/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* lib/kadm5/logger.c */
/*
 * Copyright 1995, 2007 by the Massachusetts Institute of Technology.
 * All Rights Reserved.
 *
 * Export of this software from the United States of America may
 *   require a specific license from the United States Government.
 *   It is the responsibility of any person or organization contemplating
 *   export to obtain such a license before exporting.
 *
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  Furthermore if you modify this software you must label
 * your software as modified software and not distribute it in such a
 * fashion that it might be confused with the original M.I.T. software.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 */

/* KADM5 wants non-syslog log files to contain syslog-like entries */
#define VERBOSE_LOGS

/*
 * logger.c     - Handle logging functions for those who want it.
 */
#include "k5-int.h"
#include "adm_proto.h"
#include "com_err.h"
#include <stdio.h>
#include <ctype.h>
#ifdef  HAVE_SYSLOG_H
#include <syslog.h>
#endif  /* HAVE_SYSLOG_H */
#include <stdarg.h>

#define KRB5_KLOG_MAX_ERRMSG_SIZE       2048
#ifndef MAXHOSTNAMELEN
#define MAXHOSTNAMELEN  256
#endif  /* MAXHOSTNAMELEN */

/* This is to assure that we have at least one match in the syslog stuff */
#ifndef LOG_AUTH
#define LOG_AUTH        0
#endif  /* LOG_AUTH */
#ifndef LOG_ERR
#define LOG_ERR         0
#endif  /* LOG_ERR */

#define lspec_parse_err_1       "%s: cannot parse <%s>\n"
#define lspec_parse_err_2       "%s: warning - logging entry syntax error\n"
#define log_file_err            "%s: error writing to %s\n"
#define log_device_err          "%s: error writing to %s device\n"
#define log_ufo_string          "?\?\?" /* nb: avoid trigraphs */
#define log_emerg_string        "EMERGENCY"
#define log_alert_string        "ALERT"
#define log_crit_string         "CRITICAL"
#define log_err_string          "Error"
#define log_warning_string      "Warning"
#define log_notice_string       "Notice"
#define log_info_string         "info"
#define log_debug_string        "debug"

/*
 * Output logging.
 *
 * Output logging is now controlled by the configuration file.  We can specify
 * the following syntaxes under the [logging]->entity specification.
 *      FILE<opentype><pathname>
 *      SYSLOG[=<severity>[:<facility>]]
 *      STDERR
 *      CONSOLE
 *      DEVICE=<device-spec>
 *
 * Where:
 *      <opentype> is ":" for open/append, "=" for open/create.
 *      <pathname> is a valid path name.
 *      <severity> is one of: (default = ERR)
 *              EMERG
 *              ALERT
 *              CRIT
 *              ERR
 *              WARNING
 *              NOTICE
 *              INFO
 *              DEBUG
 *      <facility> is one of: (default = AUTH)
 *              KERN
 *              USER
 *              MAIL
 *              DAEMON
 *              AUTH
 *              LPR
 *              NEWS
 *              UUCP
 *              CRON
 *              LOCAL0..LOCAL7
 *      <device-spec> is a valid device specification.
 */
struct log_entry {
    enum log_type { K_LOG_FILE,
                    K_LOG_SYSLOG,
                    K_LOG_STDERR,
                    K_LOG_CONSOLE,
                    K_LOG_DEVICE,
                    K_LOG_NONE } log_type;
    krb5_pointer log_2free;
    union log_union {
        struct log_file {
            FILE        *lf_filep;
            char        *lf_fname;
        } log_file;
        struct log_syslog {
            int         ls_facility;
            int         ls_severity;
        } log_syslog;
        struct log_device {
            FILE        *ld_filep;
            char        *ld_devname;
        } log_device;
    } log_union;
};
#define lfu_filep       log_union.log_file.lf_filep
#define lfu_fname       log_union.log_file.lf_fname
#define lsu_facility    log_union.log_syslog.ls_facility
#define lsu_severity    log_union.log_syslog.ls_severity
#define ldu_filep       log_union.log_device.ld_filep
#define ldu_devname     log_union.log_device.ld_devname

struct log_control {
    struct log_entry    *log_entries;
    int                 log_nentries;
    char                *log_whoami;
    char                *log_hostname;
    krb5_boolean        log_opened;
};

static struct log_control log_control = {
    (struct log_entry *) NULL,
    0,
    (char *) NULL,
    (char *) NULL,
    0
};
static struct log_entry def_log_entry;

