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f-stack/freebsd/sys/filedesc.h

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)filedesc.h 8.1 (Berkeley) 6/2/93
* $FreeBSD$
*/
#ifndef _SYS_FILEDESC_H_
#define _SYS_FILEDESC_H_
#include <sys/caprights.h>
#include <sys/queue.h>
#include <sys/event.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/priority.h>
#include <sys/seqc.h>
#include <sys/sx.h>
#include <sys/_smr.h>
#include <sys/smr_types.h>
#include <machine/_limits.h>
struct filecaps {
cap_rights_t fc_rights; /* per-descriptor capability rights */
u_long *fc_ioctls; /* per-descriptor allowed ioctls */
int16_t fc_nioctls; /* fc_ioctls array size */
uint32_t fc_fcntls; /* per-descriptor allowed fcntls */
};
struct filedescent {
struct file *fde_file; /* file structure for open file */
struct filecaps fde_caps; /* per-descriptor rights */
uint8_t fde_flags; /* per-process open file flags */
seqc_t fde_seqc; /* keep file and caps in sync */
};
#define fde_rights fde_caps.fc_rights
#define fde_fcntls fde_caps.fc_fcntls
#define fde_ioctls fde_caps.fc_ioctls
#define fde_nioctls fde_caps.fc_nioctls
#define fde_change_size (offsetof(struct filedescent, fde_seqc))
struct fdescenttbl {
int fdt_nfiles; /* number of open files allocated */
struct filedescent fdt_ofiles[0]; /* open files */
};
#define fd_seqc(fdt, fd) (&(fdt)->fdt_ofiles[(fd)].fde_seqc)
/*
* This structure is used for the management of descriptors. It may be
* shared by multiple processes.
*/
#define NDSLOTTYPE u_long
/*
* This struct is copy-on-write and allocated from an SMR zone.
* All fields are constant after initialization apart from the reference count.
*
* Check pwd_* routines for usage.
*/
struct pwd {
volatile u_int pwd_refcount;
struct vnode *pwd_cdir; /* current directory */
struct vnode *pwd_rdir; /* root directory */
struct vnode *pwd_jdir; /* jail root directory */
};
typedef SMR_POINTER(struct pwd *) smrpwd_t;
struct pwddesc {
struct mtx pd_lock; /* protects members of this struct */
smrpwd_t pd_pwd; /* directories */
volatile u_int pd_refcount;
u_short pd_cmask; /* mask for file creation */
};
struct filedesc {
struct fdescenttbl *fd_files; /* open files table */
NDSLOTTYPE *fd_map; /* bitmap of free fds */
int fd_freefile; /* approx. next free file */
int fd_refcnt; /* thread reference count */
int fd_holdcnt; /* hold count on structure + mutex */
struct sx fd_sx; /* protects members of this struct */
struct kqlist fd_kqlist; /* list of kqueues on this filedesc */
int fd_holdleaderscount; /* block fdfree() for shared close() */
int fd_holdleaderswakeup; /* fdfree() needs wakeup */
};
/*
* Structure to keep track of (process leader, struct fildedesc) tuples.
* Each process has a pointer to such a structure when detailed tracking
* is needed, e.g., when rfork(RFPROC | RFMEM) causes a file descriptor
* table to be shared by processes having different "p_leader" pointers
* and thus distinct POSIX style locks.
*
* fdl_refcount and fdl_holdcount are protected by struct filedesc mtx.
*/
struct filedesc_to_leader {
int fdl_refcount; /* references from struct proc */
int fdl_holdcount; /* temporary hold during closef */
int fdl_wakeup; /* fdfree() waits on closef() */
struct proc *fdl_leader; /* owner of POSIX locks */
/* Circular list: */
struct filedesc_to_leader *fdl_prev;
struct filedesc_to_leader *fdl_next;
};
#define fd_nfiles fd_files->fdt_nfiles
#define fd_ofiles fd_files->fdt_ofiles
/*
* Per-process open flags.
