Merge pull request #12217 from keszybz/unlocked-operations

Refactor how we do unlocked file operations

52 files changed, 294 insertions, 326 deletions

diff --git a/coccinelle/fopen-unlocked.cocci b/coccinelle/fopen-unlocked.cocci
new file mode 100644
index 0000000000..7870f8ccea
--- /dev/null
+++ b/coccinelle/fopen-unlocked.cocci
@@ -0,0 +1,71 @@
+@@
+expression f, path, options;
+@@
+- f = fopen(path, options);
+- if (!f)
+-       return -errno;
+- (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
++ r = fopen_unlocked(path, options, &f);
++ if (r < 0)
++       return r;
+@@
+expression f, path, options;
+@@
+- f = fopen(path, options);
+- if (!f) {
+-       if (errno == ENOENT)
+-            return -ESRCH;
+-       return -errno;
+- }
+- (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
++ r = fopen_unlocked(path, options, &f);
++ if (r == -ENOENT)
++     return -ESRCH;
++ if (r < 0)
++       return r;
+@@
+expression f, path, options;
+@@
+- f = fopen(path, options);
+- if (!f)
+-       return errno == ENOENT ? -ESRCH : -errno;
+- (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
++ r = fopen_unlocked(path, options, &f);
++ if (r == -ENOENT)
++     return -ESRCH;
++ if (r < 0)
++       return r;
+@@
+expression f, path, p;
+@@
+  r = fopen_temporary(path, &f, &p);
+  if (r < 0)
+    return ...;
+- (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+@@
+expression f, g, path, p;
+@@
+  r = fopen_temporary_label(path, g, &f, &p);
+  if (r < 0)
+    return ...;
+- (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+@@
+expression f, fd, options;
+@@
+- f = fdopen(fd, options);
++ r = fdopen_unlocked(fd, options, &f);
++ if (r < 0) {
+- if (!f) {
+        ...
+-       return -errno;
++       return r;
+  }
+- (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+@@
+expression f, buf, sz;
+@@
+- f = open_memstream(&buf, &sz);
++ f = open_memstream_unlocked(&buf, &sz);
+  if (!f)
+        return ...;
+- (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
index fc28109db8..210089688b 100644
--- a/src/basic/cgroup-util.c
+++ b/src/basic/cgroup-util.c
@@ -6,7 +6,6 @@
 #include <limits.h>
 #include <signal.h>
 #include <stddef.h>
-#include <stdio_ext.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
@@ -1016,11 +1015,11 @@ int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
         }
 
         fs = procfs_file_alloca(pid, "cgroup");
-        f = fopen(fs, "re");
-        if (!f)
-                return errno == ENOENT ? -ESRCH : -errno;
-
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+        r = fopen_unlocked(fs, "re", &f);
+        if (r == -ENOENT)
+                return -ESRCH;
+        if (r < 0)
+                return r;
 
         for (;;) {
                 _cleanup_free_ char *line = NULL;
@@ -2442,17 +2441,13 @@ int cg_kernel_controllers(Set **ret) {
         if (!controllers)
                 return -ENOMEM;
 
-        f = fopen("/proc/cgroups", "re");
-        if (!f) {
-                if (errno == ENOENT) {
-                        *ret = NULL;
-                        return 0;
-                }
-
-                return -errno;
+        r = fopen_unlocked("/proc/cgroups", "re", &f);
+        if (r == -ENOENT) {
+                *ret = NULL;
+                return 0;
         }
-
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+        if (r < 0)
+                return r;
 
         /* Ignore the header line */
         (void) read_line(f, (size_t) -1, NULL);
diff --git a/src/basic/env-file.c b/src/basic/env-file.c
index a1f1308a54..83767b0a24 100644
--- a/src/basic/env-file.c
+++ b/src/basic/env-file.c
@@ -1,7 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
-#include <stdio_ext.h>
-
 #include "alloc-util.h"
 #include "env-file.h"
 #include "env-util.h"
@@ -545,7 +543,6 @@ int write_env_file(const char *fname, char **l) {
         if (r < 0)
                 return r;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
         (void) fchmod_umask(fileno(f), 0644);
 
         STRV_FOREACH(i, l)
diff --git a/src/basic/fileio.c b/src/basic/fileio.c
index 9ab2f501c7..85a49b1f9e 100644
--- a/src/basic/fileio.c
+++ b/src/basic/fileio.c
@@ -29,6 +29,52 @@
 
 #define READ_FULL_BYTES_MAX (4U*1024U*1024U)
 
+int fopen_unlocked(const char *path, const char *options, FILE **ret) {
+        assert(ret);
+
+        FILE *f = fopen(path, options);
+        if (!f)
+                return -errno;
+
+        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+
+        *ret = f;
+        return 0;
+}
+
+int fdopen_unlocked(int fd, const char *options, FILE **ret) {
+        assert(ret);
+
+        FILE *f = fdopen(fd, options);
+        if (!f)
+                return -errno;
+
+        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+
+        *ret = f;
+        return 0;
+}
+
+FILE* open_memstream_unlocked(char **ptr, size_t *sizeloc) {
+        FILE *f = open_memstream(ptr, sizeloc);
+        if (!f)
+                return NULL;
+
+        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+
+        return f;
+}
+
+FILE* fmemopen_unlocked(void *buf, size_t size, const char *mode) {
+        FILE *f = fmemopen(buf, size, mode);
+        if (!f)
+                return NULL;
+
+        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+
+        return f;
+}
+
 int write_string_stream_ts(
                 FILE *f,
                 const char *line,
@@ -95,7 +141,6 @@ static int write_string_file_atomic(
         if (r < 0)
                 return r;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
         (void) fchmod_umask(fileno(f), 0644);
 
         r = write_string_stream_ts(f, line, flags, ts);
@@ -141,11 +186,9 @@ int write_string_file_ts(
                 assert(!ts);
 
         if (flags & WRITE_STRING_FILE_CREATE) {
-                f = fopen(fn, "we");
-                if (!f) {
-                        r = -errno;
+                r = fopen_unlocked(fn, "we", &f);
+                if (r < 0)
                         goto fail;
-                }
         } else {
                 int fd;
 
@@ -157,16 +200,13 @@ int write_string_file_ts(
                         goto fail;
                 }
 
-                f = fdopen(fd, "w");
-                if (!f) {
-                        r = -errno;
+                r = fdopen_unlocked(fd, "w", &f);
+                if (r < 0) {
                         safe_close(fd);
                         goto fail;
                 }
         }
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
         if (flags & WRITE_STRING_FILE_DISABLE_BUFFER)
                 setvbuf(f, NULL, _IONBF, 0);
 
@@ -213,15 +253,14 @@ int write_string_filef(
 
 int read_one_line_file(const char *fn, char **line) {
         _cleanup_fclose_ FILE *f = NULL;
+        int r;
 
         assert(fn);
         assert(line);
 
-        f = fopen(fn, "re");
-        if (!f)
-                return -errno;
-
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+        r = fopen_unlocked(fn, "re", &f);
+        if (r < 0)
+                return r;
 
         return read_line(f, LONG_LINE_MAX, line);
 }
@@ -230,6 +269,7 @@ int verify_file(const char *fn, const char *blob, bool accept_extra_nl) {
         _cleanup_fclose_ FILE *f = NULL;
         _cleanup_free_ char *buf = NULL;
         size_t l, k;
+        int r;
 
         assert(fn);
         assert(blob);
@@ -243,11 +283,9 @@ int verify_file(const char *fn, const char *blob, bool accept_extra_nl) {
         if (!buf)
                 return -ENOMEM;
 
-        f = fopen(fn, "re");
-        if (!f)
-                return -errno;
-
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+        r = fopen_unlocked(fn, "re", &f);
+        if (r < 0)
+                return r;
 
