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Supply unique (st_dev, st_ino) value pair for the fstat(2) done on the pipes.

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Reviewed by:	jhb, Peter Jeremy <peterjeremy acm org>
MFC after:	2 weeks
This commit is contained in:
kib 2011-10-05 16:56:06 +00:00
parent 12b63c734f
commit 87f923aeea
2 changed files with 27 additions and 2 deletions
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28
sys/kern/sys_pipe.c
View File

@ -93,6 +93,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/filedesc.h>
@ -224,6 +225,8 @@ static int pipe_zone_init(void *mem, int size, int flags);
static void pipe_zone_fini(void *mem, int size);
static uma_zone_t pipe_zone;
static struct unrhdr *pipeino_unr;
static dev_t pipedev_ino;
SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_ANY, pipeinit, NULL);
@ -235,6 +238,10 @@ pipeinit(void *dummy __unused)
pipe_zone_ctor, NULL, pipe_zone_init, pipe_zone_fini,
UMA_ALIGN_PTR, 0);
KASSERT(pipe_zone != NULL, ("pipe_zone not initialized"));
pipeino_unr = new_unrhdr(1, INT32_MAX, NULL);
KASSERT(pipeino_unr != NULL, ("pipe fake inodes not initialized"));
pipedev_ino = devfs_alloc_cdp_inode();
KASSERT(pipedev_ino > 0, ("pipe dev inode not initialized"));
}
static int
@ -562,6 +569,12 @@ pipe_create(pipe, backing)
/* If we're not backing this pipe, no need to do anything. */
error = 0;
}
if (error == 0) {
pipe->pipe_ino = alloc_unr(pipeino_unr);
if (pipe->pipe_ino == -1)
/* pipeclose will clear allocated kva */
error = ENOMEM;
}
return (error);
}
@ -1408,9 +1421,10 @@ pipe_stat(fp, ub, active_cred, td)
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_dev, st_ino, st_nlink, st_rdev, st_flags, st_gen.
* XXX (st_dev, st_ino) should be unique.
* Left as 0: st_nlink, st_rdev, st_flags, st_gen.
*/
return (0);
}
@ -1463,6 +1477,7 @@ pipeclose(cpipe)
{
struct pipepair *pp;
struct pipe *ppipe;
ino_t ino;
KASSERT(cpipe != NULL, ("pipeclose: cpipe == NULL"));
@ -1520,6 +1535,12 @@ pipeclose(cpipe)
seldrain(&cpipe->pipe_sel);
knlist_destroy(&cpipe->pipe_sel.si_note);
/*
* Postpone the destroy of the fake inode number allocated for
* our end, until pipe mtx is unlocked.
*/
ino = cpipe->pipe_ino;
/*
* If both endpoints are now closed, release the memory for the
* pipe pair. If not, unlock.
@ -1532,6 +1553,9 @@ pipeclose(cpipe)
uma_zfree(pipe_zone, cpipe->pipe_pair);
} else
PIPE_UNLOCK(cpipe);
if (ino > 0)
free_unr(pipeino_unr, cpipe->pipe_ino);
}
/*ARGSUSED*/

1
sys/sys/pipe.h
View File

@ -112,6 +112,7 @@ struct pipe {
u_int pipe_state; /* pipe status info */
int pipe_busy; /* busy flag, mostly to handle rundown sanely */
int pipe_present; /* still present? */
ino_t pipe_ino; /* fake inode for stat(2) */
};
/*