/* Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You 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"

#include "apr_portable.h"

#include "apr_base64.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

#if APR_HAVE_PROCESS_H

#include <process.h>            /* for getpid() on Win32 */

#endif

#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"

#include "ap_listen.h"

#if HAVE_GETTID

#include <sys/syscall.h>

#include <sys/types.h>

#endif

/* we know core's module_index is 0 */

#undef APLOG_MODULE_INDEX

#define APLOG_MODULE_INDEX AP_CORE_MODULE_INDEX

typedef struct {

    const char *t_name;

    int t_val;

} TRANS;

APR_HOOK_STRUCT(

    APR_HOOK_LINK(error_log)

    APR_HOOK_LINK(generate_log_id)

)

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},

    {"trace1",  APLOG_TRACE1},

    {"trace2",  APLOG_TRACE2},

    {"trace3",  APLOG_TRACE3},

    {"trace4",  APLOG_TRACE4},

    {"trace5",  APLOG_TRACE5},

    {"trace6",  APLOG_TRACE6},

    {"trace7",  APLOG_TRACE7},

    {"trace8",  APLOG_TRACE8},

    {NULL,      -1},

};

static apr_pool_t *stderr_pool = NULL;

static apr_file_t *stderr_log = NULL;

/* track pipe handles to close in child process */

typedef struct read_handle_t {

    struct read_handle_t *next;

    apr_file_t *handle;

} read_handle_t;

static read_handle_t *read_handles;

/**

 * @brief The piped logging structure.

 *

 * Piped logs are used to move functionality out of the main server.

 * For example, log rotation is done with piped logs.

 */

struct piped_log {

    /** The pool to use for the piped log */

    apr_pool_t *p;

    /** The pipe between the server and the logging process */

    apr_file_t *read_fd, *write_fd;

#ifdef AP_HAVE_RELIABLE_PIPED_LOGS

    /** The name of the program the logging process is running */

    char *program;

    /** The pid of the logging process */

    apr_proc_t *pid;

    /** How to reinvoke program when it must be replaced */

    apr_cmdtype_e cmdtype;

#endif

};

AP_DECLARE(apr_file_t *) ap_piped_log_read_fd(piped_log *pl)

{

    return pl->read_fd;

}

AP_DECLARE(apr_file_t *) ap_piped_log_write_fd(piped_log *pl)

{

    return pl->write_fd;

}

/* remember to close this handle in the child process

 *

 * On Win32 this makes zero sense, because we don't

 * take the parent process's child procs.

 * If the win32 parent instead passed each and every

 * logger write handle from itself down to the child,

 * and the parent manages all aspects of keeping the

 * reliable pipe log children alive, this would still

 * make no sense :)  Cripple it on Win32.

 */

static void close_handle_in_child(apr_pool_t *p, apr_file_t *f)

{

#ifndef WIN32

    read_handle_t *new_handle;

    new_handle = apr_pcalloc(p, sizeof(read_handle_t));

    new_handle->next = read_handles;

    new_handle->handle = f;

    read_handles = new_handle;

#endif

}

void ap_logs_child_init(apr_pool_t *p, server_rec *s)

{

    read_handle_t *cur = read_handles;

    while (cur) {

        apr_file_close(cur->handle);

        cur = cur->next;

    }

}

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, ap_server_conf, APLOGNO(00085) "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, ap_server_conf, APLOGNO(00086)

                     "%s: could not open error log file %s.",

                     ap_server_argv0, fname);

        return rc;

    }

    if (!stderr_pool) {

        /* This is safe provided we revert it when we are finished.

         * We don't manager the callers pool!

         */

        stderr_pool = p;

    }

    if ((rc = apr_file_open_stderr(&stderr_log, stderr_pool))

            == APR_SUCCESS) {

        apr_file_flush(stderr_log);

        if ((rc = apr_file_dup2(stderr_log, stderr_file, stderr_pool))

                == APR_SUCCESS) {

            apr_file_close(stderr_file);

            /*

             * You might ponder why stderr_pool should survive?

