applet: rework APK_DEFINE_APPLET to use constructor attribute

this allows the applet registration to work in a portable way, without having to
weird things with the linker.

ref #10794

[TT: rebased for 2.12]

4 files changed, 29 insertions, 40 deletions

diff --git a/src/apk.c b/src/apk.c
index 33d2ec1..7cb173d 100644
--- a/src/apk.c
+++ b/src/apk.c
@@ -34,9 +34,6 @@
 #include "apk_print.h"
 #include "apk_io.h"
 
-static struct list_head apk_applet_list;
-#define foreach_applet(iter) list_for_each_entry(iter, &apk_applet_list, node)
-
 #ifdef TEST_MODE
 static const char *test_installed_db = NULL;
 static const char *test_world = NULL;
@@ -282,22 +279,10 @@ const struct apk_option_group optgroup_commit = {
 static int usage(struct apk_applet *applet)
 {
 	version();
-	apk_help(applet);
+	apk_applet_help(applet);
 	return 1;
 }
 
-static struct apk_applet *find_applet(const char *name)
-{
-	struct apk_applet *a;
-
-	foreach_applet(a) {
-		if (strcmp(name, a->name) == 0)
-			return a;
-	}
-
-	return NULL;
-}
-
 static struct apk_applet *deduce_applet(int argc, char **argv)
 {
 	struct apk_applet *a;
@@ -311,11 +296,11 @@ static struct apk_applet *deduce_applet(int argc, char **argv)
 		prog++;
 
 	if (strncmp(prog, "apk_", 4) == 0)
-		return find_applet(prog + 4);
+		return apk_applet_find(prog + 4);
 
 	for (i = 1; i < argc; i++) {
 		if (argv[i][0] == '-') continue;
-		a = find_applet(argv[i]);
+		a = apk_applet_find(argv[i]);
 		if (a) return a;
 	}
 
@@ -432,22 +417,6 @@ static void setup_automatic_flags(void)
 		apk_flags |= APK_INTERACTIVE;
 }
 
-void apk_applet_register(struct apk_applet *applet)
-{
-	list_init(&applet->node);
-	list_add_tail(&applet->node, &apk_applet_list);
-}
-
-static void apk_applet_register_builtin(void)
-{
-	extern apk_init_func_t __start_initapplets[], __stop_initapplets[];
-	apk_init_func_t *p;
-
-	list_init(&apk_applet_list);
-	for (p = __start_initapplets; p < __stop_initapplets; p++)
-		(*p)();
-}
-
 static struct apk_database db;
 
 static void on_sigint(int s)
@@ -468,7 +437,6 @@ int main(int argc, char **argv)
 #ifdef TEST_MODE
 	apk_string_array_init(&test_repos);
 #endif
-	apk_applet_register_builtin();
 
 	apk_argv = malloc(sizeof(char*[argc+2]));
 	memcpy(apk_argv, argv, sizeof(char*[argc]));
diff --git a/src/apk_applet.h b/src/apk_applet.h
index 3bc2eb9..0ae33b4 100644
--- a/src/apk_applet.h
+++ b/src/apk_applet.h
@@ -63,12 +63,11 @@ struct apk_applet {
 
 extern const struct apk_option_group optgroup_global, optgroup_commit;
 
-void apk_help(struct apk_applet *applet);
 void apk_applet_register(struct apk_applet *);
-typedef void (*apk_init_func_t)(void);
+struct apk_applet *apk_applet_find(const char *name);
+void apk_applet_help(struct apk_applet *applet);
 
 #define APK_DEFINE_APPLET(x) \
-static void __register_##x(void) { apk_applet_register(&x); } \
-static apk_init_func_t __regfunc_##x __attribute__((__section__("initapplets"))) __attribute((used)) = __register_##x;
+__attribute__((constructor)) static void __register_##x(void) { apk_applet_register(&x); }
 
 #endif
diff --git a/src/apk_defines.h b/src/apk_defines.h
index 6e54076..dbb21bf 100644
--- a/src/apk_defines.h
+++ b/src/apk_defines.h
@@ -212,6 +212,7 @@ APK_ARRAY(apk_string_array, char *);
 #define foreach_array_item(iter, array) \
 	for (iter = &(array)->item[0]; iter < &(array)->item[(array)->num]; iter++)
 
+#define LIST_HEAD(name) struct list_head name = { &name, &name }
 #define LIST_END (void *) 0xe01
 #define LIST_POISON1 (void *) 0xdeadbeef
 #define LIST_POISON2 (void *) 0xabbaabba
diff --git a/src/help.c b/src/help.c
index 3034da2..c8bba70 100644
--- a/src/help.c
+++ b/src/help.c
@@ -10,6 +10,27 @@
 #include "apk_applet.h"
 #include "apk_print.h"
 
+static LIST_HEAD(apk_applet_list);
+
+#define apk_applet_foreach(iter) list_for_each_entry(iter, &apk_applet_list, node)
+
+void apk_applet_register(struct apk_applet *applet)
+{
+	list_init(&applet->node);
+	list_add_tail(&applet->node, &apk_applet_list);
+}
+
+struct apk_applet *apk_applet_find(const char *name)
+{
+	struct apk_applet *a;
+
+	apk_applet_foreach(a) {
+		if (strcmp(name, a->name) == 0)
+			return a;
+	}
+	return NULL;
+}
+
 static inline int is_group(struct apk_applet *applet, const char *topic)
 {
 	if (!applet) return strcasecmp(topic, "apk") == 0;
@@ -19,7 +40,7 @@ static inline int is_group(struct apk_applet *applet, const char *topic)
 	return 0;
 }
 
-void apk_help(struct apk_applet *applet)
+void apk_applet_help(struct apk_applet *applet)
 {
 #include "help.h"