usr.bin/rdist/server.c

	server.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * Copyright 1998-2003 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 */
#pragma ident   "%Z%%M% %I% %E% SMI"

#include "defs.h"
#include <signal.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#include <ctype.h>
#include <krb5defs.h>

/*
 * If we want to write *to* the client rdist program, *from* the server
 * side (server-side child `rdist -Server' process exec'ed off of in.rshd),
 * we write to stdout/stderr, since there is a pipe connecting stdout/stderr
 * to the outside world (which is why we use `wrem' and not `rem').
 */
int wrem = 1;

#define ack()   (void) write(wrem, "\0\n", 2)
#define err()   (void) write(wrem, "\1\n", 2)

/*
 * Set when a desread() is reqd. in response()
 */

struct  linkbuf *ihead;     /* list of files with more than one link */
char    buf[RDIST_BUFSIZ];  /* general purpose buffer */
char    source[RDIST_BUFSIZ];   /* base source directory name */
char    destination[RDIST_BUFSIZ];  /* base destination directory name */
char    target[RDIST_BUFSIZ];   /* target/source directory name */
char    *tp;            /* pointer to end of target name */
char    *Tdest;         /* pointer to last T dest */
int catname;        /* cat name to target name */
char    *stp[32];       /* stack of saved tp's for directories */
int oumask;         /* old umask for creating files */

extern  FILE *lfp;      /* log file for mailing changes */

void    cleanup();
struct  linkbuf *savelink();
char    *strsub();

/*
 * Server routine to read requests and process them.
 * Commands are:
 *  Tname   - Transmit file if out of date
 *  Vname   - Verify if file out of date or not
 *  Qname   - Query if file exists. Return mtime & size if it does.
 */
server()
{
    char cmdbuf[RDIST_BUFSIZ];
    register char *cp;

    signal(SIGHUP, cleanup);
    signal(SIGINT, cleanup);
    signal(SIGQUIT, cleanup);
    signal(SIGTERM, cleanup);
    signal(SIGPIPE, cleanup);

    rem = 0;
    oumask = umask(0);

    (void) sprintf(buf, "V%d\n", VERSION);
    (void) write(wrem, buf, strlen(buf));

    for (;;) {
        cp = cmdbuf;
        if (read(rem, cp, 1) <= 0)
            return;
        if (*cp++ == '\n') {
            error("server: expected control record\n");
            continue;
        }
        do {
            if (read(rem, cp, 1) != 1)
                cleanup();
        } while (*cp++ != '\n' && cp < &cmdbuf[RDIST_BUFSIZ]);
        *--cp = '\0';
        cp = cmdbuf;
        switch (*cp++) {
        case 'T':  /* init target file/directory name */
            catname = 1;    /* target should be directory */
            goto dotarget;

        case 't':  /* init target file/directory name */
            catname = 0;
        dotarget:
            if (exptilde(target, sizeof (target), cp) == NULL)
                continue;
            tp = target;
            while (*tp)
                tp++;
            ack();
            continue;

        case 'R':  /* Transfer a regular file. */
            recvf(cp, S_IFREG);
            continue;

        case 'D':  /* Transfer a directory. */
            recvf(cp, S_IFDIR);
            continue;

        case 'K':  /* Transfer symbolic link. */
            recvf(cp, S_IFLNK);
            continue;

        case 'k':  /* Transfer hard link. */
            hardlink(cp);
            continue;

        case 'E':  /* End. (of directory) */
            *tp = '\0';
            if (catname <= 0) {
                error("server: too many 'E's\n");
                continue;
            }
            tp = stp[--catname];
            *tp = '\0';
            ack();
            continue;

        case 'C':  /* Clean. Cleanup a directory */
            clean(cp);
            continue;

        case 'Q':  /* Query. Does the file/directory exist? */
            query(cp);
            continue;

        case 'S':  /* Special. Execute commands */
            dospecial(cp);
            continue;

#ifdef notdef
        /*
         * These entries are reserved but not currently used.
         * The intent is to allow remote hosts to have master copies.
         * Currently, only the host rdist runs on can have masters.
         */
        case 'X':  /* start a new list of files to exclude */
            except = bp = NULL;
        case 'x':  /* add name to list of files to exclude */
            if (*cp == '\0') {
                ack();
                continue;
            }
            if (*cp == '~') {
                if (exptilde(buf, sizeof (buf), cp) == NULL)
                    continue;
                cp = buf;
            }
            if (bp == NULL)
                except = bp = expand(makeblock(NAME, cp),
                        E_VARS);
            else
                bp->b_next = expand(makeblock(NAME, cp),
                        E_VARS);
            while (bp->b_next != NULL)
                bp = bp->b_next;
            ack();
            continue;

        case 'I':  /* Install. Transfer file if out of date. */
            opts = 0;
            while (*cp >= '0' && *cp <= '7')
                opts = (opts << 3) | (*cp++ - '0');
            if (*cp++ != ' ') {
                error("server: options not delimited\n");
                return;
            }
            install(cp, opts);
            continue;

        case 'L':  /* Log. save message in log file */
            log(lfp, cp);
            continue;
#endif

        case '\1':
            nerrs++;
            continue;

        case '\2':
            return;

        default:
            error("server: unknown command '%s'\n", cp);
        case '\0':
            continue;
        }
    }
}

