1 files changed, 60 insertions, 15 deletions

diff --git a/src/pies.c b/src/pies.c
index a8529ac..2aa110f 100644
--- a/src/pies.c
+++ b/src/pies.c
@@ -2262,7 +2262,66 @@ set_state_file_names (const char *base)
   if (!qotdfile)
     qotdfile = mkfilename (statedir, base, ".qotd");
 }
+
+/* Return 1 if pies is run from docker and 0 otherwise. */
+static int
+is_docker (void)
+{
+  FILE *fp;
+  char *id = NULL;
+  int res;
+  
+  fp = fopen ("/proc/self/cgroup", "r");
+  if (!fp)
+    return 0;
+  res = fscanf (fp, "%*d:%*[^:]:/docker/%ms\n", &id) == 1;
+  fclose (fp);
+  free (id);
+  return res;
+}
+
+/*
+ * Check if `--no-init' option is present in argv/argc.  Return 1 if so,
+ * 0 otherwise.
+ */
+static int
+no_init_option (int argc, char **argv)
+{
+  int i;
+  for (i = 1; i < argc; i++)
+    {
+      if (strcmp (argv[i], "--no-init") == 0)
+	return 1;
+    }
+  return 0;
+}
 
+/*
+ * init_detect - detect if we're run as init process.
+ * 
+ * Pies runs as init process if (1) it has PID 1, (2) is not started as docker
+ * entrypoint, and (3) the `--no-init' command line option is not given.
+ *
+ * The function sets init_process to 1 if pies runs as init process and 0
+ * otherwise.
+ *
+ * No matter the result, if PID is 1 it installs an early SIGCHLD handler,
+ * to ensure that the configuration preprocessor (if such is started) will be
+ * cleaned up properly on exit.
+ */
+static void
+init_detect (int argc, char **argv)
+{
+  init_process = getpid () == 1;
+  if (init_process)
+    {
+      int s[] = { SIGCHLD };
+      setsigvhan (sigchld_early, s, 1);
+      if (no_init_option (argc, argv) || is_docker ())
+	init_process = 0;
+    }
+}
+
 size_t pies_master_argc;
 char **pies_master_argv;
 
@@ -2290,22 +2349,8 @@ main (int argc, char **argv)
 
   set_quoting_style (NULL, shell_quoting_style);
 
-  init_process = getpid () == 1;
-  if (init_process)
-    {
-      int s[] = { SIGCHLD };
-      setsigvhan (sigchld_early, s, 1);
-    }
+  init_detect (argc, argv);
   
-  for (i = 1; i < argc; i++)
-    {
-      if (strcmp (argv[i], "--no-init") == 0)
-	{
-	  init_process = 0;
-	  break;
-	}
-    }
-
   /* Set default logging */
   if (SYSVINIT_ACTIVE)
     {