1866 lines
47 KiB
C
1866 lines
47 KiB
C
/*-
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* Copyright (c) 1996 John S. Dyson
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* Copyright (c) 2012 Giovanni Trematerra
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice immediately at the beginning of the file, without modification,
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* this list of conditions, and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Absolutely no warranty of function or purpose is made by the author
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* John S. Dyson.
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* 4. Modifications may be freely made to this file if the above conditions
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* are met.
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*/
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/*
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* This file contains a high-performance replacement for the socket-based
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* pipes scheme originally used in FreeBSD/4.4Lite. It does not support
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* all features of sockets, but does do everything that pipes normally
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* do.
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*/
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/*
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* This code has two modes of operation, a small write mode and a large
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* write mode. The small write mode acts like conventional pipes with
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* a kernel buffer. If the buffer is less than PIPE_MINDIRECT, then the
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* "normal" pipe buffering is done. If the buffer is between PIPE_MINDIRECT
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* and PIPE_SIZE in size, the sending process pins the underlying pages in
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* memory, and the receiving process copies directly from these pinned pages
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* in the sending process.
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*
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* If the sending process receives a signal, it is possible that it will
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* go away, and certainly its address space can change, because control
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* is returned back to the user-mode side. In that case, the pipe code
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* arranges to copy the buffer supplied by the user process, to a pageable
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* kernel buffer, and the receiving process will grab the data from the
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* pageable kernel buffer. Since signals don't happen all that often,
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* the copy operation is normally eliminated.
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*
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* The constant PIPE_MINDIRECT is chosen to make sure that buffering will
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* happen for small transfers so that the system will not spend all of
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* its time context switching.
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*
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* In order to limit the resource use of pipes, two sysctls exist:
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*
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* kern.ipc.maxpipekva - This is a hard limit on the amount of pageable
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* address space available to us in pipe_map. This value is normally
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* autotuned, but may also be loader tuned.
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*
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* kern.ipc.pipekva - This read-only sysctl tracks the current amount of
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* memory in use by pipes.
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*
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* Based on how large pipekva is relative to maxpipekva, the following
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* will happen:
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*
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* 0% - 50%:
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* New pipes are given 16K of memory backing, pipes may dynamically
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* grow to as large as 64K where needed.
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* 50% - 75%:
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* New pipes are given 4K (or PAGE_SIZE) of memory backing,
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* existing pipes may NOT grow.
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* 75% - 100%:
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* New pipes are given 4K (or PAGE_SIZE) of memory backing,
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* existing pipes will be shrunk down to 4K whenever possible.
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*
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* Resizing may be disabled by setting kern.ipc.piperesizeallowed=0. If
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* that is set, the only resize that will occur is the 0 -> SMALL_PIPE_SIZE
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* resize which MUST occur for reverse-direction pipes when they are
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* first used.
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*
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* Additional information about the current state of pipes may be obtained
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* from kern.ipc.pipes, kern.ipc.pipefragretry, kern.ipc.pipeallocfail,
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* and kern.ipc.piperesizefail.
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*
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* Locking rules: There are two locks present here: A mutex, used via
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* PIPE_LOCK, and a flag, used via pipelock(). All locking is done via
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* the flag, as mutexes can not persist over uiomove. The mutex
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* exists only to guard access to the flag, and is not in itself a
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* locking mechanism. Also note that there is only a single mutex for
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* both directions of a pipe.
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*
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* As pipelock() may have to sleep before it can acquire the flag, it
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* is important to reread all data after a call to pipelock(); everything
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* in the structure may have changed.
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*/
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#include <sys/cdefs.h>
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/conf.h>
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#include <sys/fcntl.h>
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#include <sys/file.h>
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#include <sys/filedesc.h>
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#include <sys/filio.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/ttycom.h>
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#include <sys/stat.h>
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#include <sys/malloc.h>
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#include <sys/poll.h>
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#include <sys/selinfo.h>
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#include <sys/signalvar.h>
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#include <sys/syscallsubr.h>
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#include <sys/sysctl.h>
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#include <sys/sysproto.h>
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#include <sys/pipe.h>
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#include <sys/proc.h>
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#include <sys/vnode.h>
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#include <sys/uio.h>
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#include <sys/user.h>
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#include <sys/event.h>
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#include <security/mac/mac_framework.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_object.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_extern.h>
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#include <vm/pmap.h>
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#include <vm/vm_map.h>
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#include <vm/vm_page.h>
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#include <vm/uma.h>
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/*
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* Use this define if you want to disable *fancy* VM things. Expect an
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* approx 30% decrease in transfer rate. This could be useful for
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* NetBSD or OpenBSD.
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*/
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/* #define PIPE_NODIRECT */
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#define PIPE_PEER(pipe) \
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(((pipe)->pipe_type & PIPE_TYPE_NAMED) ? (pipe) : ((pipe)->pipe_peer))
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/*
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* interfaces to the outside world
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*/
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static fo_rdwr_t pipe_read;
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static fo_rdwr_t pipe_write;
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static fo_truncate_t pipe_truncate;
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static fo_ioctl_t pipe_ioctl;
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static fo_poll_t pipe_poll;
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static fo_kqfilter_t pipe_kqfilter;
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static fo_stat_t pipe_stat;
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static fo_close_t pipe_close;
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static fo_chmod_t pipe_chmod;
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static fo_chown_t pipe_chown;
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static fo_fill_kinfo_t pipe_fill_kinfo;
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struct fileops pipeops = {
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.fo_read = pipe_read,
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.fo_write = pipe_write,
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.fo_truncate = pipe_truncate,
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.fo_ioctl = pipe_ioctl,
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.fo_poll = pipe_poll,
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.fo_kqfilter = pipe_kqfilter,
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.fo_stat = pipe_stat,
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.fo_close = pipe_close,
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.fo_chmod = pipe_chmod,
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.fo_chown = pipe_chown,
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.fo_sendfile = invfo_sendfile,
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.fo_fill_kinfo = pipe_fill_kinfo,
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.fo_flags = DFLAG_PASSABLE
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};
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static void filt_pipedetach(struct knote *kn);
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static void filt_pipedetach_notsup(struct knote *kn);
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static int filt_pipenotsup(struct knote *kn, long hint);
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static int filt_piperead(struct knote *kn, long hint);
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static int filt_pipewrite(struct knote *kn, long hint);
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static struct filterops pipe_nfiltops = {
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.f_isfd = 1,
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.f_detach = filt_pipedetach_notsup,
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.f_event = filt_pipenotsup
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};
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static struct filterops pipe_rfiltops = {
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.f_isfd = 1,
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.f_detach = filt_pipedetach,
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.f_event = filt_piperead
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};
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static struct filterops pipe_wfiltops = {
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.f_isfd = 1,
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.f_detach = filt_pipedetach,
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.f_event = filt_pipewrite
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};
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/*
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* Default pipe buffer size(s), this can be kind-of large now because pipe
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* space is pageable. The pipe code will try to maintain locality of
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* reference for performance reasons, so small amounts of outstanding I/O
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* will not wipe the cache.
