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Annotation of coherent/d/PS2_KERNEL/io.286/shm.c, revision 1.1

1.1     ! root        1: /* $Header: /kernel/kersrc/io.286/shm.c,v 1.1 92/07/17 15:24:46 bin Exp Locker: bin $
        !             2:  *
        !             3:  *     The  information  contained herein  is a trade secret  of INETCO
        !             4:  *     Systems, and is confidential information.   It is provided under
        !             5:  *     a license agreement,  and may be copied or disclosed  only under
        !             6:  *     the terms of that agreement.   Any reproduction or disclosure of
        !             7:  *     this  material  without  the express  written  authorization  of
        !             8:  *     INETCO Systems or persuant to the license agreement is unlawful.
        !             9:  *
        !            10:  *     Copyright (c) 1985, 1984
        !            11:  *     An unpublished work by INETCO Systems, Ltd.
        !            12:  *     All rights reserved.
        !            13:  */
        !            14: 
        !            15: /*
        !            16:  * System V Compatible Shared Memory Device Driver
        !            17:  *
        !            18:  *     This device driver provides System V compatible shared memory operations.
        !            19:  *     Operations are performed through the shared memory device (/dev/shm).
        !            20:  *     and are implemented as ioctl calls from shmctl, shmget, shmat, shmdt
        !            21:  *     utilities.
        !            22:  *
        !            23:  *                     Author: Allan Cornish, INETCO Systems Ltd., Sep 1984
        !            24:  *
        !            25:  * $Log:       shm.c,v $
        !            26:  * Revision 1.1  92/07/17  15:24:46  bin
        !            27:  * Initial revision
        !            28:  * 
        !            29:  * Revision 2.1        88/09/03  13:12:17      src
        !            30:  * *** empty log message ***
        !            31:  * 
        !            32:  * Revision 1.1        88/03/24  17:06:32      src
        !            33:  * Initial revision
        !            34:  * 
        !            35:  * 85/10/16    Allan Cornish
        !            36:  * Driver split into shmcon.c, shm.c [driver implementation, System V shm].
        !            37:  *
        !            38:  * 85/07/22    Allan Cornish
        !            39:  * Shmget, shmctl now return immediately if u.u_error is set.
        !            40:  *
        !            41:  * 85/07/19    Allan Cornish
        !            42:  * Separation of io_seek into shmid and off improved through type casting.
        !            43:  * Errno set to EFAULT if fucopy() or ufcopy() report no bytes transferred.
        !            44:  * This would occur if an user address fault occurred.
        !            45:  *
        !            46:  * 85/07/03    Allan Cornish
        !            47:  * Replaced use of EDOM with EIDRM.
        !            48:  * Replaced shmaccess() by calls to ipcaccess(), increasing shared ipc code.
        !            49:  * Eliminated shmlock() and shmunlock(), as shared memory use is synchronous.
        !            50:  */
        !            51: 
        !            52: #include <coherent.h>
        !            53: #include <sched.h>
        !            54: #include <types.h>
        !            55: #include <errno.h>
        !            56: #include <stat.h>
        !            57: #include <con.h>
        !            58: #include <seg.h>
        !            59: #include <shm.h>
        !            60: 
        !            61: #ifndef        EIDRM
        !            62: #define        EIDRM   EDOM
        !            63: #endif
        !            64: 
        !            65: 
        !            66: extern unsigned NSHMID;
        !            67: extern struct shmid_ds *shmids;
        !            68: extern struct seg **shmsegs;
        !            69: 
        !            70: /*
        !            71:  * Shmctl - Shared Memory Control Operations.
