tests/test-fcntl.c

   1 /* Test of fcntl(2).
   2    Copyright (C) 2009-2024 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Eric Blake <ebb9@byu.net>, 2009.  */
  18
  19 #include <config.h>
  20
  21 /* Specification.  */
  22 #include <fcntl.h>
  23
  24 #include "signature.h"
  25 SIGNATURE_CHECK (fcntl, int, (int, int, ...));
  26
  27 /* Helpers.  */
  28 #include <errno.h>
  29 #include <stdarg.h>
  30 #include <unistd.h>
  31
  32 #if defined _WIN32 && ! defined __CYGWIN__
  33 /* Get declarations of the native Windows API functions.  */
  34 # define WIN32_LEAN_AND_MEAN
  35 # include <windows.h>
  36 /* Get _get_osfhandle.  */
  37 # if GNULIB_MSVC_NOTHROW
  38 #  include "msvc-nothrow.h"
  39 # else
  40 #  include <io.h>
  41 # endif
  42 #endif
  43
  44 #include "binary-io.h"
  45 #include "macros.h"
  46
  47 /* Tell GCC not to warn about the specific edge cases tested here.  */
  48 #if __GNUC__ >= 13
  49 # pragma GCC diagnostic ignored "-Wanalyzer-fd-leak"
  50 # pragma GCC diagnostic ignored "-Wanalyzer-va-arg-type-mismatch"
  51 #endif
  52
  53 #if !O_BINARY
  54 # define set_binary_mode my_set_binary_mode
  55 static int
  56 set_binary_mode (_GL_UNUSED int fd, _GL_UNUSED int mode)
  57 {
  58   return 0;
  59 }
  60 #endif
  61
  62 /* Return true if FD is open.  */
  63 static bool
  64 is_open (int fd)
  65 {
  66 #if defined _WIN32 && ! defined __CYGWIN__
  67   /* On native Windows, the initial state of unassigned standard file
  68      descriptors is that they are open but point to an
  69      INVALID_HANDLE_VALUE, and there is no fcntl.  */
  70   return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
  71 #else
  72 # ifndef F_GETFL
  73 #  error Please port fcntl to your platform
  74 # endif
  75   return 0 <= fcntl (fd, F_GETFL);
  76 #endif
  77 }
  78
  79 /* Return true if FD is open and inheritable across exec/spawn.  */
  80 static bool
  81 is_inheritable (int fd)
  82 {
  83 #if defined _WIN32 && ! defined __CYGWIN__
  84   /* On native Windows, the initial state of unassigned standard file
  85      descriptors is that they are open but point to an
  86      INVALID_HANDLE_VALUE, and there is no fcntl.  */
  87   HANDLE h = (HANDLE) _get_osfhandle (fd);
  88   DWORD flags;
  89   if (h == INVALID_HANDLE_VALUE || GetHandleInformation (h, &flags) == 0)
  90     return false;
  91   return (flags & HANDLE_FLAG_INHERIT) != 0;
  92 #else
  93 # ifndef F_GETFD
  94 #  error Please port fcntl to your platform
  95 # endif
  96   int i = fcntl (fd, F_GETFD);
  97   return 0 <= i && (i & FD_CLOEXEC) == 0;
  98 #endif
  99 }
 100
 101 /* Return non-zero if FD is open in the given MODE, which is either
 102    O_TEXT or O_BINARY.  */
 103 static bool
 104 is_mode (int fd, int mode)
 105 {
 106   int value = set_binary_mode (fd, O_BINARY);
 107   set_binary_mode (fd, value);
 108   return mode == value;
 109 }
 110
 111 /* Since native fcntl can have more supported operations than our
 112    replacement is aware of, and since various operations assign
 113    different types to the vararg argument, a wrapper around fcntl must
 114    be able to pass a vararg of unknown type on through to the original
 115    fcntl.  Make sure that this works properly: func1 behaves like the
 116    original fcntl interpreting the vararg as an int or a pointer to a
 117    struct, and func2 behaves like rpl_fcntl that doesn't know what
 118    type to forward.  */
 119 struct dummy_struct
 120 {
 121   long filler;
 122   int value;
 123 };
 124 static int
 125 func1 (int a, ...)
