/*      $OpenBSD: rmjob.c,v 1.24 2019/07/03 03:24:03 deraadt Exp $      */
/*      $NetBSD: rmjob.c,v 1.16 2000/04/16 14:43:58 mrg Exp $   */

/*
 * Copyright (c) 1983, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <signal.h>
#include <errno.h>
#include <fcntl.h>
#include <dirent.h>
#include <unistd.h>
#include <limits.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include "lp.h"
#include "lp.local.h"
#include "pathnames.h"

/*
 * rmjob - remove the specified jobs from the queue.
 */

/*
 * Stuff for handling lprm specifications
 */
extern char     *user[];                /* users to process */
extern int      users;                  /* # of users in user array */
extern int      requ[];                 /* job number of spool entries */
extern int      requests;               /* # of spool requests */
extern char     *person;                /* name of person doing lprm */

static char     root[] = "root";
static int      all = 0;                /* eliminate all files (root only) */
static int      cur_daemon;             /* daemon's pid */
static char     current[NAME_MAX];      /* active control file name */

static void     alarmer(int);
static int      chk(char *);
static void     do_unlink(char *);
static int      iscf(const struct dirent *);
static int      isowner(char *, char *);
static int      lockchk(char *);
static void     process(char *);
static void     rmremote(void);

void
rmjob(void)
{
        int i, nitems;
        int assassinated = 0;
        struct dirent **files;
        char *cp;

        if ((i = cgetent(&bp, printcapdb, printer)) == -2)
                fatal("can't open printer description file");
        else if (i == -1)
                fatal("unknown printer");
        else if (i == -3)
                fatal("potential reference loop detected in printcap file");
        if (cgetstr(bp, DEFLP, &LP) < 0)
                LP = _PATH_DEFDEVLP;
        if (cgetstr(bp, "rp", &RP) < 0)
                RP = DEFLP;
        if (cgetstr(bp, "sd", &SD) < 0)
                SD = _PATH_DEFSPOOL;
        if (cgetstr(bp,"lo", &LO) < 0)
                LO = DEFLOCK;
        cgetstr(bp, "rm", &RM);
        if ((cp = checkremote()) != NULL)
                printf("Warning: %s\n", cp);

        /*
         * If the format was `lprm -' and the user isn't the super-user,
         *  then fake things to look like he said `lprm user'.
         */
        if (users < 0) {
                if (getuid() == 0)
                        all = 1;        /* all files in local queue */
                else {
                        user[0] = person;
                        users = 1;
                }
        }
        if (!strcmp(person, "-all")) {
                if (from == host)
                        fatal("The login name \"-all\" is reserved");
                all = 1;        /* all those from 'from' */
                person = root;
        }

        PRIV_START;
        if (chdir(SD) < 0)
                fatal("cannot chdir to spool directory");
        if ((nitems = scandir(".", &files, iscf, NULL)) < 0)
                fatal("cannot access spool directory");
        PRIV_END;

        if (nitems) {
                /*
                 * Check for an active printer daemon.  If one is running
                 * and it is reading our file, kill it, then remove stuff.
                 * Lastly, restart the daemon if it is not (or no longer)
                 * running.
                 */
                if (lockchk(LO) && chk(current)) {
                        PRIV_START;
                        assassinated = kill(cur_daemon, SIGINT) == 0;
                        PRIV_END;
                        if (!assassinated)
                                fatal("cannot kill printer daemon");
                }
                /*
                 * process the files
                 */
                for (i = 0; i < nitems; i++)
                        process(files[i]->d_name);
        }
        rmremote();
        /*
         * Restart the printer daemon if it was killed
         */
        if (assassinated && !startdaemon(printer))
                fatal("cannot restart printer daemon");
        exit(0);
}

/*
 * Process a lock file: collect the pid of the active
 * daemon and the file name of the active spool entry.
 * Return boolean indicating existence of a lock file.
 */
static int
lockchk(char *s)
{
        FILE *fp = NULL;
        int fd, i, n;

        /* NOTE: lock file is owned by root, not the user. */
        PRIV_START;
        fd = safe_open(s, O_RDONLY|O_NOFOLLOW, 0);
        PRIV_END;
        if (fd < 0 || (fp = fdopen(fd, "r")) == NULL) {
                if (fd >= 0)
                        close(fd);
                if (errno == EACCES)
                        fatal("can't access lock file");
                else
                        return(0);
        }
        if (!get_line(fp)) {
                (void)fclose(fp);
                return(0);              /* no daemon present */
        }
        cur_daemon = atoi(line);
        if (kill(cur_daemon, 0) < 0 && errno != EPERM) {
                (void)fclose(fp);
                return(0);              /* no daemon present */
        }
        for (i = 1; (n = fread(current, sizeof(char), sizeof(current), fp)) <= 0; i++) {
                if (i > 5) {
                        n = 1;
                        break;
                }
                sleep(i);
        }
        current[n-1] = '\0';
        (void)fclose(fp);
        return(1);
}