         /* We try to read one byte more than we need, so that we know whether we hit eof */
         errno = 0;
@@ -390,15 +428,14 @@ finalize:
 
 int read_full_file_full(const char *filename, ReadFullFileFlags flags, char **contents, size_t *size) {
         _cleanup_fclose_ FILE *f = NULL;
+        int r;
 
         assert(filename);
         assert(contents);
 
-        f = fopen(filename, "re");
-        if (!f)
-                return -errno;
-
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+        r = fopen_unlocked(filename, "re", &f);
+        if (r < 0)
+                return r;
 
         return read_full_stream_full(f, filename, flags, contents, size);
 }
diff --git a/src/basic/fileio.h b/src/basic/fileio.h
index 760e738688..ffe900b486 100644
--- a/src/basic/fileio.h
+++ b/src/basic/fileio.h
@@ -33,6 +33,11 @@ typedef enum {
         READ_FULL_FILE_UNBASE64 = 1 << 1,
 } ReadFullFileFlags;
 
+int fopen_unlocked(const char *path, const char *options, FILE **ret);
+int fdopen_unlocked(int fd, const char *options, FILE **ret);
+FILE* open_memstream_unlocked(char **ptr, size_t *sizeloc);
+FILE* fmemopen_unlocked(void *buf, size_t size, const char *mode);
+
 int write_string_stream_ts(FILE *f, const char *line, WriteStringFileFlags flags, struct timespec *ts);
 static inline int write_string_stream(FILE *f, const char *line, WriteStringFileFlags flags) {
         return write_string_stream_ts(f, line, flags, NULL);
diff --git a/src/basic/mountpoint-util.c b/src/basic/mountpoint-util.c
index 1e946a0bb6..5ac9293167 100644
--- a/src/basic/mountpoint-util.c
+++ b/src/basic/mountpoint-util.c
@@ -2,7 +2,6 @@
 
 #include <errno.h>
 #include <fcntl.h>
-#include <stdio_ext.h>
 #include <sys/mount.h>
 
 #include "alloc-util.h"
@@ -378,11 +377,9 @@ int dev_is_devtmpfs(void) {
         if (r < 0)
                 return r;
 
-        proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
-        if (!proc_self_mountinfo)
-                return -errno;
-
-        (void) __fsetlocking(proc_self_mountinfo, FSETLOCKING_BYCALLER);
+        r = fopen_unlocked("/proc/self/mountinfo", "re", &proc_self_mountinfo);
+        if (r < 0)
+                return r;
 
         for (;;) {
                 _cleanup_free_ char *line = NULL;
diff --git a/src/basic/process-util.c b/src/basic/process-util.c
index f773eeaffd..3dc3534e1a 100644
--- a/src/basic/process-util.c
+++ b/src/basic/process-util.c
@@ -8,7 +8,6 @@
 #include <signal.h>
 #include <stdbool.h>
 #include <stdio.h>
-#include <stdio_ext.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/mman.h>
@@ -106,7 +105,7 @@ int get_process_cmdline(pid_t pid, size_t max_length, bool comm_fallback, char *
         char *k;
         _cleanup_free_ char *ans = NULL;
         const char *p;
-        int c;
+        int c, r;
 
         assert(line);
         assert(pid >= 0);
@@ -121,15 +120,11 @@ int get_process_cmdline(pid_t pid, size_t max_length, bool comm_fallback, char *
          * comm_fallback is false). Returns 0 and sets *line otherwise. */
 
         p = procfs_file_alloca(pid, "cmdline");
-
-        f = fopen(p, "re");
-        if (!f) {
-                if (errno == ENOENT)
-                        return -ESRCH;
-                return -errno;
-        }
-
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+        r = fopen_unlocked(p, "re", &f);
+        if (r == -ENOENT)
+                return -ESRCH;
+        if (r < 0)
+                return r;
 
         if (max_length == 0) {
                 /* This is supposed to be a safety guard against runaway command lines. */
@@ -513,14 +508,11 @@ static int get_process_id(pid_t pid, const char *field, uid_t *uid) {
                 return -EINVAL;
 
         p = procfs_file_alloca(pid, "status");
-        f = fopen(p, "re");
-        if (!f) {
-                if (errno == ENOENT)
-                        return -ESRCH;
-                return -errno;
-        }
-
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+        r = fopen_unlocked(p, "re", &f);
+        if (r == -ENOENT)
+                return -ESRCH;
+        if (r < 0)
+                return r;
 
         for (;;) {
                 _cleanup_free_ char *line = NULL;
@@ -602,14 +594,11 @@ int get_process_environ(pid_t pid, char **env) {
 
         p = procfs_file_alloca(pid, "environ");
 
-        f = fopen(p, "re");
-        if (!f) {
-                if (errno == ENOENT)
-                        return -ESRCH;
-                return -errno;
-        }
-
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+        r = fopen_unlocked(p, "re", &f);
+        if (r == -ENOENT)
+                return -ESRCH;
+        if (r < 0)
+                return r;
 
         for (;;) {
                 char c;
@@ -895,15 +884,11 @@ int getenv_for_pid(pid_t pid, const char *field, char **ret) {
 
         path = procfs_file_alloca(pid, "environ");
 
-        f = fopen(path, "re");
-        if (!f) {
-                if (errno == ENOENT)
-                        return -ESRCH;
-
-                return -errno;
-        }
-
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+        r = fopen_unlocked(path, "re", &f);
+        if (r == -ENOENT)
+                return -ESRCH;
+        if (r < 0)
+                return r;
 
         l = strlen(field);
         for (;;) {
diff --git a/src/basic/string-util.c b/src/basic/string-util.c
index 5001a2be3a..779048904a 100644
--- a/src/basic/string-util.c
+++ b/src/basic/string-util.c
@@ -4,7 +4,6 @@
 #include <stdarg.h>
 #include <stdint.h>
 #include <stdio.h>
-#include <stdio_ext.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -761,23 +760,20 @@ char *strip_tab_ansi(char **ibuf, size_t *_isz, size_t highlight[2]) {
          * 2. Strips ANSI color sequences (a subset of CSI), i.e. ESC '[' … 'm' sequences
          * 3. Strips ANSI operating system sequences (CSO), i.e. ESC ']' … BEL sequences
          *
-         * Everything else will be left as it is. In particular other ANSI sequences are left as they are, as are any
-         * other special characters. Truncated ANSI sequences are left-as is too. This call is supposed to suppress the
-         * most basic formatting noise, but nothing else.
+         * Everything else will be left as it is. In particular other ANSI sequences are left as they are, as
+         * are any other special characters. Truncated ANSI sequences are left-as is too. This call is
+         * supposed to suppress the most basic formatting noise, but nothing else.
          *
          * Why care for CSO sequences? Well, to undo what terminal_urlify() and friends generate. */
 
         isz = _isz ? *_isz : strlen(*ibuf);
 
-        f = open_memstream(&obuf, &osz);
+        /* Note we turn off internal locking on f for performance reasons. It's safe to do so since we
+         * created f here and it doesn't leave our scope. */
+        f = open_memstream_unlocked(&obuf, &osz);
         if (!f)
                 return NULL;
 
-        /* Note we turn off internal locking on f for performance reasons.  It's safe to do so since we created f here
-         * and it doesn't leave our scope. */
-
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
         for (i = *ibuf; i < *ibuf + isz + 1; i++) {
 
                 switch (state) {
diff --git a/src/basic/tmpfile-util.c b/src/basic/tmpfile-util.c
index bc92d6a6de..e77af7659f 100644
--- a/src/basic/tmpfile-util.c
+++ b/src/basic/tmpfile-util.c
@@ -1,9 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
+#include <stdio.h>
 #include <sys/mman.h>
 
 #include "alloc-util.h"
 #include "fd-util.h"
+#include "fileio.h"
 #include "fs-util.h"
 #include "hexdecoct.h"
 #include "macro.h"
@@ -37,12 +39,15 @@ int fopen_temporary(const char *path, FILE **_f, char **_temp_path) {
                 return -errno;
         }
 
