From 32a253d06ac407eb076c6c905eb06be5ea947f05 Mon Sep 17 00:00:00 2001
From: Frank Benkstein <frank-vlock@benkstein.net>
Date: Wed, 28 Nov 2007 00:38:03 +0100
Subject: [PATCH] src/script.c: do not launch script in init_script function

Previously scripts were always started regardless of their dependencies.  If
the dependencies were not met the script was terminated later without any hooks
run.  This is probably not what (the author of) a script expects.  Now scripts
are run when the first hook is called.
---
 src/script.c | 87 ++++++++++++++++++++++++++++++++----------------------------
 1 file changed, 46 insertions(+), 41 deletions(-)

diff --git a/src/script.c b/src/script.c
index af28e8e..e4219a2 100644
--- a/src/script.c
+++ b/src/script.c
@@ -60,26 +60,37 @@ struct plugin_type *script = &(struct plugin_type){
 
 struct script_context 
 {
+  /* The path to the script. */
+  char *path;
+  /* Was the script launched? */
+  bool launched;
+  /* Did the script die? */
+  bool dead;
   /* The pipe file descriptor that is connected to the script's stdin. */
   int fd;
   /* The PID of the script. */
   pid_t pid;
-  /* Did the script die? */
-  bool dead;
 };
 
 /* Get the dependency from the script. */ 
 static bool get_dependency(const char *path, const char *dependency_name,
     struct list *dependency_list);
-/* Launch the script creating a new script_context.  No error detection aborts
- * on fatal errors. */
-static struct script_context *launch_script(const char *path);
+/* Launch the script creating a new script_context. */
+static bool launch_script(struct script_context *script);
 
 bool init_script(struct plugin *p)
 {
-  char *path;
+  int errsv;
+  struct script_context *context = malloc(sizeof *context);
+
+  if (context == NULL)
+    return false;
 
-  if (asprintf(&path, "%s/%s", VLOCK_SCRIPT_DIR, p->name) < 0) {
+  context->dead = false;
+  context->launched = false;
+
+  if (asprintf(&context->path, "%s/%s", VLOCK_SCRIPT_DIR, p->name) < 0) {
+    free(context);
     errno = ENOMEM;
     return false;
   }
@@ -89,30 +100,23 @@ bool init_script(struct plugin *p)
    *
    * Also there is currently no error detection in case exec() fails later.
    */
-  if (access(path, X_OK) < 0) {
-    int errsv = errno;
-    free(path);
-    errno = errsv;
-    return false;
-  }
+  if (access(context->path, X_OK) < 0)
+    goto error;
 
   /* Get the dependency information. */
   for (size_t i = 0; i < nr_dependencies; i++)
-    if (!get_dependency(path, dependency_names[i], p->dependencies[i]))
-      return false;
+    if (!get_dependency(context->path, dependency_names[i], p->dependencies[i]))
+      goto error;
 
-  /* Launch the script. */
-  p->context = launch_script(path);
+  p->context = context;
+  return true;
 
-  if (p->context != NULL) {
-    free(path);
-    return true;
-  } else {
-    int errsv = errno;
-    free(path);
-    errno = errsv;
-    return false;
-  }
+error:
+  errsv = errno;
+  free(context->path);
+  free(context);
+  errno = errsv;
+  return false;
 }
 
 static void destroy_script(struct plugin *p)
@@ -120,6 +124,8 @@ static void destroy_script(struct plugin *p)
   struct script_context *context = p->context;
 
   if (context != NULL) {
+    free(context->path);
+
     /* Close the pipe. */
     (void) close(context->fd);
 
@@ -141,6 +147,14 @@ static bool call_script_hook(struct plugin *s, const char *hook_name)
   struct sigaction act;
   struct sigaction oldact;
 
+  if (!context->launched) {
+    /* Launch script. */
+    context->launched = launch_script(context);
+
+    if (!context->launched)
+      return false;
+  }
+
   if (context->dead)
     /* Nothing to do. */
     return false;
@@ -167,13 +181,12 @@ static bool call_script_hook(struct plugin *s, const char *hook_name)
   return !context->dead;
 }
 
-static struct script_context *launch_script(const char *path)
+static bool launch_script(struct script_context *script)
 {
   int fd_flags;
-  struct script_context *script = malloc(sizeof *script);
-  const char *argv[] = { path, "hooks", NULL };
+  const char *argv[] = { script->path, "hooks", NULL };
   struct child_process child = {
-    .path = path,
+    .path = script->path,
     .argv = argv,
     .stdin_fd = REDIRECT_PIPE,
     .stdout_fd = REDIRECT_DEV_NULL,
@@ -181,19 +194,11 @@ static struct script_context *launch_script(const char *path)
     .function = NULL,
   };
 
-  if (script == NULL)
-    return NULL;
-
-  if (!create_child(&child)) {
-    int errsv = errno;
-    free(script);
-    errno = errsv;
-    return NULL;
-  }
+  if (!create_child(&child))
+    return false;
 
   script->fd = child.stdin_fd;
   script->pid = child.pid;
-  script->dead = false;
 
   fd_flags = fcntl(script->fd, F_GETFL, &fd_flags);
 
@@ -202,7 +207,7 @@ static struct script_context *launch_script(const char *path)
     (void) fcntl(script->fd, F_SETFL, fd_flags);
   }
 
-  return script;
+  return true;
 }
 
 static char *read_dependency(const char *path, const char *dependency_name);
-- 
2.11.4.GIT