tests/test-select.h

   1 /* Test of select() substitute.
   2    Copyright (C) 2008-2025 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 Paolo Bonzini, 2008.  */
  18
  19 #include <stdio.h>
  20 #include <string.h>
  21 #include <sys/socket.h>
  22 #include <netinet/in.h>
  23 #include <arpa/inet.h>
  24 #include <unistd.h>
  25 #include <fcntl.h>
  26 #include <stdlib.h>
  27 #include <sys/ioctl.h>
  28 #include <errno.h>
  29
  30 #include "macros.h"
  31
  32 #if defined _WIN32 && ! defined __CYGWIN__
  33 # define WINDOWS_NATIVE
  34 #endif
  35
  36 #ifdef HAVE_SYS_WAIT_H
  37 # include <sys/wait.h>
  38 #endif
  39
  40 /* Tell GCC not to warn about the specific edge cases tested here.  */
  41 #if _GL_GNUC_PREREQ (13, 0)
  42 # pragma GCC diagnostic ignored "-Wanalyzer-fd-use-without-check"
  43 #endif
  44
  45 typedef int (*select_fn) (int, fd_set *, fd_set *, fd_set *, struct timeval *);
  46
  47
  48 /* Minimal testing infrastructure.  */
  49
  50 static int failures;
  51
  52 static void
  53 failed (const char *reason)
  54 {
  55   if (++failures > 1)
  56     printf ("  ");
  57   printf ("failed (%s)\n", reason);
  58 }
  59
  60 static int
  61 test (void (*fn) (select_fn), select_fn my_select, const char *msg)
  62 {
  63   failures = 0;
  64   printf ("%s... ", msg);
  65   fflush (stdout);
  66   fn (my_select);
  67
  68   if (!failures)
  69     printf ("passed\n");
  70
  71   return failures;
  72 }
  73
  74
  75 /* Funny socket code.  */
  76
  77 static int
  78 open_server_socket (void)
  79 {
  80   int s, x;
  81   struct sockaddr_in ia;
  82
  83   s = socket (AF_INET, SOCK_STREAM, 0);
  84
  85   x = 1;
  86   setsockopt (s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof (x));
  87
  88   memset (&ia, 0, sizeof (ia));
  89   ia.sin_family = AF_INET;
  90   inet_pton (AF_INET, "127.0.0.1", &ia.sin_addr);
  91   ia.sin_port = htons (TEST_PORT);
  92   if (bind (s, (struct sockaddr *) &ia, sizeof (ia)) < 0)
  93     {
  94       perror ("bind");
  95       exit (77);
  96     }
  97
  98   if (listen (s, 1) < 0)
  99     {
 100       perror ("listen");
 101       exit (77);
 102     }
 103
 104   return s;
 105 }
 106
 107 static int
 108 connect_to_socket (bool blocking)
 109 {
 110   int s;
 111   struct sockaddr_in ia;
 112
 113   s = socket (AF_INET, SOCK_STREAM, 0);
 114
 115   memset (&ia, 0, sizeof (ia));
 116   ia.sin_family = AF_INET;
 117   inet_pton (AF_INET, "127.0.0.1", &ia.sin_addr);
 118   ia.sin_port = htons (TEST_PORT);
 119
 120   if (!blocking)
 121     {
 122 #ifdef WINDOWS_NATIVE
 123       unsigned long iMode = 1;
 124       ioctl (s, FIONBIO, (char *) &iMode);
 125
 126 #elif defined F_GETFL
 127       int oldflags = fcntl (s, F_GETFL, NULL);
 128
 129       if (!(oldflags & O_NONBLOCK))
 130         fcntl (s, F_SETFL, oldflags | O_NONBLOCK);
 131 #endif
 132     }
 133
 134   if (connect (s, (struct sockaddr *) &ia, sizeof (ia)) < 0
 135       && (blocking || errno != EINPROGRESS))
 136     {
 137       perror ("connect");
 138       exit (77);
 139     }
 140
 141   return s;
 142 }
 143
 144
 145 /* A slightly more convenient interface to select(2).
