pw/pw_log.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (C) 1996
   5  *      David L. Nugent.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY DAVID L. NUGENT AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL DAVID L. NUGENT OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #ifndef lint
  30 static const char rcsid[] =
  31   "$FreeBSD$";
  32 #endif /* not lint */
  33
  34 #include <ctype.h>
  35 #include <err.h>
  36 #include <fcntl.h>
  37 #include <string.h>
  38 #include <stdarg.h>
  39
  40 #include "pw.h"
  41
  42 static FILE     *logfile = NULL;
  43
  44 void
  45 pw_log(struct userconf * cnf, int mode, int which, char const * fmt,...)
  46 {
  47         va_list         argp;
  48         time_t          now;
  49         const char      *cp, *name;
  50         struct tm       *t;
  51         int             fd, i, rlen;
  52         char            nfmt[256], sname[32];
  53
  54         if (cnf->logfile == NULL || cnf->logfile[0] == '\0') {
  55                 return;
  56         }
  57
  58         if (logfile == NULL) {
  59                 /* With umask==0 we need to control file access modes on create */
  60                 fd = open(cnf->logfile, O_WRONLY | O_CREAT | O_APPEND, 0600);
  61                 if (fd == -1) {
  62                         return;
  63                 }
  64                 logfile = fdopen(fd, "a");
  65                 if (logfile == NULL) {
  66                         return;
  67                 }
  68         }
  69
  70         if ((name = getenv("LOGNAME")) == NULL &&
  71             (name = getenv("USER")) == NULL) {
  72                 strcpy(sname, "unknown");
  73         } else {
  74                 /*
  75                  * Since "name" will be embedded in a printf-like format,
  76                  * we must sanitize it:
  77                  *
  78                  *    Limit its length so other information in the message
  79                  *    is not truncated
  80                  *
  81                  *    Squeeze out embedded whitespace for the benefit of
  82                  *    log file parsers
  83                  *
  84                  *    Escape embedded % characters with another %
  85                  */
  86                 for (i = 0, cp = name;
  87                     *cp != '\0' && i < (int)sizeof(sname) - 1; cp++) {
  88                         if (*cp == '%') {
  89                                 if (i < (int)sizeof(sname) - 2) {
  90                                         sname[i++] = '%';
  91                                         sname[i++] = '%';
  92                                 } else {
  93                                         break;
  94                                 }
  95                         } else if (!isspace(*cp)) {
  96                                 sname[i++] = *cp;
  97                         } /* else do nothing */
  98                 }
  99                 if (i == 0) {
 100                         strcpy(sname, "unknown");
 101                 } else {
 102                         sname[i] = '\0';
 103                 }
 104         }
 105         now = time(NULL);
 106         t = localtime(&now);
 107         /* ISO 8601 International Standard Date format */
 108         strftime(nfmt, sizeof nfmt, "%Y-%m-%d %T ", t);
 109         rlen = sizeof(nfmt) - strlen(nfmt);
 110         if (rlen <= 0 || snprintf(nfmt + strlen(nfmt), rlen,
 111             "[%s:%s%s] %s\n", sname, Which[which], Modes[mode],
 112             fmt) >= rlen) {
 113                 warnx("log format overflow, user name=%s", sname);
 114         } else {
 115                 va_start(argp, fmt);
 116                 vfprintf(logfile, nfmt, argp);
 117                 va_end(argp);
 118                 fflush(logfile);
 119         }
 120 }