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*/
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#define MINPIPESIZE (PIPE_SIZE/3)
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#define MAXPIPESIZE (2*PIPE_SIZE/3)
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static long amountpipekva;
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static int pipefragretry;
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static int pipeallocfail;
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static int piperesizefail;
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static int piperesizeallowed = 1;
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static long pipe_mindirect = PIPE_MINDIRECT;
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SYSCTL_LONG(_kern_ipc, OID_AUTO, maxpipekva, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
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&maxpipekva, 0, "Pipe KVA limit");
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SYSCTL_LONG(_kern_ipc, OID_AUTO, pipekva, CTLFLAG_RD,
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&amountpipekva, 0, "Pipe KVA usage");
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SYSCTL_INT(_kern_ipc, OID_AUTO, pipefragretry, CTLFLAG_RD,
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&pipefragretry, 0, "Pipe allocation retries due to fragmentation");
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SYSCTL_INT(_kern_ipc, OID_AUTO, pipeallocfail, CTLFLAG_RD,
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&pipeallocfail, 0, "Pipe allocation failures");
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SYSCTL_INT(_kern_ipc, OID_AUTO, piperesizefail, CTLFLAG_RD,
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&piperesizefail, 0, "Pipe resize failures");
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SYSCTL_INT(_kern_ipc, OID_AUTO, piperesizeallowed, CTLFLAG_RW,
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&piperesizeallowed, 0, "Pipe resizing allowed");
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static void pipeinit(void *dummy __unused);
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static void pipeclose(struct pipe *cpipe);
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static void pipe_free_kmem(struct pipe *cpipe);
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static int pipe_create(struct pipe *pipe, bool backing);
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static int pipe_paircreate(struct thread *td, struct pipepair **p_pp);
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static __inline int pipelock(struct pipe *cpipe, int catch);
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static __inline void pipeunlock(struct pipe *cpipe);
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static void pipe_timestamp(struct timespec *tsp);
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#ifndef PIPE_NODIRECT
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static int pipe_build_write_buffer(struct pipe *wpipe, struct uio *uio);
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static void pipe_destroy_write_buffer(struct pipe *wpipe);
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static int pipe_direct_write(struct pipe *wpipe, struct uio *uio);
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static void pipe_clone_write_buffer(struct pipe *wpipe);
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#endif
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static int pipespace(struct pipe *cpipe, int size);
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static int pipespace_new(struct pipe *cpipe, int size);
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static int pipe_zone_ctor(void *mem, int size, void *arg, int flags);
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static int pipe_zone_init(void *mem, int size, int flags);
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static void pipe_zone_fini(void *mem, int size);
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static uma_zone_t pipe_zone;
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static struct unrhdr64 pipeino_unr;
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static dev_t pipedev_ino;
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SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_ANY, pipeinit, NULL);
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static void
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pipeinit(void *dummy __unused)
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{
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pipe_zone = uma_zcreate("pipe", sizeof(struct pipepair),
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pipe_zone_ctor, NULL, pipe_zone_init, pipe_zone_fini,
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UMA_ALIGN_PTR, 0);
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KASSERT(pipe_zone != NULL, ("pipe_zone not initialized"));
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new_unrhdr64(&pipeino_unr, 1);
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pipedev_ino = devfs_alloc_cdp_inode();
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KASSERT(pipedev_ino > 0, ("pipe dev inode not initialized"));
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}
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static int
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sysctl_handle_pipe_mindirect(SYSCTL_HANDLER_ARGS)
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{
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int error = 0;
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long tmp_pipe_mindirect = pipe_mindirect;
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error = sysctl_handle_long(oidp, &tmp_pipe_mindirect, arg2, req);
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if (error != 0 || req->newptr == NULL)
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return (error);
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/*
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* Don't allow pipe_mindirect to be set so low that we violate
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* atomicity requirements.
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*/
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if (tmp_pipe_mindirect <= PIPE_BUF)
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return (EINVAL);
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pipe_mindirect = tmp_pipe_mindirect;
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return (0);
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}
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SYSCTL_OID(_kern_ipc, OID_AUTO, pipe_mindirect, CTLTYPE_LONG | CTLFLAG_RW,
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&pipe_mindirect, 0, sysctl_handle_pipe_mindirect, "L",
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"Minimum write size triggering VM optimization");
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static int
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pipe_zone_ctor(void *mem, int size, void *arg, int flags)
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{
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struct pipepair *pp;
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struct pipe *rpipe, *wpipe;
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KASSERT(size == sizeof(*pp), ("pipe_zone_ctor: wrong size"));
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pp = (struct pipepair *)mem;
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/*
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* We zero both pipe endpoints to make sure all the kmem pointers
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* are NULL, flag fields are zero'd, etc. We timestamp both
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* endpoints with the same time.
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*/
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rpipe = &pp->pp_rpipe;
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bzero(rpipe, sizeof(*rpipe));
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pipe_timestamp(&rpipe->pipe_ctime);
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rpipe->pipe_atime = rpipe->pipe_mtime = rpipe->pipe_ctime;
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wpipe = &pp->pp_wpipe;
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bzero(wpipe, sizeof(*wpipe));
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wpipe->pipe_ctime = rpipe->pipe_ctime;
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wpipe->pipe_atime = wpipe->pipe_mtime = rpipe->pipe_ctime;
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rpipe->pipe_peer = wpipe;
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rpipe->pipe_pair = pp;
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wpipe->pipe_peer = rpipe;
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wpipe->pipe_pair = pp;
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/*
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* Mark both endpoints as present; they will later get free'd
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* one at a time. When both are free'd, then the whole pair
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* is released.
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*/
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rpipe->pipe_present = PIPE_ACTIVE;
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wpipe->pipe_present = PIPE_ACTIVE;
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/*
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* Eventually, the MAC Framework may initialize the label
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* in ctor or init, but for now we do it elswhere to avoid
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* blocking in ctor or init.
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*/
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pp->pp_label = NULL;
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return (0);
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}
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static int
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pipe_zone_init(void *mem, int size, int flags)
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{
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struct pipepair *pp;
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KASSERT(size == sizeof(*pp), ("pipe_zone_init: wrong size"));
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pp = (struct pipepair *)mem;
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mtx_init(&pp->pp_mtx, "pipe mutex", NULL, MTX_DEF | MTX_NEW);
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return (0);
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}
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static void
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pipe_zone_fini(void *mem, int size)
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{
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struct pipepair *pp;
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KASSERT(size == sizeof(*pp), ("pipe_zone_fini: wrong size"));
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pp = (struct pipepair *)mem;
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mtx_destroy(&pp->pp_mtx);
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}
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|
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static int
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pipe_paircreate(struct thread *td, struct pipepair **p_pp)
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{
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struct pipepair *pp;
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struct pipe *rpipe, *wpipe;
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int error;
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|
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*p_pp = pp = uma_zalloc(pipe_zone, M_WAITOK);
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#ifdef MAC
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/*
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* The MAC label is shared between the connected endpoints. As a
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* result mac_pipe_init() and mac_pipe_create() are called once
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* for the pair, and not on the endpoints.
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*/
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mac_pipe_init(pp);
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mac_pipe_create(td->td_ucred, pp);
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#endif
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rpipe = &pp->pp_rpipe;
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wpipe = &pp->pp_wpipe;
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knlist_init_mtx(&rpipe->pipe_sel.si_note, PIPE_MTX(rpipe));
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knlist_init_mtx(&wpipe->pipe_sel.si_note, PIPE_MTX(wpipe));
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|
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/*
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* Only the forward direction pipe is backed by big buffer by
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* default.
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*/
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error = pipe_create(rpipe, true);
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if (error != 0)
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goto fail;
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error = pipe_create(wpipe, false);
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if (error != 0) {
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/*
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* This cleanup leaves the pipe inode number for rpipe
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* still allocated, but never used. We do not free
|
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* inode numbers for opened pipes, which is required
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* for correctness because numbers must be unique.
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* But also it avoids any memory use by the unr
|
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* allocator, so stashing away the transient inode
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* number is reasonable.
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*/
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pipe_free_kmem(rpipe);
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goto fail;
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}
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|
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rpipe->pipe_state |= PIPE_DIRECTOK;
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wpipe->pipe_state |= PIPE_DIRECTOK;
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return (0);
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fail:
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knlist_destroy(&rpipe->pipe_sel.si_note);
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knlist_destroy(&wpipe->pipe_sel.si_note);
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#ifdef MAC
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mac_pipe_destroy(pp);
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#endif
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uma_zfree(pipe_zone, pp);
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return (error);
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}
|
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|
|
int
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pipe_named_ctor(struct pipe **ppipe, struct thread *td)
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{
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struct pipepair *pp;
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int error;
|
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|
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error = pipe_paircreate(td, &pp);
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if (error != 0)
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return (error);
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pp->pp_rpipe.pipe_type |= PIPE_TYPE_NAMED;
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*ppipe = &pp->pp_rpipe;
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return (0);
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}
|
|
|
|
void
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pipe_dtor(struct pipe *dpipe)
|
|
{
|
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struct pipe *peer;
|
|
|
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peer = (dpipe->pipe_type & PIPE_TYPE_NAMED) != 0 ? dpipe->pipe_peer : NULL;
|
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funsetown(&dpipe->pipe_sigio);
|
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pipeclose(dpipe);
|
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if (peer != NULL) {
|
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funsetown(&peer->pipe_sigio);
|
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pipeclose(peer);
|
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}
|
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}
|
|
|
|
/*
|
|
* Get a timestamp.
|
|
*
|
|
* This used to be vfs_timestamp but the higher precision is unnecessary and
|
|
* can very negatively affect performance in virtualized environments (e.g., on
|
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* vms running on amd64 when using the rdtscp instruction).
|
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*/
|
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static void
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pipe_timestamp(struct timespec *tsp)
|
|
{
|
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|
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getnanotime(tsp);
|
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}
|
|
|
|
/*
|
|
* The pipe system call for the DTYPE_PIPE type of pipes. If we fail, let
|
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* the zone pick up the pieces via pipeclose().