 126 {
 127   va_list arg;
 128   int i;
 129   va_start (arg, a);
 130   if (a < 4)
 131     i = va_arg (arg, int);
 132   else
 133     {
 134       struct dummy_struct *s = va_arg (arg, struct dummy_struct *);
 135       i = s->value;
 136     }
 137   va_end (arg);
 138   return i;
 139 }
 140 static int
 141 func2 (int a, ...)
 142 {
 143   va_list arg;
 144   void *p;
 145   va_start (arg, a);
 146   p = va_arg (arg, void *);
 147   va_end (arg);
 148   return func1 (a, p);
 149 }
 150
 151 /* Ensure that all supported fcntl actions are distinct, and
 152    usable in preprocessor expressions.  */
 153 static void
 154 check_flags (void)
 155 {
 156   switch (0)
 157     {
 158     case F_DUPFD:
 159 #if F_DUPFD
 160 #endif
 161
 162     case F_DUPFD_CLOEXEC:
 163 #if F_DUPFD_CLOEXEC
 164 #endif
 165
 166     case F_GETFD:
 167 #if F_GETFD
 168 #endif
 169
 170 #ifdef F_SETFD
 171     case F_SETFD:
 172 # if F_SETFD
 173 # endif
 174 #endif
 175
 176 #ifdef F_GETFL
 177     case F_GETFL:
 178 # if F_GETFL
 179 # endif
 180 #endif
 181
 182 #ifdef F_SETFL
 183     case F_SETFL:
 184 # if F_SETFL
 185 # endif
 186 #endif
 187
 188 #ifdef F_GETOWN
 189     case F_GETOWN:
 190 # if F_GETOWN
 191 # endif
 192 #endif
 193
 194 #ifdef F_SETOWN
 195     case F_SETOWN:
 196 # if F_SETOWN
 197 # endif
 198 #endif
 199
 200 #ifdef F_GETLK
 201     case F_GETLK:
 202 # if F_GETLK
 203 # endif
 204 #endif
 205
 206 #ifdef F_SETLK
 207     case F_SETLK:
 208 # if F_SETLK
 209 # endif
 210 #endif
 211
 212 #ifdef F_SETLKW
 213     case F_SETLKW:
 214 # if F_SETLKW
 215 # endif
 216 #endif
 217
 218     default:
 219       ;
 220     }
 221 }
 222
 223 int
 224 main (int argc, _GL_UNUSED char *argv[])
 225 {
 226   if (argc > 1)
 227     /* child process */
 228     return (is_open (10) ? 42 : 0);
 229
 230   const char *file = "test-fcntl.tmp";
 231   int fd;
 232   int bad_fd = getdtablesize ();
 233
 234   /* Sanity check that rpl_fcntl is likely to work.  */
 235   ASSERT (func2 (1, 2) == 2);
 236   ASSERT (func2 (2, -2) == -2);
 237   ASSERT (func2 (3, 0x80000000) == 0x80000000);
 238   {
 239     struct dummy_struct s = { 0L, 4 };
 240     ASSERT (func2 (4, &s) == 4);
 241   }
 242   check_flags ();
 243
 244   /* Assume std descriptors were provided by invoker, and ignore fds
 245      that might have been inherited.  */
 246   fd = creat (file, 0600);
 247   ASSERT (STDERR_FILENO < fd);
 248   close (fd + 1);
 249   close (fd + 2);
 250
 251   /* For F_DUPFD*, the source must be valid.  */
 252   errno = 0;
 253   ASSERT (fcntl (-1, F_DUPFD, 0) == -1);
 254   ASSERT (errno == EBADF);
 255   errno = 0;
 256   ASSERT (fcntl (fd + 1, F_DUPFD, 0) == -1);
 257   ASSERT (errno == EBADF);
 258   errno = 0;
 259   ASSERT (fcntl (bad_fd, F_DUPFD, 0) == -1);
 260   ASSERT (errno == EBADF);
 261   errno = 0;
 262   ASSERT (fcntl (-1, F_DUPFD_CLOEXEC, 0) == -1);
 263   ASSERT (errno == EBADF);
 264   errno = 0;
 265   ASSERT (fcntl (fd + 1, F_DUPFD_CLOEXEC, 0) == -1);
 266   ASSERT (errno == EBADF);
