489     /* gamma launcher uses JAVA_HOME or ALT_JAVA_HOME environment variable to find JDK/JRE */

   490     char env[MAXPATHLEN + 1];

   490     char* java_home_var = getenv("ALT_JAVA_HOME");

   491 

   491     if (java_home_var == NULL) {

   492     /* gamma launcher uses ALT_JAVA_HOME environment variable or jdkpath.txt file to find JDK/JRE */

   492        java_home_var = getenv("JAVA_HOME");

   493 

   493     }

   494     if (getenv("ALT_JAVA_HOME") != NULL) {

   494     if (java_home_var == NULL) {

   495        snprintf(buf, bufsize, "%s", getenv("ALT_JAVA_HOME"));

   495        printf("JAVA_HOME or ALT_JAVA_HOME must point to a valid JDK/JRE to run gamma\n");

   496     }

   496        return JNI_FALSE;

   497     else {

   497     }

   498        char path[MAXPATHLEN + 1];

   498     snprintf(buf, bufsize, "%s", java_home_var);

   499        char* p;

   500        int len;

   501        FILE* fp;

   502 

   503        // find the path to the currect executable

   504        len = GetModuleFileName(NULL, path, MAXPATHLEN + 1);

   505        if (len == 0 || len > MAXPATHLEN) {

   506           printf("Could not get directory of current executable.");

   507           return JNI_FALSE;

   508        }

   509        // remove last path component ("hotspot.exe")

   510        p = strrchr(path, '\\');

   511        if (p == NULL) {

   512           printf("Could not parse directory of current executable.\n");

   513           return JNI_FALSE;

   514        }

   515        *p = '\0';

   516 

   517        // open jdkpath.txt and read JAVA_HOME from it

   518        if (strlen(path) + strlen("\\jdkpath.txt") + 1 >= MAXPATHLEN) {

   519           printf("Path too long: %s\n", path);

   520           return JNI_FALSE;

   521        }

   522        strcat(path, "\\jdkpath.txt");

   523        fp = fopen(path, "r");

   524        if (fp == NULL) {

   525           printf("Could not open file %s to get path to JDK.\n", path);

   526           return JNI_FALSE;

   527        }

   528 

   529        if (fgets(buf, bufsize, fp) == NULL) {

   530           printf("Could not read from file %s to get path to JDK.\n", path);

   531           fclose(fp);

   532           return JNI_FALSE;

   533        }

   534        // trim the buffer

   535        p = buf + strlen(buf) - 1;

   536        while(isspace(*p)) {

   537           *p = '\0';

   538           p--;

   539        }

   540        fclose(fp);

   541     }

   542 

   543     _snprintf(env, MAXPATHLEN, "JAVA_HOME=%s", buf);

   544     _putenv(env);

   545