/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2019 Joyent, Inc.
 *
 * logadm/main.c -- main routines for logadm
 *
 * this program is 90% argument processing, 10% actions...
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <libintl.h>
#include <locale.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/filio.h>
#include <sys/sysmacros.h>
#include <time.h>
#include <utime.h>
#include <poll.h>
#include <errno.h>
#include "err.h"
#include "lut.h"
#include "fn.h"
#include "opts.h"
#include "conf.h"
#include "glob.h"
#include "kw.h"

/* forward declarations for functions in this file */
static void usage(const char *msg);
static void commajoin(const char *lhs, void *rhs, void *arg);
static void doaftercmd(const char *lhs, void *rhs, void *arg);
static void dologname(struct fn *fnp, struct opts *clopts);
static boolean_t rotatelog(struct fn *fnp, struct opts *opts);
static void rotateto(struct fn *fnp, struct opts *opts, int n,
    struct fn *recentlog, boolean_t isgz);
static void do_delayed_gzip(const char *lhs, void *rhs, void *arg);
static void expirefiles(struct fn *fnp, struct opts *opts);
static void dorm(struct opts *opts, const char *msg, struct fn *fnp);
static void docmd(struct opts *opts, const char *msg, const char *cmd,
    const char *arg1, const char *arg2, const char *arg3);
static void docopytruncate(struct opts *opts, const char *file,
    const char *file_copy);

/* our configuration file, unless otherwise specified by -f */
static char *Default_conffile = "/etc/logadm.conf";
/* our timestamps file, unless otherwise specified by -F */
static char *Default_timestamps = "/var/logadm/timestamps";

/* default pathnames to the commands we invoke */
static char *Sh = "/bin/sh";
static char *Mv = "/bin/mv";
static char *Rm = "/bin/rm";
static char *Touch = "/bin/touch";
static char *Chmod = "/bin/chmod";
static char *Chown = "/bin/chown";
static char *Gzip = "/bin/gzip";
static char *Mkdir = "/bin/mkdir";

int Debug;

/* return from time(0), gathered early on to avoid slewed timestamps */
time_t Now;

/* list of before commands that have been executed */
static struct lut *Beforecmds;

/* list of after commands to execute before exiting */
static struct lut *Aftercmds;

/* list of conffile entry names that are considered "done" */
static struct lut *Donenames;

/* A list of names of files to be gzipped */
static struct lut *Gzipnames = NULL;

/*
 * only the "FfhnVv" options are allowed in the first form of this command,
 * so this defines the list of options that are an error in they appear
 * in the first form.  In other words, it is not allowed to run logadm
 * with any of these options unless at least one logname is also provided.
 */
#define OPTIONS_NOT_FIRST_FORM  "eNrwpPsabcglmoRtzACEST"

/* text that we spew with the -h flag */
#define HELP1 \
"Usage: logadm [options]\n"\
"       (processes all entries in /etc/logadm.conf or conffile given by -f)\n"\
"   or: logadm [options] logname...\n"\
"       (processes the given lognames)\n"\
"\n"\
"General options:\n"\
"        -e mailaddr     mail errors to given address\n"\
"        -F timestamps   use timestamps instead of /var/logadm/timestamps\n"\
"        -f conffile     use conffile instead of /etc/logadm.conf\n"\
"        -h              display help\n"\
"        -N              not an error if log file nonexistent\n"\
"        -n              show actions, don't perform them\n"\
"        -r              remove logname entry from conffile\n"\
"        -V              ensure conffile entries exist, correct\n"\
"        -v              print info about actions happening\n"\
"        -w entryname    write entry to config file\n"\
"\n"\
"Options which control when a logfile is rotated:\n"\
"(default is: -s1b -p1w if no -s or -p)\n"\
"        -p period       only rotate if period passed since last rotate\n"\
"        -P timestamp    used to store rotation date in conffile\n"\
"        -s size         only rotate if given size or greater\n"\
"\n"
#define HELP2 \
"Options which control how a logfile is rotated:\n"\
"(default is: -t '$file.$n', owner/group/mode taken from log file)\n"\
"        -a cmd          execute cmd after taking actions\n"\
"        -b cmd          execute cmd before taking actions\n"\
"        -c              copy & truncate logfile, don't rename\n"\
"        -g group        new empty log file group\n"\
"        -l              rotate log file with local time rather than UTC\n"\
"        -m mode         new empty log file mode\n"\
"        -M cmd          execute cmd to rotate the log file\n"\
"        -o owner        new empty log file owner\n"\
"        -R cmd          run cmd on file after rotate\n"\
"        -t template     template for naming old logs\n"\
"        -z count        gzip old logs except most recent count\n"\
"\n"\
"Options which control the expiration of old logfiles:\n"\
"(default is: -C10 if no -A, -C, or -S)\n"\
"        -A age          expire logs older than age\n"\
"        -C count        expire old logs until count remain\n"\
"        -E cmd          run cmd on file to expire\n"\
"        -S size         expire until space used is below size \n"\
"        -T pattern      pattern for finding old logs\n"

/*
 * main -- where it all begins
 */
/*ARGSUSED*/
int
main(int argc, char *argv[])
{
        struct opts *clopts = NULL;     /* from parsing command line */
        const char *conffile;           /* our configuration file */
        const char *timestamps;         /* our timestamps file */
        struct fn_list *lognames;       /* list of lognames we're processing */
        struct fn *fnp;
        char *val;
        char *buf;
        int status;