             * The trouble is, stderr_pool may have s_main->error_log,

             * so we aren't in a position to destory stderr_pool until

             * the next recycle.  There's also an apparent bug which

             * is not; if some folk decided to call this function before

             * the core open error logs hook, this pool won't survive.

             * Neither does the stderr logger, so this isn't a problem.

             */

        }

    }

    /* Revert, see above */

    if (stderr_pool == p)

        stderr_pool = NULL;

    if (rc != APR_SUCCESS) {

        ap_log_error(APLOG_MARK, APLOG_CRIT, rc, NULL, APLOGNO(00087)

                     "unable to replace stderr with error log file");

    }

    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, APLOGNO(00088)

                 "%s", description);

}

/* Create a child process running PROGNAME with a pipe connected to

 * the childs stdin.  The write-end of the pipe will be placed in

 * *FPIN on successful return.  If dummy_stderr is non-zero, the

 * stderr for the child will be the same as the stdout of the parent.

 * Otherwise the child will inherit the stderr from the parent. */

static int log_child(apr_pool_t *p, const char *progname,

                     apr_file_t **fpin, apr_cmdtype_e cmdtype,

                     int dummy_stderr)

{

    /* 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;

    apr_file_t *errfile;

    if (((rc = apr_procattr_create(&procattr, p)) == APR_SUCCESS)

        && ((rc = apr_procattr_dir_set(procattr,

                                       ap_server_root)) == APR_SUCCESS)

        && ((rc = apr_procattr_cmdtype_set(procattr, cmdtype)) == 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;

        apr_tokenize_to_argv(progname, &args, p);

        procnew = (apr_proc_t *)apr_pcalloc(p, sizeof(*procnew));

        if (dummy_stderr) {

            if ((rc = apr_file_open_stdout(&errfile, p)) == APR_SUCCESS)

                rc = apr_procattr_child_err_set(procattr, errfile, NULL);

        }

        rc = apr_proc_create(procnew, args[0], (const char * const *)args,

                             NULL, procattr, p);

        if (rc == APR_SUCCESS) {

            apr_pool_note_subprocess(p, procnew, APR_KILL_AFTER_TIMEOUT);

            (*fpin) = procnew->in;

            /* read handle to pipe not kept open, so no need to call

             * close_handle_in_child()

             */

        }

    }

    return rc;

}

/* Open the error log for the given server_rec.  If IS_MAIN is

 * non-zero, s is the main server. */

static int open_error_log(server_rec *s, int is_main, apr_pool_t *p)

{

    const char *fname;

    int rc;

    if (*s->error_fname == '|') {

        apr_file_t *dummy = NULL;

        apr_cmdtype_e cmdtype = APR_PROGRAM_ENV;

        fname = s->error_fname + 1;

        /* In 2.4 favor PROGRAM_ENV, accept "||prog" syntax for compatibility

         * and "|$cmd" to override the default.

         * Any 2.2 backport would continue to favor SHELLCMD_ENV so there

         * accept "||prog" to override, and "|$cmd" to ease conversion.

         */

        if (*fname == '|')

            ++fname;

        if (*fname == '$') {

            cmdtype = APR_SHELLCMD_ENV;

            ++fname;

        }

        /* Spawn a new child logger.  If this is the main server_rec,

         * the new child must use a dummy stderr since the current

         * stderr might be a pipe to the old logger.  Otherwise, the

         * child inherits the parents stderr. */

        rc = log_child(p, fname, &dummy, cmdtype, is_main);

        if (rc != APR_SUCCESS) {

            ap_log_error(APLOG_MARK, APLOG_STARTUP, rc, ap_server_conf, APLOGNO(00089)

                         "Couldn't start ErrorLog process '%s'.",

                         s->error_fname + 1);

            return DONE;

        }

        s->error_log = dummy;

    }

#ifdef HAVE_SYSLOG

    else if (strcmp(s->error_fname, "syslog") == 0

             || strncmp(s->error_fname, "syslog:", 7) == 0) {

        if ((fname = strchr(s->error_fname, ':'))) {

            /* s->error_fname could be [level]:[tag] (see #60525) */

            const char *tag;

            apr_size_t flen;

            const TRANS *fac;

            fname++;

            tag = ap_strchr_c(fname, ':');

            if (tag) {

                flen = tag - fname;

                tag++;

                if (*tag == '\0') {

                    tag = ap_server_argv0;

