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Annotation of 43BSDReno/sys/kern/uipc_shm.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1988 University of Utah.
        !             3:  * Copyright (c) 1990 The Regents of the University of California.
        !             4:  * All rights reserved.
        !             5:  *
        !             6:  * This code is derived from software contributed to Berkeley by
        !             7:  * the Systems Programming Group of the University of Utah Computer
        !             8:  * Science Department. Originally from University of Wisconsin.
        !             9:  *
        !            10:  * Redistribution is only permitted until one year after the first shipment
        !            11:  * of 4.4BSD by the Regents.  Otherwise, redistribution and use in source and
        !            12:  * binary forms are permitted provided that: (1) source distributions retain
        !            13:  * this entire copyright notice and comment, and (2) distributions including
        !            14:  * binaries display the following acknowledgement:  This product includes
        !            15:  * software developed by the University of California, Berkeley and its
        !            16:  * contributors'' in the documentation or other materials provided with the
        !            17:  * distribution and in all advertising materials mentioning features or use
        !            18:  * of this software.  Neither the name of the University nor the names of
        !            19:  * its contributors may be used to endorse or promote products derived from
        !            20:  * this software without specific prior written permission.
        !            21:  * THIS SOFTWARE IS PROVIDED AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
        !            22:  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
        !            23:  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            24:  *
        !            25:  * from: Utah $Hdr: uipc_shm.c 1.9 89/08/14$
        !            26:  *
        !            27:  *     @(#)uipc_shm.c  7.9 (Berkeley) 6/28/90
        !            28:  */
        !            29: 
        !            30: /*
        !            31:  * System V shared memory routines.
        !            32:  * TEMPORARY, until mmap is in place;
        !            33:  * needed now for HP-UX compatibility and X server (yech!).
        !            34:  */
        !            35: 
        !            36: #ifdef SYSVSHM
        !            37: 
        !            38: #include "machine/pte.h"
        !            39: 
        !            40: #include "param.h"
        !            41: #include "systm.h"
        !            42: #include "user.h"
        !            43: #include "kernel.h"
        !            44: #include "proc.h"
        !            45: #include "vm.h"
        !            46: #include "shm.h"
        !            47: #include "mapmem.h"
        !            48: #include "malloc.h"
        !            49: 
        !            50: #ifdef HPUXCOMPAT
        !            51: #include "../hpux/hpux.h"
        !            52: #endif
        !            53: 
        !            54: int    shmat(), shmctl(), shmdt(), shmget();
        !            55: int    (*shmcalls[])() = { shmat, shmctl, shmdt, shmget };
        !            56: int    shmtot = 0;
        !            57: 
        !            58: int    shmfork(), shmexit();
        !            59: struct mapmemops shmops = { shmfork, (int (*)())0, shmexit, shmexit };
        !            60: 
        !            61: shminit()
        !            62: {
        !            63:        register int i;
        !            64: 
        !            65:        if (shminfo.shmmni > SHMMMNI)
        !            66:                shminfo.shmmni = SHMMMNI;
        !            67:        for (i = 0; i < shminfo.shmmni; i++) {
        !            68:                shmsegs[i].shm_perm.mode = 0;
        !            69:                shmsegs[i].shm_perm.seq = 0;
        !            70:        }
        !            71: }
        !            72: 
        !            73: /*
        !            74:  * Entry point for all SHM calls
        !            75:  */
        !            76: shmsys(p, uap, retval)
        !            77:        struct proc *p;
        !            78:        struct args {
        !            79:                u_int which;
        !            80:        } *uap;
        !            81:        int *retval;
        !            82: {
        !            83: 
        !            84:        if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
        !            85:                return (EINVAL);
        !            86:        return ((*shmcalls[uap->which])(p, &uap[1], retval));
        !            87: }
        !            88: 
        !            89: /*
