From 066451a8ad9c293dd0c454a38cbed253cdd78625 Mon Sep 17 00:00:00 2001
From: "mingang.he" <dustgle@gmail.com>
Date: Fri, 3 Mar 2023 15:09:44 +0000
Subject: [PATCH] Add /graftcp/graftcp.conf for graftcp default config

---
 README.md       |  3 ++-
 README.zh-CN.md |  3 ++-
 conf.c          | 44 ++++++++++++++++++++++++++++++++++++++++++++
 graftcp.c       |  7 +++++--
 4 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index e521cb7..e1f8e08 100644
--- a/README.md
+++ b/README.md
@@ -78,7 +78,8 @@ Usage: graftcp [options] prog [prog-args]
 
 Options:
   -c --conf-file=<config-file-path>
-                    Specify configuration file
+                    Specify configuration file.
+                    Default: $XDG_CONFIG_HOME/graftcp/graftcp.conf
   -a --local-addr=<graftcp-local-IP-addr>
                     graftcp-local's IP address. Default: localhost
   -p --local-port=<graftcp-local-port>
diff --git a/README.zh-CN.md b/README.zh-CN.md
index e5df399..5f778cc 100644
--- a/README.zh-CN.md
+++ b/README.zh-CN.md
@@ -72,7 +72,8 @@ Usage: graftcp [options] prog [prog-args]
 
 Options:
   -c --conf-file=<config-file-path>
-                    Specify configuration file
+                    Specify configuration file.
+                    Default: $XDG_CONFIG_HOME/graftcp/graftcp.conf
   -a --local-addr=<graftcp-local-IP-addr>
                     graftcp-local's IP address. Default: localhost
   -p --local-port=<graftcp-local-port>
diff --git a/conf.c b/conf.c
index 0fccdf8..5d538f9 100644
--- a/conf.c
+++ b/conf.c
@@ -16,6 +16,7 @@
 #include <string.h>
 #include <ctype.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "conf.h"
 
@@ -197,13 +198,56 @@ void conf_free(struct graftcp_conf *conf)
 	}
 }
 
+static char *xdg_config_path_dup(void)
+{
+	const char *home, *config_home;
+	char *path = NULL;
+	const char *dotconf = ".config";
+	const char *subdir = "graftcp";
+	const char *confname = "graftcp.conf";
+
+	config_home = getenv("XDG_CONFIG_HOME");
+	if (config_home && *config_home) {
+		size_t size = 3 + strlen(config_home) + strlen(subdir) + strlen(confname);
+		path = calloc(size, sizeof(char));
+		snprintf(path, size, "%s/%s/%s", config_home, subdir, confname);
+		return path;
+	}
+
+	home = getenv("HOME");
+	if (home) {
+		size_t size = 4 + strlen(home) + strlen(dotconf) + strlen(subdir) + strlen(confname);
+		path = calloc(size, sizeof(char));
+		snprintf(path, size, "%s/%s/%s/%s", home, dotconf, subdir, confname);
+		return path;
+	}
+
+	return NULL;
+}
+
 int conf_read(const char *path, struct graftcp_conf *conf)
 {
 	FILE *f;
+	__defer_free char *xdg_config = NULL;
 	__defer_free char *line = NULL;
 	size_t len = 0;
 	int err = 0;
 
+	if (path == NULL) {
+		xdg_config = xdg_config_path_dup();
+		if (xdg_config == NULL)
+			return 0;
+
+		struct stat st;
+		if (stat(xdg_config, &st))
+			return 0;
+		if (S_ISDIR(st.st_mode)) {
+			fprintf(stderr, "%s is a directory not a config file\n", xdg_config);
+			return -1;
+		}
+		path = xdg_config;
+	}
+
 	f = fopen(path, "r");
 	if (!f) {
 		fprintf(stderr, "Failed to open %s\n", path);
diff --git a/graftcp.c b/graftcp.c
index 22def87..86b1a57 100644
--- a/graftcp.c
+++ b/graftcp.c
@@ -367,7 +367,8 @@ static void usage(char **argv)
 	fprintf(stderr, "Usage: %s [options] prog [prog-args]\n\n"
 		"Options:\n"
 		"  -c --conf-file=<config-file-path>\n"
-		"                    Specify configuration file\n"
+		"                    Specify configuration file.\n"
+		"                    Default: $XDG_CONFIG_HOME/graftcp/graftcp.conf\n"
 		"  -a --local-addr=<graftcp-local-IP-addr>\n"
 		"                    graftcp-local's IP address. Default: localhost\n"
 		"  -p --local-port=<graftcp-local-port>\n"
@@ -415,6 +416,7 @@ int client_main(int argc, char **argv)
 		.ignore_local           = &DEFAULT_IGNORE_LOCAL,
 	};
 
+	__defer_free char *conf_file_path = NULL;
 	__defer_conf_free struct graftcp_conf file_conf;
 	__defer_conf_free struct graftcp_conf cmd_conf;
 	conf_init(&file_conf);
@@ -444,7 +446,7 @@ int client_main(int argc, char **argv)
 			*cmd_conf.ignore_local = false;
 			break;
 		case 'c':
-			conf_read(optarg, &file_conf);
+			conf_file_path = strdup(optarg);
 			break;
 		case 'V':
 			fprintf(stderr, "graftcp %s\n", VERSION);
@@ -456,6 +458,7 @@ int client_main(int argc, char **argv)
 			exit(0);
 		}
 	}
+	conf_read(conf_file_path, &file_conf);
 	conf_override(&conf, &file_conf);
 	conf_override(&conf, &cmd_conf);