libusbgx: Add return value to config related functions.

Each usbg_set_config_*() may fail so it should have
a return value to notify user about reason of failure.

To be consistent with rest of API usbg_create_config()
should also return error code to notify user about reasons
of failure instead of binary information (NULL or not).

Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
[Port from libusbg and update description]
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>

3 files changed, 81 insertions, 56 deletions

diff --git a/examples/gadget-acm-ecm.c b/examples/gadget-acm-ecm.c
index 678514c..cda3808 100644
--- a/examples/gadget-acm-ecm.c
+++ b/examples/gadget-acm-ecm.c
@@ -87,8 +87,8 @@ int main(void)
 		goto out2;
 	}
 
-	c = usbg_create_config(g, "c.1", NULL /* use defaults */, &c_strs);
-	if (!c) {
+	usbg_ret = usbg_create_config(g, "c.1", NULL /* use defaults */, &c_strs, &c);
+	if (usbg_ret != USBG_SUCCESS) {
 		fprintf(stderr, "Error creating config\n");
 		goto out2;
 	}
diff --git a/include/usbg/usbg.h b/include/usbg/usbg.h
index 5a84066..102e2ef 100644
--- a/include/usbg/usbg.h
+++ b/include/usbg/usbg.h
@@ -466,10 +466,12 @@ extern int usbg_get_function_name(usbg_function *f, char *buf, size_t len);
  * @param name Name of configuration
  * @param c_attrs Configuration attributes to be set
  * @param c_strs Configuration strings to be set
- * @return Pointer to configuration or NULL if it cannot be created
+ * @param c Pointer to be filled with pointer to configuration
+ * @note Given strings are assumed to be in US English
+ * @return 0 on success usbg_error if error occurred
  */
-extern usbg_config *usbg_create_config(usbg_gadget *g, char *name,
-		usbg_config_attrs *c_attrs, usbg_config_strs *c_strs);
+extern int usbg_create_config(usbg_gadget *g, char *name,
+		usbg_config_attrs *c_attrs, usbg_config_strs *c_strs, usbg_config **c);
 
 /**
  * @brief Get config name length
@@ -491,8 +493,9 @@ extern int usbg_get_config_name(usbg_config *c, char *buf, size_t len);
  * @brief Set the USB configuration attributes
  * @param c Pointer to configuration
  * @param c_attrs Configuration attributes
+ * @return 0 on success or usbg_error if error occurred.
  */
-extern void usbg_set_config_attrs(usbg_config *c,
+extern int usbg_set_config_attrs(usbg_config *c,
 		usbg_config_attrs *c_attrs);
 
 /**
@@ -508,15 +511,17 @@ extern usbg_config_attrs *usbg_get_config_attrs(usbg_config *c,
  * @brief Set the configuration maximum power
  * @param c Pointer to config
  * @param bMaxPower Maximum power (in 2 mA units)
+ * @return 0 on success or usbg_error if error occurred.
  */
-extern void usbg_set_config_max_power(usbg_config *c, int bMaxPower);
+extern int usbg_set_config_max_power(usbg_config *c, int bMaxPower);
 
 /**
  * @brief Set the configuration bitmap attributes
  * @param c Pointer to config
  * @param bmAttributes Configuration characteristics
+ * @return 0 on success or usbg_error if error occurred.
  */
-extern void usbg_set_config_bm_attrs(usbg_config *c, int bmAttributes);
+extern int usbg_set_config_bm_attrs(usbg_config *c, int bmAttributes);
 
 /**
  * @brief Get the USB configuration strings
@@ -533,8 +538,9 @@ extern usbg_config_strs *usbg_get_config_strs(usbg_config *c, int lang,
  * @param c Pointer to configuration
  * @param lang USB language ID
  * @param c_sttrs Configuration strings
+ * @return 0 on success, usbg_error on failure.
  */
-extern void usbg_set_config_strs(usbg_config *c, int lang,
+extern int usbg_set_config_strs(usbg_config *c, int lang,
 		usbg_config_strs *c_strs);
 