-        f = fdopen(fd, "w");
-        if (!f) {
-                unlink_noerrno(t);
+        /* This assumes that returned FILE object is short-lived and used within the same single-threaded
+         * context and never shared externally, hence locking is not necessary. */
+
+        r = fdopen_unlocked(fd, "w", &f);
+        if (r < 0) {
+                unlink(t);
                 free(t);
                 safe_close(fd);
-                return -errno;
+                return r;
         }
 
         *_f = f;
diff --git a/src/busctl/busctl.c b/src/busctl/busctl.c
index c8125c6606..02f12dc701 100644
--- a/src/busctl/busctl.c
+++ b/src/busctl/busctl.c
@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
 #include <getopt.h>
-#include <stdio_ext.h>
 
 #include "sd-bus.h"
 
@@ -997,12 +996,10 @@ static int introspect(int argc, char **argv, void *userdata) {
                         if (r < 0)
                                 return bus_log_parse_error(r);
 
-                        mf = open_memstream(&buf, &sz);
+                        mf = open_memstream_unlocked(&buf, &sz);
                         if (!mf)
                                 return log_oom();
 
-                        (void) __fsetlocking(mf, FSETLOCKING_BYCALLER);
-
                         r = format_cmdline(reply, mf, false);
                         if (r < 0)
                                 return bus_log_parse_error(r);
diff --git a/src/core/dbus-cgroup.c b/src/core/dbus-cgroup.c
index 4615aeaf66..7a5e440e9c 100644
--- a/src/core/dbus-cgroup.c
+++ b/src/core/dbus-cgroup.c
@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
 #include <arpa/inet.h>
-#include <stdio_ext.h>
 
 #include "af-list.h"
 #include "alloc-util.h"
@@ -821,12 +820,10 @@ int bus_cgroup_set_property(
 
                         unit_invalidate_cgroup(u, CGROUP_MASK_IO);
 
-                        f = open_memstream(&buf, &size);
+                        f = open_memstream_unlocked(&buf, &size);
                         if (!f)
                                 return -ENOMEM;
 
-                        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
                         fprintf(f, "%s=\n", name);
                         LIST_FOREACH(device_limits, a, c->io_device_limits)
                                         if (a->limits[iol_type] != cgroup_io_limit_defaults[iol_type])
@@ -903,12 +900,10 @@ int bus_cgroup_set_property(
 
                         unit_invalidate_cgroup(u, CGROUP_MASK_IO);
 
-                        f = open_memstream(&buf, &size);
+                        f = open_memstream_unlocked(&buf, &size);
                         if (!f)
                                 return -ENOMEM;
 
-                        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
                         fputs("IODeviceWeight=\n", f);
                         LIST_FOREACH(device_weights, a, c->io_device_weights)
                                 fprintf(f, "IODeviceWeight=%s %" PRIu64 "\n", a->path, a->weight);
@@ -982,12 +977,10 @@ int bus_cgroup_set_property(
 
                         unit_invalidate_cgroup(u, CGROUP_MASK_IO);
 
-                        f = open_memstream(&buf, &size);
+                        f = open_memstream_unlocked(&buf, &size);
                         if (!f)
                                 return -ENOMEM;
 
-                        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
                         fputs("IODeviceLatencyTargetSec=\n", f);
                         LIST_FOREACH(device_latencies, a, c->io_device_latencies)
                                 fprintf(f, "IODeviceLatencyTargetSec=%s %s\n",
@@ -1077,12 +1070,10 @@ int bus_cgroup_set_property(
 
                         unit_invalidate_cgroup(u, CGROUP_MASK_BLKIO);
 
-                        f = open_memstream(&buf, &size);
+                        f = open_memstream_unlocked(&buf, &size);
                         if (!f)
                                 return -ENOMEM;
 
-                        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
                         if (read) {
                                 fputs("BlockIOReadBandwidth=\n", f);
                                 LIST_FOREACH(device_bandwidths, a, c->blockio_device_bandwidths)
@@ -1167,12 +1158,10 @@ int bus_cgroup_set_property(
 
                         unit_invalidate_cgroup(u, CGROUP_MASK_BLKIO);
 
-                        f = open_memstream(&buf, &size);
+                        f = open_memstream_unlocked(&buf, &size);
                         if (!f)
                                 return -ENOMEM;
 
-                        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
                         fputs("BlockIODeviceWeight=\n", f);
                         LIST_FOREACH(device_weights, a, c->blockio_device_weights)
                                 fprintf(f, "BlockIODeviceWeight=%s %" PRIu64 "\n", a->path, a->weight);
@@ -1275,12 +1264,10 @@ int bus_cgroup_set_property(
 
                         unit_invalidate_cgroup(u, CGROUP_MASK_DEVICES);
 
-                        f = open_memstream(&buf, &size);
+                        f = open_memstream_unlocked(&buf, &size);
                         if (!f)
                                 return -ENOMEM;
 
-                        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
                         fputs("DeviceAllow=\n", f);
                         LIST_FOREACH(device_allow, a, c->device_allow)
                                 fprintf(f, "DeviceAllow=%s %s%s%s\n", a->path, a->r ? "r" : "", a->w ? "w" : "", a->m ? "m" : "");
@@ -1390,12 +1377,10 @@ int bus_cgroup_set_property(
                                 *list = ip_address_access_free_all(*list);
 
                         unit_invalidate_cgroup_bpf(u);
-                        f = open_memstream(&buf, &size);
+                        f = open_memstream_unlocked(&buf, &size);
                         if (!f)
                                 return -ENOMEM;
 
-                        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
                         fputs(name, f);
                         fputs("=\n", f);
 
diff --git a/src/core/dbus-execute.c b/src/core/dbus-execute.c
index 5532d1ada9..48a2ebc5ef 100644
--- a/src/core/dbus-execute.c
+++ b/src/core/dbus-execute.c
@@ -2,7 +2,6 @@
 
 #include <sys/mount.h>
 #include <sys/prctl.h>
-#include <stdio_ext.h>
 
 #if HAVE_SECCOMP
 #include <seccomp.h>
@@ -958,12 +957,10 @@ int bus_set_transient_exec_command(
                 if (n == 0)
                         *exec_command = exec_command_free_list(*exec_command);
 
-                f = open_memstream(&buf, &size);
+                f = open_memstream_unlocked(&buf, &size);
                 if (!f)
                         return -ENOMEM;
 
-                (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
                 fputs("ExecStart=\n", f);
 
                 LIST_FOREACH(command, c, *exec_command) {
@@ -2015,12 +2012,10 @@ int bus_exec_context_set_transient_property(
                 if (r < 0)
                         return r;
 
-                f = open_memstream(&joined, &size);
+                f = open_memstream_unlocked(&joined, &size);
                 if (!f)
                         return -ENOMEM;
 
-                (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
                 fputs("EnvironmentFile=\n", f);
 
                 STRV_FOREACH(i, c->environment_files) {
diff --git a/src/core/dbus-service.c b/src/core/dbus-service.c
index 0f563a6625..4e6709c42e 100644
--- a/src/core/dbus-service.c
+++ b/src/core/dbus-service.c
@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
-#include <stdio_ext.h>
 #include <fcntl.h>
 
 #include "alloc-util.h"
diff --git a/src/core/manager.c b/src/core/manager.c
index 24559a45f3..66e3403d2c 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -4,7 +4,6 @@
 #include <fcntl.h>
 #include <linux/kd.h>
 #include <signal.h>
-#include <stdio_ext.h>
 #include <string.h>
 #include <sys/epoll.h>
 #include <sys/inotify.h>
@@ -2111,12 +2110,10 @@ int manager_get_dump_string(Manager *m, char **ret) {
         assert(m);
         assert(ret);
 
