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38 * @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94
39 * $FreeBSD: src/sys/kern/kern_descrip.c,v 1.81.2.17 2003/06/06 20:21:32 tegge Exp $
40 * $DragonFly: src/sys/kern/kern_descrip.c,v 1.17 2003/10/21 01:05:09 daver Exp $
43 #include "opt_compat.h"
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/malloc.h>
47 #include <sys/sysproto.h>
49 #include <sys/filedesc.h>
50 #include <sys/kernel.h>
51 #include <sys/sysctl.h>
52 #include <sys/vnode.h>
54 #include <sys/namei.h>
57 #include <sys/filio.h>
58 #include <sys/fcntl.h>
59 #include <sys/unistd.h>
60 #include <sys/resourcevar.h>
61 #include <sys/event.h>
62 #include <sys/kern_syscall.h>
65 #include <vm/vm_extern.h>
67 #include <sys/file2.h>
69 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table");
70 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader",
71 "file desc to leader structures");
72 MALLOC_DEFINE(M_FILE, "file", "Open file structure");
73 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures");
75 static d_open_t fdopen;
79 static struct cdevsw fildesc_cdevsw = {
93 /* strategy */ nostrategy,
98 static int badfo_readwrite (struct file *fp, struct uio *uio,
99 struct ucred *cred, int flags, struct thread *td);
100 static int badfo_ioctl (struct file *fp, u_long com, caddr_t data,
102 static int badfo_poll (struct file *fp, int events,
103 struct ucred *cred, struct thread *td);
104 static int badfo_kqfilter (struct file *fp, struct knote *kn);
105 static int badfo_stat (struct file *fp, struct stat *sb, struct thread *td);
106 static int badfo_close (struct file *fp, struct thread *td);
109 * Descriptor management.
111 struct filelist filehead; /* head of list of open files */
112 int nfiles; /* actual number of open files */
116 * System calls on descriptors.
120 getdtablesize(struct getdtablesize_args *uap)
122 struct proc *p = curproc;
125 min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
130 * Duplicate a file descriptor to a particular value.
132 * note: keep in mind that a potential race condition exists when closing
133 * descriptors from a shared descriptor table (via rfork).
137 dup2(struct dup2_args *uap)
141 error = kern_dup(DUP_FIXED, uap->from, uap->to, uap->sysmsg_fds);
147 * Duplicate a file descriptor.
151 dup(struct dup_args *uap)
155 error = kern_dup(DUP_VARIABLE, uap->fd, 0, uap->sysmsg_fds);
161 kern_fcntl(int fd, int cmd, union fcntl_dat *dat)
163 struct thread *td = curthread;
164 struct proc *p = td->td_proc;
165 struct filedesc *fdp = p->p_fd;
170 int tmp, error, flg = F_POSIX;
174 if ((unsigned)fd >= fdp->fd_nfiles ||
175 (fp = fdp->fd_ofiles[fd]) == NULL)
177 pop = &fdp->fd_ofileflags[fd];
182 if (newmin >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
183 newmin > maxfilesperproc)
185 error = kern_dup(DUP_VARIABLE, fd, newmin, &dat->fc_fd);
189 dat->fc_cloexec = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0;
193 *pop = (*pop &~ UF_EXCLOSE) |
194 (dat->fc_cloexec & FD_CLOEXEC ? UF_EXCLOSE : 0);
198 dat->fc_flags = OFLAGS(fp->f_flag);
203 fp->f_flag &= ~FCNTLFLAGS;
204 fp->f_flag |= FFLAGS(dat->fc_flags & ~O_ACCMODE) & FCNTLFLAGS;
205 tmp = fp->f_flag & FNONBLOCK;
206 error = fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, td);
211 tmp = fp->f_flag & FASYNC;
212 error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, td);
217 fp->f_flag &= ~FNONBLOCK;
219 fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, td);
225 error = fo_ioctl(fp, FIOGETOWN, (caddr_t)&dat->fc_owner, td);
231 error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&dat->fc_owner, td);
237 /* Fall into F_SETLK */
240 if (fp->f_type != DTYPE_VNODE)
242 vp = (struct vnode *)fp->f_data;
245 * copyin/lockop may block
248 if (dat->fc_flock.l_whence == SEEK_CUR)
249 dat->fc_flock.l_start += fp->f_offset;
251 switch (dat->fc_flock.l_type) {
253 if ((fp->f_flag & FREAD) == 0) {
257 p->p_leader->p_flag |= P_ADVLOCK;
258 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
259 &dat->fc_flock, flg);
262 if ((fp->f_flag & FWRITE) == 0) {
266 p->p_leader->p_flag |= P_ADVLOCK;
267 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
268 &dat->fc_flock, flg);
271 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
272 &dat->fc_flock, F_POSIX);
278 /* Check for race with close */
279 if ((unsigned) fd >= fdp->fd_nfiles ||
280 fp != fdp->fd_ofiles[fd]) {
281 dat->fc_flock.l_whence = SEEK_SET;
282 dat->fc_flock.l_start = 0;
283 dat->fc_flock.l_len = 0;
284 dat->fc_flock.l_type = F_UNLCK;
285 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader,
286 F_UNLCK, &dat->fc_flock, F_POSIX);
292 if (fp->f_type != DTYPE_VNODE)
294 vp = (struct vnode *)fp->f_data;
296 * copyin/lockop may block
299 if (dat->fc_flock.l_type != F_RDLCK &&
300 dat->fc_flock.l_type != F_WRLCK &&
301 dat->fc_flock.l_type != F_UNLCK) {
305 if (dat->fc_flock.l_whence == SEEK_CUR)
306 dat->fc_flock.l_start += fp->f_offset;
307 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK,
308 &dat->fc_flock, F_POSIX);
318 * The file control system call.
