codecs: Fix ABI incompatibility created by adding format_name to ast_codec

Adding format_name even to the end of ast_codec caused issued with
binary codec modules because the pointer would be garbage in asterisk
when they registered.  So, the ast_codec structure was reverted and an
internal_ast_codec structure was created just for use in codec.c.  A new
internal-only API was also added (__ast_codec_register_with_format) so
that codec_builtin could register codecs with the format_name in a
separate parameter rather than in the ast_codec structure.

ASTERISK-26144 #close
Reported-by: Alexei Gradinari

Change-Id: I6df1b08f6a6ae089db23adfe1ebc8636330265ba

3 files changed, 52 insertions, 21 deletions

diff --git a/include/asterisk/codec.h b/include/asterisk/codec.h
index fb2b7da38..28befec50 100644
--- a/include/asterisk/codec.h
+++ b/include/asterisk/codec.h
@@ -77,8 +77,6 @@ struct ast_codec {
 	unsigned int smooth;
 	/*! \brief The module that registered this codec */
 	struct ast_module *mod;
-	/*! \brief A format name for a default sane format using this codec */
-	const char *format_name;
 };
 
 /*!
diff --git a/main/codec.c b/main/codec.c
index c8644fd34..c253233bb 100644
--- a/main/codec.c
+++ b/main/codec.c
@@ -49,6 +49,32 @@ static int codec_id = 1;
 /*! \brief Registered codecs */
 static struct ao2_container *codecs;
 
+/*!
+ * \internal
+ * \brief Internal codec structure
+ *
+ * External codecs won't know about the format_name field so the public
+ * ast_codec structure has to leave it out.  This structure will be used
+ * for the internal codecs.
+ *
+ */
+struct internal_ast_codec {
+	/*! \brief Public codec structure.  Must remain first. */
+	struct ast_codec external;
+	/*! \brief A format name for a default sane format using this codec */
+	const char *format_name;
+};
+
+/*!
+ * \internal
+ * \brief Internal function for registration with format name
+ *
+ * This function is only used by codec.c and codec_builtin.c and
+ * will be removed in Asterisk 14
+ */
+int __ast_codec_register_with_format(struct ast_codec *codec, const char *format_name,
+	struct ast_module *mod);
+
 static int codec_hash(const void *obj, int flags)
 {
 	const struct ast_codec *codec;
@@ -113,7 +139,7 @@ static int codec_cmp(void *obj, void *arg, int flags)
 static char *show_codecs(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
 {
 	struct ao2_iterator i;
-	struct ast_codec *codec;
+	struct internal_ast_codec *codec;
 
 	switch (cmd) {
 	case CLI_INIT:
@@ -144,19 +170,19 @@ static char *show_codecs(struct ast_cli_entry *e, int cmd, struct ast_cli_args *
 	for (; (codec = ao2_iterator_next(&i)); ao2_ref(codec, -1)) {
 		if (a->argc == 4) {
 			if (!strcasecmp(a->argv[3], "audio")) {
-				if (codec->type != AST_MEDIA_TYPE_AUDIO) {
+				if (codec->external.type != AST_MEDIA_TYPE_AUDIO) {
 					continue;
 				}
 			} else if (!strcasecmp(a->argv[3], "video")) {
-				if (codec->type != AST_MEDIA_TYPE_VIDEO) {
+				if (codec->external.type != AST_MEDIA_TYPE_VIDEO) {
 					continue;
 				}
 			} else if (!strcasecmp(a->argv[3], "image")) {
-				if (codec->type != AST_MEDIA_TYPE_IMAGE) {
+				if (codec->external.type != AST_MEDIA_TYPE_IMAGE) {
 					continue;
 				}
 			} else if (!strcasecmp(a->argv[3], "text")) {
-				if (codec->type != AST_MEDIA_TYPE_TEXT) {
+				if (codec->external.type != AST_MEDIA_TYPE_TEXT) {
 					continue;
 				}
 			} else {
@@ -165,11 +191,11 @@ static char *show_codecs(struct ast_cli_entry *e, int cmd, struct ast_cli_args *
 		}
 
 		ast_cli(a->fd, "%8u %-5s %-12s %-16s (%s)\n",
-			codec->id,
-			ast_codec_media_type2str(codec->type),
-			codec->name,
+			codec->external.id,
+			ast_codec_media_type2str(codec->external.type),
+			codec->external.name,
 			S_OR(codec->format_name, "no cached format"),
-			codec->description);
+			codec->external.description);
 	}
 
 	ao2_iterator_destroy(&i);
@@ -190,7 +216,7 @@ static int codec_id_cmp(void *obj, void *arg, int flags)
 static char *show_codec(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
 {
 	int type_punned_codec;
-	struct ast_codec *codec;
+	struct internal_ast_codec *codec;
 
 	switch (cmd) {
 	case CLI_INIT:
@@ -217,7 +243,7 @@ static char *show_codec(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a
 		return CLI_SUCCESS;
 	}
 