/*
 * Update the file(s) if they are different.
 * destdir = 1 if destination should be a directory
 * (i.e., more than one source is being copied to the same destination).
 */
install(src, dest, destdir, opts)
    char *src, *dest;
    int destdir, opts;
{
    char *rname;
    char destcopy[RDIST_BUFSIZ];

    if (dest == NULL) {
        opts &= ~WHOLE; /* WHOLE mode only useful if renaming */
        dest = src;
    }

    if (nflag || debug) {
        printf("%s%s%s%s%s %s %s\n", opts & VERIFY ? "verify":"install",
            opts & WHOLE ? " -w" : "",
            opts & YOUNGER ? " -y" : "",
            opts & COMPARE ? " -b" : "",
            opts & REMOVE ? " -R" : "", src, dest);
        if (nflag)
            return;
    }

    rname = exptilde(target, sizeof (target), src);
    if (rname == NULL)
        return;
    tp = target;
    while (*tp)
        tp++;
    /*
     * If we are renaming a directory and we want to preserve
     * the directory heirarchy (-w), we must strip off the leading
     * directory name and preserve the rest.
     */
    if (opts & WHOLE) {
        while (*rname == '/')
            rname++;
        destdir = 1;
    } else {
        rname = rindex(target, '/');
        if (rname == NULL)
            rname = target;
        else
            rname++;
    }
    if (debug)
        printf("target = %s, rname = %s\n", target, rname);
    /*
     * Pass the destination file/directory name to remote.
     */
    if (snprintf(buf, sizeof (buf), "%c%s\n", destdir ? 'T' : 't', dest) >=
        sizeof (buf)) {
        error("%s: Name too long\n", dest);
        return;
    }
    if (debug)
        printf("buf = %s", buf);
    (void) deswrite(rem, buf, strlen(buf), 0);

    if (response() < 0)
        return;

    strcpy(source, src);
    if (destdir) {
        strcpy(destcopy, dest);
        Tdest = destcopy;
        strcpy(destination, rname);
    } else {
        strcpy(destination, dest);
    }
    sendf(rname, opts);
    Tdest = 0;
}

#define protoname() (pw ? pw->pw_name : user)
#define protogroup()    (gr ? gr->gr_name : group)
/*
 * Transfer the file or directory in target[].
 * rname is the name of the file on the remote host.
 */
sendf(rname, opts)
    char *rname;
    int opts;
{
    register struct subcmd *sc;
    struct stat stb;
    int sizerr, f, u, len;
    off_t i;
    DIR *d;
    struct dirent *dp;
    char *otp, *cp;
    extern struct subcmd *subcmds;
    static char user[15], group[15];

    if (debug)
        printf("sendf(%s, %x%s)\n", rname, opts, printb(opts, OBITS));

    if (except(target))
        return;
    if ((opts & FOLLOW ? stat(target, &stb) : lstat(target, &stb)) < 0) {
        error("%s: %s\n", target, strerror(errno));
        return;
    }
    if (index(rname, '\n')) {
        error("file name '%s' contains an embedded newline - "
            "can't update\n", rname);
        return;
    }
    if ((u = update(rname, opts, &stb)) == 0) {
        if ((stb.st_mode & S_IFMT) == S_IFREG && stb.st_nlink > 1)
            (void) savelink(&stb, opts);
        return;
    }

    if (pw == NULL || pw->pw_uid != stb.st_uid)
        if ((pw = getpwuid(stb.st_uid)) == NULL) {
            log(lfp, "%s: no password entry for uid %d \n",
                target, stb.st_uid);
            pw = NULL;
            sprintf(user, ":%d", stb.st_uid);
        }
    if (gr == NULL || gr->gr_gid != stb.st_gid)
        if ((gr = getgrgid(stb.st_gid)) == NULL) {
            log(lfp, "%s: no name for group %d\n",
                target, stb.st_gid);
            gr = NULL;
            sprintf(group, ":%d", stb.st_gid);
        }
    if (u == 1) {
        if (opts & VERIFY) {
            log(lfp, "need to install: %s\n", target);
            goto dospecial;
        }
        log(lfp, "installing: %s\n", target);
        opts &= ~(COMPARE|REMOVE);
    }

    switch (stb.st_mode & S_IFMT) {
    case S_IFDIR:
        if ((d = opendir(target)) == NULL) {
            error("%s: %s\n", target, strerror(errno));
            return;
        }
        if (snprintf(buf, sizeof (buf), "D%o %04o 0 0 %s %s %s\n",
            opts, stb.st_mode & 07777, protoname(), protogroup(),
            rname) >= sizeof (buf)) {
            error("%s: Name too long\n", rname);
            closedir(d);
            return;
        }
        if (debug)
            printf("buf = %s", buf);
        (void) deswrite(rem, buf, strlen(buf), 0);
        if (response() < 0) {
            closedir(d);
            return;
        }

        if (opts & REMOVE)
            rmchk(opts);

        otp = tp;
        len = tp - target;
        while (dp = readdir(d)) {
            if ((strcmp(dp->d_name, ".") == 0)||
                (strcmp(dp->d_name, "..") == 0))
                continue;
            if ((int)(len + 1 + strlen(dp->d_name)) >=
                (int)(RDIST_BUFSIZ - 1)) {
                error("%.*s/%s: Name too long\n", len, target,
                    dp->d_name);
                continue;
            }
            tp = otp;
            *tp++ = '/';
            cp = dp->d_name;
            while (*tp++ = *cp++)
                ;
            tp--;
            sendf(dp->d_name, opts);
        }
        closedir(d);
        (void) deswrite(rem, "E\n", 2, 0);
        (void) response();
        tp = otp;
        *tp = '\0';
        return;

    case S_IFLNK:
        if (u != 1)
            opts |= COMPARE;
        if (stb.st_nlink > 1) {
            struct linkbuf *lp;

