20060303

1 files changed, 338 insertions, 0 deletions

diff --git a/os/port/devenv.c b/os/port/devenv.c
new file mode 100644
index 00000000..da6373a2
--- /dev/null
+++ b/os/port/devenv.c
@@ -0,0 +1,338 @@
+/*
+ *	devenv - environment
+ */
+#include "u.h"
+#include "../port/lib.h"
+#include "../port/error.h"
+#include "mem.h"
+#include	"dat.h"
+#include	"fns.h"
+
+static void envremove(Chan*);
+
+enum
+{
+	Maxenvsize = 16300,
+};
+
+static int
+envgen(Chan *c, char*, Dirtab*, int, int s, Dir *dp)
+{
+	Egrp *eg;
+	Evalue *e;
+
+	if(s == DEVDOTDOT){
+		devdir(c, c->qid, "#e", 0, eve, DMDIR|0775, dp);
+		return 1;
+	}
+	eg = up->env->egrp;
+	qlock(eg);
+	for(e = eg->entries; e != nil && s != 0; e = e->next)
+		s--;
+	if(e == nil) {
+		qunlock(eg);
+		return -1;
+	}
+	/* make sure name string continues to exist after we release lock */
+	kstrcpy(up->genbuf, e->var, sizeof up->genbuf);
+	devdir(c, e->qid, up->genbuf, e->len, eve, 0666, dp);
+	qunlock(eg);
+	return 1;
+}
+
+static Chan*
+envattach(char *spec)
+{
+	if(up->env == nil || up->env->egrp == nil)
+		error(Enodev);
+	return devattach('e', spec);
+}
+
+static Walkqid*
+envwalk(Chan *c, Chan *nc, char **name, int nname)
+{
+	return devwalk(c, nc, name, nname, 0, 0, envgen);
+}
+
+static int
+envstat(Chan *c, uchar *db, int n)
+{
+	if(c->qid.type & QTDIR)
+		c->qid.vers = up->env->egrp->vers;
+	return devstat(c, db, n, 0, 0, envgen);
+}
+
+static Chan *
+envopen(Chan *c, int mode)
+{
+	Egrp *eg;
+	Evalue *e;
+	
+	if(c->qid.type & QTDIR) {
+		if(mode != OREAD)
+			error(Eperm);
+		c->mode = mode;
+		c->flag |= COPEN;
+		c->offset = 0;
+		return c;
+	}
+	eg = up->env->egrp;
+	qlock(eg);
+	for(e = eg->entries; e != nil; e = e->next)
+		if(e->qid.path == c->qid.path)
+			break;
+	if(e == nil) {
+		qunlock(eg);
+		error(Enonexist);
+	}
+	if((mode & OTRUNC) && e->val) {
+		free(e->val);
+		e->val = 0;
+		e->len = 0;
+		e->qid.vers++;
+	}
+	qunlock(eg);
+	c->mode = openmode(mode);
+	c->flag |= COPEN;
+	c->offset = 0;
+	return c;
+}
+
+static void
+envcreate(Chan *c, char *name, int mode, ulong)
+{
+	Egrp *eg;
+	Evalue *e, **le;
+
+	if(c->qid.type != QTDIR)
+		error(Eperm);
+	if(strlen(name) >= sizeof(up->genbuf))
+		error("name too long");	/* needs to fit for stat */
+	mode = openmode(mode);
+	eg = up->env->egrp;
+	qlock(eg);
+	if(waserror()){
+		qunlock(eg);
+		nexterror();
+	}
+	for(le = &eg->entries; (e = *le) != nil; le = &e->next)
+		if(strcmp(e->var, name) == 0)
+			error(Eexist);
+	e = smalloc(sizeof(Evalue));
+	e->var = smalloc(strlen(name)+1);
+	strcpy(e->var, name);
+	e->val = 0;
+	e->len = 0;
+	e->qid.path = ++eg->path;
+	e->next = nil;
+	e->qid.vers = 0;
+	*le = e;
+	c->qid = e->qid;
+	eg->vers++;
+	poperror();
+	qunlock(eg);
+	c->offset = 0;
+	c->flag |= COPEN;
+	c->mode = mode;
+}
+
+static void
+envclose(Chan *c)
+{
+	if(c->flag & CRCLOSE)
+		envremove(c);
+}
+
+static long
+envread(Chan *c, void *a, long n, vlong offset)
+{
+	Egrp *eg;
+	Evalue *e;
+
+	if(c->qid.type & QTDIR)
+		return devdirread(c, a, n, 0, 0, envgen);
