Chip 2001 May/W2KPRK.iso/apps/posix/source/ELVIS/VIREC.C

C/C++ Source or Header | 1999-11-17 | 4.9 KB | 246 lines

/* virec.c */

/* Author:
 *    Steve Kirkendall
 *    14407 SW Teal Blvd. #C
 *    Beaverton, OR 97005
 *    [e-mail]
 */

/* This file contains the file recovery program */


#include "config.h"
#include <stdio.h>
#include <ctype.h>
#include "vi.h"
#if TOS
# include <stat.h>
#else
# if OSK
#  include "osk.h"
# else
#  include <sys/stat.h>
# endif
#endif

extern char    *getenv();
struct stat    stbuf;
BLK        hdr;
BLK        text;

/* the name of the directory where tmp files are stored. */
char o_directory[30] = TMPDIR;

char    *progname;

main(argc, argv)
    int    argc;
    char    **argv;
{
    char    *tmp;
    void recover();
#if MSDOS || TOS
    char **wildexpand();
    argv = wildexpand(&argc, argv);
#endif
    progname = argv[0];
    /* set the o_directory variable */
    if ((tmp = getenv("TMP"))    /* yes, ASSIGNMENT! */
     || (tmp = getenv("TEMP")))    /* yes, ASSIGNMENT! */
    {
        strcpy(o_directory, tmp);
    }
    if (argc >= 3 && !strcmp(argv[1], "-d"))
    {
        strcpy(o_directory, argv[2]);
        argc -= 2;
        argv += 2;
    }
    /* process the arguments */
    if (argc < 2)
    {
        /* maybe stdin comes from a file? */
        if (isatty(0))
        {
            fprintf(stderr, "usage: %s [-d tmpdir] lostfile...\n", progname);
        }
        else if (read(0, &hdr, (unsigned)BLKSIZE) != BLKSIZE)
        {
            fprintf(stderr, "couldn't get header\n");
        }
        else
        {
            copytext(0, stdout);
        }
    }
    else
    {
        while (--argc > 0)
        {
            recover(*++argv);
        }
    }
    exit(0);
}


/* This function recovers a single file */
void recover(filename)
    char    *filename;
{
    char        tmpname[100];
    int        tmpfd;
    FILE        *fp;
    long        mtime;
    int        i, j;
    int        sum;    /* used for calculating a checksum for this */
    char        *scan;

    /* get the file's status info */
    if (stat(filename, &stbuf) < 0)
    {
        /* if serious error, give up on this file */
        if (errno != ENOENT)
        {
            perror(filename);
            return;
        }

        /* else fake it for a new file */
        stat(".", &stbuf);
#if OSK
        stbuf.st_mode = S_IREAD;
#else
        stbuf.st_mode = S_IFREG;
#endif
        stbuf.st_mtime = 0L;
    }

    /* generate a checksum from the file's name */
    for (sum = 0, scan = filename + strlen(filename);
         --scan >= filename && (isascii(*scan) && isalnum(*scan) || *scan == '.');
         sum = sum + *scan)
    {
    }
    sum &= 0xf;

    /* find the tmp file */
#if MSDOS || TOS
    /* MS-Dos doesn't allow multiple slashes, but supports drives
     * with current directories.
     * This relies on TMPNAME beginning with "%s\\"!!!!
     */
    strcpy(tmpname, o_directory);
    if ((i = strlen(tmpname)) && !strchr(":/\\", tmpname[i-1]))
        tmpname[i++]=SLASH;
    sprintf(tmpname+i, TMPNAME+3, sum, stbuf.st_ino, stbuf.st_dev);
#else
    sprintf(tmpname, TMPNAME, o_directory, sum, stbuf.st_ino, stbuf.st_dev);
#endif
    tmpfd = open(tmpname, O_RDONLY | O_BINARY);
    if (tmpfd < 0)
    {
        perror(tmpname);
        return;
    }

    /* make sure the file hasn't been modified more recently */
    mtime = stbuf.st_mtime;
    fstat(tmpfd, &stbuf);
    if (stbuf.st_mtime < mtime)
    {
        printf("\"%s\" has been modified more recently than its recoverable version\n", filename);
        puts("Do you still want to recover it?\n");
        puts("\ty - Yes, discard the current version and recover it.\n");
        puts("\tn - No, discard the recoverable version and keep the current version\n");
        puts("\tq - Quit without doing anything for this file.\n");
        puts("Enter y, n, or q --> ");
        fflush(stdout);
        for (;;)
        {
            switch (getchar())
            {
              case 'y':
              case 'Y':
                goto BreakBreak;

              case 'n':
              case 'N':
                close(tmpfd);
                unlink(tmpname);
                return;

              case 'q':
              case 'Q':
                close(tmpfd);
                return;
            }
        }
BreakBreak:;
    }

    /* make sure this tmp file is intact */
    if (read(tmpfd, &hdr, (unsigned)BLKSIZE) != BLKSIZE)
    {
        fprintf(stderr, "%s: bad header in tmp file\n", filename);
        close(tmpfd);
        unlink(tmpname);
        return;
    }
    for (i = j = 1; i < MAXBLKS && hdr.n[i]; i++)
    {
        if (hdr.n[i] > j)
        {
            j = hdr.n[i];
        }
    }
    lseek(tmpfd, (long)j * (long)BLKSIZE, 0);
    if (read(tmpfd, &text, (unsigned)BLKSIZE) != BLKSIZE)
    {
        fprintf(stderr, "%s: bad data block in tmp file\n", filename);
        close(tmpfd);
        unlink(tmpname);
        return;
    }

    /* open the normal text file for writing */
    fp = fopen(filename, "w");
    if (!fp)
    {
        perror(filename);
        close(tmpfd);
        return;
    }

    /* copy the text */
    copytext(tmpfd, fp);

    /* cleanup */
    close(tmpfd);
    fclose(fp);
    unlink(tmpname);
}


/* This function moves text from the tmp file to the normal file */
copytext(tmpfd, fp)
    int    tmpfd;    /* fd of the tmp file */
    FILE    *fp;    /* the stream to write it to */
{
    int    i;

    /* write the data blocks to the normal text file */
    for (i = 1; i < MAXBLKS && hdr.n[i]; i++)
    {
        lseek(tmpfd, (long)hdr.n[i] * (long)BLKSIZE, 0);
        read(tmpfd, &text, (unsigned)BLKSIZE);
        fputs(text.c, fp);
    }
}

#if MSDOS || TOS
#define        WILDCARD_NO_MAIN
#include    "wildcard.c"
#endif