/* $NetBSD: kern_descrip.c,v 1.184 2008/11/18 13:01:41 pooka Exp $ */ /*- * Copyright (c) 2008 The NetBSD Foundation, Inc. * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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. */ /* * Copyright (c) 1982, 1986, 1989, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * 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. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * @(#)kern_descrip.c 8.8 (Berkeley) 2/14/95 */ /* * File descriptor management. */ #include __KERNEL_RCSID(0, "$NetBSD: kern_descrip.c,v 1.184 2008/11/18 13:01:41 pooka Exp $"); #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 file_ctor(void *, void *, int); static void file_dtor(void *, void *); static int fdfile_ctor(void *, void *, int); static void fdfile_dtor(void *, void *); static int filedesc_ctor(void *, void *, int); static void filedesc_dtor(void *, void *); static int filedescopen(dev_t, int, int, lwp_t *); kmutex_t filelist_lock; /* lock on filehead */ struct filelist filehead; /* head of list of open files */ u_int nfiles; /* actual number of open files */ static pool_cache_t filedesc_cache; static pool_cache_t file_cache; static pool_cache_t fdfile_cache; MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table"); const struct cdevsw filedesc_cdevsw = { filedescopen, noclose, noread, nowrite, noioctl, nostop, notty, nopoll, nommap, nokqfilter, D_OTHER | D_MPSAFE, }; /* For ease of reading. */ __strong_alias(fd_putvnode,fd_putfile) __strong_alias(fd_putsock,fd_putfile) /* * Initialize the descriptor system. */ void fd_sys_init(void) { mutex_init(&filelist_lock, MUTEX_DEFAULT, IPL_NONE); file_cache = pool_cache_init(sizeof(file_t), coherency_unit, 0, 0, "file", NULL, IPL_NONE, file_ctor, file_dtor, NULL); KASSERT(file_cache != NULL); fdfile_cache = pool_cache_init(sizeof(fdfile_t), coherency_unit, 0, PR_LARGECACHE, "fdfile", NULL, IPL_NONE, fdfile_ctor, fdfile_dtor, NULL); KASSERT(fdfile_cache != NULL); filedesc_cache = pool_cache_init(sizeof(filedesc_t), coherency_unit, 0, 0, "filedesc", NULL, IPL_NONE, filedesc_ctor, filedesc_dtor, NULL); KASSERT(filedesc_cache != NULL); } static int fd_next_zero(filedesc_t *fdp, uint32_t *bitmap, int want, u_int bits) { int i, off, maxoff; uint32_t sub; KASSERT(mutex_owned(&fdp->fd_lock)); if (want > bits) return -1; off = want >> NDENTRYSHIFT; i = want & NDENTRYMASK; if (i) { sub = bitmap[off] | ((u_int)~0 >> (NDENTRIES - i)); if (sub != ~0) goto found; off++; } maxoff = NDLOSLOTS(bits); while (off < maxoff) { if ((sub = bitmap[off]) != ~0) goto found; off++; } return (-1); found: return (off << NDENTRYSHIFT) + ffs(~sub) - 1; } static int fd_last_set(filedesc_t *fd, int last) { int off, i; fdfile_t **ofiles = fd->fd_ofiles; uint32_t *bitmap = fd->fd_lomap; KASSERT(mutex_owned(&fd->fd_lock)); off = (last - 1) >> NDENTRYSHIFT; while (off >= 0 && !bitmap[off]) off--; if (off < 0) return (-1); i = ((off + 1) << NDENTRYSHIFT) - 1; if (i >= last) i = last - 1; /* XXX should use bitmap */ /* XXXAD does not work for fd_copy() */ while (i > 0 && (ofiles[i] == NULL || !ofiles[i]->ff_allocated)) i--; return (i); } void fd_used(filedesc_t *fdp, unsigned fd) { u_int off = fd >> NDENTRYSHIFT; fdfile_t *ff; ff = fdp->fd_ofiles[fd]; KASSERT(mutex_owned(&fdp->fd_lock)); KASSERT((fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) == 0); KASSERT(ff != NULL); KASSERT(ff->ff_file == NULL); KASSERT(!ff->ff_allocated); ff->ff_allocated = 1; fdp->fd_lomap[off] |= 1 << (fd & NDENTRYMASK); if (fdp->fd_lomap[off] == ~0) { KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] & (1 << (off & NDENTRYMASK))) == 0); fdp->fd_himap[off >> NDENTRYSHIFT] |= 1 << (off & NDENTRYMASK); } if ((int)fd > fdp->fd_lastfile) { fdp->fd_lastfile = fd; } if (fd >= NDFDFILE) { fdp->fd_nused++; } else { KASSERT(ff == (fdfile_t *)fdp->fd_dfdfile[fd]); } } void fd_unused(filedesc_t *fdp, unsigned fd) { u_int off = fd >> NDENTRYSHIFT; fdfile_t *ff; ff = fdp->fd_ofiles[fd]; /* * Don't assert the lock is held here, as we may be copying * the table during exec() and it is not needed there. * procfs and sysctl are locked out by proc::p_reflock. * * KASSERT(mutex_owned(&fdp->fd_lock)); */ KASSERT(ff != NULL); KASSERT(ff->ff_file == NULL); KASSERT(ff->ff_allocated); if (fd < fdp->fd_freefile) { fdp->fd_freefile = fd; } if (fdp->fd_lomap[off] == ~0) { KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] & (1 << (off & NDENTRYMASK))) != 0); fdp->fd_himap[off >> NDENTRYSHIFT] &= ~(1 << (off & NDENTRYMASK)); } KASSERT((fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) != 0); fdp->fd_lomap[off] &= ~(1 << (fd & NDENTRYMASK)); ff->ff_allocated = 0; KASSERT(fd <= fdp->fd_lastfile); if (fd == fdp->fd_lastfile) { fdp->fd_lastfile = fd_last_set(fdp, fd); } if (fd >= NDFDFILE) { KASSERT(fdp->fd_nused > 0); fdp->fd_nused--; } else { KASSERT(ff == (fdfile_t *)fdp->fd_dfdfile[fd]); } } /* * Custom version of fd_unused() for fd_copy(), where the descriptor * table is not yet fully initialized. */ static inline void fd_zap(filedesc_t *fdp, unsigned fd) { u_int off = fd >> NDENTRYSHIFT; if (fd < fdp->fd_freefile) { fdp->fd_freefile = fd; } if (fdp->fd_lomap[off] == ~0) { KASSERT((fdp->fd_himap[off >> NDENTRYSHIFT] & (1 << (off & NDENTRYMASK))) != 0); fdp->fd_himap[off >> NDENTRYSHIFT] &= ~(1 << (off & NDENTRYMASK)); } KASSERT((fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) != 0); fdp->fd_lomap[off] &= ~(1 << (fd & NDENTRYMASK)); } bool fd_isused(filedesc_t *fdp, unsigned fd) { u_int off = fd >> NDENTRYSHIFT; KASSERT(fd < fdp->fd_nfiles); return (fdp->fd_lomap[off] & (1 << (fd & NDENTRYMASK))) != 0; } /* * Look up the file structure corresponding to a file descriptor * and return the file, holding a reference on the descriptor. */ inline file_t * fd_getfile(unsigned fd) { filedesc_t *fdp; fdfile_t *ff; file_t *fp; fdp = curlwp->l_fd; /* * Look up the fdfile structure representing this descriptor. * Ensure that we see fd_nfiles before fd_ofiles since we * are doing this unlocked. See fd_tryexpand(). */ if (__predict_false(fd >= fdp->fd_nfiles)) { return NULL; } membar_consumer(); ff = fdp->fd_ofiles[fd]; KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); if (__predict_false(ff == NULL)) { return NULL; } /* * Now get a reference to the descriptor. Issue a memory * barrier to ensure that we acquire the file pointer _after_ * adding a reference. If no memory barrier, we could fetch * a stale pointer. */ atomic_inc_uint(&ff->ff_refcnt); #ifndef __HAVE_ATOMIC_AS_MEMBAR membar_enter(); #endif /* * If the file is not open or is being closed then put the * reference back. */ fp = ff->ff_file; if (__predict_true(fp != NULL)) { return fp; } fd_putfile(fd); return NULL; } /* * Release a reference to a file descriptor acquired with fd_getfile(). */ void fd_putfile(unsigned fd) { filedesc_t *fdp; fdfile_t *ff; u_int u, v; fdp = curlwp->l_fd; ff = fdp->fd_ofiles[fd]; KASSERT(fd < fdp->fd_nfiles); KASSERT(ff != NULL); KASSERT((ff->ff_refcnt & FR_MASK) > 0); KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); /* * Ensure that any use of the file is complete and globally * visible before dropping the final reference. If no membar, * the current CPU could still access memory associated with * the file after it has been freed or recycled by another * CPU. */ #ifndef __HAVE_ATOMIC_AS_MEMBAR membar_exit(); #endif /* * Be optimistic and start out with the assumption that no other * threads are trying to close the descriptor. If the CAS fails, * we lost a race and/or it's being closed. */ for (u = ff->ff_refcnt & FR_MASK;; u = v) { v = atomic_cas_uint(&ff->ff_refcnt, u, u - 1); if (__predict_true(u == v)) { return; } if (__predict_false((v & FR_CLOSING) != 0)) { break; } } /* Another thread is waiting to close the file: join it. */ (void)fd_close(fd); } /* * Convenience wrapper around fd_getfile() that returns reference * to a vnode. */ int fd_getvnode(unsigned fd, file_t **fpp) { vnode_t *vp; file_t *fp; fp = fd_getfile(fd); if (__predict_false(fp == NULL)) { return EBADF; } if (__predict_false(fp->f_type != DTYPE_VNODE)) { fd_putfile(fd); return EINVAL; } vp = fp->f_data; if (__predict_false(vp->v_type == VBAD)) { /* XXX Is this case really necessary? */ fd_putfile(fd); return EBADF; } *fpp = fp; return 0; } /* * Convenience wrapper around fd_getfile() that returns reference * to a socket. */ int fd_getsock(unsigned