+ STRUCT_STAT st;
+ char buffer[512], *p;
+ int fd, n, ok = 1;
+ const char *envpw = getenv("RSYNC_PASSWORD");
+
+ if (!filename)
+ return NULL;
+
+ if ((fd = open(filename,O_RDONLY)) < 0) {
+ rsyserr(FERROR, errno, "could not open password file \"%s\"",
+ filename);
+ if (envpw)
+ rprintf(FERROR, "falling back to RSYNC_PASSWORD environment variable.\n");
+ return NULL;
+ }
+
+ if (do_stat(filename, &st) == -1) {
+ rsyserr(FERROR, errno, "stat(%s)", filename);
+ ok = 0;
+ } else if ((st.st_mode & 06) != 0) {
+ rprintf(FERROR,"password file must not be other-accessible\n");
+ ok = 0;
+ } else if (MY_UID() == 0 && st.st_uid != 0) {
+ rprintf(FERROR,"password file must be owned by root when running as root\n");
+ ok = 0;
+ }
+ if (!ok) {
+ rprintf(FERROR,"continuing without password file\n");
+ if (envpw)
+ rprintf(FERROR, "using RSYNC_PASSWORD environment variable.\n");
+ close(fd);
+ return NULL;
+ }
+
+ if (envpw)
+ rprintf(FERROR, "RSYNC_PASSWORD environment variable ignored\n");
+
+ n = read(fd, buffer, sizeof buffer - 1);
+ close(fd);
+ if (n > 0) {
+ buffer[n] = '\0';
+ if ((p = strtok(buffer, "\n\r")) != NULL)
+ return strdup(p);
+ }
+
+ return NULL;
+}
+
+/* Generate an MD4 hash created from the combination of the password
+ * and the challenge string and return it base64-encoded. */
+static void generate_hash(const char *in, const char *challenge, char *out)
+{
+ char buf[MD4_SUM_LENGTH];