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Annotation of coherent/g/usr/lib/misc/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 1.2  92/07/15  08:46:24  bin
        !             8:  * *** empty log message ***
        !             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: 
        !            19: #define __KERNEL__ 1
        !            20: #include <kernel/typed.h>
        !            21: 
        !            22: #ifndef T_NULL
        !            23: #define T_NULL ((char *)0)
        !            24: #endif
        !            25: 
        !            26: /*
        !            27:  * Definitions.
        !            28:  *     Constants.
        !            29:  *     Macros with argument lists.
        !            30:  *     Typedefs.
        !            31:  *     Enums.
        !            32:  */
        !            33: 
        !            34: typedef unsigned char uchar;
        !            35: typedef unsigned int  uint;
        !            36: typedef unsigned long ulong;
        !            37: 
        !            38: /*
        !            39:  * Functions.
        !            40:  *     Import Functions.
        !            41:  *     Export Functions.
        !            42:  *     Local Functions.
        !            43:  */
        !            44: FIFO * fifo_open();
        !            45: int fifo_close();
        !            46: typed_space * fifo_read();
        !            47: 
        !            48: /*
        !            49:  * Global Data.
        !            50:  *     Import Variables.
        !            51:  *     Export Variables.
        !            52:  *     Local Variables.
        !            53:  *
        !            54:  * Arguments are passed into the kernel through boot_gift.
        !            55:  * If you start getting "Not enough room for all arguments." messages
        !            56:  * at boot time, just increase the BG_LEN  to whatever you need.
        !            57:  * This structure is EXACTLY BG_LEN bytes long.
        !            58:  */
        !            59: TYPED_SPACE(boot_gift, BG_LEN, T_FIFO_SIC);
        !            60: 
        !            61: /*
        !            62:  * fifo_open()
        !            63:  *
        !            64:  * Open a typed space as a fifo.
        !            65:  *
        !            66:  * Takes a typed_space that is already allocated, and a mode.    The type of
        !            67:  * the typed space must be a FIFO.  Only T_FIFO_SIC has been implimented
        !            68:  * (static, in-core fifo).
        !            69:  *
        !            70:  * The mode indicates whether to open for reading or writing.
        !            71:  *  mode == 0 means read only.
        !            72:  *  mode == 1 means write only.
        !            73:  *  Other values are illegal.
        !            74:  *
        !            75:  * Returns a pointer to an initialized FIFO structure.  FIFO structures are
        !            76:  * allocated from a pre-allocated array.  Returns F_NULL if it can't open
        !            77:  * the fifo.
        !            78:  */
        !            79: FIFO *
        !            80: fifo_open(fifo_space, mode)
        !            81:        typed_space *fifo_space;
        !            82:        int mode;
        !            83: {
        !            84:        /* ff_table is a table of FIFO structures which can be allocated on
        !            85:         * demand.  It is functionally similiar to the file descritor table
        !            86:         * in the kernel.
        !            87:         */
        !            88:        static FIFO ff_table[NFIFOS];
        !            89:        static int inited = (1==2);     /* Has ff_table been initialized?  */
        !            90: 
        !            91:        int i;          /* A handy counter.  */
        !            92:        FIFO *the_fifo; /* The fifo we are going to allocate.  */
        !            93: 
        !            94:        /* Initilize ff_table the first time we get called.  */
        !            95:        if (!inited) {
        !            96:                for (i = 0; i < NFIFOS; ++i) {
        !            97:                        ff_table[i].f_space = F_NULL;
        !            98:                        ff_table[i].f_flags = 0;
        !            99:                }
        !           100:                inited = 1;
        !           101:        }
        !           102: 
        !           103:        /* Check the type of the space we were passed.  */
        !           104:        switch (fifo_space->ts_type) {
        !           105:        case T_FIFO:    /* Overly general type, assuming SIC.  */
        !           106:                fifo_space->ts_type = T_FIFO_SIC;
        !           107:                break;
        !           108:        case T_FIFO_SIC:        /* Static In-core Fifo.  */
        !           109:                break;
        !           110:        case T_FIFO_DIC:        /* Dynamic In-core Fifo (can grow).  */
        !           111:                return(F_NULL); /* Unimplimented.  */
        !           112:        case T_FIFO_SP: /* Static Permanent Fifo (fixed size file). */
        !           113:                return(F_NULL); /* Unimplimented.  */
        !           114:        case T_FIFO_DP: /* Dynamic Permanent Fifo (ordinary file).  */
        !           115:                return(F_NULL); /* Unimplimented.  */
        !           116:        default:
        !           117:                return(F_NULL); /* Illegal type encountered.  */
        !           118:        }
        !           119: 
        !           120:        /* ASSERTION: fifo_space is a valid and implimented FIFO.  */
        !           121: 
        !           122:        /* Find the first free FIFO structure.  */
        !           123: 
        !           124:        /* This should be re-implimented using a malloc-based scheme.
