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38 * @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94
39 * $FreeBSD: src/sys/kern/kern_descrip.c,v 1.81.2.19 2004/02/28 00:43:31 tegge Exp $
40 * $DragonFly: src/sys/kern/kern_descrip.c,v 1.41 2005/04/08 17:39:31 joerg 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/nlookup.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>
63 #include <sys/kcore.h>
64 #include <sys/kinfo.h>
67 #include <vm/vm_extern.h>
69 #include <sys/file2.h>
71 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table");
72 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader",
73 "file desc to leader structures");
74 MALLOC_DEFINE(M_FILE, "file", "Open file structure");
75 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures");
77 static d_open_t fdopen;
81 static struct cdevsw fildesc_cdevsw = {
95 /* strategy */ nostrategy,
100 static int badfo_readwrite (struct file *fp, struct uio *uio,
101 struct ucred *cred, int flags, struct thread *td);
102 static int badfo_ioctl (struct file *fp, u_long com, caddr_t data,
104 static int badfo_poll (struct file *fp, int events,
105 struct ucred *cred, struct thread *td);
106 static int badfo_kqfilter (struct file *fp, struct knote *kn);
107 static int badfo_stat (struct file *fp, struct stat *sb, struct thread *td);
108 static int badfo_close (struct file *fp, struct thread *td);
111 * Descriptor management.
113 struct filelist filehead; /* head of list of open files */
114 int nfiles; /* actual number of open files */
118 * System calls on descriptors.
122 getdtablesize(struct getdtablesize_args *uap)
124 struct proc *p = curproc;
127 min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
132 * Duplicate a file descriptor to a particular value.
134 * note: keep in mind that a potential race condition exists when closing
135 * descriptors from a shared descriptor table (via rfork).
139 dup2(struct dup2_args *uap)
143 error = kern_dup(DUP_FIXED, uap->from, uap->to, uap->sysmsg_fds);
149 * Duplicate a file descriptor.
153 dup(struct dup_args *uap)
157 error = kern_dup(DUP_VARIABLE, uap->fd, 0, uap->sysmsg_fds);
163 kern_fcntl(int fd, int cmd, union fcntl_dat *dat)
165 struct thread *td = curthread;
166 struct proc *p = td->td_proc;
167 struct filedesc *fdp = p->p_fd;
172 int tmp, error, flg = F_POSIX;
176 if ((unsigned)fd >= fdp->fd_nfiles ||
177 (fp = fdp->fd_ofiles[fd]) == NULL)
179 pop = &fdp->fd_ofileflags[fd];
184 if (newmin >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
185 newmin > maxfilesperproc)
187 error = kern_dup(DUP_VARIABLE, fd, newmin, &dat->fc_fd);
191 dat->fc_cloexec = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0;
195 *pop = (*pop &~ UF_EXCLOSE) |
196 (dat->fc_cloexec & FD_CLOEXEC ? UF_EXCLOSE : 0);
200 dat->fc_flags = OFLAGS(fp->f_flag);
205 fp->f_flag &= ~FCNTLFLAGS;
206 fp->f_flag |= FFLAGS(dat->fc_flags & ~O_ACCMODE) & FCNTLFLAGS;
207 tmp = fp->f_flag & FNONBLOCK;
208 error = fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, td);
213 tmp = fp->f_flag & FASYNC;
214 error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, td);
219 fp->f_flag &= ~FNONBLOCK;
221 fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, td);
227 error = fo_ioctl(fp, FIOGETOWN, (caddr_t)&dat->fc_owner, td);
233 error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&dat->fc_owner, td);
239 /* Fall into F_SETLK */
242 if (fp->f_type != DTYPE_VNODE)
244 vp = (struct vnode *)fp->f_data;
247 * copyin/lockop may block
250 if (dat->fc_flock.l_whence == SEEK_CUR)
251 dat->fc_flock.l_start += fp->f_offset;
253 switch (dat->fc_flock.l_type) {
255 if ((fp->f_flag & FREAD) == 0) {
259 p->p_leader->p_flag |= P_ADVLOCK;
260 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
261 &dat->fc_flock, flg);
264 if ((fp->f_flag & FWRITE) == 0) {
268 p->p_leader->p_flag |= P_ADVLOCK;
269 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
270 &dat->fc_flock, flg);
273 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
274 &dat->fc_flock, F_POSIX);
280 /* Check for race with close */
281 if ((unsigned) fd >= fdp->fd_nfiles ||
282 fp != fdp->fd_ofiles[fd]) {
283 dat->fc_flock.l_whence = SEEK_SET;
284 dat->fc_flock.l_start = 0;
285 dat->fc_flock.l_len = 0;
286 dat->fc_flock.l_type = F_UNLCK;
287 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader,
288 F_UNLCK, &dat->fc_flock, F_POSIX);
294 if (fp->f_type != DTYPE_VNODE)
296 vp = (struct vnode *)fp->f_data;
298 * copyin/lockop may block
301 if (dat->fc_flock.l_type != F_RDLCK &&
302 dat->fc_flock.l_type != F_WRLCK &&
303 dat->fc_flock.l_type != F_UNLCK) {
307 if (dat->fc_flock.l_whence == SEEK_CUR)
308 dat->fc_flock.l_start += fp->f_offset;
309 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK,
310 &dat->fc_flock, F_POSIX);
320 * The file control system call.