/*
 * These macros define any special processing that needs to happen for
 * devices.  For unix, of course, this is hardly anything.
 */
#define DEVICE_OPEN(d, m)       fopen(d, m)
#define CONSOLE_OPEN(m)         fopen("/dev/console", m)
#define DEVICE_PRINT(f, m)      ((fprintf(f, "%s\r\n", m) >= 0) ?       \
                                 (fflush(f), 0) :                       \
                                 -1)
#define DEVICE_CLOSE(d)         fclose(d)


/*
 * klog_com_err_proc()  - Handle com_err(3) messages as specified by the
 *                        profile.
 */
static krb5_context err_context;

static void
klog_com_err_proc(const char *whoami, long int code, const char *format, va_list ap)
#if !defined(__cplusplus) && (__GNUC__ > 2)
    __attribute__((__format__(__printf__, 3, 0)))
#endif
    ;

static void
klog_com_err_proc(const char *whoami, long int code, const char *format, va_list ap)
{
    char        outbuf[KRB5_KLOG_MAX_ERRMSG_SIZE];
    int         lindex;
    const char  *actual_format;
#ifdef  HAVE_SYSLOG
    int         log_pri = -1;
#endif  /* HAVE_SYSLOG */
    char        *cp;
    char        *syslogp;

    if (whoami == NULL || format == NULL)
        return;

    /* Make the header */
    snprintf(outbuf, sizeof(outbuf), "%s: ", whoami);
    /*
     * Squirrel away address after header for syslog since syslog makes
     * a header
     */
    syslogp = &outbuf[strlen(outbuf)];

    /* If reporting an error message, separate it. */
    if (code) {
        const char *emsg;
        outbuf[sizeof(outbuf) - 1] = '\0';

        emsg = krb5_get_error_message (err_context, code);
        strncat(outbuf, emsg, sizeof(outbuf) - 1 - strlen(outbuf));
        strncat(outbuf, " - ", sizeof(outbuf) - 1 - strlen(outbuf));
        krb5_free_error_message(err_context, emsg);
    }
    cp = &outbuf[strlen(outbuf)];

    actual_format = format;
#ifdef  HAVE_SYSLOG
    /*
     * This is an unpleasant hack.  If the first character is less than
     * 8, then we assume that it is a priority.
     *
     * Since it is not guaranteed that there is a direct mapping between
     * syslog priorities (e.g. Ultrix and old BSD), we resort to this
     * intermediate representation.
     */
    if ((((unsigned char) *format) > 0) && (((unsigned char) *format) <= 8)) {
        actual_format = (format + 1);
        switch ((unsigned char) *format) {
#ifdef  LOG_EMERG
        case 1:
            log_pri = LOG_EMERG;
            break;
#endif /* LOG_EMERG */
#ifdef  LOG_ALERT
        case 2:
            log_pri = LOG_ALERT;
            break;
#endif /* LOG_ALERT */
#ifdef  LOG_CRIT
        case 3:
            log_pri = LOG_CRIT;
            break;
#endif /* LOG_CRIT */
        default:
        case 4:
            log_pri = LOG_ERR;
            break;
#ifdef  LOG_WARNING
        case 5:
            log_pri = LOG_WARNING;
            break;
#endif /* LOG_WARNING */
#ifdef  LOG_NOTICE
        case 6:
            log_pri = LOG_NOTICE;
            break;
#endif /* LOG_NOTICE */
#ifdef  LOG_INFO
        case 7:
            log_pri = LOG_INFO;
            break;
#endif /* LOG_INFO */
#ifdef  LOG_DEBUG
        case 8:
            log_pri = LOG_DEBUG;
            break;
#endif /* LOG_DEBUG */
        }
    }
#endif  /* HAVE_SYSLOG */

