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 49 struct 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 56 struct 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 68 static inline void 69 fde_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 78 struct 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 */ 94 struct 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 }; 101 typedef SMR_POINTER(struct pwd *) smrpwd_t; 102 103 struct 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 */ 114 struct 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 */ 135 struct 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 #define UF_RESOLVE_BENEATH 0x02 /* lookups must be beneath this dir */ 152 #define UF_FOCLOSE 0x04 /* auto-close on fork */ 153 154 #ifdef _KERNEL 155 156 /* Lock a paths descriptor table. */ 157 #define PWDDESC_LOCK(pdp) (&(pdp)->pd_lock) 158 #define PWDDESC_LOCK_INIT(pdp) \ 159 mtx_init(PWDDESC_LOCK(pdp), "pwddesc", NULL, MTX_DEF) 160 #define PWDDESC_LOCK_DESTROY(pdp) mtx_destroy(PWDDESC_LOCK(pdp)) 161 #define PWDDESC_XLOCK(pdp) mtx_lock(PWDDESC_LOCK(pdp)) 162 #define PWDDESC_XUNLOCK(pdp) mtx_unlock(PWDDESC_LOCK(pdp)) 163 #define PWDDESC_LOCK_ASSERT(pdp, what) \ 164 mtx_assert(PWDDESC_LOCK(pdp), (what)) 165 #define PWDDESC_ASSERT_XLOCKED(pdp) \ 166 PWDDESC_LOCK_ASSERT((pdp), MA_OWNED) 167 #define PWDDESC_ASSERT_UNLOCKED(pdp) \ 168 PWDDESC_LOCK_ASSERT((pdp), MA_NOTOWNED) 169 170 #define PWDDESC_XLOCKED_LOAD_PWD(pdp) ({ \ 171 struct pwddesc *_pdp = (pdp); \ 172 struct pwd *_pwd; \ 173 _pwd = smr_serialized_load(&(_pdp)->pd_pwd, \ 174 (PWDDESC_ASSERT_XLOCKED(_pdp), true)); \ 175 _pwd; \ 176 }) 177 178 /* Lock a file descriptor table. */ 179 #define FILEDESC_LOCK_INIT(fdp) sx_init(&(fdp)->fd_sx, "filedesc structure") 180 #define FILEDESC_LOCK_DESTROY(fdp) sx_destroy(&(fdp)->fd_sx) 181 #define FILEDESC_LOCK(fdp) (&(fdp)->fd_sx) 182 #define FILEDESC_XLOCK(fdp) sx_xlock(&(fdp)->fd_sx) 183 #define FILEDESC_XUNLOCK(fdp) sx_xunlock(&(fdp)->fd_sx) 184 #define FILEDESC_SLOCK(fdp) sx_slock(&(fdp)->fd_sx) 185 #define FILEDESC_SUNLOCK(fdp) sx_sunlock(&(fdp)->fd_sx) 186 187 #define FILEDESC_LOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_LOCKED | \ 188 SX_NOTRECURSED) 189 #define FILEDESC_XLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_XLOCKED | \ 190 SX_NOTRECURSED) 191 #define FILEDESC_UNLOCK_ASSERT(fdp) sx_assert(&(fdp)->fd_sx, SX_UNLOCKED) 192 193 #define FILEDESC_IS_ONLY_USER(fdp) ({ \ 194 struct filedesc *_fdp = (fdp); \ 195 MPASS(curproc->p_fd == _fdp); \ 196 (curproc->p_numthreads == 1 && refcount_load(&_fdp->fd_refcnt) == 1); \ 197 }) 198 199 #else 200 201 /* 202 * Accessor for libkvm et al. 203 */ 204 #define PWDDESC_KVM_LOAD_PWD(pdp) ({ \ 205 struct pwddesc *_pdp = (pdp); \ 206 struct pwd *_pwd; \ 207 _pwd = smr_kvm_load(&(_pdp)->pd_pwd); \ 208 _pwd; \ 209 }) 210 211 #endif 212 213 #ifdef _KERNEL 214 215 #include <machine/atomic.h> 216 217 /* Operation types for kern_dup(). */ 218 enum { 219 FDDUP_NORMAL, /* dup() behavior. */ 220 FDDUP_FCNTL, /* fcntl()-style errors. */ 221 FDDUP_FIXED, /* Force fixed allocation. */ 222 FDDUP_LASTMODE, 223 }; 224 225 /* Flags for kern_dup(). */ 226 #define FDDUP_FLAG_CLOEXEC 