1 files changed, 176 insertions, 0 deletions
diff --git a/shared/utils.c b/shared/utils.c
index 99fcaa3..f41a8a1 100644
--- a/shared/utils.c
+++ b/shared/utils.c
@@ -5,6 +5,7 @@
 #include <limits.h>
 #include <arpa/inet.h>
 #include <string.h>
+#include <sys/stat.h>
 #include <sys/types.h>
 #include <dirent.h>
 #include <fcntl.h>
@@ -14,11 +15,156 @@
 #include <netinet/tcp.h>
 #include <inttypes.h>
 #include <stdarg.h>
+#include <pwd.h>
 
 #include "utils.h"
 
 unsigned debug_mask = 0;
 
+static const char *get_homedir()
+{
+	const char *e;
+        struct passwd *passwd;
+        uid_t uid;
+
+	e = getenv("HOME");
+	if (e && e[0] == '/')
+		return e;
+
+	uid = getuid();
+	if (uid == 0)
+		return "/root";
+
+        passwd = getpwuid(uid);
+	if (passwd && passwd->pw_dir[0] == '/')
+		return passwd->pw_dir;
+
+	return NULL;
+}
+
+int open_subdir(int dfd, const char *subdir, bool nofail)
+{
+	int sfd;
+
+	if (nofail && mkdirat(dfd, subdir, 0777) < 0 && errno != EEXIST) {
+		error("Unable to create subdirectory %s: %m", subdir);
+		return -1;
+	}
+
+	sfd = openat(dfd, subdir, O_PATH | O_CLOEXEC | O_DIRECTORY);
+	if (sfd < 0 && nofail)
+		error("Unable to open subdirectory %s: %m", subdir);
+
+	return sfd;
+}
+
+int open_xdg_dir(const char *envname, const char *altpath, bool nofail,
+		 char **rpath)
+{
+        const char *e;
+	const char *h;
+	int dfd, hfd;
+
+	e = getenv(envname);
+	if (e && e[0] == '/') {
+		dfd = open(e, O_PATH | O_CLOEXEC | O_DIRECTORY);
+		if (dfd < 0)
+			error("Unable to open $%s(%s): %m", envname, e);
+		else if (rpath) {
+			*rpath = xstrdup(e);
+			if (!rpath) {
+				error("xstrdup: %m");
+				close(dfd);
+				return -1;
+			}
+		}
+		return dfd;
+	}
+
+	h = get_homedir();
+	if (!h) {
+		error("Unable to determine home directory");
+		return -1;
+	}
+
+	hfd = open(h, O_PATH | O_CLOEXEC | O_DIRECTORY);
+	if (hfd < 0) {
+		error("Unable to open $HOME(%s): %m", h);
+		return -1;
+	}
+
+	dfd = open_subdir(hfd, altpath, nofail);
+	close(hfd);
+
+	if (dfd >= 0 && rpath) {
+		*rpath = xstrcat(h, "/", altpath, NULL);
+		if (!*rpath) {
+			error("xstrcat: %m");
+			close(dfd);
+			return -1;
+		}
+	}
+	return dfd;
+}
+
+DIR *__open_dir(const char *user_override,
+		int (*base_dir)(bool nofail, char **rpath),
+		const char *fallback, char **rpath)
+{
+	_cleanup_close_ int xfd = -1;
+	_cleanup_close_ int mfd = -1;
+	_cleanup_free_ char *tmp = NULL;
+	DIR *dir;
+
+	/* First, use explicitly set path... */
+	if (user_override) {
+		dir = opendir(user_override);
+		if (dir && rpath) {
+			*rpath = xstrdup(user_override);
+			if (!*rpath) {
+				closedir(dir);
+				return NULL;
+			}
+		}
+		return dir;
+	}
+
+	/* ...second, attempt per-user config dir... */
+	xfd = base_dir(false, &tmp);
+	if (xfd < 0)
+		goto fallback;
+
+	mfd = openat(xfd, "minecproxy", O_CLOEXEC | O_DIRECTORY | O_RDONLY);
+	if (mfd < 0)
+		goto fallback;
+
+	dir = fdopendir(mfd);
+	if (dir)
+		mfd = -1;
+
+	if (rpath) {
+		*rpath = xstrcat(tmp, "/minecproxy", NULL);
+		if (!*rpath) {
+			closedir(dir);
+			return NULL;
+		}
+	}
+
+	return dir;
+
+	/* ...third, fallback on the system dir */
+fallback:
+	dir = opendir(fallback);
+	if (dir && rpath) {
+		*rpath = xstrdup(fallback);
+		if (!*rpath) {
+			closedir(dir);
+			return NULL;
+		}
+	}
+	return dir;
+}
+
 const char *ansi_red = "";
 const char *ansi_green = "";
 const char *ansi_yellow = "";
@@ -252,3 +398,33 @@ char *xsprintf(size_t *rlen, const char *fmt, ...)
 
 	return str;
 }
+
+char *xstrcat(const char *a, ...) {
+	size_t len;
+	const char *b;
+	char *str;
+	char *to;
+	va_list ap;
+
+	if (!a)
+		return NULL;
+
+	len = strlen(a) + 1;
+
+	va_start(ap, a);
+	while ((b = va_arg(ap, const char *)))
+		len += strlen(b);
+	va_end(ap);
+
+	str = zmalloc(len);
+	if (!str)
+		return NULL;
+	
+	to = stpcpy(str, a);
+	va_start(ap, a);
+	while ((b = va_arg(ap, const char *)))
+		to = stpcpy(to, b);
+	va_end(ap);
+
+	return str;
+}