 /**
@@ -542,8 +548,9 @@ extern void usbg_set_config_strs(usbg_config *c, int lang,
  * @param c Pointer to config
  * @param lang USB language ID
  * @param string Configuration description
+ * @return 0 on success, usbg_error on failure.
  */
-extern void usbg_set_config_string(usbg_config *c, int lang, char *string);
+extern int usbg_set_config_string(usbg_config *c, int lang, char *string);
 
 /**
  * @brief Add a function to a configuration
diff --git a/src/usbg.c b/src/usbg.c
index 08cd397..24e5466 100644
--- a/src/usbg.c
+++ b/src/usbg.c
@@ -1216,53 +1216,58 @@ int usbg_create_function(usbg_gadget *g, usbg_function_type type,
 	return ret;
 }
 
-usbg_config *usbg_create_config(usbg_gadget *g, char *name,
-		usbg_config_attrs *c_attrs, usbg_config_strs *c_strs)
+int usbg_create_config(usbg_gadget *g, char *name,
+		usbg_config_attrs *c_attrs, usbg_config_strs *c_strs, usbg_config **c)
 {
 	char cpath[USBG_MAX_PATH_LENGTH];
-	usbg_config *c;
-	int ret;
+	usbg_config *conf;
+	int ret = USBG_ERROR_INVALID_PARAM;
 
-	if (!g)
-		return NULL;
+	if (!g || !c)
+		return ret;
 
 	/**
 	 * @todo Check for legal configuration name
 	 */
-	c = usbg_get_config(g, name);
-	if (c) {
+	conf = usbg_get_config(g, name);
+	if (conf) {
 		ERROR("duplicate configuration name\n");
-		return NULL;
+		return USBG_ERROR_EXIST;
 	}
 
 	sprintf(cpath, "%s/%s/%s/%s", g->path, g->name, CONFIGS_DIR, name);
 
-	c = malloc(sizeof(usbg_config));
-	if (!c) {
-		ERRORNO("allocating configuration\n");
-		return NULL;
-	}
+	*c = malloc(sizeof(usbg_config));
+	conf = *c;
+	if (conf) {
+		TAILQ_INIT(&conf->bindings);
+		strcpy(conf->name, name);
+		sprintf(conf->path, "%s/%s/%s", g->path, g->name, CONFIGS_DIR);
 
-	TAILQ_INIT(&c->bindings);
-	strcpy(c->name, name);
-	sprintf(c->path, "%s/%s/%s", g->path, g->name, CONFIGS_DIR);
-
-	ret = mkdir(cpath, S_IRWXU|S_IRWXG|S_IRWXO);
-	if (ret < 0) {
-		ERRORNO("%s\n", cpath);
-		free(c);
-		return NULL;
-	}
+		ret = mkdir(cpath, S_IRWXU|S_IRWXG|S_IRWXO);
+		if (!ret) {
+			ret = USBG_SUCCESS;
+			if (c_attrs)
+				ret = usbg_set_config_attrs(conf, c_attrs);
 
-	if (c_attrs)
-		usbg_set_config_attrs(c, c_attrs);
+			if (ret == USBG_SUCCESS && c_strs)
+				ret = usbg_set_config_string(conf, LANG_US_ENG,
+						c_strs->configuration);
 
-	if (c_strs)
-		usbg_set_config_string(c, LANG_US_ENG, c_strs->configuration);
+		} else {
+			ret = usbg_translate_error(errno);
+		}
 
-	INSERT_TAILQ_STRING_ORDER(&g->configs, chead, name, c, cnode);
+		if (ret == USBG_SUCCESS)
+			INSERT_TAILQ_STRING_ORDER(&g->configs, chead, name, conf, cnode);
+		else
+			usbg_free_config(conf);
+	} else {
+		ERRORNO("allocating configuration\n");
+		ret = USBG_ERROR_NO_MEM;
+	}
 