323 fcntl(struct fcntl_args *uap)
330 dat.fc_fd = uap->arg;
333 dat.fc_cloexec = uap->arg;
336 dat.fc_flags = uap->arg;
339 dat.fc_owner = uap->arg;
344 error = copyin((caddr_t)uap->arg, &dat.fc_flock,
345 sizeof(struct flock));
351 error = kern_fcntl(uap->fd, uap->cmd, &dat);
356 uap->sysmsg_result = dat.fc_fd;
359 uap->sysmsg_result = dat.fc_cloexec;
362 uap->sysmsg_result = dat.fc_flags;
365 uap->sysmsg_result = dat.fc_owner;
367 error = copyout(&dat.fc_flock, (caddr_t)uap->arg,
368 sizeof(struct flock));
377 * Common code for dup, dup2, and fcntl(F_DUPFD).
379 * The type flag can be either DUP_FIXED or DUP_VARIABLE. DUP_FIXED tells
380 * kern_dup() to destructively dup over an existing file descriptor if new
381 * is already open. DUP_VARIABLE tells kern_dup() to find the lowest
382 * unused file descriptor that is greater than or equal to new.
385 kern_dup(enum dup_type type, int old, int new, int *res)
387 struct thread *td = curthread;
388 struct proc *p = td->td_proc;
389 struct filedesc *fdp = p->p_fd;
396 * Verify that we have a valid descriptor to dup from and
397 * possibly to dup to.
399 if (old < 0 || new < 0 || new > p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
400 new >= maxfilesperproc)
402 if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL)
404 if (type == DUP_FIXED && old == new) {
408 fp = fdp->fd_ofiles[old];
412 * Expand the table for the new descriptor if needed. This may
413 * block and drop and reacquire the fidedesc lock.
415 if (type == DUP_VARIABLE || new >= fdp->fd_nfiles) {
416 error = fdalloc(p, new, &newfd);
422 if (type == DUP_VARIABLE)
426 * If the old file changed out from under us then treat it as a
427 * bad file descriptor. Userland should do its own locking to
430 if (fdp->fd_ofiles[old] != fp) {
431 if (fdp->fd_ofiles[new] == NULL) {
432 if (new < fdp->fd_freefile)
433 fdp->fd_freefile = new;
434 while (fdp->fd_lastfile > 0 &&
435 fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
441 KASSERT(old != new, ("new fd is same as old"));
444 * Save info on the descriptor being overwritten. We have
445 * to do the unmap now, but we cannot close it without
446 * introducing an ownership race for the slot.
448 delfp = fdp->fd_ofiles[new];
449 if (delfp != NULL && p->p_fdtol != NULL) {
451 * Ask fdfree() to sleep to ensure that all relevant
452 * process leaders can be traversed in closef().
454 fdp->fd_holdleaderscount++;
458 KASSERT(delfp == NULL || type == DUP_FIXED,
459 ("dup() picked an open file"));
461 if (delfp && (fdp->fd_ofileflags[new] & UF_MAPPED))
462 (void) munmapfd(p, new);
466 * Duplicate the source descriptor, update lastfile
468 fdp->fd_ofiles[new] = fp;
469 fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE;
470 if (new > fdp->fd_lastfile)
471 fdp->fd_lastfile = new;
475 * If we dup'd over a valid file, we now own the reference to it
476 * and must dispose of it using closef() semantics (as if a
477 * close() were performed on it).
480 (void) closef(delfp, td);
482 fdp->fd_holdleaderscount--;
483 if (fdp->fd_holdleaderscount == 0 &&
484 fdp->fd_holdleaderswakeup != 0) {
485 fdp->fd_holdleaderswakeup = 0;
486 wakeup(&fdp->fd_holdleaderscount);
494 * If sigio is on the list associated with a process or process group,
495 * disable signalling from the device, remove sigio from the list and
499 funsetown(struct sigio *sigio)
506 *(sigio->sio_myref) = NULL;
508 if (sigio->sio_pgid < 0) {
509 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio,
511 } else /* if ((*sigiop)->sio_pgid > 0) */ {
512 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio,
515 crfree(sigio->sio_ucred);
516 free(sigio, M_SIGIO);
519 /* Free a list of sigio structures. */
521 funsetownlst(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(pid_t pgid, struct sigio **sigiop)
553 * Policy - Don't allow a process to FSETOWN a process
554 * in another session.
556 * Remove this test to allow maximum flexibility or
557 * restrict FSETOWN to the current process or process
558 * group for maximum safety.
560 if (proc->p_session != curproc->p_session)
564 } else /* if (pgid < 0) */ {
565 pgrp = pgfind(-pgid);
570 * Policy - Don't allow a process to FSETOWN a process
571 * in another session.
573 * Remove this test to allow maximum flexibility or
574 * restrict FSETOWN to the current process or process
575 * group for maximum safety.
