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selftests: add overlayfs fd mounting selftests
Link: https://lore.kernel.org/r/[email protected] Reviewed-by: Amir Goldstein <[email protected]> Signed-off-by: Christian Brauner <[email protected]>
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‎tools/testing/selftests/filesystems/overlayfs/.gitignore

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# SPDX-License-Identifier: GPL-2.0-only
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dev_in_maps
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set_layers_via_fds

‎tools/testing/selftests/filesystems/overlayfs/Makefile

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# SPDX-License-Identifier: GPL-2.0
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TEST_GEN_PROGS := dev_in_maps
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TEST_GEN_PROGS := dev_in_maps set_layers_via_fds
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CFLAGS := -Wall -Werror
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‎tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c

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// SPDX-License-Identifier: GPL-2.0
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#define _GNU_SOURCE
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#define __SANE_USERSPACE_TYPES__ // Use ll64
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#include <fcntl.h>
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#include <sched.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/mount.h>
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#include <unistd.h>
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#include "../../kselftest_harness.h"
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#include "log.h"
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#include "wrappers.h"
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FIXTURE(set_layers_via_fds) {
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};
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FIXTURE_SETUP(set_layers_via_fds)
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{
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ASSERT_EQ(mkdir("/set_layers_via_fds", 0755), 0);
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}
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FIXTURE_TEARDOWN(set_layers_via_fds)
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{
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umount2("/set_layers_via_fds", 0);
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ASSERT_EQ(rmdir("/set_layers_via_fds"), 0);
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}
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TEST_F(set_layers_via_fds, set_layers_via_fds)
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{
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int fd_context, fd_tmpfs, fd_overlay;
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int layer_fds[] = { [0 ... 8] = -EBADF };
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bool layers_found[] = { [0 ... 8] = false };
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size_t len = 0;
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char *line = NULL;
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FILE *f_mountinfo;
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ASSERT_EQ(unshare(CLONE_NEWNS), 0);
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ASSERT_EQ(sys_mount(NULL, "/", NULL, MS_SLAVE | MS_REC, NULL), 0);
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fd_context = sys_fsopen("tmpfs", 0);
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ASSERT_GE(fd_context, 0);
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ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_CMD_CREATE, NULL, NULL, 0), 0);
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fd_tmpfs = sys_fsmount(fd_context, 0, 0);
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ASSERT_GE(fd_tmpfs, 0);
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ASSERT_EQ(close(fd_context), 0);
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ASSERT_EQ(mkdirat(fd_tmpfs, "w", 0755), 0);
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ASSERT_EQ(mkdirat(fd_tmpfs, "u", 0755), 0);
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ASSERT_EQ(mkdirat(fd_tmpfs, "l1", 0755), 0);
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ASSERT_EQ(mkdirat(fd_tmpfs, "l2", 0755), 0);
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ASSERT_EQ(mkdirat(fd_tmpfs, "l3", 0755), 0);
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ASSERT_EQ(mkdirat(fd_tmpfs, "l4", 0755), 0);
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ASSERT_EQ(mkdirat(fd_tmpfs, "d1", 0755), 0);
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ASSERT_EQ(mkdirat(fd_tmpfs, "d2", 0755), 0);
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ASSERT_EQ(mkdirat(fd_tmpfs, "d3", 0755), 0);
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layer_fds[0] = openat(fd_tmpfs, "w", O_DIRECTORY);
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ASSERT_GE(layer_fds[0], 0);
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layer_fds[1] = openat(fd_tmpfs, "u", O_DIRECTORY);
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ASSERT_GE(layer_fds[1], 0);
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layer_fds[2] = openat(fd_tmpfs, "l1", O_DIRECTORY);
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ASSERT_GE(layer_fds[2], 0);
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layer_fds[3] = openat(fd_tmpfs, "l2", O_DIRECTORY);
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ASSERT_GE(layer_fds[3], 0);
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layer_fds[4] = openat(fd_tmpfs, "l3", O_DIRECTORY);
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ASSERT_GE(layer_fds[4], 0);
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layer_fds[5] = openat(fd_tmpfs, "l4", O_DIRECTORY);
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ASSERT_GE(layer_fds[5], 0);
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layer_fds[6] = openat(fd_tmpfs, "d1", O_DIRECTORY);
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ASSERT_GE(layer_fds[6], 0);
