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4 * This code is derived from software contributed to The DragonFly Project
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71 * @(#)kern_descrip.c 8.6 (Berkeley) 4/19/94
72 * $FreeBSD: src/sys/kern/kern_descrip.c,v 1.81.2.19 2004/02/28 00:43:31 tegge Exp $
73 * $DragonFly: src/sys/kern/kern_descrip.c,v 1.56 2006/05/18 18:58:26 dillon Exp $
76 #include "opt_compat.h"
77 #include <sys/param.h>
78 #include <sys/systm.h>
79 #include <sys/malloc.h>
80 #include <sys/sysproto.h>
82 #include <sys/filedesc.h>
83 #include <sys/kernel.h>
84 #include <sys/sysctl.h>
85 #include <sys/vnode.h>
87 #include <sys/nlookup.h>
90 #include <sys/filio.h>
91 #include <sys/fcntl.h>
92 #include <sys/unistd.h>
93 #include <sys/resourcevar.h>
94 #include <sys/event.h>
95 #include <sys/kern_syscall.h>
96 #include <sys/kcore.h>
97 #include <sys/kinfo.h>
100 #include <vm/vm_extern.h>
102 #include <sys/thread2.h>
103 #include <sys/file2.h>
105 static MALLOC_DEFINE(M_FILEDESC, "file desc", "Open file descriptor table");
106 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "file desc to leader",
107 "file desc to leader structures");
108 MALLOC_DEFINE(M_FILE, "file", "Open file structure");
109 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures");
111 static d_open_t fdopen;
114 #define CDEV_MAJOR 22
115 static struct cdevsw fildesc_cdevsw = {
117 /* maj */ CDEV_MAJOR,
129 /* strategy */ nostrategy,
134 static int badfo_readwrite (struct file *fp, struct uio *uio,
135 struct ucred *cred, int flags);
136 static int badfo_ioctl (struct file *fp, u_long com, caddr_t data,
138 static int badfo_poll (struct file *fp, int events, struct ucred *cred);
139 static int badfo_kqfilter (struct file *fp, struct knote *kn);
140 static int badfo_stat (struct file *fp, struct stat *sb, struct ucred *cred);
141 static int badfo_close (struct file *fp);
142 static int badfo_shutdown (struct file *fp, int how);
145 * Descriptor management.
147 struct filelist filehead; /* head of list of open files */
148 int nfiles; /* actual number of open files */
152 * System calls on descriptors.
156 getdtablesize(struct getdtablesize_args *uap)
158 struct proc *p = curproc;
161 min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
166 * Duplicate a file descriptor to a particular value.
168 * note: keep in mind that a potential race condition exists when closing
169 * descriptors from a shared descriptor table (via rfork).
173 dup2(struct dup2_args *uap)
177 error = kern_dup(DUP_FIXED, uap->from, uap->to, uap->sysmsg_fds);
183 * Duplicate a file descriptor.
187 dup(struct dup_args *uap)
191 error = kern_dup(DUP_VARIABLE, uap->fd, 0, uap->sysmsg_fds);
197 kern_fcntl(int fd, int cmd, union fcntl_dat *dat, struct ucred *cred)
199 struct thread *td = curthread;
200 struct proc *p = td->td_proc;
201 struct filedesc *fdp = p->p_fd;
206 int tmp, error, flg = F_POSIX;
210 if ((unsigned)fd >= fdp->fd_nfiles ||
211 (fp = fdp->fd_files[fd].fp) == NULL)
213 pop = &fdp->fd_files[fd].fileflags;
218 if (newmin >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
219 newmin > maxfilesperproc)
221 error = kern_dup(DUP_VARIABLE, fd, newmin, &dat->fc_fd);
225 dat->fc_cloexec = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0;
229 *pop = (*pop &~ UF_EXCLOSE) |
230 (dat->fc_cloexec & FD_CLOEXEC ? UF_EXCLOSE : 0);
234 dat->fc_flags = OFLAGS(fp->f_flag);
239 fp->f_flag &= ~FCNTLFLAGS;
240 fp->f_flag |= FFLAGS(dat->fc_flags & ~O_ACCMODE) & FCNTLFLAGS;
241 tmp = fp->f_flag & FNONBLOCK;
242 error = fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, cred);
247 tmp = fp->f_flag & FASYNC;
248 error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, cred);
253 fp->f_flag &= ~FNONBLOCK;
255 fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, cred);
261 error = fo_ioctl(fp, FIOGETOWN, (caddr_t)&dat->fc_owner, cred);
267 error = fo_ioctl(fp, FIOSETOWN, (caddr_t)&dat->fc_owner, cred);
273 /* Fall into F_SETLK */
276 if (fp->f_type != DTYPE_VNODE)
278 vp = (struct vnode *)fp->f_data;
281 * copyin/lockop may block
284 if (dat->fc_flock.l_whence == SEEK_CUR)
285 dat->fc_flock.l_start += fp->f_offset;
287 switch (dat->fc_flock.l_type) {
289 if ((fp->f_flag & FREAD) == 0) {
293 p->p_leader->p_flag |= P_ADVLOCK;
294 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
295 &dat->fc_flock, flg);
298 if ((fp->f_flag & FWRITE) == 0) {
302 p->p_leader->p_flag |= P_ADVLOCK;
303 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
304 &dat->fc_flock, flg);
307 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
308 &dat->fc_flock, F_POSIX);
314 /* Check for race with close */
315 if ((unsigned) fd >= fdp->fd_nfiles ||
316 fp != fdp->fd_files[fd].fp) {
317 dat->fc_flock.l_whence = SEEK_SET;
318 dat->fc_flock.l_start = 0;
319 dat->fc_flock.l_len = 0;
320 dat->fc_flock.l_type = F_UNLCK;
321 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader,
322 F_UNLCK, &dat->fc_flock, F_POSIX);
328 if (fp->f_type != DTYPE_VNODE)
330 vp = (struct vnode *)fp->f_data;
332 * copyin/lockop may block
335 if (dat->fc_flock.l_type != F_RDLCK &&
336 dat->fc_flock.l_type != F_WRLCK &&
337 dat->fc_flock.l_type != F_UNLCK) {
341 if (dat->fc_flock.l_whence == SEEK_CUR)
342 dat->fc_flock.l_start += fp->f_offset;
343 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK,
344 &dat->fc_flock, F_POSIX);
354 * The file control system call.
