tests/test-fcntl.c

   1 /* Test of fcntl(2).
   2    Copyright (C) 2009-2020 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 <stdbool.h>
  31 #include <unistd.h>
  32
  33 #if defined _WIN32 && ! defined __CYGWIN__
  34 /* Get declarations of the native Windows API functions.  */
  35 # define WIN32_LEAN_AND_MEAN
  36 # include <windows.h>
  37 /* Get _get_osfhandle.  */
  38 # if GNULIB_MSVC_NOTHROW
  39 #  include "msvc-nothrow.h"
  40 # else
  41 #  include <io.h>
  42 # endif
  43 #endif
  44
  45 #include "binary-io.h"
  46 #include "macros.h"
  47
  48 #if !O_BINARY
  49 # define set_binary_mode(f,m) zero ()
  50 static int zero (void) { return 0; }
  51 #endif
  52
  53 /* Return true if FD is open.  */
  54 static bool
  55 is_open (int fd)
  56 {
  57 #if defined _WIN32 && ! defined __CYGWIN__
  58   /* On native Windows, the initial state of unassigned standard file
  59      descriptors is that they are open but point to an
  60      INVALID_HANDLE_VALUE, and there is no fcntl.  */
  61   return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
  62 #else
  63 # ifndef F_GETFL
  64 #  error Please port fcntl to your platform
  65 # endif
  66   return 0 <= fcntl (fd, F_GETFL);
  67 #endif
  68 }
  69
  70 /* Return true if FD is open and inheritable across exec/spawn.  */
  71 static bool
  72 is_inheritable (int fd)
  73 {
  74 #if defined _WIN32 && ! defined __CYGWIN__
  75   /* On native Windows, the initial state of unassigned standard file
  76      descriptors is that they are open but point to an
  77      INVALID_HANDLE_VALUE, and there is no fcntl.  */
  78   HANDLE h = (HANDLE) _get_osfhandle (fd);
  79   DWORD flags;
  80   if (h == INVALID_HANDLE_VALUE || GetHandleInformation (h, &flags) == 0)
  81     return false;
  82   return (flags & HANDLE_FLAG_INHERIT) != 0;
  83 #else
  84 # ifndef F_GETFD
  85 #  error Please port fcntl to your platform
  86 # endif
  87   int i = fcntl (fd, F_GETFD);
  88   return 0 <= i && (i & FD_CLOEXEC) == 0;
  89 #endif
  90 }
  91
  92 /* Return non-zero if FD is open in the given MODE, which is either
  93    O_TEXT or O_BINARY.  */
  94 static bool
  95 is_mode (int fd, int mode)
  96 {
  97   int value = set_binary_mode (fd, O_BINARY);
  98   set_binary_mode (fd, value);
  99   return mode == value;
 100 }
 101
 102 /* Since native fcntl can have more supported operations than our
 103    replacement is aware of, and since various operations assign
 104    different types to the vararg argument, a wrapper around fcntl must
 105    be able to pass a vararg of unknown type on through to the original
 106    fcntl.  Make sure that this works properly: func1 behaves like the
 107    original fcntl interpreting the vararg as an int or a pointer to a
 108    struct, and func2 behaves like rpl_fcntl that doesn't know what
 109    type to forward.  */
 110 struct dummy_struct
 111 {
 112   long filler;
 113   int value;
 114 };
 115 static int
 116 func1 (int a, ...)
 117 {
 118   va_list arg;
 119   int i;
 120   va_start (arg, a);
 121   if (a < 4)
 122     i = va_arg (arg, int);
 123   else
 124     {
 125       struct dummy_struct *s = va_arg (arg, struct dummy_struct *);
 126       i = s->value;
 127     }
 128   va_end (arg);
 129   return i;
 130 }
 131 static int
 132 func2 (int a, ...)