 146    Waits until a specific event occurs on a file descriptor FD.
 147    EV is a bit mask of events to look for:
 148      SEL_IN - input can be polled without blocking,
 149      SEL_OUT - output can be provided without blocking,
 150      SEL_EXC - an exception occurred,
 151    A maximum wait time is specified by TIMEOUT.
 152    *TIMEOUT = { 0, 0 } means to return immediately,
 153    TIMEOUT = NULL means to wait indefinitely.  */
 154
 155 enum { SEL_IN = 1, SEL_OUT = 2, SEL_EXC = 4 };
 156
 157 static int
 158 do_select (int fd, int ev, struct timeval *timeout, select_fn my_select)
 159 {
 160   fd_set rfds, wfds, xfds;
 161   int r, rev;
 162
 163   FD_ZERO (&rfds);
 164   FD_ZERO (&wfds);
 165   FD_ZERO (&xfds);
 166   if (ev & SEL_IN)
 167     FD_SET (fd, &rfds);
 168   if (ev & SEL_OUT)
 169     FD_SET (fd, &wfds);
 170   if (ev & SEL_EXC)
 171     FD_SET (fd, &xfds);
 172   r = my_select (fd + 1, &rfds, &wfds, &xfds, timeout);
 173   if (r < 0)
 174     return r;
 175
 176   rev = 0;
 177   if (FD_ISSET (fd, &rfds))
 178     rev |= SEL_IN;
 179   if (FD_ISSET (fd, &wfds))
 180     rev |= SEL_OUT;
 181   if (FD_ISSET (fd, &xfds))
 182     rev |= SEL_EXC;
 183   if (rev && r == 0)
 184     failed ("select returned 0");
 185   if (rev & ~ev)
 186     failed ("select returned unrequested events");
 187
 188   return rev;
 189 }
 190
 191 static int
 192 do_select_nowait (int fd, int ev, select_fn my_select)
 193 {
 194   struct timeval tv0;
 195   tv0.tv_sec = 0;
 196   tv0.tv_usec = 0;
 197   return do_select (fd, ev, &tv0, my_select);
 198 }
 199
 200 static int
 201 do_select_wait (int fd, int ev, select_fn my_select)
 202 {
 203   return do_select (fd, ev, NULL, my_select);
 204 }
 205
 206
 207 /* Test select(2) for TTYs.  */
 208
 209 #ifdef INTERACTIVE
 210 static void
 211 test_tty (select_fn my_select)
 212 {
 213   if (do_select_nowait (0, SEL_IN, my_select) != 0)
 214     failed ("can read");
 215   if (do_select_nowait (0, SEL_OUT, my_select) == 0)
 216     failed ("cannot write");
 217
 218   if (do_select_wait (0, SEL_IN, my_select) == 0)
 219     failed ("return with infinite timeout");
 220
 221   getchar ();
 222   if (do_select_nowait (0, SEL_IN, my_select) != 0)
 223     failed ("can read after getc");
 224 }
 225 #endif
 226
 227
 228 static int
 229 do_select_bad_nfd_nowait (int nfd, select_fn my_select)
 230 {
 231   struct timeval tv0;
 232   tv0.tv_sec = 0;
 233   tv0.tv_usec = 0;
 234   errno = 0;
 235   return my_select (nfd, NULL, NULL, NULL, &tv0);
 236 }
 237
 238 static void
 239 test_bad_nfd (select_fn my_select)
 240 {
 241   if (do_select_bad_nfd_nowait (-1, my_select) != -1 || errno != EINVAL)
 242     failed ("invalid errno after negative nfds");
 243   /* Can't test FD_SETSIZE + 1 for EINVAL, since some systems allow
 244      dynamically larger set size by redefining FD_SETSIZE anywhere up
 245      to the actual maximum fd.  */
 246 #if 0
 247   if (do_select_bad_nfd_nowait (FD_SETSIZE + 1, my_select) != -1
 248       || errno != EINVAL)
 249     failed ("invalid errno after bogus nfds");
 250 #endif
 251 }
 252
 253 /* Test select(2) on invalid file descriptors.  */
 254
 255 static int
 256 do_select_bad_fd (int fd, int ev, struct timeval *timeout, select_fn my_select)
 257 {
 258   fd_set rfds, wfds, xfds;
 259
 260   FD_ZERO (&rfds);
 261   FD_ZERO (&wfds);
 262   FD_ZERO (&xfds);
 263   if (ev & SEL_IN)
 264     FD_SET (fd, &rfds);
 265   if (ev & SEL_OUT)
 266     FD_SET (fd, &wfds);
 267   if (ev & SEL_EXC)
 268     FD_SET (fd, &xfds);
 269   errno = 0;
 270   return my_select (fd + 1, &rfds, &wfds, &xfds, timeout);
 271   /* In this case, when fd is invalid, on some platforms, the bit for fd
 272      is left alone in the fd_set, whereas on other platforms it is cleared.
