#define FUNCTION      "-function"
 #define NOFUNCTION    "-nofunction"
 
+char *srctree;
+
 void usage (void)
 {
        fprintf(stderr, "Usage: docproc {doc|depend} file\n");
        fprintf(stderr, "Input is read from file.tmpl. Output is sent to stdout\n");
        fprintf(stderr, "doc: frontend when generating kernel documentation\n");
        fprintf(stderr, "depend: generate list of files referenced within file\n");
+       fprintf(stderr, "Environment variable SRCTREE: absolute path to kernel source tree.\n");
 }
 
 /*
                        exit(1);
                case  0:
                        memset(real_filename, 0, sizeof(real_filename));
-                       strncat(real_filename, getenv("SRCTREE"), PATH_MAX);
+                       strncat(real_filename, srctree, PATH_MAX);
                        strncat(real_filename, KERNELDOCPATH KERNELDOC,
                                        PATH_MAX - strlen(real_filename));
                        execvp(real_filename, svec);
        if (filename_exist(filename) == NULL) {
                char real_filename[PATH_MAX + 1];
                memset(real_filename, 0, sizeof(real_filename));
-               strncat(real_filename, getenv("SRCTREE"), PATH_MAX);
+               strncat(real_filename, srctree, PATH_MAX);
                strncat(real_filename, filename,
                                PATH_MAX - strlen(real_filename));
                sym = add_new_file(filename);
 int main(int argc, char *argv[])
 {
        FILE * infile;
+
+       srctree = getenv("SRCTREE");
+       if (!srctree)
+               srctree = getcwd(NULL, 0);
        if (argc != 3) {
                usage();
                exit(1);