| /* |
| * Copyright (c) International Business Machines Corp., 2001 |
| * 07/2001 Ported by Wayne Boyer |
| * Copyright (c) 2018 Cyril Hrubis <chrubis@suse.cz> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See |
| * the GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| /* |
| * Check if many children can read what is written to a pipe by the parent. |
| * |
| * ALGORITHM |
| * For a different nchilds number: |
| * 1. Open a pipe and write nchilds * (PIPE_BUF/nchilds) bytes into it |
| * 2. Fork nchilds children |
| * 3. Each child reads PIPE_BUF/nchilds characters and checks that the |
| * bytes read are correct |
| */ |
| #include <stdlib.h> |
| #include "tst_test.h" |
| |
| static int fds[2]; |
| static unsigned char buf[PIPE_BUF]; |
| static size_t read_per_child; |
| |
| void do_child(void) |
| { |
| size_t nread; |
| unsigned char rbuf[read_per_child]; |
| unsigned int i; |
| |
| SAFE_CLOSE(fds[1]); |
| |
| nread = SAFE_READ(0, fds[0], rbuf, sizeof(rbuf)); |
| |
| if (nread != read_per_child) { |
| tst_res(TFAIL, "Invalid read size child %i size %zu", |
| getpid(), nread); |
| return; |
| } |
| |
| for (i = 0; i < read_per_child; i++) { |
| if (rbuf[i] != (i % 256)) { |
| tst_res(TFAIL, |
| "Invalid byte read child %i byte %i have %i expected %i", |
| getpid(), i, rbuf[i], i % 256); |
| return; |
| } |
| } |
| |
| tst_res(TPASS, "Child %i read pipe buffer correctly", getpid()); |
| } |
| |
| static unsigned int childs[] = { |
| 1, |
| 2, |
| 3, |
| 4, |
| 10, |
| 50 |
| }; |
| |
| static void run(unsigned int tcase) |
| { |
| pid_t pid; |
| unsigned int nchilds = childs[tcase]; |
| read_per_child = PIPE_BUF/nchilds; |
| unsigned int i, j; |
| |
| tst_res(TINFO, "Reading %zu per each of %u children", |
| read_per_child, nchilds); |
| |
| for (i = 0; i < nchilds; i++) { |
| for (j = 0; j < read_per_child; j++) { |
| buf[i * read_per_child + j] = j % 256; |
| } |
| } |
| |
| SAFE_PIPE(fds); |
| |
| SAFE_WRITE(1, fds[1], buf, read_per_child * nchilds); |
| |
| for (i = 0; i < nchilds; i++) { |
| pid = SAFE_FORK(); |
| |
| if (!pid) { |
| do_child(); |
| exit(0); |
| } |
| } |
| |
| tst_reap_children(); |
| |
| SAFE_CLOSE(fds[0]); |
| SAFE_CLOSE(fds[1]); |
| } |
| |
| static struct tst_test test = { |
| .forks_child = 1, |
| .test = run, |
| .tcnt = ARRAY_SIZE(childs), |
| }; |