Add launcher util for AppImage

utils/launcher.cpp

@@ -0,0 +1,40 @@
+#include <iostream>
+#include <unistd.h>
+#include <libgen.h>
+#include <string.h>
+
+#include "utils_common.h"
+
+#ifndef DEFAULT_UTIL
+#define DEFAULT_UTIL "acsmdownloader"
+#endif
+
+/* Inspired from https://discourse.appimage.org/t/call-alternative-binary-from-appimage/93/10*/
+
+int main(int argc, char** argv)
+{
+    char* util, *argv0;
+    char* mountPoint = getenv("APPDIR");
+    std::string fullPath;
+
+    /* Original command is in ARGV0 env variable*/
+    argv0 = strdup(getenv("ARGV0"));
+    util = basename(argv0);
+
+    fullPath = std::string(mountPoint) + util;
+
+    if (std::string(util) == "launcher" || !fileExists(fullPath.c_str()))
+	fullPath = std::string(mountPoint) + DEFAULT_UTIL;
+
+    free(argv0);
+    
+    argv[0] = strdup(fullPath.c_str());
+
+    if (execvp(argv[0], argv))
+	std::cout << "Unable to launch '" << argv[0] << "'" << std::endl;
+
+    /* Should not happens */
+    free(argv[0]);
+    
+    return 0;
+}