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。

/* 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.
 */

/*
 * http_log.c: Dealing with the logs and errors
 *
 * Rob McCool
 *
 */

#include "apr.h"
#include "apr_general.h"        /* for signal stuff */
#include "apr_strings.h"
#include "apr_errno.h"
#include "apr_thread_proc.h"
#include "apr_lib.h"
#include "apr_signal.h"

#define APR_WANT_STDIO
#define APR_WANT_STRFUNC
#include "apr_want.h"

#if APR_HAVE_STDARG_H
#include <stdarg.h>
#endif
#if APR_HAVE_UNISTD_H
#include <unistd.h>
#endif

#define CORE_PRIVATE

#include "ap_config.h"
#include "httpd.h"
#include "http_config.h"
#include "http_core.h"
#include "http_log.h"
#include "http_main.h"
#include "util_time.h"
#include "ap_mpm.h"

#ifndef APR_LARGEFILE
#define APR_LARGEFILE 0
#endif

typedef struct {
    char    *t_name;
    int      t_val;
} TRANS;

APR_HOOK_STRUCT(
    APR_HOOK_LINK(error_log)
)

int AP_DECLARE_DATA ap_default_loglevel = DEFAULT_LOGLEVEL;

#ifdef HAVE_SYSLOG

static const TRANS facilities[] = {
    {"auth",    LOG_AUTH},
#ifdef LOG_AUTHPRIV
    {"authpriv",LOG_AUTHPRIV},
#endif
#ifdef LOG_CRON
    {"cron",    LOG_CRON},
#endif
#ifdef LOG_DAEMON
    {"daemon",  LOG_DAEMON},
#endif
#ifdef LOG_FTP
    {"ftp", LOG_FTP},
#endif
#ifdef LOG_KERN
    {"kern",    LOG_KERN},
#endif
#ifdef LOG_LPR
    {"lpr", LOG_LPR},
#endif
#ifdef LOG_MAIL
    {"mail",    LOG_MAIL},
#endif
#ifdef LOG_NEWS
    {"news",    LOG_NEWS},
#endif
#ifdef LOG_SYSLOG
    {"syslog",  LOG_SYSLOG},
#endif
#ifdef LOG_USER
    {"user",    LOG_USER},
#endif
#ifdef LOG_UUCP
    {"uucp",    LOG_UUCP},
#endif
#ifdef LOG_LOCAL0
    {"local0",  LOG_LOCAL0},
#endif
#ifdef LOG_LOCAL1
    {"local1",  LOG_LOCAL1},
#endif
#ifdef LOG_LOCAL2
    {"local2",  LOG_LOCAL2},
#endif
#ifdef LOG_LOCAL3
    {"local3",  LOG_LOCAL3},
#endif
#ifdef LOG_LOCAL4
    {"local4",  LOG_LOCAL4},
#endif
#ifdef LOG_LOCAL5
    {"local5",  LOG_LOCAL5},
#endif
#ifdef LOG_LOCAL6
    {"local6",  LOG_LOCAL6},
#endif
#ifdef LOG_LOCAL7
    {"local7",  LOG_LOCAL7},
#endif
    {NULL,      -1},
};
#endif

static const TRANS priorities[] = {
    {"emerg",   APLOG_EMERG},
    {"alert",   APLOG_ALERT},
    {"crit",    APLOG_CRIT},
    {"error",   APLOG_ERR},
    {"warn",    APLOG_WARNING},
    {"notice",  APLOG_NOTICE},
    {"info",    APLOG_INFO},
    {"debug",   APLOG_DEBUG},
    {NULL,      -1},
};

static apr_file_t *stderr_log = NULL;

AP_DECLARE(void) ap_open_stderr_log(apr_pool_t *p)
{
    apr_file_open_stderr(&stderr_log, p);
}

AP_DECLARE(apr_status_t) ap_replace_stderr_log(apr_pool_t *p, 
                                               const char *fname)
{
    apr_file_t *stderr_file;
    apr_status_t rc;
    char *filename = ap_server_root_relative(p, fname);
    if (!filename) {
        ap_log_error(APLOG_MARK, APLOG_STARTUP|APLOG_CRIT,
                     APR_EBADPATH, NULL, "Invalid -E error log file %s",
                     fname);
        return APR_EBADPATH;
    }
    if ((rc = apr_file_open(&stderr_file, filename,
                            APR_APPEND | APR_WRITE | APR_CREATE | APR_LARGEFILE,
                            APR_OS_DEFAULT, p)) != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_STARTUP, rc, NULL,
                     "%s: could not open error log file %s.",
                     ap_server_argv0, fname);
        return rc;
    }
    if ((rc = apr_file_open_stderr(&stderr_log, p)) == APR_SUCCESS) {
        apr_file_flush(stderr_log);
        if ((rc = apr_file_dup2(stderr_log, stderr_file, p)) == APR_SUCCESS) {
            apr_file_close(stderr_file);
        }
    }
    if (rc != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, rc, NULL,
                     "unable to replace stderr with error_log");
    }
    return rc;
}