    /* Now format the actual message */
    vsnprintf(cp, sizeof(outbuf) - (cp - outbuf), actual_format, ap);

    /*
     * Now that we have the message formatted, perform the output to each
     * logging specification.
     */
    for (lindex = 0; lindex < log_control.log_nentries; lindex++) {
        switch (log_control.log_entries[lindex].log_type) {
        case K_LOG_FILE:
        case K_LOG_STDERR:
            /*
             * Files/standard error.
             */
            if (fprintf(log_control.log_entries[lindex].lfu_filep, "%s\n",
                        outbuf) < 0) {
                /* Attempt to report error */
                fprintf(stderr, log_file_err, whoami,
                        log_control.log_entries[lindex].lfu_fname);
            }
            else {
                fflush(log_control.log_entries[lindex].lfu_filep);
            }
            break;
        case K_LOG_CONSOLE:
        case K_LOG_DEVICE:
            /*
             * Devices (may need special handling)
             */
            if (DEVICE_PRINT(log_control.log_entries[lindex].ldu_filep,
                             outbuf) < 0) {
                /* Attempt to report error */
                fprintf(stderr, log_device_err, whoami,
                        log_control.log_entries[lindex].ldu_devname);
            }
            break;
#ifdef  HAVE_SYSLOG
        case K_LOG_SYSLOG:
            /*
             * System log.
             */
            /*
             * If we have specified a priority through our hackery, then
             * use it, otherwise use the default.
             */
            if (log_pri >= 0)
                log_pri |= log_control.log_entries[lindex].lsu_facility;
            else
                log_pri = log_control.log_entries[lindex].lsu_facility |
                    log_control.log_entries[lindex].lsu_severity;

            /* Log the message with our header trimmed off */
            syslog(log_pri, "%s", syslogp);
            break;
#endif /* HAVE_SYSLOG */
        default:
            break;
        }
    }
}

/*
 * krb5_klog_init()     - Initialize logging.
 *
 * This routine parses the syntax described above to specify destinations for
 * com_err(3) or krb5_klog_syslog() messages generated by the caller.
 *
 * Parameters:
 *      kcontext        - Kerberos context.
 *      ename           - Entity name as it is to appear in the profile.
 *      whoami          - Entity name as it is to appear in error output.
 *      do_com_err      - Take over com_err(3) processing.
 *
 * Implicit inputs:
 *      stderr          - This is where STDERR output goes.
 *
 * Implicit outputs:
 *      log_nentries    - Number of log entries, both valid and invalid.
 *      log_control     - List of entries (log_nentries long) which contains
 *                        data for klog_com_err_proc() to use to determine
 *                        where/how to send output.
 */
krb5_error_code
krb5_klog_init(krb5_context kcontext, char *ename, char *whoami, krb5_boolean do_com_err)
{
    const char  *logging_profent[3];
    const char  *logging_defent[3];
    char        **logging_specs;
    int         i, ngood;
    char        *cp, *cp2;
    char        savec = '\0';
    int         error;
    int         do_openlog, log_facility;
    FILE        *f;

    /* Initialize */
    do_openlog = 0;
    log_facility = 0;

    err_context = kcontext;

    /*
     * Look up [logging]-><ename> in the profile.  If that doesn't
     * succeed, then look for [logging]->default.
     */
    logging_profent[0] = KRB5_CONF_LOGGING;
    logging_profent[1] = ename;
    logging_profent[2] = (char *) NULL;
    logging_defent[0] = KRB5_CONF_LOGGING;
    logging_defent[1] = KRB5_CONF_DEFAULT;
    logging_defent[2] = (char *) NULL;
    logging_specs = (char **) NULL;
    ngood = 0;
    log_control.log_nentries = 0;
    if (!profile_get_values(kcontext->profile,
                            logging_profent,
                            &logging_specs) ||
        !profile_get_values(kcontext->profile,
                            logging_defent,
                            &logging_specs)) {
        /*
         * We have a match, so we first count the number of elements
         */
        for (log_control.log_nentries = 0;
             logging_specs[log_control.log_nentries];
             log_control.log_nentries++);

