Ticket #12668: keyfile-envvars.patch

src/interface/fzputtygen_interface.cpp

@@ -9 +9 @@
 
 #include <wx/filedlg.h>
 
+// mbsrtowcs, mbsrtowcs_s and getenv
+#include <stdlib.h>
+#include <wchar.h>
+#include <stdexcept>
+
+// Unnamed namespace for scoping
+namesapce {
+
+    // Safe conversion from char* to string
+    inline std::string to_string(const char* str) {
+        return str ? std::string(str) : std::string("");
+    }
+
+    // Safe conversion from wchar_t* to wstring
+    inline std::wstring to_string(const wchar_t* str) {
+        return str ? std::wstring(str) : std::wstring("");
+    }
+
+    // mbsrtowcs_s should be used on MS platforms when _MSC_VER >= 1400.
+    inline std::wstring mbstring_to_wstring(const std::string& str) {
+        const char* cs = str.c_str();
+        size_t size = 0;
+
+#if _MSC_VER >= 1400
+        size_t len = str.length()+1;
+        errno_t err;
+        err = mbsrtowcs_s(&size, NULL, 0, cs, len);
+
+        if (err != 0) {
+            throw std::runtime_error("mbsrtowcs_s failed");
+        }
+
+        std::vector<wchar_t> buf(size);
+        err = mbsrtowcs_s(&size, &buf[0], buf.size(), cs, len);
+
+        if (err != 0) {
+            throw std::runtime_error("mbsrtowcs_s failed");
+        }
+#else
+        size = mbsrtowcs(NULL, &cs, 0, NULL);
+
+        if (size == size_t(-1)) {
+            throw std::runtime_error("mbsrtowcs failed");
+        }
+
+        std::vector<wchar_t> buf(size + 1);
+        size = mbsrtowcs(&buf[0], &cs, buf.size(), NULL);
+
+        if (size == size_t(-1)) {
+            throw std::runtime_error("mbsrtowcs failed");
+        }
+#endif
+
+        // Trim trailing NULL character, if present
+        std::wstring res(&buf[0], buf.size());
+        if (! res.empty() && *(res.end()-1) == '\0')
+            res.erase(res.end()-1);
+        
+        return res;
+    }
+
+    // str is source string, t is target string, r is replacement string
+    inline void maybe_replace(std::wstring& str, const std::wtring& t, const wstring& r) {
+        std::wstring::size_type pos = 0;
+        if ((pos = str.find(t)) != std::wstring::npos) {
+            str.replace(pos, t.length(), r);
+        }
+    }
+}
+
 CFZPuttyGenInterface::CFZPuttyGenInterface(wxWindow* parent)
     : m_parent(parent)
 {
@@ -62 +132 @@
     return reply == _T("1") ? 1 : 0;
 }
 
+// Should wxExpandEnvVars be used here? Something like:
+//     std::wstring t = wxExpandEnvVars(keyFile);
+//     std::swap(t, keyFile);
+bool CFZPuttyGenInterface::ExpandEnvVars(std::wstring& keyFile)
+{
+    // See if we can early out
+    if (keyFile.find(_T("$")) == std::wstring::npos)
+        return true;
+
+    std::wstring s(keyFile);
+
+    try {
+        std::wstring t, v;
+
+        // For the next 4 replacements
+        v = std::wstring(mbstring_to_wstring(to_string(getenv("HOME"))));
+        if (! v.empty()) {
+            // Not an envar, but a Bashism
+            t = _T("~/");
+            if (s.substr(0,2) == t) {
+                s.replace(0, t.length(), v);
+            }
+
+            t = _T("${HOME}");
+            maybe_replace(s, t, v);
+
+            t = _T("$(HOME)");
+            maybe_replace(s, t, v);
+
+            t = _T("$HOME");
+            maybe_replace(s, t, v);
+        }
+    }
+    catch(std::excpetion& ) {
+        return false;
+    }
+    
+    std::swap(s, keyFile);
+    return true;
+}
+
 bool CFZPuttyGenInterface::LoadKeyFile(std::wstring& keyFile, bool silent, std::wstring& comment, std::wstring& data)
 {
     if (!LoadProcess(silent)) {
@@ -69 +180 @@
         return false;
     }
 
+    // Allow failure. A failure means keyFile is unchanged, which is the behavior of the previous code.
+    (void)ExpandEnvVars(keyFile);
+
     int needs_conversion = NeedsConversion(keyFile, silent);
     if (needs_conversion < 0) {
         comment = fztranslate("Could not load key file");

src/interface/fzputtygen_interface.h

@@ -10 +10 @@
 public:
     CFZPuttyGenInterface(wxWindow* parent);
     virtual ~CFZPuttyGenInterface();
+    // Expand some envars in a key file name, like $HOME/.ssh/id_ed25519
+    bool ExpandEnvVars(std::wstring& str);
     bool LoadKeyFile(std::wstring& keyFile, bool silent, std::wstring& comment, std::wstring& data);
 
     bool ProcessFailed() const;