use a two-level bitmap as suggested by mogul and banga for fdalloc;
approved thorpej@
This commit is contained in:
provos
parent
654720aaa9
commit
4b425670af
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@ -1,4 +1,4 @@
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/* $NetBSD: kern_descrip.c,v 1.114 2003/09/22 12:59:55 christos Exp $ */
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/* $NetBSD: kern_descrip.c,v 1.115 2003/10/30 07:27:02 provos Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1989, 1991, 1993
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@ -37,7 +37,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_descrip.c,v 1.114 2003/09/22 12:59:55 christos Exp $");
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__KERNEL_RCSID(0, "$NetBSD: kern_descrip.c,v 1.115 2003/10/30 07:27:02 provos Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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@ -82,7 +82,9 @@ MALLOC_DEFINE(M_IOCTLOPS, "ioctlops", "ioctl data buffer");
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static __inline void fd_used(struct filedesc *, int);
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static __inline void fd_unused(struct filedesc *, int);
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static __inline int find_next_zero(uint32_t *, int, u_int);
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int finishdup(struct proc *, int, int, register_t *);
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int find_last_set(struct filedesc *, int);
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int fcntl_forfs(int, struct proc *, int, void *);
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dev_type_open(filedescopen);
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@ -92,9 +94,70 @@ const struct cdevsw filedesc_cdevsw = {
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nostop, notty, nopoll, nommap, nokqfilter,
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};
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static __inline int
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find_next_zero(uint32_t *bitmap, int want, u_int bits)
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{
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int i, off, maxoff;
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uint32_t sub;
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if (want > bits)
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return -1;
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off = want >> NDENTRYSHIFT;
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i = want & NDENTRYMASK;
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if (i) {
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sub = bitmap[off] | ((u_int)~0 >> (NDENTRIES - i));
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if (sub != ~0)
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goto found;
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off++;
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}
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maxoff = NDLOSLOTS(bits);
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while (off < maxoff) {
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if ((sub = bitmap[off]) != ~0)
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goto found;
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off++;
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}
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return (-1);
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found:
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return (off << NDENTRYSHIFT) + ffs(~sub) - 1;
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}
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int
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find_last_set(struct filedesc *fd, int last)
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{
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int off, i;
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struct file **ofiles = fd->fd_ofiles;
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uint32_t *bitmap = fd->fd_lomap;
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off = (last - 1) >> NDENTRYSHIFT;
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while (!bitmap[off] && off >= 0)
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off--;
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if (off < 0)
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return (0);
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i = ((off + 1) << NDENTRYSHIFT) - 1;
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if (i >= last)
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i = last - 1;
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while (i > 0 && ofiles[i] == NULL)
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i--;
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return (i);
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}
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static __inline void
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fd_used(struct filedesc *fdp, int fd)
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{
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u_int off = fd >> NDENTRYSHIFT;
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fdp->fd_lomap[off] |= 1 << (fd & NDENTRYMASK);
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if (fdp->fd_lomap[off] == ~0)
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fdp->fd_himap[off >> NDENTRYSHIFT] |= 1 << (off & NDENTRYMASK);
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if (fd > fdp->fd_lastfile)
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fdp->fd_lastfile = fd;
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@ -103,19 +166,21 @@ fd_used(struct filedesc *fdp, int fd)
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static __inline void
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fd_unused(struct filedesc *fdp, int fd)
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{
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u_int off = fd >> NDENTRYSHIFT;
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if (fd < fdp->fd_freefile)
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fdp->fd_freefile = fd;
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if (fdp->fd_lomap[off] == ~0)
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fdp->fd_himap[off >> NDENTRYSHIFT] &= ~(1 << (off & NDENTRYMASK));
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fdp->fd_lomap[off] &= ~(1 << (fd & NDENTRYMASK));
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#ifdef DIAGNOSTIC
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if (fd > fdp->fd_lastfile)
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panic("fd_unused: fd_lastfile inconsistent");
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#endif
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if (fd == fdp->fd_lastfile) {
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do {
