nspawn: add new .nspawn files for container settings

.nspawn fiels are simple settings files that may accompany container
images and directories and contain settings otherwise passed on the
nspawn command line. This provides an efficient way to attach execution
data directly to containers.

src/shared/conf-parser.c

@@ -24,7 +24,7 @@
 #include <errno.h>
 #include <stdlib.h>
 
-#include "conf-parser.h"
+#include "sd-messages.h"
 #include "conf-files.h"
 #include "util.h"
 #include "macro.h"
@@ -32,7 +32,8 @@
 #include "log.h"
 #include "utf8.h"
 #include "path-util.h"
-#include "sd-messages.h"
+#include "signal-util.h"
+#include "conf-parser.h"
 
 int config_item_table_lookup(
                 const void *table,
@@ -575,6 +576,39 @@ int config_parse_bool(const char* unit,
         return 0;
 }
 
+int config_parse_tristate(
+                const char* unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        int k, *t = data;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        /* A tristate is pretty much a boolean, except that it can
+         * also take the special value -1, indicating "uninitialized",
+         * much like NULL is for a pointer type. */
+
+        k = parse_boolean(rvalue);
+        if (k < 0) {
+                log_syntax(unit, LOG_ERR, filename, line, k, "Failed to parse boolean value, ignoring: %s", rvalue);
+                return 0;
+        }
+
+        *t = !!k;
+        return 0;
+}
+
 int config_parse_string(
                 const char *unit,
                 const char *filename,
@@ -802,3 +836,61 @@ int config_parse_log_level(
         *o = (*o & LOG_FACMASK) | x;
         return 0;
 }
+
+int config_parse_signal(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        int *sig = data, r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(sig);
+
+        r = signal_from_string_try_harder(rvalue);
+        if (r <= 0) {
+                log_syntax(unit, LOG_ERR, filename, line, EINVAL, "Failed to parse signal name, ignoring: %s", rvalue);
+                return 0;
+        }
+
+        *sig = r;
+        return 0;
+}
+
+int config_parse_personality(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        unsigned long *personality = data, p;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(personality);
+
+        p = personality_from_string(rvalue);
+        if (p == PERSONALITY_INVALID) {
+                log_syntax(unit, LOG_ERR, filename, line, EINVAL, "Failed to parse personality, ignoring: %s", rvalue);
+                return 0;
+        }
+
+        *personality = p;
+        return 0;
+}