Rename def.h to constants.h

The name "def.h" originates from before the rule of "no needless abbreviations"
was established. Let's rename the file to clarify that it contains a collection
of various semi-related constants.

src/basic/constants.h

@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#if !defined(HAS_FEATURE_MEMORY_SANITIZER)
+#  if defined(__has_feature)
+#    if __has_feature(memory_sanitizer)
+#      define HAS_FEATURE_MEMORY_SANITIZER 1
+#    endif
+#  endif
+#  if !defined(HAS_FEATURE_MEMORY_SANITIZER)
+#    define HAS_FEATURE_MEMORY_SANITIZER 0
+#  endif
+#endif
+
+#if !defined(HAS_FEATURE_ADDRESS_SANITIZER)
+#  ifdef __SANITIZE_ADDRESS__
+#      define HAS_FEATURE_ADDRESS_SANITIZER 1
+#  elif defined(__has_feature)
+#    if __has_feature(address_sanitizer)
+#      define HAS_FEATURE_ADDRESS_SANITIZER 1
+#    endif
+#  endif
+#  if !defined(HAS_FEATURE_ADDRESS_SANITIZER)
+#    define HAS_FEATURE_ADDRESS_SANITIZER 0
+#  endif
+#endif
+
+#define DEFAULT_TIMEOUT_USEC (90*USEC_PER_SEC)
+#define DEFAULT_RESTART_USEC (100*USEC_PER_MSEC)
+#define DEFAULT_CONFIRM_USEC (30*USEC_PER_SEC)
+
+/* We use an extra-long timeout for the reload. This is because a reload or reexec means generators are rerun
+ * which are timed out after DEFAULT_TIMEOUT_USEC. Let's use twice that time here, so that the generators can
+ * have their timeout, and for everything else there's the same time budget in place. */
+#define DAEMON_RELOAD_TIMEOUT_SEC (DEFAULT_TIMEOUT_USEC * 2)
+
+#define DEFAULT_START_LIMIT_INTERVAL (10*USEC_PER_SEC)
+#define DEFAULT_START_LIMIT_BURST 5
+
+/* The default time after which exit-on-idle services exit. This
+ * should be kept lower than the watchdog timeout, because otherwise
+ * the watchdog pings will keep the loop busy. */
+#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 SIGNALS_CRASH_HANDLER SIGSEGV,SIGILL,SIGFPE,SIGBUS,SIGQUIT,SIGABRT
+#define SIGNALS_IGNORE SIGPIPE
+
+#define NOTIFY_FD_MAX 768
+#define NOTIFY_BUFFER_MAX PIPE_BUF
+
+#if HAVE_SPLIT_USR
+#  define _CONF_PATHS_SPLIT_USR_NULSTR(n) "/lib/" n "\0"
+#  define _CONF_PATHS_SPLIT_USR(n) , "/lib/" n
+#else
+#  define _CONF_PATHS_SPLIT_USR_NULSTR(n)
+#  define _CONF_PATHS_SPLIT_USR(n)
+#endif
+
+/* Return a nulstr for a standard cascade of configuration paths,
+ * suitable to pass to conf_files_list_nulstr() or config_parse_many_nulstr()
+ * to implement drop-in directories for extending configuration
+ * files. */
+#define CONF_PATHS_NULSTR(n)                    \
+        "/etc/" n "\0"                          \
+        "/run/" n "\0"                          \
+        "/usr/local/lib/" n "\0"                \
+        "/usr/lib/" n "\0"                      \
+        _CONF_PATHS_SPLIT_USR_NULSTR(n)
+
+#define CONF_PATHS_USR(n)                       \
+        "/etc/" n,                              \
+        "/run/" n,                              \
+        "/usr/local/lib/" n,                    \
+        "/usr/lib/" n
+
+#define CONF_PATHS(n)                           \
+        CONF_PATHS_USR(n)                       \
+        _CONF_PATHS_SPLIT_USR(n)
+
+#define CONF_PATHS_USR_STRV(n)                  \
+        STRV_MAKE(CONF_PATHS_USR(n))
+
+#define CONF_PATHS_STRV(n)                      \
+        STRV_MAKE(CONF_PATHS(n))
+
+/* The limit for PID 1 itself (which is not inherited to children) */
+#define HIGH_RLIMIT_MEMLOCK (1024ULL*1024ULL*64ULL)
+
+/* Since kernel 5.16 the kernel default limit was raised to 8M. Let's adjust things on old kernels too, and
+ * in containers so that our children inherit that. */
+#define DEFAULT_RLIMIT_MEMLOCK (1024ULL*1024ULL*8ULL)
+
+#define PLYMOUTH_SOCKET {                                       \
+                .un.sun_family = AF_UNIX,                       \
+                .un.sun_path = "\0/org/freedesktop/plymouthd",  \
+        }
+
+/* Path where PID1 listens for varlink subscriptions from systemd-oomd to notify of changes in ManagedOOM settings. */
+#define VARLINK_ADDR_PATH_MANAGED_OOM_SYSTEM "/run/systemd/io.system.ManagedOOM"
+/* Path where systemd-oomd listens for varlink connections from user managers to report changes in ManagedOOM settings. */
+#define VARLINK_ADDR_PATH_MANAGED_OOM_USER "/run/systemd/oom/io.system.ManagedOOM"
+
+#define KERNEL_BASELINE_VERSION "4.15"