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sys_pipe.c revision 1.71.2.2
      1  1.71.2.2      yamt /*	$NetBSD: sys_pipe.c,v 1.71.2.2 2006/06/26 12:52:57 yamt Exp $	*/
      2      1.35        pk 
      3      1.35        pk /*-
      4      1.35        pk  * Copyright (c) 2003 The NetBSD Foundation, Inc.
      5      1.35        pk  * All rights reserved.
      6      1.35        pk  *
      7      1.35        pk  * This code is derived from software contributed to The NetBSD Foundation
      8      1.35        pk  * by Paul Kranenburg.
      9      1.35        pk  *
     10      1.35        pk  * Redistribution and use in source and binary forms, with or without
     11      1.35        pk  * modification, are permitted provided that the following conditions
     12      1.35        pk  * are met:
     13      1.35        pk  * 1. Redistributions of source code must retain the above copyright
     14      1.35        pk  *    notice, this list of conditions and the following disclaimer.
     15      1.35        pk  * 2. Redistributions in binary form must reproduce the above copyright
     16      1.35        pk  *    notice, this list of conditions and the following disclaimer in the
     17      1.35        pk  *    documentation and/or other materials provided with the distribution.
     18      1.35        pk  * 3. All advertising materials mentioning features or use of this software
     19      1.35        pk  *    must display the following acknowledgement:
     20      1.35        pk  *        This product includes software developed by the NetBSD
     21      1.35        pk  *        Foundation, Inc. and its contributors.
     22      1.35        pk  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23      1.35        pk  *    contributors may be used to endorse or promote products derived
     24      1.35        pk  *    from this software without specific prior written permission.
     25      1.35        pk  *
     26      1.35        pk  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27      1.35        pk  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28      1.35        pk  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29      1.35        pk  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30      1.35        pk  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31      1.35        pk  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32      1.35        pk  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33      1.35        pk  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34      1.35        pk  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35      1.35        pk  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36      1.35        pk  * POSSIBILITY OF SUCH DAMAGE.
     37      1.35        pk  */
     38       1.2  jdolecek 
     39       1.1  jdolecek /*
     40       1.1  jdolecek  * Copyright (c) 1996 John S. Dyson
     41       1.1  jdolecek  * All rights reserved.
     42       1.1  jdolecek  *
     43       1.1  jdolecek  * Redistribution and use in source and binary forms, with or without
     44       1.1  jdolecek  * modification, are permitted provided that the following conditions
     45       1.1  jdolecek  * are met:
     46       1.1  jdolecek  * 1. Redistributions of source code must retain the above copyright
     47       1.1  jdolecek  *    notice immediately at the beginning of the file, without modification,
     48       1.1  jdolecek  *    this list of conditions, and the following disclaimer.
     49       1.1  jdolecek  * 2. Redistributions in binary form must reproduce the above copyright
     50       1.1  jdolecek  *    notice, this list of conditions and the following disclaimer in the
     51       1.1  jdolecek  *    documentation and/or other materials provided with the distribution.
     52       1.1  jdolecek  * 3. Absolutely no warranty of function or purpose is made by the author
     53       1.1  jdolecek  *    John S. Dyson.
     54       1.1  jdolecek  * 4. Modifications may be freely made to this file if the above conditions
     55       1.1  jdolecek  *    are met.
     56       1.1  jdolecek  *
     57      1.24  jdolecek  * $FreeBSD: src/sys/kern/sys_pipe.c,v 1.95 2002/03/09 22:06:31 alfred Exp $
     58       1.1  jdolecek  */
     59       1.1  jdolecek 
     60       1.1  jdolecek /*
     61       1.1  jdolecek  * This file contains a high-performance replacement for the socket-based
     62       1.1  jdolecek  * pipes scheme originally used in FreeBSD/4.4Lite.  It does not support
     63       1.1  jdolecek  * all features of sockets, but does do everything that pipes normally
     64       1.1  jdolecek  * do.
     65       1.2  jdolecek  *
     66       1.2  jdolecek  * Adaption for NetBSD UVM, including uvm_loan() based direct write, was
     67       1.2  jdolecek  * written by Jaromir Dolecek.
     68       1.1  jdolecek  */
     69       1.1  jdolecek 
     70       1.1  jdolecek /*
     71       1.1  jdolecek  * This code has two modes of operation, a small write mode and a large
     72       1.1  jdolecek  * write mode.  The small write mode acts like conventional pipes with
     73       1.1  jdolecek  * a kernel buffer.  If the buffer is less than PIPE_MINDIRECT, then the
     74       1.1  jdolecek  * "normal" pipe buffering is done.  If the buffer is between PIPE_MINDIRECT
     75      1.35        pk  * and PIPE_SIZE in size it is mapped read-only into the kernel address space
     76      1.35        pk  * using the UVM page loan facility from where the receiving process can copy
     77      1.35        pk  * the data directly from the pages in the sending process.
     78       1.1  jdolecek  *
     79       1.1  jdolecek  * The constant PIPE_MINDIRECT is chosen to make sure that buffering will
     80       1.1  jdolecek  * happen for small transfers so that the system will not spend all of
     81       1.1  jdolecek  * its time context switching.  PIPE_SIZE is constrained by the
     82       1.1  jdolecek  * amount of kernel virtual memory.
     83       1.1  jdolecek  */
     84      1.19     lukem 
     85      1.19     lukem #include <sys/cdefs.h>
     86  1.71.2.2      yamt __KERNEL_RCSID(0, "$NetBSD: sys_pipe.c,v 1.71.2.2 2006/06/26 12:52:57 yamt Exp $");
     87       1.2  jdolecek 
     88       1.1  jdolecek #include <sys/param.h>
     89       1.1  jdolecek #include <sys/systm.h>
     90       1.2  jdolecek #include <sys/proc.h>
     91       1.1  jdolecek #include <sys/fcntl.h>
     92       1.1  jdolecek #include <sys/file.h>
     93       1.1  jdolecek #include <sys/filedesc.h>
     94       1.1  jdolecek #include <sys/filio.h>
     95      1.24  jdolecek #include <sys/kernel.h>
     96      1.24  jdolecek #include <sys/lock.h>
     97       1.1  jdolecek #include <sys/ttycom.h>
     98       1.1  jdolecek #include <sys/stat.h>
     99      1.24  jdolecek #include <sys/malloc.h>
    100       1.1  jdolecek #include <sys/poll.h>
    101       1.2  jdolecek #include <sys/signalvar.h>
    102       1.2  jdolecek #include <sys/vnode.h>
    103       1.2  jdolecek #include <sys/uio.h>
    104       1.2  jdolecek #include <sys/lock.h>
    105       1.2  jdolecek #include <sys/select.h>
    106       1.2  jdolecek #include <sys/mount.h>
    107      1.33   thorpej #include <sys/sa.h>
    108       1.2  jdolecek #include <sys/syscallargs.h>
    109       1.2  jdolecek #include <uvm/uvm.h>
    110       1.2  jdolecek #include <sys/sysctl.h>
    111      1.17  jdolecek #include <sys/kernel.h>
    112  1.71.2.1      yamt #include <sys/kauth.h>
    113       1.2  jdolecek 
    114       1.1  jdolecek #include <sys/pipe.h>
    115       1.1  jdolecek 
    116      1.17  jdolecek /*
    117       1.1  jdolecek  * Use this define if you want to disable *fancy* VM things.  Expect an
    118      1.35        pk  * approx 30% decrease in transfer rate.
    119       1.1  jdolecek  */
    120       1.1  jdolecek /* #define PIPE_NODIRECT */
    121       1.1  jdolecek 
    122       1.1  jdolecek /*
    123       1.1  jdolecek  * interfaces to the outside world
    124       1.1  jdolecek  */
    125      1.63     perry static int pipe_read(struct file *fp, off_t *offset, struct uio *uio,
    126  1.71.2.1      yamt 		kauth_cred_t cred, int flags);
    127      1.63     perry static int pipe_write(struct file *fp, off_t *offset, struct uio *uio,
    128  1.71.2.1      yamt 		kauth_cred_t cred, int flags);
    129      1.69  christos static int pipe_close(struct file *fp, struct lwp *l);
    130      1.69  christos static int pipe_poll(struct file *fp, int events, struct lwp *l);
    131      1.27  jdolecek static int pipe_kqfilter(struct file *fp, struct knote *kn);
    132      1.69  christos static int pipe_stat(struct file *fp, struct stat *sb, struct lwp *l);
    133      1.38       dsl static int pipe_ioctl(struct file *fp, u_long cmd, void *data,
    134      1.69  christos 		struct lwp *l);
    135       1.1  jdolecek 
    136      1.62  christos static const struct fileops pipeops = {
    137      1.62  christos 	pipe_read, pipe_write, pipe_ioctl, fnullop_fcntl, pipe_poll,
    138      1.35        pk 	pipe_stat, pipe_close, pipe_kqfilter
    139      1.35        pk };
    140       1.1  jdolecek 
    141       1.1  jdolecek /*
    142       1.1  jdolecek  * Default pipe buffer size(s), this can be kind-of large now because pipe
    143       1.1  jdolecek  * space is pageable.  The pipe code will try to maintain locality of
    144       1.1  jdolecek  * reference for performance reasons, so small amounts of outstanding I/O
    145       1.1  jdolecek  * will not wipe the cache.
    146       1.1  jdolecek  */
    147       1.1  jdolecek #define MINPIPESIZE (PIPE_SIZE/3)
    148       1.1  jdolecek #define MAXPIPESIZE (2*PIPE_SIZE/3)
    149       1.1  jdolecek 
    150       1.1  jdolecek /*
    151       1.1  jdolecek  * Maximum amount of kva for pipes -- this is kind-of a soft limit, but
    152       1.1  jdolecek  * is there so that on large systems, we don't exhaust it.
    153       1.1  jdolecek  */
    154       1.1  jdolecek #define MAXPIPEKVA (8*1024*1024)
    155       1.2  jdolecek static int maxpipekva = MAXPIPEKVA;
    156       1.1  jdolecek 
    157       1.1  jdolecek /*
    158       1.1  jdolecek  * Limit for direct transfers, we cannot, of course limit
    159       1.1  jdolecek  * the amount of kva for pipes in general though.
    160       1.1  jdolecek  */
    161       1.1  jdolecek #define LIMITPIPEKVA (16*1024*1024)
    162       1.2  jdolecek static int limitpipekva = LIMITPIPEKVA;
    163       1.1  jdolecek 
    164       1.1  jdolecek /*
    165       1.1  jdolecek  * Limit the number of "big" pipes
    166       1.1  jdolecek  */
    167       1.2  jdolecek #define LIMITBIGPIPES  32
    168       1.2  jdolecek static int maxbigpipes = LIMITBIGPIPES;
    169       1.2  jdolecek static int nbigpipe = 0;
    170       1.1  jdolecek 
    171       1.2  jdolecek /*
    172       1.2  jdolecek  * Amount of KVA consumed by pipe buffers.