-        f = open_memstream(&dump, &size);
+        f = open_memstream_unlocked(&dump, &size);
         if (!f)
                 return -errno;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
         manager_dump(m, f, NULL);
 
         r = fflush_and_check(f);
diff --git a/src/core/smack-setup.c b/src/core/smack-setup.c
index cd7fb01416..b95e6239d4 100644
--- a/src/core/smack-setup.c
+++ b/src/core/smack-setup.c
@@ -9,7 +9,6 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
-#include <stdio_ext.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
@@ -26,12 +25,36 @@
 
 #if ENABLE_SMACK
 
-static int write_access2_rules(const char* srcdir) {
+static int fdopen_unlocked_at(int dfd, const char *dir, const char *name, int *status, FILE **ret_file) {
+        int fd, r;
+        FILE *f;
+
+        fd = openat(dfd, name, O_RDONLY|O_CLOEXEC);
+        if (fd < 0) {
+                if (*status == 0)
+                        *status = -errno;
+
+                return log_warning_errno(errno, "Failed to open \"%s/%s\": %m", dir, name);
+        }
+
+        r = fdopen_unlocked(fd, "r", &f);
+        if (r < 0) {
+                if (*status == 0)
+                        *status = r;
+
+                safe_close(fd);
+                return log_error_errno(r, "Failed to open \"%s/%s\": %m", dir, name);
+        }
+
+        *ret_file = f;
+        return 0;
+}
+
+static int write_access2_rules(const char *srcdir) {
         _cleanup_close_ int load2_fd = -1, change_fd = -1;
         _cleanup_closedir_ DIR *dir = NULL;
         struct dirent *entry;
-        int dfd = -1;
-        int r = 0;
+        int dfd = -1, r = 0;
 
         load2_fd = open("/sys/fs/smackfs/load2", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
         if (load2_fd < 0)  {
@@ -59,28 +82,13 @@ static int write_access2_rules(const char* srcdir) {
         assert(dfd >= 0);
 
         FOREACH_DIRENT(entry, dir, return 0) {
-                int fd;
                 _cleanup_fclose_ FILE *policy = NULL;
 
                 if (!dirent_is_file(entry))
                         continue;
 
-                fd = openat(dfd, entry->d_name, O_RDONLY|O_CLOEXEC);
-                if (fd < 0) {
-                        if (r == 0)
-                                r = -errno;
-                        log_warning_errno(errno, "Failed to open '%s': %m", entry->d_name);
+                if (fdopen_unlocked_at(dfd, srcdir, entry->d_name, &r, &policy) < 0)
                         continue;
-                }
-
-                policy = fdopen(fd, "r");
-                if (!policy) {
-                        if (r == 0)
-                                r = -errno;
-                        safe_close(fd);
-                        log_error_errno(errno, "Failed to open '%s': %m", entry->d_name);
-                        continue;
-                }
 
                 /* load2 write rules in the kernel require a line buffered stream */
                 for (;;) {
@@ -115,12 +123,11 @@ static int write_access2_rules(const char* srcdir) {
         return r;
 }
 
-static int write_cipso2_rules(const char* srcdir) {
+static int write_cipso2_rules(const char *srcdir) {
         _cleanup_close_ int cipso2_fd = -1;
         _cleanup_closedir_ DIR *dir = NULL;
         struct dirent *entry;
-        int dfd = -1;
-        int r = 0;
+        int dfd = -1, r = 0;
 
         cipso2_fd = open("/sys/fs/smackfs/cipso2", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
         if (cipso2_fd < 0)  {
@@ -141,28 +148,13 @@ static int write_cipso2_rules(const char* srcdir) {
         assert(dfd >= 0);
 
         FOREACH_DIRENT(entry, dir, return 0) {
-                int fd;
                 _cleanup_fclose_ FILE *policy = NULL;
 
                 if (!dirent_is_file(entry))
                         continue;
 
-                fd = openat(dfd, entry->d_name, O_RDONLY|O_CLOEXEC);
-                if (fd < 0) {
-                        if (r == 0)
-                                r = -errno;
-                        log_error_errno(errno, "Failed to open '%s': %m", entry->d_name);
-                        continue;
-                }
-
-                policy = fdopen(fd, "r");
-                if (!policy) {
-                        if (r == 0)
-                                r = -errno;
-                        safe_close(fd);
-                        log_error_errno(errno, "Failed to open '%s': %m", entry->d_name);
+                if (fdopen_unlocked_at(dfd, srcdir, entry->d_name, &r, &policy) < 0)
                         continue;
-                }
 
                 /* cipso2 write rules in the kernel require a line buffered stream */
                 for (;;) {
@@ -191,12 +183,11 @@ static int write_cipso2_rules(const char* srcdir) {
         return r;
 }
 
-static int write_netlabel_rules(const char* srcdir) {
+static int write_netlabel_rules(const char *srcdir) {
         _cleanup_fclose_ FILE *dst = NULL;
         _cleanup_closedir_ DIR *dir = NULL;
         struct dirent *entry;
-        int dfd = -1;
-        int r = 0;
+        int dfd = -1, r = 0;
 
         dst = fopen("/sys/fs/smackfs/netlabel", "we");
         if (!dst)  {
@@ -217,27 +208,10 @@ static int write_netlabel_rules(const char* srcdir) {
         assert(dfd >= 0);
 
         FOREACH_DIRENT(entry, dir, return 0) {
-                int fd;
                 _cleanup_fclose_ FILE *policy = NULL;
 
-                fd = openat(dfd, entry->d_name, O_RDONLY|O_CLOEXEC);
-                if (fd < 0) {
-                        if (r == 0)
-                                r = -errno;
-                        log_warning_errno(errno, "Failed to open %s: %m", entry->d_name);
+                if (fdopen_unlocked_at(dfd, srcdir, entry->d_name, &r, &policy) < 0)
                         continue;
-                }
-
-                policy = fdopen(fd, "r");
-                if (!policy) {
-                        if (r == 0)
-                                r = -errno;
-                        safe_close(fd);
-                        log_error_errno(errno, "Failed to open %s: %m", entry->d_name);
-                        continue;
-                }
-
-                (void) __fsetlocking(policy, FSETLOCKING_BYCALLER);
 
                 /* load2 write rules in the kernel require a line buffered stream */
                 for (;;) {
diff --git a/src/coredump/coredump.c b/src/coredump/coredump.c
index 023701646b..ac7b972026 100644
--- a/src/coredump/coredump.c
+++ b/src/coredump/coredump.c
@@ -2,7 +2,6 @@
 
 #include <errno.h>
 #include <stdio.h>
-#include <stdio_ext.h>
 #include <sys/prctl.h>
 #include <sys/xattr.h>
 #include <unistd.h>
@@ -530,12 +529,10 @@ static int compose_open_fds(pid_t pid, char **open_fds) {
         if (proc_fdinfo_fd < 0)
                 return -errno;
 
-        stream = open_memstream(&buffer, &size);
+        stream = open_memstream_unlocked(&buffer, &size);
         if (!stream)
                 return -ENOMEM;
 
-        (void) __fsetlocking(stream, FSETLOCKING_BYCALLER);
-
         FOREACH_DIRENT(dent, proc_fd_dir, return -errno) {
                 _cleanup_fclose_ FILE *fdinfo = NULL;
                 _cleanup_free_ char *fdname = NULL;
diff --git a/src/coredump/stacktrace.c b/src/coredump/stacktrace.c
index ab1ac12a23..66b2ec8cca 100644
--- a/src/coredump/stacktrace.c
+++ b/src/coredump/stacktrace.c
@@ -2,11 +2,11 @@
 
 #include <dwarf.h>
 #include <elfutils/libdwfl.h>
-#include <stdio_ext.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include "alloc-util.h"
+#include "fileio.h"
 #include "fd-util.h"
 #include "format-util.h"
 #include "macro.h"
@@ -126,12 +126,10 @@ int coredump_make_stack_trace(int fd, const char *executable, char **ret) {
         if (lseek(fd, 0, SEEK_SET) == (off_t) -1)
                 return -errno;
 