                }

            } else {

                flen = strlen(fname);

                tag = ap_server_argv0;

            }

            if (flen == 0) {

                /* Was something like syslog::foobar */

                openlog(tag, LOG_NDELAY|LOG_CONS|LOG_PID, LOG_LOCAL7);

            } else {

                for (fac = facilities; fac->t_name; fac++) {

                    if (!strncasecmp(fname, fac->t_name, flen)) {

                        openlog(tag, LOG_NDELAY|LOG_CONS|LOG_PID,

                                fac->t_val);

                        s->error_log = NULL;

                        return OK;

                    }

                }

                /* Huh? Invalid level name? */

                ap_log_error(APLOG_MARK, APLOG_STARTUP, APR_EBADPATH, NULL, APLOGNO(10036)

                             "%s: could not open syslog error log %s.",

                              ap_server_argv0, fname);

                return DONE;

            }

        }

        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, ap_server_conf, APLOGNO(00090)

                         "%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, ap_server_conf, APLOGNO(00091)

                         "%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_pool_t *stderr_p;

    server_rec *virt, *q;

    int replace_stderr;

    /* Register to throw away the read_handles list when we

     * cleanup plog.  Upon fork() for the apache children,

     * this read_handles list is closed so only the parent

     * can relaunch a lost log child.  These read handles

     * are always closed on exec.

     * We won't care what happens to our stderr log child

     * between log phases, so we don't mind losing stderr's

     * read_handle a little bit early.

     */

    apr_pool_cleanup_register(p, &read_handles, ap_pool_cleanup_set_null,

                              apr_pool_cleanup_null);

    /* HERE we need a stdout log that outlives plog.

     * We *presume* the parent of plog is a process

     * or global pool which spans server restarts.

     * Create our stderr_pool as a child of the plog's

     * parent pool.

     */

    apr_pool_create(&stderr_p, apr_pool_parent_get(p));

    apr_pool_tag(stderr_p, "stderr_pool");

    if (open_error_log(s_main, 1, stderr_p) != OK) {

        return DONE;

    }

    replace_stderr = 1;

    if (s_main->error_log) {

        apr_status_t rv;

        /* Replace existing stderr with new log. */

        apr_file_flush(s_main->error_log);

        rv = apr_file_dup2(stderr_log, s_main->error_log, stderr_p);

        if (rv != APR_SUCCESS) {

            ap_log_error(APLOG_MARK, APLOG_CRIT, rv, s_main, APLOGNO(00092)

                         "unable to replace stderr with error_log");

        }

        else {

            /* We are done with stderr_pool, close it, killing

             * the previous generation's stderr logger

             */

            if (stderr_pool)

                apr_pool_destroy(stderr_pool);

            stderr_pool = stderr_p;

            replace_stderr = 0;

            /*

             * Now that we have dup'ed s_main->error_log to stderr_log

             * close it and set s_main->error_log to stderr_log. This avoids

             * this fd being inherited by the next piped logger who would

             * keep open the writing end of the pipe that this one uses

             * as stdin. This in turn would prevent the piped logger from

             * exiting.

             */

            apr_file_close(s_main->error_log);

            s_main->error_log = stderr_log;

        }

    }

    /* 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

     *      errno-as-apr_status_t is also non-portable

     */

#ifdef WIN32

#define NULL_DEVICE "nul"

#else

#define NULL_DEVICE "/dev/null"

#endif

    if (replace_stderr && freopen(NULL_DEVICE, "w", stderr) == NULL) {

        ap_log_error(APLOG_MARK, APLOG_CRIT, errno, s_main, APLOGNO(00093)

                     "unable to replace stderr with %s", NULL_DEVICE);

    }

    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, 0, 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 int cpystrn(char *buf, const char *arg, int buflen)