577 if (pgrp->pg_session != curproc->p_session)
583 sigio = malloc(sizeof(struct sigio), M_SIGIO, M_WAITOK);
585 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio);
586 sigio->sio_proc = proc;
588 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
589 sigio->sio_pgrp = pgrp;
591 sigio->sio_pgid = pgid;
592 sigio->sio_ucred = crhold(curproc->p_ucred);
593 /* It would be convenient if p_ruid was in ucred. */
594 sigio->sio_ruid = curproc->p_ucred->cr_ruid;
595 sigio->sio_myref = sigiop;
603 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg).
606 fgetown(struct sigio *sigio)
608 return (sigio != NULL ? sigio->sio_pgid : 0);
612 * Close many file descriptors.
617 closefrom(struct closefrom_args *uap)
619 return(kern_closefrom(uap->fd));
623 kern_closefrom(int fd)
625 struct thread *td = curthread;
626 struct proc *p = td->td_proc;
627 struct filedesc *fdp;
632 if (fd < 0 || fd > fdp->fd_lastfile)
636 if (kern_close(fdp->fd_lastfile) == EINTR)
638 } while (fdp->fd_lastfile > fd);
644 * Close a file descriptor.
649 close(struct close_args *uap)
651 return(kern_close(uap->fd));
657 struct thread *td = curthread;
658 struct proc *p = td->td_proc;
659 struct filedesc *fdp;
667 if ((unsigned)fd >= fdp->fd_nfiles ||
668 (fp = fdp->fd_ofiles[fd]) == NULL)
671 if (fdp->fd_ofileflags[fd] & UF_MAPPED)
672 (void) munmapfd(p, fd);
674 fdp->fd_ofiles[fd] = NULL;
675 fdp->fd_ofileflags[fd] = 0;
677 if (p->p_fdtol != NULL) {
679 * Ask fdfree() to sleep to ensure that all relevant
680 * process leaders can be traversed in closef().
682 fdp->fd_holdleaderscount++;
687 * we now hold the fp reference that used to be owned by the descriptor
690 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
692 if (fd < fdp->fd_freefile)
693 fdp->fd_freefile = fd;
694 if (fd < fdp->fd_knlistsize)
695 knote_fdclose(p, fd);
696 error = closef(fp, td);
698 fdp->fd_holdleaderscount--;
699 if (fdp->fd_holdleaderscount == 0 &&
700 fdp->fd_holdleaderswakeup != 0) {
701 fdp->fd_holdleaderswakeup = 0;
702 wakeup(&fdp->fd_holdleaderscount);
709 kern_fstat(int fd, struct stat *ub)
711 struct thread *td = curthread;
712 struct proc *p = td->td_proc;
713 struct filedesc *fdp;
720 if ((unsigned)fd >= fdp->fd_nfiles ||
721 (fp = fdp->fd_ofiles[fd]) == NULL)
724 error = fo_stat(fp, ub, td);
731 * Return status information about a file descriptor.
734 fstat(struct fstat_args *uap)
739 error = kern_fstat(uap->fd, &st);
742 error = copyout(&st, uap->sb, sizeof(st));
747 * XXX: This is for source compatibility with NetBSD. Probably doesn't
751 nfstat(struct nfstat_args *uap)
757 error = kern_fstat(uap->fd, &st);
761 error = copyout(&nst, uap->sb, sizeof (nst));
767 * Return pathconf information about a file descriptor.
771 fpathconf(struct fpathconf_args *uap)
773 struct thread *td = curthread;
774 struct proc *p = td->td_proc;
775 struct filedesc *fdp;
782 if ((unsigned)uap->fd >= fdp->fd_nfiles ||
783 (fp = fdp->fd_ofiles[uap->fd]) == NULL)
788 switch (fp->f_type) {
791 if (uap->name != _PC_PIPE_BUF) {
794 uap->sysmsg_result = PIPE_BUF;
800 vp = (struct vnode *)fp->f_data;
801 error = VOP_PATHCONF(vp, uap->name, uap->sysmsg_fds);
812 * Allocate a file descriptor for the process.
815 SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, "");
818 fdalloc(struct proc *p, int want, int *result)
820 struct filedesc *fdp = p->p_fd;
822 int lim, last, nfiles;
823 struct file **newofile;
827 * Search for a free descriptor starting at the higher
828 * of want or fd_freefile. If that fails, consider
829 * expanding the ofile array.
831 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
833 last = min(fdp->fd_nfiles, lim);
834 if ((i = want) < fdp->fd_freefile)
835 i = fdp->fd_freefile;
836 for (; i < last; i++) {
837 if (fdp->fd_ofiles[i] == NULL) {
838 fdp->fd_ofileflags[i] = 0;
839 if (i > fdp->fd_lastfile)
840 fdp->fd_lastfile = i;
841 if (want <= fdp->fd_freefile)
842 fdp->fd_freefile = i;
849 * No space in current array. Expand?
851 if (fdp->fd_nfiles >= lim)
853 if (fdp->fd_nfiles < NDEXTENT)
856 nfiles = 2 * fdp->fd_nfiles;
857 newofile = malloc(nfiles * OFILESIZE, M_FILEDESC, M_WAITOK);
860 * deal with file-table extend race that might have occured
861 * when malloc was blocked.
863 if (fdp->fd_nfiles >= nfiles) {
864 free(newofile, M_FILEDESC);
867 newofileflags = (char *) &newofile[nfiles];
869 * Copy the existing ofile and ofileflags arrays
870 * and zero the new portion of each array.
