container: Set primary process to 1 via LISTEN_PID by default if user…

… configuration is missing

Adds a new field to context listen_fds which differentiates between the
fds coming from preserve_fds and the ones coming from LISTEN_FDS if
LISTEN_FDS is configured set primary process to 1.

Signed-off-by: flouthoc <flouthoc.git@gmail.com>

src/create.c

@@ -120,6 +120,7 @@ crun_command_create (struct crun_global_arguments *global_args, int argc, char *
   cleanup_free char *config_file_cleanup = NULL;
 
   crun_context.preserve_fds = 0;
+  crun_context.listen_fds = 0;
   /* Check if global handler is configured and pass it down to crun context */
   crun_context.handler = global_args->handler;
 
@@ -167,7 +168,10 @@ crun_command_create (struct crun_global_arguments *global_args, int argc, char *
 
   crun_context.bundle = bundle;
   if (getenv ("LISTEN_FDS"))
-    crun_context.preserve_fds += strtoll (getenv ("LISTEN_FDS"), NULL, 10);
+    {
+      crun_context.preserve_fds += strtoll (getenv ("LISTEN_FDS"), NULL, 10);
+      crun_context.listen_fds = strtoll (getenv ("LISTEN_FDS"), NULL, 10);
+    }
 
   return libcrun_container_create (&crun_context, container, 0, err);
 }

src/exec.c

@@ -229,6 +229,7 @@ crun_command_exec (struct crun_global_arguments *global_args, int argc, char **a
   };
 
   crun_context.preserve_fds = 0;
+  crun_context.listen_fds = 0;
 
   argp_parse (&run_argp, argc, argv, ARGP_IN_ORDER, &first_arg, &exec_options);
   crun_assert_n_args (argc - first_arg, exec_options.process ? 1 : 2, -1);
@@ -243,7 +244,10 @@ crun_command_exec (struct crun_global_arguments *global_args, int argc, char **a
   crun_context.preserve_fds = exec_options.preserve_fds;
 
   if (getenv ("LISTEN_FDS"))
-    crun_context.preserve_fds += strtoll (getenv ("LISTEN_FDS"), NULL, 10);
+    {
+      crun_context.preserve_fds += strtoll (getenv ("LISTEN_FDS"), NULL, 10);
+      crun_context.listen_fds = strtoll (getenv ("LISTEN_FDS"), NULL, 10);
+    }
 
   if (exec_options.process)
     return libcrun_container_exec_process_file (&crun_context, argv[first_arg], exec_options.process, err);

src/libcrun/container.c

@@ -1187,6 +1187,13 @@ container_init_setup (void *args, pid_t own_pid, char *notify_socket, int sync_s
   if (clearenv ())
     return crun_make_error (err, errno, "clearenv");
 
+  // set primary process to 1 explicitly if nothing is configured and LISTEN_FD is not set
+  if (entrypoint_args->context->listen_fds > 0)
+    {
+      setenv ("LISTEN_PID", "1", 1);
+      libcrun_warning ("setting LISTEN_PID=1 since no previous configuration was found");
+    }
+
   if (def->process)
     {
       size_t i;

src/libcrun/container.h

@@ -35,6 +35,9 @@ struct libcrun_context_s
   const char *notify_socket;
   const char *handler;
   int preserve_fds;
+  // For some use-cases we need differentiation between preserve_fds and listen_fds.
+  // Following context variable makes sure we get exact value of listen_fds irrespective of preserve_fds.
+  int listen_fds;
 
   crun_output_handler output_handler;
   void *output_handler_arg;

src/run.c

@@ -125,6 +125,7 @@ crun_command_run (struct crun_global_arguments *global_args, int argc, char **ar
   cleanup_free char *config_file_cleanup = NULL;
 
   crun_context.preserve_fds = 0;
+  crun_context.listen_fds = 0;
   /* Check if global handler is configured and pass it down to crun context */
   crun_context.handler = global_args->handler;
 
@@ -171,7 +172,10 @@ crun_command_run (struct crun_global_arguments *global_args, int argc, char **ar
 
   crun_context.bundle = bundle;
   if (getenv ("LISTEN_FDS"))
-    crun_context.preserve_fds += strtoll (getenv ("LISTEN_FDS"), NULL, 10);
+    {
+      crun_context.preserve_fds += strtoll (getenv ("LISTEN_FDS"), NULL, 10);
+      crun_context.listen_fds = strtoll (getenv ("LISTEN_FDS"), NULL, 10);
+    }
 
   return libcrun_container_run (&crun_context, container, 0, err);
 }