357 fcntl(struct fcntl_args *uap)
364 dat.fc_fd = uap->arg;
367 dat.fc_cloexec = uap->arg;
370 dat.fc_flags = uap->arg;
373 dat.fc_owner = uap->arg;
378 error = copyin((caddr_t)uap->arg, &dat.fc_flock,
379 sizeof(struct flock));
385 error = kern_fcntl(uap->fd, uap->cmd, &dat, curproc->p_ucred);
390 uap->sysmsg_result = dat.fc_fd;
393 uap->sysmsg_result = dat.fc_cloexec;
396 uap->sysmsg_result = dat.fc_flags;
399 uap->sysmsg_result = dat.fc_owner;
401 error = copyout(&dat.fc_flock, (caddr_t)uap->arg,
402 sizeof(struct flock));
411 * Common code for dup, dup2, and fcntl(F_DUPFD).
413 * The type flag can be either DUP_FIXED or DUP_VARIABLE. DUP_FIXED tells
414 * kern_dup() to destructively dup over an existing file descriptor if new
415 * is already open. DUP_VARIABLE tells kern_dup() to find the lowest
416 * unused file descriptor that is greater than or equal to new.
419 kern_dup(enum dup_type type, int old, int new, int *res)
421 struct thread *td = curthread;
422 struct proc *p = td->td_proc;
423 struct filedesc *fdp = p->p_fd;
427 boolean_t fdalloced = FALSE;
431 * Verify that we have a valid descriptor to dup from and
432 * possibly to dup to.
434 if (old < 0 || new < 0 || new > p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
435 new >= maxfilesperproc)
437 if (old >= fdp->fd_nfiles || fdp->fd_files[old].fp == NULL)
439 if (type == DUP_FIXED && old == new) {
443 fp = fdp->fd_files[old].fp;
447 * Expand the table for the new descriptor if needed. This may
448 * block and drop and reacquire the fidedesc lock.
450 if (type == DUP_VARIABLE || new >= fdp->fd_nfiles) {
451 error = fdalloc(p, new, &newfd);
458 if (type == DUP_VARIABLE)
462 * If the old file changed out from under us then treat it as a
463 * bad file descriptor. Userland should do its own locking to
466 if (fdp->fd_files[old].fp != fp) {
467 if (fdp->fd_files[new].fp == NULL) {
469 fdreserve(fdp, newfd, -1);
470 if (new < fdp->fd_freefile)
471 fdp->fd_freefile = new;
472 while (fdp->fd_lastfile > 0 &&
473 fdp->fd_files[fdp->fd_lastfile].fp == NULL)
479 KASSERT(old != new, ("new fd is same as old"));
482 * Save info on the descriptor being overwritten. We have
483 * to do the unmap now, but we cannot close it without
484 * introducing an ownership race for the slot.
486 delfp = fdp->fd_files[new].fp;
487 if (delfp != NULL && p->p_fdtol != NULL) {
489 * Ask fdfree() to sleep to ensure that all relevant
490 * process leaders can be traversed in closef().
492 fdp->fd_holdleaderscount++;
496 KASSERT(delfp == NULL || type == DUP_FIXED,
497 ("dup() picked an open file"));
500 * Duplicate the source descriptor, update lastfile
502 if (new > fdp->fd_lastfile)
503 fdp->fd_lastfile = new;
504 if (!fdalloced && fdp->fd_files[new].fp == NULL)
505 fdreserve(fdp, new, 1);
506 fdp->fd_files[new].fp = fp;
507 fdp->fd_files[new].fileflags =
508 fdp->fd_files[old].fileflags & ~UF_EXCLOSE;
512 * If we dup'd over a valid file, we now own the reference to it
513 * and must dispose of it using closef() semantics (as if a
514 * close() were performed on it).
517 (void) closef(delfp, td);
519 fdp->fd_holdleaderscount--;
520 if (fdp->fd_holdleaderscount == 0 &&
521 fdp->fd_holdleaderswakeup != 0) {
522 fdp->fd_holdleaderswakeup = 0;
523 wakeup(&fdp->fd_holdleaderscount);
531 * If sigio is on the list associated with a process or process group,
532 * disable signalling from the device, remove sigio from the list and
536 funsetown(struct sigio *sigio)
541 *(sigio->sio_myref) = NULL;
543 if (sigio->sio_pgid < 0) {
544 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio,
546 } else /* if ((*sigiop)->sio_pgid > 0) */ {
547 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio,
550 crfree(sigio->sio_ucred);
551 free(sigio, M_SIGIO);
554 /* Free a list of sigio structures. */
556 funsetownlst(struct sigiolst *sigiolst)
560 while ((sigio = SLIST_FIRST(sigiolst)) != NULL)
565 * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg).
567 * After permission checking, add a sigio structure to the sigio list for
568 * the process or process group.