321 fcntl(struct fcntl_args *uap)
328 dat.fc_fd = uap->arg;
331 dat.fc_cloexec = uap->arg;
334 dat.fc_flags = uap->arg;
337 dat.fc_owner = uap->arg;
342 error = copyin((caddr_t)uap->arg, &dat.fc_flock,
343 sizeof(struct flock));
349 error = kern_fcntl(uap->fd, uap->cmd, &dat);
354 uap->sysmsg_result = dat.fc_fd;
357 uap->sysmsg_result = dat.fc_cloexec;
360 uap->sysmsg_result = dat.fc_flags;
363 uap->sysmsg_result = dat.fc_owner;
365 error = copyout(&dat.fc_flock, (caddr_t)uap->arg,
366 sizeof(struct flock));
375 * Common code for dup, dup2, and fcntl(F_DUPFD).
377 * The type flag can be either DUP_FIXED or DUP_VARIABLE. DUP_FIXED tells
378 * kern_dup() to destructively dup over an existing file descriptor if new
379 * is already open. DUP_VARIABLE tells kern_dup() to find the lowest
380 * unused file descriptor that is greater than or equal to new.
383 kern_dup(enum dup_type type, int old, int new, int *res)
385 struct thread *td = curthread;
386 struct proc *p = td->td_proc;
387 struct filedesc *fdp = p->p_fd;
394 * Verify that we have a valid descriptor to dup from and
395 * possibly to dup to.
397 if (old < 0 || new < 0 || new > p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
398 new >= maxfilesperproc)
400 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL)
402 if (type == DUP_FIXED && old == new) {
406 fp = fdp->fd_ofiles[old];
410 * Expand the table for the new descriptor if needed. This may
411 * block and drop and reacquire the fidedesc lock.
413 if (type == DUP_VARIABLE || new >= fdp->fd_nfiles) {
414 error = fdalloc(p, new, &newfd);
420 if (type == DUP_VARIABLE)
424 * If the old file changed out from under us then treat it as a
425 * bad file descriptor. Userland should do its own locking to
428 if (fdp->fd_ofiles[old] != fp) {
429 if (fdp->fd_ofiles[new] == NULL) {
430 if (new < fdp->fd_freefile)
431 fdp->fd_freefile = new;
432 while (fdp->fd_lastfile > 0 &&
433 fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
439 KASSERT(old != new, ("new fd is same as old"));
442 * Save info on the descriptor being overwritten. We have
443 * to do the unmap now, but we cannot close it without
444 * introducing an ownership race for the slot.
446 delfp = fdp->fd_ofiles[new];
447 if (delfp != NULL && p->p_fdtol != NULL) {
449 * Ask fdfree() to sleep to ensure that all relevant
450 * process leaders can be traversed in closef().
452 fdp->fd_holdleaderscount++;
456 KASSERT(delfp == NULL || type == DUP_FIXED,
457 ("dup() picked an open file"));
459 if (delfp && (fdp->fd_ofileflags[new] & UF_MAPPED))
460 (void) munmapfd(p, new);
464 * Duplicate the source descriptor, update lastfile
466 fdp->fd_ofiles[new] = fp;
467 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE;
468 if (new > fdp->fd_lastfile)
469 fdp->fd_lastfile = new;
473 * If we dup'd over a valid file, we now own the reference to it
474 * and must dispose of it using closef() semantics (as if a
475 * close() were performed on it).
478 (void) closef(delfp, td);
480 fdp->fd_holdleaderscount--;
481 if (fdp->fd_holdleaderscount == 0 &&
482 fdp->fd_holdleaderswakeup != 0) {
483 fdp->fd_holdleaderswakeup = 0;
484 wakeup(&fdp->fd_holdleaderscount);
492 * If sigio is on the list associated with a process or process group,
493 * disable signalling from the device, remove sigio from the list and
505 *(sigio->sio_myref) = NULL;
507 if (sigio->sio_pgid < 0) {
508 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio,
510 } else /* if ((*sigiop)->sio_pgid > 0) */ {
511 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio,
514 crfree(sigio->sio_ucred);
515 FREE(sigio, M_SIGIO);
518 /* Free a list of sigio structures. */
520 funsetownlst(sigiolst)
521 struct sigiolst *sigiolst;
525 while ((sigio = SLIST_FIRST(sigiolst)) != NULL)
530 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg).