        !            72:  */
        !            73: 
        !            74: ushmctl( shmid, cmd, buf )
        !            75: 
        !            76: unsigned shmid;
        !            77: int cmd;
        !            78: struct shmid_ds *buf;
        !            79: 
        !            80: {
        !            81:        register struct shmid_ds *idp;
        !            82:        int ret = 0;
        !            83: 
        !            84:        if ( u.u_error )
        !            85:                return -1;
        !            86: 
        !            87:        if ( shmid >= NSHMID ) {
        !            88:                u.u_error = EINVAL;
        !            89:                return -1;
        !            90:        }
        !            91: 
        !            92:        idp = &shmids[shmid];
        !            93: 
        !            94:        if ( (idp->shm_perm.mode & IPC_ALLOC) == 0 ) {
        !            95:                u.u_error = EINVAL;
        !            96:                return -1;
        !            97:        }
        !            98: 
        !            99:        switch ( cmd ) {
        !           100: 
        !           101:        case IPC_STAT:
        !           102:                if ( ( ipcaccess( &idp->shm_perm ) & SHM_R ) == 0 ) {
        !           103:                        u.u_error = EACCES;
        !           104:                        return -1;
        !           105:                }
        !           106:                kucopy( idp, buf, sizeof(struct shmid_ds) );
        !           107:                ret = 0;
        !           108:                break;
        !           109: 
        !           110:        case IPC_SET:
        !           111:                if ( (u.u_uid != 0) && (u.u_uid != idp->shm_perm.uid) ) {
        !           112:                        u.u_error = EPERM;
        !           113:                        ret = -1;
        !           114:                        break;
        !           115:                }
        !           116:                idp->shm_perm.uid   = getuwd( &(buf->shm_perm.uid ) );
        !           117:                idp->shm_perm.gid   = getuwd( &(buf->shm_perm.gid ) );
        !           118:                idp->shm_perm.mode &= ~0777;
        !           119:                idp->shm_perm.mode |= getuwd(&(buf->shm_perm.mode)) & 0777;
        !           120:                ret = 0;
        !           121:                break;
        !           122: 
        !           123:        case IPC_RMID:
        !           124:                if ( (u.u_uid != 0) && (u.u_uid != idp->shm_perm.uid) ) {
        !           125:                        u.u_error = EPERM;
        !           126:                        ret = -1;
        !           127:                        break;
        !           128:                }
        !           129:                idp->shm_perm.seq++;
        !           130:                sfree(shmsegs[shmid]);
        !           131:                idp->shm_perm.mode = 0;
        !           132:                ret = 0;
        !           133:                break;
        !           134: 
        !           135:        default:
        !           136:                u.u_error = EINVAL;
        !           137:                ret = -1;
        !           138:        }
        !           139: 
        !           140:        return ret;
        !           141: }
        !           142: 
        !           143: /*
        !           144:  * Shmget - Get Shared Memory Segment
        !           145:  */
        !           146: 
        !           147: ushmget( skey, size, shmflg )
        !           148: 
        !           149: key_t skey;
        !           150: unsigned size;
        !           151: int shmflg;
        !           152: 
        !           153: {
        !           154:        register struct shmid_ds *idp;
        !           155:        struct shmid_ds *freeidp = 0;
        !           156: 
        !           157:        if ( u.u_error )
        !           158:                return -1;
        !           159: 
        !           160:        for ( idp = &shmids[NSHMID]; --idp >= shmids; ) {
        !           161: 
        !           162:                if ( (idp->shm_perm.mode & IPC_ALLOC) == 0 ) {
        !           163: 
        !           164:                        if ((freeidp == 0) ||
        !           165:                            (freeidp->shm_ctime > idp->shm_ctime))
        !           166:                                freeidp = idp;
        !           167:                        continue;
        !           168:                }
        !           169: 
        !           170: #ifdef IPC_PRIVATE
        !           171:                if (skey == IPC_PRIVATE)
        !           172:                        continue;
        !           173: #endif
        !           174: 
        !           175:                if (skey == idp->shm_perm.key) {                /* found! */
        !           176: 
        !           177:                        if ( (shmflg & IPC_CREAT) && (shmflg & IPC_EXCL) ) {
        !           178: 
        !           179:                                u.u_error = EEXIST;
        !           180:                                return -1;
        !           181:                        }
        !           182: 
        !           183:                        if ((idp->shm_perm.mode & shmflg) != (shmflg&0777)) {
        !           184: 
        !           185:                                u.u_error = EACCES;
        !           186:                                return -1;
        !           187:                        }
        !           188: 
        !           189:                        if ( idp->shm_segsz < size ) {
        !           190: 
        !           191:                                u.u_error = EINVAL;
        !           192:                                return -1;
        !           193:                        }
        !           194: 
        !           195:                        return idp - shmids;
        !           196:                }
        !           197:        }
        !           198: 
        !           199:        if ( !(shmflg & IPC_CREAT) ) {
        !           200:                u.u_error = ENOENT;
        !           201:                return -1;
        !           202:        }
        !           203: 
        !           204:        if ( freeidp == 0 ) {
        !           205:                u.u_error = ENOSPC;
        !           206:                return -1;
        !           207:        }
        !           208: 
        !           209:        idp = freeidp;
        !           210: 
        !           211:        if ((shmsegs[idp - shmids] = salloc((size_t) size, SFNSWP)) == NULL){
        !           212:                u.u_error = ENOSPC;
        !           213:                return -1;
        !           214:        }
        !           215: 
        !           216:        idp->shm_segsz = size;
        !           217:        idp->shm_atime = 0;
        !           218:        idp->shm_dtime = 0;
        !           219:        idp->shm_ctime = timer.t_time;
        !           220:        idp->shm_cpid  = SELF->p_pid;
        !           221:        idp->shm_perm.cuid = idp->shm_perm.uid = u.u_uid;
        !           222:        idp->shm_perm.cgid = idp->shm_perm.gid = u.u_gid;
        !           223:        idp->shm_perm.mode = (shmflg & 0777) | IPC_ALLOC;
        !           224:        idp->shm_perm.key  = skey;
        !           225: 
        !           226: #ifdef IPC_PRIVATE
        !           227:        if ( skey == IPC_PRIVATE )
        !           228:                idp->shm_perm.mode |= SHM_DEST;
        !           229: #endif
        !           230: 
        !           231:        return idp - shmids;
        !           232: }

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