tests/sys/fs/fusefs/utils.cc

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2019 The FreeBSD Foundation
   5  *
   6  * This software was developed by BFF Storage Systems, LLC under sponsorship
   7  * from the FreeBSD Foundation.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  *
  30  * $FreeBSD$
  31  */
  32
  33 extern "C" {
  34 #include <sys/param.h>
  35 #include <sys/mman.h>
  36 #include <sys/module.h>
  37 #include <sys/sysctl.h>
  38 #include <sys/wait.h>
  39
  40 #include <dirent.h>
  41 #include <fcntl.h>
  42 #include <grp.h>
  43 #include <pwd.h>
  44 #include <semaphore.h>
  45 #include <unistd.h>
  46 }
  47
  48 #include <gtest/gtest.h>
  49
  50 #include "mockfs.hh"
  51 #include "utils.hh"
  52
  53 using namespace testing;
  54
  55 /*
  56  * The default max_write is set to this formula in libfuse, though
  57  * individual filesystems can lower it.  The "- 4096" was added in
  58  * commit 154ffe2, with the commit message "fix".
  59  */
  60 const uint32_t libfuse_max_write = 32 * getpagesize() + 0x1000 - 4096;
  61
  62 /* Check that fusefs(4) is accessible and the current user can mount(2) */
  63 void check_environment()
  64 {
  65         const char *devnode = "/dev/fuse";
  66         const char *bsdextended_node = "security.mac.bsdextended.enabled";
  67         int bsdextended_val = 0;
  68         size_t bsdextended_size = sizeof(bsdextended_val);
  69         int bsdextended_found;
  70         const char *usermount_node = "vfs.usermount";
  71         int usermount_val = 0;
  72         size_t usermount_size = sizeof(usermount_val);
  73         if (eaccess(devnode, R_OK | W_OK)) {
  74                 if (errno == ENOENT) {
  75                         GTEST_SKIP() << devnode << " does not exist";
  76                 } else if (errno == EACCES) {
  77                         GTEST_SKIP() << devnode <<
  78                             " is not accessible by the current user";
  79                 } else {
  80                         GTEST_SKIP() << strerror(errno);
  81                 }
  82         }
  83         // mac_bsdextended(4), when enabled, generates many more GETATTR
  84         // operations. The fusefs tests' expectations don't account for those,
  85         // and adding extra code to handle them obfuscates the real purpose of
  86         // the tests.  Better just to skip the fusefs tests if mac_bsdextended
  87         // is enabled.
  88         bsdextended_found = sysctlbyname(bsdextended_node, &bsdextended_val,
  89                                          &bsdextended_size, NULL, 0);
  90         if (bsdextended_found == 0 && bsdextended_val != 0)
  91                 GTEST_SKIP() <<
  92                     "The fusefs tests are incompatible with mac_bsdextended.";
  93         ASSERT_EQ(sysctlbyname(usermount_node, &usermount_val, &usermount_size,
  94                                NULL, 0),
  95                   0);
  96         if (geteuid() != 0 && !usermount_val)
  97                 GTEST_SKIP() << "current user is not allowed to mount";
  98 }
  99
 100 const char *cache_mode_to_s(enum cache_mode cm) {
 101         switch (cm) {
 102         case Uncached:
 103                 return "Uncached";
 104         case Writethrough:
 105                 return "Writethrough";
 106         case Writeback:
 107                 return "Writeback";
 108         case WritebackAsync:
 109                 return "WritebackAsync";
 110         default:
 111                 return "Unknown";
 112         }
 113 }
 114
 115 bool is_unsafe_aio_enabled(void) {
 116         const char *node = "vfs.aio.enable_unsafe";
 117         int val = 0;
 118         size_t size = sizeof(val);
 119
 120         if (sysctlbyname(node, &val, &size, NULL, 0)) {
 121                 perror("sysctlbyname");
 122                 return (false);
 123         }
 124         return (val != 0);
 125 }
 126
 127 class FuseEnv: public Environment {
 128         virtual void SetUp() {
 129         }
 130 };
 131
 132 void FuseTest::SetUp() {
 133         const char *maxbcachebuf_node = "vfs.maxbcachebuf";
 134         const char *maxphys_node = "kern.maxphys";
 135         int val = 0;
 136         size_t size = sizeof(val);
 137
 138         /*
 139          * XXX check_environment should be called from FuseEnv::SetUp, but
 140          * can't due to https://github.com/google/googletest/issues/2189
 141          */
 142         check_environment();
 143         if (IsSkipped())
 144                 return;
 145
 146         ASSERT_EQ(0, sysctlbyname(maxbcachebuf_node, &val, &size, NULL, 0))
 147                 << strerror(errno);
 148         m_maxbcachebuf = val;
 149         ASSERT_EQ(0, sysctlbyname(maxphys_node, &val, &size, NULL, 0))
 150                 << strerror(errno);
 151         m_maxphys = val;
 152         /*
 153          * Set the default max_write to a distinct value from MAXPHYS to catch
 154          * bugs that confuse the two.
