/* * kern_lkm.c * * functions and pseudo-device for loadable kernel modules * * 05 Jun 93 Terry Lambert Release cleanup * 10 Feb 93 Terry Lambert Original * * Copyright (c) 1992 Terrence R. Lambert. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Terrence R. Lambert. * 4. The name Terrence R. Lambert may not be used to endorse or promote * products derived from this software without specific prior written * permission. * * THIS SOFTWARE IS PROVIDED BY TERRENCE R. LAMBERT ``AS IS'' AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE TERRENCE R. LAMBERT BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $Id: kern_lkm.c,v 1.11 1994/01/13 06:24:16 cgd Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define PAGESIZE 1024 /* kmem_alloc() allocation quantum*/ #define LKM_ALLOC 0x01 #define LKM_WANT 0x02 #define LKMS_IDLE 0x00 #define LKMS_RESERVED 0x01 #define LKMS_LOADING 0x02 #define LKMS_LOADED 0x04 #define LKMS_UNLOADING 0x08 static int lkm_v = 0; static int lkm_state = LKMS_IDLE; #ifndef MAXLKMS #define MAXLKMS 20 #endif static struct lkm_table lkmods[ MAXLKMS]; /* table of loaded modules*/ static struct lkm_table *curp; /* global for in-progress ops*/ /*ARGSUSED*/ lkmopen( dev, flag, devtype, p) dev_t dev; int flag; int devtype; struct proc *p; { int error; if( minor( dev) != 0) return( ENXIO); /* bad minor #*/ /* * Use of the loadable kernel module device must be exclusive; we * may try to remove this restriction later, but it's really no * hardship. */ while( lkm_v & LKM_ALLOC) { if( flag & FNONBLOCK) /* don't hang*/ return( EBUSY); lkm_v |= LKM_WANT; /* * Sleep pending unlock; we use tsleep() to allow * an alarm out of the open. */ if( error = tsleep( (caddr_t)&lkm_v, TTIPRI|PCATCH, "LKM", 0)) return( error); /* leave LKM_WANT set -- no problem*/ } lkm_v |= LKM_ALLOC; return( 0); /* pseudo-device open*/ } /* * l k m u n r e s e r v e * * Unreserve the memory associated with the current loaded module; done on * a coerced close of the lkm device (close on premature exit of modload) * or explicitly by modload as a result of a link failure. */ static int lkmunreserve() { if( lkm_state == LKMS_IDLE) return; /* * Actually unreserve the memory */ if (curp && curp->area) { kmem_free( kmem_map, curp->area, curp->size);/**/ curp->area = 0; } lkm_state = LKMS_IDLE; } lkmclose( dev, flag, mode, p) dev_t dev; int flag; int mode; struct proc *p; { if( !( lkm_v & LKM_ALLOC)) { #ifdef DEBUG printf( "LKM: close before open!\n"); #endif /* DEBUG*/ return( EBADF); } /* do this before waking the herd...*/ if( curp && !curp->used) { /* * If we close before setting used, we have aborted * by way of error or by way of close-on-exit from * a premature exit of "modload". */ lkmunreserve(); /* coerce state to LKM_IDLE*/ } lkm_v &= ~LKM_ALLOC; wakeup( (caddr_t)&lkm_v); /* thundering herd "problem" here*/ return( 0); /* pseudo-device closed*/ } /*ARGSUSED*/ lkmioctl( dev, cmd, data, flag) dev_t dev; int cmd; caddr_t data; int flag; { int err = 0; int i; struct lmc_resrv *resrvp; struct lmc_loadbuf *loadbufp; struct lmc_unload *unloadp; struct lmc_stat *statp; int (*funcp)(); char istr[ MAXLKMNAME]; switch( cmd) { case LMRESERV: /* reserve pages for a module*/ if ((flag & FWRITE) == 