532 * After permission checking, add a sigio structure to the sigio list for
533 * the process or process group.
536 fsetown(pgid, sigiop)
538 struct sigio **sigiop;
555 * Policy - Don't allow a process to FSETOWN a process
556 * in another session.
558 * Remove this test to allow maximum flexibility or
559 * restrict FSETOWN to the current process or process
560 * group for maximum safety.
562 if (proc->p_session != curproc->p_session)
566 } else /* if (pgid < 0) */ {
567 pgrp = pgfind(-pgid);
572 * Policy - Don't allow a process to FSETOWN a process
573 * in another session.
575 * Remove this test to allow maximum flexibility or
576 * restrict FSETOWN to the current process or process
577 * group for maximum safety.
579 if (pgrp->pg_session != curproc->p_session)
585 MALLOC(sigio, struct sigio *, sizeof(struct sigio), M_SIGIO, M_WAITOK);
587 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio);
588 sigio->sio_proc = proc;
590 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
591 sigio->sio_pgrp = pgrp;
593 sigio->sio_pgid = pgid;
594 sigio->sio_ucred = crhold(curproc->p_ucred);
595 /* It would be convenient if p_ruid was in ucred. */
596 sigio->sio_ruid = curproc->p_ucred->cr_ruid;
597 sigio->sio_myref = sigiop;
605 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg).
611 return (sigio != NULL ? sigio->sio_pgid : 0);
615 * Close a file descriptor.
619 close(struct close_args *uap)
621 struct thread *td = curthread;
622 struct proc *p = td->td_proc;
623 struct filedesc *fdp;
632 if ((unsigned)fd >= fdp->fd_nfiles ||
633 (fp = fdp->fd_ofiles[fd]) == NULL)
636 if (fdp->fd_ofileflags[fd] & UF_MAPPED)
637 (void) munmapfd(p, fd);
639 fdp->fd_ofiles[fd] = NULL;
640 fdp->fd_ofileflags[fd] = 0;
642 if (p->p_fdtol != NULL) {
644 * Ask fdfree() to sleep to ensure that all relevant
645 * process leaders can be traversed in closef().
647 fdp->fd_holdleaderscount++;
652 * we now hold the fp reference that used to be owned by the descriptor
655 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
657 if (fd < fdp->fd_freefile)
658 fdp->fd_freefile = fd;
659 if (fd < fdp->fd_knlistsize)
660 knote_fdclose(p, fd);
661 error = closef(fp, td);
663 fdp->fd_holdleaderscount--;
664 if (fdp->fd_holdleaderscount == 0 &&
665 fdp->fd_holdleaderswakeup != 0) {
666 fdp->fd_holdleaderswakeup = 0;
667 wakeup(&fdp->fd_holdleaderscount);
674 kern_fstat(int fd, struct stat *ub)
676 struct thread *td = curthread;
677 struct proc *p = td->td_proc;
678 struct filedesc *fdp;
685 if ((unsigned)fd >= fdp->fd_nfiles ||
686 (fp = fdp->fd_ofiles[fd]) == NULL)
689 error = fo_stat(fp, ub, td);
696 * Return status information about a file descriptor.
699 fstat(struct fstat_args *uap)
704 error = kern_fstat(uap->fd, &st);
707 error = copyout(&st, uap->sb, sizeof(st));
712 * XXX: This is for source compatibility with NetBSD. Probably doesn't
716 nfstat(struct nfstat_args *uap)
722 error = kern_fstat(uap->fd, &st);
726 error = copyout(&nst, uap->sb, sizeof (nst));
732 * Return pathconf information about a file descriptor.
736 fpathconf(struct fpathconf_args *uap)
738 struct thread *td = curthread;
739 struct proc *p = td->td_proc;
740 struct filedesc *fdp;
747 if ((unsigned)uap->fd >= fdp->fd_nfiles ||
748 (fp = fdp->fd_ofiles[uap->fd]) == NULL)
753 switch (fp->f_type) {
756 if (uap->name != _PC_PIPE_BUF) {
759 uap->sysmsg_result = PIPE_BUF;
765 vp = (struct vnode *)fp->f_data;
766 error = VOP_PATHCONF(vp, uap->name, uap->sysmsg_fds);
777 * Allocate a file descriptor for the process.
780 SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, "");
783 fdalloc(struct proc *p, int want, int *result)
785 struct filedesc *fdp = p->p_fd;
787 int lim, last, nfiles;
788 struct file **newofile;
792 * Search for a free descriptor starting at the higher
793 * of want or fd_freefile. If that fails, consider
794 * expanding the ofile array.
