/* * Copyright (c) 2003 Matthew Dillon All rights reserved. * cdevsw from kern/kern_conf.c Copyright (c) 1995 Terrence R. Lambert * cdevsw from kern/kern_conf.c Copyright (c) 1995 Julian R. Elishcer, * All rights reserved. * Copyright (c) 1982, 1986, 1991, 1993 * The Regents of the University of California. 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. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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. * * $DragonFly: src/sys/kern/kern_device.c,v 1.18 2006/07/28 02:17:40 dillon Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * system link descriptors identify the command in the * arguments structure. */ #define DDESCNAME(name) __CONCAT(__CONCAT(dev_,name),_desc) #define DEVOP_DESC_INIT(name) \ struct syslink_desc DDESCNAME(name) = { \ __offsetof(struct dev_ops, __CONCAT(d_, name)), \ #name } DEVOP_DESC_INIT(default); DEVOP_DESC_INIT(open); DEVOP_DESC_INIT(close); DEVOP_DESC_INIT(read); DEVOP_DESC_INIT(write); DEVOP_DESC_INIT(ioctl); DEVOP_DESC_INIT(dump); DEVOP_DESC_INIT(psize); DEVOP_DESC_INIT(poll); DEVOP_DESC_INIT(mmap); DEVOP_DESC_INIT(strategy); DEVOP_DESC_INIT(kqfilter); DEVOP_DESC_INIT(clone); /* * Misc default ops */ struct dev_ops dead_dev_ops; struct dev_ops default_dev_ops = { { "null" }, .d_default = NULL, /* must be NULL */ .d_open = noopen, .d_close = noclose, .d_read = noread, .d_write = nowrite, .d_ioctl = noioctl, .d_poll = nopoll, .d_mmap = nommap, .d_strategy = nostrategy, .d_dump = nodump, .d_psize = nopsize, .d_kqfilter = nokqfilter, .d_clone = noclone }; /* * This is used to look-up devices */ static struct dev_ops_link *dev_ops_array[NUMCDEVSW]; /************************************************************************ * GENERAL DEVICE API FUNCTIONS * ************************************************************************/ int dev_dopen(dev_t dev, int oflags, int devtype, struct ucred *cred) { struct dev_open_args ap; ap.a_head.a_desc = &dev_open_desc; ap.a_head.a_dev = dev; ap.a_oflags = oflags; ap.a_devtype = devtype; ap.a_cred = cred; return(dev->si_ops->d_open(&ap)); } int dev_dclose(dev_t dev, int fflag, int devtype) { struct dev_close_args ap; ap.a_head.a_desc = &dev_close_desc; ap.a_head.a_dev = dev; ap.a_fflag = fflag; ap.a_devtype = devtype; return(dev->si_ops->d_close(&ap)); } int dev_dread(dev_t dev, struct uio *uio, int ioflag) { struct dev_read_args ap; int error; ap.a_head.a_desc = &dev_read_desc; ap.a_head.a_dev = dev; ap.a_uio = uio; ap.a_ioflag = ioflag; error = dev->si_ops->d_read(&ap); if (error == 0) dev->si_lastread = time_second; return (error); } int dev_dwrite(dev_t dev, struct uio *uio, int ioflag) { struct dev_write_args ap; int error; dev->si_lastwrite = time_second; ap.a_head.a_desc = &dev_write_desc; ap.a_head.a_dev = dev; ap.a_uio = uio; ap.a_ioflag = ioflag; error = dev->si_ops->d_write(&ap); return (error); } int dev_dioctl(dev_t dev, u_long cmd, caddr_t data, int fflag, struct ucred *cred) { struct dev_ioctl_args ap; ap.a_head.a_desc = &dev_ioctl_desc; ap.a_head.a_dev = dev; ap.a_cmd = cmd; ap.a_data = data; ap.a_fflag = fflag; ap.a_cred = cred; return(dev->si_ops->d_ioctl(&ap)); } int dev_dpoll(dev_t dev, int events) { struct dev_poll_args ap; int error; ap.a_head.a_desc = &dev_poll_desc; ap.a_head.a_dev = dev; ap.a_events = events; error = dev->si_ops->d_poll(&ap); if (error == 0) return(ap.a_events); return (seltrue(dev, events)); } int dev_dmmap(dev_t dev, vm_offset_t offset, int nprot) { struct dev_mmap_args ap; int error; ap.a_head.a_desc = &dev_mmap_desc; ap.a_head.a_dev = dev; ap.a_offset = offset; ap.a_nprot = nprot; error = dev->si_ops->d_mmap(&ap); if (error == 0) return(ap.a_result); return(-1); } int dev_dclone(dev_t dev) { struct dev_clone_args ap; ap.a_head.a_desc = &dev_clone_desc; ap.a_head.a_dev = dev; return (dev->si_ops->d_clone(&ap)); } /* * Core device strategy call, used to issue I/O on a device. There are * two versions, a non-chained version and a chained version. The chained * version reuses a BIO set up by vn_strategy(). The only difference is * that, for now, we do not push a new tracking structure when chaining * from vn_strategy. XXX this will ultimately have to change. */ void dev_dstrategy(dev_t dev, struct bio *bio) { struct dev_strategy_args ap; struct bio_track *track; ap.a_head.a_desc = &dev_strategy_desc; ap.a_head.a_dev = dev; ap.a_bio = bio; KKASSERT(bio->bio_track == NULL); KKASSERT(bio->bio_buf->b_cmd != BUF_CMD_DONE); if (bio->bio_buf->b_cmd == BUF_CMD_READ) track = &dev->si_track_read; else track = &dev->si_track_write; atomic_add_int(&track->bk_active, 1); bio->bio_track = track; (void)dev->si_ops->d_strategy(&ap); } void dev_dstrategy_chain(dev_t dev, struct bio *bio) { struct dev_strategy_args ap; KKASSERT(bio->bio_track != NULL); ap.a_head.a_desc = &dev_strategy_desc; ap.a_head.a_dev = dev; ap.a_bio = bio; (void)dev->si_ops->d_strategy(&ap); } /* * note: the disk layer is expected to set count, blkno, and secsize before * forwarding the message. */ int dev_ddump(dev_t dev) { struct dev_dump_args ap; ap.a_head.a_desc = &dev_dump_desc; ap.a_head.a_dev = dev; ap.a_count = 0; ap.a_blkno = 0; ap.a_secsize = 0; return(dev->si_ops->d_dump(&ap)); } int dev_dpsize(dev_t dev) { struct dev_psize_args ap; int error; ap.a_head.a_desc = &dev_psize_desc; ap.a_head.a_dev = dev; error = dev->si_ops->d_psize(&ap); if (error == 0) return (ap.a_result); return(-1); } int dev_dkqfilter(dev_t dev, struct knote *kn) { struct dev_kqfilter_args ap; int error; ap.a_head.a_desc = &dev_kqfilter_desc; ap.a_head.a_dev = dev; ap.a_kn = kn; error = dev->si_ops->d_kqfilter(&ap); if (error == 0) return(ap.a_result); return(ENODEV); } /************************************************************************ * DEVICE HELPER FUNCTIONS * ************************************************************************/ const char * dev_dname(dev_t dev) { return(dev->si_ops->head.name); } int dev_dflags(dev_t dev) { return(dev->si_ops->head.flags); } int dev_dmaj(dev_t dev) { return(dev->si_ops->head.maj); } /* * Used when forwarding a request through layers. The caller adjusts * ap->a_head.a_dev and then calls this function. */ int dev_doperate(struct dev_generic_args *ap) { int (*func)(struct dev_generic_args *); func = *(void **)((char *)ap->a_dev->si_ops + ap->a_desc->sd_offset); return (func(ap)); } /* * Used by the console intercept code only. Issue an operation through * a foreign ops structure allowing the ops structure associated * with the device to remain intact. */ int dev_doperate_ops(struct dev_ops *ops, struct dev_generic_args *ap) { int (*func)(struct dev_generic_args *); func = *(void **)((char *)ops + ap->a_desc->sd_offset); return (func(ap)); } /* * Convert a template dev_ops into the real thing by filling in * uninitialized fields. */ void compile_dev_ops(struct dev_ops *ops) { int offset; for (offset = offsetof(struct dev_ops, dev_ops_first_field); offset <= offsetof(struct dev_ops, dev_ops_last_field); offset += sizeof(void *) ) { void **func_p = (void **)((char *)ops + offset); void **def_p = (void **)((char *)&default_dev_ops + offset); if (*func_p == NULL) { if (ops->d_default) *func_p = ops->d_default; else *func_p = *def_p; } } } /************************************************************************ * MAJOR/MINOR SPACE FUNCTION * ************************************************************************/ /* * This makes a dev_ops entry visible to userland (e.g /dev/). * * The kernel can overload a major number by making multiple dev_ops_add() * calls, but only the most recent one (the first one in the dev_ops_array[] * list matching the mask/match) will be visible to userland. make_dev() does * not automatically call dev_ops_add() (nor do we want it to, since * partition-managed disk devices are overloaded on top of the raw device). * * Disk devices typically register their major, e.g. 'ad0', and then call * into the disk label management code which overloads its own onto e.g. 'ad0' * to support all the various slice and partition combinations. * * The mask/match supplied in this call are a full 32 bits and the same * mask and match must be specified in a later dev_ops_remove() call to * match this add. However, the match value for the minor number should never * have any bits set in the major number's bit range (8-15). The mask value * may be conveniently specified as -1 without creating any major number * interference. */ int dev_ops_add(struct dev_ops *ops, u_int mask, u_int match) { int maj; struct dev_ops_link *link; compile_dev_ops(ops); maj = ops->head.maj; if (maj < 0 || maj >= NUMCDEVSW) { printf("%s: ERROR: driver has bogus dev_ops->head.maj = %d\n", ops->head.name, maj); return (EINVAL); } for (link = dev_ops_array[maj]; link; link = link->next) { /* * If we get an exact match we usurp the target, but we only print * a warning message if a different device switch is installed. */ if (link->mask == mask && link->match == match) { if (link->ops != ops) { printf("WARNING: \"%s\" (%p) is usurping \"%s\"'s" " (%p) dev_ops_array[]\n", ops->head.name, ops, link->ops->head.name, link->ops); link->ops = ops; ++ops->head.refs; } return(0); } /* * XXX add additional warnings for overlaps */ } link = malloc(sizeof(struct dev_ops_link), M_DEVBUF, M_INTWAIT|M_ZERO); link->mask = mask; link->match = match; link->ops = ops; link->next = dev_ops_array[maj]; dev_ops_array[maj] = link; ++ops->head.refs; return(0); } /* * Should only be used by udev2dev(). * * If the minor number is -1, we match the first ops we find for this * major. If the mask is not -1 then multiple minor numbers can match * the same ops. * * Note that this function will return NULL if the minor number is not within * the bounds of the installed mask(s). * * The specified minor number should NOT include any major bits. */ struct dev_ops * dev_ops_get(int x, int y) { struct dev_ops_link *link; if (x < 0 || x >= NUMCDEVSW) return(NULL); for (link = dev_ops_array[x]; link; link = link->next) { if (y == -1 || (link->mask & y) == link->match) return(link->ops); } return(NULL); } /* * Take a cookie cutter to the major/minor device space for the passed * device and generate a new dev_ops visible to userland which the caller * can then modify. The original device is not modified but portions of * its major/minor space will no longer be visible to userland. */ struct dev_ops * dev_ops_add_override(dev_t backing_dev, struct dev_ops *template, u_int mask, u_int match) { struct dev_ops *ops; struct dev_ops *backing_ops = backing_dev->si_ops; ops = malloc(sizeof(struct dev_ops), M_DEVBUF, M_INTWAIT); *ops = *template; ops->head.name = backing_ops->head.name; ops->head.maj = backing_ops->head.maj; ops->head.flags = backing_ops->head.flags; compile_dev_ops(ops); dev_ops_add(ops, mask, match); return(ops); } /* * Remove all matching dev_ops entries from the dev_ops_array[] major * array so no new user opens can be performed, and destroy all devices * installed in the hash table that are associated with this dev_ops. (see * destroy_all_devs()). * * The mask and match should match a previous call to dev_ops_add*(). */ int dev_ops_remove(struct dev_ops *ops, u_int mask, u_int match) { int maj = ops->head.maj; struct dev_ops_link *link; struct dev_ops_link **plink; if (maj < 0 || maj >= NUMCDEVSW) { printf("%s: ERROR: driver has bogus ops->d_maj = %d\n", ops->head.name, maj); return EINVAL; } if (ops != &dead_dev_ops) destroy_all_devs(ops, mask, match); for (plink = &dev_ops_array[maj]; (link = *plink) != NULL; plink = &link->next) { if (link->mask == mask && link->match == match) { if (link->ops == ops) break; printf("%s: ERROR: cannot remove from dev_ops_array[], " "its major number %d was stolen by %s\n", ops->head.name, maj, link->ops->head.name ); } } if (link == NULL) { printf("%s(%d)[%08x/%08x]: WARNING: ops removed " "multiple times!\n", ops->head.name, maj, mask, match); } else { *plink = link->next; --ops->head.refs; /* XXX ops_release() / record refs */ free(link, M_DEVBUF); } if (dev_ops_array[maj] == NULL && ops->head.refs != 0) { printf("%s(%d)[%08x/%08x]: Warning: dev_ops_remove() called " "while %d device refs still exist!\n", ops->head.name, maj, mask, match, ops->head.refs); } else { printf("%s: ops removed\n", ops->head.name); } return 0; } /* * Release a ops entry. When the ref count reaches zero, recurse * through the stack. */ void dev_ops_release(struct dev_ops *ops) { --ops->head.refs; if (ops->head.refs == 0) { /* XXX */ } } struct dev_ops * dev_ops_intercept(dev_t dev, struct dev_ops *iops) { struct dev_ops *oops = dev->si_ops; compile_dev_ops(iops); iops->head.maj = oops->head.maj; iops->head.data = oops->head.data; iops->head.flags = oops->head.flags; dev->si_ops = iops; return (oops); } void dev_ops_restore(dev_t dev, struct dev_ops *oops) { struct dev_ops *iops = dev->si_ops; dev->si_ops = oops; iops->head.maj = 0; iops->head.data = NULL; iops->head.flags = 0; } /************************************************************************ * DEFAULT DEV OPS FUNCTIONS * ************************************************************************/ /* * Unsupported devswitch functions (e.g. for writing to read-only device). * XXX may belong elsewhere. */ int noclone(struct dev_clone_args *ap) { /* take no action */ return (0); /* allow the clone */ } int noopen(struct dev_open_args *ap) { return (ENODEV); } int noclose(struct dev_close_args *ap) { return (ENODEV); } int noread(struct dev_read_args *ap) { return (ENODEV); } int nowrite(struct dev_write_args *ap) { return (ENODEV); } int noioctl(struct dev_ioctl_args *ap) { return (ENODEV); } int nokqfilter(struct dev_kqfilter_args *ap) { return (ENODEV); } int nommap(struct dev_mmap_args *ap) { return (ENODEV); } int nopoll(struct dev_poll_args *ap) { ap->a_events = 0; return(0); } int nostrategy(struct dev_strategy_args *ap) { struct bio *bio = ap->a_bio; bio->bio_buf->b_flags |= B_ERROR; bio->bio_buf->b_error = EOPNOTSUPP; biodone(bio); return(0); } int nopsize(struct dev_psize_args *ap) { ap->a_result = 0; return(0); } int nodump(struct dev_dump_args *ap) { return (ENODEV); } /* * XXX this is probably bogus. Any device that uses it isn't checking the * minor number. */ int nullopen(struct dev_open_args *ap) { return (0); } int nullclose(struct dev_close_args *ap) { return (0); }