mod_log_config.c

Apache HTTP Server 是一个功能强大的灵活的与HTTP/1.1相兼容的web服务器.这里给出的是Apache HTTP服务器的源码。

/* Copyright 1999-2005 The Apache Software Foundation or its licensors, as
 * applicable.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * Modified by [e-mail]:
 * If no TransferLog is given explicitly, decline to log.
 *
 * This is module implements the TransferLog directive (same as the
 * common log module), and additional directives, LogFormat and CustomLog.
 *
 *
 * Syntax:
 *
 *    TransferLog fn      Logs transfers to fn in standard log format, unless
 *                        a custom format is set with LogFormat
 *    LogFormat format    Set a log format from TransferLog files
 *    CustomLog fn format
 *                        Log to file fn with format given by the format
 *                        argument
 *
 *    CookieLog fn        For backwards compatability with old Cookie
 *                        logging module - now deprecated.
 *
 * There can be any number of TransferLog and CustomLog
 * commands. Each request will be logged to _ALL_ the
 * named files, in the appropriate format.
 *
 * If no TransferLog or CustomLog directive appears in a VirtualHost,
 * the request will be logged to the log file(s) defined outside
 * the virtual host section. If a TransferLog or CustomLog directive
 * appears in the VirtualHost section, the log files defined outside
 * the VirtualHost will _not_ be used. This makes this module compatable
 * with the CLF and config log modules, where the use of TransferLog
 * inside the VirtualHost section overrides its use outside.
 * 
 * Examples:
 *
 *    TransferLog    logs/access_log
 *    <VirtualHost>
 *    LogFormat      "... custom format ..."
 *    TransferLog    log/virtual_only
 *    CustomLog      log/virtual_useragents "%t %{user-agent}i"
 *    </VirtualHost>
 *
 * This will log using CLF to access_log any requests handled by the
 * main server, while any requests to the virtual host will be logged
 * with the "... custom format..." to virtual_only _AND_ using
 * the custom user-agent log to virtual_useragents.
 *
 * Note that the NCSA referer and user-agent logs are easily added with
 * CustomLog:
 *   CustomLog   logs/referer  "%{referer}i -> %U"
 *   CustomLog   logs/agent    "%{user-agent}i"
 *
 * RefererIgnore functionality can be obtained with conditional
 * logging (SetEnvIf and CustomLog ... env=!VAR).
 *
 * But using this method allows much easier modification of the
 * log format, e.g. to log hosts along with UA:
 *   CustomLog   logs/referer "%{referer}i %U %h"
 *
 * The argument to LogFormat and CustomLog is a string, which can include
 * literal characters copied into the log files, and '%' directives as
 * follows:
 *
 * %...B:  bytes sent, excluding HTTP headers.
 * %...b:  bytes sent, excluding HTTP headers in CLF format, i.e. a '-'
 *         when no bytes where sent (rather than a '0'.
 * %...{FOOBAR}C:  The contents of the HTTP cookie FOOBAR
 * %...{FOOBAR}e:  The contents of the environment variable FOOBAR
 * %...f:  filename
 * %...h:  remote host
 * %...a:  remote IP-address
 * %...A:  local IP-address
 * %...{Foobar}i:  The contents of Foobar: header line(s) in the request
 *                 sent to the client.
 * %...l:  remote logname (from identd, if supplied)
 * %...{Foobar}n:  The contents of note "Foobar" from another module.
 * %...{Foobar}o:  The contents of Foobar: header line(s) in the reply.
 * %...p:  the port the request was served to
 * %...P:  the process ID of the child that serviced the request.
 * %...{format}P: the process ID or thread ID of the child/thread that
 *                serviced the request
 * %...r:  first line of request
 * %...s:  status.  For requests that got internally redirected, this
 *         is status of the *original* request --- %...>s for the last.
 * %...t:  time, in common log format time format
 * %...{format}t:  The time, in the form given by format, which should
 *                 be in strftime(3) format.
 * %...T:  the time taken to serve the request, in seconds.
 * %...D:  the time taken to serve the request, in micro seconds.
 * %...u:  remote user (from auth; may be bogus if return status (%s) is 401)
 * %...U:  the URL path requested.
 * %...v:  the configured name of the server (i.e. which virtual host?)
 * %...V:  the server name according to the UseCanonicalName setting
 * %...m:  the request method
 * %...H:  the request protocol
 * %...q:  the query string prepended by "?", or empty if no query string
 * %...X:  Status of the connection.
 *         'X' = connection aborted before the response completed.
 *         '+' = connection may be kept alive after the response is sent.
 *         '-' = connection will be closed after the response is sent.
           (This directive was %...c in late versions of Apache 1.3, but
            this conflicted with the historical ssl %...{var}c syntax.)
*
 * The '...' can be nothing at all (e.g. "%h %u %r %s %b"), or it can
 * indicate conditions for inclusion of the item (which will cause it
 * to be replaced with '-' if the condition is not met).  Note that
 * there is no escaping performed on the strings from %r, %...i and
 * %...o; some with long memories may remember that I thought this was
 * a bad idea, once upon a time, and I'm still not comfortable with
 * it, but it is difficult to see how to "do the right thing" with all
 * of '%..i', unless we URL-escape everything and break with CLF.
 *
 * The forms of condition are a list of HTTP status codes, which may
 * or may not be preceded by '!'.  Thus, '%400,501{User-agent}i' logs
 * User-agent: on 400 errors and 501 errors (Bad Request, Not
 * Implemented) only; '%!200,304,302{Referer}i' logs Referer: on all
 * requests which did *not* return some sort of normal status.
 *
 * The default LogFormat reproduces CLF; see below.
 *
 * The way this is supposed to work with virtual hosts is as follows:
 * a virtual host can have its own LogFormat, or its own TransferLog.
 * If it doesn't have its own LogFormat, it inherits from the main
 * server.  If it doesn't have its own TransferLog, it writes to the
 * same descriptor (meaning the same process for "| ...").
 *
 * --- rst */