571 fsetown(pid_t pgid, struct sigio **sigiop)
587 * Policy - Don't allow a process to FSETOWN a process
588 * in another session.
590 * Remove this test to allow maximum flexibility or
591 * restrict FSETOWN to the current process or process
592 * group for maximum safety.
594 if (proc->p_session != curproc->p_session)
598 } else /* if (pgid < 0) */ {
599 pgrp = pgfind(-pgid);
604 * Policy - Don't allow a process to FSETOWN a process
605 * in another session.
607 * Remove this test to allow maximum flexibility or
608 * restrict FSETOWN to the current process or process
609 * group for maximum safety.
611 if (pgrp->pg_session != curproc->p_session)
617 sigio = malloc(sizeof(struct sigio), M_SIGIO, M_WAITOK);
619 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio);
620 sigio->sio_proc = proc;
622 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
623 sigio->sio_pgrp = pgrp;
625 sigio->sio_pgid = pgid;
626 sigio->sio_ucred = crhold(curproc->p_ucred);
627 /* It would be convenient if p_ruid was in ucred. */
628 sigio->sio_ruid = curproc->p_ucred->cr_ruid;
629 sigio->sio_myref = sigiop;
637 * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg).
640 fgetown(struct sigio *sigio)
642 return (sigio != NULL ? sigio->sio_pgid : 0);
646 * Close many file descriptors.
651 closefrom(struct closefrom_args *uap)
653 return(kern_closefrom(uap->fd));
657 kern_closefrom(int fd)
659 struct thread *td = curthread;
660 struct proc *p = td->td_proc;
661 struct filedesc *fdp;
666 if (fd < 0 || fd > fdp->fd_lastfile)
670 if (kern_close(fdp->fd_lastfile) == EINTR)
672 } while (fdp->fd_lastfile > fd);
678 * Close a file descriptor.
683 close(struct close_args *uap)
685 return(kern_close(uap->fd));
691 struct thread *td = curthread;
692 struct proc *p = td->td_proc;
693 struct filedesc *fdp;
701 if ((unsigned)fd >= fdp->fd_nfiles ||
702 (fp = fdp->fd_files[fd].fp) == NULL)
706 if (p->p_fdtol != NULL) {
708 * Ask fdfree() to sleep to ensure that all relevant
709 * process leaders can be traversed in closef().
711 fdp->fd_holdleaderscount++;
716 * we now hold the fp reference that used to be owned by the descriptor
719 while (fdp->fd_lastfile > 0 && fdp->fd_files[fdp->fd_lastfile].fp == NULL)
721 if (fd < fdp->fd_knlistsize)
722 knote_fdclose(p, fd);
723 error = closef(fp, td);
725 fdp->fd_holdleaderscount--;
726 if (fdp->fd_holdleaderscount == 0 &&
727 fdp->fd_holdleaderswakeup != 0) {
728 fdp->fd_holdleaderswakeup = 0;
729 wakeup(&fdp->fd_holdleaderscount);
736 * shutdown_args(int fd, int how)
739 kern_shutdown(int fd, int how)
741 struct thread *td = curthread;
742 struct proc *p = td->td_proc;
743 struct filedesc *fdp;
750 if ((unsigned)fd >= fdp->fd_nfiles ||
751 (fp = fdp->fd_files[fd].fp) == NULL)
754 error = fo_shutdown(fp, how);
761 shutdown(struct shutdown_args *uap)
765 error = kern_shutdown(uap->s, uap->how);
771 kern_fstat(int fd, struct stat *ub)
773 struct thread *td = curthread;
774 struct proc *p = td->td_proc;
775 struct filedesc *fdp;
782 if ((unsigned)fd >= fdp->fd_nfiles ||
783 (fp = fdp->fd_files[fd].fp) == NULL)
786 error = fo_stat(fp, ub, p->p_ucred);
793 * Return status information about a file descriptor.
796 fstat(struct fstat_args *uap)
801 error = kern_fstat(uap->fd, &st);
804 error = copyout(&st, uap->sb, sizeof(st));
809 * Return pathconf information about a file descriptor.
813 fpathconf(struct fpathconf_args *uap)
815 struct thread *td = curthread;
816 struct proc *p = td->td_proc;
817 struct filedesc *fdp;
824 if ((unsigned)uap->fd >= fdp->fd_nfiles ||
825 (fp = fdp->fd_files[uap->fd].fp) == NULL)
830 switch (fp->f_type) {
833 if (uap->name != _PC_PIPE_BUF) {
836 uap->sysmsg_result = PIPE_BUF;
842 vp = (struct vnode *)fp->f_data;
843 error = VOP_PATHCONF(vp, uap->name, uap->sysmsg_fds);
854 SYSCTL_INT(_debug, OID_AUTO, fdexpand, CTLFLAG_RD, &fdexpand, 0, "");
857 fdgrow(struct filedesc *fdp, int want)
859 struct fdnode *newfiles;
860 struct fdnode *oldfiles;
865 /* nf has to be of the form 2^n - 1 */
867 } while (nf <= want);
869 newfiles = malloc(nf * sizeof(struct fdnode), M_FILEDESC, M_WAITOK);
872 * deal with file-table extend race that might have occured
873 * when malloc was blocked.
875 if (fdp->fd_nfiles >= nf) {
876 free(newfiles, M_FILEDESC);
880 * Copy the existing ofile and ofileflags arrays
881 * and zero the new portion of each array.