0) /* only allow this if writing */ return EPERM; resrvp = (struct lmc_resrv *)data; /* * Find a free slot. */ for( i = 0; i < MAXLKMS; i++) { if( !lkmods[ i].used) break; } if( i == MAXLKMS) { err = ENOMEM; /* no slots available*/ break; } curp = &lkmods[ i]; curp->id = i; /* self reference slot offset*/ resrvp->slot = i; /* return slot*/ /* * Get memory for module */ curp->size = resrvp->size; curp->area = kmem_alloc( kmem_map, curp->size);/**/ curp->offset = 0; /* load offset*/ resrvp->addr = curp->area; /* ret kernel addr*/ #ifdef DEBUG printf( "LKM: LMRESERV (actual = 0x%08x)\n", curp->area); printf( "LKM: LMRESERV (adjusted = 0x%08x)\n", trunc_page(curp->area)); #endif /* DEBUG*/ lkm_state = LKMS_RESERVED; break; case LMLOADBUF: /* Copy in; stateful, follows LMRESERV*/ if ((flag & FWRITE) == 0) /* only allow this if writing */ return EPERM; loadbufp = (struct lmc_loadbuf *)data; i = loadbufp->cnt; if( (lkm_state != LKMS_RESERVED && lkm_state != LKMS_LOADING) || i < 0 || i > MODIOBUF || i > curp->size - curp->offset) { err = ENOMEM; break; } /* copy in buffer full of data*/ if( err = copyin( (caddr_t)loadbufp->data, (caddr_t)curp->area + curp->offset, i)) break; if( ( curp->offset + i) < curp->size) { lkm_state = LKMS_LOADING; #ifdef DEBUG printf( "LKM: LMLOADBUF (loading @ %d of %d, i = %d)\n", curp->offset, curp->size, i); #endif /* DEBUG*/ } else { lkm_state = LKMS_LOADED; #ifdef DEBUG printf( "LKM: LMLOADBUF (loaded)\n"); #endif /* DEBUG*/ } curp->offset += i; break; case LMUNRESRV: /* discard reserved pages for a module*/ if ((flag & FWRITE) == 0) /* only allow this if writing */ return EPERM; lkmunreserve(); /* coerce state to LKM_IDLE*/ #ifdef DEBUG printf( "LKM: LMUNRESERV\n"); #endif /* DEBUG*/ break; case LMREADY: /* module loaded: call entry*/ if ((flag & FWRITE) == 0) /* only allow this if writing */ return EPERM; if( lkm_state != LKMS_LOADED) { #ifdef DEBUG printf( "lkm_state is %02x\n", lkm_state); #endif /* DEBUG*/ err = ENXIO; break; } curp->entry = (int (*)()) (*((int *) ( data))); /* call entry(load)... (assigns "private" portion)*/ if( err = (*(curp->entry))( curp, LKM_E_LOAD, LKM_VERSION)) { /* * Module may refuse loading or may have a * version mismatch... */ lkm_state = LKMS_UNLOADING; /* for lkmunreserve*/ lkmunreserve(); /* free memory*/ curp->used = 0; /* free slot*/ break; } curp->used = 1; #ifdef DEBUG printf( "LKM: LMREADY\n"); #endif /* DEBUG*/ lkm_state = LKMS_IDLE; break; case LMUNLOAD: /* unload a module*/ if ((flag & FWRITE) == 0) /* only allow this if writing */ return EPERM; unloadp = (struct lmc_unload *)data; if( ( i = unloadp->id) == -1) { /* unload by name*/ /* * Copy name and lookup id from all loaded * modules. May fail. */ if (err = copyinstr( unloadp->name, istr, MAXLKMNAME-1, NULL)) break; /* * look up id... */ for( i = 0; i < MAXLKMS; i++) { if( !lkmods[ i].used) continue; if( !strcmp( istr, lkmods[ i].private.lkm_any->lkm_name)) break; } } /* * Range check the value; on failure, return EINVAL */ if( i < 0 || i >= MAXLKMS) { err = EINVAL; break; } curp = &lkmods[ i]; /* call entry(unload)*/ if( (*(curp->entry))( curp, LKM_E_UNLOAD, LKM_VERSION)) { err = EBUSY; break; } lkm_state = LKMS_UNLOADING; /* non-idle for lkmunreserve*/ lkmunreserve(); /* free memory*/ curp->used = 0; /* free slot*/ break; case LMSTAT: /* stat a module by id/name*/ /* allow readers and writers to stat */ statp = (struct lmc_stat *)data; if( ( i = statp->id) == -1) { /* stat by name*/ /* * Copy name and lookup id from all loaded * modules. */ copystr( statp->name, istr, MAXLKMNAME-1, NULL); /* * look up id... */ for( i = 0; i < MAXLKMS; i++) { if( !lkmods[ i].used) continue; if( !strcmp( istr, lkmods[ i].private.lkm_any->lkm_name)) break; } if( i == MAXLKMS) { /* Not found*/ err = ENOENT; break; } } /* * Range check the value; on failure, return EINVAL */ if( i < 0 || i >= MAXLKMS) { err = EINVAL; break; } curp = &lkmods[ i]; if( !curp->used) { /* Not found*/ err = ENOENT; break; } /* * Copy out stat information for this module... */ statp->id = curp->id; statp->offset = curp->private.lkm_any->lkm_offset; statp->type = curp->private.lkm_any->lkm_type; statp->area = curp->area; statp->size = curp->size / PAGESIZE; statp->private = (unsigned long)curp->private.lkm_any; statp->ver = curp->private.lkm_any->lkm_ver; copystr( curp->private.lkm_any->lkm_name, statp->name, MAXLKMNAME - 2, NULL); break; default: /* bad ioctl()...*/ err = ENOTTY; break; } return (err); } /*********************************************************************/ /* * l k m n o s y s * * Acts like "nosys" but can be identified in sysent for dynamic call * number assignment for a limited number of calls. * * Place holder for system call slots reserved for loadable modules. */ lkmnosys() { return( nosys()); } /* * l k m e n o d e v * * Acts like "enodev", but can be identified in cdevsw and bdevsw for * dynamic driver major number assignment for a limited number of * drivers. * * Place holder for device switch slots reserved for loadable modules. */ int lkmenodev() { return( enodev()); } /*********************************************************************/ int lkmexists( lkmtp) struct lkm_table *lkmtp; { int i; /* * see if name exists... */ for( i = 0; i < MAXLKMS; i++) { /* * An unused module and the one we are testing are not * considered. */ if( !lkmods[ i].used || &lkmods[ i] == lkmtp) continue; if( !strcmp( lkmtp->private.lkm_any->lkm_name, lkmods[ i].private.lkm_any->lkm_name)) return( 1); /* already loaded...*/ } return( 0); /* module not loaded...*/ } /* * For the loadable system call described by the structure pointed to * by lkmtp, load/unload/stat it depending on the cmd requested. */ static int _lkm_syscall( lkmtp, cmd) struct lkm_table *lkmtp; int cmd; { struct lkm_syscall *args = lkmtp->private.lkm_syscall; int i; int err = 0; extern int nsysent; /* init_sysent.c*/ switch( cmd) { case LKM_E_LOAD: /* don't load twice!*/ if( lkmexists( lkmtp)) return( EEXIST); if( ( i = args->lkm_offset) == -1) { /* auto*/ /* * Search the table looking for a slot... */ for( i = 0; i < nsysent; i++) if( sysent[ i].sy_call == lkmnosys) break; /* found it!*/ /* out of allocable slots?*/ if( i == nsysent) { err = ENFILE; break; } } else { /* assign*/ if( i < 0 || i >= nsysent) { err = EINVAL; break; } } /* save old*/ bcopy( &sysent[ i], &(args->lkm_oldent), sizeof( struct sysent)); /* replace with new*/ bcopy( args->lkm_sysent, &sysent[ i], sizeof( struct sysent)); /* done!