hw/virtio-9p-local.c

   1 /*
   2  * Virtio 9p Posix callback
   3  *
   4  * Copyright IBM, Corp. 2010
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13 #include "virtio.h"
  14 #include "virtio-9p.h"
  15 #include "virtio-9p-xattr.h"
  16 #include <arpa/inet.h>
  17 #include <pwd.h>
  18 #include <grp.h>
  19 #include <sys/socket.h>
  20 #include <sys/un.h>
  21 #include <attr/xattr.h>
  22
  23
  24 static int local_lstat(FsContext *fs_ctx, const char *path, struct stat *stbuf)
  25 {
  26     int err;
  27     err =  lstat(rpath(fs_ctx, path), stbuf);
  28     if (err) {
  29         return err;
  30     }
  31     if (fs_ctx->fs_sm == SM_MAPPED) {
  32         /* Actual credentials are part of extended attrs */
  33         uid_t tmp_uid;
  34         gid_t tmp_gid;
  35         mode_t tmp_mode;
  36         dev_t tmp_dev;
  37         if (getxattr(rpath(fs_ctx, path), "user.virtfs.uid", &tmp_uid,
  38                     sizeof(uid_t)) > 0) {
  39             stbuf->st_uid = tmp_uid;
  40         }
  41         if (getxattr(rpath(fs_ctx, path), "user.virtfs.gid", &tmp_gid,
  42                     sizeof(gid_t)) > 0) {
  43             stbuf->st_gid = tmp_gid;
  44         }
  45         if (getxattr(rpath(fs_ctx, path), "user.virtfs.mode", &tmp_mode,
  46                     sizeof(mode_t)) > 0) {
  47             stbuf->st_mode = tmp_mode;
  48         }
  49         if (getxattr(rpath(fs_ctx, path), "user.virtfs.rdev", &tmp_dev,
  50                         sizeof(dev_t)) > 0) {
  51                 stbuf->st_rdev = tmp_dev;
  52         }
  53     }
  54     return err;
  55 }
  56
  57 static int local_set_xattr(const char *path, FsCred *credp)
  58 {
  59     int err;
  60     if (credp->fc_uid != -1) {
  61         err = setxattr(path, "user.virtfs.uid", &credp->fc_uid, sizeof(uid_t),
  62                 0);
  63         if (err) {
  64             return err;
  65         }
  66     }
  67     if (credp->fc_gid != -1) {
  68         err = setxattr(path, "user.virtfs.gid", &credp->fc_gid, sizeof(gid_t),
  69                 0);
  70         if (err) {
  71             return err;
  72         }
  73     }
  74     if (credp->fc_mode != -1) {
  75         err = setxattr(path, "user.virtfs.mode", &credp->fc_mode,
  76                 sizeof(mode_t), 0);
  77         if (err) {
  78             return err;
  79         }
  80     }
  81     if (credp->fc_rdev != -1) {
  82         err = setxattr(path, "user.virtfs.rdev", &credp->fc_rdev,
  83                 sizeof(dev_t), 0);
  84         if (err) {
  85             return err;
  86         }
  87     }
  88     return 0;
  89 }
  90
  91 static int local_post_create_passthrough(FsContext *fs_ctx, const char *path,
  92         FsCred *credp)
  93 {
  94     if (chmod(rpath(fs_ctx, path), credp->fc_mode & 07777) < 0) {
  95         return -1;
  96     }
  97     if (lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid) < 0) {
  98         /*
  99          * If we fail to change ownership and if we are
 100          * using security model none. Ignore the error
 101          */
 102         if (fs_ctx->fs_sm != SM_NONE) {
 103             return -1;
 104         }
 105     }
 106     return 0;
 107 }
 108
 109 static ssize_t local_readlink(FsContext *fs_ctx, const char *path,
 110         char *buf, size_t bufsz)
 111 {
 112     ssize_t tsize = -1;
 113     if (fs_ctx->fs_sm == SM_MAPPED) {
 114         int fd;
 115         fd = open(rpath(fs_ctx, path), O_RDONLY);
 116         if (fd == -1) {
 117             return -1;
 118         }
 119         do {
 120             tsize = read(fd, (void *)buf, bufsz);
 121         } while (tsize == -1 && errno == EINTR);
 122         close(fd);
 123         return tsize;
 124     } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
 125                (fs_ctx->fs_sm == SM_NONE)) {
 126         tsize = readlink(rpath(fs_ctx, path), buf, bufsz);
 127     }
 128     return tsize;
 129 }
 130
 131 static int local_close(FsContext *ctx, int fd)
 132 {
 133     return close(fd);
 134 }
 135
 136 static int local_closedir(FsContext *ctx, DIR *dir)
 137 {
 138     return closedir(dir);
 139 }
 140
 141 static int local_open(FsContext *ctx, const char *path, int flags)
 142 {
 143     return open(rpath(ctx, path), flags);
 144 }
 145