883 extra = nf - fdp->fd_nfiles;
884 bcopy(fdp->fd_files, newfiles, fdp->fd_nfiles * sizeof(struct fdnode));
885 bzero(&newfiles[fdp->fd_nfiles], extra * sizeof(struct fdnode));
887 oldfiles = fdp->fd_files;
888 fdp->fd_files = newfiles;
891 if (oldfiles != fdp->fd_builtin_files)
892 free(oldfiles, M_FILEDESC);
897 * Number of nodes in right subtree, including the root.
900 right_subtree_size(int n)
902 return (n ^ (n | (n + 1)));
909 right_ancestor(int n)
911 return (n | (n + 1));
920 return ((n & (n + 1)) - 1);
924 fdreserve(struct filedesc *fdp, int fd, int incr)
927 fdp->fd_files[fd].allocated += incr;
928 KKASSERT(fdp->fd_files[fd].allocated >= 0);
929 fd = left_ancestor(fd);
934 * Allocate a file descriptor for the process.
937 fdalloc(struct proc *p, int want, int *result)
939 struct filedesc *fdp = p->p_fd;
940 int fd, rsize, rsum, node, lim;
942 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
945 if (want >= fdp->fd_nfiles)
949 * Search for a free descriptor starting at the higher
950 * of want or fd_freefile. If that fails, consider
951 * expanding the ofile array.
954 /* move up the tree looking for a subtree with a free node */
955 for (fd = max(want, fdp->fd_freefile); fd < min(fdp->fd_nfiles, lim);
956 fd = right_ancestor(fd)) {
957 if (fdp->fd_files[fd].allocated == 0)
960 rsize = right_subtree_size(fd);
961 if (fdp->fd_files[fd].allocated == rsize)
962 continue; /* right subtree full */
965 * Free fd is in the right subtree of the tree rooted at fd.
966 * Call that subtree R. Look for the smallest (leftmost)
967 * subtree of R with an unallocated fd: continue moving
968 * down the left branch until encountering a full left
969 * subtree, then move to the right.
971 for (rsum = 0, rsize /= 2; rsize > 0; rsize /= 2) {
973 rsum += fdp->fd_files[node].allocated;
974 if (fdp->fd_files[fd].allocated == rsum + rsize) {
975 fd = node; /* move to the right */
976 if (fdp->fd_files[node].allocated == 0)
985 * No space in current array. Expand?
987 if (fdp->fd_nfiles >= lim)
993 KKASSERT(fd < fdp->fd_nfiles);
994 fdp->fd_files[fd].fileflags = 0;
995 if (fd > fdp->fd_lastfile)
996 fdp->fd_lastfile = fd;
997 if (want <= fdp->fd_freefile)
998 fdp->fd_freefile = fd;
1000 KKASSERT(fdp->fd_files[fd].fp == NULL);
1001 fdreserve(fdp, fd, 1);
1006 * Check to see whether n user file descriptors
1007 * are available to the process p.
1010 fdavail(struct proc *p, int n)
1012 struct filedesc *fdp = p->p_fd;
1013 struct fdnode *fdnode;
1016 lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfilesperproc);
1017 if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0)
1020 last = min(fdp->fd_nfiles, lim);
1021 fdnode = &fdp->fd_files[fdp->fd_freefile];
1022 for (i = last - fdp->fd_freefile; --i >= 0; ++fdnode) {
1023 if (fdnode->fp == NULL && --n <= 0)
1031 * Create a new open file structure and allocate a file decriptor
1032 * for the process that refers to it. If p is NULL, no descriptor
1033 * is allocated and the file pointer is returned unassociated with
1034 * any process. resultfd is only used if p is not NULL and may
1035 * separately be NULL indicating that you don't need the returned fd.
1037 * A held file pointer is returned. If a descriptor has been allocated
1038 * an additional hold on the fp will be made due to the fd_files[]
1042 falloc(struct proc *p, struct file **resultfp, int *resultfd)
1044 static struct timeval lastfail;
1052 * Handle filetable full issues and root overfill.
1054 if (nfiles >= maxfiles - maxfilesrootres &&
1055 ((p && p->p_ucred->cr_ruid != 0) || nfiles >= maxfiles)) {
1056 if (ppsratecheck(&lastfail, &curfail, 1)) {
1057 printf("kern.maxfiles limit exceeded by uid %d, please see tuning(7).\n",
1058 (p ? p->p_ucred->cr_ruid : -1));
1065 * Allocate a new file descriptor.
1068 fp = malloc(sizeof(struct file), M_FILE, M_WAITOK | M_ZERO);
1070 fp->f_ops = &badfileops;
1073 fp->f_cred = crhold(p->p_ucred);
1075 fp->f_cred = crhold(proc0.p_ucred);
1076 LIST_INSERT_HEAD(&filehead, fp, f_list);
1078 if ((error = fsetfd(p, fp, resultfd)) != 0) {
1091 * Associate a file pointer with a file descriptor. On success the fp
1092 * will have an additional ref representing the fd_files[] association.
1095 fsetfd(struct proc *p, struct file *fp, int *resultfd)
1100 if ((error = fdalloc(p, 0, &fd)) == 0) {
1102 p->p_fd->fd_files[fd].fp = fp;
1109 funsetfd(struct filedesc *fdp, int fd)
1111 fdp->fd_files[fd].fp = NULL;
1112 fdp->fd_files[fd].fileflags = 0;
1113 fdreserve(fdp, fd, -1);
1114 if (fd < fdp->fd_freefile)
1115 fdp->fd_freefile = fd;
1119 fsetcred(struct file *fp, struct ucred *cr)
1127 * Free a file descriptor.
1130 ffree(struct file *fp)
1132 KASSERT((fp->f_count == 0), ("ffree: fp_fcount not 0!"));
1133 LIST_REMOVE(fp, f_list);
1136 cache_drop(fp->f_ncp);
1144 * Build a new filedesc structure.
