102 lines
2.0 KiB
C
102 lines
2.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (c) International Business Machines Corp., 2001
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* Ported to LTP: Wayne Boyer
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* Copyright (c) 2018 Cyril Hrubis <chrubis@suse.cz>
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*/
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/*
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* Check if many children can read what is written to a pipe by the parent.
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*
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* ALGORITHM
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* For a different nchilds number:
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* 1. Open a pipe and write nchilds * (PIPE_BUF/nchilds) bytes into it
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* 2. Fork nchilds children
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* 3. Each child reads PIPE_BUF/nchilds characters and checks that the
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* bytes read are correct
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*/
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#include <stdlib.h>
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#include "tst_test.h"
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static int fds[2];
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static unsigned char buf[PIPE_BUF];
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static size_t read_per_child;
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void do_child(void)
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{
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size_t nread;
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unsigned char rbuf[read_per_child];
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unsigned int i;
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SAFE_CLOSE(fds[1]);
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nread = SAFE_READ(0, fds[0], rbuf, sizeof(rbuf));
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if (nread != read_per_child) {
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tst_res(TFAIL, "Invalid read size child %i size %zu",
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getpid(), nread);
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return;
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}
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for (i = 0; i < read_per_child; i++) {
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if (rbuf[i] != (i % 256)) {
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tst_res(TFAIL,
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"Invalid byte read child %i byte %i have %i expected %i",
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getpid(), i, rbuf[i], i % 256);
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return;
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}
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}
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tst_res(TPASS, "Child %i read pipe buffer correctly", getpid());
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}
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static unsigned int childs[] = {
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1,
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2,
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3,
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4,
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10,
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50
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};
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static void run(unsigned int tcase)
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{
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pid_t pid;
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unsigned int nchilds = childs[tcase];
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read_per_child = PIPE_BUF/nchilds;
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unsigned int i, j;
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tst_res(TINFO, "Reading %zu per each of %u children",
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read_per_child, nchilds);
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for (i = 0; i < nchilds; i++) {
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for (j = 0; j < read_per_child; j++) {
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buf[i * read_per_child + j] = j % 256;
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}
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}
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SAFE_PIPE(fds);
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SAFE_WRITE(1, fds[1], buf, read_per_child * nchilds);
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for (i = 0; i < nchilds; i++) {
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pid = SAFE_FORK();
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if (!pid) {
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do_child();
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exit(0);
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}
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}
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tst_reap_children();
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SAFE_CLOSE(fds[0]);
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SAFE_CLOSE(fds[1]);
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}
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static struct tst_test test = {
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.forks_child = 1,
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.test = run,
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.tcnt = ARRAY_SIZE(childs),
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};
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