872 bcopy(fdp->fd_ofiles, newofile,
873 (i = sizeof(struct file *) * fdp->fd_nfiles));
874 bzero((char *)newofile + i, nfiles * sizeof(struct file *) - i);
875 bcopy(fdp->fd_ofileflags, newofileflags,
876 (i = sizeof(char) * fdp->fd_nfiles));
877 bzero(newofileflags + i, nfiles * sizeof(char) - i);
878 if (fdp->fd_nfiles > NDFILE)
879 free(fdp->fd_ofiles, M_FILEDESC);
880 fdp->fd_ofiles = newofile;
881 fdp->fd_ofileflags = newofileflags;
882 fdp->fd_nfiles = nfiles;
889 * Check to see whether n user file descriptors
890 * are available to the process p.
893 fdavail(struct proc *p, int n)
895 struct filedesc *fdp = p->p_fd;
899 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
900 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0)
903 last = min(fdp->fd_nfiles, lim);
904 fpp = &fdp->fd_ofiles[fdp->fd_freefile];
905 for (i = last - fdp->fd_freefile; --i >= 0; fpp++) {
906 if (*fpp == NULL && --n <= 0)
914 * Create a new open file structure and allocate a file decriptor
915 * for the process that refers to it. If p is NULL, no descriptor
916 * is allocated and the file pointer is returned unassociated with
917 * any process. resultfd is only used if p is not NULL and may
918 * separately be NULL indicating that you don't need the returned fd.
920 * A held file pointer is returned. If a descriptor has been allocated
921 * an additional hold on the fp will be made due to the fd_ofiles[]
925 falloc(struct proc *p, struct file **resultfp, int *resultfd)
927 static struct timeval lastfail;
935 * Handle filetable full issues and root overfill.
937 if (nfiles >= maxfiles - maxfilesrootres &&
938 ((p && p->p_ucred->cr_ruid != 0) || nfiles >= maxfiles)) {
939 if (ppsratecheck(&lastfail, &curfail, 1)) {
940 printf("kern.maxfiles limit exceeded by uid %d, please see tuning(7).\n",
941 (p ? p->p_ucred->cr_ruid : -1));
948 * Allocate a new file descriptor.
951 fp = malloc(sizeof(struct file), M_FILE, M_WAITOK | M_ZERO);
953 fp->f_ops = &badfileops;
956 fp->f_cred = crhold(p->p_ucred);
958 fp->f_cred = crhold(proc0.p_ucred);
959 LIST_INSERT_HEAD(&filehead, fp, f_list);
961 if ((error = fsetfd(p, fp, resultfd)) != 0) {
962 fdrop(fp, p->p_thread);
974 * Associate a file pointer with a file descriptor. On success the fp
975 * will have an additional ref representing the fd_ofiles[] association.
978 fsetfd(struct proc *p, struct file *fp, int *resultfd)
986 if ((error = fdalloc(p, 0, &i)) == 0) {
988 p->p_fd->fd_ofiles[i] = fp;
995 fsetcred(struct file *fp, struct ucred *cr)
1003 * Free a file descriptor.
1006 ffree(struct file *fp)
1008 KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!"));
1009 LIST_REMOVE(fp, f_list);
1012 cache_drop(fp->f_ncp);
1020 * Build a new filedesc structure.
1023 fdinit(struct proc *p)
1025 struct filedesc0 *newfdp;
1026 struct filedesc *fdp = p->p_fd;
1028 newfdp = malloc(sizeof(struct filedesc0), M_FILEDESC, M_WAITOK|M_ZERO);
1030 newfdp->fd_fd.fd_cdir = fdp->fd_cdir;
1031 vref(newfdp->fd_fd.fd_cdir);
1032 newfdp->fd_fd.fd_ncdir = cache_hold(fdp->fd_ncdir);
1036 * rdir may not be set in e.g. proc0 or anything vm_fork'd off of
1037 * proc0, but should unconditionally exist in other processes.
1040 newfdp->fd_fd.fd_rdir = fdp->fd_rdir;
1041 vref(newfdp->fd_fd.fd_rdir);
1042 newfdp->fd_fd.fd_nrdir = cache_hold(fdp->fd_nrdir);
1045 newfdp->fd_fd.fd_jdir = fdp->fd_jdir;
1046 vref(newfdp->fd_fd.fd_jdir);
1047 newfdp->fd_fd.fd_njdir = cache_hold(fdp->fd_njdir);
1050 /* Create the file descriptor table. */
1051 newfdp->fd_fd.fd_refcnt = 1;
1052 newfdp->fd_fd.fd_cmask = cmask;
1053 newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles;
1054 newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags;
1055 newfdp->fd_fd.fd_nfiles = NDFILE;
1056 newfdp->fd_fd.fd_knlistsize = -1;
1058 return (&newfdp->fd_fd);
1062 * Share a filedesc structure.
1065 fdshare(struct proc *p)
1067 p->p_fd->fd_refcnt++;
1072 * Copy a filedesc structure.
