core: Not the configured but granted number of possible file descriptors.

With CLI "core show settings", simply the parameter maxfiles of the file
asterisk.conf was shown. If that parameter was not set, nothing was displayed
although the environment might have set a default number itself. Or if maxfiles
were not granted (completely), still maxfiles was shown. Now, the maximum number
of possible file descriptors in the environment is shown.

ASTERISK-26097

Change-Id: I2df5c58863b5007b34b77adbe28b885dfcdf7e0b

main/asterisk.c

@@ -596,6 +596,7 @@ static char *handle_show_settings(struct ast_cli_entry *e, int cmd, struct ast_c
 	char buf[BUFSIZ];
 	struct ast_tm tm;
 	char eid_str[128];
+	struct rlimit limits;
 
 	switch (cmd) {
 	case CLI_INIT:
@@ -617,10 +618,17 @@ static char *handle_show_settings(struct ast_cli_entry *e, int cmd, struct ast_c
 		ast_cli(a->fd, "  Maximum calls:               %d (Current %d)\n", ast_option_maxcalls, ast_active_channels());
 	else
 		ast_cli(a->fd, "  Maximum calls:               Not set\n");
-	if (ast_option_maxfiles)
-		ast_cli(a->fd, "  Maximum open file handles:   %d\n", ast_option_maxfiles);
-	else
-		ast_cli(a->fd, "  Maximum open file handles:   Not set\n");
+
+	if (getrlimit(RLIMIT_NOFILE, &limits)) {
+		ast_cli(a->fd, "  Maximum open file handles:   Error because of %s\n", strerror(errno));
+	} else if (limits.rlim_cur == RLIM_INFINITY) {
+		ast_cli(a->fd, "  Maximum open file handles:   Unlimited\n");
+	} else if (limits.rlim_cur < ast_option_maxfiles) {
+		ast_cli(a->fd, "  Maximum open file handles:   %d (is) %d (requested)\n", (int) limits.rlim_cur, ast_option_maxfiles);
+	} else {
+		ast_cli(a->fd, "  Maximum open file handles:   %d\n", (int) limits.rlim_cur);
+	}
+
 	ast_cli(a->fd, "  Root console verbosity:      %d\n", option_verbose);
 	ast_cli(a->fd, "  Current console verbosity:   %d\n", ast_verb_console_get());
 	ast_cli(a->fd, "  Debug level:                 %d\n", option_debug);