ref: 5c1feb0ef0b795e5de71e956f9ccddcd5c4b7f21
dir: /sys/src/9/port/devsegment.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
enum
{
Qtopdir,
Qsegdir,
Qctl,
Qdata,
};
#define TYPE(x) (int)( (c)->qid.path & 0x7 )
#define SEG(x) ( ((c)->qid.path >> 3) & 0x3f )
#define PATH(s, t) ( ((s)<<3) | (t) )
typedef struct Globalseg Globalseg;
struct Globalseg
{
Ref;
char *name;
char *uid;
vlong length;
long perm;
Segio;
};
static Globalseg *globalseg[100];
static Lock globalseglock;
Segment* (*_globalsegattach)(char*);
static Segment* globalsegattach(char *name);
static Segment* fixedseg(uintptr va, ulong len);
/*
* returns with globalseg incref'd
*/
static Globalseg*
getgseg(Chan *c)
{
int x;
Globalseg *g;
x = SEG(c);
lock(&globalseglock);
if(x >= nelem(globalseg))
panic("getgseg");
g = globalseg[x];
if(g != nil)
incref(g);
unlock(&globalseglock);
if(g == nil)
error("global segment disappeared");
return g;
}
static void
putgseg(Globalseg *g)
{
if(g == nil || decref(g))
return;
if(g->s != nil)
putseg(g->s);
segio(g, nil, nil, 0, 0, 0);
free(g->name);
free(g->uid);
free(g);
}
static int
segmentgen(Chan *c, char*, Dirtab*, int, int s, Dir *dp)
{
Qid q;
Globalseg *g;
uintptr size;
switch(TYPE(c)) {
case Qtopdir:
if(s == DEVDOTDOT){
q.vers = 0;
q.path = PATH(0, Qtopdir);
q.type = QTDIR;
devdir(c, q, "#g", 0, eve, DMDIR|0777, dp);
break;
}
if(s >= nelem(globalseg))
return -1;
lock(&globalseglock);
g = globalseg[s];
if(g == nil){
unlock(&globalseglock);
return 0;
}
q.vers = 0;
q.path = PATH(s, Qsegdir);
q.type = QTDIR;
kstrcpy(up->genbuf, g->name, sizeof up->genbuf);
devdir(c, q, up->genbuf, 0, g->uid, DMDIR|0777, dp);
unlock(&globalseglock);
break;
case Qsegdir:
if(s == DEVDOTDOT){
q.vers = 0;
q.path = PATH(0, Qtopdir);
q.type = QTDIR;
devdir(c, q, "#g", 0, eve, DMDIR|0777, dp);
break;
}
/* fall through */
case Qctl:
case Qdata:
switch(s){
case 0:
g = getgseg(c);
q.vers = 0;
q.path = PATH(SEG(c), Qctl);
q.type = QTFILE;
devdir(c, q, "ctl", 0, g->uid, g->perm, dp);
putgseg(g);
break;
case 1:
g = getgseg(c);
q.vers = 0;
q.path = PATH(SEG(c), Qdata);
q.type = QTFILE;
if(g->s != nil)
size = g->s->top - g->s->base;
else
size = 0;
devdir(c, q, "data", size, g->uid, g->perm, dp);
putgseg(g);
break;
default:
return -1;
}
break;
}
return 1;
}
static void
segmentinit(void)
{
_globalsegattach = globalsegattach;
}
static Chan*
segmentattach(char *spec)
{
return devattach('g', spec);
}
static Walkqid*
segmentwalk(Chan *c, Chan *nc, char **name, int nname)
{
return devwalk(c, nc, name, nname, 0, 0, segmentgen);
}
static int
segmentstat(Chan *c, uchar *db, int n)
{
return devstat(c, db, n, 0, 0, segmentgen);
}
static Chan*
segmentopen(Chan *c, int omode)
{
Globalseg *g;
switch(TYPE(c)){
case Qtopdir:
case Qsegdir:
