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