From dd0395b5654c52e982adf6d354db9c7fdcf4b6c7 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Wed, 4 Mar 2020 00:52:40 +0900
Subject: make namespace_flags_to_string() not return empty string

This improves the following debug log.

Before:
systemd[1162]: Restricting namespace to: .

After:
systemd[1162]: Restricting namespace to: n/a.
---
 src/core/dbus-util.h    | 3 ++-
 src/core/execute.c      | 2 +-
 src/shared/bus-util.c   | 2 +-
 src/shared/nsflags.c    | 6 ------
 src/test/test-seccomp.c | 2 +-
 5 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/src/core/dbus-util.h b/src/core/dbus-util.h
index a3316c6701..ec8c245fff 100644
--- a/src/core/dbus-util.h
+++ b/src/core/dbus-util.h
@@ -127,7 +127,8 @@ int bus_property_get_triggered_unit(sd_bus *bus, const char *path, const char *i
                 if (!UNIT_WRITE_FLAGS_NOOP(flags)) {                    \
                         *p = (cast_type) v;                             \
                         unit_write_settingf(u, flags, name,             \
-                                            "%s=%s", name, s);          \
+                                            "%s=%s",                    \
+                                            name, strempty(s));         \
                 }                                                       \
                                                                         \
                 return 1;                                               \
diff --git a/src/core/execute.c b/src/core/execute.c
index 76e1b28d37..4595bb12dc 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -4881,7 +4881,7 @@ void exec_context_dump(const ExecContext *c, FILE* f, const char *prefix) {
                 r = namespace_flags_to_string(c->restrict_namespaces, &s);
                 if (r >= 0)
                         fprintf(f, "%sRestrictNamespaces: %s\n",
-                                prefix, s);
+                                prefix, strna(s));
         }
 
         if (c->network_namespace_path)
diff --git a/src/shared/bus-util.c b/src/shared/bus-util.c
index 15bc0ed71b..8e6a6e2ce2 100644
--- a/src/shared/bus-util.c
+++ b/src/shared/bus-util.c
@@ -406,7 +406,7 @@ static int bus_print_property(const char *name, const char *expected_value, sd_b
                                 if (r < 0)
                                         return r;
 
-                                result = s;
+                                result = strempty(s);
                         }
 
                         bus_print_property_value(name, expected_value, value, result);
diff --git a/src/shared/nsflags.c b/src/shared/nsflags.c
index 8cc2d0873d..4dbd18b868 100644
--- a/src/shared/nsflags.c
+++ b/src/shared/nsflags.c
@@ -65,12 +65,6 @@ int namespace_flags_to_string(unsigned long flags, char **ret) {
                         return -ENOMEM;
         }
 
-        if (!s) {
-                s = strdup("");
-                if (!s)
-                        return -ENOMEM;
-        }
-
         *ret = TAKE_PTR(s);
 
         return 0;
diff --git a/src/test/test-seccomp.c b/src/test/test-seccomp.c
index 75566199e3..67900d85e9 100644
--- a/src/test/test-seccomp.c
+++ b/src/test/test-seccomp.c
@@ -190,7 +190,7 @@ static void test_restrict_namespace(void) {
 
         log_info("/* %s */", __func__);
 
-        assert_se(namespace_flags_to_string(0, &s) == 0 && streq(s, ""));
+        assert_se(namespace_flags_to_string(0, &s) == 0 && isempty(s));
         s = mfree(s);
         assert_se(namespace_flags_to_string(CLONE_NEWNS, &s) == 0 && streq(s, "mnt"));
         s = mfree(s);
-- 
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