|
|
*/
|
|
int
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|
kern_pipe(struct thread *td, int fildes[2], int flags, struct filecaps *fcaps1,
|
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struct filecaps *fcaps2)
|
|
{
|
|
struct file *rf, *wf;
|
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struct pipe *rpipe, *wpipe;
|
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struct pipepair *pp;
|
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int fd, fflags, error;
|
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|
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error = pipe_paircreate(td, &pp);
|
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if (error != 0)
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return (error);
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rpipe = &pp->pp_rpipe;
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wpipe = &pp->pp_wpipe;
|
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error = falloc_caps(td, &rf, &fd, flags, fcaps1);
|
|
if (error) {
|
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pipeclose(rpipe);
|
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pipeclose(wpipe);
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return (error);
|
|
}
|
|
/* An extra reference on `rf' has been held for us by falloc_caps(). */
|
|
fildes[0] = fd;
|
|
|
|
fflags = FREAD | FWRITE;
|
|
if ((flags & O_NONBLOCK) != 0)
|
|
fflags |= FNONBLOCK;
|
|
|
|
/*
|
|
* Warning: once we've gotten past allocation of the fd for the
|
|
* read-side, we can only drop the read side via fdrop() in order
|
|
* to avoid races against processes which manage to dup() the read
|
|
* side while we are blocked trying to allocate the write side.
|
|
*/
|
|
finit(rf, fflags, DTYPE_PIPE, rpipe, &pipeops);
|
|
error = falloc_caps(td, &wf, &fd, flags, fcaps2);
|
|
if (error) {
|
|
fdclose(td, rf, fildes[0]);
|
|
fdrop(rf, td);
|
|
/* rpipe has been closed by fdrop(). */
|
|
pipeclose(wpipe);
|
|
return (error);
|
|
}
|
|
/* An extra reference on `wf' has been held for us by falloc_caps(). */
|
|
finit(wf, fflags, DTYPE_PIPE, wpipe, &pipeops);
|
|
fdrop(wf, td);
|
|
fildes[1] = fd;
|
|
fdrop(rf, td);
|
|
|
|
return (0);
|
|
}
|
|
|
|
#ifdef COMPAT_FREEBSD10
|
|
/* ARGSUSED */
|
|
int
|
|
freebsd10_pipe(struct thread *td, struct freebsd10_pipe_args *uap __unused)
|
|
{
|
|
int error;
|
|
int fildes[2];
|
|
|
|
error = kern_pipe(td, fildes, 0, NULL, NULL);
|
|
if (error)
|
|
return (error);
|
|
|
|
td->td_retval[0] = fildes[0];
|
|
td->td_retval[1] = fildes[1];
|
|
|
|
return (0);
|
|
}
|
|
#endif
|
|
|
|
int
|
|
sys_pipe2(struct thread *td, struct pipe2_args *uap)
|
|
{
|
|
int error, fildes[2];
|
|
|
|
if (uap->flags & ~(O_CLOEXEC | O_NONBLOCK))
|
|
return (EINVAL);
|
|
error = kern_pipe(td, fildes, uap->flags, NULL, NULL);
|
|
if (error)
|
|
return (error);
|
|
error = copyout(fildes, uap->fildes, 2 * sizeof(int));
|
|
if (error) {
|
|
(void)kern_close(td, fildes[0]);
|
|
(void)kern_close(td, fildes[1]);
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Allocate kva for pipe circular buffer, the space is pageable
|
|
* This routine will 'realloc' the size of a pipe safely, if it fails
|
|
* it will retain the old buffer.
|
|
* If it fails it will return ENOMEM.
|
|
*/
|
|
static int
|
|
pipespace_new(struct pipe *cpipe, int size)
|
|
{
|
|
caddr_t buffer;
|
|
int error, cnt, firstseg;
|
|
static int curfail = 0;
|
|
static struct timeval lastfail;
|
|
|
|
KASSERT(!mtx_owned(PIPE_MTX(cpipe)), ("pipespace: pipe mutex locked"));
|
|
KASSERT(!(cpipe->pipe_state & PIPE_DIRECTW),
|
|
("pipespace: resize of direct writes not allowed"));
|
|
retry:
|
|
cnt = cpipe->pipe_buffer.cnt;
|
|
if (cnt > size)
|
|
size = cnt;
|
|
|
|
size = round_page(size);
|
|
buffer = (caddr_t) vm_map_min(pipe_map);
|
|
|
|
error = vm_map_find(pipe_map, NULL, 0, (vm_offset_t *)&buffer, size, 0,
|
|
VMFS_ANY_SPACE, VM_PROT_RW, VM_PROT_RW, 0);
|
|
if (error != KERN_SUCCESS) {
|
|
if (cpipe->pipe_buffer.buffer == NULL &&
|
|
size > SMALL_PIPE_SIZE) {
|
|
size = SMALL_PIPE_SIZE;
|
|
pipefragretry++;
|
|
goto retry;
|
|
}
|
|
if (cpipe->pipe_buffer.buffer == NULL) {
|
|
pipeallocfail++;
|
|
if (ppsratecheck(&lastfail, &curfail, 1))
|
|
printf("kern.ipc.maxpipekva exceeded; see tuning(7)\n");
|
|
} else {
|
|
piperesizefail++;
|
|
}
|
|
return (ENOMEM);
|
|
}
|
|
|
|
/* copy data, then free old resources if we're resizing */
|
|
if (cnt > 0) {
|
|
if (cpipe->pipe_buffer.in <= cpipe->pipe_buffer.out) {
|
|
firstseg = cpipe->pipe_buffer.size - cpipe->pipe_buffer.out;
|
|
bcopy(&cpipe->pipe_buffer.buffer[cpipe->pipe_buffer.out],
|
|
buffer, firstseg);
|
|
if ((cnt - firstseg) > 0)
|
|
bcopy(cpipe->pipe_buffer.buffer, &buffer[firstseg],
|
|
cpipe->pipe_buffer.in);
|
|
} else {
|
|
bcopy(&cpipe->pipe_buffer.buffer[cpipe->pipe_buffer.out],
|
|
buffer, cnt);
|
|
}
|
|
}
|
|
pipe_free_kmem(cpipe);
|
|
cpipe->pipe_buffer.buffer = buffer;
|
|
cpipe->pipe_buffer.size = size;
|
|
cpipe->pipe_buffer.in = cnt;
|
|
cpipe->pipe_buffer.out = 0;
|
|
cpipe->pipe_buffer.cnt = cnt;
|
|
atomic_add_long(&amountpipekva, cpipe->pipe_buffer.size);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Wrapper for pipespace_new() that performs locking assertions.
|
|
*/
|
|
static int
|
|
pipespace(struct pipe *cpipe, int size)
|
|
{
|
|
|
|
KASSERT(cpipe->pipe_state & PIPE_LOCKFL,
|
|
("Unlocked pipe passed to pipespace"));
|
|
return (pipespace_new(cpipe, size));
|
|
}
|
|
|
|
/*
|
|
* lock a pipe for I/O, blocking other access
|
|
*/
|
|
static __inline int
|
|
pipelock(struct pipe *cpipe, int catch)
|
|
{
|
|
int error, prio;
|
|
|
|
PIPE_LOCK_ASSERT(cpipe, MA_OWNED);
|
|
|
|
prio = PRIBIO;
|
|
if (catch)
|
|
prio |= PCATCH;
|
|
while (cpipe->pipe_state & PIPE_LOCKFL) {
|
|
KASSERT(cpipe->pipe_waiters >= 0,
|
|
("%s: bad waiter count %d", __func__,
|
|
cpipe->pipe_waiters));
|
|
cpipe->pipe_waiters++;
|
|
error = msleep(&cpipe->pipe_waiters, PIPE_MTX(cpipe), prio,
|
|
"pipelk", 0);
|
|
cpipe->pipe_waiters--;
|
|
if (error != 0)
|
|
return (error);
|
|
}
|
|
cpipe->pipe_state |= PIPE_LOCKFL;
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* unlock a pipe I/O lock
|
|
*/
|
|
static __inline void
|
|
pipeunlock(struct pipe *cpipe)
|
|
{
|
|
|
|
PIPE_LOCK_ASSERT(cpipe, MA_OWNED);
|
|
KASSERT(cpipe->pipe_state & PIPE_LOCKFL,
|
|
("Unlocked pipe passed to pipeunlock"));
|
|
KASSERT(cpipe->pipe_waiters >= 0,
|
|
("%s: bad waiter count %d", __func__,
|
|
cpipe->pipe_waiters));
|
|
cpipe->pipe_state &= ~PIPE_LOCKFL;
|
|
if (cpipe->pipe_waiters > 0)
|
|
wakeup_one(&cpipe->pipe_waiters);
|
|
}
|
|
|
|
void
|
|
pipeselwakeup(struct pipe *cpipe)
|
|
{
|
|
|
|
PIPE_LOCK_ASSERT(cpipe, MA_OWNED);
|
|
if (cpipe->pipe_state & PIPE_SEL) {
|
|
selwakeuppri(&cpipe->pipe_sel, PSOCK);
|
|
if (!SEL_WAITING(&cpipe->pipe_sel))
|
|
cpipe->pipe_state &= ~PIPE_SEL;
|
|
}
|
|
if ((cpipe->pipe_state & PIPE_ASYNC) && cpipe->pipe_sigio)
|
|
pgsigio(&cpipe->pipe_sigio, SIGIO, 0);
|
|
KNOTE_LOCKED(&cpipe->pipe_sel.si_note, 0);
|
|
}
|
|
|
|
/*
|
|
* Initialize and allocate VM and memory for pipe. The structure
|
|
* will start out zero'd from the ctor, so we just manage the kmem.
