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 * @(#)filedesc.h 8.1 (Berkeley) 6/2/93 32 * $FreeBSD$ 33 */ 34 35 #ifndef _SYS_FILEDESC_H_ 36 #define _SYS_FILEDESC_H_ 37 38 #include <sys/caprights.h> 39 #include <sys/queue.h> 40 #include <sys/event.h> 41 #include <sys/lock.h> 42 #include <sys/mutex.h> 43 #include <sys/priority.h> 44 #include <sys/seqc.h> 45 #include <sys/sx.h> 46 #include <sys/_smr.h> 47 #include <sys/smr_types.h> 48 49 #include <machine/_limits.h> 50 51 struct filecaps { 52 cap_rights_t fc_rights; /* per-descriptor capability rights */ 53 u_long *fc_ioctls; /* per-descriptor allowed ioctls */ 54 int16_t fc_nioctls; /* fc_ioctls array size */ 55 uint32_t fc_fcntls; /* per-descriptor allowed fcntls */ 56 }; 57 58 struct filedescent { 59 struct file *fde_file; /* file structure for open file */ 60 struct filecaps fde_caps; /* per-descriptor rights */ 61 uint8_t fde_flags; /* per-process open file flags */ 62 seqc_t fde_seqc; /* keep file and caps in sync */ 63 }; 64 #define fde_rights fde_caps.fc_rights 65 #define fde_fcntls fde_caps.fc_fcntls 66 #define fde_ioctls fde_caps.fc_ioctls 67 #define fde_nioctls fde_caps.fc_nioctls 68 #define fde_change_size (offsetof(struct filedescent, fde_seqc)) 69 70 struct fdescenttbl { 71 int fdt_nfiles; /* number of open files allocated */ 72 struct filedescent fdt_ofiles[0]; /* open files */ 73 }; 74 #define fd_seqc(fdt, fd) (&(fdt)->fdt_ofiles[(fd)].fde_seqc) 75 76 /* 77 * This structure is used for the management of descriptors. It may be 78 * shared by multiple processes. 79 */ 80 #define NDSLOTTYPE u_long 81 82 /* 83 * This struct is copy-on-write and allocated from an SMR zone. 84 * All fields are constant after initialization apart from the reference count. 85 * 86 * Check pwd_* routines for usage. 87 */ 88 struct pwd { 89 volatile u_int pwd_refcount; 90 struct vnode *pwd_cdir; /* current directory */ 91 struct vnode *pwd_rdir; /* root directory */ 92 struct vnode *pwd_jdir; /* jail root directory */ 93 }; 94 typedef SMR_POINTER(struct pwd *) smrpwd_t; 95 96 struct pwddesc { 97 struct mtx pd_lock; /* protects members of this struct */ 98 smrpwd_t pd_pwd; /* directories */ 99 volatile u_int pd_refcount; 100 u_short pd_cmask; /* mask for file creation */ 101 }; 102 103 struct filedesc { 104 struct fdescenttbl *fd_files; /* open files table */ 105 NDSLOTTYPE *fd_map; /* bitmap of free fds */ 106 int fd_freefile; /* approx. next free file */ 107 int fd_refcnt; /* thread reference count */ 108 int fd_holdcnt; /* hold count on structure + mutex */ 109 struct sx fd_sx; /* protects members of this struct */ 110 struct kqlist fd_kqlist; /* list of kqueues on this filedesc */ 111 int fd_holdleaderscount; /* block fdfree() for shared close() */ 112 int fd_holdleaderswakeup; /* fdfree() needs wakeup */ 113 }; 114 115 /* 116 * Structure to keep track of (process leader, struct fildedesc) tuples. 117 * Each process has a pointer to such a structure when detailed tracking 118 * is needed, e.g., when rfork(RFPROC | RFMEM) causes a file descriptor 119 * table to be shared by processes having different "p_leader" pointers 120 * and thus distinct POSIX style locks. 121 * 122 * fdl_refcount and fdl_holdcount are protected by struct filedesc mtx. 123 */ 124 struct filedesc_to_leader { 125 int fdl_refcount; /* references from struct proc */ 126 int fdl_holdcount; /* temporary hold during closef */ 127 int fdl_wakeup; /* fdfree() waits on closef() */ 128 struct proc *fdl_leader; /* owner of POSIX locks */ 129 /* Circular list: */ 130 struct filedesc_to_leader *fdl_prev; 131 struct filedesc_to_leader *fdl_next; 132 }; 133 #define fd_nfiles fd_files->fdt_nfiles 134 #define fd_ofiles fd_files->fdt_ofiles 135 136 /* 137 * Per-process open flags. 