 155          */
 156         if (m_maxwrite == 0)
 157                 m_maxwrite = MIN(libfuse_max_write, (uint32_t)m_maxphys / 2);
 158
 159         try {
 160                 m_mock = new MockFS(m_maxreadahead, m_allow_other,
 161                         m_default_permissions, m_push_symlinks_in, m_ro,
 162                         m_pm, m_init_flags, m_kernel_minor_version,
 163                         m_maxwrite, m_async, m_noclusterr, m_time_gran,
 164                         m_nointr);
 165                 /*
 166                  * FUSE_ACCESS is called almost universally.  Expecting it in
 167                  * each test case would be super-annoying.  Instead, set a
 168                  * default expectation for FUSE_ACCESS and return ENOSYS.
 169                  *
 170                  * Individual test cases can override this expectation since
 171                  * googlemock evaluates expectations in LIFO order.
 172                  */
 173                 EXPECT_CALL(*m_mock, process(
 174                         ResultOf([=](auto in) {
 175                                 return (in.header.opcode == FUSE_ACCESS);
 176                         }, Eq(true)),
 177                         _)
 178                 ).Times(AnyNumber())
 179                 .WillRepeatedly(Invoke(ReturnErrno(ENOSYS)));
 180                 /*
 181                  * FUSE_BMAP is called for most test cases that read data.  Set
 182                  * a default expectation and return ENOSYS.
 183                  *
 184                  * Individual test cases can override this expectation since
 185                  * googlemock evaluates expectations in LIFO order.
 186                  */
 187                 EXPECT_CALL(*m_mock, process(
 188                         ResultOf([=](auto in) {
 189                                 return (in.header.opcode == FUSE_BMAP);
 190                         }, Eq(true)),
 191                         _)
 192                 ).Times(AnyNumber())
 193                 .WillRepeatedly(Invoke(ReturnErrno(ENOSYS)));
 194         } catch (std::system_error err) {
 195                 FAIL() << err.what();
 196         }
 197 }
 198
 199 void
 200 FuseTest::expect_access(uint64_t ino, mode_t access_mode, int error)
 201 {
 202         EXPECT_CALL(*m_mock, process(
 203                 ResultOf([=](auto in) {
 204                         return (in.header.opcode == FUSE_ACCESS &&
 205                                 in.header.nodeid == ino &&
 206                                 in.body.access.mask == access_mode);
 207                 }, Eq(true)),
 208                 _)
 209         ).WillOnce(Invoke(ReturnErrno(error)));
 210 }
 211
 212 void
 213 FuseTest::expect_destroy(int error)
 214 {
 215         EXPECT_CALL(*m_mock, process(
 216                 ResultOf([=](auto in) {
 217                         return (in.header.opcode == FUSE_DESTROY);
 218                 }, Eq(true)),
 219                 _)
 220         ).WillOnce(Invoke( ReturnImmediate([&](auto in, auto& out) {
 221                 m_mock->m_quit = true;
 222                 out.header.len = sizeof(out.header);
 223                 out.header.unique = in.header.unique;
 224                 out.header.error = -error;
 225         })));
 226 }
 227
 228 void
 229 FuseTest::expect_flush(uint64_t ino, int times, ProcessMockerT r)
 230 {
 231         EXPECT_CALL(*m_mock, process(
 232                 ResultOf([=](auto in) {
 233                         return (in.header.opcode == FUSE_FLUSH &&
 234                                 in.header.nodeid == ino);
 235                 }, Eq(true)),
 236                 _)
 237         ).Times(times)
 238         .WillRepeatedly(Invoke(r));
 239 }
 240
 241 void
 242 FuseTest::expect_forget(uint64_t ino, uint64_t nlookup, sem_t *sem)
 243 {
 244         EXPECT_CALL(*m_mock, process(
 245                 ResultOf([=](auto in) {
 246                         return (in.header.opcode == FUSE_FORGET &&
 247                                 in.header.nodeid == ino &&
 248                                 in.body.forget.nlookup == nlookup);
 249                 }, Eq(true)),
 250                 _)
 251         ).WillOnce(Invoke([=](auto in __unused, auto &out __unused) {