1075 fdcopy(struct proc *p)
1077 struct filedesc *newfdp, *fdp = p->p_fd;
1081 /* Certain daemons might not have file descriptors. */
1085 newfdp = malloc(sizeof(struct filedesc0), M_FILEDESC, M_WAITOK);
1086 bcopy(fdp, newfdp, sizeof(struct filedesc));
1087 if (newfdp->fd_cdir) {
1088 vref(newfdp->fd_cdir);
1089 newfdp->fd_ncdir = cache_hold(newfdp->fd_ncdir);
1092 * We must check for fd_rdir here, at least for now because
1093 * the init process is created before we have access to the
1094 * rootvode to take a reference to it.
1096 if (newfdp->fd_rdir) {
1097 vref(newfdp->fd_rdir);
1098 newfdp->fd_nrdir = cache_hold(newfdp->fd_nrdir);
1100 if (newfdp->fd_jdir) {
1101 vref(newfdp->fd_jdir);
1102 newfdp->fd_njdir = cache_hold(newfdp->fd_njdir);
1104 newfdp->fd_refcnt = 1;
1107 * If the number of open files fits in the internal arrays
1108 * of the open file structure, use them, otherwise allocate
1109 * additional memory for the number of descriptors currently
1112 if (newfdp->fd_lastfile < NDFILE) {
1113 newfdp->fd_ofiles = ((struct filedesc0 *) newfdp)->fd_dfiles;
1114 newfdp->fd_ofileflags =
1115 ((struct filedesc0 *) newfdp)->fd_dfileflags;
1119 * Compute the smallest multiple of NDEXTENT needed
1120 * for the file descriptors currently in use,
1121 * allowing the table to shrink.
1123 i = newfdp->fd_nfiles;
1124 while (i > 2 * NDEXTENT && i > newfdp->fd_lastfile * 2)
1126 newfdp->fd_ofiles = malloc(i * OFILESIZE, M_FILEDESC, M_WAITOK);
1127 newfdp->fd_ofileflags = (char *) &newfdp->fd_ofiles[i];
1129 newfdp->fd_nfiles = i;
1130 bcopy(fdp->fd_ofiles, newfdp->fd_ofiles, i * sizeof(struct file **));
1131 bcopy(fdp->fd_ofileflags, newfdp->fd_ofileflags, i * sizeof(char));
1134 * kq descriptors cannot be copied.
1136 if (newfdp->fd_knlistsize != -1) {
1137 fpp = &newfdp->fd_ofiles[newfdp->fd_lastfile];
1138 for (i = newfdp->fd_lastfile; i >= 0; i--, fpp--) {
1139 if (*fpp != NULL && (*fpp)->f_type == DTYPE_KQUEUE) {
1141 if (i < newfdp->fd_freefile)
1142 newfdp->fd_freefile = i;
1144 if (*fpp == NULL && i == newfdp->fd_lastfile && i > 0)
1145 newfdp->fd_lastfile--;
1147 newfdp->fd_knlist = NULL;
1148 newfdp->fd_knlistsize = -1;
1149 newfdp->fd_knhash = NULL;
1150 newfdp->fd_knhashmask = 0;
1153 fpp = newfdp->fd_ofiles;
1154 for (i = newfdp->fd_lastfile; i-- >= 0; fpp++) {
1162 * Release a filedesc structure.
1165 fdfree(struct proc *p)
1167 struct thread *td = p->p_thread;
1168 struct filedesc *fdp = p->p_fd;
1171 struct filedesc_to_leader *fdtol;
1176 /* Certain daemons might not have file descriptors. */
1180 /* Check for special need to clear POSIX style locks */
1182 if (fdtol != NULL) {
1183 KASSERT(fdtol->fdl_refcount > 0,
1184 ("filedesc_to_refcount botch: fdl_refcount=%d",
1185 fdtol->fdl_refcount));
1186 if (fdtol->fdl_refcount == 1 &&
1187 (p->p_leader->p_flag & P_ADVLOCK) != 0) {
1189 fpp = fdp->fd_ofiles;
1190 for (i = 0, fpp = fdp->fd_ofiles;
1191 i <= fdp->fd_lastfile;
1194 (*fpp)->f_type != DTYPE_VNODE)
1198 lf.l_whence = SEEK_SET;
1201 lf.l_type = F_UNLCK;
1202 vp = (struct vnode *)fp->f_data;
1203 (void) VOP_ADVLOCK(vp,
1204 (caddr_t)p->p_leader,
1208 fdrop(fp, p->p_thread);
1209 fpp = fdp->fd_ofiles + i;
1213 if (fdtol->fdl_refcount == 1) {
1214 if (fdp->fd_holdleaderscount > 0 &&
1215 (p->p_leader->p_flag & P_ADVLOCK) != 0) {
1217 * close() or do_dup() has cleared a reference
1218 * in a shared file descriptor table.
1220 fdp->fd_holdleaderswakeup = 1;
1221 tsleep(&fdp->fd_holdleaderscount,
1225 if (fdtol->fdl_holdcount > 0) {
1227 * Ensure that fdtol->fdl_leader
1228 * remains valid in closef().
1230 fdtol->fdl_wakeup = 1;
1231 tsleep(fdtol, 0, "fdlhold", 0);
1235 fdtol->fdl_refcount--;
1236 if (fdtol->fdl_refcount == 0 &&
1237 fdtol->fdl_holdcount == 0) {
1238 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev;
1239 fdtol->fdl_prev->fdl_next = fdtol->fdl_next;
1244 free(fdtol, M_FILEDESC_TO_LEADER);
1246 if (--fdp->fd_refcnt > 0)
1249 * we are the last reference to the structure, we can
1250 * safely assume it will not change out from under us.