-	ast_cli(a->fd, "%11u %s (%s)\n", (unsigned int) codec->id, codec->description,
+	ast_cli(a->fd, "%11u %s (%s)\n", (unsigned int) codec->external.id, codec->external.description,
 		S_OR(codec->format_name, "no format"));
 
 	ao2_ref(codec, -1);
@@ -263,8 +289,13 @@ static void codec_dtor(void *obj)
 
 int __ast_codec_register(struct ast_codec *codec, struct ast_module *mod)
 {
+	return __ast_codec_register_with_format(codec, NULL, mod);
+}
+
+int __ast_codec_register_with_format(struct ast_codec *codec, const char *format_name, struct ast_module *mod)
+{
 	SCOPED_AO2WRLOCK(lock, codecs);
-	struct ast_codec *codec_new;
+	struct internal_ast_codec *codec_new;
 
 	/* Some types have specific requirements */
 	if (codec->type == AST_MEDIA_TYPE_UNKNOWN) {
@@ -293,8 +324,9 @@ int __ast_codec_register(struct ast_codec *codec, struct ast_module *mod)
 			codec->name, ast_codec_media_type2str(codec->type), codec->sample_rate);
 		return -1;
 	}
-	*codec_new = *codec;
-	codec_new->id = codec_id++;
+	codec_new->external = *codec;
+	codec_new->format_name = format_name;
+	codec_new->external.id = codec_id++;
 
 	ao2_link_flags(codecs, codec_new, OBJ_NOLOCK);
 
@@ -302,7 +334,7 @@ int __ast_codec_register(struct ast_codec *codec, struct ast_module *mod)
 	ast_module_shutdown_ref(mod);
 
 	ast_verb(2, "Registered '%s' codec '%s' at sample rate '%u' with id '%u'\n",
-		ast_codec_media_type2str(codec->type), codec->name, codec->sample_rate, codec_new->id);
+		ast_codec_media_type2str(codec->type), codec->name, codec->sample_rate, codec_new->external.id);
 
 	ao2_ref(codec_new, -1);
 
diff --git a/main/codec_builtin.c b/main/codec_builtin.c
index d7d253ab8..d3f65174c 100644
--- a/main/codec_builtin.c
+++ b/main/codec_builtin.c
@@ -38,6 +38,9 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/format_cache.h"
 #include "asterisk/frame.h"
 
+int __ast_codec_register_with_format(struct ast_codec *codec, const char *format_name,
+	struct ast_module *mod);
+
 enum frame_type {
 	TYPE_HIGH,     /* 0x0 */
 	TYPE_LOW,      /* 0x1 */
@@ -774,8 +777,7 @@ static struct ast_codec t140 = {
 		int __res_ ## __LINE__ = 0; \
 		struct ast_format *__fmt_ ## __LINE__; \
 		struct ast_codec *__codec_ ## __LINE__; \
-		codec.format_name = (codec).name; \
-		res |= __ast_codec_register(&(codec), NULL); \
+		res |= __ast_codec_register_with_format(&(codec), (codec).name, NULL); \
 		__codec_ ## __LINE__ = ast_codec_get((codec).name, (codec).type, (codec).sample_rate); \
 		__fmt_ ## __LINE__ = __codec_ ## __LINE__ ? ast_format_create(__codec_ ## __LINE__) : NULL; \
 		res |= ast_format_cache_set(__fmt_ ## __LINE__); \
@@ -789,8 +791,7 @@ static struct ast_codec t140 = {
 		int __res_ ## __LINE__ = 0; \
 		struct ast_format *__fmt_ ## __LINE__; \
 		struct ast_codec *__codec_ ## __LINE__; \
-		codec.format_name = fmt_name; \
-		res |= __ast_codec_register(&(codec), NULL); \
+		res |= __ast_codec_register_with_format(&(codec), fmt_name, NULL); \
 		__codec_ ## __LINE__ = ast_codec_get((codec).name, (codec).type, (codec).sample_rate); \
 		__fmt_ ## __LINE__ = ast_format_create_named((fmt_name), __codec_ ## __LINE__); \
 		res |= ast_format_cache_set(__fmt_ ## __LINE__); \