 252                 if (sem != NULL)
 253                         sem_post(sem);
 254                 /* FUSE_FORGET has no response! */
 255         }));
 256 }
 257
 258 void FuseTest::expect_getattr(uint64_t ino, uint64_t size)
 259 {
 260         EXPECT_CALL(*m_mock, process(
 261                 ResultOf([=](auto in) {
 262                         return (in.header.opcode == FUSE_GETATTR &&
 263                                 in.header.nodeid == ino);
 264                 }, Eq(true)),
 265                 _)
 266         ).WillOnce(Invoke(ReturnImmediate([=](auto i __unused, auto& out) {
 267                 SET_OUT_HEADER_LEN(out, attr);
 268                 out.body.attr.attr.ino = ino;   // Must match nodeid
 269                 out.body.attr.attr.mode = S_IFREG | 0644;
 270                 out.body.attr.attr.size = size;
 271                 out.body.attr.attr_valid = UINT64_MAX;
 272         })));
 273 }
 274
 275 void FuseTest::expect_getxattr(uint64_t ino, const char *attr, ProcessMockerT r)
 276 {
 277         EXPECT_CALL(*m_mock, process(
 278                 ResultOf([=](auto in) {
 279                         const char *a = (const char*)in.body.bytes +
 280                                 sizeof(fuse_getxattr_in);
 281                         return (in.header.opcode == FUSE_GETXATTR &&
 282                                 in.header.nodeid == ino &&
 283                                 0 == strcmp(attr, a));
 284                 }, Eq(true)),
 285                 _)
 286         ).WillOnce(Invoke(r));
 287 }
 288
 289 void FuseTest::expect_lookup(const char *relpath, uint64_t ino, mode_t mode,
 290         uint64_t size, int times, uint64_t attr_valid, uid_t uid, gid_t gid)
 291 {
 292         EXPECT_LOOKUP(FUSE_ROOT_ID, relpath)
 293         .Times(times)
 294         .WillRepeatedly(Invoke(
 295                 ReturnImmediate([=](auto in __unused, auto& out) {
 296                 SET_OUT_HEADER_LEN(out, entry);
 297                 out.body.entry.attr.mode = mode;
 298                 out.body.entry.nodeid = ino;
 299                 out.body.entry.attr.nlink = 1;
 300                 out.body.entry.attr_valid = attr_valid;
 301                 out.body.entry.attr.size = size;
 302                 out.body.entry.attr.uid = uid;
 303                 out.body.entry.attr.gid = gid;
 304         })));
 305 }
 306
 307 void FuseTest::expect_lookup_7_8(const char *relpath, uint64_t ino, mode_t mode,
 308         uint64_t size, int times, uint64_t attr_valid, uid_t uid, gid_t gid)
 309 {
 310         EXPECT_LOOKUP(FUSE_ROOT_ID, relpath)
 311         .Times(times)
 312         .WillRepeatedly(Invoke(
 313                 ReturnImmediate([=](auto in __unused, auto& out) {
 314                 SET_OUT_HEADER_LEN(out, entry_7_8);
 315                 out.body.entry.attr.mode = mode;
 316                 out.body.entry.nodeid = ino;
 317                 out.body.entry.attr.nlink = 1;
 318                 out.body.entry.attr_valid = attr_valid;
 319                 out.body.entry.attr.size = size;
 320                 out.body.entry.attr.uid = uid;
 321                 out.body.entry.attr.gid = gid;
 322         })));
 323 }
 324
 325 void FuseTest::expect_open(uint64_t ino, uint32_t flags, int times)
 326 {
 327         EXPECT_CALL(*m_mock, process(
 328                 ResultOf([=](auto in) {
 329                         return (in.header.opcode == FUSE_OPEN &&
 330                                 in.header.nodeid == ino);
 331                 }, Eq(true)),
 332                 _)
 333         ).Times(times)
 334         .WillRepeatedly(Invoke(
 335                 ReturnImmediate([=](auto in __unused, auto& out) {
 336                 out.header.len = sizeof(out.header);
 337                 SET_OUT_HEADER_LEN(out, open);
 338                 out.body.open.fh = FH;
 339                 out.body.open.open_flags = flags;
 340         })));
 341 }
 342
 343 void FuseTest::expect_opendir(uint64_t ino)
 344 {
 345         /* opendir(3) calls fstatfs */
 346         EXPECT_CALL(*m_mock, process(
 347                 ResultOf([](auto in) {
 348                         return (in.header.opcode == FUSE_STATFS);
 349                 }, Eq(true)),
 350                 _)