138 */ 139 #define UF_EXCLOSE 0x01 /* auto-close on exec */ 140 141 #ifdef _KERNEL 142 143 /* Lock a paths descriptor table. */ 144 #define PWDDESC_LOCK(pdp) (&(pdp)->pd_lock) 145 #define PWDDESC_LOCK_INIT(pdp) \ 146 mtx_init(PWDDESC_LOCK(pdp), "pwddesc", NULL, MTX_DEF) 147 #define PWDDESC_LOCK_DESTROY(pdp) mtx_destroy(PWDDESC_LOCK(pdp)) 148 #define PWDDESC_XLOCK(pdp) mtx_lock(PWDDESC_LOCK(pdp)) 149 #define PWDDESC_XUNLOCK(pdp) mtx_unlock(PWDDESC_LOCK(pdp)) 150 #define PWDDESC_LOCK_ASSERT(pdp, what) \ 151 mtx_assert(PWDDESC_LOCK(pdp), (what)) 152 #define PWDDESC_ASSERT_XLOCKED(pdp) \ 153 PWDDESC_LOCK_ASSERT((pdp), MA_OWNED) 154 #define PWDDESC_ASSERT_UNLOCKED(pdp) \ 155 PWDDESC_LOCK_ASSERT((pdp), MA_NOTOWNED) 156 157 #define PWDDESC_XLOCKED_LOAD_PWD(pdp) ({ \ 158 struct pwddesc *_pdp = (pdp); \ 159 struct pwd *_pwd; \ 160 _pwd = smr_serialized_load(&(_pdp)->pd_pwd, \ 161 (PWDDESC_ASSERT_XLOCKED(_pdp), true)); \ 162 _pwd; \ 163 }) 164 165 /* Lock a file descriptor table. */ 166 #define FILEDESC_LOCK_INIT(fdp) sx_init(&(fdp)->fd_sx, "filedesc structure") 167 #define FILEDESC_LOCK_DESTROY(fdp) sx_destroy(&(fdp)->fd_sx) 168 #define FILEDESC_LOCK(fdp) (&(fdp)->fd_sx) 169 #define FILEDESC_XLOCK(fdp) sx_xlock(&(fdp)->fd_sx) 170 #define FILEDESC_XUNLOCK(fdp) sx_xunlock(&(fdp)->fd_sx) 171 #define FILEDESC_SLOCK(fdp) sx_slock(&(fdp)->fd_sx) 172 #define FILEDESC_SUNLOCK(fdp) sx_sunlock(&(fdp)->fd_sx) 173 174 #define FILEDESC_LOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_LOCKED | \ 175 SX_NOTRECURSED) 176 #define FILEDESC_XLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_XLOCKED | \ 177 SX_NOTRECURSED) 178 #define FILEDESC_UNLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_UNLOCKED) 179 180 #define FILEDESC_IS_ONLY_USER(fdp) ({ \ 181 struct filedesc *_fdp = (fdp); \ 182 MPASS(curproc->p_fd == _fdp); \ 183 (curproc->p_numthreads == 1 && refcount_load(&_fdp->fd_refcnt) == 1); \ 184 }) 185 #else 186 187 /* 188 * Accessor for libkvm et al. 189 */ 190 #define PWDDESC_KVM_LOAD_PWD(pdp) ({ \ 191 struct pwddesc *_pdp = (pdp); \ 192 struct pwd *_pwd; \ 193 _pwd = smr_kvm_load(&(_pdp)->pd_pwd); \ 194 _pwd; \ 195 }) 196 197 #endif 198 199 #ifdef _KERNEL 200 201 /* Operation types for kern_dup(). */ 202 enum { 203 FDDUP_NORMAL, /* dup() behavior. */ 204 FDDUP_FCNTL, /* fcntl()-style errors. */ 205 FDDUP_FIXED, /* Force fixed allocation. */ 206 FDDUP_LASTMODE, 207 }; 208 209 /* Flags for kern_dup(). */ 210 #define FDDUP_FLAG_CLOEXEC 0x1 /* Atomically set UF_EXCLOSE. */ 211 212 /* For backward compatibility. */ 213 #define falloc(td, resultfp, resultfd, flags) \ 214 falloc_caps(td, resultfp, resultfd, flags, NULL) 215 216 struct thread; 217 218 static __inline void 219 filecaps_init(struct filecaps *fcaps) 220 { 221 222 bzero(fcaps, sizeof(*fcaps)); 223 fcaps->fc_nioctls = -1; 224 } 225 bool filecaps_copy(const struct filecaps *src, struct filecaps *dst, 226 bool locked); 227 void filecaps_move(struct filecaps *src, struct filecaps *dst); 228 void filecaps_free(struct filecaps *fcaps); 229 230 int closef(struct file *fp, struct thread *td); 231 void closef_nothread(struct file *fp); 232 int dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode, 233 int openerror, int *indxp); 234 int falloc_caps(struct thread *td, struct file **resultfp, int *resultfd, 235 int flags, struct filecaps *fcaps); 236 void falloc_abort(struct thread *td, struct file *fp); 237 int _falloc_noinstall(struct thread *td, struct file **resultfp, u_int n); 238 #define falloc_noinstall(td, resultfp) _falloc_noinstall(td, resultfp, 1) 239 void _finstall(struct filedesc *fdp, struct file *fp, int fd, int flags, 240 struct filecaps *fcaps); 241 int finstall(struct thread *td, struct file *fp, int *resultfd, int flags, 242 struct filecaps *fcaps); 243 int finstall_refed(struct thread *td, struct file *fp, int *resultfd, int flags, 244 struct filecaps *fcaps); 245 int fdalloc(struct thread *td, int minfd, int *result); 