{

    char *end;

    if (!arg)

        return 0;

    end = apr_cpystrn(buf, arg, buflen);

    return end - buf;

}

static int log_remote_address(const ap_errorlog_info *info, const char *arg,

                              char *buf, int buflen)

{

    if (info->r && !(arg && *arg == 'c'))

        return apr_snprintf(buf, buflen, "%s:%d", info->r->useragent_ip,

                            info->r->useragent_addr ? info->r->useragent_addr->port : 0);

    else if (info->c)

        return apr_snprintf(buf, buflen, "%s:%d", info->c->client_ip,

                            info->c->client_addr ? info->c->client_addr->port : 0);

    else

        return 0;

}

static int log_local_address(const ap_errorlog_info *info, const char *arg,

                             char *buf, int buflen)

{

    if (info->c)

        return apr_snprintf(buf, buflen, "%s:%d", info->c->local_ip,

                            info->c->local_addr->port);

    else

        return 0;

}

static int log_pid(const ap_errorlog_info *info, const char *arg,

                   char *buf, int buflen)

{

    pid_t pid = getpid();

    return apr_snprintf(buf, buflen, "%" APR_PID_T_FMT, pid);

}

static int log_tid(const ap_errorlog_info *info, const char *arg,

                   char *buf, int buflen)

{

#if APR_HAS_THREADS

    int result;

#endif

#if HAVE_GETTID

    if (arg && *arg == 'g') {

        pid_t tid = syscall(SYS_gettid);

        if (tid == -1)

            return 0;

        return apr_snprintf(buf, buflen, "%"APR_PID_T_FMT, tid);

    }

#endif

#if APR_HAS_THREADS

    if (ap_mpm_query(AP_MPMQ_IS_THREADED, &result) == APR_SUCCESS

        && result != AP_MPMQ_NOT_SUPPORTED)

    {

        apr_os_thread_t tid = apr_os_thread_current();

        return apr_snprintf(buf, buflen, "%pT", &tid;;

    }

#endif

    return 0;

}

static int log_ctime(const ap_errorlog_info *info, const char *arg,

                     char *buf, int buflen)

{

    int time_len = buflen;

    int option = AP_CTIME_OPTION_NONE;

    while (arg && *arg) {

        switch (*arg) {

            case 'u':   option |= AP_CTIME_OPTION_USEC;

                        break;

            case 'c':   option |= AP_CTIME_OPTION_COMPACT;

                        break;

        }

        arg++;

    }

    ap_recent_ctime_ex(buf, apr_time_now(), option, &time_len);

    /* ap_recent_ctime_ex includes the trailing \0 in time_len */

    return time_len - 1;

}

static int log_loglevel(const ap_errorlog_info *info, const char *arg,

                        char *buf, int buflen)

{

    if (info->level < 0)

        return 0;

    else

        return cpystrn(buf, priorities[info->level].t_name, buflen);

}

static int log_log_id(const ap_errorlog_info *info, const char *arg,

                      char *buf, int buflen)

{

    /*

     * C: log conn log_id if available,

     * c: log conn log id if available and not a once-per-request log line

     * else: log request log id if available

     */

    if (arg && !strcasecmp(arg, "c")) {

        if (info->c && (*arg != 'C' || !info->r)) {

            return cpystrn(buf, info->c->log_id, buflen);

        }

    }

    else if (info->rmain) {

        return cpystrn(buf, info->rmain->log_id, buflen);

    }

    return 0;

}

static int log_keepalives(const ap_errorlog_info *info, const char *arg,

                          char *buf, int buflen)

{

    if (!info->c)

        return 0;

    return apr_snprintf(buf, buflen, "%d", info->c->keepalives);

}

static int log_module_name(const ap_errorlog_info *info, const char *arg,

                           char *buf, int buflen)

{

    return cpystrn(buf, ap_find_module_short_name(info->module_index), buflen);

}

static int log_file_line(const ap_errorlog_info *info, const char *arg,

                         char *buf, int buflen)

{

    if (info->file == NULL) {

        return 0;

    }

    else {

        const char *file = info->file;

#if defined(_OSD_POSIX) || defined(WIN32) || defined(__MVS__)