            if ((lp = savelink(&stb, opts)) != NULL) {
                /* install link */
                if (*lp->target == 0)
                    len = snprintf(buf, sizeof (buf),
                        "k%o %s %s\n", opts, lp->pathname,
                        rname);
                else
                    len = snprintf(buf, sizeof (buf),
                        "k%o %s/%s %s\n", opts, lp->target,
                        lp->pathname, rname);
                if (len >= sizeof (buf)) {
                    error("%s: Name too long\n", rname);
                    return;
                }
                if (debug)
                    printf("buf = %s", buf);
                (void) deswrite(rem, buf, strlen(buf), 0);
                (void) response();
                return;
            }
        }
        (void) snprintf(buf, sizeof (buf), "K%o %o %ld %ld %s %s %s\n",
            opts, stb.st_mode & 07777, stb.st_size, stb.st_mtime,
            protoname(), protogroup(), rname);
        if (debug)
            printf("buf = %s", buf);
        (void) deswrite(rem, buf, strlen(buf), 0);
        if (response() < 0)
            return;
        sizerr = (readlink(target, buf, RDIST_BUFSIZ) != stb.st_size);
        (void) deswrite(rem, buf, stb.st_size, 0);
        if (debug)
            printf("readlink = %.*s\n", (int)stb.st_size, buf);
        goto done;

    case S_IFREG:
        break;

    default:
        error("%s: not a file or directory\n", target);
        return;
    }

    if (u == 2) {
        if (opts & VERIFY) {
            log(lfp, "need to update: %s\n", target);
            goto dospecial;
        }
        log(lfp, "updating: %s\n", target);
    }

    if (stb.st_nlink > 1) {
        struct linkbuf *lp;

        if ((lp = savelink(&stb, opts)) != NULL) {
            /* install link */
            if (*lp->target == 0)
                len = snprintf(buf, sizeof (buf), "k%o %s %s\n",
                    opts, lp->pathname, rname);
            else
                len = snprintf(buf, sizeof (buf),
                    "k%o %s/%s %s\n", opts, lp->target,
                    lp->pathname, rname);
            if (len >= sizeof (buf)) {
                error("%s: Name too long\n", rname);
                return;
            }
            if (debug)
                printf("buf = %s", buf);
            (void) deswrite(rem, buf, strlen(buf), 0);
            (void) response();
            return;
        }
    }

    if ((f = open(target, 0)) < 0) {
        error("%s: %s\n", target, strerror(errno));
        return;
    }
    (void) snprintf(buf, sizeof (buf), "R%o %o %ld %ld %s %s %s\n", opts,
        stb.st_mode & 07777, stb.st_size, stb.st_mtime,
        protoname(), protogroup(), rname);
    if (debug)
        printf("buf = %s", buf);
    (void) deswrite(rem, buf, strlen(buf), 0);

    if (response() < 0) {
        (void) close(f);
        return;
    }

    sizerr = 0;

    for (i = 0; i < stb.st_size; i += RDIST_BUFSIZ) {
        int amt = RDIST_BUFSIZ;
        if (i + amt > stb.st_size)
            amt = stb.st_size - i;
        if (sizerr == 0 && read(f, buf, amt) != amt)
            sizerr = 1;
        (void) deswrite(rem, buf, amt, 0);
    }
    (void) close(f);
done:
    if (sizerr) {
        error("%s: file changed size\n", target);
        (void) deswrite(rem, "\1\n", 2, 0);
    } else
        (void) deswrite(rem, "\0\n", 2, 0);
    f = response();

    if (f < 0 || f == 0 && (opts & COMPARE))
        return;
dospecial:
    for (sc = subcmds; sc != NULL; sc = sc->sc_next) {
        if (sc->sc_type != SPECIAL)
            continue;
        if (sc->sc_args != NULL && !inlist(sc->sc_args, target))
            continue;
        log(lfp, "special \"%s\"\n", sc->sc_name);
        if (opts & VERIFY)
            continue;
        (void) snprintf(buf, sizeof (buf), "SFILE=%s;%s\n", target,
            sc->sc_name);
        if (debug)
            printf("buf = %s", buf);
        (void) deswrite(rem, buf, strlen(buf), 0);
        while (response() > 0)
            ;
    }
}

struct linkbuf *
savelink(stp, opts)
    struct stat *stp;
    int opts;
{
    struct linkbuf *lp;

    for (lp = ihead; lp != NULL; lp = lp->nextp)
        if (lp->inum == stp->st_ino && lp->devnum == stp->st_dev) {
            lp->count--;
            return (lp);
        }
    lp = (struct linkbuf *)malloc(sizeof (*lp));
    if (lp == NULL)
        log(lfp, "out of memory, link information lost\n");
    else {
        lp->nextp = ihead;
        ihead = lp;
        lp->inum = stp->st_ino;
        lp->devnum = stp->st_dev;
        lp->count = stp->st_nlink - 1;
        strcpy(lp->pathname,
            opts & WHOLE ?
            target : strsub(source, destination, target));
        if (Tdest)
            strcpy(lp->target, Tdest);
        else
            *lp->target = 0;
    }
    return (NULL);
}

/*
 * Check to see if file needs to be updated on the remote machine.
 * Returns 0 if no update, 1 if remote doesn't exist, 2 if out of date
 * and 3 if comparing binaries to determine if out of date.
 */
update(rname, opts, stp)
    char *rname;
    int opts;
    struct stat *stp;
{
    register char *cp, *s;
    register off_t size;
    register time_t mtime;

    if (debug)
        printf("update(%s, %x%s, %x)\n", rname, opts,
            printb(opts, OBITS), stp);