246 int fdallocn(struct thread *td, int minfd, int *fds, int n); 247 int fdcheckstd(struct thread *td); 248 void fdclose(struct thread *td, struct file *fp, int idx); 249 void fdcloseexec(struct thread *td); 250 void fdsetugidsafety(struct thread *td); 251 struct filedesc *fdcopy(struct filedesc *fdp); 252 void fdunshare(struct thread *td); 253 void fdescfree(struct thread *td); 254 int fdlastfile(struct filedesc *fdp); 255 int fdlastfile_single(struct filedesc *fdp); 256 struct filedesc *fdinit(struct filedesc *fdp, bool prepfiles, int *lastfile); 257 struct filedesc *fdshare(struct filedesc *fdp); 258 struct filedesc_to_leader * 259 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 260 struct filedesc *fdp, struct proc *leader); 261 int getvnode(struct thread *td, int fd, cap_rights_t *rightsp, 262 struct file **fpp); 263 int getvnode_path(struct thread *td, int fd, cap_rights_t *rightsp, 264 struct file **fpp); 265 void mountcheckdirs(struct vnode *olddp, struct vnode *newdp); 266 267 int fget_cap_locked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp, 268 struct file **fpp, struct filecaps *havecapsp); 269 int fget_cap(struct thread *td, int fd, cap_rights_t *needrightsp, 270 struct file **fpp, struct filecaps *havecapsp); 271 272 /* Return a referenced file from an unlocked descriptor. */ 273 int fget_unlocked_seq(struct filedesc *fdp, int fd, cap_rights_t *needrightsp, 274 struct file **fpp, seqc_t *seqp); 275 int fget_unlocked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp, 276 struct file **fpp); 277 /* Return a file pointer without a ref. FILEDESC_IS_ONLY_USER must be true. */ 278 int fget_only_user(struct filedesc *fdp, int fd, cap_rights_t *needrightsp, 279 struct file **fpp); 280 #define fput_only_user(fdp, fp) ({ \ 281 MPASS(FILEDESC_IS_ONLY_USER(fdp)); \ 282 MPASS(refcount_load(&fp->f_count) > 0); \ 283 }) 284 285 /* Requires a FILEDESC_{S,X}LOCK held and returns without a ref. */ 286 static __inline struct file * 287 fget_locked(struct filedesc *fdp, int fd) 288 { 289 290 FILEDESC_LOCK_ASSERT(fdp); 291 292 if (__predict_false((u_int)fd >= fdp->fd_nfiles)) 293 return (NULL); 294 295 return (fdp->fd_ofiles[fd].fde_file); 296 } 297 298 static __inline struct filedescent * 299 fdeget_locked(struct filedesc *fdp, int fd) 300 { 301 struct filedescent *fde; 302 303 FILEDESC_LOCK_ASSERT(fdp); 304 305 if (__predict_false((u_int)fd >= fdp->fd_nfiles)) 306 return (NULL); 307 308 fde = &fdp->fd_ofiles[fd]; 309 if (__predict_false(fde->fde_file == NULL)) 310 return (NULL); 311 312 return (fde); 313 } 314 315 #ifdef CAPABILITIES 316 static __inline bool 317 fd_modified(struct filedesc *fdp, int fd, seqc_t seqc) 318 { 319 320 return (!seqc_consistent(fd_seqc(fdp->fd_files, fd), seqc)); 321 } 322 #endif 323 324 /* cdir/rdir/jdir manipulation functions. */ 325 struct pwddesc *pdcopy(struct pwddesc *pdp); 326 void pdescfree(struct thread *td); 327 struct pwddesc *pdinit(struct pwddesc *pdp, bool keeplock); 328 struct pwddesc *pdshare(struct pwddesc *pdp); 329 void pdunshare(struct thread *td); 330 331 void pwd_chdir(struct thread *td, struct vnode *vp); 332 int pwd_chroot(struct thread *td, struct vnode *vp); 333 int pwd_chroot_chdir(struct thread *td, struct vnode *vp); 334 void pwd_ensure_dirs(void); 335 void pwd_set_rootvnode(void); 336 337 struct pwd *pwd_hold_pwddesc(struct pwddesc *pdp); 338 bool pwd_hold_smr(struct pwd *pwd); 339 struct pwd *pwd_hold_proc(struct proc *p); 340 struct pwd *pwd_hold(struct thread *td); 341 void pwd_drop(struct pwd *pwd); 342 static inline void 343 pwd_set(struct pwddesc *pdp, struct pwd *newpwd) 344 { 345 smr_serialized_store(&pdp->pd_pwd, newpwd, 346 (PWDDESC_ASSERT_XLOCKED(pdp), true)); 347 } 348 #define pwd_get_smr() vfs_smr_entered_load(&curproc->p_pd->pd_pwd) 349 350 #endif /* _KERNEL */ 351 352 #endif /* !_SYS_FILEDESC_H_ */ 353