+	eg = up->env->egrp;
+	qlock(eg);
+	if(waserror()){
+		qunlock(eg);
+		nexterror();
+	}
+	for(e = eg->entries; e != nil; e = e->next)
+		if(e->qid.path == c->qid.path)
+			break;
+	if(e == nil)
+		error(Enonexist);
+	if(offset > e->len)	/* protects against overflow converting vlong to ulong */
+		n = 0;
+	else if(offset + n > e->len)
+		n = e->len - offset;
+	if(n <= 0)
+		n = 0;
+	else
+		memmove(a, e->val+offset, n);
+	poperror();
+	qunlock(eg);
+	return n;
+}
+
+static long
+envwrite(Chan *c, void *a, long n, vlong offset)
+{
+	char *s;
+	int ve;
+	Egrp *eg;
+	Evalue *e;
+
+	if(n <= 0)
+		return 0;
+	eg = up->env->egrp;
+	qlock(eg);
+	if(waserror()){
+		qunlock(eg);
+		nexterror();
+	}
+	for(e = eg->entries; e != nil; e = e->next)
+		if(e->qid.path == c->qid.path)
+			break;
+	if(e == nil)
+		error(Enonexist);
+	ve = offset+n;
+	if(ve > Maxenvsize)
+		error(Etoobig);
+	if(ve > e->len) {
+		s = smalloc(ve);
+		memmove(s, e->val, e->len);
+		if(e->val != nil)
+			free(e->val);
+		e->val = s;
+		e->len = ve;
+	}
+	memmove(e->val+offset, a, n);
+	e->qid.vers++;
+	poperror();
+	qunlock(eg);
+	return n;
+}
+
+static void
+envremove(Chan *c)
+{
+	Egrp *eg;
+	Evalue *e, **l;
+
+	if(c->qid.type & QTDIR)
+		error(Eperm);
+	eg = up->env->egrp;
+	qlock(eg);
+	for(l = &eg->entries; (e = *l) != nil; l = &e->next)
+		if(e->qid.path == c->qid.path)
+			break;
+	if(e == nil) {
+		qunlock(eg);
+		error(Enonexist);
+	}
+	*l = e->next;
+	eg->vers++;
+	qunlock(eg);
+	free(e->var);
+	if(e->val != nil)
+		free(e->val);
+	free(e);
+}
+
+Dev envdevtab = {
+	'e',
+	"env",
+
+	devreset,
+	devinit,
+	devshutdown,
+	envattach,
+	envwalk,
+	envstat,
+	envopen,
+	envcreate,
+	envclose,
+	envread,
+	devbread,
+	envwrite,
+	devbwrite,
+	envremove,
+	devwstat
+};
+
+/*
+ * kernel interface to environment variables
+ */
+Egrp*
+newegrp(void)
+{
+	Egrp	*e;
+
+	e = smalloc(sizeof(Egrp));
+	e->ref = 1;
+	return e;
+}
+
+void
+closeegrp(Egrp *e)
+{
+	Evalue *el, *nl;
+
+	if(e == nil || decref(e) != 0)
+		return;
+	for (el = e->entries; el != nil; el = nl) {
+		free(el->var);
+		if (el->val)
+			free(el->val);
+		nl = el->next;
+		free(el);
+	}
+	free(e);
+}
+
+void
+egrpcpy(Egrp *to, Egrp *from)
+{
+	Evalue *e, *ne, **last;
+
+	if(from == nil)
+		return;
+	last = &to->entries;
+	qlock(from);
+	for (e = from->entries; e != nil; e = e->next) {
+		ne = smalloc(sizeof(Evalue));
+		ne->var = smalloc(strlen(e->var)+1);
+		strcpy(ne->var, e->var);
+		if (e->val) {
+			ne->val = smalloc(e->len);
+			memmove(ne->val, e->val, e->len);
+			ne->len = e->len;
+		}
+		ne->qid.path = ++to->path;
+		*last = ne;
+		last = &ne->next;
+	}
+	qunlock(from);
+}
+
+void
+ksetenv(char *var, char *val, int)
+{
+	Chan *c;
+	char buf[2*KNAMELEN];
+
+	snprint(buf, sizeof(buf), "#e/%s", var);
+	if(waserror())
+		return;
+	c = namec(buf, Acreate, OWRITE, 0600);
+	poperror();
+	if(!waserror()){
+		if(!waserror()){
+			devtab[c->type]->write(c, val, strlen(val), 0);
+			poperror();
+		}
+		poperror();
+	}
+	cclose(c);
+}