    /*
     * Check to see if the file exists on the remote machine.
     */
    if (snprintf(buf, sizeof (buf), "Q%s\n", rname) >= sizeof (buf)) {
        error("%s: Name too long\n", rname);
        return (0);
    }
    if (debug)
        printf("buf = %s", buf);
    (void) deswrite(rem, buf, strlen(buf), 0);
again:
    cp = s = buf;
more:
    do {
        if (desread(rem, cp, 1, 0) != 1)
            lostconn();
    } while (*cp++ != '\n' && cp < &buf[RDIST_BUFSIZ]);

    if (cp <  &buf[RDIST_BUFSIZ])
        *cp = '\0';
    if (debug) {
        printf("update reply:  ");
        switch (*s) {
            case 'Y':
            case 'N':
                putchar(*s);
                break;
            default:
                if (iscntrl(*s)) {
                    putchar('^');
                    putchar('A' + *s - 1);
                } else
                    printf("%#x", *s & 0xff);
                break;
        }
        printf("%s", &s[1]);
    }

    switch (*s++) {
    case 'Y':
        break;

    case 'N':  /* file doesn't exist so install it */
        return (1);

    case '\1':
        nerrs++;
        if (*s != '\n') {
            if (!iamremote) {
                fflush(stdout);
                (void) write(2, s, cp - s);
            }
            if (lfp != NULL)
                (void) fwrite(s, 1, cp - s, lfp);
        }
        if (cp == &buf[RDIST_BUFSIZ] && *(cp - 1) != '\n') {
            /* preserve status code */
            cp = s;
            s = buf;
            goto more;
        }
        return (0);

    case '\3':
        *--cp = '\0';
        if (lfp != NULL)
            log(lfp, "update: note: %s\n", s);
        goto again;

    default:
        *--cp = '\0';
        error("update: unexpected response '%s'\n", s);
        return (0);
    }

    if (*s == '\n')
        return (2);

    if (opts & COMPARE)
        return (3);

    size = 0;
    while (isdigit(*s))
        size = size * 10 + (*s++ - '0');
    if (*s++ != ' ') {
        error("update: size not delimited\n");
        return (0);
    }
    mtime = 0;
    while (isdigit(*s))
        mtime = mtime * 10 + (*s++ - '0');
    if (*s != '\n') {
        error("update: mtime not delimited\n");
        return (0);
    }
    /*
     * File needs to be updated?
     */
    if (opts & YOUNGER) {
        if (stp->st_mtime == mtime)
            return (0);
        if (stp->st_mtime < mtime) {
            log(lfp, "Warning: %s: remote copy is newer\n", target);
            return (0);
        }
    } else if (stp->st_mtime == mtime && stp->st_size == size)
        return (0);
    return (2);
}

/*
 * Query. Check to see if file exists. Return one of the following:
 *  N\n     - doesn't exist
 *  Ysize mtime\n   - exists and its a regular file (size & mtime of file)
 *  Y\n     - exists and its a directory or symbolic link
 *  ^Aerror message\n
 */
query(name)
    char *name;
{
    struct stat stb;

    if (catname) {
        if (sizeof (target) - (tp - target) >= strlen(name) + 2) {
            (void) sprintf(tp, "/%s", name);
        } else {
            error("%.*s/%s: Name too long\n", tp - target,
                target, name);
            return;
        }
    }

    if (lstat(target, &stb) < 0) {
        if (errno == ENOENT)
            (void) write(wrem, "N\n", 2);
        else
            error("%s:%s: %s\n", host, target, strerror(errno));
        *tp = '\0';
        return;
    }

    switch (stb.st_mode & S_IFMT) {
    case S_IFREG:
        (void) sprintf(buf, "Y%ld %ld\n", stb.st_size, stb.st_mtime);
        (void) write(wrem, buf, strlen(buf));
        break;

    case S_IFLNK:
    case S_IFDIR:
        (void) write(wrem, "Y\n", 2);
        break;

    default:
        error("%s: not a file or directory\n", name);
        break;
    }
    *tp = '\0';
}

recvf(cmd, type)
    char *cmd;
    int type;
{
    register char *cp;
    int f, mode, opts, wrerr, olderrno;
    off_t i, size;
    time_t mtime;
    struct stat stb;
    struct timeval tvp[2];
    char *owner, *group;
    char new[RDIST_BUFSIZ];
    extern char *tmpname;

    cp = cmd;
    opts = 0;
    while (*cp >= '0' && *cp <= '7')
        opts = (opts << 3) | (*cp++ - '0');
    if (*cp++ != ' ') {
        error("recvf: options not delimited\n");
        return;
    }
    mode = 0;
    while (*cp >= '0' && *cp <= '7')
        mode = (mode << 3) | (*cp++ - '0');
    if (*cp++ != ' ') {
        error("recvf: mode not delimited\n");
        return;
    }
    size = 0;
    while (isdigit(*cp))
        size = size * 10 + (*cp++ - '0');
    if (*cp++ != ' ') {
        error("recvf: size not delimited\n");
        return;
    }
    mtime = 0;
    while (isdigit(*cp))
        mtime = mtime * 10 + (*cp++ - '0');
    if (*cp++ != ' ') {
        error("recvf: mtime not delimited\n");
        return;
    }
    owner = cp;
    while (*cp && *cp != ' ')
        cp++;
    if (*cp != ' ') {
        error("recvf: owner name not delimited\n");
        return;
    }
    *cp++ = '\0';
    group = cp;
    while (*cp && *cp != ' ')
        cp++;
    if (*cp != ' ') {
        error("recvf: group name not delimited\n");
        return;
    }
    *cp++ = '\0';

    if (type == S_IFDIR) {
        int isdot;

