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Annotation of Net2/kern/sysv_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 and use in source and binary forms, with or without
        !            11:  * modification, are permitted provided that the following conditions
        !            12:  * are met:
        !            13:  * 1. Redistributions of source code must retain the above copyright
        !            14:  *    notice, this list of conditions and the following disclaimer.
        !            15:  * 2. Redistributions in binary form must reproduce the above copyright
        !            16:  *    notice, this list of conditions and the following disclaimer in the
        !            17:  *    documentation and/or other materials provided with the distribution.
        !            18:  * 3. All advertising materials mentioning features or use of this software
        !            19:  *    must display the following acknowledgement:
        !            20:  *     This product includes software developed by the University of
        !            21:  *     California, Berkeley and its contributors.
        !            22:  * 4. Neither the name of the University nor the names of its contributors
        !            23:  *    may be used to endorse or promote products derived from this software
        !            24:  *    without specific prior written permission.
        !            25:  *
        !            26:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            27:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            28:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            29:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            30:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            31:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            32:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            33:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            34:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            35:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            36:  * SUCH DAMAGE.
        !            37:  *
        !            38:  * from: Utah $Hdr: uipc_shm.c 1.9 89/08/14$
        !            39:  *
        !            40:  *     @(#)sysv_shm.c  7.15 (Berkeley) 5/13/91
        !            41:  */
        !            42: 
        !            43: /*
        !            44:  * System V shared memory routines.
        !            45:  * TEMPORARY, until mmap is in place;
        !            46:  * needed now for HP-UX compatibility and X server (yech!).
        !            47:  */
        !            48: 
        !            49: #ifdef SYSVSHM
        !            50: 
        !            51: #include "param.h"
        !            52: #include "systm.h"
        !            53: #include "kernel.h"
        !            54: #include "proc.h"
        !            55: #include "shm.h"
        !            56: #include "malloc.h"
        !            57: #include "mman.h"
        !            58: #include "vm/vm.h"
        !            59: #include "vm/vm_kern.h"
        !            60: #include "vm/vm_inherit.h"
        !            61: #include "vm/vm_pager.h"
        !            62: 
        !            63: #ifdef HPUXCOMPAT
        !            64: #include "hp300/hpux/hpux.h"
        !            65: #endif
        !            66: 
        !            67: int    shmat(), shmctl(), shmdt(), shmget();
        !            68: int    (*shmcalls[])() = { shmat, shmctl, shmdt, shmget };
        !            69: int    shmtot = 0;
        !            70: 
        !            71: /*
        !            72:  * Per process internal structure for managing segments.
        !            73:  * Each process using shm will have an array of ``shmseg'' of these.
        !            74:  */
        !            75: struct shmdesc {
        !            76:        vm_offset_t     shmd_uva;
        !            77:        int             shmd_id;
        !            78: };
        !            79: 
        !            80: /*
        !            81:  * Per segment internal structure (shm_handle).