        /*
         * Now allocate our structure.
         */
        log_control.log_entries = (struct log_entry *)
            malloc(log_control.log_nentries * sizeof(struct log_entry));
        if (log_control.log_entries) {
            /*
             * Scan through the list.
             */
            for (i=0; i<log_control.log_nentries; i++) {
                log_control.log_entries[i].log_type = K_LOG_NONE;
                log_control.log_entries[i].log_2free = logging_specs[i];
                /*
                 * The format is:
                 *      <whitespace><data><whitespace>
                 * so, trim off the leading and trailing whitespace here.
                 */
                for (cp = logging_specs[i]; isspace((int) *cp); cp++);
                for (cp2 = &logging_specs[i][strlen(logging_specs[i])-1];
                     isspace((int) *cp2); cp2--);
                cp2++;
                *cp2 = '\0';
                /*
                 * Is this a file?
                 */
                if (!strncasecmp(cp, "FILE", 4)) {
                    /*
                     * Check for append/overwrite, then open the file.
                     */
                    if (cp[4] == ':' || cp[4] == '=') {
                        f = fopen(&cp[5], (cp[4] == ':') ? "a" : "w");
                        if (f) {
                            set_cloexec_file(f);
                            log_control.log_entries[i].lfu_filep = f;
                            log_control.log_entries[i].log_type = K_LOG_FILE;
                            log_control.log_entries[i].lfu_fname = &cp[5];
                        } else {
                            fprintf(stderr,"Couldn't open log file %s: %s\n",
                                    &cp[5], error_message(errno));
                            continue;
                        }
                    }
                }
#ifdef  HAVE_SYSLOG
                /*
                 * Is this a syslog?
                 */
                else if (!strncasecmp(cp, "SYSLOG", 6)) {
                    error = 0;
                    log_control.log_entries[i].lsu_facility = LOG_AUTH;
                    log_control.log_entries[i].lsu_severity = LOG_ERR;
                    /*
                     * Is there a severify specified?
                     */
                    if (cp[6] == ':') {
                        /*
                         * Find the end of the severity.
                         */
                        cp2 = strchr(&cp[7], ':');
                        if (cp2) {
                            savec = *cp2;
                            *cp2 = '\0';
                            cp2++;
                        }

                        /*
                         * Match a severity.
                         */
                        if (!strcasecmp(&cp[7], "ERR")) {
                            log_control.log_entries[i].lsu_severity = LOG_ERR;
                        }
#ifdef  LOG_EMERG
                        else if (!strcasecmp(&cp[7], "EMERG")) {
                            log_control.log_entries[i].lsu_severity =
                                LOG_EMERG;
                        }
#endif  /* LOG_EMERG */
#ifdef  LOG_ALERT
                        else if (!strcasecmp(&cp[7], "ALERT")) {
                            log_control.log_entries[i].lsu_severity =
                                LOG_ALERT;
                        }
#endif  /* LOG_ALERT */
#ifdef  LOG_CRIT
                        else if (!strcasecmp(&cp[7], "CRIT")) {
                            log_control.log_entries[i].lsu_severity = LOG_CRIT;
                        }
#endif  /* LOG_CRIT */
#ifdef  LOG_WARNING
                        else if (!strcasecmp(&cp[7], "WARNING")) {
                            log_control.log_entries[i].lsu_severity =
                                LOG_WARNING;
                        }
#endif  /* LOG_WARNING */
#ifdef  LOG_NOTICE
                        else if (!strcasecmp(&cp[7], "NOTICE")) {
                            log_control.log_entries[i].lsu_severity =
                                LOG_NOTICE;
                        }
#endif  /* LOG_NOTICE */
#ifdef  LOG_INFO
                        else if (!strcasecmp(&cp[7], "INFO")) {
                            log_control.log_entries[i].lsu_severity = LOG_INFO;
                        }
#endif  /* LOG_INFO */
#ifdef  LOG_DEBUG
                        else if (!strcasecmp(&cp[7], "DEBUG")) {
                            log_control.log_entries[i].lsu_severity =
                                LOG_DEBUG;
                        }
#endif  /* LOG_DEBUG */
                        else
                            error = 1;