fd, struct socket **sop) { file_t *fp; fp = fd_getfile(fd); if (__predict_false(fp == NULL)) { return EBADF; } if (__predict_false(fp->f_type != DTYPE_SOCKET)) { fd_putfile(fd); return ENOTSOCK; } *sop = fp->f_data; return 0; } /* * Look up the file structure corresponding to a file descriptor * and return it with a reference held on the file, not the * descriptor. * * This is heavyweight and only used when accessing descriptors * from a foreign process. The caller must ensure that `p' does * not exit or fork across this call. * * To release the file (not descriptor) reference, use closef(). */ file_t * fd_getfile2(proc_t *p, unsigned fd) { filedesc_t *fdp; fdfile_t *ff; file_t *fp; fdp = p->p_fd; mutex_enter(&fdp->fd_lock); if (fd > fdp->fd_nfiles) { mutex_exit(&fdp->fd_lock); return NULL; } if ((ff = fdp->fd_ofiles[fd]) == NULL) { mutex_exit(&fdp->fd_lock); return NULL; } mutex_enter(&ff->ff_lock); if ((fp = ff->ff_file) == NULL) { mutex_exit(&ff->ff_lock); mutex_exit(&fdp->fd_lock); return NULL; } mutex_enter(&fp->f_lock); fp->f_count++; mutex_exit(&fp->f_lock); mutex_exit(&ff->ff_lock); mutex_exit(&fdp->fd_lock); return fp; } /* * Internal form of close. Must be called with a reference to the * descriptor, and will drop the reference. When all descriptor * references are dropped, releases the descriptor slot and a single * reference to the file structure. */ int fd_close(unsigned fd) { struct flock lf; filedesc_t *fdp; fdfile_t *ff; file_t *fp; proc_t *p; lwp_t *l; l = curlwp; p = l->l_proc; fdp = l->l_fd; ff = fdp->fd_ofiles[fd]; KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); mutex_enter(&ff->ff_lock); KASSERT((ff->ff_refcnt & FR_MASK) > 0); if (ff->ff_file == NULL) { /* * Another user of the file is already closing, and is * waiting for other users of the file to drain. Release * our reference, and wake up the closer. */ atomic_dec_uint(&ff->ff_refcnt); cv_broadcast(&ff->ff_closing); mutex_exit(&ff->ff_lock); /* * An application error, so pretend that the descriptor * was already closed. We can't safely wait for it to * be closed without potentially deadlocking. */ return (EBADF); } KASSERT((ff->ff_refcnt & FR_CLOSING) == 0); /* * There may be multiple users of this file within the process. * Notify existing and new users that the file is closing. This * will prevent them from adding additional uses to this file * while we are closing it. */ fp = ff->ff_file; ff->ff_file = NULL; ff->ff_exclose = false; /* * We expect the caller to hold a descriptor reference - drop it. * The reference count may increase beyond zero at this point due * to an erroneous descriptor reference by an application, but * fd_getfile() will notice that the file is being closed and drop * the reference again. */ #ifndef __HAVE_ATOMIC_AS_MEMBAR membar_producer(); #endif if (__predict_false(atomic_dec_uint_nv(&ff->ff_refcnt) != 0)) { /* * Wait for other references to drain. This is typically * an application error - the descriptor is being closed * while still in use. * */ atomic_or_uint(&ff->ff_refcnt, FR_CLOSING); /* * Remove any knotes attached to the file. A knote * attached to the descriptor can hold references on it. */ if (!SLIST_EMPTY(&ff->ff_knlist)) { mutex_exit(&ff->ff_lock); knote_fdclose(fd); mutex_enter(&ff->ff_lock); } /* * We need to see the count drop to zero at least once, * in order to ensure that all pre-existing references * have been drained. New references past this point are * of no interest. */ while ((ff->ff_refcnt & FR_MASK) != 0) { cv_wait(&ff->ff_closing, &ff->ff_lock); } atomic_and_uint(&ff->ff_refcnt, ~FR_CLOSING); } else { /* If no references, there must be no knotes. */ KASSERT(SLIST_EMPTY(&ff->ff_knlist)); } mutex_exit(&ff->ff_lock); /* * POSIX record locking dictates that any close releases ALL * locks owned by this process. This is handled by setting * a flag in the unlock to free ONLY locks obeying POSIX * semantics, and not to free BSD-style file locks. * If the descriptor was in a message, POSIX-style locks * aren't passed with the descriptor. */ if ((p->p_flag & PK_ADVLOCK) != 0 && fp->f_type == DTYPE_VNODE) { lf.l_whence = SEEK_SET; lf.l_start = 0; lf.l_len = 0; lf.l_type = F_UNLCK; (void)VOP_ADVLOCK(fp->f_data, p, F_UNLCK, &lf, F_POSIX); } /* Free descriptor slot. */ mutex_enter(&fdp->fd_lock); fd_unused(fdp, fd); mutex_exit(&fdp->fd_lock); /* Now drop reference to the file itself. */ return closef(fp); } /* * Duplicate a file descriptor. */ int fd_dup(file_t *fp, int minfd, int *newp, bool exclose) { proc_t *p; int error; p = curproc; while ((error = fd_alloc(p, minfd, newp)) != 0) { if (error != ENOSPC) { return error; } fd_tryexpand(p); } curlwp->l_fd->fd_ofiles[*newp]->ff_exclose = exclose; fd_affix(p, fp, *newp); return 0; } /* * dup2 operation. */ int fd_dup2(file_t *fp, unsigned new) { filedesc_t *fdp; fdfile_t *ff; fdp = curlwp->l_fd; /* * Ensure there are enough slots in the descriptor table, * and allocate an fdfile_t up front in case we need it. */ while (new >= fdp->fd_nfiles) { fd_tryexpand(curproc); } ff = pool_cache_get(fdfile_cache, PR_WAITOK); /* * If there is already a file open, close it. If the file is * half open, wait for it to be constructed before closing it. * XXX Potential for deadlock here? */ mutex_enter(&fdp->fd_lock); while (fd_isused(fdp, new)) { mutex_exit(&fdp->fd_lock); if (fd_getfile(new) != NULL) { (void)fd_close(new); } else { /* XXX Crummy, but unlikely to happen. */ kpause("dup2", false, 1, NULL); } mutex_enter(&fdp->fd_lock); } if (fdp->fd_ofiles[new] == NULL) { KASSERT(new >= NDFDFILE); fdp->fd_ofiles[new] = ff; ff = NULL; } fd_used(fdp, new); mutex_exit(&fdp->fd_lock); /* Slot is now allocated. Insert copy of the file. */ fd_affix(curproc, fp, new); if (ff != NULL) { pool_cache_put(fdfile_cache, ff); } return 0; } /* * Drop reference to a file structure. */ int closef(file_t *fp) { struct flock lf; int error; /* * Drop reference. If referenced elsewhere it's still open * and we have nothing more to do. */ mutex_enter(&fp->f_lock); KASSERT(fp->f_count > 0); if (--fp->f_count > 0) { mutex_exit(&fp->f_lock); return 0; } KASSERT(fp->f_count == 0); mutex_exit(&fp->f_lock); /* We held the last reference - release locks, close and free. */ if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) { lf.l_whence = SEEK_SET; lf.l_start = 0; lf.l_len = 0; lf.l_type = F_UNLCK; (void)VOP_ADVLOCK(fp->f_data, fp, F_UNLCK, &lf, F_FLOCK); } if (fp->f_ops != NULL) { error = (*fp->f_ops->fo_close)(fp); } else { error = 0; } ffree(fp); return error; } /* * Allocate a file descriptor for the process. */ int fd_alloc(proc_t *p, int want, int *result) { filedesc_t *fdp; int i, lim, last, error; u_int off, new; fdfile_t *ff; KASSERT(p == curproc || p == &proc0); fdp = p->p_fd; ff = pool_cache_get(fdfile_cache, PR_WAITOK); KASSERT(ff->ff_refcnt == 0); KASSERT(ff->ff_file == NULL); /* * Search for a free descriptor starting at the higher * of want or fd_freefile. */ mutex_enter(&fdp->fd_lock); KASSERT(fdp->fd_ofiles[0] == (fdfile_t *)fdp->fd_dfdfile[0]); lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles); last = min(fdp->fd_nfiles, lim); for (;;) { if ((i = want) < fdp->fd_freefile) i = fdp->fd_freefile; off = i >> NDENTRYSHIFT; new = fd_next_zero(fdp, fdp->fd_himap, off, (last + NDENTRIES - 1) >> NDENTRYSHIFT); if (new == -1) break; i = fd_next_zero(fdp, &fdp->fd_lomap[new], new > off ? 0 : i & NDENTRYMASK, NDENTRIES); if (i == -1) { /* * Free file descriptor in this block was * below want, try again with higher want. */ want = (new + 1) << NDENTRYSHIFT; continue; } i += (new << NDENTRYSHIFT); if (i >= last) { break; } if (fdp->fd_ofiles[i] == NULL) { KASSERT(i >= NDFDFILE); fdp->fd_ofiles[i] = ff; } else { pool_cache_put(fdfile_cache, ff); } KASSERT(fdp->fd_ofiles[i]->ff_file == NULL); fd_used(fdp, i); if (want <= fdp->fd_freefile) { fdp->fd_freefile = i; } *result = i; mutex_exit(&fdp->fd_lock); KASSERT(i >= NDFDFILE || fdp->fd_ofiles[i] == (fdfile_t *)fdp->fd_dfdfile[i]); return 0; } /* No space in current array. Let the caller expand and retry. */ error = (fdp->fd_nfiles >= lim) ? EMFILE : ENOSPC; mutex_exit(&fdp->fd_lock); pool_cache_put(fdfile_cache, ff); return error; } /* * Expand a process' descriptor table. */ void fd_tryexpand(proc_t *p) { filedesc_t *fdp; int i, numfiles, oldnfiles; fdfile_t **newofile; uint32_t *newhimap, *newlomap; KASSERT(p == curproc || p == &proc0); fdp = p->p_fd; newhimap = NULL; newlomap = NULL; oldnfiles = fdp->fd_nfiles; if (oldnfiles < NDEXTENT) numfiles = NDEXTENT; else numfiles = 2 * oldnfiles; newofile = malloc(numfiles * sizeof(fdfile_t *), M_FILEDESC, M_WAITOK); if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { newhimap = malloc(NDHISLOTS(numfiles) * sizeof(uint32_t), M_FILEDESC, M_WAITOK); newlomap = malloc(NDLOSLOTS(numfiles) * sizeof(uint32_t), M_FILEDESC, M_WAITOK); } mutex_enter(&fdp->fd_lock); KASSERT(fdp->fd_ofiles[0] == (fdfile_t *)fdp->fd_dfdfile[0]); if (fdp->fd_nfiles != oldnfiles) { /* fdp changed; caller must retry */ mutex_exit(&fdp->fd_lock); free(newofile, M_FILEDESC); if (newhimap != NULL) free(newhimap, M_FILEDESC); if (newlomap != NULL) free(newlomap, M_FILEDESC); return; } /* Copy the existing ofile array and zero the new portion. */ i = sizeof(fdfile_t *) * fdp->fd_nfiles; memcpy(newofile, fdp->fd_ofiles, i); memset((uint8_t *)newofile + i, 0, numfiles * sizeof(fdfile_t *) - i); /* * Link old ofiles array into list to be discarded. We defer * freeing until process exit if the descriptor table is visble * to other threads. */ if (oldnfiles > NDFILE) { if ((fdp->fd_refcnt | p->p_nlwps) > 1) { *(void **)fdp->fd_ofiles = fdp->fd_discard; fdp->fd_discard = fdp->fd_ofiles; } else { free(fdp->fd_ofiles, M_FILEDESC); } } if (NDHISLOTS(numfiles) > NDHISLOTS(oldnfiles)) { i = NDHISLOTS(oldnfiles) * sizeof(uint32_t); memcpy(newhimap, fdp->fd_himap, i); memset((uint8_t *)newhimap + i, 0, NDHISLOTS(numfiles) * sizeof(uint32_t) - i); i = NDLOSLOTS(oldnfiles) * sizeof(uint32_t); memcpy(newlomap, fdp->fd_lomap, i); memset((uint8_t *)newlomap + i, 0, NDLOSLOTS(numfiles) * sizeof(uint32_t) - i); if (NDHISLOTS(oldnfiles) > NDHISLOTS(NDFILE)) { free(fdp->fd_himap, M_FILEDESC); free(fdp->fd_lomap, M_FILEDESC); } fdp->fd_himap = newhimap; fdp->fd_lomap = newlomap; } /* * All other modifications must become globally visible before * the change to fd_nfiles. See fd_getfile(). */ fdp->fd_ofiles = newofile; membar_producer(); fdp->fd_nfiles = numfiles; mutex_exit(&fdp->fd_lock); KASSERT(fdp->fd_ofiles[0] == (fdfile_t *)fdp->fd_dfdfile[0]); } /* * Create a new open file structure and allocate a file descriptor * for the current process. */ int fd_allocfile(file_t **resultfp, int *resultfd) { file_t *fp; proc_t *p; int error; p = curproc; while ((error = fd_alloc(p, 0, resultfd)) != 0) { if (error != ENOSPC) { return error; } fd_tryexpand(p); } fp = pool_cache_get(file_cache, PR_WAITOK); KASSERT(fp->f_count == 0); fp->f_cred = kauth_cred_get(); kauth_cred_hold(fp->f_cred); if (__predict_false(atomic_inc_uint_nv(&nfiles) >= maxfiles)) { fd_abort(p, fp, *resultfd); tablefull("file", "increase kern.maxfiles or MAXFILES"); return ENFILE; } fp->f_advice = 0; fp->f_msgcount = 0; fp->f_offset = 0; fp->f_iflags = 0; *resultfp = fp; return 0; } /* * Successful creation of a new descriptor: make visible to the process. */ void fd_affix(proc_t *p, file_t *fp, unsigned fd) { fdfile_t *ff; filedesc_t *fdp; KASSERT(p == curproc || p == &proc0); /* Add a reference to the file structure. */ mutex_enter(&fp->f_lock); fp->f_count++; mutex_exit(&fp->f_lock); /* * Insert the new file into the descriptor slot. * * The memory barriers provided by lock activity in this routine * ensure that any updates to the file structure become globally * visible before the file becomes visible to other LWPs in the * current process. */ fdp = p->p_fd; ff = fdp->fd_ofiles[fd]; KASSERT(ff != NULL); KASSERT(ff->ff_file == NULL); KASSERT(ff->ff_allocated); KASSERT(fd_isused(fdp, fd)); KASSERT(fd >= NDFDFILE || fdp->fd_ofiles[fd] == (fdfile_t *)fdp->fd_dfdfile[fd]); /* No need to lock in order to make file initially visible. */ ff->ff_file = fp; } /* * Abort creation of a new descriptor: free descriptor slot and file. */ void fd_abort(proc_t *p, file_t *fp, unsigned fd) { filedesc_t *fdp; fdfile_t *ff; KASSERT(p == curproc || p == &proc0); fdp = p->p_fd; ff = fdp->fd_ofiles[fd]; KASSERT(fd >= NDFDFILE || fdp->fd_ofiles[fd] == (fdfile_t *)fdp->fd_dfdfile[fd]); mutex_enter(&fdp->fd_lock); KASSERT(fd_isused(fdp, fd)); fd_unused(fdp, fd); mutex_exit(&fdp->fd_lock); if (fp != NULL) { ffree(fp); } } /* * Free a file descriptor. */ void ffree(file_t *fp) { KASSERT(fp->f_count == 0); atomic_dec_uint(&nfiles); kauth_cred_free(fp->f_cred); pool_cache_put(file_cache, fp); } static int file_ctor(void *arg, void *obj, int flags) { file_t *fp = obj; memset(fp, 0, sizeof(*fp)); mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE); mutex_enter(&filelist_lock); LIST_INSERT_HEAD(&filehead, fp, f_list); mutex_exit(&filelist_lock); return 0; } static void file_dtor(void *arg, void *obj) { file_t *fp = obj; mutex_enter(&filelist_lock); LIST_REMOVE(fp, f_list); mutex_exit(&filelist_lock); mutex_destroy(&fp->f_lock); } static int fdfile_ctor(void *arg, void *obj, int flags) { fdfile_t *ff = obj; memset(ff, 0, sizeof(*ff)); mutex_init(&ff->ff_lock, MUTEX_DEFAULT, IPL_NONE); cv_init(&ff->ff_closing, "fdclose"); return 0; } static void fdfile_dtor(void *arg, void *obj) { fdfile_t *ff = obj; mutex_destroy(&ff->ff_lock); cv_destroy(&ff->ff_closing); } file_t * fgetdummy(void) { file_t *fp; fp = kmem_alloc(sizeof(*fp), KM_SLEEP); if (fp != NULL) { memset(fp, 0, sizeof(*fp)); mutex_init(&fp->f_lock, MUTEX_DEFAULT, IPL_NONE); } return fp; } void fputdummy(file_t *fp) { mutex_destroy(&fp->f_lock); kmem_free(fp, sizeof(*fp)); } /* * Create an initial filedesc structure. */ filedesc_t * fd_init(filedesc_t *fdp) { unsigned fd; if (fdp == NULL) { fdp = pool_cache_get(filedesc_cache, PR_WAITOK); } else { filedesc_ctor(NULL, fdp, PR_WAITOK); } fdp->fd_refcnt = 1; fdp->fd_ofiles = fdp->fd_dfiles; fdp->fd_nfiles = NDFILE; fdp->fd_himap = fdp->fd_dhimap; fdp->fd_lomap = fdp->fd_dlomap; KASSERT(fdp->fd_lastfile == -1); KASSERT(fdp->fd_lastkqfile == -1); KASSERT(fdp->fd_knhash == NULL); memset(&fdp->fd_startzero, 0, sizeof(*fdp) - offsetof(filedesc_t, fd_startzero)); for (fd = 0; fd < NDFDFILE; fd++) { fdp->fd_ofiles[fd] = (fdfile_t *)fdp->fd_dfdfile[fd]; } return fdp; } /* * Initialize a file descriptor table. */ static int filedesc_ctor(void *arg, void *obj, int flag) { filedesc_t *fdp = obj; int i; memset(fdp, 0, sizeof(*fdp)); mutex_init(&fdp->fd_lock, MUTEX_DEFAULT, IPL_NONE); fdp->fd_lastfile = -1; fdp->fd_lastkqfile = -1; CTASSERT(sizeof(fdp->fd_dfdfile[0]) >= sizeof(fdfile_t)); for (i = 0; i < NDFDFILE; i++) { fdfile_ctor(NULL, fdp->fd_dfdfile[i], PR_WAITOK); } return 0; } static void filedesc_dtor(void *arg, void *obj) { filedesc_t *fdp = obj; int i; for (i = 0; i < NDFDFILE; i++) { fdfile_dtor(NULL, fdp->fd_dfdfile[i]); } mutex_destroy(&fdp->fd_lock); } /* * Make p2 share p1's filedesc structure. */ void fd_share(struct proc *p2) { filedesc_t *fdp; fdp = curlwp->l_fd; p2->p_fd = fdp; atomic_inc_uint(&fdp->fd_refcnt); } /* * Copy a filedesc structure. */ filedesc_t * fd_copy(void) { filedesc_t *newfdp, *fdp; fdfile_t *ff, *fflist, **ffp, **nffp, *ff2; int i, nused, numfiles, lastfile, j, newlast; file_t *fp; fdp = curproc->p_fd; newfdp = pool_cache_get(filedesc_cache, PR_WAITOK); newfdp->fd_refcnt = 1; KASSERT(newfdp->fd_knhash == NULL); KASSERT(newfdp->fd_knhashmask == 0); KASSERT(newfdp->fd_discard == NULL); for (;;) { numfiles = fdp->fd_nfiles; lastfile = fdp->fd_lastfile; /* * If the number of open files fits in the internal arrays * of the open file structure, use them, otherwise allocate * additional memory for the number of descriptors currently * in use. */ if (lastfile < NDFILE) { i = NDFILE; newfdp->fd_ofiles = newfdp->fd_dfiles; } else { /* * Compute the smallest multiple of NDEXTENT needed * for the file descriptors currently in use, * allowing the table to shrink. */ i = numfiles; while (i >= 2 * NDEXTENT && i > lastfile * 2) { i /= 2; } newfdp->fd_ofiles = malloc(i * sizeof(fdfile_t *), M_FILEDESC, M_WAITOK); KASSERT(i >= NDFILE); } if (NDHISLOTS(i) <= NDHISLOTS(NDFILE)) { newfdp->fd_himap = newfdp->fd_dhimap; newfdp->fd_lomap = newfdp->fd_dlomap; } else { newfdp->fd_himap = malloc(NDHISLOTS(i) * sizeof(uint32_t), M_FILEDESC, M_WAITOK); newfdp->fd_lomap = malloc(NDLOSLOTS(i) * sizeof(uint32_t), M_FILEDESC, M_WAITOK); } /* * Allocate and string together fdfile structures. * We abuse fdfile_t::ff_file here, but it will be * cleared before this routine returns. */ nused = fdp->fd_nused; fflist = NULL; for (j = nused; j != 0; j--) { ff = pool_cache_get(fdfile_cache, PR_WAITOK); ff->ff_file = (void *)fflist; fflist = ff; } mutex_enter(&fdp->fd_lock); if (numfiles == fdp->fd_nfiles && nused == fdp->fd_nused && lastfile == fdp->fd_lastfile) { break; } mutex_exit(&fdp->fd_lock); if (i >= NDFILE) { free(newfdp->fd_ofiles, M_FILEDESC); } if (NDHISLOTS(i) > NDHISLOTS(NDFILE)) { free(newfdp->fd_himap, M_FILEDESC); free(newfdp->fd_lomap, M_FILEDESC); } while (fflist != NULL) { ff = fflist; fflist = (void *)ff->ff_file; ff->ff_file = NULL; pool_cache_put(fdfile_cache, ff); } } newfdp->fd_nfiles = i; newfdp->fd_freefile = fdp->fd_freefile; newfdp->fd_exclose = fdp->fd_exclose; /* * Clear the entries that will not be copied over. * Avoid calling memset with 0 size. */ if (lastfile < (i-1)) { memset(newfdp->fd_ofiles + lastfile + 1, 0, (i - lastfile - 1) * sizeof(file_t **)); } if (i < NDENTRIES * NDENTRIES) { i = NDENTRIES * NDENTRIES; /* size of inlined bitmaps */ } memcpy(newfdp->fd_himap, fdp->fd_himap, NDHISLOTS(i)*sizeof(uint32_t)); memcpy(newfdp->fd_lomap, fdp->fd_lomap, NDLOSLOTS(i)*sizeof(uint32_t)); ffp = fdp->fd_ofiles; nffp = newfdp->fd_ofiles; j = imax(lastfile, (NDFDFILE - 1)); newlast = -1; KASSERT(j < fdp->fd_nfiles); for (i = 0; i <= j; i++, ffp++, *nffp++ = ff2) { ff = *ffp; /* Install built-in fdfiles even if unused here. */ if (i < NDFDFILE) { ff2 = (fdfile_t *)newfdp->fd_dfdfile[i]; } else { ff2 = NULL; } /* Determine if descriptor is active in parent. */ if (ff == NULL || !fd_isused(fdp, i)) { KASSERT(ff != NULL || i >= NDFDFILE); continue; } mutex_enter(&ff->ff_lock); fp = ff->ff_file; if (fp == NULL) { /* Descriptor is half-open: free slot. */ fd_zap(newfdp, i); mutex_exit(&ff->ff_lock); continue; } if (fp->f_type == DTYPE_KQUEUE) { /* kqueue descriptors cannot be copied. */ fd_zap(newfdp, i); mutex_exit(&ff->ff_lock); continue; } /* It's active: add a reference to the file. */ mutex_enter(&fp->f_lock); fp->f_count++; mutex_exit(&fp->f_lock); /* Consume one fdfile_t to represent it. */ if (i >= NDFDFILE) { ff2 = fflist; fflist = (void *)ff2->ff_file; } ff2->ff_file = fp; ff2->ff_exclose = ff->ff_exclose; ff2->ff_allocated = true; mutex_exit(&ff->ff_lock); if (i > newlast) { newlast = i; } } mutex_exit(&fdp->fd_lock); /* Discard unused fdfile_t structures. */ while (__predict_false(fflist != NULL)) { ff = fflist; fflist = (void *)ff->ff_file; ff->ff_file = NULL; pool_cache_put(fdfile_cache, ff); nused--; } KASSERT(nused >= 0); KASSERT(newfdp->fd_ofiles[0] == (fdfile_t *)newfdp->fd_dfdfile[0]); newfdp->fd_nused = nused; newfdp->fd_lastfile = newlast; return (newfdp); } /* * Release a filedesc structure. */ void fd_free(void) { filedesc_t *fdp; fdfile_t *ff; file_t *fp; int fd, lastfd; void *discard; fdp = curlwp->l_fd; KASSERT(fdp->fd_ofiles[0] == (fdfile_t *)fdp->fd_dfdfile[0]); if (atomic_dec_uint_nv(&fdp->fd_refcnt) > 0) return; /* * Close any files that the process holds open. */ for (fd = 0, lastfd = fdp->fd_nfiles - 1; fd <= lastfd; fd++) { ff = fdp->fd_ofiles[fd]; KASSERT(fd >= NDFDFILE || ff == (fdfile_t *)fdp->fd_dfdfile[fd]); if ((ff = fdp->fd_ofiles[fd]) == NULL) continue; if ((fp = ff->ff_file) != NULL) { /* * Must use fd_close() here as kqueue holds * long term references to descriptors. */ ff->ff_refcnt++; fd_close(fd); } KASSERT(ff->ff_refcnt == 0); KASSERT(ff->ff_file == NULL); KASSERT(!ff->ff_exclose); KASSERT(!ff->ff_allocated); if (fd >= NDFDFILE) { pool_cache_put(fdfile_cache, ff); } } /* * Clean out the descriptor table for the next user and return * to the cache. */ while ((discard = fdp->fd_discard) != NULL) { KASSERT(discard != fdp->fd_ofiles); fdp->fd_discard = *(void **)discard; free(discard, M_FILEDESC); } if (NDHISLOTS(fdp->fd_nfiles) > NDHISLOTS(NDFILE)) { KASSERT(fdp->fd_himap != fdp->fd_dhimap); KASSERT(fdp->fd_lomap != fdp->fd_dlomap); free(fdp->fd_himap, M_FILEDESC); free(fdp->fd_lomap, M_FILEDESC); } if (fdp->fd_nfiles > NDFILE) { KASSERT(fdp->fd_ofiles != fdp->fd_dfiles); free(fdp->fd_ofiles, M_FILEDESC); } if (fdp->fd_knhash != NULL) { hashdone(fdp->fd_knhash, HASH_LIST, fdp->fd_knhashmask); fdp->fd_knhash = NULL; fdp->fd_knhashmask = 0; } else { KASSERT(fdp->fd_knhashmask == 