1/*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32#ifndef _SYS_FILEDESC_H_ 33#define _SYS_FILEDESC_H_ 34 35#include <sys/types.h> 36#include <sys/caprights.h> 37#include <sys/queue.h> 38#include <sys/event.h> 39#include <sys/lock.h> 40#include <sys/mutex.h> 41#include <sys/priority.h> 42#include <sys/seqc.h> 43#include <sys/sx.h> 44#include <sys/_smr.h> 45#include <sys/smr_types.h> 46 47#include <machine/_limits.h> 48 49struct filecaps { 50 cap_rights_t fc_rights; /* per-descriptor capability rights */ 51 u_long *fc_ioctls; /* per-descriptor allowed ioctls */ 52 int16_t fc_nioctls; /* fc_ioctls array size */ 53 uint32_t fc_fcntls; /* per-descriptor allowed fcntls */ 54}; 55 56struct filedescent { 57 struct file *fde_file; /* file structure for open file */ 58 struct filecaps fde_caps; /* per-descriptor rights */ 59 uint8_t fde_flags; /* per-process open file flags */ 60 seqc_t fde_seqc; /* keep file and caps in sync */ 61}; 62#define fde_rights fde_caps.fc_rights 63#define fde_fcntls fde_caps.fc_fcntls 64#define fde_ioctls fde_caps.fc_ioctls 65#define fde_nioctls fde_caps.fc_nioctls 66 67#ifdef _KERNEL 68static inline void 69fde_copy(struct filedescent *from, struct filedescent *to) 70{ 71 72 to->fde_file = from->fde_file; 73 to->fde_caps = from->fde_caps; 74 to->fde_flags = from->fde_flags; 75} 76#endif 77 78struct fdescenttbl { 79 int fdt_nfiles; /* number of open files allocated */ 80 struct filedescent fdt_ofiles[0]; /* open files */ 81}; 82#define fd_seqc(fdt, fd) (&(fdt)->fdt_ofiles[(fd)].fde_seqc) 83 84#define NDSLOTTYPE u_long 85 86/* 87 * This struct is copy-on-write and allocated from an SMR zone. 88 * All fields are constant after initialization apart from the reference count. 89 * The ABI root directory is initialized as the root directory and changed 90 * during process transiting to or from non-native ABI. 91 * 92 * Check pwd_* routines for usage. 93 */ 94struct pwd { 95 u_int pwd_refcount; 96 struct vnode *pwd_cdir; /* current directory */ 97 struct vnode *pwd_rdir; /* root directory */ 98 struct vnode *pwd_jdir; /* jail root directory */ 99 struct vnode *pwd_adir; /* abi root directory */ 100}; 101typedef SMR_POINTER(struct pwd *) smrpwd_t; 102 103struct pwddesc { 104 struct mtx pd_lock; /* protects members of this struct */ 105 smrpwd_t pd_pwd; /* directories */ 106 u_int pd_refcount; 107 u_short pd_cmask; /* mask for file creation */ 108}; 109 110/* 111 * This structure is used for the management of descriptors. It may be 112 * shared by multiple processes. 113 */ 114struct filedesc { 115 struct fdescenttbl *fd_files; /* open files table */ 116 NDSLOTTYPE *fd_map; /* bitmap of free fds */ 117 int fd_freefile; /* approx. next free file */ 118 int fd_refcnt; /* thread reference count */ 119 int fd_holdcnt; /* hold count on structure + mutex */ 120 struct sx fd_sx; /* protects members of this struct */ 121 struct kqlist fd_kqlist; /* list of kqueues on this filedesc */ 122 int fd_holdleaderscount; /* block fdfree() for shared close() */ 123 int fd_holdleaderswakeup; /* fdfree() needs wakeup */ 124}; 125 126/* 127 * Structure to keep track of (process leader, struct fildedesc) tuples. 128 * Each process has a pointer to such a structure when detailed tracking 129 * is needed, e.g., when rfork(RFPROC | RFMEM) causes a file descriptor 130 * table to be shared by processes having different "p_leader" pointers 131 * and thus distinct POSIX style locks. 132 * 133 * fdl_refcount and fdl_holdcount are protected by struct filedesc mtx. 134 */ 135struct filedesc_to_leader { 136 int fdl_refcount; /* references from struct proc */ 137 int fdl_holdcount; /* temporary hold during closef */ 138 int fdl_wakeup; /* fdfree() waits on closef() */ 139 struct proc *fdl_leader; /* owner of POSIX locks */ 140 /* Circular list: */ 141 struct filedesc_to_leader *fdl_prev; 142 struct filedesc_to_leader *fdl_next; 143}; 144#define fd_nfiles fd_files->fdt_nfiles 145#define fd_ofiles fd_files->fdt_ofiles 146 147/* 148 * Per-process open flags. 