                        /*
                         * If there is a facility present, then parse that.
                         */
                        if (cp2) {
                            static const struct {
                                const char *name;
                                int value;
                            } facilities[] = {
                                { "AUTH",       LOG_AUTH        },
#ifdef  LOG_AUTHPRIV
                                { "AUTHPRIV",   LOG_AUTHPRIV    },
#endif  /* LOG_AUTHPRIV */
#ifdef  LOG_KERN
                                { "KERN",       LOG_KERN        },
#endif  /* LOG_KERN */
#ifdef  LOG_USER
                                { "USER",       LOG_USER        },
#endif  /* LOG_USER */
#ifdef  LOG_MAIL
                                { "MAIL",       LOG_MAIL        },
#endif  /* LOG_MAIL */
#ifdef  LOG_DAEMON
                                { "DAEMON",     LOG_DAEMON      },
#endif  /* LOG_DAEMON */
#ifdef  LOG_FTP
                                { "FTP",        LOG_FTP         },
#endif  /* LOG_FTP */
#ifdef  LOG_LPR
                                { "LPR",        LOG_LPR         },
#endif  /* LOG_LPR */
#ifdef  LOG_NEWS
                                { "NEWS",       LOG_NEWS        },
#endif  /* LOG_NEWS */
#ifdef  LOG_UUCP
                                { "UUCP",       LOG_UUCP        },
#endif  /* LOG_UUCP */
#ifdef  LOG_CRON
                                { "CRON",       LOG_CRON        },
#endif  /* LOG_CRON */
#ifdef  LOG_LOCAL0
                                { "LOCAL0",     LOG_LOCAL0      },
#endif  /* LOG_LOCAL0 */
#ifdef  LOG_LOCAL1
                                { "LOCAL1",     LOG_LOCAL1      },
#endif  /* LOG_LOCAL1 */
#ifdef  LOG_LOCAL2
                                { "LOCAL2",     LOG_LOCAL2      },
#endif  /* LOG_LOCAL2 */
#ifdef  LOG_LOCAL3
                                { "LOCAL3",     LOG_LOCAL3      },
#endif  /* LOG_LOCAL3 */
#ifdef  LOG_LOCAL4
                                { "LOCAL4",     LOG_LOCAL4      },
#endif  /* LOG_LOCAL4 */
#ifdef  LOG_LOCAL5
                                { "LOCAL5",     LOG_LOCAL5      },
#endif  /* LOG_LOCAL5 */
#ifdef  LOG_LOCAL6
                                { "LOCAL6",     LOG_LOCAL6      },
#endif  /* LOG_LOCAL6 */
#ifdef  LOG_LOCAL7
                                { "LOCAL7",     LOG_LOCAL7      },
#endif  /* LOG_LOCAL7 */
                            };
                            unsigned int j;