        (void) setlocale(LC_ALL, "");

#if !defined(TEXT_DOMAIN)
#define TEXT_DOMAIN "SYS_TEST"  /* only used if Makefiles don't define it */
#endif

        (void) textdomain(TEXT_DOMAIN);

        /* we only print times into the timestamps file, so make them uniform */
        (void) setlocale(LC_TIME, "C");

        /* give our name to error routines & skip it for arg parsing */
        err_init(*argv++);
        (void) setlinebuf(stdout);

        if (putenv("PATH=/bin"))
                err(EF_SYS, "putenv PATH");
        if (putenv("TZ=UTC"))
                err(EF_SYS, "putenv TZ");
        tzset();

        (void) umask(0);

        Now = time(0);

        /* check for (undocumented) debugging environment variables */
        if (val = getenv("_LOGADM_DEFAULT_CONFFILE"))
                Default_conffile = val;
        if (val = getenv("_LOGADM_DEFAULT_TIMESTAMPS"))
                Default_timestamps = val;
        if (val = getenv("_LOGADM_DEBUG"))
                Debug = atoi(val);
        if (val = getenv("_LOGADM_SH"))
                Sh = val;
        if (val = getenv("_LOGADM_MV"))
                Mv = val;
        if (val = getenv("_LOGADM_RM"))
                Rm = val;
        if (val = getenv("_LOGADM_TOUCH"))
                Touch = val;
        if (val = getenv("_LOGADM_CHMOD"))
                Chmod = val;
        if (val = getenv("_LOGADM_CHOWN"))
                Chown = val;
        if (val = getenv("_LOGADM_GZIP"))
                Gzip = val;
        if (val = getenv("_LOGADM_MKDIR"))
                Mkdir = val;

        opts_init(Opttable, Opttable_cnt);

        /* parse command line arguments */
        if (SETJMP)
                usage("bailing out due to command line errors");
        else
                clopts = opts_parse(NULL, argv, OPTF_CLI);

        if (Debug) {
                (void) fprintf(stderr, "command line opts:");
                opts_print(clopts, stderr, NULL);
                (void) fprintf(stderr, "\n");
        }

        /*
         * There are many moods of logadm:
         *
         *      1. "-h" for help was given.  We spew a canned help
         *         message and exit, regardless of any other options given.
         *
         *      2. "-r" or "-w" asking us to write to the conffile.  Lots
         *         of argument checking, then we make the change to conffile
         *         and exit.  (-r processing actually happens in dologname().)
         *
         *      3. "-V" to search/verify the conffile was given.  We do
         *         the appropriate run through the conffile and exit.
         *         (-V processing actually happens in dologname().)
         *
         *      4. No lognames were given, so we're being asked to go through
         *         every entry in conffile.  We verify that only the options
         *         that make sense for this form of the command are present
         *         and fall into the main processing loop below.
         *
         *      5. lognames were given, so we fall into the main processing
         *         loop below to work our way through them.
         *
         * The last two cases are where the option processing gets more
         * complex.  Each time around the main processing loop, we're
         * in one of these cases:
         *
         *      A. No cmdargs were found (we're in case 4), the entry
         *         in conffile supplies no log file names, so the entry
         *         name itself is the logfile name (or names, if it globs
         *         to multiple file names).
         *
         *      B. No cmdargs were found (we're in case 4), the entry
         *         in conffile gives log file names that we then loop
         *         through and rotate/expire.  In this case, the entry
         *         name is specifically NOT one of the log file names.
         *
         *      C. We're going through the cmdargs (we're in case 5),
         *         the entry in conffile either doesn't exist or it exists
         *         but supplies no log file names, so the cmdarg itself
         *         is the log file name.
         *
         *      D. We're going through the cmdargs (we're in case 5),
         *         a matching entry in conffile supplies log file names
         *         that we then loop through and rotate/expire.  In this
         *         case the entry name is specifically NOT one of the log
         *         file names.
         *
         * As we're doing all this, any options given on the command line
         * override any found in the conffile, and we apply the defaults
         * for rotation conditions and expiration conditions, etc. at the
         * last opportunity, when we're sure they haven't been overridden
         * by an option somewhere along the way.
         *
         */

        /* help option overrides anything else */
        if (opts_count(clopts, "h")) {
                (void) fputs(HELP1, stderr);
                (void) fputs(HELP2, stderr);
                err_done(0);
                /*NOTREACHED*/
        }

        /* detect illegal option combinations */
        if (opts_count(clopts, "rwV") > 1)
                usage("Only one of -r, -w, or -V may be used at a time.");
        if (opts_count(clopts, "cM") > 1)
                usage("Only one of -c or -M may be used at a time.");

        /* arrange for error output to be mailed if clopts includes -e */
        if (opts_count(clopts, "e"))
                err_mailto(opts_optarg(clopts, "e"));

        /* this implements the default conffile and timestamps */
        if ((conffile = opts_optarg(clopts, "f")) == NULL)
                conffile = Default_conffile;
        if ((timestamps = opts_optarg(clopts, "F")) == NULL)
                timestamps = Default_timestamps;
        if (opts_count(clopts, "v"))
                (void) out("# loading %s\n", conffile);
        status = conf_open(conffile, timestamps, clopts);
        if (!status && opts_count(clopts, "V"))
                err_done(0);

