PHP内核-Apache2的SAPI

我们知道定义SAPI之前，首先要定义sapi_module_struct这个结构，相看源码：/soft/php-5.2.9/sapi/apache2handler/sapi_apache2.c，可以看到定义该结构，我直接复制过来：

static sapi_module_struct apache2_sapi_module = {        "apache2handler",        "Apache 2.0 Handler",        php_apache2_startup,                            /* startup */        php_module_shutdown_wrapper,                    /* shutdown */        NULL,                                           /* activate */        NULL,                                           /* deactivate */        php_apache_sapi_ub_write,                       /* unbuffered write */        php_apache_sapi_flush,                          /* flush */        php_apache_sapi_get_stat,                       /* get uid */        php_apache_sapi_getenv,                         /* getenv */        php_error,                                      /* error handler */        php_apache_sapi_header_handler,                 /* header handler */        php_apache_sapi_send_headers,                   /* send headers handler */        NULL,                                           /* send header handler */        php_apache_sapi_read_post,                      /* read POST data */        php_apache_sapi_read_cookies,                   /* read Cookies */        php_apache_sapi_register_variables,        php_apache_sapi_log_message,                    /* Log message */        php_apache_sapi_get_request_time,               /* Request Time */        STANDARD_SAPI_MODULE_PROPERTIES};

1，php_apache2_startup：当通过apache调用PHP时，这个函数会被调用。该函数定义如下，主要是对PHP进行初始化。

static int php_apache2_startup(sapi_module_struct *sapi_module){        if (php_module_startup(sapi_module, &php_apache_module, 1)==FAILURE) {                return FAILURE;        }        return SUCCESS;}

2，php_module_shutdown_wrapper ：PHP的关闭函数。

3，PHP会在每个request的时候，处理一些初始化，资源分配的事务。这部分就是activate字段要定义的。

4，与activate的函数，就是deactiveate，它会提供一个handler, 用来处理收尾工作。

5，php_apache_sapi_ub_write：提供一个向Response数据写的接口。

static intphp_apache_sapi_ub_write(const char *str, uint str_length TSRMLS_DC){        request_rec *r;        php_struct *ctx;        ctx = SG(server_context);        r = ctx->r;        if (ap_rwrite(str, str_length, r) < 0) {                php_handle_aborted_connection();        }        return str_length; /* we always consume all the data passed to us. */}

6，php_apache_sapi_flush：提供给zend刷新缓存的句柄。

static voidphp_apache_sapi_flush(void *server_context){        php_struct *ctx;        request_rec *r;        TSRMLS_FETCH();        ctx = server_context;        /* If we haven't registered a server_context yet,         * then don't bother flushing. */        if (!server_context) {                return;        }        r = ctx->r;        sapi_send_headers(TSRMLS_C);        r->status = SG(sapi_headers).http_response_code;        SG(headers_sent) = 1;        if (ap_rflush(r) < 0 || r->connection->aborted) {                php_handle_aborted_connection();        }}

7，php_apache_sapi_get_stat：这部分用来让Zend可以验证一个要执行脚本文件的state，从而判断文件是否据有执行权限等等。

static struct stat*php_apache_sapi_get_stat(TSRMLS_D){        php_struct *ctx = SG(server_context);        ctx->finfo.st_uid = ctx->r->finfo.user;        ctx->finfo.st_gid = ctx->r->finfo.group;        ctx->finfo.st_dev = ctx->r->finfo.device;        ctx->finfo.st_ino = ctx->r->finfo.inode;#if defined(NETWARE) && defined(CLIB_STAT_PATCH)        ctx->finfo.st_atime.tv_sec = apr_time_sec(ctx->r->finfo.atime);        ctx->finfo.st_mtime.tv_sec = apr_time_sec(ctx->r->finfo.mtime);        ctx->finfo.st_ctime.tv_sec = apr_time_sec(ctx->r->finfo.ctime);#else        ctx->finfo.st_atime = apr_time_sec(ctx->r->finfo.atime);        ctx->finfo.st_mtime = apr_time_sec(ctx->r->finfo.mtime);        ctx->finfo.st_ctime = apr_time_sec(ctx->r->finfo.ctime);#endif        ctx->finfo.st_size = ctx->r->finfo.size;        ctx->finfo.st_nlink = ctx->r->finfo.nlink;        return &ctx->finfo;}

8，php_apache_sapi_getenv：为Zend提供了一个根据name来查找环境变量的接口，当我们在脚本中调用getenv的时候，就会间接的调用这个句柄。

static char *php_apache_sapi_getenv(char *name, size_t name_len TSRMLS_DC){        php_struct *ctx = SG(server_context);        const char *env_var;        env_var = apr_table_get(ctx->r->subprocess_env, name);        return (char *) env_var;}