        !           125:         * At the moment, the tertiary boot libraries do not include a
        !           126:         * malloc.
        !           127:         */
        !           128:        for (i = 0; (i < NFIFOS) && (0 != ff_table[i].f_flags); ++i) {
        !           129:                /* Do nothing else.  */
        !           130:        }
        !           131: 
        !           132:        if (NFIFOS == i) {
        !           133:                return(F_NULL); /* No more free fifo structs.  */
        !           134:        }
        !           135: 
        !           136:        the_fifo = &(ff_table[i]);
        !           137: 
        !           138:        /* ASSERTION: the_fifo points at a FIFO we can take.  */
        !           139: 
        !           140:        /* Initialize the FIFO struct.  */
        !           141:        the_fifo->f_space = fifo_space;
        !           142:        the_fifo->f_offset = fifo_space->ts_data;
        !           143: 
        !           144:        /* Initilize the flags.  */
        !           145:        switch(mode) {
        !           146:        case 0: /* read */
        !           147:                the_fifo->f_flags |= F_READ;
        !           148:                break;
        !           149:        case 1: /* write */
        !           150:                the_fifo->f_flags |= F_WRITE;
        !           151:                break;
        !           152:        default:
        !           153:                return(F_NULL); /* Illegal mode flag.  */
        !           154:        }
        !           155:                
        !           156:        return(the_fifo);
        !           157: } /* fifo_open() */
        !           158: 
        !           159: /*
        !           160:  * fifo_close()
        !           161:  *
        !           162:  * Finish with using a typed space as a fifo.
        !           163:  * Free up FIFO structure associated with a typed space.
        !           164:  * Returns 0 if ffp was not open, 1 otherwise.
        !           165:  */
        !           166: int
        !           167: fifo_close(ffp)
        !           168:        FIFO *ffp;
        !           169: {
        !           170:        if (0 == ffp->f_flags) {
        !           171:                return(0);      /* This ffp is not open.  */
        !           172:        }
        !           173:        ffp->f_space = F_NULL;
        !           174:        ffp->f_offset = T_NULL;
        !           175:        ffp->f_flags = 0;
        !           176: 
        !           177:        return(1);
        !           178: } /* fifo_close() */
        !           179: 
        !           180: /*
        !           181:  * fifo_read()
        !           182:  *
        !           183:  * Read a typed space from a fifo.
        !           184:  * Return a pointer to the next typed space in the fifo ffp.  Returns
        !           185:  * NULL on end of fifo.
        !           186:  *
        !           187:  * This read assumes that ffp->f_space has type T_FIFO_SIC.