        !            82:  */
        !            83: struct shmhandle {
        !            84:        vm_offset_t     shmh_kva;
        !            85:        caddr_t         shmh_id;
        !            86: };
        !            87: 
        !            88: vm_map_t shm_map;      /* address space for shared memory segments */
        !            89: 
        !            90: shminit()
        !            91: {
        !            92:        register int i;
        !            93:        vm_offset_t whocares1, whocares2;
        !            94: 
        !            95:        shm_map = kmem_suballoc(kernel_map, &whocares1, &whocares2,
        !            96:                                shminfo.shmall * NBPG, FALSE);
        !            97:        if (shminfo.shmmni > SHMMMNI)
        !            98:                shminfo.shmmni = SHMMMNI;
        !            99:        for (i = 0; i < shminfo.shmmni; i++) {
        !           100:                shmsegs[i].shm_perm.mode = 0;
        !           101:                shmsegs[i].shm_perm.seq = 0;
        !           102:        }
        !           103: }
        !           104: 
        !           105: /*
        !           106:  * Entry point for all SHM calls
        !           107:  */
        !           108: shmsys(p, uap, retval)
        !           109:        struct proc *p;
        !           110:        struct args {
        !           111:                u_int which;
        !           112:        } *uap;
        !           113:        int *retval;
        !           114: {
        !           115: 
        !           116:        if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
        !           117:                return (EINVAL);
        !           118:        return ((*shmcalls[uap->which])(p, &uap[1], retval));
        !           119: }
        !           120: 
        !           121: /*
        !           122:  * Get a shared memory segment
        !           123:  */
        !           124: shmget(p, uap, retval)
        !           125:        struct proc *p;
        !           126:        register struct args {
        !           127:                key_t key;
        !           128:                int size;
        !           129:                int shmflg;
        !           130:        } *uap;
        !           131:        int *retval;
        !           132: {
        !           133:        register struct shmid_ds *shp;
        !           134:        register struct ucred *cred = p->p_ucred;
        !           135:        register int i;
        !           136:        int error, size, rval = 0;
        !           137:        register struct shmhandle *shmh;
        !           138: 
        !           139:        /* look up the specified shm_id */
        !           140:        if (uap->key != IPC_PRIVATE) {
        !           141:                for (i = 0; i < shminfo.shmmni; i++)
        !           142:                        if ((shmsegs[i].shm_perm.mode & SHM_ALLOC) &&
        !           143:                            shmsegs[i].shm_perm.key == uap->key) {
        !           144:                                rval = i;
        !           145:                                break;
        !           146:                        }
        !           147:        } else
        !           148:                i = shminfo.shmmni;
        !           149: 
        !           150:        /* create a new shared segment if necessary */
        !           151:        if (i == shminfo.shmmni) {
        !           152:                if ((uap->shmflg & IPC_CREAT) == 0)
        !           153:                        return (ENOENT);
        !           154:                if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
        !           155:                        return (EINVAL);
        !           156:                for (i = 0; i < shminfo.shmmni; i++)
        !           157:                        if ((shmsegs[i].shm_perm.mode & SHM_ALLOC) == 0) {
        !           158:                                rval = i;
        !           159:                                break;
        !           160:                        }
        !           161:                if (i == shminfo.shmmni)
        !           162:                        return (ENOSPC);
        !           163:                size = clrnd(btoc(uap->size));
        !           164:                if (shmtot + size > shminfo.shmall)
        !           165:                        return (ENOMEM);
        !           166:                shp = &shmsegs[rval];
        !           167:                /*
        !           168:                 * We need to do a couple of things to ensure consistency
        !           169:                 * in case we sleep in malloc().  We mark segment as
        !           170:                 * allocated so that other shmgets() will not allocate it.
        !           171:                 * We mark it as "destroyed" to insure that shmvalid() is
        !           172:                 * false making most operations fail (XXX).  We set the key,
        !           173:                 * so that other shmget()s will fail.
