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 <arpa/inet.h>
  16 #include <pwd.h>
  17 #include <grp.h>
  18 #include <sys/socket.h>
  19 #include <sys/un.h>
  20 #include <attr/xattr.h>
  21
  22 static const char *rpath(FsContext *ctx, const char *path)
  23 {
  24     /* FIXME: so wrong... */
  25     static char buffer[4096];
  26     snprintf(buffer, sizeof(buffer), "%s/%s", ctx->fs_root, path);
  27     return buffer;
  28 }
  29
  30
  31 static int local_lstat(FsContext *fs_ctx, const char *path, struct stat *stbuf)
  32 {
  33     int err;
  34     err =  lstat(rpath(fs_ctx, path), stbuf);
  35     if (err) {
  36         return err;
  37     }
  38     if (fs_ctx->fs_sm == SM_MAPPED) {
  39         /* Actual credentials are part of extended attrs */
  40         uid_t tmp_uid;
  41         gid_t tmp_gid;
  42         mode_t tmp_mode;
  43         dev_t tmp_dev;
  44         if (getxattr(rpath(fs_ctx, path), "user.virtfs.uid", &tmp_uid,
  45                     sizeof(uid_t)) > 0) {
  46             stbuf->st_uid = tmp_uid;
  47         }
  48         if (getxattr(rpath(fs_ctx, path), "user.virtfs.gid", &tmp_gid,
  49                     sizeof(gid_t)) > 0) {
  50             stbuf->st_gid = tmp_gid;
  51         }
  52         if (getxattr(rpath(fs_ctx, path), "user.virtfs.mode", &tmp_mode,
  53                     sizeof(mode_t)) > 0) {
  54             stbuf->st_mode = tmp_mode;
  55         }
  56         if (getxattr(rpath(fs_ctx, path), "user.virtfs.rdev", &tmp_dev,
  57                         sizeof(dev_t)) > 0) {
  58                 stbuf->st_rdev = tmp_dev;
  59         }
  60     }
  61     return err;
  62 }
  63
  64 static int local_set_xattr(const char *path, FsCred *credp)
  65 {
  66     int err;
  67     if (credp->fc_uid != -1) {
  68         err = setxattr(path, "user.virtfs.uid", &credp->fc_uid, sizeof(uid_t),
  69                 0);
  70         if (err) {
  71             return err;
  72         }
  73     }
  74     if (credp->fc_gid != -1) {
  75         err = setxattr(path, "user.virtfs.gid", &credp->fc_gid, sizeof(gid_t),
  76                 0);
  77         if (err) {
  78             return err;
  79         }
  80     }
  81     if (credp->fc_mode != -1) {
  82         err = setxattr(path, "user.virtfs.mode", &credp->fc_mode,
  83                 sizeof(mode_t), 0);
  84         if (err) {
  85             return err;
  86         }
  87     }
  88     if (credp->fc_rdev != -1) {
  89         err = setxattr(path, "user.virtfs.rdev", &credp->fc_rdev,
  90                 sizeof(dev_t), 0);
  91         if (err) {
  92             return err;
  93         }
  94     }
  95     return 0;
  96 }
  97
  98 static int local_post_create_passthrough(FsContext *fs_ctx, const char *path,
  99         FsCred *credp)
 100 {
 101     if (chmod(rpath(fs_ctx, path), credp->fc_mode & 07777) < 0) {
 102         return -1;
 103     }
 104     if (chown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid) < 0) {
 105         return -1;
 106     }
 107     return 0;
 108 }
 109
 110 static ssize_t local_readlink(FsContext *fs_ctx, const char *path,
 111         char *buf, size_t bufsz)
 112 {
 113     ssize_t tsize = -1;
 114     if (fs_ctx->fs_sm == SM_MAPPED) {
 115         int fd;
 116         fd = open(rpath(fs_ctx, path), O_RDONLY);
 117         if (fd == -1) {
 118             return -1;
 119         }
 120         do {
 121             tsize = read(fd, (void *)buf, bufsz);
 122         } while (tsize == -1 && errno == EINTR);
 123         close(fd);
 124         return tsize;
 125     } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
 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_readv(FsContext *ctx, int fd, const struct iovec *iov,
 172                             int iovcnt)
 173 {
 174     return readv(fd, iov, iovcnt);
 175 }
 176
 177 static off_t local_lseek(FsContext *ctx, int fd, off_t offset, int whence)
 178 {
 179     return lseek(fd, offset, whence);
 180 }
 181
 182 static ssize_t local_writev(FsContext *ctx, int fd, const struct iovec *iov,
 183                             int iovcnt)
 184 {
 185     return writev(fd, iov, iovcnt);
 186 }
 187
 188 static int local_chmod(FsContext *fs_ctx, const char *path, FsCred *credp)
 189 {
 190     if (fs_ctx->fs_sm == SM_MAPPED) {
 191         return local_set_xattr(rpath(fs_ctx, path), credp);
 192     } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
 193         return chmod(rpath(fs_ctx, path), credp->fc_mode);
 194     }
 195     return -1;
 196 }
 197
 198 static int local_mknod(FsContext *fs_ctx, const char *path, FsCred *credp)
 199 {
 200     int err = -1;