-        c.f = open_memstream(&buf, &sz);
+        c.f = open_memstream_unlocked(&buf, &sz);
         if (!c.f)
                 return -ENOMEM;
 
-        (void) __fsetlocking(c.f, FSETLOCKING_BYCALLER);
-
         elf_version(EV_CURRENT);
 
         c.elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
diff --git a/src/cryptsetup/cryptsetup-generator.c b/src/cryptsetup/cryptsetup-generator.c
index e9b21689c7..fbb443c6e2 100644
--- a/src/cryptsetup/cryptsetup-generator.c
+++ b/src/cryptsetup/cryptsetup-generator.c
@@ -2,7 +2,6 @@
 
 #include <errno.h>
 #include <fcntl.h>
-#include <stdio_ext.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 
@@ -479,15 +478,13 @@ static int add_crypttab_devices(void) {
         if (!arg_read_crypttab)
                 return 0;
 
-        f = fopen("/etc/crypttab", "re");
-        if (!f) {
+        r = fopen_unlocked("/etc/crypttab", "re", &f);
+        if (r < 0) {
                 if (errno != ENOENT)
                         log_error_errno(errno, "Failed to open /etc/crypttab: %m");
                 return 0;
         }
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
         if (fstat(fileno(f), &st) < 0) {
                 log_error_errno(errno, "Failed to stat /etc/crypttab: %m");
                 return 0;
diff --git a/src/fstab-generator/fstab-generator.c b/src/fstab-generator/fstab-generator.c
index d35f2f993e..28ae48d551 100644
--- a/src/fstab-generator/fstab-generator.c
+++ b/src/fstab-generator/fstab-generator.c
@@ -5,7 +5,6 @@
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
-#include <stdio_ext.h>
 
 #include "alloc-util.h"
 #include "fd-util.h"
diff --git a/src/fuzz/fuzz-bus-message.c b/src/fuzz/fuzz-bus-message.c
index 9842c62a6f..aca82edad9 100644
--- a/src/fuzz/fuzz-bus-message.c
+++ b/src/fuzz/fuzz-bus-message.c
@@ -1,13 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
-#include <errno.h>
-#include <stdio.h>
-
 #include "alloc-util.h"
 #include "bus-dump.h"
 #include "bus-message.h"
 #include "env-util.h"
 #include "fd-util.h"
+#include "fileio.h"
 #include "fuzz.h"
 
 int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
@@ -36,7 +34,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         TAKE_PTR(buffer);
 
         if (getenv_bool("SYSTEMD_FUZZ_OUTPUT") <= 0)
-                assert_se(g = open_memstream(&out, &out_size));
+                assert_se(g = open_memstream_unlocked(&out, &out_size));
 
         bus_message_dump(m, g ?: stdout, BUS_MESSAGE_DUMP_WITH_HEADER);
 
diff --git a/src/fuzz/fuzz-env-file.c b/src/fuzz/fuzz-env-file.c
index 3c8ffaa7b2..d945dfc02c 100644
--- a/src/fuzz/fuzz-env-file.c
+++ b/src/fuzz/fuzz-env-file.c
@@ -1,9 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
-#include <errno.h>
+#include <stdio.h>
 
 #include "alloc-util.h"
 #include "env-file.h"
+#include "fileio.h"
 #include "fd-util.h"
 #include "fuzz.h"
 #include "strv.h"
@@ -15,7 +16,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         if (size == 0 || size > 65535)
                 return 0;
 
-        f = fmemopen((char*) data, size, "re");
+        f = fmemopen_unlocked((char*) data, size, "re");
         assert_se(f);
 
         /* We don't want to fill the logs with messages about parse errors.
diff --git a/src/fuzz/fuzz-hostname-util.c b/src/fuzz/fuzz-hostname-util.c
index deaf8112ba..2130a4a811 100644
--- a/src/fuzz/fuzz-hostname-util.c
+++ b/src/fuzz/fuzz-hostname-util.c
@@ -1,9 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
-#include <errno.h>
-
 #include "alloc-util.h"
 #include "fd-util.h"
+#include "fileio.h"
 #include "fuzz.h"
 #include "hostname-util.h"
 
@@ -14,7 +13,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         if (size == 0)
                 return 0;
 
-        f = fmemopen((char*) data, size, "re");
+        f = fmemopen_unlocked((char*) data, size, "re");
         assert_se(f);
 
         /* We don't want to fill the logs with messages about parse errors.
diff --git a/src/fuzz/fuzz-json.c b/src/fuzz/fuzz-json.c
index 3aa9d089e6..ce7b69dbb9 100644
--- a/src/fuzz/fuzz-json.c
+++ b/src/fuzz/fuzz-json.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
 #include "alloc-util.h"
+#include "fileio.h"
 #include "fd-util.h"
 #include "fuzz.h"
 #include "json.h"
@@ -14,13 +15,13 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         if (size == 0)
                 return 0;
 
-        f = fmemopen((char*) data, size, "re");
+        f = fmemopen_unlocked((char*) data, size, "re");
         assert_se(f);
 
         if (json_parse_file(f, NULL, &v, NULL, NULL) < 0)
                 return 0;
 
-        g = open_memstream(&out, &out_size);
+        g = open_memstream_unlocked(&out, &out_size);
         assert_se(g);
 
         json_variant_dump(v, 0, g, NULL);
diff --git a/src/fuzz/fuzz-nspawn-oci.c b/src/fuzz/fuzz-nspawn-oci.c
index f7b59f13ba..004230eafe 100644
--- a/src/fuzz/fuzz-nspawn-oci.c
+++ b/src/fuzz/fuzz-nspawn-oci.c
@@ -1,9 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
-#include <errno.h>
-
 #include "alloc-util.h"
 #include "fd-util.h"
+#include "fileio.h"
 #include "fuzz.h"
 #include "nspawn-oci.h"
 
@@ -14,7 +13,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         if (size == 0)
                 return 0;
 
-        f = fmemopen((char*) data, size, "re");
+        f = fmemopen_unlocked((char*) data, size, "re");
         assert_se(f);
 
         /* We don't want to fill the logs with messages about parse errors.
diff --git a/src/fuzz/fuzz-nspawn-settings.c b/src/fuzz/fuzz-nspawn-settings.c
index 6c81eb773a..aa0a8225b4 100644
--- a/src/fuzz/fuzz-nspawn-settings.c
+++ b/src/fuzz/fuzz-nspawn-settings.c
@@ -1,9 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
-#include <errno.h>
-
 #include "alloc-util.h"
 #include "fd-util.h"
+#include "fileio.h"
 #include "fuzz.h"
 #include "nspawn-settings.h"
 
@@ -14,7 +13,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         if (size == 0)
                 return 0;
 
-        f = fmemopen((char*) data, size, "re");
+        f = fmemopen_unlocked((char*) data, size, "re");
         assert_se(f);
 
         /* We don't want to fill the logs with messages about parse errors.
diff --git a/src/fuzz/fuzz-unit-file.c b/src/fuzz/fuzz-unit-file.c
index 84b1ea66ec..d3993cf123 100644
--- a/src/fuzz/fuzz-unit-file.c
+++ b/src/fuzz/fuzz-unit-file.c
@@ -24,7 +24,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         if (size == 0)
                 return 0;
 
-        f = fmemopen((char*) data, size, "re");
+        f = fmemopen_unlocked((char*) data, size, "re");
         assert_se(f);
 
         if (read_line(f, LINE_MAX, &p) < 0)
@@ -75,7 +75,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
                             config_item_perf_lookup, load_fragment_gperf_lookup,
                             CONFIG_PARSE_ALLOW_INCLUDE, u);
 