    173       1.2  jdolecek  */
    174       1.2  jdolecek static int amountpipekva = 0;
    175      1.34   thorpej 
    176      1.34   thorpej MALLOC_DEFINE(M_PIPE, "pipe", "Pipe structures");
    177       1.1  jdolecek 
    178      1.42  christos static void pipeclose(struct file *fp, struct pipe *pipe);
    179      1.35        pk static void pipe_free_kmem(struct pipe *pipe);
    180      1.35        pk static int pipe_create(struct pipe **pipep, int allockva);
    181      1.35        pk static int pipelock(struct pipe *pipe, int catch);
    182      1.70     perry static inline void pipeunlock(struct pipe *pipe);
    183      1.66  christos static void pipeselwakeup(struct pipe *pipe, struct pipe *sigp, int code);
    184       1.1  jdolecek #ifndef PIPE_NODIRECT
    185      1.42  christos static int pipe_direct_write(struct file *fp, struct pipe *wpipe,
    186      1.42  christos     struct uio *uio);
    187       1.1  jdolecek #endif
    188      1.35        pk static int pipespace(struct pipe *pipe, int size);
    189       1.2  jdolecek 
    190       1.2  jdolecek #ifndef PIPE_NODIRECT
    191      1.24  jdolecek static int pipe_loan_alloc(struct pipe *, int);
    192      1.24  jdolecek static void pipe_loan_free(struct pipe *);
    193       1.2  jdolecek #endif /* PIPE_NODIRECT */
    194       1.2  jdolecek 
    195      1.57    simonb static POOL_INIT(pipe_pool, sizeof(struct pipe), 0, 0, 0, "pipepl",
    196      1.57    simonb     &pool_allocator_nointr);
    197      1.24  jdolecek 
    198       1.1  jdolecek /*
    199       1.1  jdolecek  * The pipe system call for the DTYPE_PIPE type of pipes
    200       1.1  jdolecek  */
    201       1.1  jdolecek 
    202       1.1  jdolecek /* ARGSUSED */
    203       1.2  jdolecek int
    204      1.68   thorpej sys_pipe(struct lwp *l, void *v, register_t *retval)
    205       1.1  jdolecek {
    206       1.1  jdolecek 	struct file *rf, *wf;
    207      1.53       dsl 	struct pipe *rpipe, *wpipe;
    208       1.1  jdolecek 	int fd, error;
    209      1.33   thorpej 	struct proc *p;
    210       1.2  jdolecek 
    211      1.33   thorpej 	p = l->l_proc;
    212       1.6  jdolecek 	rpipe = wpipe = NULL;
    213       1.6  jdolecek 	if (pipe_create(&rpipe, 1) || pipe_create(&wpipe, 0)) {
    214      1.42  christos 		pipeclose(NULL, rpipe);
    215      1.42  christos 		pipeclose(NULL, wpipe);
    216       1.6  jdolecek 		return (ENFILE);
    217       1.6  jdolecek 	}
    218       1.6  jdolecek 
    219       1.2  jdolecek 	/*
    220       1.2  jdolecek 	 * Note: the file structure returned from falloc() is marked
    221       1.2  jdolecek 	 * as 'larval' initially. Unless we mark it as 'mature' by
    222       1.2  jdolecek 	 * FILE_SET_MATURE(), any attempt to do anything with it would
    223       1.2  jdolecek 	 * return EBADF, including e.g. dup(2) or close(2). This avoids
    224       1.2  jdolecek 	 * file descriptor races if we block in the second falloc().
    225       1.2  jdolecek 	 */
    226       1.2  jdolecek 
    227       1.2  jdolecek 	error = falloc(p, &rf, &fd);
    228       1.2  jdolecek 	if (error)
    229       1.2  jdolecek 		goto free2;
    230       1.2  jdolecek 	retval[0] = fd;
    231       1.2  jdolecek 	rf->f_flag = FREAD;
    232       1.2  jdolecek 	rf->f_type = DTYPE_PIPE;
    233       1.2  jdolecek 	rf->f_data = (caddr_t)rpipe;
    234       1.2  jdolecek 	rf->f_ops = &pipeops;
    235       1.2  jdolecek 
    236       1.2  jdolecek 	error = falloc(p, &wf, &fd);
    237       1.2  jdolecek 	if (error)
    238       1.2  jdolecek 		goto free3;
    239       1.2  jdolecek 	retval[1] = fd;
    240       1.2  jdolecek 	wf->f_flag = FWRITE;
    241       1.2  jdolecek 	wf->f_type = DTYPE_PIPE;
    242       1.2  jdolecek 	wf->f_data = (caddr_t)wpipe;
    243       1.2  jdolecek 	wf->f_ops = &pipeops;
    244       1.2  jdolecek 
    245       1.2  jdolecek 	rpipe->pipe_peer = wpipe;
    246       1.2  jdolecek 	wpipe->pipe_peer = rpipe;
    247       1.1  jdolecek 
    248       1.2  jdolecek 	FILE_SET_MATURE(rf);
    249       1.2  jdolecek 	FILE_SET_MATURE(wf);
    250      1.69  christos 	FILE_UNUSE(rf, l);
    251      1.69  christos 	FILE_UNUSE(wf, l);
    252       1.1  jdolecek 	return (0);
    253       1.2  jdolecek free3:
    254      1.69  christos 	FILE_UNUSE(rf, l);
    255       1.2  jdolecek 	ffree(rf);
    256      1.11  jdolecek 	fdremove(p->p_fd, retval[0]);
    257       1.2  jdolecek free2:
    258      1.42  christos 	pipeclose(NULL, wpipe);
    259      1.42  christos 	pipeclose(NULL, rpipe);
    260       1.2  jdolecek 
    261       1.2  jdolecek 	return (error);
    262       1.1  jdolecek }
    263       1.1  jdolecek 
    264       1.1  jdolecek /*
    265       1.1  jdolecek  * Allocate kva for pipe circular buffer, the space is pageable
    266       1.1  jdolecek  * This routine will 'realloc' the size of a pipe safely, if it fails
    267       1.1  jdolecek  * it will retain the old buffer.
    268       1.1  jdolecek  * If it fails it will return ENOMEM.
    269       1.1  jdolecek  */
    270       1.1  jdolecek static int
    271      1.68   thorpej pipespace(struct pipe *pipe, int size)
    272       1.1  jdolecek {
    273       1.2  jdolecek 	caddr_t buffer;
    274       1.2  jdolecek 	/*
    275      1.35        pk 	 * Allocate pageable virtual address space. Physical memory is
    276      1.35        pk 	 * allocated on demand.
    277       1.2  jdolecek 	 */
    278      1.65      yamt 	buffer = (caddr_t) uvm_km_alloc(kernel_map, round_page(size), 0,
    279      1.65      yamt 	    UVM_KMF_PAGEABLE);
    280       1.2  jdolecek 	if (buffer == NULL)
    281       1.2  jdolecek 		return (ENOMEM);
    282       1.1  jdolecek 
    283       1.1  jdolecek 	/* free old resources if we're resizing */
    284      1.35        pk 	pipe_free_kmem(pipe);
    285      1.35        pk 	pipe->pipe_buffer.buffer = buffer;
    286      1.35        pk 	pipe->pipe_buffer.size = size;
    287      1.35        pk 	pipe->pipe_buffer.in = 0;
    288      1.35        pk 	pipe->pipe_buffer.out = 0;
    289      1.35        pk 	pipe->pipe_buffer.cnt = 0;
    290      1.35        pk 	amountpipekva += pipe->pipe_buffer.size;
    291       1.1  jdolecek 	return (0);
    292       1.1  jdolecek }
    293       1.1  jdolecek 
    294       1.1  jdolecek /*
    295      1.35        pk  * Initialize and allocate VM and memory for pipe.
    296       1.1  jdolecek  */
    297       1.1  jdolecek static int
    298      1.68   thorpej pipe_create(struct pipe **pipep, int allockva)
    299       1.1  jdolecek {
    300      1.35        pk 	struct pipe *pipe;
    301       1.1  jdolecek 	int error;
    302       1.1  jdolecek 
    303      1.55     pooka 	pipe = *pipep = pool_get(&pipe_pool, PR_WAITOK);
    304       1.1  jdolecek 
    305      1.63     perry 	/* Initialize */
    306      1.35        pk 	memset(pipe, 0, sizeof(struct pipe));
    307      1.35        pk 	pipe->pipe_state = PIPE_SIGNALR;
    308       1.1  jdolecek 
    309  1.71.2.2      yamt 	getmicrotime(&pipe->pipe_ctime);
    310      1.35        pk 	pipe->pipe_atime = pipe->pipe_ctime;
    311      1.35        pk 	pipe->pipe_mtime = pipe->pipe_ctime;
    312      1.35        pk 	simple_lock_init(&pipe->pipe_slock);
    313       1.1  jdolecek 
    314      1.53       dsl 	if (allockva && (error = pipespace(pipe, PIPE_SIZE)))
    315      1.53       dsl 		return (error);
    316      1.53       dsl 
    317       1.1  jdolecek 	return (0);
    318       1.1  jdolecek }
    319       1.1  jdolecek 
    320       1.1  jdolecek 
    321       1.1  jdolecek /*
    322      1.35        pk  * Lock a pipe for I/O, blocking other access
    323      1.35        pk  * Called with pipe spin lock held.
    324      1.35        pk  * Return with pipe spin lock released on success.
    325       1.1  jdolecek  */
    326      1.35        pk static int
    327      1.68   thorpej pipelock(struct pipe *pipe, int catch)
    328       1.1  jdolecek {
    329       1.1  jdolecek 
    330      1.35        pk 	LOCK_ASSERT(simple_lock_held(&pipe->pipe_slock));
    331      1.35        pk 
    332      1.67      yamt 	while (pipe->pipe_state & PIPE_LOCKFL) {
    333      1.67      yamt 		int error;
    334      1.67      yamt 		const int pcatch = catch ? PCATCH : 0;
    335      1.35        pk 
    336      1.67      yamt 		pipe->pipe_state |= PIPE_LWANT;
    337      1.67      yamt 		error = ltsleep(pipe, PSOCK | pcatch, "pipelk", 0,
    338      1.51  jdolecek 		    &pipe->pipe_slock);
    339      1.67      yamt 		if (error != 0)
    340      1.67      yamt 			return error;
    341       1.1  jdolecek 	}
    342      1.67      yamt 
    343      1.67      yamt 	pipe->pipe_state |= PIPE_LOCKFL;
    344      1.67      yamt 	simple_unlock(&pipe->pipe_slock);
    345      1.67      yamt 
    346      1.67      yamt 	return 0;
    347       1.1  jdolecek }
    348       1.1  jdolecek 
    349       1.1  jdolecek /*
    350       1.1  jdolecek  * unlock a pipe I/O lock
    351       1.1  jdolecek  */
    352      1.70     perry static inline void
    353      1.68   thorpej pipeunlock(struct pipe *pipe)
    354       1.1  jdolecek {
    355      1.24  jdolecek 
    356      1.67      yamt 	KASSERT(pipe->pipe_state & PIPE_LOCKFL);
    357      1.67      yamt 
    358      1.67      yamt 	pipe->pipe_state &= ~PIPE_LOCKFL;
    359      1.67      yamt 	if (pipe->pipe_state & PIPE_LWANT) {
    360      1.67      yamt 		pipe->pipe_state &= ~PIPE_LWANT;
    361      1.67      yamt 		wakeup(pipe);
    362      1.67      yamt 	}
    363       1.1  jdolecek }
    364       1.1  jdolecek 
    365       1.2  jdolecek /*
    366       1.2  jdolecek  * Select/poll wakup. This also sends SIGIO to peer connected to
    367       1.2  jdolecek  * 'sigpipe' side of pipe.