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layer_fds[7] = openat(fd_tmpfs, "d2", O_DIRECTORY);
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ASSERT_GE(layer_fds[7], 0);
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layer_fds[8] = openat(fd_tmpfs, "d3", O_DIRECTORY);
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ASSERT_GE(layer_fds[8], 0);
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ASSERT_EQ(sys_move_mount(fd_tmpfs, "", -EBADF, "/tmp", MOVE_MOUNT_F_EMPTY_PATH), 0);
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ASSERT_EQ(close(fd_tmpfs), 0);
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fd_context = sys_fsopen("overlay", 0);
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ASSERT_GE(fd_context, 0);
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ASSERT_NE(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "lowerdir", NULL, layer_fds[2]), 0);
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ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "workdir", NULL, layer_fds[0]), 0);
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ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "upperdir", NULL, layer_fds[1]), 0);
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ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "lowerdir+", NULL, layer_fds[2]), 0);
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ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "lowerdir+", NULL, layer_fds[3]), 0);
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ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "lowerdir+", NULL, layer_fds[4]), 0);
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ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "lowerdir+", NULL, layer_fds[5]), 0);
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ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "datadir+", NULL, layer_fds[6]), 0);
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ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "datadir+", NULL, layer_fds[7]), 0);
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ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "datadir+", NULL, layer_fds[8]), 0);
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ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_STRING, "metacopy", "on", 0), 0);
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ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_CMD_CREATE, NULL, NULL, 0), 0);
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fd_overlay = sys_fsmount(fd_context, 0, 0);
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ASSERT_GE(fd_overlay, 0);
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ASSERT_EQ(sys_move_mount(fd_overlay, "", -EBADF, "/set_layers_via_fds", MOVE_MOUNT_F_EMPTY_PATH), 0);
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f_mountinfo = fopen("/proc/self/mountinfo", "r");
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ASSERT_NE(f_mountinfo, NULL);
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while (getline(&line, &len, f_mountinfo) != -1) {
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char *haystack = line;
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if (strstr(haystack, "workdir=/tmp/w"))
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layers_found[0] = true;
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if (strstr(haystack, "upperdir=/tmp/u"))
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layers_found[1] = true;
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if (strstr(haystack, "lowerdir+=/tmp/l1"))
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layers_found[2] = true;
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if (strstr(haystack, "lowerdir+=/tmp/l2"))
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layers_found[3] = true;
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if (strstr(haystack, "lowerdir+=/tmp/l3"))
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layers_found[4] = true;
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if (strstr(haystack, "lowerdir+=/tmp/l4"))
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layers_found[5] = true;
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if (strstr(haystack, "datadir+=/tmp/d1"))
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layers_found[6] = true;
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if (strstr(haystack, "datadir+=/tmp/d2"))
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layers_found[7] = true;
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if (strstr(haystack, "datadir+=/tmp/d3"))
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layers_found[8] = true;
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}
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free(line);
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for (int i = 0; i < ARRAY_SIZE(layer_fds); i++) {
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ASSERT_EQ(layers_found[i], true);
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ASSERT_EQ(close(layer_fds[i]), 0);
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}
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ASSERT_EQ(close(fd_context), 0);
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ASSERT_EQ(close(fd_overlay), 0);
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ASSERT_EQ(fclose(f_mountinfo), 0);
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}
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TEST_HARNESS_MAIN

‎tools/testing/selftests/filesystems/overlayfs/wrappers.h

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return syscall(__NR_mount, src, tgt, fst, flags, data);
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}
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#ifndef MOVE_MOUNT_F_EMPTY_PATH
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#define MOVE_MOUNT_F_EMPTY_PATH 0x00000004 /* Empty from path permitted */
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#endif
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static inline int sys_move_mount(int from_dfd, const char *from_pathname,
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int to_dfd, const char *to_pathname,
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unsigned int flags)

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