        /* handle conffile write option */
        if (opts_count(clopts, "w")) {
                if (Debug)
                        (void) fprintf(stderr,
                            "main: add/replace conffile entry: <%s>\n",
                            opts_optarg(clopts, "w"));
                conf_replace(opts_optarg(clopts, "w"), clopts);
                conf_close(clopts);
                err_done(0);
                /*NOTREACHED*/
        }

        /*
         * lognames is either a list supplied on the command line,
         * or every entry in the conffile if none were supplied.
         */
        lognames = opts_cmdargs(clopts);
        if (fn_list_empty(lognames)) {
                /*
                 * being asked to do all entries in conffile
                 *
                 * check to see if any options were given that only
                 * make sense when lognames are given specifically
                 * on the command line.
                 */
                if (opts_count(clopts, OPTIONS_NOT_FIRST_FORM))
                        usage("some options require logname argument");
                if (Debug)
                        (void) fprintf(stderr,
                            "main: run all entries in conffile\n");
                lognames = conf_entries();
        }

        /* foreach logname... */
        fn_list_rewind(lognames);
        while ((fnp = fn_list_next(lognames)) != NULL) {
                buf = fn_s(fnp);
                if (buf != NULL && lut_lookup(Donenames, buf) != NULL) {
                        if (Debug)
                                (void) fprintf(stderr,
                                    "main: logname already done: <%s>\n",
                                    buf);
                        continue;
                }
                if (buf != NULL && SETJMP)
                        err(EF_FILE, "bailing out on logname \"%s\" "
                            "due to errors", buf);
                else
                        dologname(fnp, clopts);
        }

        /* execute any after commands */
        lut_walk(Aftercmds, doaftercmd, clopts);

        /* execute any gzip commands */
        lut_walk(Gzipnames, do_delayed_gzip, clopts);

        /* write out any conffile changes */
        conf_close(clopts);

        err_done(0);
        /*NOTREACHED*/
        return (0);     /* for lint's little mind */
}

/* spew a message, then a usage message, then exit */
static void
usage(const char *msg)
{
        if (msg)
                err(0, "%s\nUse \"logadm -h\" for help.", msg);
        else
                err(EF_RAW, "Use \"logadm -h\" for help.\n");
}

/* helper function used by doaftercmd() to join mail addrs with commas */
/*ARGSUSED1*/
static void
commajoin(const char *lhs, void *rhs, void *arg)
{
        struct fn *fnp = (struct fn *)arg;
        char *buf;

        buf = fn_s(fnp);
        if (buf != NULL && *buf)
                fn_putc(fnp, ',');
        fn_puts(fnp, lhs);
}

/* helper function used by main() to run "after" commands */
static void
doaftercmd(const char *lhs, void *rhs, void *arg)
{
        struct opts *opts = (struct opts *)arg;
        struct lut *addrs = (struct lut *)rhs;

        if (addrs) {
                struct fn *fnp = fn_new(NULL);

                /*
                 * addrs contains list of email addrs that should get
                 * the error output when this after command is executed.
                 */
                lut_walk(addrs, commajoin, fnp);
                err_mailto(fn_s(fnp));
        }

        docmd(opts, "-a cmd", Sh, "-c", lhs, NULL);
}

/* perform delayed gzip */

static void
do_delayed_gzip(const char *lhs, void *rhs, void *arg)
{
        struct opts *opts = (struct opts *)arg;

        if (rhs == NULL) {
                if (Debug) {
                        (void) fprintf(stderr, "do_delayed_gzip: not gzipping "
                            "expired file <%s>\n", lhs);
                }
                return;
        }
        docmd(opts, "compress old log (-z flag)", Gzip, "-f", lhs, NULL);
}


/* main logname processing */
static void
dologname(struct fn *fnp, struct opts *clopts)
{
        const char *logname = fn_s(fnp);
        struct opts *cfopts;
        struct opts *allopts;
        struct fn_list *logfiles;
        struct fn_list *globbedfiles;
        struct fn *nextfnp;

        /* look up options set by config file */
        cfopts = conf_opts(logname);

        if (opts_count(clopts, "v"))
                (void) out("# processing logname: %s\n", logname);

        if (Debug) {
                if (logname != NULL)
                        (void) fprintf(stderr, "dologname: logname <%s>\n",
                            logname);
                (void) fprintf(stderr, "conffile opts:");
                opts_print(cfopts, stderr, NULL);
                (void) fprintf(stderr, "\n");
        }

        /* handle conffile lookup option */
        if (opts_count(clopts, "V")) {
                /* lookup an entry in conffile */
                if (Debug)
                        (void) fprintf(stderr,
                            "dologname: lookup conffile entry\n");
                if (conf_lookup(logname)) {
                        opts_printword(logname, stdout);
                        opts_print(cfopts, stdout, NULL);
                        (void) out("\n");
                } else
                        err_exitcode(1);
                return;
        }

        /* handle conffile removal option */
        if (opts_count(clopts, "r")) {
                if (Debug)
                        (void) fprintf(stderr,
                            "dologname: remove conffile entry\n");
                if (conf_lookup(logname))
                        conf_replace(logname, NULL);
                else
                        err_exitcode(1);
                return;
        }

        /* generate combined options */
        allopts = opts_merge(cfopts, clopts);