                            for (j = 0; j < sizeof(facilities)/sizeof(facilities[0]); j++)
                                if (!strcasecmp(cp2, facilities[j].name)) {
                                    log_control.log_entries[i].lsu_facility = facilities[j].value;
                                    break;
                                }
                            cp2--;
                            *cp2 = savec;
                        }
                    }
                    if (!error) {
                        log_control.log_entries[i].log_type = K_LOG_SYSLOG;
                        do_openlog = 1;
                        log_facility = log_control.log_entries[i].lsu_facility;
                    }
                }
#endif  /* HAVE_SYSLOG */
                /*
                 * Is this a standard error specification?
                 */
                else if (!strcasecmp(cp, "STDERR")) {
                    log_control.log_entries[i].lfu_filep =
                        fdopen(fileno(stderr), "a+");
                    if (log_control.log_entries[i].lfu_filep) {
                        log_control.log_entries[i].log_type = K_LOG_STDERR;
                        log_control.log_entries[i].lfu_fname =
                            "standard error";
                    }
                }
                /*
                 * Is this a specification of the console?
                 */
                else if (!strcasecmp(cp, "CONSOLE")) {
                    log_control.log_entries[i].ldu_filep =
                        CONSOLE_OPEN("a+");
                    if (log_control.log_entries[i].ldu_filep) {
                        set_cloexec_file(log_control.log_entries[i].ldu_filep);
                        log_control.log_entries[i].log_type = K_LOG_CONSOLE;
                        log_control.log_entries[i].ldu_devname = "console";
                    }
                }
                /*
                 * Is this a specification of a device?
                 */
                else if (!strncasecmp(cp, "DEVICE", 6)) {
                    /*
                     * We handle devices very similarly to files.
                     */
                    if (cp[6] == '=') {
                        log_control.log_entries[i].ldu_filep =
                            DEVICE_OPEN(&cp[7], "w");
                        if (log_control.log_entries[i].ldu_filep) {
                            set_cloexec_file(log_control.log_entries[i].ldu_filep);
                            log_control.log_entries[i].log_type = K_LOG_DEVICE;
                            log_control.log_entries[i].ldu_devname = &cp[7];
                        }
                    }
                }
                /*
                 * See if we successfully parsed this specification.
                 */
                if (log_control.log_entries[i].log_type == K_LOG_NONE) {
                    fprintf(stderr, lspec_parse_err_1, whoami, cp);
                    fprintf(stderr, lspec_parse_err_2, whoami);
                }
                else
                    ngood++;
            }
        }
        /*
         * If we didn't find anything, then free our lists.
         */
        if (ngood == 0) {
            for (i=0; i<log_control.log_nentries; i++)
                free(logging_specs[i]);
        }
        free(logging_specs);
    }
    /*
     * If we didn't find anything, go for the default which is to log to
     * the system log.
     */
    if (ngood == 0) {
        if (log_control.log_entries)
            free(log_control.log_entries);
        log_control.log_entries = &def_log_entry;
        log_control.log_entries->log_type = K_LOG_SYSLOG;
        log_control.log_entries->log_2free = (krb5_pointer) NULL;
        log_facility = log_control.log_entries->lsu_facility = LOG_AUTH;
        log_control.log_entries->lsu_severity = LOG_ERR;
        do_openlog = 1;
        log_control.log_nentries = 1;
    }
    if (log_control.log_nentries) {
        log_control.log_whoami = strdup(whoami);
        log_control.log_hostname = (char *) malloc(MAXHOSTNAMELEN + 1);
        if (log_control.log_hostname) {
            if (gethostname(log_control.log_hostname, MAXHOSTNAMELEN) == -1) {
                free(log_control.log_hostname);
                log_control.log_hostname = NULL;
            } else
                log_control.log_hostname[MAXHOSTNAMELEN] = '\0';
        }
#ifdef  HAVE_OPENLOG
        if (do_openlog) {
            openlog(whoami, LOG_NDELAY|LOG_PID, log_facility);
            log_control.log_opened = 1;
        }
#endif /* HAVE_OPENLOG */
        if (do_com_err)
            (void) set_com_err_hook(klog_com_err_proc);
    }
    return((log_control.log_nentries) ? 0 : ENOENT);
}