-	return c;
+	return ret;
 }
 
 size_t usbg_get_config_name_len(usbg_config *c)
@@ -1297,13 +1302,18 @@ int usbg_get_function_name(usbg_function *f, char *buf, size_t len)
 	return ret;
 }
 
-void usbg_set_config_attrs(usbg_config *c, usbg_config_attrs *c_attrs)
+int usbg_set_config_attrs(usbg_config *c, usbg_config_attrs *c_attrs)
 {
-	if (!c || !c_attrs)
-		return;
+	int ret = USBG_ERROR_INVALID_PARAM;
 
-	usbg_write_dec(c->path, c->name, "MaxPower", c_attrs->bMaxPower);
-	usbg_write_hex8(c->path, c->name, "bmAttributes", c_attrs->bmAttributes);
+	if (c && !c_attrs) {
+		ret = usbg_write_dec(c->path, c->name, "MaxPower", c_attrs->bMaxPower);
+		if (ret == USBG_SUCCESS)
+			ret = usbg_write_hex8(c->path, c->name, "bmAttributes",
+					c_attrs->bmAttributes);
+	}
+
+	return ret;
 }
 
 usbg_config_attrs *usbg_get_config_attrs(usbg_config *c,
@@ -1317,14 +1327,16 @@ usbg_config_attrs *usbg_get_config_attrs(usbg_config *c,
 	return c_attrs;
 }
 
-void usbg_set_config_max_power(usbg_config *c, int bMaxPower)
+int usbg_set_config_max_power(usbg_config *c, int bMaxPower)
 {
-	usbg_write_dec(c->path, c->name, "MaxPower", bMaxPower);
+	return c ? usbg_write_dec(c->path, c->name, "MaxPower", bMaxPower)
+			: USBG_ERROR_INVALID_PARAM;
 }
 
-void usbg_set_config_bm_attrs(usbg_config *c, int bmAttributes)
+int usbg_set_config_bm_attrs(usbg_config *c, int bmAttributes)
 {
-	usbg_write_hex8(c->path, c->name, "bmAttributes", bmAttributes);
+	return c ? usbg_write_hex8(c->path, c->name, "bmAttributes", bmAttributes)
+			: USBG_ERROR_INVALID_PARAM;
 }
 
 usbg_config_strs *usbg_get_config_strs(usbg_config *c, int lang,
@@ -1338,21 +1350,27 @@ usbg_config_strs *usbg_get_config_strs(usbg_config *c, int lang,
 	return c_strs;
 }
 
-void usbg_set_config_strs(usbg_config *c, int lang,
+int usbg_set_config_strs(usbg_config *c, int lang,
 		usbg_config_strs *c_strs)
 {
-	usbg_set_config_string(c, lang, c_strs->configuration);
+	return usbg_set_config_string(c, lang, c_strs->configuration);
 }
 
-void usbg_set_config_string(usbg_config *c, int lang, char *str)
+int usbg_set_config_string(usbg_config *c, int lang, char *str)
 {
-	char path[USBG_MAX_PATH_LENGTH];
+	int ret = USBG_ERROR_INVALID_PARAM;
 
-	sprintf(path, "%s/%s/%s/0x%x", c->path, c->name, STRINGS_DIR, lang);
+	if (c && str) {
+		char path[USBG_MAX_PATH_LENGTH];
 
-	mkdir(path, S_IRWXU|S_IRWXG|S_IRWXO);
+		sprintf(path, "%s/%s/%s/0x%x", c->path, c->name, STRINGS_DIR, lang);
 
-	usbg_write_string(path, "", "configuration", str);
+		ret = usbg_check_dir(path);
+		if (ret == USBG_SUCCESS)
+			ret = usbg_write_string(path, "", "configuration", str);
+	}
+
+	return ret;
 }
 
 int usbg_add_config_function(usbg_config *c, char *name, usbg_function *f)