796 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
798 last = min(fdp->fd_nfiles, lim);
799 if ((i = want) < fdp->fd_freefile)
800 i = fdp->fd_freefile;
801 for (; i < last; i++) {
802 if (fdp->fd_ofiles[i] == NULL) {
803 fdp->fd_ofileflags[i] = 0;
804 if (i > fdp->fd_lastfile)
805 fdp->fd_lastfile = i;
806 if (want <= fdp->fd_freefile)
807 fdp->fd_freefile = i;
814 * No space in current array. Expand?
816 if (fdp->fd_nfiles >= lim)
818 if (fdp->fd_nfiles < NDEXTENT)
821 nfiles = 2 * fdp->fd_nfiles;
822 MALLOC(newofile, struct file **, nfiles * OFILESIZE,
823 M_FILEDESC, M_WAITOK);
826 * deal with file-table extend race that might have occured
827 * when malloc was blocked.
829 if (fdp->fd_nfiles >= nfiles) {
830 FREE(newofile, M_FILEDESC);
833 newofileflags = (char *) &newofile[nfiles];
835 * Copy the existing ofile and ofileflags arrays
836 * and zero the new portion of each array.
838 bcopy(fdp->fd_ofiles, newofile,
839 (i = sizeof(struct file *) * fdp->fd_nfiles));
840 bzero((char *)newofile + i, nfiles * sizeof(struct file *) - i);
841 bcopy(fdp->fd_ofileflags, newofileflags,
842 (i = sizeof(char) * fdp->fd_nfiles));
843 bzero(newofileflags + i, nfiles * sizeof(char) - i);
844 if (fdp->fd_nfiles > NDFILE)
845 FREE(fdp->fd_ofiles, M_FILEDESC);
846 fdp->fd_ofiles = newofile;
847 fdp->fd_ofileflags = newofileflags;
848 fdp->fd_nfiles = nfiles;
855 * Check to see whether n user file descriptors
856 * are available to the process p.
863 struct filedesc *fdp = p->p_fd;
867 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
868 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0)
871 last = min(fdp->fd_nfiles, lim);
872 fpp = &fdp->fd_ofiles[fdp->fd_freefile];
873 for (i = last - fdp->fd_freefile; --i >= 0; fpp++) {
874 if (*fpp == NULL && --n <= 0)
882 * Create a new open file structure and allocate a file decriptor
883 * for the process that refers to it. If p is NULL, no descriptor
884 * is allocated and the file pointer is returned unassociated with
885 * any process. resultfd is only used if p is not NULL and may
886 * separately be NULL indicating that you don't need the returned fd.
889 falloc(struct proc *p, struct file **resultfp, int *resultfd)
891 struct file *fp, *fq;
894 if (nfiles >= maxfiles) {
899 * Allocate a new file descriptor.
900 * If the process has file descriptor zero open, add to the list
901 * of open files at that point, otherwise put it at the front of
902 * the list of open files.
905 MALLOC(fp, struct file *, sizeof(struct file), M_FILE, M_WAITOK);
906 bzero(fp, sizeof(struct file));
909 * wait until after malloc (which may have blocked) returns before
910 * allocating the slot, else a race might have shrunk it if we had
911 * allocated it before the malloc.
914 if (p && (error = fdalloc(p, 0, &i))) {
920 fp->f_ops = &badfileops;
923 fp->f_cred = crhold(p->p_ucred);
924 if ((fq = p->p_fd->fd_ofiles[0]) != NULL) {
925 LIST_INSERT_AFTER(fq, fp, f_list);
927 LIST_INSERT_HEAD(&filehead, fp, f_list);
929 p->p_fd->fd_ofiles[i] = fp;
931 fp->f_cred = crhold(proc0.p_ucred);
932 LIST_INSERT_HEAD(&filehead, fp, f_list);
942 fsetcred(struct file *fp, struct ucred *cr)
950 * Free a file descriptor.
956 KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!"));
957 LIST_REMOVE(fp, f_list);
964 * Build a new filedesc structure.
970 struct filedesc0 *newfdp;
971 struct filedesc *fdp = p->p_fd;
973 MALLOC(newfdp, struct filedesc0 *, sizeof(struct filedesc0),
974 M_FILEDESC, M_WAITOK);
975 bzero(newfdp, sizeof(struct filedesc0));
976 newfdp->fd_fd.fd_cdir = fdp->fd_cdir;
977 if (newfdp->fd_fd.fd_cdir)
978 VREF(newfdp->fd_fd.fd_cdir);
979 newfdp->fd_fd.fd_rdir = fdp->fd_rdir;
980 if (newfdp->fd_fd.fd_rdir)
981 VREF(newfdp->fd_fd.fd_rdir);
982 newfdp->fd_fd.fd_jdir = fdp->fd_jdir;
983 if (newfdp->fd_fd.fd_jdir)
984 VREF(newfdp->fd_fd.fd_jdir);
986 /* Create the file descriptor table. */
987 newfdp->fd_fd.fd_refcnt = 1;
988 newfdp->fd_fd.fd_cmask = cmask;
989 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles;
990 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags;
991 newfdp->fd_fd.fd_nfiles = NDFILE;
992 newfdp->fd_fd.fd_knlistsize = -1;
994 return (&newfdp->fd_fd);
998 * Share a filedesc structure.
