);
336 			return err;
337 		}
338 		if (ioctl(fd, BLKGETSIZE, &blocks) < 0) {
339 			err = -errno;
340 			printk(UM_KERN_ERR "Couldn't get the block size of "
341 			       "\"%s\", errno = %d\n", file, errno);
342 			close(fd);
343 			return err;
344 		}
345 		*size_out = ((long long) blocks) * 512;
346 		close(fd);
347 	}
348 	else *size_out = buf.ust_size;
349 
350 	return 0;
351 }
352 
353 int os_file_modtime(const char *file, long long *modtime)
354 {
355 	struct uml_stat buf;
356 	int err;
357 
358 	err = os_stat_file(file, &buf);
359 	if (err < 0) {
360 		printk(UM_KERN_ERR "Couldn't stat \"%s\" : err = %d\n", file,
361 		       -err);
362 		return err;
363 	}
364 
365 	*modtime = buf.ust_mtime;
366 	return 0;
367 }
368 
369 int os_set_exec_close(int fd)
370 {
371 	int err;
372 
373 	CATCH_EINTR(err = fcntl(fd, F_SETFD, FD_CLOEXEC));
374 
375 	if (err < 0)
376 		return -errno;
377 	return err;
378 }
379 
380 int os_pipe(int *fds, int stream, int close_on_exec)
381 {
382 	int err, type = stream ? SOCK_STREAM : SOCK_DGRAM;
383 
384 	err = socketpair(AF_UNIX, type, 0, fds);
385 	if (err < 0)
386 		return -errno;
387 
388 	if (!close_on_exec)
389 		return 0;
390 
391 	err = os_set_exec_close(fds[0]);
392 	if (err < 0)
393 		goto error;
394 
395 	err = os_set_exec_close(fds[1]);
396 	if (err < 0)
397 		goto error;
398 
399 	return 0;
400 
401  error:
402 	printk(UM_KERN_ERR "os_pipe : Setting FD_CLOEXEC failed, err = %d\n",
403 	       -err);
404 	close(fds[1]);
405 	close(fds[0]);
406 	return err;
407 }
408 
409 int os_set_fd_async(int fd)
410 {
411 	int err, flags;
412 
413 	flags = fcntl(fd, F_GETFL);
414 	if (flags < 0)
415 		return -errno;
416 
417 	flags |= O_ASYNC | O_NONBLOCK;
418 	if (fcntl(fd, F_SETFL, flags) < 0) {
419 		err = -errno;
420 		printk(UM_KERN_ERR "os_set_fd_async : failed to set O_ASYNC "
421 		       "and O_NONBLOCK on fd # %d, errno = %d\n", fd, errno);
422 		return err;
423 	}
424 
425 	if ((fcntl(fd, F_SETSIG, SIGIO) < 0) ||
426 	    (fcntl(fd, F_SETOWN, os_getpid()) < 0)) {
427 		err = -errno;
428 		printk(UM_KERN_ERR "os_set_fd_async : Failed to fcntl F_SETOWN "
429 		       "(or F_SETSIG) fd %d, errno = %d\n", fd, errno);
430 		return err;
431 	}
432 
433 	return 0;
434 }
435 
436 int os_clear_fd_async(int fd)
437 {
438 	int flags;
439 
440 	flags = fcntl(fd, F_GETFL);
441 	if (flags < 0)
442 		return -errno;
443 
444 	flags &= ~(O_ASYNC | O_NONBLOCK);
445 	if (fcntl(fd, F_SETFL, flags) < 0)
446 		return -errno;
447 	return 0;
448 }
449 
450 int os_set_fd_block(int fd, int blocking)
451 {
452 	int flags;
453 
454 	flags = fcntl(fd, F_GETFL);
455 	if (flags < 0)
456 		return -errno;
457 
458 	if (blocking)
459 		flags &= ~O_NONBLOCK;
460 	else
461 		flags |= O_NONBLOCK;
462 
463 	if (fcntl(fd, F_SETFL, flags) < 0)
464 		return -errno;
465 
466 	return 0;
467 }
468 
469 int os_accept_connection(int fd)
470 {
471 	int new;
472 
473 	new = accept(fd, NULL, 0);
474 	if (new < 0)
475 		return -errno;
476 	return new;
477 }
478 
479 #ifndef SHUT_RD
480 #define SHUT_RD 0
481 #endif
482 
483 #ifndef SHUT_WR
484 #define SHUT_WR 1
485 #endif
486 
487 #ifndef SHUT_RDWR
488 #define SHUT_RDWR 2
489 #endif
490 
491 int os_shutdown_socket(int fd, int r, int w)
492 {
493 	int what, err;
494 
495 	if (r && w)
496 		what = SHUT_RDWR;
497 	else if (r)
498 		what = SHUT_RD;
499 	else if (w)
500 		what = SHUT_WR;
501 	else
502 		return -EINVAL;
503 
504 	err = shutdown(fd, what);
505 	if (err < 0)
506 		return -errno;
507 	return 0;
508 }
509 
510 /**
511  * os_rcv_fd_msg - receive message with (optional) FDs
512  * @fd: the FD to receive from
513  * @fds: the array for FDs to write to
514  * @n_fds: number of FDs to receive (@fds array size)
515  * @data: the message buffer
516  * @data_len: the size of the message to receive
517  *
518  * Receive a message with FDs.