1252 fpp = fdp->fd_ofiles;
1253 for (i = fdp->fd_lastfile; i-- >= 0; fpp++) {
1255 (void) closef(*fpp, td);
1257 if (fdp->fd_nfiles > NDFILE)
1258 free(fdp->fd_ofiles, M_FILEDESC);
1260 cache_drop(fdp->fd_ncdir);
1261 vrele(fdp->fd_cdir);
1264 cache_drop(fdp->fd_nrdir);
1265 vrele(fdp->fd_rdir);
1268 cache_drop(fdp->fd_njdir);
1269 vrele(fdp->fd_jdir);
1272 free(fdp->fd_knlist, M_KQUEUE);
1274 free(fdp->fd_knhash, M_KQUEUE);
1275 free(fdp, M_FILEDESC);
1279 * For setugid programs, we don't want to people to use that setugidness
1280 * to generate error messages which write to a file which otherwise would
1281 * otherwise be off-limits to the process.
1283 * This is a gross hack to plug the hole. A better solution would involve
1284 * a special vop or other form of generalized access control mechanism. We
1285 * go ahead and just reject all procfs file systems accesses as dangerous.
1287 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is
1288 * sufficient. We also don't for check setugidness since we know we are.
1291 is_unsafe(struct file *fp)
1293 if (fp->f_type == DTYPE_VNODE &&
1294 ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS)
1300 * Make this setguid thing safe, if at all possible.
1303 setugidsafety(struct proc *p)
1305 struct thread *td = p->p_thread;
1306 struct filedesc *fdp = p->p_fd;
1309 /* Certain daemons might not have file descriptors. */
1314 * note: fdp->fd_ofiles may be reallocated out from under us while
1315 * we are blocked in a close. Be careful!
1317 for (i = 0; i <= fdp->fd_lastfile; i++) {
1320 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) {
1324 if ((fdp->fd_ofileflags[i] & UF_MAPPED) != 0)
1325 (void) munmapfd(p, i);
1327 if (i < fdp->fd_knlistsize)
1328 knote_fdclose(p, i);
1330 * NULL-out descriptor prior to close to avoid
1331 * a race while close blocks.
1333 fp = fdp->fd_ofiles[i];
1334 fdp->fd_ofiles[i] = NULL;
1335 fdp->fd_ofileflags[i] = 0;
1336 if (i < fdp->fd_freefile)
1337 fdp->fd_freefile = i;
1338 (void) closef(fp, td);
1341 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
1346 * Close any files on exec?
1349 fdcloseexec(struct proc *p)
1351 struct thread *td = p->p_thread;
1352 struct filedesc *fdp = p->p_fd;
1355 /* Certain daemons might not have file descriptors. */
1360 * We cannot cache fd_ofiles or fd_ofileflags since operations
1361 * may block and rip them out from under us.
1363 for (i = 0; i <= fdp->fd_lastfile; i++) {
1364 if (fdp->fd_ofiles[i] != NULL &&
1365 (fdp->fd_ofileflags[i] & UF_EXCLOSE)) {
1369 if (fdp->fd_ofileflags[i] & UF_MAPPED)
1370 (void) munmapfd(p, i);
1372 if (i < fdp->fd_knlistsize)
1373 knote_fdclose(p, i);
1375 * NULL-out descriptor prior to close to avoid
1376 * a race while close blocks.
1378 fp = fdp->fd_ofiles[i];
1379 fdp->fd_ofiles[i] = NULL;
1380 fdp->fd_ofileflags[i] = 0;
1381 if (i < fdp->fd_freefile)
1382 fdp->fd_freefile = i;
1383 (void) closef(fp, td);
1386 while (fdp->fd_lastfile > 0 && fdp->fd_ofiles[fdp->fd_lastfile] == NULL)
1391 * It is unsafe for set[ug]id processes to be started with file
1392 * descriptors 0..2 closed, as these descriptors are given implicit
1393 * significance in the Standard C library. fdcheckstd() will create a
1394 * descriptor referencing /dev/null for each of stdin, stdout, and
1395 * stderr that is not already open.
1398 fdcheckstd(struct proc *p)
1400 struct thread *td = p->p_thread;
1401 struct nlookupdata nd;
1402 struct filedesc *fdp;
1405 int fd, i, error, flags, devnull;
1412 for (i = 0; i < 3; i++) {
1413 if (fdp->fd_ofiles[i] != NULL)
1416 if ((error = falloc(p, &fp, NULL)) != 0)
1419 error = nlookup_init(&nd, "/dev/null", UIO_SYSSPACE,
1420 NLC_FOLLOW|NLC_LOCKVP);
1421 flags = FREAD | FWRITE;
1423 error = vn_open(&nd, fp, flags, 0);
1425 error = fsetfd(p, fp, &fd);
1433 error = kern_dup(DUP_FIXED, devnull, i, &retval);
1442 * Internal form of close.
1443 * Decrement reference count on file structure.
1444 * Note: td and/or p may be NULL when closing a file
1445 * that was being passed in a message.
