log.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。

                *e = '\0';
            }
            file = tmp;
        }
#endif /*_OSD_POSIX*/
        len += apr_snprintf(errstr + len, MAX_STRING_LEN - len,
                            "%s(%d): ", file, line);
    }
#endif /* TPF */

    if (r && r->connection) {
        /* XXX: TODO: add a method of selecting whether logged client
         * addresses are in dotted quad or resolved form... dotted
         * quad is the most secure, which is why I'm implementing it
         * first. -djg
         */
        len += apr_snprintf(errstr + len, MAX_STRING_LEN - len,
                            "[client %s] ", r->connection->remote_ip);
    }
    if (status != 0) {
        if (status < APR_OS_START_EAIERR) {
            len += apr_snprintf(errstr + len, MAX_STRING_LEN - len,
                                "(%d)", status);
        }
        else if (status < APR_OS_START_SYSERR) {
            len += apr_snprintf(errstr + len, MAX_STRING_LEN - len,
                                "(EAI %d)", status - APR_OS_START_EAIERR);
        }
        else if (status < 100000 + APR_OS_START_SYSERR) {
            len += apr_snprintf(errstr + len, MAX_STRING_LEN - len,
                                "(OS %d)", status - APR_OS_START_SYSERR);
        }
        else {
            len += apr_snprintf(errstr + len, MAX_STRING_LEN - len,
                                "(os 0x%08x)", status - APR_OS_START_SYSERR);
        }
        apr_strerror(status, errstr + len, MAX_STRING_LEN - len);
        len += strlen(errstr + len);
        if (MAX_STRING_LEN - len > 2) {
            errstr[len++] = ':';
            errstr[len++] = ' ';
            errstr[len] = '\0';
        }
    }

    errstrlen = len;
#ifndef AP_UNSAFE_ERROR_LOG_UNESCAPED
    if (apr_vsnprintf(scratch, MAX_STRING_LEN - len, fmt, args)) {
        len += ap_escape_errorlog_item(errstr + len, scratch,
                                       MAX_STRING_LEN - len);
    }
#else
    len += apr_vsnprintf(errstr + len, MAX_STRING_LEN - len, fmt, args);
#endif

    if (   r && (referer = apr_table_get(r->headers_in, "Referer"))
#ifndef AP_UNSAFE_ERROR_LOG_UNESCAPED
        && ap_escape_errorlog_item(scratch, referer, MAX_STRING_LEN - len)
#endif
        ) {
        len += apr_snprintf(errstr + len, MAX_STRING_LEN - len,
                            ", referer: %s",
#ifndef AP_UNSAFE_ERROR_LOG_UNESCAPED
                            scratch
#else
                            referer
#endif
                            );
    }

    /* NULL if we are logging to syslog */
    if (logf) {
        /* Truncate for the terminator (as apr_snprintf does) */
        if (len > MAX_STRING_LEN - sizeof(APR_EOL_STR)) {
            len = MAX_STRING_LEN - sizeof(APR_EOL_STR);
        }
        strcpy(errstr + len, APR_EOL_STR);
        apr_file_puts(errstr, logf);
        apr_file_flush(logf);
    }
#ifdef HAVE_SYSLOG
    else {
        syslog(level_and_mask, "%s", errstr);
    }
#endif

    ap_run_error_log(file, line, level, status, s, r, pool, errstr + errstrlen);
}

AP_DECLARE(void) ap_log_error(const char *file, int line, int level,
                              apr_status_t status, const server_rec *s,
                              const char *fmt, ...)
{
    va_list args;

    va_start(args, fmt);
    log_error_core(file, line, level, status, s, NULL, NULL, fmt, args);
    va_end(args);
}

AP_DECLARE(void) ap_log_perror(const char *file, int line, int level,
                               apr_status_t status, apr_pool_t *p,
                               const char *fmt, ...)
{
    va_list args;

    va_start(args, fmt);
    log_error_core(file, line, level, status, NULL, NULL, p, fmt, args);
    va_end(args);
}