        if (strcmp(cp, ".") == 0)
            isdot = 1;
        else
            isdot = 0;
        if (catname >= sizeof (stp) / sizeof (stp[0])) {
            error("%s:%s: too many directory levels\n",
                host, target);
            return;
        }
        stp[catname] = tp;
        if (catname++) {
            *tp++ = '/';
            while (*tp++ = *cp++)
                ;
            tp--;
        }
        if (opts & VERIFY) {
            ack();
            return;
        }
        if (lstat(target, &stb) == 0) {
            if (ISDIR(stb.st_mode)) {
                if ((stb.st_mode & 07777) == mode) {
                    ack();
                    return;
                }
                sendrem("%s: Warning: remote mode %o != "
                    "local mode %o", target,
                    stb.st_mode & 07777, mode);
                return;
            }
            errno = ENOTDIR;
        } else if (errno == ENOENT && (mkdir(target, mode) == 0 ||
            chkparent(target) == 0 &&
            (isdot == 1 || mkdir(target, mode) == 0))) {
            if (chog(target, owner, group, mode) == 0)
                ack();
            return;
        }
        error("%s:%s: %s\n", host, target, strerror(errno));
        tp = stp[--catname];
        *tp = '\0';
        return;
    }

    if (catname) {
        if (sizeof (target) - (tp - target) >= strlen(cp) + 2) {
            (void) sprintf(tp, "/%s", cp);
        } else {
            error("%.*s/%s: Name too long\n", tp - target,
                target, cp);
            return;
        }
    }
    cp = rindex(target, '/');
    if (cp == NULL)
        strcpy(new, tmpname);
    else if (cp == target)
        (void) sprintf(new, "/%s", tmpname);
    else {
        *cp = '\0';
        (void) sprintf(new, "%s/%s", target, tmpname);
        *cp = '/';
    }

    if (type == S_IFLNK) {
        int j;

        ack();
        cp = buf;
        for (i = 0; i < size; i += j) {
            if ((j = read(rem, cp, size - i)) <= 0)
                cleanup();
            cp += j;
        }
        *cp = '\0';
        if (response() < 0) {
            err();
            return;
        }
        if (symlink(buf, new) < 0) {
            if (errno != ENOENT || chkparent(new) < 0 ||
                symlink(buf, new) < 0)
                goto badn;
        }
        mode &= 0777;
        if (opts & COMPARE) {
            char tbuf[MAXPATHLEN];

            if ((i = readlink(target, tbuf, MAXPATHLEN)) >= 0 &&
                i == size && strncmp(buf, tbuf, size) == 0) {
                (void) unlink(new);
                ack();
                return;
            }
            if (opts & VERIFY)
                goto differ;
        }
        goto fixup;
    }

    if ((f = creat(new, mode & ~06000)) < 0) {
        if (errno != ENOENT || chkparent(new) < 0 ||
            (f = creat(new, mode & ~06000)) < 0)
            goto badn;
    }

    ack();
    wrerr = 0;
    for (i = 0; i < size; i += RDIST_BUFSIZ) {
        int amt = RDIST_BUFSIZ;

        cp = buf;
        if (i + amt > size)
            amt = size - i;
        do {
            int j = read(rem, cp, amt);
            if (j <= 0) {
                (void) close(f);
                (void) unlink(new);
                cleanup();
            }
            amt -= j;
            cp += j;
        } while (amt > 0);
        amt = RDIST_BUFSIZ;
        if (i + amt > size)
            amt = size - i;
        if (wrerr == 0 && write(f, buf, amt) != amt) {
            olderrno = errno;
            wrerr++;
        }
    }
    (void) close(f);

    if (response() < 0) {
        err();
        (void) unlink(new);
        return;
    }
    if (wrerr) {
        error("%s:%s: %s\n", host, new, strerror(olderrno));
        (void) unlink(new);
        return;
    }
    if (opts & COMPARE) {
        FILE *f1, *f2;
        int c;

        if ((f1 = fopen(target, "r")) == NULL)
            goto badt;
        if ((f2 = fopen(new, "r")) == NULL) {
        badn:
            error("%s:%s: %s\n", host, new, strerror(errno));
            (void) unlink(new);
            return;
        }
        while ((c = getc(f1)) == getc(f2))
            if (c == EOF) {
                (void) fclose(f1);
                (void) fclose(f2);
                (void) unlink(new);
                ack();
                return;
            }
        (void) fclose(f1);
        (void) fclose(f2);
        if (opts & VERIFY) {
        differ:
            (void) unlink(new);
            sendrem("need to update: %s", target);
            return;
        }
    }

    /*
     * Set last modified time.  For type == S_IFDIR, the lstat above filled
     * in stb.  Otherwise, do it now.
     */
    if (type != S_IFDIR)
        (void) lstat(new, &stb);
    tvp[0].tv_sec = stb.st_atime;   /* old atime from target */
    tvp[0].tv_usec = 0;
    tvp[1].tv_sec = mtime;
    tvp[1].tv_usec = 0;
    if (utimes(new, tvp) < 0) {
        note("%s:utimes failed %s: %s", host, new, strerror(errno));
    }
    if (chog(new, owner, group, mode) < 0) {
        (void) unlink(new);
        return;
    }
fixup:
    if (rename(new, target) < 0) {
badt:
        error("%s:%s: %s\n", host, target, strerror(errno));
        (void) unlink(new);
        return;
    }
    if (opts & COMPARE) {
        sendrem("updated %s", target);
    } else
        ack();
}

