[3/3] selftests: vfs: add AT_* path resolution tests

Message ID	20180929131534.24472-2-cyphar@cyphar.com (mailing list archive)
State	New
Headers	show Return-Path: <linux-kselftest-owner@kernel.org> From: Aleksa Sarai <cyphar@cyphar.com> To: Jeff Layton <jlayton@kernel.org>, "J. Bruce Fields" <bfields@fieldses.org>, Al Viro <viro@zeniv.linux.org.uk>, Arnd Bergmann <arnd@arndb.de>, Shuah Khan <shuah@kernel.org> Cc: David Howells <dhowells@redhat.com>, Andy Lutomirski <luto@kernel.org>, Christian Brauner <christian@brauner.io>, Eric Biederman <ebiederm@xmission.com>, Tycho Andersen <tycho@tycho.ws>, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org, dev@opencontainers.org, containers@lists.linux-foundation.org, Aleksa Sarai <cyphar@cyphar.com> Subject: [PATCH 3/3] selftests: vfs: add AT_* path resolution tests Date: Sat, 29 Sep 2018 23:15:34 +1000 Message-Id: <20180929131534.24472-2-cyphar@cyphar.com> In-Reply-To: <20180929131534.24472-1-cyphar@cyphar.com> References: <20180929103453.12025-1-cyphar@cyphar.com> <20180929131534.24472-1-cyphar@cyphar.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk
Series	namei: implement various scoping AT_* flags \| expand [0/3] namei: implement various scoping AT_* flags [1/3] namei: implement O_BENEATH-style AT_* flags [2/3] namei: implement AT_THIS_ROOT chroot-like path resolution [3/3] selftests: vfs: add AT_* path resolution tests

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index f1fe492c8e17..6f814e49071f 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -43,6 +43,7 @@ ifneq (1, $(quicktest)) TARGETS += timers endif TARGETS += user +TARGETS += vfs TARGETS += vm TARGETS += x86 TARGETS += zram diff --git a/tools/testing/selftests/vfs/.gitignore b/tools/testing/selftests/vfs/.gitignore new file mode 100644 index 000000000000..c57ebcba14c0 --- /dev/null +++ b/tools/testing/selftests/vfs/.gitignore @@ -0,0 +1 @@ +/vfs_helper diff --git a/tools/testing/selftests/vfs/Makefile b/tools/testing/selftests/vfs/Makefile new file mode 100644 index 000000000000..8ca3cef43dc3 --- /dev/null +++ b/tools/testing/selftests/vfs/Makefile @@ -0,0 +1,13 @@ +# SPDX-License-Identifier: GPL-2.0+ +# Author: Aleksa Sarai <cyphar@cyphar.com> +# Copyright (C) 2018 SUSE LLC. + +# Makefile for mount selftests. +CFLAGS = -Wall \ + -O2 \ + -I../../../../usr/include/ + +TEST_PROGS := $(wildcard tests/*.sh) +TEST_GEN_FILES := vfs_helper + +include ../lib.mk diff --git a/tools/testing/selftests/vfs/at_flags.h b/tools/testing/selftests/vfs/at_flags.h new file mode 100644 index 000000000000..a8ca8f689753 --- /dev/null +++ b/tools/testing/selftests/vfs/at_flags.h @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Author: Aleksa Sarai <cyphar@cyphar.com> + * Copyright (C) 2018 SUSE LLC. + */ + +#ifndef __AT_FLAGS_H__ +#define __AT_FLAGS_H__ + +/* These come from <uapi/asm-generic/linux/fcntl.h> */ +#ifndef O_BENEATH +# define O_BENEATH 00040000000 +# define O_XDEV 00100000000 +# define O_NOPROCLINKS 00200000000 +# define O_NOSYMLINKS 01000000000 +# define O_THISROOT 02000000000 +#endif +#ifndef AT_BENEATH +# define AT_BENEATH 0x8000 +# define AT_XDEV 0x10000 +# define AT_NO_PROCLINKS 0x20000 +# define AT_NO_SYMLINKS 0x40000 +# define AT_THIS_ROOT 0x80000 +#endif + +struct flag { + const char *name; + unsigned int at_flag, open_flag; +}; + +struct