1147 fdinit(struct proc *p)
1149 struct filedesc *newfdp;
1150 struct filedesc *fdp = p->p_fd;
1152 newfdp = malloc(sizeof(struct filedesc), M_FILEDESC, M_WAITOK|M_ZERO);
1154 newfdp->fd_cdir = fdp->fd_cdir;
1155 vref(newfdp->fd_cdir);
1156 newfdp->fd_ncdir = cache_hold(fdp->fd_ncdir);
1160 * rdir may not be set in e.g. proc0 or anything vm_fork'd off of
1161 * proc0, but should unconditionally exist in other processes.
1164 newfdp->fd_rdir = fdp->fd_rdir;
1165 vref(newfdp->fd_rdir);
1166 newfdp->fd_nrdir = cache_hold(fdp->fd_nrdir);
1169 newfdp->fd_jdir = fdp->fd_jdir;
1170 vref(newfdp->fd_jdir);
1171 newfdp->fd_njdir = cache_hold(fdp->fd_njdir);
1174 /* Create the file descriptor table. */
1175 newfdp->fd_refcnt = 1;
1176 newfdp->fd_cmask = cmask;
1177 newfdp->fd_files = newfdp->fd_builtin_files;
1178 newfdp->fd_nfiles = NDFILE;
1179 newfdp->fd_knlistsize = -1;
1185 * Share a filedesc structure.
1188 fdshare(struct proc *p)
1190 p->p_fd->fd_refcnt++;
1195 * Copy a filedesc structure.
1198 fdcopy(struct proc *p)
1200 struct filedesc *newfdp, *fdp = p->p_fd;
1201 struct fdnode *fdnode;
1204 /* Certain daemons might not have file descriptors. */
1208 newfdp = malloc(sizeof(struct filedesc), M_FILEDESC, M_WAITOK);
1210 if (newfdp->fd_cdir) {
1211 vref(newfdp->fd_cdir);
1212 newfdp->fd_ncdir = cache_hold(newfdp->fd_ncdir);
1215 * We must check for fd_rdir here, at least for now because
1216 * the init process is created before we have access to the
1217 * rootvode to take a reference to it.
1219 if (newfdp->fd_rdir) {
1220 vref(newfdp->fd_rdir);
1221 newfdp->fd_nrdir = cache_hold(newfdp->fd_nrdir);
1223 if (newfdp->fd_jdir) {
1224 vref(newfdp->fd_jdir);
1225 newfdp->fd_njdir = cache_hold(newfdp->fd_njdir);
1227 newfdp->fd_refcnt = 1;
1230 * If the number of open files fits in the internal arrays
1231 * of the open file structure, use them, otherwise allocate
1232 * additional memory for the number of descriptors currently
1235 if (newfdp->fd_lastfile < NDFILE) {
1236 newfdp->fd_files = newfdp->fd_builtin_files;
1240 * Compute the smallest file table size
1241 * for the file descriptors currently in use,
1242 * allowing the table to shrink.
1244 i = newfdp->fd_nfiles;
1245 while ((i-1)/2 > newfdp->fd_lastfile && (i-1)/2 > NDFILE)
1247 newfdp->fd_files = malloc(i * sizeof(struct fdnode),
1248 M_FILEDESC, M_WAITOK);
1250 newfdp->fd_nfiles = i;
1252 if (fdp->fd_files != fdp->fd_builtin_files ||
1253 newfdp->fd_files != newfdp->fd_builtin_files
1255 bcopy(fdp->fd_files, newfdp->fd_files,
1256 i * sizeof(struct fdnode));
1260 * kq descriptors cannot be copied.
1262 if (newfdp->fd_knlistsize != -1) {
1263 fdnode = &newfdp->fd_files[newfdp->fd_lastfile];
1264 for (i = newfdp->fd_lastfile; i >= 0; i--, fdnode--) {
1265 if (fdnode->fp != NULL && fdnode->fp->f_type == DTYPE_KQUEUE)
1266 funsetfd(newfdp, i); /* nulls out *fpp */
1267 if (fdnode->fp == NULL && i == newfdp->fd_lastfile && i > 0)
1268 newfdp->fd_lastfile--;
1270 newfdp->fd_knlist = NULL;
1271 newfdp->fd_knlistsize = -1;
1272 newfdp->fd_knhash = NULL;
1273 newfdp->fd_knhashmask = 0;
1276 fdnode = newfdp->fd_files;
1277 for (i = newfdp->fd_lastfile; i-- >= 0; fdnode++) {
1278 if (fdnode->fp != NULL)
1285 * Release a filedesc structure.
1288 fdfree(struct proc *p)
1290 struct thread *td = p->p_thread;
1291 struct filedesc *fdp = p->p_fd;
1292 struct fdnode *fdnode;
1294 struct filedesc_to_leader *fdtol;
1299 /* Certain daemons might not have file descriptors. */
1303 /* Check for special need to clear POSIX style locks */
1305 if (fdtol != NULL) {
1306 KASSERT(fdtol->fdl_refcount > 0,
1307 ("filedesc_to_refcount botch: fdl_refcount=%d",
1308 fdtol->fdl_refcount));
1309 if (fdtol->fdl_refcount == 1 &&
1310 (p->p_leader->p_flag & P_ADVLOCK) != 0) {
1312 fdnode = fdp->fd_files;
1313 for (i = 0; i <= fdp->fd_lastfile; i++, fdnode++) {
1314 if (fdnode->fp == NULL ||
1315 fdnode->fp->f_type != DTYPE_VNODE)
1319 lf.l_whence = SEEK_SET;
1322 lf.l_type = F_UNLCK;
1323 vp = (struct vnode *)fp->f_data;
1324 (void) VOP_ADVLOCK(vp,
1325 (caddr_t)p->p_leader,
1330 /* reload due to possible reallocation */
1331 fdnode = &fdp->fd_files[i];
1335 if (fdtol->fdl_refcount == 1) {
1336 if (fdp->fd_holdleaderscount > 0 &&
1337 (p->p_leader->p_flag & P_ADVLOCK) != 0) {
1339 * close() or do_dup() has cleared a reference
1340 * in a shared file descriptor table.
