/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License, Version 1.0 only * (the "License"). You may not use this file except in compliance * with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2004 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #pragma ident "%Z%%M% %I% %E% SMI" /* * Redirecting driver; used to handle workstation console redirection. * * Redirects all I/O through a given device instance to the device designated * as the current target, as given by the vnode associated with the first * entry in the list of redirections for the given device instance. The * implementation assumes that this vnode denotes a STREAMS device; this is * perhaps a bug. * * Supports the SRIOCSREDIR ioctl for designating a new redirection target. * The new target is added to the front of a list of potentially active * designees. Should the device at the front of this list be closed, the new * front entry assumes active duty. (Stated differently, redirection targets * stack, except that it's possible for entries in the interior of the stack * to go away.) * * Supports the SRIOCISREDIR ioctl for inquiring whether the descriptor given * as argument is the current front of the redirection list associated with * the descriptor on which the ioctl was issued. * * Every open instance of this driver corresponds to an instance of the * underlying client driver. If the redirection stack would otherwise become * empty, this device (designated by the wd_vp field of the wcd_data * structure) is implicitly opened and added to the front of the list. Thus, * there's always an active device for handling i/o through an open instance * of this driver. * * XXX: Names -- many of the names in this driver and its companion STREAMS * module still reflect its origins as the workstation console * redirection driver. Ultimately, they should be changed to reflect the * fact that this driver is potentially a general purpose redirection * driver. In the meantime, the driver is still specialized to have a * single client -- the workstation console driver -- and its file name * remains iwscons.c to reflect that specialization. * * Proposed change: "iwscn" becomes either "dr" (for "streams redirecting * driver") or "srm" (for "streams redirecting module"), as appropriate. * * XXX: Add mechanism for notifying a redirectee that it's no longer the * current redirectee? (This in contrast to the current facility for * letting it ask.) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static int iwscninfo(dev_info_t *, ddi_info_cmd_t, void *, void **); static int iwscnattach(dev_info_t *, ddi_attach_cmd_t); static int iwscnopen(dev_t *, int, int, cred_t *); static int iwscnclose(dev_t, int, int, cred_t *); static int iwscnread(dev_t, struct uio *, cred_t *); static int iwscnwrite(dev_t, struct uio *, cred_t *); static int iwscnioctl(dev_t, int, intptr_t, int, cred_t *, int *); static int iwscnpoll(dev_t, short, int, short *, struct pollhead **); /* * Private copy of devinfo pointer; iwscninfo uses it. */ static dev_info_t *iwscn_dip; struct cb_ops iwscn_cb_ops = { iwscnopen, /* open */ iwscnclose, /* close */ nodev, /* strategy */ nodev, /* print */ nodev, /* dump */ iwscnread, /* read */ iwscnwrite, /* write */ iwscnioctl, /* ioctl */ nodev, /* devmap */ nodev, /* mmap */ nodev, /* segmap */ iwscnpoll, /* poll */ ddi_prop_op, /* cb_prop_op */ 0, /* streamtab */ D_NEW|D_MP /* Driver compatibility flag */ }; struct dev_ops iwscn_ops = { DEVO_REV, /* devo_rev, */ 0, /* refcnt */ iwscninfo, /* info */ nulldev, /* identify */ nulldev, /* probe */ iwscnattach, /* attach */ nodev, /* detach */ nodev, /* reset */ &iwscn_cb_ops, /* driver operations */ NULL /* bus operations */ }; static krwlock_t iwscn_lock; /* lock proecting almost everything here */ /* * A read/write lock was used to serialize reads,writes/opens,closes. * Sometime the open would hang due to a pending read. The new lock * iwscn_open_lock and the read lock are held in open to assure a single * instance, while letting concurrent reads/writes to proceed. */ static kmutex_t iwscn_open_lock; /* Serializes opens */ /* * These next two fields, protected by iwscn_lock, pass the data to wcmopen() * from the ioctl SRIOCSREDIR. wcmopen() uses the data only if the thread * matches. This keeps other threads from interfering. */ extern kthread_id_t iwscn_thread; /* thread that is allowed to */ /* push redirm */ extern wcm_data_t *iwscn_wcm_data; /* allocated data for redirm */ /* * Forward declarations of private routines. */ static int srreset(wcd_data_t *, int, cred_t *); static wcrlist_t *srrm(wcrlist_t **, vnode_t *, int); static wcd_data_t *srilookup(minor_t); static wcd_data_t *srialloc(minor_t); static void sridealloc(wcd_data_t *); static wcrlist_t *srpush(wcrlist_t **, vnode_t *); /* * The head of the list of open instances. */ static wcd_data_t *wcddata; /* * Currently, the only client of this driver is the workstation console * driver. Thus, we can get away with hard-wiring a reference to it here. * * To handle multiple clients, the driver must be revised as follows. * 1) Add a registration routine that clients can call to announce * themselves to this driver. The routine should take as arguments the * major device number of the corresponding instantiation of the * redirecting driver and a pointer to its dedvnops ops vector. * 2) Maintain a list (or perhaps hash array) or registered clients, * recording for each the srvnops ops vector and a pointer to the list * of open instances for that client. * 3) Modify the driver entry points to use their dev argument to look up * the proper instantiation, get the list of open instances, and then use * that as they currently use the open instance list. * 4) To allow clients to unload themselves, we probably need an unregister * routine. This routine would have to cope with active open instances. */ extern srvnops_t wscons_srvnops; #include #include #include #include #include #include /* * Module linkage information for the kernel. */ static struct modldrv modldrv = { &mod_driverops, /* Type of module. This one is a pseudo driver */ "Workstation Redirection driver 'iwscn' %I%", &iwscn_ops, /* driver ops */ }; static struct modlinkage modlinkage = { MODREV_1, &modldrv, NULL }; int _init(void) { return (mod_install(&modlinkage)); } int _fini(void) { return (EBUSY); } int _info(struct modinfo *modinfop) { return (mod_info(&modlinkage, modinfop)); } /* * DDI glue routines. */ /*ARGSUSED*/ static int iwscnattach(dev_info_t *devi, ddi_attach_cmd_t cmd) { static char been_here; if (!been_here) { been_here = 1; rw_init(&iwscn_lock, NULL, RW_DEFAULT, NULL); } if (ddi_create_minor_node(devi, "iwscn", S_IFCHR, 0, DDI_PSEUDO, NULL) == DDI_FAILURE) { ddi_remove_minor_node(devi, NULL); return (-1); } iwscn_dip = devi; return (DDI_SUCCESS); } /* ARGSUSED */ static int iwscninfo(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result) { int error; switch (infocmd) { case DDI_INFO_DEVT2DEVINFO: if (iwscn_dip == NULL) { error = DDI_FAILURE; } else { *result = (void *)iwscn_dip; error = DDI_SUCCESS; } break; case DDI_INFO_DEVT2INSTANCE: *result = (void *)0; error = DDI_SUCCESS; break; default: error = DDI_FAILURE; } return (error); } /* ARGSUSED */ static int iwscnopen( dev_t *devp, int flag, int state, /* should be OTYP_CHR */ cred_t *cred) { minor_t unit = getminor(*devp); wcd_data_t *wd; int err = 0; struct wcrlist *wwd; if (state != OTYP_CHR) return (ENXIO); rw_enter(&iwscn_lock, RW_READER); mutex_enter(&iwscn_open_lock); if ((wd = srilookup(unit)) == NULL) { vnode_t *vp; /* * First open for this instance; get a state structure for it. */ wd = srialloc(unit); /* * Call the client driver to obtain a held vnode for the * underlying "real" device instance. * * XXX: There's wired in knowledge of the client driver here. */ err = wscons_srvnops.svn_get(unit, &vp); if (err != 0) { sridealloc(wd); mutex_exit(&iwscn_open_lock); rw_exit(&iwscn_lock); return (err); } wd->wd_vp = vp; } /* * Reinitalize the list if necessary. * * XXX: Is it possible for the list to empty completely while this * instance is still open? If not, this if should be coalesced * with the previous one. */ if (wd->wd_list == NULL) { wcrlist_t *e = srpush(&wd->wd_list, wd->wd_vp); /* * There's no corresponding redirecting module instance for * the underlying device. */ e->wl_data = NULL; } err = srreset(wd, flag, cred); /* * XXX cleanup the sig list. Hook for console driver. */ for (wwd = wd->wd_list; wwd != NULL; wwd = wwd->wl_next) { ASSERT(wwd->wl_vp->v_stream != NULL); str_cn_clean(wwd->wl_vp); } mutex_exit(&iwscn_open_lock); rw_exit(&iwscn_lock); return (err); } /* ARGSUSED */ static int iwscnclose( dev_t dev, int flag, int state, /* should be OTYP_CHR */ cred_t *cred) { wcd_data_t *wd; int err = 0; if (state != OTYP_CHR) return (ENXIO); rw_enter(&iwscn_lock, RW_WRITER); wd = srilookup(getminor(dev)); /* * Remove all outstanding redirections for this instance. */ while (wd->wd_list != NULL) (void) srrm(&wd->wd_list, wd->wd_list->wl_vp, 1); /* * Since this is the _last_ close, it's our last chance to close the * underlying device. (Note that if someone else has the underlying * workstation console device open, we won't get here, since * spec_close will see s_count > 1.) */ while ((wd->wd_wsconsopen != 0) && (!err)) { err = VOP_CLOSE(wd->wd_vp, flag, 1, (offset_t)0, cred); if (!err) wd->wd_wsconsopen--; } if (!err) wd->wd_vp->v_stream = NULL; /* * We don't need the vnode that the client driver gave us any more. * * XXX: There's wired in knowledge of the client driver here. */ wscons_srvnops.svn_rele(wd->wd_unit, wd->wd_vp); sridealloc(wd); rw_exit(&iwscn_lock); return (err); } static int iwscnread(dev_t dev, uio_t *uio, cred_t *cred) { wcd_data_t *wd; int error; rw_enter(&iwscn_lock, RW_READER); wd = srilookup(getminor(dev)); error = strread(wd->wd_list->wl_vp, uio, cred); rw_exit(&iwscn_lock); return (error); } static int iwscnwrite(dev_t dev, uio_t *uio, cred_t *cred) { wcd_data_t *wd; int error; rw_enter(&iwscn_lock, RW_READER); wd = srilookup(getminor(dev)); error = strwrite(wd->wd_list->wl_vp, uio, cred); rw_exit(&iwscn_lock); return (error); } static int iwscnioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cred, int *rvalp) { wcd_data_t *wd; int err = 0; file_t *f; switch (cmd) { case SRIOCSREDIR: { wcrlist_t *wlp; wcm_data_t *mdp; if (!rw_tryenter(&iwscn_lock, RW_WRITER)) { return (EBUSY); } wd = srilookup(getminor(dev)); /* * Find the vnode corresponding to the file descriptor * argument and verify that it names a stream. */ if ((f = getf((int)arg)) == NULL) { err = EBADF; break; } if (f->f_vnode->v_stream == NULL) { err = ENOSTR; releasef((int)arg); break; } /* * allocate the private data for redirmod, and pass it through * a global to wcmopen(). This is all protected by iwscn_lock. */ mdp = kmem_alloc(sizeof (*mdp), KM_SLEEP); iwscn_wcm_data = mdp; iwscn_thread = curthread; /* * Push a new instance of the redirecting module onto the * stream, so that its close routine can