/*
 * Creat a hard link to existing file.
 */
hardlink(cmd)
    char *cmd;
{
    register char *cp;
    struct stat stb;
    char *oldname;
    int opts, exists = 0;
    char oldnamebuf[RDIST_BUFSIZ];

    cp = cmd;
    opts = 0;
    while (*cp >= '0' && *cp <= '7')
        opts = (opts << 3) | (*cp++ - '0');
    if (*cp++ != ' ') {
        error("hardlink: options not delimited\n");
        return;
    }
    oldname = cp;
    while (*cp && *cp != ' ')
        cp++;
    if (*cp != ' ') {
        error("hardlink: oldname name not delimited\n");
        return;
    }
    *cp++ = '\0';

    if (catname) {
        if (sizeof (target) - (tp - target) >= strlen(cp) + 2) {
            (void) sprintf(tp, "/%s", cp);
        } else {
            error("%.*s/%s: Name too long\n", tp - target,
                target, cp);
            return;
        }
    }
    if (lstat(target, &stb) == 0) {
        int mode = stb.st_mode & S_IFMT;
        if (mode != S_IFREG && mode != S_IFLNK) {
            error("%s:%s: not a regular file\n", host, target);
            return;
        }
        exists = 1;
    }
    if (chkparent(target) < 0) {
        error("%s:%s: %s (no parent)\n",
            host, target, strerror(errno));
        return;
    }
    if (opts & VERIFY) {
        struct stat nstb;

        if (exists && lstat(oldname, &nstb) == 0 &&
            nstb.st_mode == stb.st_mode &&
            nstb.st_ino == stb.st_ino &&
            nstb.st_dev == stb.st_dev) {
            ack();
            return;
        } else {
            sendrem("need to update: %s", target);
            return;
        }
    }
    if (exists && (unlink(target) < 0)) {
        error("%s:%s: %s (unlink)\n",
            host, target, strerror(errno));
        return;
    }
    if (*oldname == '~')
        oldname = exptilde(oldnamebuf, sizeof (oldnamebuf), oldname);
    if (link(oldname, target) < 0) {
        error("%s:can't link %s to %s\n",
            host, target, oldname);
        return;
    }
    ack();
}

/*
 * Check to see if parent directory exists and create one if not.
 */
chkparent(name)
    char *name;
{
    register char *cp;
    struct stat stb;

    cp = rindex(name, '/');
    if (cp == NULL || cp == name)
        return (0);
    *cp = '\0';
    if (lstat(name, &stb) < 0) {
        if (errno == ENOENT && chkparent(name) >= 0 &&
            mkdir(name, 0777 & ~oumask) >= 0) {
            *cp = '/';
            return (0);
        }
    } else if (ISDIR(stb.st_mode)) {
        *cp = '/';
        return (0);
    }
    *cp = '/';
    return (-1);
}

/*
 * Change owner, group and mode of file.
 */
chog(file, owner, group, mode)
    char *file, *owner, *group;
    int mode;
{
    register int i;
    uid_t uid, gid;
    extern char user[];

    /*
     * by default, set uid of file to the uid of the person running
     * this program.
     */
    uid = getuid();

    /*
     * We'll use available privileges so we just try to do what
     * the client specifies.  If the chown() fails we'll not
     * add the set-[ug]id bits; and if we want to add the set-[ug]id
     * bits and we're not permitted to do so, the OS will prevent us
     * from doing so.
     */
    if (*owner == ':') {
        uid = atoi(owner + 1);
    } else if (pw == NULL || strcmp(owner, pw->pw_name) != 0) {
        if ((pw = getpwnam(owner)) == NULL) {
            if (mode & 04000) {
                note("%s:%s: unknown login name, "
                    "clearing setuid", host, owner);
                mode &= ~04000;
            }
        } else {
            uid = pw->pw_uid;
        }
    } else {
        uid = pw->pw_uid;
    }

    if (*group == ':') {
        gid = atoi(group + 1);
        goto ok;
    }

    gid = -1;
    if (gr == NULL || strcmp(group, gr->gr_name) != 0) {
        if ((*group == ':' &&
            (getgrgid(gid = atoi(group + 1)) == NULL)) ||
            ((gr = getgrnam(group)) == NULL)) {
            if (mode & 02000) {
                note("%s:%s: unknown group", host, group);
                mode &= ~02000;
            }
        } else
            gid = gr->gr_gid;
    } else
        gid = gr->gr_gid;
ok:
    if (chown(file, uid, gid) < 0 ||
        (mode & 07000) && chmod(file, mode) < 0) {
        note("%s: chown or chmod failed: file %s:  %s",
            host, file, strerror(errno));
    }
    return (0);
}

/*
 * Check for files on the machine being updated that are not on the master
 * machine and remove them.
 */
rmchk(opts)
    int opts;
{
    register char *cp, *s;
    struct stat stb;

    if (debug)
        printf("rmchk()\n");

    /*
     * Tell the remote to clean the files from the last directory sent.
     */
    (void) sprintf(buf, "C%o\n", opts & VERIFY);
    if (debug)
        printf("buf = %s", buf);
    (void) deswrite(rem, buf, strlen(buf), 0);
    if (response() < 0)
        return;
    for (;;) {
        cp = s = buf;
        do {
            if (desread(rem, cp, 1, 0) != 1)
                lostconn();
        } while (*cp++ != '\n' && cp < &buf[RDIST_BUFSIZ]);

        switch (*s++) {
        case 'Q': /* Query if file should be removed */
            /*
             * Return the following codes to remove query.
             * N\n -- file exists - DON'T remove.
             * Y\n -- file doesn't exist - REMOVE.
             */
            *--cp = '\0';
            (void) sprintf(tp, "/%s", s);
            if (debug)
                printf("check %s\n", target);
            if (except(target))
                (void) deswrite(rem, "N\n", 2, 0);
            else if (lstat(target, &stb) < 0)
                (void) deswrite(rem, "Y\n", 2, 0);
            else
                (void) deswrite(rem, "N\n", 2, 0);
            break;

        case '\0':
            *--cp = '\0';
            if (*s != '\0')
                log(lfp, "%s\n", s);
            break;

        case 'E':
            *tp = '\0';
            (void) deswrite(rem, "\0\n", 2, 0);
            return;

        case '\1':
        case '\2':
            nerrs++;
            if (*s != '\n') {
                if (!iamremote) {
                    fflush(stdout);
                    (void) write(2, s, cp - s);
                }
                if (lfp != NULL)
                    (void) fwrite(s, 1, cp - s, lfp);
            }
            if (buf[0] == '\2')
                lostconn();
            break;

        default:
            error("rmchk: unexpected response '%s'\n", buf);
            (void) deswrite(rem, "\1\n", 2, 0);
        }
    }
}