|
|
*/
|
|
static int
|
|
pipe_create(struct pipe *pipe, bool large_backing)
|
|
{
|
|
int error;
|
|
|
|
error = pipespace_new(pipe, !large_backing || amountpipekva >
|
|
maxpipekva / 2 ? SMALL_PIPE_SIZE : PIPE_SIZE);
|
|
if (error == 0)
|
|
pipe->pipe_ino = alloc_unr64(&pipeino_unr);
|
|
return (error);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static int
|
|
pipe_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
|
|
int flags, struct thread *td)
|
|
{
|
|
struct pipe *rpipe;
|
|
int error;
|
|
int nread = 0;
|
|
int size;
|
|
|
|
rpipe = fp->f_data;
|
|
|
|
/*
|
|
* Try to avoid locking the pipe if we have nothing to do.
|
|
*
|
|
* There are programs which share one pipe amongst multiple processes
|
|
* and perform non-blocking reads in parallel, even if the pipe is
|
|
* empty. This in particular is the case with BSD make, which when
|
|
* spawned with a high -j number can find itself with over half of the
|
|
* calls failing to find anything.
|
|
*/
|
|
if ((fp->f_flag & FNONBLOCK) != 0 && !mac_pipe_check_read_enabled()) {
|
|
if (__predict_false(uio->uio_resid == 0))
|
|
return (0);
|
|
if ((atomic_load_short(&rpipe->pipe_state) & PIPE_EOF) == 0 &&
|
|
atomic_load_int(&rpipe->pipe_buffer.cnt) == 0 &&
|
|
atomic_load_int(&rpipe->pipe_pages.cnt) == 0)
|
|
return (EAGAIN);
|
|
}
|
|
|
|
PIPE_LOCK(rpipe);
|
|
++rpipe->pipe_busy;
|
|
error = pipelock(rpipe, 1);
|
|
if (error)
|
|
goto unlocked_error;
|
|
|
|
#ifdef MAC
|
|
error = mac_pipe_check_read(active_cred, rpipe->pipe_pair);
|
|
if (error)
|
|
goto locked_error;
|
|
#endif
|
|
if (amountpipekva > (3 * maxpipekva) / 4) {
|
|
if ((rpipe->pipe_state & PIPE_DIRECTW) == 0 &&
|
|
rpipe->pipe_buffer.size > SMALL_PIPE_SIZE &&
|
|
rpipe->pipe_buffer.cnt <= SMALL_PIPE_SIZE &&
|
|
piperesizeallowed == 1) {
|
|
PIPE_UNLOCK(rpipe);
|
|
pipespace(rpipe, SMALL_PIPE_SIZE);
|
|
PIPE_LOCK(rpipe);
|
|
}
|
|
}
|
|
|
|
while (uio->uio_resid) {
|
|
/*
|
|
* normal pipe buffer receive
|
|
*/
|
|
if (rpipe->pipe_buffer.cnt > 0) {
|
|
size = rpipe->pipe_buffer.size - rpipe->pipe_buffer.out;
|
|
if (size > rpipe->pipe_buffer.cnt)
|
|
size = rpipe->pipe_buffer.cnt;
|
|
if (size > uio->uio_resid)
|
|
size = uio->uio_resid;
|
|
|
|
PIPE_UNLOCK(rpipe);
|
|
error = uiomove(
|
|
&rpipe->pipe_buffer.buffer[rpipe->pipe_buffer.out],
|
|
size, uio);
|
|
PIPE_LOCK(rpipe);
|
|
if (error)
|
|
break;
|
|
|
|
rpipe->pipe_buffer.out += size;
|
|
if (rpipe->pipe_buffer.out >= rpipe->pipe_buffer.size)
|
|
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
|
|
* cache hit stats.
|
|
*/
|
|
if (rpipe->pipe_buffer.cnt == 0) {
|
|
rpipe->pipe_buffer.in = 0;
|
|
rpipe->pipe_buffer.out = 0;
|
|
}
|
|
nread += size;
|
|
#ifndef PIPE_NODIRECT
|
|
/*
|
|
* Direct copy, bypassing a kernel buffer.
|
|
*/
|
|
} else if ((size = rpipe->pipe_pages.cnt) != 0) {
|
|
if (size > uio->uio_resid)
|
|
size = (u_int) uio->uio_resid;
|
|
PIPE_UNLOCK(rpipe);
|
|
error = uiomove_fromphys(rpipe->pipe_pages.ms,
|
|
rpipe->pipe_pages.pos, size, uio);
|
|
PIPE_LOCK(rpipe);
|
|
if (error)
|
|
break;
|
|
nread += size;
|
|
rpipe->pipe_pages.pos += size;
|
|
rpipe->pipe_pages.cnt -= size;
|
|
if (rpipe->pipe_pages.cnt == 0) {
|
|
rpipe->pipe_state &= ~PIPE_WANTW;
|
|
wakeup(rpipe);
|
|
}
|
|
#endif
|
|
} else {
|
|
/*
|
|
* detect EOF condition
|
|
* read returns 0 on EOF, no need to set error
|
|
*/
|
|
if (rpipe->pipe_state & PIPE_EOF)
|
|
break;
|
|
|
|
/*
|
|
* If the "write-side" has been blocked, wake it up now.
|
|
*/
|
|
if (rpipe->pipe_state & PIPE_WANTW) {
|
|
rpipe->pipe_state &= ~PIPE_WANTW;
|
|
wakeup(rpipe);
|
|
}
|
|
|
|
/*
|
|
* Break if some data was read.
|
|
*/
|
|
if (nread > 0)
|
|
break;
|
|
|
|
/*
|
|
* Unlock the pipe buffer for our remaining processing.
|
|
* We will either break out with an error or we will
|
|
* sleep and relock to loop.
|
|
*/
|
|
pipeunlock(rpipe);
|
|
|
|
/*
|
|
* Handle non-blocking mode operation or
|
|
* wait for more data.
|
|
*/
|
|
if (fp->f_flag & FNONBLOCK) {
|
|
error = EAGAIN;
|
|
} else {
|
|
rpipe->pipe_state |= PIPE_WANTR;
|
|
if ((error = msleep(rpipe, PIPE_MTX(rpipe),
|
|
PRIBIO | PCATCH,
|
|
"piperd", 0)) == 0)
|
|
error = pipelock(rpipe, 1);
|
|
}
|
|
if (error)
|
|
goto unlocked_error;
|
|
}
|
|
}
|
|
#ifdef MAC
|
|
locked_error:
|
|
#endif
|
|
pipeunlock(rpipe);
|
|
|
|
/* XXX: should probably do this before getting any locks. */
|
|
if (error == 0)
|
|
pipe_timestamp(&rpipe->pipe_atime);
|
|
unlocked_error:
|
|
--rpipe->pipe_busy;
|
|
|
|
/*
|
|
* PIPE_WANT processing only makes sense if pipe_busy is 0.
|
|
*/
|
|
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) {
|
|
/*
|
|
* Handle write blocking hysteresis.
|
|
*/
|
|
if (rpipe->pipe_state & PIPE_WANTW) {
|
|
rpipe->pipe_state &= ~PIPE_WANTW;
|
|
wakeup(rpipe);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Only wake up writers if there was actually something read.
|
|
* Otherwise, when calling read(2) at EOF, a spurious wakeup occurs.
|
|
*/
|
|
if (nread > 0 &&
|
|
rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt >= PIPE_BUF)
|
|
pipeselwakeup(rpipe);
|
|
|
|
PIPE_UNLOCK(rpipe);
|
|
if (nread > 0)
|
|
td->td_ru.ru_msgrcv++;
|
|
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(struct pipe *wpipe, struct uio *uio)
|
|
{
|
|
u_int size;
|
|
int i;
|
|
|
|
PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
|
|
KASSERT((wpipe->pipe_state & PIPE_DIRECTW) == 0,
|
|
("%s: PIPE_DIRECTW set on %p", __func__, wpipe));
|
|
KASSERT(wpipe->pipe_pages.cnt == 0,
|
|
("%s: pipe map for %p contains residual data", __func__, wpipe));
|
|
|
|
if (uio->uio_iov->iov_len > wpipe->pipe_buffer.size)
|
|
size = wpipe->pipe_buffer.size;
|
|
else
|
|
size = uio->uio_iov->iov_len;
|
|
|
|
wpipe->pipe_state |= PIPE_DIRECTW;
|
|
PIPE_UNLOCK(wpipe);
|
|
i = vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map,
|
|
(vm_offset_t)uio->uio_iov->iov_base, size, VM_PROT_READ,
|
|
wpipe->pipe_pages.ms, PIPENPAGES);
|
|
PIPE_LOCK(wpipe);
|
|
if (i < 0) {
|
|
wpipe->pipe_state &= ~PIPE_DIRECTW;
|
|
return (EFAULT);
|
|
}
|
|
|
|
wpipe->pipe_pages.npages = i;
|
|
wpipe->pipe_pages.pos =
|
|
((vm_offset_t) uio->uio_iov->iov_base) & PAGE_MASK;
|
|
wpipe->pipe_pages.cnt = size;
|
|
|
|
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->uio_resid -= size;
|
|
uio->uio_offset += size;
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Unwire the process buffer.
