/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>


static char *ngx_error_log(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
static char *ngx_log_set_levels(ngx_conf_t *cf, ngx_log_t *log);
static void ngx_log_insert(ngx_log_t *log, ngx_log_t *new_log);


static ngx_command_t  ngx_errlog_commands[] = {

    {ngx_string("error_log"),
     NGX_MAIN_CONF|NGX_CONF_1MORE,
     ngx_error_log,
     0,
     0,
     NULL},

    ngx_null_command
};


static ngx_core_module_t  ngx_errlog_module_ctx = {
    ngx_string("errlog"),
    NULL,
    NULL
};


ngx_module_t  ngx_errlog_module = {
    NGX_MODULE_V1,
    &ngx_errlog_module_ctx,                /* module context */
    ngx_errlog_commands,                   /* module directives */
    NGX_CORE_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_log_t        ngx_log;
static ngx_open_file_t  ngx_log_file;
ngx_uint_t              ngx_use_stderr = 1;


static ngx_str_t err_levels[] = {
    ngx_null_string,
    ngx_string("emerg"),
    ngx_string("alert"),
    ngx_string("crit"),
    ngx_string("error"),
    ngx_string("warn"),
    ngx_string("notice"),
    ngx_string("info"),
    ngx_string("debug")
};

static const char *debug_levels[] = {
    "debug_core", "debug_alloc", "debug_mutex", "debug_event",
    "debug_http", "debug_mail", "debug_mysql"
};


#if (NGX_HAVE_VARIADIC_MACROS)

void
ngx_log_error_core(ngx_uint_t level, ngx_log_t *log, ngx_err_t err,
    const char *fmt, ...)

#else

void
ngx_log_error_core(ngx_uint_t level, ngx_log_t *log, ngx_err_t err,
    const char *fmt, va_list args)

#endif
{
#if (NGX_HAVE_VARIADIC_MACROS)
    va_list      args;
#endif
    u_char      *p, *last, *msg;
    u_char       errstr[NGX_MAX_ERROR_STR];
    ngx_uint_t   wrote_stderr, debug_connection;

    last = errstr + NGX_MAX_ERROR_STR;

    ngx_memcpy(errstr, ngx_cached_err_log_time.data,
               ngx_cached_err_log_time.len);

    p = errstr + ngx_cached_err_log_time.len;

    p = ngx_slprintf(p, last, " [%V] ", &err_levels[level]);

    /* pid#tid */
    p = ngx_slprintf(p, last, "%P#" NGX_TID_T_FMT ": ",
                    ngx_log_pid, ngx_log_tid);

    if (log->connection) {
        p = ngx_slprintf(p, last, "*%uA ", log->connection);
    }

    msg = p;

#if (NGX_HAVE_VARIADIC_MACROS)

    va_start(args, fmt);
    p = ngx_vslprintf(p, last, fmt, args);
    va_end(args);

#else

    p = ngx_vslprintf(p, last, fmt, args);

#endif

    if (err) {
        p = ngx_log_errno(p, last, err);
    }

    if (level != NGX_LOG_DEBUG && log->handler) {
        p = log->handler(log, p, last - p);
    }

    if (p > last - NGX_LINEFEED_SIZE) {
        p = last - NGX_LINEFEED_SIZE;
    }

    ngx_linefeed(p);

    wrote_stderr = 0;
    debug_connection = (log->log_level & NGX_LOG_DEBUG_CONNECTION) != 0;

    while (log) {

        if (log->log_level < level && !debug_connection) {
            break;
        }

        (void) ngx_write_fd(log->file->fd, errstr, p - errstr);

        if (log->file->fd == ngx_stderr) {
            wrote_stderr = 1;
        }

        log = log->next;
    }

    if (!ngx_use_stderr
        || level > NGX_LOG_WARN
        || wrote_stderr)
    {
        return;
    }

    msg -= (7 + err_levels[level].len + 3);

    (void) ngx_sprintf(msg, "nginx: [%V] ", &err_levels[level]);

    (void) ngx_write_console(ngx_stderr, msg, p - msg);
}


#if !(NGX_HAVE_VARIADIC_MACROS)

void ngx_cdecl
ngx_log_error(ngx_uint_t level, ngx_log_t *log, ngx_err_t err,
    const char *fmt, ...)
{
    va_list  args;

    if (log->log_level >= level) {
        va_start(args, fmt);
        ngx_log_error_core(level, log, err, fmt, args);
        va_end(args);
    }
}


void ngx_cdecl
ngx_log_debug_core(ngx_log_t *log, ngx_err_t err, const char *fmt, ...)
{
    va_list  args;

    va_start(args, fmt);
    ngx_log_error_core(NGX_LOG_DEBUG, log, err, fmt, args);
    va_end(args);
}