if(omode != 0)
error(Eisdir);
break;
case Qctl:
case Qdata:
g = getgseg(c);
if(waserror()){
putgseg(g);
nexterror();
}
devpermcheck(g->uid, g->perm, omode);
if(TYPE(c) == Qdata && g->s == nil)
error("segment not yet allocated");
c->aux = g;
poperror();
break;
default:
panic("segmentopen");
}
c->mode = openmode(omode);
c->offset = 0;
c->flag |= COPEN;
return c;
}
static void
segmentclose(Chan *c)
{
switch(TYPE(c)){
case Qctl:
case Qdata:
if(c->flag & COPEN){
putgseg(c->aux);
c->aux = nil;
}
}
}
static Chan*
segmentcreate(Chan *c, char *name, int omode, ulong perm)
{
int x, xfree;
Globalseg *g;
if(TYPE(c) != Qtopdir)
error(Eperm);
if(strlen(name) >= sizeof(up->genbuf))
error(Etoolong);
if(findphysseg(name) != nil)
error("name collision with physical segment");
if((perm & DMDIR) == 0)
error(Ebadarg);
if(waserror()){
unlock(&globalseglock);
nexterror();
}
lock(&globalseglock);
xfree = -1;
for(x = 0; x < nelem(globalseg); x++){
g = globalseg[x];
if(g == nil){
if(xfree < 0)
xfree = x;
} else if(strcmp(g->name, name) == 0)
error(Eexist);
}
if(xfree < 0)
error("too many global segments");
g = smalloc(sizeof(Globalseg));
g->ref = 1;
kstrdup(&g->name, name);
kstrdup(&g->uid, up->user);
g->perm = 0660;
globalseg[xfree] = g;
unlock(&globalseglock);
poperror();
c->qid.path = PATH(x, Qsegdir);
c->qid.type = QTDIR;
c->qid.vers = 0;
c->mode = openmode(omode);
return c;
}
static long
segmentread(Chan *c, void *a, long n, vlong voff)
{
Globalseg *g;
char buf[128];
if(c->qid.type == QTDIR)
return devdirread(c, a, n, (Dirtab *)0, 0L, segmentgen);
g = c->aux;
switch(TYPE(c)){
case Qctl:
if(g->s == nil)
error("segment not yet allocated");
if((g->s->type&SG_TYPE) == SG_FIXED)
snprint(buf, sizeof(buf), "va %#p %#p fixed %#p\n", g->s->base, g->s->top-g->s->base,
g->s->map[0]->pages[0]->pa);
else
snprint(buf, sizeof(buf), "va %#p %#p\n", g->s->base, g->s->top-g->s->base);
return readstr(voff, a, n, buf);
case Qdata:
return segio(g, g->s, a, n, voff, 1);
default:
panic("segmentread");
}
return 0; /* not reached */
}
static long
segmentwrite(Chan *c, void *a, long n, vlong voff)
{
Cmdbuf *cb;
Globalseg *g;
uintptr va, top, len;
if(c->qid.type == QTDIR)
error(Eperm);
g = c->aux;
switch(TYPE(c)){
case Qctl:
cb = parsecmd(a, n);
if(waserror()){
free(cb);
nexterror();
}
if(cb->nf > 0 && strcmp(cb->f[0], "va") == 0){
if(g->s != nil)
error("already has a virtual address");
if(cb->nf < 3)
error(Ebadarg);
va = strtoull(cb->f[1], 0, 0);
len = strtoull(cb->f[2], 0, 0);
top = PGROUND(va + len);
va = va&~(BY2PG-1);
if(va == 0 || top > USTKTOP || top <= va)
error(Ebadarg);
len = top - va;
if(len > SEGMAXSIZE)
error(Enovmem);
if(cb->nf >= 4 && strcmp(cb->f[3], "fixed") == 0){
if(!iseve())
error(Eperm);
g->s = fixedseg(va, len/BY2PG);
} else