 146 static DIR *local_opendir(FsContext *ctx, const char *path)
 147 {
 148     return opendir(rpath(ctx, path));
 149 }
 150
 151 static void local_rewinddir(FsContext *ctx, DIR *dir)
 152 {
 153     return rewinddir(dir);
 154 }
 155
 156 static off_t local_telldir(FsContext *ctx, DIR *dir)
 157 {
 158     return telldir(dir);
 159 }
 160
 161 static struct dirent *local_readdir(FsContext *ctx, DIR *dir)
 162 {
 163     return readdir(dir);
 164 }
 165
 166 static void local_seekdir(FsContext *ctx, DIR *dir, off_t off)
 167 {
 168     return seekdir(dir, off);
 169 }
 170
 171 static ssize_t local_preadv(FsContext *ctx, int fd, const struct iovec *iov,
 172                             int iovcnt, off_t offset)
 173 {
 174 #ifdef CONFIG_PREADV
 175     return preadv(fd, iov, iovcnt, offset);
 176 #else
 177     int err = lseek(fd, offset, SEEK_SET);
 178     if (err == -1) {
 179         return err;
 180     } else {
 181         return readv(fd, iov, iovcnt);
 182     }
 183 #endif
 184 }
 185
 186 static ssize_t local_pwritev(FsContext *ctx, int fd, const struct iovec *iov,
 187                             int iovcnt, off_t offset)
 188 {
 189 #ifdef CONFIG_PREADV
 190     return pwritev(fd, iov, iovcnt, offset);
 191 #else
 192     int err = lseek(fd, offset, SEEK_SET);
 193     if (err == -1) {
 194         return err;
 195     } else {
 196         return writev(fd, iov, iovcnt);
 197     }
 198 #endif
 199 }
 200
 201 static int local_chmod(FsContext *fs_ctx, const char *path, FsCred *credp)
 202 {
 203     if (fs_ctx->fs_sm == SM_MAPPED) {
 204         return local_set_xattr(rpath(fs_ctx, path), credp);
 205     } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
 206                (fs_ctx->fs_sm == SM_NONE)) {
 207         return chmod(rpath(fs_ctx, path), credp->fc_mode);
 208     }
 209     return -1;
 210 }
 211
 212 static int local_mknod(FsContext *fs_ctx, const char *path, FsCred *credp)
 213 {
 214     int err = -1;
 215     int serrno = 0;
 216
 217     /* Determine the security model */
 218     if (fs_ctx->fs_sm == SM_MAPPED) {
 219         err = mknod(rpath(fs_ctx, path), SM_LOCAL_MODE_BITS|S_IFREG, 0);
 220         if (err == -1) {
 221             return err;
 222         }
 223         local_set_xattr(rpath(fs_ctx, path), credp);
 224         if (err == -1) {
 225             serrno = errno;
 226             goto err_end;
 227         }
 228     } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
 229                (fs_ctx->fs_sm == SM_NONE)) {
 230         err = mknod(rpath(fs_ctx, path), credp->fc_mode, credp->fc_rdev);
 231         if (err == -1) {
 232             return err;
 233         }
 234         err = local_post_create_passthrough(fs_ctx, path, credp);
 235         if (err == -1) {
 236             serrno = errno;
 237             goto err_end;
 238         }
 239     }
 240     return err;
 241
 242 err_end:
 243     remove(rpath(fs_ctx, path));
 244     errno = serrno;
 245     return err;
 246 }
 247
 248 static int local_mkdir(FsContext *fs_ctx, const char *path, FsCred *credp)
 249 {
 250     int err = -1;
 251     int serrno = 0;
 252
 253     /* Determine the security model */
 254     if (fs_ctx->fs_sm == SM_MAPPED) {
 255         err = mkdir(rpath(fs_ctx, path), SM_LOCAL_DIR_MODE_BITS);
 256         if (err == -1) {
 257             return err;
 258         }
 259         credp->fc_mode = credp->fc_mode|S_IFDIR;
 260         err = local_set_xattr(rpath(fs_ctx, path), credp);
 261         if (err == -1) {
 262             serrno = errno;
 263             goto err_end;
 264         }
 265     } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
 266                (fs_ctx->fs_sm == SM_NONE)) {
 267         err = mkdir(rpath(fs_ctx, path), credp->fc_mode);
 268         if (err == -1) {
 269             return err;
 270         }
 271         err = local_post_create_passthrough(fs_ctx, path, credp);
 272         if (err == -1) {
 273             serrno = errno;
 274             goto err_end;
 275         }
 276     }
 277     return err;
 278
 279 err_end:
 280     remove(rpath(fs_ctx, path));
 281     errno = serrno;
 282     return err;
 283 }
 284
 285 static int local_fstat(FsContext *fs_ctx, int fd, struct stat *stbuf)
 286 {
 287     int err;
 288     err = fstat(fd, stbuf);
 289     if (err) {
