From 7d639339e0c46311f8873d560e6f168e71473cd9 Mon Sep 17 00:00:00 2001
From: Ron Yorston <rmy@pobox.com>
Date: Thu, 13 Aug 2020 11:43:26 +0100
Subject: win32: use a static buffer in get_system_drive()

Allocate static storage for the system drive string instead of
making a new allocation on every call.  This is easier to manage.

Adds 16 bytes.
---
 win32/mingw.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

(limited to 'win32')

diff --git a/win32/mingw.c b/win32/mingw.c
index d9bb6e973..8501ecdd4 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -1682,16 +1682,17 @@ int root_len(const char *path)
 	return unc_root_len(path);
 }
 
-char *get_system_drive(void)
+const char *get_system_drive(void)
 {
 	struct passwd *pwd;
-	char *drive = NULL;
+	static char *drive = NULL;
 	int len;
 
-	pwd = getpwuid(0);
-	if (pwd != NULL && (len=root_len(pwd->pw_dir))) {
-		drive = xstrdup(pwd->pw_dir);
-		drive[len] = '\0';
+	if (drive == NULL) {
+		pwd = getpwuid(0);
+		if (pwd != NULL && (len=root_len(pwd->pw_dir))) {
+			drive = xstrndup(pwd->pw_dir, len);
+		}
 	}
 
 	return drive;
@@ -1699,14 +1700,11 @@ char *get_system_drive(void)
 
 int chdir_system_drive(void)
 {
-	char *sd = get_system_drive();
+	const char *sd = get_system_drive();
 	int ret = -1;
 
-	if (sd) {
-		strcat(sd, "/");
-		ret = chdir(sd);
-	}
-	free(sd);
+	if (sd)
+		ret = chdir(auto_string(concat_path_file(sd, "")));
 	return ret;
 }
 
@@ -1722,13 +1720,14 @@ int chdir_system_drive(void)
  */
 char *xabsolute_path(char *path)
 {
-	char *rpath, *sd;
+	char *rpath;
+	const char *sd;
 
 	if (root_len(path) != 0)
 		return path;	// absolute path
 	rpath = xmalloc_realpath(path);
 	if (rpath) {
-		sd = auto_string(get_system_drive());
+		sd = get_system_drive();
 		if (sd && is_prefixed_with_case(rpath, sd)) {
 			free(rpath);
 			return path;	// resolved path is on system drive
-- 
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