#include "apr_strings.h"
#include "apr_lib.h"
#include "apr_hash.h"
#include "apr_optional.h"
#include "apr_anylock.h"

#define APR_WANT_STRFUNC
#include "apr_want.h"

#include "ap_config.h"
#include "mod_log_config.h"
#include "httpd.h"
#include "http_config.h"
#include "http_core.h"          /* For REMOTE_NAME */
#include "http_log.h"
#include "http_protocol.h"
#include "util_time.h"
#include "ap_mpm.h"

#if APR_HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif

#define DEFAULT_LOG_FORMAT "%h %l %u %t \"%r\" %>s %b"

module AP_MODULE_DECLARE_DATA log_config_module;

#ifndef APR_LARGEFILE
#define APR_LARGEFILE 0
#endif

static int xfer_flags = (APR_WRITE | APR_APPEND | APR_CREATE | APR_LARGEFILE);
static apr_fileperms_t xfer_perms = APR_OS_DEFAULT;
static apr_hash_t *log_hash;
static apr_status_t ap_default_log_writer(request_rec *r,
                           void *handle, 
                           const char **strs,
                           int *strl,
                           int nelts,
                           apr_size_t len);
static apr_status_t ap_buffered_log_writer(request_rec *r,
                           void *handle, 
                           const char **strs,
                           int *strl,
                           int nelts,
                           apr_size_t len);
static void *ap_default_log_writer_init(apr_pool_t *p, server_rec *s, 
                                        const char* name);
static void *ap_buffered_log_writer_init(apr_pool_t *p, server_rec *s, 
                                        const char* name);

static void ap_log_set_writer_init(ap_log_writer_init *handle);
static void ap_log_set_writer(ap_log_writer *handle);
static ap_log_writer *log_writer = ap_default_log_writer;
static ap_log_writer_init *log_writer_init = ap_default_log_writer_init;
static int buffered_logs = 0; /* default unbuffered */
static apr_array_header_t *all_buffered_logs = NULL;

/* POSIX.1 defines PIPE_BUF as the maximum number of bytes that is
 * guaranteed to be atomic when writing a pipe.  And PIPE_BUF >= 512
 * is guaranteed.  So we'll just guess 512 in the event the system
 * doesn't have this.  Now, for file writes there is actually no limit,
 * the entire write is atomic.  Whether all systems implement this
 * correctly is another question entirely ... so we'll just use PIPE_BUF
 * because it's probably a good guess as to what is implemented correctly
 * everywhere.
 */
#ifdef PIPE_BUF
#define LOG_BUFSIZE     PIPE_BUF
#else
#define LOG_BUFSIZE     (512)
#endif