*/ args->lkm_offset = i; /* slot in sysent[]*/ break; case LKM_E_UNLOAD: /* current slot...*/ i = args->lkm_offset; /* replace current slot contents with old contents*/ bcopy( &(args->lkm_oldent), &sysent[ i], sizeof( struct sysent)); break; case LKM_E_STAT: /* no special handling...*/ break; } return( err); } /* * For the loadable virtual file system described by the structure pointed * to by lkmtp, load/unload/stat it depending on the cmd requested. */ static int _lkm_vfs( lkmtp, cmd) struct lkm_table *lkmtp; int cmd; { struct lkm_vfs *args = lkmtp->private.lkm_vfs; int i; int err = 0; switch( cmd) { case LKM_E_LOAD: /* don't load twice!*/ if( lkmexists( lkmtp)) return( EEXIST); /* * Currently, the VFS and mount code in 386BSD is malformed; * this means that the per volume file system identifier is * the index into the table rather than the name; this means * that only the file systems already known to 386BSD are * allowable, since all others don't have fixed offsets. * Interestingly, Dell UNIX has this same bug with their VFS * implementation, but generic AT&T SVR4 does not. * * I will correct the VFS code when I get a chance. */ i = args->lkm_offset; if( i < 0 || i > MOUNT_MAXTYPE) { err = EINVAL; break; } if( vfssw[ i] != (struct vfsops *)0) { err = EEXIST; break; } /* * Set up file system */ vfssw[ i] = args->lkm_vfsops; /* * Call init function for this VFS... */ ( *(vfssw[ i]->vfs_init))( args->lkm_flags); /* done!*/ args->lkm_offset = i; /* slot in sysent[]*/ break; case LKM_E_UNLOAD: /* current slot...*/ i = args->lkm_offset; /* replace current slot contents with old contents*/ vfssw[ i] = (struct vfsops *)0; break; case LKM_E_STAT: /* no special handling...*/ break; } return( err); } /* * For the loadable device driver described by the structure pointed to * by lkmtp, load/unload/stat it depending on the cmd requested. */ static int _lkm_dev( lkmtp, cmd) struct lkm_table *lkmtp; int cmd; { struct lkm_dev *args = lkmtp->private.lkm_dev; int i; int err = 0; extern int nblkdev; /* i386/i386/conf.c*/ extern int nchrdev; /* i386/i386/conf.c*/ switch( cmd) { case LKM_E_LOAD: /* don't load twice!*/ if( lkmexists( lkmtp)) return( EEXIST); switch( args->lkm_devtype) { case LM_DT_BLOCK: if( ( i = args->lkm_offset) == -1) { /* auto*/ /* * Search the table looking for a slot... */ for( i = 0; i < nblkdev; i++) if( bdevsw[ i].d_open == lkmenodev) break; /* found it!*/ /* out of allocable slots?*/ if( i == nblkdev) { err = ENFILE; break; } } else { /* assign*/ if( i < 0 || i >= nblkdev) { err = EINVAL; break; } } /* save old*/ bcopy( &bdevsw[ i], &(args->lkm_olddev.bdev), sizeof( struct bdevsw)); /* replace with new*/ bcopy( args->lkm_dev.bdev, &bdevsw[ i], sizeof( struct bdevsw)); /* done!*/ args->lkm_offset = i; /* slot in bdevsw[]*/ break; case LM_DT_CHAR: if( ( i = args->lkm_offset) == -1) { /* auto*/ /* * Search the table looking for a slot... */ for( i = 0; i < nchrdev; i++) if( cdevsw[ i].d_open == lkmenodev) break; /* found it!*/ /* out of allocable slots?*/ if( i == nchrdev) { err = ENFILE; break; } } else { /* assign*/ if( i < 0 || i >= nchrdev) { err = EINVAL; break; } } /* save old*/ bcopy( &cdevsw[ i], &(args->lkm_olddev.cdev), sizeof( struct cdevsw)); /* replace with new*/ bcopy( args->lkm_dev.cdev, &cdevsw[ i], sizeof( struct cdevsw)); /* done!