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Diffstat (limited to 'usr/src/uts/common/io/inotify.c')
| -rw-r--r-- | usr/src/uts/common/io/inotify.c | 1508 |
1 files changed, 1508 insertions, 0 deletions
diff --git a/usr/src/uts/common/io/inotify.c b/usr/src/uts/common/io/inotify.c new file mode 100644 index 0000000000..c5c7b379e3 --- /dev/null +++ b/usr/src/uts/common/io/inotify.c @@ -0,0 +1,1508 @@ +/* + * This file and its contents are supplied under the terms of the + * Common Development and Distribution License ("CDDL"), version 1.0. + * You may only use this file in accordance with the terms of version + * 1.0 of the CDDL. + * + * A full copy of the text of the CDDL should have accompanied this + * source. A copy of the CDDL is also available via the Internet at + * http://www.illumos.org/license/CDDL. + */ + +/* + * Copyright (c) 2015 Joyent, Inc. All rights reserved. + */ + +/* + * Support for the inotify facility, a Linux-borne facility for asynchronous + * notification of certain events on specified files or directories. Our + * implementation broadly leverages the file event monitoring facility, and + * would actually be quite straightforward were it not for a very serious + * blunder in the inotify interface: in addition to allowing for one to be + * notified on events on a particular file or directory, inotify also allows + * for one to be notified on certain events on files _within_ a watched + * directory -- even though those events have absolutely nothing to do with + * the directory itself. This leads to all sorts of madness because file + * operations are (of course) not undertaken on paths but rather on open + * files -- and the relationships between open files and the paths that resolve + * to those files are neither static nor isomorphic. We implement this + * concept by having _child watches_ when directories are watched with events + * in IN_CHILD_EVENTS. We add child watches when a watch on a directory is + * first added, and we modify those child watches dynamically as files are + * created, deleted, moved into or moved out of the specified directory. This + * mechanism works well, absent hard links. Hard links, unfortunately, break + * this rather badly, and the user is warned that watches on directories that + * have multiple directory entries referring to the same file may behave + * unexpectedly. + */ + +#include <sys/ddi.h> +#include <sys/sunddi.h> +#include <sys/inotify.h> +#include <sys/fem.h> +#include <sys/conf.h> +#include <sys/stat.h> +#include <sys/vfs_opreg.h> +#include <sys/vmem.h> +#include <sys/avl.h> +#include <sys/sysmacros.h> +#include <sys/cyclic.h> +#include <sys/filio.h> + +struct inotify_state; +struct inotify_kevent; + +typedef struct inotify_watch inotify_watch_t; +typedef struct inotify_state inotify_state_t; +typedef struct inotify_kevent inotify_kevent_t; + +struct inotify_watch { + kmutex_t inw_lock; /* lock protecting ref count */ + int inw_refcnt; /* reference count */ + uint8_t inw_zombie:1; /* boolean: is zombie */ + uint8_t inw_fired:1; /* boolean: fired one-shot */ + uint8_t inw_active:1; /* boolean: watch is active */ + uint8_t inw_orphaned:1; /* boolean: orphaned */ + kcondvar_t inw_cv; /* condvar for zombifier */ + uint32_t inw_mask; /* mask of watch */ + int32_t inw_wd; /* watch descriptor */ + vnode_t *inw_vp; /* underlying vnode */ + inotify_watch_t *inw_parent; /* parent, if a child */ + avl_node_t inw_byvp; /* watches by vnode */ + avl_node_t inw_bywd; /* watches by descriptor */ + avl_tree_t inw_children; /* children, if a parent */ + char *inw_name; /* name, if a child */ + list_node_t inw_orphan; /* orphan list */ + cred_t *inw_cred; /* cred, if orphaned */ + inotify_state_t *inw_state; /* corresponding state */ +}; + +struct inotify_kevent { + inotify_kevent_t *ine_next; /* next event in queue */ + struct inotify_event ine_event; /* event (variable size) */ +}; + +#define INOTIFY_EVENT_LENGTH(ev) \ + (sizeof (inotify_kevent_t) + (ev)->ine_event.len) + +struct inotify_state { + kmutex_t ins_lock; /* lock protecting state */ + avl_tree_t ins_byvp; /* watches by vnode */ + avl_tree_t ins_bywd; /* watches by descriptor */ + vmem_t *ins_wds; /* watch identifier arena */ + int ins_maxwatches; /* maximum number of watches */ + int ins_maxevents; /* maximum number of events */ + int ins_nevents; /* current # of events */ + int32_t ins_size; /* total size of events */ + inotify_kevent_t *ins_head; /* head of event queue */ + inotify_kevent_t *ins_tail; /* tail of event queue */ + pollhead_t ins_pollhd; /* poll head */ + kcondvar_t ins_cv; /* condvar for reading */ + list_t ins_orphans; /* orphan list */ + cyclic_id_t ins_cleaner; /* cyclic for cleaning */ + inotify_watch_t *ins_zombies; /* zombie watch list */ + cred_t *ins_cred; /* creator's credentials */ + inotify_state_t *ins_next; /* next state on global list */ +}; + +/* + * Tunables (exported