Date: Sun, 6 Jul 2014 22:47:18 +0000 (UTC) From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r268335 - in stable/10/sys: fs/fifofs kern sys Message-ID: <201407062247.s66MlI8e068689@svn.freebsd.org>
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Author: mjg Date: Sun Jul 6 22:47:18 2014 New Revision: 268335 URL: http://svnweb.freebsd.org/changeset/base/268335 Log: MFC r265206: Ignore the error from pipespace_new when creating a pipe. It can fail if pipe map is exhausted (as a result of too many pipes created), but it is not fatal and could be provoked by unprivileged users. The only consequence is worse performance with given pipe. Modified: stable/10/sys/fs/fifofs/fifo_vnops.c stable/10/sys/kern/sys_pipe.c stable/10/sys/sys/pipe.h Modified: stable/10/sys/fs/fifofs/fifo_vnops.c ============================================================================== --- stable/10/sys/fs/fifofs/fifo_vnops.c Sun Jul 6 22:09:50 2014 (r268334) +++ stable/10/sys/fs/fifofs/fifo_vnops.c Sun Jul 6 22:47:18 2014 (r268335) @@ -146,9 +146,7 @@ fifo_open(ap) if (fp == NULL || (ap->a_mode & FEXEC) != 0) return (EINVAL); if ((fip = vp->v_fifoinfo) == NULL) { - error = pipe_named_ctor(&fpipe, td); - if (error != 0) - return (error); + pipe_named_ctor(&fpipe, td); fip = malloc(sizeof(*fip), M_VNODE, M_WAITOK); fip->fi_pipe = fpipe; fpipe->pipe_wgen = fip->fi_readers = fip->fi_writers = 0; Modified: stable/10/sys/kern/sys_pipe.c ============================================================================== --- stable/10/sys/kern/sys_pipe.c Sun Jul 6 22:09:50 2014 (r268334) +++ stable/10/sys/kern/sys_pipe.c Sun Jul 6 22:47:18 2014 (r268335) @@ -221,8 +221,8 @@ SYSCTL_INT(_kern_ipc, OID_AUTO, piperesi static void pipeinit(void *dummy __unused); static void pipeclose(struct pipe *cpipe); static void pipe_free_kmem(struct pipe *cpipe); -static int pipe_create(struct pipe *pipe, int backing); -static int pipe_paircreate(struct thread *td, struct pipepair **p_pp); +static void pipe_create(struct pipe *pipe, int backing); +static void pipe_paircreate(struct thread *td, struct pipepair **p_pp); static __inline int pipelock(struct pipe *cpipe, int catch); static __inline void pipeunlock(struct pipe *cpipe); #ifndef PIPE_NODIRECT @@ -331,12 +331,11 @@ pipe_zone_fini(void *mem, int size) mtx_destroy(&pp->pp_mtx); } -static int +static void pipe_paircreate(struct thread *td, struct pipepair **p_pp) { struct pipepair *pp; struct pipe *rpipe, *wpipe; - int error; *p_pp = pp = uma_zalloc(pipe_zone, M_WAITOK); #ifdef MAC @@ -355,30 +354,21 @@ pipe_paircreate(struct thread *td, struc knlist_init_mtx(&wpipe->pipe_sel.si_note, PIPE_MTX(wpipe)); /* Only the forward direction pipe is backed by default */ - if ((error = pipe_create(rpipe, 1)) != 0 || - (error = pipe_create(wpipe, 0)) != 0) { - pipeclose(rpipe); - pipeclose(wpipe); - return (error); - } + pipe_create(rpipe, 1); + pipe_create(wpipe, 0); rpipe->pipe_state |= PIPE_DIRECTOK; wpipe->pipe_state |= PIPE_DIRECTOK; - return (0); } -int +void pipe_named_ctor(struct pipe **ppipe, struct thread *td) { struct pipepair *pp; - int error; - error = pipe_paircreate(td, &pp); - if (error != 0) - return (error); + pipe_paircreate(td, &pp); pp->pp_rpipe.pipe_state |= PIPE_NAMED; *ppipe = &pp->pp_rpipe; - return (0); } void @@ -419,9 +409,7 @@ kern_pipe2(struct thread *td, int fildes int fd, fflags, error; fdp = td->td_proc->p_fd; - error = pipe_paircreate(td, &pp); - if (error != 0) - return (error); + pipe_paircreate(td, &pp); rpipe = &pp->pp_rpipe; wpipe = &pp->pp_wpipe; error = falloc(td, &rf, &fd, flags); @@ -642,24 +630,27 @@ pipeselwakeup(cpipe) * 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 +static void pipe_create(pipe, backing) struct pipe *pipe; int backing; { - int error; if (backing) { + /* + * Note that these functions can fail if pipe map is exhausted + * (as a result of too many pipes created), but we ignore the + * error as it is not fatal and could be provoked by + * unprivileged users. The only consequence is worse performance + * with given pipe. + */ if (amountpipekva > maxpipekva / 2) - error = pipespace_new(pipe, SMALL_PIPE_SIZE); + (void)pipespace_new(pipe, SMALL_PIPE_SIZE); else - error = pipespace_new(pipe, PIPE_SIZE); - } else { - /* If we're not backing this pipe, no need to do anything. */ - error = 0; + (void)pipespace_new(pipe, PIPE_SIZE); } + pipe->pipe_ino = -1; - return (error); } /* ARGSUSED */ Modified: stable/10/sys/sys/pipe.h ============================================================================== --- stable/10/sys/sys/pipe.h Sun Jul 6 22:09:50 2014 (r268334) +++ stable/10/sys/sys/pipe.h Sun Jul 6 22:47:18 2014 (r268335) @@ -142,6 +142,6 @@ struct pipepair { #define PIPE_LOCK_ASSERT(pipe, type) mtx_assert(PIPE_MTX(pipe), (type)) void pipe_dtor(struct pipe *dpipe); -int pipe_named_ctor(struct pipe **ppipe, struct thread *td); +void pipe_named_ctor(struct pipe **ppipe, struct thread *td); void pipeselwakeup(struct pipe *cpipe); #endif /* !_SYS_PIPE_H_ */
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