core:namespace: simplify mount calculation

Move out mount calculation on its own function. Actually the logic is
smart enough to later drop nop and duplicates mounts, this change
improves code readability.
---
 src/core/namespace.c | 47 ++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 36 insertions(+), 11 deletions(-)

1 files changed, 34 insertions, 12 deletions

diff --git a/src/core/namespace.c b/src/core/namespace.c
index 13f6aeba51..8aa8b83c88 100644
--- a/src/core/namespace.c
+++ b/src/core/namespace.c
@@ -515,6 +515,32 @@ static int chase_all_symlinks(const char *root_directory, BindMount *m, unsigned
         return 0;
 }
 
+static unsigned namespace_calculate_mounts(
+                char** read_write_paths,
+                char** read_only_paths,
+                char** inaccessible_paths,
+                const char* tmp_dir,
+                const char* var_tmp_dir,
+                bool private_dev,
+                bool protect_sysctl,
+                bool protect_cgroups,
+                ProtectHome protect_home,
+                ProtectSystem protect_system) {
+
+        return !!tmp_dir + !!var_tmp_dir +
+                strv_length(read_write_paths) +
+                strv_length(read_only_paths) +
+                strv_length(inaccessible_paths) +
+                private_dev +
+                (protect_sysctl ? ELEMENTSOF(protect_kernel_tunables_table) : 0) +
+                (protect_cgroups ? 1 : 0) +
+                (protect_home != PROTECT_HOME_NO || protect_system == PROTECT_SYSTEM_STRICT ? 3 : 0) +
+                (protect_system == PROTECT_SYSTEM_STRICT ?
+                 (2 + !private_dev + !protect_sysctl) :
+                 ((protect_system != PROTECT_SYSTEM_NO ? 3 : 0) +
+                  (protect_system == PROTECT_SYSTEM_FULL ? 1 : 0)));
+}
+
 int setup_namespace(
                 const char* root_directory,
                 char** read_write_paths,
@@ -537,19 +563,15 @@ int setup_namespace(
         if (mount_flags == 0)
                 mount_flags = MS_SHARED;
 
-        n = !!tmp_dir + !!var_tmp_dir +
-                strv_length(read_write_paths) +
-                strv_length(read_only_paths) +
-                strv_length(inaccessible_paths) +
-                private_dev +
-                (protect_sysctl ? ELEMENTSOF(protect_kernel_tunables_table) : 0) +
-                (protect_cgroups ? 1 : 0) +
-                (protect_home != PROTECT_HOME_NO || protect_system == PROTECT_SYSTEM_STRICT ? 3 : 0) +
-                (protect_system == PROTECT_SYSTEM_STRICT ?
-                 (2 + !private_dev + !protect_sysctl) :
-                 ((protect_system != PROTECT_SYSTEM_NO ? 3 : 0) +
-                  (protect_system == PROTECT_SYSTEM_FULL ? 1 : 0)));
+        n = namespace_calculate_mounts(read_write_paths,
+                                       read_only_paths,
+                                       inaccessible_paths,
+                                       tmp_dir, var_tmp_dir,
+                                       private_dev, protect_sysctl,
+                                       protect_cgroups, protect_home,
+                                       protect_system);
 
+        /* Set mount slave mode */
         if (root_directory || n > 0)
                 make_slave = true;