flag AT_FLAGS[] = { + { .name = "beneath", .at_flag = AT_BENEATH, .open_flag = O_BENEATH }, + { .name = "xdev", .at_flag = AT_XDEV, .open_flag = O_XDEV }, + { .name = "no_proclinks", .at_flag = AT_NO_PROCLINKS, .open_flag = O_NOPROCLINKS }, + { .name = "no_symlinks", .at_flag = AT_NO_SYMLINKS, .open_flag = O_NOSYMLINKS }, + { .name = "this_root", .at_flag = AT_THIS_ROOT, .open_flag = O_THISROOT }, + { 0 }, /* terminate */ +}; + +#endif /* !defined(__AT_FLAGS_H__) */ diff --git a/tools/testing/selftests/vfs/common.sh b/tools/testing/selftests/vfs/common.sh new file mode 100644 index 000000000000..82ac8ad2a5a5 --- /dev/null +++ b/tools/testing/selftests/vfs/common.sh @@ -0,0 +1,37 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0+ +# Author: Aleksa Sarai <cyphar@cyphar.com> +# Copyright (C) 2018 SUSE LLC. + +set -e -o pipefail + +tmpdir="$(mktemp -d --tmpdir vfs_test.XXXXXX)" +trap "rm -rf $tmpdir" EXIT + +root="$tmpdir/root" +mkdir -p "$root" + +function fail() { + echo "# not ok" "$@" + exit 1 +} + +ksft_skip=4 +function skip() { + echo "# skip" "$@" + exit "$ksft_skip" +} + +function run() { + local old_flags="$-" + set +eET + output="$("$@" 2>&1)" + status="$?" + set "-$old_flags" +} + +testrootdir="$(readlink -f "$(dirname "$BASH_SOURCE")")" +function vfs_helper() { + run "$testrootdir/vfs_helper" "$@" +} +vfs_ops=( "open" "stat" "lstat" ) diff --git a/tools/testing/selftests/vfs/tests/0001_at_beneath.sh b/tools/testing/selftests/vfs/tests/0001_at_beneath.sh new file mode 100755 index 000000000000..9a03b0953032 --- /dev/null +++ b/tools/testing/selftests/vfs/tests/0001_at_beneath.sh @@ -0,0 +1,72 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0+ +# Author: Aleksa Sarai <cyphar@cyphar.com> +# Copyright (C) 2018 SUSE LLC. + +sourcedir="$(readlink -f "$(dirname "$BASH_SOURCE")")" +source "$sourcedir/../common.sh" + +touch "$root/inside" +ln -s / "$root/rootlink" +ln -s .. "$root/dotdot" +ln -s "/../../../../../../$root" "$root/badlink" + +mkdir -p "$root/subdir" +ln -s ../inside "$root/subdir/dotdotinside" +ln -s ../subdir "$root/subdir/dotdotsubdir" +ln -s subdir "$root/subdirlink" +ln -s ../subdirlink/../../inside "$root/subdir/complexlink" + +for op in "${vfs_ops[@]}" +do + vfs_helper -o "$op" -F beneath -d "$root" .. + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op beneath [/root/].." + + vfs_helper -o "$op" -F beneath -d "$root" ../root + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op beneath [/root/]../root" + + vfs_helper -o "$op" -F beneath -d "$root" dotdot/root + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op beneath [/root/]dotdot(=..)/root" + + vfs_helper -o "$op" -F beneath -d "$root" "$root" + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op beneath [/root/]/root" + + vfs_helper -o "$op" -F beneath -d "$root" rootlink + if [[ "$op" == "lstat" ]] + then + [[ "$status" = 0 ]] || fail "$op beneath [/root/]rootlink(=/)" + else + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op beneath [/root/]rootlink(=/)" + fi + + vfs_helper -o "$op" -F beneath -d "$root" rootlink/ + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op beneath [/root/]rootlink(=/)/" + + vfs_helper -o "$op" -F beneath -d "$root" "rootlink/$root" + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op beneath [/root/]rootlink(=/)/root" + + vfs_helper -o "$op" -F beneath -d "$root" badlink + if [[ "$op" == "lstat" ]] + then + [[ "$status" = 0 ]] || fail "$op beneath [/root/]badlink(=/../.../root)" + else + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op beneath [/root/]badlink(=/../.../root)" + fi + + vfs_helper -o "$op" -F beneath -d "$root" subdir/../inside + [[ "$status" -eq 0 ]] || fail "$op beneath [/root/]subdir/../inside" + + vfs_helper -o "$op" -F beneath -d "$root" subdir/dotdotinside + [[ "$status" -eq 0 ]] || fail "$op beneath [/root/]subdir/dotdotinside(=../inside)" + + vfs_helper -o "$op" -F beneath -d "$root" subdir/dotdotsubdir/ + [[ "$status" -eq 0 ]] || fail "$op beneath [/root/]subdir/dotdotsubdir(=../subdir)/" + + vfs_helper -o "$op" -F beneath -d "$root" subdir/complexlink + if [[ "$op" == "lstat" ]] + then + [[ "$status" = 0 ]] || fail "$op beneath [/root/]complexlink(=../subdirlink/../../inside)" + else + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op beneath [/root/]complexlink(=../subdirlink/../../inside)" + fi +done diff --git a/tools/testing/selftests/vfs/tests/0002_at_xdev.sh b/tools/testing/selftests/vfs/tests/0002_at_xdev.sh new file mode 100755 index 000000000000..06be58a8ffe7 --- /dev/null +++ b/tools/testing/selftests/vfs/tests/0002_at_xdev.sh @@ -0,0 +1,54 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0+ +# Author: Aleksa Sarai <cyphar@cyphar.com> +# Copyright (C) 2018 SUSE LLC. + +sourcedir="$(readlink -f "$(dirname "$BASH_SOURCE")")" +source "$sourcedir/../common.sh" + +( mountpoint -q "/tmp" ) || skip "/tmp is not a mountpoint" + +touch /tmp/foo + +ln -s /tmp "$root/link_tmp" + +for op in "${vfs_ops[@]}" +do + vfs_helper -o "$op" -F xdev -d / tmp/ + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op xdev [/]tmp/" + + vfs_helper -o "$op" -F xdev -d / tmp/foo + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op xdev [/]tmp/foo" + + vfs_helper -o "$op" -F xdev -d "$root" /tmp + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op xdev [/root/]/tmp" + + vfs_helper -o "$op" -F xdev -d "$root" /tmp/ + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op xdev [/root/]/tmp/" + + vfs_helper -o "$op" -F xdev -d "$root" /tmp/foo + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op xdev [/root/]/tmp/foo" + + vfs_helper -o "$op" -F xdev -d /tmp foo + [[ "$status" = 0 ]] || fail "$op xdev [/tmp/]foo" + + vfs_helper -o "$op" -F xdev -d /tmp .. + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op xdev [/tmp/].." + + vfs_helper -o "$op" -F xdev -d /tmp ../ + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op xdev [/tmp/]../" + + vfs_helper -o "$op" -F xdev -d /tmp ../tmp + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op xdev [/tmp/]../tmp" + + vfs_helper -o "$op" -F xdev -d "$root" link_tmp + if [[ "$op" == "lstat" ]] + then + [[ "$status" = 0 ]] || fail "$op xdev [/root/]link_tmp(=/tmp)" + else + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op xdev [/root/]link_tmp(=/tmp)" + fi + + vfs_helper -o "$op" -F xdev -d "$root" link_tmp/ + [[ "$(errno "$status")" =~ "EXDEV "* ]] || fail "$op xdev [/root/]link_tmp(=/tmp)/" +done diff --git a/tools/testing/selftests/vfs/tests/0003_at_no_proclinks.sh b/tools/testing/selftests/vfs/tests/0003_at_no_proclinks.sh new file mode 100755 index 000000000000..41d9655a1e46 --- /dev/null +++ b/tools/testing/selftests/vfs/tests/0003_at_no_proclinks.sh @@ -0,0 +1,50 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0+ +# Author: Aleksa Sarai <cyphar@cyphar.com> +# Copyright (C) 2018 SUSE LLC. + +sourcedir="$(readlink -f "$(dirname "$BASH_SOURCE")")" +source "$sourcedir/../common.sh" + +[ -e "/proc/$$/cwd" ] || skip "/proc/$$/cwd doesn't exist" + +ln -s / "$root/testlink" + +for op in "${vfs_ops[@]}" +do + for flags in {no_proclinks,no_symlinks,"no_proclinks,no_symlinks"} + do + vfs_helper -o "$op" -F "$flags" "/proc/$$/stat" + [[ "$status" = 0 ]] || fail "$op $flags /proc/$$/stat" + + vfs_helper -o "$op" -F "$flags" "/proc/$$/cwd" + if [[ "$op" == "lstat" ]] + then + [[ "$status" = 0 ]] || fail "$op $flags /proc/$$/cwd" + else + [[ "$(errno "$status")" =~ "ELOOP "* ]] || fail "$op $flags /proc/$$/cwd" + fi + + vfs_helper -o "$op" -F "$flags" -d "$root" "testlink/" + if [[ "$flags" == "no_proclinks" ]] + then + [[ "$status" = 0 ]] || fail "$op $flags [/root/]testlink/" + else + [[ "$(errno "$status")" =~ "ELOOP "* ]] || fail "$op $flags [/root/]testlink/" + fi + + vfs_helper -o "$op" -F "$flags" "/proc/$$/cwd/" + [[ "$(errno "$status")" =~ "ELOOP "* ]] || fail "$op $flags /proc/$$/cwd/" + + vfs_helper -o "$op" -F "$flags" "/proc/$$/cwd/$BASH_SOURCE" + [[ "$(errno "$status")" =~ "ELOOP "* ]] || fail "$op $flags /proc/$$/cwd/$BASH_SOURCE" + + vfs_helper -o "$op" -F "$flags" -d "/proc/self" cwd + if [[ "$op" == "lstat" ]] + then + [[ "$status" = 0 ]] || fail "$op $flags [/proc/self/]cwd" + else + [[ "$(errno "$status")" =~ "ELOOP "* ]] || fail "$op $flags [/proc/self]/cwd" + fi + done +done diff --git a/tools/testing/selftests/vfs/tests/0004_at_no_symlinks.sh b/tools/testing/selftests/vfs/tests/0004_at_no_symlinks.sh new file mode 100755 index 000000000000..f7ec7e37f06a --- /dev/null +++ b/tools/testing/selftests/vfs/tests/0004_at_no_symlinks.sh @@ -0,0 +1,49 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0+ +# Author: Aleksa Sarai <cyphar@cyphar.com> +# Copyright (C) 2018 SUSE LLC. + +sourcedir="$(readlink -f "$(dirname "$BASH_SOURCE")")" +source "$sourcedir/../common.sh" + +mkdir -p "$root/dir" +touch "$root/foo" + +ln -s . "$root/link_dot" +ln -s .. "$root/link_dotdot" +ln -s foo "$root/link_foo" + +for op in "${vfs_ops[@]}" +do + vfs_helper -o "$op" -F no_symlinks -d "$root" foo + [[ "$status" = 0 ]] || fail "$op no_symlinks [/root/]foo" + + vfs_helper -o "$op" -F no_symlinks -d "$root" ../root/foo + [[ "$status" = 0 ]] || fail "$op no_symlinks [/root/]../root/foo" + + vfs_helper -o "$op" -F no_symlinks -d "$root" link_foo + if [[ "$op" == "lstat" ]] + then + [[ "$status" = 0 ]] || fail "$op no_symlinks [/root/]link_foo(=foo)" + else + [[ "$(errno "$status")" =~ "ELOOP "* ]] || fail "$op no_symlinks [/root/]link_foo(=foo)" + fi + + vfs_helper -o "$op" -F no_proclinks -d "$root" link_foo + [[ "$status" = 0 ]] || fail "$op no_proclinks [/root/]link_foo(=foo)" + + vfs_helper -o "$op" -F no_symlinks -d "$root" link_dotdot/ + [[ "$(errno "$status")" =~ "ELOOP "* ]] || fail "$op no_symlinks [/root/]link_dotdot(=..)/" + + vfs_helper -o "$op" -F no_proclinks -d "$root" link_dotdot/ + [[ "$status" = 0 ]] || fail "$op no_proclinks [/root/]link_dotdot(=..)/" + + vfs_helper -o "$op" -F no_symlinks -d "$root" link_dot/dir + [[ "$(errno "$status")" =~ "ELOOP "* ]] || fail "$op no_symlinks [/root/]link_dot(=.)