GUACAMOLE-1174: Added exec call implementation for kubernetes protocol

src/protocols/kubernetes/kubernetes.c

@@ -213,10 +213,12 @@ void* guac_kubernetes_client_thread(void* data) {
     }
 
     /* Generate endpoint for attachment URL */
-    if (guac_kubernetes_endpoint_attach(endpoint_path, sizeof(endpoint_path),
+    if (guac_kubernetes_endpoint_uri(endpoint_path, sizeof(endpoint_path),
                 settings->kubernetes_namespace,
                 settings->kubernetes_pod,
-                settings->kubernetes_container)) {
+                settings->kubernetes_container,
+                settings->use_exec,
+                settings->exec_command)) {
         guac_client_abort(client, GUAC_PROTOCOL_STATUS_SERVER_ERROR,
                 "Unable to generate path for Kubernetes API endpoint: "
                 "Resulting path too long");

src/protocols/kubernetes/settings.c

@@ -31,6 +31,8 @@ const char* GUAC_KUBERNETES_CLIENT_ARGS[] = {
     "namespace",
     "pod",
     "container",
+    "use-exec",
+    "exec-command",
     "use-ssl",
     "client-cert",
     "client-key",
@@ -86,6 +88,16 @@ enum KUBERNETES_ARGS_IDX {
      */
     IDX_CONTAINER,
 
+    /**
+     * Whether exec call should be used. If omitted, attach call will be used.
+     */
+    IDX_USE_EXEC,
+
+    /**
+     * The command used by exec call.
+     */
+    IDX_EXEC_COMMAND,
+
     /**
      * Whether SSL/TLS should be used. If omitted, SSL/TLS will not be used.
      */
@@ -275,6 +287,16 @@ guac_kubernetes_settings* guac_kubernetes_parse_args(guac_user* user,
         guac_user_parse_args_string(user, GUAC_KUBERNETES_CLIENT_ARGS, argv,
                 IDX_CONTAINER, NULL);
 
+    /* Parse whether exec call should be used */
+    settings->use_exec =
+        guac_user_parse_args_boolean(user, GUAC_KUBERNETES_CLIENT_ARGS, argv,
+                IDX_USE_EXEC, false);
+
+    /* Read exec command (optional) */
+    settings->exec_command =
+        guac_user_parse_args_string(user, GUAC_KUBERNETES_CLIENT_ARGS, argv,
+                IDX_EXEC_COMMAND, GUAC_KUBERNETES_DEFAULT_EXEC_COMMAND);
+
     /* Parse whether SSL should be used */
     settings->use_ssl =
         guac_user_parse_args_boolean(user, GUAC_KUBERNETES_CLIENT_ARGS, argv,

src/protocols/kubernetes/settings.h

@@ -47,6 +47,12 @@
  */
 #define GUAC_KUBERNETES_DEFAULT_NAMESPACE "default"
 
+/**
+ * The command that should be used by default for exec call if no
+ * specific command is provided.
+ */
+#define GUAC_KUBERNETES_DEFAULT_EXEC_COMMAND "/bin/sh"
+
 /**
  * The filename to use for the typescript, if not specified.
  */
@@ -97,6 +103,16 @@ typedef struct guac_kubernetes_settings {
      */
     char* kubernetes_container;
 
+    /**
+     * Whether exec call should be used, default attach.
+     */
+    bool use_exec;
+
+    /**
+     * Exec command, default /bin/sh.
+     */
+    char* exec_command;
+
     /**
      * Whether SSL/TLS should be used.
      */

src/protocols/kubernetes/url.c

@@ -89,15 +89,16 @@ int guac_kubernetes_escape_url_component(char* output, int length,
 
