ref: caef73363f896a1405ce6b9b6435f91e47a9b188
dir: /emu/Plan9/devsrv9.c/
#include "dat.h" #include "fns.h" #include "error.h" typedef struct Srv Srv; struct Srv { Ref; int fd; /* fd for opened /srv or /srv/X, or -1 */ int sfd; /* fd for created /srv entry or -1 */ uvlong path; Srv *next; }; static QLock srv9lk; static Srv *srv9; static Srv *srvroot; static char* srvname(Chan *c) { char *p; p = strrchr(c->name->s, '/'); if(p == nil) return ""; return p+1; } static Srv* srvget(uvlong path) { Srv *sv; qlock(&srv9lk); for(sv = srv9; sv != nil; sv = sv->next) if(sv->path == path){ incref(sv); qunlock(&srv9lk); return sv; } sv = smalloc(sizeof(*sv)); sv->path = path; sv->fd = -1; sv->sfd = -1; sv->ref = 1; sv->next = srv9; srv9 = sv; qunlock(&srv9lk); return sv; } static void srvput(Srv *sv) { Srv **l; int fd, sfd; if(sv != nil && decref(sv) == 0){ qlock(&srv9lk); for(l = &srv9; *l != nil; l = &(*l)->next) if(*l == sv){ *l = sv->next; break; } qunlock(&srv9lk); fd = sv->fd; sfd = sv->sfd; free(sv); if(sfd >= 0){ osenter(); close(sfd); osleave(); } if(fd >= 0){ osenter(); close(fd); osleave(); } } } static void srv9init(void) { Srv *sv; sv = mallocz(sizeof(*srvroot), 1); sv->path = 0; sv->fd = -1; sv->ref = 1; /* subsequently never reaches zero */ srvroot = srv9 = sv; } static Chan* srv9attach(char *spec) { Chan *c; if(*spec) error(Ebadspec); c = devattach(L'₪', spec); if(c != nil){ incref(srvroot); c->aux = srvroot; } return c; } static Walkqid* srv9walk(Chan *c, Chan *nc, char **name, int nname) { int j, alloc; Walkqid *wq; char *n; Dir *d; if(nname > 0) isdir(c); alloc = 0; wq = smalloc(sizeof(Walkqid)+(nname-1)*sizeof(Qid)); if(waserror()){ if(alloc) cclose(wq->clone); free(wq); return nil; } if(nc == nil){ nc = devclone(c); nc->type = 0; /* device doesn't know about this channel yet */ alloc = 1; } wq->clone = nc; for(j=0; j<nname; j++){ if(!(nc->qid.type&QTDIR)){ if(j==0) error(Enotdir); break; } n = name[j]; if(strcmp(n, ".") != 0 && strcmp(n, "..") != 0){ snprint(up->genbuf, sizeof(up->genbuf), "/srv/%s", n); d = dirstat(up->genbuf); if(d == nil){ if(j == 0) error(Enonexist); kstrcpy(up->env->errstr, Enonexist, ERRMAX); break; } nc->qid = d->qid; free(d); } wq->qid[wq->nqid++] = nc->qid; } poperror(); if(wq->nqid < nname){ if(alloc) cclose(wq->clone); wq->clone = nil; }else{ /* attach cloned channel to device */ wq->clone->type = c->type; if(wq->clone != c) nc->aux = srvget(nc->qid.path); } return wq; } static int srv9stat(Chan *c, uchar *db, int n) { Srv *sv; Dir d; if(c->qid.type & QTDIR){ devdir(c, c->qid, "#₪", 0, eve, 0775, &d); n = convD2M(&d, db, n); if(n == 0) error(Eshortstat); return n; } sv = c->aux; if(sv->fd >= 0){ osenter(); n = fstat(sv->fd, db, n); osleave(); }else{ osenter(); n = stat(srvname(c), db, n); osleave(); } return n; } static Chan* srv9open(Chan *c, int omode) { Srv *sv; char *args[10]; int fd[2], i, ifd, is9p; Dir *d; sv = c->aux; if(c->qid.type == QTDIR){ osenter(); sv->fd = open("/srv", omode); osleave(); if(sv->fd < 0) oserror(); c->mode = omode; c->flag |= COPEN; c->offset = 0; return c; } if(omode&OTRUNC || openmode(omode) != ORDWR) error(Eperm); if(sv->fd < 0){ snprint(up->genbuf, sizeof(up->genbuf), "/srv/%s", srvname(c)); /* check permission */ osenter(); ifd = open(up->genbuf, omode); osleave(); if(ifd < 0) oserror(); osenter(); d = dirfstat(ifd); is9p = d != nil && d->qid.type & QTMOUNT; free(d); osleave(); if(is9p){ close(ifd); /* spawn exportfs */ args[0] = "exportfs"; args[1] = "-S"; args[2] = up->genbuf; args[3] = nil; if(pipe(fd) < 0) oserror(); /* TO DO: without RFMEM there's a copy made of each page touched by any kproc until the exec */ switch(rfork(RFPROC|RFNOWAIT|RFREND|RFFDG|RFNAMEG|RFENVG)){ /* no sharing except NOTEG */ case -1: oserrstr(up->genbuf, sizeof(up->genbuf)); close(fd[0]); close(fd[1]); error(up->genbuf); case 0: for(i=3; i<MAXNFD; i++) if(i != fd[1]) close(i); dup(fd[1], 0); if(fd[0] != 0) close(fd[0]); dup(0, 1); exec("/bin/exportfs", args); exits("exportfs failed"); default: sv->fd = fd[0]; close(fd[1]); break; } }else sv->fd = ifd; } c->mode = ORDWR; c->offset = 0; c->flag |= COPEN; return c; } static void srv9close(Chan *c) { srvput(c->aux); } static long srv9read(Chan *c, void *va, long n, vlong off) { Srv *sv; sv = c->aux; osenter(); n = pread(sv->fd, va, n, off); osleave(); if(n < 0) oserror(); return n; } static long srv9write(Chan *c, void *va, long n, vlong off) { Srv *sv; sv = c->aux; osenter(); n = pwrite(sv->fd, va, n, off); osleave(); if(n == 0) error(Ehungup); if(n < 0) oserror(); return n; } static void srv9create(Chan *c, char *name, int omode, ulong perm) { Srv *sv; int sfd, fd[2]; vlong path; Dir *d; if(openmode(omode) != ORDWR) error(Eperm); if(pipe(fd) < 0) oserror(); if(waserror()){ close(fd[0]); close(fd[1]); nexterror(); } snprint(up->genbuf, sizeof(up->genbuf), "/srv/%s", name); osenter(); sfd = create(up->genbuf, OWRITE|ORCLOSE, perm); osleave(); if(sfd < 0) oserror(); if(waserror()){ close(sfd); nexterror(); } osenter(); if(fprint(sfd, "%d", fd[1]) < 0){ osleave(); oserror(); } d = dirfstat(sfd); osleave(); if(d != nil){ path = d->qid.path; free(d); }else oserror(); poperror(); poperror(); close(fd[1]); if(waserror()){ close(sfd); close(fd[0]); nexterror(); } sv = srvget(path); sv->fd = fd[0]; sv->sfd = sfd; poperror(); srvput((Srv*)c->aux); c->qid.type = QTFILE; c->qid.path = path; c->aux = sv; c->flag |= COPEN; c->mode = ORDWR; c->offset = 0; } Dev srv9devtab = { L'₪', "srv9", srv9init, srv9attach, srv9walk, srv9stat, srv9open, srv9create, /* TO DO */ srv9close, srv9read, devbread, srv9write, devbwrite, devremove, /* TO DO */ devwstat, /* TO DO */ };