 133 {
 134   va_list arg;
 135   void *p;
 136   va_start (arg, a);
 137   p = va_arg (arg, void *);
 138   va_end (arg);
 139   return func1 (a, p);
 140 }
 141
 142 /* Ensure that all supported fcntl actions are distinct, and
 143    usable in preprocessor expressions.  */
 144 static void
 145 check_flags (void)
 146 {
 147   switch (0)
 148     {
 149     case F_DUPFD:
 150 #if F_DUPFD
 151 #endif
 152
 153     case F_DUPFD_CLOEXEC:
 154 #if F_DUPFD_CLOEXEC
 155 #endif
 156
 157     case F_GETFD:
 158 #if F_GETFD
 159 #endif
 160
 161 #ifdef F_SETFD
 162     case F_SETFD:
 163 # if F_SETFD
 164 # endif
 165 #endif
 166
 167 #ifdef F_GETFL
 168     case F_GETFL:
 169 # if F_GETFL
 170 # endif
 171 #endif
 172
 173 #ifdef F_SETFL
 174     case F_SETFL:
 175 # if F_SETFL
 176 # endif
 177 #endif
 178
 179 #ifdef F_GETOWN
 180     case F_GETOWN:
 181 # if F_GETOWN
 182 # endif
 183 #endif
 184
 185 #ifdef F_SETOWN
 186     case F_SETOWN:
 187 # if F_SETOWN
 188 # endif
 189 #endif
 190
 191 #ifdef F_GETLK
 192     case F_GETLK:
 193 # if F_GETLK
 194 # endif
 195 #endif
 196
 197 #ifdef F_SETLK
 198     case F_SETLK:
 199 # if F_SETLK
 200 # endif
 201 #endif
 202
 203 #ifdef F_SETLKW
 204     case F_SETLKW:
 205 # if F_SETLKW
 206 # endif
 207 #endif
 208
 209     default:
 210       ;
 211     }
 212 }
 213
 214 int
 215 main (void)
 216 {
 217   const char *file = "test-fcntl.tmp";
 218   int fd;
 219   int bad_fd = getdtablesize ();
 220
 221   /* Sanity check that rpl_fcntl is likely to work.  */
 222   ASSERT (func2 (1, 2) == 2);
 223   ASSERT (func2 (2, -2) == -2);
 224   ASSERT (func2 (3, 0x80000000) == 0x80000000);
 225   {
 226     struct dummy_struct s = { 0L, 4 };
 227     ASSERT (func2 (4, &s) == 4);
 228   }
 229   check_flags ();
 230
 231   /* Assume std descriptors were provided by invoker, and ignore fds
 232      that might have been inherited.  */
 233   fd = creat (file, 0600);
 234   ASSERT (STDERR_FILENO < fd);
 235   close (fd + 1);
 236   close (fd + 2);
 237
 238   /* For F_DUPFD*, the source must be valid.  */
 239   errno = 0;
 240   ASSERT (fcntl (-1, F_DUPFD, 0) == -1);
 241   ASSERT (errno == EBADF);
 242   errno = 0;
 243   ASSERT (fcntl (fd + 1, F_DUPFD, 0) == -1);
 244   ASSERT (errno == EBADF);
 245   errno = 0;
 246   ASSERT (fcntl (bad_fd, F_DUPFD, 0) == -1);
 247   ASSERT (errno == EBADF);
 248   errno = 0;
 249   ASSERT (fcntl (-1, F_DUPFD_CLOEXEC, 0) == -1);
 250   ASSERT (errno == EBADF);
 251   errno = 0;
 252   ASSERT (fcntl (fd + 1, F_DUPFD_CLOEXEC, 0) == -1);
 253   ASSERT (errno == EBADF);
 254   errno = 0;
 255   ASSERT (fcntl (bad_fd, F_DUPFD_CLOEXEC, 0) == -1);
 256   ASSERT (errno == EBADF);
 257
 258   /* For F_DUPFD*, the destination must be valid.  */
 259   errno = 0;
 260   ASSERT (fcntl (fd, F_DUPFD, -1) == -1);
 261   ASSERT (errno == EINVAL);
 262   errno = 0;
 263   ASSERT (fcntl (fd, F_DUPFD, bad_fd) == -1);
 264   ASSERT (errno == EINVAL);
 265   errno = 0;
 266   ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, -1) == -1);
 267   ASSERT (errno == EINVAL);
 268   errno = 0;
 269   ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, bad_fd) == -1);
 270   ASSERT (errno == EINVAL
 271           || errno == EMFILE /* WSL */);
 272
 273   /* For F_DUPFD*, check for correct inheritance, as well as
 274      preservation of text vs. binary.  */
 275   set_binary_mode (fd, O_BINARY);
 276   ASSERT (is_open (fd));
 277   ASSERT (!is_open (fd + 1));
 278   ASSERT (!is_open (fd + 2));
 279   ASSERT (is_inheritable (fd));
 280   ASSERT (is_mode (fd, O_BINARY));
 281
 282   ASSERT (fcntl (fd, F_DUPFD, fd) == fd + 1);
 283   ASSERT (is_open (fd));
 284   ASSERT (is_open (fd + 1));
 285   ASSERT (!is_open (fd + 2));
 286   ASSERT (is_inheritable (fd + 1));
 287   ASSERT (is_mode (fd, O_BINARY));
 288   ASSERT (is_mode (fd + 1, O_BINARY));
 289   ASSERT (close (fd + 1) == 0);
 290