 }
 
-int guac_kubernetes_endpoint_attach(char* buffer, int length,
+int guac_kubernetes_endpoint_uri(char* buffer, int length,
         const char* kubernetes_namespace, const char* kubernetes_pod,
-        const char* kubernetes_container) {
+        const char* kubernetes_container, int use_exec, const char* exec_command) {
 
     int written;
 
     char escaped_namespace[GUAC_KUBERNETES_MAX_ENDPOINT_LENGTH];
     char escaped_pod[GUAC_KUBERNETES_MAX_ENDPOINT_LENGTH];
     char escaped_container[GUAC_KUBERNETES_MAX_ENDPOINT_LENGTH];
+    char escaped_exec_command[GUAC_KUBERNETES_MAX_ENDPOINT_LENGTH];
 
     /* Escape Kubernetes namespace */
     if (guac_kubernetes_escape_url_component(escaped_namespace,
@@ -109,26 +110,42 @@ int guac_kubernetes_endpoint_attach(char* buffer, int length,
                 sizeof(escaped_pod), kubernetes_pod))
         return 1;
 
-    /* Generate attachment endpoint URL */
+    /* Generate endpoint path depending on the call type */
-    if (kubernetes_container != NULL) {
+    char* call="attach";
+    if (use_exec)
+        call = "exec";
 
+    char endpoint_path[GUAC_KUBERNETES_MAX_ENDPOINT_LENGTH];
+    snprintf(endpoint_path, GUAC_KUBERNETES_MAX_ENDPOINT_LENGTH*3, 
+    "/api/v1/namespaces/%s/pods/%s/%s", escaped_namespace, escaped_pod, call);
+
+    /* Generate endpoint params */
+    char endpoint_params[GUAC_KUBERNETES_MAX_ENDPOINT_LENGTH]="";
+    int param_length=0;
+
+    if(use_exec){
+        /* Escape exec command */
+        if (guac_kubernetes_escape_url_component(escaped_exec_command,
+                    sizeof(escaped_exec_command), exec_command))
+            return 1;
+
+        param_length += snprintf(endpoint_params, GUAC_KUBERNETES_MAX_ENDPOINT_LENGTH, 
+        "command=%s&", escaped_exec_command);
+    }
+
+    if (kubernetes_container != NULL) {
         /* Escape container name */
         if (guac_kubernetes_escape_url_component(escaped_container,
                     sizeof(escaped_container), kubernetes_container))
             return 1;
 
-        written = snprintf(buffer, length,
+        snprintf(endpoint_params+param_length, GUAC_KUBERNETES_MAX_ENDPOINT_LENGTH-param_length,
-                "/api/v1/namespaces/%s/pods/%s/attach"
+                "container=%s&", escaped_container);
-                "?container=%s&stdin=true&stdout=true&tty=true",
-                escaped_namespace, escaped_pod, escaped_container);
-    }
-    else {
-        written = snprintf(buffer, length,
-                "/api/v1/namespaces/%s/pods/%s/attach"
-                "?stdin=true&stdout=true&tty=true",
-                escaped_namespace, escaped_pod);
     }
 
+    /* Combine path and params to uri */
+    written = snprintf(buffer, length, "%s?%sstdin=true&stdout=true&tty=true", 
+    endpoint_path, endpoint_params);
     /* Endpoint URL was successfully generated if it was written to the given
      * buffer without truncation */
     return !(written < length - 1);

src/protocols/kubernetes/url.h

@@ -72,14 +72,21 @@ int guac_kubernetes_escape_url_component(char* output, int length,
  * @param kubernetes_container
  *     The name of the container to attach to, or NULL to arbitrarily attach
  *     to the first container in the pod.
+ * 
+ * @param use_exec
+ *     Whether use call exec.
+ *     Execute a command in a container and attach to it instead of main container process.
+ * 
+ * @param exec_command
+ *     The command used in conjunction with exec call.
  *
  * @return
  *     Zero if the endpoint path was successfully written to the provided
  *     buffer, non-zero if insufficient space exists within the buffer.
  */
-int guac_kubernetes_endpoint_attach(char* buffer, int length,
+int guac_kubernetes_endpoint_uri(char* buffer, int length,
         const char* kubernetes_namespace, const char* kubernetes_pod,
-        const char* kubernetes_container);
+        const char* kubernetes_container, int use_exec, const char* exec_command);
 
 #endif