manager: write net/unix/max_dgram_qlen sysctl as fixed string

src/basic/constants.h

@@ -43,7 +43,7 @@
 #define DEFAULT_EXIT_USEC (30*USEC_PER_SEC)
 
 /* The default value for the net.unix.max_dgram_qlen sysctl */
-#define DEFAULT_UNIX_MAX_DGRAM_QLEN 512UL
+#define DEFAULT_UNIX_MAX_DGRAM_QLEN 512
 
 #define SIGNALS_CRASH_HANDLER SIGSEGV,SIGILL,SIGFPE,SIGBUS,SIGQUIT,SIGABRT
 #define SIGNALS_IGNORE SIGPIPE

src/core/main.c

@@ -1405,8 +1405,7 @@ static int bump_unix_max_dgram_qlen(void) {
         if (v >= DEFAULT_UNIX_MAX_DGRAM_QLEN)
                 return 0;
 
-        r = write_string_filef("/proc/sys/net/unix/max_dgram_qlen", WRITE_STRING_FILE_DISABLE_BUFFER,
-                               "%lu", DEFAULT_UNIX_MAX_DGRAM_QLEN);
+        r = sysctl_write("net/unix/max_dgram_qlen", STRINGIFY(DEFAULT_UNIX_MAX_DGRAM_QLEN));
         if (r < 0)
                 return log_full_errno(IN_SET(r, -EROFS, -EPERM, -EACCES) ? LOG_DEBUG : LOG_WARNING, r,
                                       "Failed to bump AF_UNIX datagram queue length, ignoring: %m");