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

1.1     ! root        1: /* $Header: /y/coh.386/RCS/fd.c,v 1.5 93/04/14 10:06:26 root Exp $ */
        !             2: /* (lgl-
        !             3:  *     The information contained herein is a trade secret of Mark Williams
        !             4:  *     Company, and  is confidential information.  It is provided  under a
        !             5:  *     license agreement,  and may be  copied or disclosed  only under the
        !             6:  *     terms of  that agreement.  Any  reproduction or disclosure  of this
        !             7:  *     material without the express written authorization of Mark Williams
        !             8:  *     Company or persuant to the license agreement is unlawful.
        !             9:  *
        !            10:  *     COHERENT Version 2.3.37
        !            11:  *     Copyright (c) 1982, 1983, 1984.
        !            12:  *     An unpublished work by Mark Williams Company, Chicago.
        !            13:  *     All rights reserved.
        !            14:  -lgl) */
        !            15: /*
        !            16:  * Coherent.
        !            17:  * File descriptor routines.
        !            18:  *
        !            19:  * $Log:       fd.c,v $
        !            20:  * Revision 1.5  93/04/14  10:06:26  root
        !            21:  * r75
        !            22:  * 
        !            23:  * Revision 1.3  92/06/10  12:52:39  hal
        !            24:  * First record locking changes.
        !            25:  * 
        !            26:  * Revision 1.2  92/01/06  11:59:07  hal
        !            27:  * Compile with cc.mwc.
        !            28:  * 
        !            29:  * Revision 1.1        88/03/24  16:13:43      src
        !            30:  * Initial revision
        !            31:  * 
        !            32:  */
        !            33: #include <sys/coherent.h>
        !            34: #include <errno.h>
        !            35: #include <fcntl.h>
        !            36: #include <sys/fd.h>
        !            37: #include <sys/inode.h>
        !            38: 
        !            39: /*
        !            40:  * Given a file number, return the file descriptor.
        !            41:  */
        !            42: FD *
        !            43: fdget(fd)
        !            44: register unsigned fd;
        !            45: {
        !            46:        register FD *fdp;
        !            47: 
        !            48:        if (fd>=NOFILE || (fdp=u.u_filep[fd])==NULL) {
        !            49:                u.u_error = EBADF;
        !            50:                return (NULL);
        !            51:        }
        !            52:        return (fdp);
        !            53: }
        !            54: 
        !            55: /*
        !            56:  * NIGEL: To help fix some stupid bugs with uopen (), I have split the
        !            57:  * fdopen () routine into three parts; one for resource allocation, one for
        !            58:  * setting the inode member and opening the inode, and one for finishing up
        !            59:  * an open.
        !            60:  */
        !            61: 
        !            62: /*
        !            63:  * This function finds a free slot in the process file descriptor table and
        !            64:  * fills it in with a partially initialised entry.
        !            65:  *
        !            66:  * This function returns a file descriptor number on success, -1 on failure.
        !            67:  */
        !            68: 
        !            69: int fdalloc ()
        !            70: {
        !            71:        int             i;
        !            72: 
        !            73:        for (i = 0 ; i < sizeof (u.u_filep) / sizeof (* u.u_filep) ; i ++) {
        !            74:                if (u.u_filep [i] == NULL) {
        !            75:                        FD    * filep;
        !            76: 
        !            77:                        if ((filep = u.u_filep [i] = kalloc (sizeof (FD)))
        !            78:                                        == NULL) {
        !            79:                                /*
        !            80:                                 * Insufficient resources!
        !            81:                                 */
        !            82: 
        !            83:                                u.u_error = EAGAIN;
        !            84:                                return -1;
        !            85:                        }
        !            86: 
        !            87:                        filep->f_flag = 0;
        !            88:                        filep->f_flag2 = 0;
        !            89:                        filep->f_refc = 0;
        !            90:                        filep->f_seek = 0;
        !            91:                        filep->f_ip = NULL;
        !            92: 
        !            93:                        return i;
        !            94:                }
        !            95:        }
        !            96: 
        !            97:        u.u_error = EMFILE;
        !            98:        return -1;
        !            99: }
        !           100: 
        !           101: /*
        !           102:  * This function performs the second half of the file open process by filling
        !           103:  * in the inode member of the file table entry and requesting that the inode be
        !           104:  * opened.
        !           105:  *
        !           106:  * This function returns -1 on error, 0 on success.