        !            90:  * Get a shared memory segment
        !            91:  */
        !            92: shmget(p, uap, retval)
        !            93:        struct proc *p;
        !            94:        register struct args {
        !            95:                key_t key;
        !            96:                int size;
        !            97:                int shmflg;
        !            98:        } *uap;
        !            99:        int *retval;
        !           100: {
        !           101:        register struct shmid_ds *shp;
        !           102:        register struct ucred *cred = u.u_cred;
        !           103:        register int i;
        !           104:        int error, size, rval = 0;
        !           105:        caddr_t kva;
        !           106: 
        !           107:        /* look up the specified shm_id */
        !           108:        if (uap->key != IPC_PRIVATE) {
        !           109:                for (i = 0; i < shminfo.shmmni; i++)
        !           110:                        if ((shmsegs[i].shm_perm.mode & SHM_ALLOC) &&
        !           111:                            shmsegs[i].shm_perm.key == uap->key) {
        !           112:                                rval = i;
        !           113:                                break;
        !           114:                        }
        !           115:        } else
        !           116:                i = shminfo.shmmni;
        !           117: 
        !           118:        /* create a new shared segment if necessary */
        !           119:        if (i == shminfo.shmmni) {
        !           120:                if ((uap->shmflg & IPC_CREAT) == 0)
        !           121:                        return (ENOENT);
        !           122:                if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
        !           123:                        return (EINVAL);
        !           124:                for (i = 0; i < shminfo.shmmni; i++)
        !           125:                        if ((shmsegs[i].shm_perm.mode & SHM_ALLOC) == 0) {
        !           126:                                rval = i;
        !           127:                                break;
        !           128:                        }
        !           129:                if (i == shminfo.shmmni)
        !           130:                        return (ENOSPC);
        !           131:                size = clrnd(btoc(uap->size));
        !           132:                if (shmtot + size > shminfo.shmall)
        !           133:                        return (ENOMEM);
        !           134:                shp = &shmsegs[rval];
        !           135:                /*
        !           136:                 * We need to do a couple of things to ensure consistency
        !           137:                 * in case we sleep in malloc().  We mark segment as
        !           138:                 * allocated so that other shmgets() will not allocate it.
        !           139:                 * We mark it as "destroyed" to insure that shmvalid() is
        !           140:                 * false making most operations fail (XXX).  We set the key,
        !           141:                 * so that other shmget()s will fail.
        !           142:                 */
        !           143:                shp->shm_perm.mode = SHM_ALLOC | SHM_DEST;
        !           144:                shp->shm_perm.key = uap->key;
        !           145:                kva = (caddr_t) malloc((u_long)ctob(size), M_SHM, M_WAITOK);
        !           146:                if (kva == NULL) {
        !           147:                        shp->shm_perm.mode = 0;
        !           148:                        return (ENOMEM);
        !           149:                }
        !           150:                if (!claligned(kva))
        !           151:                        panic("shmget: non-aligned memory");
        !           152:                bzero(kva, (u_int)ctob(size));
        !           153:                shmtot += size;
        !           154:                shp->shm_perm.cuid = shp->shm_perm.uid = cred->cr_uid;
        !           155:                shp->shm_perm.cgid = shp->shm_perm.gid = cred->cr_gid;
        !           156:                shp->shm_perm.mode = SHM_ALLOC | (uap->shmflg&0777);
        !           157:                shp->shm_handle = (void *) kvtopte(kva);
        !           158:                shp->shm_segsz = uap->size;
        !           159:                shp->shm_cpid = p->p_pid;
        !           160:                shp->shm_lpid = shp->shm_nattch = 0;
        !           161:                shp->shm_atime = shp->shm_dtime = 0;
        !           162:                shp->shm_ctime = time.tv_sec;
        !           163:        } else {
        !           164:                shp = &shmsegs[rval];