519  *
520  * Returns: the size of the received message, or an error code
521  */
522 ssize_t os_rcv_fd_msg(int fd, int *fds, unsigned int n_fds,
523 		      void *data, size_t data_len)
524 {
525 #define MAX_RCV_FDS	2
526 	char buf[CMSG_SPACE(sizeof(*fds) * MAX_RCV_FDS)];
527 	struct cmsghdr *cmsg;
528 	struct iovec iov = {
529 		.iov_base = data,
530 		.iov_len = data_len,
531 	};
532 	struct msghdr msg = {
533 		.msg_iov = &iov,
534 		.msg_iovlen = 1,
535 		.msg_control = buf,
536 		.msg_controllen = CMSG_SPACE(sizeof(*fds) * n_fds),
537 	};
538 	int n;
539 
540 	if (n_fds > MAX_RCV_FDS)
541 		return -EINVAL;
542 
543 	n = recvmsg(fd, &msg, 0);
544 	if (n < 0)
545 		return -errno;
546 
547 	cmsg = CMSG_FIRSTHDR(&msg);
548 	if (!cmsg ||
549 	    cmsg->cmsg_level != SOL_SOCKET ||
550 	    cmsg->cmsg_type != SCM_RIGHTS)
551 		return n;
552 
553 	memcpy(fds, CMSG_DATA(cmsg), cmsg->cmsg_len);
554 	return n;
555 }
556 
557 int os_create_unix_socket(const char *file, int len, int close_on_exec)
558 {
559 	struct sockaddr_un addr;
560 	int sock, err;
561 
562 	sock = socket(PF_UNIX, SOCK_DGRAM, 0);
563 	if (sock < 0)
564 		return -errno;
565 
566 	if (close_on_exec) {
567 		err = os_set_exec_close(sock);
568 		if (err < 0)
569 			printk(UM_KERN_ERR "create_unix_socket : "
570 			       "close_on_exec failed, err = %d", -err);
571 	}
572 
573 	addr.sun_family = AF_UNIX;
574 
575 	snprintf(addr.sun_path, len, "%s", file);
576 
577 	err = bind(sock, (struct sockaddr *) &addr, sizeof(addr));
578 	if (err < 0)
579 		return -errno;
580 
581 	return sock;
582 }
583 
584 void os_flush_stdout(void)
585 {
586 	fflush(stdout);
587 }
588 
589 int os_lock_file(int fd, int excl)
590 {
591 	int type = excl ? F_WRLCK : F_RDLCK;
592 	struct flock lock = ((struct flock) { .l_type	= type,
593 					      .l_whence	= SEEK_SET,
594 					      .l_start	= 0,
595 					      .l_len	= 0 } );
596 	int err, save;
597 
598 	err = fcntl(fd, F_SETLK, &lock);
599 	if (!err)
600 		goto out;
601 
602 	save = -errno;
603 	err = fcntl(fd, F_GETLK, &lock);
604 	if (err) {
605 		err = -errno;
606 		goto out;
607 	}
608 
609 	printk(UM_KERN_ERR "F_SETLK failed, file already locked by pid %d\n",
610 	       lock.l_pid);
611 	err = save;
612  out:
613 	return err;
614 }
615 
616 unsigned os_major(unsigned long long dev)
617 {
618 	return major(dev);
619 }
620 
621 unsigned os_minor(unsigned long long dev)
622 {
623 	return minor(dev);
624 }
625 
626 unsigned long long os_makedev(unsigned major, unsigned minor)
627 {
628 	return makedev(major, minor);
629 }
630 
631 int os_falloc_punch(int fd, unsigned long long offset, int len)