 273      So, don't check the bit for fd here.  */
 274 }
 275
 276 static int
 277 do_select_bad_fd_nowait (int fd, int ev, select_fn my_select)
 278 {
 279   struct timeval tv0;
 280   tv0.tv_sec = 0;
 281   tv0.tv_usec = 0;
 282   return do_select_bad_fd (fd, ev, &tv0, my_select);
 283 }
 284
 285 static void
 286 test_bad_fd (select_fn my_select)
 287 {
 288   /* This tests fails on OSF/1 and native Windows, even with fd = 16.  */
 289 #if !(defined __osf__ || defined WINDOWS_NATIVE)
 290   int fd;
 291
 292   /* On Linux, Mac OS X, *BSD, values of fd like 99 or 399 are discarded
 293      by the kernel early and therefore do *not* lead to EBADF, as required
 294      by POSIX.  */
 295 # if defined __linux__ || (defined __APPLE__ && defined __MACH__) || (defined __FreeBSD__ || defined __DragonFly__) || defined __OpenBSD__ || defined __NetBSD__
 296   fd = 14;
 297 # else
 298   fd = 99;
 299 # endif
 300   /* Even on the best POSIX compliant platforms, values of fd >= FD_SETSIZE
 301      require an nfds argument that is > FD_SETSIZE and thus may lead to EINVAL,
 302      not EBADF.  */
 303   if (fd >= FD_SETSIZE)
 304     fd = FD_SETSIZE - 1;
 305   close (fd);
 306
 307   if (do_select_bad_fd_nowait (fd, SEL_IN, my_select) == 0 || errno != EBADF)
 308     failed ("invalid fd among rfds");
 309   if (do_select_bad_fd_nowait (fd, SEL_OUT, my_select) == 0 || errno != EBADF)
 310     failed ("invalid fd among wfds");
 311   if (do_select_bad_fd_nowait (fd, SEL_EXC, my_select) == 0 || errno != EBADF)
 312     failed ("invalid fd among xfds");
 313 #endif
 314 }
 315
 316
 317 /* Test select(2) for unconnected nonblocking sockets.  */
 318
 319 static void
 320 test_connect_first (select_fn my_select)
 321 {
 322   int s = open_server_socket ();
 323   struct sockaddr_in ia;
 324   socklen_t addrlen;
 325
 326   int c1, c2;
 327
 328   if (do_select_nowait (s, SEL_IN | SEL_EXC, my_select) != 0)
 329     failed ("can read, socket not connected");
 330
 331   c1 = connect_to_socket (false);
 332
 333   if (do_select_wait (s, SEL_IN | SEL_EXC, my_select) != SEL_IN)
 334     failed ("expecting readability on passive socket");
 335   if (do_select_nowait (s, SEL_IN | SEL_EXC, my_select) != SEL_IN)
 336     failed ("expecting readability on passive socket");
 337
 338   addrlen = sizeof (ia);
 339   c2 = accept (s, (struct sockaddr *) &ia, &addrlen);
 340   ASSERT (close (s) == 0);
 341   ASSERT (close (c1) == 0);
 342   ASSERT (close (c2) == 0);
 343 }
 344
 345
 346 /* Test select(2) for unconnected blocking sockets.  */
 347
 348 static void
 349 test_accept_first (select_fn my_select)
 350 {
 351 #ifndef WINDOWS_NATIVE
 352   int s = open_server_socket ();
 353   struct sockaddr_in ia;
 354   socklen_t addrlen;
 355   char buf[3];
 356   int c, pid;
 357
 358   pid = fork ();
 359   if (pid < 0)
 360     return;
 361
 362   if (pid == 0)
 363     {
 364       addrlen = sizeof (ia);
 365       c = accept (s, (struct sockaddr *) &ia, &addrlen);
 366       ASSERT (close (s) == 0);
 367       ASSERT (write (c, "foo", 3) == 3);
 368       ASSERT (read (c, buf, 3) == 3);