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fd--;
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} while (fd >= 0 && fdp->fd_ofiles[fd] == NULL);
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fdp->fd_lastfile = fd;
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}
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if (fd == fdp->fd_lastfile)
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fdp->fd_lastfile = find_last_set(fdp, fd);
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}
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/*
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@ -646,6 +711,7 @@ fdalloc(struct proc *p, int want, int *result)
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{
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struct filedesc *fdp;
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int i, lim, last;
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u_int off, new;
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fdp = p->p_fd;
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@ -656,15 +722,32 @@ fdalloc(struct proc *p, int want, int *result)
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*/
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lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles);
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last = min(fdp->fd_nfiles, lim);
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again:
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if ((i = want) < fdp->fd_freefile)
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i = fdp->fd_freefile;
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for (; i < last; i++) {
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if (fdp->fd_ofiles[i] == NULL) {
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fd_used(fdp, i);
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if (want <= fdp->fd_freefile)
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fdp->fd_freefile = i;
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*result = i;
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return (0);
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off = i >> NDENTRYSHIFT;
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new = find_next_zero(fdp->fd_himap, off,
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(last + NDENTRIES - 1) >> NDENTRYSHIFT);
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if (new != -1) {
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i = find_next_zero(&fdp->fd_lomap[new],
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new > off ? 0 : i & NDENTRYMASK, NDENTRIES);
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if (i == -1) {
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/*
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* free file descriptor in this block was
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* below want, try again with higher want.
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*/
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want = (new + 1) << NDENTRYSHIFT;
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goto again;
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}
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i += (new << NDENTRYSHIFT);
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if (i < last) {
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if (fdp->fd_ofiles[i] == NULL) {
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fd_used(fdp, i);
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if (want <= fdp->fd_freefile)
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fdp->fd_freefile = i;
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*result = i;
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return (0);
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}
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}
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}
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@ -683,6 +766,7 @@ fdexpand(struct proc *p)
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int i, nfiles;
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struct file **newofile;
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char *newofileflags;
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uint32_t *newhimap, *newlomap;
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fdp = p->p_fd;
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@ -705,6 +789,31 @@ fdexpand(struct proc *p)
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memset(newofileflags + i, 0, nfiles * sizeof(char) - i);
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if (fdp->fd_nfiles > NDFILE)
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free(fdp->fd_ofiles, M_FILEDESC);
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if (NDHISLOTS(nfiles) > NDHISLOTS(fdp->fd_nfiles)) {
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newhimap = malloc(NDHISLOTS(nfiles) * sizeof(uint32_t),
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M_FILEDESC, M_WAITOK);
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newlomap = malloc(NDLOSLOTS(nfiles) * sizeof(uint32_t),
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M_FILEDESC, M_WAITOK);
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memcpy(newhimap, fdp->fd_himap,
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(i = NDHISLOTS(fdp->fd_nfiles) * sizeof(uint32_t)));
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memset((char *)newhimap + i, 0,
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NDHISLOTS(nfiles) * sizeof(uint32_t) - i);
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memcpy(newlomap, fdp->fd_lomap,
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(i = NDLOSLOTS(fdp->fd_nfiles) * sizeof(uint32_t)));
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memset((char *)newlomap + i, 0,
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NDLOSLOTS(nfiles) * sizeof(uint32_t) - i);
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if (NDHISLOTS(fdp->fd_nfiles) > NDHISLOTS(NDFILE)) {
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free(fdp->fd_himap, M_FILEDESC);
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free(fdp->fd_lomap, M_FILEDESC);
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}
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fdp->fd_himap = newhimap;
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fdp->fd_lomap = newlomap;
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}
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fdp->fd_ofiles = newofile;
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fdp->fd_ofileflags = newofileflags;
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fdp->fd_nfiles = nfiles;
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@ -772,6 +881,7 @@ falloc(struct proc *p, struct file **resultfp, int *resultfd)
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if (nfiles >= maxfiles) {
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tablefull("file", "increase kern.maxfiles or MAXFILES");