1448 closef(struct file *fp, struct thread *td)
1452 struct filedesc_to_leader *fdtol;
1459 p = NULL; /* allow no proc association */
1461 p = td->td_proc; /* can also be NULL */
1464 * POSIX record locking dictates that any close releases ALL
1465 * locks owned by this process. This is handled by setting
1466 * a flag in the unlock to free ONLY locks obeying POSIX
1467 * semantics, and not to free BSD-style file locks.
1468 * If the descriptor was in a message, POSIX-style locks
1469 * aren't passed with the descriptor.
1472 fp->f_type == DTYPE_VNODE) {
1473 if ((p->p_leader->p_flag & P_ADVLOCK) != 0) {
1474 lf.l_whence = SEEK_SET;
1477 lf.l_type = F_UNLCK;
1478 vp = (struct vnode *)fp->f_data;
1479 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
1483 if (fdtol != NULL) {
1485 * Handle special case where file descriptor table
1486 * is shared between multiple process leaders.
1488 for (fdtol = fdtol->fdl_next;
1489 fdtol != p->p_fdtol;
1490 fdtol = fdtol->fdl_next) {
1491 if ((fdtol->fdl_leader->p_flag &
1494 fdtol->fdl_holdcount++;
1495 lf.l_whence = SEEK_SET;
1498 lf.l_type = F_UNLCK;
1499 vp = (struct vnode *)fp->f_data;
1500 (void) VOP_ADVLOCK(vp,
1501 (caddr_t)p->p_leader,
1502 F_UNLCK, &lf, F_POSIX);
1503 fdtol->fdl_holdcount--;
1504 if (fdtol->fdl_holdcount == 0 &&
1505 fdtol->fdl_wakeup != 0) {
1506 fdtol->fdl_wakeup = 0;
1512 return (fdrop(fp, td));
1516 fdrop(struct file *fp, struct thread *td)
1522 if (--fp->f_count > 0)
1524 if (fp->f_count < 0)
1525 panic("fdrop: count < 0");
1526 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) {
1527 lf.l_whence = SEEK_SET;
1530 lf.l_type = F_UNLCK;
1531 vp = (struct vnode *)fp->f_data;
1532 (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
1534 if (fp->f_ops != &badfileops)
1535 error = fo_close(fp, td);
1543 * Apply an advisory lock on a file descriptor.
1545 * Just attempt to get a record lock of the requested type on
1546 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0).
1550 flock(struct flock_args *uap)
1552 struct proc *p = curproc;
1553 struct filedesc *fdp = p->p_fd;
1558 if ((unsigned)uap->fd >= fdp->fd_nfiles ||
1559 (fp = fdp->fd_ofiles[uap->fd]) == NULL)
1561 if (fp->f_type != DTYPE_VNODE)
1562 return (EOPNOTSUPP);
1563 vp = (struct vnode *)fp->f_data;
1564 lf.l_whence = SEEK_SET;
1567 if (uap->how & LOCK_UN) {
1568 lf.l_type = F_UNLCK;
1569 fp->f_flag &= ~FHASLOCK;
1570 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK));
1572 if (uap->how & LOCK_EX)
1573 lf.l_type = F_WRLCK;
1574 else if (uap->how & LOCK_SH)
1575 lf.l_type = F_RDLCK;
1578 fp->f_flag |= FHASLOCK;
1579 if (uap->how & LOCK_NB)
1580 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK));
1581 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK|F_WAIT));
1585 * File Descriptor pseudo-device driver (/dev/fd/).
1587 * Opening minor device N dup()s the file (if any) connected to file
1588 * descriptor N belonging to the calling process. Note that this driver
1589 * consists of only the ``open()'' routine, because all subsequent
1590 * references to this file will be direct to the other driver.
1594 fdopen(dev_t dev, int mode, int type, struct thread *td)
1596 KKASSERT(td->td_proc != NULL);
1599 * XXX Kludge: set curproc->p_dupfd to contain the value of the
1600 * the file descriptor being sought for duplication. The error
1601 * return ensures that the vnode for this device will be released
1602 * by vn_open. Open will detect this special error and take the
1603 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
1604 * will simply report the error.
1606 td->td_proc->p_dupfd = minor(dev);
1611 * Duplicate the specified descriptor to a free descriptor.
1614 dupfdopen(struct filedesc *fdp, int indx, int dfd, int mode, int error)
1620 * If the to-be-dup'd fd number is greater than the allowed number
1621 * of file descriptors, or the fd to be dup'd has already been
1622 * closed, then reject.
1624 if ((u_int)dfd >= fdp->fd_nfiles ||
1625 (wfp = fdp->fd_ofiles[dfd]) == NULL) {
1630 * There are two cases of interest here.
1632 * For ENODEV simply dup (dfd) to file descriptor
1633 * (indx) and return.
1635 * For ENXIO steal away the file structure from (dfd) and
1636 * store it in (indx). (dfd) is effectively closed by
1639 * Any other error code is just returned.
1644 * Check that the mode the file is being opened for is a
1645 * subset of the mode of the existing descriptor.
