95 lines
1.9 KiB
C
95 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#define _GNU_SOURCE
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#include <errno.h>
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#include <fcntl.h>
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#include <linux/kernel.h>
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#include <limits.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syscall.h>
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#include <unistd.h>
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#include <sys/resource.h>
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#include <linux/close_range.h>
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#include "../kselftest_harness.h"
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#include "../clone3/clone3_selftests.h"
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TEST(unshare_EMFILE)
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{
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pid_t pid;
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int status;
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struct __clone_args args = {
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.flags = CLONE_FILES,
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.exit_signal = SIGCHLD,
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};
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int fd;
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ssize_t n, n2;
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static char buf[512], buf2[512];
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struct rlimit rlimit;
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int nr_open;
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fd = open("/proc/sys/fs/nr_open", O_RDWR);
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ASSERT_GE(fd, 0);
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n = read(fd, buf, sizeof(buf));
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ASSERT_GT(n, 0);
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ASSERT_EQ(buf[n - 1], '\n');
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ASSERT_EQ(sscanf(buf, "%d", &nr_open), 1);
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ASSERT_EQ(0, getrlimit(RLIMIT_NOFILE, &rlimit));
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/* bump fs.nr_open */
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n2 = sprintf(buf2, "%d\n", nr_open + 1024);
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lseek(fd, 0, SEEK_SET);
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write(fd, buf2, n2);
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/* bump ulimit -n */
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rlimit.rlim_cur = nr_open + 1024;
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rlimit.rlim_max = nr_open + 1024;
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EXPECT_EQ(0, setrlimit(RLIMIT_NOFILE, &rlimit)) {
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lseek(fd, 0, SEEK_SET);
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write(fd, buf, n);
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exit(EXIT_FAILURE);
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}
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/* get a descriptor past the old fs.nr_open */
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EXPECT_GE(dup2(2, nr_open + 64), 0) {
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lseek(fd, 0, SEEK_SET);
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write(fd, buf, n);
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exit(EXIT_FAILURE);
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}
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/* get descriptor table shared */
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pid = sys_clone3(&args, sizeof(args));
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EXPECT_GE(pid, 0) {
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lseek(fd, 0, SEEK_SET);
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write(fd, buf, n);
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exit(EXIT_FAILURE);
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}
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if (pid == 0) {
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int err;
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/* restore fs.nr_open */
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lseek(fd, 0, SEEK_SET);
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write(fd, buf, n);
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/* ... and now unshare(CLONE_FILES) must fail with EMFILE */
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err = unshare(CLONE_FILES);
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EXPECT_EQ(err, -1)
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exit(EXIT_FAILURE);
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EXPECT_EQ(errno, EMFILE)
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exit(EXIT_FAILURE);
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exit(EXIT_SUCCESS);
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}
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EXPECT_EQ(waitpid(pid, &status, 0), pid);
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EXPECT_EQ(true, WIFEXITED(status));
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EXPECT_EQ(0, WEXITSTATUS(status));
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}
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TEST_HARNESS_MAIN
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