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Annotation of coherent/b/kernel/coh.386/fifo.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * File:       fifo.c
        !             3:  *
        !             4:  * Purpose:    allow kernel to fetch data from real-mode bootstrap data area
        !             5:  *
        !             6:  * $Log:       fifo.c,v $
        !             7:  * Revision 1.3  93/04/14  10:06:27  root
        !             8:  * r75
        !             9:  * 
        !            10:  * Revision 1.2  92/01/06  11:59:11  hal
        !            11:  * Compile with cc.mwc.
        !            12:  * 
        !            13:  */
        !            14: 
        !            15: /*
        !            16:  * Includes.
        !            17:  */
        !            18: #define KERNEL
        !            19: #include <sys/typed.h>
        !            20: 
        !            21: /*
        !            22:  * Definitions.
        !            23:  *     Constants.
        !            24:  *     Macros with argument lists.
        !            25:  *     Typedefs.
        !            26:  *     Enums.
        !            27:  */
        !            28: 
        !            29: typedef unsigned char uchar;
        !            30: typedef unsigned int  uint;
        !            31: typedef unsigned long ulong;
        !            32: 
        !            33: /*
        !            34:  * Functions.
        !            35:  *     Import Functions.
        !            36:  *     Export Functions.
        !            37:  *     Local Functions.
        !            38:  */
        !            39: FIFO * fifo_open();
        !            40: int fifo_close();
        !            41: typed_space * fifo_read();
        !            42: 
        !            43: /*
        !            44:  * Global Data.
        !            45:  *     Import Variables.
        !            46:  *     Export Variables.
        !            47:  *     Local Variables.
        !            48:  *
        !            49:  * Arguments are passed into the kernel through boot_gift.
        !            50:  * If you start getting "Not enough room for all arguments." messages
        !            51:  * at boot time, just increase the BG_LEN  to whatever you need.
        !            52:  * This structure is EXACTLY BG_LEN bytes long.
        !            53:  */
        !            54: TYPED_SPACE(boot_gift, BG_LEN, T_FIFO_SIC);
        !            55: 
        !            56: /*
        !            57:  * fifo_open()
        !            58:  *
        !            59:  * Open a typed space as a fifo.
        !            60:  *
        !            61:  * Takes a typed_space that is already allocated, and a mode.    The type of
        !            62:  * the typed space must be a FIFO.  Only T_FIFO_SIC has been implemented
        !            63:  * (static, in-core fifo).
        !            64:  *
        !            65:  * The mode indicates whether to open for reading or writing.
        !            66:  *  mode == 0 means read only.
        !            67:  *  mode == 1 means write only.
        !            68:  *  Other values are illegal.
        !            69:  *
        !            70:  * Returns a pointer to an initialized FIFO structure.  FIFO structures are
        !            71:  * allocated from a pre-allocated array.  Returns F_NULL if it can't open
        !            72:  * the fifo.
        !            73:  */
        !            74: FIFO *
        !            75: fifo_open(fifo_space, mode)
        !            76: typed_space *fifo_space;
        !            77: int mode;
        !            78: {
        !            79:        /* ff_table is a table of FIFO structures which can be allocated on
        !            80:         * demand.  It is functionally similiar to the file descriptor table
        !            81:         * in the kernel.