|
|
*/
|
|
static void
|
|
pipe_destroy_write_buffer(struct pipe *wpipe)
|
|
{
|
|
|
|
PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
|
|
KASSERT((wpipe->pipe_state & PIPE_DIRECTW) != 0,
|
|
("%s: PIPE_DIRECTW not set on %p", __func__, wpipe));
|
|
KASSERT(wpipe->pipe_pages.cnt == 0,
|
|
("%s: pipe map for %p contains residual data", __func__, wpipe));
|
|
|
|
wpipe->pipe_state &= ~PIPE_DIRECTW;
|
|
vm_page_unhold_pages(wpipe->pipe_pages.ms, wpipe->pipe_pages.npages);
|
|
wpipe->pipe_pages.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(struct pipe *wpipe)
|
|
{
|
|
struct uio uio;
|
|
struct iovec iov;
|
|
int size;
|
|
int pos;
|
|
|
|
PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
|
|
KASSERT((wpipe->pipe_state & PIPE_DIRECTW) != 0,
|
|
("%s: PIPE_DIRECTW not set on %p", __func__, wpipe));
|
|
|
|
size = wpipe->pipe_pages.cnt;
|
|
pos = wpipe->pipe_pages.pos;
|
|
wpipe->pipe_pages.cnt = 0;
|
|
|
|
wpipe->pipe_buffer.in = size;
|
|
wpipe->pipe_buffer.out = 0;
|
|
wpipe->pipe_buffer.cnt = size;
|
|
|
|
PIPE_UNLOCK(wpipe);
|
|
iov.iov_base = wpipe->pipe_buffer.buffer;
|
|
iov.iov_len = size;
|
|
uio.uio_iov = &iov;
|
|
uio.uio_iovcnt = 1;
|
|
uio.uio_offset = 0;
|
|
uio.uio_resid = size;
|
|
uio.uio_segflg = UIO_SYSSPACE;
|
|
uio.uio_rw = UIO_READ;
|
|
uio.uio_td = curthread;
|
|
uiomove_fromphys(wpipe->pipe_pages.ms, pos, size, &uio);
|
|
PIPE_LOCK(wpipe);
|
|
pipe_destroy_write_buffer(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.
|
|
*/
|
|
static int
|
|
pipe_direct_write(struct pipe *wpipe, struct uio *uio)
|
|
{
|
|
int error;
|
|
|
|
retry:
|
|
PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
|
|
if ((wpipe->pipe_state & PIPE_EOF) != 0) {
|
|
error = EPIPE;
|
|
goto error1;
|
|
}
|
|
if (wpipe->pipe_state & PIPE_DIRECTW) {
|
|
if (wpipe->pipe_state & PIPE_WANTR) {
|
|
wpipe->pipe_state &= ~PIPE_WANTR;
|
|
wakeup(wpipe);
|
|
}
|
|
pipeselwakeup(wpipe);
|
|
wpipe->pipe_state |= PIPE_WANTW;
|
|
pipeunlock(wpipe);
|
|
error = msleep(wpipe, PIPE_MTX(wpipe),
|
|
PRIBIO | PCATCH, "pipdww", 0);
|
|
pipelock(wpipe, 0);
|
|
if (error != 0)
|
|
goto error1;
|
|
goto retry;
|
|
}
|
|
if (wpipe->pipe_buffer.cnt > 0) {
|
|
if (wpipe->pipe_state & PIPE_WANTR) {
|
|
wpipe->pipe_state &= ~PIPE_WANTR;
|
|
wakeup(wpipe);
|
|
}
|
|
pipeselwakeup(wpipe);
|
|
wpipe->pipe_state |= PIPE_WANTW;
|
|
pipeunlock(wpipe);
|
|
error = msleep(wpipe, PIPE_MTX(wpipe),
|
|
PRIBIO | PCATCH, "pipdwc", 0);
|
|
pipelock(wpipe, 0);
|
|
if (error != 0)
|
|
goto error1;
|
|
goto retry;
|
|
}
|
|
|
|
error = pipe_build_write_buffer(wpipe, uio);
|
|
if (error) {
|
|
goto error1;
|
|
}
|
|
|
|
while (wpipe->pipe_pages.cnt != 0 &&
|
|
(wpipe->pipe_state & PIPE_EOF) == 0) {
|
|
if (wpipe->pipe_state & PIPE_WANTR) {
|
|
wpipe->pipe_state &= ~PIPE_WANTR;
|
|
wakeup(wpipe);
|
|
}
|
|
pipeselwakeup(wpipe);
|
|
wpipe->pipe_state |= PIPE_WANTW;
|
|
pipeunlock(wpipe);
|
|
error = msleep(wpipe, PIPE_MTX(wpipe), PRIBIO | PCATCH,
|
|
"pipdwt", 0);
|
|
pipelock(wpipe, 0);
|
|
if (error != 0)
|
|
break;
|
|
}
|
|
|
|
if ((wpipe->pipe_state & PIPE_EOF) != 0) {
|
|
wpipe->pipe_pages.cnt = 0;
|
|
pipe_destroy_write_buffer(wpipe);
|
|
pipeselwakeup(wpipe);
|
|
error = EPIPE;
|
|
} else if (error == EINTR || error == ERESTART) {
|
|
pipe_clone_write_buffer(wpipe);
|
|
} else {
|
|
pipe_destroy_write_buffer(wpipe);
|
|
}
|
|
KASSERT((wpipe->pipe_state & PIPE_DIRECTW) == 0,
|
|
("pipe %p leaked PIPE_DIRECTW", wpipe));
|
|
return (error);
|
|
|
|
error1:
|
|
wakeup(wpipe);
|
|
return (error);
|
|
}
|
|
#endif
|
|
|
|
static int
|
|
pipe_write(struct file *fp, struct uio *uio, struct ucred *active_cred,
|
|
int flags, struct thread *td)
|
|
{
|
|
struct pipe *wpipe, *rpipe;
|
|
ssize_t orig_resid;
|
|
int desiredsize, error;
|
|
|
|
rpipe = fp->f_data;
|
|
wpipe = PIPE_PEER(rpipe);
|
|
PIPE_LOCK(rpipe);
|
|
error = pipelock(wpipe, 1);
|
|
if (error) {
|
|
PIPE_UNLOCK(rpipe);
|
|
return (error);
|
|
}
|
|
/*
|
|
* detect loss of pipe read side, issue SIGPIPE if lost.