-        g = open_memstream(&out, &out_size);
+        g = open_memstream_unlocked(&out, &out_size);
         assert_se(g);
 
         unit_dump(u, g, "");
diff --git a/src/journal/journal-qrcode.c b/src/journal/journal-qrcode.c
index 35d6ec4593..678654f773 100644
--- a/src/journal/journal-qrcode.c
+++ b/src/journal/journal-qrcode.c
@@ -4,9 +4,9 @@
 #include <qrencode.h>
 #include <stdbool.h>
 #include <stdio.h>
-#include <stdio_ext.h>
 #include <stdlib.h>
 
+#include "fileio.h"
 #include "journal-qrcode.h"
 #include "macro.h"
 
@@ -45,12 +45,10 @@ int print_qr_code(
         assert(seed);
         assert(seed_size > 0);
 
-        f = open_memstream(&url, &url_size);
+        f = open_memstream_unlocked(&url, &url_size);
         if (!f)
                 return -ENOMEM;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
         fputs("fss://", f);
 
         for (i = 0; i < seed_size; i++) {
diff --git a/src/libsystemd-network/sd-dhcp-lease.c b/src/libsystemd-network/sd-dhcp-lease.c
index a16314a9d3..c089b4278b 100644
--- a/src/libsystemd-network/sd-dhcp-lease.c
+++ b/src/libsystemd-network/sd-dhcp-lease.c
@@ -6,7 +6,6 @@
 #include <arpa/inet.h>
 #include <errno.h>
 #include <stdio.h>
-#include <stdio_ext.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
@@ -832,7 +831,6 @@ int dhcp_lease_save(sd_dhcp_lease *lease, const char *lease_file) {
         if (r < 0)
                 goto fail;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
         (void) fchmod(fileno(f), 0644);
 
         fprintf(f,
diff --git a/src/libsystemd/sd-bus/bus-introspect.c b/src/libsystemd/sd-bus/bus-introspect.c
index 29a5ef715e..022eddb10f 100644
--- a/src/libsystemd/sd-bus/bus-introspect.c
+++ b/src/libsystemd/sd-bus/bus-introspect.c
@@ -1,7 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
-#include <stdio_ext.h>
-
 #include "bus-internal.h"
 #include "bus-introspect.h"
 #include "bus-objects.h"
@@ -18,12 +16,10 @@ int introspect_begin(struct introspect *i, bool trusted) {
         zero(*i);
         i->trusted = trusted;
 
-        i->f = open_memstream(&i->introspection, &i->size);
+        i->f = open_memstream_unlocked(&i->introspection, &i->size);
         if (!i->f)
                 return -ENOMEM;
 
-        (void) __fsetlocking(i->f, FSETLOCKING_BYCALLER);
-
         fputs(BUS_INTROSPECT_DOCTYPE
               "<node>\n", i->f);
 
diff --git a/src/libsystemd/sd-bus/bus-match.c b/src/libsystemd/sd-bus/bus-match.c
index 266dd7f1df..14204eeb6b 100644
--- a/src/libsystemd/sd-bus/bus-match.c
+++ b/src/libsystemd/sd-bus/bus-match.c
@@ -1,7 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
-#include <stdio_ext.h>
-
 #include "alloc-util.h"
 #include "bus-internal.h"
 #include "bus-match.h"
@@ -861,12 +859,10 @@ char *bus_match_to_string(struct bus_match_component *components, unsigned n_com
 
         assert(components);
 
-        f = open_memstream(&buffer, &size);
+        f = open_memstream_unlocked(&buffer, &size);
         if (!f)
                 return NULL;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
         for (i = 0; i < n_components; i++) {
                 char buf[32];
 
diff --git a/src/libsystemd/sd-bus/test-bus-marshal.c b/src/libsystemd/sd-bus/test-bus-marshal.c
index 1e9810ce4f..ade16e532d 100644
--- a/src/libsystemd/sd-bus/test-bus-marshal.c
+++ b/src/libsystemd/sd-bus/test-bus-marshal.c
@@ -20,6 +20,7 @@
 #include "bus-util.h"
 #include "escape.h"
 #include "fd-util.h"
+#include "fileio.h"
 #include "log.h"
 #include "tests.h"
 #include "util.h"
@@ -189,7 +190,7 @@ int main(int argc, char *argv[]) {
 
         bus_message_dump(m, stdout, BUS_MESSAGE_DUMP_WITH_HEADER);
 
-        ms = open_memstream(&first, &first_size);
+        ms = open_memstream_unlocked(&first, &first_size);
         bus_message_dump(m, ms, 0);
         fflush(ms);
         assert_se(!ferror(ms));
@@ -245,7 +246,7 @@ int main(int argc, char *argv[]) {
         bus_message_dump(m, stdout, BUS_MESSAGE_DUMP_WITH_HEADER);
 
         fclose(ms);
-        ms = open_memstream(&second, &second_size);
+        ms = open_memstream_unlocked(&second, &second_size);
         bus_message_dump(m, ms, 0);
         fflush(ms);
         assert_se(!ferror(ms));
@@ -351,7 +352,7 @@ int main(int argc, char *argv[]) {
         assert_se(r >= 0);
 
         fclose(ms);
-        ms = open_memstream(&third, &third_size);
+        ms = open_memstream_unlocked(&third, &third_size);
         bus_message_dump(copy, ms, 0);
         fflush(ms);
         assert_se(!ferror(ms));
diff --git a/src/locale/keymap-util.c b/src/locale/keymap-util.c
index b8bd181c16..e238e5a124 100644
--- a/src/locale/keymap-util.c
+++ b/src/locale/keymap-util.c
@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
 #include <errno.h>
-#include <stdio_ext.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -423,7 +422,6 @@ int x11_write_data(Context *c) {
         if (r < 0)
                 return r;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
         (void) fchmod(fileno(f), 0644);
 
         fputs("# Written by systemd-localed(8), read by systemd-localed and Xorg. It's\n"
diff --git a/src/login/logind-seat.c b/src/login/logind-seat.c
index b4904c37d5..f5ffb68238 100644
--- a/src/login/logind-seat.c
+++ b/src/login/logind-seat.c
@@ -2,7 +2,6 @@
 
 #include <errno.h>
 #include <fcntl.h>
-#include <stdio_ext.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <unistd.h>
@@ -97,7 +96,6 @@ int seat_save(Seat *s) {
         if (r < 0)
                 goto fail;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
         (void) fchmod(fileno(f), 0644);
 
         fprintf(f,
diff --git a/src/login/logind-session.c b/src/login/logind-session.c
index 3d3bc8ab1c..f1efeb0e01 100644
--- a/src/login/logind-session.c
+++ b/src/login/logind-session.c
@@ -5,7 +5,6 @@
 #include <linux/kd.h>
 #include <linux/vt.h>
 #include <signal.h>
-#include <stdio_ext.h>
 #include <string.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
@@ -214,7 +213,6 @@ int session_save(Session *s) {
         if (r < 0)
                 goto fail;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
         (void) fchmod(fileno(f), 0644);
 
         fprintf(f,
diff --git a/src/login/logind-user.c b/src/login/logind-user.c
index 045b6f0e17..8356a9089a 100644
--- a/src/login/logind-user.c
+++ b/src/login/logind-user.c
@@ -3,7 +3,6 @@
 #include <errno.h>
 #include <string.h>
 #include <unistd.h>
-#include <stdio_ext.h>
 
 #include "alloc-util.h"
 #include "bus-common-errors.h"
@@ -162,7 +161,6 @@ static int user_save_internal(User *u) {
         if (r < 0)
                 goto fail;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
         (void) fchmod(fileno(f), 0644);
 
         fprintf(f,
diff --git a/src/machine/machine.c b/src/machine/machine.c
index 84454ddd86..b916d038d7 100644
--- a/src/machine/machine.c
+++ b/src/machine/machine.c
@@ -3,7 +3,6 @@
 #include <errno.h>
 #include <string.h>
 #include <unistd.h>
-#include <stdio_ext.h>
 #include <sys/stat.h>
 
