X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/c0fea4742e91338fffdcf79f86a7c1d5e2b97eb1..7e41aa883dd258f888d0470250eead40a53ef1f5:/bsd/kern/sys_pipe.c?ds=inline diff --git a/bsd/kern/sys_pipe.c b/bsd/kern/sys_pipe.c index d9c75707c..1e64ce737 100644 --- a/bsd/kern/sys_pipe.c +++ b/bsd/kern/sys_pipe.c @@ -17,25 +17,37 @@ * are met. */ /* - * Copyright (c) 2003-2004 Apple Computer, Inc. All rights reserved. + * Copyright (c) 2003-2014 Apple Inc. All rights reserved. * - * @APPLE_LICENSE_HEADER_START@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * - * The contents of this file constitute Original Code as defined in and - * are subject to the Apple Public Source License Version 1.1 (the - * "License"). You may not use this file except in compliance with the - * License. Please obtain a copy of the License at - * http://www.apple.com/publicsource and read it before using this file. + * This file contains Original Code and/or Modifications of Original Code + * as defined in and that are subject to the Apple Public Source License + * Version 2.0 (the 'License'). You may not use this file except in + * compliance with the License. The rights granted to you under the License + * may not be used to create, or enable the creation or redistribution of, + * unlawful or unlicensed copies of an Apple operating system, or to + * circumvent, violate, or enable the circumvention or violation of, any + * terms of an Apple operating system software license agreement. * - * This Original Code and all software distributed under the License are - * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * Please obtain a copy of the License at + * http://www.opensource.apple.com/apsl/ and read it before using this file. + * + * The Original Code and all software distributed under the License are + * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the - * License for the specific language governing rights and limitations - * under the License. + * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. + * Please see the License for the specific language governing rights and + * limitations under the License. * - * @APPLE_LICENSE_HEADER_END@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ + */ +/* + * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce + * support for mandatory and extensible security protections. This notice + * is included in support of clause 2.2 (b) of the Apple Public License, + * Version 2.0. */ /* @@ -43,46 +55,65 @@ * pipes scheme originally used in FreeBSD/4.4Lite. It does not support * all features of sockets, but does do everything that pipes normally * do. + * + * Pipes are implemented as circular buffers. Following are the valid states in pipes operations + * + * _________________________________ + * 1. |_________________________________| r=w, c=0 + * + * _________________________________ + * 2. |__r:::::wc_______________________| r <= w , c > 0 + * + * _________________________________ + * 3. |::::wc_____r:::::::::::::::::::::| r>w , c > 0 + * + * _________________________________ + * 4. |:::::::wrc:::::::::::::::::::::::| w=r, c = Max size + * + * + * Nomenclature:- + * a-z define the steps in a program flow + * 1-4 are the states as defined aboe + * Action: is what file operation is done on the pipe + * + * Current:None Action: initialize with size M=200 + * a. State 1 ( r=0, w=0, c=0) + * + * Current: a Action: write(100) (w < M) + * b. State 2 (r=0, w=100, c=100) + * + * Current: b Action: write(100) (w = M-w) + * c. State 4 (r=0,w=0,c=200) + * + * Current: b Action: read(70) ( r < c ) + * d. State 2(r=70,w=100,c=30) + * + * Current: d Action: write(75) ( w < (m-w)) + * e. State 2 (r=70,w=175,c=105) + * + * Current: d Action: write(110) ( w > (m-w)) + * f. State 3 (r=70,w=10,c=140) + * + * Current: d Action: read(30) (r >= c ) + * g. State 1 (r=100,w=100,c=0) + * */ /* - * This code has two modes of operation, a small write mode and a large - * write mode. The small write mode acts like conventional pipes with - * a kernel buffer. If the buffer is less than PIPE_MINDIRECT, then the - * "normal" pipe buffering is done. If the buffer is between PIPE_MINDIRECT - * and PIPE_SIZE in size, it is fully mapped and wired into the kernel, and - * the receiving process can copy it directly from the pages in the sending - * process. - * - * If the sending process receives a signal, it is possible that it will - * go away, and certainly its address space can change, because control - * is returned back to the user-mode side. In that case, the pipe code - * arranges to copy the buffer supplied by the user process, to a pageable - * kernel buffer, and the receiving process will grab the data from the - * pageable kernel buffer. Since signals don't happen all that often, - * the copy operation is normally eliminated. - * - * The constant PIPE_MINDIRECT is chosen to make sure that buffering will - * happen for small transfers so that the system will not spend all of - * its time context switching. + * This code create half duplex pipe buffers for facilitating file like + * operations on pipes. The initial buffer is very small, but this can + * dynamically change to larger sizes based on usage. The buffer size is never + * reduced. The total amount of kernel memory used is governed by maxpipekva. + * In case of dynamic expansion limit is reached, the output thread is blocked + * until the pipe buffer empties enough to continue. * * In order to limit the resource use of pipes, two sysctls exist: * * kern.ipc.maxpipekva - This is a hard limit on the amount of pageable - * address space available to us in pipe_map. Whenever the amount in use - * exceeds half of this value, all new pipes will be created with size - * SMALL_PIPE_SIZE, rather than PIPE_SIZE. Big pipe creation will be limited - * as well. This value is loader tunable only. - * - * kern.ipc.maxpipekvawired - This value limits the amount of memory that may - * be wired in order to facilitate direct copies using page flipping. - * Whenever this value is exceeded, pipes will fall back to using regular - * copies. This value is sysctl controllable at all times. - * - * These values are autotuned in subr_param.c. + * address space available to us in pipe_map. * * Memory usage may be monitored through the sysctls - * kern.ipc.pipes, kern.ipc.pipekva and kern.ipc.pipekvawired. + * kern.ipc.pipes, kern.ipc.pipekva. * */ @@ -107,177 +138,270 @@ #include #include -#include +#include #include #include +#include #include #include #define f_flag f_fglob->fg_flag -#define f_type f_fglob->fg_type #define f_msgcount f_fglob->fg_msgcount #define f_cred f_fglob->fg_cred #define f_ops f_fglob->fg_ops #define f_offset f_fglob->fg_offset #define f_data f_fglob->fg_data -/* - * Use this define if you want to disable *fancy* VM things. Expect an - * approx 30% decrease in transfer rate. This could be useful for - * NetBSD or OpenBSD. - * - * this needs to be ported to X and the performance measured - * before committing to supporting it - */ -#define PIPE_NODIRECT 1 - -#ifndef PIPE_NODIRECT - -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#endif - /* - * interfaces to the outside world + * interfaces to the outside world exported through file operations */ static int pipe_read(struct fileproc *fp, struct uio *uio, - kauth_cred_t cred, int flags, struct proc *p); - + int flags, vfs_context_t