149 */ 150#define UF_EXCLOSE 0x01 /* auto-close on exec */ 151 152#ifdef _KERNEL 153 154/* Lock a paths descriptor table. */ 155#define PWDDESC_LOCK(pdp) (&(pdp)->pd_lock) 156#define PWDDESC_LOCK_INIT(pdp) \ 157 mtx_init(PWDDESC_LOCK(pdp), "pwddesc", NULL, MTX_DEF) 158#define PWDDESC_LOCK_DESTROY(pdp) mtx_destroy(PWDDESC_LOCK(pdp)) 159#define PWDDESC_XLOCK(pdp) mtx_lock(PWDDESC_LOCK(pdp)) 160#define PWDDESC_XUNLOCK(pdp) mtx_unlock(PWDDESC_LOCK(pdp)) 161#define PWDDESC_LOCK_ASSERT(pdp, what) \ 162 mtx_assert(PWDDESC_LOCK(pdp), (what)) 163#define PWDDESC_ASSERT_XLOCKED(pdp) \ 164 PWDDESC_LOCK_ASSERT((pdp), MA_OWNED) 165#define PWDDESC_ASSERT_UNLOCKED(pdp) \ 166 PWDDESC_LOCK_ASSERT((pdp), MA_NOTOWNED) 167 168#define PWDDESC_XLOCKED_LOAD_PWD(pdp) ({ \ 169 struct pwddesc *_pdp = (pdp); \ 170 struct pwd *_pwd; \ 171 _pwd = smr_serialized_load(&(_pdp)->pd_pwd, \ 172 (PWDDESC_ASSERT_XLOCKED(_pdp), true)); \ 173 _pwd; \ 174}) 175 176/* Lock a file descriptor table. */ 177#define FILEDESC_LOCK_INIT(fdp) sx_init(&(fdp)->fd_sx, "filedesc structure") 178#define FILEDESC_LOCK_DESTROY(fdp) sx_destroy(&(fdp)->fd_sx) 179#define FILEDESC_LOCK(fdp) (&(fdp)->fd_sx) 180#define FILEDESC_XLOCK(fdp) sx_xlock(&(fdp)->fd_sx) 181#define FILEDESC_XUNLOCK(fdp) sx_xunlock(&(fdp)->fd_sx) 182#define FILEDESC_SLOCK(fdp) sx_slock(&(fdp)->fd_sx) 183#define FILEDESC_SUNLOCK(fdp) sx_sunlock(&(fdp)->fd_sx) 184 185#define FILEDESC_LOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_LOCKED | \ 186 SX_NOTRECURSED) 187#define FILEDESC_XLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_XLOCKED | \ 188 SX_NOTRECURSED) 189#define FILEDESC_UNLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_UNLOCKED) 190 191#define FILEDESC_IS_ONLY_USER(fdp) ({ \ 192 struct filedesc *_fdp = (fdp); \ 193 MPASS(curproc->p_fd == _fdp); \ 194 (curproc->p_numthreads == 1 && refcount_load(&_fdp->fd_refcnt) == 1); \ 195}) 196 197#else 198 199/* 200 * Accessor for libkvm et al. 201 */ 202#define PWDDESC_KVM_LOAD_PWD(pdp) ({ \ 203 struct pwddesc *_pdp = (pdp); \ 204 struct pwd *_pwd; \ 205 _pwd = smr_kvm_load(&(_pdp)->pd_pwd); \ 206 _pwd; \ 207}) 208 209#endif 210 211#ifdef _KERNEL 212 213/* Operation types for kern_dup(). */ 214enum { 215 FDDUP_NORMAL, /* dup() behavior. */ 216 FDDUP_FCNTL, /* fcntl()-style errors. */ 217 FDDUP_FIXED, /* Force fixed allocation. */ 218 FDDUP_LASTMODE, 219}; 220 221/* Flags for kern_dup(). */ 222#define FDDUP_FLAG_CLOEXEC 0x1 /* Atomically set UF_EXCLOSE. */ 223 224/* For backward compatibility. */ 225#define falloc(td, resultfp, resultfd, flags) \ 226 falloc_caps(td, resultfp, resultfd, flags, NULL) 227 228struct mount; 229struct thread; 230 231static __inline void 232filecaps_init(struct filecaps *fcaps) 233{ 234 235 bzero(fcaps, sizeof(*fcaps)); 236 fcaps->fc_nioctls = -1; 237} 238bool filecaps_copy(const struct filecaps *src, struct filecaps *dst, 239 bool locked); 240void filecaps_move(struct filecaps *src, struct filecaps *dst); 241void filecaps_free(struct filecaps *fcaps); 242 243int closef(struct file *fp, struct thread *td); 244void closef_nothread(struct file *fp); 245int descrip_check_write_mp(struct filedesc *fdp, struct mount *mp); 246int dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode, 247 int openerror, int *indxp); 248int falloc_caps(struct thread *td, struct file **resultfp, int *resultfd, 249 int flags, struct filecaps *fcaps); 250void falloc_abort(struct thread *td, struct file *fp); 251int _falloc_noinstall(struct thread *td, struct file **resultfp, u_int n); 252#define falloc_noinstall(td, resultfp) _falloc_noinstall(td, resultfp, 1) 253void _finstall(struct filedesc *fdp, struct file *fp, int fd, int flags, 254 struct filecaps *fcaps); 255int finstall(struct thread *td, struct file *fp, int *resultfd, int flags, 256 struct filecaps *fcaps); 257int finstall_refed(struct thread *td, struct file *fp, int *resultfd, int flags, 258 struct filecaps *fcaps); 259int fdalloc(struct thread *td, int minfd, int *result); 260int fdallocn(struct thread *td, int minfd, int *fds, int n); 261int fdcheckstd(struct thread *td); 262void fdclose(struct thread *td, struct file *fp, int idx); 263void fdcloseexec(struct thread *td); 264void fdsetugidsafety(struct thread *td); 265struct filedesc *fdcopy(struct filedesc *fdp); 266void fdunshare(struct thread *td); 267void fdescfree(struct thread *td); 268int fdlastfile(struct filedesc *fdp); 269int fdlastfile_single(struct filedesc *fdp); 270struct filedesc *fdinit(void); 271struct filedesc *fdshare(struct filedesc *fdp); 272struct filedesc_to_leader * 273 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 274 struct filedesc *fdp, struct proc *leader); 275struct filedesc_to_leader * 276 filedesc_to_leader_share(struct filedesc_to_leader *fdtol, 277 struct filedesc *fdp); 278int getvnode(struct thread *td, int fd, cap_rights_t *rightsp, 279 struct file **fpp); 280int getvnode_path(struct thread *td, int fd, cap_rights_t *rightsp, 281 struct file **fpp); 282void mountcheckdirs(struct vnode *olddp, struct vnode *newdp); 283 284int fget_cap_noref(struct filedesc *fdp, int fd, cap_rights_t *needrightsp, 285 struct file **fpp, struct filecaps *havecapsp); 286int fget_cap(struct thread *td, int fd, cap_rights_t *needrightsp, 287 struct file **fpp, struct filecaps *havecapsp); 288/* Return a referenced file from an unlocked descriptor. */ 289int fget_unlocked(struct thread *td, int fd, cap_rights_t *needrightsp, 290 struct file **fpp); 291/* Return a file pointer without a ref. FILEDESC_IS_ONLY_USER must be true. */ 292int fget_only_user(struct filedesc *fdp, int fd, cap_rights_t *needrightsp, 293 struct file **fpp); 294#define fput_only_user(fdp, fp) ({ \ 295 MPASS(FILEDESC_IS_ONLY_USER(fdp)); \ 296 MPASS(refcount_load(&fp->f_count) > 0); \ 297}) 298 299/* Requires a FILEDESC_{S,X}LOCK held and returns without a ref. */ 300static __inline struct file * 301fget_noref(struct filedesc *fdp, int fd) 302{ 303 304 FILEDESC_LOCK_ASSERT(fdp); 305 306 if (__predict_false((u_int)fd >= (u_int)fdp->fd_nfiles)) 307 return (NULL); 308 309 return (fdp->fd_ofiles[fd].fde_file); 310} 311 312static __inline struct filedescent * 313fdeget_noref(struct filedesc *fdp, int fd) 314{ 315 struct filedescent *fde; 316 317 FILEDESC_LOCK_ASSERT(fdp); 318 319 if (__predict_false((u_int)fd >= (u_int)fdp->fd_nfiles)) 320 return (NULL); 321 322 fde = &fdp->fd_ofiles[fd]; 323 if (__predict_false(fde->fde_file == NULL)) 324 return (NULL); 325 326 return (fde); 327} 328 329#ifdef CAPABILITIES 330static __inline bool 331fd_modified(struct filedesc *fdp, int fd, seqc_t seqc) 332{ 333 334 return (!seqc_consistent(fd_seqc(fdp->fd_files, fd), seqc)); 335} 336#endif 337 338/* cdir/rdir/jdir manipulation functions. */ 339struct pwddesc *pdcopy(struct pwddesc *pdp); 340void pdescfree(struct thread *td); 341struct pwddesc *pdinit(struct pwddesc *pdp, bool keeplock); 342struct pwddesc *pdshare(struct pwddesc *pdp); 343void pdunshare(struct thread *td); 344 345void pwd_altroot(struct thread *td, struct vnode *altroot_vp); 346void pwd_chdir(struct thread *td, struct vnode *vp); 347int pwd_chroot(struct thread *td, struct vnode *vp); 348int pwd_chroot_chdir(struct thread *td, struct vnode *vp); 349void pwd_ensure_dirs(void); 350void pwd_set_rootvnode(void); 351 352struct pwd *pwd_hold_pwddesc(struct pwddesc *pdp); 353bool pwd_hold_smr(struct pwd *pwd); 354struct pwd *pwd_hold_proc(struct proc *p); 355struct pwd *pwd_hold(struct thread *td); 356void pwd_drop(struct pwd *pwd); 357static inline void 358pwd_set(struct pwddesc *pdp, struct pwd *newpwd) 359{ 360 smr_serialized_store(&pdp->pd_pwd, newpwd, 361 (PWDDESC_ASSERT_XLOCKED(pdp), true)); 362} 363#define pwd_get_smr() vfs_smr_entered_load(&curproc->p_pd->pd_pwd) 364 365#endif /* _KERNEL */ 366 367#endif /* !_SYS_FILEDESC_H_ */ 368