        !           165:                /* XXX: probably not the right thing to do */
        !           166:                if (shp->shm_perm.mode & SHM_DEST)
        !           167:                        return (EBUSY);
        !           168:                if (error = ipcaccess(&shp->shm_perm, uap->shmflg&0777, cred))
        !           169:                        return (error);
        !           170:                if (uap->size && uap->size > shp->shm_segsz)
        !           171:                        return (EINVAL);
        !           172:                if ((uap->shmflg&IPC_CREAT) && (uap->shmflg&IPC_EXCL))
        !           173:                        return (EEXIST);
        !           174:        }
        !           175:        *retval = shp->shm_perm.seq * SHMMMNI + rval;
        !           176:        return (0);
        !           177: }
        !           178: 
        !           179: /*
        !           180:  * Shared memory control
        !           181:  */
        !           182: /* ARGSUSED */
        !           183: shmctl(p, uap, retval)
        !           184:        struct proc *p;
        !           185:        register struct args {
        !           186:                int shmid;
        !           187:                int cmd;
        !           188:                caddr_t buf;
        !           189:        } *uap;
        !           190:        int *retval;
        !           191: {
        !           192:        register struct shmid_ds *shp;
        !           193:        register struct ucred *cred = u.u_cred;
        !           194:        struct shmid_ds sbuf;
        !           195:        int error;
        !           196: 
        !           197:        if (error = shmvalid(uap->shmid))
        !           198:                return (error);
        !           199:        shp = &shmsegs[uap->shmid % SHMMMNI];
        !           200:        switch (uap->cmd) {
        !           201:        case IPC_STAT:
        !           202:                if (error = ipcaccess(&shp->shm_perm, IPC_R, cred))
        !           203:                        return (error);
        !           204:                return (copyout((caddr_t)shp, uap->buf, sizeof(*shp)));
        !           205: 
        !           206:        case IPC_SET:
        !           207:                if (cred->cr_uid && cred->cr_uid != shp->shm_perm.uid &&
        !           208:                    cred->cr_uid != shp->shm_perm.cuid)
        !           209:                        return (EPERM);
        !           210:                if (error = copyin(uap->buf, (caddr_t)&sbuf, sizeof sbuf))
        !           211:                        return (error);
        !           212:                shp->shm_perm.uid = sbuf.shm_perm.uid;
        !           213:                shp->shm_perm.gid = sbuf.shm_perm.gid;
        !           214:                shp->shm_perm.mode = (shp->shm_perm.mode & ~0777)
        !           215:                        | (sbuf.shm_perm.mode & 0777);
        !           216:                shp->shm_ctime = time.tv_sec;
        !           217:                break;
        !           218: 
        !           219:        case IPC_RMID:
        !           220:                if (cred->cr_uid && cred->cr_uid != shp->shm_perm.uid &&
        !           221:                    cred->cr_uid != shp->shm_perm.cuid)
        !           222:                        return (EPERM);
        !           223:                /* set ctime? */
        !           224:                shp->shm_perm.key = IPC_PRIVATE;
        !           225:                shp->shm_perm.mode |= SHM_DEST;
        !           226:                if (shp->shm_nattch <= 0)
        !           227:                        shmfree(shp);
        !           228:                break;
        !           229: 
        !           230: #ifdef HPUXCOMPAT
        !           231:        case SHM_LOCK:
        !           232:        case SHM_UNLOCK:
        !           233:                /* don't really do anything, but make them think we did */
        !           234:                if ((p->p_flag & SHPUX) == 0)
        !           235:                        return (EINVAL);
        !           236:                if (cred->cr_uid && cred->cr_uid != shp->shm_perm.uid &&
        !           237:                    cred->cr_uid != shp->shm_perm.cuid)
        !           238:                        return (EPERM);
        !           239:                break;
        !           240: #endif
        !           241: 
        !           242:        default:
        !           243:                return (EINVAL);
        !           244:        }
        !           245:        return (0);
        !           246: }
        !           247: 
        !           248: /*
        !           249:  * Attach to shared memory segment.