 201     int serrno = 0;
 202
 203     /* Determine the security model */
 204     if (fs_ctx->fs_sm == SM_MAPPED) {
 205         err = mknod(rpath(fs_ctx, path), SM_LOCAL_MODE_BITS|S_IFREG, 0);
 206         if (err == -1) {
 207             return err;
 208         }
 209         local_set_xattr(rpath(fs_ctx, path), credp);
 210         if (err == -1) {
 211             serrno = errno;
 212             goto err_end;
 213         }
 214     } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
 215         err = mknod(rpath(fs_ctx, path), credp->fc_mode, credp->fc_rdev);
 216         if (err == -1) {
 217             return err;
 218         }
 219         err = local_post_create_passthrough(fs_ctx, path, credp);
 220         if (err == -1) {
 221             serrno = errno;
 222             goto err_end;
 223         }
 224     }
 225     return err;
 226
 227 err_end:
 228     remove(rpath(fs_ctx, path));
 229     errno = serrno;
 230     return err;
 231 }
 232
 233 static int local_mksock(FsContext *ctx2, const char *path)
 234 {
 235     struct sockaddr_un addr;
 236     int s;
 237
 238     addr.sun_family = AF_UNIX;
 239     snprintf(addr.sun_path, 108, "%s", rpath(ctx2, path));
 240
 241     s = socket(PF_UNIX, SOCK_STREAM, 0);
 242     if (s == -1) {
 243         return -1;
 244     }
 245
 246     if (bind(s, (struct sockaddr *)&addr, sizeof(addr))) {
 247         close(s);
 248         return -1;
 249     }
 250
 251     close(s);
 252     return 0;
 253 }
 254
 255 static int local_mkdir(FsContext *fs_ctx, const char *path, FsCred *credp)
 256 {
 257     int err = -1;
 258     int serrno = 0;
 259
 260     /* Determine the security model */
 261     if (fs_ctx->fs_sm == SM_MAPPED) {
 262         err = mkdir(rpath(fs_ctx, path), SM_LOCAL_DIR_MODE_BITS);
 263         if (err == -1) {
 264             return err;
 265         }
 266         credp->fc_mode = credp->fc_mode|S_IFDIR;
 267         err = local_set_xattr(rpath(fs_ctx, path), credp);
 268         if (err == -1) {
 269             serrno = errno;
 270             goto err_end;
 271         }
 272     } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
 273         err = mkdir(rpath(fs_ctx, path), credp->fc_mode);
 274         if (err == -1) {
 275             return err;
 276         }
 277         err = local_post_create_passthrough(fs_ctx, path, credp);
 278         if (err == -1) {
 279             serrno = errno;
 280             goto err_end;
 281         }
 282     }
 283     return err;
 284
 285 err_end:
 286     remove(rpath(fs_ctx, path));
 287     errno = serrno;
 288     return err;
 289 }
 290
 291 static int local_fstat(FsContext *fs_ctx, int fd, struct stat *stbuf)
 292 {
 293     int err;
 294     err = fstat(fd, stbuf);
 295     if (err) {
 296         return err;
 297     }
 298     if (fs_ctx->fs_sm == SM_MAPPED) {
 299         /* Actual credentials are part of extended attrs */
 300         uid_t tmp_uid;
 301         gid_t tmp_gid;
 302         mode_t tmp_mode;
 303         dev_t tmp_dev;
 304
 305         if (fgetxattr(fd, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) {
 306             stbuf->st_uid = tmp_uid;
 307         }
 308         if (fgetxattr(fd, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) {
 309             stbuf->st_gid = tmp_gid;
 310         }
 311         if (fgetxattr(fd, "user.virtfs.mode", &tmp_mode, sizeof(mode_t)) > 0) {
 312             stbuf->st_mode = tmp_mode;
 313         }
 314         if (fgetxattr(fd, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) {
 315                 stbuf->st_rdev = tmp_dev;
 316         }
 317     }
 318     return err;
 319 }
 320
 321 static int local_open2(FsContext *fs_ctx, const char *path, int flags,
 322         FsCred *credp)
 323 {
 324     int fd = -1;
 325     int err = -1;
 326     int serrno = 0;
 327
 328     /* Determine the security model */
 329     if (fs_ctx->fs_sm == SM_MAPPED) {
 330         fd = open(rpath(fs_ctx, path), flags, SM_LOCAL_MODE_BITS);
 331         if (fd == -1) {
 332             return fd;
 333         }
 334         credp->fc_mode = credp->fc_mode|S_IFREG;
 335         /* Set cleint credentials in xattr */
 336         err = local_set_xattr(rpath(fs_ctx, path), credp);
 337         if (err == -1) {
 338             serrno = errno;
 339             goto err_end;
 340         }
 341     } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
 342         fd = open(rpath(fs_ctx, path), flags, credp->fc_mode);
 343         if (fd == -1) {
 344             return fd;
 345         }
 346         err = local_post_create_passthrough(fs_ctx, path, credp);
 347         if (err == -1) {
