Fix issue in winows cli (#4881)

Author: borgmanJeremy

src/windows-cli.cpp

@@ -1,56 +1,119 @@
 #include <iostream>
+#include <string>
+#include <vector>
 #include <windows.h>
 
-std::wstring joinArgs(int argc, wchar_t* argv[])
+// Quote a single argument per the CommandLineToArgvW rules so that spaces,
+// quotes, and backslashes are preserved as literal data.
+static void appendQuotedArg(std::wstring& cmdline, const std::wstring& arg)
 {
-    std::wstring result;
-    for (int i = 1; i < argc; ++i) {
-        if (i > 1) {
-            result += L" ";
+    if (!arg.empty() && arg.find_first_of(L" \t\n\v\"") == std::wstring::npos) {
+        cmdline.append(arg);
+        return;
+    }
+
+    cmdline.push_back(L'"');
+    for (auto it = arg.begin();; ++it) {
+        unsigned backslashes = 0;
+        while (it != arg.end() && *it == L'\\') {
+            ++it;
+            ++backslashes;
+        }
+
+        if (it == arg.end()) {
+            cmdline.append(backslashes * 2, L'\\');
+            break;
+        } else if (*it == L'"') {
+            cmdline.append(backslashes * 2 + 1, L'\\');
+            cmdline.push_back(*it);
+        } else {
+            cmdline.append(backslashes, L'\\');
+            cmdline.push_back(*it);
         }
-        result += argv[i];
     }
-    return result;
+    cmdline.push_back(L'"');
 }
 
-void CallFlameshot(const std::wstring args, bool wait)
+// Launch flameshot.exe (located next to this wrapper) with argv[1..],
+// forwarding each argument as literal data. flameshot.exe is passed via
+// lpApplicationName so no command interpreter is involved and shell
+// metacharacters have no effect. When wait is true, the child's stdout is
+// captured and relayed.
+void CallFlameshot(int argc, wchar_t* argv[], bool wait)
 {
-    // generate full path for flameshot executable
+    // Full path to flameshot.exe, in the same directory as this executable.
     wchar_t path[MAX_PATH];
-    int pathLength = GetModuleFileNameW(NULL, path, MAX_PATH);
+    GetModuleFileNameW(NULL, path, MAX_PATH);
     std::wstring pathstring(path);
-
-    // Find the last backslash to isolate the filename
     size_t lastBackslash = pathstring.find_last_of(L'\\');
     std::wstring directory = (lastBackslash != std::wstring::npos)
                                ? pathstring.substr(0, lastBackslash + 1)
                                : L"";
+    std::wstring exePath = directory + L"flameshot.exe";
+
+    // Build the command line with each argument individually quoted.
+    std::wstring cmdline;
+    appendQuotedArg(cmdline, exePath);
+    for (int i = 1; i < argc; ++i) {
+        cmdline.push_back(L' ');
+        appendQuotedArg(cmdline, argv[i]);
+    }
+    std::vector<wchar_t> mutableCmd(cmdline.begin(), cmdline.end());
+    mutableCmd.push_back(L'\0');
+
+    HANDLE readEnd = NULL, writeEnd = NULL;
+    STARTUPINFOW si{};
+    si.cb = sizeof(si);
 
-    // generate command string
-    // note: binary path placed within quotes in case of spaces in path
-    int cmdSize = 32 + sizeof(directory) + sizeof(args);
-    wchar_t* cmd = (wchar_t*)malloc(sizeof(wchar_t) * cmdSize);
-    swprintf(cmd,
-             cmdSize,
-             L"\"%s\\flameshot.exe\" %s",
-             directory.c_str(),
-             args.c_str());
-    // call subprocess
-    FILE* stream = _wpopen(cmd, L"r");
-    free(cmd);
     if (wait) {
-        if (stream) {
-            const int MAX_BUFFER = 2048;
-            char buffer[MAX_BUFFER];
-            while (!feof(stream)) {
-                if (fgets(buffer, MAX_BUFFER, stream) != NULL) {
-                    std::cout << buffer;
-                }
-            }
+        SECURITY_ATTRIBUTES sa{};
+        sa.nLength = sizeof(sa);
+        sa.bInheritHandle = TRUE;
+        if (!CreatePipe(&readEnd, &writeEnd, &sa, 0)) {
+            return;
         }
-        _pclose(stream);
+        SetHandleInformation(readEnd, HANDLE_FLAG_INHERIT, 0);
+
+        si.dwFlags = STARTF_USESTDHANDLES;
+        si.hStdInput = GetStdHandle(STD_INPUT_HANDLE);
+        si.hStdOutput = writeEnd;
+        si.hStdError = writeEnd;
     }
-    return;
+
+    PROCESS_INFORMATION pi{};
+    BOOL ok = CreateProcessW(exePath.c_str(),
+                             mutableCmd.data(),
+                             NULL,
+                             NULL,
+                             wait ? TRUE : FALSE,
+                             0,
+                             NULL,
+                             NULL,
+                             &si,
+                             &pi);
+
+    if (writeEnd) {
+        CloseHandle(writeEnd);
+    }
+    if (!ok) {
+        if (readEnd) {
+            CloseHandle(readEnd);
+        }
+        return;
+    }
+
+    if (wait) {
+        char buffer[2048];
+        DWORD n = 0;
+        while (ReadFile(readEnd, buffer, sizeof(buffer), &n, NULL) && n > 0) {
+            std::cout.write(buffer, n);
+        }
+        CloseHandle(readEnd);
+        WaitForSingleObject(pi.hProcess, INFINITE);
+    }
+
+    CloseHandle(pi.hProcess);
+    CloseHandle(pi.hThread);
 }
 
 // Console 'wrapper' for flameshot on windows
@@ -59,10 +122,9 @@ int wmain(int argc, wchar_t* argv[])
     // if no args, do not wait for stdout
     if (argc == 1) {
         std::cout << "Starting flameshot in daemon mode" << std::endl;
-        CallFlameshot(L"", false);
+        CallFlameshot(argc, argv, false);
     } else {
-        std::wstring argString = joinArgs(argc, argv);
-        CallFlameshot(argString, true);
+        CallFlameshot(argc, argv, true);
     }
     std::cout.flush();
     return 0;