        !           250:  */
        !           251: shmat(p, uap, retval)
        !           252:        struct proc *p;
        !           253:        register struct args {
        !           254:                int     shmid;
        !           255:                caddr_t shmaddr;
        !           256:                int     shmflg;
        !           257:        } *uap;
        !           258:        int *retval;
        !           259: {
        !           260:        register struct shmid_ds *shp;
        !           261:        register int size;
        !           262:        struct mapmem *mp;
        !           263:        caddr_t uva;
        !           264:        int error, prot, shmmapin();
        !           265: 
        !           266:        if (error = shmvalid(uap->shmid))
        !           267:                return (error);
        !           268:        shp = &shmsegs[uap->shmid % SHMMMNI];
        !           269:        if (shp->shm_handle == NULL)
        !           270:                panic("shmat NULL handle");
        !           271:        if (error = ipcaccess(&shp->shm_perm,
        !           272:                        (uap->shmflg&SHM_RDONLY) ? IPC_R : IPC_R|IPC_W, u.u_cred))
        !           273:                return (error);
        !           274:        uva = uap->shmaddr;
        !           275:        if (uva && ((int)uva & (SHMLBA-1))) {
        !           276:                if (uap->shmflg & SHM_RND)
        !           277:                        uva = (caddr_t) ((int)uva & ~(SHMLBA-1));
        !           278:                else
        !           279:                        return (EINVAL);
        !           280:        }
        !           281:        /*
        !           282:         * Make sure user doesn't use more than their fair share
        !           283:         */
        !           284:        size = 0;
        !           285:        for (mp = u.u_mmap; mp; mp = mp->mm_next)
        !           286:                if (mp->mm_ops == &shmops)
        !           287:                        size++;
        !           288:        if (size >= shminfo.shmseg)
        !           289:                return (EMFILE);
        !           290:        /*
        !           291:         * Allocate a mapped memory region descriptor and
        !           292:         * attempt to expand the user page table to allow for region
        !           293:         */
        !           294:        prot = (uap->shmflg & SHM_RDONLY) ? MM_RO : MM_RW;
        !           295: #if defined(hp300)
        !           296:        prot |= MM_CI;
        !           297: #endif
        !           298:        size = ctob(clrnd(btoc(shp->shm_segsz)));
        !           299:        error = mmalloc(p, uap->shmid, &uva, (segsz_t)size, prot, &shmops, &mp);
        !           300:        if (error)
        !           301:                return (error);
        !           302:        if (error = mmmapin(p, mp, shmmapin)) {
        !           303:                (void) mmfree(p, mp);
        !           304:                return (error);
        !           305:        }
        !           306:        /*
        !           307:         * Fill in the remaining fields
        !           308:         */
        !           309:        shp->shm_lpid = p->p_pid;
        !           310:        shp->shm_atime = time.tv_sec;
        !           311:        shp->shm_nattch++;
        !           312:        *retval = (int) uva;
        !           313:        return (0);
        !           314: }
        !           315: 
        !           316: /*
        !           317:  * Detach from shared memory segment.
        !           318:  */
        !           319: /* ARGSUSED */
        !           320: shmdt(p, uap, retval)
        !           321:        struct proc *p;
        !           322:        struct args {
        !           323:                caddr_t shmaddr;
        !           324:        } *uap;
        !           325:        int *retval;
        !           326: {
        !           327:        register struct mapmem *mp;
        !           328: 
        !           329:        for (mp = u.u_mmap; mp; mp = mp->mm_next)
        !           330:                if (mp->mm_ops == &shmops && mp->mm_uva == uap->shmaddr)
        !           331:                        break;
        !           332:        if (mp == MMNIL)
        !           333:                return (EINVAL);
        !           334:        shmsegs[mp->mm_id % SHMMMNI].shm_lpid = p->p_pid;
        !           335:        return (shmufree(p, mp));
        !           336: }
        !           337: 
        !           338: shmmapin(mp, off)
        !           339:        struct mapmem *mp;
        !           340: {
        !           341:        register struct shmid_ds *shp;
        !           342: 
        !           343:        shp = &shmsegs[mp->mm_id % SHMMMNI];
        !           344:        if (off >= ctob(clrnd(btoc(shp->shm_segsz))))
        !           345:                return(-1);
        !           346:        return(((struct pte *)shp->shm_handle)[btop(off)].pg_pfnum);
        !           347: }
        !           348: 
        !           349: /*
        !           350:  * Increment attach count on fork
        !           351:  */
        !           352: /* ARGSUSED */
        !           353: shmfork(mp, ischild)