1342 fdp->fd_holdleaderswakeup = 1;
1343 tsleep(&fdp->fd_holdleaderscount,
1347 if (fdtol->fdl_holdcount > 0) {
1349 * Ensure that fdtol->fdl_leader
1350 * remains valid in closef().
1352 fdtol->fdl_wakeup = 1;
1353 tsleep(fdtol, 0, "fdlhold", 0);
1357 fdtol->fdl_refcount--;
1358 if (fdtol->fdl_refcount == 0 &&
1359 fdtol->fdl_holdcount == 0) {
1360 fdtol->fdl_next->fdl_prev = fdtol->fdl_prev;
1361 fdtol->fdl_prev->fdl_next = fdtol->fdl_next;
1366 free(fdtol, M_FILEDESC_TO_LEADER);
1368 if (--fdp->fd_refcnt > 0)
1371 * we are the last reference to the structure, we can
1372 * safely assume it will not change out from under us.
1374 for (i = 0; i <= fdp->fd_lastfile; ++i) {
1375 if (fdp->fd_files[i].fp)
1376 closef(fdp->fd_files[i].fp, td);
1378 if (fdp->fd_files != fdp->fd_builtin_files)
1379 free(fdp->fd_files, M_FILEDESC);
1381 cache_drop(fdp->fd_ncdir);
1382 vrele(fdp->fd_cdir);
1385 cache_drop(fdp->fd_nrdir);
1386 vrele(fdp->fd_rdir);
1389 cache_drop(fdp->fd_njdir);
1390 vrele(fdp->fd_jdir);
1393 free(fdp->fd_knlist, M_KQUEUE);
1395 free(fdp->fd_knhash, M_KQUEUE);
1396 free(fdp, M_FILEDESC);
1400 * For setugid programs, we don't want to people to use that setugidness
1401 * to generate error messages which write to a file which otherwise would
1402 * otherwise be off-limits to the process.
1404 * This is a gross hack to plug the hole. A better solution would involve
1405 * a special vop or other form of generalized access control mechanism. We
1406 * go ahead and just reject all procfs file systems accesses as dangerous.
1408 * Since setugidsafety calls this only for fd 0, 1 and 2, this check is
1409 * sufficient. We also don't for check setugidness since we know we are.
1412 is_unsafe(struct file *fp)
1414 if (fp->f_type == DTYPE_VNODE &&
1415 ((struct vnode *)(fp->f_data))->v_tag == VT_PROCFS)
1421 * Make this setguid thing safe, if at all possible.
1424 setugidsafety(struct proc *p)
1426 struct thread *td = p->p_thread;
1427 struct filedesc *fdp = p->p_fd;
1430 /* Certain daemons might not have file descriptors. */
1435 * note: fdp->fd_files may be reallocated out from under us while
1436 * we are blocked in a close. Be careful!
1438 for (i = 0; i <= fdp->fd_lastfile; i++) {
1441 if (fdp->fd_files[i].fp && is_unsafe(fdp->fd_files[i].fp)) {
1444 if (i < fdp->fd_knlistsize)
1445 knote_fdclose(p, i);
1447 * NULL-out descriptor prior to close to avoid
1448 * a race while close blocks.
1450 fp = fdp->fd_files[i].fp;
1455 while (fdp->fd_lastfile > 0 && fdp->fd_files[fdp->fd_lastfile].fp == NULL)
1460 * Close any files on exec?
1463 fdcloseexec(struct proc *p)
1465 struct thread *td = p->p_thread;
1466 struct filedesc *fdp = p->p_fd;
1469 /* Certain daemons might not have file descriptors. */
1474 * We cannot cache fd_files since operations may block and rip
1475 * them out from under us.
1477 for (i = 0; i <= fdp->fd_lastfile; i++) {
1478 if (fdp->fd_files[i].fp != NULL &&
1479 (fdp->fd_files[i].fileflags & UF_EXCLOSE)) {
1482 if (i < fdp->fd_knlistsize)
1483 knote_fdclose(p, i);
1485 * NULL-out descriptor prior to close to avoid
1486 * a race while close blocks.
1488 fp = fdp->fd_files[i].fp;
1493 while (fdp->fd_lastfile > 0 && fdp->fd_files[fdp->fd_lastfile].fp == NULL)
1498 * It is unsafe for set[ug]id processes to be started with file
1499 * descriptors 0..2 closed, as these descriptors are given implicit
1500 * significance in the Standard C library. fdcheckstd() will create a
1501 * descriptor referencing /dev/null for each of stdin, stdout, and
1502 * stderr that is not already open.
1505 fdcheckstd(struct proc *p)
1507 struct nlookupdata nd;
1508 struct filedesc *fdp;
1511 int fd, i, error, flags, devnull;
1518 for (i = 0; i < 3; i++) {
1519 if (fdp->fd_files[i].fp != NULL)
1522 if ((error = falloc(p, &fp, NULL)) != 0)
1525 error = nlookup_init(&nd, "/dev/null", UIO_SYSSPACE,
1526 NLC_FOLLOW|NLC_LOCKVP);
1527 flags = FREAD | FWRITE;
1529 error = vn_open(&nd, fp, flags, 0);
1531 error = fsetfd(p, fp, &fd);
1539 error = kern_dup(DUP_FIXED, devnull, i, &retval);
1548 * Internal form of close.