ctx); static int pipe_write(struct fileproc *fp, struct uio *uio, - kauth_cred_t cred, int flags, struct proc *p); - -static int pipe_close(struct fileglob *fg, struct proc *p); - -static int pipe_select(struct fileproc *fp, int which, void * wql, struct proc *p); - -static int pipe_kqfilter(struct fileproc *fp, struct knote *kn, struct proc *p); - -static int pipe_ioctl(struct fileproc *fp, u_long cmd, caddr_t data, struct proc *p); - - -struct fileops pipeops = - { pipe_read, - pipe_write, - pipe_ioctl, - pipe_select, - pipe_close, - pipe_kqfilter, - 0 }; - + int flags, vfs_context_t ctx); +static int pipe_close(struct fileglob *fg, vfs_context_t ctx); +static int pipe_select(struct fileproc *fp, int which, void * wql, + vfs_context_t ctx); +static int pipe_kqfilter(struct fileproc *fp, struct knote *kn, + vfs_context_t ctx); +static int pipe_ioctl(struct fileproc *fp, u_long cmd, caddr_t data, + vfs_context_t ctx); +static int pipe_drain(struct fileproc *fp,vfs_context_t ctx); + +static const struct fileops pipeops = { + DTYPE_PIPE, + pipe_read, + pipe_write, + pipe_ioctl, + pipe_select, + pipe_close, + pipe_kqfilter, + pipe_drain +}; static void filt_pipedetach(struct knote *kn); static int filt_piperead(struct knote *kn, long hint); static int filt_pipewrite(struct knote *kn, long hint); -static struct filterops pipe_rfiltops = - { 1, NULL, filt_pipedetach, filt_piperead }; -static struct filterops pipe_wfiltops = - { 1, NULL, filt_pipedetach, filt_pipewrite }; +static struct filterops pipe_rfiltops = { + .f_isfd = 1, + .f_detach = filt_pipedetach, + .f_event = filt_piperead, +}; -/* - * Default pipe buffer size(s), this can be kind-of large now because pipe - * space is pageable. The pipe code will try to maintain locality of - * reference for performance reasons, so small amounts of outstanding I/O - * will not wipe the cache. - */ -#define MINPIPESIZE (PIPE_SIZE/3) +static struct filterops pipe_wfiltops = { + .f_isfd = 1, + .f_detach = filt_pipedetach, + .f_event = filt_pipewrite, +}; -/* - * Limit the number of "big" pipes - */ -#define LIMITBIGPIPES 32 -static int nbigpipe; +static int nbigpipe; /* for compatibility sake. no longer used */ +static int amountpipes; /* total number of pipes in system */ +static int amountpipekva; /* total memory used by pipes */ -static int amountpipes; -static int amountpipekva; - -#ifndef PIPE_NODIRECT -static int amountpipekvawired; -#endif -int maxpipekva = 1024 * 1024 * 16; +int maxpipekva __attribute__((used)) = PIPE_KVAMAX; /* allowing 16MB max. */ #if PIPE_SYSCTLS SYSCTL_DECL(_kern_ipc); -SYSCTL_INT(_kern_ipc, OID_AUTO, maxpipekva, CTLFLAG_RD, +SYSCTL_INT(_kern_ipc, OID_AUTO, maxpipekva, CTLFLAG_RD|CTLFLAG_LOCKED, &maxpipekva, 0, "Pipe KVA limit"); -SYSCTL_INT(_kern_ipc, OID_AUTO, maxpipekvawired, CTLFLAG_RW, +SYSCTL_INT(_kern_ipc, OID_AUTO, maxpipekvawired, CTLFLAG_RW|CTLFLAG_LOCKED, &maxpipekvawired, 0, "Pipe KVA wired limit"); -SYSCTL_INT(_kern_ipc, OID_AUTO, pipes, CTLFLAG_RD, +SYSCTL_INT(_kern_ipc, OID_AUTO, pipes, CTLFLAG_RD|CTLFLAG_LOCKED, &amountpipes, 0, "Current # of pipes"); -SYSCTL_INT(_kern_ipc, OID_AUTO, bigpipes, CTLFLAG_RD, +SYSCTL_INT(_kern_ipc, OID_AUTO, bigpipes, CTLFLAG_RD|CTLFLAG_LOCKED, &nbigpipe, 0, "Current # of big pipes"); -SYSCTL_INT(_kern_ipc, OID_AUTO, pipekva, CTLFLAG_RD, +SYSCTL_INT(_kern_ipc, OID_AUTO, pipekva, CTLFLAG_RD|CTLFLAG_LOCKED, &amountpipekva, 0, "Pipe KVA usage"); -SYSCTL_INT(_kern_ipc, OID_AUTO, pipekvawired, CTLFLAG_RD, +SYSCTL_INT(_kern_ipc, OID_AUTO, pipekvawired, CTLFLAG_RD|CTLFLAG_LOCKED, &amountpipekvawired, 0, "Pipe wired KVA usage"); #endif -void pipeinit(void *dummy __unused); static void pipeclose(struct pipe *cpipe); static void pipe_free_kmem(struct pipe *cpipe); static int pipe_create(struct pipe **cpipep); +static int pipespace(struct pipe *cpipe, int size); +static int choose_pipespace(unsigned long current, unsigned long expected); +static int expand_pipespace(struct pipe *p, int target_size); static void pipeselwakeup(struct pipe *cpipe, struct pipe *spipe); -static __inline int pipelock(struct pipe *cpipe, int catch); -static __inline void pipeunlock(struct pipe *cpipe); - -#ifndef PIPE_NODIRECT -static int pipe_build_write_buffer(struct pipe *wpipe, struct uio *uio); -static void pipe_destroy_write_buffer(struct pipe *wpipe); -static int pipe_direct_write(struct pipe *wpipe, struct uio *uio); -static void pipe_clone_write_buffer(struct pipe *wpipe); -#endif +static __inline int pipeio_lock(struct pipe *cpipe, int catch); +static __inline void pipeio_unlock(struct pipe *cpipe); extern int postpipeevent(struct pipe *, int); extern void evpipefree(struct pipe *cpipe); - -static int pipespace(struct pipe *cpipe, int size); - static lck_grp_t *pipe_mtx_grp; static lck_attr_t *pipe_mtx_attr; static lck_grp_attr_t *pipe_mtx_grp_attr; static zone_t pipe_zone; +#define MAX_PIPESIZE(pipe) ( MAX(PIPE_SIZE, (pipe)->pipe_buffer.size) ) + +#define PIPE_GARBAGE_AGE_LIMIT 5000 /* In milliseconds */ +#define PIPE_GARBAGE_QUEUE_LIMIT 32000 + +struct pipe_garbage { + struct pipe *pg_pipe; + struct pipe_garbage *pg_next; + uint64_t pg_timestamp; +}; + +static zone_t pipe_garbage_zone; +static struct pipe_garbage *pipe_garbage_head = NULL; +static struct pipe_garbage *pipe_garbage_tail = NULL; +static uint64_t pipe_garbage_age_limit = PIPE_GARBAGE_AGE_LIMIT; +static int pipe_garbage_count = 0; +static lck_mtx_t *pipe_garbage_lock; +static void pipe_garbage_collect(struct pipe *cpipe); + SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_ANY, pipeinit, NULL); +/* initial setup done at time of sysinit */ void -pipeinit(void *dummy __unused) +pipeinit(void) { - pipe_zone = (zone_t)zinit(sizeof(struct pipe), 8192 * sizeof(struct pipe), 4096, "pipe zone"); + nbigpipe=0; + vm_size_t zone_size; + + zone_size = 8192 * sizeof(struct pipe); + pipe_zone = zinit(sizeof(struct pipe), zone_size, 4096, "pipe zone"); - /* - * allocate lock group attribute and group for pipe mutexes - */ + + /* allocate lock group attribute and group for pipe mutexes */ pipe_mtx_grp_attr = lck_grp_attr_alloc_init(); pipe_mtx_grp = lck_grp_alloc_init("pipe", pipe_mtx_grp_attr); + /* allocate the lock attribute for pipe mutexes */ + pipe_mtx_attr = lck_attr_alloc_init(); + /* - * allocate the lock attribute for pipe mutexes + * Set up garbage collection for dead pipes */ - pipe_mtx_attr = lck_attr_alloc_init(); + zone_size = (PIPE_GARBAGE_QUEUE_LIMIT + 20) * + sizeof(struct pipe_garbage); + pipe_garbage_zone = (zone_t)zinit(sizeof(struct pipe_garbage), + zone_size, 4096, "pipe garbage zone"); + pipe_garbage_lock = lck_mtx_alloc_init(pipe_mtx_grp, pipe_mtx_attr); + } +/* Bitmap for things to touch in pipe_touch() */ +#define PIPE_ATIME 0x00000001 /* time of last access */ +#define PIPE_MTIME 0x00000002 /* time of last modification */ +#define PIPE_CTIME 0x00000004 /* time of last status change */ + +static void +pipe_touch(struct pipe *tpipe, int touch) +{ + struct timeval now; + + microtime(&now); + + if (touch & PIPE_ATIME) { + tpipe->st_atimespec.tv_sec = now.tv_sec; + tpipe->st_atimespec.tv_nsec = now.tv_usec * 1000; + } + + if (touch & PIPE_MTIME) { + tpipe->st_mtimespec.tv_sec = now.tv_sec; + tpipe->st_mtimespec.tv_nsec = now.tv_usec * 1000; + } + + if (touch & PIPE_CTIME) { + tpipe->st_ctimespec.tv_sec = now.tv_sec; + tpipe->st_ctimespec.tv_nsec = now.tv_usec * 1000; + } +} + +static