9，php_error：错误处理函数，直接调用PHP错误处理函数。

10，php_apache_sapi_header_handler：在调用PHP的header()函数时，会调用这个函数。

static intphp_apache_sapi_header_handler(sapi_header_struct *sapi_header,sapi_headers_struct *sapi_headers TSRMLS_DC){        php_struct *ctx;        char *val, *ptr;        ctx = SG(server_context);        val = strchr(sapi_header->header, ':');        if (!val) {                sapi_free_header(sapi_header);                return 0;        }        ptr = val;        *val = '\0';        do {                val++;        } while (*val == ' ');        if (!strcasecmp(sapi_header->header, "content-type")) {                if (ctx->content_type) {                        efree(ctx->content_type);                }                ctx->content_type = estrdup(val);        } else if (sapi_header->replace) {                apr_table_set(ctx->r->headers_out, sapi_header->header, val);        } else {                apr_table_add(ctx->r->headers_out, sapi_header->header, val);        }        *ptr = ':';        return SAPI_HEADER_ADD;}

11，php_apache_sapi_send_headers：当要真正发送header的时候，这个函数会被调用。

static intphp_apache_sapi_send_headers(sapi_headers_struct *sapi_headers TSRMLS_DC){        php_struct *ctx = SG(server_context);        const char *sline = SG(sapi_headers).http_status_line;        ctx->r->status = SG(sapi_headers).http_response_code;        /* httpd requires that r->status_line is set to the first digit of         * the status-code: */        if (sline && strlen(sline) > 12 && strncmp(sline, "HTTP/1.", 7) == 0 && sline[8] == ' ') {                ctx->r->status_line = apr_pstrdup(ctx->r->pool, sline + 9);                ctx->r->proto_num = 1000 + (sline[7]-'0');                if ((sline[7]-'0') == 0) {                        apr_table_set(ctx->r->subprocess_env, "force-response-1.0", "true");                }        }        /*      call ap_set_content_type only once, else each time we call it,                configured output filters for that content type will be added */        if (!ctx->content_type) {                ctx->content_type = sapi_get_default_content_type(TSRMLS_C);        }        ap_set_content_type(ctx->r, apr_pstrdup(ctx->r->pool, ctx->content_type));        efree(ctx->content_type);        ctx->content_type = NULL;        return SAPI_HEADER_SENT_SUCCESSFULLY;}

12，在php_apache_sapi_send_headers指针下面有一个域，用来指明发送每一个单独的header时调用。

13，php_apache_sapi_read_post：表示如何读取POST数据。

static int php_apache_sapi_read_post(char *buf, uint count_bytes TSRMLS_DC){        apr_size_t len, tlen=0;        php_struct *ctx = SG(server_context);        request_rec *r;        apr_bucket_brigade *brigade;        r = ctx->r;        brigade = ctx->brigade;        len = count_bytes;        /*         * This loop is needed because ap_get_brigade() can return us partial data         * which would cause premature termination of request read. Therefor we         * need to make sure that if data is available we fill the buffer completely.         */        while (ap_get_brigade(r->input_filters, brigade, AP_MODE_READBYTES, APR_BLOCK_READ, len) == APR_SUCCESS) {                apr_brigade_flatten(brigade, buf, &len);                apr_brigade_cleanup(brigade);                tlen += len;                if (tlen == count_bytes || !len) {                        break;                }                buf += len;                len = count_bytes - tlen;        }        return tlen;}

14，php_apache_sapi_read_cookie：如何读取cookie。

static char *php_apache_sapi_read_cookies(TSRMLS_D){        php_struct *ctx = SG(server_context);        const char *http_cookie;        http_cookie = apr_table_get(ctx->r->headers_in, "cookie");        /* The SAPI interface should use 'const char *' */        return (char *) http_cookie;}

15，php_apache_sapi_register_variables：提供接口，用于给$_SERVER[]数组提供变量。

static voidphp_apache_sapi_register_variables(zval *track_vars_array TSRMLS_DC){        php_struct *ctx = SG(server_context);        const apr_array_header_t *arr = apr_table_elts(ctx->r->subprocess_env);        char *key, *val;        int new_val_len;        APR_ARRAY_FOREACH_OPEN(arr, key, val)                if (!val) {                        val = "";                }                if (sapi_module.input_filter(PARSE_SERVER, key, &val, strlen(val), &new_val_len TSRMLS_CC)) {                        php_register_variable_safe(key, val, new_val_len, track_vars_array TSRMLS_CC);                }        APR_ARRAY_FOREACH_CLOSE()        if (sapi_module.input_filter(PARSE_SERVER, "PHP_SELF", &ctx->r->uri, strlen(ctx->r->uri), &new_val_len TSRMLS_CC)) {                php_register_variable_safe("PHP_SELF", ctx->r->uri, new_val_len, track_vars_array TSRMLS_CC);        }}

16，php_apache_sapi_log_message：输出错误信息。

static void php_apache_sapi_log_message(char *msg){        php_struct *ctx;        TSRMLS_FETCH();        ctx = SG(server_context);        if (ctx == NULL) { /* we haven't initialized our ctx yet, oh well */                ap_log_error(APLOG_MARK, APLOG_ERR | APLOG_STARTUP, 0, NULL, "%s", msg);        } else {                ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, ctx->r, "%s", msg);        }}

17，php_apache_sapi_get_request_time：获取请求时间。

static time_t php_apache_sapi_get_request_time(TSRMLS_D) {        php_struct *ctx = SG(server_context);        return apr_time_sec(ctx->r->request_time);}

这就完成了apache的SAPI定义。之后，就是当用户用URL请求apache服务，这些函数指针就会在适当的时候，发挥作用了（被调用）。