Move get system directory to a separate function

Only refactoring to reduce code-duplication, no functional changes. Signed-off-by: Selva Nair <[email protected]> Acked-by: Gert Doering <[email protected]> Message-Id: <[email protected]> URL: https://www.mail-archive.com/[email protected]/msg17518.html Signed-off-by: Gert Doering <[email protected]>
JamessenLiu · Oct 5, 2018 · 4eb4655 · 4eb4655
1 parent 720c880
commit 4eb4655
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Showing 3 changed files with 24 additions and 18 deletions.
diff --git a/src/openvpnserv/common.c b/src/openvpnserv/common.c
@@ -25,7 +25,7 @@
 #include "validate.h"
 
 LPCTSTR service_instance = TEXT("");
-
+static wchar_t win_sys_path[MAX_PATH];
 
 /*
  * These are necessary due to certain buggy implementations of (v)snprintf,
@@ -285,3 +285,17 @@ utf8to16(const char *utf8)
     MultiByteToWideChar(CP_UTF8, 0, utf8, -1, utf16, n);
     return utf16;
 }
+
+const wchar_t *
+get_win_sys_path(void)
+{
+    const wchar_t *default_sys_path = L"C:\\Windows\\system32";
+
+    if (!GetSystemDirectoryW(win_sys_path, _countof(win_sys_path)))
+    {
+        wcsncpy(win_sys_path, default_sys_path, _countof(win_sys_path));
+        win_sys_path[_countof(win_sys_path) - 1] = L'\0';
+    }
+
+    return win_sys_path;
+}
diff --git a/src/openvpnserv/interactive.c b/src/openvpnserv/interactive.c
@@ -933,11 +933,10 @@ RegisterDNS(LPVOID unused)
 {
     DWORD err;
     DWORD i;
-    WCHAR sys_path[MAX_PATH];
     DWORD timeout = RDNS_TIMEOUT * 1000; /* in milliseconds */
 
-    /* default path of ipconfig command */
-    WCHAR ipcfg[MAX_PATH] = L"C:\\Windows\\system32\\ipconfig.exe";
+    /* path of ipconfig command */
+    WCHAR ipcfg[MAX_PATH];
 
     struct
     {
@@ -952,11 +951,8 @@ RegisterDNS(LPVOID unused)
 
     HANDLE wait_handles[2] = {rdns_semaphore, exit_event};
 
-    if (GetSystemDirectory(sys_path, MAX_PATH))
-    {
-        swprintf(ipcfg, MAX_PATH, L"%s\\%s", sys_path, L"ipconfig.exe");
-        ipcfg[MAX_PATH-1] = L'\0';
-    }
+    swprintf(ipcfg, _countof(ipcfg), L"%s\\%s", get_win_sys_path(), L"ipconfig.exe");
+    ipcfg[_countof(ipcfg) - 1] = L'\0';
 
     if (WaitForMultipleObjects(2, wait_handles, FALSE, timeout) == WAIT_OBJECT_0)
     {
@@ -1034,15 +1030,8 @@ netsh_dns_cmd(const wchar_t *action, const wchar_t *proto, const wchar_t *if_nam
     }
 
     /* Path of netsh */
-    int n = GetSystemDirectory(argv0, MAX_PATH);
-    if (n > 0 && n < MAX_PATH) /* got system directory */
-    {
-        wcsncat(argv0, L"\\netsh.exe", MAX_PATH - n - 1);
-    }
-    else
-    {
-        wcsncpy(argv0, L"C:\\Windows\\system32\\netsh.exe", MAX_PATH);
-    }
+    swprintf(argv0, _countof(argv0), L"%s\\%s", get_win_sys_path(), L"netsh.exe");
+    argv0[_countof(argv0) - 1] = L'\0';
 
     /* cmd template:
      * netsh interface $proto $action dns $if_name $addr [validate=no]

diff --git a/src/openvpnserv/service.h b/src/openvpnserv/service.h
@@ -97,4 +97,7 @@ DWORD MsgToEventLog(DWORD flags, LPCTSTR lpszMsg, ...);
 /* Convert a utf8 string to utf16. Caller should free the result */
 wchar_t *utf8to16(const char *utf8);
 
+/* return windows system directory as a pointer to a static string */
+const wchar_t *get_win_sys_path(void);
+
 #endif /* ifndef _SERVICE_H */