#endif


void ngx_cdecl
ngx_log_abort(ngx_err_t err, const char *fmt, ...)
{
    u_char   *p;
    va_list   args;
    u_char    errstr[NGX_MAX_CONF_ERRSTR];

    va_start(args, fmt);
    p = ngx_vsnprintf(errstr, sizeof(errstr) - 1, fmt, args);
    va_end(args);

    ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, err,
                  "%*s", p - errstr, errstr);
}


void ngx_cdecl
ngx_log_stderr(ngx_err_t err, const char *fmt, ...)
{
    u_char   *p, *last;
    va_list   args;
    u_char    errstr[NGX_MAX_ERROR_STR];

    last = errstr + NGX_MAX_ERROR_STR;
    p = errstr + 7;

    ngx_memcpy(errstr, "nginx: ", 7);

    va_start(args, fmt);
    p = ngx_vslprintf(p, last, fmt, args);
    va_end(args);

    if (err) {
        p = ngx_log_errno(p, last, err);
    }

    if (p > last - NGX_LINEFEED_SIZE) {
        p = last - NGX_LINEFEED_SIZE;
    }

    ngx_linefeed(p);

    (void) ngx_write_console(ngx_stderr, errstr, p - errstr);
}


u_char *
ngx_log_errno(u_char *buf, u_char *last, ngx_err_t err)
{
    if (buf > last - 50) {

        /* leave a space for an error code */

        buf = last - 50;
        *buf++ = '.';
        *buf++ = '.';
        *buf++ = '.';
    }

#if (NGX_WIN32)
    buf = ngx_slprintf(buf, last, ((unsigned) err < 0x80000000)
                                       ? " (%d: " : " (%Xd: ", err);
#else
    buf = ngx_slprintf(buf, last, " (%d: ", err);
#endif

    buf = ngx_strerror(err, buf, last - buf);

    if (buf < last) {
        *buf++ = ')';
    }

    return buf;
}


ngx_log_t *
ngx_log_init(u_char *prefix)
{
    u_char  *p, *name;
    size_t   nlen, plen;

    ngx_log.file = &ngx_log_file;
    ngx_log.log_level = NGX_LOG_NOTICE;

    name = (u_char *) NGX_ERROR_LOG_PATH;

    /*
     * we use ngx_strlen() here since BCC warns about
     * condition is always false and unreachable code
     */

    nlen = ngx_strlen(name);

    if (nlen == 0) {
        ngx_log_file.fd = ngx_stderr;
        return &ngx_log;
    }

    p = NULL;

#if (NGX_WIN32)
    if (name[1] != ':') {
#else
    if (name[0] != '/') {
#endif

        if (prefix) {
            plen = ngx_strlen(prefix);

        } else {
#ifdef NGX_PREFIX
            prefix = (u_char *) NGX_PREFIX;
            plen = ngx_strlen(prefix);
#else
            plen = 0;
#endif
        }

        if (plen) {
            name = malloc(plen + nlen + 2);
            if (name == NULL) {
                return NULL;
            }

            p = ngx_cpymem(name, prefix, plen);

            if (!ngx_path_separator(*(p - 1))) {
                *p++ = '/';
            }

            ngx_cpystrn(p, (u_char *) NGX_ERROR_LOG_PATH, nlen + 1);

            p = name;
        }
    }

    ngx_log_file.fd = ngx_open_file(name, NGX_FILE_APPEND,
                                    NGX_FILE_CREATE_OR_OPEN,
                                    NGX_FILE_DEFAULT_ACCESS);

    if (ngx_log_file.fd == NGX_INVALID_FILE) {
        ngx_log_stderr(ngx_errno,
                       "[alert] could not open error log file: "
                       ngx_open_file_n " \"%s\" failed", name);
#if (NGX_WIN32)
        ngx_event_log(ngx_errno,
                       "could not open error log file: "
                       ngx_open_file_n " \"%s\" failed", name);
#endif

        ngx_log_file.fd = ngx_stderr;
    }

    if (p) {
        ngx_free(p);
    }

    return &ngx_log;
}


ngx_int_t
ngx_log_open_default(ngx_cycle_t *cycle)
{
    static ngx_str_t  error_log = ngx_string(NGX_ERROR_LOG_PATH);