|
|
*/
|
|
if (wpipe->pipe_present != PIPE_ACTIVE ||
|
|
(wpipe->pipe_state & PIPE_EOF)) {
|
|
pipeunlock(wpipe);
|
|
PIPE_UNLOCK(rpipe);
|
|
return (EPIPE);
|
|
}
|
|
#ifdef MAC
|
|
error = mac_pipe_check_write(active_cred, wpipe->pipe_pair);
|
|
if (error) {
|
|
pipeunlock(wpipe);
|
|
PIPE_UNLOCK(rpipe);
|
|
return (error);
|
|
}
|
|
#endif
|
|
++wpipe->pipe_busy;
|
|
|
|
/* Choose a larger size if it's advantageous */
|
|
desiredsize = max(SMALL_PIPE_SIZE, wpipe->pipe_buffer.size);
|
|
while (desiredsize < wpipe->pipe_buffer.cnt + uio->uio_resid) {
|
|
if (piperesizeallowed != 1)
|
|
break;
|
|
if (amountpipekva > maxpipekva / 2)
|
|
break;
|
|
if (desiredsize == BIG_PIPE_SIZE)
|
|
break;
|
|
desiredsize = desiredsize * 2;
|
|
}
|
|
|
|
/* Choose a smaller size if we're in a OOM situation */
|
|
if (amountpipekva > (3 * maxpipekva) / 4 &&
|
|
wpipe->pipe_buffer.size > SMALL_PIPE_SIZE &&
|
|
wpipe->pipe_buffer.cnt <= SMALL_PIPE_SIZE &&
|
|
piperesizeallowed == 1)
|
|
desiredsize = SMALL_PIPE_SIZE;
|
|
|
|
/* Resize if the above determined that a new size was necessary */
|
|
if (desiredsize != wpipe->pipe_buffer.size &&
|
|
(wpipe->pipe_state & PIPE_DIRECTW) == 0) {
|
|
PIPE_UNLOCK(wpipe);
|
|
pipespace(wpipe, desiredsize);
|
|
PIPE_LOCK(wpipe);
|
|
}
|
|
MPASS(wpipe->pipe_buffer.size != 0);
|
|
|
|
orig_resid = uio->uio_resid;
|
|
|
|
while (uio->uio_resid) {
|
|
int space;
|
|
|
|
if (wpipe->pipe_state & PIPE_EOF) {
|
|
error = EPIPE;
|
|
break;
|
|
}
|
|
#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_segflg == UIO_USERSPACE &&
|
|
uio->uio_iov->iov_len >= pipe_mindirect &&
|
|
wpipe->pipe_buffer.size >= pipe_mindirect &&
|
|
(fp->f_flag & FNONBLOCK) == 0) {
|
|
error = pipe_direct_write(wpipe, uio);
|
|
if (error != 0)
|
|
break;
|
|
continue;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
if (wpipe->pipe_pages.cnt != 0) {
|
|
if (wpipe->pipe_state & PIPE_WANTR) {
|
|
wpipe->pipe_state &= ~PIPE_WANTR;
|
|
wakeup(wpipe);
|
|
}
|
|
pipeselwakeup(wpipe);
|
|
wpipe->pipe_state |= PIPE_WANTW;
|
|
pipeunlock(wpipe);
|
|
error = msleep(wpipe, PIPE_MTX(rpipe), PRIBIO | PCATCH,
|
|
"pipbww", 0);
|
|
pipelock(wpipe, 0);
|
|
if (error != 0)
|
|
break;
|
|
continue;
|
|
}
|
|
|
|
space = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt;
|
|
|
|
/* Writes of size <= PIPE_BUF must be atomic. */
|
|
if ((space < uio->uio_resid) && (orig_resid <= PIPE_BUF))
|
|
space = 0;
|
|
|
|
if (space > 0) {
|
|
int size; /* Transfer size */
|
|
int segsize; /* first segment to transfer */
|
|
|
|
/*
|
|
* Transfer size is minimum of uio transfer
|
|
* and free space in pipe buffer.
|
|
*/
|
|
if (space > uio->uio_resid)
|
|
size = uio->uio_resid;
|
|
else
|
|
size = space;
|
|
/*
|
|
* First segment to transfer is minimum of
|
|
* transfer size and contiguous space in
|
|
* pipe buffer. If first segment to transfer
|
|
* is less than the transfer size, we've got
|
|
* a wraparound in the buffer.
|
|
*/
|
|
segsize = wpipe->pipe_buffer.size -
|
|
wpipe->pipe_buffer.in;
|
|
if (segsize > size)
|
|
segsize = size;
|
|
|
|
/* Transfer first segment */
|
|
|
|
PIPE_UNLOCK(rpipe);
|
|
error = uiomove(&wpipe->pipe_buffer.buffer[wpipe->pipe_buffer.in],
|
|
segsize, uio);
|
|
PIPE_LOCK(rpipe);
|
|
|
|
if (error == 0 && segsize < size) {
|
|
KASSERT(wpipe->pipe_buffer.in + segsize ==
|
|
wpipe->pipe_buffer.size,
|
|
("Pipe buffer wraparound disappeared"));
|
|
/*
|
|
* Transfer remaining part now, to
|
|
* support atomic writes. Wraparound
|
|
* happened.
|
|
*/
|
|
|
|
PIPE_UNLOCK(rpipe);
|
|
error = uiomove(
|
|
&wpipe->pipe_buffer.buffer[0],
|
|
size - segsize, uio);
|
|
PIPE_LOCK(rpipe);
|
|
}
|
|
if (error == 0) {
|
|
wpipe->pipe_buffer.in += size;
|
|
if (wpipe->pipe_buffer.in >=
|
|
wpipe->pipe_buffer.size) {
|
|
KASSERT(wpipe->pipe_buffer.in ==
|
|
size - segsize +
|
|
wpipe->pipe_buffer.size,
|
|
("Expected wraparound bad"));
|
|
wpipe->pipe_buffer.in = size - segsize;
|
|
}
|
|
|
|
wpipe->pipe_buffer.cnt += size;
|
|
KASSERT(wpipe->pipe_buffer.cnt <=
|
|
wpipe->pipe_buffer.size,
|
|
("Pipe buffer overflow"));
|
|
}
|
|
if (error != 0)
|
|
break;
|
|
continue;
|
|
} else {
|
|
/*
|
|
* If the "read-side" has been blocked, wake it up now.
|
|
*/
|
|
if (wpipe->pipe_state & PIPE_WANTR) {
|
|
wpipe->pipe_state &= ~PIPE_WANTR;
|
|
wakeup(wpipe);
|
|
}
|
|
|
|
/*
|
|
* don't block on non-blocking I/O
|
|
*/
|
|
if (fp->f_flag & FNONBLOCK) {
|
|
error = EAGAIN;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* We have no more space and have something to offer,
|
|
* wake up select/poll.
|
|
*/
|
|
pipeselwakeup(wpipe);
|
|
|
|
wpipe->pipe_state |= PIPE_WANTW;
|
|
pipeunlock(wpipe);
|
|
error = msleep(wpipe, PIPE_MTX(rpipe),
|
|
PRIBIO | PCATCH, "pipewr", 0);
|
|
pipelock(wpipe, 0);
|
|
if (error != 0)
|
|
break;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
--wpipe->pipe_busy;
|
|
|
|
if ((wpipe->pipe_busy == 0) && (wpipe->pipe_state & PIPE_WANT)) {
|
|
wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR);
|
|
wakeup(wpipe);
|
|
} else if (wpipe->pipe_buffer.cnt > 0) {
|
|
/*
|
|
* If we have put any characters in the buffer, we wake up
|
|
* the reader.
|
|
*/
|
|
if (wpipe->pipe_state & PIPE_WANTR) {
|
|
wpipe->pipe_state &= ~PIPE_WANTR;
|
|
wakeup(wpipe);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Don't return EPIPE if any byte was written.
|
|
* EINTR and other interrupts are handled by generic I/O layer.
|
|
* Do not pretend that I/O succeeded for obvious user error
|
|
* like EFAULT.
|
|
*/
|
|
if (uio->uio_resid != orig_resid && error == EPIPE)
|
|
error = 0;
|
|
|
|
if (error == 0)
|
|
pipe_timestamp(&wpipe->pipe_mtime);
|
|
|
|
/*
|
|
* We have something to offer,
|
|
* wake up select/poll.
|
|
*/
|
|
if (wpipe->pipe_buffer.cnt)
|
|
pipeselwakeup(wpipe);
|
|
|
|
pipeunlock(wpipe);
|
|
PIPE_UNLOCK(rpipe);
|
|
if (uio->uio_resid != orig_resid)
|
|
td->td_ru.ru_msgsnd++;
|
|
return (error);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static int
|
|
pipe_truncate(struct file *fp, off_t length, struct ucred *active_cred,
|
|
struct thread *td)
|
|
{
|
|
struct pipe *cpipe;
|
|
int error;
|
|
|
|
cpipe = fp->f_data;
|
|
if (cpipe->pipe_type & PIPE_TYPE_NAMED)
|
|
error = vnops.fo_truncate(fp, length, active_cred, td);
|
|
else
|
|
error = invfo_truncate(fp, length, active_cred, td);
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* we implement a very minimal set of ioctls for compatibility with sockets.