g->s = newseg(SG_SHARED, va, len/BY2PG);
} else
error(Ebadctl);
free(cb);
poperror();
break;
case Qdata:
return segio(g, g->s, a, n, voff, 0);
default:
panic("segmentwrite");
}
return 0; /* not reached */
}
static int
segmentwstat(Chan *c, uchar *dp, int n)
{
Globalseg *g;
Dir *d;
if(c->qid.type == QTDIR)
error(Eperm);
d = nil;
g = getgseg(c);
if(waserror()){
free(d);
putgseg(g);
nexterror();
}
if(strcmp(g->uid, up->user) && !iseve())
error(Eperm);
d = smalloc(sizeof(Dir)+n);
n = convM2D(dp, n, &d[0], (char*)&d[1]);
if(n == 0)
error(Eshortstat);
if(!emptystr(d->uid))
kstrdup(&g->uid, d->uid);
if(d->mode != ~0UL)
g->perm = d->mode&0777;
free(d);
putgseg(g);
poperror();
return n;
}
static void
segmentremove(Chan *c)
{
Globalseg *g;
int x;
if(TYPE(c) != Qsegdir)
error(Eperm);
lock(&globalseglock);
x = SEG(c);
g = globalseg[x];
globalseg[x] = nil;
unlock(&globalseglock);
if(g != nil)
putgseg(g);
}
/*
* called by segattach()
*/
static Segment*
globalsegattach(char *name)
{
int x;
Globalseg *g;
Segment *s;
if(waserror()){
unlock(&globalseglock);
nexterror();
}
lock(&globalseglock);
for(x = 0; x < nelem(globalseg); x++){
g = globalseg[x];
if(g != nil && strcmp(g->name, name) == 0)
goto Found;
}
unlock(&globalseglock);
poperror();
return nil;
Found:
devpermcheck(g->uid, g->perm, ORDWR);
s = g->s;
if(s == nil)
error("global segment not assigned a virtual address");
incref(s);
unlock(&globalseglock);
poperror();
return s;
}
/*
* allocate a fixed segment with sequential run of of adjacent
* user memory pages.
*/
static Segment*
fixedseg(uintptr va, ulong len)
{
KMap *k;
Segment *s;
Page **f, *p, *l, *h;
ulong n, i;
int color;
s = newseg(SG_FIXED, va, len);
if(waserror()){
putseg(s);
nexterror();
}
lock(&palloc);
i = 0;
l = palloc.pages;
color = getpgcolor(va);
for(n = palloc.user; n >= len; n--, l++){
if(l->ref != 0 || i != 0 && (l[-1].pa+BY2PG) != l->pa || i == 0 && l->color != color){
Retry:
i = 0;
continue;
}
if(++i < len)
continue;
i = 0;
h = nil;
f = &palloc.head;
while((p = *f) != nil){
if(p > &l[-len] && p <= l){
*f = p->next;
p->next = h;
h = p;
if(++i < len)
continue;
break;
}
f = &p->next;
}
palloc.freecount -= i;
if(i != len){
while((p = h) != nil){
h = h->next;
pagechainhead(p);
}
goto Retry;
}
unlock(&palloc);
p = &l[-len];
do {
p++;
p->ref = 1;
p->va = va;
p->modref = 0;
p->txtflush = ~0;
k = kmap(p);
memset((void*)VA(k), 0, BY2PG);
kunmap(k);
segpage(s, p);
va += BY2PG;
} while(p != l);
poperror();
return s;
}
unlock(&palloc);
error(Enomem);
return nil;
}
Dev segmentdevtab = {
'g',
"segment",
devreset,
segmentinit,
devshutdown,
segmentattach,
segmentwalk,
segmentstat,
segmentopen,
segmentcreate,
segmentclose,
segmentread,
devbread,
segmentwrite,
devbwrite,
segmentremove,
segmentwstat,
};