/*- * Copyright (c) 1999-2002 Poul-Henning Kamp * 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. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage"); /* Built at compile time from sys/conf/majors */ extern unsigned char reserved_majors[256]; /* * This is the number of hash-buckets. Experiements with 'real-life' * udev_t's show that a prime halfway between two powers of two works * best. */ #define DEVT_HASH 83 /* The number of dev_t's we can create before malloc(9) kick in. */ #define DEVT_STASH 50 static struct cdev devt_stash[DEVT_STASH]; static LIST_HEAD(, cdev) dev_hash[DEVT_HASH]; static LIST_HEAD(, cdev) dev_free; static int free_devt; SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, ""); int nullop(void) { return (0); } int eopnotsupp(void) { return (EOPNOTSUPP); } static int enxio(void) { return (ENXIO); } static int enodev(void) { return (ENODEV); } /* Define a dead_cdevsw for use when devices leave unexpectedly. */ #define dead_open (d_open_t *)enxio #define dead_close (d_close_t *)enxio #define dead_read (d_read_t *)enxio #define dead_write (d_write_t *)enxio #define dead_ioctl (d_ioctl_t *)enxio #define dead_poll (d_poll_t *)enodev #define dead_mmap (d_mmap_t *)enodev static void dead_strategy(struct bio *bp) { biofinish(bp, NULL, ENXIO); } #define dead_dump (dumper_t *)enxio #define dead_kqfilter (d_kqfilter_t *)enxio static struct cdevsw dead_cdevsw = { .d_version = D_VERSION, .d_flags = D_NEEDGIANT, /* XXX: does dead_strategy need this ? */ .d_open = dead_open, .d_close = dead_close, .d_read = dead_read, .d_write = dead_write, .d_ioctl = dead_ioctl, .d_poll = dead_poll, .d_mmap = dead_mmap, .d_strategy = dead_strategy, .d_name = "dead", .d_maj = 255, .d_dump = dead_dump, .d_kqfilter = dead_kqfilter }; /* Default methods if driver does not specify method */ #define null_open (d_open_t *)nullop #define null_close (d_close_t *)nullop #define no_read (d_read_t *)enodev #define no_write (d_write_t *)enodev #define no_ioctl (d_ioctl_t *)enodev #define no_mmap (d_mmap_t *)enodev static int no_kqfilter(dev_t dev __unused, struct knote *kn __unused) { return (1); } static void no_strategy(struct bio *bp) { biofinish(bp, NULL, ENODEV); } static int no_poll(dev_t dev __unused, int events, struct thread *td __unused) { /* * Return true for read/write. If the user asked for something * special, return POLLNVAL, so that clients have a way of * determining reliably whether or not the extended * functionality is present without hard-coding knowledge * of specific filesystem implementations. * Stay in sync with vop_nopoll(). */ if (events & ~POLLSTANDARD) return (POLLNVAL); return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); } #define no_dump (dumper_t *)enodev struct cdevsw * devsw(dev_t dev) { if (dev->si_devsw) return (dev->si_devsw); return (&dead_cdevsw); } /* * dev_t and u_dev_t primitives */ int major(dev_t x) { if (x == NODEV) return NOUDEV; return((x->si_udev >> 8) & 0xff); } int minor(dev_t x) { if (x == NODEV) return NOUDEV; return(x->si_udev & 0xffff00ff); } int dev2unit(dev_t x) { int i; if (x == NODEV) return NOUDEV; i = minor(x); return ((i & 0xff) | (i >> 8)); } int unit2minor(int unit) { KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); return ((unit & 0xff) | ((unit << 8) & ~0xffff)); } static dev_t allocdev(void) { static int stashed; struct cdev *si; if (LIST_FIRST(&dev_free)) { si = LIST_FIRST(&dev_free); LIST_REMOVE(si, si_hash); } else if (stashed >= DEVT_STASH) { MALLOC(si, struct cdev *, sizeof(*si), M_DEVT, M_USE_RESERVE | M_ZERO | M_WAITOK); } else { si = devt_stash + stashed++; bzero(si, sizeof *si); si->si_flags |= SI_STASHED; } si->__si_namebuf[0] = '\0'; si->si_name = si->__si_namebuf; LIST_INIT(&si->si_children); TAILQ_INIT(&si->si_snapshots); return (si); } dev_t makedev(int x, int y) { struct cdev *si; udev_t udev; int hash; if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) panic("makedev of NOUDEV"); udev = (x << 8) | y; hash = udev % DEVT_HASH; LIST_FOREACH(si, &dev_hash[hash], si_hash) { if (si->si_udev == udev) return (si); } si = allocdev(); si->si_udev = udev; LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); return (si); } void freedev(dev_t dev) { if (!free_devt) return; if (SLIST_FIRST(&dev->si_hlist)) return; if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) return; LIST_REMOVE(dev, si_hash); if (dev->si_flags & SI_STASHED) { bzero(dev, sizeof(*dev)); dev->si_flags |= SI_STASHED; LIST_INSERT_HEAD(&dev_free, dev, si_hash); } else { FREE(dev, M_DEVT); } } udev_t dev2udev(dev_t x) { if (x == NODEV) return (NOUDEV); return (x->si_udev); } dev_t udev2dev(udev_t x, int b) { if (x == NOUDEV) return (NODEV); switch (b) { case 0: return (makedev(umajor(x), uminor(x))); default: Debugger("udev2dev(...,X)"); return (NODEV); } } int uminor(udev_t dev) { return (dev & 0xffff00ff); } int umajor(udev_t dev) { return ((dev & 0xff00) >> 8); } udev_t makeudev(int x, int y) { return ((x << 8) | y); } static void find_major(struct cdevsw *devsw) { int i; for (i = NUMCDEVSW - 1; i > 0; i--) if (reserved_majors[i] != i) break; KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name)); devsw->d_maj = i; reserved_majors[i] = i; } static void prep_cdevsw(struct cdevsw *devsw) { if (devsw->d_flags & D_TTY) { if (devsw->d_read == NULL) devsw->d_read = ttyread; if (devsw->d_write == NULL) devsw->d_write = ttywrite; if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = ttykqfilter; if (devsw->d_poll == NULL) devsw->d_poll = ttypoll; } if (devsw->d_open == NULL) devsw->d_open = null_open; if (devsw->d_close == NULL) devsw->d_close = null_close; if (devsw->d_read == NULL) devsw->d_read = no_read; if (devsw->d_write == NULL) devsw->d_write = no_write; if (devsw->d_ioctl == NULL) devsw->d_ioctl = no_ioctl; if (devsw->d_poll == NULL) devsw->d_poll = no_poll; if (devsw->d_mmap == NULL) devsw->d_mmap = no_mmap; if (devsw->d_strategy == NULL) devsw->d_strategy = no_strategy; if (devsw->d_dump == NULL) devsw->d_dump = no_dump; if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = no_kqfilter; if (devsw->d_maj == MAJOR_AUTO) { find_major(devsw); } else { if (devsw->d_maj == 256) /* XXX: tty_cons.c is magic */ devsw->d_maj = 0; KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256, ("Invalid major (%d) in make_dev", devsw->d_maj)); if (reserved_majors[devsw->d_maj] != devsw->d_maj) { printf("WARNING: driver \"%s\" used %s %d\n", devsw->d_name, "unreserved major device number", devsw->d_maj); reserved_majors[devsw->d_maj] = devsw->d_maj; } } } dev_t make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, const char *fmt, ...) { dev_t dev; va_list ap; int i; KASSERT((minor & ~0xffff00ff) == 0, ("Invalid minor (0x%x) in make_dev", minor)); prep_cdevsw(devsw); dev = makedev(devsw->d_maj, minor); if (dev->si_flags & SI_CHEAPCLONE && dev->si_flags & SI_NAMED && dev->si_devsw == devsw) { /* * This is allowed as it removes races and generally * simplifies cloning devices. */ return (dev); } if (dev->si_flags & SI_NAMED) { printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n", dev->si_name); panic("don't do that"); } va_start(ap, fmt); i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); if (i > (sizeof dev->__si_namebuf - 1)) { printf("WARNING: Device name truncated! (%s)", dev->__si_namebuf); } va_end(ap); dev->si_devsw = devsw; dev->si_uid = uid; dev->si_gid = gid; dev->si_mode = perms; dev->si_flags |= SI_NAMED; devfs_create(dev); return (dev); } int dev_named(dev_t pdev, const char *name) { dev_t cdev; if (strcmp(devtoname(pdev), name) == 0) return (1); LIST_FOREACH(cdev, &pdev->si_children, si_siblings) if (strcmp(devtoname(cdev), name) == 0) return (1); return (0); } void dev_depends(dev_t pdev, dev_t cdev) { cdev->si_parent = pdev; cdev->si_flags |= SI_CHILD; LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings); } dev_t make_dev_alias(dev_t pdev, const char *fmt, ...) { dev_t dev; va_list ap; int i; dev = allocdev(); dev->si_flags |= SI_ALIAS; dev->si_flags |= SI_NAMED; dev_depends(pdev, dev); va_start(ap, fmt); i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap); if (i > (sizeof dev->__si_namebuf - 1)) { printf("WARNING: Device name truncated! (%s)", dev->__si_namebuf); } va_end(ap); devfs_create(dev); return (dev); } void destroy_dev(dev_t dev) { if (!