|
|
*/
|
|
static int
|
|
pipe_ioctl(struct file *fp, u_long cmd, void *data, struct ucred *active_cred,
|
|
struct thread *td)
|
|
{
|
|
struct pipe *mpipe = fp->f_data;
|
|
int error;
|
|
|
|
PIPE_LOCK(mpipe);
|
|
|
|
#ifdef MAC
|
|
error = mac_pipe_check_ioctl(active_cred, mpipe->pipe_pair, cmd, data);
|
|
if (error) {
|
|
PIPE_UNLOCK(mpipe);
|
|
return (error);
|
|
}
|
|
#endif
|
|
|
|
error = 0;
|
|
switch (cmd) {
|
|
case FIONBIO:
|
|
break;
|
|
|
|
case FIOASYNC:
|
|
if (*(int *)data) {
|
|
mpipe->pipe_state |= PIPE_ASYNC;
|
|
} else {
|
|
mpipe->pipe_state &= ~PIPE_ASYNC;
|
|
}
|
|
break;
|
|
|
|
case FIONREAD:
|
|
if (!(fp->f_flag & FREAD)) {
|
|
*(int *)data = 0;
|
|
PIPE_UNLOCK(mpipe);
|
|
return (0);
|
|
}
|
|
if (mpipe->pipe_pages.cnt != 0)
|
|
*(int *)data = mpipe->pipe_pages.cnt;
|
|
else
|
|
*(int *)data = mpipe->pipe_buffer.cnt;
|
|
break;
|
|
|
|
case FIOSETOWN:
|
|
PIPE_UNLOCK(mpipe);
|
|
error = fsetown(*(int *)data, &mpipe->pipe_sigio);
|
|
goto out_unlocked;
|
|
|
|
case FIOGETOWN:
|
|
*(int *)data = fgetown(&mpipe->pipe_sigio);
|
|
break;
|
|
|
|
/* This is deprecated, FIOSETOWN should be used instead. */
|
|
case TIOCSPGRP:
|
|
PIPE_UNLOCK(mpipe);
|
|
error = fsetown(-(*(int *)data), &mpipe->pipe_sigio);
|
|
goto out_unlocked;
|
|
|
|
/* This is deprecated, FIOGETOWN should be used instead. */
|
|
case TIOCGPGRP:
|
|
*(int *)data = -fgetown(&mpipe->pipe_sigio);
|
|
break;
|
|
|
|
default:
|
|
error = ENOTTY;
|
|
break;
|
|
}
|
|
PIPE_UNLOCK(mpipe);
|
|
out_unlocked:
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
pipe_poll(struct file *fp, int events, struct ucred *active_cred,
|
|
struct thread *td)
|
|
{
|
|
struct pipe *rpipe;
|
|
struct pipe *wpipe;
|
|
int levents, revents;
|
|
#ifdef MAC
|
|
int error;
|
|
#endif
|
|
|
|
revents = 0;
|
|
rpipe = fp->f_data;
|
|
wpipe = PIPE_PEER(rpipe);
|
|
PIPE_LOCK(rpipe);
|
|
#ifdef MAC
|
|
error = mac_pipe_check_poll(active_cred, rpipe->pipe_pair);
|
|
if (error)
|
|
goto locked_error;
|
|
#endif
|
|
if (fp->f_flag & FREAD && events & (POLLIN | POLLRDNORM))
|
|
if (rpipe->pipe_pages.cnt > 0 || rpipe->pipe_buffer.cnt > 0)
|
|
revents |= events & (POLLIN | POLLRDNORM);
|
|
|
|
if (fp->f_flag & FWRITE && events & (POLLOUT | POLLWRNORM))
|
|
if (wpipe->pipe_present != PIPE_ACTIVE ||
|
|
(wpipe->pipe_state & PIPE_EOF) ||
|
|
((wpipe->pipe_state & PIPE_DIRECTW) == 0 &&
|
|
((wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF ||
|
|
wpipe->pipe_buffer.size == 0)))
|
|
revents |= events & (POLLOUT | POLLWRNORM);
|
|
|
|
levents = events &
|
|
(POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM | POLLRDBAND);
|
|
if (rpipe->pipe_type & PIPE_TYPE_NAMED && fp->f_flag & FREAD && levents &&
|
|
fp->f_pipegen == rpipe->pipe_wgen)
|
|
events |= POLLINIGNEOF;
|
|
|
|
if ((events & POLLINIGNEOF) == 0) {
|
|
if (rpipe->pipe_state & PIPE_EOF) {
|
|
if (fp->f_flag & FREAD)
|
|
revents |= (events & (POLLIN | POLLRDNORM));
|
|
if (wpipe->pipe_present != PIPE_ACTIVE ||
|
|
(wpipe->pipe_state & PIPE_EOF))
|
|
revents |= POLLHUP;
|
|
}
|
|
}
|
|
|
|
if (revents == 0) {
|
|
/*
|
|
* Add ourselves regardless of eventmask as we have to return
|
|
* POLLHUP even if it was not asked for.
|
|
*/
|
|
if ((fp->f_flag & FREAD) != 0) {
|
|
selrecord(td, &rpipe->pipe_sel);
|
|
if (SEL_WAITING(&rpipe->pipe_sel))
|
|
rpipe->pipe_state |= PIPE_SEL;
|
|
}
|
|
|
|
if ((fp->f_flag & FWRITE) != 0 &&
|
|
wpipe->pipe_present == PIPE_ACTIVE) {
|
|
selrecord(td, &wpipe->pipe_sel);
|
|
if (SEL_WAITING(&wpipe->pipe_sel))
|
|
wpipe->pipe_state |= PIPE_SEL;
|
|
}
|
|
}
|
|
#ifdef MAC
|
|
locked_error:
|
|
#endif
|
|
PIPE_UNLOCK(rpipe);
|
|
|
|
return (revents);
|
|
}
|
|
|
|
/*
|
|
* We shouldn't need locks here as we're doing a read and this should
|
|
* be a natural race.
|
|
*/
|
|
static int
|
|
pipe_stat(struct file *fp, struct stat *ub, struct ucred *active_cred)
|
|
{
|
|
struct pipe *pipe;
|
|
#ifdef MAC
|
|
int error;
|
|
#endif
|
|
|
|
pipe = fp->f_data;
|
|
#ifdef MAC
|
|
if (mac_pipe_check_stat_enabled()) {
|
|
PIPE_LOCK(pipe);
|
|
error = mac_pipe_check_stat(active_cred, pipe->pipe_pair);
|
|
PIPE_UNLOCK(pipe);
|
|
if (error) {
|
|
return (error);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* For named pipes ask the underlying filesystem. */
|
|
if (pipe->pipe_type & PIPE_TYPE_NAMED) {
|
|
return (vnops.fo_stat(fp, ub, active_cred));
|
|
}
|
|
|
|
bzero(ub, sizeof(*ub));
|
|
ub->st_mode = S_IFIFO;
|
|
ub->st_blksize = PAGE_SIZE;
|
|
if (pipe->pipe_pages.cnt != 0)
|
|
ub->st_size = pipe->pipe_pages.cnt;
|
|
else
|
|
ub->st_size = pipe->pipe_buffer.cnt;
|
|
ub->st_blocks = howmany(ub->st_size, ub->st_blksize);
|
|
ub->st_atim = pipe->pipe_atime;
|
|
ub->st_mtim = pipe->pipe_mtime;
|
|
ub->st_ctim = pipe->pipe_ctime;
|
|
ub->st_uid = fp->f_cred->cr_uid;
|
|
ub->st_gid = fp->f_cred->cr_gid;
|
|
ub->st_dev = pipedev_ino;
|
|
ub->st_ino = pipe->pipe_ino;
|
|
/*
|
|
* Left as 0: st_nlink, st_rdev, st_flags, st_gen.
|
|
*/
|
|
return (0);
|
|
}
|
|
|
|
/* ARGSUSED */
|
|
static int
|
|
pipe_close(struct file *fp, struct thread *td)
|
|
{
|
|
|
|
if (fp->f_vnode != NULL)
|
|
return vnops.fo_close(fp, td);
|
|
fp->f_ops = &badfileops;
|
|
pipe_dtor(fp->f_data);
|
|
fp->f_data = NULL;
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
pipe_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, struct thread *td)
|
|
{
|
|
struct pipe *cpipe;
|
|
int error;
|
|
|
|
cpipe = fp->f_data;
|
|
if (cpipe->pipe_type & PIPE_TYPE_NAMED)
|
|
error = vn_chmod(fp, mode, active_cred, td);
|
|
else
|
|
error = invfo_chmod(fp, mode, active_cred, td);
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
pipe_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
|
|
struct thread *td)
|
|
{
|
|
struct pipe *cpipe;
|
|
int error;
|
|
|
|
cpipe = fp->f_data;
|
|
if (cpipe->pipe_type & PIPE_TYPE_NAMED)
|
|
error = vn_chown(fp, uid, gid, active_cred, td);
|
|
else
|
|
error = invfo_chown(fp, uid, gid, active_cred, td);
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
pipe_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
|
|
{
|
|
struct pipe *pi;
|
|
|
|
if (fp->f_type == DTYPE_FIFO)
|
|
return (vn_fill_kinfo(fp, kif, fdp));
|
|
kif->kf_type = KF_TYPE_PIPE;
|
|
pi = fp->f_data;
|
|
kif->kf_un.kf_pipe.kf_pipe_addr = (uintptr_t)pi;
|
|
kif->kf_un.kf_pipe.kf_pipe_peer = (uintptr_t)pi->pipe_peer;
|
|
kif->kf_un.kf_pipe.kf_pipe_buffer_cnt = pi->pipe_buffer.cnt;
|
|
kif->kf_un.kf_pipe.kf_pipe_buffer_in = pi->pipe_buffer.in;
|
|
kif->kf_un.kf_pipe.kf_pipe_buffer_out = pi->pipe_buffer.out;
|
|
kif->kf_un.kf_pipe.kf_pipe_buffer_size = pi->pipe_buffer.size;
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
pipe_free_kmem(struct pipe *cpipe)
|
|
{
|
|
|
|
KASSERT(!mtx_owned(PIPE_MTX(cpipe)),
|
|
("pipe_free_kmem: pipe mutex locked"));
|
|
|
|
if (cpipe->pipe_buffer.buffer != NULL) {
|
|
atomic_subtract_long(&amountpipekva, cpipe->pipe_buffer.size);
|
|
vm_map_remove(pipe_map,
|
|
(vm_offset_t)cpipe->pipe_buffer.buffer,
|
|
(vm_offset_t)cpipe->pipe_buffer.buffer + cpipe->pipe_buffer.size);
|
|
cpipe->pipe_buffer.buffer = NULL;
|
|
}
|
|
#ifndef PIPE_NODIRECT
|
|
{
|
|
cpipe->pipe_pages.cnt = 0;
|
|
cpipe->pipe_pages.pos = 0;
|
|
cpipe->pipe_pages.npages = 0;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* shutdown the pipe
|
|
*/
|
|
static void
|
|
pipeclose(struct pipe *cpipe)
|
|
{
|
|
#ifdef MAC
|
|
struct pipepair *pp;
|
|
#endif
|
|
struct pipe *ppipe;
|
|
|
|
KASSERT(cpipe != NULL, ("pipeclose: cpipe == NULL"));
|
|
|
|
PIPE_LOCK(cpipe);
|
|
pipelock(cpipe, 0);
|
|
#ifdef MAC
|
|
pp = cpipe->pipe_pair;
|
|
#endif
|
|
|
|
/*
|
|
* If the other side is blocked, wake it up saying that
|
|
* we want to close it down.
