util-lib: share plymouth client code

Let's add a new "plymouth-util.c" module with helpers for talking to
plymouth. We so far had three places for this, let's unify the code
doing this a bit.

src/shared/ask-password-api.c

@@ -20,7 +20,6 @@
 
 #include "alloc-util.h"
 #include "ask-password-api.h"
-#include "constants.h"
 #include "creds-util.h"
 #include "fd-util.h"
 #include "fileio.h"
@@ -36,6 +35,7 @@
 #include "missing_syscall.h"
 #include "mkdir-label.h"
 #include "nulstr-util.h"
+#include "plymouth-util.h"
 #include "process-util.h"
 #include "random-util.h"
 #include "signal-util.h"
@@ -211,7 +211,6 @@ int ask_password_plymouth(
                 const char *flag_file,
                 char ***ret) {
 
-        static const union sockaddr_union sa = PLYMOUTH_SOCKET;
         _cleanup_close_ int fd = -EBADF, notify = -EBADF;
         _cleanup_free_ char *packet = NULL;
         ssize_t k;
@@ -238,12 +237,9 @@ int ask_password_plymouth(
                         return -errno;
         }
 
-        fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        fd = plymouth_connect(SOCK_NONBLOCK);
         if (fd < 0)
-                return -errno;
-
-        if (connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un)) < 0)
-                return -errno;
+                return fd;
 
         if (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED)) {
                 packet = strdup("c");

src/shared/meson.build

@@ -137,6 +137,7 @@ shared_sources = files(
         'pcrextend-util.c',
         'pe-binary.c',
         'pkcs11-util.c',
+        'plymouth-util.c',
         'pretty-print.c',
         'ptyfwd.c',
         'qrcode-util.c',

src/shared/plymouth-util.c

@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "fd-util.h"
+#include "io-util.h"
+#include "plymouth-util.h"
+#include "socket-util.h"
+
+int plymouth_connect(int flags) {
+        static const union sockaddr_union sa = {
+                .un.sun_family = AF_UNIX,
+                .un.sun_path = "\0/org/freedesktop/plymouthd",
+        };
+        _cleanup_close_ int fd = -EBADF;
+
+        fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|flags, 0);
+        if (fd < 0)
+                return -errno;
+
+        if (connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un)) < 0)
+                return -errno;
+
+        return TAKE_FD(fd);
+}
+
+int plymouth_send_raw(const void *raw, size_t size, int flags) {
+        _cleanup_close_ int fd = -EBADF;
+
+        fd = plymouth_connect(flags);
+        if (fd < 0)
+                return fd;
+
+        return loop_write(fd, raw, size);
+}

src/shared/plymouth-util.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <sys/types.h>
+
+#include "errno-util.h"
+
+int plymouth_connect(int flags);
+int plymouth_send_raw(const void *raw, size_t size, int flags);
+
+static inline bool ERRNO_IS_NO_PLYMOUTH(int r) {
+        return IN_SET(abs(r), EAGAIN, ENOENT) || ERRNO_IS_DISCONNECT(r);
+}