0x1 /* Atomically set UF_EXCLOSE. */ 227 #define FDDUP_FLAG_CLOFORK 0x2 /* Atomically set UF_FOCLOSE. */ 228 229 /* For backward compatibility. */ 230 #define falloc(td, resultfp, resultfd, flags) \ 231 falloc_caps(td, resultfp, resultfd, flags, NULL) 232 233 struct mount; 234 struct thread; 235 236 static __inline void 237 filecaps_init(struct filecaps *fcaps) 238 { 239 240 bzero(fcaps, sizeof(*fcaps)); 241 fcaps->fc_nioctls = -1; 242 } 243 bool filecaps_copy(const struct filecaps *src, struct filecaps *dst, 244 bool locked); 245 void filecaps_move(struct filecaps *src, struct filecaps *dst); 246 void filecaps_fill(struct filecaps *fcaps); 247 void filecaps_free(struct filecaps *fcaps); 248 bool filecaps_full(const struct filecaps *fcaps); 249 void filecaps_intersect(struct filecaps *src, struct filecaps *dst); 250 251 int closef(struct file *fp, struct thread *td); 252 void closef_nothread(struct file *fp); 253 int descrip_check_write_mp(struct filedesc *fdp, struct mount *mp); 254 int dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode, 255 int openerror, int *indxp); 256 int falloc_caps(struct thread *td, struct file **resultfp, int *resultfd, 257 int flags, struct filecaps *fcaps); 258 void falloc_abort(struct thread *td, struct file *fp); 259 int _falloc_noinstall(struct thread *td, struct file **resultfp, u_int n); 260 #define falloc_noinstall(td, resultfp) _falloc_noinstall(td, resultfp, 1) 261 void _finstall(struct filedesc *fdp, struct file *fp, int fd, int flags, 262 struct filecaps *fcaps); 263 int finstall(struct thread *td, struct file *fp, int *resultfd, int flags, 264 struct filecaps *fcaps); 265 int finstall_refed(struct thread *td, struct file *fp, int *resultfd, int flags, 266 struct filecaps *fcaps); 267 int fdalloc(struct thread *td, int minfd, int *result); 268 int fdallocn(struct thread *td, int minfd, int *fds, int n); 269 int fdcheckstd(struct thread *td); 270 void fdclose(struct thread *td, struct file *fp, int idx); 271 void fdcloseexec(struct thread *td); 272 void fdsetugidsafety(struct thread *td); 273 struct filedesc *fdcopy(struct filedesc *fdp, struct proc *p1); 274 void fdunshare(struct thread *td); 275 void fdescfree(struct thread *td); 276 int fdlastfile(struct filedesc *fdp); 277 int fdlastfile_single(struct filedesc *fdp); 278 struct filedesc *fdinit(void); 279 struct filedesc *fdshare(struct filedesc *fdp); 280 struct filedesc_to_leader * 281 filedesc_to_leader_alloc(struct filedesc_to_leader *old, 282 struct filedesc *fdp, struct proc *leader); 283 struct filedesc_to_leader * 284 filedesc_to_leader_share(struct filedesc_to_leader *fdtol, 285 struct filedesc *fdp); 286 int getvnode(struct thread *td, int fd, const cap_rights_t *rightsp, 287 struct file **fpp); 288 int getvnode_path(struct thread *td, int fd, const cap_rights_t *rightsp, 289 uint8_t *flagsp, struct file **fpp); 290 void mountcheckdirs(struct vnode *olddp, struct vnode *newdp); 291 292 int fget_cap_noref(struct filedesc *fdp, int fd, 293 const cap_rights_t *needrightsp, struct file **fpp, 294 struct filecaps *havecapsp); 295 int fget_cap(struct thread *td, int fd, const cap_rights_t *needrightsp, 296 uint8_t *flagsp, struct file **fpp, struct filecaps *havecapsp); 297 /* Return a referenced file from an unlocked descriptor. */ 298 int fget_unlocked(struct thread *td, int fd, 299 const cap_rights_t *needrightsp, struct file **fpp); 300 int fget_unlocked_flags(struct thread *td, int fd, 301 const cap_rights_t *needrightsp, uint8_t *flagsp, 302 struct file **fpp); 303 /* Return a file pointer without a ref. FILEDESC_IS_ONLY_USER must be true. */ 304 int fget_only_user(struct filedesc *fdp, int fd, 305 const cap_rights_t *needrightsp, struct file **fpp); 306 #define fput_only_user(fdp, fp) ({ \ 307 MPASS(FILEDESC_IS_ONLY_USER(fdp)); \ 308 MPASS(refcount_load(&fp->f_count) > 0); \ 309 }) 310 311 /* 312 * Look up a file description without requiring a lock. In general the result 313 * may be immediately invalidated after the function returns, the caller must 314 * handle this. 315 */ 316 static inline struct file * 317 fget_noref_unlocked(struct filedesc *fdp, int fd) 318 { 319 if (__predict_false( 320 (u_int)fd >= (u_int)atomic_load_int(&fdp->fd_nfiles))) 321 return (NULL); 322 323 return (atomic_load_ptr(&fdp->fd_ofiles[fd].fde_file)); 324 } 325 326 /* Requires a FILEDESC_{S,X}LOCK held and returns without a ref. */ 327 static __inline struct file * 328 fget_noref(struct filedesc *fdp, int fd) 329 { 330 331 FILEDESC_LOCK_ASSERT(fdp); 332 333 if (__predict_false((u_int)fd >= (u_int)fdp->fd_nfiles)) 334 return (NULL); 335 336 return (fdp->fd_ofiles[fd].fde_file); 337 } 338 339 static __inline struct filedescent * 340 fdeget_noref(struct filedesc *fdp, int fd) 341 { 342 struct filedescent *fde; 343 344 FILEDESC_LOCK_ASSERT(fdp); 345 346 if (__predict_false((u_int)fd >= (u_int)fdp->fd_nfiles)) 347 return (NULL); 348 349 fde = &fdp->fd_ofiles[fd]; 350 if (__predict_false(fde->fde_file == NULL)) 351 return (NULL); 352 353 return (fde); 354 } 355 356 #ifdef CAPABILITIES 357 static __inline bool 358 fd_modified(struct filedesc *fdp, int fd, seqc_t seqc) 359 { 360 361 return (!seqc_consistent(fd_seqc(fdp->fd_files, fd), seqc)); 362 } 363 #endif 364 365 int proc_nfiles(struct proc *p); 366 367 /* cdir/rdir/jdir manipulation functions. */ 368 struct pwddesc *pdcopy(struct pwddesc *pdp); 369 void pdescfree(struct thread *td); 370 struct pwddesc *pdinit(struct pwddesc *pdp, bool keeplock); 371 struct pwddesc *pdshare(struct pwddesc *pdp); 372 void pdunshare(struct thread *td); 373 374 void pwd_altroot(struct thread *td, struct vnode *altroot_vp); 375 void pwd_chdir(struct thread *td, struct vnode *vp); 376 int pwd_chroot(struct thread *td, struct vnode *vp); 377 int pwd_chroot_chdir(struct thread *td, struct vnode *vp); 378 void pwd_ensure_dirs(void); 379 void pwd_set_rootvnode(void); 380 381 struct pwd *pwd_hold_pwddesc(struct pwddesc *pdp); 382 bool pwd_hold_smr(struct pwd *pwd); 383 struct pwd *pwd_hold_proc(struct proc *p); 384 struct pwd *pwd_hold(struct thread *td); 385 void pwd_drop(struct pwd *pwd); 386 static inline void 387 pwd_set(struct pwddesc *pdp, struct pwd *newpwd) 388 { 389 smr_serialized_store(&pdp->pd_pwd, newpwd, 390 (PWDDESC_ASSERT_XLOCKED(pdp), true)); 391 } 392 #define pwd_get_smr() vfs_smr_entered_load(&curproc->p_pd->pd_pwd) 393 394 #endif /* _KERNEL */ 395 396 #endif /* !_SYS_FILEDESC_H_ */ 397