arch/um/os-Linux/file.c

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