 351         ).WillRepeatedly(Invoke(
 352         ReturnImmediate([=](auto i __unused, auto& out) {
 353                 SET_OUT_HEADER_LEN(out, statfs);
 354         })));
 355
 356         EXPECT_CALL(*m_mock, process(
 357                 ResultOf([=](auto in) {
 358                         return (in.header.opcode == FUSE_OPENDIR &&
 359                                 in.header.nodeid == ino);
 360                 }, Eq(true)),
 361                 _)
 362         ).WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
 363                 out.header.len = sizeof(out.header);
 364                 SET_OUT_HEADER_LEN(out, open);
 365                 out.body.open.fh = FH;
 366         })));
 367 }
 368
 369 void FuseTest::expect_read(uint64_t ino, uint64_t offset, uint64_t isize,
 370         uint64_t osize, const void *contents, int flags)
 371 {
 372         EXPECT_CALL(*m_mock, process(
 373                 ResultOf([=](auto in) {
 374                         return (in.header.opcode == FUSE_READ &&
 375                                 in.header.nodeid == ino &&
 376                                 in.body.read.fh == FH &&
 377                                 in.body.read.offset == offset &&
 378                                 in.body.read.size == isize &&
 379                                 (flags == -1 ?
 380                                         (in.body.read.flags == O_RDONLY ||
 381                                          in.body.read.flags == O_RDWR)
 382                                 : in.body.read.flags == (uint32_t)flags));
 383                 }, Eq(true)),
 384                 _)
 385         ).WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
 386                 out.header.len = sizeof(struct fuse_out_header) + osize;
 387                 memmove(out.body.bytes, contents, osize);
 388         }))).RetiresOnSaturation();
 389 }
 390
 391 void FuseTest::expect_readdir(uint64_t ino, uint64_t off,
 392         std::vector<struct dirent> &ents)
 393 {
 394         EXPECT_CALL(*m_mock, process(
 395                 ResultOf([=](auto in) {
 396                         return (in.header.opcode == FUSE_READDIR &&
 397                                 in.header.nodeid == ino &&
 398                                 in.body.readdir.fh == FH &&
 399                                 in.body.readdir.offset == off);
 400                 }, Eq(true)),
 401                 _)
 402         ).WillRepeatedly(Invoke(ReturnImmediate([=](auto in, auto& out) {
 403                 struct fuse_dirent *fde = (struct fuse_dirent*)&(out.body);
 404                 int i = 0;
 405
 406                 out.header.error = 0;
 407                 out.header.len = 0;
 408
 409                 for (const auto& it: ents) {
 410                         size_t entlen, entsize;
 411
 412                         fde->ino = it.d_fileno;
 413                         fde->off = it.d_off;
 414                         fde->type = it.d_type;
 415                         fde->namelen = it.d_namlen;
 416                         strncpy(fde->name, it.d_name, it.d_namlen);
 417                         entlen = FUSE_NAME_OFFSET + fde->namelen;
 418                         entsize = FUSE_DIRENT_SIZE(fde);
 419                         /*
 420                          * The FUSE protocol does not require zeroing out the
 421                          * unused portion of the name.  But it's a good
 422                          * practice to prevent information disclosure to the
 423                          * FUSE client, even though the client is usually the
 424                          * kernel
 425                          */
 426                         memset(fde->name + fde->namelen, 0, entsize - entlen);
 427                         if (out.header.len + entsize > in.body.read.size) {
 428                                 printf("Overflow in readdir expectation: i=%d\n"
 429                                         , i);
 430                                 break;
 431                         }
 432                         out.header.len += entsize;
 433                         fde = (struct fuse_dirent*)
 434                                 ((intmax_t*)fde + entsize / sizeof(intmax_t));
 435                         i++;