        /* arrange for error output to be mailed if allopts includes -e */
        if (opts_count(allopts, "e"))
                err_mailto(opts_optarg(allopts, "e"));
        else
                err_mailto(NULL);

        /* this implements the default rotation rules */
        if (opts_count(allopts, "sp") == 0) {
                if (opts_count(clopts, "v"))
                        (void) out(
                            "#     using default rotate rules: -s1b -p1w\n");
                (void) opts_set(allopts, "s", "1b");
                (void) opts_set(allopts, "p", "1w");
        }

        /* this implements the default expiration rules */
        if (opts_count(allopts, "ACS") == 0) {
                if (opts_count(clopts, "v"))
                        (void) out("#     using default expire rule: -C10\n");
                (void) opts_set(allopts, "C", "10");
        }

        /* this implements the default template */
        if (opts_count(allopts, "t") == 0) {
                if (opts_count(clopts, "v"))
                        (void) out("#     using default template: $file.$n\n");
                (void) opts_set(allopts, "t", "$file.$n");
        }

        if (Debug) {
                (void) fprintf(stderr, "merged opts:");
                opts_print(allopts, stderr, NULL);
                (void) fprintf(stderr, "\n");
        }

        /*
         * if the conffile entry supplied log file names, then
         * logname is NOT one of the log file names (it was just
         * the entry name in conffile).
         */
        logfiles = opts_cmdargs(cfopts);
        if (Debug) {
                char *buf;
                (void) fprintf(stderr, "dologname: logfiles from cfopts:\n");
                fn_list_rewind(logfiles);
                while ((nextfnp = fn_list_next(logfiles)) != NULL) {
                        buf = fn_s(nextfnp);
                        if (buf != NULL)
                                (void) fprintf(stderr, "    <%s>\n", buf);
                }
        }
        if (fn_list_empty(logfiles))
                globbedfiles = glob_glob(fnp);
        else
                globbedfiles = glob_glob_list(logfiles);

        /* go through the list produced by glob expansion */
        fn_list_rewind(globbedfiles);
        while ((nextfnp = fn_list_next(globbedfiles)) != NULL)
                if (rotatelog(nextfnp, allopts))
                        expirefiles(nextfnp, allopts);

        fn_list_free(globbedfiles);
        opts_free(allopts);
}


/* absurdly long buffer lengths for holding user/group/mode strings */
#define TIMESTRMAX      100
#define MAXATTR         100

/* rotate a log file if necessary, returns true if ok to go on to expire step */
static boolean_t
rotatelog(struct fn *fnp, struct opts *opts)
{
        char *fname = fn_s(fnp);
        struct stat stbuf;
        char nowstr[TIMESTRMAX];
        struct fn *recentlog = fn_new(NULL);    /* for -R cmd */
        char ownerbuf[MAXATTR];
        char groupbuf[MAXATTR];
        char modebuf[MAXATTR];
        const char *owner;
        const char *group;
        const char *mode;

        if (Debug && fname != NULL)
                (void) fprintf(stderr, "rotatelog: fname <%s>\n", fname);

        if (opts_count(opts, "p") && opts_optarg_int(opts, "p") == OPTP_NEVER)
                return (B_TRUE);        /* "-p never" forced no rotate */

        /* prepare the keywords */
        kw_init(fnp, NULL);
        if (Debug > 1) {
                (void) fprintf(stderr, "rotatelog keywords:\n");
                kw_print(stderr);
        }

        if (lstat(fname, &stbuf) < 0) {
                if (opts_count(opts, "N"))
                        return (1);
                err(EF_WARN|EF_SYS, "%s", fname);
                return (B_FALSE);
        }

        if ((stbuf.st_mode & S_IFMT) == S_IFLNK) {
                err(EF_WARN, "%s is a symlink", fname);
                return (B_FALSE);
        }

        if ((stbuf.st_mode & S_IFMT) != S_IFREG) {
                err(EF_WARN, "%s is not a regular file", fname);
                return (B_FALSE);
        }

        /* even if size condition is not met, this entry is "done" */
        if (opts_count(opts, "s") &&
            stbuf.st_size < opts_optarg_int(opts, "s")) {
                Donenames = lut_add(Donenames, fname, "1");
                return (B_TRUE);
        }

        /* see if age condition is present, and return if not met */
        if (opts_count(opts, "p")) {
                off_t when = opts_optarg_int(opts, "p");
                struct opts *cfopts;

                /* unless rotate forced by "-p now", see if period has passed */
                if (when != OPTP_NOW) {
                        /*
                         * "when" holds the number of seconds that must have
                         * passed since the last time this log was rotated.
                         * of course, running logadm can take a little time
                         * (typically a second or two, but longer if the
                         * conffile has lots of stuff in it) and that amount
                         * of time is variable, depending on system load, etc.
                         * so we want to allow a little "slop" in the value of
                         * "when".  this way, if a log should be rotated every
                         * week, and the number of seconds passed is really a
                         * few seconds short of a week, we'll go ahead and
                         * rotate the log as expected.
                         *
                         */
                        if (when >= 60 * 60)
                                when -= 59;