|
|
*/
|
|
cpipe->pipe_state |= PIPE_EOF;
|
|
while (cpipe->pipe_busy) {
|
|
wakeup(cpipe);
|
|
cpipe->pipe_state |= PIPE_WANT;
|
|
pipeunlock(cpipe);
|
|
msleep(cpipe, PIPE_MTX(cpipe), PRIBIO, "pipecl", 0);
|
|
pipelock(cpipe, 0);
|
|
}
|
|
|
|
pipeselwakeup(cpipe);
|
|
|
|
/*
|
|
* Disconnect from peer, if any.
|
|
*/
|
|
ppipe = cpipe->pipe_peer;
|
|
if (ppipe->pipe_present == PIPE_ACTIVE) {
|
|
ppipe->pipe_state |= PIPE_EOF;
|
|
wakeup(ppipe);
|
|
pipeselwakeup(ppipe);
|
|
}
|
|
|
|
/*
|
|
* Mark this endpoint as free. Release kmem resources. We
|
|
* don't mark this endpoint as unused until we've finished
|
|
* doing that, or the pipe might disappear out from under
|
|
* us.
|
|
*/
|
|
PIPE_UNLOCK(cpipe);
|
|
pipe_free_kmem(cpipe);
|
|
PIPE_LOCK(cpipe);
|
|
cpipe->pipe_present = PIPE_CLOSING;
|
|
pipeunlock(cpipe);
|
|
|
|
/*
|
|
* knlist_clear() may sleep dropping the PIPE_MTX. Set the
|
|
* PIPE_FINALIZED, that allows other end to free the
|
|
* pipe_pair, only after the knotes are completely dismantled.
|
|
*/
|
|
knlist_clear(&cpipe->pipe_sel.si_note, 1);
|
|
cpipe->pipe_present = PIPE_FINALIZED;
|
|
seldrain(&cpipe->pipe_sel);
|
|
knlist_destroy(&cpipe->pipe_sel.si_note);
|
|
|
|
/*
|
|
* If both endpoints are now closed, release the memory for the
|
|
* pipe pair. If not, unlock.
|
|
*/
|
|
if (ppipe->pipe_present == PIPE_FINALIZED) {
|
|
PIPE_UNLOCK(cpipe);
|
|
#ifdef MAC
|
|
mac_pipe_destroy(pp);
|
|
#endif
|
|
uma_zfree(pipe_zone, cpipe->pipe_pair);
|
|
} else
|
|
PIPE_UNLOCK(cpipe);
|
|
}
|
|
|
|
/*ARGSUSED*/
|
|
static int
|
|
pipe_kqfilter(struct file *fp, struct knote *kn)
|
|
{
|
|
struct pipe *cpipe;
|
|
|
|
/*
|
|
* If a filter is requested that is not supported by this file
|
|
* descriptor, don't return an error, but also don't ever generate an
|
|
* event.
|
|
*/
|
|
if ((kn->kn_filter == EVFILT_READ) && !(fp->f_flag & FREAD)) {
|
|
kn->kn_fop = &pipe_nfiltops;
|
|
return (0);
|
|
}
|
|
if ((kn->kn_filter == EVFILT_WRITE) && !(fp->f_flag & FWRITE)) {
|
|
kn->kn_fop = &pipe_nfiltops;
|
|
return (0);
|
|
}
|
|
cpipe = fp->f_data;
|
|
PIPE_LOCK(cpipe);
|
|
switch (kn->kn_filter) {
|
|
case EVFILT_READ:
|
|
kn->kn_fop = &pipe_rfiltops;
|
|
break;
|
|
case EVFILT_WRITE:
|
|
kn->kn_fop = &pipe_wfiltops;
|
|
if (cpipe->pipe_peer->pipe_present != PIPE_ACTIVE) {
|
|
/* other end of pipe has been closed */
|
|
PIPE_UNLOCK(cpipe);
|
|
return (EPIPE);
|
|
}
|
|
cpipe = PIPE_PEER(cpipe);
|
|
break;
|
|
default:
|
|
if ((cpipe->pipe_type & PIPE_TYPE_NAMED) != 0) {
|
|
PIPE_UNLOCK(cpipe);
|
|
return (vnops.fo_kqfilter(fp, kn));
|
|
}
|
|
PIPE_UNLOCK(cpipe);
|
|
return (EINVAL);
|
|
}
|
|
|
|
kn->kn_hook = cpipe;
|
|
knlist_add(&cpipe->pipe_sel.si_note, kn, 1);
|
|
PIPE_UNLOCK(cpipe);
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
filt_pipedetach(struct knote *kn)
|
|
{
|
|
struct pipe *cpipe = kn->kn_hook;
|
|
|
|
PIPE_LOCK(cpipe);
|
|
knlist_remove(&cpipe->pipe_sel.si_note, kn, 1);
|
|
PIPE_UNLOCK(cpipe);
|
|
}
|
|
|
|
/*ARGSUSED*/
|
|
static int
|
|
filt_piperead(struct knote *kn, long hint)
|
|
{
|
|
struct file *fp = kn->kn_fp;
|
|
struct pipe *rpipe = kn->kn_hook;
|
|
|
|
PIPE_LOCK_ASSERT(rpipe, MA_OWNED);
|
|
kn->kn_data = rpipe->pipe_buffer.cnt;
|
|
if (kn->kn_data == 0)
|
|
kn->kn_data = rpipe->pipe_pages.cnt;
|
|
|
|
if ((rpipe->pipe_state & PIPE_EOF) != 0 &&
|
|
((rpipe->pipe_type & PIPE_TYPE_NAMED) == 0 ||
|
|
fp->f_pipegen != rpipe->pipe_wgen)) {
|
|
kn->kn_flags |= EV_EOF;
|
|
return (1);
|
|
}
|
|
kn->kn_flags &= ~EV_EOF;
|
|
return (kn->kn_data > 0);
|
|
}
|
|
|
|
/*ARGSUSED*/
|
|
static int
|
|
filt_pipewrite(struct knote *kn, long hint)
|
|
{
|
|
struct pipe *wpipe = kn->kn_hook;
|
|
|
|
/*
|
|
* If this end of the pipe is closed, the knote was removed from the
|
|
* knlist and the list lock (i.e., the pipe lock) is therefore not held.
|
|
*/
|
|
if (wpipe->pipe_present == PIPE_ACTIVE ||
|
|
(wpipe->pipe_type & PIPE_TYPE_NAMED) != 0) {
|
|
PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
|
|
|
|
if (wpipe->pipe_state & PIPE_DIRECTW) {
|
|
kn->kn_data = 0;
|
|
} else if (wpipe->pipe_buffer.size > 0) {
|
|
kn->kn_data = wpipe->pipe_buffer.size -
|
|
wpipe->pipe_buffer.cnt;
|
|
} else {
|
|
kn->kn_data = PIPE_BUF;
|
|
}
|
|
}
|
|
|
|
if (wpipe->pipe_present != PIPE_ACTIVE ||
|
|
(wpipe->pipe_state & PIPE_EOF)) {
|
|
kn->kn_flags |= EV_EOF;
|
|
return (1);
|
|
}
|
|
kn->kn_flags &= ~EV_EOF;
|
|
return (kn->kn_data >= PIPE_BUF);
|
|
}
|
|
|
|
static void
|
|
filt_pipedetach_notsup(struct knote *kn)
|
|
{
|
|
|
|
}
|
|
|
|
static int
|
|
filt_pipenotsup(struct knote *kn, long hint)
|
|
{
|
|
|
|
return (0);
|
|
}
|