    368       1.2  jdolecek  */
    369      1.35        pk static void
    370      1.68   thorpej pipeselwakeup(struct pipe *selp, struct pipe *sigp, int code)
    371       1.1  jdolecek {
    372      1.43  jdolecek 	int band;
    373      1.27  jdolecek 
    374      1.48  jdolecek 	selnotify(&selp->pipe_sel, NOTE_SUBMIT);
    375      1.43  jdolecek 
    376      1.35        pk 	if (sigp == NULL || (sigp->pipe_state & PIPE_ASYNC) == 0)
    377      1.35        pk 		return;
    378      1.35        pk 
    379      1.43  jdolecek 	switch (code) {
    380      1.42  christos 	case POLL_IN:
    381      1.43  jdolecek 		band = POLLIN|POLLRDNORM;
    382      1.42  christos 		break;
    383      1.42  christos 	case POLL_OUT:
    384      1.43  jdolecek 		band = POLLOUT|POLLWRNORM;
    385      1.42  christos 		break;
    386      1.42  christos 	case POLL_HUP:
    387      1.43  jdolecek 		band = POLLHUP;
    388      1.42  christos 		break;
    389      1.42  christos #if POLL_HUP != POLL_ERR
    390      1.42  christos 	case POLL_ERR:
    391      1.43  jdolecek 		band = POLLERR;
    392      1.42  christos 		break;
    393      1.42  christos #endif
    394      1.42  christos 	default:
    395      1.45  christos 		band = 0;
    396      1.42  christos #ifdef DIAGNOSTIC
    397      1.42  christos 		printf("bad siginfo code %d in pipe notification.\n", code);
    398      1.42  christos #endif
    399      1.42  christos 		break;
    400      1.42  christos 	}
    401      1.43  jdolecek 
    402      1.44  christos 	fownsignal(sigp->pipe_pgid, SIGIO, code, band, selp);
    403       1.1  jdolecek }
    404       1.1  jdolecek 
    405       1.1  jdolecek /* ARGSUSED */
    406       1.2  jdolecek static int
    407  1.71.2.1      yamt pipe_read(struct file *fp, off_t *offset, struct uio *uio, kauth_cred_t cred,
    408      1.68   thorpej     int flags)
    409       1.1  jdolecek {
    410       1.1  jdolecek 	struct pipe *rpipe = (struct pipe *) fp->f_data;
    411      1.35        pk 	struct pipebuf *bp = &rpipe->pipe_buffer;
    412       1.1  jdolecek 	int error;
    413       1.2  jdolecek 	size_t nread = 0;
    414       1.2  jdolecek 	size_t size;
    415       1.2  jdolecek 	size_t ocnt;
    416       1.1  jdolecek 
    417      1.24  jdolecek 	PIPE_LOCK(rpipe);
    418       1.1  jdolecek 	++rpipe->pipe_busy;
    419      1.35        pk 	ocnt = bp->cnt;
    420      1.28  jdolecek 
    421      1.35        pk again:
    422       1.1  jdolecek 	error = pipelock(rpipe, 1);
    423       1.1  jdolecek 	if (error)
    424       1.1  jdolecek 		goto unlocked_error;
    425       1.2  jdolecek 
    426       1.1  jdolecek 	while (uio->uio_resid) {
    427       1.1  jdolecek 		/*
    428       1.1  jdolecek 		 * normal pipe buffer receive
    429       1.1  jdolecek 		 */
    430      1.35        pk 		if (bp->cnt > 0) {
    431      1.35        pk 			size = bp->size - bp->out;
    432      1.35        pk 			if (size > bp->cnt)
    433      1.35        pk 				size = bp->cnt;
    434       1.2  jdolecek 			if (size > uio->uio_resid)
    435       1.2  jdolecek 				size = uio->uio_resid;
    436       1.1  jdolecek 
    437      1.35        pk 			error = uiomove(&bp->buffer[bp->out], size, uio);
    438       1.1  jdolecek 			if (error)
    439       1.1  jdolecek 				break;
    440       1.1  jdolecek 
    441      1.35        pk 			bp->out += size;
    442      1.35        pk 			if (bp->out >= bp->size)
    443      1.35        pk 				bp->out = 0;
    444       1.1  jdolecek 
    445      1.35        pk 			bp->cnt -= size;
    446       1.1  jdolecek 
    447       1.1  jdolecek 			/*
    448       1.1  jdolecek 			 * If there is no more to read in the pipe, reset
    449       1.1  jdolecek 			 * its pointers to the beginning.  This improves
    450       1.1  jdolecek 			 * cache hit stats.
    451       1.1  jdolecek 			 */
    452      1.35        pk 			if (bp->cnt == 0) {
    453      1.35        pk 				bp->in = 0;
    454      1.35        pk 				bp->out = 0;
    455       1.1  jdolecek 			}
    456       1.1  jdolecek 			nread += size;
    457       1.1  jdolecek #ifndef PIPE_NODIRECT
    458      1.35        pk 		} else if ((rpipe->pipe_state & PIPE_DIRECTR) != 0) {
    459      1.35        pk 			/*
    460      1.35        pk 			 * Direct copy, bypassing a kernel buffer.
    461      1.35        pk 			 */
    462       1.1  jdolecek 			caddr_t	va;
    463      1.35        pk 
    464      1.35        pk 			KASSERT(rpipe->pipe_state & PIPE_DIRECTW);
    465      1.35        pk 
    466      1.35        pk 			size = rpipe->pipe_map.cnt;
    467       1.2  jdolecek 			if (size > uio->uio_resid)
    468       1.2  jdolecek 				size = uio->uio_resid;
    469       1.1  jdolecek 
    470       1.1  jdolecek 			va = (caddr_t) rpipe->pipe_map.kva +
    471       1.1  jdolecek 			    rpipe->pipe_map.pos;
    472       1.1  jdolecek 			error = uiomove(va, size, uio);
    473       1.1  jdolecek 			if (error)
    474       1.1  jdolecek 				break;
    475       1.1  jdolecek 			nread += size;
    476       1.1  jdolecek 			rpipe->pipe_map.pos += size;
    477       1.1  jdolecek 			rpipe->pipe_map.cnt -= size;
    478       1.1  jdolecek 			if (rpipe->pipe_map.cnt == 0) {
    479      1.35        pk 				PIPE_LOCK(rpipe);
    480      1.35        pk 				rpipe->pipe_state &= ~PIPE_DIRECTR;
    481       1.1  jdolecek 				wakeup(rpipe);
    482      1.35        pk 				PIPE_UNLOCK(rpipe);
    483       1.1  jdolecek 			}
    484       1.1  jdolecek #endif
    485       1.1  jdolecek 		} else {
    486       1.1  jdolecek 			/*
    487      1.35        pk 			 * Break if some data was read.
    488       1.1  jdolecek 			 */
    489      1.35        pk 			if (nread > 0)
    490       1.1  jdolecek 				break;
    491       1.1  jdolecek 
    492      1.36        pk 			PIPE_LOCK(rpipe);
    493      1.36        pk 
    494       1.1  jdolecek 			/*
    495      1.36        pk 			 * detect EOF condition
    496      1.36        pk 			 * read returns 0 on EOF, no need to set error
    497       1.1  jdolecek 			 */
    498      1.36        pk 			if (rpipe->pipe_state & PIPE_EOF) {
    499      1.36        pk 				PIPE_UNLOCK(rpipe);
    500      1.35        pk 				break;
    501       1.1  jdolecek 			}
    502       1.1  jdolecek 
    503       1.1  jdolecek 			/*
    504      1.36        pk 			 * don't block on non-blocking I/O
    505       1.2  jdolecek 			 */
    506      1.36        pk 			if (fp->f_flag & FNONBLOCK) {
    507      1.35        pk 				PIPE_UNLOCK(rpipe);
    508      1.36        pk 				error = EAGAIN;
    509       1.2  jdolecek 				break;
    510       1.2  jdolecek 			}
    511       1.2  jdolecek 
    512       1.2  jdolecek 			/*
    513       1.2  jdolecek 			 * Unlock the pipe buffer for our remaining processing.
    514       1.2  jdolecek 			 * We will either break out with an error or we will
    515       1.2  jdolecek 			 * sleep and relock to loop.
    516       1.1  jdolecek 			 */
    517       1.1  jdolecek 			pipeunlock(rpipe);
    518       1.1  jdolecek 
    519       1.1  jdolecek 			/*
    520      1.35        pk 			 * The PIPE_DIRECTR flag is not under the control
    521      1.35        pk 			 * of the long-term lock (see pipe_direct_write()),
    522      1.35        pk 			 * so re-check now while holding the spin lock.
    523      1.35        pk 			 */
    524      1.35        pk 			if ((rpipe->pipe_state & PIPE_DIRECTR) != 0)
    525      1.35        pk 				goto again;
    526      1.35        pk 
    527      1.35        pk 			/*
    528       1.2  jdolecek 			 * We want to read more, wake up select/poll.
    529       1.1  jdolecek 			 */
    530      1.66  christos 			pipeselwakeup(rpipe, rpipe->pipe_peer, POLL_IN);
    531       1.2  jdolecek 
    532      1.35        pk 			/*
    533      1.35        pk 			 * If the "write-side" is blocked, wake it up now.
    534      1.35        pk 			 */
    535      1.35        pk 			if (rpipe->pipe_state & PIPE_WANTW) {
    536      1.35        pk 				rpipe->pipe_state &= ~PIPE_WANTW;
    537      1.35        pk 				wakeup(rpipe);
    538      1.35        pk 			}
    539      1.35        pk 
    540      1.35        pk 			/* Now wait until the pipe is filled */
    541       1.2  jdolecek 			rpipe->pipe_state |= PIPE_WANTR;
    542      1.58   mycroft 			error = ltsleep(rpipe, PSOCK | PCATCH,
    543      1.35        pk 					"piperd", 0, &rpipe->pipe_slock);
    544      1.35        pk 			if (error != 0)
    545       1.1  jdolecek 				goto unlocked_error;
    546      1.35        pk 			goto again;
    547       1.1  jdolecek 		}
    548       1.1  jdolecek 	}
    549      1.35        pk 
    550      1.35        pk 	if (error == 0)
    551  1.71.2.2      yamt 		getmicrotime(&rpipe->pipe_atime);
    552      1.35        pk 
    553      1.35        pk 	PIPE_LOCK(rpipe);
    554       1.1  jdolecek 	pipeunlock(rpipe);
    555       1.1  jdolecek 
    556       1.1  jdolecek unlocked_error:
    557       1.1  jdolecek 	--rpipe->pipe_busy;
    558       1.1  jdolecek 
    559       1.1  jdolecek 	/*
    560       1.2  jdolecek 	 * PIPE_WANTCLOSE processing only makes sense if pipe_busy is 0.
    561       1.1  jdolecek 	 */
    562       1.2  jdolecek 	if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANTCLOSE)) {
    563       1.2  jdolecek 		rpipe->pipe_state &= ~(PIPE_WANTCLOSE|PIPE_WANTW);
    564       1.1  jdolecek 		wakeup(rpipe);
    565      1.35        pk 	} else if (bp->cnt < MINPIPESIZE) {
    566       1.1  jdolecek 		/*
    567       1.1  jdolecek 		 * Handle write blocking hysteresis.
    568       1.1  jdolecek 		 */
    569       1.1  jdolecek 		if (rpipe->pipe_state & PIPE_WANTW) {
    570       1.1  jdolecek 			rpipe->pipe_state &= ~PIPE_WANTW;
    571       1.1  jdolecek 			wakeup(rpipe);
    572       1.1  jdolecek 		}
    573       1.1  jdolecek 	}
    574       1.1  jdolecek 
    575       1.2  jdolecek 	/*
    576       1.2  jdolecek 	 * If anything was read off the buffer, signal to the writer it's
    577       1.2  jdolecek 	 * possible to write more data. Also send signal if we are here for the
    578       1.2  jdolecek 	 * first time after last write.