(dev->si_flags & SI_NAMED)) { printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n", major(dev), minor(dev)); panic("don't do that"); } devfs_destroy(dev); dev->si_flags &= ~SI_NAMED; if (dev->si_flags & SI_CHILD) { LIST_REMOVE(dev, si_siblings); dev->si_flags &= ~SI_CHILD; } while (!LIST_EMPTY(&dev->si_children)) destroy_dev(LIST_FIRST(&dev->si_children)); if (dev->si_flags & SI_CLONELIST) { LIST_REMOVE(dev, si_clone); dev->si_flags &= ~SI_CLONELIST; } dev->si_drv1 = 0; dev->si_drv2 = 0; dev->si_devsw = 0; bzero(&dev->__si_u, sizeof(dev->__si_u)); dev->si_flags &= ~SI_ALIAS; freedev(dev); } const char * devtoname(dev_t dev) { char *p; int mynor; if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { p = dev->si_name; if (devsw(dev)) sprintf(p, "#%s/", devsw(dev)->d_name); else sprintf(p, "#%d/", major(dev)); p += strlen(p); mynor = minor(dev); if (mynor < 0 || mynor > 255) sprintf(p, "%#x", (u_int)mynor); else sprintf(p, "%d", mynor); } return (dev->si_name); } int dev_stdclone(char *name, char **namep, const char *stem, int *unit) { int u, i; i = strlen(stem); if (bcmp(stem, name, i) != 0) return (0); if (!isdigit(name[i])) return (0); u = 0; if (name[i] == '0' && isdigit(name[i+1])) return (0); while (isdigit(name[i])) { u *= 10; u += name[i++] - '0'; } if (u > 0xffffff) return (0); *unit = u; if (namep) *namep = &name[i]; if (name[i]) return (2); return (1); } /* * Helper functions for cloning device drivers. * * The objective here is to make it unnecessary for the device drivers to * use rman or similar to manage their unit number space. Due to the way * we do "on-demand" devices, using rman or other "private" methods * will be very tricky to lock down properly once we lock down this file. * * Instead we give the drivers these routines which puts the dev_t's that * are to be managed on their own list, and gives the driver the ability * to ask for the first free unit number or a given specified unit number. * * In addition these routines support paired devices (pty, nmdm and similar) * by respecting a number of "flag" bits in the minor number. * */ struct clonedevs { LIST_HEAD(,cdev) head; }; int clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, dev_t *dp, u_int extra) { struct clonedevs *cd; dev_t dev, dl, de; int unit, low, u; KASSERT(!(extra & CLONE_UNITMASK), ("Illegal extra bits (0x%x) in clone_create", extra)); KASSERT(*up <= CLONE_UNITMASK, ("Too high unit (0x%x) in clone_create", *up)); if (csw->d_maj == MAJOR_AUTO) find_major(csw); /* if clonedevs have not been initialized, we do it here */ cd = *cdp; if (cd == NULL) { cd = malloc(sizeof *cd, M_DEVBUF, M_WAITOK | M_ZERO); LIST_INIT(&cd->head); *cdp = cd; } /* * Search the list for a lot of things in one go: * A preexisting match is returned immediately. * The lowest free unit number if we are passed -1, and the place * in the list where we should insert that new element. * The place to insert a specified unit number, if applicable * the end of the list. */ unit = *up; low = 0; de = dl = NULL; LIST_FOREACH(dev, &cd->head, si_clone) { u = dev2unit(dev); if (u == (unit | extra)) { *dp = dev; return (0); } if (unit == -1 && u == low) { low++; de = dev; continue; } if (u > unit) { dl = dev; break; } de = dev; } if (unit == -1) unit = low; dev = makedev(csw->d_maj, unit2minor(unit | extra)); KASSERT(!(dev->si_flags & SI_CLONELIST), ("Dev %p should not be on clonelist", dev)); if (dl != NULL) LIST_INSERT_BEFORE(dl, dev, si_clone); else if (de != NULL) LIST_INSERT_AFTER(de, dev, si_clone); else LIST_INSERT_HEAD(&cd->head, dev, si_clone); dev->si_flags |= SI_CLONELIST; *up = unit; return (1); } /* * Kill everything still on the list. The driver should already have * disposed of any softc hung of the dev_t's at this time. */ void clone_cleanup(struct clonedevs **cdp) { dev_t dev, tdev; struct clonedevs *cd; cd = *cdp; if (cd == NULL) return; LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) { KASSERT(dev->si_flags & SI_NAMED, ("Driver has goofed in cloning underways udev %x", dev->si_udev)); destroy_dev(dev); } free(cd, M_DEVBUF); *cdp = NULL; } /* * Helper sysctl for devname(3). We're given a {u}dev_t and return * the name, if any, registered by the device driver. */ static int sysctl_devname(SYSCTL_HANDLER_ARGS) { int error; udev_t ud; dev_t dev; error = SYSCTL_IN(req, &ud, sizeof (ud)); if (error) return (error); if (ud == NOUDEV) return(EINVAL); dev = makedev(umajor(ud), uminor(ud)); if (dev->si_name[0] == '\0') error = ENOENT; else error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1); freedev(dev); return (error); } SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY, NULL, 0, sysctl_devname, "", "devname(3) handler");