read-only in lx-branded zones via /proc). + */ +int inotify_maxwatches = 8192; /* max watches per instance */ +int inotify_maxevents = 16384; /* max events */ +int inotify_maxinstances = 128; /* max instances per user */ + +/* + * Internal global variables. + */ +static kmutex_t inotify_lock; /* lock protecting state */ +static dev_info_t *inotify_devi; /* device info */ +static fem_t *inotify_femp; /* FEM pointer */ +static vmem_t *inotify_minor; /* minor number arena */ +static void *inotify_softstate; /* softstate pointer */ +static inotify_state_t *inotify_state; /* global list if state */ + +static void inotify_watch_event(inotify_watch_t *, uint64_t, char *); +static void inotify_watch_insert(inotify_watch_t *, vnode_t *, char *); +static void inotify_watch_delete(inotify_watch_t *, uint32_t); +static void inotify_watch_remove(inotify_state_t *state, + inotify_watch_t *watch); + +static int +inotify_fop_close(femarg_t *vf, int flag, int count, offset_t offset, + cred_t *cr, caller_context_t *ct) +{ + inotify_watch_t *watch = vf->fa_fnode->fn_available; + int rval; + + if ((rval = vnext_close(vf, flag, count, offset, cr, ct)) == 0) { + inotify_watch_event(watch, flag & FWRITE ? + IN_CLOSE_WRITE : IN_CLOSE_NOWRITE, NULL); + } + + return (rval); +} + +static int +inotify_fop_create(femarg_t *vf, char *name, vattr_t *vap, vcexcl_t excl, + int mode, vnode_t **vpp, cred_t *cr, int flag, caller_context_t *ct, + vsecattr_t *vsecp) +{ + inotify_watch_t *watch = vf->fa_fnode->fn_available; + int rval; + + if ((rval = vnext_create(vf, name, vap, excl, mode, + vpp, cr, flag, ct, vsecp)) == 0) { + inotify_watch_insert(watch, *vpp, name); + inotify_watch_event(watch, IN_CREATE, name); + } + + return (rval); +} + +static int +inotify_fop_link(femarg_t *vf, vnode_t *svp, char *tnm, cred_t *cr, + caller_context_t *ct, int flags) +{ + inotify_watch_t *watch = vf->fa_fnode->fn_available; + int rval; + + if ((rval = vnext_link(vf, svp, tnm, cr, ct, flags)) == 0) { + inotify_watch_insert(watch, svp, tnm); + inotify_watch_event(watch, IN_CREATE, tnm); + } + + return (rval); +} + +static int +inotify_fop_mkdir(femarg_t *vf, char *name, vattr_t *vap, vnode_t **vpp, + cred_t *cr, caller_context_t *ct, int flags, vsecattr_t *vsecp) +{ + inotify_watch_t *watch = vf->fa_fnode->fn_available; + int rval; + + if ((rval = vnext_mkdir(vf, name, vap, vpp, cr, + ct, flags, vsecp)) == 0) { + inotify_watch_insert(watch, *vpp, name); + inotify_watch_event(watch, IN_CREATE | IN_ISDIR, name); + } + + return (rval); +} + +static int +inotify_fop_open(femarg_t *vf, int mode, cred_t *cr, caller_context_t *ct) +{ + inotify_watch_t *watch = vf->fa_fnode->fn_available; + int rval; + + if ((rval = vnext_open(vf, mode, cr, ct)) == 0) + inotify_watch_event(watch, IN_OPEN, NULL); + + return (rval); +} + +static int +inotify_fop_read(femarg_t *vf, struct uio *uiop, int ioflag, struct cred *cr, + caller_context_t *ct) +{ + inotify_watch_t *watch = vf->fa_fnode->fn_available; + int rval = vnext_read(vf, uiop, ioflag, cr, ct); + inotify_watch_event(watch, IN_ACCESS, NULL); + + return (rval); +} + +static int +inotify_fop_readdir(femarg_t *vf, uio_t *uiop, cred_t *cr, int *eofp, + caller_context_t *ct, int flags) +{ + inotify_watch_t *watch = vf->fa_fnode->fn_available; + int rval = vnext_readdir(vf, uiop, cr, eofp, ct, flags); + inotify_watch_event(watch, IN_ACCESS | IN_ISDIR, NULL); + + return (rval); +} + +int +inotify_fop_remove(femarg_t *vf, char *nm, cred_t *cr, caller_context_t *ct, + int flags) +{ + inotify_watch_t *watch = vf->fa_fnode->fn_available; + int rval; + + if ((rval = vnext_remove(vf, nm, cr, ct, flags)) == 0) + inotify_watch_event(watch, IN_DELETE, nm); + + return (rval); +} + +int +inotify_fop_rmdir(femarg_t *vf, char *nm, vnode_t *cdir, cred_t *cr, + caller_context_t *ct, int flags) +{ + inotify_watch_t *watch = vf->fa_fnode->fn_available; + int rval; + + if ((rval = vnext_rmdir(vf, nm, cdir, cr, ct, flags)) == 0) + inotify_watch_event(watch, IN_DELETE | IN_ISDIR, nm); + + return (rval); +} + +static int +inotify_fop_setattr(femarg_t *vf, vattr_t *vap, int flags, cred_t *cr, + caller_context_t *ct) +{ + inotify_watch_t *watch = vf->fa_fnode->fn_available; + int rval; + + if ((rval = vnext_setattr(vf, vap, flags, cr, ct)) == 0) + inotify_watch_event(watch, IN_ATTRIB, NULL); + + return (rval); +} + +static int +inotify_fop_write(femarg_t *vf, struct uio *uiop, int ioflag, struct cred *cr, + caller_context_t *ct) +{ + inotify_watch_t *watch = vf->fa_fnode->fn_available; + int rval = vnext_write(vf, uiop, ioflag, cr, ct); + inotify_watch_event(watch, IN_MODIFY, NULL); + + return (rval); +} + +static int +inotify_fop_vnevent(femarg_t *vf, vnevent_t vnevent, vnode_t *dvp, char *name, + caller_context_t *ct) +{ + inotify_watch_t *watch = vf->fa_fnode->fn_available; + + switch (vnevent) { + case VE_RENAME_SRC: + inotify_watch_event(watch, IN_MOVE_SELF, NULL); + inotify_watch_delete(watch, IN_MOVE_SELF); + break; + case VE_REMOVE: + /* + * Linux will apparently fire an IN_ATTRIB event when the link + * count changes (including when it drops to 0 on a remove). + * This is merely somewhat odd; what is amazing is that this + * IN_ATTRIB event is not visible on an inotify watch on the + * parent directory. (IN_ATTRIB events are normally sent to + * watches on the parent directory). While it's hard to + * believe that this constitutes desired semantics, ltp + * unfortunately tests this case (if implicitly); in the name + * of bug-for-bug compatibility, we fire IN_ATTRIB iff we are + * explicitly watching the file that has been removed. + */ + if (watch->inw_parent == NULL) + inotify_watch_event(watch, IN_ATTRIB, NULL); + + /*FALLTHROUGH*/ + case VE_RENAME_DEST: + inotify_watch_event(watch, IN_DELETE_SELF, NULL); + inotify_watch_delete(watch, IN_DELETE_SELF); + break; + case VE_RMDIR: + /* + * It seems that IN_ISDIR should really be OR'd in here, but + * Linux doesn't seem to do that in this case; for the sake of + * bug-for-bug compatibility, we don't do it either. + */ + inotify_watch_event(watch, IN_DELETE_SELF, NULL); + inotify_watch_delete(watch, IN_DELETE_SELF); + break; + case VE_CREATE: + inotify_watch_event(watch, IN_MODIFY | IN_ATTRIB, NULL); + break; + case VE_LINK: + inotify_watch_event(watch, IN_ATTRIB, NULL); + break; + case VE_RENAME_SRC_DIR: + inotify_watch_event(watch, IN_MOVED_FROM, name); + break; + case VE_RENAME_DEST_DIR: + if (name == NULL) + name = dvp->v_path; + + inotify_watch_insert(watch, dvp, name); + inotify_watch_event(watch, IN_MOVED_TO, name); + break; + case VE_SUPPORT: + case VE_MOUNTEDOVER: + case VE_TRUNCATE: + break; + } + + return (vnext_vnevent(vf, vnevent, dvp, name, ct)); +} + +const fs_operation_def_t inotify_vnodesrc_template[] = { + VOPNAME_CLOSE, { .femop_close = inotify_fop_close }, + VOPNAME_CREATE, { .femop_create = inotify_fop_create }, + VOPNAME_LINK, { .femop_link = inotify_fop_link }, + VOPNAME_MKDIR, { .femop_mkdir = inotify_fop_mkdir }, + VOPNAME_OPEN, { .femop_open = inotify_fop_open }, + VOPNAME_READ, { .femop_read = inotify_fop_read }, + VOPNAME_READDIR, { .femop_readdir = inotify_fop_readdir }, + VOPNAME_REMOVE, { .femop_remove = inotify_fop_remove }, + VOPNAME_RMDIR, { .femop_rmdir = inotify_fop_rmdir }, + VOPNAME_SETATTR, { .femop_setattr = inotify_fop_setattr }, + VOPNAME_WRITE, { .femop_write = inotify_fop_write }, + VOPNAME_VNEVENT, { .femop_vnevent = inotify_fop_vnevent }, + NULL, NULL +}; + +static int +inotify_watch_cmpwd(inotify_watch_t *lhs, inotify_watch_t *rhs) +{ + if (lhs->inw_wd < rhs->inw_wd) + return (-1); + + if (lhs->inw_wd > rhs->inw_wd) + return (1); + + return (0); +} + +static int +inotify_watch_cmpvp(inotify_watch_t *lhs, inotify_watch_t *rhs) +{ + uintptr_t lvp = (uintptr_t)lhs->inw_vp, rvp = (uintptr_t)rhs->inw_vp; + + if (lvp < rvp) + return (-1); + + if (lvp > rvp) + return (1); + + return (0); +} + +static void +inotify_watch_hold(inotify_watch_t *watch) +{ + mutex_enter(&watch->inw_lock); + VERIFY(watch->inw_refcnt > 0); + watch->inw_refcnt++; + mutex_exit(&watch->inw_lock); +} + +static void +inotify_watch_release(inotify_watch_t *watch) +{ + mutex_enter(&watch->inw_lock); + VERIFY(watch->inw_refcnt > 1); + + if (--watch->inw_refcnt == 1 && watch->inw_zombie) { + /* + * We're down to our last reference; kick anyone that might be + * waiting. + */ + cv_signal(&watch->inw_cv); + } + + mutex_exit(&watch->inw_lock); +} + +static void +inotify_watch_event(inotify_watch_t *watch, uint64_t mask, char *name) +{ + inotify_kevent_t *event, *tail; + inotify_state_t *state = watch->inw_state; + uint32_t wd = watch->inw_wd, cookie = 0, len; + int align = sizeof (uintptr_t) - 1; + boolean_t removal = mask & IN_REMOVAL ? B_TRUE : B_FALSE; + inotify_watch_t *source = watch; + + if (!(mask &= watch->inw_mask) || mask == IN_ISDIR) + return; + + if (watch->inw_parent != NULL) { + /* + * This is an event on the child; if this isn't a valid child + * event, return. Otherwise, we move our watch to be our + * parent (which we know is around because we have a hold on + * it) and continue. + */ + if (!