0); } fdp->fd_lastkqfile = -1; pool_cache_put(filedesc_cache, fdp); } /* * File Descriptor pseudo-device driver (/dev/fd/). * * Opening minor device N dup()s the file (if any) connected to file * descriptor N belonging to the calling process. Note that this driver * consists of only the ``open()'' routine, because all subsequent * references to this file will be direct to the other driver. */ static int filedescopen(dev_t dev, int mode, int type, lwp_t *l) { /* * XXX Kludge: set dupfd to contain the value of the * the file descriptor being sought for duplication. The error * return ensures that the vnode for this device will be released * by vn_open. Open will detect this special error and take the * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN * will simply report the error. */ l->l_dupfd = minor(dev); /* XXX */ return EDUPFD; } /* * Duplicate the specified descriptor to a free descriptor. */ int fd_dupopen(int old, int *new, int mode, int error) { filedesc_t *fdp; fdfile_t *ff; file_t *fp; if ((fp = fd_getfile(old)) == NULL) { return EBADF; } fdp = curlwp->l_fd; ff = fdp->fd_ofiles[old]; /* * There are two cases of interest here. * * For EDUPFD simply dup (dfd) to file descriptor * (indx) and return. * * For EMOVEFD steal away the file structure from (dfd) and * store it in (indx). (dfd) is effectively closed by * this operation. * * Any other error code is just returned. */ switch (error) { case EDUPFD: /* * Check that the mode the file is being opened for is a * subset of the mode of the existing descriptor. */ if (((mode & (FREAD|FWRITE)) | fp->f_flag) != fp->f_flag) { error = EACCES; break; } /* Copy it. */ error = fd_dup(fp, 0, new, fdp->fd_ofiles[old]->ff_exclose); break; case EMOVEFD: /* Copy it. */ error = fd_dup(fp, 0, new, fdp->fd_ofiles[old]->ff_exclose); if (error != 0) { break; } /* Steal away the file pointer from 'old'. */ (void)fd_close(old); return 0; } fd_putfile(old); return error; } /* * Sets descriptor owner. If the owner is a process, 'pgid' * is set to positive value, process ID. If the owner is process group, * 'pgid' is set to -pg_id. */ int fsetown(pid_t *pgid, u_long cmd, const void *data) { int id = *(const int *)data; int error; switch (cmd) { case TIOCSPGRP: if (id < 0) return (EINVAL); id = -id; break; default: break; } if (id > 0 && !pfind(id)) return (ESRCH); else if (id < 0 && (error = pgid_in_session(curproc, -id))) return (error); *pgid = id; return (0); } /* * Return descriptor owner information. If the value is positive, * it's process ID. If it's negative, it's process group ID and * needs the sign removed before use. */ int fgetown(pid_t pgid, u_long cmd, void *data) { switch (cmd) { case TIOCGPGRP: *(int *)data = -pgid; break; default: *(int *)data = pgid; break; } return (0); } /* * Send signal to descriptor owner, either process or process group. */ void fownsignal(pid_t pgid, int signo, int code, int band, void *fdescdata) { struct proc *p1; struct pgrp *pgrp; ksiginfo_t ksi; KASSERT(!cpu_intr_p()); KSI_INIT(&ksi); ksi.ksi_signo = signo; ksi.ksi_code = code; ksi.ksi_band = band; mutex_enter(proc_lock); if (pgid > 0 && (p1 = p_find(pgid, PFIND_LOCKED))) kpsignal(p1, &ksi, fdescdata); else if (pgid < 0 && (pgrp = pg_find(-pgid, PFIND_LOCKED))) kpgsignal(pgrp, &ksi, fdescdata, 0); mutex_exit(proc_lock); } int fd_clone(file_t *fp, unsigned fd, int flag, const struct fileops *fops, void *data) { fp->f_flag = flag; fp->f_type = DTYPE_MISC; fp->f_ops = fops; fp->f_data = data; curlwp->l_dupfd = fd; fd_affix(curproc, fp, fd); return EMOVEFD; } int fnullop_fcntl(file_t *fp, u_int cmd, void *data) { if (cmd == F_SETFL) return 0; return EOPNOTSUPP; } int fnullop_poll(file_t *fp, int which) { return 0; } int fnullop_kqfilter(file_t *fp, struct knote *kn) { return 0; } int fbadop_read(file_t *fp, off_t *offset, struct uio *uio, kauth_cred_t cred, int flags) { return EOPNOTSUPP; } int fbadop_write(file_t *fp, off_t *offset, struct uio *uio, kauth_cred_t cred, int flags) { return EOPNOTSUPP; } int fbadop_ioctl(file_t *fp, u_long com, void *data) { return EOPNOTSUPP; } int fbadop_stat(file_t *fp, struct stat *sb) { return EOPNOTSUPP; } int fbadop_close(file_t *fp) { return EOPNOTSUPP; }