/*
 * krb5_klog_close()    - Close the logging context and free all data.
 */
void
krb5_klog_close(krb5_context kcontext)
{
    int lindex;
    (void) reset_com_err_hook();
    for (lindex = 0; lindex < log_control.log_nentries; lindex++) {
        switch (log_control.log_entries[lindex].log_type) {
        case K_LOG_FILE:
        case K_LOG_STDERR:
            /*
             * Files/standard error.
             */
            fclose(log_control.log_entries[lindex].lfu_filep);
            break;
        case K_LOG_CONSOLE:
        case K_LOG_DEVICE:
            /*
             * Devices (may need special handling)
             */
            DEVICE_CLOSE(log_control.log_entries[lindex].ldu_filep);
            break;
#ifdef  HAVE_SYSLOG
        case K_LOG_SYSLOG:
            /*
             * System log.
             */
            break;
#endif  /* HAVE_SYSLOG */
        default:
            break;
        }
        if (log_control.log_entries[lindex].log_2free)
            free(log_control.log_entries[lindex].log_2free);
    }
    if (log_control.log_entries != &def_log_entry)
        free(log_control.log_entries);
    log_control.log_entries = (struct log_entry *) NULL;
    log_control.log_nentries = 0;
    if (log_control.log_whoami)
        free(log_control.log_whoami);
    log_control.log_whoami = (char *) NULL;
    if (log_control.log_hostname)
        free(log_control.log_hostname);
    log_control.log_hostname = (char *) NULL;
#ifdef  HAVE_CLOSELOG
    if (log_control.log_opened)
        closelog();
#endif  /* HAVE_CLOSELOG */
}

/*
 * severity2string()    - Convert a severity to a string.
 */
static const char *
severity2string(int severity)
{
    int s;
    const char *ss;

    s = severity & LOG_PRIMASK;
    ss = log_ufo_string;
    switch (s) {
#ifdef  LOG_EMERG
    case LOG_EMERG:
        ss = log_emerg_string;
        break;
#endif  /* LOG_EMERG */
#ifdef  LOG_ALERT
    case LOG_ALERT:
        ss = log_alert_string;
        break;
#endif  /* LOG_ALERT */
#ifdef  LOG_CRIT
    case LOG_CRIT:
        ss = log_crit_string;
        break;
#endif  /* LOG_CRIT */
    case LOG_ERR:
        ss = log_err_string;
        break;
#ifdef  LOG_WARNING
    case LOG_WARNING:
        ss = log_warning_string;
        break;
#endif  /* LOG_WARNING */
#ifdef  LOG_NOTICE
    case LOG_NOTICE:
        ss = log_notice_string;
        break;
#endif  /* LOG_NOTICE */
#ifdef  LOG_INFO
    case LOG_INFO:
        ss = log_info_string;
        break;
#endif  /* LOG_INFO */
#ifdef  LOG_DEBUG
    case LOG_DEBUG:
        ss = log_debug_string;
        break;
#endif  /* LOG_DEBUG */
    }
    return(ss);
}

/*
 * krb5_klog_syslog()   - Simulate the calling sequence of syslog(3), while
 *                        also performing the logging redirection as specified
 *                        by krb5_klog_init().
 */
static int
klog_vsyslog(int priority, const char *format, va_list arglist)
#if !defined(__cplusplus) && (__GNUC__ > 2)
    __attribute__((__format__(__printf__, 2, 0)))
#endif
    ;

static int
klog_vsyslog(int priority, const char *format, va_list arglist)
{
    char        outbuf[KRB5_KLOG_MAX_ERRMSG_SIZE];
    int         lindex;
    char        *syslogp;
    char        *cp;
    time_t      now;
#ifdef  HAVE_STRFTIME
    size_t      soff;
#endif  /* HAVE_STRFTIME */

    /*
     * Format a syslog-esque message of the format:
     *
     * (verbose form)
     *          <date> <hostname> <id>[<pid>](<priority>): <message>
     *
     * (short form)
     *          <date> <message>
     */
    cp = outbuf;
    (void) time(&now);
#ifdef  HAVE_STRFTIME
    /*
     * Format the date: mon dd hh:mm:ss
     */
    soff = strftime(outbuf, sizeof(outbuf), "%b %d %H:%M:%S", localtime(&now));
    if (soff > 0)
        cp += soff;
    else
        return(-1);
#else   /* HAVE_STRFTIME */
    /*
     * Format the date:
     * We ASSUME here that the output of ctime is of the format:
     *  dow mon dd hh:mm:ss tzs yyyy\n
     *  012345678901234567890123456789
     */
    strncpy(outbuf, ctime(&now) + 4, 15);
    cp += 15;
#endif  /* HAVE_STRFTIME */
#ifdef VERBOSE_LOGS
    snprintf(cp, sizeof(outbuf) - (cp-outbuf), " %s %s[%ld](%s): ",
             log_control.log_hostname ? log_control.log_hostname : "",
             log_control.log_whoami ? log_control.log_whoami : "",
             (long) getpid(),
             severity2string(priority));
#else
    snprintf(cp, sizeof(outbuf) - (cp-outbuf), " ");
#endif
    syslogp = &outbuf[strlen(outbuf)];