(mask & IN_CHILD_EVENTS)) + return; + + name = watch->inw_name; + watch = watch->inw_parent; + } + + if (!removal) { + mutex_enter(&state->ins_lock); + + if (watch->inw_zombie || + watch->inw_fired || !watch->inw_active) { + mutex_exit(&state->ins_lock); + return; + } + } else { + if (!watch->inw_active) + return; + + VERIFY(MUTEX_HELD(&state->ins_lock)); + } + + /* + * If this is an operation on a directory and it's a child event + * (event if it's not on a child), we specify IN_ISDIR. + */ + if (source->inw_vp->v_type == VDIR && (mask & IN_CHILD_EVENTS)) + mask |= IN_ISDIR; + + if (mask & (IN_MOVED_FROM | IN_MOVED_TO)) + cookie = (uint32_t)curthread->t_did; + + if (state->ins_nevents >= state->ins_maxevents) { + /* + * We're at our maximum number of events -- turn our event + * into an IN_Q_OVERFLOW event, which will be coalesced if + * it's already the tail event. + */ + mask = IN_Q_OVERFLOW; + wd = (uint32_t)-1; + cookie = 0; + len = 0; + } + + if ((tail = state->ins_tail) != NULL && tail->ine_event.wd == wd && + tail->ine_event.mask == mask && tail->ine_event.cookie == cookie && + ((tail->ine_event.len == 0 && len == 0) || + (name != NULL && tail->ine_event.len != 0 && + strcmp(tail->ine_event.name, name) == 0))) { + /* + * This is an implicitly coalesced event; we're done. + */ + if (!removal) + mutex_exit(&state->ins_lock); + return; + } + + if (name != NULL) { + if ((len = strlen(name) + 1) & align) + len += (align + 1) - (len & align); + } else { + len = 0; + } + + event = kmem_zalloc(sizeof (inotify_kevent_t) + len, KM_SLEEP); + event->ine_event.wd = wd; + event->ine_event.mask = (uint32_t)mask; + event->ine_event.cookie = cookie; + event->ine_event.len = len; + + if (name != NULL) + strcpy(event->ine_event.name, name); + + if (tail != NULL) { + tail->ine_next = event; + } else { + VERIFY(state->ins_head == NULL); + state->ins_head = event; + cv_broadcast(&state->ins_cv); + } + + state->ins_tail = event; + state->ins_nevents++; + state->ins_size += sizeof (event->ine_event) + len; + + if (removal) + return; + + if ((watch->inw_mask & IN_ONESHOT) && !watch->inw_fired) { + /* + * If this is a one-shot, we need to remove the watch. (Note + * that this will recurse back into inotify_watch_event() to + * fire the IN_IGNORED event -- but with "removal" set.) + */ + watch->inw_fired = 1; + inotify_watch_remove(state, watch); + } + + mutex_exit(&state->ins_lock); + pollwakeup(&state->ins_pollhd, POLLRDNORM | POLLIN); +} + +/* + * Destroy a watch. By the time we're in here, the watch must have exactly + * one reference. + */ +static void +inotify_watch_destroy(inotify_watch_t *watch) +{ + VERIFY(MUTEX_HELD(&watch->inw_lock)); + + if (watch->inw_name != NULL) + kmem_free(watch->inw_name, strlen(watch->inw_name) + 1); + + kmem_free(watch, sizeof (inotify_watch_t)); +} + +/* + * Zombify a watch. By the time we come in here, it must be true that the + * watch has already been fem_uninstall()'d -- the only reference should be + * in the state's data structure. If we can get away with freeing it, we'll + * do that -- but if the reference count is greater than one due to an active + * vnode operation, we'll put this watch on the zombie list on the state + * structure. + */ +static void +inotify_watch_zombify(inotify_watch_t *watch) +{ + inotify_state_t *state = watch->inw_state; + + VERIFY(MUTEX_HELD(&state->ins_lock)); + VERIFY(!watch->inw_zombie); + + watch->inw_zombie = 1; + + if (watch->inw_parent != NULL) { + inotify_watch_release(watch->inw_parent); + } else { + avl_remove(&state->ins_byvp, watch); + avl_remove(&state->ins_bywd, watch); + vmem_free(state->ins_wds, (void *)(uintptr_t)watch->inw_wd, 1); + watch->inw_wd = -1; + } + + mutex_enter(&watch->inw_lock); + + if (watch->inw_refcnt == 1) { + /* + * There are no operations in flight and there is no way + * for anyone to discover this watch -- we can destroy it. + */ + inotify_watch_destroy(watch); + } else { + /* + * There are operations in flight; we will need to enqueue + * this for later destruction. + */ + watch->inw_parent = state->ins_zombies; + state->ins_zombies = watch; + mutex_exit(&watch->inw_lock); + } +} + +static inotify_watch_t * +inotify_watch_add(inotify_state_t *state, inotify_watch_t *parent, + const char *name, vnode_t *vp, uint32_t mask) +{ + inotify_watch_t *watch; + int err; + + VERIFY(MUTEX_HELD(&state->ins_lock)); + + watch = kmem_zalloc(sizeof (inotify_watch_t), KM_SLEEP); + + watch->inw_vp = vp; + watch->inw_mask = mask; + watch->inw_state = state; + watch->inw_refcnt = 1; + + if (parent == NULL) { + watch->inw_wd = (int)(uintptr_t)vmem_alloc(state->ins_wds, + 1, VM_BESTFIT | VM_SLEEP); + avl_add(&state->ins_byvp, watch); + avl_add(&state->ins_bywd, watch); + + avl_create(&watch->inw_children, + (int(*)(const void *, const void *))inotify_watch_cmpvp, + sizeof (inotify_watch_t), + offsetof(inotify_watch_t, inw_byvp)); + } else { + VERIFY(name != NULL); + inotify_watch_hold(parent); + watch->inw_mask &= IN_CHILD_EVENTS; + watch->inw_parent = parent; + watch->inw_name = kmem_alloc(strlen(name) + 1, KM_SLEEP); + strcpy(watch->inw_name, name); + + avl_add(&parent->inw_children, watch); + } + + /* + * Add our monitor to the vnode. We must not have the watch lock held + * when we do this, as it will immediately hold our watch. + */ + err = fem_install(vp, inotify_femp, watch, OPARGUNIQ, + (void (*)(void *))inotify_watch_hold, + (void (*)(void *))inotify_watch_release); + + VERIFY(err == 0); + + return (watch); +} + +/* + * Remove a (non-child) watch. This is called from either synchronous context + * via inotify_rm_watch() or monitor context via either a vnevent