static void log_child_errfn(apr_pool_t *pool, apr_status_t err,
                            const char *description)
{
    ap_log_error(APLOG_MARK, APLOG_ERR, err, NULL,
                 "%s", description);
}

static int log_child(apr_pool_t *p, const char *progname,
                     apr_file_t **fpin)
{
    /* Child process code for 'ErrorLog "|..."';
     * may want a common framework for this, since I expect it will
     * be common for other foo-loggers to want this sort of thing...
     */
    apr_status_t rc;
    apr_procattr_t *procattr;
    apr_proc_t *procnew;

    if (((rc = apr_procattr_create(&procattr, p)) == APR_SUCCESS)
        && ((rc = apr_procattr_io_set(procattr,
                                      APR_FULL_BLOCK,
                                      APR_NO_PIPE,
                                      APR_NO_PIPE)) == APR_SUCCESS)
        && ((rc = apr_procattr_error_check_set(procattr, 1)) == APR_SUCCESS)
        && ((rc = apr_procattr_child_errfn_set(procattr, log_child_errfn)) == APR_SUCCESS)) {
        char **args;
        const char *pname;

        apr_tokenize_to_argv(progname, &args, p);
        pname = apr_pstrdup(p, args[0]);
        procnew = (apr_proc_t *)apr_pcalloc(p, sizeof(*procnew));
        rc = apr_proc_create(procnew, pname, (const char * const *)args,
                             NULL, procattr, p);

        if (rc == APR_SUCCESS) {
            apr_pool_note_subprocess(p, procnew, APR_KILL_AFTER_TIMEOUT);
            (*fpin) = procnew->in;
        }
    }

    return rc;
}

static int open_error_log(server_rec *s, apr_pool_t *p)
{
    const char *fname;
    int rc;

    if (*s->error_fname == '|') {
        apr_file_t *dummy = NULL;

        /* This starts a new process... */
        rc = log_child (p, s->error_fname + 1, &dummy);
        if (rc != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_STARTUP, rc, NULL,
                         "Couldn't start ErrorLog process");
            return DONE;
        }

        s->error_log = dummy;
    }

#ifdef HAVE_SYSLOG
    else if (!strncasecmp(s->error_fname, "syslog", 6)) {
        if ((fname = strchr(s->error_fname, ':'))) {
            const TRANS *fac;

            fname++;
            for (fac = facilities; fac->t_name; fac++) {
                if (!strcasecmp(fname, fac->t_name)) {
                    openlog(ap_server_argv0, LOG_NDELAY|LOG_CONS|LOG_PID,
                            fac->t_val);
                    s->error_log = NULL;
                    return OK;
                }
            }
        }
        else {
            openlog(ap_server_argv0, LOG_NDELAY|LOG_CONS|LOG_PID, LOG_LOCAL7);
        }

        s->error_log = NULL;
    }
#endif
    else {
        fname = ap_server_root_relative(p, s->error_fname);
        if (!fname) {
            ap_log_error(APLOG_MARK, APLOG_STARTUP, APR_EBADPATH, NULL,
                         "%s: Invalid error log path %s.",
                         ap_server_argv0, s->error_fname);
            return DONE;
        }
        if ((rc = apr_file_open(&s->error_log, fname,
                               APR_APPEND | APR_WRITE | APR_CREATE | APR_LARGEFILE,
                               APR_OS_DEFAULT, p)) != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_STARTUP, rc, NULL,
                         "%s: could not open error log file %s.",
                         ap_server_argv0, fname);
            return DONE;
        }
    }

    return OK;
}

int ap_open_logs(apr_pool_t *pconf, apr_pool_t *p /* plog */, 
                 apr_pool_t *ptemp, server_rec *s_main)
{
    apr_status_t rc = APR_SUCCESS;
    server_rec *virt, *q;
    int replace_stderr;
    apr_file_t *errfile = NULL;