                        /*
                         * last rotation is recorded as argument to -P,
                         * but if logname isn't the same as log file name
                         * then the timestamp would be recorded on a
                         * separate line in the timestamp file.  so if we
                         * haven't seen a -P already, we check to see if
                         * it is part of a specific entry for the log
                         * file name.  this handles the case where the
                         * logname is "apache", it supplies a log file
                         * name like "/var/apache/logs/[a-z]*_log",
                         * which expands to multiple file names.  if one
                         * of the file names is "/var/apache/logs/access_log"
                         * the the -P will be attached to a line with that
                         * logname in the timestamp file.
                         */
                        if (opts_count(opts, "P")) {
                                off_t last = opts_optarg_int(opts, "P");

                                /* return if not enough time has passed */
                                if (Now - last < when)
                                        return (B_TRUE);
                        } else if ((cfopts = conf_opts(fname)) != NULL &&
                            opts_count(cfopts, "P")) {
                                off_t last = opts_optarg_int(cfopts, "P");

                                /*
                                 * just checking this means this entry
                                 * is now "done" if we're going through
                                 * the entire conffile
                                 */
                                Donenames = lut_add(Donenames, fname, "1");

                                /* return if not enough time has passed */
                                if (Now - last < when)
                                        return (B_TRUE);
                        }
                }
        }

        if (Debug)
                (void) fprintf(stderr, "rotatelog: conditions met\n");
        if (opts_count(opts, "l")) {
                /* Change the time zone to local time zone */
                if (putenv("TZ="))
                        err(EF_SYS, "putenv TZ");
                tzset();
                Now = time(0);

                /* rename the log file */
                rotateto(fnp, opts, 0, recentlog, B_FALSE);

                /* Change the time zone to UTC */
                if (putenv("TZ=UTC"))
                        err(EF_SYS, "putenv TZ");
                tzset();
                Now = time(0);
        } else {
                /* rename the log file */
                rotateto(fnp, opts, 0, recentlog, B_FALSE);
        }

        /* determine owner, group, mode for empty log file */
        if (opts_count(opts, "o"))
                (void) strlcpy(ownerbuf, opts_optarg(opts, "o"), MAXATTR);
        else {
                (void) snprintf(ownerbuf, MAXATTR, "%ld", stbuf.st_uid);
        }
        owner = ownerbuf;
        if (opts_count(opts, "g"))
                group = opts_optarg(opts, "g");
        else {
                (void) snprintf(groupbuf, MAXATTR, "%ld", stbuf.st_gid);
                group = groupbuf;
        }
        (void) strlcat(ownerbuf, ":", MAXATTR - strlen(ownerbuf));
        (void) strlcat(ownerbuf, group, MAXATTR - strlen(ownerbuf));
        if (opts_count(opts, "m"))
                mode = opts_optarg(opts, "m");
        else {
                (void) snprintf(modebuf, MAXATTR,
                    "%03lo", stbuf.st_mode & 0777);
                mode = modebuf;
        }

        /* create the empty log file */
        docmd(opts, NULL, Touch, fname, NULL, NULL);
        docmd(opts, NULL, Chown, owner, fname, NULL);
        docmd(opts, NULL, Chmod, mode, fname, NULL);

        /* execute post-rotation command */
        if (opts_count(opts, "R")) {
                struct fn *rawcmd = fn_new(opts_optarg(opts, "R"));
                struct fn *cmd = fn_new(NULL);

                kw_init(recentlog, NULL);
                (void) kw_expand(rawcmd, cmd, 0, B_FALSE);
                docmd(opts, "-R cmd", Sh, "-c", fn_s(cmd), NULL);
                fn_free(rawcmd);
                fn_free(cmd);
        }
        fn_free(recentlog);

        /*
         * add "after" command to list of after commands.  we also record
         * the email address, if any, where the error output of the after
         * command should be sent.  if the after command is already on
         * our list, add the email addr to the list the email addrs for
         * that command (the after command will only be executed once,
         * so the error output gets mailed to every address we've come
         * across associated with this command).
         */
        if (opts_count(opts, "a")) {
                const char *cmd = opts_optarg(opts, "a");
                struct lut *addrs = (struct lut *)lut_lookup(Aftercmds, cmd);
                if (opts_count(opts, "e"))
                        addrs = lut_add(addrs, opts_optarg(opts, "e"), NULL);
                Aftercmds = lut_add(Aftercmds, opts_optarg(opts, "a"), addrs);
        }

        /* record the rotation date */
        (void) strftime(nowstr, sizeof (nowstr),
            "%a %b %e %T %Y", gmtime(&Now));
        if (opts_count(opts, "v") && fname != NULL)
                (void) out("#     recording rotation date %s for %s\n",
                    nowstr, fname);
        conf_set(fname, "P", STRDUP(nowstr));
        Donenames = lut_add(Donenames, fname, "1");
        return (B_TRUE);
}

/* rotate files "up" according to current template */
static void
rotateto(struct fn *fnp, struct opts *opts, int n, struct fn *recentlog,
    boolean_t isgz)
{
        struct fn *template = fn_new(opts_optarg(opts, "t"));
        struct fn *newfile = fn_new(NULL);
        struct fn *dirname;
        int hasn;
        struct stat stbuf;
        char *buf1;
        char *buf2;