AP_DECLARE(void) ap_log_rerror(const char *file, int line, int level,
                               apr_status_t status, const request_rec *r,
                               const char *fmt, ...)
{
    va_list args;

    va_start(args, fmt);
    log_error_core(file, line, level, status, r->server, r, NULL, fmt, args);

    /*
     * IF APLOG_TOCLIENT is set,
     * AND the error level is 'warning' or more severe,
     * AND there isn't already error text associated with this request,
     * THEN make the message text available to ErrorDocument and
     * other error processors.
     */
    va_end(args);
    va_start(args,fmt);
    if ((level & APLOG_TOCLIENT)
        && ((level & APLOG_LEVELMASK) <= APLOG_WARNING)
        && (apr_table_get(r->notes, "error-notes") == NULL)) {
        apr_table_setn(r->notes, "error-notes",
                       ap_escape_html(r->pool, apr_pvsprintf(r->pool, fmt,
                                                             args)));
    }
    va_end(args);
}

AP_DECLARE(void) ap_log_pid(apr_pool_t *p, const char *filename)
{
    apr_file_t *pid_file = NULL;
    apr_finfo_t finfo;
    static pid_t saved_pid = -1;
    pid_t mypid;
    apr_status_t rv;
    const char *fname;

    if (!filename) {
        return;
    }

    fname = ap_server_root_relative(p, filename);
    if (!fname) {
        ap_log_error(APLOG_MARK, APLOG_STARTUP|APLOG_CRIT, APR_EBADPATH, 
                     NULL, "Invalid PID file path %s, ignoring.", filename);
        return;
    }

    mypid = getpid();
    if (mypid != saved_pid
        && apr_stat(&finfo, fname, APR_FINFO_MTIME, p) == APR_SUCCESS) {
        /* AP_SIG_GRACEFUL and HUP call this on each restart.
         * Only warn on first time through for this pid.
         *
         * XXX: Could just write first time through too, although
         *      that may screw up scripts written to do something
         *      based on the last modification time of the pid file.
         */
        ap_log_perror(APLOG_MARK, APLOG_WARNING, 0, p,
                      apr_psprintf(p, "pid file %s overwritten -- Unclean "
                                   "shutdown of previous Apache run?",
                                   fname));
    }

    if ((rv = apr_file_open(&pid_file, fname,
                            APR_WRITE | APR_CREATE | APR_TRUNCATE,
                            APR_UREAD | APR_UWRITE | APR_GREAD | APR_WREAD, p))
        != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_ERR, rv, NULL,
                     "could not create %s", fname);
        ap_log_error(APLOG_MARK, APLOG_ERR, 0, NULL,
                     "%s: could not log pid to file %s",
                     ap_server_argv0, fname);
        exit(1);
    }
    apr_file_printf(pid_file, "%ld" APR_EOL_STR, (long)mypid);
    apr_file_close(pid_file);
    saved_pid = mypid;
}

AP_DECLARE(apr_status_t) ap_read_pid(apr_pool_t *p, const char *filename,
                                     pid_t *mypid)
{
    const apr_size_t BUFFER_SIZE = sizeof(long) * 3 + 2; /* see apr_ltoa */
    apr_file_t *pid_file = NULL;
    apr_status_t rv;
    const char *fname;
    char *buf, *endptr;
    apr_size_t bytes_read;

    if (!filename) {
        return APR_EGENERAL;
    }

    fname = ap_server_root_relative(p, filename);
    if (!fname) {
        ap_log_error(APLOG_MARK, APLOG_STARTUP|APLOG_CRIT, APR_EBADPATH, 
                     NULL, "Invalid PID file path %s, ignoring.", filename);
        return APR_EGENERAL;
    }

    rv = apr_file_open(&pid_file, fname, APR_READ, APR_OS_DEFAULT, p);
    if (rv != APR_SUCCESS) {
        return rv;
    }