        !           354:        register struct mapmem *mp;
        !           355: {
        !           356:        if (!ischild)
        !           357:                shmsegs[mp->mm_id % SHMMMNI].shm_nattch++;
        !           358: }
        !           359: 
        !           360: /*
        !           361:  * Detach from shared memory segment on exit (or exec)
        !           362:  */
        !           363: shmexit(mp)
        !           364:        struct mapmem *mp;
        !           365: {
        !           366:        struct proc *p = u.u_procp;             /* XXX */
        !           367: 
        !           368:        return (shmufree(p, mp));
        !           369: }
        !           370: 
        !           371: shmvalid(id)
        !           372:        register int id;
        !           373: {
        !           374:        register struct shmid_ds *shp;
        !           375: 
        !           376:        if (id < 0 || (id % SHMMMNI) >= shminfo.shmmni)
        !           377:                return(EINVAL);
        !           378:        shp = &shmsegs[id % SHMMMNI];
        !           379:        if (shp->shm_perm.seq == (id / SHMMMNI) &&
        !           380:            (shp->shm_perm.mode & (SHM_ALLOC|SHM_DEST)) == SHM_ALLOC)
        !           381:                return(0);
        !           382:        return(EINVAL);
        !           383: }
        !           384: 
        !           385: /*
        !           386:  * Free user resources associated with a shared memory segment
        !           387:  */
        !           388: shmufree(p, mp)
        !           389:        struct proc *p;
        !           390:        struct mapmem *mp;
        !           391: {
        !           392:        register struct shmid_ds *shp;
        !           393:        int error;
        !           394: 
        !           395:        shp = &shmsegs[mp->mm_id % SHMMMNI];
        !           396:        mmmapout(p, mp);
        !           397:        error = mmfree(p, mp);
        !           398:        shp->shm_dtime = time.tv_sec;
        !           399:        if (--shp->shm_nattch <= 0 && (shp->shm_perm.mode & SHM_DEST))
        !           400:                shmfree(shp);
        !           401:        return (error);
        !           402: }
        !           403: 
        !           404: /*
        !           405:  * Deallocate resources associated with a shared memory segment
        !           406:  */
        !           407: shmfree(shp)
        !           408:        register struct shmid_ds *shp;
        !           409: {
        !           410:        caddr_t kva;
        !           411: 
        !           412:        if (shp->shm_handle == NULL)
        !           413:                panic("shmfree");
        !           414:        kva = (caddr_t) ptetokv(shp->shm_handle);
        !           415:        free(kva, M_SHM);
        !           416:        shp->shm_handle = NULL;
        !           417:        shmtot -= clrnd(btoc(shp->shm_segsz));
        !           418:        shp->shm_perm.mode = 0;
        !           419:        /*
        !           420:         * Increment the sequence number to ensure that outstanding
        !           421:         * shmids for this segment will be invalid in the event that
        !           422:         * the segment is reallocated.  Note that shmids must be
        !           423:         * positive as decreed by SVID.
        !           424:         */
        !           425:        shp->shm_perm.seq++;
        !           426:        if ((int)(shp->shm_perm.seq * SHMMMNI) < 0)
        !           427:                shp->shm_perm.seq = 0;
        !           428: }
        !           429: 
        !           430: /*
        !           431:  * XXX This routine would be common to all sysV style IPC
        !           432:  *     (if the others were implemented).
        !           433:  */
        !           434: ipcaccess(ipc, mode, cred)
        !           435:        register struct ipc_perm *ipc;
        !           436:        int mode;
        !           437:        register struct ucred *cred;
        !           438: {
        !           439:        register int m;
        !           440: 
        !           441:        if (cred->cr_uid == 0)
        !           442:                return(0);
        !           443:        /*
        !           444:         * Access check is based on only one of owner, group, public.
        !           445:         * If not owner, then check group.
        !           446:         * If not a member of the group, then check public access.
        !           447:         */
        !           448:        mode &= 0700;
        !           449:        m = ipc->mode;
        !           450:        if (cred->cr_uid != ipc->uid && cred->cr_uid != ipc->cuid) {
        !           451:                m <<= 3;
        !           452:                if (!groupmember(ipc->gid, cred) &&
        !           453:                    !groupmember(ipc->cgid, cred))
        !           454:                        m <<= 3;
        !           455:        }
        !           456:        if ((mode&m) == mode)
        !           457:                return (0);
        !           458:        return (EACCES);
        !           459: }
        !           460: 
        !           461: #endif /* SYSVSHM */

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