tree-wide: include unistd.h where necessary

We use symbols provided by unistd.h without including it. E.g.
open(), close(), read(), write(), access(), symlink(), unlink(), rmdir(),
fsync(), syncfs(), lseek(), ftruncate(), fchown(), dup2(), pipe2(),
getuid(), getgid(), gettid(), getppid(), pipe2(), execv(), _exit(),
environ, STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO, F_OK, and their
friends and variants, so on.

Currently, unistd.h is indirectly included mainly in the following two paths:
- through missing_syscall.h, which is planned to covert to .c file.
- through signal.h -> bits/sigstksz.h, which is new since glibc-2.34.
  Note, signal.h is included by sd-eevent.h. So, many source files
  indirectly include unistd.h if newer glibc is used.

Currently, our baseline on glibc is 2.31. We need to support glibc older
than 2.34, but unfortunately, we do not have any CI environments with
such old glibc. CIFuzz uses glibc-2.31, but it builds only fuzzers, and
many files are even not compiled.

src/analyze/analyze-condition.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "analyze.h"
 #include "analyze-condition.h"

src/analyze/analyze-verify-util.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 

src/basic/hashmap.c

@@ -2,6 +2,7 @@
 
 #include <fnmatch.h>
 #include <pthread.h>
+#include <unistd.h>
 #if HAVE_VALGRIND_VALGRIND_H
 #  include <valgrind/valgrind.h>
 #endif

src/basic/lock-util.c

@@ -6,6 +6,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/file.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "errno-util.h"

src/basic/namespace-util.c

@@ -3,6 +3,7 @@
 #include <fcntl.h>
 #include <sys/ioctl.h>
 #include <sys/mount.h>
+#include <unistd.h>
 
 #include "errno-util.h"
 #include "fd-util.h"

src/basic/pidref.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "alloc-util.h"
 #include "errno-util.h"
 #include "fd-util.h"

src/basic/random-util.c

@@ -7,6 +7,7 @@
 #include <sys/auxv.h>
 #include <sys/ioctl.h>
 #include <threads.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "fd-util.h"

src/basic/signal-util.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <threads.h>
+#include <unistd.h>
 
 #include "errno-util.h"
 #include "missing_syscall.h"

src/core/cgroup.c

@@ -2,6 +2,7 @@
 
 #include <fcntl.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 #include "sd-messages.h"

src/core/crash-handler.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <sys/reboot.h>
+#include <unistd.h>
 
 #include "sd-messages.h"
 

src/core/dbus-execute.c

@@ -2,6 +2,7 @@
 
 #include <syslog.h>
 #include <sys/mount.h>
+#include <unistd.h>
 
 #include "af-list.h"
 #include "alloc-util.h"

src/core/dbus-unit.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "sd-bus.h"
 
 #include "alloc-util.h"

src/core/dynamic-user.c

@@ -3,6 +3,7 @@
 #include <grp.h>
 #include <sys/file.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "clean-ipc.h"
 #include "dynamic-user.h"

src/core/emergency-action.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <sys/reboot.h>
+#include <unistd.h>
 
 #include "ansi-color.h"
 #include "emergency-action.h"

src/core/exec-credential.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <sys/mount.h>
+#include <unistd.h>
 
 #include "acl-util.h"
 #include "cgroup.h"

src/core/exec-invoke.c

@@ -10,6 +10,7 @@
 #include <sys/ioctl.h>
 #include <sys/mount.h>
 #include <sys/prctl.h>
+#include <unistd.h>
 
