/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (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 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright (c) 2016 by Delphix. All rights reserved.
 */

/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */


/* Copyright (c) 1981 Regents of the University of California */

#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/fcntl.h>
#include <errno.h>
#include <dirent.h>
#include <pwd.h>
#include <locale.h>
#include <limits.h>
#include <unistd.h>

#define BUFSIZE (LINE_MAX*2)    /* This should agree with what's in ex.h */

#include "ex_tune.h"

#define FTYPE(A)        (A.st_mode)
#define FMODE(A)        (A.st_mode)
#define IDENTICAL(A, B) (A.st_dev == B.st_dev && A.st_ino == B.st_ino)
#define ISBLK(A)        ((A.st_mode & S_IFMT) == S_IFBLK)
#define ISCHR(A)        ((A.st_mode & S_IFMT) == S_IFCHR)
#define ISDIR(A)        ((A.st_mode & S_IFMT) == S_IFDIR)
#define ISFIFO(A)       ((A.st_mode & S_IFMT) == S_IFIFO)
#define ISREG(A)        ((A.st_mode & S_IFMT) == S_IFREG)

/*
 * Expreserve - preserve a file in usrpath(preserve)
 *
 * This routine is very naive - it doesn't remove anything from
 * usrpath(preserve)... this may mean that we  * stuff there...
 * the danger in doing anything with usrpath(preserve)
 * is that the clock may be messed up and we may get confused.
 *
 * We are called in two ways - first from the editor with no arguments
 * and the standard input open on the temp file. Second with an argument
 * to preserve the entire contents of /var/tmp (root only).
 *
 * BUG: should do something about preserving Rx... (register contents)
 *      temporaries.
 */

struct  header {
        time_t  Time;                   /* Time temp file last updated */
        int     Uid;                    /* This user's identity */
#ifndef VMUNIX
        short   Flines;                 /* Number of lines in file */
#else
        int     Flines;
#endif
        unsigned char   Savedfile[FNSIZE];      /* The current file name */
        short   Blocks[LBLKS];          /* Blocks where line pointers stashed */
        short   encrypted;              /* Encrypted temp file flag */
} H;

#define eq(a, b) strcmp(a, b) == 0

void notify(int, unsigned char *, int, int);
void mkdigits(unsigned char *);

int
main(argc)
        int argc;
{
        DIR *tf;
        struct dirent64 *direntry;
        unsigned char *filname;
        struct stat64 stbuf;

        (void) setlocale(LC_ALL, "");
#if !defined(TEXT_DOMAIN)
#define TEXT_DOMAIN "SYS_TEST"
#endif
        (void) textdomain(TEXT_DOMAIN);
        /*
         * If only one argument, then preserve the standard input.
         */
        if (argc == 1) {
                if (copyout((unsigned char *) 0))
                        return (1);
                return (0);
        }

        /*
         * If not super user, then can only preserve standard input.
         */
        if (getuid()) {
                fprintf(stderr, gettext("NOT super user\n"));
                return (1);
        }

        /*
         * ... else preserve all the stuff in /var/tmp, removing
         * it as we go.
         */
        if (chdir(TMPDIR) < 0) {
                perror(TMPDIR);
                return (1);
        }

        if ((tf = opendir(".")) == NULL)
        {
                perror(TMPDIR);
                return (1);
        }
        while ((direntry = readdir64(tf)) != NULL)
        {
                filname = (unsigned char *)direntry->d_name;
                /*
                 * Ex temporaries must begin with Ex;
                 * we check that the 12th character of the name is null
                 * so we won't have to worry about non-null terminated names
                 * later on.
                 */
                if (filname[0] != 'E' || filname[1] != 'x' || filname[12])
                        continue;
                if (stat64((char *)filname, &stbuf))
                        continue;
                if (!ISREG(stbuf))
                        continue;
                /*
                 * Save the file.
                 */
                (void) copyout(filname);
        }
        closedir(tf);
        return (0);
}

unsigned char   mydir[] =       USRPRESERVE;
unsigned char   pattern[] =     "/Exaa`XXXXXXXXXX";