/*
 * Check the current directory (initialized by the 'T' command to server())
 * for extraneous files and remove them.
 */
clean(cp)
    register char *cp;
{
    DIR *d;
    register struct dirent *dp;
    struct stat stb;
    char *otp;
    int len, opts;

    opts = 0;
    while (*cp >= '0' && *cp <= '7')
        opts = (opts << 3) | (*cp++ - '0');
    if (*cp != '\0') {
        error("clean: options not delimited\n");
        return;
    }
    if ((d = opendir(target)) == NULL) {
        error("%s:%s: %s\n", host, target, strerror(errno));
        return;
    }
    ack();

    otp = tp;
    len = tp - target;
    while (dp = readdir(d)) {
        if ((strcmp(dp->d_name, ".") == 0) ||
            (strcmp(dp->d_name, "..") == 0))
            continue;
        if ((int)(len + 1 + strlen(dp->d_name)) >=
            (int)(RDIST_BUFSIZ - 1)) {
            error("%s:%s/%s: Name too long\n",
                host, target, dp->d_name);
            continue;
        }
        tp = otp;
        *tp++ = '/';
        cp = dp->d_name;
        while (*tp++ = *cp++)
            ;
        tp--;
        if (lstat(target, &stb) < 0) {
            error("%s:%s: %s\n", host, target, strerror(errno));
            continue;
        }
        (void) snprintf(buf, sizeof (buf), "Q%s\n", dp->d_name);
        (void) write(wrem, buf, strlen(buf));
        cp = buf;
        do {
            if (read(rem, cp, 1) != 1)
                cleanup();
        } while (*cp++ != '\n' && cp < &buf[RDIST_BUFSIZ]);
        *--cp = '\0';
        cp = buf;
        if (*cp != 'Y')
            continue;
        if (opts & VERIFY) {
            sendrem("need to remove: %s", target);
        } else
            (void) recursive_remove(&stb);
    }
    closedir(d);
    (void) write(wrem, "E\n", 2);
    (void) response();
    tp = otp;
    *tp = '\0';
}

/*
 * Remove a file or directory (recursively) and send back an acknowledge
 * or an error message.
 */
static
recursive_remove(stp)
    struct stat *stp;
{
    DIR *d;
    struct dirent *dp;
    register char *cp;
    struct stat stb;
    char *otp;
    int len;

    switch (stp->st_mode & S_IFMT) {
    case S_IFREG:
    case S_IFLNK:
        if (unlink(target) < 0)
            goto bad;
        goto removed;

    case S_IFDIR:
        break;

    default:
        error("%s:%s: not a plain file\n", host, target);
        return;
    }

    if ((d = opendir(target)) == NULL)
        goto bad;

    otp = tp;
    len = tp - target;
    while (dp = readdir(d)) {
        if ((strcmp(dp->d_name, ".") == 0) ||
            (strcmp(dp->d_name, "..") == 0))
            continue;
        if ((int)(len + 1 + strlen(dp->d_name)) >=
            (int)(RDIST_BUFSIZ - 1)) {
            error("%s:%s/%s: Name too long\n",
                host, target, dp->d_name);
            continue;
        }
        tp = otp;
        *tp++ = '/';
        cp = dp->d_name;
        while (*tp++ = *cp++)
            ;
        tp--;
        if (lstat(target, &stb) < 0) {
            error("%s:%s: %s\n", host, target, strerror(errno));
            continue;
        }
        recursive_remove(&stb);
    }
    closedir(d);
    tp = otp;
    *tp = '\0';
    if (rmdir(target) < 0) {
bad:
        error("%s:%s: %s\n", host, target, strerror(errno));
        return;
    }
removed:
    sendrem("removed %s", target);
}

/*
 * Execute a shell command to handle special cases.
 */
dospecial(cmd)
    char *cmd;
{
    int fd[2], status, pid, i;
    register char *cp, *s;
    char sbuf[RDIST_BUFSIZ];

    if (pipe(fd) < 0) {
        error("%s\n", strerror(errno));
        return;
    }
    if ((pid = fork()) == 0) {
        /*
         * Return everything the shell commands print.
         */
        (void) close(0);
        (void) close(1);
        (void) close(2);
        (void) open("/dev/null", 0);
        (void) dup(fd[1]);
        (void) dup(fd[1]);
        (void) close(fd[0]);
        (void) close(fd[1]);
        execl("/bin/sh", "sh", "-c", cmd, 0);
        _exit(127);
    }
    (void) close(fd[1]);
    s = sbuf;
    *s++ = '\0';
    while ((i = read(fd[0], buf, RDIST_BUFSIZ)) > 0) {
        cp = buf;
        do {
            *s++ = *cp++;
            if (cp[-1] != '\n') {
                if (s < &sbuf[RDIST_BUFSIZ - 1])
                    continue;
                *s++ = '\n';
            }
            /*
             * Throw away blank lines.
             */
            if (s == &sbuf[2]) {
                s--;
                continue;
            }
            (void) write(wrem, sbuf, s - sbuf);
            s = &sbuf[1];
        } while (--i);
    }
    if (s > &sbuf[1]) {
        *s++ = '\n';
        (void) write(wrem, sbuf, s - sbuf);
    }
    while ((i = wait(&status)) != pid && i != -1)
        ;
    if (i == -1)
        status = -1;
    (void) close(fd[0]);
    if (status)
        error("shell returned %d\n", status);
    else
        ack();
}