or a + * one-shot. + */ +static void +inotify_watch_remove(inotify_state_t *state, inotify_watch_t *watch) +{ + inotify_watch_t *child; + int err; + + VERIFY(MUTEX_HELD(&state->ins_lock)); + VERIFY(watch->inw_parent == NULL); + + err = fem_uninstall(watch->inw_vp, inotify_femp, watch); + VERIFY(err == 0); + + /* + * If we have children, we're going to remove them all and set them + * all to be zombies. + */ + while ((child = avl_first(&watch->inw_children)) != NULL) { + VERIFY(child->inw_parent == watch); + avl_remove(&watch->inw_children, child); + + err = fem_uninstall(child->inw_vp, inotify_femp, child); + VERIFY(err == 0); + + /* + * If this child watch has been orphaned, remove it from the + * state's list of orphans. + */ + if (child->inw_orphaned) { + list_remove(&state->ins_orphans, child); + crfree(child->inw_cred); + } + + VN_RELE(child->inw_vp); + + /* + * We're down (or should be down) to a single reference to + * this child watch; it's safe to zombify it. + */ + inotify_watch_zombify(child); + } + + inotify_watch_event(watch, IN_IGNORED | IN_REMOVAL, NULL); + VN_RELE(watch->inw_vp); + + /* + * It's now safe to zombify the watch -- we know that the only reference + * can come from operations in flight. + */ + inotify_watch_zombify(watch); +} + +/* + * Delete a watch. Should only be called from VOP context. + */ +static void +inotify_watch_delete(inotify_watch_t *watch, uint32_t event) +{ + inotify_state_t *state = watch->inw_state; + inotify_watch_t cmp = { .inw_vp = watch->inw_vp }, *parent; + int err; + + if (event != IN_DELETE_SELF && !(watch->inw_mask & IN_CHILD_EVENTS)) + return; + + mutex_enter(&state->ins_lock); + + if (watch->inw_zombie) { + mutex_exit(&state->ins_lock); + return; + } + + if ((parent = watch->inw_parent) == NULL) { + if (event == IN_DELETE_SELF) { + /* + * If we're here because we're being deleted and we + * are not a child watch, we need to delete the entire + * watch, children and all. + */ + inotify_watch_remove(state, watch); + } + + mutex_exit(&state->ins_lock); + return; + } else { + if (event == IN_DELETE_SELF && + !(parent->inw_mask & IN_EXCL_UNLINK)) { + /* + * This is a child watch for a file that is being + * removed and IN_EXCL_UNLINK has not been specified; + * indicate that it is orphaned and add it to the list + * of orphans. (This list will be checked by the + * cleaning cyclic to determine when the watch has + * become the only hold on the vnode, at which point + * the watch can be zombified.) Note that we check + * if the watch is orphaned before we orphan it: hard + * links make it possible for VE_REMOVE to be called + * multiple times on the same vnode. (!) + */ + if (!watch->inw_orphaned) { + watch->inw_orphaned = 1; + watch->inw_cred = CRED(); + crhold(watch->inw_cred); + list_insert_head(&state->ins_orphans, watch); + } + + mutex_exit(&state->ins_lock); + return; + } + + if (watch->inw_orphaned) { + /* + * If we're here, a file was orphaned and then later + * moved -- which almost certainly means that hard + * links are on the scene. We choose the orphan over + * the move because we don't want to spuriously + * drop events if we can avoid it. + */ + crfree(watch->inw_cred); + list_remove(&state->ins_orphans, watch); + } + } + + if (avl_find(&parent->inw_children, &cmp, NULL) == NULL) { + /* + * This watch has already been deleted from the parent. + */ + mutex_exit(&state->ins_lock); + return; + } + + avl_remove(&parent->inw_children, watch); + err = fem_uninstall(watch->inw_vp, inotify_femp, watch); + VERIFY(err == 0); + + VN_RELE(watch->inw_vp); + + /* + * It's now safe to zombify the watch -- which won't actually delete + * it as we know that the reference count is greater than 1. + */ + inotify_watch_zombify(watch); + mutex_exit(&state->ins_lock); +} + +/* + * Insert a new child watch. Should only be called from VOP context when + * a child is created in a watched directory. + */ +static void +inotify_watch_insert(inotify_watch_t *watch, vnode_t *vp, char *name) +{ + inotify_state_t *state = watch->inw_state; + inotify_watch_t cmp = { .inw_vp = vp }; + + if (!(watch->inw_mask & IN_CHILD_EVENTS)) + return; + + mutex_enter(&state->ins_lock); + + if (watch->inw_zombie || watch->inw_parent != NULL || vp == NULL) { + mutex_exit(&state->ins_lock); + return; + } + + if (avl_find(&watch->inw_children, &cmp, NULL) != NULL) { + mutex_exit(&state->ins_lock); + return; + } + + VN_HOLD(vp); + watch = inotify_watch_add(state, watch, name, vp, watch->inw_mask); + VERIFY(watch != NULL); + + mutex_exit(&state->ins_lock); +} + + +static int +inotify_add_watch(inotify_state_t *state, vnode_t *vp, uint32_t mask, + int32_t *wdp) +{ + inotify_watch_t *watch, cmp = { .inw_vp = vp }; + uint32_t set; + + set = (mask & (IN_ALL_EVENTS | IN_MODIFIERS)) | IN_UNMASKABLE; + + /* + * Lookup our vnode to determine if we already have a watch on it. + */ + mutex_enter(&state->ins_lock); + + if ((watch = avl_find(&state->ins_byvp, &cmp, NULL)) == NULL) { + /* + * We don't have this watch; allocate a new one, provided that + * we have fewer than our limit. + */ + if (avl_numnodes(&state->ins_bywd) >= state->ins_maxwatches) { + mutex_exit(&state->ins_lock); + return (ENOSPC); + } + + VN_HOLD(vp); + watch = inotify_watch_add(state, NULL, NULL, vp, set); + *wdp = watch->inw_wd; + mutex_exit(&state->ins_lock); + + return (0); + } + + VERIFY(!watch->inw_zombie); + + if (!