 267   errno = 0;
 268   ASSERT (fcntl (bad_fd, F_DUPFD_CLOEXEC, 0) == -1);
 269   ASSERT (errno == EBADF);
 270
 271   /* For F_DUPFD*, the destination must be valid.  */
 272   errno = 0;
 273   ASSERT (fcntl (fd, F_DUPFD, -1) == -1);
 274   ASSERT (errno == EINVAL);
 275   errno = 0;
 276   ASSERT (fcntl (fd, F_DUPFD, bad_fd) == -1);
 277   ASSERT (errno == EINVAL);
 278   errno = 0;
 279   ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, -1) == -1);
 280   ASSERT (errno == EINVAL);
 281   errno = 0;
 282   ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, bad_fd) == -1);
 283   ASSERT (errno == EINVAL
 284           || errno == EMFILE /* WSL */);
 285
 286   /* For F_DUPFD*, check for correct inheritance, as well as
 287      preservation of text vs. binary.  */
 288   set_binary_mode (fd, O_BINARY);
 289   ASSERT (is_open (fd));
 290   ASSERT (!is_open (fd + 1));
 291   ASSERT (!is_open (fd + 2));
 292   ASSERT (is_inheritable (fd));
 293   ASSERT (is_mode (fd, O_BINARY));
 294
 295   ASSERT (fcntl (fd, F_DUPFD, fd) == fd + 1);
 296   ASSERT (is_open (fd));
 297   ASSERT (is_open (fd + 1));
 298   ASSERT (!is_open (fd + 2));
 299   ASSERT (is_inheritable (fd + 1));
 300   ASSERT (is_mode (fd, O_BINARY));
 301   ASSERT (is_mode (fd + 1, O_BINARY));
 302   ASSERT (close (fd + 1) == 0);
 303
 304   ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, fd + 2) == fd + 2);
 305   ASSERT (is_open (fd));
 306   ASSERT (!is_open (fd + 1));
 307   ASSERT (is_open (fd + 2));
 308   ASSERT (is_inheritable (fd));
 309   ASSERT (!is_inheritable (fd + 2));
 310   ASSERT (is_mode (fd, O_BINARY));
 311   ASSERT (is_mode (fd + 2, O_BINARY));
 312   ASSERT (close (fd) == 0);
 313
 314   set_binary_mode (fd + 2, O_TEXT);
 315   ASSERT (fcntl (fd + 2, F_DUPFD, fd + 1) == fd + 1);
 316   ASSERT (!is_open (fd));
 317   ASSERT (is_open (fd + 1));
 318   ASSERT (is_open (fd + 2));
 319   ASSERT (is_inheritable (fd + 1));
 320   ASSERT (!is_inheritable (fd + 2));
 321   ASSERT (is_mode (fd + 1, O_TEXT));
 322   ASSERT (is_mode (fd + 2, O_TEXT));
 323   ASSERT (close (fd + 1) == 0);
 324
 325   ASSERT (fcntl (fd + 2, F_DUPFD_CLOEXEC, 0) == fd);
 326   ASSERT (is_open (fd));
 327   ASSERT (!is_open (fd + 1));
 328   ASSERT (is_open (fd + 2));
 329   ASSERT (!is_inheritable (fd));
 330   ASSERT (!is_inheritable (fd + 2));
 331   ASSERT (is_mode (fd, O_TEXT));
 332   ASSERT (is_mode (fd + 2, O_TEXT));
 333   ASSERT (close (fd + 2) == 0);
 334
 335   /* Test F_GETFD on invalid file descriptors.  */
 336   errno = 0;
 337   ASSERT (fcntl (-1, F_GETFD) == -1);
 338   ASSERT (errno == EBADF);
 339   errno = 0;
 340   ASSERT (fcntl (fd + 1, F_GETFD) == -1);
 341   ASSERT (errno == EBADF);
 342   errno = 0;
 343   ASSERT (fcntl (bad_fd, F_GETFD) == -1);
 344   ASSERT (errno == EBADF);
 345
 346   /* Test F_GETFD, the FD_CLOEXEC bit.  */
 347   {
 348     int result = fcntl (fd, F_GETFD);
 349     ASSERT (0 <= result);
 350     ASSERT ((result & FD_CLOEXEC) == FD_CLOEXEC);
 351     ASSERT (dup (fd) == fd + 1);