/*VARARGS2*/
log(fp, fmt, a1, a2, a3)
    FILE *fp;
    char *fmt;
    int a1, a2, a3;
{
    /* Print changes locally if not quiet mode */
    if (!qflag)
        printf(fmt, a1, a2, a3);

    /* Save changes (for mailing) if really updating files */
    if (!(options & VERIFY) && fp != NULL)
        fprintf(fp, fmt, a1, a2, a3);
}

/*VARARGS1*/
error(fmt, a1, a2, a3)
    char *fmt;
    int a1, a2, a3;
{
    static FILE *fp;

    nerrs++;
    if (!fp && !(fp = fdopen(rem, "w")))
        return;
    if (iamremote) {
        (void) fprintf(fp, "%crdist: ", 0x01);
        (void) fprintf(fp, fmt, a1, a2, a3);
        fflush(fp);
    } else {
        fflush(stdout);
        (void) fprintf(stderr, "rdist: ");
        (void) fprintf(stderr, fmt, a1, a2, a3);
        fflush(stderr);
    }
    if (lfp != NULL) {
        (void) fprintf(lfp, "rdist: ");
        (void) fprintf(lfp, fmt, a1, a2, a3);
        fflush(lfp);
    }
}

/*VARARGS1*/
fatal(fmt, a1, a2, a3)
    char *fmt;
    int a1, a2, a3;
{
    static FILE *fp;

    nerrs++;
    if (!fp && !(fp = fdopen(rem, "w")))
        return;
    if (iamremote) {
        (void) fprintf(fp, "%crdist: ", 0x02);
        (void) fprintf(fp, fmt, a1, a2, a3);
        fflush(fp);
    } else {
        fflush(stdout);
        (void) fprintf(stderr, "rdist: ");
        (void) fprintf(stderr, fmt, a1, a2, a3);
        fflush(stderr);
    }
    if (lfp != NULL) {
        (void) fprintf(lfp, "rdist: ");
        (void) fprintf(lfp, fmt, a1, a2, a3);
        fflush(lfp);
    }
    cleanup();
}

response()
{
    char *cp, *s;
    char resp[RDIST_BUFSIZ];

    if (debug)
        printf("response()\n");

    cp = s = resp;
more:
    do {
        if (desread(rem, cp, 1, 0) != 1)
            lostconn();
    } while (*cp++ != '\n' && cp < &resp[RDIST_BUFSIZ]);

    switch (*s++) {
    case '\0':
        *--cp = '\0';
        if (*s != '\0') {
            log(lfp, "%s\n", s);
            return (1);
        }
        return (0);
    case '\3':
        *--cp = '\0';
        log(lfp, "Note: %s\n", s);
        return (response());

    default:
        s--;
        /* fall into... */
    case '\1':
    case '\2':
        nerrs++;
        if (*s != '\n') {
            if (!iamremote) {
                fflush(stdout);
                (void) write(2, s, cp - s);
            }
            if (lfp != NULL)
                (void) fwrite(s, 1, cp - s, lfp);
        }
        if (cp == &resp[RDIST_BUFSIZ] && *(cp - 1) != '\n') {
            /* preserve status code */
            cp = s;
            s = resp;
            goto more;
        }
        if (resp[0] == '\2')
            lostconn();
        return (-1);
    }
}

/*
 * Remove temporary files and do any cleanup operations before exiting.
 */
void
cleanup()
{
    (void) unlink(Tmpfile);
    exit(1);
}

note(fmt, a1, a2, a3)
char *fmt;
int a1, a2, a3;
{
    static char buf[RDIST_BUFSIZ];
    (void) snprintf(buf, sizeof (buf) - 1, fmt, a1, a2, a3);
    comment(buf);
}

comment(s)
char *s;
{
    char three = '\3';
    char nl = '\n';
    struct iovec iov[3];

    iov[0].iov_base = &three;
    iov[0].iov_len = sizeof (char);
    iov[1].iov_base = s;
    iov[1].iov_len = strlen(s);
    iov[2].iov_base = &nl;
    iov[2].iov_len = sizeof (char);
    (void) writev(rem, iov, 3);
}

/*
 * Send message to other end.
 * N.B.: uses buf[].
 */
void
sendrem(fmt, a1, a2, a3)
char *fmt;
int a1, a2, a3;
{
    register int len;

    buf[0] = '\0';
    len = snprintf(buf + 1, sizeof (buf) - 1, fmt, a1, a2, a3) + 2;
    if (len > sizeof (buf))
        len = sizeof (buf);
    buf[len - 1] = '\n';
    (void) write(wrem, buf, len);
}

/*
 * strsub(old, new, s)
 *
 * Return a pointer to a new string created by replacing substring old
 * with substring new in string s.  String s is assumed to begin with
 * substring old.
 */
char *
strsub(old, new, s)
    char *old, *new, *s;
{
    static char pbuf[PATH_MAX];
    register char *p, *q, *r, *plim;

    /* prepend new to pbuf */
    for (p = pbuf, q = new, plim = pbuf + sizeof (pbuf) - 1;
    /* CSTYLED */
        *q && (p < plim);)
        *p++ = *q++;
    /* p now points to the byte in pbuf where more copying should begin */

    /* skip over the part of s which begins with old */
    for (r = old, q = s; *r; q++, r++)
        ;
    /* q now points to the byte in s where more copying should begin */

    while (*q && (p < plim))
        *p++ = *q++;
    *p = '\0';

    return (pbuf);
}