1 | /* Copyright (C) 2011-2024 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either |
7 | version 2.1 of the License, or (at your option) any later version. |
8 | |
9 | The GNU C Library 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 GNU |
12 | Lesser General Public License for more details. |
13 | |
14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library; if not, see |
16 | <https://www.gnu.org/licenses/>. */ |
17 | |
18 | #include <fcntl.h> |
19 | #include <limits.h> |
20 | #include <paths.h> |
21 | #include <stdio.h> |
22 | #include <stdint.h> |
23 | #include <stdlib.h> |
24 | #include <unistd.h> |
25 | #include <sys/uio.h> |
26 | |
27 | /* GNU/Hurd does not define a IOV_MAX constraint. */ |
28 | #ifndef IOV_MAX |
29 | # define IOV_MAX 1024 |
30 | #endif |
31 | |
32 | |
33 | /* The purpose of this test is to verify that the INTERNAL_[V]SYSCALL_NCS |
34 | macros on 64-bit platforms don't cast the return type to (int) which would |
35 | erroneously sign extend the return value should the high bit of the bottom |
36 | half of the word be '1'. */ |
37 | |
38 | #if 0 |
39 | /* Used to test the non power-of-2 code path. */ |
40 | #undef IOV_MAX |
41 | #define IOV_MAX 1000 |
42 | #endif |
43 | |
44 | /* writev() should report that it has written EXPECTED number of bytes. */ |
45 | #define EXPECTED ((size_t) INT32_MAX + 1) |
46 | |
47 | static int |
48 | do_test (void) |
49 | { |
50 | struct iovec iv[IOV_MAX]; |
51 | /* POSIX doesn't guarantee that IOV_MAX is pow of 2 but we're optimistic. */ |
52 | size_t bufsz = EXPECTED / IOV_MAX; |
53 | size_t bufrem = EXPECTED % IOV_MAX; |
54 | |
55 | /* If there's a remainder then IOV_MAX probably isn't a power of 2 and we |
56 | need to make bufsz bigger so that the last iovec, iv[IOV_MAX-1], is free |
57 | for the remainder. */ |
58 | if (bufrem) |
59 | { |
60 | bufsz = bufsz + 1; |
61 | bufrem = EXPECTED - (bufsz * (IOV_MAX - 1)); |
62 | } |
63 | |
64 | /* We writev to /dev/null since we're just testing writev's return value. */ |
65 | int fd = open (_PATH_DEVNULL, O_WRONLY); |
66 | if (fd == -1) |
67 | { |
68 | printf (format: "Unable to open /dev/null for writing.\n" ); |
69 | return -1; |
70 | } |
71 | |
72 | iv[0].iov_base = malloc (size: bufsz); |
73 | if (iv[0].iov_base == NULL) |
74 | { |
75 | printf (format: "malloc (%zu) failed.\n" , bufsz); |
76 | close (fd: fd); |
77 | return -1; |
78 | } |
79 | iv[0].iov_len = bufsz; |
80 | |
81 | /* We optimistically presume that there isn't a remainder and set all iovec |
82 | instances to the same base and len as the first instance. */ |
83 | for (int i = 1; i < IOV_MAX; i++) |
84 | { |
85 | /* We don't care what the data is so reuse the allocation from iv[0]; */ |
86 | iv[i].iov_base = iv[0].iov_base; |
87 | iv[i].iov_len = iv[0].iov_len; |
88 | } |
89 | |
90 | /* If there is a remainder then we correct the last iov_len. */ |
91 | if (bufrem) |
92 | iv[IOV_MAX - 1].iov_len = bufrem; |
93 | |
94 | /* Write junk to /dev/null with the writev syscall in order to get a return |
95 | of INT32_MAX+1 bytes to verify that the INTERNAL_SYSCALL wrappers aren't |
96 | mangling the result if the signbit of a 32-bit number is set. */ |
97 | ssize_t ret = writev (fd: fd, iovec: iv, IOV_MAX); |
98 | |
99 | free (ptr: iv[0].iov_base); |
100 | close (fd: fd); |
101 | |
102 | if (ret != (ssize_t) EXPECTED) |
103 | { |
104 | #ifdef ARTIFICIAL_LIMIT |
105 | if (ret != (ssize_t) ARTIFICIAL_LIMIT) |
106 | #endif |
107 | { |
108 | printf (format: "writev() return value: %zd != EXPECTED: %zd\n" , |
109 | ret, EXPECTED); |
110 | return 1; |
111 | } |
112 | } |
113 | |
114 | return 0; |
115 | } |
116 | |
117 | #define TEST_FUNCTION do_test () |
118 | #include "../test-skeleton.c" |
119 | |