config: Fix ast_config_text_file_save2 writability check for missing files

A patch I did back in 2014 modified ast_config_text_file_save2 to check the
writability of the main file and include files before truncating and re-writing
them.  An unintended side-effect of this was that if a file doesn't exist,
the check fails and the write is aborted.

This patch causes ast_config_text_file_save2 to check the writability of the
parent directory of missing files instead of checking the file itself.  This
allows missing files to be created again.  A unit test was also added to
test_config to test saving of config files.

The regression was discovered when app_voicemail's passwordlocation=spooldir
feature stopped working.

ASTERISK-25917 #close
Reported-by: Jonathan Rose

Change-Id: Ic4dbe58c277a47b674679e49daed5fc6de349f80

1 files changed, 75 insertions, 0 deletions

diff --git a/tests/test_config.c b/tests/test_config.c
index 40de2652b..fd14908b6 100644
--- a/tests/test_config.c
+++ b/tests/test_config.c
@@ -34,6 +34,7 @@
 ASTERISK_FILE_VERSION(__FILE__, "$Revision$");
 
 #include <math.h> /* HUGE_VAL */
+#include <sys/stat.h>
 
 #include "asterisk/config.h"
 #include "asterisk/module.h"
@@ -49,6 +50,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$");
 #include "asterisk/format_cap.h"
 
 #define CONFIG_FILE "test_config.conf"
+#define CONFIG_INCLUDE_FILE "test_config_include.conf"
 
 /*
  * This builds the folowing config:
@@ -881,6 +883,77 @@ static int hook_cb(struct ast_config *cfg)
 	return 0;
 }
 
+AST_TEST_DEFINE(config_save)
+{
+	enum ast_test_result_state res = AST_TEST_FAIL;
+	struct ast_flags config_flags = { 0 };
+	struct ast_config *cfg;
+	char config_filename[PATH_MAX];
+	char include_filename[PATH_MAX];
+	struct stat config_stat;
+	off_t before_save;
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "config_save";
+		info->category = "/main/config/";
+		info->summary = "Test config save";
+		info->description =
+			"Test configuration save.";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	if (write_config_file()) {
+		ast_test_status_update(test, "Could not write initial config files\n");
+		return res;
+	}
+
+	snprintf(config_filename, PATH_MAX, "%s/%s", ast_config_AST_CONFIG_DIR, CONFIG_FILE);
+	snprintf(include_filename, PATH_MAX, "%s/%s", ast_config_AST_CONFIG_DIR, CONFIG_INCLUDE_FILE);
+
+	cfg = ast_config_load(CONFIG_FILE, config_flags);
+	if (!cfg) {
+		ast_test_status_update(test, "Could not load config\n");
+		goto out;
+	}
+
+	/* We need to re-save to get the generator header */
+	if (ast_config_text_file_save(CONFIG_FILE, cfg, "TEST")) {
+		ast_test_status_update(test, "Unable to write files\n");
+		goto out;
+	}
+
+	stat(config_filename, &config_stat);
+	before_save = config_stat.st_size;
+
+	if (!ast_include_new(cfg, CONFIG_FILE, CONFIG_INCLUDE_FILE, 0, NULL, 4, include_filename, PATH_MAX)) {
+		ast_test_status_update(test, "Could not create include\n");
+		goto out;
+	}
+
+	if (ast_config_text_file_save(CONFIG_FILE, cfg, "TEST")) {
+		ast_test_status_update(test, "Unable to write files\n");
+		goto out;
+	}
+
+	stat(config_filename, &config_stat);
+	if (config_stat.st_size <= before_save) {
+		ast_test_status_update(test, "Did not save config file with #include\n");
+		goto out;
+	}
+
+	res = AST_TEST_PASS;
+
+out:
+	ast_config_destroy(cfg);
+	unlink(config_filename);
+	unlink(include_filename);
+
+	return res;
+}
+
 AST_TEST_DEFINE(config_hook)
 {
 	enum ast_test_result_state res = AST_TEST_FAIL;
@@ -1734,6 +1807,7 @@ AST_TEST_DEFINE(variable_lists_match)
 
 static int unload_module(void)
 {
+	AST_TEST_UNREGISTER(config_save);
 	AST_TEST_UNREGISTER(config_basic_ops);
 	AST_TEST_UNREGISTER(config_filtered_ops);
 	AST_TEST_UNREGISTER(config_template_ops);
@@ -1748,6 +1822,7 @@ static int unload_module(void)
 
 static int load_module(void)
 {
+	AST_TEST_REGISTER(config_save);
 	AST_TEST_REGISTER(config_basic_ops);
 	AST_TEST_REGISTER(config_filtered_ops);
 	AST_TEST_REGISTER(config_template_ops);