        !           174:                 */
        !           175:                shp->shm_perm.mode = SHM_ALLOC | SHM_DEST;
        !           176:                shp->shm_perm.key = uap->key;
        !           177:                shmh = (struct shmhandle *)
        !           178:                        malloc(sizeof(struct shmhandle), M_SHM, M_WAITOK);
        !           179:                shmh->shmh_kva = 0;
        !           180:                shmh->shmh_id = (caddr_t)(0xc0000000|rval);     /* XXX */
        !           181:                error = vm_mmap(shm_map, &shmh->shmh_kva, ctob(size),
        !           182:                                VM_PROT_ALL, MAP_ANON, shmh->shmh_id, 0);
        !           183:                if (error) {
        !           184:                        free((caddr_t)shmh, M_SHM);
        !           185:                        shp->shm_perm.mode = 0;
        !           186:                        return(ENOMEM);
        !           187:                }
        !           188:                shp->shm_handle = (void *) shmh;
        !           189:                shmtot += size;
        !           190:                shp->shm_perm.cuid = shp->shm_perm.uid = cred->cr_uid;
        !           191:                shp->shm_perm.cgid = shp->shm_perm.gid = cred->cr_gid;
        !           192:                shp->shm_perm.mode = SHM_ALLOC | (uap->shmflg&0777);
        !           193:                shp->shm_segsz = uap->size;
        !           194:                shp->shm_cpid = p->p_pid;
        !           195:                shp->shm_lpid = shp->shm_nattch = 0;
        !           196:                shp->shm_atime = shp->shm_dtime = 0;
        !           197:                shp->shm_ctime = time.tv_sec;
        !           198:        } else {
        !           199:                shp = &shmsegs[rval];
        !           200:                /* XXX: probably not the right thing to do */
        !           201:                if (shp->shm_perm.mode & SHM_DEST)
        !           202:                        return (EBUSY);
        !           203:                if (error = ipcaccess(&shp->shm_perm, uap->shmflg&0777, cred))
        !           204:                        return (error);
        !           205:                if (uap->size && uap->size > shp->shm_segsz)
        !           206:                        return (EINVAL);
        !           207:                if ((uap->shmflg&IPC_CREAT) && (uap->shmflg&IPC_EXCL))
        !           208:                        return (EEXIST);
        !           209:        }
        !           210:        *retval = shp->shm_perm.seq * SHMMMNI + rval;
        !           211:        return (0);
        !           212: }
        !           213: 
        !           214: /*
        !           215:  * Shared memory control
        !           216:  */
        !           217: /* ARGSUSED */
        !           218: shmctl(p, uap, retval)
        !           219:        struct proc *p;
        !           220:        register struct args {
        !           221:                int shmid;
        !           222:                int cmd;
        !           223:                caddr_t buf;
        !           224:        } *uap;
        !           225:        int *retval;
        !           226: {
        !           227:        register struct shmid_ds *shp;
        !           228:        register struct ucred *cred = p->p_ucred;
        !           229:        struct shmid_ds sbuf;
        !           230:        int error;
        !           231: 
        !           232:        if (error = shmvalid(uap->shmid))
        !           233:                return (error);
        !           234:        shp = &shmsegs[uap->shmid % SHMMMNI];
        !           235:        switch (uap->cmd) {
        !           236:        case IPC_STAT:
        !           237:                if (error = ipcaccess(&shp->shm_perm, IPC_R, cred))
        !           238:                        return (error);
        !           239:                return (copyout((caddr_t)shp, uap->buf, sizeof(*shp)));
        !           240: 
        !           241:        case IPC_SET:
        !           242:                if (cred->cr_uid && cred->cr_uid != shp->shm_perm.uid &&
        !           243:                    cred->cr_uid != shp->shm_perm.cuid)
        !           244:                        return (EPERM);
        !           245:                if (error = copyin(uap->buf, (caddr_t)&sbuf, sizeof sbuf))
        !           246:                        return (error);
        !           247:                shp->shm_perm.uid = sbuf.shm_perm.uid;
        !           248:                shp->shm_perm.gid = sbuf.shm_perm.gid;
        !           249:                shp->shm_perm.mode = (shp->shm_perm.mode & ~0777)
        !           250:                        | (sbuf.shm_perm.mode & 0777);
        !           251:                shp->shm_ctime = time.tv_sec;
        !           252:                break;
        !           253: 
        !           254:        case IPC_RMID:
        !           255:                if (cred->cr_uid && cred->cr_uid != shp->shm_perm.uid &&
        !           256:                    cred->cr_uid != shp->shm_perm.cuid)
        !           257:                        return (EPERM);
        !           258:                /* set ctime? */
        !           259:                shp->shm_perm.key = IPC_PRIVATE;
        !           260:                shp->shm_perm.mode |= SHM_DEST;
        !           261:                if (shp->shm_nattch <= 0)
        !           262:                        shmfree(shp);
        !           263:                break;
        !           264: 
        !           265: #ifdef HPUXCOMPAT
        !           266:        case SHM_LOCK:
        !           267:        case SHM_UNLOCK:
        !           268:                /* don't really do anything, but make them think we did */
        !           269:                if ((p->p_flag & SHPUX) == 0)
        !           270:                        return (EINVAL);
        !           271:                if (cred->cr_uid && cred->cr_uid != shp->shm_perm.uid &&
        !           272:                    cred->cr_uid != shp->shm_perm.cuid)
        !           273:                        return (EPERM);
        !           274:                break;
        !           275: #endif
        !           276: 
        !           277:        default:
        !           278:                return (EINVAL);
        !           279:        }
        !           280:        return (0);
        !           281: }
        !           282: 
        !           283: /*
        !           284:  * Attach to shared memory segment.