    if (open_error_log(s_main, p) != OK) {
        return DONE;
    }

    replace_stderr = 1;
    if (s_main->error_log) {
        /* replace stderr with this new log */
        apr_file_flush(s_main->error_log);
        if ((rc = apr_file_open_stderr(&errfile, p)) == APR_SUCCESS) {
            rc = apr_file_dup2(errfile, s_main->error_log, p);
        }
        if (rc != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_CRIT, rc, s_main,
                         "unable to replace stderr with error_log");
        }
        else {
            replace_stderr = 0;
        }
    }
    /* note that stderr may still need to be replaced with something
     * because it points to the old error log, or back to the tty
     * of the submitter.
     * XXX: This is BS - /dev/null is non-portable
     */
    if (replace_stderr && freopen("/dev/null", "w", stderr) == NULL) {
        ap_log_error(APLOG_MARK, APLOG_CRIT, errno, s_main,
                     "unable to replace stderr with /dev/null");
    }

    for (virt = s_main->next; virt; virt = virt->next) {
        if (virt->error_fname) {
            for (q=s_main; q != virt; q = q->next) {
                if (q->error_fname != NULL
                    && strcmp(q->error_fname, virt->error_fname) == 0) {
                    break;
                }
            }

            if (q == virt) {
                if (open_error_log(virt, p) != OK) {
                    return DONE;
                }
            }
            else {
                virt->error_log = q->error_log;
            }
        }
        else {
            virt->error_log = s_main->error_log;
        }
    }
    return OK;
}

AP_DECLARE(void) ap_error_log2stderr(server_rec *s) {
    apr_file_t *errfile = NULL;

    apr_file_open_stderr(&errfile, s->process->pool);
    if (s->error_log != NULL) {
        apr_file_dup2(s->error_log, errfile, s->process->pool);
    }
}

static void log_error_core(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 *fmt, va_list args)
{
    char errstr[MAX_STRING_LEN];
#ifndef AP_UNSAFE_ERROR_LOG_UNESCAPED
    char scratch[MAX_STRING_LEN];
#endif
    apr_size_t len, errstrlen;
    apr_file_t *logf = NULL;
    const char *referer;
    int level_and_mask = level & APLOG_LEVELMASK;

    if (s == NULL) {
        /*
         * If we are doing stderr logging (startup), don't log messages that are
         * above the default server log level unless it is a startup/shutdown
         * notice
         */
        if ((level_and_mask != APLOG_NOTICE)
            && (level_and_mask > ap_default_loglevel)) {
            return;
        }

        logf = stderr_log;
    }
    else if (s->error_log) {
        /*
         * If we are doing normal logging, don't log messages that are
         * above the server log level unless it is a startup/shutdown notice
         */
        if ((level_and_mask != APLOG_NOTICE)
            && (level_and_mask > s->loglevel)) {
            return;
        }

        logf = s->error_log;
    }
#ifdef TPF
    else if (tpf_child) {
        /*
         * If we are doing normal logging, don't log messages that are
         * above the server log level unless it is a startup/shutdown notice
         */
        if ((level_and_mask != APLOG_NOTICE)
            && (level_and_mask > s->loglevel)) {
            return;
        }

        logf = stderr;
    }
#endif /* TPF */
    else {
        /*
         * If we are doing syslog logging, don't log messages that are
         * above the server log level (including a startup/shutdown notice)
         */
        if (level_and_mask > s->loglevel) {
            return;
        }
    }

    if (logf && ((level & APLOG_STARTUP) != APLOG_STARTUP)) {
        errstr[0] = '[';
        ap_recent_ctime(errstr + 1, apr_time_now());
        errstr[1 + APR_CTIME_LEN - 1] = ']';
        errstr[1 + APR_CTIME_LEN    ] = ' ';
        len = 1 + APR_CTIME_LEN + 1;
    } else {
        len = 0;
    }

    if ((level & APLOG_STARTUP) != APLOG_STARTUP) {
        len += apr_snprintf(errstr + len, MAX_STRING_LEN - len,
                            "[%s] ", priorities[level_and_mask].t_name);
    }

#ifndef TPF
    if (file && level_and_mask == APLOG_DEBUG) {
#if defined(_OSD_POSIX) || defined(WIN32)
        char tmp[256];
        char *e = strrchr(file, '/');
#ifdef WIN32
        if (!e) {
            e = strrchr(file, '\\');
        }
#endif

        /* In OSD/POSIX, the compiler returns for __FILE__
         * a string like: __FILE__="*POSIX(/usr/include/stdio.h)"
         * (it even returns an absolute path for sources in
         * the current directory). Here we try to strip this
         * down to the basename.
         */
        if (e != NULL && e[1] != '\0') {
            apr_snprintf(tmp, sizeof(tmp), "%s", &e[1]);
            e = &tmp[strlen(tmp)-1];
            if (*e == ')') {