Simplify ASCII string conversion

wsl-launcher.c

@@ -82,31 +82,27 @@ HANDLE startWslServiceInteractive(WslInstance *instanceData){
 }
 
 HANDLE startWslServiceInteractiveA(LPCSTR serviceName, LPCSTR distributionName, WslInstance *instanceData){
-  LPCSTR serviceNameA = strdup(serviceName);
-  LPWSTR serviceNameW;
+  LPWSTR serviceNameW = NULL;
+  LPWSTR distributionNameW = NULL;
 
-  // calculate the buffer size for the converted string
-  int len = MultiByteToWideChar(CP_ACP, 0, serviceNameA, -1,
-                                NULL, 0);
+  int r = -1;
 
-  if (len == 0){
-    wslLogText(L_ERROR, L"Unable to get buffer length\n");
-    return NULL;
+  if (serviceName != NULL){
+    r = wslAtoW(serviceName, &serviceNameW);
+    if (r == -1)
+      return NULL;
+    else
+      instanceData->command = serviceNameW;
   }
 
-  // if all worked out, allocate space, and convert the string
-  serviceNameW = (LPWSTR)malloc(len * sizeof(wchar_t));
-  len = MultiByteToWideChar(CP_ACP, 0, serviceNameA, -1,
-                            serviceNameW, len);
-
-  if (len == 0){
-    wslLogText(L_ERROR, L"Unable to convert argument to unicode\n");
-    return NULL;
+  if (distributionName != NULL){
+    r = wslAtoW(distributionName, &distributionNameW);
+    if (r == -1)
+      return NULL;
+    else
+      instanceData->distributionName = distributionNameW;
   }
 
-  instanceData->command = serviceNameW;
-
-  //HANDLE handle = startWslServiceInteractive(serviceNameW, uid);
   HANDLE handle = startWslServiceInteractive(instanceData);
   //free(serviceNameW);
   return handle;
@@ -283,3 +279,30 @@ void wslRestoreUid(){
   return defaultDistW;
   }
 */
+
+int wslAtoW(LPCSTR input, LPWSTR *output){
+  if (input == NULL)
+    return -1;
+
+  int len = MultiByteToWideChar(CP_ACP, 0,
+                                input, -1,
+                                NULL, 0);
+
+  if (len == 0){
+    wslLogText(L_ERROR, L"Unable to get buffer length\n");
+    return -1;
+  }
+
+  *output = (LPWSTR)malloc(len * sizeof(wchar_t));
+
+  len = MultiByteToWideChar(CP_ACP, 0,
+                            input, -1,
+                            *output, len);
+
+  if (len == 0){
+    wslLogText(L_ERROR, L"Unable to convert argument to unicode\n");
+    return -1;
+  }
+
+  return len;
+}

wsl-launcher.h

@@ -27,23 +27,29 @@ struct _WslInstance{
 
 /** Start a service inside of WSL
  *
- * @param serviceName the name of a service. Must be configured on Linux side
- * @param uid the UID to use for the service
+ * @param instanceData instance configuration
  * @return a handle to the process running a non-interactive WSL instance
  */
-HANDLE startWslService(LPWSTR serviceName, ULONG uid);
+HANDLE startWslService(WslInstance *instanceData);
 /** Start an interactive service inside of WSL
  *
  * Typically using an interactive call in a service should be avoided, though
  * it is useful for interactive tools.
  *
- * @param serviceName the name of a service. Must be configured on Linux side
- * @param uid the UID to use for the service
+ * @param instanceData instance configuration
  * @return a handle to the thread running an interactive WSL instance
  */
 HANDLE startWslServiceInteractive(WslInstance *instanceData);
-/** A convenience wrapper around startWslServiceThreadInteractive, taking an
- * 8-bit string as argument, and converting it to wide.
+/** A convenience wrapper around startWslServiceThreadInteractive, taking
+ * 8-bit strings as argument, and converting it to wide.
+ *
+ * If any of serviceName or distributionName is not NULL it'll be converted
+ * to a wide string, and stuffed into instanceData.
+ *
+ * @param serviceName the name of the service. May only be NULL if instanceData.command is set
+ * @param distributionName the name of the distribution. May always be NULL
+ * @return a handle to the thread running an interactive WSL instance
+ *
  */
 HANDLE startWslServiceInteractiveA(LPCSTR serviceName, LPCSTR distributionName, WslInstance *instanceData);
 /** This implements the WSL service thread (i.e., a Windows thread wrapper
@@ -70,6 +76,14 @@ void wslSetRootUid();
 /** Restore a UID saved by wslSetRootUid
  */
 void wslRestoreUid();
-
+/** Convert a ASCII string to wide
+ *
+ * It's up to you to free the strings later.
+ *
+ * @param input the ASCII string to convert
+ * @param output a pointer to the wide string to receive the converted string
+ * @return -1 on error, otherwise the length of the string
+ */
+int wslAtoW(LPCSTR input, LPWSTR *output);
 
 #endif

wsl-tool.c

@@ -107,9 +107,10 @@ int main(int argc, char** argv){
   poptContext optCon;
 
   int optDefaultUid;
-  LPCWSTR optDistribution = NULL;
-  LPCWSTR optDistributionTar = NULL;
-  LPCWSTR optService = NULL;
+  LPCSTR optDistributionA = NULL;
+  LPWSTR optDistribution = NULL;
+  LPCSTR optDistributionTarA = NULL;
+  LPCSTR optServiceA = NULL;
 
   // distribution variables
   ULONG distVer, distUid;
@@ -146,11 +147,11 @@ int main(int argc, char** argv){
       "Export the distribution. Requires -d, -t and -p" },
     { "path", 'p', 0, 0, 'p',
       "The filesystem path to a distribution" },
-    { "tar", 't', POPT_ARG_STRING, &optDistributionTar, 't',
+    { "tar", 't', POPT_ARG_STRING, &optDistributionTarA, 't',
       "The tar file for export/import" },
-    { "run", 'r', POPT_ARG_STRING, &optService, 'r',
+    { "run", 'r', POPT_ARG_STRING, &optServiceA, 'r',
       "Run the service script" },
-    { "stop", 's', POPT_ARG_STRING, &optService, 's',
+    { "stop", 's', POPT_ARG_STRING, &optServiceA, 's',
       "Stop the service script" },
     { "setdefault", '\0', 0, 0, 'D',
       "Set the default distribution specified with -d" },
@@ -172,8 +173,14 @@ int main(int argc, char** argv){
   optCon = poptGetContext(NULL, argc, (const char **)argv, optionsTable, 0);
 
   // -d
-  if (optDistribution == NULL){
+  if (optDistributionA == NULL){
     optDistribution = defaultWslDistributionName();
+  } else {
+    int r = wslAtoW(optDistributionA, &optDistribution);
+    if (r == -1){
+      wprintf(L"Error during wide character conversion, bailing out...\n");
+      exit(1);
+    }
   }
 
   // following switches just copy arguments through popt, and don't need extra
@@ -232,8 +239,7 @@ int main(int argc, char** argv){
     case WSL_RUN:
       instanceData.uid = 0;
       instanceData.distributionName = optDistribution;
-      instanceData.command = optService;
-      HANDLE hThread = startWslServiceInteractive(&instanceData);
+      HANDLE hThread = startWslServiceInteractiveA(optServiceA, NULL, &instanceData);
       while(TRUE){
         DWORD result = WaitForSingleObject(hThread, INFINITE);
         if (result == WAIT_OBJECT_0){