1/* Common definition for tst-cancel4_* tests.
2
3 Copyright (C) 2016-2024 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#include <pthread.h>
21
22#include <support/check.h>
23#include <support/xthread.h>
24#include <support/xunistd.h>
25
26/* Pipe descriptors. */
27static int fds[2];
28
29/* Temporary file descriptor, to be closed after each round. */
30static int tempfd = -1;
31static int tempfd2 = -1;
32/* Name of temporary file to be removed after each round. */
33static char *tempfname;
34/* Temporary message queue. */
35static int tempmsg = -1;
36
37/* Often used barrier for two threads. */
38static pthread_barrier_t b2;
39
40/* The WRITE_BUFFER_SIZE value needs to be chosen such that if we set
41 the socket send buffer size to '1', a write of this size on that
42 socket will block.
43
44 The Linux kernel imposes a minimum send socket buffer size which
45 has changed over the years. As of Linux 3.10 the value is:
46
47 2 * (2048 + SKB_DATA_ALIGN(sizeof(struct sk_buff)))
48
49 which is attempting to make sure that with standard MTUs,
50 TCP can always queue up at least 2 full sized packets.
51
52 Furthermore, there is logic in the socket send paths that
53 will allow one more packet (of any size) to be queued up as
54 long as some socket buffer space remains. Blocking only
55 occurs when we try to queue up a new packet and the send
56 buffer space has already been fully consumed.
57
58 Therefore we must set this value to the largest possible value of
59 the formula above (and since it depends upon the size of "struct
60 sk_buff", it is dependent upon machine word size etc.) plus some
61 slack space. */
62
63#define WRITE_BUFFER_SIZE 16384
64
65/* Set the send buffer of socket S to 1 byte so any send operation
66 done with WRITE_BUFFER_SIZE bytes will force syscall blocking. */
67static void
68set_socket_buffer (int s)
69{
70 int val = 1;
71 socklen_t len = sizeof (val);
72
73 TEST_VERIFY_EXIT (setsockopt (s, SOL_SOCKET, SO_SNDBUF, &val,
74 sizeof (val)) == 0);
75 TEST_VERIFY_EXIT (getsockopt (s, SOL_SOCKET, SO_SNDBUF, &val, &len) == 0);
76 TEST_VERIFY_EXIT (val < WRITE_BUFFER_SIZE);
77 printf(format: "got size %d\n", val);
78}
79
80/* Cleanup handling test. */
81static int cl_called;
82
83static void
84cl (void *arg)
85{
86 ++cl_called;
87}
88
89/* Named pipe used to check for blocking open. It should be closed
90 after the cancellation handling. */
91static char fifoname[] = "/tmp/tst-cancel4-fifo-XXXXXX";
92static int fifofd;
93
94static void
95__attribute__ ((used))
96cl_fifo (void *arg)
97{
98 ++cl_called;
99
100 unlink (name: fifoname);
101 close (fd: fifofd);
102 fifofd = -1;
103}
104
105struct cancel_tests
106{
107 const char *name;
108 void *(*tf) (void *);
109 int nb;
110 int only_early;
111};
112#define ADD_TEST(name, nbar, early) { #name, tf_##name, nbar, early }
113

source code of glibc/sysdeps/pthread/tst-cancel4-common.h