        !           188:  */
        !           189: typed_space *
        !           190: fifo_read(ffp)
        !           191:        register FIFO *ffp;
        !           192: {
        !           193:        typed_space *retval;
        !           194: 
        !           195:        /* Read MUST be set.  */
        !           196:        if (F_READ != F_READ & ffp->f_flags ) {
        !           197:                return(T_NULL);  /* This ffp is not open for reading.  */
        !           198:        }
        !           199: 
        !           200:        /* From here to the end of fifo_read is really fifo_read_sic().  */
        !           201: 
        !           202: 
        !           203:        /* Space of size 0 marks EOFIFO.  */
        !           204:        if ((long)0 == ffp->f_offset->ts_size) {
        !           205:                retval = T_NULL;
        !           206:        } else {
        !           207:                /* Return the next space.  */
        !           208:                retval = ffp->f_offset;
        !           209:                /* Advance to the next space.  */
        !           210:                (char *) ffp->f_offset += ffp->f_offset->ts_size;
        !           211:        }
        !           212: 
        !           213:        return(retval);
        !           214: } /* fifo_read() */
        !           215: 
        !           216: #ifdef TEST
        !           217: #include <stdio.h>
        !           218: 
        !           219: /* This is the typed space we will use for our FIFO operations.  */
        !           220: TYPED_SPACE(global_space, 128, T_FIFO_SIC);    /* Static In-Core Fifo.  */
        !           221: 
        !           222: int
        !           223: main()
        !           224: {
        !           225:        FIFO *ffp;              /* Fifo pointer for a handle.  */
        !           226:        char line[1024];        /* Place to put input lines.  */
        !           227:        long size;              /* Length for line.  (Sizes are all long.)  */
        !           228:        int i;
        !           229: 
        !           230:        typed_space *local_space;
        !           231: 
        !           232:        /* Open the fifo for writing.  */
        !           233:        if (F_NULL == (ffp = fifo_open(&global_space, 1))) {
        !           234:                fprintf(stderr, "Can't open global_space for writing.\n");
        !           235:                exit(1);
        !           236:        }
        !           237: 
        !           238:        do {
        !           239:                printf("Feed me: ");
        !           240:                gets(line);
        !           241:                size = (long) (strlen(line) + 1);
        !           242:        } while (T_NULL != fifo_write_untyped(ffp, line, size, T_STR_STR));
        !           243: 
        !           244:        if (0 == fifo_close(ffp)) {
        !           245:                fprintf(stderr, "Failed to close global_space.\n");
        !           246:                exit(1);
        !           247:        }
        !           248: 
        !           249:        printf("OK, global_space is now full.\n");
        !           250:        /* ASSERTION: We've filled global_space with strings.  */
        !           251: 
        !           252:        /* Open the fifo for reading.  */
        !           253:        if (F_NULL == (ffp = fifo_open(&global_space, 0))) {
        !           254:                fprintf(stderr, "Can't open global_space for reading.\n");
        !           255:                exit(1);
        !           256:        }
        !           257: 
        !           258:        /* Dump the contents of this FIFO.  */
        !           259:        for (i = 1; T_NULL != (local_space = fifo_read(ffp)); ++i) {
        !           260:                printf("%d: size: %ld: type: 0x%x\n", i,
        !           261:                        local_space->ts_size,
        !           262:                        local_space->ts_type);
        !           263: 
        !           264:                /* Assume everything is a NUL terminated string.  */
        !           265:                printf("datum: %s\n\n", local_space->ts_data);
        !           266:                printf("Hit <RETURN>");
        !           267:                gets(line);
        !           268:        }
        !           269: 
        !           270: 
        !           271:        /* Rewind the file, and dump it out again.  */
        !           272:        printf("Rewinding.\n");
        !           273:        if (0 == fifo_rewind(ffp)) {
        !           274:                fprintf("Can't rewind global_space.\n");
        !           275:                exit(1);
        !           276:        }
        !           277: 
        !           278:        for (i = 1; T_NULL != (local_space = fifo_read(ffp)); ++i) {
        !           279:                printf("%d: size: %ld: type: 0x%x\n", i,
        !           280:                        local_space->ts_size,
        !           281:                        local_space->ts_type);
        !           282: 
        !           283:                /* Assume everything is a NUL terminated string.  */
        !           284:                printf("datum: %s\n\n", local_space->ts_data);
        !           285:        }
        !           286: 
        !           287:        if (0 == fifo_close(ffp)) {
        !           288:                fprintf(stderr, "Failed to close global_space.\n");
        !           289:                exit(1);
        !           290:        }
        !           291: 
        !           292:        exit(0);
        !           293: } /* main() */
        !           294: 
        !           295: #endif /* TEST */

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