diff --git a/usage.c b/usage.c index fd936a1aeb..b6aea45280 100644 --- a/usage.c +++ b/usage.c @@ -64,8 +64,24 @@ void die_errno(const char *fmt, ...) { va_list params; char fmt_with_err[1024]; + char str_error[256], *err; + int i, j; - snprintf(fmt_with_err, sizeof(fmt_with_err), "%s: %s", fmt, strerror(errno)); + err = strerror(errno); + for (i = j = 0; err[i] && j < sizeof(str_error) - 1; ) { + if ((str_error[j++] = err[i++]) != '%') + continue; + if (j < sizeof(str_error) - 1) { + str_error[j++] = '%'; + } else { + /* No room to double the '%', so we overwrite it with + * '\0' below */ + j--; + break; + } + } + str_error[j] = 0; + snprintf(fmt_with_err, sizeof(fmt_with_err), "%s: %s", fmt, str_error); va_start(params, fmt); die_routine(fmt_with_err, params);