1004 p->p_fd->fd_refcnt++;
1009 * Copy a filedesc structure.
1015 struct filedesc *newfdp, *fdp = p->p_fd;
1019 /* Certain daemons might not have file descriptors. */
1023 MALLOC(newfdp, struct filedesc *, sizeof(struct filedesc0),
1024 M_FILEDESC, M_WAITOK);
1025 bcopy(fdp, newfdp, sizeof(struct filedesc));
1026 if (newfdp->fd_cdir)
1027 VREF(newfdp->fd_cdir);
1028 if (newfdp->fd_rdir)
1029 VREF(newfdp->fd_rdir);
1030 if (newfdp->fd_jdir)
1031 VREF(newfdp->fd_jdir);
1032 newfdp->fd_refcnt = 1;
1035 * If the number of open files fits in the internal arrays
1036 * of the open file structure, use them, otherwise allocate
1037 * additional memory for the number of descriptors currently
1040 if (newfdp->fd_lastfile < NDFILE) {
1041 newfdp->fd_ofiles = ((struct filedesc0 *) newfdp)->fd_dfiles;
1042 newfdp->fd_ofileflags =
1043 ((struct filedesc0 *) newfdp)->fd_dfileflags;
1047 * Compute the smallest multiple of NDEXTENT needed
1048 * for the file descriptors currently in use,
1049 * allowing the table to shrink.
1051 i = newfdp->fd_nfiles;
1052 while (i > 2 * NDEXTENT && i > newfdp->fd_lastfile * 2)
1054 MALLOC(newfdp->fd_ofiles, struct file **, i * OFILESIZE,
1055 M_FILEDESC, M_WAITOK);
1056 newfdp->fd_ofileflags = (char *) &newfdp->fd_ofiles[i];
1058 newfdp->fd_nfiles = i;
1059 bcopy(fdp->fd_ofiles, newfdp->fd_ofiles, i * sizeof(struct file **));
1060 bcopy(fdp->fd_ofileflags, newfdp->fd_ofileflags, i * sizeof(char));
1063 * kq descriptors cannot be copied.
1065 if (newfdp->fd_knlistsize != -1) {
1066 fpp = &newfdp->fd_ofiles[newfdp->fd_lastfile];
1067 for (i = newfdp->fd_lastfile; i >= 0; i--, fpp--) {
1068 if (*fpp != NULL && (*fpp)->f_type == DTYPE_KQUEUE) {
1070 if (i < newfdp->fd_freefile)
1071 newfdp->fd_freefile = i;
1073 if (*fpp == NULL && i == newfdp->fd_lastfile && i > 0)
1074 newfdp->fd_lastfile--;
1076 newfdp->fd_knlist = NULL;
1077 newfdp->fd_knlistsize = -1;
1078 newfdp->fd_knhash = NULL;
1079 newfdp->fd_knhashmask = 0;
1082 fpp = newfdp->fd_ofiles;
1083 for (i = newfdp->fd_lastfile; i-- >= 0; fpp++) {
1091 * Release a filedesc structure.
1094 fdfree(struct proc *p)
1096 struct thread *td = p->p_thread;
1097 struct filedesc *fdp = p->p_fd;
1100 struct filedesc_to_leader *fdtol;
1105 /* Certain daemons might not have file descriptors. */
1109 /* Check for special need to clear POSIX style locks */
1111 if (fdtol != NULL) {
1112 KASSERT(fdtol->fdl_refcount > 0,
1113 ("filedesc_to_refcount botch: fdl_refcount=%d",
1114 fdtol->fdl_refcount));
1115 if (fdtol->fdl_refcount == 1 &&
1116 (p->p_leader->p_flag & P_ADVLOCK) != 0) {
1118 fpp = fdp->fd_ofiles;
1119 for (i = 0, fpp = fdp->fd_ofiles;
1120 i < fdp->fd_lastfile;
1123 (*fpp)->f_type != DTYPE_VNODE)
1127 lf.l_whence = SEEK_SET;
1130 lf.l_type = F_UNLCK;
1131 vp = (struct vnode *)fp->f_data;
1132 (void) VOP_ADVLOCK(vp,
1133 (caddr_t)p->p_leader,
1137 fdrop(fp, p->p_thread);
1138 fpp = fdp->fd_ofiles + i;
1142 if (fdtol->fdl_refcount == 1) {
1143 if (fdp->fd_holdleaderscount > 0 &&
1144 (p->p_leader->p_flag & P_ADVLOCK) != 0) {
1146 * close() or do_dup() has cleared a reference
1147 * in a shared file descriptor table.
1149 fdp->fd_holdleaderswakeup = 1;
1150 tsleep(&fdp->fd_holdleaderscount,
1154 if (fdtol->fdl_holdcount > 0) {
1156 * Ensure that fdtol->fdl_leader
1157 * remains valid in closef().
