/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 1996
 *      David L. Nugent.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY DAVID L. NUGENT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL DAVID L. NUGENT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <ctype.h>
#include <err.h>
#include <fcntl.h>
#include <string.h>
#include <stdarg.h>

#include "pw.h"

static FILE     *logfile = NULL;

void
pw_log(struct userconf * cnf, int mode, int which, char const * fmt,...)
{
        va_list         argp;
        time_t          now;
        const char      *cp, *name;
        struct tm       *t;
        int             fd, i, rlen;
        char            nfmt[256], sname[32];

        if (cnf->logfile == NULL || cnf->logfile[0] == '\0') {
                return;
        }

        if (logfile == NULL) {
                /* With umask==0 we need to control file access modes on create */
                fd = open(cnf->logfile, O_WRONLY | O_CREAT | O_APPEND, 0600);
                if (fd == -1) {
                        return;
                }
                logfile = fdopen(fd, "a");
                if (logfile == NULL) {
                        return;
                }
        }

        if ((name = getenv("LOGNAME")) == NULL &&
            (name = getenv("USER")) == NULL) {
                strcpy(sname, "unknown");
        } else {
                /*
                 * Since "name" will be embedded in a printf-like format,
                 * we must sanitize it:
                 *
                 *    Limit its length so other information in the message
                 *    is not truncated
                 *
                 *    Squeeze out embedded whitespace for the benefit of
                 *    log file parsers
                 *
                 *    Escape embedded % characters with another %
                 */
                for (i = 0, cp = name;
                    *cp != '\0' && i < (int)sizeof(sname) - 1; cp++) {
                        if (*cp == '%') {
                                if (i < (int)sizeof(sname) - 2) {
                                        sname[i++] = '%';
                                        sname[i++] = '%';
                                } else {
                                        break;
                                }
                        } else if (!isspace(*cp)) {
                                sname[i++] = *cp;
                        } /* else do nothing */
                }
                if (i == 0) {
                        strcpy(sname, "unknown");
                } else {
                        sname[i] = '\0';
                }
        }
        now = time(NULL);
        t = localtime(&now);
        /* ISO 8601 International Standard Date format */
        strftime(nfmt, sizeof nfmt, "%Y-%m-%d %T ", t);
        rlen = sizeof(nfmt) - strlen(nfmt);
        if (rlen <= 0 || snprintf(nfmt + strlen(nfmt), rlen,
            "[%s:%s%s] %s\n", sname, Which[which], Modes[mode],
            fmt) >= rlen) {
                warnx("log format overflow, user name=%s", sname);
        } else {
                va_start(argp, fmt);
                vfprintf(logfile, nfmt, argp);
                va_end(argp);
                fflush(logfile);
        }
}