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simple_unlock(&filelist_slock);
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fd_unused(p->p_fd, i);
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pool_put(&file_pool, fp);
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return (ENFILE);
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}
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@ -927,6 +1037,8 @@ fdinit1(struct filedesc0 *newfdp)
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newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags;
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newfdp->fd_fd.fd_nfiles = NDFILE;
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newfdp->fd_fd.fd_knlistsize = -1;
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newfdp->fd_fd.fd_himap = newfdp->fd_dhimap;
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newfdp->fd_fd.fd_lomap = newfdp->fd_dlomap;
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}
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/*
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@ -1008,9 +1120,23 @@ fdcopy(struct proc *p)
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newfdp->fd_ofiles = malloc(i * OFILESIZE, M_FILEDESC, M_WAITOK);
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newfdp->fd_ofileflags = (char *) &newfdp->fd_ofiles[i];
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}
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if (NDHISLOTS(i) <= NDHISLOTS(NDFILE)) {
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newfdp->fd_himap =
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((struct filedesc0 *) newfdp)->fd_dhimap;
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newfdp->fd_lomap =
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((struct filedesc0 *) newfdp)->fd_dlomap;
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} else {
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newfdp->fd_himap = malloc(NDHISLOTS(i) * sizeof(uint32_t),
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M_FILEDESC, M_WAITOK);
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newfdp->fd_lomap = malloc(NDLOSLOTS(i) * sizeof(uint32_t),
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M_FILEDESC, M_WAITOK);
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}
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newfdp->fd_nfiles = i;
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memcpy(newfdp->fd_ofiles, fdp->fd_ofiles, i * sizeof(struct file **));
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memcpy(newfdp->fd_ofileflags, fdp->fd_ofileflags, i * sizeof(char));
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memcpy(newfdp->fd_himap, fdp->fd_himap, NDHISLOTS(i)*sizeof(uint32_t));
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memcpy(newfdp->fd_lomap, fdp->fd_lomap, NDLOSLOTS(i)*sizeof(uint32_t));
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/*
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* kq descriptors cannot be copied.
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*/
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@ -1060,6 +1186,10 @@ fdfree(struct proc *p)
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p->p_fd = NULL;
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if (fdp->fd_nfiles > NDFILE)
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free(fdp->fd_ofiles, M_FILEDESC);
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if (NDHISLOTS(fdp->fd_nfiles) > NDHISLOTS(NDFILE)) {
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free(fdp->fd_himap, M_FILEDESC);
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free(fdp->fd_lomap, M_FILEDESC);
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}
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if (fdp->fd_knlist)
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free(fdp->fd_knlist, M_KEVENT);
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if (fdp->fd_knhash)
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@ -1,4 +1,4 @@
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/* $NetBSD: filedesc.h,v 1.30 2003/08/07 16:34:04 agc Exp $ */
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/* $NetBSD: filedesc.h,v 1.31 2003/10/30 07:27:02 provos Exp $ */
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/*
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* Copyright (c) 1990, 1993
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@ -50,11 +50,18 @@
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*/
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#define NDFILE 20
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#define NDEXTENT 50 /* 250 bytes in 256-byte alloc */
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#define NDENTRIES 32 /* 32 fds per entry */
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#define NDENTRYMASK (NDENTRIES - 1)
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#define NDENTRYSHIFT 5 /* bits per entry */
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#define NDLOSLOTS(x) (((x) + NDENTRIES - 1) >> NDENTRYSHIFT)
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#define NDHISLOTS(x) ((NDLOSLOTS(x) + NDENTRIES - 1) >> NDENTRYSHIFT)
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struct filedesc {
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struct file **fd_ofiles; /* file structures for open files */
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char *fd_ofileflags; /* per-process open file flags */
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int fd_nfiles; /* number of open files allocated */
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uint32_t *fd_himap; /* each bit points to 32 fds */
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uint32_t *fd_lomap; /* bitmap of free fds */
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int fd_lastfile; /* high-water mark of fd_ofiles */
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int fd_freefile; /* approx. next free file */
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int fd_refcnt; /* reference count */
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@ -91,6 +98,12 @@ struct filedesc0 {
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*/
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struct file *fd_dfiles[NDFILE];
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char fd_dfileflags[NDFILE];
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/*
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* These arrays are used when the number of open files is
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* <= 1024, and are then pointed to by the pointers above.
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*/
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uint32_t fd_dhimap[NDENTRIES >> NDENTRYSHIFT];
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uint32_t fd_dlomap[NDENTRIES];
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};
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/*
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