 #if HAVE_PAM
 #include <security/pam_appl.h>

src/core/execute-serialize.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "af-list.h"
 #include "capability-util.h"
 #include "cgroup.h"

src/core/import-creds.c

@@ -2,6 +2,7 @@
 
 #include <stdlib.h>
 #include <sys/mount.h>
+#include <unistd.h>
 
 #include "confidential-virt.h"
 #include "copy.h"

src/core/load-fragment.c

@@ -5,6 +5,7 @@
 
 #include <fcntl.h>
 #include <sched.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 #include "sd-messages.h"

src/core/selinux-access.c

@@ -6,6 +6,7 @@
 
 #include <selinux/avc.h>
 #include <selinux/selinux.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 

src/home/homectl.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <getopt.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 

src/home/homed-home.c

@@ -2,6 +2,7 @@
 
 #include <sys/mman.h>
 #include <sys/vfs.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 

src/home/homed-manager-bus.c

@@ -2,6 +2,7 @@
 
 #include <grp.h>
 #include <pwd.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 #include "sd-event.h"

src/home/homed-manager.c

@@ -9,6 +9,7 @@
 #include <sys/inotify.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 #include "sd-event.h"

src/home/homework-cifs.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <sys/mount.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "env-util.h"

src/home/homework-fscrypt.c

@@ -7,6 +7,7 @@
 #include <sys/mount.h>
 #include <sys/stat.h>
 #include <sys/xattr.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "errno-util.h"

src/home/homework-luks.c

@@ -5,6 +5,7 @@
 #include <sys/file.h>
 #include <sys/ioctl.h>
 #include <sys/xattr.h>
+#include <unistd.h>
 #if HAVE_VALGRIND_MEMCHECK_H
 #include <valgrind/memcheck.h>
 #endif

src/home/homework.c

@@ -2,6 +2,7 @@
 
 #include <stdlib.h>
 #include <sys/mount.h>
+#include <unistd.h>
 
 #include "sd-daemon.h"
 

src/import/import-fs.c

@@ -2,6 +2,7 @@
 
 #include <getopt.h>
 #include <locale.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "ansi-color.h"

src/import/import.c

@@ -2,6 +2,7 @@
 
 #include <getopt.h>
 #include <locale.h>
+#include <unistd.h>
 
 #include "sd-event.h"
 

src/import/importctl.c

@@ -2,6 +2,7 @@
 
 #include <getopt.h>
 #include <locale.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 #include "sd-event.h"

src/import/importd.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 #include "sd-daemon.h"

src/journal-remote/fuzz-journal-remote.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "sd-journal.h"
 

src/journal/fuzz-journald-native-fd.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "fd-util.h"
 #include "fuzz.h"
 #include "fuzz-journald.h"

src/journal/journald-context.c

@@ -5,6 +5,7 @@
 #endif
 
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "audit-util.h"

src/journal/journald-manager.c

@@ -6,6 +6,7 @@
 #include <sys/mman.h>
 #include <sys/signalfd.h>
 #include <sys/statvfs.h>
+#include <unistd.h>
 
 #include "sd-daemon.h"
 #include "sd-journal.h"

src/libsystemd-network/sd-dhcp-server-lease.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "sd-event.h"
 

src/libsystemd/sd-bus/test-bus-watch-bind.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <pthread.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 #include "sd-event.h"

src/libsystemd/sd-event/sd-event.c

@@ -5,6 +5,7 @@
 #include <sys/timerfd.h>
 #include <sys/wait.h>
 #include <threads.h>
+#include <unistd.h>
 
 #include "sd-daemon.h"
 #include "sd-event.h"

src/libudev/libudev-device.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "libudev.h"
 #include "sd-device.h"
 

src/login/logind-brightness.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "sd-bus.h"
 #include "sd-device.h"
 #include "sd-event.h"

src/machine/image-dbus.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "sd-bus.h"
 
 #include "alloc-util.h"

src/machine/image-varlink.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "sd-json.h"
 #include "sd-varlink.h"
 

src/machine/image.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "sd-bus.h"
 
 #include "discover-image.h"

src/machine/machined-core.c

@@ -1,6 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "sd-event.h"
+
 #include "cgroup-util.h"
 #include "copy.h"
 #include "discover-image.h"

src/mountfsd/mountfsd-manager.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "sd-daemon.h"
 

src/mountfsd/mountwork.c

@@ -4,6 +4,7 @@
 #include <poll.h>
 #include <stdlib.h>
 #include <sys/mount.h>
+#include <unistd.h>
 