        !           285:  */
        !           286: shmat(p, uap, retval)
        !           287:        struct proc *p;
        !           288:        register struct args {
        !           289:                int     shmid;
        !           290:                caddr_t shmaddr;
        !           291:                int     shmflg;
        !           292:        } *uap;
        !           293:        int *retval;
        !           294: {
        !           295:        register struct shmid_ds *shp;
        !           296:        register int size;
        !           297:        caddr_t uva;
        !           298:        int error;
        !           299:        int flags;
        !           300:        vm_prot_t prot;
        !           301:        struct shmdesc *shmd;
        !           302: 
        !           303:        /*
        !           304:         * Allocate descriptors now (before validity check)
        !           305:         * in case malloc() blocks.
        !           306:         */
        !           307:        shmd = (struct shmdesc *)p->p_vmspace->vm_shm;
        !           308:        size = shminfo.shmseg * sizeof(struct shmdesc);
        !           309:        if (shmd == NULL) {
        !           310:                shmd = (struct shmdesc *)malloc(size, M_SHM, M_WAITOK);
        !           311:                bzero((caddr_t)shmd, size);
        !           312:                p->p_vmspace->vm_shm = (caddr_t)shmd;
        !           313:        }
        !           314:        if (error = shmvalid(uap->shmid))
        !           315:                return (error);
        !           316:        shp = &shmsegs[uap->shmid % SHMMMNI];
        !           317:        if (shp->shm_handle == NULL)
        !           318:                panic("shmat NULL handle");
        !           319:        if (error = ipcaccess(&shp->shm_perm,
        !           320:            (uap->shmflg&SHM_RDONLY) ? IPC_R : IPC_R|IPC_W, p->p_ucred))
        !           321:                return (error);
        !           322:        uva = uap->shmaddr;
        !           323:        if (uva && ((int)uva & (SHMLBA-1))) {
        !           324:                if (uap->shmflg & SHM_RND)
        !           325:                        uva = (caddr_t) ((int)uva & ~(SHMLBA-1));
        !           326:                else
        !           327:                        return (EINVAL);
        !           328:        }
        !           329:        /*
        !           330:         * Make sure user doesn't use more than their fair share
        !           331:         */
        !           332:        for (size = 0; size < shminfo.shmseg; size++) {
        !           333:                if (shmd->shmd_uva == 0)
        !           334:                        break;
        !           335:                shmd++;
        !           336:        }
        !           337:        if (size >= shminfo.shmseg)
        !           338:                return (EMFILE);
        !           339:        size = ctob(clrnd(btoc(shp->shm_segsz)));
        !           340:        prot = VM_PROT_READ;
        !           341:        if ((uap->shmflg & SHM_RDONLY) == 0)
        !           342:                prot |= VM_PROT_WRITE;
        !           343:        flags = MAP_ANON|MAP_SHARED;
        !           344:        if (uva)
        !           345:                flags |= MAP_FIXED;
        !           346:        else
        !           347:                uva = (caddr_t)0x1000000;       /* XXX */
        !           348:        error = vm_mmap(&p->p_vmspace->vm_map, &uva, (vm_size_t)size, prot,
        !           349:            flags, ((struct shmhandle *)shp->shm_handle)->shmh_id, 0);
        !           350:        if (error)
        !           351:                return(error);
        !           352:        shmd->shmd_uva = (vm_offset_t)uva;
        !           353:        shmd->shmd_id = uap->shmid;
        !           354:        /*
        !           355:         * Fill in the remaining fields
        !           356:         */
        !           357:        shp->shm_lpid = p->p_pid;
        !           358:        shp->shm_atime = time.tv_sec;
        !           359:        shp->shm_nattch++;
        !           360:        *retval = (int) uva;
        !           361:        return (0);
        !           362: }
        !           363: 
        !           364: /*
        !           365:  * Detach from shared memory segment.