    579       1.2  jdolecek 	 */
    580      1.35        pk 	if ((bp->size - bp->cnt) >= PIPE_BUF
    581      1.35        pk 	    && (ocnt != bp->cnt || (rpipe->pipe_state & PIPE_SIGNALR))) {
    582      1.66  christos 		pipeselwakeup(rpipe, rpipe->pipe_peer, POLL_OUT);
    583       1.2  jdolecek 		rpipe->pipe_state &= ~PIPE_SIGNALR;
    584       1.2  jdolecek 	}
    585       1.1  jdolecek 
    586      1.24  jdolecek 	PIPE_UNLOCK(rpipe);
    587       1.1  jdolecek 	return (error);
    588       1.1  jdolecek }
    589       1.1  jdolecek 
    590       1.2  jdolecek #ifndef PIPE_NODIRECT
    591       1.2  jdolecek /*
    592       1.2  jdolecek  * Allocate structure for loan transfer.
    593       1.2  jdolecek  */
    594      1.18       chs static int
    595      1.68   thorpej pipe_loan_alloc(struct pipe *wpipe, int npages)
    596       1.2  jdolecek {
    597      1.18       chs 	vsize_t len;
    598      1.18       chs 
    599      1.18       chs 	len = (vsize_t)npages << PAGE_SHIFT;
    600      1.65      yamt 	wpipe->pipe_map.kva = uvm_km_alloc(kernel_map, len, 0,
    601      1.65      yamt 	    UVM_KMF_VAONLY | UVM_KMF_WAITVA);
    602      1.22   thorpej 	if (wpipe->pipe_map.kva == 0)
    603       1.2  jdolecek 		return (ENOMEM);
    604       1.2  jdolecek 
    605      1.18       chs 	amountpipekva += len;
    606       1.2  jdolecek 	wpipe->pipe_map.npages = npages;
    607      1.18       chs 	wpipe->pipe_map.pgs = malloc(npages * sizeof(struct vm_page *), M_PIPE,
    608      1.18       chs 	    M_WAITOK);
    609       1.2  jdolecek 	return (0);
    610       1.2  jdolecek }
    611       1.2  jdolecek 
    612       1.2  jdolecek /*
    613       1.2  jdolecek  * Free resources allocated for loan transfer.
    614       1.2  jdolecek  */
    615       1.2  jdolecek static void
    616      1.68   thorpej pipe_loan_free(struct pipe *wpipe)
    617       1.2  jdolecek {
    618      1.18       chs 	vsize_t len;
    619      1.18       chs 
    620      1.18       chs 	len = (vsize_t)wpipe->pipe_map.npages << PAGE_SHIFT;
    621      1.65      yamt 	uvm_km_free(kernel_map, wpipe->pipe_map.kva, len, UVM_KMF_VAONLY);
    622      1.22   thorpej 	wpipe->pipe_map.kva = 0;
    623      1.18       chs 	amountpipekva -= len;
    624      1.18       chs 	free(wpipe->pipe_map.pgs, M_PIPE);
    625      1.18       chs 	wpipe->pipe_map.pgs = NULL;
    626       1.2  jdolecek }
    627       1.2  jdolecek 
    628       1.2  jdolecek /*
    629       1.2  jdolecek  * NetBSD direct write, using uvm_loan() mechanism.
    630       1.2  jdolecek  * This implements the pipe buffer write mechanism.  Note that only
    631       1.2  jdolecek  * a direct write OR a normal pipe write can be pending at any given time.
    632       1.2  jdolecek  * If there are any characters in the pipe buffer, the direct write will
    633       1.2  jdolecek  * be deferred until the receiving process grabs all of the bytes from
    634       1.2  jdolecek  * the pipe buffer.  Then the direct mapping write is set-up.
    635      1.35        pk  *
    636      1.35        pk  * Called with the long-term pipe lock held.
    637       1.2  jdolecek  */
    638      1.18       chs static int
    639      1.68   thorpej pipe_direct_write(struct file *fp, struct pipe *wpipe, struct uio *uio)
    640       1.2  jdolecek {
    641       1.5  jdolecek 	int error, npages, j;
    642      1.18       chs 	struct vm_page **pgs;
    643       1.2  jdolecek 	vaddr_t bbase, kva, base, bend;
    644       1.2  jdolecek 	vsize_t blen, bcnt;
    645       1.5  jdolecek 	voff_t bpos;
    646       1.5  jdolecek 
    647      1.35        pk 	KASSERT(wpipe->pipe_map.cnt == 0);
    648       1.2  jdolecek 
    649       1.2  jdolecek 	/*
    650      1.14  jdolecek 	 * Handle first PIPE_CHUNK_SIZE bytes of buffer. Deal with buffers
    651      1.14  jdolecek 	 * not aligned to PAGE_SIZE.
    652       1.5  jdolecek 	 */
    653      1.14  jdolecek 	bbase = (vaddr_t)uio->uio_iov->iov_base;
    654       1.5  jdolecek 	base = trunc_page(bbase);
    655      1.14  jdolecek 	bend = round_page(bbase + uio->uio_iov->iov_len);
    656       1.5  jdolecek 	blen = bend - base;
    657       1.5  jdolecek 	bpos = bbase - base;
    658       1.5  jdolecek 
    659       1.5  jdolecek 	if (blen > PIPE_DIRECT_CHUNK) {
    660       1.5  jdolecek 		blen = PIPE_DIRECT_CHUNK;
    661       1.5  jdolecek 		bend = base + blen;
    662       1.5  jdolecek 		bcnt = PIPE_DIRECT_CHUNK - bpos;
    663      1.18       chs 	} else {
    664      1.14  jdolecek 		bcnt = uio->uio_iov->iov_len;
    665      1.18       chs 	}
    666      1.18       chs 	npages = blen >> PAGE_SHIFT;
    667       1.5  jdolecek 
    668       1.5  jdolecek 	/*
    669       1.5  jdolecek 	 * Free the old kva if we need more pages than we have
    670       1.5  jdolecek 	 * allocated.
    671       1.2  jdolecek 	 */
    672      1.35        pk 	if (wpipe->pipe_map.kva != 0 && npages > wpipe->pipe_map.npages)
    673       1.5  jdolecek 		pipe_loan_free(wpipe);
    674       1.2  jdolecek 
    675       1.5  jdolecek 	/* Allocate new kva. */
    676      1.22   thorpej 	if (wpipe->pipe_map.kva == 0) {
    677      1.18       chs 		error = pipe_loan_alloc(wpipe, npages);
    678      1.35        pk 		if (error)
    679      1.35        pk 			return (error);
    680      1.18       chs 	}
    681      1.18       chs 
    682       1.5  jdolecek 	/* Loan the write buffer memory from writer process */
    683      1.18       chs 	pgs = wpipe->pipe_map.pgs;
    684      1.71      yamt 	error = uvm_loan(&uio->uio_vmspace->vm_map, base, blen,
    685      1.35        pk 			 pgs, UVM_LOAN_TOPAGE);
    686      1.18       chs 	if (error) {
    687      1.35        pk 		pipe_loan_free(wpipe);
    688      1.61      yamt 		return (ENOMEM); /* so that caller fallback to ordinary write */
    689      1.18       chs 	}
    690      1.18       chs 
    691       1.5  jdolecek 	/* Enter the loaned pages to kva */
    692       1.5  jdolecek 	kva = wpipe->pipe_map.kva;
    693      1.18       chs 	for (j = 0; j < npages; j++, kva += PAGE_SIZE) {
    694      1.18       chs 		pmap_kenter_pa(kva, VM_PAGE_TO_PHYS(pgs[j]), VM_PROT_READ);
    695      1.18       chs 	}
    696      1.12  jdolecek 	pmap_update(pmap_kernel());
    697       1.2  jdolecek 
    698      1.35        pk 	/* Now we can put the pipe in direct write mode */
    699      1.35        pk 	wpipe->pipe_map.pos = bpos;
    700      1.35        pk 	wpipe->pipe_map.cnt = bcnt;
    701       1.5  jdolecek 	wpipe->pipe_state |= PIPE_DIRECTW;
    702      1.35        pk 
    703      1.35        pk 	/*
    704      1.35        pk 	 * But before we can let someone do a direct read,
    705      1.35        pk 	 * we have to wait until the pipe is drained.
    706      1.35        pk 	 */
    707      1.35        pk 
    708      1.35        pk 	/* Relase the pipe lock while we wait */
    709      1.35        pk 	PIPE_LOCK(wpipe);
    710      1.35        pk 	pipeunlock(wpipe);
    711      1.35        pk 
    712      1.35        pk 	while (error == 0 && wpipe->pipe_buffer.cnt > 0) {
    713      1.35        pk 		if (wpipe->pipe_state & PIPE_WANTR) {
    714      1.35        pk 			wpipe->pipe_state &= ~PIPE_WANTR;
    715      1.35        pk 			wakeup(wpipe);
    716      1.35        pk 		}
    717      1.35        pk 
    718      1.35        pk 		wpipe->pipe_state |= PIPE_WANTW;
    719      1.58   mycroft 		error = ltsleep(wpipe, PSOCK | PCATCH, "pipdwc", 0,
    720      1.35        pk 				&wpipe->pipe_slock);
    721      1.35        pk 		if (error == 0 && wpipe->pipe_state & PIPE_EOF)
    722       1.5  jdolecek 			error = EPIPE;
    723      1.35        pk 	}
    724      1.35        pk 
    725      1.35        pk 	/* Pipe is drained; next read will off the direct buffer */
    726      1.35        pk 	wpipe->pipe_state |= PIPE_DIRECTR;
    727      1.35        pk 
    728      1.35        pk 	/* Wait until the reader is done */
    729      1.35        pk 	while (error == 0 && (wpipe->pipe_state & PIPE_DIRECTR)) {
    730       1.5  jdolecek 		if (wpipe->pipe_state & PIPE_WANTR) {
    731       1.5  jdolecek 			wpipe->pipe_state &= ~PIPE_WANTR;
    732       1.5  jdolecek 			wakeup(wpipe);
    733       1.2  jdolecek 		}
    734      1.66  christos 		pipeselwakeup(wpipe, wpipe, POLL_IN);
    735      1.58   mycroft 		error = ltsleep(wpipe, PSOCK | PCATCH, "pipdwt", 0,
    736      1.35        pk 				&wpipe->pipe_slock);
    737      1.35        pk 		if (error == 0 && wpipe->pipe_state & PIPE_EOF)
    738      1.35        pk 			error = EPIPE;
    739       1.5  jdolecek 	}
    740       1.5  jdolecek 
    741      1.35        pk 	/* Take pipe out of direct write mode */
    742      1.35        pk 	wpipe->pipe_state &= ~(PIPE_DIRECTW | PIPE_DIRECTR);
    743       1.2  jdolecek 
    744      1.35        pk 	/* Acquire the pipe lock and cleanup */
    745      1.35        pk 	(void)pipelock(wpipe, 0);
    746      1.21       chs 	if (pgs != NULL) {
    747      1.21       chs 		pmap_kremove(wpipe->pipe_map.kva, blen);
    748      1.18       chs 		uvm_unloan(pgs, npages, UVM_LOAN_TOPAGE);
    749      1.21       chs 	}
    750       1.5  jdolecek 	if (error || amountpipekva > maxpipekva)
    751       1.5  jdolecek 		pipe_loan_free(wpipe);
    752       1.5  jdolecek 
    753      1.15  jdolecek 	if (error) {
    754      1.66  christos 		pipeselwakeup(wpipe, wpipe, POLL_ERR);
    755       1.2  jdolecek 
    756       1.5  jdolecek 		/*
    757      1.15  jdolecek 		 * If nothing was read from what we offered, return error
    758      1.18       chs 		 * straight on. Otherwise update uio resid first. Caller
    759      1.15  jdolecek 		 * will deal with the error condition, returning short
    760      1.15  jdolecek 		 * write, error, or restarting the write(2) as appropriate.