1549 * Decrement reference count on file structure.
1550 * Note: td and/or p may be NULL when closing a file
1551 * that was being passed in a message.
1554 closef(struct file *fp, struct thread *td)
1558 struct filedesc_to_leader *fdtol;
1565 p = NULL; /* allow no proc association */
1567 p = td->td_proc; /* can also be NULL */
1570 * POSIX record locking dictates that any close releases ALL
1571 * locks owned by this process. This is handled by setting
1572 * a flag in the unlock to free ONLY locks obeying POSIX
1573 * semantics, and not to free BSD-style file locks.
1574 * If the descriptor was in a message, POSIX-style locks
1575 * aren't passed with the descriptor.
1578 fp->f_type == DTYPE_VNODE) {
1579 if ((p->p_leader->p_flag & P_ADVLOCK) != 0) {
1580 lf.l_whence = SEEK_SET;
1583 lf.l_type = F_UNLCK;
1584 vp = (struct vnode *)fp->f_data;
1585 (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
1589 if (fdtol != NULL) {
1591 * Handle special case where file descriptor table
1592 * is shared between multiple process leaders.
1594 for (fdtol = fdtol->fdl_next;
1595 fdtol != p->p_fdtol;
1596 fdtol = fdtol->fdl_next) {
1597 if ((fdtol->fdl_leader->p_flag &
1600 fdtol->fdl_holdcount++;
1601 lf.l_whence = SEEK_SET;
1604 lf.l_type = F_UNLCK;
1605 vp = (struct vnode *)fp->f_data;
1606 (void) VOP_ADVLOCK(vp,
1607 (caddr_t)fdtol->fdl_leader,
1608 F_UNLCK, &lf, F_POSIX);
1609 fdtol->fdl_holdcount--;
1610 if (fdtol->fdl_holdcount == 0 &&
1611 fdtol->fdl_wakeup != 0) {
1612 fdtol->fdl_wakeup = 0;
1622 fdrop(struct file *fp)
1628 if (--fp->f_count > 0)
1630 if (fp->f_count < 0)
1631 panic("fdrop: count < 0");
1632 if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) {
1633 lf.l_whence = SEEK_SET;
1636 lf.l_type = F_UNLCK;
1637 vp = (struct vnode *)fp->f_data;
1638 (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0);
1640 if (fp->f_ops != &badfileops)
1641 error = fo_close(fp);
1649 * Apply an advisory lock on a file descriptor.
1651 * Just attempt to get a record lock of the requested type on
1652 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0).
1656 flock(struct flock_args *uap)
1658 struct proc *p = curproc;
1659 struct filedesc *fdp = p->p_fd;
1664 if ((unsigned)uap->fd >= fdp->fd_nfiles ||
1665 (fp = fdp->fd_files[uap->fd].fp) == NULL)
1667 if (fp->f_type != DTYPE_VNODE)
1668 return (EOPNOTSUPP);
1669 vp = (struct vnode *)fp->f_data;
1670 lf.l_whence = SEEK_SET;
1673 if (uap->how & LOCK_UN) {
1674 lf.l_type = F_UNLCK;
1675 fp->f_flag &= ~FHASLOCK;
1676 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, 0));
1678 if (uap->how & LOCK_EX)
1679 lf.l_type = F_WRLCK;
1680 else if (uap->how & LOCK_SH)
1681 lf.l_type = F_RDLCK;
1684 fp->f_flag |= FHASLOCK;
1685 if (uap->how & LOCK_NB)
1686 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, 0));
1687 return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_WAIT));
1691 * File Descriptor pseudo-device driver (/dev/fd/).
1693 * Opening minor device N dup()s the file (if any) connected to file
1694 * descriptor N belonging to the calling process. Note that this driver
1695 * consists of only the ``open()'' routine, because all subsequent
1696 * references to this file will be direct to the other driver.
1700 fdopen(dev_t dev, int mode, int type, struct thread *td)
1702 KKASSERT(td->td_lwp != NULL);
1705 * XXX Kludge: set curlwp->lwp_dupfd to contain the value of the
1706 * the file descriptor being sought for duplication. The error
1707 * return ensures that the vnode for this device will be released
1708 * by vn_open. Open will detect this special error and take the
1709 * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
1710 * will simply report the error.
1712 td->td_lwp->lwp_dupfd = minor(dev);
1717 * Duplicate the specified descriptor to a free descriptor.
1720 dupfdopen(struct filedesc *fdp, int indx, int dfd, int mode, int error)
1726 * If the to-be-dup'd fd number is greater than the allowed number
1727 * of file descriptors, or the fd to be dup'd has already been
1728 * closed, then reject.
1730 if ((u_int)dfd >= fdp->fd_nfiles ||
1731 (wfp = fdp->fd_files[dfd].fp) == NULL) {
1736 * There are two cases of interest here.
1738 * For ENODEV simply dup (dfd) to file descriptor
1739 * (indx) and return.
1741 * For ENXIO steal away the file structure from (dfd) and
1742 * store it in (indx). (dfd) is effectively closed by
1745 * Any other error code is just returned.
1750 * Check that the mode the file is being opened for is a
1751 * subset of the mode of the existing descriptor.