notify us when the * overall stream is closed. (In turn, we'll then remove it * from the redirection list.) */ if ((err = VOP_IOCTL(f->f_vnode, I_PUSH, (intptr_t)"redirmod", (FREAD | FKIOCTL), cred, rvalp)) != 0) { iwscn_thread = NULL; kmem_free(mdp, sizeof (*mdp)); releasef((int)arg); break; } iwscn_thread = NULL; /* clear authorization for wcmopen() */ /* * Push it onto the redirection stack. */ wlp = srpush(&wd->wd_list, f->f_vnode); /* * Fill in the redirecting module instance's private data with * information to let it get to our redirection list when its * close routine is called. Cross-link it with the * redirection list entry. */ mdp->wm_wd = wd; mdp->wm_entry = wlp; wlp->wl_data = mdp; releasef((int)arg); break; } case SRIOCISREDIR: rw_enter(&iwscn_lock, RW_READER); wd = srilookup(getminor(dev)); if ((f = getf((int)arg)) == NULL) { err = EBADF; break; } /* * Return value is 1 if the argument descriptor is the current * redirection target, and 0 otherwise. */ *rvalp = (f->f_vnode == wd->wd_list->wl_vp) ? 1 : 0; releasef((int)arg); break; case I_POP: { /* * XXX - This is a big kludge the handles a deadlock case * when we are trying to pop off the redirection * module. Since this should only happen on a close * of the device, and since it hangs the system, just * do not allow a pop of the redirection module to happen. * Popping other modules is allowed. */ struct stdata *stp; char modname[FMNAMESZ + 1] = " "; rw_enter(&iwscn_lock, RW_READER); wd = srilookup(getminor(dev)); (void) strioctl(wd->wd_list->wl_vp, I_LOOK, (intptr_t)modname, flag, K_TO_K, cred, rvalp); if (strcmp("redirmod", modname) == 0) { if ((f = getf((int)arg)) == NULL) { err = EBADF; break; } if ((stp = f->f_vnode->v_stream) == NULL) { err = ENOSTR; releasef((int)arg); break; } if (!(stp->sd_flag & STRCLOSE)) { releasef((int)arg); rw_exit(&iwscn_lock); cmn_err(CE_WARN, "Popping of redirection " "module not allowed"); return (EINVAL); } releasef((int)arg); } /* Process ioctl normally */ err = strioctl(wd->wd_list->wl_vp, cmd, arg, flag, U_TO_K, cred, rvalp); break; } default: rw_enter(&iwscn_lock, RW_READER); wd = srilookup(getminor(dev)); err = strioctl(wd->wd_list->wl_vp, cmd, arg, flag, U_TO_K, cred, rvalp); break; } rw_exit(&iwscn_lock); return (err); } static int iwscnpoll( dev_t dev, short events, int anyyet, short *reventsp, struct pollhead **phpp) { wcd_data_t *wd; int error; rw_enter(&iwscn_lock, RW_READER); wd = srilookup(getminor(dev)); error = strpoll(wd->wd_list->wl_vp->v_stream, events, anyyet, reventsp, phpp); rw_exit(&iwscn_lock); return (error); } /* * Auxiliary routines. */ /* * Additional public interfaces. */ /* * Reset the current workstation console designee to the device denoted by the * wl_vp field of the first entry in the redirection list. Called from * iwscnopen and from the SRIOCSREDIR case of iwscnioctl, in both cases after * the target vp has been set to its new value. */ static int srreset(wcd_data_t *wd, int flag, cred_t *cred) { wcrlist_t *wlp; int err = 0; ASSERT(RW_WRITE_HELD(&iwscn_lock) || MUTEX_HELD(&iwscn_open_lock)); wlp = wd->wd_list; /* first entry */ /* * If we're reverting back to the workstation console, make sure it's * open. */ if (wlp != NULL && wlp->wl_vp == wd->wd_vp) { vnode_t *vp = wd->wd_vp; /* underlying device's vp */ err = VOP_OPEN(&vp, flag, cred); /* * The underlying driver is not allowed to have cloned itself * for this open. */ if (vp != wd->wd_vp) { panic("srreset: Illegal clone"); /*NOTREACHED*/ } if (!err) wd->wd_wsconsopen++; } return (err); } /* * Remove vp from the redirection list rooted at *rwlp, should it be there. * If zap is nonzero, deallocate the entry and remove