PHPMailer::sendmailSend( string $header, string $body ): bool

1892    protected function sendmailSend($header, $body)1893    {1894        if ($this->Mailer === 'qmail') {1895            $this->edebug('Sending with qmail');1896        } else {1897            $this->edebug('Sending with sendmail');1898        }1899        $header = static::stripTrailingWSP($header) . static::$LE . static::$LE;1900        //This sets the SMTP envelope sender which gets turned into a return-path header by the receiver1901        //A space after `-f` is optional, but there is a long history of its presence1902        //causing problems, so we don't use one1903        //Exim docs: https://www.exim.org/exim-html-current/doc/html/spec_html/ch-the_exim_command_line.html1904        //Sendmail docs: https://www.sendmail.org/~ca/email/man/sendmail.html1905        //Example problem: https://www.drupal.org/node/10579541906 1907        //PHP 5.6 workaround1908        $sendmail_from_value = ini_get('sendmail_from');1909        if (empty($this->Sender) && !empty($sendmail_from_value)) {1910            //PHP config has a sender address we can use1911            $this->Sender = ini_get('sendmail_from');1912        }1913 1914        $sendmailArgs = [];1915 1916        // CVE-2016-10033, CVE-2016-10045: Don't pass -f if characters will be escaped.1917        // Also don't add the -f automatically unless it has been set either via Sender1918        // or sendmail_path. Otherwise, it can introduce new problems.1919        // @see http://github.com/PHPMailer/PHPMailer/issues/22981920        if (!empty($this->Sender) && static::validateAddress($this->Sender) && self::isShellSafe($this->Sender)) {1921            $sendmailArgs[] = '-f' . $this->Sender;1922        }1923 1924        // Qmail doesn't accept all the sendmail parameters1925        // @see https://github.com/PHPMailer/PHPMailer/issues/31891926        if ($this->Mailer !== 'qmail') {1927            $sendmailArgs[] = '-i';1928            $sendmailArgs[] = '-t';1929        }1930 1931        $resultArgs = (empty($sendmailArgs) ? '' : ' ' . implode(' ', $sendmailArgs));1932 1933        $sendmail = trim(escapeshellcmd($this->Sendmail) . $resultArgs);1934        $this->edebug('Sendmail path: ' . $this->Sendmail);1935        $this->edebug('Sendmail command: ' . $sendmail);1936        $this->edebug('Envelope sender: ' . $this->Sender);1937        $this->edebug("Headers: {$header}");1938 1939        if ($this->SingleTo) {1940            foreach ($this->SingleToArray as $toAddr) {1941                $mail = @popen($sendmail, 'w');1942                if (!$mail) {1943                    throw new Exception(self::lang('execute') . $this->Sendmail, self::STOP_CRITICAL);1944                }1945                $this->edebug("To: {$toAddr}");1946                fwrite($mail, 'To: ' . $toAddr . "\n");1947                fwrite($mail, $header);1948                fwrite($mail, $body);1949                $result = pclose($mail);1950                $addrinfo = static::parseAddresses($toAddr, null, $this->CharSet);1951                foreach ($addrinfo as $addr) {1952                    $this->doCallback(1953                        ($result === 0),1954                        [[$addr['address'], $addr['name']]],1955                        $this->cc,1956                        $this->bcc,1957                        $this->Subject,1958                        $body,1959                        $this->From,1960                        []1961                    );1962                }1963                $this->edebug("Result: " . ($result === 0 ? 'true' : 'false'));1964                if (0 !== $result) {1965                    throw new Exception(self::lang('execute') . $this->Sendmail, self::STOP_CRITICAL);1966                }1967            }1968        } else {1969            $mail = @popen($sendmail, 'w');1970            if (!$mail) {1971                throw new Exception(self::lang('execute') . $this->Sendmail, self::STOP_CRITICAL);