        !           107:  */
        !           108: 
        !           109: int fdinit (fd, ip, mode)
        !           110: int            fd;
        !           111: INODE        * ip;
        !           112: int            mode;
        !           113: {
        !           114:        FD            * filep;
        !           115: 
        !           116:        if ((filep = fdget (fd)) == NULL)
        !           117:                return -1;
        !           118: 
        !           119:        iopen (ip, mode);
        !           120: 
        !           121:        if (u.u_error != 0)
        !           122:                return -1;
        !           123: 
        !           124:        filep->f_ip = ip;
        !           125:        filep->f_flag = mode;
        !           126:        filep->f_refc = 1;
        !           127: 
        !           128:        return 0;
        !           129: }
        !           130: 
        !           131: 
        !           132: /*
        !           133:  * This function finalises an open; normally this does nothing, but if there
        !           134:  * has been an error, this code will take care of deallocating the entry.
        !           135:  *
        !           136:  * This function returns the file descriptor number on success, or -1 on error.
        !           137:  */
        !           138: 
        !           139: int fdfinish (fd)
        !           140: int            fd;
        !           141: {
        !           142:        FD            * filep;
        !           143: 
        !           144:        if ((filep = fdget (fd)) == NULL)
        !           145:                return -1;
        !           146: 
        !           147:        if (filep->f_refc == 0) {
        !           148:                /*
        !           149:                 * The open never really succeeded, release resources.
        !           150:                 */
        !           151: 
        !           152:                kfree (filep);
        !           153:                u.u_filep [fd] = NULL;
        !           154:                fd = -1;
        !           155:        }
        !           156: 
        !           157:        return fd;
        !           158: }
        !           159: 
        !           160: 
        !           161: /*
        !           162:  * Given an inode, and a mode containing permission flags, open the
        !           163:  * inode with the appropriate permissions and return a file descriptor
        !           164:  * containing it.
        !           165:  */
        !           166: fdopen(ip, mode)
        !           167: register INODE *ip;
        !           168: {
        !           169:        int             fd;
        !           170: 
        !           171:        if ((fd = fdalloc ()) >= 0) {
        !           172:                fdinit (fd, ip, mode);
        !           173:                fd = fdfinish (fd);
        !           174:        }
        !           175: 
        !           176:        return fd;
        !           177: }
        !           178: 
        !           179: 
        !           180: /*
        !           181:  * Close the given file number.
        !           182:  */
        !           183: fdclose(fd)
        !           184: register unsigned fd;
        !           185: {
        !           186:        register FD *fdp;
        !           187:        static  FLOCK   flock = { F_UNLCK, 0, 0, 0 };
        !           188: 
        !           189:        if (fd>=NOFILE || (fdp=u.u_filep[fd])==NULL) {
        !           190:                u.u_error = EBADF;
        !           191:                return;
        !           192:        }
        !           193:        if (fdp->f_ip->i_rl != NULL)
        !           194:                rlock(fdp, F_SETLK, &flock);    /* delete all record locks */
        !           195:        u.u_filep[fd] = NULL;
        !           196:        if (fdp->f_refc == 0)
        !           197:                panic("fdclose()");
        !           198:        if (--fdp->f_refc == 0) {
        !           199:                iclose(fdp->f_ip, fdp->f_flag);
        !           200:                kfree(fdp);
        !           201:        }
        !           202: }
        !           203: 
        !           204: /*
        !           205:  * Assuming we have made a copy of the user area, increment the reference
        !           206:  * of all open files.  (used in fork).
        !           207:  */
        !           208: fdadupl()
        !           209: {
        !           210:        register FD **fdpp;
        !           211:        register FD *fdp;
        !           212: 
        !           213:        for (fdpp=u.u_filep; fdpp<&u.u_filep[NOFILE]; fdpp++) {
        !           214:                if ((fdp=*fdpp) == NULL)
        !           215:                        continue;
        !           216:                fdp->f_refc++;
        !           217:        }
        !           218: }
        !           219: 
        !           220: /*
        !           221:  * Close all open files in the current process.
        !           222:  */
        !           223: fdaclose()
        !           224: {
        !           225:        register int fd;
        !           226: 
        !           227:        for (fd=0; fd<NOFILE; fd++) {
        !           228:                if (u.u_filep[fd] == NULL)
        !           229:                        continue;
        !           230:                fdclose(fd);
        !           231:        }
        !           232: }

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