        !           366:  */
        !           367: /* ARGSUSED */
        !           368: shmdt(p, uap, retval)
        !           369:        struct proc *p;
        !           370:        struct args {
        !           371:                caddr_t shmaddr;
        !           372:        } *uap;
        !           373:        int *retval;
        !           374: {
        !           375:        register struct shmdesc *shmd;
        !           376:        register int i;
        !           377: 
        !           378:        shmd = (struct shmdesc *)p->p_vmspace->vm_shm;
        !           379:        for (i = 0; i < shminfo.shmseg; i++, shmd++)
        !           380:                if (shmd->shmd_uva &&
        !           381:                    shmd->shmd_uva == (vm_offset_t)uap->shmaddr)
        !           382:                        break;
        !           383:        if (i == shminfo.shmseg)
        !           384:                return(EINVAL);
        !           385:        shmufree(p, shmd);
        !           386:        shmsegs[shmd->shmd_id % SHMMMNI].shm_lpid = p->p_pid;
        !           387: }
        !           388: 
        !           389: shmfork(p1, p2, isvfork)
        !           390:        struct proc *p1, *p2;
        !           391:        int isvfork;
        !           392: {
        !           393:        register struct shmdesc *shmd;
        !           394:        register int size;
        !           395: 
        !           396:        /*
        !           397:         * Copy parents descriptive information
        !           398:         */
        !           399:        size = shminfo.shmseg * sizeof(struct shmdesc);
        !           400:        shmd = (struct shmdesc *)malloc(size, M_SHM, M_WAITOK);
        !           401:        bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmd, size);
        !           402:        p2->p_vmspace->vm_shm = (caddr_t)shmd;
        !           403:        /*
        !           404:         * Increment reference counts
        !           405:         */
        !           406:        for (size = 0; size < shminfo.shmseg; size++, shmd++)
        !           407:                if (shmd->shmd_uva)
        !           408:                        shmsegs[shmd->shmd_id % SHMMMNI].shm_nattch++;
        !           409: }
        !           410: 
        !           411: shmexit(p)
        !           412:        struct proc *p;
        !           413: {
        !           414:        register struct shmdesc *shmd;
        !           415:        register int i;
        !           416: 
        !           417:        shmd = (struct shmdesc *)p->p_vmspace->vm_shm;
        !           418:        for (i = 0; i < shminfo.shmseg; i++, shmd++)
        !           419:                if (shmd->shmd_uva)
        !           420:                        shmufree(p, shmd);
        !           421:        free((caddr_t)p->p_vmspace->vm_shm, M_SHM);
        !           422:        p->p_vmspace->vm_shm = NULL;
        !           423: }
        !           424: 
        !           425: shmvalid(id)
        !           426:        register int id;
        !           427: {
        !           428:        register struct shmid_ds *shp;
        !           429: 
        !           430:        if (id < 0 || (id % SHMMMNI) >= shminfo.shmmni)
        !           431:                return(EINVAL);
        !           432:        shp = &shmsegs[id % SHMMMNI];
        !           433:        if (shp->shm_perm.seq == (id / SHMMMNI) &&
        !           434:            (shp->shm_perm.mode & (SHM_ALLOC|SHM_DEST)) == SHM_ALLOC)
        !           435:                return(0);
        !           436:        return(EINVAL);
        !           437: }
        !           438: 
        !           439: /*
        !           440:  * Free user resources associated with a shared memory segment
        !           441:  */
        !           442: shmufree(p, shmd)
        !           443:        struct proc *p;
        !           444:        struct shmdesc *shmd;
        !           445: {
        !           446:        register struct shmid_ds *shp;
