/* $OpenBSD: kern_descrip.c,v 1.205 2022/01/20 11:06:57 bluhm Exp $ */ /* $NetBSD: kern_descrip.c,v 1.42 1996/03/30 22:24:38 christos Exp $ */ /* * Copyright (c) 1982, 1986, 1989, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * 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. * * @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Descriptor management. * * We need to block interrupts as long as `fhdlk' is being taken * with and without the KERNEL_LOCK(). */ struct mutex fhdlk = MUTEX_INITIALIZER(IPL_MPFLOOR); struct filelist filehead; /* head of list of open files */ int numfiles; /* actual number of open files */ static __inline void fd_used(struct filedesc *, int); static __inline void fd_unused(struct filedesc *, int); static __inline int find_next_zero(u_int *, int, u_int); static __inline int fd_inuse(struct filedesc *, int); int finishdup(struct proc *, struct file *, int, int, register_t *, int); int find_last_set(struct filedesc *, int); int dodup3(struct proc *, int, int, int, register_t *); #define DUPF_CLOEXEC 0x01 #define DUPF_DUP2 0x02 struct pool file_pool; struct pool fdesc_pool; void filedesc_init(void) { pool_init(&file_pool, sizeof(struct file), 0, IPL_MPFLOOR, PR_WAITOK, "filepl", NULL); pool_init(&fdesc_pool, sizeof(struct filedesc0), 0, IPL_NONE, PR_WAITOK, "fdescpl", NULL); LIST_INIT(&filehead); } static __inline int find_next_zero (u_int *bitmap, int want, u_int bits) { int i, off, maxoff; u_int sub; if (want > bits) return -1; off = want >> NDENTRYSHIFT; i = want & NDENTRYMASK; if (i) { sub = bitmap[off] | ((u_int)~0 >> (NDENTRIES - i)); if (sub != ~0) goto found; off++; } maxoff = NDLOSLOTS(bits); while (off < maxoff) { if ((sub = bitmap[off]) != ~0) goto found; off++; } return -1; found: return (off << NDENTRYSHIFT) + ffs(~sub) - 1; } int find_last_set(struct filedesc *fd, int last) { int off, i; u_int *bitmap = fd->fd_lomap; off = (last - 1) >> NDENTRYSHIFT; while (off >= 0 && !bitmap[off]) off--; if (off < 0) return 0; i = ((off + 1) << NDENTRYSHIFT) - 1; if (i >= last) i = last - 1; while (i > 0 && !fd_inuse(fd, i)) i--; return i; } static __inline int fd_inuse(struct filedesc *fdp, int fd) { u_int off = fd >> NDENTRYSHIFT; if (fdp->fd_lomap[off] & (1U << (fd & NDENTRYMASK))) return 1; return 0; } static __inline void fd_used(struct filedesc *fdp, int fd) { u_int off = fd >> NDENTRYSHIFT; fdp->fd_lomap[off] |= 1U << (fd & NDENTRYMASK); if (fdp->fd_lomap[off] == ~0) fdp->fd_himap[off >> NDENTRYSHIFT] |= 1U << (off & NDENTRYMASK); if (fd > fdp->fd_lastfile) fdp->fd_lastfile = fd; fdp->fd_openfd++; } static __inline void fd_unused(struct filedesc *fdp, int fd) { u_int off = fd >> NDENTRYSHIFT; if (fd < fdp->fd_freefile) fdp->fd_freefile = fd; if (fdp->fd_lomap[off] == ~0) fdp->fd_himap[off >> NDENTRYSHIFT] &= ~(1U << (off & NDENTRYMASK)); fdp->fd_lomap[off] &= ~(1U << (fd & NDENTRYMASK)); #ifdef DIAGNOSTIC if (fd > fdp->fd_lastfile) panic("fd_unused: fd_lastfile inconsistent"); #endif if (fd == fdp->fd_lastfile) fdp->fd_lastfile = find_last_set(fdp, fd); fdp->fd_openfd--; } struct file * fd_iterfile(struct file *fp, struct proc *p) { struct file *nfp; unsigned int count; mtx_enter(&fhdlk); if (fp == NULL) nfp = LIST_FIRST(&filehead); else nfp = LIST_NEXT(fp, f_list); /* don't refcount when f_count == 0 to avoid race in fdrop() */ while (nfp != NULL) { count = nfp->f_count; if (count == 0) { nfp = LIST_NEXT(nfp, f_list); continue; } if (atomic_cas_uint(&nfp->f_count, count, count + 1) == count) break; } mtx_leave(&fhdlk); if (fp != NULL) FRELE(fp, p); return nfp; } struct file * fd_getfile(struct filedesc *fdp, int fd) { struct file *fp; vfs_stall_barrier(); if ((u_int)fd >= fdp->fd_nfiles) return (NULL); mtx_enter(&fdp->fd_fplock); fp = fdp->fd_ofiles[fd]; if (fp != NULL) atomic_inc_int(&fp->f_count); mtx_leave(&fdp->fd_fplock); return (fp); } struct file * fd_getfile_mode(struct filedesc *fdp, int fd, int mode) { struct file *fp; KASSERT(mode != 0); fp = fd_getfile(fdp, fd); if (fp == NULL) return (NULL); if ((fp->f_flag & mode) == 0) { FRELE(fp, curproc); return (NULL); } return (fp); } int fd_checkclosed(struct filedesc *fdp, int fd, struct file *fp) { int closed; mtx_enter(&fdp->fd_fplock); KASSERT(fd < fdp->fd_nfiles); closed = (fdp->fd_ofiles[fd] != fp); mtx_leave(&fdp->fd_fplock); return (closed); } /* * System calls on descriptors. */ /* * Duplicate a file descriptor. */ int sys_dup(struct proc *p, void *v, register_t *retval) { struct sys_dup_args /* { syscallarg(int) fd; } */ *uap = v; struct filedesc *fdp = p->p_fd; int old = SCARG(uap, fd); struct file *fp; int new; int error; restart: if ((fp = fd_getfile(fdp, old)) == NULL) return (EBADF); fdplock(fdp); if ((error = fdalloc(p, 0, &new)) != 0) { if (error == ENOSPC) { fdexpand(p); fdpunlock(fdp); FRELE(fp, p); goto restart; } fdpunlock(fdp); FRELE(fp, p); return (error); } /* No need for FRELE(), finishdup() uses current ref. */ return (finishdup(p, fp, old, new, retval, 0)); } /* * Duplicate a file descriptor to a particular value. */ int sys_dup2(struct proc *p, void *v, register_t *retval) { struct sys_dup2_args /* { syscallarg(int) from; syscallarg(int) to; } */ *uap = v; return (dodup3(p, SCARG(uap, from), SCARG(uap, to), 0, retval)); } int sys_dup3(struct proc *p, void *v, register_t *retval) { struct sys_dup3_args /* { syscallarg(int) from; syscallarg(int) to; syscallarg(int) flags; } */ *uap = v; if (SCARG(uap, from) == SCARG(uap, to)) return (EINVAL); if (SCARG(uap, flags) & ~O_CLOEXEC) return (EINVAL); return (dodup3(p, SCARG(uap, from), SCARG(uap, to), SCARG(uap, flags), retval)); } int dodup3(struct proc *p, int old, int new, int flags, register_t *retval) { struct filedesc *fdp = p->p_fd; struct file *fp; int dupflags, error, i; restart: if ((fp = fd_getfile(fdp, old)) == NULL) return (EBADF); if (old == new) { /* * NOTE! This doesn't clear the close-on-exec flag. This might * or might not be the intended behavior from the start, but * this is what everyone else does. */ *retval = new; FRELE(fp, p); return (0); } if ((u_int)new >= lim_cur(RLIMIT_NOFILE) || (u_int)new >= maxfiles) { FRELE(fp, p); return (EBADF); } fdplock(fdp); if (new >= fdp->fd_nfiles) { if ((error = fdalloc(p, new, &i)) != 0) { if (error == ENOSPC) { fdexpand(p); fdpunlock(fdp); FRELE(fp, p); goto restart; } fdpunlock(fdp); FRELE(fp, p); return (error); } if (new != i) panic("dup2: fdalloc"); fd_unused(fdp, new); } dupflags = DUPF_DUP2; if (flags & O_CLOEXEC) dupflags |= DUPF_CLOEXEC; /* No need for FRELE(), finishdup() uses current ref. */ return (finishdup(p, fp, old, new, retval, dupflags)); } /* * The file control system call. */ int sys_fcntl(struct proc *p, void *v, register_t *retval) { struct sys_fcntl_args /* { syscallarg(int) fd; syscallarg(int) cmd; syscallarg(void *) arg; } */ *uap = v; int fd = SCARG(uap, fd); struct filedesc *fdp = p->p_fd; struct file *fp; struct vnode *vp; int i, prev, tmp, newmin, flg = F_POSIX; struct flock fl; int error = 0; error = pledge_fcntl(p, SCARG(uap, cmd)); if (error) return (error); restart: if ((fp = fd_getfile(fdp, fd)) == NULL) return (EBADF); switch (SCARG(uap, cmd)) { case F_DUPFD: case F_DUPFD_CLOEXEC: