ref: 0b9c6fa117c3fe571aed497579b3340b2f8a1164
dir: /sys/src/9/port/devdup.c/
#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h" /* Qid is (2*fd + (file is ctl))+1 */ static int dupgen(Chan *c, char *, Dirtab*, int, int s, Dir *dp) { Fgrp *fgrp = up->fgrp; Chan *f; static int perm[] = { 0400, 0200, 0600, 0 }; int p; Qid q; if(s == DEVDOTDOT){ devdir(c, c->qid, ".", 0, eve, 0555, dp); return 1; } if(s == 0) return 0; s--; if(s/2 > fgrp->maxfd) return -1; if((f=fgrp->fd[s/2]) == nil) return 0; if(s & 1){ p = 0400; sprint(up->genbuf, "%dctl", s/2); }else{ p = perm[f->mode&3]; sprint(up->genbuf, "%d", s/2); } mkqid(&q, s+1, 0, QTFILE); devdir(c, q, up->genbuf, 0, eve, p, dp); return 1; } static Chan* dupattach(char *spec) { return devattach('d', spec); } static Walkqid* dupwalk(Chan *c, Chan *nc, char **name, int nname) { return devwalk(c, nc, name, nname, (Dirtab *)0, 0, dupgen); } static int dupstat(Chan *c, uchar *db, int n) { return devstat(c, db, n, (Dirtab *)0, 0L, dupgen); } static Chan* dupopen(Chan *c, int omode) { Chan *f; int fd, twicefd; if(c->qid.type & QTDIR){ if(omode != 0) error(Eisdir); c->mode = 0; c->flag |= COPEN; c->offset = 0; return c; } if(c->qid.type & QTAUTH) error(Eperm); twicefd = c->qid.path - 1; fd = twicefd/2; if((twicefd & 1)){ /* ctl file */ f = c; f->mode = openmode(omode); f->flag |= COPEN; f->offset = 0; }else{ /* fd file */ f = fdtochan(fd, openmode(omode), 0, 1); cclose(c); } return f; } static void dupclose(Chan*) { } static long dupread(Chan *c, void *va, long n, vlong offset) { char *a = va; char buf[256]; int fd, twicefd; if(c->qid.type == QTDIR) return devdirread(c, a, n, (Dirtab *)0, 0L, dupgen); twicefd = c->qid.path - 1; fd = twicefd/2; if(twicefd & 1){ c = fdtochan(fd, -1, 0, 1); procfdprint(c, fd, buf, sizeof buf); cclose(c); return readstr((ulong)offset, va, n, buf); } panic("dupread"); return 0; } static long dupwrite(Chan*, void*, long, vlong) { error(Eperm); return 0; /* not reached */ } Dev dupdevtab = { 'd', "dup", devreset, devinit, devshutdown, dupattach, dupwalk, dupstat, dupopen, devcreate, dupclose, dupread, devbread, dupwrite, devbwrite, devremove, devwstat, };