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。

}
static const char *log_request_method(request_rec *r, char *a)
{
    return ap_escape_logitem(r->pool, r->method);
}
static const char *log_request_protocol(request_rec *r, char *a)
{
    return ap_escape_logitem(r->pool, r->protocol);
}
static const char *log_request_query(request_rec *r, char *a)
{
    return (r->args) ? apr_pstrcat(r->pool, "?",
                                   ap_escape_logitem(r->pool, r->args), NULL)
                     : "";
}
static const char *log_status(request_rec *r, char *a)
{
    return pfmt(r->pool, r->status);
}

static const char *clf_log_bytes_sent(request_rec *r, char *a)
{
    if (!r->sent_bodyct || !r->bytes_sent) {
        return "-";
    }
    else {
        return apr_off_t_toa(r->pool, r->bytes_sent);
    }
}

static const char *log_bytes_sent(request_rec *r, char *a)
{
    if (!r->sent_bodyct || !r->bytes_sent) {
        return "0";
    }
    else {
        return apr_psprintf(r->pool, "%" APR_OFF_T_FMT, r->bytes_sent);
    }
}


static const char *log_header_in(request_rec *r, char *a)
{
    return ap_escape_logitem(r->pool, apr_table_get(r->headers_in, a));
}

static const char *log_header_out(request_rec *r, char *a)
{
    const char *cp = apr_table_get(r->headers_out, a);
    if (!strcasecmp(a, "Content-type") && r->content_type) {
        cp = ap_field_noparam(r->pool, r->content_type);
    }
    if (cp) {
        return ap_escape_logitem(r->pool, cp);
    }
    return ap_escape_logitem(r->pool, apr_table_get(r->err_headers_out, a));
}

static const char *log_note(request_rec *r, char *a)
{
    return ap_escape_logitem(r->pool, apr_table_get(r->notes, a));
}
static const char *log_env_var(request_rec *r, char *a)
{
    return ap_escape_logitem(r->pool, apr_table_get(r->subprocess_env, a));
}

static const char *log_cookie(request_rec *r, char *a)
{
    const char *cookies;
    const char *start_cookie;

    if ((cookies = apr_table_get(r->headers_in, "Cookie"))) {
        if ((start_cookie = ap_strstr_c(cookies,a))) {
            char *cookie, *end_cookie;
            start_cookie += strlen(a) + 1; /* cookie_name + '=' */
            cookie = apr_pstrdup(r->pool, start_cookie);
            /* kill everything in cookie after ';' */
            end_cookie = strchr(cookie, ';'); 
            if (end_cookie) {
                *end_cookie = '\0';
            }
            return ap_escape_logitem(r->pool, cookie);
        }
    }
    return NULL;
}

static const char *log_request_time_custom(request_rec *r, char *a,
                                           apr_time_exp_t *xt)
{
    apr_size_t retcode;
    char tstr[MAX_STRING_LEN];
    apr_strftime(tstr, &retcode, sizeof(tstr), a, xt);
    return apr_pstrdup(r->pool, tstr);
}

#define DEFAULT_REQUEST_TIME_SIZE 32
typedef struct {
    unsigned t;
    char timestr[DEFAULT_REQUEST_TIME_SIZE];
    unsigned t_validate;
} cached_request_time;

#define TIME_CACHE_SIZE 4
#define TIME_CACHE_MASK 3
static cached_request_time request_time_cache[TIME_CACHE_SIZE];

static const char *log_request_time(request_rec *r, char *a)
{
    apr_time_exp_t xt;

    /* ###  I think getting the time again at the end of the request
     * just for logging is dumb.  i know it's "required" for CLF.
     * folks writing log parsing tools don't realise that out of order
     * times have always been possible (consider what happens if one
     * process calculates the time to log, but then there's a context
     * switch before it writes and before that process is run again the
     * log rotation occurs) and they should just fix their tools rather
     * than force the server to pay extra cpu cycles.  if you've got
     * a problem with this, you can set the define.  -djg
     */
    if (a && *a) {              /* Custom format */
        /* The custom time formatting uses a very large temp buffer
         * on the stack.  To avoid using so much stack space in the
         * common case where we're not using a custom format, the code
         * for the custom format in a separate function.  (That's why
         * log_request_time_custom is not inlined right here.)
         */
#ifdef I_INSIST_ON_EXTRA_CYCLES_FOR_CLF_COMPLIANCE
        ap_explode_recent_localtime(&xt, apr_time_now());
#else
        ap_explode_recent_localtime(&xt, r->request_time);
#endif
        return log_request_time_custom(r, a, &xt);
    }
    else {                      /* CLF format */
        /* This code uses the same technique as ap_explode_recent_localtime():
         * optimistic caching with logic to detect and correct race conditions.
         * See the comments in server/util_time.c for more information.
         */
        cached_request_time* cached_time = apr_palloc(r->pool,
                                                      sizeof(*cached_time));
#ifdef I_INSIST_ON_EXTRA_CYCLES_FOR_CLF_COMPLIANCE
        apr_time_t request_time = apr_time_now();
#else
        apr_time_t request_time = r->request_time;
#endif
        unsigned t_seconds = (unsigned)apr_time_sec(request_time);
        unsigned i = t_seconds & TIME_CACHE_MASK;
        memcpy(cached_time, &(request_time_cache[i]), sizeof(*cached_time));
        if ((t_seconds != cached_time->t) ||
            (t_seconds != cached_time->t_validate)) {