const unsigned int pipesize_blocks[] = {512,1024,2048,4096, 4096 * 2, PIPE_SIZE , PIPE_SIZE * 4 }; + +/* + * finds the right size from possible sizes in pipesize_blocks + * returns the size which matches max(current,expected) + */ +static int +choose_pipespace(unsigned long current, unsigned long expected) +{ + int i = sizeof(pipesize_blocks)/sizeof(unsigned int) -1; + unsigned long target; + + /* + * assert that we always get an atomic transaction sized pipe buffer, + * even if the system pipe buffer high-water mark has been crossed. + */ + assert(PIPE_BUF == pipesize_blocks[0]); + + if (expected > current) + target = expected; + else + target = current; + + while ( i >0 && pipesize_blocks[i-1] > target) { + i=i-1; + + } + + return pipesize_blocks[i]; +} + + +/* + * expand the size of pipe while there is data to be read, + * and then free the old buffer once the current buffered + * data has been transferred to new storage. + * Required: PIPE_LOCK and io lock to be held by caller. + * returns 0 on success or no expansion possible + */ +static int +expand_pipespace(struct pipe *p, int target_size) +{ + struct pipe tmp, oldpipe; + int error; + tmp.pipe_buffer.buffer = 0; + + if (p->pipe_buffer.size >= (unsigned) target_size) { + return 0; /* the existing buffer is max size possible */ + } + + /* create enough space in the target */ + error = pipespace(&tmp, target_size); + if (error != 0) + return (error); + + oldpipe.pipe_buffer.buffer = p->pipe_buffer.buffer; + oldpipe.pipe_buffer.size = p->pipe_buffer.size; + + memcpy(tmp.pipe_buffer.buffer, p->pipe_buffer.buffer, p->pipe_buffer.size); + if (p->pipe_buffer.cnt > 0 && p->pipe_buffer.in <= p->pipe_buffer.out ){ + /* we are in State 3 and need extra copying for read to be consistent */ + memcpy(&tmp.pipe_buffer.buffer[p->pipe_buffer.size], p->pipe_buffer.buffer, p->pipe_buffer.size); + p->pipe_buffer.in += p->pipe_buffer.size; + } + + p->pipe_buffer.buffer = tmp.pipe_buffer.buffer; + p->pipe_buffer.size = tmp.pipe_buffer.size; + pipe_free_kmem(&oldpipe); + return 0; +} + /* * The pipe system call for the DTYPE_PIPE type of pipes + * + * returns: + * FREAD | fd0 | -->[struct rpipe] --> |~~buffer~~| \ + * (pipe_mutex) + * FWRITE | fd1 | -->[struct wpipe] --X / */ /* ARGSUSED */ int -pipe(struct proc *p, __unused struct pipe_args *uap, register_t *retval) +pipe(proc_t p, __unused struct pipe_args *uap, int32_t *retval) { struct fileproc *rf, *wf; struct pipe *rpipe, *wpipe; @@ -295,75 +419,64 @@ pipe(struct proc *p, __unused struct pipe_args *uap, register_t *retval) /* * allocate the space for the normal I/O direction up * front... we'll delay the allocation for the other - * direction until a write actually occurs (most - * likely it won't)... - * - * Reduce to 1/4th pipe size if we're over our global max. + * direction until a write actually occurs (most likely it won't)... */ - if (amountpipekva > maxpipekva / 2) - error = pipespace(rpipe, SMALL_PIPE_SIZE); - else - error = pipespace(rpipe, PIPE_SIZE); + error = pipespace(rpipe, choose_pipespace(rpipe->pipe_buffer.size, 0)); if (error) goto freepipes; -#ifndef PIPE_NODIRECT - rpipe->pipe_state |= PIPE_DIRECTOK; - wpipe->pipe_state |= PIPE_DIRECTOK; -#endif TAILQ_INIT(&rpipe->pipe_evlist); TAILQ_INIT(&wpipe->pipe_evlist); - error = falloc(p, &rf, &fd); + error = falloc(p, &rf, &fd, vfs_context_current()); if (error) { goto freepipes; } retval[0] = fd; /* - * for now we'll create half-duplex - * pipes... this is what we've always - * supported.. + * for now we'll create half-duplex pipes(refer returns section above). + * this is what we've always supported.. */ rf->f_flag = FREAD; - rf->f_type = DTYPE_PIPE; rf->f_data = (caddr_t)rpipe; rf->f_ops = &pipeops; - error = falloc(p, &wf, &fd); + error = falloc(p, &wf, &fd, vfs_context_current()); if (error) { fp_free(p, retval[0], rf); goto freepipes; } wf->f_flag = FWRITE; - wf->f_type = DTYPE_PIPE; wf->f_data = (caddr_t)wpipe; wf->f_ops = &pipeops; + rpipe->pipe_peer = wpipe; + wpipe->pipe_peer = rpipe; + /* both structures share the same mutex */ + rpipe->pipe_mtxp = wpipe->pipe_mtxp = pmtx; + retval[1] = fd; -#ifdef MAC +#if CONFIG_MACF /* * XXXXXXXX SHOULD NOT HOLD FILE_LOCK() XXXXXXXXXXXX * * struct pipe represents a pipe endpoint. The MAC label is shared - * between the connected endpoints. As a result mac_init_pipe() and - * mac_create_pipe() should only be called on one of the endpoints + * between the connected endpoints. As a result mac_pipe_label_init() and + * mac_pipe_label_associate() should only be called on one of the endpoints * after they have been connected. */ - mac_init_pipe(rpipe); - mac_create_pipe(td->td_ucred, rpipe); + mac_pipe_label_init(rpipe); + mac_pipe_label_associate(kauth_cred_get(), rpipe); + wpipe->pipe_label = rpipe->pipe_label; #endif - proc_fdlock(p); - *fdflags(p, retval[0]) &= ~UF_RESERVED; - *fdflags(p, retval[1]) &= ~UF_RESERVED; + proc_fdlock_spin(p); + procfdtbl_releasefd(p, retval[0], NULL); + procfdtbl_releasefd(p, retval[1], NULL); fp_drop(p, retval[0], rf, 1); fp_drop(p, retval[1], wf, 1); proc_fdunlock(p); - rpipe->pipe_peer = wpipe; - wpipe->pipe_peer = rpipe; - - rpipe->pipe_mtxp = wpipe->pipe_mtxp = pmtx; return (0); @@ -375,56 +488,112 @@ freepipes: return (error); } - int -pipe_stat(struct pipe *cpipe, struct stat *ub) +pipe_stat(struct pipe *cpipe, void *ub, int isstat64) { -#ifdef MAC +#if CONFIG_MACF int error; #endif - struct timeval now; + int pipe_size = 0; + int pipe_count; + struct stat *sb = (struct stat *)0; /* warning avoidance ; protected by isstat64 */ + struct stat64 * sb64 = (struct stat64 *)0; /* warning avoidance ; protected by isstat64 */ if (cpipe == NULL) return (EBADF); -#ifdef MAC PIPE_LOCK(cpipe); - error = mac_check_pipe_stat(active_cred, cpipe); - PIPE_UNLOCK(cpipe); - if (error) + +#if CONFIG_MACF + error = mac_pipe_check_stat(kauth_cred_get(), cpipe); + if (error) { + PIPE_UNLOCK(cpipe); return (error); + } #endif if (cpipe->pipe_buffer.buffer == 0) { - /* - * must be stat'ing the write fd - */ - cpipe = cpipe->pipe_peer; - - if (cpipe == NULL) - return (EBADF); + /* must be stat'ing the write fd */ + if (cpipe->pipe_peer) { + /* the peer still exists, use it's info */ + pipe_size = MAX_PIPESIZE(cpipe->pipe_peer); + pipe_count = cpipe->pipe_peer->pipe_buffer.cnt; + } else { + pipe_count = 0; + } + } else { + pipe_size = MAX_PIPESIZE(cpipe); + pipe_count = cpipe->pipe_buffer.cnt; } - bzero(ub, sizeof(*ub)); - ub->st_mode = S_IFIFO | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP; - ub->st_blksize = cpipe->pipe_buffer.size; - ub->st_size = cpipe->pipe_buffer.cnt; - ub->st_blocks = (ub->st_size + ub->st_blksize - 1) / ub->st_blksize; - ub->st_nlink = 1; + /* + * since peer's buffer is setup ouside of lock + * we might catch it in transient state + */ + if (pipe_size == 0) + pipe_size = MAX(PIPE_SIZE, pipesize_blocks[0]); - ub->st_uid = kauth_getuid(); - ub->st_gid = kauth_getgid(); + if (isstat64 != 0) { + sb64 = (struct stat64 *)ub; - microtime(&now); - ub->st_atimespec.tv_sec = now.tv_sec; - ub->st_atimespec.tv_nsec = now.tv_usec * 1000; + bzero(sb64, sizeof(*sb64)); + sb64->st_mode = S_IFIFO | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP; + sb64->st_blksize = pipe_size; + sb64->st_size = pipe_count; + sb64->st_blocks = (sb64->st_size + sb64->st_blksize - 1) / sb64->st_blksize; + + sb64->st_uid = kauth_getuid(); + sb64->st_gid = kauth_getgid(); + + sb64->st_atimespec.tv_sec = cpipe->st_atimespec.tv_sec; + sb64->st_atimespec.tv_nsec = cpipe->st_atimespec.tv_nsec; + + sb64->st_mtimespec.tv_sec = cpipe->st_mtimespec.tv_sec; + sb64->st_mtimespec.tv_nsec = cpipe->st_mtimespec.tv_nsec; + + sb64->st_ctimespec.tv_sec = cpipe->st_ctimespec.tv_sec; + sb64->st_ctimespec.tv_nsec = cpipe->st_ctimespec.tv_nsec; + + /* + * Return a relatively unique inode number based on the current + * address of this pipe's struct pipe. This number may be recycled + * relatively quickly. + */ + sb64->st_ino = (ino64_t)VM_KERNEL_ADDRPERM((uintptr_t)cpipe); + } else { + sb = (struct stat *)ub; + + bzero(sb, sizeof(*sb)); + sb->st_mode = S_IFIFO | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP; + sb->st_blksize = pipe_size; + sb->st_size = pipe_count; + sb->st_blocks = (sb->st_size + sb->st_blksize - 1) / sb->st_blksize; + + sb->st_uid = kauth_getuid(); + sb->st_gid = kauth_getgid(); + + sb->st_atimespec.tv_sec = cpipe->st_atimespec.tv_sec; + sb->st_atimespec.tv_nsec = cpipe->st_atimespec.tv_nsec; + + sb->st_mtimespec.tv_sec = cpipe->st_mtimespec.tv_sec; + sb->st_mtimespec.tv_nsec = cpipe->st_mtimespec.tv_nsec; - ub->st_mtimespec.tv_sec = now.tv_sec; - ub->st_mtimespec.tv_nsec = now.tv_usec * 1000; + sb->st_ctimespec.tv_sec = cpipe->st_ctimespec.tv_sec; + sb->st_ctimespec.tv_nsec = cpipe->st_ctimespec.tv_nsec; - ub->st_ctimespec.tv_sec = now.tv_sec; - ub->st_ctimespec.tv_nsec = now.tv_usec * 1000; + /* + * Return a relatively unique inode number based on the current + * address of this pipe's struct pipe. This number may be recycled + * relatively quickly. + */ + sb->st_ino = (ino_t)VM_KERNEL_ADDRPERM((uintptr_t)cpipe); + } + PIPE_UNLOCK(cpipe); /* - * Left as 0: st_dev, st_ino, st_nlink, st_rdev, st_flags, st_gen, st_uid, st_gid. - * XXX (st_dev, st_ino) should be unique. + * POSIX: Left as 0: st_dev, st_nlink, st_rdev, st_flags, st_gen, + * st_uid, st_gid. + * + * XXX (st_dev) should be unique, but there is no device driver that + * XXX is associated with pipes, since they are implemented via a + * XXX struct fileops indirection rather than as FS objects. */ return (0); } @@ -441,10 +610,11 @@ pipespace(struct pipe *cpipe, int size) { vm_offset_t buffer; - size = round_page(size); + if (size <= 0) + return(EINVAL); - if (kmem_alloc(kernel_map, &buffer, size) != KERN_SUCCESS) - return(ENOMEM); + if ((buffer = (vm_offset_t)kalloc(size)) == 0 ) + return(ENOMEM); /* free old resources if we're resizing */ pipe_free_kmem(cpipe); @@ -454,8 +624,8 @@ pipespace(struct pipe *cpipe, int size) cpipe->pipe_buffer.out = 0; cpipe->pipe_buffer.cnt = 0; - OSAddAtomic(1, (SInt32 *)&amountpipes); - OSAddAtomic(cpipe->pipe_buffer.size, (SInt32 *)&amountpipekva); + OSAddAtomic(1, &amountpipes); + OSAddAtomic(cpipe->pipe_buffer.size, &amountpipekva); return (0); } @@ -467,7 +637,6 @@ static int pipe_create(struct pipe **cpipep) { struct pipe *cpipe; - cpipe = (struct pipe *)zalloc(pipe_zone); if ((*cpipep = cpipe) == NULL) @@ -479,6 +648,8 @@ pipe_create(struct pipe **cpipep) */ bzero(cpipe, sizeof *cpipe); + /* Initial times are all the time of creation of the pipe */ + pipe_touch(cpipe, PIPE_ATIME | PIPE_MTIME | PIPE_CTIME); return (0); } @@ -486,48 +657,40 @@ pipe_create(struct pipe **cpipep) /* * lock a pipe for I/O, blocking other access */ -static __inline int -pipelock(cpipe, catch) - struct pipe *cpipe; - int catch; +static inline int +pipeio_lock(struct pipe *cpipe, int catch) { int error; - while (cpipe->pipe_state & PIPE_LOCKFL) { cpipe->pipe_state |= PIPE_LWANT; - error = msleep(cpipe, PIPE_MTX(cpipe), catch ? (PRIBIO | PCATCH) : PRIBIO, "pipelk", 0); if (error != 0) return (error); } cpipe->pipe_state |= PIPE_LOCKFL; - return (0); } /* * unlock a pipe I/O lock */ -static __inline void -pipeunlock(cpipe) - struct pipe *cpipe; +static inline void +pipeio_unlock(struct pipe *cpipe) { - cpipe->pipe_state &= ~PIPE_LOCKFL; - if (cpipe->pipe_state & PIPE_LWANT) { cpipe->pipe_state &= ~PIPE_LWANT; wakeup(cpipe); } } +/* + * wakeup anyone whos blocked in select + */ static void -pipeselwakeup(cpipe, spipe) - struct pipe *cpipe; - struct pipe *spipe; +pipeselwakeup(struct pipe *cpipe, struct pipe *spipe) { - if (cpipe->pipe_state & PIPE_SEL) { cpipe->pipe_state &= ~PIPE_SEL; selwakeup(&cpipe->pipe_sel); @@ -538,18 +701,21 @@ pipeselwakeup(cpipe, spipe) postpipeevent(cpipe, EV_RWBYTES); if (spipe && (spipe->pipe_state & PIPE_ASYNC) && spipe->pipe_pgid) { - struct proc *p; - if (spipe->pipe_pgid < 0) gsignal(-spipe->pipe_pgid, SIGIO); - else if ((p = pfind(spipe->pipe_pgid)) != (struct proc *)0) - psignal(p, SIGIO); + else + proc_signal(spipe->pipe_pgid, SIGIO); } } +/* + * Read n bytes from the buffer. Semantics are similar to file read. + * returns: number of bytes read from the buffer + */ /* ARGSUSED */ static int -pipe_read(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cred, __unused int flags, __unused struct proc *p) +pipe_read(struct fileproc *fp, struct uio *uio, __unused int flags, + __unused vfs_context_t ctx) { struct pipe *rpipe = (struct pipe *)fp->f_data; int error; @@ -559,21 +725,27 @@ pipe_read(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cre PIPE_LOCK(rpipe); ++rpipe->pipe_busy; - error = pipelock(rpipe, 1); + error = pipeio_lock(rpipe, 1); if (error) goto unlocked_error; -#ifdef MAC - error = mac_check_pipe_read(active_cred, rpipe); +#if CONFIG_MACF + error = mac_pipe_check_read(kauth_cred_get(), rpipe); if (error) goto locked_error; #endif + while (uio_resid(uio)) { /* * normal pipe buffer receive */ if (rpipe->pipe_buffer.cnt > 0) { + /* + * # bytes to read is min( bytes from read pointer until end of buffer, + * total unread bytes, + * user requested byte count) + */ size = rpipe->pipe_buffer.size - rpipe->pipe_buffer.out; if (size > rpipe->pipe_buffer.cnt) size = rpipe->pipe_buffer.cnt; @@ -581,7 +753,7 @@ pipe_read(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cre if (size > (u_int) uio_resid(uio)) size = (u_int) uio_resid(uio); - PIPE_UNLOCK(rpipe); + PIPE_UNLOCK(rpipe); /* we still hold io lock.*/ error = uiomove( &rpipe->pipe_buffer.buffer[rpipe->pipe_buffer.out], size, uio); @@ -594,7 +766,7 @@ pipe_read(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cre rpipe->pipe_buffer.out = 0; rpipe->pipe_buffer.cnt -= size; - + /* * If there is no more to read in the pipe, reset * its pointers to the beginning. This improves @@ -605,39 +777,14 @@ pipe_read(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cre rpipe->pipe_buffer.out = 0; } nread += size; -#ifndef PIPE_NODIRECT - /* - * Direct copy, bypassing a kernel buffer. - */ - } else if ((size = rpipe->pipe_map.cnt) && - (rpipe->pipe_state & PIPE_DIRECTW)) { - caddr_t va; - // LP64todo - fix this! - if (size > (u_int) uio_resid(uio)) - size = (u_int) uio_resid(uio); - - va = (caddr_t) rpipe->pipe_map.kva + - rpipe->pipe_map.pos; - PIPE_UNLOCK(rpipe); - error = uiomove(va, size, uio); - PIPE_LOCK(rpipe); - if (error) - break; - nread += size; - rpipe->pipe_map.pos += size; - rpipe->pipe_map.cnt -= size; - if (rpipe->pipe_map.cnt == 0) { - rpipe->pipe_state &= ~PIPE_DIRECTW; - wakeup(rpipe); - } -#endif } else { /* * detect EOF condition * read returns 0 on EOF, no need to set error */ - if (rpipe->pipe_state & PIPE_EOF) + if (rpipe->pipe_state & (PIPE_DRAIN | PIPE_EOF)) { break; + } /* * If the "write-side" has been blocked, wake it up now. @@ -648,7 +795,7 @@ pipe_read(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cre } /* - * Break if some data was read. + * Break if some data was read in previous iteration. */ if (nread > 0) break; @@ -658,7 +805,7 @@ pipe_read(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cre * We will either break out with an error or we will * sleep and relock to loop. */ - pipeunlock(rpipe); + pipeio_unlock(rpipe); /* * Handle non-blocking mode operation or @@ -668,20 +815,18 @@ pipe_read(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cre error = EAGAIN; } else { rpipe->pipe_state |= PIPE_WANTR; - error = msleep(rpipe, PIPE_MTX(rpipe), PRIBIO | PCATCH, "piperd", 0); - if (error == 0) - error = pipelock(rpipe, 1); + error = pipeio_lock(rpipe, 1); } if (error) goto unlocked_error; } } -#ifdef MAC +#if CONFIG_MACF locked_error: #endif - pipeunlock(rpipe); + pipeio_unlock(rpipe); unlocked_error: --rpipe->pipe_busy; @@ -692,7 +837,7 @@ unlocked_error: if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANT)) { rpipe->pipe_state &= ~(PIPE_WANT|PIPE_WANTW); wakeup(rpipe); - } else if (rpipe->pipe_buffer.cnt < MINPIPESIZE) { + } else if (rpipe->pipe_buffer.cnt < rpipe->pipe_buffer.size) { /* * Handle write blocking hysteresis. */ @@ -702,265 +847,32 @@ unlocked_error: } } - if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF) + if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) > 0) pipeselwakeup(rpipe, rpipe->pipe_peer); + /* update last read time */ + pipe_touch(rpipe, PIPE_ATIME); + PIPE_UNLOCK(rpipe); return (error); } - - -#ifndef PIPE_NODIRECT -/* - * Map the sending processes' buffer into kernel space and wire it. - * This is similar to a physical write operation. - */ -static int -pipe_build_write_buffer(wpipe, uio) - struct pipe *wpipe; - struct uio *uio; -{ - pmap_t pmap; - u_int size; - int i, j; - vm_offset_t addr, endaddr; - - - size = (u_int) uio->uio_iov->iov_len; - if (size > wpipe->pipe_buffer.size) - size = wpipe->pipe_buffer.size; - - pmap = vmspace_pmap(curproc->p_vmspace); - endaddr = round_page((vm_offset_t)uio->uio_iov->iov_base + size); - addr = trunc_page((vm_offset_t)uio->uio_iov->iov_base); - for (i = 0; addr < endaddr; addr += PAGE_SIZE, i++) { - /* - * vm_fault_quick() can sleep. Consequently, - * vm_page_lock_queue() and vm_page_unlock_queue() - * should not be performed outside of this loop. - */ - race: - if (vm_fault_quick((caddr_t)addr, VM_PROT_READ) < 0) { - vm_page_lock_queues(); - for (j = 0; j < i; j++) - vm_page_unhold(wpipe->pipe_map.ms[j]); - vm_page_unlock_queues(); - return (EFAULT); - } - wpipe->pipe_map.ms[i] = pmap_extract_and_hold(pmap, addr, - VM_PROT_READ); - if (wpipe->pipe_map.ms[i] == NULL) - goto race; - } - -/* - * set up the control block - */ - wpipe->pipe_map.npages = i; - wpipe->pipe_map.pos = - ((vm_offset_t) uio->uio_iov->iov_base) & PAGE_MASK; - wpipe->pipe_map.cnt = size; - -/* - * and map the buffer - */ - if (wpipe->pipe_map.kva == 0) { - /* - * We need to allocate space for an extra page because the - * address range might (will) span pages at times. - */ - wpipe->pipe_map.kva = kmem_alloc_nofault(kernel_map, - wpipe->pipe_buffer.size + PAGE_SIZE); - atomic_add_int(&amountpipekvawired, - wpipe->pipe_buffer.size + PAGE_SIZE); - } - pmap_qenter(wpipe->pipe_map.kva, wpipe->pipe_map.ms, - wpipe->pipe_map.npages); - -/* - * and update the uio data - */ - - uio->uio_iov->iov_len -= size; - uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + size; - if (uio->uio_iov->iov_len == 0) - uio->uio_iov++; - uio_setresid(uio, (uio_resid(uio) - size)); - uio->uio_offset += size; - return (0); -} - -/* - * unmap and unwire the process buffer - */ -static void -pipe_destroy_write_buffer(wpipe) - struct pipe *wpipe; -{ - int i; - - if (wpipe->pipe_map.kva) { - pmap_qremove(wpipe->pipe_map.kva, wpipe->pipe_map.npages); - - if (amountpipekvawired > maxpipekvawired / 2) { - /* Conserve address space */ - vm_offset_t kva = wpipe->pipe_map.kva; - wpipe->pipe_map.kva = 0; - kmem_free(kernel_map, kva, - wpipe->pipe_buffer.size + PAGE_SIZE); - atomic_subtract_int(&amountpipekvawired, - wpipe->pipe_buffer.size + PAGE_SIZE); - } - } - vm_page_lock_queues(); - for (i = 0; i < wpipe->pipe_map.npages; i++) { - vm_page_unhold(wpipe->pipe_map.ms[i]); - } - vm_page_unlock_queues(); - wpipe->pipe_map.npages = 0; -} - /* - * In the case of a signal, the writing process might go away. This - * code copies the data into the circular buffer so that the source - * pages can be freed without loss of data. - */ -static void -pipe_clone_write_buffer(wpipe) - struct pipe *wpipe; -{ - int size; - int pos; - - size = wpipe->pipe_map.cnt; - pos = wpipe->pipe_map.pos; - - wpipe->pipe_buffer.in = size; - wpipe->pipe_buffer.out = 0; - wpipe->pipe_buffer.cnt = size; - wpipe->pipe_state &= ~PIPE_DIRECTW; - - PIPE_UNLOCK(wpipe); - bcopy((caddr_t) wpipe->pipe_map.kva + pos, - wpipe->pipe_buffer.buffer, size); - pipe_destroy_write_buffer(wpipe); - PIPE_LOCK(wpipe); -} - -/* - * This implements the pipe buffer write mechanism. Note that only - * a direct write OR a normal pipe write can be pending at any given time. - * If there are any characters in the pipe buffer, the direct write will - * be deferred until the receiving process grabs all of the bytes from - * the pipe buffer. Then the direct mapping write is set-up. + * perform a write of n bytes into the read side of buffer. Since + * pipes are unidirectional a write is meant to be read by the otherside only. */ static int -pipe_direct_write(wpipe, uio) - struct pipe *wpipe; - struct uio *uio; -{ - int error; - -retry: - while (wpipe->pipe_state & PIPE_DIRECTW) { - if (wpipe->pipe_state & PIPE_WANTR) { - wpipe->pipe_state &= ~PIPE_WANTR; - wakeup(wpipe); - } - wpipe->pipe_state |= PIPE_WANTW; - error = msleep(wpipe, PIPE_MTX(wpipe), - PRIBIO | PCATCH, "pipdww", 0); - if (error) - goto error1; - if (wpipe->pipe_state & PIPE_EOF) { - error = EPIPE; - goto error1; - } - } - wpipe->pipe_map.cnt = 0; /* transfer not ready yet */ - if (wpipe->pipe_buffer.cnt > 0) { - if (wpipe->pipe_state & PIPE_WANTR) { - wpipe->pipe_state &= ~PIPE_WANTR; - wakeup(wpipe); - } - - wpipe->pipe_state |= PIPE_WANTW; - error = msleep(wpipe, PIPE_MTX(wpipe), - PRIBIO | PCATCH, "pipdwc", 0); - if (error) - goto error1; - if (wpipe->pipe_state & PIPE_EOF) { - error = EPIPE; - goto error1; - } - goto retry; - } - - wpipe->pipe_state |= PIPE_DIRECTW; - - pipelock(wpipe, 0); - PIPE_UNLOCK(wpipe); - error = pipe_build_write_buffer(wpipe, uio); - PIPE_LOCK(wpipe); - pipeunlock(wpipe); - if (error) { - wpipe->pipe_state &= ~PIPE_DIRECTW; - goto error1; - } - - error = 0; - while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) { - if (wpipe->pipe_state & PIPE_EOF) { - pipelock(wpipe, 0); - PIPE_UNLOCK(wpipe); - pipe_destroy_write_buffer(wpipe); - PIPE_LOCK(wpipe); - pipeselwakeup(wpipe, wpipe); - pipeunlock(wpipe); - error = EPIPE; - goto error1; - } - if (wpipe->pipe_state & PIPE_WANTR) { - wpipe->pipe_state &= ~PIPE_WANTR; - wakeup(wpipe); - } - pipeselwakeup(wpipe, wpipe); - error = msleep(wpipe, PIPE_MTX(wpipe), PRIBIO | PCATCH, - "pipdwt", 0); - } - - pipelock(wpipe,0); - if (wpipe->pipe_state & PIPE_DIRECTW) { - /* - * this bit of trickery substitutes a kernel buffer for - * the process that might be going away. - */ - pipe_clone_write_buffer(wpipe); - } else { - PIPE_UNLOCK(wpipe); - pipe_destroy_write_buffer(wpipe); - PIPE_LOCK(wpipe); - } - pipeunlock(wpipe); - return (error); - -error1: - wakeup(wpipe); - return (error); -} -#endif - - - -static int -pipe_write(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cred, __unused int flags, __unused struct proc *p) +pipe_write(struct fileproc *fp, struct uio *uio, __unused int flags, + __unused vfs_context_t ctx) { int error = 0; int orig_resid; int pipe_size; struct pipe *wpipe, *rpipe; + // LP64todo - fix this! + orig_resid = uio_resid(uio); + int space; rpipe = (struct pipe *)fp->f_data; @@ -970,12 +882,12 @@ pipe_write(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cr /* * detect loss of pipe read side, issue SIGPIPE if lost. */ - if (wpipe == NULL || (wpipe->pipe_state & PIPE_EOF)) { + if (wpipe == NULL || (wpipe->pipe_state & (PIPE_DRAIN | PIPE_EOF))) { PIPE_UNLOCK(rpipe); return (EPIPE); } -#ifdef MAC - error = mac_check_pipe_write(active_cred, wpipe); +#if CONFIG_MACF + error = mac_pipe_check_write(kauth_cred_get(), wpipe); if (error) { PIPE_UNLOCK(rpipe); return (error); @@ -985,54 +897,35 @@ pipe_write(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cr pipe_size = 0; - if (wpipe->pipe_buffer.buffer == 0) { - /* - * need to allocate some storage... we delay the allocation - * until the first write on fd[0] to avoid allocating storage for both - * 'pipe ends'... most pipes are half-duplex with the writes targeting - * fd[1], so allocating space for both ends is a waste... - * - * Reduce to 1/4th pipe size if we're over our global max. - */ - if (amountpipekva > maxpipekva / 2) - pipe_size = SMALL_PIPE_SIZE; - else - pipe_size = PIPE_SIZE; - } - /* - * If it is advantageous to resize the pipe buffer, do - * so. + * need to allocate some storage... we delay the allocation + * until the first write on fd[0] to avoid allocating storage for both + * 'pipe ends'... most pipes are half-duplex with the writes targeting + * fd[1], so allocating space for both ends is a waste... */ - if ((uio_resid(uio) > PIPE_SIZE) && - (wpipe->pipe_buffer.size <= PIPE_SIZE) && - (amountpipekva < maxpipekva / 2) && - (nbigpipe < LIMITBIGPIPES) && -#ifndef PIPE_NODIRECT - (wpipe->pipe_state & PIPE_DIRECTW) == 0 && -#endif - (wpipe->pipe_buffer.cnt == 0)) { - pipe_size = BIG_PIPE_SIZE; + if ( wpipe->pipe_buffer.buffer == 0 || ( + (unsigned)orig_resid > wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt && + amountpipekva < maxpipekva ) ) { + pipe_size = choose_pipespace(wpipe->pipe_buffer.size, wpipe->pipe_buffer.cnt + orig_resid); } if (pipe_size) { /* * need to do initial allocation or resizing of pipe + * holding both structure and io locks. */ - if ((error = pipelock(wpipe, 1)) == 0) { - PIPE_UNLOCK(wpipe); - if (pipespace(wpipe, pipe_size) == 0) - OSAddAtomic(1, (SInt32 *)&nbigpipe); - PIPE_LOCK(wpipe); - pipeunlock(wpipe); - - if (wpipe->pipe_buffer.buffer == 0) { - /* - * initial allocation failed - */ + if ((error = pipeio_lock(wpipe, 1)) == 0) { + if (wpipe->pipe_buffer.cnt == 0) + error = pipespace(wpipe, pipe_size); + else + error = expand_pipespace(wpipe, pipe_size); + + pipeio_unlock(wpipe); + + /* allocation failed */ + if (wpipe->pipe_buffer.buffer == 0) error = ENOMEM; - } } if (error) { /* @@ -1049,91 +942,35 @@ pipe_write(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cr return(error); } } - // LP64todo - fix this! - orig_resid = uio_resid(uio); while (uio_resid(uio)) { - int space; - -#ifndef PIPE_NODIRECT - /* - * If the transfer is large, we can gain performance if - * we do process-to-process copies directly. - * If the write is non-blocking, we don't use the - * direct write mechanism. - * - * The direct write mechanism will detect the reader going - * away on us. - */ - if ((uio->uio_iov->iov_len >= PIPE_MINDIRECT) && - (fp->f_flag & FNONBLOCK) == 0 && - amountpipekvawired + uio->uio_resid < maxpipekvawired) { - error = pipe_direct_write(wpipe, uio); - if (error) - break; - continue; - } - /* - * Pipe buffered writes cannot be coincidental with - * direct writes. We wait until the currently executing - * direct write is completed before we start filling the - * pipe buffer. We break out if a signal occurs or the - * reader goes away. - */ - retrywrite: - while (wpipe->pipe_state & PIPE_DIRECTW) { - if (wpipe->pipe_state & PIPE_WANTR) { - wpipe->pipe_state &= ~PIPE_WANTR; - wakeup(wpipe); - } - error = msleep(wpipe, PIPE_MTX(wpipe), PRIBIO | PCATCH, "pipbww", 0); - - if (wpipe->pipe_state & PIPE_EOF) - break; - if (error) - break; - } -#else retrywrite: -#endif space = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; - /* - * Writes of size <= PIPE_BUF must be atomic. - */ + /* Writes of size <= PIPE_BUF must be atomic. */ if ((space < uio_resid(uio)) && (orig_resid <= PIPE_BUF)) space = 0; if (space > 0) { - if ((error = pipelock(wpipe,1)) == 0) { + if ((error = pipeio_lock(wpipe,1)) == 0) { int size; /* Transfer size */ int segsize; /* first segment to transfer */ - if (wpipe->pipe_state & PIPE_EOF) { - pipeunlock(wpipe); + if (wpipe->pipe_state & (PIPE_DRAIN | PIPE_EOF)) { + pipeio_unlock(wpipe); error = EPIPE; break; } -#ifndef PIPE_NODIRECT - /* - * It is possible for a direct write to - * slip in on us... handle it here... - */ - if (wpipe->pipe_state & PIPE_DIRECTW) { - pipeunlock(wpipe); - goto retrywrite; - } -#endif /* - * If a process blocked in pipelock, our + * If a process blocked in pipeio_lock, our * value for space might be bad... the mutex * is dropped while we're blocked */ if (space > (int)(wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt)) { - pipeunlock(wpipe); + pipeio_unlock(wpipe); goto retrywrite; } @@ -1169,7 +1006,7 @@ pipe_write(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cr /* * Transfer remaining part now, to * support atomic writes. Wraparound - * happened. + * happened. (State 3) */ if (wpipe->pipe_buffer.in + segsize != wpipe->pipe_buffer.size) @@ -1182,9 +1019,12 @@ pipe_write(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cr size - segsize, uio); PIPE_LOCK(rpipe); } + /* + * readers never know to read until count is updated. + */ if (error == 0) { wpipe->pipe_buffer.in += size; - if (wpipe->pipe_buffer.in >= + if (wpipe->pipe_buffer.in > wpipe->pipe_buffer.size) { if (wpipe->pipe_buffer.in != size - segsize + @@ -1201,7 +1041,7 @@ pipe_write(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cr panic("Pipe buffer overflow"); } - pipeunlock(wpipe); + pipeio_unlock(wpipe); } if (error) break; @@ -1222,6 +1062,16 @@ pipe_write(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cr error = EAGAIN; break; } + + /* + * If read side wants to go away, we just issue a signal + * to ourselves. + */ + if (wpipe->pipe_state & (PIPE_DRAIN | PIPE_EOF)) { + error = EPIPE; + break; + } + /* * We have no more space and have something to offer, * wake up select/poll. @@ -1234,14 +1084,6 @@ pipe_write(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cr if (error != 0) break; - /* - * If read side wants to go away, we just issue a signal - * to ourselves. - */ - if (wpipe->pipe_state & PIPE_EOF) { - error = EPIPE; - break; - } } } --wpipe->pipe_busy; @@ -1264,6 +1106,10 @@ pipe_write(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cr */ pipeselwakeup(wpipe, wpipe); } + + /* Update modification, status change (# of bytes in pipe) times */ + pipe_touch(rpipe, PIPE_MTIME | PIPE_CTIME); + pipe_touch(wpipe, PIPE_MTIME | PIPE_CTIME); PIPE_UNLOCK(rpipe); return (error); @@ -1274,17 +1120,18 @@ pipe_write(struct fileproc *fp, struct uio *uio, __unused kauth_cred_t active_cr */ /* ARGSUSED 3 */ static int -pipe_ioctl(struct fileproc *fp, u_long cmd, caddr_t data, __unused struct proc *p) +pipe_ioctl(struct fileproc *fp, u_long cmd, caddr_t data, + __unused vfs_context_t ctx) { struct pipe *mpipe = (struct pipe *)fp->f_data; -#ifdef MAC +#if CONFIG_MACF int error; #endif PIPE_LOCK(mpipe); -#ifdef MAC - error = mac_check_pipe_ioctl(active_cred, mpipe, cmd, data); +#if CONFIG_MACF + error = mac_pipe_check_ioctl(kauth_cred_get(), mpipe, cmd); if (error) { PIPE_UNLOCK(mpipe); @@ -1308,12 +1155,7 @@ pipe_ioctl(struct fileproc *fp, u_long cmd, caddr_t data, __unused struct proc * return (0); case FIONREAD: -#ifndef PIPE_NODIRECT - if (mpipe->pipe_state & PIPE_DIRECTW) - *(int *)data = mpipe->pipe_map.cnt; - else -#endif - *(int *)data = mpipe->pipe_buffer.cnt; + *(int *)data = mpipe->pipe_buffer.cnt; PIPE_UNLOCK(mpipe); return (0); @@ -1336,7 +1178,7 @@ pipe_ioctl(struct fileproc *fp, u_long cmd, caddr_t data, __unused struct proc * static int -pipe_select(struct fileproc *fp, int which, void *wql, struct proc *p) +pipe_select(struct fileproc *fp, int which, void *wql, vfs_context_t ctx) { struct pipe *rpipe = (struct pipe *)fp->f_data; struct pipe *wpipe; @@ -1348,35 +1190,49 @@ pipe_select(struct fileproc *fp, int which, void *wql, struct proc *p) PIPE_LOCK(rpipe); wpipe = rpipe->pipe_peer; + +#if CONFIG_MACF + /* + * XXX We should use a per thread credential here; minimally, the + * XXX process credential should have a persistent reference on it + * XXX before being passed in here. + */ + if (mac_pipe_check_select(vfs_context_ucred(ctx), rpipe, which)) { + PIPE_UNLOCK(rpipe); + return (0); + } +#endif switch (which) { case FREAD: if ((rpipe->pipe_state & PIPE_DIRECTW) || (rpipe->pipe_buffer.cnt > 0) || - (rpipe->pipe_state & PIPE_EOF)) { + (rpipe->pipe_state & (PIPE_DRAIN | PIPE_EOF))) { retnum = 1; } else { rpipe->pipe_state |= PIPE_SEL; - selrecord(p, &rpipe->pipe_sel, wql); + selrecord(vfs_context_proc(ctx), &rpipe->pipe_sel, wql); } break; case FWRITE: - if (wpipe == NULL || (wpipe->pipe_state & PIPE_EOF) || + if (wpipe) + wpipe->pipe_state |= PIPE_WSELECT; + if (wpipe == NULL || (wpipe->pipe_state & (PIPE_DRAIN | PIPE_EOF)) || (((wpipe->pipe_state & PIPE_DIRECTW) == 0) && - (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF)) { + (MAX_PIPESIZE(wpipe) - wpipe->pipe_buffer.cnt) >= PIPE_BUF)) { retnum = 1; } else { wpipe->pipe_state |= PIPE_SEL; - selrecord(p, &wpipe->pipe_sel, wql); + selrecord(vfs_context_proc(ctx), &wpipe->pipe_sel, wql); } break; case 0: rpipe->pipe_state |= PIPE_SEL; - selrecord(p, &rpipe->pipe_sel, wql); + selrecord(vfs_context_proc(ctx), &rpipe->pipe_sel, wql); break; } PIPE_UNLOCK(rpipe); @@ -1387,15 +1243,14 @@ pipe_select(struct fileproc *fp, int which, void *wql, struct proc *p) /* ARGSUSED 1 */ static int -pipe_close(struct fileglob *fg, __unused struct proc *p) +pipe_close(struct fileglob *fg, __unused vfs_context_t ctx) { struct pipe *cpipe; - proc_fdlock(p); + proc_fdlock_spin(vfs_context_proc(ctx)); cpipe = (struct pipe *)fg->fg_data; fg->fg_data = NULL; - proc_fdunlock(p); - + proc_fdunlock(vfs_context_proc(ctx)); if (cpipe) pipeclose(cpipe); @@ -1405,30 +1260,14 @@ pipe_close(struct fileglob *fg, __unused struct proc *p) static void pipe_free_kmem(struct pipe *cpipe) { - if (cpipe->pipe_buffer.buffer != NULL) { - if (cpipe->pipe_buffer.size > PIPE_SIZE) - OSAddAtomic(-1, (SInt32 *)&nbigpipe); - OSAddAtomic(-(cpipe->pipe_buffer.size), (SInt32 *)&amountpipekva); - OSAddAtomic(-1, (SInt32 *)&amountpipes); - - kmem_free(kernel_map, (vm_offset_t)cpipe->pipe_buffer.buffer, + OSAddAtomic(-(cpipe->pipe_buffer.size), &amountpipekva); + OSAddAtomic(-1, &amountpipes); + kfree((void *)cpipe->pipe_buffer.buffer, cpipe->pipe_buffer.size); cpipe->pipe_buffer.buffer = NULL; + cpipe->pipe_buffer.size = 0; } -#ifndef PIPE_NODIRECT - if (cpipe->pipe_map.kva != 0) { - atomic_subtract_int(&amountpipekvawired, - cpipe->pipe_buffer.size + PAGE_SIZE); - kmem_free(kernel_map, - cpipe->pipe_map.kva, - cpipe->pipe_buffer.size + PAGE_SIZE); - cpipe->pipe_map.cnt = 0; - cpipe->pipe_map.kva = 0; - cpipe->pipe_map.pos = 0; - cpipe->pipe_map.npages = 0; - } -#endif } /* @@ -1441,28 +1280,32 @@ pipeclose(struct pipe *cpipe) if (cpipe == NULL) return; - /* partially created pipes won't have a valid mutex. */ if (PIPE_MTX(cpipe) != NULL) PIPE_LOCK(cpipe); - pipeselwakeup(cpipe, cpipe); /* * If the other side is blocked, wake it up saying that * we want to close it down. */ + cpipe->pipe_state &= ~PIPE_DRAIN; + cpipe->pipe_state |= PIPE_EOF; + pipeselwakeup(cpipe, cpipe); + while (cpipe->pipe_busy) { - cpipe->pipe_state |= PIPE_WANT | PIPE_EOF; + cpipe->pipe_state |= PIPE_WANT; wakeup(cpipe); - msleep(cpipe, PIPE_MTX(cpipe), PRIBIO, "pipecl", 0); } -#ifdef MAC +#if CONFIG_MACF + /* + * Free the shared pipe label only after the two ends are disconnected. + */ if (cpipe->pipe_label != NULL && cpipe->pipe_peer == NULL) - mac_destroy_pipe(cpipe); + mac_pipe_label_destroy(cpipe); #endif /* @@ -1470,6 +1313,7 @@ pipeclose(struct pipe *cpipe) */ if ((ppipe = cpipe->pipe_peer) != NULL) { + ppipe->pipe_state &= ~(PIPE_DRAIN); ppipe->pipe_state |= PIPE_EOF; pipeselwakeup(ppipe, ppipe); @@ -1488,39 +1332,56 @@ pipeclose(struct pipe *cpipe) * free resources */ if (PIPE_MTX(cpipe) != NULL) { - if (ppipe != NULL) { - /* + if (ppipe != NULL) { + /* * since the mutex is shared and the peer is still * alive, we need to release the mutex, not free it */ - PIPE_UNLOCK(cpipe); + PIPE_UNLOCK(cpipe); } else { - /* + /* * peer is gone, so we're the sole party left with - * interest in this mutex... we can just free it + * interest in this mutex... unlock and free it */ + PIPE_UNLOCK(cpipe); lck_mtx_free(PIPE_MTX(cpipe), pipe_mtx_grp); } } pipe_free_kmem(cpipe); + if (cpipe->pipe_state & PIPE_WSELECT) { + pipe_garbage_collect(cpipe); + } else { + zfree(pipe_zone, cpipe); + pipe_garbage_collect(NULL); + } - zfree(pipe_zone, cpipe); } - /*ARGSUSED*/ static int -pipe_kqfilter(__unused struct fileproc *fp, struct knote *kn, __unused struct proc *p) +pipe_kqfilter(__unused struct fileproc *fp, struct knote *kn, __unused vfs_context_t ctx) { struct pipe *cpipe; cpipe = (struct pipe *)kn->kn_fp->f_data; PIPE_LOCK(cpipe); +#if CONFIG_MACF + /* + * XXX We should use a per thread credential here; minimally, the + * XXX process credential should have a persistent reference on it + * XXX before being passed in here. + */ + if (mac_pipe_check_kqfilter(vfs_context_ucred(ctx), kn, cpipe) != 0) { + PIPE_UNLOCK(cpipe); + return (1); + } +#endif switch (kn->kn_filter) { case EVFILT_READ: kn->kn_fop = &pipe_rfiltops; + break; case EVFILT_WRITE: kn->kn_fop = &pipe_wfiltops; @@ -1532,6 +1393,7 @@ pipe_kqfilter(__unused struct fileproc *fp, struct knote *kn, __unused struct pr PIPE_UNLOCK(cpipe); return (EPIPE); } + if (cpipe->pipe_peer) cpipe = cpipe->pipe_peer; break; default: @@ -1586,18 +1448,20 @@ filt_piperead(struct knote *kn, long hint) wpipe = rpipe->pipe_peer; kn->kn_data = rpipe->pipe_buffer.cnt; - -#ifndef PIPE_NODIRECT - if ((kn->kn_data == 0) && (rpipe->pipe_state & PIPE_DIRECTW)) - kn->kn_data = rpipe->pipe_map.cnt; -#endif - if ((rpipe->pipe_state & PIPE_EOF) || - (wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { + if ((rpipe->pipe_state & (PIPE_DRAIN | PIPE_EOF)) || + (wpipe == NULL) || (wpipe->pipe_state & (PIPE_DRAIN | PIPE_EOF))) { kn->kn_flags |= EV_EOF; retval = 1; - } else - retval = (kn->kn_sfflags & NOTE_LOWAT) ? - (kn->kn_data >= kn->kn_sdata) : (kn->kn_data > 0); + } else { + int64_t lowwat = 1; + if (kn->kn_sfflags & NOTE_LOWAT) { + if (rpipe->pipe_buffer.size && kn->kn_sdata > MAX_PIPESIZE(rpipe)) + lowwat = MAX_PIPESIZE(rpipe); + else if (kn->kn_sdata > lowwat) + lowwat = kn->kn_sdata; + } + retval = kn->kn_data >= lowwat; + } if (hint == 0) PIPE_UNLOCK(rpipe); @@ -1623,7 +1487,7 @@ filt_pipewrite(struct knote *kn, long hint) wpipe = rpipe->pipe_peer; - if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { + if ((wpipe == NULL) || (wpipe->pipe_state & (PIPE_DRAIN | PIPE_EOF))) { kn->kn_data = 0; kn->kn_flags |= EV_EOF; @@ -1631,78 +1495,203 @@ filt_pipewrite(struct knote *kn, long hint) PIPE_UNLOCK(rpipe); return (1); } - kn->kn_data = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; - -#ifndef PIPE_NODIRECT - if (wpipe->pipe_state & PIPE_DIRECTW) - kn->kn_data = 0; -#endif + kn->kn_data = MAX_PIPESIZE(wpipe) - wpipe->pipe_buffer.cnt; + + int64_t lowwat = PIPE_BUF; + if (kn->kn_sfflags & NOTE_LOWAT) { + if (wpipe->pipe_buffer.size && kn->kn_sdata > MAX_PIPESIZE(wpipe)) + lowwat = MAX_PIPESIZE(wpipe); + else if (kn->kn_sdata > lowwat) + lowwat = kn->kn_sdata; + } + if (hint == 0) PIPE_UNLOCK(rpipe); - return (kn->kn_data >= ((kn->kn_sfflags & NOTE_LOWAT) ? - kn->kn_sdata : PIPE_BUF)); + return (kn->kn_data >= lowwat); } int fill_pipeinfo(struct pipe * cpipe, struct pipe_info * pinfo) { -#ifdef MAC +#if CONFIG_MACF int error; #endif struct timeval now; - struct stat * ub; + struct vinfo_stat * ub; + int pipe_size = 0; + int pipe_count; if (cpipe == NULL) return (EBADF); -#ifdef MAC PIPE_LOCK(cpipe); - error = mac_check_pipe_stat(active_cred, cpipe); - PIPE_UNLOCK(cpipe); - if (error) + +#if CONFIG_MACF + error = mac_pipe_check_stat(kauth_cred_get(), cpipe); + if (error) { + PIPE_UNLOCK(cpipe); return (error); + } #endif if (cpipe->pipe_buffer.buffer == 0) { /* * must be stat'ing the write fd */ - cpipe = cpipe->pipe_peer; - - if (cpipe == NULL) - return (EBADF); + if (cpipe->pipe_peer) { + /* + * the peer still exists, use it's info + */ + pipe_size = MAX_PIPESIZE(cpipe->pipe_peer); + pipe_count = cpipe->pipe_peer->pipe_buffer.cnt; + } else { + pipe_count = 0; + } + } else { + pipe_size = MAX_PIPESIZE(cpipe); + pipe_count = cpipe->pipe_buffer.cnt; } + /* + * since peer's buffer is setup ouside of lock + * we might catch it in transient state + */ + if (pipe_size == 0) + pipe_size = PIPE_SIZE; ub = &pinfo->pipe_stat; bzero(ub, sizeof(*ub)); - ub->st_mode = S_IFIFO | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP; - ub->st_blksize = cpipe->pipe_buffer.size; - ub->st_size = cpipe->pipe_buffer.cnt; - if (ub->st_blksize != 0); - ub->st_blocks = (ub->st_size + ub->st_blksize - 1) / ub->st_blksize; - ub->st_nlink = 1; + ub->vst_mode = S_IFIFO | S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP; + ub->vst_blksize = pipe_size; + ub->vst_size = pipe_count; + if (ub->vst_blksize != 0) + ub->vst_blocks = (ub->vst_size + ub->vst_blksize - 1) / ub->vst_blksize; + ub->vst_nlink = 1; - ub->st_uid = kauth_getuid(); - ub->st_gid = kauth_getgid(); + ub->vst_uid = kauth_getuid(); + ub->vst_gid = kauth_getgid(); microtime(&now); - ub->st_atimespec.tv_sec = now.tv_sec; - ub->st_atimespec.tv_nsec = now.tv_usec * 1000; + ub->vst_atime = now.tv_sec; + ub->vst_atimensec = now.tv_usec * 1000; - ub->st_mtimespec.tv_sec = now.tv_sec; - ub->st_mtimespec.tv_nsec = now.tv_usec * 1000; + ub->vst_mtime = now.tv_sec; + ub->vst_mtimensec = now.tv_usec * 1000; - ub->st_ctimespec.tv_sec = now.tv_sec; - ub->st_ctimespec.tv_nsec = now.tv_usec * 1000; + ub->vst_ctime = now.tv_sec; + ub->vst_ctimensec = now.tv_usec * 1000; /* * Left as 0: st_dev, st_ino, st_nlink, st_rdev, st_flags, st_gen, st_uid, st_gid. * XXX (st_dev, st_ino) should be unique. */ - pinfo->pipe_handle = (uint64_t)((uintptr_t)cpipe); - pinfo->pipe_peerhandle = (uint64_t)((uintptr_t)(cpipe->pipe_peer)); + pinfo->pipe_handle = (uint64_t)VM_KERNEL_ADDRPERM((uintptr_t)cpipe); + pinfo->pipe_peerhandle = (uint64_t)VM_KERNEL_ADDRPERM((uintptr_t)(cpipe->pipe_peer)); pinfo->pipe_status = cpipe->pipe_state; + + PIPE_UNLOCK(cpipe); + return (0); } + +static int +pipe_drain(struct fileproc *fp, __unused vfs_context_t ctx) +{ + + /* Note: fdlock already held */ + struct pipe *ppipe, *cpipe = (struct pipe *)(fp->f_fglob->fg_data); + + if (cpipe) { + PIPE_LOCK(cpipe); + cpipe->pipe_state |= PIPE_DRAIN; + cpipe->pipe_state &= ~(PIPE_WANTR | PIPE_WANTW); + wakeup(cpipe); + + /* Must wake up peer: a writer sleeps on the read side */ + if ((ppipe = cpipe->pipe_peer)) { + ppipe->pipe_state |= PIPE_DRAIN; + ppipe->pipe_state &= ~(PIPE_WANTR | PIPE_WANTW); + wakeup(ppipe); + } + + PIPE_UNLOCK(cpipe); + return 0; + } + + return 1; +} + + + /* + * When a thread sets a write-select on a pipe, it creates an implicit, + * untracked dependency between that thread and the peer of the pipe + * on which the select is set. If the peer pipe is closed and freed + * before the select()ing thread wakes up, the system will panic as + * it attempts to unwind the dangling select(). To avoid that panic, + * we notice whenever a dangerous select() is set on a pipe, and + * defer the final deletion of the pipe until that select()s are all + * resolved. Since we can't currently detect exactly when that + * resolution happens, we use a simple garbage collection queue to + * reap the at-risk pipes 'later'. + */ +static void +pipe_garbage_collect(struct pipe *cpipe) +{ + uint64_t old, now; + struct pipe_garbage *pgp; + + /* Convert msecs to nsecs and then to abstime */ + old = pipe_garbage_age_limit * 1000000; + nanoseconds_to_absolutetime(old, &old); + + lck_mtx_lock(pipe_garbage_lock); + + /* Free anything that's been on the queue for seconds */ + now = mach_absolute_time(); + old = now - old; + while ((pgp = pipe_garbage_head) && pgp->pg_timestamp < old) { + pipe_garbage_head = pgp->pg_next; + if (pipe_garbage_head == NULL) + pipe_garbage_tail = NULL; + pipe_garbage_count--; + zfree(pipe_zone, pgp->pg_pipe); + zfree(pipe_garbage_zone, pgp); + } + + /* Add the new pipe (if any) to the tail of the garbage queue */ + if (cpipe) { + cpipe->pipe_state = PIPE_DEAD; + pgp = (struct pipe_garbage *)zalloc(pipe_garbage_zone); + if (pgp == NULL) { + /* + * We're too low on memory to garbage collect the + * pipe. Freeing it runs the risk of panicing the + * system. All we can do is leak it and leave + * a breadcrumb behind. The good news, such as it + * is, is that this will probably never happen. + * We will probably hit the panic below first. + */ + printf("Leaking pipe %p - no room left in the queue", + cpipe); + lck_mtx_unlock(pipe_garbage_lock); + return; + } + + pgp->pg_pipe = cpipe; + pgp->pg_timestamp = now; + pgp->pg_next = NULL; + + if (pipe_garbage_tail) + pipe_garbage_tail->pg_next = pgp; + pipe_garbage_tail = pgp; + if (pipe_garbage_head == NULL) + pipe_garbage_head = pipe_garbage_tail; + + if (pipe_garbage_count++ >= PIPE_GARBAGE_QUEUE_LIMIT) + panic("Length of pipe garbage queue exceeded %d", + PIPE_GARBAGE_QUEUE_LIMIT); + } + lck_mtx_unlock(pipe_garbage_lock); +} +