/*- * 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 #include #include #include #include #include #include #include #include #include #include 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_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); void fdunshare(struct thread *td); void fdescfree(struct thread *td); 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); int getvnode_path(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_proc(struct proc *p); 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_ */