    if (cycle->new_log.file == NULL) {
        cycle->new_log.file = ngx_conf_open_file(cycle, &error_log);
        if (cycle->new_log.file == NULL) {
            return NGX_ERROR;
        }

        cycle->new_log.log_level = NGX_LOG_ERR;
    }

    return NGX_OK;
}


ngx_int_t
ngx_log_redirect_stderr(ngx_cycle_t *cycle)
{
    ngx_fd_t  fd;

    if (cycle->log_use_stderr) {
        return NGX_OK;
    }

    fd = cycle->log->file->fd;

    if (fd != ngx_stderr) {
        if (ngx_set_stderr(fd) == NGX_FILE_ERROR) {
            ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                          ngx_set_stderr_n " failed");

            return NGX_ERROR;
        }
    }

    return NGX_OK;
}


static char *
ngx_log_set_levels(ngx_conf_t *cf, ngx_log_t *log)
{
    ngx_uint_t   i, n, d, found;
    ngx_str_t   *value;

    if (cf->args->nelts == 2) {
        log->log_level = NGX_LOG_ERR;
        return NGX_CONF_OK;
    }

    value = cf->args->elts;

    for (i = 2; i < cf->args->nelts; i++) {
        found = 0;

        for (n = 1; n <= NGX_LOG_DEBUG; n++) {
            if (ngx_strcmp(value[i].data, err_levels[n].data) == 0) {

                if (log->log_level != 0) {
                    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                       "duplicate log level \"%V\"",
                                       &value[i]);
                    return NGX_CONF_ERROR;
                }

                log->log_level = n;
                found = 1;
                break;
            }
        }

        for (n = 0, d = NGX_LOG_DEBUG_FIRST; d <= NGX_LOG_DEBUG_LAST; d <<= 1) {
            if (ngx_strcmp(value[i].data, debug_levels[n++]) == 0) {
                if (log->log_level & ~NGX_LOG_DEBUG_ALL) {
                    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                       "invalid log level \"%V\"",
                                       &value[i]);
                    return NGX_CONF_ERROR;
                }

                log->log_level |= d;
                found = 1;
                break;
            }
        }


        if (!found) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "invalid log level \"%V\"", &value[i]);
            return NGX_CONF_ERROR;
        }
    }

    if (log->log_level == NGX_LOG_DEBUG) {
        log->log_level = NGX_LOG_DEBUG_ALL;
    }

    return NGX_CONF_OK;
}


static char *
ngx_error_log(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_log_t  *dummy;

    dummy = &cf->cycle->new_log;

    return ngx_log_set_log(cf, &dummy);
}


char *
ngx_log_set_log(ngx_conf_t *cf, ngx_log_t **head)
{
    ngx_log_t  *new_log;
    ngx_str_t  *value, name;

    if (*head != NULL && (*head)->log_level == 0) {
        new_log = *head;

    } else {

        new_log = ngx_pcalloc(cf->pool, sizeof(ngx_log_t));
        if (new_log == NULL) {
            return NGX_CONF_ERROR;
        }

        if (*head == NULL) {
            *head = new_log;
        }
    }

    value = cf->args->elts;

    if (ngx_strcmp(value[1].data, "stderr") == 0) {
        ngx_str_null(&name);
        cf->cycle->log_use_stderr = 1;

    } else {
        name = value[1];
    }

    new_log->file = ngx_conf_open_file(cf->cycle, &name);
    if (new_log->file == NULL) {
        return NGX_CONF_ERROR;
    }

    if (ngx_log_set_levels(cf, new_log) != NGX_CONF_OK) {
        return NGX_CONF_ERROR;
    }

    if (*head != new_log) {
        ngx_log_insert(*head, new_log);
    }

    return NGX_CONF_OK;
}


static void
ngx_log_insert(ngx_log_t *log, ngx_log_t *new_log)
{
    ngx_log_t  tmp;

    if (new_log->log_level > log->log_level) {

        /*
         * list head address is permanent, insert new log after
         * head and swap its contents with head
         */

        tmp = *log;
        *log = *new_log;
        *new_log = tmp;

        log->next = new_log;
        return;
    }

    while (log->next) {
        if (new_log->log_level > log->next->log_level) {
            new_log->next = log->next;
            log->next = new_log;
            return;
        }

        log = log->next;
    }

    log->next = new_log;
}