            /* Invalid or old snapshot, so compute the proper time string
             * and store it in the cache
             */
            char sign;
            int timz;

            ap_explode_recent_localtime(&xt, request_time);
            timz = xt.tm_gmtoff;
            if (timz < 0) {
                timz = -timz;
                sign = '-';
            }
            else {
                sign = '+';
            }
            cached_time->t = t_seconds;
            apr_snprintf(cached_time->timestr, DEFAULT_REQUEST_TIME_SIZE,
                         "[%02d/%s/%d:%02d:%02d:%02d %c%.2d%.2d]",
                         xt.tm_mday, apr_month_snames[xt.tm_mon],
                         xt.tm_year+1900, xt.tm_hour, xt.tm_min, xt.tm_sec,
                         sign, timz / (60*60), (timz % (60*60)) / 60);
            cached_time->t_validate = t_seconds;
            memcpy(&(request_time_cache[i]), cached_time,
                   sizeof(*cached_time));
        }
        return cached_time->timestr;
    }
}

static const char *log_request_duration(request_rec *r, char *a)
{
    apr_time_t duration = apr_time_now() - r->request_time;
    return apr_psprintf(r->pool, "%" APR_TIME_T_FMT, apr_time_sec(duration));
}

static const char *log_request_duration_microseconds(request_rec *r, char *a)
{
    return apr_psprintf(r->pool, "%" APR_TIME_T_FMT, 
                        (apr_time_now() - r->request_time));
}

/* These next two routines use the canonical name:port so that log
 * parsers don't need to duplicate all the vhost parsing crud.
 */
static const char *log_virtual_host(request_rec *r, char *a)
{
    return ap_escape_logitem(r->pool, r->server->server_hostname);
}

static const char *log_server_port(request_rec *r, char *a)
{
    return apr_psprintf(r->pool, "%u",
                        r->server->port ? r->server->port : ap_default_port(r));
}

/* This respects the setting of UseCanonicalName so that
 * the dynamic mass virtual hosting trick works better.
 */
static const char *log_server_name(request_rec *r, char *a)
{
    return ap_escape_logitem(r->pool, ap_get_server_name(r));
}

static const char *log_pid_tid(request_rec *r, char *a)
{
    if (*a == '\0' || !strcmp(a, "pid")) {
        return apr_psprintf(r->pool, "%" APR_PID_T_FMT, getpid());
    }
    else if (!strcmp(a, "tid")) {
#if APR_HAS_THREADS
        apr_os_thread_t tid = apr_os_thread_current();
#else
        int tid = 0; /* APR will format "0" anyway but an arg is needed */
#endif
        return apr_psprintf(r->pool, "%pT", &tid);
    }
    /* bogus format */
    return a;
}

static const char *log_connection_status(request_rec *r, char *a)
{
    if (r->connection->aborted)
        return "X";

    if (r->connection->keepalive == AP_CONN_KEEPALIVE && 
        (!r->server->keep_alive_max ||
         (r->server->keep_alive_max - r->connection->keepalives) > 0)) {
        return "+";
    }
    return "-";
}

/*****************************************************************
 *
 * Parsing the log format string
 */

static char *parse_log_misc_string(apr_pool_t *p, log_format_item *it,
                                   const char **sa)
{
    const char *s;
    char *d;

    it->func = constant_item;
    it->conditions = NULL;

    s = *sa;
    while (*s && *s != '%') {
        s++;
    }
    /*
     * This might allocate a few chars extra if there's a backslash
     * escape in the format string.
     */
    it->arg = apr_palloc(p, s - *sa + 1);

    d = it->arg;
    s = *sa;
    while (*s && *s != '%') {
        if (*s != '\\') {
            *d++ = *s++;
        }
        else {
            s++;
            switch (*s) {
            case '\\':
                *d++ = '\\';
                s++;
                break;
            case 'r':
                *d++ = '\r';
                s++;
                break;
            case 'n':
                *d++ = '\n';
                s++;
                break;
            case 't':
                *d++ = '\t';
                s++;
                break;
            default:
                /* copy verbatim */
                *d++ = '\\';
                /*
                 * Allow the loop to deal with this *s in the normal
                 * fashion so that it handles end of string etc.
                 * properly.
                 */
                break;
            }
        }
    }
    *d = '\0';

    *sa = s;
    return NULL;
}

static char *parse_log_item(apr_pool_t *p, log_format_item *it, const char **sa)
{
    const char *s = *sa;
    ap_log_handler *handler;

    if (*s != '%') {
        return parse_log_misc_string(p, it, sa);
    }

    ++s;
    it->condition_sense = 0;
    it->conditions = NULL;

    if (*s == '%') {
        it->arg = "%";
        it->func = constant_item;
        *sa = ++s;
    
        return NULL;
    }

    it->want_orig = -1;
    it->arg = "";               /* For safety's sake... */

    while (*s) {
        int i;

        switch (*s) {
        case '!':
            ++s;
            it->condition_sense = !it->condition_sense;
            break;

        case '<':
            ++s;
            it->want_orig = 1;
            break;

        case '>':
            ++s;
            it->want_orig = 0;
            break;

        case ',':
            ++s;
            break;

        case '{':
            ++s;