        /* expand template to figure out new filename */
        hasn = kw_expand(template, newfile, n, isgz);

        buf1 = fn_s(fnp);
        buf2 = fn_s(newfile);

        if (Debug)
                if (buf1 != NULL && buf2 != NULL) {
                        (void) fprintf(stderr, "rotateto: %s -> %s (%d)\n",
                            buf1, buf2, n);
                }
        /* if filename is there already, rotate "up" */
        if (hasn && lstat(buf2, &stbuf) != -1)
                rotateto(newfile, opts, n + 1, recentlog, isgz);
        else if (hasn && opts_count(opts, "z")) {
                struct fn *gzfnp = fn_dup(newfile);
                /*
                 * since we're compressing old files, see if we
                 * about to rotate into one.
                 */
                fn_puts(gzfnp, ".gz");
                if (lstat(fn_s(gzfnp), &stbuf) != -1)
                        rotateto(gzfnp, opts, n + 1, recentlog, B_TRUE);
                fn_free(gzfnp);
        }

        /* first time through run "before" cmd if not run already */
        if (n == 0 && opts_count(opts, "b")) {
                const char *cmd = opts_optarg(opts, "b");

                if (lut_lookup(Beforecmds, cmd) == NULL) {
                        docmd(opts, "-b cmd", Sh, "-c", cmd, NULL);
                        Beforecmds = lut_add(Beforecmds, cmd, "1");
                }
        }

        /* ensure destination directory exists */
        dirname = fn_dirname(newfile);
        docmd(opts, "verify directory exists", Mkdir, "-p",
            fn_s(dirname), NULL);
        fn_free(dirname);

        /* do the rename */
        if (n == 0 && opts_count(opts, "c") != 0) {
                docopytruncate(opts, fn_s(fnp), fn_s(newfile));
        } else if (n == 0 && opts_count(opts, "M")) {
                struct fn *rawcmd = fn_new(opts_optarg(opts, "M"));
                struct fn *cmd = fn_new(NULL);

                /* use specified command to mv the log file */
                kw_init(fnp, newfile);
                (void) kw_expand(rawcmd, cmd, 0, B_FALSE);
                docmd(opts, "-M cmd", Sh, "-c", fn_s(cmd), NULL);
                fn_free(rawcmd);
                fn_free(cmd);
        } else
                /* common case: we call "mv" to handle the actual rename */
                docmd(opts, "rotate log file", Mv, "-f",
                    fn_s(fnp), fn_s(newfile));

        /* first time through, gather interesting info for caller */
        if (n == 0)
                fn_renew(recentlog, fn_s(newfile));
}

/* expire phase of logname processing */
static void
expirefiles(struct fn *fnp, struct opts *opts)
{
        char *fname = fn_s(fnp);
        struct fn *template;
        struct fn *pattern;
        struct fn_list *files;
        struct fn *nextfnp;
        off_t count;
        off_t size;

        if (Debug && fname != NULL)
                (void) fprintf(stderr, "expirefiles: fname <%s>\n", fname);

        /* return if no potential expire conditions */
        if (opts_count(opts, "zAS") == 0 && opts_optarg_int(opts, "C") == 0)
                return;

        kw_init(fnp, NULL);
        if (Debug > 1) {
                (void) fprintf(stderr, "expirefiles keywords:\n");
                kw_print(stderr);
        }

        /* see if pattern was supplied by user */
        if (opts_count(opts, "T")) {
                template = fn_new(opts_optarg(opts, "T"));
                pattern = glob_to_reglob(template);
        } else {
                /* nope, generate pattern based on rotation template */
                template = fn_new(opts_optarg(opts, "t"));
                pattern = fn_new(NULL);
                (void) kw_expand(template, pattern, -1,
                    opts_count(opts, "z") != 0);
        }

        /* match all old log files (hopefully not any others as well!) */
        files = glob_reglob(pattern);

        if (Debug) {
                char *buf;

                buf = fn_s(pattern);
                if (buf != NULL) {
                        (void) fprintf(stderr, "expirefiles: pattern <%s>\n",
                            buf);
                }
                fn_list_rewind(files);
                while ((nextfnp = fn_list_next(files)) != NULL) {
                        buf = fn_s(nextfnp);
                        if (buf != NULL)
                                (void) fprintf(stderr, "    <%s>\n", buf);
                }
        }

        /* see if count causes expiration */
        if ((count = opts_optarg_int(opts, "C")) > 0) {
                int needexpire = fn_list_count(files) - count;

                if (Debug)
                        (void) fprintf(stderr, "expirefiles: needexpire %d\n",
                            needexpire);

                while (needexpire > 0 &&
                    ((nextfnp = fn_list_popoldest(files)) != NULL)) {
                        dorm(opts, "expire by count rule", nextfnp);
                        fn_free(nextfnp);
                        needexpire--;
                }
        }

        /* see if total size causes expiration */
        if (opts_count(opts, "S") && (size = opts_optarg_int(opts, "S")) > 0) {
                while (fn_list_totalsize(files) > size &&
                    ((nextfnp = fn_list_popoldest(files)) != NULL)) {
                        dorm(opts, "expire by size rule", nextfnp);
                        fn_free(nextfnp);
                }
        }

        /* see if age causes expiration */
        if (opts_count(opts, "A")) {
                int mtime = (int)time(0) - (int)opts_optarg_int(opts, "A");

                while ((nextfnp = fn_list_popoldest(files)) != NULL) {
                        if (fn_getstat(nextfnp)->st_mtime < mtime) {
                                dorm(opts, "expire by age rule", nextfnp);
                                fn_free(nextfnp);
                        } else {
                                fn_list_addfn(files, nextfnp);
                                break;
                        }
                }
        }