        !            82:         */
        !            83:        static FIFO ff_table[NFIFOS];
        !            84:        static int inited = 0;  /* Has ff_table been initialized?  */
        !            85: 
        !            86:        int i;          /* A handy counter.  */
        !            87:        FIFO *the_fifo; /* The fifo we are going to allocate.  */
        !            88: 
        !            89:        /* Initialize ff_table the first time we get called.  */
        !            90:        if (!inited) {
        !            91:                for (i = 0; i < NFIFOS; ++i) {
        !            92:                        ff_table[i].f_space = F_NULL;
        !            93:                        ff_table[i].f_flags = 0;
        !            94:                }
        !            95:                inited = 1;
        !            96:        }
        !            97: 
        !            98:        /* Check the type of the space we were passed.  */
        !            99:        switch (fifo_space->ts_type) {
        !           100:        case T_FIFO:    /* Overly general type, assuming SIC.  */
        !           101:                fifo_space->ts_type = T_FIFO_SIC;
        !           102:                break;
        !           103:        case T_FIFO_SIC:        /* Static In-core Fifo.  */
        !           104:                break;
        !           105:        case T_FIFO_DIC:        /* Dynamic In-core Fifo (can grow).  */
        !           106:                return(F_NULL); /* Unimplemented.  */
        !           107:        case T_FIFO_SP: /* Static Permanent Fifo (fixed size file). */
        !           108:                return(F_NULL); /* Unimplemented.  */
        !           109:        case T_FIFO_DP: /* Dynamic Permanent Fifo (ordinary file).  */
        !           110:                return(F_NULL); /* Unimplemented.  */
        !           111:        default:
        !           112:                return(F_NULL); /* Illegal type encountered.  */
        !           113:        }
        !           114: 
        !           115:        /* ASSERTION: fifo_space is a valid and implemented FIFO.  */
        !           116: 
        !           117:        /* Find the first free FIFO structure.  */
        !           118: 
        !           119:        /* This should be re-implemented using a malloc-based scheme.
        !           120:         * At the moment, the tertiary boot libraries do not include a
        !           121:         * malloc.
        !           122:         */
        !           123:        for (i = 0; (i < NFIFOS) && (0 != ff_table[i].f_flags); ++i) {
        !           124:                /* Do nothing else.  */
        !           125:        }
        !           126: 
        !           127:        if (NFIFOS == i) {
        !           128:                return(F_NULL); /* No more free fifo structs.  */
        !           129:        }
        !           130: 
        !           131:        the_fifo = &(ff_table[i]);
        !           132: 
        !           133:        /* ASSERTION: the_fifo points at a FIFO we can take.  */
        !           134: 
        !           135:        /* Initialize the FIFO struct.  */
        !           136:        the_fifo->f_space = fifo_space;
        !           137:        the_fifo->f_offset = fifo_space->ts_data;
        !           138: 
        !           139:        /* Initilize the flags.  */
        !           140:        switch(mode) {
        !           141:        case 0: /* read */
        !           142:                the_fifo->f_flags |= F_READ;
        !           143:                break;
        !           144:        case 1: /* write */
        !           145:                the_fifo->f_flags |= F_WRITE;
        !           146:                break;
        !           147:        default:
        !           148:                return(F_NULL); /* Illegal mode flag.  */
        !           149:        }
        !           150:                
        !           151:        return(the_fifo);
        !           152: } /* fifo_open() */
        !           153: 
        !           154: /*
        !           155:  * fifo_close()
        !           156:  *
        !           157:  * Finish with using a typed space as a fifo.
        !           158:  * Free up FIFO structure associated with a typed space.
        !           159:  * Returns 0 if ffp was not open, 1 otherwise.
        !           160:  */
        !           161: int
        !           162: fifo_close(ffp)
        !           163: FIFO *ffp;
        !           164: {
        !           165:        if (0 == ffp->f_flags) {
        !           166:                return(0);      /* This ffp is not open.  */
        !           167:        }
        !           168:        ffp->f_space = F_NULL;
        !           169:        ffp->f_offset = 0;
        !           170:        ffp->f_flags = 0;
        !           171: 
        !           172:        return(1);
        !           173: } /* fifo_close() */
        !           174: 
        !           175: /*
        !           176:  * fifo_read()
        !           177:  *
        !           178:  * Read a typed space from a fifo.
        !           179:  * Return a pointer to the next typed space in the fifo ffp.  Returns
        !           180:  * NULL on end of fifo.
        !           181:  *
        !           182:  * This read assumes that ffp->f_space has type T_FIFO_SIC.