    761       1.5  jdolecek 		 */
    762      1.15  jdolecek 		if (wpipe->pipe_map.cnt == bcnt) {
    763      1.35        pk 			wpipe->pipe_map.cnt = 0;
    764      1.15  jdolecek 			wakeup(wpipe);
    765      1.15  jdolecek 			return (error);
    766       1.2  jdolecek 		}
    767       1.2  jdolecek 
    768      1.15  jdolecek 		bcnt -= wpipe->pipe_map.cnt;
    769       1.5  jdolecek 	}
    770       1.2  jdolecek 
    771      1.18       chs 	uio->uio_resid -= bcnt;
    772       1.8  jdolecek 	/* uio_offset not updated, not set/used for write(2) */
    773      1.18       chs 	uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + bcnt;
    774      1.14  jdolecek 	uio->uio_iov->iov_len -= bcnt;
    775      1.14  jdolecek 	if (uio->uio_iov->iov_len == 0) {
    776      1.14  jdolecek 		uio->uio_iov++;
    777      1.14  jdolecek 		uio->uio_iovcnt--;
    778      1.14  jdolecek 	}
    779       1.2  jdolecek 
    780      1.35        pk 	wpipe->pipe_map.cnt = 0;
    781      1.15  jdolecek 	return (error);
    782       1.2  jdolecek }
    783       1.2  jdolecek #endif /* !PIPE_NODIRECT */
    784       1.2  jdolecek 
    785       1.2  jdolecek static int
    786  1.71.2.1      yamt pipe_write(struct file *fp, off_t *offset, struct uio *uio, kauth_cred_t cred,
    787      1.68   thorpej     int flags)
    788       1.1  jdolecek {
    789       1.1  jdolecek 	struct pipe *wpipe, *rpipe;
    790      1.35        pk 	struct pipebuf *bp;
    791      1.35        pk 	int error;
    792       1.1  jdolecek 
    793      1.35        pk 	/* We want to write to our peer */
    794       1.1  jdolecek 	rpipe = (struct pipe *) fp->f_data;
    795      1.35        pk 
    796      1.35        pk retry:
    797      1.35        pk 	error = 0;
    798      1.35        pk 	PIPE_LOCK(rpipe);
    799       1.1  jdolecek 	wpipe = rpipe->pipe_peer;
    800       1.1  jdolecek 
    801       1.1  jdolecek 	/*
    802      1.35        pk 	 * Detect loss of pipe read side, issue SIGPIPE if lost.
    803       1.1  jdolecek 	 */
    804      1.35        pk 	if (wpipe == NULL)
    805      1.35        pk 		error = EPIPE;
    806      1.35        pk 	else if (simple_lock_try(&wpipe->pipe_slock) == 0) {
    807      1.35        pk 		/* Deal with race for peer */
    808      1.24  jdolecek 		PIPE_UNLOCK(rpipe);
    809      1.35        pk 		goto retry;
    810      1.35        pk 	} else if ((wpipe->pipe_state & PIPE_EOF) != 0) {
    811      1.35        pk 		PIPE_UNLOCK(wpipe);
    812      1.35        pk 		error = EPIPE;
    813      1.24  jdolecek 	}
    814       1.2  jdolecek 
    815      1.35        pk 	PIPE_UNLOCK(rpipe);
    816      1.35        pk 	if (error != 0)
    817      1.35        pk 		return (error);
    818      1.35        pk 
    819       1.1  jdolecek 	++wpipe->pipe_busy;
    820       1.1  jdolecek 
    821      1.35        pk 	/* Aquire the long-term pipe lock */
    822      1.35        pk 	if ((error = pipelock(wpipe,1)) != 0) {
    823      1.35        pk 		--wpipe->pipe_busy;
    824      1.35        pk 		if (wpipe->pipe_busy == 0
    825      1.35        pk 		    && (wpipe->pipe_state & PIPE_WANTCLOSE)) {
    826      1.35        pk 			wpipe->pipe_state &= ~(PIPE_WANTCLOSE | PIPE_WANTR);
    827      1.35        pk 			wakeup(wpipe);
    828      1.35        pk 		}
    829      1.35        pk 		PIPE_UNLOCK(wpipe);
    830      1.35        pk 		return (error);
    831      1.35        pk 	}
    832      1.35        pk 
    833      1.35        pk 	bp = &wpipe->pipe_buffer;
    834      1.35        pk 
    835       1.1  jdolecek 	/*
    836      1.35        pk 	 * If it is advantageous to resize the pipe buffer, do so.
    837       1.1  jdolecek 	 */
    838       1.1  jdolecek 	if ((uio->uio_resid > PIPE_SIZE) &&
    839      1.35        pk 	    (nbigpipe < maxbigpipes) &&
    840       1.2  jdolecek #ifndef PIPE_NODIRECT
    841      1.35        pk 	    (wpipe->pipe_state & PIPE_DIRECTW) == 0 &&
    842       1.2  jdolecek #endif
    843      1.35        pk 	    (bp->size <= PIPE_SIZE) && (bp->cnt == 0)) {
    844       1.1  jdolecek 
    845      1.35        pk 		if (pipespace(wpipe, BIG_PIPE_SIZE) == 0)
    846      1.35        pk 			nbigpipe++;
    847      1.24  jdolecek 	}
    848       1.1  jdolecek 
    849       1.1  jdolecek 	while (uio->uio_resid) {
    850      1.26   thorpej 		size_t space;
    851       1.1  jdolecek 
    852       1.1  jdolecek #ifndef PIPE_NODIRECT
    853       1.1  jdolecek 		/*
    854      1.35        pk 		 * Pipe buffered writes cannot be coincidental with
    855      1.35        pk 		 * direct writes.  Also, only one direct write can be
    856      1.35        pk 		 * in progress at any one time.  We wait until the currently
    857      1.35        pk 		 * executing direct write is completed before continuing.
    858      1.35        pk 		 *
    859      1.35        pk 		 * We break out if a signal occurs or the reader goes away.
    860      1.35        pk 		 */
    861      1.35        pk 		while (error == 0 && wpipe->pipe_state & PIPE_DIRECTW) {
    862      1.35        pk 			PIPE_LOCK(wpipe);
    863      1.35        pk 			if (wpipe->pipe_state & PIPE_WANTR) {
    864      1.35        pk 				wpipe->pipe_state &= ~PIPE_WANTR;
    865      1.35        pk 				wakeup(wpipe);
    866      1.35        pk 			}
    867      1.35        pk 			pipeunlock(wpipe);
    868      1.58   mycroft 			error = ltsleep(wpipe, PSOCK | PCATCH,
    869      1.35        pk 					"pipbww", 0, &wpipe->pipe_slock);
    870      1.35        pk 
    871      1.35        pk 			(void)pipelock(wpipe, 0);
    872      1.35        pk 			if (wpipe->pipe_state & PIPE_EOF)
    873      1.35        pk 				error = EPIPE;
    874      1.35        pk 		}
    875      1.35        pk 		if (error)
    876      1.35        pk 			break;
    877      1.35        pk 
    878      1.35        pk 		/*
    879       1.1  jdolecek 		 * If the transfer is large, we can gain performance if
    880       1.1  jdolecek 		 * we do process-to-process copies directly.
    881       1.1  jdolecek 		 * If the write is non-blocking, we don't use the
    882       1.1  jdolecek 		 * direct write mechanism.
    883       1.1  jdolecek 		 *
    884       1.1  jdolecek 		 * The direct write mechanism will detect the reader going
    885       1.1  jdolecek 		 * away on us.
    886       1.1  jdolecek 		 */
    887      1.14  jdolecek 		if ((uio->uio_iov->iov_len >= PIPE_MINDIRECT) &&
    888       1.1  jdolecek 		    (fp->f_flag & FNONBLOCK) == 0 &&
    889       1.2  jdolecek 		    (wpipe->pipe_map.kva || (amountpipekva < limitpipekva))) {
    890      1.42  christos 			error = pipe_direct_write(fp, wpipe, uio);
    891       1.5  jdolecek 
    892       1.5  jdolecek 			/*
    893      1.49       wiz 			 * Break out if error occurred, unless it's ENOMEM.
    894      1.14  jdolecek 			 * ENOMEM means we failed to allocate some resources
    895      1.14  jdolecek 			 * for direct write, so we just fallback to ordinary
    896      1.14  jdolecek 			 * write. If the direct write was successful,
    897      1.14  jdolecek 			 * process rest of data via ordinary write.
    898       1.5  jdolecek 			 */
    899      1.35        pk 			if (error == 0)
    900      1.14  jdolecek 				continue;
    901      1.14  jdolecek 
    902       1.5  jdolecek 			if (error != ENOMEM)
    903       1.1  jdolecek 				break;
    904       1.1  jdolecek 		}
    905       1.2  jdolecek #endif /* PIPE_NODIRECT */
    906       1.1  jdolecek 
    907      1.35        pk 		space = bp->size - bp->cnt;
    908       1.1  jdolecek 
    909       1.1  jdolecek 		/* Writes of size <= PIPE_BUF must be atomic. */
    910      1.14  jdolecek 		if ((space < uio->uio_resid) && (uio->uio_resid <= PIPE_BUF))
    911       1.1  jdolecek 			space = 0;
    912       1.1  jdolecek 
    913      1.16   mycroft 		if (space > 0) {
    914       1.2  jdolecek 			int size;	/* Transfer size */
    915       1.2  jdolecek 			int segsize;	/* first segment to transfer */
    916       1.2  jdolecek 
    917       1.2  jdolecek 			/*
    918       1.2  jdolecek 			 * Transfer size is minimum of uio transfer
    919       1.2  jdolecek 			 * and free space in pipe buffer.
    920       1.2  jdolecek 			 */
    921       1.2  jdolecek 			if (space > uio->uio_resid)
    922       1.2  jdolecek 				size = uio->uio_resid;
    923       1.2  jdolecek 			else
    924       1.2  jdolecek 				size = space;
    925       1.2  jdolecek 			/*
    926      1.63     perry 			 * First segment to transfer is minimum of
    927       1.2  jdolecek 			 * transfer size and contiguous space in
    928       1.2  jdolecek 			 * pipe buffer.  If first segment to transfer
    929       1.2  jdolecek 			 * is less than the transfer size, we've got
    930       1.2  jdolecek 			 * a wraparound in the buffer.
    931       1.2  jdolecek 			 */
    932      1.35        pk 			segsize = bp->size - bp->in;
    933       1.2  jdolecek 			if (segsize > size)
    934       1.2  jdolecek 				segsize = size;
    935      1.18       chs 
    936       1.2  jdolecek 			/* Transfer first segment */
    937      1.35        pk 			error = uiomove(&bp->buffer[bp->in], segsize, uio);
    938      1.18       chs 
    939       1.2  jdolecek 			if (error == 0 && segsize < size) {
    940      1.63     perry 				/*
    941       1.2  jdolecek 				 * Transfer remaining part now, to
    942       1.2  jdolecek 				 * support atomic writes.  Wraparound
    943       1.2  jdolecek 				 * happened.