 290         return err;
 291     }
 292     if (fs_ctx->fs_sm == SM_MAPPED) {
 293         /* Actual credentials are part of extended attrs */
 294         uid_t tmp_uid;
 295         gid_t tmp_gid;
 296         mode_t tmp_mode;
 297         dev_t tmp_dev;
 298
 299         if (fgetxattr(fd, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) {
 300             stbuf->st_uid = tmp_uid;
 301         }
 302         if (fgetxattr(fd, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) {
 303             stbuf->st_gid = tmp_gid;
 304         }
 305         if (fgetxattr(fd, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) {
 306             stbuf->st_mode = tmp_mode;
 307         }
 308         if (fgetxattr(fd, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) {
 309                 stbuf->st_rdev = tmp_dev;
 310         }
 311     }
 312     return err;
 313 }
 314
 315 static int local_open2(FsContext *fs_ctx, const char *path, int flags,
 316         FsCred *credp)
 317 {
 318     int fd = -1;
 319     int err = -1;
 320     int serrno = 0;
 321
 322     /* Determine the security model */
 323     if (fs_ctx->fs_sm == SM_MAPPED) {
 324         fd = open(rpath(fs_ctx, path), flags, SM_LOCAL_MODE_BITS);
 325         if (fd == -1) {
 326             return fd;
 327         }
 328         credp->fc_mode = credp->fc_mode|S_IFREG;
 329         /* Set cleint credentials in xattr */
 330         err = local_set_xattr(rpath(fs_ctx, path), credp);
 331         if (err == -1) {
 332             serrno = errno;
 333             goto err_end;
 334         }
 335     } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
 336                (fs_ctx->fs_sm == SM_NONE)) {
 337         fd = open(rpath(fs_ctx, path), flags, credp->fc_mode);
 338         if (fd == -1) {
 339             return fd;
 340         }
 341         err = local_post_create_passthrough(fs_ctx, path, credp);
 342         if (err == -1) {
 343             serrno = errno;
 344             goto err_end;
 345         }
 346     }
 347     return fd;
 348
 349 err_end:
 350     close(fd);
 351     remove(rpath(fs_ctx, path));
 352     errno = serrno;
 353     return err;
 354 }
 355
 356
 357 static int local_symlink(FsContext *fs_ctx, const char *oldpath,
 358         const char *newpath, FsCred *credp)
 359 {
 360     int err = -1;
 361     int serrno = 0;
 362
 363     /* Determine the security model */
 364     if (fs_ctx->fs_sm == SM_MAPPED) {
 365         int fd;
 366         ssize_t oldpath_size, write_size;
 367         fd = open(rpath(fs_ctx, newpath), O_CREAT|O_EXCL|O_RDWR,
 368                 SM_LOCAL_MODE_BITS);
 369         if (fd == -1) {
 370             return fd;
 371         }
 372         /* Write the oldpath (target) to the file. */
 373         oldpath_size = strlen(oldpath) + 1;
 374         do {
 375             write_size = write(fd, (void *)oldpath, oldpath_size);
 376         } while (write_size == -1 && errno == EINTR);
 377
 378         if (write_size != oldpath_size) {
 379             serrno = errno;
 380             close(fd);
 381             err = -1;
 382             goto err_end;
 383         }
 384         close(fd);
 385         /* Set cleint credentials in symlink's xattr */
 386         credp->fc_mode = credp->fc_mode|S_IFLNK;
 387         err = local_set_xattr(rpath(fs_ctx, newpath), credp);
 388         if (err == -1) {
 389             serrno = errno;
 390             goto err_end;
 391         }
 392     } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
 393                (fs_ctx->fs_sm == SM_NONE)) {
 394         err = symlink(oldpath, rpath(fs_ctx, newpath));
 395         if (err) {
 396             return err;
 397         }
 398         err = lchown(rpath(fs_ctx, newpath), credp->fc_uid, credp->fc_gid);
 399         if (err == -1) {
 400             /*
 401              * If we fail to change ownership and if we are
 402              * using security model none. Ignore the error
 403              */
 404             if (fs_ctx->fs_sm != SM_NONE) {
 405                 serrno = errno;
 406                 goto err_end;
 407             } else
 408                 err = 0;
 409         }
 410     }
 411     return err;
 412
 413 err_end:
 414     remove(rpath(fs_ctx, newpath));
 415     errno = serrno;
 416     return err;