        !           183:  */
        !           184: typed_space *
        !           185: fifo_read(ffp)
        !           186: register FIFO *ffp;
        !           187: {
        !           188:        typed_space *retval;
        !           189: 
        !           190:        /* Read MUST be set.  */
        !           191:        if (F_READ != F_READ & ffp->f_flags ) {
        !           192: printf(" fifo_read: READ not set ");
        !           193:                return 0;  /* This ffp is not open for reading.  */
        !           194:        }
        !           195: 
        !           196:        /* From here to the end of fifo_read is really fifo_read_sic().  */
        !           197: 
        !           198: 
        !           199:        /* Space of size 0 marks EOFIFO.  */
        !           200:        if ((long)0 == ffp->f_offset->ts_size) {
        !           201: printf(" fifo_read: space of size 0 ");
        !           202:                retval = 0;
        !           203:        } else {
        !           204:                /* Return the next space.  */
        !           205:                retval = ffp->f_offset;
        !           206:                /* Advance to the next space.  */
        !           207:                (char *) ffp->f_offset += ffp->f_offset->ts_size;
        !           208:        }
        !           209: 
        !           210:        return retval;
        !           211: } /* fifo_read() */
        !           212: 
        !           213: #ifdef TEST
        !           214: #include <stdio.h>
        !           215: 
        !           216: /* This is the typed space we will use for our FIFO operations.  */
        !           217: TYPED_SPACE(global_space, 128, T_FIFO_SIC);    /* Static In-Core Fifo.  */
        !           218: 
        !           219: void
        !           220: main()
        !           221: {
        !           222:        FIFO *ffp;              /* Fifo pointer for a handle.  */
        !           223:        char line[1024];        /* Place to put input lines.  */
        !           224:        long size;              /* Length for line.  (Sizes are all long.)  */
        !           225:        int i;
        !           226: 
        !           227:        typed_space *local_space;
        !           228: 
        !           229:        /* Open the fifo for writing.  */
        !           230:        if (F_NULL == (ffp = fifo_open(&global_space, 1))) {
        !           231:                fprintf(stderr, "Can't open global_space for writing.\n");
        !           232:                exit(1);
        !           233:        }
        !           234: 
        !           235:        do {
        !           236:                printf("Feed me: ");
        !           237:                gets(line);
        !           238:                size = (long) (strlen(line) + 1);
        !           239:        } while (fifo_write_untyped(ffp, line, size, T_STR_STR));
        !           240: 
        !           241:        if (0 == fifo_close(ffp)) {
        !           242:                fprintf(stderr, "Failed to close global_space.\n");
        !           243:                exit(1);
        !           244:        }
        !           245: 
        !           246:        printf("OK, global_space is now full.\n");
        !           247:        /* ASSERTION: We've filled global_space with strings.  */
        !           248: 
        !           249:        /* Open the fifo for reading.  */
        !           250:        if (F_NULL == (ffp = fifo_open(&global_space, 0))) {
        !           251:                fprintf(stderr, "Can't open global_space for reading.\n");
        !           252:                exit(1);
        !           253:        }
        !           254: 
        !           255:        /* Dump the contents of this FIFO.  */
        !           256:        for (i = 1; (local_space = fifo_read(ffp)); ++i) {
        !           257:                printf("%d: size: %ld: type: 0x%x\n", i,
        !           258:                        local_space->ts_size,
        !           259:                        local_space->ts_type);
        !           260: 
        !           261:                /* Assume everything is a NUL terminated string.  */
        !           262:                printf("datum: %s\n\n", local_space->ts_data);
        !           263:                printf("Hit <RETURN>");
        !           264:                gets(line);
        !           265:        }
        !           266: 
        !           267: 
        !           268:        /* Rewind the file, and dump it out again.  */
        !           269:        printf("Rewinding.\n");
        !           270:        if (0 == fifo_rewind(ffp)) {
        !           271:                fprintf("Can't rewind global_space.\n");
        !           272:                exit(1);
        !           273:        }
        !           274: 
        !           275:        for (i = 1; (local_space = fifo_read(ffp)); ++i) {
        !           276:                printf("%d: size: %ld: type: 0x%x\n", i,
        !           277:                        local_space->ts_size,
        !           278:                        local_space->ts_type);
        !           279: 
        !           280:                /* Assume everything is a NUL terminated string.  */
        !           281:                printf("datum: %s\n\n", local_space->ts_data);
        !           282:        }
        !           283: 
        !           284:        if (0 == fifo_close(ffp)) {
        !           285:                fprintf(stderr, "Failed to close global_space.\n");
        !           286:                exit(1);
        !           287:        }
        !           288: 
        !           289:        exit(0);
        !           290: } /* main() */
        !           291: 
        !           292: #endif /* TEST */

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