 369       shutdown (c, SHUT_RD);
 370       ASSERT (close (c) == 0);
 371       exit (0);
 372     }
 373   else
 374     {
 375       ASSERT (close (s) == 0);
 376       c = connect_to_socket (true);
 377       if (do_select_nowait (c, SEL_OUT, my_select) != SEL_OUT)
 378         failed ("cannot write after blocking connect");
 379       ASSERT (write (c, "foo", 3) == 3);
 380       wait (&pid);
 381       if (do_select_wait (c, SEL_IN, my_select) != SEL_IN)
 382         failed ("cannot read data left in the socket by closed process");
 383       ASSERT (read (c, buf, 3) == 3);
 384       ASSERT (write (c, "foo", 3) == 3);
 385       (void) close (c); /* may fail with errno = ECONNRESET */
 386     }
 387 #endif
 388 }
 389
 390
 391 /* Common code for pipes and connected sockets.  */
 392
 393 static void
 394 test_pair (int rd, int wd, select_fn my_select)
 395 {
 396   char buf[3];
 397   if (do_select_wait (wd, SEL_IN | SEL_OUT | SEL_EXC, my_select) != SEL_OUT)
 398     failed ("expecting writability before writing");
 399   if (do_select_nowait (wd, SEL_IN | SEL_OUT | SEL_EXC, my_select) != SEL_OUT)
 400     failed ("expecting writability before writing");
 401
 402   ASSERT (write (wd, "foo", 3) == 3);
 403   if (do_select_wait (rd, SEL_IN, my_select) != SEL_IN)
 404     failed ("expecting readability after writing");
 405   if (do_select_nowait (rd, SEL_IN, my_select) != SEL_IN)
 406     failed ("expecting readability after writing");
 407
 408   ASSERT (read (rd, buf, 3) == 3);
 409 }
 410
 411
 412 /* Test select(2) on connected sockets.  */
 413
 414 static void
 415 test_socket_pair (select_fn my_select)
 416 {
 417   struct sockaddr_in ia;
 418
 419   socklen_t addrlen = sizeof (ia);
 420   int s = open_server_socket ();
 421   int c1 = connect_to_socket (false);
 422   int c2 = accept (s, (struct sockaddr *) &ia, &addrlen);
 423
 424   ASSERT (close (s) == 0);
 425
 426   test_pair (c1, c2, my_select);
 427   ASSERT (close (c1) == 0);
 428   ASSERT (write (c2, "foo", 3) == 3);
 429   (void) close (c2); /* may fail with errno = ECONNRESET */
 430 }
 431
 432
 433 /* Test select(2) on pipes.  */
 434
 435 static void
 436 test_pipe (select_fn my_select)
 437 {
 438   int fd[2];
 439
 440   ASSERT (pipe (fd) == 0);
 441   test_pair (fd[0], fd[1], my_select);
 442   ASSERT (close (fd[0]) == 0);
 443   ASSERT (close (fd[1]) == 0);
 444 }
 445
 446
 447 /* Do them all.  */
 448
 449 static int
 450 test_function (select_fn my_select)
 451 {
 452   int result = 0;
 453
 454 #ifdef INTERACTIVE
 455   printf ("Please press Enter\n");
 456   test (test_tty, "TTY", my_select);
 457 #endif
 458
 459   result += test (test_bad_nfd, my_select, "Invalid nfd test");
 460   result += test (test_bad_fd, my_select, "Invalid fd test");
 461   result += test (test_connect_first, my_select, "Unconnected socket test");
 462   result += test (test_socket_pair, my_select, "Connected sockets test");
 463   result += test (test_accept_first, my_select, "General socket test with fork");
 464   result += test (test_pipe, my_select, "Pipe test");
 465
 466   return result;
 467 }