/*
 * Copy file name into usrpath(preserve)/...
 * If name is (char *) 0, then do the standard input.
 * We make some checks on the input to make sure it is
 * really an editor temporary, generate a name for the
 * file (this is the slowest thing since we must stat
 * to find a unique name), and finally copy the file.
 */
int
copyout(unsigned char *name)
{
        int i;
        static int reenter;
        unsigned char buf[BUFSIZE];
        unsigned char   savdir[PATH_MAX+1];
        unsigned char   savfil[PATH_MAX+1];
        struct passwd *pp;
        struct stat64   stbuf;
        int savfild;

        /*
         * The first time we put in the digits of our
         * process number at the end of the pattern.
         */
        if (reenter == 0) {
                mkdigits(pattern);
                reenter++;
        }

        /*
         * If a file name was given, make it the standard
         * input if possible.
         */
        if (name != 0) {
                (void) close(0);
                /*
                 * Need read/write access for arcane reasons
                 * (see below).
                 */
                if (open(name, O_RDWR) < 0)
                        return (-1);
        }

        /*
         * Get the header block.
         */
        (void) lseek(0, 0l, 0);
        if (read(0, (char *)&H, sizeof (H)) != sizeof (H)) {
format:
                if (name == 0)
                        fprintf(stderr, gettext("Buffer format error\t"));
                else {
                        /*
                         * avoid having a bunch of NULL Ex* files
                         * hanging around
                         */
                        struct stat64 stbuf;

                        if (stat64((char *)name, &stbuf) == 0)
                        if (stbuf.st_size == 0)
                                (void) unlink((char *)name);
                }
                return (-1);
        }

        /*
         * Consistency checks so we don't copy out garbage.
         */
        if (H.Flines < 0) {
#ifdef DEBUG
                fprintf(stderr, "Negative number of lines\n");
#endif
                goto format;
        }
        if (H.Blocks[0] != HBLKS || H.Blocks[1] != HBLKS+1) {
#ifdef DEBUG
                fprintf(stderr, "Blocks %d %d\n", H.Blocks[0], H.Blocks[1]);
#endif
                goto format;
        }
        if (name == 0 && H.Uid != getuid()) {
#ifdef DEBUG
                fprintf(stderr, "Wrong user-id\n");
#endif
                goto format;
        }
        if (lseek(0, 0l, 0)) {
#ifdef DEBUG
                fprintf(stderr, gettext("Negative number of lines\n"));
#endif
                goto format;
        }

        /*
         * If no name was assigned to the file, then give it the name
         * LOST, by putting this in the header.
         */
        if (H.Savedfile[0] == 0) {
                (void) strcpy(H.Savedfile, "LOST");
                (void) write(0, (char *) &H, sizeof (H));
                H.Savedfile[0] = 0;
                (void) lseek(0, 0l, 0);
        }

        /*
         * See if preservation directory for user exists.
         */

        strcpy(savdir, mydir);
        pp = getpwuid(H.Uid);
        if (pp)
                strcat(savdir, pp->pw_name);
        else {
                fprintf(stderr, gettext("Unable to get uid for user.\n"));
                return (-1);
        }
        if (lstat64((char *)savdir, &stbuf) < 0 || !S_ISDIR(stbuf.st_mode)) {
                /* It doesn't exist or it isn't a directory, safe to unlink */
                (void) unlink((char *)savdir);
                if (mkdir((char *)savdir, 0700) < 0) {
                        fprintf(stderr,
                                gettext("Unable to create directory \"%s\"\n"),
                                savdir);
                        perror("");
                        return (-1);
                }
                (void) chmod((char *)savdir, 0700);
                (void) chown((char *)savdir, H.Uid, 2);
        }

        /*
         * File is good.  Get a name and create a file for the copy.
         */
        (void) close(1);
        if ((savfild = mknext(savdir, pattern)) < 0) {
                if (name == 0)
                        perror((char *)savfil);
                return  (1);
        }
        strcpy(savfil, savdir);
        strcat(savfil, pattern);
        /*
         * Make target owned by user.
         */

        (void) fchown(savfild, H.Uid, 2);