*/
#define UF_EXCLOSE 0x01 /* auto-close on exec */
#ifdef _KERNEL
/* Lock a paths descriptor table. */
#define PWDDESC_LOCK(pdp) (&(pdp)->pd_lock)
#define PWDDESC_LOCK_INIT(pdp) \
mtx_init(PWDDESC_LOCK(pdp), "pwddesc", NULL, MTX_DEF)
#define PWDDESC_LOCK_DESTROY(pdp) mtx_destroy(PWDDESC_LOCK(pdp))
#define PWDDESC_XLOCK(pdp) mtx_lock(PWDDESC_LOCK(pdp))
#define PWDDESC_XUNLOCK(pdp) mtx_unlock(PWDDESC_LOCK(pdp))
#define PWDDESC_LOCK_ASSERT(pdp, what) \
mtx_assert(PWDDESC_LOCK(pdp), (what))
#define PWDDESC_ASSERT_XLOCKED(pdp) \
PWDDESC_LOCK_ASSERT((pdp), MA_OWNED)
#define PWDDESC_ASSERT_UNLOCKED(pdp) \
PWDDESC_LOCK_ASSERT((pdp), MA_NOTOWNED)
#define PWDDESC_XLOCKED_LOAD_PWD(pdp) ({ \
struct pwddesc *_pdp = (pdp); \
struct pwd *_pwd; \
_pwd = smr_serialized_load(&(_pdp)->pd_pwd, \
(PWDDESC_ASSERT_XLOCKED(_pdp), true)); \
_pwd; \
})
/* Lock a file descriptor table. */
#define FILEDESC_LOCK_INIT(fdp) sx_init(&(fdp)->fd_sx, "filedesc structure")
#define FILEDESC_LOCK_DESTROY(fdp) sx_destroy(&(fdp)->fd_sx)
#define FILEDESC_LOCK(fdp) (&(fdp)->fd_sx)
#define FILEDESC_XLOCK(fdp) sx_xlock(&(fdp)->fd_sx)
#define FILEDESC_XUNLOCK(fdp) sx_xunlock(&(fdp)->fd_sx)
#define FILEDESC_SLOCK(fdp) sx_slock(&(fdp)->fd_sx)
#define FILEDESC_SUNLOCK(fdp) sx_sunlock(&(fdp)->fd_sx)
#define FILEDESC_LOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_LOCKED | \
SX_NOTRECURSED)
#define FILEDESC_XLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_XLOCKED | \
SX_NOTRECURSED)
#define FILEDESC_UNLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_UNLOCKED)
#define FILEDESC_IS_ONLY_USER(fdp) ({ \
struct filedesc *_fdp = (fdp); \
MPASS(curproc->p_fd == _fdp); \
(curproc->p_numthreads == 1 && refcount_load(&_fdp->fd_refcnt) == 1); \
})
#else
/*
* Accessor for libkvm et al.
*/
#define PWDDESC_KVM_LOAD_PWD(pdp) ({ \
struct pwddesc *_pdp = (pdp); \
struct pwd *_pwd; \
_pwd = smr_kvm_load(&(_pdp)->pd_pwd); \
_pwd; \
})
#endif
#ifdef _KERNEL
/* Operation types for kern_dup(). */
enum {
FDDUP_NORMAL, /* dup() behavior. */
FDDUP_FCNTL, /* fcntl()-style errors. */
FDDUP_FIXED, /* Force fixed allocation. */
FDDUP_MUSTREPLACE, /* Target must exist. */
FDDUP_LASTMODE,
};
/* Flags for kern_dup(). */
#define FDDUP_FLAG_CLOEXEC 0x1 /* Atomically set UF_EXCLOSE. */
/* For backward compatibility. */
#define falloc(td, resultfp, resultfd, flags) \
falloc_caps(td, resultfp, resultfd, flags, NULL)
struct thread;
static __inline void
filecaps_init(struct filecaps *fcaps)
{
bzero(fcaps, sizeof(*fcaps));
fcaps->fc_nioctls = -1;
}
bool filecaps_copy(const struct filecaps *src, struct filecaps *dst,
bool locked);
void filecaps_move(struct filecaps *src, struct filecaps *dst);
void filecaps_free(struct filecaps *fcaps);
int closef(struct file *fp, struct thread *td);
void closef_nothread(struct file *fp);
int dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode,
int openerror, int *indxp);
int falloc_caps(struct thread *td, struct file **resultfp, int *resultfd,
int flags, struct filecaps *fcaps);
void falloc_abort(struct thread *td, struct file *fp);
int _falloc_noinstall(struct thread *td, struct file **resultfp, u_int n);
#define falloc_noinstall(td, resultfp) _falloc_noinstall(td, resultfp, 1)
void _finstall(struct filedesc *fdp, struct file *fp, int fd, int flags,
struct filecaps *fcaps);
int finstall(struct thread *td, struct file *fp, int *resultfd, int flags,
struct filecaps *fcaps);
int finstall_refed(struct thread *td, struct file *fp, int *resultfd, int flags,
struct filecaps *fcaps);
int fdalloc(struct thread *td, int minfd, int *result);