    944       1.2  jdolecek 				 */
    945       1.2  jdolecek #ifdef DEBUG
    946      1.35        pk 				if (bp->in + segsize != bp->size)
    947       1.2  jdolecek 					panic("Expected pipe buffer wraparound disappeared");
    948       1.2  jdolecek #endif
    949      1.18       chs 
    950      1.35        pk 				error = uiomove(&bp->buffer[0],
    951       1.2  jdolecek 						size - segsize, uio);
    952       1.2  jdolecek 			}
    953      1.35        pk 			if (error)
    954      1.35        pk 				break;
    955      1.35        pk 
    956      1.35        pk 			bp->in += size;
    957      1.35        pk 			if (bp->in >= bp->size) {
    958       1.2  jdolecek #ifdef DEBUG
    959      1.35        pk 				if (bp->in != size - segsize + bp->size)
    960      1.35        pk 					panic("Expected wraparound bad");
    961       1.2  jdolecek #endif
    962      1.35        pk 				bp->in = size - segsize;
    963      1.35        pk 			}
    964      1.18       chs 
    965      1.35        pk 			bp->cnt += size;
    966       1.2  jdolecek #ifdef DEBUG
    967      1.35        pk 			if (bp->cnt > bp->size)
    968      1.35        pk 				panic("Pipe buffer overflow");
    969       1.2  jdolecek #endif
    970       1.1  jdolecek 		} else {
    971       1.1  jdolecek 			/*
    972       1.1  jdolecek 			 * If the "read-side" has been blocked, wake it up now.
    973       1.1  jdolecek 			 */
    974      1.35        pk 			PIPE_LOCK(wpipe);
    975       1.1  jdolecek 			if (wpipe->pipe_state & PIPE_WANTR) {
    976       1.1  jdolecek 				wpipe->pipe_state &= ~PIPE_WANTR;
    977       1.1  jdolecek 				wakeup(wpipe);
    978       1.1  jdolecek 			}
    979      1.35        pk 			PIPE_UNLOCK(wpipe);
    980       1.1  jdolecek 
    981       1.1  jdolecek 			/*
    982       1.1  jdolecek 			 * don't block on non-blocking I/O
    983       1.1  jdolecek 			 */
    984       1.1  jdolecek 			if (fp->f_flag & FNONBLOCK) {
    985       1.1  jdolecek 				error = EAGAIN;
    986       1.1  jdolecek 				break;
    987       1.1  jdolecek 			}
    988       1.1  jdolecek 
    989       1.1  jdolecek 			/*
    990       1.1  jdolecek 			 * We have no more space and have something to offer,
    991       1.1  jdolecek 			 * wake up select/poll.
    992       1.1  jdolecek 			 */
    993      1.35        pk 			if (bp->cnt)
    994      1.66  christos 				pipeselwakeup(wpipe, wpipe, POLL_OUT);
    995       1.1  jdolecek 
    996      1.35        pk 			PIPE_LOCK(wpipe);
    997      1.35        pk 			pipeunlock(wpipe);
    998       1.1  jdolecek 			wpipe->pipe_state |= PIPE_WANTW;
    999      1.58   mycroft 			error = ltsleep(wpipe, PSOCK | PCATCH, "pipewr", 0,
   1000      1.35        pk 					&wpipe->pipe_slock);
   1001      1.35        pk 			(void)pipelock(wpipe, 0);
   1002       1.1  jdolecek 			if (error != 0)
   1003       1.1  jdolecek 				break;
   1004       1.1  jdolecek 			/*
   1005       1.1  jdolecek 			 * If read side wants to go away, we just issue a signal
   1006       1.1  jdolecek 			 * to ourselves.
   1007       1.1  jdolecek 			 */
   1008       1.1  jdolecek 			if (wpipe->pipe_state & PIPE_EOF) {
   1009       1.1  jdolecek 				error = EPIPE;
   1010       1.1  jdolecek 				break;
   1011      1.18       chs 			}
   1012       1.1  jdolecek 		}
   1013       1.1  jdolecek 	}
   1014       1.1  jdolecek 
   1015      1.35        pk 	PIPE_LOCK(wpipe);
   1016       1.1  jdolecek 	--wpipe->pipe_busy;
   1017       1.2  jdolecek 	if ((wpipe->pipe_busy == 0) && (wpipe->pipe_state & PIPE_WANTCLOSE)) {
   1018       1.2  jdolecek 		wpipe->pipe_state &= ~(PIPE_WANTCLOSE | PIPE_WANTR);
   1019       1.1  jdolecek 		wakeup(wpipe);
   1020      1.35        pk 	} else if (bp->cnt > 0) {
   1021       1.1  jdolecek 		/*
   1022       1.1  jdolecek 		 * If we have put any characters in the buffer, we wake up
   1023       1.1  jdolecek 		 * the reader.
   1024       1.1  jdolecek 		 */
   1025       1.1  jdolecek 		if (wpipe->pipe_state & PIPE_WANTR) {
   1026       1.1  jdolecek 			wpipe->pipe_state &= ~PIPE_WANTR;
   1027       1.1  jdolecek 			wakeup(wpipe);
   1028       1.1  jdolecek 		}
   1029       1.1  jdolecek 	}
   1030       1.1  jdolecek 
   1031       1.1  jdolecek 	/*
   1032       1.1  jdolecek 	 * Don't return EPIPE if I/O was successful
   1033       1.1  jdolecek 	 */
   1034      1.35        pk 	if (error == EPIPE && bp->cnt == 0 && uio->uio_resid == 0)
   1035       1.1  jdolecek 		error = 0;
   1036       1.1  jdolecek 
   1037       1.1  jdolecek 	if (error == 0)
   1038  1.71.2.2      yamt 		getmicrotime(&wpipe->pipe_mtime);
   1039       1.1  jdolecek 
   1040       1.1  jdolecek 	/*
   1041       1.2  jdolecek 	 * We have something to offer, wake up select/poll.
   1042       1.2  jdolecek 	 * wpipe->pipe_map.cnt is always 0 in this point (direct write
   1043      1.14  jdolecek 	 * is only done synchronously), so check only wpipe->pipe_buffer.cnt
   1044       1.1  jdolecek 	 */
   1045      1.35        pk 	if (bp->cnt)
   1046      1.66  christos 		pipeselwakeup(wpipe, wpipe, POLL_OUT);
   1047       1.1  jdolecek 
   1048       1.2  jdolecek 	/*
   1049       1.2  jdolecek 	 * Arrange for next read(2) to do a signal.
   1050       1.2  jdolecek 	 */
   1051       1.2  jdolecek 	wpipe->pipe_state |= PIPE_SIGNALR;
   1052       1.2  jdolecek 
   1053      1.35        pk 	pipeunlock(wpipe);
   1054      1.35        pk 	PIPE_UNLOCK(wpipe);
   1055       1.1  jdolecek 	return (error);
   1056       1.1  jdolecek }
   1057       1.1  jdolecek 
   1058       1.1  jdolecek /*
   1059       1.1  jdolecek  * we implement a very minimal set of ioctls for compatibility with sockets.
   1060       1.1  jdolecek  */
   1061       1.1  jdolecek int
   1062      1.69  christos pipe_ioctl(struct file *fp, u_long cmd, void *data, struct lwp *l)
   1063       1.1  jdolecek {
   1064      1.35        pk 	struct pipe *pipe = (struct pipe *)fp->f_data;
   1065      1.69  christos 	struct proc *p = l->l_proc;
   1066       1.1  jdolecek 
   1067       1.1  jdolecek 	switch (cmd) {
   1068       1.1  jdolecek 
   1069       1.1  jdolecek 	case FIONBIO:
   1070       1.1  jdolecek 		return (0);
   1071       1.1  jdolecek 
   1072       1.1  jdolecek 	case FIOASYNC:
   1073      1.35        pk 		PIPE_LOCK(pipe);
   1074       1.1  jdolecek 		if (*(int *)data) {
   1075      1.35        pk 			pipe->pipe_state |= PIPE_ASYNC;
   1076       1.1  jdolecek 		} else {
   1077      1.35        pk 			pipe->pipe_state &= ~PIPE_ASYNC;
   1078       1.1  jdolecek 		}
   1079      1.35        pk 		PIPE_UNLOCK(pipe);
   1080       1.1  jdolecek 		return (0);
   1081       1.1  jdolecek 
   1082       1.1  jdolecek 	case FIONREAD:
   1083      1.35        pk 		PIPE_LOCK(pipe);
   1084       1.2  jdolecek #ifndef PIPE_NODIRECT
   1085      1.35        pk 		if (pipe->pipe_state & PIPE_DIRECTW)
   1086      1.35        pk 			*(int *)data = pipe->pipe_map.cnt;
   1087       1.1  jdolecek 		else
   1088       1.2  jdolecek #endif
   1089      1.35        pk 			*(int *)data = pipe->pipe_buffer.cnt;
   1090      1.35        pk 		PIPE_UNLOCK(pipe);
   1091       1.1  jdolecek 		return (0);
   1092       1.1  jdolecek 
   1093      1.59  wrstuden 	case FIONWRITE:
   1094      1.59  wrstuden 		/* Look at other side */
   1095      1.59  wrstuden 		pipe = pipe->pipe_peer;
   1096      1.59  wrstuden 		PIPE_LOCK(pipe);
   1097      1.59  wrstuden #ifndef PIPE_NODIRECT
   1098      1.59  wrstuden 		if (pipe->pipe_state & PIPE_DIRECTW)
   1099      1.59  wrstuden 			*(int *)data = pipe->pipe_map.cnt;
   1100      1.59  wrstuden 		else
   1101      1.59  wrstuden #endif
   1102      1.59  wrstuden 			*(int *)data = pipe->pipe_buffer.cnt;
   1103      1.59  wrstuden 		PIPE_UNLOCK(pipe);
   1104      1.59  wrstuden 		return (0);
   1105      1.59  wrstuden 
   1106      1.59  wrstuden 	case FIONSPACE:
   1107      1.59  wrstuden 		/* Look at other side */
   1108      1.59  wrstuden 		pipe = pipe->pipe_peer;
   1109      1.59  wrstuden 		PIPE_LOCK(pipe);
   1110      1.59  wrstuden #ifndef PIPE_NODIRECT
   1111      1.59  wrstuden 		/*
   1112      1.59  wrstuden 		 * If we're in direct-mode, we don't really have a
   1113      1.59  wrstuden 		 * send queue, and any other write will block. Thus
   1114      1.59  wrstuden 		 * zero seems like the best answer.