1753 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag)
1755 fp = fdp->fd_files[indx].fp;
1756 fdp->fd_files[indx].fp = wfp;
1757 fdp->fd_files[indx].fileflags = fdp->fd_files[dfd].fileflags;
1759 if (indx > fdp->fd_lastfile)
1760 fdp->fd_lastfile = indx;
1762 * we now own the reference to fp that the ofiles[] array
1763 * used to own. Release it.
1771 * Steal away the file pointer from dfd, and stuff it into indx.
1773 fp = fdp->fd_files[indx].fp;
1774 fdp->fd_files[indx].fp = fdp->fd_files[dfd].fp;
1775 fdp->fd_files[indx].fileflags = fdp->fd_files[dfd].fileflags;
1779 * we now own the reference to fp that the files[] array
1780 * used to own. Release it.
1785 * Complete the clean up of the filedesc structure by
1786 * recomputing the various hints.
1788 if (indx > fdp->fd_lastfile) {
1789 fdp->fd_lastfile = indx;
1791 while (fdp->fd_lastfile > 0 &&
1792 fdp->fd_files[fdp->fd_lastfile].fp == NULL) {
1805 struct filedesc_to_leader *
1806 filedesc_to_leader_alloc(struct filedesc_to_leader *old,
1807 struct proc *leader)
1809 struct filedesc_to_leader *fdtol;
1811 fdtol = malloc(sizeof(struct filedesc_to_leader),
1812 M_FILEDESC_TO_LEADER, M_WAITOK);
1813 fdtol->fdl_refcount = 1;
1814 fdtol->fdl_holdcount = 0;
1815 fdtol->fdl_wakeup = 0;
1816 fdtol->fdl_leader = leader;
1818 fdtol->fdl_next = old->fdl_next;
1819 fdtol->fdl_prev = old;
1820 old->fdl_next = fdtol;
1821 fdtol->fdl_next->fdl_prev = fdtol;
1823 fdtol->fdl_next = fdtol;
1824 fdtol->fdl_prev = fdtol;
1830 * Get file structures.
1833 sysctl_kern_file(SYSCTL_HANDLER_ARGS)
1835 struct kinfo_file kf;
1836 struct filedesc *fdp;
1845 * Note: because the number of file descriptors is calculated
1846 * in different ways for sizing vs returning the data,
1847 * there is information leakage from the first loop. However,
1848 * it is of a similar order of magnitude to the leakage from
1849 * global system statistics such as kern.openfiles.
1851 * When just doing a count, note that we cannot just count
1852 * the elements and add f_count via the filehead list because
1853 * threaded processes share their descriptor table and f_count might
1854 * still be '1' in that case.
1856 * Since the SYSCTL op can block, we must hold the process to
1857 * prevent it being ripped out from under us either in the
1858 * file descriptor loop or in the greater LIST_FOREACH. The
1859 * process may be in varying states of disrepair. If the process
1860 * is in SZOMB we may have caught it just as it is being removed
1861 * from the allproc list, we must skip it in that case to maintain
1862 * an unbroken chain through the allproc list.
1866 LIST_FOREACH(p, &allproc, p_list) {
1867 if (p->p_stat == SIDL || (p->p_flag & P_ZOMBIE))
1869 if (!PRISON_CHECK(req->td->td_proc->p_ucred, p->p_ucred) != 0)
1871 if ((fdp = p->p_fd) == NULL)
1874 for (n = 0; n < fdp->fd_nfiles; ++n) {
1875 if ((fp = fdp->fd_files[n].fp) == NULL)
1877 if (req->oldptr == NULL) {
1880 uid = p->p_ucred ? p->p_ucred->cr_uid : -1;
1881 kcore_make_file(&kf, fp, p->p_pid, uid, n);
1882 error = SYSCTL_OUT(req, &kf, sizeof(kf));
1893 * When just calculating the size, overestimate a bit to try to
1894 * prevent system activity from causing the buffer-fill call
1897 if (req->oldptr == NULL) {
1898 count = (count + 16) + (count / 10);
1899 error = SYSCTL_OUT(req, NULL, count * sizeof(kf));
1904 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD,
1905 0, 0, sysctl_kern_file, "S,file", "Entire file table");
1907 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW,
1908 &maxfilesperproc, 0, "Maximum files allowed open per process");
1910 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW,
1911 &maxfiles, 0, "Maximum number of files");
1913 SYSCTL_INT(_kern, OID_AUTO, maxfilesrootres, CTLFLAG_RW,
1914 &maxfilesrootres, 0, "Descriptors reserved for root use");
1916 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD,
1917 &nfiles, 0, "System-wide number of open files");
1920 fildesc_drvinit(void *unused)
1924 cdevsw_add(&fildesc_cdevsw, 0, 0);
1925 for (fd = 0; fd < NUMFDESC; fd++) {
1926 make_dev(&fildesc_cdevsw, fd,
1927 UID_BIN, GID_BIN, 0666, "fd/%d", fd);
1929 make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "stdin");
1930 make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "stdout");
1931 make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "stderr");
1934 struct fileops badfileops = {
1958 badfo_ioctl(struct file *fp, u_long com, caddr_t data, struct ucred *cred)
1964 badfo_poll(struct file *fp, int events, struct ucred *cred)
1970 badfo_kqfilter(struct file *fp, struct knote *kn)
1976 badfo_stat(struct file *fp, struct stat *sb, struct ucred *cred)
1982 badfo_close(struct file *fp)
1988 badfo_shutdown(struct file *fp, int how)
1994 nofo_shutdown(struct file *fp, int how)
1996 return (EOPNOTSUPP);
1999 SYSINIT(fildescdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,
2000 fildesc_drvinit,NULL)