/dir" + + vfs_helper -o "$op" -F no_proclinks -d "$root" link_dot/dir + [[ "$status" = 0 ]] || fail "$op no_proclinks [/root/]link_dot(=.)/dir" + + vfs_helper -o "$op" -F no_symlinks -d "$root" ../root/link_dot/link_dotdot/root/dir + [[ "$(errno "$status")" =~ "ELOOP "* ]] || fail "$op no_symlinks [/root/]../root/link_dot(=.)/link_dotdot(=..)/root/dir" +done diff --git a/tools/testing/selftests/vfs/tests/0005_at_this_root.sh b/tools/testing/selftests/vfs/tests/0005_at_this_root.sh new file mode 100755 index 000000000000..aba23c28a7b7 --- /dev/null +++ b/tools/testing/selftests/vfs/tests/0005_at_this_root.sh @@ -0,0 +1,66 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0+ +# Author: Aleksa Sarai <cyphar@cyphar.com> +# Copyright (C) 2018 SUSE LLC. + +sourcedir="$(readlink -f "$(dirname "$BASH_SOURCE")")" +source "$sourcedir/../common.sh" + +mkdir -p "$root/var" "$root/etc" "$root/usr/bin" "$root/usr/local/bin" +ln -s bash "$root/usr/bin/sh" +ln -s ../../bin/bash "$root/usr/local/bin/bash" +ln -s /bin/sh "$root/usr/local/bin/sh" +ln -s ../bin3 "$root/var/bin" +ln -s /usr/bin "$root/bin" +ln -s /usr/local/bin "$root/bin4" +ln -s ../../../../../../../../../bin "$root/bin2" +ln -s /../../../../../../../../../bin "$root/bin3" +touch "$root/etc/passwd" "$root/usr/bin/bash" + +# How should each path be mapped to a host path, in the form +# 'path:hostpath[:hostpath_trailing]'. Everything is assumed to be ${root} +# prefixed. +host_mappings=( + # Basic paths. + "..:." + "/:." + "/../../../../../../:." + "../var/../../../../../etc/passwd:etc/passwd" + "/var/../../../../../etc/passwd:etc/passwd" + "/../../../../../../var/../../../../../etc/passwd:etc/passwd" + "etc/passwd:etc/passwd" + "/etc/passwd:etc/passwd" + + # Basic symlink paths. + "/bin/bash:usr/bin/bash" + "/bin/sh:usr/bin/bash:usr/bin/sh" + "/bin2/bash:usr/bin/bash" + "/bin2/sh:usr/bin/bash:usr/bin/sh" + "/bin3/sh:usr/bin/bash:usr/bin/sh" + "/bin3/bash:usr/bin/bash" + + # More complicated symlink paths. + "/bin4/../../local/bin/bash:usr/bin/bash:usr/local/bin/bash" + "/bin4/../../local/bin/sh:usr/bin/bash:usr/local/bin/sh" + "/bin4/../../../../../../../../../../usr/local/bin/bash:usr/bin/bash:usr/local/bin/bash" + "/bin4/../../../../../../../../../../usr/local/bin/sh:usr/bin/bash:usr/local/bin/sh" + "/bin/../../bin4/../../local/bin/bash:usr/bin/bash:usr/local/bin/bash" + "/bin/../../bin4/../../local/bin/sh:usr/bin/bash:usr/local/bin/sh" +) + +for op in "${vfs_ops[@]}" +do + for mapping in "${host_mappings[@]}" + do + IFS=":" read path hostpath hostpath_trailing <<< "$mapping" + [[ "$hostpath_trailing" ]] || export hostpath_trailing="$hostpath" + [[ "$op" == "lstat" ]] && export hostpath="$hostpath_trailing" + + # Compare with and without this_root... + vfs_helper -o "$op" -d "$root" "$hostpath" + old_status="$status" old_output="$output" + vfs_helper -o "$op" -F this_root -d "$root" "$path" + [[ "$status" = "$old_status" ]] || fail "$op this_root $path=$status neq $old_status" + [[ "$output" == "$old_output" ]] || fail "$op this_root $path=$output neq $old_output" + done +done diff --git a/tools/testing/selftests/vfs/vfs_helper.c b/tools/testing/selftests/vfs/vfs_helper.c new file mode 100644 index 000000000000..d67ec74a3fca --- /dev/null +++ b/tools/testing/selftests/vfs/vfs_helper.c @@ -0,0 +1,154 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Author: Aleksa Sarai <cyphar@cyphar.com> + * Copyright (C) 2018 SUSE LLC. + */ + +#define _GNU_SOURCE + +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <limits.h> + +#include "at_flags.h" +#include "../kselftest.h" + +#define bail(...) \ + do { \ + fprintf(stderr, __VA_ARGS__); \ + fputs("\n", stderr); \ + exit(1); \ + } while (0) + +extern char *__progname; +#define usage() \ + bail("usage: %s -o {open|stat|lstat} [-d <dirfd-path>] " \ + "[-F [<flag1>,...<flagN>] <path>", __progname) + +static unsigned int parse_at_flags(char *opts) +{ + char *opt, *saveptr = NULL; + unsigned int flags = 0; + + opt = strtok_r(opts, ",", &saveptr); + do { + unsigned int found = 0; + + if (!*opt) + continue; + for (struct flag *flag = AT_FLAGS; flag->name != NULL; flag++) { + if (!strcmp(opt, flag->name)) + found |= flag->at_flag; + } + if (!found) + bail("unknown openat(2) flag: %s", opt); + flags |= found; + } while ((opt = strtok_r(NULL, ",", &saveptr)) != NULL); + + return flags; +} + +int stat_wrapper(int dirfd, const char *pathname, unsigned int flags) +{ + struct stat st = {0}; + int err; + + err = fstatat(dirfd, pathname, &st, flags); + if (err < 0) + return err; + + printf("%lu:%lu\n", st.st_dev, st.st_ino); + return 0; +} + +int lstat_wrapper(int dirfd, const char *pathname, unsigned int flags) +{ + return stat_wrapper(dirfd, pathname, flags | AT_SYMLINK_NOFOLLOW); +} + +int openat_wrapper(int dirfd, const char *pathname, unsigned int flags) +{ + int fd; + char *fdpath = NULL, fullpath[PATH_MAX] = {0}; + + fd = openat(dirfd, pathname, flags); + if (fd < 0) + return fd; + + /* Print the fully-qualified path using /proc/pid/fd/... */ + if (asprintf(&fdpath, "/proc/self/fd/%d", fd) < 0) + bail("asprintf /proc/self/fd/%d: %m", fd); + if (readlink(fdpath, fullpath, PATH_MAX) < 0) + bail("readlink %s: %m", fdpath); + puts(fullpath); + return fd; +} + +int main(int argc, char **argv) +{ + int opt, ret, dirfd; + unsigned int flags = 0; + char *opstr = NULL, *dir_path = NULL, *path = NULL; + int (*opfunc)(int dirfd, const char *pathname, unsigned int flags); + + while ((opt = getopt(argc, argv, "o:d:F:")) != -1) { + switch (opt) { + case 'o': + opstr = optarg; + break; + case 'd': + dir_path = optarg; + break; + case 'F': + flags |= parse_at_flags(optarg); + break; + default: + usage(); + } + } + + argc -= optind; + argv += optind; + + if (argc != 1) + usage(); + path = argv[0]; + + if (!opstr) + usage(); + else if (!strcmp(opstr, "stat")) + opfunc = stat_wrapper; + else if (!strcmp(opstr, "lstat")) + opfunc = lstat_wrapper; + else if (!strcmp(opstr, "open")) + opfunc = openat_wrapper; + else + usage(); + + if (opfunc == openat_wrapper) { + unsigned int open_flags = 0; + + for (struct flag *flag = AT_FLAGS; flag->name != NULL; flag++) { + if (flags & flag->at_flag) + open_flags |= flag->open_flag; + } + flags = open_flags; + } + + dirfd = AT_FDCWD; + if (dir_path) { + dirfd = open(dir_path, O_PATH|O_DIRECTORY); + if (dirfd < 0) + bail("cannot open dir_path: %m"); + } + + ret = opfunc(dirfd, path, flags); + if (ret < 0) + ret = -errno; + return (ret < 0) ? -ret : 0; +}

[3/3] selftests: vfs: add AT_* path resolution tests

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