+ struct subprocess *chp;
+ struct stat sbuf;
+
+ /*
+ * First check if the file exists and is executable.
+ * We don't use access() because that would use the
+ * real user-id, which might not be root, and the script
+ * might be accessible only to root.
+ */
+ errno = EINVAL;
+ if (stat(prog, &sbuf) < 0 || !S_ISREG(sbuf.st_mode)
+ || (sbuf.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0) {
+ if (must_exist || errno != ENOENT)
+ syslog(LOG_WARNING, "Can't execute %s: %m", prog);
+ return 0;
+ }