    /* Now format the actual message */
    vsnprintf(syslogp, sizeof(outbuf) - (syslogp - outbuf), format, arglist);

    /*
     * If the user did not use krb5_klog_init() instead of dropping
     * the request on the floor, syslog it - if it exists
     */
#ifdef HAVE_SYSLOG
    if (log_control.log_nentries == 0) {
        /* Log the message with our header trimmed off */
        syslog(priority, "%s", syslogp);
    }
#endif

    /*
     * Now that we have the message formatted, perform the output to each
     * logging specification.
     */
    for (lindex = 0; lindex < log_control.log_nentries; lindex++) {
        switch (log_control.log_entries[lindex].log_type) {
        case K_LOG_FILE:
        case K_LOG_STDERR:
            /*
             * Files/standard error.
             */
            if (fprintf(log_control.log_entries[lindex].lfu_filep, "%s\n",
                        outbuf) < 0) {
                /* Attempt to report error */
                fprintf(stderr, log_file_err, log_control.log_whoami,
                        log_control.log_entries[lindex].lfu_fname);
            }
            else {
                fflush(log_control.log_entries[lindex].lfu_filep);
            }
            break;
        case K_LOG_CONSOLE:
        case K_LOG_DEVICE:
            /*
             * Devices (may need special handling)
             */
            if (DEVICE_PRINT(log_control.log_entries[lindex].ldu_filep,
                             outbuf) < 0) {
                /* Attempt to report error */
                fprintf(stderr, log_device_err, log_control.log_whoami,
                        log_control.log_entries[lindex].ldu_devname);
            }
            break;
#ifdef  HAVE_SYSLOG
        case K_LOG_SYSLOG:
            /*
             * System log.
             */

            /* Log the message with our header trimmed off */
            syslog(priority, "%s", syslogp);
            break;
#endif /* HAVE_SYSLOG */
        default:
            break;
        }
    }
    return(0);
}

int
krb5_klog_syslog(int priority, const char *format, ...)
{
    int         retval;
    va_list     pvar;

    va_start(pvar, format);
    retval = klog_vsyslog(priority, format, pvar);
    va_end(pvar);
    return(retval);
}

/*
 * krb5_klog_reopen() - Close and reopen any open (non-syslog) log files.
 *                      This function is called when a SIGHUP is received
 *                      so that external log-archival utilities may
 *                      alert the Kerberos daemons that they should get
 *                      a new file descriptor for the give filename.
 */
void
krb5_klog_reopen(krb5_context kcontext)
{
    int lindex;
    FILE *f;

    /*
     * Only logs which are actually files need to be closed
     * and reopened in response to a SIGHUP
     */
    for (lindex = 0; lindex < log_control.log_nentries; lindex++) {
        if (log_control.log_entries[lindex].log_type == K_LOG_FILE) {
            fclose(log_control.log_entries[lindex].lfu_filep);
            /*
             * In case the old logfile did not get moved out of the
             * way, open for append to prevent squashing the old logs.
             */
            f = fopen(log_control.log_entries[lindex].lfu_fname, "a+");
            if (f) {
                set_cloexec_file(f);
                log_control.log_entries[lindex].lfu_filep = f;
            } else {
                fprintf(stderr, "Couldn't open log file %s: %s\n",
                        log_control.log_entries[lindex].lfu_fname,
                        error_message(errno));
            }
        }
    }
}