1647 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag)
1649 fp = fdp->fd_ofiles[indx];
1651 if (fp && fdp->fd_ofileflags[indx] & UF_MAPPED)
1652 (void) munmapfd(p, indx);
1654 fdp->fd_ofiles[indx] = wfp;
1655 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
1657 if (indx > fdp->fd_lastfile)
1658 fdp->fd_lastfile = indx;
1660 * we now own the reference to fp that the ofiles[] array
1661 * used to own. Release it.
1664 fdrop(fp, curthread);
1669 * Steal away the file pointer from dfd, and stuff it into indx.
1671 fp = fdp->fd_ofiles[indx];
1673 if (fp && fdp->fd_ofileflags[indx] & UF_MAPPED)
1674 (void) munmapfd(p, indx);
1676 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd];
1677 fdp->fd_ofiles[dfd] = NULL;
1678 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
1679 fdp->fd_ofileflags[dfd] = 0;
1682 * we now own the reference to fp that the ofiles[] array
1683 * used to own. Release it.
1686 fdrop(fp, curthread);
1688 * Complete the clean up of the filedesc structure by
1689 * recomputing the various hints.
1691 if (indx > fdp->fd_lastfile) {
1692 fdp->fd_lastfile = indx;
1694 while (fdp->fd_lastfile > 0 &&
1695 fdp->fd_ofiles[fdp->fd_lastfile] == NULL) {
1698 if (dfd < fdp->fd_freefile)
1699 fdp->fd_freefile = dfd;
1710 struct filedesc_to_leader *
1711 filedesc_to_leader_alloc(struct filedesc_to_leader *old,
1712 struct proc *leader)
1714 struct filedesc_to_leader *fdtol;
1716 fdtol = malloc(sizeof(struct filedesc_to_leader),
1717 M_FILEDESC_TO_LEADER, M_WAITOK);
1718 fdtol->fdl_refcount = 1;
1719 fdtol->fdl_holdcount = 0;
1720 fdtol->fdl_wakeup = 0;
1721 fdtol->fdl_leader = leader;
1723 fdtol->fdl_next = old->fdl_next;
1724 fdtol->fdl_prev = old;
1725 old->fdl_next = fdtol;
1726 fdtol->fdl_next->fdl_prev = fdtol;
1728 fdtol->fdl_next = fdtol;
1729 fdtol->fdl_prev = fdtol;
1735 * Get file structures.
1738 sysctl_kern_file(SYSCTL_HANDLER_ARGS)
1740 struct kinfo_file kf;
1741 struct filedesc *fdp;
1749 * Note: because the number of file descriptors is calculated
1750 * in different ways for sizing vs returning the data,
1751 * there is information leakage from the first loop. However,
1752 * it is of a similar order of magnitude to the leakage from
1753 * global system statistics such as kern.openfiles.
1755 * When just doing a count, note that we cannot just count
1756 * the elements and add f_count via the filehead list because
1757 * threaded processes share their descriptor table and f_count might
1758 * still be '1' in that case.
1762 LIST_FOREACH(p, &allproc, p_list) {
1763 if (p->p_stat == SIDL)
1765 if (!PRISON_CHECK(req->td->td_proc->p_ucred, p->p_ucred) != 0)
1767 if ((fdp = p->p_fd) == NULL)
1769 for (n = 0; n < fdp->fd_nfiles; ++n) {
1770 if ((fp = fdp->fd_ofiles[n]) == NULL)
1772 if (req->oldptr == NULL) {
1775 kcore_make_file(&kf, fp, p->p_pid,
1776 p->p_ucred->cr_uid, n);
1777 error = SYSCTL_OUT(req, &kf, sizeof(kf));
1787 * When just calculating the size, overestimate a bit to try to
1788 * prevent system activity from causing the buffer-fill call
1791 if (req->oldptr == NULL) {
1792 count = (count + 16) + (count / 10);
1793 error = SYSCTL_OUT(req, NULL, count * sizeof(kf));
1798 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD,
1799 0, 0, sysctl_kern_file, "S,file", "Entire file table");
1801 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW,
1802 &maxfilesperproc, 0, "Maximum files allowed open per process");
1804 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW,
1805 &maxfiles, 0, "Maximum number of files");
1807 SYSCTL_INT(_kern, OID_AUTO, maxfilesrootres, CTLFLAG_RW,
1808 &maxfilesrootres, 0, "Descriptors reserved for root use");
1810 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD,
1811 &nfiles, 0, "System-wide number of open files");
1814 fildesc_drvinit(void *unused)
1818 cdevsw_add(&fildesc_cdevsw, 0, 0);
1819 for (fd = 0; fd < NUMFDESC; fd++) {
1820 make_dev(&fildesc_cdevsw, fd,
1821 UID_BIN, GID_BIN, 0666, "fd/%d", fd);
1823 make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "stdin");
1824 make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "stdout");
1825 make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "stderr");
1828 struct fileops badfileops = {
1852 badfo_ioctl(struct file *fp, u_long com, caddr_t data, struct thread *td)
1858 badfo_poll(struct file *fp, int events, struct ucred *cred, struct thread *td)
1864 badfo_kqfilter(struct file *fp, struct knote *kn)
1870 badfo_stat(struct file *fp, struct stat *sb, struct thread *td)
1876 badfo_close(struct file *fp, struct thread *td)
1881 SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,
1882 fildesc_drvinit,NULL)