From ab3dbb68ff59032ac7fc2669b9b5ac9860f8a00f Mon Sep 17 00:00:00 2001
From: Michael Skec <mike@skec.site>
Date: Fri, 1 Dec 2023 20:22:51 +1100
Subject: [PATCH 1/2] XDG base directory: read fdm.conf from XDG_CONFIG_HOME

Implements https://github.com/nicm/fdm/issues/96

https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html

If no configuration file is specified on the command-line,
$XDG_CONFIG_HOME/fdm.conf is now the first file checked, then
$HOME/.fdm.conf, and finally the system-wide /etc/fdm.conf.

This allows the user to specify where they would like the configuration
file to be stored.  E.g. many users like to set XDG_CONFIG_HOME to
$HOME/.config so that all their XDG-compliant programs have their
configuration files stored there rather than in their home directory (or
other arbitrary locations).
---
 fdm.c | 21 +++++++++++++++------
 fdm.h |  8 +++++---
 2 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/fdm.c b/fdm.c
index 7b21d7d..e37450b 100644
--- a/fdm.c
+++ b/fdm.c
@@ -445,11 +445,20 @@ main(int argc, char **argv)
 
 	/* Find the config file. */
 	if (conf.conf_file == NULL) {
-		/* If no file specified, try ~ then /etc. */
-		xasprintf(&conf.conf_file, "%s/%s", conf.user_home, CONFFILE);
-		if (access(conf.conf_file, R_OK) != 0) {
-			xfree(conf.conf_file);
-			conf.conf_file = xstrdup(SYSCONFFILE);
+		/* If no file specified, try $XDG_CONFIG_HOME, then ~ then /etc. */
+		if ((s = getenv("XDG_CONFIG_HOME")) != NULL) {
+			xasprintf(&conf.conf_file, "%s/%s", s, CONFFILE);
+			if (access(conf.conf_file, R_OK) != 0) {
+				xfree(conf.conf_file);
+				conf.conf_file = NULL;
+			}
+		}
+		if (conf.conf_file == NULL) {
+			xasprintf(&conf.conf_file, "%s/%s", conf.user_home, CONFFILE_HOME);
+			if (access(conf.conf_file, R_OK) != 0) {
+				xfree(conf.conf_file);
+				conf.conf_file = xstrdup(SYSCONFFILE);
+			}
 		}
 	}
 	log_debug2("loading configuration from %s", conf.conf_file);
@@ -702,7 +711,7 @@ main(int argc, char **argv)
 		if (geteuid() == 0)
 			lock = xstrdup(SYSLOCKFILE);
 		else
-			xasprintf(&lock, "%s/%s", conf.user_home, LOCKFILE);
+			xasprintf(&lock, "%s/%s", conf.user_home, LOCKFILE_HOME);
 	}
 retry:
 	if (*lock != '\0' && !conf.allow_many) {
diff --git a/fdm.h b/fdm.h
index 0d63e34..e63ff3f 100644
--- a/fdm.h
+++ b/fdm.h
@@ -52,9 +52,11 @@
 #include <openssl/ssl.h>
 #include <openssl/err.h>
 
-#define CHILDUSER	"_fdm"
-#define CONFFILE	".fdm.conf"
-#define LOCKFILE	".fdm.lock"
+#define CHILDUSER		"_fdm"
+#define CONFFILE		"fdm.conf"
+#define LOCKFILE		"fdm.lock"
+#define CONFFILE_HOME	"." CONFFILE
+#define LOCKFILE_HOME	"." LOCKFILE
 #define DEFLOCKTIMEOUT	10
 #define MAXQUEUEVALUE	50
 #define DEFMAILQUEUE	2

From 677e19100ff95bd64c11d22401a5c639b6e9b2c0 Mon Sep 17 00:00:00 2001
From: Michael Skec <mike@skec.site>
Date: Sat, 2 Dec 2023 10:37:15 +1100
Subject: [PATCH 2/2] XDG base directory: lock file in XDG_RUNTIME_DIR

Continuation of https://github.com/nicm/fdm/issues/96 implementation.

From https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html:

> There is a single base directory relative to which user-specific
> runtime files and other file objects should be placed.  This directory
> is defined by the environment variable $XDG_RUNTIME_DIR.

This also may provide slight performance benefits to this as
XDG_RUNTIME_DIR is often set to a directory under /tmp which some
systems configure to be mounted as tmpfs.

If XDG_RUNTIME_DIR is not set or is an empty string, the old behaviour
of the user's home directory is used.
---
 fdm.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/fdm.c b/fdm.c
index e37450b..37c910a 100644
--- a/fdm.c
+++ b/fdm.c
@@ -446,7 +446,8 @@ main(int argc, char **argv)
 	/* Find the config file. */
 	if (conf.conf_file == NULL) {
 		/* If no file specified, try $XDG_CONFIG_HOME, then ~ then /etc. */
-		if ((s = getenv("XDG_CONFIG_HOME")) != NULL) {
+		s = getenv("XDG_CONFIG_HOME");
+		if (s != NULL && *s != '\0') {
 			xasprintf(&conf.conf_file, "%s/%s", s, CONFFILE);
 			if (access(conf.conf_file, R_OK) != 0) {
 				xfree(conf.conf_file);
@@ -711,7 +712,15 @@ main(int argc, char **argv)
 		if (geteuid() == 0)
 			lock = xstrdup(SYSLOCKFILE);
 		else
-			xasprintf(&lock, "%s/%s", conf.user_home, LOCKFILE_HOME);
+		{
+			/* Lockfile is stored in XDG_RUNTIME_DIR if provided.
+			 * If not, we store it in the user's home directory. */
+			s = getenv("XDG_RUNTIME_DIR");
+			if (s != NULL && *s != '\0')
+				xasprintf(&lock, "%s/%s", s, LOCKFILE);
+			else
+				xasprintf(&lock, "%s/%s", conf.user_home, LOCKFILE_HOME);
+		}
 	}
 retry:
 	if (*lock != '\0' && !conf.allow_many) {