632 {
633 	int n = fallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, offset, len);
634 
635 	if (n < 0)
636 		return -errno;
637 	return n;
638 }
639 
640 int os_falloc_zeroes(int fd, unsigned long long offset, int len)
641 {
642 	int n = fallocate(fd, FALLOC_FL_ZERO_RANGE|FALLOC_FL_KEEP_SIZE, offset, len);
643 
644 	if (n < 0)
645 		return -errno;
646 	return n;
647 }
648 
649 int os_eventfd(unsigned int initval, int flags)
650 {
651 	int fd = eventfd(initval, flags);
652 
653 	if (fd < 0)
654 		return -errno;
655 	return fd;
656 }
657 
658 int os_sendmsg_fds(int fd, const void *buf, unsigned int len, const int *fds,
659 		   unsigned int fds_num)
660 {
661 	struct iovec iov = {
662 		.iov_base = (void *) buf,
663 		.iov_len = len,
664 	};
665 	union {
666 		char control[CMSG_SPACE(sizeof(*fds) * OS_SENDMSG_MAX_FDS)];
667 		struct cmsghdr align;
668 	} u;
669 	unsigned int fds_size = sizeof(*fds) * fds_num;
670 	struct msghdr msg = {
671 		.msg_iov = &iov,
672 		.msg_iovlen = 1,
673 		.msg_control = u.control,
674 		.msg_controllen = CMSG_SPACE(fds_size),
675 	};
676 	struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
677 	int err;
678 
679 	if (fds_num > OS_SENDMSG_MAX_FDS)
680 		return -EINVAL;
681 	memset(u.control, 0, sizeof(u.control));
682 	cmsg->cmsg_level = SOL_SOCKET;
683 	cmsg->cmsg_type = SCM_RIGHTS;
684 	cmsg->cmsg_len = CMSG_LEN(fds_size);
685 	memcpy(CMSG_DATA(cmsg), fds, fds_size);
686 	err = sendmsg(fd, &msg, 0);
687 
688 	if (err < 0)
689 		return -errno;
690 	return err;
691 }
692 
693 int os_poll(unsigned int n, const int *fds)
694 {
695 	/* currently need 2 FDs at most so avoid dynamic allocation */
696 	struct pollfd pollfds[2] = {};
697 	unsigned int i;
698 	int ret;
699 
700 	if (n > ARRAY_SIZE(pollfds))
701 		return -EINVAL;
702 
703 	for (i = 0; i < n; i++) {
704 		pollfds[i].fd = fds[i];
705 		pollfds[i].events = POLLIN;
706 	}
707 
708 	ret = poll(pollfds, n, -1);
709 	if (ret < 0)
710 		return -errno;
711 
712 	/* Return the index of the available FD */
713 	for (i = 0; i < n; i++) {
714 		if (pollfds[i].revents)
715 			return i;
716 	}
717 
718 	return -EIO;
719 }
720 
721 void *os_mmap_rw_shared(int fd, size_t size)
722 {
723 	void *res = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
724 
725 	if (res == MAP_FAILED)
726 		return NULL;
727 
728 	return res;
729 }
730 
731 void *os_mremap_rw_shared(void *old_addr, size_t old_size, size_t new_size)
732 {
733 	void *res;
734 
735 	res = mremap(old_addr, old_size, new_size, MREMAP_MAYMOVE, NULL);
736 
737 	if (res == MAP_FAILED)
738 		return NULL;
739 
740 	return res;
741 }
742