attach: add get_attach_context_nsfds()

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/attach.c b/src/lxc/attach.c
index f44147d249fba804c123b4efddc4c8c96a044b32..af41afb05f4d6ecf2d270ce8348ddb5c9d7208f3 100644 (file)
--- a/src/lxc/attach.c
+++ b/src/lxc/attach.c
@@ -140,25 +140,6 @@ static int get_attach_context(struct attach_context *ctx,
        return 0;
 }
 
-static inline void lxc_proc_close_ns_fd(struct attach_context *ctx)
-{
-       for (int i = 0; i < LXC_NS_MAX; i++)
-               close_prot_errno_disarm(ctx->ns_fd[i]);
-}
-
-static void put_attach_context(struct attach_context *ctx)
-{
-       free_disarm(ctx->lsm_label);
-
-       if (ctx->container) {
-               lxc_container_put(ctx->container);
-               ctx->container = NULL;
-       }
-
-       lxc_proc_close_ns_fd(ctx);
-       free(ctx);
-}
-
 /**
  * in_same_namespace - Check whether two processes are in the same namespace.
  * @pid1 - PID of the first process.
@@ -207,6 +188,65 @@ static int in_same_namespace(pid_t pid1, pid_t pid2, const char *ns)
        return move_fd(ns_fd2);
 }
 
+static int get_attach_context_nsfds(struct attach_context *ctx,
+                                   lxc_attach_options_t *options)
+{
+
+       pid_t pid_self = lxc_raw_getpid();
+
+       for (int i = 0; i < LXC_NS_MAX; i++) {
+               int j;
+
+               if (options->namespaces & ns_info[i].clone_flag)
+                       ctx->ns_fd[i] = lxc_preserve_ns(ctx->init_pid, ns_info[i].proc_name);
+               else if (ctx->ns_inherited & ns_info[i].clone_flag)
+                       ctx->ns_fd[i] = in_same_namespace(pid_self, ctx->init_pid, ns_info[i].proc_name);
+               else
+                       continue;
+
+               if (ctx->ns_fd[i] >= 0)
+                       continue;
+
+               if (ctx->ns_fd[i] == -EINVAL) {
+                       DEBUG("Inheriting %s namespace from %d", ns_info[i].proc_name, pid_self);
+                       ctx->ns_inherited &= ~ns_info[i].clone_flag;
+                       continue;
+               }
+
+               /* We failed to preserve the namespace. */
+               SYSERROR("Failed to attach to %s namespace of %d", ns_info[i].proc_name, pid_self);
+
+               /* Close all already opened file descriptors before we return an
+                * error, so we don't leak them.
+                */
+               for (j = 0; j < i; j++)
+                       close_prot_errno_disarm(ctx->ns_fd[j]);
+
+               return -1;
+       }
+
+       return 0;
+}
+
+static inline void lxc_proc_close_ns_fd(struct attach_context *ctx)
+{
+       for (int i = 0; i < LXC_NS_MAX; i++)
+               close_prot_errno_disarm(ctx->ns_fd[i]);
+}
+
+static void put_attach_context(struct attach_context *ctx)
+{
+       free_disarm(ctx->lsm_label);
+
+       if (ctx->container) {
+               lxc_container_put(ctx->container);
+               ctx->container = NULL;
+       }
+
+       lxc_proc_close_ns_fd(ctx);
+       free(ctx);
+}
+
 static int lxc_attach_to_ns(pid_t pid, struct attach_context *ctx)
 {
        for (int i = 0; i < LXC_NS_MAX; i++) {
@@ -1056,39 +1096,10 @@ int lxc_attach(struct lxc_container *container, lxc_attach_exec_t exec_function,
                }
        }
 
-       pid = lxc_raw_getpid();
-
-       for (i = 0; i < LXC_NS_MAX; i++) {
-               int j;
-
-               if (options->namespaces & ns_info[i].clone_flag)
-                       ctx->ns_fd[i] = lxc_preserve_ns(ctx->init_pid, ns_info[i].proc_name);
-               else if (ctx->ns_inherited & ns_info[i].clone_flag)
-                       ctx->ns_fd[i] = in_same_namespace(pid, ctx->init_pid, ns_info[i].proc_name);
-               else
-                       continue;
-
-               if (ctx->ns_fd[i] >= 0)
-                       continue;
-
-               if (ctx->ns_fd[i] == -EINVAL) {
-                       DEBUG("Inheriting %s namespace from %d",
-                             ns_info[i].proc_name, pid);
-                       ctx->ns_inherited &= ~ns_info[i].clone_flag;
-                       continue;
-               }
-
-               /* We failed to preserve the namespace. */
-               SYSERROR("Failed to attach to %s namespace of %d",
-                        ns_info[i].proc_name, pid);
-
-               /* Close all already opened file descriptors before we return an
-                * error, so we don't leak them.
-                */
-               for (j = 0; j < i; j++)
-                       close(ctx->ns_fd[j]);
-
-               put_attach_context(ctx);
+       ret = get_attach_context_nsfds(ctx, options);
+       if (ret) {
+               ERROR("Failed to get namespace file descriptors");
+               lxc_container_put(container);
                return -1;
        }