        /*
         * Copy the file.
         */
        for (;;) {
                i = read(0, buf, BUFSIZE);
                if (i < 0) {
                        if (name)
                                perror(gettext("Buffer read error"));
                        (void) unlink((char *)savfil);
                        return (-1);
                }
                if (i == 0) {
                        if (name)
                                (void) unlink((char *)name);
                        notify(H.Uid, H.Savedfile, (int) name, H.encrypted);
                        return (0);
                }
                if (write(savfild, buf, i) != i) {
                        if (name == 0)
                                perror((char *)savfil);
                        (void) unlink((char *)savfil);
                        return (-1);
                }
        }
}

/*
 * Blast the last 5 characters of cp to be the process number.
 */
void
mkdigits(unsigned char *cp)
{
        pid_t i;
        int j;

        for (i = getpid(), j = 10, cp += strlen(cp); j > 0; i /= 10, j--)
                *--cp = i % 10 | '0';
}

/*
 * Make the name in cp be unique by clobbering up to
 * three alphabetic characters into a sequence of the form 'aab', 'aac', etc.
 * Mktemp gets weird names too quickly to be useful here.
 */
int
mknext(unsigned char *dir, unsigned char *cp)
{
        unsigned char *dcp;
        struct stat stb;
        unsigned char path[PATH_MAX+1];
        int fd;

        strcpy(path, dir);
        strcat(path, cp);
        dcp = path + strlen(path) - 1;

        while (isdigit(*dcp))
                dcp--;

        do {
                if (dcp[0] == 'z') {
                        dcp[0] = 'a';
                        if (dcp[-1] == 'z') {
                                dcp[-1] = 'a';
                                if (dcp[-2] == 'z') {
                                        fprintf(stderr,
                                                gettext("Can't find a name\t"));
                                                return (-1);
                                }
                                dcp[-2]++;
                        } else
                                dcp[-1]++;
                } else
                        dcp[0]++;

        } while (((fd = open(path, O_CREAT|O_EXCL|O_WRONLY, 0600)) < 0) &&
                errno == EEXIST);
        /* copy out patern */
        strcpy(cp, path + strlen(dir));
        return (fd);
}

/*
 * Notify user uid that their file fname has been saved.
 */
void
notify(int uid, unsigned char *fname, int flag, int cryflag)
{

#define MAXHOSTNAMELEN 256

        struct passwd *pp = getpwuid(uid);
        FILE *mf;
        unsigned char cmd[BUFSIZE];

        char hostname[MAXHOSTNAMELEN];
        int namelen = MAXHOSTNAMELEN ;

        if (gethostname((char *)hostname, namelen) == -1)
          return;

        if (pp == NULL)
                return;
        sprintf((char *)cmd, "/usr/bin/mail %s", pp->pw_name);
        mf = popen((char *)cmd, "w");
        if (mf == NULL)
                return;
        setbuf(mf, (char *)cmd);
        if (fname[0] == 0) {
                fprintf(mf, flag ?
"A copy of an editor buffer of yours was saved on %s when the system went down.\n" :
"A copy of an editor buffer of yours was saved on %s when the editor was killed\nor was unable to save your changes.\n", hostname);
                fprintf(mf,
"No name was associated with this buffer so it has been named \"LOST\".\n");
        } else
                fprintf(mf, flag ?
"A copy of an editor buffer of your file \"%s\"%s was saved on %s\nwhen the system \
went down.\n" :
"A copy of an editor buffer of your file \"%s\"%s was saved on %s\nwhen the editor \
was killed or was unable to save your changes.\n", fname, (cryflag) ? "[ENCRYPTED]" : "", hostname);
                /*
                 * "the editor was killed" is perhaps still not an ideal
                 * error message.  Usually, either it was forceably terminated
                 * or the phone was hung up, but we don't know which.
                 */
        fprintf(mf,
"This buffer can be retrieved using the \"recover\" command of the editor.\n");
        fprintf(mf,
"An easy way to do this is to give the command \"vi -r %s\".\n",
                (fname[0] == 0) ? "LOST" : (char *) fname);
        fprintf(mf, "This works for \"edit\" and \"ex\" also.\n");
        (void) pclose(mf);
}