0b33b3b8ad
The OCEXEC flag used to be maintained per channel, making it shared between all the file desciptors. This has a unexpected side effects with regard to channel passing drivers such as devdup (/fd), devsrv (/srv) and devshr (/shr). For example, opening a /srv file with OCEXEC makes it impossible to be remounted by exportfs as it internally does a exec() to mount and re-export it. There is no way to reset the flag. This change makes the OCEXEC flag per file descriptor, so a open with the OCEXEC flag only affects the fd group of the calling process, and not the channel itself. On rfork(RFFDG), the per file descriptor flags get copied. On dup(), the per file descriptor flags are reset. The second modification is that /fd, /srv and /shr should reject the ORCLOSE flag, as the files that are returned have already been opend.
147 lines
2.3 KiB
C
147 lines
2.3 KiB
C
#include "u.h"
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#include "../port/lib.h"
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#include "mem.h"
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#include "dat.h"
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#include "fns.h"
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#include "../port/error.h"
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/* Qid is (2*fd + (file is ctl))+1 */
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static int
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dupgen(Chan *c, char *, Dirtab*, int, int s, Dir *dp)
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{
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Fgrp *fgrp = up->fgrp;
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Chan *f;
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static int perm[] = { 0400, 0200, 0600, 0 };
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int p;
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Qid q;
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if(s == DEVDOTDOT){
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devdir(c, c->qid, ".", 0, eve, 0555, dp);
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return 1;
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}
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if(s == 0)
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return 0;
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s--;
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if(s/2 > fgrp->maxfd)
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return -1;
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if((f=fgrp->fd[s/2]) == nil)
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return 0;
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if(s & 1){
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p = 0400;
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sprint(up->genbuf, "%dctl", s/2);
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}else{
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p = perm[f->mode&3];
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sprint(up->genbuf, "%d", s/2);
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}
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mkqid(&q, s+1, 0, QTFILE);
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devdir(c, q, up->genbuf, 0, eve, p, dp);
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return 1;
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}
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static Chan*
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dupattach(char *spec)
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{
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return devattach('d', spec);
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}
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static Walkqid*
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dupwalk(Chan *c, Chan *nc, char **name, int nname)
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{
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return devwalk(c, nc, name, nname, (Dirtab *)0, 0, dupgen);
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}
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static int
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dupstat(Chan *c, uchar *db, int n)
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{
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return devstat(c, db, n, (Dirtab *)0, 0L, dupgen);
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}
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static Chan*
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dupopen(Chan *c, int omode)
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{
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Chan *f;
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int fd, twicefd;
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if(omode & ORCLOSE)
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error(Eperm);
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if(c->qid.type & QTDIR){
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if(omode != 0)
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error(Eisdir);
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c->mode = 0;
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c->flag |= COPEN;
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c->offset = 0;
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return c;
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}
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if(c->qid.type & QTAUTH)
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error(Eperm);
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twicefd = c->qid.path - 1;
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fd = twicefd/2;
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if((twicefd & 1)){
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/* ctl file */
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f = c;
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f->mode = openmode(omode);
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f->flag |= COPEN;
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f->offset = 0;
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}else{
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/* fd file */
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f = fdtochan(fd, openmode(omode), 0, 1);
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cclose(c);
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}
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return f;
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}
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static void
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dupclose(Chan*)
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{
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}
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static long
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dupread(Chan *c, void *va, long n, vlong offset)
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{
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char *a = va;
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char buf[256];
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int fd, twicefd;
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if(c->qid.type == QTDIR)
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return devdirread(c, a, n, (Dirtab *)0, 0L, dupgen);
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twicefd = c->qid.path - 1;
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fd = twicefd/2;
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if(twicefd & 1){
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c = fdtochan(fd, -1, 0, 1);
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procfdprint(c, fd, buf, sizeof buf);
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cclose(c);
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return readstr((ulong)offset, va, n, buf);
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}
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panic("dupread");
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return 0;
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}
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static long
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dupwrite(Chan*, void*, long, vlong)
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{
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error(Eperm);
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return 0; /* not reached */
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}
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Dev dupdevtab = {
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'd',
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"dup",
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devreset,
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devinit,
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devshutdown,
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dupattach,
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dupwalk,
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dupstat,
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dupopen,
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devcreate,
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dupclose,
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dupread,
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devbread,
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dupwrite,
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devbwrite,
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devremove,
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devwstat,
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};
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