/*
 * multi_log_state is our per-(virtual)-server configuration. We store
 * an array of the logs we are going to use, each of type config_log_state.
 * If a default log format is given by LogFormat, store in default_format
 * (backward compat. with mod_log_config).  We also store for each virtual
 * server a pointer to the logs specified for the main server, so that if this
 * vhost has no logs defined, we can use the main server's logs instead.
 *
 * So, for the main server, config_logs contains a list of the log files
 * and server_config_logs is empty. For a vhost, server_config_logs
 * points to the same array as config_logs in the main server, and
 * config_logs points to the array of logs defined inside this vhost,
 * which might be empty.
 */

typedef struct {
    const char *default_format_string;
    apr_array_header_t *default_format;
    apr_array_header_t *config_logs;
    apr_array_header_t *server_config_logs;
    apr_table_t *formats;
} multi_log_state;

/*
 * config_log_state holds the status of a single log file. fname might
 * be NULL, which means this module does no logging for this
 * request. format might be NULL, in which case the default_format
 * from the multi_log_state should be used, or if that is NULL as
 * well, use the CLF. 
 * log_writer is NULL before the log file is opened and is
 * set to a opaque structure (usually a fd) after it is opened.
 
 */
typedef struct {
    apr_file_t *handle;
    apr_size_t outcnt;
    char outbuf[LOG_BUFSIZE];
    apr_anylock_t mutex;
} buffered_log;

typedef struct {
    const char *fname;
    const char *format_string;
    apr_array_header_t *format;
    void *log_writer;
    char *condition_var;
} config_log_state;

/*
 * Format items...
 * Note that many of these could have ap_sprintfs replaced with static buffers.
 */

typedef struct {
    ap_log_handler_fn_t *func;
    char *arg;
    int condition_sense;
    int want_orig;
    apr_array_header_t *conditions;
} log_format_item;

static char *format_integer(apr_pool_t *p, int i)
{
    return apr_itoa(p, i);
}

static char *pfmt(apr_pool_t *p, int i)
{
    if (i <= 0) {
        return "-";
    }
    else {
        return format_integer(p, i);
    }
}

static const char *constant_item(request_rec *dummy, char *stuff)
{
    return stuff;
}

static const char *log_remote_host(request_rec *r, char *a)
{
    return ap_escape_logitem(r->pool, ap_get_remote_host(r->connection,
                                                         r->per_dir_config,
                                                         REMOTE_NAME, NULL));
}

static const char *log_remote_address(request_rec *r, char *a)
{
    return r->connection->remote_ip;
}

static const char *log_local_address(request_rec *r, char *a)
{
    return r->connection->local_ip;
}

static const char *log_remote_logname(request_rec *r, char *a)
{
    return ap_escape_logitem(r->pool, ap_get_remote_logname(r));
}

static const char *log_remote_user(request_rec *r, char *a)
{
    char *rvalue = r->user;

    if (rvalue == NULL) {
        rvalue = "-";
    }
    else if (strlen(rvalue) == 0) {
        rvalue = "\"\"";
    }
    else {
        rvalue = ap_escape_logitem(r->pool, rvalue);
    }

    return rvalue;
}

static const char *log_request_line(request_rec *r, char *a)
{
    /* NOTE: If the original request contained a password, we
     * re-write the request line here to contain XXXXXX instead:
     * (note the truncation before the protocol string for HTTP/0.9 requests)
     * (note also that r->the_request contains the unmodified request)
     */
    return ap_escape_logitem(r->pool,
                             (r->parsed_uri.password)
                               ? apr_pstrcat(r->pool, r->method, " ",
                                             apr_uri_unparse(r->pool,
                                                             &r->parsed_uri, 0),
                                             r->assbackwards ? NULL : " ",
                                             r->protocol, NULL)
                               : r->the_request);
}

static const char *log_request_file(request_rec *r, char *a)
{
    return ap_escape_logitem(r->pool, r->filename);
}
static const char *log_request_uri(request_rec *r, char *a)
{
    return ap_escape_logitem(r->pool, r->uri);