        /* record old log files to be gzip'ed according to -z count */
        if (opts_count(opts, "z")) {
                int zcount = (int)opts_optarg_int(opts, "z");
                int fcount = fn_list_count(files);

                while (fcount > zcount &&
                    (nextfnp = fn_list_popoldest(files)) != NULL) {
                        if (!fn_isgz(nextfnp)) {
                                /*
                                 * Don't gzip the old log file yet -
                                 * it takes too long. Just remember that we
                                 * need to gzip.
                                 */
                                if (Debug) {
                                        (void) fprintf(stderr,
                                            "will compress %s count %d\n",
                                            fn_s(nextfnp), fcount);
                                }
                                Gzipnames = lut_add(Gzipnames,
                                    fn_s(nextfnp), "1");
                        }
                        fn_free(nextfnp);
                        fcount--;
                }
        }

        fn_free(template);
        fn_list_free(files);
}

/* execute a command to remove an expired log file */
static void
dorm(struct opts *opts, const char *msg, struct fn *fnp)
{
        if (opts_count(opts, "E")) {
                struct fn *rawcmd = fn_new(opts_optarg(opts, "E"));
                struct fn *cmd = fn_new(NULL);

                /* user supplied cmd, expand $file */
                kw_init(fnp, NULL);
                (void) kw_expand(rawcmd, cmd, 0, B_FALSE);
                docmd(opts, msg, Sh, "-c", fn_s(cmd), NULL);
                fn_free(rawcmd);
                fn_free(cmd);
        } else
                docmd(opts, msg, Rm, "-f", fn_s(fnp), NULL);
        Gzipnames = lut_add(Gzipnames, fn_s(fnp), NULL);
}

/* execute a command, producing -n and -v output as necessary */
static void
docmd(struct opts *opts, const char *msg, const char *cmd,
    const char *arg1, const char *arg2, const char *arg3)
{
        int pid;
        int errpipe[2];

        /* print info about command if necessary */
        if (opts_count(opts, "vn")) {
                const char *simplecmd;

                if ((simplecmd = strrchr(cmd, '/')) == NULL)
                        simplecmd = cmd;
                else
                        simplecmd++;
                (void) out("%s", simplecmd);
                if (arg1)
                        (void) out(" %s", arg1);
                if (arg2)
                        (void) out(" %s", arg2);
                if (arg3)
                        (void) out(" %s", arg3);
                if (msg)
                        (void) out(" # %s", msg);
                (void) out("\n");
        }

        if (opts_count(opts, "n"))
                return;         /* -n means don't really do it */

        /*
         * Run the cmd and see if it failed.  This function is *not* a generic
         * command runner.  The command name must be an absolute pathname, and
         * two args must be supplied (the second may be NULL, or they may both
         * be NULL).  Any output (stdout and stderr) from the child process is
         * logged to stderr and perhaps sent to an email recipient.
         */
        if (pipe(errpipe) < 0)
                err(EF_SYS, "pipe");

        if ((pid = fork()) < 0)
                err(EF_SYS, "fork");
        else if (pid) {
                int wstat;
                struct pollfd pfd;
                boolean_t first = B_TRUE;

                /* parent */
                (void) close(errpipe[1]);

                pfd.fd = errpipe[0];
                pfd.events = POLLIN | POLLRDNORM | POLLRDBAND | POLLPRI;
                for (;;) {

                        pfd.revents = 0;
                        if (poll(&pfd, 1, -1) == -1) {
                                if (errno == EINTR) {
                                        continue;
                                }
                                err(EF_SYS, "poll");
                                break;
                        }
                        if ((pfd.events & pfd.revents) != 0) {
                                if (first) {
                                        err(EF_WARN,
                                            "command failed: %s%s%s%s%s%s%s",
                                            cmd,
                                            (arg1) ? " " : "",
                                            (arg1) ? arg1 : "",
                                            (arg2) ? " " : "",
                                            (arg2) ? arg2 : "",
                                            (arg3) ? " " : "",
                                            (arg3) ? arg3 : "");
                                        first = B_FALSE;
                                }
                                err_fromfd(pfd.fd);
                        }
                        if ((pfd.revents & (POLLERR | POLLHUP)) != 0) {
                                break;
                        }
                }
                if (waitpid(pid, &wstat, 0) < 0) {
                        err(EF_SYS, "waitpid");
                        return;
                }

                if (!first) {
                        /* Assume the command gave a useful error */
                } else if (WIFSIGNALED(wstat)) {
                        err(EF_WARN,
                            "command died, signal %d: %s%s%s%s%s%s%s",
                            WTERMSIG(wstat),
                            cmd,
                            (arg1) ? " " : "",
                            (arg1) ? arg1 : "",
                            (arg2) ? " " : "",
                            (arg2) ? arg2 : "",
                            (arg3) ? " " : "",
                            (arg3) ? arg3 : "");
                } else if (WIFEXITED(wstat) && WEXITSTATUS(wstat)) {
                        err(EF_WARN,
                            "command error, exit %d: %s%s%s%s%s%s%s",
                            WEXITSTATUS(wstat),
                            cmd,
                            (arg1) ? " " : "",
                            (arg1) ? arg1 : "",
                            (arg2) ? " " : "",
                            (arg2) ? arg2 : "",
                            (arg3) ? " " : "",
                            (arg3) ? arg3 : "");
                }

