socket/tst-cmsg_cloexec.c

   1 /* Smoke test for MSG_CMSG_CLOEXEC.
   2    Copyright (C) 2021-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <support/xunistd.h>
  20 #include <support/check.h>
  21 #include <sys/socket.h>
  22 #include <sys/un.h>
  23 #include <string.h>
  24 #include <fcntl.h>
  25
  26 static void
  27 send_fd (int sockfd, int fd)
  28 {
  29   char data[] = "hello";
  30   struct iovec iov = { .iov_base = data, .iov_len = sizeof (data) };
  31
  32   union
  33   {
  34     struct cmsghdr header;
  35     char bytes[CMSG_SPACE (sizeof (fd))];
  36   } cmsg_storage;
  37
  38   struct msghdr msg =
  39     {
  40       .msg_iov = &iov,
  41       .msg_iovlen = 1,
  42       .msg_control = cmsg_storage.bytes,
  43       .msg_controllen = sizeof (cmsg_storage)
  44     };
  45
  46   memset (&cmsg_storage, 0, sizeof (cmsg_storage));
  47
  48   struct cmsghdr *cmsg = CMSG_FIRSTHDR (&msg);
  49   cmsg->cmsg_level = SOL_SOCKET;
  50   cmsg->cmsg_type = SCM_RIGHTS;
  51   cmsg->cmsg_len = CMSG_LEN (sizeof (fd));
  52   memcpy (CMSG_DATA (cmsg), &fd, sizeof (fd));
  53
  54   ssize_t nsent = sendmsg (sockfd, &msg, 0);
  55   if (nsent < 0)
  56     FAIL_EXIT1 ("sendmsg (%d): %m", sockfd);
  57   TEST_COMPARE (nsent, sizeof (data));
  58 }
  59
  60 static int
  61 recv_fd (int sockfd, int flags)
  62 {
  63   char buffer[100];
  64   struct iovec iov = { .iov_base = buffer, .iov_len = sizeof (buffer) };
  65
  66   union
  67   {
  68     struct cmsghdr header;
  69     char bytes[100];
  70   } cmsg_storage;
  71
  72   struct msghdr msg =
  73     {
  74       .msg_iov = &iov,
  75       .msg_iovlen = 1,
  76       .msg_control = cmsg_storage.bytes,
  77       .msg_controllen = sizeof (cmsg_storage)
  78     };
  79
  80   ssize_t nrecv = recvmsg (sockfd, &msg, flags);
  81   if (nrecv < 0)
  82     FAIL_EXIT1 ("recvmsg (%d): %m", sockfd);
  83
  84   TEST_COMPARE (msg.msg_controllen, CMSG_SPACE (sizeof (int)));
  85   struct cmsghdr *cmsg = CMSG_FIRSTHDR (&msg);
  86   TEST_COMPARE (cmsg->cmsg_level, SOL_SOCKET);
  87   TEST_COMPARE (cmsg->cmsg_type, SCM_RIGHTS);
  88   TEST_COMPARE (cmsg->cmsg_len, CMSG_LEN (sizeof (int)));
  89
  90   int fd;
  91   memcpy (&fd, CMSG_DATA (cmsg), sizeof (fd));
  92   return fd;
  93 }
  94
  95 static int
  96 do_test (void)
  97 {
  98   int sockfd[2];
  99   int newfd;
 100   int flags;
 101   int rc = socketpair (AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 0, sockfd);
 102   if (rc < 0)
 103     FAIL_EXIT1 ("socketpair: %m");
 104
 105   send_fd (sockfd[1], STDIN_FILENO);
 106   newfd = recv_fd (sockfd[0], 0);
 107   TEST_VERIFY_EXIT (newfd > 0);
 108   flags = fcntl (newfd, F_GETFD, 0);
 109   TEST_VERIFY_EXIT (flags != -1);
 110   TEST_VERIFY (!(flags & FD_CLOEXEC));
 111   xclose (newfd);
 112
 113   send_fd (sockfd[1], STDIN_FILENO);
 114   newfd = recv_fd (sockfd[0], MSG_CMSG_CLOEXEC);
 115   TEST_VERIFY_EXIT (newfd > 0);
 116   flags = fcntl (newfd, F_GETFD, 0);
 117   TEST_VERIFY_EXIT (flags != -1);
 118   TEST_VERIFY (flags & FD_CLOEXEC);
 119   xclose (newfd);
 120
 121   xclose (sockfd[0]);
 122   xclose (sockfd[1]);
 123   return 0;
 124 }
 125
 126 #include <support/test-driver.c>