(mask & IN_MASK_ADD)) { + /* + * Note that if we're resetting our event mask and we're + * transitioning from an event mask that includes child events + * to one that doesn't, there will be potentially some stale + * child watches. This is basically fine: they won't fire, + * and they will correctly be removed when the watch is + * removed. + */ + watch->inw_mask = 0; + } + + watch->inw_mask |= set; + + *wdp = watch->inw_wd; + + mutex_exit(&state->ins_lock); + + return (0); +} + +static int +inotify_add_child(inotify_state_t *state, vnode_t *vp, char *name) +{ + inotify_watch_t *watch, cmp = { .inw_vp = vp }; + vnode_t *cvp; + int err; + + /* + * Verify that the specified child doesn't have a directory component + * within it. + */ + if (strchr(name, '/') != NULL) + return (EINVAL); + + /* + * Lookup the underlying file. Note that this will succeed even if + * we don't have permissions to actually read the file. + */ + if ((err = lookupnameat(name, + UIO_SYSSPACE, NO_FOLLOW, NULL, &cvp, vp)) != 0) { + return (err); + } + + /* + * Use our vnode to find our watch, and then add our child watch to it. + */ + mutex_enter(&state->ins_lock); + + if ((watch = avl_find(&state->ins_byvp, &cmp, NULL)) == NULL) { + /* + * This is unexpected -- it means that we don't have the + * watch that we thought we had. + */ + mutex_exit(&state->ins_lock); + VN_RELE(cvp); + return (ENXIO); + } + + /* + * Now lookup the child vnode in the watch; we'll only add it if it + * isn't already there. + */ + cmp.inw_vp = cvp; + + if (avl_find(&watch->inw_children, &cmp, NULL) != NULL) { + mutex_exit(&state->ins_lock); + VN_RELE(cvp); + return (0); + } + + watch = inotify_watch_add(state, watch, name, cvp, watch->inw_mask); + VERIFY(watch != NULL); + mutex_exit(&state->ins_lock); + + return (0); +} + +static int +inotify_rm_watch(inotify_state_t *state, int32_t wd) +{ + inotify_watch_t *watch, cmp = { .inw_wd = wd }; + + mutex_enter(&state->ins_lock); + + if ((watch = avl_find(&state->ins_bywd, &cmp, NULL)) == NULL) { + mutex_exit(&state->ins_lock); + return (EINVAL); + } + + inotify_watch_remove(state, watch); + mutex_exit(&state->ins_lock); + + return (0); +} + +static int +inotify_activate(inotify_state_t *state, int32_t wd) +{ + inotify_watch_t *watch, cmp = { .inw_wd = wd }; + + mutex_enter(&state->ins_lock); + + if ((watch = avl_find(&state->ins_bywd, &cmp, NULL)) == NULL) { + mutex_exit(&state->ins_lock); + return (EINVAL); + } + + watch->inw_active = 1; + + mutex_exit(&state->ins_lock); + + return (0); +} + +/* + * Called periodically as a cyclic to process the orphans and zombies. + */ +static void +inotify_clean(void *arg) +{ + inotify_state_t *state = arg; + inotify_watch_t *watch, *parent, *next, **prev; + cred_t *savecred; + int err; + + mutex_enter(&state->ins_lock); + + for (watch = list_head(&state->ins_orphans); + watch != NULL; watch = next) { + next = list_next(&state->ins_orphans, watch); + + VERIFY(!watch->inw_zombie); + VERIFY((parent = watch->inw_parent) != NULL); + + if (watch->inw_vp->v_count > 1) + continue; + + avl_remove(&parent->inw_children, watch); + err = fem_uninstall(watch->inw_vp, inotify_femp, watch); + VERIFY(err == 0); + + list_remove(&state->ins_orphans, watch); + + /* + * For purposes of releasing the vnode, we need to switch our + * cred to be the cred of the orphaning thread (which we held + * at the time this watch was orphaned). + */ + savecred = curthread->t_cred; + curthread->t_cred = watch->inw_cred; + VN_RELE(watch->inw_vp); + crfree(watch->inw_cred); + curthread->t_cred = savecred; + + inotify_watch_zombify(watch); + } + + prev = &state->ins_zombies; + + while ((watch = *prev) != NULL) { + mutex_enter(&watch->inw_lock); + + if (watch->inw_refcnt == 1) { + *prev = watch->inw_parent; + inotify_watch_destroy(watch); + continue; + } + + prev = &watch->inw_parent; + mutex_exit(&watch->inw_lock); + } + + mutex_exit(&state->ins_lock); +} + +/*ARGSUSED*/ +static int +inotify_open(dev_t *devp, int flag, int otyp, cred_t *cred_p) +{ + inotify_state_t *state; + major_t major = getemajor(*devp); + minor_t minor = getminor(*devp); + int instances = 0; + cyc_handler_t hdlr; + cyc_time_t when; + char c[64]; + + if (minor != INOTIFYMNRN_INOTIFY) + return (ENXIO); + + mutex_enter(&inotify_lock); + + for (state = inotify_state; state != NULL; state = state->ins_next) { + if (state->ins_cred == cred_p) + instances++; + } + + if (instances >= inotify_maxinstances) { + mutex_exit(&inotify_lock); + return (EMFILE); + } + + minor = (minor_t)(uintptr_t)vmem_alloc(inotify_minor, 1, + VM_BESTFIT | VM_SLEEP); + + if (ddi_soft_state_zalloc(inotify_softstate, minor) != DDI_SUCCESS) { + vmem_free(inotify_minor, (void *)(uintptr_t)minor, 1); + mutex_exit(&inotify_lock); + return (NULL); + } + + state = ddi_get_soft_state(inotify_softstate, minor); + *devp = makedevice(major, minor); + + crhold(cred_p); + state->ins_cred = cred_p; + state->ins_next = inotify_state; + inotify_state = state; + + (void) snprintf(c, sizeof (c), "inotify_watchid_%d", minor); + state->ins_wds = vmem_create(c, (void *)1, UINT32_MAX, 1, + NULL, NULL, NULL, 0, VM_SLEEP | VMC_IDENTIFIER); + + avl_create(&state->ins_bywd, + (int(*)(const void *, const void *))inotify_watch_cmpwd, + sizeof (inotify_watch_t), + offsetof(inotify_watch_t, inw_bywd)); + + avl_create(&state->ins_byvp, + (int(*)(const void *, const void *))inotify_watch_cmpvp, + sizeof (inotify_watch_t), + offsetof(inotify_watch_t, inw_byvp)); + + list_create(&state->ins_orphans, sizeof (inotify_watch_t), + offsetof(inotify_watch_t, inw_orphan)); + + state->ins_maxwatches = inotify_maxwatches; + state->ins_maxevents = inotify_maxevents; + + mutex_exit(&inotify_lock); + + mutex_enter(&cpu_lock); + + hdlr.cyh_func = inotify_clean; + hdlr.cyh_level = CY_LOW_LEVEL; + hdlr.cyh_arg = state; + + when.cyt_when = 0; + when.cyt_interval = NANOSEC; + + state->ins_cleaner = cyclic_add(&hdlr, &when); + mutex_exit(&cpu_lock); + + return (0); +} + +/*ARGSUSED*/ +static int +inotify_read(dev_t dev, uio_t *uio, cred_t *cr) +{ + inotify_state_t *state; + inotify_kevent_t *event; + minor_t minor = getminor(dev); + int err = 0, nevents = 0; + size_t len; + + state = ddi_get_soft_state(inotify_softstate, minor); + + mutex_enter(&state->ins_lock); + + while (state->ins_head == NULL) { + if (uio->uio_fmode & (FNDELAY|FNONBLOCK)) { + mutex_exit(&state->ins_lock); + return (EAGAIN); + } + + if (!cv_wait_sig_swap(&state->ins_cv, &state->ins_lock)) { + mutex_exit(&state->ins_lock); + return (EINTR); + } + } + + /* + * We have events and we have our lock; return as many as we can. + */ + while ((event = state->ins_head) != NULL) { + len = sizeof (event->ine_event) + event->ine_event.len; + + if (uio->uio_resid < len) { + if (nevents == 0) + err = EINVAL; + break; + } + + nevents++; + + if ((err = uiomove(&event->ine_event, len, UIO_READ, uio)) != 0) + break; + + VERIFY(state->ins_nevents > 0); + state->ins_nevents--; + + VERIFY(state->ins_size > 0); + state->ins_size -= len; + + if ((state->ins_head = event->ine_next) == NULL) { + VERIFY(event == state->ins_tail); + VERIFY(state->ins_nevents == 0); + state->ins_tail = NULL; + } + + kmem_free(event, INOTIFY_EVENT_LENGTH(event)); + } + + mutex_exit(&state->ins_lock); + + return (err); +} + +/*ARGSUSED*/ +static int +inotify_poll(dev_t dev, short events, int anyyet, short *reventsp, + struct pollhead **phpp) +{ + inotify_state_t *state; + minor_t minor = getminor(dev); + + state = ddi_get_soft_state(inotify_softstate, minor); + + mutex_enter(&state->ins_lock); + + if (state->ins_head != NULL) { + *reventsp = events & (POLLRDNORM | POLLIN); + } else { + *reventsp = 0; + + if (!anyyet) + *phpp = &state->ins_pollhd; + } + + mutex_exit(&state->ins_lock); + + return (0); +} + +/*ARGSUSED*/ +static int +inotify_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv) +{ + inotify_state_t *state; + minor_t minor = getminor(dev); + file_t *fp; + int rval; + + state = ddi_get_soft_state(inotify_softstate, minor); + + switch (cmd) { + case INOTIFYIOC_ADD_WATCH: { + inotify_addwatch_t addwatch; + file_t *fp; + + if (copyin((void *)arg, &addwatch, sizeof (addwatch)) != 0) + return (EFAULT); + + if ((fp = getf(addwatch.inaw_fd)) == NULL) + return (EBADF); + + rval = inotify_add_watch(state, fp->f_vnode, + addwatch.inaw_mask, rv); + + releasef(addwatch.inaw_fd); + return (rval); + } + + case INOTIFYIOC_ADD_CHILD: { + inotify_addchild_t addchild; + char name[MAXPATHLEN]; + + if (copyin((void *)arg, &addchild, sizeof (addchild)) != 0) + return (EFAULT); + + if (copyinstr(addchild.inac_name, name, MAXPATHLEN, NULL) != 0) + return (EFAULT); + + if ((fp = getf(addchild.inac_fd)) == NULL) + return (EBADF); + + rval = inotify_add_child(state, fp->f_vnode, name); + + releasef(addchild.inac_fd); + return (rval); + } + + case INOTIFYIOC_RM_WATCH: + return (inotify_rm_watch(state, arg)); + + case INOTIFYIOC_ACTIVATE: + return (inotify_activate(state, arg)); + + case FIONREAD: { + int32_t size; + + mutex_enter(&state->ins_lock); + size = state->ins_size; + mutex_exit(&state->ins_lock); + + if (copyout(&size, (void *)arg, sizeof (size)) != 0) + return (EFAULT); + + return (0); + } + + default: + break; + } + + return (ENOTTY); +} + +/*ARGSUSED*/ +static int +inotify_close(dev_t dev, int flag, int otyp, cred_t *cred_p) +{ + inotify_state_t *state, **sp; + inotify_watch_t *watch, *zombies; + inotify_kevent_t *event; + minor_t minor = getminor(dev); + + state = ddi_get_soft_state(inotify_softstate, minor); + + if (state->ins_pollhd.ph_list != NULL) { + pollwakeup(&state->ins_pollhd, POLLERR); + pollhead_clean(&state->ins_pollhd); + } + + mutex_enter(&state->ins_lock); + + /* + * First, destroy all of our watches. + */ + while ((watch = avl_first(&state->ins_bywd)) != NULL) + inotify_watch_remove(state, watch); + + /* + * And now destroy our event queue. + */ + while ((event = state->ins_head) != NULL) { + state->ins_head = event->ine_next; + kmem_free(event, INOTIFY_EVENT_LENGTH(event)); + } + + zombies = state->ins_zombies; + state->ins_zombies = NULL; + mutex_exit(&state->ins_lock); + + /* + * Now that our state lock is dropped, we can synchronously wait on + * any zombies. + */ + while ((watch = zombies) != NULL) { + zombies = zombies->inw_parent; + + mutex_enter(&watch->inw_lock); + + while (watch->inw_refcnt > 1) + cv_wait(&watch->inw_cv, &watch->inw_lock); + + inotify_watch_destroy(watch); + } + + mutex_enter(&cpu_lock); + cyclic_remove(state->ins_cleaner); + mutex_exit(&cpu_lock); + + mutex_enter(&inotify_lock); + + /* + * Remove our state from our global list, and release our hold on + * the cred. + */ + for (sp = &inotify_state; *sp != state; sp = &((*sp)->ins_next)) + VERIFY(*sp != NULL); + + *sp = (*sp)->ins_next; + crfree(state->ins_cred); + + ddi_soft_state_free(inotify_softstate, minor); + vmem_free(inotify_minor, (void *)(uintptr_t)minor, 1); + + mutex_exit(&inotify_lock); + + return (0); +} + +/*ARGSUSED*/ +static int +inotify_attach(dev_info_t *devi, ddi_attach_cmd_t cmd) +{ + mutex_enter(&inotify_lock); + + if (ddi_soft_state_init(&inotify_softstate, + sizeof (inotify_state_t), 0) != 0) { + cmn_err(CE_NOTE, "/dev/inotify failed to create soft state"); + mutex_exit(&inotify_lock); + return (DDI_FAILURE); + } + + if (ddi_create_minor_node(devi, "inotify", S_IFCHR, + INOTIFYMNRN_INOTIFY, DDI_PSEUDO, NULL) == DDI_FAILURE) { + cmn_err(CE_NOTE, "/dev/inotify couldn't create minor node"); + ddi_soft_state_fini(&inotify_softstate); + mutex_exit(&inotify_lock); + return (DDI_FAILURE); + } + + if (fem_create("inotify_fem", + inotify_vnodesrc_template, &inotify_femp) != 0) { + cmn_err(CE_NOTE, "/dev/inotify couldn't create FEM state"); + ddi_remove_minor_node(devi, NULL); + ddi_soft_state_fini(&inotify_softstate); + mutex_exit(&inotify_lock); + return (DDI_FAILURE); + } + + ddi_report_dev(devi); + inotify_devi = devi; + + inotify_minor = vmem_create("inotify_minor", (void *)INOTIFYMNRN_CLONE, + UINT32_MAX - INOTIFYMNRN_CLONE, 1, NULL, NULL, NULL, 0, + VM_SLEEP | VMC_IDENTIFIER); + + mutex_exit(&inotify_lock); + + return (DDI_SUCCESS); +} + +/*ARGSUSED*/ +static int +inotify_detach(dev_info_t *dip, ddi_detach_cmd_t cmd) +{ + switch (cmd) { + case DDI_DETACH: + break; + + case DDI_SUSPEND: + return (DDI_SUCCESS); + + default: + return (DDI_FAILURE); + } + + mutex_enter(&inotify_lock); + fem_free(inotify_femp); + vmem_destroy(inotify_minor); + + ddi_remove_minor_node(inotify_devi, NULL); + inotify_devi = NULL; + + ddi_soft_state_fini(&inotify_softstate); + mutex_exit(&inotify_lock); + + return (DDI_SUCCESS); +} + +/*ARGSUSED*/ +static int +inotify_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result) +{ + int error; + + switch (infocmd) { + case DDI_INFO_DEVT2DEVINFO: + *result = (void *)inotify_devi; + error = DDI_SUCCESS; + break; + case DDI_INFO_DEVT2INSTANCE: + *result = (void *)0; + error = DDI_SUCCESS; + break; + default: + error = DDI_FAILURE; + } + return (error); +} + +static struct cb_ops inotify_cb_ops = { + inotify_open, /* open */ + inotify_close, /* close */ + nulldev, /* strategy */ + nulldev, /* print */ + nodev, /* dump */ + inotify_read, /* read */ + nodev, /* write */ + inotify_ioctl, /* ioctl */ + nodev, /* devmap */ + nodev, /* mmap */ + nodev, /* segmap */ + inotify_poll, /* poll */ + ddi_prop_op, /* cb_prop_op */ + 0, /* streamtab */ + D_NEW | D_MP /* Driver compatibility flag */ +}; + +static struct dev_ops inotify_ops = { + DEVO_REV, /* devo_rev */ + 0, /* refcnt */ + inotify_info, /* get_dev_info */ + nulldev, /* identify */ + nulldev, /* probe */ + inotify_attach, /* attach */ + inotify_detach, /* detach */ + nodev, /* reset */ + &inotify_cb_ops, /* driver operations */ + NULL, /* bus operations */ + nodev, /* dev power */ + ddi_quiesce_not_needed, /* quiesce */ +}; + +static struct modldrv modldrv = { + &mod_driverops, /* module type (this is a pseudo driver) */ + "inotify support", /* name of module */ + &inotify_ops, /* driver ops */ +}; + +static struct modlinkage modlinkage = { + MODREV_1, + (void *)&modldrv, + NULL +}; + +int +_init(void) +{ + return (mod_install(&modlinkage)); +} + +int +_info(struct modinfo *modinfop) +{ + return (mod_info(&modlinkage, modinfop)); +} + +int +_fini(void) +{ + return (mod_remove(&modlinkage)); +} |