 348             serrno = errno;
 349             goto err_end;
 350         }
 351     }
 352     return fd;
 353
 354 err_end:
 355     close(fd);
 356     remove(rpath(fs_ctx, path));
 357     errno = serrno;
 358     return err;
 359 }
 360
 361
 362 static int local_symlink(FsContext *fs_ctx, const char *oldpath,
 363         const char *newpath, FsCred *credp)
 364 {
 365     int err = -1;
 366     int serrno = 0;
 367
 368     /* Determine the security model */
 369     if (fs_ctx->fs_sm == SM_MAPPED) {
 370         int fd;
 371         ssize_t oldpath_size, write_size;
 372         fd = open(rpath(fs_ctx, newpath), O_CREAT|O_EXCL|O_RDWR,
 373                 SM_LOCAL_MODE_BITS);
 374         if (fd == -1) {
 375             return fd;
 376         }
 377         /* Write the oldpath (target) to the file. */
 378         oldpath_size = strlen(oldpath) + 1;
 379         do {
 380             write_size = write(fd, (void *)oldpath, oldpath_size);
 381         } while (write_size == -1 && errno == EINTR);
 382
 383         if (write_size != oldpath_size) {
 384             serrno = errno;
 385             close(fd);
 386             err = -1;
 387             goto err_end;
 388         }
 389         close(fd);
 390         /* Set cleint credentials in symlink's xattr */
 391         credp->fc_mode = credp->fc_mode|S_IFLNK;
 392         err = local_set_xattr(rpath(fs_ctx, newpath), credp);
 393         if (err == -1) {
 394             serrno = errno;
 395             goto err_end;
 396         }
 397     } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
 398         err = symlink(oldpath, rpath(fs_ctx, newpath));
 399         if (err) {
 400             return err;
 401         }
 402         err = lchown(rpath(fs_ctx, newpath), credp->fc_uid, credp->fc_gid);
 403         if (err == -1) {
 404             serrno = errno;
 405             goto err_end;
 406         }
 407     }
 408     return err;
 409
 410 err_end:
 411     remove(rpath(fs_ctx, newpath));
 412     errno = serrno;
 413     return err;
 414 }
 415
 416 static int local_link(FsContext *ctx, const char *oldpath, const char *newpath)
 417 {
 418     char *tmp = qemu_strdup(rpath(ctx, oldpath));
 419     int err, serrno = 0;
 420
 421     if (tmp == NULL) {
 422         return -ENOMEM;
 423     }
 424
 425     err = link(tmp, rpath(ctx, newpath));
 426     if (err == -1) {
 427         serrno = errno;
 428     }
 429
 430     qemu_free(tmp);
 431
 432     if (err == -1) {
 433         errno = serrno;
 434     }
 435
 436     return err;
 437 }
 438
 439 static int local_truncate(FsContext *ctx, const char *path, off_t size)
 440 {
 441     return truncate(rpath(ctx, path), size);
 442 }
 443
 444 static int local_rename(FsContext *ctx, const char *oldpath,
 445                         const char *newpath)
 446 {
 447     char *tmp;
 448     int err;
 449
 450     tmp = qemu_strdup(rpath(ctx, oldpath));
 451     if (tmp == NULL) {
 452         return -1;
 453     }
 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 (fs_ctx->fs_sm == SM_MAPPED) {
 471         return local_set_xattr(rpath(fs_ctx, path), credp);
 472     } else if (fs_ctx->fs_sm == SM_PASSTHROUGH) {
 473         return lchown(rpath(fs_ctx, path), credp->fc_uid, credp->fc_gid);
 474     }
 475     return -1;
 476 }
 477
 478 static int local_utime(FsContext *ctx, const char *path,
 479                         const struct utimbuf *buf)
 480 {
 481     return utime(rpath(ctx, path), buf);
 482 }
 483
 484 static int local_remove(FsContext *ctx, const char *path)
 485 {
 486     return remove(rpath(ctx, path));
 487 }
 488
 489 static int local_fsync(FsContext *ctx, int fd)
 490 {
 491     return fsync(fd);
 492 }
 493
 494 FileOperations local_ops = {
 495     .lstat = local_lstat,
 496     .readlink = local_readlink,
 497     .close = local_close,
 498     .closedir = local_closedir,
 499     .open = local_open,
 500     .opendir = local_opendir,
 501     .rewinddir = local_rewinddir,
 502     .telldir = local_telldir,
 503     .readdir = local_readdir,
 504     .seekdir = local_seekdir,
 505     .readv = local_readv,
 506     .lseek = local_lseek,
 507     .writev = local_writev,
 508     .chmod = local_chmod,
 509     .mknod = local_mknod,
 510     .mksock = local_mksock,
 511     .mkdir = local_mkdir,
 512     .fstat = local_fstat,
 513     .open2 = local_open2,
 514     .symlink = local_symlink,
 515     .link = local_link,
 516     .truncate = local_truncate,
 517     .rename = local_rename,
 518     .chown = local_chown,
 519     .utime = local_utime,
 520     .remove = local_remove,
 521     .fsync = local_fsync,
 522 };