深入理解Zend SAPIs(Zend SAPI Internals)

   static int php_cgi_startup(sapi_module_struct *sapi_module)
{
    if (php_module_startup(sapi_module, NULL, 0) == FAILURE) {
        return FAILURE;
    }
    return SUCCESS;
}
   

  static int sapi_cgi_deactivate(TSRMLS_D)
{
    /* flush only when SAPI was started. The reasons are:
        1. SAPI Deactivate is called from two places: module init and request shutdown
        2. When the first call occurs and the request is not set up, flush fails on
            FastCGI.
    */
    if (SG(sapi_started)) {
        sapi_cgibin_flush(SG(server_context));
    }
    return SUCCESS;
}

static inline size_t sapi_cgibin_single_write(const char *str, uint str_length TSRMLS_DC)
{
#ifdef PHP_WRITE_STDOUT
    long ret;
#else
    size_t ret;
#endif
#if PHP_FASTCGI
    if (fcgi_is_fastcgi()) {
        fcgi_request *request = (fcgi_request*) SG(server_context);
        long ret = fcgi_write(request, FCGI_STDOUT, str, str_length);
        if (ret <= 0) {
            return 0;
        }
        return ret;
    }
#endif
#ifdef PHP_WRITE_STDOUT
    ret = write(STDOUT_FILENO, str, str_length);
    if (ret <= 0) return 0;
    return ret;
#else
    ret = fwrite(str, 1, MIN(str_length, 16384), stdout);
    return ret;
#endif
}
static int sapi_cgibin_ub_write(const char *str, uint str_length TSRMLS_DC)
{
    const char *ptr = str;
    uint remaining = str_length;
    size_t ret;
    while (remaining > 0) {
        ret = sapi_cgibin_single_write(ptr, remaining TSRMLS_CC);
        if (!ret) {
            php_handle_aborted_connection();
            return str_length - remaining;
        }
        ptr += ret;
        remaining -= ret;
    }
    return str_length;
}

把真正的写的逻辑剥离出来，就是为了简单实现兼容fastcgi的写方式。

static char *sapi_cgibin_getenv(char *name, size_t name_len TSRMLS_DC)
{
#if PHP_FASTCGI
    /* when php is started by mod_fastcgi, no regular environment
       is provided to PHP.  It is always sent to PHP at the start
       of a request.  So we have to do our own lookup to get env
       vars.  This could probably be faster somehow.  */
    if (fcgi_is_fastcgi()) {
        fcgi_request *request = (fcgi_request*) SG(server_context);
        return fcgi_getenv(request, name, name_len);
    }
#endif
    /*  if cgi, or fastcgi and not found in fcgi env
        check the regular environment */
    return getenv(name);
}

static int sapi_cgi_send_headers(sapi_headers_struct *sapi_headers TSRMLS_DC)
{
    char buf[SAPI_CGI_MAX_HEADER_LENGTH];
    sapi_header_struct *h;
    zend_llist_position pos;
    if (SG(request_info).no_headers == 1) {
        return  SAPI_HEADER_SENT_SUCCESSFULLY;
    }
    if (cgi_nph || SG(sapi_headers).http_response_code != 200)
    {
        int len;
        if (rfc2616_headers && SG(sapi_headers).http_status_line) {
            len = snprintf(buf, SAPI_CGI_MAX_HEADER_LENGTH,
                           "%s\r\n", SG(sapi_headers).http_status_line);
            if (len > SAPI_CGI_MAX_HEADER_LENGTH) {
                len = SAPI_CGI_MAX_HEADER_LENGTH;
            }
        } else {
            len = sprintf(buf, "Status: %d\r\n", SG(sapi_headers).http_response_code);
        }
        PHPWRITE_H(buf, len);
    }
    h = (sapi_header_struct*)zend_llist_get_first_ex(&sapi_headers->headers, &pos);
    while (h) {
        /* prevent CRLFCRLF */
        if (h->header_len) {
            PHPWRITE_H(h->header, h->header_len);
            PHPWRITE_H("\r\n", 2);
        }
        h = (sapi_header_struct*)zend_llist_get_next_ex(&sapi_headers->headers, &pos);
    }
    PHPWRITE_H("\r\n", 2);
    return SAPI_HEADER_SENT_SUCCESSFULLY;
   }
  

static int sapi_cgi_read_post(char *buffer, uint count_bytes TSRMLS_DC)
{
    uint read_bytes=0, tmp_read_bytes;
#if PHP_FASTCGI
    char *pos = buffer;
#endif
    count_bytes = MIN(count_bytes, (uint) SG(request_info).content_length - SG(read_post_bytes));
    while (read_bytes < count_bytes) {
#if PHP_FASTCGI
        if (fcgi_is_fastcgi()) {
            fcgi_request *request = (fcgi_request*) SG(server_context);
            tmp_read_bytes = fcgi_read(request, pos, count_bytes - read_bytes);
            pos += tmp_read_bytes;
        } else {
            tmp_read_bytes = read(0, buffer + read_bytes, count_bytes - read_bytes);
        }
#else
        tmp_read_bytes = read(0, buffer + read_bytes, count_bytes - read_bytes);
#endif
        if (tmp_read_bytes <= 0) {
            break;
        }
        read_bytes += tmp_read_bytes;
    }
    return read_bytes;
}

static char *sapi_cgi_read_cookies(TSRMLS_D)
{
    return sapi_cgibin_getenv((char *) "HTTP_COOKIE", sizeof("HTTP_COOKIE")-1 TSRMLS_CC);
}

static void sapi_cgi_register_variables(zval *track_vars_array TSRMLS_DC)
{
    /* In CGI mode, we consider the environment to be a part of the server
     * variables
     */
    php_import_environment_variables(track_vars_array TSRMLS_CC);
    /* Build the special-case PHP_SELF variable for the CGI version */
    php_register_variable("PHP_SELF", (SG(request_info).request_uri ? SG(request_info).request_uri : ""), track_vars_array TSRMLS_CC);
}

static void sapi_cgi_log_message(char *message)
{
#if PHP_FASTCGI
    if (fcgi_is_fastcgi() && fcgi_logging) {
        fcgi_request *request;
        TSRMLS_FETCH();
        request = (fcgi_request*) SG(server_context);
        if (request) {
            int len = strlen(message);
            char *buf = malloc(len+2);
            memcpy(buf, message, len);
            memcpy(buf + len, "\n", sizeof("\n"));
            fcgi_write(request, FCGI_STDERR, buf, len+1);
            free(buf);
        } else {
            fprintf(stderr, "%s\n", message);
        }
        /* ignore return code */
    } else
#endif /* PHP_FASTCGI */
    fprintf(stderr, "%s\n", message);
}