 352     result = fcntl (fd + 1, F_GETFD);
 353     ASSERT (0 <= result);
 354     ASSERT ((result & FD_CLOEXEC) == 0);
 355     ASSERT (close (fd + 1) == 0);
 356   }
 357
 358 #ifdef F_SETFD
 359   /* Test F_SETFD on invalid file descriptors.  */
 360   errno = 0;
 361   ASSERT (fcntl (-1, F_SETFD, 0) == -1);
 362   ASSERT (errno == EBADF);
 363   errno = 0;
 364   ASSERT (fcntl (fd + 1, F_SETFD, 0) == -1);
 365   ASSERT (errno == EBADF);
 366   errno = 0;
 367   ASSERT (fcntl (bad_fd, F_SETFD, 0) == -1);
 368   ASSERT (errno == EBADF);
 369 #endif
 370
 371 #ifdef F_GETFL
 372   /* Test F_GETFL on invalid file descriptors.  */
 373   errno = 0;
 374   ASSERT (fcntl (-1, F_GETFL) == -1);
 375   ASSERT (errno == EBADF);
 376   errno = 0;
 377   ASSERT (fcntl (fd + 1, F_GETFL) == -1);
 378   ASSERT (errno == EBADF);
 379   errno = 0;
 380   ASSERT (fcntl (bad_fd, F_GETFL) == -1);
 381   ASSERT (errno == EBADF);
 382 #endif
 383
 384 #ifdef F_SETFL
 385   /* Test F_SETFL on invalid file descriptors.  */
 386   errno = 0;
 387   ASSERT (fcntl (-1, F_SETFL, 0) == -1);
 388   ASSERT (errno == EBADF);
 389   errno = 0;
 390   ASSERT (fcntl (fd + 1, F_SETFL, 0) == -1);
 391   ASSERT (errno == EBADF);
 392   errno = 0;
 393   ASSERT (fcntl (bad_fd, F_SETFL, 0) == -1);
 394   ASSERT (errno == EBADF);
 395 #endif
 396
 397 #ifdef F_GETOWN
 398   /* Test F_GETOWN on invalid file descriptors.  */
 399   errno = 0;
 400   ASSERT (fcntl (-1, F_GETOWN) == -1);
 401   ASSERT (errno == EBADF);
 402   errno = 0;
 403   ASSERT (fcntl (fd + 1, F_GETOWN) == -1);
 404   ASSERT (errno == EBADF);
 405   errno = 0;
 406   ASSERT (fcntl (bad_fd, F_GETOWN) == -1);
 407   ASSERT (errno == EBADF);
 408 #endif
 409
 410 #ifdef F_SETOWN
 411   /* Test F_SETFL on invalid file descriptors.  */
 412   errno = 0;
 413   ASSERT (fcntl (-1, F_SETOWN, 0) == -1);
 414   ASSERT (errno == EBADF);
 415   errno = 0;
 416   ASSERT (fcntl (fd + 1, F_SETOWN, 0) == -1);
 417   ASSERT (errno == EBADF);
 418   errno = 0;
 419   ASSERT (fcntl (bad_fd, F_SETOWN, 0) == -1);
 420   ASSERT (errno == EBADF);
 421 #endif
 422
 423   /* Cleanup.  */
 424   ASSERT (close (fd) == 0);
 425   ASSERT (unlink (file) == 0);
 426
 427   /* Close file descriptors that may have been inherited from the parent
 428      process and that would cause failures below.
 429      Such file descriptors have been seen:
 430        - with GNU make, when invoked as 'make -j N' with j > 1,
 431        - in some versions of the KDE desktop environment,
 432        - on NetBSD,
 433        - in MacPorts with the "trace mode" enabled.
 434    */
 435   (void) close (10);
 436
 437   /* Test whether F_DUPFD_CLOEXEC is effective.  */
 438   ASSERT (fcntl (1, F_DUPFD_CLOEXEC, 10) >= 0);
 439   if (test_exit_status)
 440     return test_exit_status;
 441 #if defined _WIN32 && !defined __CYGWIN__
 442   return _execl ("./test-fcntl", "./test-fcntl", "child", NULL);
 443 #else
 444   return execl ("./test-fcntl", "./test-fcntl", "child", NULL);
 445 #endif
 446 }