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Annotation of 43BSD/games/adventure/save.c, revision 1.1

1.1     ! root        1: /* save (III)   J. Gillogly
        !             2:  * save user core image for restarting
        !             3:  * usage: save(<command file (argv[0] from main)>,<output file>)
        !             4:  * bugs
        !             5:  *   -  impure code (i.e. changes in instructions) is not handled
        !             6:  *      (but people that do that get what they deserve)
        !             7:  */
        !             8: 
        !             9: static char sccsid[] = "       save.c  4.1     82/05/11        ";
        !            10: 
        !            11: #include <a.out.h>
        !            12: int filesize;                    /* accessible to caller         */
        !            13: 
        !            14: char *sbrk();
        !            15: 
        !            16: save(cmdfile,outfile)                   /* save core image              */
        !            17: char *cmdfile,*outfile;
        !            18: {       register char *c;
        !            19:        register int i,fd;
        !            20:        int fdaout;
        !            21:        struct exec header;
        !            22:        int counter;
        !            23:        char buff[512],pwbuf[120];
        !            24:        fdaout=getcmd(cmdfile);         /* open command wherever it is  */
        !            25:        if (fdaout<0) return(-1);       /* can do nothing without text  */
        !            26:        if ((fd=open(outfile,0))>0)     /* this restriction is so that  */
        !            27:        {       printf("Can't use an existing file\n"); /* we don't try */
        !            28:                close(fd);              /* to write over the commnd file*/
        !            29:                return(-1);
        !            30:        }
        !            31:        if ((fd=creat(outfile,0755))== -1)
        !            32:        {       printf("Cannot create %s\n",outfile);
        !            33:                return(-1);
        !            34:        }
        !            35:        /* can get the text segment from the command that we were
        !            36:         * called with, and change all data from uninitialized to
        !            37:         * initialized.  It will start at the top again, so the user
        !            38:         * is responsible for checking whether it was restarted
        !            39:         * could ignore sbrks and breaks for the first pass
        !            40:         */
        !            41:        read(fdaout,&header,sizeof header);/* get the header       */
        !            42:        header.a_bss = 0;                  /* no data uninitialized        */
        !            43:        header.a_syms = 0;                 /* throw away symbol table      */
        !            44:        switch (header.a_magic)            /* find data segment            */
        !            45:        {   case 0407:                     /* non sharable code            */
        !            46:                c = (char *) header.a_text;/* data starts right after text */
        !            47:                header.a_data=sbrk(0)-c;   /* current size (incl allocs)   */
        !            48:                break;
        !            49:            case 0410:                     /* sharable code                */
        !            50:                c = (char *)
        !            51: #ifdef pdp11
        !            52:                    (header.a_text         /* starts after text            */
        !            53:                    & 0160000)             /* on an 8K boundary            */
        !            54:                    +  020000;             /* i.e. the next one up         */
        !            55: #endif
        !            56: #ifdef vax
        !            57:                    (header.a_text         /* starts after text            */
        !            58:                    & 037777776000)        /* on an 1K boundary            */
        !            59:                    +        02000;        /* i.e. the next one up         */
        !            60: #endif
        !            61: #ifdef z8000
        !            62:                    (header.a_text         /* starts after text            */
        !            63:                    & 0174000)             /* on an 2K boundary            */
        !            64:                    +  004000;             /* i.e. the next one up         */
        !            65: #endif
        !            66:                header.a_data=sbrk(0)-c;   /* current size (incl allocs)   */
        !            67:                break;
        !            68:            case 0411:                     /* sharable with split i/d      */
        !            69:                c = 0;                     /* can't reach text             */
        !            70:                header.a_data=(int)sbrk(0);/* current size (incl allocs)   */
        !            71:                break;
        !            72:            case 0413:
        !            73:                c = (char *) header.a_text;/* starts after text            */
        !            74:                lseek(fdaout, 1024L, 0);   /* skip unused part of 1st block*/
        !            75:        }
        !            76:        if (header.a_data<0)               /* data area very big           */
        !            77:                return(-1);                /* fail for now                 */
        !            78: 
        !            79:        filesize=sizeof header+header.a_text+header.a_data;
        !            80:        write(fd,&header,sizeof header);   /* make the new header          */
        !            81:        if (header.a_magic==0413)
        !            82:                lseek(fd, 1024L, 0);       /* Start on 1K boundary         */
        !            83:        counter=header.a_text;             /* size of text                 */
        !            84:        while (counter>512)                /* copy 512-byte blocks         */
        !            85:        {       read(fdaout,buff,512);     /* as long as possible          */
        !            86:                write(fd,buff,512);
        !            87:                counter -= 512;
        !            88:        }
        !            89:        read(fdaout,buff,counter);         /* then pick up the rest        */
        !            90:        write(fd,buff,counter);
        !            91:        write(fd,c,header.a_data);         /* write all data in 1 glob     */
        !            92:        close(fd);
        !            93: }
        !            94: 
        !            95: #define        NULL    0
        !            96: 
        !            97: char   *execat(), *getenv();
        !            98: 
        !            99: getcmd(command)         /* get command name (wherever it is) like shell */
        !           100: char *command;
        !           101: {
        !           102:        char *pathstr;
        !           103:        register char *cp;
        !           104:        char fname[128];
        !           105:        int fd;
        !           106: 
        !           107:        if ((pathstr = getenv("PATH")) == NULL)
        !           108:                pathstr = ":/bin:/usr/bin";
        !           109:        cp = index(command, '/')? "": pathstr;
        !           110: 
        !           111:        do {
        !           112:                cp = execat(cp, command, fname);
        !           113:                if ((fd=open(fname,0))>0)
        !           114:                        return(fd);
        !           115:        } while (cp);
        !           116: 
        !           117:        printf("Couldn't open %s\n",command);
        !           118:        return(-1);
        !           119: }
        !           120: 
        !           121: static char *
        !           122: execat(s1, s2, si)
        !           123: register char *s1, *s2;
        !           124: char *si;
        !           125: {
        !           126:        register char *s;
        !           127: 
        !           128:        s = si;
        !           129:        while (*s1 && *s1 != ':' && *s1 != '-')
        !           130:                *s++ = *s1++;
        !           131:        if (si != s)
        !           132:                *s++ = '/';
        !           133:        while (*s2)
        !           134:                *s++ = *s2++;
        !           135:        *s = '\0';
        !           136:        return(*s1? ++s1: 0);
        !           137: }

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