 #include "sd-daemon.h"
 #include "sd-event.h"

src/network/networkd.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "sd-event.h"
 

src/nspawn/nspawn-mount.c

@@ -2,6 +2,7 @@
 
 #include <linux/magic.h>
 #include <sys/mount.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "chase.h"

src/nspawn/nspawn-network.c

@@ -6,6 +6,7 @@
 #include <net/if.h>
 #include <sys/file.h>
 #include <sys/mount.h>
+#include <unistd.h>
 
 #include "sd-device.h"
 #include "sd-id128.h"

src/nsresourced/nsresourced-manager.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "sd-daemon.h"
 

src/nsresourced/nsresourcework.c

@@ -9,6 +9,7 @@
 #include <sys/eventfd.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
+#include <unistd.h>
 #include <utmpx.h>
 
 #include "sd-daemon.h"

src/nsresourced/test-userns-restrict.c

@@ -3,6 +3,7 @@
 #include <sys/eventfd.h>
 #include <sys/mount.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "errno-util.h"
 #include "fd-util.h"

src/portable/portable.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <linux/loop.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 #include "sd-messages.h"

src/repart/repart.c

@@ -5,6 +5,7 @@
 #include <sys/file.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "sd-id128.h"
 #include "sd-json.h"

src/run/run.c

@@ -5,6 +5,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/resource.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 #include "sd-daemon.h"

src/shared/bus-polkit.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "sd-bus.h"
 #include "sd-event.h"
 

src/shared/dissect-image.c

@@ -4,6 +4,7 @@
 #include <linux/loop.h>
 #include <sys/file.h>
 #include <sys/mount.h>
+#include <unistd.h>
 
 #if HAVE_OPENSSL
 #include <openssl/err.h>

src/shared/edit-util.c

@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "copy.h"

src/shared/journal-util.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "sd-bus.h"
 #include "sd-journal.h"
 

src/shared/portable-util.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "alloc-util.h"
 #include "fs-util.h"
 #include "nulstr-util.h"

src/shared/serialize.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <fcntl.h>
+#include <unistd.h>
 
 #include "sd-id128.h"
 

src/shared/tests.c

@@ -5,6 +5,7 @@
 #include <sys/mman.h>
 #include <sys/prctl.h>
 #include <sys/wait.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 #include "sd-daemon.h"

src/sulogin-shell/sulogin-shell.c

@@ -3,6 +3,8 @@
   Copyright © 2017 Felipe Sateler
 ***/
 
+#include <unistd.h>
+
 #include "sd-bus.h"
 
 #include "alloc-util.h"

src/systemctl/systemctl-sysv-compat.c

@@ -2,6 +2,7 @@
 
 #include <fcntl.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "env-util.h"
 #include "fd-util.h"

src/sysupdate/sysupdate-transfer.c

@@ -2,6 +2,7 @@
 
 #include <stdlib.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "sd-id128.h"
 

src/sysupdate/sysupdated.c

@@ -2,6 +2,7 @@
 
 #include <stdlib.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 #include "sd-json.h"

src/test/test-cgroup-util.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "alloc-util.h"
 #include "cgroup-util.h"
 #include "errno-util.h"

src/test/test-conf-files.c

@@ -4,6 +4,7 @@
 ***/
 
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "conf-files.h"

src/test/test-conf-parser.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "conf-parser.h"
 #include "fd-util.h"
 #include "fileio.h"

src/test/test-dirent-util.c

@@ -4,6 +4,7 @@
 #include <stdlib.h>
 #include <sys/stat.h>
 #include <sys/sysmacros.h>
+#include <unistd.h>
 
 #include "dirent-util.h"
 #include "fs-util.h"

src/test/test-env-util.c

@@ -1,6 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <stdlib.h>
+#include <unistd.h>
+
 #include "env-util.h"
 #include "parse-util.h"
 #include "process-util.h"

src/test/test-execute.c

@@ -6,6 +6,7 @@
 #include <stdlib.h>
 #include <sys/mount.h>
 #include <sys/prctl.h>
+#include <unistd.h>
 
