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119 lines
3.4 KiB
C
119 lines
3.4 KiB
C
/* Copyright (C) 2011-2023 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <fcntl.h>
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#include <limits.h>
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#include <paths.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/uio.h>
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/* GNU/Hurd does not define a IOV_MAX constraint. */
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#ifndef IOV_MAX
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# define IOV_MAX 1024
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#endif
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/* The purpose of this test is to verify that the INTERNAL_[V]SYSCALL_NCS
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macros on 64-bit platforms don't cast the return type to (int) which would
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erroneously sign extend the return value should the high bit of the bottom
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half of the word be '1'. */
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#if 0
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/* Used to test the non power-of-2 code path. */
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#undef IOV_MAX
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#define IOV_MAX 1000
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#endif
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/* writev() should report that it has written EXPECTED number of bytes. */
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#define EXPECTED ((size_t) INT32_MAX + 1)
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static int
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do_test (void)
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{
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struct iovec iv[IOV_MAX];
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/* POSIX doesn't guarantee that IOV_MAX is pow of 2 but we're optimistic. */
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size_t bufsz = EXPECTED / IOV_MAX;
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size_t bufrem = EXPECTED % IOV_MAX;
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/* If there's a remainder then IOV_MAX probably isn't a power of 2 and we
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need to make bufsz bigger so that the last iovec, iv[IOV_MAX-1], is free
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for the remainder. */
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if (bufrem)
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{
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bufsz = bufsz + 1;
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bufrem = EXPECTED - (bufsz * (IOV_MAX - 1));
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}
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/* We writev to /dev/null since we're just testing writev's return value. */
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int fd = open (_PATH_DEVNULL, O_WRONLY);
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if (fd == -1)
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{
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printf ("Unable to open /dev/null for writing.\n");
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return -1;
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}
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iv[0].iov_base = malloc (bufsz);
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if (iv[0].iov_base == NULL)
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{
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printf ("malloc (%zu) failed.\n", bufsz);
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close (fd);
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return -1;
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}
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iv[0].iov_len = bufsz;
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/* We optimistically presume that there isn't a remainder and set all iovec
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instances to the same base and len as the first instance. */
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for (int i = 1; i < IOV_MAX; i++)
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{
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/* We don't care what the data is so reuse the allocation from iv[0]; */
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iv[i].iov_base = iv[0].iov_base;
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iv[i].iov_len = iv[0].iov_len;
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}
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/* If there is a remainder then we correct the last iov_len. */
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if (bufrem)
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iv[IOV_MAX - 1].iov_len = bufrem;
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/* Write junk to /dev/null with the writev syscall in order to get a return
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of INT32_MAX+1 bytes to verify that the INTERNAL_SYSCALL wrappers aren't
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mangling the result if the signbit of a 32-bit number is set. */
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ssize_t ret = writev (fd, iv, IOV_MAX);
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free (iv[0].iov_base);
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close (fd);
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if (ret != (ssize_t) EXPECTED)
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{
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#ifdef ARTIFICIAL_LIMIT
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if (ret != (ssize_t) ARTIFICIAL_LIMIT)
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#endif
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{
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printf ("writev() return value: %zd != EXPECTED: %zd\n",
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ret, EXPECTED);
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return 1;
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}
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}
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return 0;
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}
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#define TEST_FUNCTION do_test ()
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#include "../test-skeleton.c"
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