nsenter: use macros to access the nsfiles array

This change implements macros to access the nsfiles array, resulting
in a slight reduction in code.

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/sys-utils/nsenter.c b/sys-utils/nsenter.c
index 53c3641fbbdcefc54bcfb13b5bba015a66ade4a4..e60cc4d12fb888a0a839d9aa5a2a079803350a9a 100644 (file)
--- a/sys-utils/nsenter.c
+++ b/sys-utils/nsenter.c
@@ -130,6 +130,30 @@ static int env_fd = -1;
 static int uid_gid_fd = -1;
 static int cgroup_procs_fd = -1;
 
+static inline struct namespace_file *__next_nsfile(struct namespace_file *n, int namespaces, bool enabled)
+{
+       if (!n)
+               n = namespace_files;
+       else if (n->nstype != 0)
+               n++;
+
+       for ( ; n && n->nstype; n++) {
+               if (namespaces && !(n->nstype & namespaces))
+                       continue;
+               if (enabled && !n->enabled)
+                       continue;
+               return n;
+       }
+
+       return NULL;
+}
+
+#define next_nsfile(_n, _ns)           __next_nsfile(_n, _ns, 0)
+#define next_enabled_nsfile(_n, _ns)   __next_nsfile(_n, _ns, 1)
+
+#define get_nsfile(_ns)                        __next_nsfile(NULL, _ns, 0)
+#define get_enabled_nsfile(_ns)                __next_nsfile(NULL, _ns, 1)
+
 static void open_parent_user_ns_fd(void)
 {
        struct namespace_file *nsfile = NULL;
@@ -199,51 +223,43 @@ static void disable_nsfile(struct namespace_file *n)
 /* Enable namespace; optionally open @path if not NULL. */
 static void enable_namespace(int nstype, const char *path)
 {
-       struct namespace_file *nsfile;
+       struct namespace_file *nsfile = get_nsfile(nstype);
 
-       for (nsfile = namespace_files; nsfile->nstype; nsfile++) {
-               if (nstype != nsfile->nstype)
-                       continue;
+       if (nsfile)
                enable_nsfile(nsfile, path);
-               return;
-       }
-       /* This should never happen */
-       assert(nsfile->nstype);
+       else
+               assert(nsfile);
 }
 
 static void disable_namespaces(int namespaces)
 {
-       struct namespace_file *n;
+       struct namespace_file *n = NULL;
 
-       for (n = namespace_files; n->nstype; n++) {
-               if (!(namespaces & n->nstype))
-                       continue;
+       while ((n = next_enabled_nsfile(n, namespaces)))
                disable_nsfile(n);
-       }
 }
 
 /* Returns mask of all enabled namespaces */
 static int get_namespaces(void)
 {
-       struct namespace_file *n;
+       struct namespace_file *n = NULL;
        int mask = 0;
 
-       for (n = namespace_files; n->nstype; n++) {
-               if (n->enabled)
-                       mask |= n->nstype;
-       }
+       while ((n = next_enabled_nsfile(n, 0)))
+               mask |= n->nstype;
        return mask;
 }
 
 static int get_namespaces_without_fd(void)
 {
-       struct namespace_file *n;
+       struct namespace_file *n = NULL;
        int mask = 0;
 
-       for (n = namespace_files; n->nstype; n++) {
-               if (n->enabled && n->fd < 0)
+       while ((n = next_enabled_nsfile(n, 0))) {
+               if (n->fd < 0)
                        mask |= n->nstype;
        }
+
        return mask;
 }
 
@@ -251,13 +267,9 @@ static int get_namespaces_without_fd(void)
  * if they have not been opened yet. */
 static void open_namespaces(int namespaces)
 {
-       struct namespace_file *n;
+       struct namespace_file *n = NULL;
 
-       for (n = namespace_files; n->nstype; n++) {
-               if (!n->enabled)
-                       continue;
-               if (!(n->nstype & namespaces))
-                       continue;
+       while ((n = next_enabled_nsfile(n, namespaces))) {
                if (n->fd < 0)
                        open_target_fd(&n->fd, n->name, NULL);
        }
@@ -278,20 +290,21 @@ static int do_setns(int fd, int ns, const char *name, bool ignore_errors)
 
 static void enter_namespaces(int pid_fd, int namespaces, bool ignore_errors)
 {
-       struct namespace_file *n;
+       struct namespace_file *n =  NULL;
 
        if (pid_fd) {
                int ns = 0;
-               for (n = namespace_files; n->nstype; n++) {
-                       if (n->enabled && (n->nstype & namespaces) && n->fd < 0)
+               while ((n = next_enabled_nsfile(n, namespaces))) {
+                       if (n->fd < 0)
                                ns |= n->nstype;
                }
                if (ns && do_setns(pid_fd, ns, NULL, ignore_errors) == 0)
                        disable_namespaces(ns);
        }
 
-       for (n = namespace_files; n->nstype; n++) {
-               if (!n->enabled || !(n->nstype & namespaces) || n->fd < 0)
+       n = NULL;
+       while ((n = next_enabled_nsfile(n, namespaces))) {
+               if (n->fd < 0)
                        continue;
                if (do_setns(n->fd, n->nstype, n->name, ignore_errors) == 0)
                        disable_nsfile(n);
@@ -304,10 +317,7 @@ static void open_target_sk_netns(int pid, int sock_fd)
        struct stat sb;
        int pidfd, sk, nsfd;
 
-       for (nsfile = namespace_files; nsfile->nstype; nsfile++) {
-               if (nsfile->nstype == CLONE_NEWNET)
-                       break;
-       }
+       nsfile = get_nsfile(CLONE_NEWNET);
        assert(nsfile->nstype);
 
        pidfd = pidfd_open(pid, 0);
@@ -500,7 +510,6 @@ int main(int argc, char *argv[])
        };
        int excl_st[ARRAY_SIZE(excl)] = UL_EXCL_STATUS_INIT;
 
-       struct namespace_file *nsfile;
        int c, namespaces = 0, setgroups_nerrs = 0, preserve_cred = 0;
        bool do_rd = false, do_wd = false, do_uid = false, force_uid = false,
             do_gid = false, force_gid = false, do_env = false, do_all = false,
@@ -641,14 +650,11 @@ int main(int argc, char *argv[])
 #endif
 
        if (do_all) {
-               for (nsfile = namespace_files; nsfile->nstype; nsfile++) {
-                       if (nsfile->enabled)
-                               continue;       /* namespace already specified */
-
-                       if (!is_usable_namespace(namespace_target_pid, nsfile))
+               struct namespace_file *n = NULL;
+               while ((n = next_nsfile(n, 0))) {
+                       if (n->enabled || !is_usable_namespace(namespace_target_pid, n))
                                continue;
-
-                       enable_nsfile(nsfile, NULL);
+                       enable_nsfile(n, NULL);
                }
        }