1159 fdtol->fdl_wakeup = 1;
1160 tsleep(fdtol, 0, "fdlhold", 0);
1164 fdtol->fdl_refcount--;
1165 if (fdtol->fdl_refcount == 0 &&
1166 fdtol->fdl_holdcount == 0) {
1167 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev;
1168 fdtol->fdl_prev->fdl_next = fdtol->fdl_next;
1173 FREE(fdtol, M_FILEDESC_TO_LEADER);
1175 if (--fdp->fd_refcnt > 0)
1178 * we are the last reference to the structure, we can
1179 * safely assume it will not change out from under us.
1181 fpp = fdp->fd_ofiles;
1182 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) {
1184 (void) closef(*fpp, td);
1186 if (fdp->fd_nfiles > NDFILE)
1187 FREE(fdp->fd_ofiles, M_FILEDESC);
1189 vrele(fdp->fd_cdir);
1191 vrele(fdp->fd_rdir);
1193 vrele(fdp->fd_jdir);
1195 FREE(fdp->fd_knlist, M_KQUEUE);
1197 FREE(fdp->fd_knhash, M_KQUEUE);
1198 FREE(fdp, M_FILEDESC);
1202 * For setugid programs, we don't want to people to use that setugidness
1203 * to generate error messages which write to a file which otherwise would
1204 * otherwise be off-limits to the process.
1206 * This is a gross hack to plug the hole. A better solution would involve
1207 * a special vop or other form of generalized access control mechanism. We
1208 * go ahead and just reject all procfs file systems accesses as dangerous.
1210 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is
1211 * sufficient. We also don't for check setugidness since we know we are.
1214 is_unsafe(struct file *fp)
1216 if (fp->f_type == DTYPE_VNODE &&
1217 ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS)
1223 * Make this setguid thing safe, if at all possible.
1226 setugidsafety(struct proc *p)
1228 struct thread *td = p->p_thread;
1229 struct filedesc *fdp = p->p_fd;
1232 /* Certain daemons might not have file descriptors. */
1237 * note: fdp->fd_ofiles may be reallocated out from under us while
1238 * we are blocked in a close. Be careful!
1240 for (i = 0; i <= fdp->fd_lastfile; i++) {
1243 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) {
1247 if ((fdp->fd_ofileflags[i] & UF_MAPPED) != 0)
1248 (void) munmapfd(p, i);
1250 if (i < fdp->fd_knlistsize)
1251 knote_fdclose(p, i);
1253 * NULL-out descriptor prior to close to avoid
1254 * a race while close blocks.
1256 fp = fdp->fd_ofiles[i];
1257 fdp->fd_ofiles[i] = NULL;
1258 fdp->fd_ofileflags[i] = 0;
1259 if (i < fdp->fd_freefile)
1260 fdp->fd_freefile = i;
1261 (void) closef(fp, td);
1264 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
1269 * Close any files on exec?
1272 fdcloseexec(struct proc *p)
1274 struct thread *td = p->p_thread;
1275 struct filedesc *fdp = p->p_fd;
1278 /* Certain daemons might not have file descriptors. */
1283 * We cannot cache fd_ofiles or fd_ofileflags since operations
1284 * may block and rip them out from under us.
1286 for (i = 0; i <= fdp->fd_lastfile; i++) {
1287 if (fdp->fd_ofiles[i] != NULL &&
1288 (fdp->fd_ofileflags[i] & UF_EXCLOSE)) {
1292 if (fdp->fd_ofileflags[i] & UF_MAPPED)
1293 (void) munmapfd(p, i);
1295 if (i < fdp->fd_knlistsize)
1296 knote_fdclose(p, i);
1298 * NULL-out descriptor prior to close to avoid
1299 * a race while close blocks.
1301 fp = fdp->fd_ofiles[i];
1302 fdp->fd_ofiles[i] = NULL;
1303 fdp->fd_ofileflags[i] = 0;
1304 if (i < fdp->fd_freefile)
1305 fdp->fd_freefile = i;
1306 (void) closef(fp, td);
1309 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
1314 * It is unsafe for set[ug]id processes to be started with file
1315 * descriptors 0..2 closed, as these descriptors are given implicit
1316 * significance in the Standard C library. fdcheckstd() will create a
1317 * descriptor referencing /dev/null for each of stdin, stdout, and
1318 * stderr that is not already open.