newmin = (long)SCARG(uap, arg); if ((u_int)newmin >= lim_cur(RLIMIT_NOFILE) || (u_int)newmin >= maxfiles) { error = EINVAL; break; } fdplock(fdp); if ((error = fdalloc(p, newmin, &i)) != 0) { if (error == ENOSPC) { fdexpand(p); fdpunlock(fdp); FRELE(fp, p); goto restart; } fdpunlock(fdp); FRELE(fp, p); } else { int dupflags = 0; if (SCARG(uap, cmd) == F_DUPFD_CLOEXEC) dupflags |= DUPF_CLOEXEC; /* No need for FRELE(), finishdup() uses current ref. */ error = finishdup(p, fp, fd, i, retval, dupflags); } return (error); case F_GETFD: fdplock(fdp); *retval = fdp->fd_ofileflags[fd] & UF_EXCLOSE ? 1 : 0; fdpunlock(fdp); break; case F_SETFD: fdplock(fdp); if ((long)SCARG(uap, arg) & 1) fdp->fd_ofileflags[fd] |= UF_EXCLOSE; else fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE; fdpunlock(fdp); break; case F_GETFL: *retval = OFLAGS(fp->f_flag); break; case F_ISATTY: vp = fp->f_data; if (fp->f_type == DTYPE_VNODE && (vp->v_flag & VISTTY)) *retval = 1; else { *retval = 0; error = ENOTTY; } break; case F_SETFL: do { tmp = prev = fp->f_flag; tmp &= ~FCNTLFLAGS; tmp |= FFLAGS((long)SCARG(uap, arg)) & FCNTLFLAGS; } while (atomic_cas_uint(&fp->f_flag, prev, tmp) != prev); tmp = fp->f_flag & FNONBLOCK; error = (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p); if (error) break; tmp = fp->f_flag & FASYNC; error = (*fp->f_ops->fo_ioctl)(fp, FIOASYNC, (caddr_t)&tmp, p); if (!error) break; atomic_clearbits_int(&fp->f_flag, FNONBLOCK); tmp = 0; (void) (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p); break; case F_GETOWN: tmp = 0; error = (*fp->f_ops->fo_ioctl) (fp, FIOGETOWN, (caddr_t)&tmp, p); *retval = tmp; break; case F_SETOWN: tmp = (long)SCARG(uap, arg); error = ((*fp->f_ops->fo_ioctl) (fp, FIOSETOWN, (caddr_t)&tmp, p)); break; case F_SETLKW: flg |= F_WAIT; /* FALLTHROUGH */ case F_SETLK: error = pledge_flock(p); if (error != 0) break; if (fp->f_type != DTYPE_VNODE) { error = EINVAL; break; } vp = fp->f_data; /* Copy in the lock structure */ error = copyin((caddr_t)SCARG(uap, arg), (caddr_t)&fl, sizeof (fl)); if (error) break; #ifdef KTRACE if (KTRPOINT(p, KTR_STRUCT)) ktrflock(p, &fl); #endif if (fl.l_whence == SEEK_CUR) { off_t offset = foffset(fp); if (fl.l_start == 0 && fl.l_len < 0) { /* lockf(3) compliance hack */ fl.l_len = -fl.l_len; fl.l_start = offset - fl.l_len; } else fl.l_start += offset; } switch (fl.l_type) { case F_RDLCK: if ((fp->f_flag & FREAD) == 0) { error = EBADF; goto out; } atomic_setbits_int(&fdp->fd_flags, FD_ADVLOCK); error = VOP_ADVLOCK(vp, fdp, F_SETLK, &fl, flg); break; case F_WRLCK: if ((fp->f_flag & FWRITE) == 0) { error = EBADF; goto out; } atomic_setbits_int(&fdp->fd_flags, FD_ADVLOCK); error = VOP_ADVLOCK(vp, fdp, F_SETLK, &fl, flg); break; case F_UNLCK: error = VOP_ADVLOCK(vp, fdp, F_UNLCK, &fl, F_POSIX); goto out; default: error = EINVAL; goto out; } if (fd_checkclosed(fdp, fd, fp)) { /* * We have lost the race with close() or dup2(); * unlock, pretend that we've won the race and that * lock had been removed by close() */ fl.l_whence = SEEK_SET; fl.l_start = 0; fl.l_len = 0; VOP_ADVLOCK(vp, fdp, F_UNLCK, &fl, F_POSIX); fl.l_type = F_UNLCK; } goto out; case F_GETLK: error = pledge_flock(p); if (error != 0) break; if (fp->f_type != DTYPE_VNODE) { error = EINVAL; break; } vp = fp->f_data; /* Copy in the lock structure */ error = copyin((caddr_t)SCARG(uap, arg), (caddr_t)&fl, sizeof (fl)); if (error) break; if (fl.l_whence == SEEK_CUR) { off_t offset = foffset(fp); if (fl.l_start == 0 && fl.l_len < 0) { /* lockf(3) compliance hack */ fl.l_len = -fl.l_len; fl.l_start = offset - fl.l_len; } else