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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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9a0584f056
It appears that newer glibcs check that openat(O_CREAT) was provided a fourth argument (rather than passing garbage), resulting in the following build error: > In file included from /usr/include/fcntl.h:301, > from helpers.c:9: > In function 'openat', > inlined from 'touchat' at helpers.c:49:11: > /usr/include/x86_64-linux-gnu/bits/fcntl2.h:126:4: error: call to > '__openat_missing_mode' declared with attribute error: openat with O_CREAT > or O_TMPFILE in third argument needs 4 arguments > 126 | __openat_missing_mode (); > | ^~~~~~~~~~~~~~~~~~~~~~~~ Reported-by: Shuah Khan <shuah@kernel.org> Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> Tested-by: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
109 lines
2.1 KiB
C
109 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Author: Aleksa Sarai <cyphar@cyphar.com>
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* Copyright (C) 2018-2019 SUSE LLC.
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*/
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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 <stdbool.h>
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#include <string.h>
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#include <syscall.h>
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#include <limits.h>
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#include "helpers.h"
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bool needs_openat2(const struct open_how *how)
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{
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return how->resolve != 0;
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}
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int raw_openat2(int dfd, const char *path, void *how, size_t size)
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{
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int ret = syscall(__NR_openat2, dfd, path, how, size);
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return ret >= 0 ? ret : -errno;
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}
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int sys_openat2(int dfd, const char *path, struct open_how *how)
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{
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return raw_openat2(dfd, path, how, sizeof(*how));
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}
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int sys_openat(int dfd, const char *path, struct open_how *how)
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{
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int ret = openat(dfd, path, how->flags, how->mode);
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return ret >= 0 ? ret : -errno;
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}
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int sys_renameat2(int olddirfd, const char *oldpath,
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int newdirfd, const char *newpath, unsigned int flags)
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{
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int ret = syscall(__NR_renameat2, olddirfd, oldpath,
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newdirfd, newpath, flags);
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return ret >= 0 ? ret : -errno;
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}
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int touchat(int dfd, const char *path)
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{
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int fd = openat(dfd, path, O_CREAT, 0700);
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if (fd >= 0)
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close(fd);
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return fd;
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}
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char *fdreadlink(int fd)
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{
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char *target, *tmp;
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E_asprintf(&tmp, "/proc/self/fd/%d", fd);
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target = malloc(PATH_MAX);
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if (!target)
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ksft_exit_fail_msg("fdreadlink: malloc failed\n");
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memset(target, 0, PATH_MAX);
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E_readlink(tmp, target, PATH_MAX);
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free(tmp);
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return target;
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}
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bool fdequal(int fd, int dfd, const char *path)
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{
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char *fdpath, *dfdpath, *other;
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bool cmp;
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fdpath = fdreadlink(fd);
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dfdpath = fdreadlink(dfd);
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if (!path)
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E_asprintf(&other, "%s", dfdpath);
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else if (*path == '/')
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E_asprintf(&other, "%s", path);
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else
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E_asprintf(&other, "%s/%s", dfdpath, path);
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cmp = !strcmp(fdpath, other);
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free(fdpath);
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free(dfdpath);
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free(other);
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return cmp;
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}
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bool openat2_supported = false;
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void __attribute__((constructor)) init(void)
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{
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struct open_how how = {};
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int fd;
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BUILD_BUG_ON(sizeof(struct open_how) != OPEN_HOW_SIZE_VER0);
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/* Check openat2(2) support. */
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fd = sys_openat2(AT_FDCWD, ".", &how);
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openat2_supported = (fd >= 0);
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if (fd >= 0)
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close(fd);
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}
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