 #include "sd-messages.h"
@@ -126,7 +125,6 @@ int machine_save(Machine *m) {
         if (r < 0)
                 goto fail;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
         (void) fchmod(fileno(f), 0644);
 
         fprintf(f,
diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
index 3e334c8d29..4846b13a8b 100644
--- a/src/network/networkd-link.c
+++ b/src/network/networkd-link.c
@@ -4,7 +4,6 @@
 #include <linux/if.h>
 #include <linux/can/netlink.h>
 #include <unistd.h>
-#include <stdio_ext.h>
 
 #include "alloc-util.h"
 #include "bus-util.h"
@@ -4034,7 +4033,6 @@ int link_save(Link *link) {
         if (r < 0)
                 goto fail;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
         (void) fchmod(fileno(f), 0644);
 
         fprintf(f,
diff --git a/src/network/networkd-manager.c b/src/network/networkd-manager.c
index 9075b0a14b..677f66a478 100644
--- a/src/network/networkd-manager.c
+++ b/src/network/networkd-manager.c
@@ -3,7 +3,6 @@
 #include <sys/socket.h>
 #include <linux/if.h>
 #include <linux/fib_rules.h>
-#include <stdio_ext.h>
 #include <unistd.h>
 
 #include "sd-daemon.h"
@@ -1189,7 +1188,6 @@ static int manager_save(Manager *m) {
         if (r < 0)
                 return r;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
         (void) fchmod(fileno(f), 0644);
 
         fprintf(f,
diff --git a/src/portable/portable.c b/src/portable/portable.c
index 9b6cc21d2c..1017864b37 100644
--- a/src/portable/portable.c
+++ b/src/portable/portable.c
@@ -1,7 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
-#include <stdio_ext.h>
-
 #include "bus-common-errors.h"
 #include "bus-error.h"
 #include "conf-files.h"
@@ -1091,12 +1089,10 @@ static int test_chroot_dropin(
                 return log_debug_errno(errno, "Failed to open %s/%s: %m", where, p);
         }
 
-        f = fdopen(fd, "r");
-        if (!f)
-                return log_debug_errno(errno, "Failed to convert file handle: %m");
-        fd = -1;
-
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
+        r = fdopen_unlocked(fd, "r", &f);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to convert file handle: %m");
+        TAKE_FD(fd);
 
         r = read_line(f, LONG_LINE_MAX, &line);
         if (r < 0)
diff --git a/src/portable/portablectl.c b/src/portable/portablectl.c
index bb6cebdf16..2c59f04eb5 100644
--- a/src/portable/portablectl.c
+++ b/src/portable/portablectl.c
@@ -12,6 +12,7 @@
 #include "dirent-util.h"
 #include "env-file.h"
 #include "fd-util.h"
+#include "fileio.h"
 #include "format-table.h"
 #include "fs-util.h"
 #include "locale-util.h"
@@ -272,10 +273,9 @@ static int inspect_image(int argc, char *argv[], void *userdata) {
                 nl = true;
         } else {
                 _cleanup_free_ char *pretty_portable = NULL, *pretty_os = NULL;
-
                 _cleanup_fclose_ FILE *f;
 
-                f = fmemopen((void*) data, sz, "re");
+                f = fmemopen_unlocked((void*) data, sz, "re");
                 if (!f)
                         return log_error_errno(errno, "Failed to open /etc/os-release buffer: %m");
 
diff --git a/src/resolve/resolved-dns-dnssec.c b/src/resolve/resolved-dns-dnssec.c
index a5ded5ada2..18e253bea3 100644
--- a/src/resolve/resolved-dns-dnssec.c
+++ b/src/resolve/resolved-dns-dnssec.c
@@ -1,9 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
-#include <stdio_ext.h>
-
 #if HAVE_GCRYPT
-#include <gcrypt.h>
+#  include <gcrypt.h>
 #endif
 
 #include "alloc-util.h"
@@ -803,10 +801,9 @@ int dnssec_verify_rrset(
         /* Bring the RRs into canonical order */
         typesafe_qsort(list, n, rr_compare);
 
-        f = open_memstream(&sig_data, &sig_size);
+        f = open_memstream_unlocked(&sig_data, &sig_size);
         if (!f)
                 return -ENOMEM;
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
 
         fwrite_uint16(f, rrsig->rrsig.type_covered);
         fwrite_uint8(f, rrsig->rrsig.algorithm);
diff --git a/src/resolve/resolved-link.c b/src/resolve/resolved-link.c
index 50f9309f10..f65ce64d17 100644
--- a/src/resolve/resolved-link.c
+++ b/src/resolve/resolved-link.c
@@ -2,7 +2,6 @@
 
 #include <net/if.h>
 #include <linux/if.h>
-#include <stdio_ext.h>
 #include <unistd.h>
 
 #include "sd-network.h"
@@ -1178,7 +1177,6 @@ int link_save_user(Link *l) {
         if (r < 0)
                 goto fail;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
         (void) fchmod(fileno(f), 0644);
 
         fputs("# This is private data. Do not parse.\n", f);
diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c
index 9b8239bd09..24a752e3bb 100644
--- a/src/resolve/resolved-manager.c
+++ b/src/resolve/resolved-manager.c
@@ -3,7 +3,6 @@
 #include <fcntl.h>
 #include <netinet/in.h>
 #include <poll.h>
-#include <stdio_ext.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -511,12 +510,10 @@ static int manager_sigusr1(sd_event_source *s, const struct signalfd_siginfo *si
         assert(si);
         assert(m);
 
-        f = open_memstream(&buffer, &size);
+        f = open_memstream_unlocked(&buffer, &size);
         if (!f)
                 return log_oom();
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
         LIST_FOREACH(scopes, scope, m->dns_scopes)
                 dns_scope_dump(scope, f);
 
diff --git a/src/resolve/resolved-resolv-conf.c b/src/resolve/resolved-resolv-conf.c
index 0435791ea0..dfc9a948e3 100644
--- a/src/resolve/resolved-resolv-conf.c
+++ b/src/resolve/resolved-resolv-conf.c
@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
 #include <resolv.h>
-#include <stdio_ext.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ -359,14 +358,12 @@ int manager_write_resolv_conf(Manager *m) {
         if (r < 0)
                 return log_warning_errno(r, "Failed to open private resolv.conf file for writing: %m");
 
-        (void) __fsetlocking(f_uplink, FSETLOCKING_BYCALLER);
         (void) fchmod(fileno(f_uplink), 0644);
 
         r = fopen_temporary_label(PRIVATE_STUB_RESOLV_CONF, PRIVATE_STUB_RESOLV_CONF, &f_stub, &temp_path_stub);
         if (r < 0)
                 return log_warning_errno(r, "Failed to open private stub-resolv.conf file for writing: %m");
 
-        (void) __fsetlocking(f_stub, FSETLOCKING_BYCALLER);
         (void) fchmod(fileno(f_stub), 0644);
 
         r = write_uplink_resolv_conf_contents(f_uplink, dns, domains);
diff --git a/src/shared/bootspec.c b/src/shared/bootspec.c
index 3bd14d7372..b2f8936038 100644
--- a/src/shared/bootspec.c
+++ b/src/shared/bootspec.c
@@ -298,7 +298,7 @@ static int boot_entry_load_unified(
         if (!k)
                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Path is not below root: %s", path);
 
-        f = fmemopen((void*) osrelease, strlen(osrelease), "r");
+        f = fmemopen_unlocked((void*) osrelease, strlen(osrelease), "r");
         if (!f)
                 return log_error_errno(errno, "Failed to open os-release buffer: %m");
 
diff --git a/src/shared/calendarspec.c b/src/shared/calendarspec.c
index d83e7962a6..6e318fa265 100644
--- a/src/shared/calendarspec.c
+++ b/src/shared/calendarspec.c
@@ -6,7 +6,6 @@
 #include <limits.h>
 #include <stddef.h>
 #include <stdio.h>
-#include <stdio_ext.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/mman.h>
@@ -330,12 +329,10 @@ int calendar_spec_to_string(const CalendarSpec *c, char **p) {
         assert(c);
         assert(p);
 