fl.l_start += offset; } if (fl.l_type != F_RDLCK && fl.l_type != F_WRLCK && fl.l_type != F_UNLCK && fl.l_type != 0) { error = EINVAL; break; } error = VOP_ADVLOCK(vp, fdp, F_GETLK, &fl, F_POSIX); if (error) break; #ifdef KTRACE if (KTRPOINT(p, KTR_STRUCT)) ktrflock(p, &fl); #endif error = (copyout((caddr_t)&fl, (caddr_t)SCARG(uap, arg), sizeof (fl))); break; default: error = EINVAL; break; } out: FRELE(fp, p); return (error); } /* * Common code for dup, dup2, and fcntl(F_DUPFD). */ int finishdup(struct proc *p, struct file *fp, int old, int new, register_t *retval, int dupflags) { struct file *oldfp; struct filedesc *fdp = p->p_fd; int error; fdpassertlocked(fdp); KASSERT(fp->f_iflags & FIF_INSERTED); if (fp->f_count >= FDUP_MAX_COUNT) { error = EDEADLK; goto fail; } oldfp = fd_getfile(fdp, new); if ((dupflags & DUPF_DUP2) && oldfp == NULL) { if (fd_inuse(fdp, new)) { error = EBUSY; goto fail; } fd_used(fdp, new); } /* * Use `fd_fplock' to synchronize with fd_getfile() so that * the function no longer creates a new reference to the old file. */ mtx_enter(&fdp->fd_fplock); fdp->fd_ofiles[new] = fp; mtx_leave(&fdp->fd_fplock); fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] & ~UF_EXCLOSE; if (dupflags & DUPF_CLOEXEC) fdp->fd_ofileflags[new] |= UF_EXCLOSE; *retval = new; if (oldfp != NULL) { knote_fdclose(p, new); fdpunlock(fdp); closef(oldfp, p); } else { fdpunlock(fdp); } return (0); fail: fdpunlock(fdp); FRELE(fp, p); return (error); } void fdinsert(struct filedesc *fdp, int fd, int flags, struct file *fp) { struct file *fq; fdpassertlocked(fdp); mtx_enter(&fhdlk); if ((fp->f_iflags & FIF_INSERTED) == 0) { atomic_setbits_int(&fp->f_iflags, FIF_INSERTED); if ((fq = fdp->fd_ofiles[0]) != NULL) { LIST_INSERT_AFTER(fq, fp, f_list); } else { LIST_INSERT_HEAD(&filehead, fp, f_list); } } mtx_leave(&fhdlk); mtx_enter(&fdp->fd_fplock); KASSERT(fdp->fd_ofiles[fd] == NULL); fdp->fd_ofiles[fd] = fp; mtx_leave(&fdp->fd_fplock); fdp->fd_ofileflags[fd] |= (flags & UF_EXCLOSE); } void fdremove(struct filedesc *fdp, int fd) { fdpassertlocked(fdp); /* * Use `fd_fplock' to synchronize with fd_getfile() so that * the function no longer creates a new reference to the file. */ mtx_enter(&fdp->fd_fplock); fdp->fd_ofiles[fd] = NULL; mtx_leave(&fdp->fd_fplock); fdp->fd_ofileflags[fd] = 0; fd_unused(fdp, fd); } int fdrelease(struct proc *p, int fd) { struct filedesc *fdp = p->p_fd; struct file *fp; fdpassertlocked(fdp); fp = fd_getfile(fdp, fd); if (fp == NULL) { fdpunlock(fdp); return (EBADF); } fdremove(fdp, fd); knote_fdclose(p, fd); fdpunlock(fdp); return (closef(fp, p)); } /* * Close a file descriptor. */ int sys_close(struct proc *p, void *v, register_t *retval) { struct sys_close_args /* { syscallarg(int) fd; } */ *uap = v; int fd = SCARG(uap, fd), error; struct filedesc *fdp = p->p_fd; fdplock(fdp); /* fdrelease unlocks fdp. */ error = fdrelease(p, fd); return (error); } /* * Return status information about a file descriptor. */ int sys_fstat(struct proc *p, void *v, register_t *retval) { struct sys_fstat_args /* { syscallarg(int) fd; syscallarg(struct stat *) sb; } */ *uap = v; int fd = SCARG(uap, fd); struct filedesc *fdp = p->p_fd; struct file *fp; struct stat ub; int error; if ((fp = fd_getfile(fdp, fd)) == NULL) return (EBADF); error = (*fp->f_ops->fo_stat)(fp, &ub, p); FRELE(fp, p); if (error == 0) { /* * Don't let non-root see generation numbers * (for NFS security) */ if (suser(p)) ub.st_gen = 0; error = copyout((caddr_t)&ub, (caddr_t)SCARG(uap, sb), sizeof (ub)); } #ifdef KTRACE if (error == 0 && KTRPOINT(p, KTR_STRUCT)) ktrstat(p, &ub); #endif return (error); } /* * Return pathconf information about a file descriptor. */ int sys_fpathconf(struct proc *p, void *v, register_t *retval) { struct sys_fpathconf_args /* { syscallarg(int) fd; syscallarg(int) name; } */ *uap = v; int fd = SCARG(uap, fd); struct filedesc *fdp = p->p_fd; struct file *fp; struct vnode *vp; int error; if ((fp = fd_getfile(fdp, fd)) == NULL) return (EBADF); switch (fp->f_type) { case DTYPE_PIPE: case DTYPE_SOCKET: if (SCARG(uap, name) != _PC_PIPE_BUF) { error = EINVAL; break; } *retval = PIPE_BUF; error = 0; break; case DTYPE_VNODE: vp = fp->f_data; vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); error = VOP_PATHCONF(vp, SCARG(uap, name), retval); VOP_UNLOCK(vp); break; default: error = EOPNOTSUPP; break; } FRELE(fp, p); return (error); } /* * Allocate a file descriptor for the process. */ int fdalloc(struct proc *p, int want, int *result) { struct filedesc *fdp = p->p_fd; int lim, last, i; u_int new, off; fdpassertlocked(fdp); /* * Search for a free descriptor starting at the higher * of want or fd_freefile. If that fails, consider * expanding the ofile array. */ restart: lim = min((int)lim_cur(RLIMIT_NOFILE), maxfiles); last = min(fdp->fd_nfiles, lim); if ((i = want) < fdp->fd_freefile) i = fdp->fd_freefile; off = i >> NDENTRYSHIFT; new = find_next_zero(fdp->fd_himap, off, (last + NDENTRIES - 1) >> NDENTRYSHIFT); if (new != -1) { i = find_next_zero(&fdp->fd_lomap[new], new > off ? 0 : i & NDENTRYMASK, NDENTRIES); if (i == -1) { /* * Free file descriptor in this block was * below want, try again with higher want. */ want = (new + 1) << NDENTRYSHIFT; goto restart; } i += (new << NDENTRYSHIFT); if (i < last) { fd_used(fdp, i); if (want <= fdp->fd_freefile) fdp->fd_freefile = i; *result = i; fdp->fd_ofileflags[i] = 0; if (ISSET(p->p_p->ps_flags, PS_PLEDGE)) fdp->fd_ofileflags[i] |= UF_PLEDGED; return (0); } } if (fdp->fd_nfiles >= lim) return (EMFILE); return (ENOSPC); } void fdexpand(struct proc *p) { struct filedesc *fdp = p->p_fd; int nfiles, oldnfiles; size_t copylen; struct file **newofile, **oldofile; char *newofileflags; u_int *newhimap, *newlomap; fdpassertlocked(fdp); oldnfiles = fdp->fd_nfiles; oldofile = fdp->fd_ofiles; /* * No space in current array. */ if (fdp->fd_nfiles < NDEXTENT) nfiles = NDEXTENT; else nfiles = 2 * fdp->fd_nfiles; newofile = mallocarray(nfiles, OFILESIZE, M_FILEDESC, M_WAITOK); /* * Allocate all required chunks before calling free(9) to make * sure that ``fd_ofiles'' stays valid if we go to sleep. */ if (NDHISLOTS(nfiles) > NDHISLOTS(fdp->fd_nfiles)) { newhimap = mallocarray(NDHISLOTS(nfiles), sizeof(u_int), M_FILEDESC, M_WAITOK); newlomap = mallocarray(NDLOSLOTS(nfiles), sizeof(u_int), M_FILEDESC, M_WAITOK); } newofileflags = (char *) &newofile[nfiles]; /* * Copy the existing ofile and ofileflags arrays * and zero the new portion of each array. */ copylen = sizeof(struct file *) * fdp->fd_nfiles; memcpy(newofile, fdp->fd_ofiles, copylen); memset((char *)newofile + copylen, 0, nfiles * sizeof(struct file *) - copylen); copylen = sizeof(char) * fdp->fd_nfiles; memcpy(newofileflags, fdp->fd_ofileflags, copylen); memset(newofileflags + copylen, 0, nfiles * sizeof(char) - copylen); if (NDHISLOTS(nfiles) > NDHISLOTS(fdp->fd_nfiles)) { copylen = NDHISLOTS(fdp->fd_nfiles) * sizeof(u_int); memcpy(newhimap, fdp->fd_himap, copylen); memset((char *)newhimap + copylen, 0, NDHISLOTS(nfiles) * sizeof(u_int) - copylen); copylen = NDLOSLOTS(fdp->fd_nfiles) * sizeof(u_int); memcpy(newlomap, fdp->fd_lomap, copylen); memset((char *)newlomap + copylen, 0, NDLOSLOTS(nfiles) * sizeof(u_int) - copylen); if (NDHISLOTS(fdp->fd_nfiles) > NDHISLOTS(NDFILE)) { free(fdp->fd_himap, M_FILEDESC, NDHISLOTS(fdp->fd_nfiles) * sizeof(u_int)); free(fdp->fd_lomap, M_FILEDESC, NDLOSLOTS(fdp->fd_nfiles) * sizeof(u_int)); } fdp->fd_himap = newhimap; fdp->fd_lomap = newlomap; } mtx_enter(&fdp->fd_fplock); fdp->fd_ofiles = newofile; mtx_leave(&fdp->fd_fplock); fdp->fd_ofileflags = newofileflags; fdp->fd_nfiles = nfiles; if (oldnfiles > NDFILE) free(oldofile, M_FILEDESC, oldnfiles * OFILESIZE); } /* * Create a new open file structure and allocate * a file descriptor for the process that refers to it. */ int falloc(struct proc *p, struct file **resultfp, int *resultfd) { struct file *fp; int error, i; KASSERT(resultfp != NULL); KASSERT(resultfd != NULL); fdpassertlocked(p->p_fd); restart: if ((error = fdalloc(p, 0, &i)) != 0) { if (error == ENOSPC) { fdexpand(p); goto restart; } return (error); } fp = fnew(p); if (fp == NULL) { fd_unused(p->p_fd, i); return (ENFILE); } FREF(fp); *resultfp = fp; *resultfd = i; return (0); } struct file * fnew(struct proc *p) { struct file *fp; int nfiles; nfiles = atomic_inc_int_nv(&numfiles); if (nfiles > maxfiles) { atomic_dec_int(&numfiles); tablefull("file"); return (NULL); } fp = pool_get(&file_pool, PR_WAITOK|PR_ZERO); /* * We need to block interrupts as long as `f_mtx' is being taken * with and without the KERNEL_LOCK(). */ mtx_init(&fp->f_mtx, IPL_MPFLOOR); fp->f_count = 1; fp->f_cred = p->p_ucred; crhold(fp->f_cred); return (fp); } /* * Build a new filedesc structure. */ struct filedesc * fdinit(void) { struct filedesc0 *newfdp; newfdp = pool_get(&fdesc_pool, PR_WAITOK|PR_ZERO); rw_init(&newfdp->fd_fd.fd_lock, "fdlock"); mtx_init(&newfdp->fd_fd.fd_fplock, IPL_MPFLOOR); LIST_INIT(&newfdp->fd_fd.fd_kqlist); /* Create the file descriptor table. */ newfdp->fd_fd.fd_refcnt = 1; newfdp->fd_fd.fd_cmask = S_IWGRP|S_IWOTH; newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles; newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags; newfdp->fd_fd.fd_nfiles = NDFILE; newfdp->fd_fd.fd_himap = newfdp->fd_dhimap; newfdp->fd_fd.fd_lomap = newfdp->fd_dlomap; newfdp->fd_fd.fd_freefile = 0; newfdp->fd_fd.fd_lastfile = 0; return (&newfdp->fd_fd); } /* * Share a filedesc structure. */ struct filedesc * fdshare(struct process *pr) { pr->ps_fd->fd_refcnt++; return (pr->ps_fd); } /* * Copy a filedesc structure. */ struct filedesc * fdcopy(struct process *pr) { struct filedesc *newfdp, *fdp = pr->ps_fd; int i; newfdp = fdinit(); fdplock(fdp); if (fdp->fd_cdir) { vref(fdp->fd_cdir); newfdp->fd_cdir = fdp->fd_cdir; } if (fdp->fd_rdir) { vref(fdp->fd_rdir); newfdp->fd_rdir = fdp->fd_rdir; } /* * If the number of open files fits in the internal arrays * of the open file structure, use them, otherwise allocate * additional memory for the number of descriptors currently * in use. */ if (fdp->fd_lastfile >= NDFILE) { /* * Compute the smallest multiple of NDEXTENT needed * for the file descriptors currently in use, * allowing the table to shrink. */ i = fdp->fd_nfiles; while (i >= 2 * NDEXTENT && i > fdp->fd_lastfile * 2) i /= 2; newfdp->fd_ofiles = mallocarray(i, OFILESIZE, M_FILEDESC, M_WAITOK | M_ZERO); newfdp->fd_ofileflags = (char *) &newfdp->fd_ofiles[i]; newfdp->fd_nfiles = i; } if (NDHISLOTS(newfdp->fd_nfiles) > NDHISLOTS(NDFILE)) { newfdp->fd_himap = mallocarray(NDHISLOTS(newfdp->fd_nfiles), sizeof(u_int), M_FILEDESC, M_WAITOK | M_ZERO); newfdp->fd_lomap = mallocarray(NDLOSLOTS(newfdp->fd_nfiles), sizeof(u_int), M_FILEDESC, M_WAITOK | M_ZERO); } newfdp->fd_freefile = fdp->fd_freefile; newfdp->fd_flags = fdp->fd_flags; newfdp->fd_cmask = fdp->fd_cmask; for (i = 0; i <= fdp->fd_lastfile; i++) { struct file *fp = fdp->fd_ofiles[i]; if (fp != NULL) { /* * XXX Gruesome hack. If count gets too high, fail * to copy an fd, since fdcopy()'s callers do not * permit it to indicate failure yet. * Meanwhile, kqueue files have to be * tied to the process that opened them to enforce * their internal consistency, so close them here. */ if (fp->f_count >= FDUP_MAX_COUNT || fp->f_type == DTYPE_KQUEUE) { if (i < newfdp->fd_freefile) newfdp->fd_freefile = i; continue; } FREF(fp); newfdp->fd_ofiles[i] = fp; newfdp->fd_ofileflags[i] = fdp->fd_ofileflags[i]; fd_used(newfdp, i); } } fdpunlock(fdp); return (newfdp); } /* * Release a filedesc structure. */ void fdfree(struct proc *p) { struct filedesc *fdp = p->p_fd; struct file *fp; int fd; if (--fdp->fd_refcnt > 0) return; for (fd = 0; fd <= fdp->fd_lastfile; fd++) { fp = fdp->fd_ofiles[fd]; if (fp != NULL) { fdp->fd_ofiles[fd] = NULL; knote_fdclose(p, fd); /* closef() expects a refcount of 2 */ FREF(fp); (void) closef(fp, p); } } p->p_fd = NULL; if (fdp->fd_nfiles > NDFILE) free(fdp->fd_ofiles, M_FILEDESC, fdp->fd_nfiles * OFILESIZE); if (NDHISLOTS(fdp->fd_nfiles) > NDHISLOTS(NDFILE)) { free(fdp->fd_himap, M_FILEDESC, NDHISLOTS(fdp->fd_nfiles) * sizeof(u_int)); free(fdp->fd_lomap, M_FILEDESC, NDLOSLOTS(fdp->fd_nfiles) * sizeof(u_int)); } if (fdp->fd_cdir) vrele(fdp->fd_cdir); if (fdp->fd_rdir) vrele(fdp->fd_rdir); pool_put(&fdesc_pool, fdp); } /* * Internal form of close. * Decrement reference count on file structure. * Note: p may be NULL when closing a file * that was being passed in a message. * * The fp must have its usecount bumped and will be FRELEd here. */ int closef(struct file *fp, struct proc *p) { struct filedesc *fdp; if (fp == NULL) return (0); KASSERTMSG(fp->f_count >= 2, "count (%u) < 2", fp->f_count); atomic_dec_int(&fp->f_count); /* * POSIX record locking dictates that any close releases ALL * locks owned by this process. This is handled by setting * a flag in the unlock to free ONLY locks obeying POSIX * semantics, and not to free BSD-style file locks. * If the descriptor was in a message, POSIX-style locks * aren't passed with the descriptor. */ if (p && ((fdp = p->p_fd) != NULL) && (fdp->fd_flags & FD_ADVLOCK) && fp->f_type == DTYPE_VNODE) { struct vnode *vp = fp->f_data; struct flock lf; lf.l_whence = SEEK_SET; lf.l_start = 0; lf.l_len = 0; lf.l_type = F_UNLCK; (void) VOP_ADVLOCK(vp, fdp, F_UNLCK, &lf, F_POSIX); } return (FRELE(fp, p)); } int fdrop(struct file *fp, struct proc *p) { int error; KASSERTMSG(fp->f_count == 0, "count (%u) != 0", fp->f_count); mtx_enter(&fhdlk); if (fp->f_iflags & FIF_INSERTED) LIST_REMOVE(fp, f_list); mtx_leave(&fhdlk); if (fp->f_ops) error = (*fp->f_ops->fo_close)(fp, p); else error = 0; crfree(fp->f_cred); atomic_dec_int(&numfiles); pool_put(&file_pool, fp); return (error); } /* * Apply an advisory lock on a file descriptor. * * Just attempt to get a record lock of the requested type on * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0). */ int sys_flock(struct proc *p, void *v, register_t *retval) { struct sys_flock_args /* { syscallarg(int) fd; syscallarg(int) how; } */ *uap = v; int fd = SCARG(uap, fd); int how = SCARG(uap, how); struct filedesc *fdp = p->p_fd; struct file *fp; struct vnode *vp; struct flock lf; int error; if ((fp = fd_getfile(fdp, fd)) == NULL) return (EBADF); if (fp->f_type != DTYPE_VNODE) { error = EOPNOTSUPP; goto out; } vp = fp->f_data; lf.l_whence = SEEK_SET; lf.l_start = 0; lf.l_len = 0; if (how & LOCK_UN) { lf.l_type = F_UNLCK; atomic_clearbits_int(&fp->f_iflags, FIF_HASLOCK); error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK); goto out; } if (how & LOCK_EX) lf.l_type = F_WRLCK; else if (how & LOCK_SH) lf.l_type = F_RDLCK; else { error = EINVAL; goto out; } atomic_setbits_int(&fp->f_iflags, FIF_HASLOCK); if (how & LOCK_NB) error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK); else error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK|F_WAIT); out: FRELE(fp, p); return (error); } /* * File Descriptor pseudo-device driver (/dev/fd/). * * Opening minor device N dup()s the file (if any) connected to file * descriptor N belonging to the calling process. Note that this driver * consists of only the ``open()'' routine, because all subsequent * references to this file will be direct to the other driver. */ int filedescopen(dev_t dev, int mode, int type, struct proc *p) { /* * XXX Kludge: set curproc->p_dupfd to contain the value of the * the file descriptor being sought for duplication. The error * return ensures that the vnode for this device will be released * by vn_open. Open will detect this special error and take the * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN * will simply report the error. */ p->p_dupfd = minor(dev); return (ENODEV); } /* * Duplicate the specified descriptor to a free descriptor. */ int dupfdopen(struct proc *p, int indx, int mode) { struct filedesc *fdp = p->p_fd; int dupfd = p->p_dupfd; struct file *wfp; fdpassertlocked(fdp); /* * Assume that the filename was user-specified; applications do * not tend to open /dev/fd/# when they can just call dup() */ if ((p->p_p->ps_flags & (PS_SUGIDEXEC | PS_SUGID))) { if (p->p_descfd == 255) return (EPERM); if (p->p_descfd != dupfd) return (EPERM); } /* * If the to-be-dup'd fd number is greater than the allowed number * of file descriptors, or the fd to be dup'd has already been * closed, reject. Note, there is no need to check for new == old * because fd_getfile will return NULL if the file at indx is * newly created by falloc. */ if ((wfp = fd_getfile(fdp, dupfd)) == NULL) return (EBADF); /* * Check that the mode the file is being opened for is a * subset of the mode of the existing descriptor. */ if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) { FRELE(wfp, p); return (EACCES); } if (wfp->f_count >= FDUP_MAX_COUNT) { FRELE(wfp, p); return (EDEADLK); } KASSERT(wfp->f_iflags & FIF_INSERTED); mtx_enter(&fdp->fd_fplock); KASSERT(fdp->fd_ofiles[indx] == NULL); fdp->fd_ofiles[indx] = wfp; mtx_leave(&fdp->fd_fplock); fdp->fd_ofileflags[indx] = (fdp->fd_ofileflags[indx] & UF_EXCLOSE) | (fdp->fd_ofileflags[dupfd] & ~UF_EXCLOSE); return (0); } /* * Close any files on exec? */ void fdcloseexec(struct proc *p) { struct filedesc *fdp = p->p_fd; int fd; fdplock(fdp); for (fd = 0; fd <= fdp->fd_lastfile; fd++) { fdp->fd_ofileflags[fd] &= ~UF_PLEDGED; if (fdp->fd_ofileflags[fd] & UF_EXCLOSE) { /* fdrelease() unlocks fdp. */ (void) fdrelease(p, fd); fdplock(fdp); } } fdpunlock(fdp); } int sys_closefrom(struct proc *p, void *v, register_t *retval) { struct sys_closefrom_args *uap = v; struct filedesc *fdp = p->p_fd; u_int startfd, i; startfd = SCARG(uap, fd); fdplock(fdp); if (startfd > fdp->fd_lastfile) { fdpunlock(fdp); return (EBADF); } for (i = startfd; i <= fdp->fd_lastfile; i++) { /* fdrelease() unlocks fdp. */ fdrelease(p, i); fdplock(fdp); } fdpunlock(fdp); return (0); } int sys_getdtablecount(struct proc *p, void *v, register_t *retval) { *retval = p->p_fd->fd_openfd; return (0); }