*/ args->lkm_offset = i; /* slot in cdevsw[]*/ break; default: err = ENODEV; break; } break; case LKM_E_UNLOAD: /* current slot...*/ i = args->lkm_offset; switch( args->lkm_devtype) { case LM_DT_BLOCK: /* replace current slot contents with old contents*/ bcopy( &(args->lkm_olddev.bdev), &bdevsw[ i], sizeof( struct bdevsw)); break; case LM_DT_CHAR: /* replace current slot contents with old contents*/ bcopy( &(args->lkm_olddev.cdev), &cdevsw[ i], sizeof( struct cdevsw)); break; default: err = ENODEV; break; } break; case LKM_E_STAT: /* no special handling...*/ break; } return( err); } #ifdef STREAMS /* * For the loadable streams module described by the structure pointed to * by lkmtp, load/unload/stat it depending on the cmd requested. */ static int _lkm_strmod( lkmtp, cmd) struct lkm_table *lkmtp; int cmd; { struct lkm_strmod *args = lkmtp->private.lkm_strmod; int i; int err = 0; switch( cmd) { case LKM_E_LOAD: /* don't load twice!*/ if( lkmexists( lkmtp)) return( EEXIST); break; case LKM_E_UNLOAD: break; case LKM_E_STAT: /* no special handling...*/ break; } return( err); } #endif /* STREAMS*/ /* * For the loadable execution class described by the structure pointed to * by lkmtp, load/unload/stat it depending on the cmd requested. */ static int _lkm_exec( lkmtp, cmd) struct lkm_table *lkmtp; int cmd; { struct lkm_exec *args = lkmtp->private.lkm_exec; int i; int err = 0; switch( cmd) { case LKM_E_LOAD: /* don't load twice!*/ if( lkmexists( lkmtp)) return( EEXIST); if( ( i = args->lkm_offset) == -1) { /* auto*/ /* * Search the table looking for a slot... */ for( i = 0; i < nexecs; i++) if( execsw[ i].es_check == NULL) break; /* found it!*/ /* out of allocable slots?*/ if( i == nexecs) { err = ENFILE; break; } } else { /* assign*/ if( i < 0 || i >= nexecs) { err = EINVAL; break; } } /* save old*/ bcopy( &execsw[ i], &(args->lkm_oldexec), sizeof( struct execsw)); /* replace with new*/ bcopy( args->lkm_exec, &execsw[ i], sizeof( struct execsw)); /* done!*/ args->lkm_offset = i; /* slot in execsw[]*/ break; case LKM_E_UNLOAD: /* current slot...*/ i = args->lkm_offset; /* replace current slot contents with old contents*/ bcopy( &(args->lkm_oldexec), &execsw[i], sizeof( struct execsw)); break; case LKM_E_STAT: /* no special handling...*/ break; } return( err); } /* * This code handles the per-module type "wiring-in" of loadable modules * into existing kernel tables. For "LM_MISC" modules, wiring and unwiring * is assumed to be done in their entry routines internal to the module * itself. */ lkmdispatch( lkmtp, cmd) struct lkm_table *lkmtp; int cmd; { int err = 0; /* default = success*/ switch( lkmtp->private.lkm_any->lkm_type) { case LM_SYSCALL: err = _lkm_syscall( lkmtp, cmd); break; case LM_VFS: err = _lkm_vfs( lkmtp, cmd); break; case LM_DEV: err = _lkm_dev( lkmtp, cmd); break; #ifdef STREAMS case LM_STRMOD: { struct lkm_strmod *args = lkmtp->private.lkm_strmod; } break; #endif /* STREAMS*/ case LM_EXEC: err = _lkm_exec( lkmtp, cmd); break; case LM_MISC: /* ignore content -- no "misc-specific" procedure*/ break; default: err = ENXIO; /* unknown type*/ break; } return( err); }