 291   ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, fd + 2) == fd + 2);
 292   ASSERT (is_open (fd));
 293   ASSERT (!is_open (fd + 1));
 294   ASSERT (is_open (fd + 2));
 295   ASSERT (is_inheritable (fd));
 296   ASSERT (!is_inheritable (fd + 2));
 297   ASSERT (is_mode (fd, O_BINARY));
 298   ASSERT (is_mode (fd + 2, O_BINARY));
 299   ASSERT (close (fd) == 0);
 300
 301   set_binary_mode (fd + 2, O_TEXT);
 302   ASSERT (fcntl (fd + 2, F_DUPFD, fd + 1) == fd + 1);
 303   ASSERT (!is_open (fd));
 304   ASSERT (is_open (fd + 1));
 305   ASSERT (is_open (fd + 2));
 306   ASSERT (is_inheritable (fd + 1));
 307   ASSERT (!is_inheritable (fd + 2));
 308   ASSERT (is_mode (fd + 1, O_TEXT));
 309   ASSERT (is_mode (fd + 2, O_TEXT));
 310   ASSERT (close (fd + 1) == 0);
 311
 312   ASSERT (fcntl (fd + 2, F_DUPFD_CLOEXEC, 0) == fd);
 313   ASSERT (is_open (fd));
 314   ASSERT (!is_open (fd + 1));
 315   ASSERT (is_open (fd + 2));
 316   ASSERT (!is_inheritable (fd));
 317   ASSERT (!is_inheritable (fd + 2));
 318   ASSERT (is_mode (fd, O_TEXT));
 319   ASSERT (is_mode (fd + 2, O_TEXT));
 320   ASSERT (close (fd + 2) == 0);
 321
 322   /* Test F_GETFD on invalid file descriptors.  */
 323   errno = 0;
 324   ASSERT (fcntl (-1, F_GETFD) == -1);
 325   ASSERT (errno == EBADF);
 326   errno = 0;
 327   ASSERT (fcntl (fd + 1, F_GETFD) == -1);
 328   ASSERT (errno == EBADF);
 329   errno = 0;
 330   ASSERT (fcntl (bad_fd, F_GETFD) == -1);
 331   ASSERT (errno == EBADF);
 332
 333   /* Test F_GETFD, the FD_CLOEXEC bit.  */
 334   {
 335     int result = fcntl (fd, F_GETFD);
 336     ASSERT (0 <= result);
 337     ASSERT ((result & FD_CLOEXEC) == FD_CLOEXEC);
 338     ASSERT (dup (fd) == fd + 1);
 339     result = fcntl (fd + 1, F_GETFD);
 340     ASSERT (0 <= result);
 341     ASSERT ((result & FD_CLOEXEC) == 0);
 342     ASSERT (close (fd + 1) == 0);
 343   }
 344
 345 #ifdef F_SETFD
 346   /* Test F_SETFD on invalid file descriptors.  */
 347   errno = 0;
 348   ASSERT (fcntl (-1, F_SETFD, 0) == -1);
 349   ASSERT (errno == EBADF);
 350   errno = 0;
 351   ASSERT (fcntl (fd + 1, F_SETFD, 0) == -1);
 352   ASSERT (errno == EBADF);
 353   errno = 0;
 354   ASSERT (fcntl (bad_fd, F_SETFD, 0) == -1);
 355   ASSERT (errno == EBADF);
 356 #endif
 357
 358 #ifdef F_GETFL
 359   /* Test F_GETFL on invalid file descriptors.  */
 360   errno = 0;
 361   ASSERT (fcntl (-1, F_GETFL) == -1);
 362   ASSERT (errno == EBADF);
 363   errno = 0;
 364   ASSERT (fcntl (fd + 1, F_GETFL) == -1);
 365   ASSERT (errno == EBADF);
 366   errno = 0;
 367   ASSERT (fcntl (bad_fd, F_GETFL) == -1);
 368   ASSERT (errno == EBADF);
 369 #endif
 370
 371 #ifdef F_SETFL
 372   /* Test F_SETFL on invalid file descriptors.  */
 373   errno = 0;
 374   ASSERT (fcntl (-1, F_SETFL, 0) == -1);
 375   ASSERT (errno == EBADF);
 376   errno = 0;
 377   ASSERT (fcntl (fd + 1, F_SETFL, 0) == -1);
 378   ASSERT (errno == EBADF);
 379   errno = 0;
 380   ASSERT (fcntl (bad_fd, F_SETFL, 0) == -1);
 381   ASSERT (errno == EBADF);
 382 #endif
 383
 384 #ifdef F_GETOWN
 385   /* Test F_GETOWN on invalid file descriptors.  */
 386   errno = 0;
 387   ASSERT (fcntl (-1, F_GETOWN) == -1);
 388   ASSERT (errno == EBADF);
 389   errno = 0;
 390   ASSERT (fcntl (fd + 1, F_GETOWN) == -1);
 391   ASSERT (errno == EBADF);
 392   errno = 0;
 393   ASSERT (fcntl (bad_fd, F_GETOWN) == -1);
 394   ASSERT (errno == EBADF);
 395 #endif
 396
 397 #ifdef F_SETOWN
 398   /* Test F_SETFL on invalid file descriptors.  */
 399   errno = 0;
 400   ASSERT (fcntl (-1, F_SETOWN, 0) == -1);
 401   ASSERT (errno == EBADF);
 402   errno = 0;
 403   ASSERT (fcntl (fd + 1, F_SETOWN, 0) == -1);
 404   ASSERT (errno == EBADF);
 405   errno = 0;
 406   ASSERT (fcntl (bad_fd, F_SETOWN, 0) == -1);
 407   ASSERT (errno == EBADF);
 408 #endif
 409
 410   /* Cleanup.  */
 411   ASSERT (close (fd) == 0);
 412   ASSERT (unlink (file) == 0);
 413
 414   return 0;
 415 }