 417 }
 418
 419 static int local_link(FsContext *ctx, const char *oldpath, const char *newpath)
 420 {
 421     char *tmp = qemu_strdup(rpath(ctx, oldpath));
 422     int err, serrno = 0;
 423
 424     if (tmp == NULL) {
 425         return -ENOMEM;
 426     }
 427
 428     err = link(tmp, rpath(ctx, newpath));
 429     if (err == -1) {
 430         serrno = errno;
 431     }
 432
 433     qemu_free(tmp);
 434
 435     if (err == -1) {
 436         errno = serrno;
 437     }
 438
 439     return err;
 440 }
 441
 442 static int local_truncate(FsContext *ctx, const char *path, off_t size)
 443 {
 444     return truncate(rpath(ctx, path), size);
 445 }
 446
 447 static int local_rename(FsContext *ctx, const char *oldpath,
 448                         const char *newpath)
 449 {
 450     char *tmp;
 451     int err;
 452
 453     tmp = qemu_strdup(rpath(ctx, oldpath));
 454
 455     err = rename(tmp, rpath(ctx, newpath));
 456     if (err == -1) {
 457         int serrno = errno;
 458         qemu_free(tmp);
 459         errno = serrno;
 460     } else {
 461         qemu_free(tmp);
 462     }
 463
 464     return err;
 465
 466 }
 467
 468 static int local_chown(FsContext *fs_ctx, const char *path, FsCred *credp)
 469 {
 470     if ((credp->fc_uid == -1 && credp->fc_gid == -1) ||
 471             (fs_ctx->fs_sm == SM_PASSTHROUGH)) {
 472         return lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid);
 473     } else if (fs_ctx->fs_sm == SM_MAPPED) {
 474         return local_set_xattr(rpath(fs_ctx, path), credp);
 475     } else if ((fs_ctx->fs_sm == SM_PASSTHROUGH) ||
 476                (fs_ctx->fs_sm == SM_NONE)) {
 477         return lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid);
 478     }
 479     return -1;
 480 }
 481
 482 static int local_utimensat(FsContext *s, const char *path,
 483                        const struct timespec *buf)
 484 {
 485     return utimensat(AT_FDCWD, rpath(s, path), buf, AT_SYMLINK_NOFOLLOW);
 486 }
 487
 488 static int local_remove(FsContext *ctx, const char *path)
 489 {
 490     return remove(rpath(ctx, path));
 491 }
 492
 493 static int local_fsync(FsContext *ctx, int fd)
 494 {
 495     return fsync(fd);
 496 }
 497
 498 static int local_statfs(FsContext *s, const char *path, struct statfs *stbuf)
 499 {
 500    return statfs(rpath(s, path), stbuf);
 501 }
 502
 503 static ssize_t local_lgetxattr(FsContext *ctx, const char *path,
 504                                const char *name, void *value, size_t size)
 505 {
 506     return v9fs_get_xattr(ctx, path, name, value, size);
 507 }
 508
 509 static ssize_t local_llistxattr(FsContext *ctx, const char *path,
 510                                 void *value, size_t size)
 511 {
 512     return v9fs_list_xattr(ctx, path, value, size);
 513 }
 514
 515 static int local_lsetxattr(FsContext *ctx, const char *path, const char *name,
 516                            void *value, size_t size, int flags)
 517 {
 518     return v9fs_set_xattr(ctx, path, name, value, size, flags);
 519 }
 520
 521 static int local_lremovexattr(FsContext *ctx,
 522                               const char *path, const char *name)
 523 {
 524     return v9fs_remove_xattr(ctx, path, name);
 525 }
 526
 527
 528 FileOperations local_ops = {
 529     .lstat = local_lstat,
 530     .readlink = local_readlink,
 531     .close = local_close,
 532     .closedir = local_closedir,
 533     .open = local_open,
 534     .opendir = local_opendir,
 535     .rewinddir = local_rewinddir,
 536     .telldir = local_telldir,
 537     .readdir = local_readdir,
 538     .seekdir = local_seekdir,
 539     .preadv = local_preadv,
 540     .pwritev = local_pwritev,
 541     .chmod = local_chmod,
 542     .mknod = local_mknod,
 543     .mkdir = local_mkdir,
 544     .fstat = local_fstat,
 545     .open2 = local_open2,
 546     .symlink = local_symlink,
 547     .link = local_link,
 548     .truncate = local_truncate,
 549     .rename = local_rename,
 550     .chown = local_chown,
 551     .utimensat = local_utimensat,
 552     .remove = local_remove,
 553     .fsync = local_fsync,
 554     .statfs = local_statfs,
 555     .lgetxattr = local_lgetxattr,
 556     .llistxattr = local_llistxattr,
 557     .lsetxattr = local_lsetxattr,
 558     .lremovexattr = local_lremovexattr,
 559 };