diff options
| -rw-r--r-- | docs/ENVIRONMENT.md | 9 | ||||
| -rw-r--r-- | src/core/unit.c | 18 |
2 files changed, 27 insertions, 0 deletions
diff --git a/docs/ENVIRONMENT.md b/docs/ENVIRONMENT.md index 32bd9598b7..01ee065583 100644 --- a/docs/ENVIRONMENT.md +++ b/docs/ENVIRONMENT.md @@ -274,6 +274,15 @@ All tools: it is either set to `system` or `user` depending on whether the NSS/PAM module is called by systemd in `--system` or `--user` mode. +* `$SYSTEMD_SUPPORT_DEVICE`, `$SYSTEMD_SUPPORT_MOUNT`, `$SYSTEMD_SUPPORT_SWAP` - + can be set to `0` to mark respective unit type as unsupported. Generally, + having less units saves system resources so these options might be useful + for cases where we don't need to track given unit type, e.g. `--user` manager + often doesn't need to deal with device or swap units because they are + handled by the `--system` manager (PID 1). Note that setting certain unit + type as unsupported may not prevent loading some units of that type if they + are referenced by other units of another supported type. + `systemd-remount-fs`: * `$SYSTEMD_REMOUNT_ROOT_RW=1` — if set and no entry for the root directory diff --git a/src/core/unit.c b/src/core/unit.c index c8dc97b99d..29b07a6e7a 100644 --- a/src/core/unit.c +++ b/src/core/unit.c @@ -22,6 +22,7 @@ #include "dbus-unit.h" #include "dbus.h" #include "dropin.h" +#include "env-util.h" #include "escape.h" #include "execute.h" #include "fd-util.h" @@ -4781,11 +4782,28 @@ int unit_setup_dynamic_creds(Unit *u) { } bool unit_type_supported(UnitType t) { + static int8_t cache[_UNIT_TYPE_MAX] = {}; /* -1: disabled, 1: enabled: 0: don't know */ + int r; + if (_unlikely_(t < 0)) return false; if (_unlikely_(t >= _UNIT_TYPE_MAX)) return false; + if (cache[t] == 0) { + char *e; + + e = strjoina("SYSTEMD_SUPPORT_", unit_type_to_string(t)); + + r = getenv_bool(ascii_strupper(e)); + if (r < 0 && r != -ENXIO) + log_debug_errno(r, "Failed to parse $%s, ignoring: %m", e); + + cache[t] = r == 0 ? -1 : 1; + } + if (cache[t] < 0) + return false; + if (!unit_vtable[t]->supported) return true; |