 436                 }
 437                 out.header.len += sizeof(out.header);
 438         })));
 439
 440 }
 441 void FuseTest::expect_release(uint64_t ino, uint64_t fh)
 442 {
 443         EXPECT_CALL(*m_mock, process(
 444                 ResultOf([=](auto in) {
 445                         return (in.header.opcode == FUSE_RELEASE &&
 446                                 in.header.nodeid == ino &&
 447                                 in.body.release.fh == fh);
 448                 }, Eq(true)),
 449                 _)
 450         ).WillOnce(Invoke(ReturnErrno(0)));
 451 }
 452
 453 void FuseTest::expect_releasedir(uint64_t ino, ProcessMockerT r)
 454 {
 455         EXPECT_CALL(*m_mock, process(
 456                 ResultOf([=](auto in) {
 457                         return (in.header.opcode == FUSE_RELEASEDIR &&
 458                                 in.header.nodeid == ino &&
 459                                 in.body.release.fh == FH);
 460                 }, Eq(true)),
 461                 _)
 462         ).WillOnce(Invoke(r));
 463 }
 464
 465 void FuseTest::expect_unlink(uint64_t parent, const char *path, int error)
 466 {
 467         EXPECT_CALL(*m_mock, process(
 468                 ResultOf([=](auto in) {
 469                         return (in.header.opcode == FUSE_UNLINK &&
 470                                 0 == strcmp(path, in.body.unlink) &&
 471                                 in.header.nodeid == parent);
 472                 }, Eq(true)),
 473                 _)
 474         ).WillOnce(Invoke(ReturnErrno(error)));
 475 }
 476
 477 void FuseTest::expect_write(uint64_t ino, uint64_t offset, uint64_t isize,
 478         uint64_t osize, uint32_t flags_set, uint32_t flags_unset,
 479         const void *contents)
 480 {
 481         EXPECT_CALL(*m_mock, process(
 482                 ResultOf([=](auto in) {
 483                         const char *buf = (const char*)in.body.bytes +
 484                                 sizeof(struct fuse_write_in);
 485                         bool pid_ok;
 486                         uint32_t wf = in.body.write.write_flags;
 487
 488                         if (wf & FUSE_WRITE_CACHE)
 489                                 pid_ok = true;
 490                         else
 491                                 pid_ok = (pid_t)in.header.pid == getpid();
 492
 493                         return (in.header.opcode == FUSE_WRITE &&
 494                                 in.header.nodeid == ino &&
 495                                 in.body.write.fh == FH &&
 496                                 in.body.write.offset == offset  &&
 497                                 in.body.write.size == isize &&
 498                                 pid_ok &&
 499                                 (wf & flags_set) == flags_set &&
 500                                 (wf & flags_unset) == 0 &&
 501                                 (in.body.write.flags == O_WRONLY ||
 502                                  in.body.write.flags == O_RDWR) &&
 503                                 0 == bcmp(buf, contents, isize));
 504                 }, Eq(true)),
 505                 _)
 506         ).WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
 507                 SET_OUT_HEADER_LEN(out, write);
 508                 out.body.write.size = osize;
 509         })));
 510 }
 511
 512 void FuseTest::expect_write_7_8(uint64_t ino, uint64_t offset, uint64_t isize,
 513         uint64_t osize, const void *contents)
 514 {
 515         EXPECT_CALL(*m_mock, process(
 516                 ResultOf([=](auto in) {
 517                         const char *buf = (const char*)in.body.bytes +
 518                                 FUSE_COMPAT_WRITE_IN_SIZE;
 519                         bool pid_ok = (pid_t)in.header.pid == getpid();
 520                         return (in.header.opcode == FUSE_WRITE &&
 521                                 in.header.nodeid == ino &&
 522                                 in.body.write.fh == FH &&
 523                                 in.body.write.offset == offset  &&
 524                                 in.body.write.size == isize &&
 525                                 pid_ok &&
 526                                 0 == bcmp(buf, contents, isize));
 527                 }, Eq(true)),