        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 == ')') {

                *e = '\0';

            }

            file = tmp;

        }

#else /* _OSD_POSIX || WIN32 */

        const char *p;

        /* On Unix, __FILE__ may be an absolute path in a

         * VPATH build. */

        if (file[0] == '/' && (p = ap_strrchr_c(file, '/')) != NULL) {

            file = p + 1;

        }

#endif /*_OSD_POSIX || WIN32 */

        return apr_snprintf(buf, buflen, "%s(%d)", file, info->line);

    }

}

static int log_apr_status(const ap_errorlog_info *info, const char *arg,

                          char *buf, int buflen)

{

    apr_status_t status = info->status;

    int len;

    if (!status)

        return 0;

    if (status < APR_OS_START_EAIERR) {

        len = apr_snprintf(buf, buflen, "(%d)", status);

    }

    else if (status < APR_OS_START_SYSERR) {

        len = apr_snprintf(buf, buflen, "(EAI %d)",

                           status - APR_OS_START_EAIERR);

    }

    else if (status < 100000 + APR_OS_START_SYSERR) {

        len = apr_snprintf(buf, buflen, "(OS %d)",

                           status - APR_OS_START_SYSERR);

    }

    else {

        len = apr_snprintf(buf, buflen, "(os 0x%08x)",

                           status - APR_OS_START_SYSERR);

    }

    apr_strerror(status, buf + len, buflen - len);

    len += strlen(buf + len);

    return len;

}

static int log_server_name(const ap_errorlog_info *info, const char *arg,

                           char *buf, int buflen)

{

    if (info->r)

        return cpystrn(buf, ap_get_server_name((request_rec *)info->r), buflen);

    return 0;

}

static int log_virtual_host(const ap_errorlog_info *info, const char *arg,

                            char *buf, int buflen)

{

    if (info->s)

        return cpystrn(buf, info->s->server_hostname, buflen);

    return 0;

}

static int log_table_entry(const apr_table_t *table, const char *name,

                           char *buf, int buflen)

{

#ifndef AP_UNSAFE_ERROR_LOG_UNESCAPED

    const char *value;

    char scratch[MAX_STRING_LEN];

    if ((value = apr_table_get(table, name)) != NULL) {

        ap_escape_errorlog_item(scratch, value, MAX_STRING_LEN);

        return cpystrn(buf, scratch, buflen);

    }

    return 0;

#else

    return cpystrn(buf, apr_table_get(table, name), buflen);

#endif

}

static int log_header(const ap_errorlog_info *info, const char *arg,

                      char *buf, int buflen)

{

    if (info->r)

        return log_table_entry(info->r->headers_in, arg, buf, buflen);

    return 0;

}

static int log_note(const ap_errorlog_info *info, const char *arg,

                      char *buf, int buflen)

{

    /* XXX: maybe escaping the entry is not necessary for notes? */

    if (info->r)

        return log_table_entry(info->r->notes, arg, buf, buflen);

    return 0;

}

static int log_env_var(const ap_errorlog_info *info, const char *arg,

                      char *buf, int buflen)

{

    if (info->r)

        return log_table_entry(info->r->subprocess_env, arg, buf, buflen);

    return 0;

}

static int core_generate_log_id(const conn_rec *c, const request_rec *r,

                                 const char **idstring)

{

    apr_uint64_t id, tmp;

    pid_t pid;

    int len;

    char *encoded;

    if (r && r->request_time) {

        id = (apr_uint64_t)r->request_time;

    }

    else {

        id = (apr_uint64_t)apr_time_now();

    }

    pid = getpid();

    if (sizeof(pid_t) > 2) {

        tmp = pid;

        tmp = tmp << 40;

        id ^= tmp;

        pid = pid >> 24;

        tmp = pid;

        tmp = tmp << 56;

        id ^= tmp;

    }

    else {

        tmp = pid;

        tmp = tmp << 40;

        id ^= tmp;

    }

#if APR_HAS_THREADS

    {

        apr_uintptr_t tmp2 = (apr_uintptr_t)c->current_thread;