   1115      1.59  wrstuden 		 */
   1116      1.59  wrstuden 		if (pipe->pipe_state & PIPE_DIRECTW)
   1117      1.59  wrstuden 			*(int *)data = 0;
   1118      1.59  wrstuden 		else
   1119      1.59  wrstuden #endif
   1120      1.59  wrstuden 			*(int *)data = pipe->pipe_buffer.size -
   1121      1.59  wrstuden 					pipe->pipe_buffer.cnt;
   1122      1.59  wrstuden 		PIPE_UNLOCK(pipe);
   1123      1.59  wrstuden 		return (0);
   1124      1.59  wrstuden 
   1125       1.2  jdolecek 	case TIOCSPGRP:
   1126      1.43  jdolecek 	case FIOSETOWN:
   1127      1.43  jdolecek 		return fsetown(p, &pipe->pipe_pgid, cmd, data);
   1128       1.2  jdolecek 
   1129       1.2  jdolecek 	case TIOCGPGRP:
   1130      1.43  jdolecek 	case FIOGETOWN:
   1131      1.43  jdolecek 		return fgetown(p, pipe->pipe_pgid, cmd, data);
   1132       1.1  jdolecek 
   1133       1.1  jdolecek 	}
   1134      1.25    atatat 	return (EPASSTHROUGH);
   1135       1.1  jdolecek }
   1136       1.1  jdolecek 
   1137       1.1  jdolecek int
   1138      1.69  christos pipe_poll(struct file *fp, int events, struct lwp *l)
   1139       1.1  jdolecek {
   1140       1.1  jdolecek 	struct pipe *rpipe = (struct pipe *)fp->f_data;
   1141       1.1  jdolecek 	struct pipe *wpipe;
   1142      1.35        pk 	int eof = 0;
   1143       1.1  jdolecek 	int revents = 0;
   1144       1.1  jdolecek 
   1145      1.35        pk retry:
   1146      1.35        pk 	PIPE_LOCK(rpipe);
   1147       1.1  jdolecek 	wpipe = rpipe->pipe_peer;
   1148      1.35        pk 	if (wpipe != NULL && simple_lock_try(&wpipe->pipe_slock) == 0) {
   1149      1.35        pk 		/* Deal with race for peer */
   1150      1.35        pk 		PIPE_UNLOCK(rpipe);
   1151      1.35        pk 		goto retry;
   1152      1.35        pk 	}
   1153      1.35        pk 
   1154       1.1  jdolecek 	if (events & (POLLIN | POLLRDNORM))
   1155       1.2  jdolecek 		if ((rpipe->pipe_buffer.cnt > 0) ||
   1156       1.2  jdolecek #ifndef PIPE_NODIRECT
   1157      1.35        pk 		    (rpipe->pipe_state & PIPE_DIRECTR) ||
   1158       1.2  jdolecek #endif
   1159       1.1  jdolecek 		    (rpipe->pipe_state & PIPE_EOF))
   1160       1.1  jdolecek 			revents |= events & (POLLIN | POLLRDNORM);
   1161       1.1  jdolecek 
   1162      1.35        pk 	eof |= (rpipe->pipe_state & PIPE_EOF);
   1163      1.35        pk 	PIPE_UNLOCK(rpipe);
   1164      1.35        pk 
   1165      1.35        pk 	if (wpipe == NULL)
   1166      1.35        pk 		revents |= events & (POLLOUT | POLLWRNORM);
   1167      1.35        pk 	else {
   1168      1.35        pk 		if (events & (POLLOUT | POLLWRNORM))
   1169      1.35        pk 			if ((wpipe->pipe_state & PIPE_EOF) || (
   1170       1.2  jdolecek #ifndef PIPE_NODIRECT
   1171      1.35        pk 			     (wpipe->pipe_state & PIPE_DIRECTW) == 0 &&
   1172       1.2  jdolecek #endif
   1173      1.35        pk 			     (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF))
   1174      1.35        pk 				revents |= events & (POLLOUT | POLLWRNORM);
   1175       1.1  jdolecek 
   1176      1.35        pk 		eof |= (wpipe->pipe_state & PIPE_EOF);
   1177      1.35        pk 		PIPE_UNLOCK(wpipe);
   1178      1.35        pk 	}
   1179      1.35        pk 
   1180      1.35        pk 	if (wpipe == NULL || eof)
   1181       1.1  jdolecek 		revents |= POLLHUP;
   1182       1.1  jdolecek 
   1183       1.1  jdolecek 	if (revents == 0) {
   1184      1.35        pk 		if (events & (POLLIN | POLLRDNORM))
   1185      1.69  christos 			selrecord(l, &rpipe->pipe_sel);
   1186       1.1  jdolecek 
   1187      1.35        pk 		if (events & (POLLOUT | POLLWRNORM))
   1188      1.69  christos 			selrecord(l, &wpipe->pipe_sel);
   1189       1.1  jdolecek 	}
   1190       1.1  jdolecek 
   1191       1.1  jdolecek 	return (revents);
   1192       1.1  jdolecek }
   1193       1.1  jdolecek 
   1194       1.1  jdolecek static int
   1195      1.69  christos pipe_stat(struct file *fp, struct stat *ub, struct lwp *l)
   1196       1.1  jdolecek {
   1197       1.1  jdolecek 	struct pipe *pipe = (struct pipe *)fp->f_data;
   1198       1.1  jdolecek 
   1199       1.9   thorpej 	memset((caddr_t)ub, 0, sizeof(*ub));
   1200      1.32  jdolecek 	ub->st_mode = S_IFIFO | S_IRUSR | S_IWUSR;
   1201       1.1  jdolecek 	ub->st_blksize = pipe->pipe_buffer.size;
   1202      1.64  christos 	if (ub->st_blksize == 0 && pipe->pipe_peer)
   1203      1.64  christos 		ub->st_blksize = pipe->pipe_peer->pipe_buffer.size;
   1204       1.1  jdolecek 	ub->st_size = pipe->pipe_buffer.cnt;
   1205       1.2  jdolecek 	ub->st_blocks = (ub->st_size) ? 1 : 0;
   1206      1.60    atatat 	TIMEVAL_TO_TIMESPEC(&pipe->pipe_atime, &ub->st_atimespec);
   1207       1.2  jdolecek 	TIMEVAL_TO_TIMESPEC(&pipe->pipe_mtime, &ub->st_mtimespec);
   1208       1.2  jdolecek 	TIMEVAL_TO_TIMESPEC(&pipe->pipe_ctime, &ub->st_ctimespec);
   1209  1.71.2.1      yamt 	ub->st_uid = kauth_cred_geteuid(fp->f_cred);
   1210  1.71.2.1      yamt 	ub->st_gid = kauth_cred_getegid(fp->f_cred);
   1211       1.1  jdolecek 	/*
   1212       1.1  jdolecek 	 * Left as 0: st_dev, st_ino, st_nlink, st_rdev, st_flags, st_gen.
   1213       1.1  jdolecek 	 * XXX (st_dev, st_ino) should be unique.
   1214       1.1  jdolecek 	 */
   1215       1.1  jdolecek 	return (0);
   1216       1.1  jdolecek }
   1217       1.1  jdolecek 
   1218       1.1  jdolecek /* ARGSUSED */
   1219       1.1  jdolecek static int
   1220      1.69  christos pipe_close(struct file *fp, struct lwp *l)
   1221       1.1  jdolecek {
   1222      1.35        pk 	struct pipe *pipe = (struct pipe *)fp->f_data;
   1223       1.1  jdolecek 
   1224       1.1  jdolecek 	fp->f_data = NULL;
   1225      1.42  christos 	pipeclose(fp, pipe);
   1226       1.1  jdolecek 	return (0);
   1227       1.1  jdolecek }
   1228       1.1  jdolecek 
   1229       1.1  jdolecek static void
   1230      1.68   thorpej pipe_free_kmem(struct pipe *pipe)
   1231       1.1  jdolecek {
   1232       1.1  jdolecek 
   1233      1.35        pk 	if (pipe->pipe_buffer.buffer != NULL) {
   1234      1.35        pk 		if (pipe->pipe_buffer.size > PIPE_SIZE)
   1235       1.1  jdolecek 			--nbigpipe;
   1236      1.35        pk 		amountpipekva -= pipe->pipe_buffer.size;
   1237       1.2  jdolecek 		uvm_km_free(kernel_map,
   1238      1.35        pk 			(vaddr_t)pipe->pipe_buffer.buffer,
   1239      1.65      yamt 			pipe->pipe_buffer.size, UVM_KMF_PAGEABLE);
   1240      1.35        pk 		pipe->pipe_buffer.buffer = NULL;
   1241       1.1  jdolecek 	}
   1242       1.1  jdolecek #ifndef PIPE_NODIRECT
   1243      1.35        pk 	if (pipe->pipe_map.kva != 0) {
   1244      1.35        pk 		pipe_loan_free(pipe);
   1245      1.35        pk 		pipe->pipe_map.cnt = 0;
   1246      1.35        pk 		pipe->pipe_map.kva = 0;
   1247      1.35        pk 		pipe->pipe_map.pos = 0;
   1248      1.35        pk 		pipe->pipe_map.npages = 0;
   1249       1.1  jdolecek 	}
   1250       1.2  jdolecek #endif /* !PIPE_NODIRECT */
   1251       1.1  jdolecek }
   1252       1.1  jdolecek 
   1253       1.1  jdolecek /*
   1254       1.1  jdolecek  * shutdown the pipe
   1255       1.1  jdolecek  */
   1256       1.1  jdolecek static void
   1257      1.68   thorpej pipeclose(struct file *fp, struct pipe *pipe)
   1258       1.1  jdolecek {
   1259       1.1  jdolecek 	struct pipe *ppipe;
   1260       1.1  jdolecek 
   1261      1.35        pk 	if (pipe == NULL)
   1262       1.2  jdolecek 		return;
   1263       1.2  jdolecek 
   1264      1.35        pk retry:
   1265      1.35        pk 	PIPE_LOCK(pipe);
   1266      1.35        pk 
   1267      1.66  christos 	pipeselwakeup(pipe, pipe, POLL_HUP);
   1268       1.1  jdolecek 
   1269       1.2  jdolecek 	/*
   1270       1.2  jdolecek 	 * If the other side is blocked, wake it up saying that
   1271       1.2  jdolecek 	 * we want to close it down.
