Bug#349749: main-menu: Add pre and post scripts execution for a menu item

[Frans Pop <aragorn@tiscali.nl>]

Package: main-menu
Severity: wishlist
Tags: patch

This is a patch by Silvain Ferriol that was committed in SVN but was not 
liked by everybody and therefore needs further discussion.
Comments about it are welcome.

The changelog entry for the patch was:
* Add pre and post scripts execution for a menu item. It is useful
  if you want to interact in the installation process without creating
  a specific udeb package for that.

Index: debian/rules
===================================================================
--- debian/rules	(revision 32804)
+++ debian/rules	(revision 32805)
@@ -18,6 +18,7 @@
 	dh_testroot
 	dh_clean -k
 	dh_install main-menu usr/bin
+	dh_installdirs lib/main-menu.d lib/main-menu-pre.d lib/main-menu-post.d
 
 binary-indep: build install
 
Index: main-menu.c
===================================================================
--- main-menu.c	(revision 32804)
+++ main-menu.c	(revision 32805)
@@ -507,34 +507,32 @@
 	debconf_capb(debconf, "backup");
 }
 
-/* Cheap-and-cheerful run-parts-a-like for /lib/main-menu.d. Allows packages
- * to register scripts to be run at main-menu startup that need to share
- * main-menu's debconf frontend but that don't merit a menu item, such as
- * setting an info message.
- */
-static void menu_startup (void) {
+/* execute scripts in a directory */
+static void do_scripts (const char *dir) {
 	struct dirent **namelist;
 	int entries, i;
 
 	/* scandir() isn't POSIX, but it makes things easy. */
-	entries = scandir(MAIN_MENU_DIR, &namelist, NULL, alphasort);
+	entries = scandir(dir, &namelist, NULL, alphasort);
 	if (entries < 0)
 		return;
 
 	for (i = 0; i < entries; ++i) {
+		int ret;
+		
 		size_t len;
 		char *filename;
 		struct stat st;
-		int ret;
-
+		
 		if (strcmp(namelist[i]->d_name, ".") == 0 || strcmp(namelist[i]->d_name, "..") == 0)
 			continue;
-
+		
 		/* sizeof(MAIN_MENU_DIR) includes trailing \0 */
-		len = sizeof(MAIN_MENU_DIR) + 1 + strlen(namelist[i]->d_name);
+		len = strlen(dir) + 1 + strlen(namelist[i]->d_name) + 1;
 		filename = di_new(char, len);
-		snprintf(filename, len, "%s/%s", MAIN_MENU_DIR, namelist[i]->d_name);
-
+		
+		snprintf(filename, len, "%s/%s", dir, namelist[i]->d_name);
+		di_log(DI_LOG_LEVEL_INFO, "filename=%s", filename);
 		if (stat(filename, &st) != 0) {
 			di_log(DI_LOG_LEVEL_WARNING, "Can't stat %s (%s)", filename, strerror(errno));
 			di_free(filename);
@@ -550,16 +548,48 @@
 			di_free(filename);
 			continue;
 		}
-
+		
 		di_log(DI_LOG_LEVEL_DEBUG, "Executing %s", filename);
 		ret = system(filename);
 		if (ret != 0)
 			di_log(DI_LOG_LEVEL_WARNING, "%s exited with status %d", filename, ret);
-
+		
 		di_free(filename);
 	}
 }
 
+/* Cheap-and-cheerful run-parts-a-like for /lib/main-menu.d. Allows packages
+ * to register scripts to be run at main-menu startup that need to share
+ * main-menu's debconf frontend but that don't merit a menu item, such as
+ * setting an info message.
+ */
+static void menu_startup (void) {
+	do_scripts(MAIN_MENU_DIR);
+}
+
+static void package_scripts(char *pkg_name, char *dir) {
+	size_t len;
+	char *pkg_dir_name;
+
+	len = strlen(dir) + 1 + strlen(pkg_name) + 1;
+	pkg_dir_name = di_new(char, len);
+	
+	snprintf(pkg_dir_name, len, "%s/%s", dir, pkg_name);
+	di_log(DI_LOG_LEVEL_INFO, "pkg_dir_name=%s", pkg_dir_name);
+
+	do_scripts(pkg_dir_name);
+	di_free(pkg_dir_name);
+}
+
+static void package_pre(char *pkg_name) {
+	di_log(DI_LOG_LEVEL_INFO, "Start Pre-scripts for package %s", pkg_name);
+	package_scripts(pkg_name, MAIN_MENU_PRE_DIR);
+}
+static void package_post(char *pkg_name) {
+	di_log(DI_LOG_LEVEL_INFO, "Start Post-scripts for package %s", pkg_name);
+	package_scripts(pkg_name, MAIN_MENU_POST_DIR);
+}
+
 int main (int argc __attribute__ ((unused)), char **argv) {
 	di_system_package *p;
 	di_packages *packages;
@@ -577,11 +607,14 @@
 	allocator = di_system_packages_allocator_alloc ();
 	packages = di_system_packages_status_read_file(DI_SYSTEM_DPKG_STATUSFILE, allocator);
 	while ((p=show_main_menu(packages, allocator))) {
+		package_pre(p->p.package);
 		ret = do_menu_item(p);
 		adjust_default_priority();
 		switch (ret) {
 			case EXIT_OK:
 				/* Success */
+				package_post(p->p.package);
+
 				if (p->installer_menu_item < NEVERDEFAULT) {
 					last_successful_item = p->installer_menu_item;
 					modify_debconf_priority(RAISE);
Index: main-menu.h
===================================================================
--- main-menu.h	(revision 32804)
+++ main-menu.h	(revision 32805)
@@ -13,6 +13,8 @@
 #define MISSING_PROVIDE "debian-installer/missing-provide"
 #define ITEM_FAILURE	"debian-installer/main-menu/item-failure"
 #define MAIN_MENU_DIR	"/lib/main-menu.d"
+#define MAIN_MENU_PRE_DIR	"/lib/main-menu-pre.d"
+#define MAIN_MENU_POST_DIR	"/lib/main-menu-post.d"
 
 #include <debian-installer.h>