 528                 _)
 529         ).WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
 530                 SET_OUT_HEADER_LEN(out, write);
 531                 out.body.write.size = osize;
 532         })));
 533 }
 534
 535 void
 536 get_unprivileged_id(uid_t *uid, gid_t *gid)
 537 {
 538         struct passwd *pw;
 539         struct group *gr;
 540
 541         /*
 542          * First try "tests", Kyua's default unprivileged user.  XXX after
 543          * GoogleTest gains a proper Kyua wrapper, get this with the Kyua API
 544          */
 545         pw = getpwnam("tests");
 546         if (pw == NULL) {
 547                 /* Fall back to "nobody" */
 548                 pw = getpwnam("nobody");
 549         }
 550         if (pw == NULL)
 551                 GTEST_SKIP() << "Test requires an unprivileged user";
 552         /* Use group "nobody", which is Kyua's default unprivileged group */
 553         gr = getgrnam("nobody");
 554         if (gr == NULL)
 555                 GTEST_SKIP() << "Test requires an unprivileged group";
 556         *uid = pw->pw_uid;
 557         *gid = gr->gr_gid;
 558 }
 559
 560 void
 561 FuseTest::fork(bool drop_privs, int *child_status,
 562         std::function<void()> parent_func,
 563         std::function<int()> child_func)
 564 {
 565         sem_t *sem;
 566         int mprot = PROT_READ | PROT_WRITE;
 567         int mflags = MAP_ANON | MAP_SHARED;
 568         pid_t child;
 569         uid_t uid;
 570         gid_t gid;
 571
 572         if (drop_privs) {
 573                 get_unprivileged_id(&uid, &gid);
 574                 if (IsSkipped())
 575                         return;
 576         }
 577
 578         sem = (sem_t*)mmap(NULL, sizeof(*sem), mprot, mflags, -1, 0);
 579         ASSERT_NE(MAP_FAILED, sem) << strerror(errno);
 580         ASSERT_EQ(0, sem_init(sem, 1, 0)) << strerror(errno);
 581
 582         if ((child = ::fork()) == 0) {
 583                 /* In child */
 584                 int err = 0;
 585
 586                 if (sem_wait(sem)) {
 587                         perror("sem_wait");
 588                         err = 1;
 589                         goto out;
 590                 }
 591
 592                 if (drop_privs && 0 != setegid(gid)) {
 593                         perror("setegid");
 594                         err = 1;
 595                         goto out;
 596                 }
 597                 if (drop_privs && 0 != setreuid(-1, uid)) {
 598                         perror("setreuid");
 599                         err = 1;
 600                         goto out;
 601                 }
 602                 err = child_func();
 603
 604 out:
 605                 sem_destroy(sem);
 606                 _exit(err);
 607         } else if (child > 0) {
 608                 /*
 609                  * In parent.  Cleanup must happen here, because it's still
 610                  * privileged.
 611                  */
 612                 m_mock->m_child_pid = child;
 613                 ASSERT_NO_FATAL_FAILURE(parent_func());
 614
 615                 /* Signal the child process to go */
 616                 ASSERT_EQ(0, sem_post(sem)) << strerror(errno);
 617
 618                 ASSERT_LE(0, wait(child_status)) << strerror(errno);
 619         } else {
 620                 FAIL() << strerror(errno);
 621         }
 622         munmap(sem, sizeof(*sem));
 623         return;
 624 }
 625
 626 static void usage(char* progname) {
 627         fprintf(stderr, "Usage: %s [-v]\n\t-v increase verbosity\n", progname);
 628         exit(2);
 629 }
 630
 631 int main(int argc, char **argv) {
 632         int ch;
 633         FuseEnv *fuse_env = new FuseEnv;
 634
 635         InitGoogleTest(&argc, argv);
 636         AddGlobalTestEnvironment(fuse_env);
 637
 638         while ((ch = getopt(argc, argv, "v")) != -1) {
 639                 switch (ch) {
 640                         case 'v':
 641                                 verbosity++;
 642                                 break;
 643                         default:
 644                                 usage(argv[0]);
 645                                 break;
 646                 }
 647         }
 648
 649         return (RUN_ALL_TESTS());
 650 }