 #include "sd-event.h"
 

src/test/test-hashmap-plain.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "alloc-util.h"
 #include "hashmap.h"
 #include "log.h"

src/test/test-json.c

@@ -3,6 +3,7 @@
 #include <float.h>
 #include <sys/socket.h>
 #include <sys/sysmacros.h>
+#include <unistd.h>
 
 #include "sd-json.h"
 

src/test/test-loop-block.c

@@ -6,6 +6,7 @@
 #include <pthread.h>
 #include <sys/file.h>
 #include <sys/ioctl.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "capability-util.h"

src/test/test-macro.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "sd-id128.h"
 

src/test/test-memfd-util.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "errno-util.h"
 #include "fd-util.h"
 #include "memfd-util.h"

src/test/test-mount-util.c

@@ -3,6 +3,7 @@
 #include <sys/mount.h>
 #include <sys/stat.h>
 #include <sys/statvfs.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "capability-util.h"

src/test/test-namespace.c

@@ -6,6 +6,7 @@
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sysexits.h>
+#include <unistd.h>
 
 #include "sd-id128.h"
 

src/test/test-os-util.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "fileio.h"
 #include "log.h"

src/test/test-path.c

@@ -2,6 +2,7 @@
 
 #include <stdlib.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "all-units.h"
 #include "alloc-util.h"

src/test/test-proc-cmdline.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "errno-util.h"

src/test/test-psi-util.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "fd-util.h"
 #include "fileio.h"
 #include "parse-util.h"

src/test/test-rlimit-util.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <sys/resource.h>
+#include <unistd.h>
 #if HAVE_VALGRIND_VALGRIND_H
 #include <valgrind/valgrind.h>
 #endif

src/test/test-set.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "random-util.h"
 #include "set.h"
 #include "strv.h"

src/test/test-string-util.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "alloc-util.h"
 #include "extract-word.h"
 #include "locale-util.h"

src/test/test-tmpfile-util.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "argv-util.h"

src/test/test-uid-range.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "errno-util.h"
 #include "fd-util.h"
 #include "fileio.h"

src/test/test-unit-file.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "argv-util.h"
 #include "fileio.h"
 #include "initrd-util.h"

src/test/test-unit-name.c

@@ -2,6 +2,7 @@
 
 #include <fnmatch.h>
 #include <stdio.h>
+#include <unistd.h>
 
 #include "sd-daemon.h"
 #include "sd-id128.h"

src/test/test-user-util.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "alloc-util.h"
 #include "format-util.h"
 #include "libcrypt-util.h"

src/test/test-varlink.c

@@ -4,6 +4,7 @@
 #include <poll.h>
 #include <pthread.h>
 #include <sys/socket.h>
+#include <unistd.h>
 
 #include "sd-event.h"
 #include "sd-json.h"

src/test/test-vpick.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "fd-util.h"
 #include "fileio.h"
 #include "fs-util.h"

src/test/test-watch-pid.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <unistd.h>
+
 #include "manager.h"
 #include "process-util.h"
 #include "rm-rf.h"

src/timesync/timesyncd-manager.c

@@ -5,6 +5,7 @@
 #include <netinet/in.h>
 #include <netinet/ip.h>
 #include <resolv.h>
+#include <unistd.h>
 
 #include "sd-bus.h"
 #include "sd-daemon.h"

src/timesync/timesyncd.c

@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "sd-event.h"
 #include "sd-messages.h"

src/udev/udev-manager.c

@@ -2,6 +2,7 @@
 
 #include <poll.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 #include "sd-varlink.h"
 

src/udev/udev-spawn.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 
+#include <unistd.h>
+
 #include "sd-event.h"
 
 #include "build-path.h"

src/udev/udev-watch.c

@@ -6,6 +6,7 @@
 
 #include <sys/signalfd.h>
 #include <sys/wait.h>
+#include <unistd.h>
 
 #include "alloc-util.h"
 #include "blockdev-util.h"