   1272       1.2  jdolecek 	 */
   1273      1.66  christos 	pipe->pipe_state |= PIPE_EOF;
   1274      1.35        pk 	while (pipe->pipe_busy) {
   1275      1.35        pk 		wakeup(pipe);
   1276      1.66  christos 		pipe->pipe_state |= PIPE_WANTCLOSE;
   1277      1.58   mycroft 		ltsleep(pipe, PSOCK, "pipecl", 0, &pipe->pipe_slock);
   1278       1.2  jdolecek 	}
   1279       1.1  jdolecek 
   1280       1.2  jdolecek 	/*
   1281       1.2  jdolecek 	 * Disconnect from peer
   1282       1.2  jdolecek 	 */
   1283      1.35        pk 	if ((ppipe = pipe->pipe_peer) != NULL) {
   1284      1.35        pk 		/* Deal with race for peer */
   1285      1.35        pk 		if (simple_lock_try(&ppipe->pipe_slock) == 0) {
   1286      1.35        pk 			PIPE_UNLOCK(pipe);
   1287      1.35        pk 			goto retry;
   1288      1.35        pk 		}
   1289      1.66  christos 		pipeselwakeup(ppipe, ppipe, POLL_HUP);
   1290       1.1  jdolecek 
   1291       1.2  jdolecek 		ppipe->pipe_state |= PIPE_EOF;
   1292       1.2  jdolecek 		wakeup(ppipe);
   1293       1.2  jdolecek 		ppipe->pipe_peer = NULL;
   1294      1.35        pk 		PIPE_UNLOCK(ppipe);
   1295       1.1  jdolecek 	}
   1296      1.35        pk 
   1297      1.67      yamt 	KASSERT((pipe->pipe_state & PIPE_LOCKFL) == 0);
   1298      1.67      yamt 
   1299      1.67      yamt 	PIPE_UNLOCK(pipe);
   1300      1.35        pk 
   1301       1.2  jdolecek 	/*
   1302       1.2  jdolecek 	 * free resources
   1303       1.2  jdolecek 	 */
   1304      1.35        pk 	pipe_free_kmem(pipe);
   1305      1.35        pk 	pool_put(&pipe_pool, pipe);
   1306       1.1  jdolecek }
   1307       1.1  jdolecek 
   1308      1.27  jdolecek static void
   1309      1.27  jdolecek filt_pipedetach(struct knote *kn)
   1310       1.1  jdolecek {
   1311      1.35        pk 	struct pipe *pipe = (struct pipe *)kn->kn_fp->f_data;
   1312       1.1  jdolecek 
   1313      1.27  jdolecek 	switch(kn->kn_filter) {
   1314       1.1  jdolecek 	case EVFILT_WRITE:
   1315      1.27  jdolecek 		/* need the peer structure, not our own */
   1316      1.35        pk 		pipe = pipe->pipe_peer;
   1317      1.35        pk 		/* XXXSMP: race for peer */
   1318      1.27  jdolecek 
   1319      1.27  jdolecek 		/* if reader end already closed, just return */
   1320      1.35        pk 		if (pipe == NULL)
   1321      1.27  jdolecek 			return;
   1322      1.27  jdolecek 
   1323       1.1  jdolecek 		break;
   1324       1.1  jdolecek 	default:
   1325      1.27  jdolecek 		/* nothing to do */
   1326      1.29  kristerw 		break;
   1327       1.1  jdolecek 	}
   1328      1.24  jdolecek 
   1329      1.27  jdolecek #ifdef DIAGNOSTIC
   1330      1.35        pk 	if (kn->kn_hook != pipe)
   1331      1.27  jdolecek 		panic("filt_pipedetach: inconsistent knote");
   1332      1.27  jdolecek #endif
   1333       1.1  jdolecek 
   1334      1.35        pk 	PIPE_LOCK(pipe);
   1335      1.35        pk 	SLIST_REMOVE(&pipe->pipe_sel.sel_klist, kn, knote, kn_selnext);
   1336      1.35        pk 	PIPE_UNLOCK(pipe);
   1337       1.1  jdolecek }
   1338       1.1  jdolecek 
   1339       1.1  jdolecek /*ARGSUSED*/
   1340       1.1  jdolecek static int
   1341       1.1  jdolecek filt_piperead(struct knote *kn, long hint)
   1342       1.1  jdolecek {
   1343       1.1  jdolecek 	struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data;
   1344       1.1  jdolecek 	struct pipe *wpipe = rpipe->pipe_peer;
   1345       1.1  jdolecek 
   1346      1.48  jdolecek 	if ((hint & NOTE_SUBMIT) == 0)
   1347      1.48  jdolecek 		PIPE_LOCK(rpipe);
   1348       1.1  jdolecek 	kn->kn_data = rpipe->pipe_buffer.cnt;
   1349       1.1  jdolecek 	if ((kn->kn_data == 0) && (rpipe->pipe_state & PIPE_DIRECTW))
   1350       1.1  jdolecek 		kn->kn_data = rpipe->pipe_map.cnt;
   1351       1.1  jdolecek 
   1352      1.35        pk 	/* XXXSMP: race for peer */
   1353       1.1  jdolecek 	if ((rpipe->pipe_state & PIPE_EOF) ||
   1354       1.1  jdolecek 	    (wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) {
   1355      1.24  jdolecek 		kn->kn_flags |= EV_EOF;
   1356      1.48  jdolecek 		if ((hint & NOTE_SUBMIT) == 0)
   1357      1.48  jdolecek 			PIPE_UNLOCK(rpipe);
   1358       1.1  jdolecek 		return (1);
   1359       1.1  jdolecek 	}
   1360      1.48  jdolecek 	if ((hint & NOTE_SUBMIT) == 0)
   1361      1.48  jdolecek 		PIPE_UNLOCK(rpipe);
   1362       1.1  jdolecek 	return (kn->kn_data > 0);
   1363       1.1  jdolecek }
   1364       1.1  jdolecek 
   1365       1.1  jdolecek /*ARGSUSED*/
   1366       1.1  jdolecek static int
   1367       1.1  jdolecek filt_pipewrite(struct knote *kn, long hint)
   1368       1.1  jdolecek {
   1369       1.1  jdolecek 	struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data;
   1370       1.1  jdolecek 	struct pipe *wpipe = rpipe->pipe_peer;
   1371       1.1  jdolecek 
   1372      1.48  jdolecek 	if ((hint & NOTE_SUBMIT) == 0)
   1373      1.48  jdolecek 		PIPE_LOCK(rpipe);
   1374      1.35        pk 	/* XXXSMP: race for peer */
   1375       1.1  jdolecek 	if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) {
   1376       1.1  jdolecek 		kn->kn_data = 0;
   1377      1.63     perry 		kn->kn_flags |= EV_EOF;
   1378      1.48  jdolecek 		if ((hint & NOTE_SUBMIT) == 0)
   1379      1.48  jdolecek 			PIPE_UNLOCK(rpipe);
   1380       1.1  jdolecek 		return (1);
   1381       1.1  jdolecek 	}
   1382       1.1  jdolecek 	kn->kn_data = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt;
   1383       1.1  jdolecek 	if (wpipe->pipe_state & PIPE_DIRECTW)
   1384       1.1  jdolecek 		kn->kn_data = 0;
   1385       1.1  jdolecek 
   1386      1.48  jdolecek 	if ((hint & NOTE_SUBMIT) == 0)
   1387      1.48  jdolecek 		PIPE_UNLOCK(rpipe);
   1388       1.1  jdolecek 	return (kn->kn_data >= PIPE_BUF);
   1389       1.1  jdolecek }
   1390      1.27  jdolecek 
   1391      1.27  jdolecek static const struct filterops pipe_rfiltops =
   1392      1.27  jdolecek 	{ 1, NULL, filt_pipedetach, filt_piperead };
   1393      1.27  jdolecek static const struct filterops pipe_wfiltops =
   1394      1.27  jdolecek 	{ 1, NULL, filt_pipedetach, filt_pipewrite };
   1395      1.27  jdolecek 
   1396      1.27  jdolecek /*ARGSUSED*/
   1397      1.27  jdolecek static int
   1398      1.27  jdolecek pipe_kqfilter(struct file *fp, struct knote *kn)
   1399      1.27  jdolecek {
   1400      1.35        pk 	struct pipe *pipe;
   1401      1.27  jdolecek 
   1402      1.35        pk 	pipe = (struct pipe *)kn->kn_fp->f_data;
   1403      1.27  jdolecek 	switch (kn->kn_filter) {
   1404      1.27  jdolecek 	case EVFILT_READ:
   1405      1.27  jdolecek 		kn->kn_fop = &pipe_rfiltops;
   1406      1.27  jdolecek 		break;
   1407      1.27  jdolecek 	case EVFILT_WRITE:
   1408      1.27  jdolecek 		kn->kn_fop = &pipe_wfiltops;
   1409      1.35        pk 		/* XXXSMP: race for peer */
   1410      1.35        pk 		pipe = pipe->pipe_peer;
   1411      1.35        pk 		if (pipe == NULL) {
   1412      1.27  jdolecek 			/* other end of pipe has been closed */
   1413      1.27  jdolecek 			return (EBADF);
   1414      1.27  jdolecek 		}
   1415      1.27  jdolecek 		break;
   1416      1.27  jdolecek 	default:
   1417      1.27  jdolecek 		return (1);
   1418      1.27  jdolecek 	}
   1419      1.35        pk 	kn->kn_hook = pipe;
   1420      1.27  jdolecek 
   1421      1.35        pk 	PIPE_LOCK(pipe);
   1422      1.35        pk 	SLIST_INSERT_HEAD(&pipe->pipe_sel.sel_klist, kn, kn_selnext);
   1423      1.35        pk 	PIPE_UNLOCK(pipe);
   1424      1.27  jdolecek 	return (0);
   1425      1.27  jdolecek }
   1426       1.2  jdolecek 
   1427       1.2  jdolecek /*
   1428       1.2  jdolecek  * Handle pipe sysctls.
   1429       1.2  jdolecek  */
   1430      1.47    atatat SYSCTL_SETUP(sysctl_kern_pipe_setup, "sysctl kern.pipe subtree setup")
   1431      1.47    atatat {
   1432      1.47    atatat 
   1433      1.54    atatat 	sysctl_createv(clog, 0, NULL, NULL,
   1434      1.54    atatat 		       CTLFLAG_PERMANENT,
   1435      1.47    atatat 		       CTLTYPE_NODE, "kern", NULL,
   1436      1.47    atatat 		       NULL, 0, NULL, 0,
   1437      1.47    atatat 		       CTL_KERN, CTL_EOL);
   1438      1.54    atatat 	sysctl_createv(clog, 0, NULL, NULL,
   1439      1.54    atatat 		       CTLFLAG_PERMANENT,
   1440      1.56    atatat 		       CTLTYPE_NODE, "pipe",
   1441      1.56    atatat 		       SYSCTL_DESCR("Pipe settings"),
   1442      1.47    atatat 		       NULL, 0, NULL, 0,
   1443      1.47    atatat 		       CTL_KERN, KERN_PIPE, CTL_EOL);
   1444      1.47    atatat 
   1445      1.54    atatat 	sysctl_createv(clog, 0, NULL, NULL,
   1446      1.54    atatat 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1447      1.56    atatat 		       CTLTYPE_INT, "maxkvasz",
   1448      1.56    atatat 		       SYSCTL_DESCR("Maximum amount of kernel memory to be "
   1449      1.56    atatat 				    "used for pipes"),
   1450      1.47    atatat 		       NULL, 0, &maxpipekva, 0,
   1451      1.47    atatat 		       CTL_KERN, KERN_PIPE, KERN_PIPE_MAXKVASZ, CTL_EOL);
   1452      1.54    atatat 	sysctl_createv(clog, 0, NULL, NULL,
   1453      1.54    atatat 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1454      1.56    atatat 		       CTLTYPE_INT, "maxloankvasz",
   1455      1.56    atatat 		       SYSCTL_DESCR("Limit for direct transfers via page loan"),
   1456      1.47    atatat 		       NULL, 0, &limitpipekva, 0,
   1457      1.47    atatat 		       CTL_KERN, KERN_PIPE, KERN_PIPE_LIMITKVA, CTL_EOL);
   1458      1.54    atatat 	sysctl_createv(clog, 0, NULL, NULL,
   1459      1.54    atatat 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1460      1.56    atatat 		       CTLTYPE_INT, "maxbigpipes",
   1461      1.56    atatat 		       SYSCTL_DESCR("Maximum number of \"big\" pipes"),
   1462      1.47    atatat 		       NULL, 0, &maxbigpipes, 0,
   1463      1.47    atatat 		       CTL_KERN, KERN_PIPE, KERN_PIPE_MAXBIGPIPES, CTL_EOL);
   1464      1.54    atatat 	sysctl_createv(clog, 0, NULL, NULL,
   1465      1.54    atatat 		       CTLFLAG_PERMANENT,
   1466      1.56    atatat 		       CTLTYPE_INT, "nbigpipes",
   1467      1.56    atatat 		       SYSCTL_DESCR("Number of \"big\" pipes"),
   1468      1.47    atatat 		       NULL, 0, &nbigpipe, 0,
   1469      1.47    atatat 		       CTL_KERN, KERN_PIPE, KERN_PIPE_NBIGPIPES, CTL_EOL);
   1470      1.54    atatat 	sysctl_createv(clog, 0, NULL, NULL,
   1471      1.54    atatat 		       CTLFLAG_PERMANENT,
   1472      1.56    atatat 		       CTLTYPE_INT, "kvasize",
   1473      1.56    atatat 		       SYSCTL_DESCR("Amount of kernel memory consumed by pipe "
   1474      1.56    atatat 				    "buffers"),
   1475      1.47    atatat 		       NULL, 0, &amountpipekva, 0,
   1476      1.47    atatat 		       CTL_KERN, KERN_PIPE, KERN_PIPE_KVASIZE, CTL_EOL);
   1477       1.2  jdolecek }
   1478