int fdallocn(struct thread *td, int minfd, int *fds, int n);
int fdcheckstd(struct thread *td);
void fdclose(struct thread *td, struct file *fp, int idx);
void fdcloseexec(struct thread *td);
void fdsetugidsafety(struct thread *td);
struct filedesc *fdcopy(struct filedesc *fdp);
int fdcopy_remapped(struct filedesc *fdp, const int *fds, size_t nfds,
struct filedesc **newfdp);
void fdinstall_remapped(struct thread *td, struct filedesc *fdp);
void fdunshare(struct thread *td);
void fdescfree(struct thread *td);
void fdescfree_remapped(struct filedesc *fdp);
int fdlastfile(struct filedesc *fdp);
int fdlastfile_single(struct filedesc *fdp);
struct filedesc *fdinit(struct filedesc *fdp, bool prepfiles, int *lastfile);
struct filedesc *fdshare(struct filedesc *fdp);
struct filedesc_to_leader *
filedesc_to_leader_alloc(struct filedesc_to_leader *old,
struct filedesc *fdp, struct proc *leader);
int getvnode(struct thread *td, int fd, cap_rights_t *rightsp,
struct file **fpp);
void mountcheckdirs(struct vnode *olddp, struct vnode *newdp);
int fget_cap_locked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,
struct file **fpp, struct filecaps *havecapsp);
int fget_cap(struct thread *td, int fd, cap_rights_t *needrightsp,
struct file **fpp, struct filecaps *havecapsp);
/* Return a referenced file from an unlocked descriptor. */
int fget_unlocked_seq(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,
struct file **fpp, seqc_t *seqp);
int fget_unlocked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,
struct file **fpp);
/* Return a file pointer without a ref. FILEDESC_IS_ONLY_USER must be true. */
int fget_only_user(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,
struct file **fpp);
#define fput_only_user(fdp, fp) ({ \
MPASS(FILEDESC_IS_ONLY_USER(fdp)); \
MPASS(refcount_load(&fp->f_count) > 0); \
})
/* Requires a FILEDESC_{S,X}LOCK held and returns without a ref. */
static __inline struct file *
fget_locked(struct filedesc *fdp, int fd)
{
FILEDESC_LOCK_ASSERT(fdp);
if (__predict_false((u_int)fd >= fdp->fd_nfiles))
return (NULL);
return (fdp->fd_ofiles[fd].fde_file);
}
static __inline struct filedescent *
fdeget_locked(struct filedesc *fdp, int fd)
{
struct filedescent *fde;
FILEDESC_LOCK_ASSERT(fdp);
if (__predict_false((u_int)fd >= fdp->fd_nfiles))
return (NULL);
fde = &fdp->fd_ofiles[fd];
if (__predict_false(fde->fde_file == NULL))
return (NULL);
return (fde);
}
#ifdef CAPABILITIES
static __inline bool
fd_modified(struct filedesc *fdp, int fd, seqc_t seqc)
{
return (!seqc_consistent(fd_seqc(fdp->fd_files, fd), seqc));
}
#endif
/* cdir/rdir/jdir manipulation functions. */
struct pwddesc *pdcopy(struct pwddesc *pdp);
void pdescfree(struct thread *td);
struct pwddesc *pdinit(struct pwddesc *pdp, bool keeplock);
struct pwddesc *pdshare(struct pwddesc *pdp);
void pdunshare(struct thread *td);
void pwd_chdir(struct thread *td, struct vnode *vp);
int pwd_chroot(struct thread *td, struct vnode *vp);
int pwd_chroot_chdir(struct thread *td, struct vnode *vp);
void pwd_ensure_dirs(void);
void pwd_set_rootvnode(void);
struct pwd *pwd_hold_pwddesc(struct pwddesc *pdp);
bool pwd_hold_smr(struct pwd *pwd);
struct pwd *pwd_hold(struct thread *td);
void pwd_drop(struct pwd *pwd);
static inline void
pwd_set(struct pwddesc *pdp, struct pwd *newpwd)
{
smr_serialized_store(&pdp->pd_pwd, newpwd,
(PWDDESC_ASSERT_XLOCKED(pdp), true));
}
#define pwd_get_smr() vfs_smr_entered_load(&curproc->p_pd->pd_pwd)
#endif /* _KERNEL */
#endif /* !_SYS_FILEDESC_H_ */
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