-        f = open_memstream(&buf, &sz);
+        f = open_memstream_unlocked(&buf, &sz);
         if (!f)
                 return -ENOMEM;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
         if (c->weekdays_bits > 0 && c->weekdays_bits <= BITS_WEEKDAYS) {
                 format_weekdays(f, c);
                 fputc(' ', f);
diff --git a/src/shared/format-table.c b/src/shared/format-table.c
index a5c0a99b08..74379e8c64 100644
--- a/src/shared/format-table.c
+++ b/src/shared/format-table.c
@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
 #include <ctype.h>
-#include <stdio_ext.h>
 
 #include "alloc-util.h"
 #include "fd-util.h"
@@ -1376,12 +1375,10 @@ int table_format(Table *t, char **ret) {
         size_t sz = 0;
         int r;
 
-        f = open_memstream(&buf, &sz);
+        f = open_memstream_unlocked(&buf, &sz);
         if (!f)
                 return -ENOMEM;
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
         r = table_print(t, f);
         if (r < 0)
                 return r;
diff --git a/src/shared/generator.c b/src/shared/generator.c
index ed7f037e91..403c2a6737 100644
--- a/src/shared/generator.c
+++ b/src/shared/generator.c
@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
 #include <errno.h>
-#include <stdio_ext.h>
 #include <unistd.h>
 
 #include "alloc-util.h"
@@ -30,23 +29,22 @@ int generator_open_unit_file(
 
         const char *unit;
         FILE *f;
+        int r;
 
         unit = strjoina(dest, "/", name);
 
-        f = fopen(unit, "wxe");
-        if (!f) {
-                if (source && errno == EEXIST)
-                        return log_error_errno(errno,
+        r = fopen_unlocked(unit, "wxe", &f);
+        if (r < 0) {
+                if (source && r == -EEXIST)
+                        return log_error_errno(r,
                                                "Failed to create unit file %s, as it already exists. Duplicate entry in %s?",
                                                unit, source);
                 else
-                        return log_error_errno(errno,
+                        return log_error_errno(r,
                                                "Failed to create unit file %s: %m",
                                                unit);
         }
 
-        (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
         fprintf(f,
                 "# Automatically generated by %s\n\n",
                 program_invocation_short_name);
diff --git a/src/shared/json.c b/src/shared/json.c
index db003a41a4..a1559bda4e 100644
--- a/src/shared/json.c
+++ b/src/shared/json.c
@@ -4,7 +4,6 @@
 #include <locale.h>
 #include <math.h>
 #include <stdarg.h>
-#include <stdio_ext.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
@@ -1558,12 +1557,10 @@ int json_variant_format(JsonVariant *v, JsonFormatFlags flags, char **ret) {
         {
                 _cleanup_fclose_ FILE *f = NULL;
 
-                f = open_memstream(&s, &sz);
+                f = open_memstream_unlocked(&s, &sz);
                 if (!f)
                         return -ENOMEM;
 
-                (void) __fsetlocking(f, FSETLOCKING_BYCALLER);
-
                 json_variant_dump(v, flags, f, NULL);
 
                 r = fflush_and_check(f);
diff --git a/src/shared/mount-util.c b/src/shared/mount-util.c
index 9987b6f80c..680c4522ad 100644
--- a/src/shared/mount-util.c
+++ b/src/shared/mount-util.c
@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
 #include <errno.h>
-#include <stdio_ext.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/mount.h>
@@ -40,13 +39,10 @@ int umount_recursive(const char *prefix, int flags) {
                 _cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
 
                 again = false;
-                r = 0;
 
-                proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
-                if (!proc_self_mountinfo)
-                        return -errno;
-
-                (void) __fsetlocking(proc_self_mountinfo, FSETLOCKING_BYCALLER);
+                r = fopen_unlocked("/proc/self/mountinfo", "re", &proc_self_mountinfo);
+                if (r < 0)
+                        return r;
 
                 for (;;) {
                         _cleanup_free_ char *path = NULL, *p = NULL;
@@ -302,12 +298,11 @@ int bind_remount_recursive_with_mountinfo(
 
 int bind_remount_recursive(const char *prefix, unsigned long new_flags, unsigned long flags_mask, char **blacklist) {
         _cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
+        int r;
 
-        proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
-        if (!proc_self_mountinfo)
-                return -errno;
-
-        (void) __fsetlocking(proc_self_mountinfo, FSETLOCKING_BYCALLER);
+        r = fopen_unlocked("/proc/self/mountinfo", "re", &proc_self_mountinfo);
+        if (r < 0)
+                return r;
 
         return bind_remount_recursive_with_mountinfo(prefix, new_flags, flags_mask, blacklist, proc_self_mountinfo);
 }
diff --git a/src/test/test-fileio.c b/src/test/test-fileio.c
index 2ff5b9a69d..cd1db3dd62 100644
--- a/src/test/test-fileio.c
+++ b/src/test/test-fileio.c
@@ -637,7 +637,7 @@ static void test_fgetc(void) {
         _cleanup_fclose_ FILE *f = NULL;
         char c;
 
-        f = fmemopen((void*) chars, sizeof(chars), "re");
+        f = fmemopen_unlocked((void*) chars, sizeof(chars), "re");
         assert_se(f);
 
         for (unsigned i = 0; i < sizeof(chars); i++) {
@@ -727,7 +727,7 @@ static void test_read_line_one_file(FILE *f) {
 static void test_read_line(void) {
         _cleanup_fclose_ FILE *f = NULL;
 
-        f = fmemopen((void*) buffer, sizeof(buffer), "re");
+        f = fmemopen_unlocked((void*) buffer, sizeof(buffer), "re");
         assert_se(f);
 
         test_read_line_one_file(f);
@@ -792,7 +792,7 @@ static void test_read_line4(void) {
                 _cleanup_fclose_ FILE *f = NULL;
                 _cleanup_free_ char *s = NULL;
 
-                assert_se(f = fmemopen((void*) eof_endings[i].string, eof_endings[i].length, "r"));
+                assert_se(f = fmemopen_unlocked((void*) eof_endings[i].string, eof_endings[i].length, "r"));
 
                 r = read_line(f, (size_t) -1, &s);
                 assert_se((size_t) r == eof_endings[i].length);
@@ -813,7 +813,7 @@ static void test_read_nul_string(void) {
         _cleanup_fclose_ FILE *f = NULL;
         _cleanup_free_ char *s = NULL;
 
-        assert_se(f = fmemopen((void*) test, sizeof(test)-1, "r"));
+        assert_se(f = fmemopen_unlocked((void*) test, sizeof(test)-1, "r"));
 
         assert_se(read_nul_string(f, LONG_LINE_MAX, &s) == 13 && streq_ptr(s, "string nr. 1"));
         s = mfree(s);
diff --git a/src/test/test-json.c b/src/test/test-json.c
index 9b8a2a9422..8bd6a7221c 100644
--- a/src/test/test-json.c
+++ b/src/test/test-json.c
@@ -4,6 +4,7 @@
 
 #include "alloc-util.h"
 #include "fd-util.h"
+#include "fileio.h"
 #include "json-internal.h"
 #include "json.h"
 #include "string-util.h"
@@ -358,7 +359,7 @@ static void test_source(void) {
                "%s"
                "--- original end ---\n", data);
 
-        assert_se(f = fmemopen((void*) data, strlen(data), "r"));
+        assert_se(f = fmemopen_unlocked((void*) data, strlen(data), "r"));
 
         assert_se(json_parse_file(f, "waldo", &v, NULL, NULL) >= 0);