dangling references to * the it from the corresponding redirecting module instance's wcm_data * structure. * * If the entry doesn't exist upon completion, return NULL; otherwise return a * pointer to it. */ static wcrlist_t * srrm(wcrlist_t **rwlp, vnode_t *vp, int zap) { wcrlist_t **delwlp; wcrlist_t *wlp; wcm_data_t *mdp; ASSERT(RW_WRITE_HELD(&iwscn_lock) || MUTEX_HELD(&iwscn_open_lock)); for (delwlp = rwlp; (wlp = *delwlp) != NULL; delwlp = &wlp->wl_next) if (wlp->wl_vp == vp) break; if (wlp == NULL) return (NULL); *delwlp = wlp->wl_next; if (zap == 0) return (wlp); if (wlp->wl_vp == vp) VN_RELE(vp); /* * Make sure there are no dangling references leading to the entry * from the corresponding redirecting module instance. */ if ((mdp = wlp->wl_data) != NULL) { mdp->wm_wd = NULL; mdp->wm_entry = NULL; } kmem_free(wlp, sizeof (*wlp)); return (NULL); } /* * srpop - remove redirection because the target stream is being closed. * Called from wcmclose(). */ void srpop(wcm_data_t *mdp, int flag, cred_t *cred) { wcd_data_t *ddp; rw_enter(&iwscn_lock, RW_WRITER); if ((ddp = mdp->wm_wd) != NULL) { ASSERT(mdp->wm_entry != NULL); (void) srrm(&ddp->wd_list, mdp->wm_entry->wl_vp, 1); (void) srreset(ddp, flag, cred); } rw_exit(&iwscn_lock); } /* * Routines for allocating, deallocating, and finding wcd_data structures. * * For a given instantiation of the driver, its open instance structures are * linked together into a list, on the assumption that there will never be * enough open instances to make search efficiency a serious concern. */ /* * Look up the instance structure denoted by unit. */ static wcd_data_t * srilookup(minor_t unit) { wcd_data_t *wd = wcddata; ASSERT(RW_LOCK_HELD(&iwscn_lock)); for (; wd != NULL && wd->wd_unit != unit; wd = wd->wd_next) continue; return (wd); } /* * Allocate a wcd_data structure for the instance denoted by unit, link it in * place, and return a pointer to it. If it's already allocated, simply * return a pointer to it. */ static wcd_data_t * srialloc(minor_t unit) { wcd_data_t *wdp; wcd_data_t **wdpp; ASSERT(MUTEX_HELD(&iwscn_open_lock)); for (wdpp = &wcddata; (wdp = *wdpp) != NULL; wdpp = &wdp->wd_next) { if (unit < wdp->wd_unit) break; if (unit == wdp->wd_unit) { /* Already allocated and in place. */ return (wdp); } } /* * wdpp now points to the proper insertion point for unit's * per-instance structure. */ wdp = kmem_zalloc(sizeof (*wdp), KM_SLEEP); wdp->wd_unit = unit; wdp->wd_next = *wdpp; *wdpp = wdp; return (wdp); } /* * Deallocate the wcd_data structure denoted by wd and unlink it from the * list of open instances. */ static void sridealloc(wcd_data_t *wd) { wcd_data_t *wdp; wcd_data_t **wdpp; ASSERT(RW_WRITE_HELD(&iwscn_lock) || MUTEX_HELD(&iwscn_open_lock)); for (wdpp = &wcddata; (wdp = *wdpp) != NULL; wdpp = &wdp->wd_next) if (wd == wdp) break; if (wdp == NULL) { /* * Not there. This should probably be a panic. */ return; } *wdpp = wdp->wd_next; kmem_free(wdp, sizeof (*wdp)); } /* * Push vp onto the redirection list rooted at *wlpp. If it's already there, * move it to the front position. Return a pointer to its list entry. * * N.B.: It is the caller's responsibility to initialize all fields in the * entry other than the wl_next and wl_vp fields. */ static wcrlist_t * srpush(wcrlist_t **wlpp, vnode_t *vp) { wcrlist_t *nwlp; ASSERT(RW_WRITE_HELD(&iwscn_lock) || MUTEX_HELD(&iwscn_open_lock)); if ((nwlp = srrm(wlpp, vp, 0)) == NULL) { nwlp = kmem_zalloc(sizeof (*nwlp), KM_SLEEP); nwlp->wl_vp = vp; /* * The hold will prevent underlying device from closing * while this vnode is still on the redirection list. */ VN_HOLD(vp); } nwlp->wl_next = *wlpp; *wlpp = nwlp; return (nwlp); }