/* $OpenBSD: kern_lkm.c,v 1.3 1996/04/21 22:27:01 deraadt Exp $ */ /* $NetBSD: kern_lkm.c,v 1.31 1996/03/31 21:40:27 christos Exp $ */ /* * Copyright (c) 1994 Christopher G. Demetriou * 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. */ /* * XXX it's not really safe to unload *any* of the types which are * currently loadable; e.g. you could unload a syscall which was being * blocked in, etc. In the long term, a solution should be come up * with, but "not right now." -- cgd */ #include #include #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 */ static void lkmunreserve __P((void)); static int _lkm_syscall __P((struct lkm_table *, int)); static int _lkm_vfs __P((struct lkm_table *, int)); static int _lkm_dev __P((struct lkm_table *, int)); #ifdef STREAMS static int _lkm_strmod __P((struct lkm_table *, int)); #endif static int _lkm_exec __P((struct lkm_table *, int)); int lkmexists __P((struct lkm_table *)); int lkmdispatch __P((struct lkm_table *, int)); /*ARGSUSED*/ int 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. */ error = tsleep((caddr_t)&lkm_v, TTIPRI|PCATCH, "lkmopn", 0); if (error) return (error); /* leave LKM_WANT set -- no problem */ } lkm_v |= LKM_ALLOC; return (0); /* pseudo-device open */ } /* * 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 void 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; } int 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*/ int lkmioctl(dev, cmd, data, flag, p) dev_t dev; u_long cmd; caddr_t data; int flag; struct proc *p; { int error = 0; int i; struct lmc_resrv *resrvp; struct lmc_loadbuf *loadbufp; struct lmc_unload *unloadp; struct lmc_stat *statp; char istr[MAXLKMNAME]; switch(cmd) { case LMRESERV: /* reserve pages for a module */ if (securelevel > 0) return EPERM; 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) { error = 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%08lx)\n", curp->area); printf("LKM: LMRESERV (adjusted = 0x%08lx)\n", trunc_page(curp->area)); #endif /* DEBUG */ lkm_state = LKMS_RESERVED; break; case LMLOADBUF: /* Copy in; stateful, follows LMRESERV */ if (securelevel > 0) return EPERM; 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) { error = ENOMEM; break; } /* copy in buffer full of data */ error = copyin(loadbufp->data, (caddr_t)curp->area + curp->offset, i); if (error) break; if ((curp->offset + i) < curp->size) { lkm_state = LKMS_LOADING; #ifdef DEBUG printf("LKM: LMLOADBUF (loading @ %ld of %ld, 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 (securelevel > 0) return EPERM; 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 (securelevel > 0) return EPERM; if ((flag & FWRITE) == 0) /* only allow this if writing */ return EPERM; switch (lkm_state) { case LKMS_LOADED: break; case LKMS_LOADING: /* The remainder must be bss, so we clear it */ bzero((caddr_t)curp->area + curp->offset, curp->size - curp->offset); break; default: #ifdef DEBUG printf("lkm_state is %02x\n", lkm_state); #endif /* DEBUG */ return ENXIO; } curp->entry = (int (*) __P((struct lkm_table *, int, int))) (*((long *) (data))); /* call entry(load)... (assigns "private" portion) */ error = (*(curp->entry))(curp, LKM_E_LOAD, LKM_VERSION); if (error) { /* * 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 (securelevel > 0) return EPERM; 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. */ error = copyinstr(unloadp->name, istr, MAXLKMNAME-1, NULL); if (error) 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) { error = EINVAL; break; } curp = &lkmods[i]; if (!curp->used) { error = ENOENT; break; } /* call entry(unload) */ if ((*(curp->entry))(curp, LKM_E_UNLOAD, LKM_VERSION)) { error = 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, (size_t *)0); /* * 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 */ error = ENOENT; break; } } /* * Range check the value; on failure, return EINVAL */ if (i < 0 || i >= MAXLKMS) { error = EINVAL; break; } curp = &lkmods[i]; if (!curp->used) { /* Not found */ error = 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, (size_t *)0); break; default: /* bad ioctl()... */ error = ENOTTY; break; } return (error); } /* * 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. */ int sys_lkmnosys(p, v, retval) struct proc *p; void *v; register_t *retval; { return (sys_nosys(p, v, retval)); } /* * 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()); } /* * A placeholder function for load/unload/stat calls; simply returns zero. * Used where people don't wnat tp specify a special function. */ int lkm_nofunc(lkmtp, cmd) struct lkm_table *lkmtp; int cmd; { return (0); } 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 error = 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 < SYS_MAXSYSCALL; i++) if (sysent[i].sy_call == sys_lkmnosys) break; /* found it! */ /* out of allocable slots? */ if (i == SYS_MAXSYSCALL) { error = ENFILE; break; } } else { /* assign */ if (i < 0 || i >= SYS_MAXSYSCALL) { error = 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 (error); } /* * 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 error = 0; switch(cmd) { case LKM_E_LOAD: /* don't load twice! */ if (lkmexists(lkmtp)) return (EEXIST); /* make sure there's no VFS in the table with this name */ for (i = 0; i < nvfssw; i++) if (vfssw[i] != (struct vfsops *)0 && strncmp(vfssw[i]->vfs_name, args->lkm_vfsops->vfs_name, MFSNAMELEN) == 0) return (EEXIST); /* pick the last available empty slot */ for (i = nvfssw - 1; i >= 0; i--) if (vfssw[i] == (struct vfsops *)0) break; if (i == -1) { /* or if none, punt */ error = EINVAL; break; } /* * Set up file system */ vfssw[i] = args->lkm_vfsops; vfssw[i]->vfs_refcount = 0; /* * Call init function for this VFS... */ (*(vfssw[i]->vfs_init))(); /* done! */ args->lkm_offset = i; /* slot in vfssw[] */ break; case LKM_E_UNLOAD: /* current slot... */ i = args->lkm_offset; if (vfssw[i]->vfs_refcount != 0) return (EBUSY); /* replace current slot contents with old contents */ vfssw[i] = (struct vfsops *)0; break; case LKM_E_STAT: /* no special handling... */ break; } return (error); } /* * 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 error = 0; extern int nblkdev, nchrdev; /* from 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 == (dev_type_open((*))) lkmenodev) break; /* found it! */ /* out of allocable slots? */ if (i == nblkdev) { error = ENFILE; break; } } else { /* assign */ if (i < 0 || i >= nblkdev) { error = 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 == (dev_type_open((*))) lkmenodev) break; /* found it! */ /* out of allocable slots? */ if (i == nchrdev) { error = ENFILE; break; } } else { /* assign */ if (i < 0 || i >= nchrdev) { error = 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: error = 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: error = ENODEV; break; } break; case LKM_E_STAT: /* no special handling... */ break; } return (error); } #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 error = 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 (error); } #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 error = 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) { error = ENFILE; break; } } else { /* assign */ if (i < 0 || i >= nexecs) { error = 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)); /* realize need to recompute max header size */ exec_maxhdrsz = 0; /* 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)); /* realize need to recompute max header size */ exec_maxhdrsz = 0; break; case LKM_E_STAT: /* no special handling... */ break; } return (error); } /* * 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. */ int lkmdispatch(lkmtp, cmd) struct lkm_table *lkmtp; int cmd; { int error = 0; /* default = success */ switch(lkmtp->private.lkm_any->lkm_type) { case LM_SYSCALL: error = _lkm_syscall(lkmtp, cmd); break; case LM_VFS: error = _lkm_vfs(lkmtp, cmd); break; case LM_DEV: error = _lkm_dev(lkmtp, cmd); break; #ifdef STREAMS case LM_STRMOD: { struct lkm_strmod *args = lkmtp->private.lkm_strmod; } break; #endif /* STREAMS */ case LM_EXEC: error = _lkm_exec(lkmtp, cmd); break; case LM_MISC: /* ignore content -- no "misc-specific" procedure */ break; default: error = ENXIO; /* unknown type */ break; } return (error); }