    /* Ensure null-termination, so that strtol doesn't go crazy. */
    buf = apr_palloc(p, BUFFER_SIZE);
    buf[BUFFER_SIZE - 1] = '\0';

    rv = apr_file_read_full(pid_file, buf, BUFFER_SIZE - 1, &bytes_read);
    if (rv != APR_SUCCESS && rv != APR_EOF) {
        return rv;
    }

    /* If we fill the buffer, we're probably reading a corrupt pid file.
     * To be nice, let's also ensure the first char is a digit. */
    if (bytes_read == BUFFER_SIZE - 1 || !apr_isdigit(*buf)) {
        return APR_EGENERAL;
    }

    *mypid = strtol(buf, &endptr, 10);

    apr_file_close(pid_file);
    return APR_SUCCESS;
}

AP_DECLARE(void) ap_log_assert(const char *szExp, const char *szFile,
                               int nLine)
{
    char time_str[APR_CTIME_LEN];

    apr_ctime(time_str, apr_time_now());
    ap_log_error(APLOG_MARK, APLOG_CRIT, 0, NULL,
                 "[%s] file %s, line %d, assertion \"%s\" failed",
                 time_str, szFile, nLine, szExp);
#if defined(WIN32)
    DebugBreak();
#else
    /* unix assert does an abort leading to a core dump */
    abort();
#endif
}

/* piped log support */

#ifdef AP_HAVE_RELIABLE_PIPED_LOGS
/* forward declaration */
static void piped_log_maintenance(int reason, void *data, apr_wait_t status);

static int piped_log_spawn(piped_log *pl)
{
    int rc = 0;
    apr_procattr_t *procattr;
    apr_proc_t *procnew = NULL;
    apr_status_t status;

    if (((status = apr_procattr_create(&procattr, pl->p)) != APR_SUCCESS) ||
        ((status = apr_procattr_child_in_set(procattr,
                                             ap_piped_log_read_fd(pl),
                                             ap_piped_log_write_fd(pl)))
        != APR_SUCCESS) ||
        ((status = apr_procattr_child_errfn_set(procattr, log_child_errfn))
         != APR_SUCCESS) ||
        ((status = apr_procattr_error_check_set(procattr, 1)) != APR_SUCCESS)) {
        char buf[120];
        /* Something bad happened, give up and go away. */
        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                     "piped_log_spawn: unable to setup child process '%s': %s",
                     pl->program, apr_strerror(status, buf, sizeof(buf)));
        rc = -1;
    }
    else {
        char **args;
        const char *pname;

        apr_tokenize_to_argv(pl->program, &args, pl->p);
        pname = apr_pstrdup(pl->p, args[0]);
        procnew = apr_pcalloc(pl->p, sizeof(apr_proc_t));
        status = apr_proc_create(procnew, pname, (const char * const *) args,
                                 NULL, procattr, pl->p);

        if (status == APR_SUCCESS) {
            pl->pid = procnew;
            ap_piped_log_write_fd(pl) = procnew->in;
            apr_proc_other_child_register(procnew, piped_log_maintenance, pl,
                                          ap_piped_log_write_fd(pl), pl->p);
        }
        else {
            char buf[120];
            /* Something bad happened, give up and go away. */
            ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                         "unable to start piped log program '%s': %s",
                         pl->program, apr_strerror(status, buf, sizeof(buf)));
            rc = -1;
        }
    }

    return rc;
}


static void piped_log_maintenance(int reason, void *data, apr_wait_t status)
{
    piped_log *pl = data;
    apr_status_t stats;
    int mpm_state;