        !           447: 
        !           448:        shp = &shmsegs[shmd->shmd_id % SHMMMNI];
        !           449:        (void) vm_deallocate(&p->p_vmspace->vm_map, shmd->shmd_uva,
        !           450:                             ctob(clrnd(btoc(shp->shm_segsz))));
        !           451:        shmd->shmd_id = 0;
        !           452:        shmd->shmd_uva = 0;
        !           453:        shp->shm_dtime = time.tv_sec;
        !           454:        if (--shp->shm_nattch <= 0 && (shp->shm_perm.mode & SHM_DEST))
        !           455:                shmfree(shp);
        !           456: }
        !           457: 
        !           458: /*
        !           459:  * Deallocate resources associated with a shared memory segment
        !           460:  */
        !           461: shmfree(shp)
        !           462:        register struct shmid_ds *shp;
        !           463: {
        !           464: 
        !           465:        if (shp->shm_handle == NULL)
        !           466:                panic("shmfree");
        !           467:        /*
        !           468:         * Lose our lingering object reference by deallocating space
        !           469:         * in kernel.  Pager will also be deallocated as a side-effect.
        !           470:         */
        !           471:        vm_deallocate(shm_map,
        !           472:                      ((struct shmhandle *)shp->shm_handle)->shmh_kva,
        !           473:                      ctob(clrnd(btoc(shp->shm_segsz))));
        !           474:        free((caddr_t)shp->shm_handle, M_SHM);
        !           475:        shp->shm_handle = NULL;
        !           476:        shmtot -= clrnd(btoc(shp->shm_segsz));
        !           477:        shp->shm_perm.mode = 0;
        !           478:        /*
        !           479:         * Increment the sequence number to ensure that outstanding
        !           480:         * shmids for this segment will be invalid in the event that
        !           481:         * the segment is reallocated.  Note that shmids must be
        !           482:         * positive as decreed by SVID.
        !           483:         */
        !           484:        shp->shm_perm.seq++;
        !           485:        if ((int)(shp->shm_perm.seq * SHMMMNI) < 0)
        !           486:                shp->shm_perm.seq = 0;
        !           487: }
        !           488: 
        !           489: /*
        !           490:  * XXX This routine would be common to all sysV style IPC
        !           491:  *     (if the others were implemented).
        !           492:  */
        !           493: ipcaccess(ipc, mode, cred)
        !           494:        register struct ipc_perm *ipc;
        !           495:        int mode;
        !           496:        register struct ucred *cred;
        !           497: {
        !           498:        register int m;
        !           499: 
        !           500:        if (cred->cr_uid == 0)
        !           501:                return(0);
        !           502:        /*
        !           503:         * Access check is based on only one of owner, group, public.
        !           504:         * If not owner, then check group.
        !           505:         * If not a member of the group, then check public access.
        !           506:         */
        !           507:        mode &= 0700;
        !           508:        m = ipc->mode;
        !           509:        if (cred->cr_uid != ipc->uid && cred->cr_uid != ipc->cuid) {
        !           510:                m <<= 3;
        !           511:                if (!groupmember(ipc->gid, cred) &&
        !           512:                    !groupmember(ipc->cgid, cred))
        !           513:                        m <<= 3;
        !           514:        }
        !           515:        if ((mode&m) == mode)
        !           516:                return (0);
        !           517:        return (EACCES);
        !           518: }
        !           519: #endif /* SYSVSHM */

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