1321 fdcheckstd(struct proc *p)
1323 struct thread *td = p->p_thread;
1324 struct nameidata nd;
1325 struct filedesc *fdp;
1328 int fd, i, error, flags, devnull;
1335 for (i = 0; i < 3; i++) {
1336 if (fdp->fd_ofiles[i] != NULL)
1339 error = falloc(p, &fp, &fd);
1342 NDINIT(&nd, NAMEI_LOOKUP, CNP_FOLLOW, UIO_SYSSPACE,
1344 flags = FREAD | FWRITE;
1345 error = vn_open(&nd, flags, 0);
1347 fdp->fd_ofiles[i] = NULL;
1351 NDFREE(&nd, NDF_ONLY_PNBUF);
1352 fp->f_data = (caddr_t)nd.ni_vp;
1355 fp->f_type = DTYPE_VNODE;
1356 VOP_UNLOCK(nd.ni_vp, 0, td);
1359 error = kern_dup(DUP_FIXED, devnull, i, &retval);
1368 * Internal form of close.
1369 * Decrement reference count on file structure.
1370 * Note: td and/or p may be NULL when closing a file
1371 * that was being passed in a message.
1374 closef(struct file *fp, struct thread *td)
1378 struct filedesc_to_leader *fdtol;
1385 p = NULL; /* allow no proc association */
1387 p = td->td_proc; /* can also be NULL */
1390 * POSIX record locking dictates that any close releases ALL
1391 * locks owned by this process. This is handled by setting
1392 * a flag in the unlock to free ONLY locks obeying POSIX
1393 * semantics, and not to free BSD-style file locks.
1394 * If the descriptor was in a message, POSIX-style locks
1395 * aren't passed with the descriptor.
1398 fp->f_type == DTYPE_VNODE) {
1399 if ((p->p_leader->p_flag & P_ADVLOCK) != 0) {
1400 lf.l_whence = SEEK_SET;
1403 lf.l_type = F_UNLCK;
1404 vp = (struct vnode *)fp->f_data;
1405 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
1409 if (fdtol != NULL) {
1411 * Handle special case where file descriptor table
1412 * is shared between multiple process leaders.
1414 for (fdtol = fdtol->fdl_next;
1415 fdtol != p->p_fdtol;
1416 fdtol = fdtol->fdl_next) {
1417 if ((fdtol->fdl_leader->p_flag &
1420 fdtol->fdl_holdcount++;
1421 lf.l_whence = SEEK_SET;
1424 lf.l_type = F_UNLCK;
1425 vp = (struct vnode *)fp->f_data;
1426 (void) VOP_ADVLOCK(vp,
1427 (caddr_t)p->p_leader,
1428 F_UNLCK, &lf, F_POSIX);
1429 fdtol->fdl_holdcount--;
1430 if (fdtol->fdl_holdcount == 0 &&
1431 fdtol->fdl_wakeup != 0) {
1432 fdtol->fdl_wakeup = 0;
1438 return (fdrop(fp, td));
1442 fdrop(struct file *fp, struct thread *td)
1448 if (--fp->f_count > 0)
1450 if (fp->f_count < 0)
1451 panic("fdrop: count < 0");
1452 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) {
1453 lf.l_whence = SEEK_SET;
1456 lf.l_type = F_UNLCK;
1457 vp = (struct vnode *)fp->f_data;
1458 (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
1460 if (fp->f_ops != &badfileops)
1461 error = fo_close(fp, td);
1469 * Apply an advisory lock on a file descriptor.
1471 * Just attempt to get a record lock of the requested type on
1472 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0).
1476 flock(struct flock_args *uap)
1478 struct proc *p = curproc;
1479 struct filedesc *fdp = p->p_fd;
1484 if ((unsigned)uap->fd >= fdp->fd_nfiles ||
1485 (fp = fdp->fd_ofiles[uap->fd]) == NULL)
1487 if (fp->f_type != DTYPE_VNODE)
1488 return (EOPNOTSUPP);
1489 vp = (struct vnode *)fp->f_data;
1490 lf.l_whence = SEEK_SET;
1493 if (uap->how & LOCK_UN) {
1494 lf.l_type = F_UNLCK;
1495 fp->f_flag &= ~FHASLOCK;
1496 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK));
1498 if (uap->how & LOCK_EX)
1499 lf.l_type = F_WRLCK;
1500 else if (uap->how & LOCK_SH)
1501 lf.l_type = F_RDLCK;
1504 fp->f_flag |= FHASLOCK;
1505 if (uap->how & LOCK_NB)
1506 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK));
1507 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK|F_WAIT));
1511 * File Descriptor pseudo-device driver (/dev/fd/).
1513 * Opening minor device N dup()s the file (if any) connected to file
1514 * descriptor N belonging to the calling process. Note that this driver
1515 * consists of only the ``open()'' routine, because all subsequent
1516 * references to this file will be direct to the other driver.
1520 fdopen(dev_t dev, int mode, int type, struct thread *td)
1522 KKASSERT(td->td_proc != NULL);
1525 * XXX Kludge: set curproc->p_dupfd to contain the value of the
1526 * the file descriptor being sought for duplication. The error
1527 * return ensures that the vnode for this device will be released
1528 * by vn_open. Open will detect this special error and take the
1529 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
1530 * will simply report the error.
1532 td->td_proc->p_dupfd = minor(dev);
1537 * Duplicate the specified descriptor to a free descriptor.