                (void) close(errpipe[0]);
        } else {
                /* child */
                (void) dup2(errpipe[1], fileno(stderr));
                (void) close(errpipe[0]);
                (void) execl(cmd, cmd, arg1, arg2, arg3, 0);
                perror(cmd);
                _exit(1);
        }
}

/* do internal atomic file copy and truncation */
static void
docopytruncate(struct opts *opts, const char *file, const char *file_copy)
{
        int fi, fo;
        char buf[128 * 1024];
        struct stat s;
        struct utimbuf times;
        off_t written = 0, rem, last = 0, thresh = 1024 * 1024;
        ssize_t len = 0;

        /* print info if necessary */
        if (opts_count(opts, "vn") != 0) {
                (void) out("# log rotation via atomic copy and truncation"
                    " (-c flag):\n");
                (void) out("# copy %s to %s\n", file, file_copy);
                (void) out("# truncate %s\n", file);
        }

        if (opts_count(opts, "n"))
                return;         /* -n means don't really do it */

        /* open log file to be rotated and remember its chmod mask */
        if ((fi = open(file, O_RDWR)) < 0) {
                err(EF_SYS, "cannot open file %s", file);
                return;
        }

        if (fstat(fi, &s) < 0) {
                err(EF_SYS, "cannot access: %s", file);
                (void) close(fi);
                return;
        }

        /* create new file for copy destination with correct attributes */
        if ((fo = open(file_copy, O_CREAT|O_TRUNC|O_WRONLY, s.st_mode)) < 0) {
                err(EF_SYS, "cannot create file: %s", file_copy);
                (void) close(fi);
                return;
        }

        (void) fchown(fo, s.st_uid, s.st_gid);

        /*
         * Now we'll loop, reading the log file and writing it to our copy
         * until the bytes remaining are beneath our atomicity threshold -- at
         * which point we'll lock the file and copy the remainder atomically.
         * The body of this loop is non-atomic with respect to writers, the
         * rationale being that total atomicity (that is, locking the file for
         * the entire duration of the copy) comes at too great a cost for a
         * large log file, as the writer (i.e., the daemon whose log is being
         * rolled) can be blocked for an unacceptable duration.  (For one
         * particularly loquacious daemon, this period was observed to be
         * several minutes in length -- a time so long that it induced
         * additional failures in dependent components.)  Note that this means
         * that if the log file is not always appended to -- if it is opened
         * without O_APPEND or otherwise truncated outside of logadm -- this
         * will result in our log snapshot being incorrect.  But of course, in
         * either of these cases, the use of logadm at all is itself
         * suspect...
         */
        do {
                if (fstat(fi, &s) < 0) {
                        err(EF_SYS, "cannot stat: %s", file);
                        (void) close(fi);
                        (void) close(fo);
                        (void) remove(file_copy);
                        return;
                }

                if ((rem = s.st_size - written) < thresh) {
                        if (rem >= 0)
                                break;

                        /*
                         * If the file became smaller, something fishy is going
                         * on; we'll truncate our copy, reset our seek offset
                         * and break into the atomic copy.
                         */
                        (void) ftruncate(fo, 0);
                        (void) lseek(fo, 0, SEEK_SET);
                        (void) lseek(fi, 0, SEEK_SET);
                        break;
                }

                if (written != 0 && rem > last) {
                        /*
                         * We're falling behind -- this file is getting bigger
                         * faster than we're able to write it; break out and
                         * lock the file to block the writer.
                         */
                        break;
                }

                last = rem;

                while (rem > 0) {
                        if ((len = read(fi, buf, MIN(sizeof (buf), rem))) <= 0)
                                break;

                        if (write(fo, buf, len) == len) {
                                rem -= len;
                                written += len;
                                continue;
                        }

                        err(EF_SYS, "cannot write into file %s", file_copy);
                        (void) close(fi);
                        (void) close(fo);
                        (void) remove(file_copy);
                        return;
                }
        } while (len >= 0);

        /* lock log file so that nobody can write into it before we are done */
        if (fchmod(fi, s.st_mode|S_ISGID) < 0)
                err(EF_SYS, "cannot set mandatory lock bit for: %s", file);

        if (lockf(fi, F_LOCK, 0) == -1)
                err(EF_SYS, "cannot lock file %s", file);

        /* do atomic copy and truncation */
        while ((len = read(fi, buf, sizeof (buf))) > 0)
                if (write(fo, buf, len) != len) {
                        err(EF_SYS, "cannot write into file %s", file_copy);
                        (void) lockf(fi, F_ULOCK, 0);
                        (void) fchmod(fi, s.st_mode);
                        (void) close(fi);
                        (void) close(fo);
                        (void) remove(file_copy);
                        return;
                }

        (void) ftruncate(fi, 0);

        /* unlock log file */
        if (lockf(fi, F_ULOCK, 0) == -1)
                err(EF_SYS, "cannot unlock file %s", file);

        if (fchmod(fi, s.st_mode) < 0)
                err(EF_SYS, "cannot reset mandatory lock bit for: %s", file);

        (void) close(fi);
        (void) close(fo);

        /* keep times from original file */
        times.actime = s.st_atime;
        times.modtime = s.st_mtime;
        (void) utime(file_copy, &times);
}