/*
 * Process a control file.
 */
static void
process(char *file)
{
        FILE *cfp = NULL;
        int fd;

        if (!chk(file))
                return;
        PRIV_START;
        fd = safe_open(file, O_RDONLY|O_NOFOLLOW, 0);
        PRIV_END;
        if (fd < 0 || (cfp = fdopen(fd, "r")) == NULL) {
                if (fd >= 0)
                        close(fd);
                fatal("cannot open %s", file);
        }
        while (get_line(cfp)) {
                switch (line[0]) {
                case 'U':  /* unlink associated files */
                        if (strchr(line+1, '/') || strncmp(line+1, "df", 2))
                                break;
                        do_unlink(line+1);
                }
        }
        (void)fclose(cfp);
        do_unlink(file);
}

static void
do_unlink(char *file)
{
        int     ret;

        if (from != host)
                printf("%s: ", host);
        PRIV_START;
        ret = unlink(file);
        PRIV_END;
        printf(ret ? "cannot dequeue %s\n" : "%s dequeued\n", file);
}

/*
 * Do the dirty work in checking
 */
static int
chk(char *file)
{
        int *r, n, fd;
        char **u, *cp;
        FILE *cfp = NULL;

        /*
         * Check for valid cf file name (mostly checking current).
         */
        if (strlen(file) < 7 || file[0] != 'c' || file[1] != 'f')
                return(0);

        if (all && (from == host || !strcmp(from, file+6)))
                return(1);

        /*
         * get the owner's name from the control file.
         */
        PRIV_START;
        fd = safe_open(file, O_RDONLY|O_NOFOLLOW, 0);
        PRIV_END;
        if (fd < 0 || (cfp = fdopen(fd, "r")) == NULL) {
                if (fd >= 0)
                        close(fd);
                return(0);
        }
        while (get_line(cfp)) {
                if (line[0] == 'P')
                        break;
        }
        (void)fclose(cfp);
        if (line[0] != 'P')
                return(0);

        if (users == 0 && requests == 0)
                return(!strcmp(file, current) && isowner(line+1, file));
        /*
         * Check the request list
         */
        for (n = 0, cp = file+3; isdigit((unsigned char)*cp); )
                n = n * 10 + (*cp++ - '0');
        for (r = requ; r < &requ[requests]; r++)
                if (*r == n && isowner(line+1, file))
                        return(1);
        /*
         * Check to see if it's in the user list
         */
        for (u = user; u < &user[users]; u++)
                if (!strcmp(*u, line+1) && isowner(line+1, file))
                        return(1);
        return(0);
}

/*
 * If root is removing a file on the local machine, allow it.
 * If root is removing a file from a remote machine, only allow
 * files sent from the remote machine to be removed.
 * Normal users can only remove the file from where it was sent.
 */
static int
isowner(char *owner, char *file)
{
        if (!strcmp(person, root) && (from == host || !strcmp(from, file+6)))
                return(1);
        if (!strcmp(person, owner) && !strcmp(from, file+6))
                return(1);
        if (from != host)
                printf("%s: ", host);
        printf("%s: Permission denied\n", file);
        return(0);
}

/*
 * Check to see if we are sending files to a remote machine. If we are,
 * then try removing files on the remote machine.
 */
static void
rmremote(void)
{
        char *cp;
        int i, rem;
        size_t n;
        char buf[BUFSIZ];

        if (!remote)
                return; /* not sending to a remote machine */

        /*
         * Flush stdout so the user can see what has been deleted
         * while we wait (possibly) for the connection.
         */
        fflush(stdout);

        /* the trailing space will be replaced with a newline later */
        n = snprintf(buf, sizeof(buf), "\5%s %s ", RP, all ? "-all" : person);
        if (n < 0 || n >= sizeof(buf))
                goto bad;
        cp = buf + n;
        for (i = 0; i < users; i++) {
                n = strlcpy(cp, user[i], sizeof(buf) - (cp - buf + 1));
                if (n >= sizeof(buf) - (cp - buf + 1))
                        goto bad;
                cp += n;
                *cp++ = ' ';
        }
        *cp = '\0';
        for (i = 0; i < requests; i++) {
                n = snprintf(cp, sizeof(buf) - (cp - buf), "%d ", requ[i]);
                if (n < 0 || n >= sizeof(buf) - (cp - buf))
                        goto bad;
                cp += n;
        }
        cp[-1] = '\n';          /* replace space with newline, leave the NUL */
        rem = getport(RM, 0);
        if (rem < 0) {
                if (from != host)
                        printf("%s: ", host);
                printf("connection to %s is down\n", RM);
        } else {
                struct sigaction osa, nsa;

                memset(&nsa, 0, sizeof(nsa));
                nsa.sa_handler = alarmer;
                sigemptyset(&nsa.sa_mask);
                nsa.sa_flags = 0;
                (void)sigaction(SIGALRM, &nsa, &osa);
                alarm(wait_time);

                i = strlen(buf);
                if (write(rem, buf, i) != i)
                        fatal("Lost connection");
                while ((i = read(rem, buf, sizeof(buf))) > 0)
                        (void)fwrite(buf, 1, i, stdout);
                alarm(0);
                (void)sigaction(SIGALRM, &osa, NULL);
                (void)close(rem);
        }
        return;
bad:
        printf("remote buffer too large\n");
        return;
}

static void
alarmer(int s)
{
        /* nothing */
}

/*
 * Return 1 if the filename begins with 'cf'
 */
static int
iscf(const struct dirent *d)
{
        return(d->d_name[0] == 'c' && d->d_name[1] == 'f');
}