    switch (reason) {
    case APR_OC_REASON_DEATH:
    case APR_OC_REASON_LOST:
        pl->pid = NULL; /* in case we don't get it going again, this
                         * tells other logic not to try to kill it
                         */
        apr_proc_other_child_unregister(pl);
        stats = ap_mpm_query(AP_MPMQ_MPM_STATE, &mpm_state);
        if (stats != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                         "can't query MPM state; not restarting "
                         "piped log program '%s'",
                         pl->program);
        }
        else if (mpm_state != AP_MPMQ_STOPPING) {
            ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                         "piped log program '%s' failed unexpectedly",
                         pl->program);
            if ((stats = piped_log_spawn(pl)) != APR_SUCCESS) {
                /* what can we do?  This could be the error log we're having
                 * problems opening up... */
                char buf[120];
                ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                             "piped_log_maintenance: unable to respawn '%s': %s",
                             pl->program, apr_strerror(stats, buf, sizeof(buf)));
            }
        }
        break;

    case APR_OC_REASON_UNWRITABLE:
        /* We should not kill off the pipe here, since it may only be full.
         * If it really is locked, we should kill it off manually. */
    break;

    case APR_OC_REASON_RESTART:
        if (pl->pid != NULL) {
            apr_proc_kill(pl->pid, SIGTERM);
            pl->pid = NULL;
        }
        break;

    case APR_OC_REASON_UNREGISTER:
        break;
    }
}


static apr_status_t piped_log_cleanup_for_exec(void *data)
{
    piped_log *pl = data;

    apr_file_close(ap_piped_log_read_fd(pl));
    apr_file_close(ap_piped_log_write_fd(pl));
    return APR_SUCCESS;
}


static apr_status_t piped_log_cleanup(void *data)
{
    piped_log *pl = data;

    if (pl->pid != NULL) {
        apr_proc_kill(pl->pid, SIGTERM);
    }
    return piped_log_cleanup_for_exec(data);
}


AP_DECLARE(piped_log *) ap_open_piped_log(apr_pool_t *p, const char *program)
{
    piped_log *pl;

    pl = apr_palloc(p, sizeof (*pl));
    pl->p = p;
    pl->program = apr_pstrdup(p, program);
    pl->pid = NULL;
    if (apr_file_pipe_create(&ap_piped_log_read_fd(pl),
                             &ap_piped_log_write_fd(pl), p) != APR_SUCCESS) {
        return NULL;
    }
    apr_pool_cleanup_register(p, pl, piped_log_cleanup,
                              piped_log_cleanup_for_exec);
    if (piped_log_spawn(pl) == -1) {
        int save_errno = errno;
        apr_pool_cleanup_kill(p, pl, piped_log_cleanup);
        apr_file_close(ap_piped_log_read_fd(pl));
        apr_file_close(ap_piped_log_write_fd(pl));
        errno = save_errno;
        return NULL;
    }
    return pl;
}

#else /* !AP_HAVE_RELIABLE_PIPED_LOGS */

static apr_status_t piped_log_cleanup(void *data)
{
    piped_log *pl = data;

    apr_file_close(ap_piped_log_write_fd(pl));
    return APR_SUCCESS;
}

AP_DECLARE(piped_log *) ap_open_piped_log(apr_pool_t *p, const char *program)
{
    piped_log *pl;
    apr_file_t *dummy = NULL;
    int rc;

    rc = log_child(p, program, &dummy);
    if (rc != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_STARTUP, rc, NULL,
                     "Couldn't start piped log process");
        return NULL;
    }

    pl = apr_palloc(p, sizeof (*pl));
    pl->p = p;
    ap_piped_log_read_fd(pl) = NULL;
    ap_piped_log_write_fd(pl) = dummy;
    apr_pool_cleanup_register(p, pl, piped_log_cleanup, piped_log_cleanup);

    return pl;
}

#endif

AP_DECLARE(void) ap_close_piped_log(piped_log *pl)
{
    apr_pool_cleanup_run(pl->p, pl, piped_log_cleanup);
}

AP_IMPLEMENT_HOOK_VOID(error_log,
                       (const char *file, int line, int level,
                        apr_status_t status, const server_rec *s,
                        const request_rec *r, apr_pool_t *pool,
                        const char *errstr), (file, line, level,
                        status, s, r, pool, errstr))