1540 dupfdopen(struct filedesc *fdp, int indx, int dfd, int mode, int error)
1546 * If the to-be-dup'd fd number is greater than the allowed number
1547 * of file descriptors, or the fd to be dup'd has already been
1548 * closed, then reject.
1550 if ((u_int)dfd >= fdp->fd_nfiles ||
1551 (wfp = fdp->fd_ofiles[dfd]) == NULL) {
1556 * There are two cases of interest here.
1558 * For ENODEV simply dup (dfd) to file descriptor
1559 * (indx) and return.
1561 * For ENXIO steal away the file structure from (dfd) and
1562 * store it in (indx). (dfd) is effectively closed by
1565 * Any other error code is just returned.
1570 * Check that the mode the file is being opened for is a
1571 * subset of the mode of the existing descriptor.
1573 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag)
1575 fp = fdp->fd_ofiles[indx];
1577 if (fp && fdp->fd_ofileflags[indx] & UF_MAPPED)
1578 (void) munmapfd(p, indx);
1580 fdp->fd_ofiles[indx] = wfp;
1581 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
1583 if (indx > fdp->fd_lastfile)
1584 fdp->fd_lastfile = indx;
1586 * we now own the reference to fp that the ofiles[] array
1587 * used to own. Release it.
1590 fdrop(fp, curthread);
1595 * Steal away the file pointer from dfd, and stuff it into indx.
1597 fp = fdp->fd_ofiles[indx];
1599 if (fp && fdp->fd_ofileflags[indx] & UF_MAPPED)
1600 (void) munmapfd(p, indx);
1602 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd];
1603 fdp->fd_ofiles[dfd] = NULL;
1604 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
1605 fdp->fd_ofileflags[dfd] = 0;
1608 * we now own the reference to fp that the ofiles[] array
1609 * used to own. Release it.
1612 fdrop(fp, curthread);
1614 * Complete the clean up of the filedesc structure by
1615 * recomputing the various hints.
1617 if (indx > fdp->fd_lastfile) {
1618 fdp->fd_lastfile = indx;
1620 while (fdp->fd_lastfile > 0 &&
1621 fdp->fd_ofiles[fdp->fd_lastfile] == NULL) {
1624 if (dfd < fdp->fd_freefile)
1625 fdp->fd_freefile = dfd;
1636 struct filedesc_to_leader *
1637 filedesc_to_leader_alloc(struct filedesc_to_leader *old,
1638 struct proc *leader)
1640 struct filedesc_to_leader *fdtol;
1642 MALLOC(fdtol, struct filedesc_to_leader *,
1643 sizeof(struct filedesc_to_leader),
1644 M_FILEDESC_TO_LEADER,
1646 fdtol->fdl_refcount = 1;
1647 fdtol->fdl_holdcount = 0;
1648 fdtol->fdl_wakeup = 0;
1649 fdtol->fdl_leader = leader;
1651 fdtol->fdl_next = old->fdl_next;
1652 fdtol->fdl_prev = old;
1653 old->fdl_next = fdtol;
1654 fdtol->fdl_next->fdl_prev = fdtol;
1656 fdtol->fdl_next = fdtol;
1657 fdtol->fdl_prev = fdtol;
1663 * Get file structures.
1666 sysctl_kern_file(SYSCTL_HANDLER_ARGS)
1673 * overestimate by 10 files
1675 return (SYSCTL_OUT(req, 0, sizeof(filehead) +
1676 (nfiles + 10) * sizeof(struct file)));
1679 error = SYSCTL_OUT(req, (caddr_t)&filehead, sizeof(filehead));
1684 * followed by an array of file structures
1686 LIST_FOREACH(fp, &filehead, f_list) {
1687 error = SYSCTL_OUT(req, (caddr_t)fp, sizeof (struct file));
1694 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD,
1695 0, 0, sysctl_kern_file, "S,file", "Entire file table");
1697 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW,
1698 &maxfilesperproc, 0, "Maximum files allowed open per process");
1700 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW,
1701 &maxfiles, 0, "Maximum number of files");
1703 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD,
1704 &nfiles, 0, "System-wide number of open files");
1707 fildesc_drvinit(void *unused)
1711 for (fd = 0; fd < NUMFDESC; fd++)
1712 make_dev(&fildesc_cdevsw, fd,
1713 UID_BIN, GID_BIN, 0666, "fd/%d", fd);
1714 make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "stdin");
1715 make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "stdout");
1716 make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "stderr");
1719 struct fileops badfileops = {
1743 badfo_ioctl(struct file *fp, u_long com, caddr_t data, struct thread *td)
1749 badfo_poll(struct file *fp, int events, struct ucred *cred, struct thread *td)
1755 badfo_kqfilter(struct file *fp, struct knote *kn)
1761 badfo_stat(struct file *fp, struct stat *sb, struct thread *td)
1767 badfo_close(struct file *fp, struct thread *td)
1772 SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,
1773 fildesc_drvinit,NULL)