~kris/9hist: Plan 9 from Bell Labs 1990-08-21

10 files changed, 74 insertions(+), 59 deletions(-)

M gnot/chan.c
M gnot/dev.c
M gnot/fault.c
M gnot/mem.h
M gnot/sysfile.c
M port/chan.c
M port/dev.c
M port/fault.c
M port/sysfile.c
M power/mem.h

M gnot/chan.c => gnot/chan.c +23 -17

@@ 432,10 432,26 @@ namec(char *name, int amode, int omode, ulong perm)
 	Chan *c, *nc;
 	int t;
 	int mntok, isdot;
-	char *elem = u->elem;
+	char *p;
+	char *elem;
 
 	if(name[0] == 0)
 		error(0, Enonexist);
+
+	/*
+	 * Make sure all of name is o.k.  first byte is validated
+	 * externally so if it's a kernel address we know it's o.k.
+	 */
+	if(!((ulong)name & KZERO)){
+		p = name;
+		t = BY2PG-((ulong)p&(BY2PG-1));
+		while(vmemchr(p, 0, t) == 0){
+			p += t;
+			t = BY2PG;
+		}
+	}
+
+	elem = u->elem;
 	mntok = 1;
 	isdot = 0;
 	if(name[0] == '/'){


@@ 446,8 462,6 @@ namec(char *name, int amode, int omode, ulong perm)
 		name = skipslash(name);
 	}else if(name[0] == '#'){
 		mntok = 0;
-		if(!((ulong)name & KZERO))
-			validaddr((ulong)(name+1), 2, 0);
 		if(name[1]=='|' || name[1]=='M')
 			error(0, Enonexist);
 		t = devno(name[1], 1);


@@ 570,18 584,11 @@ char*
 skipslash(char *name)
 {
     Again:
-	while(*name == '/'){
-		if(((ulong)name&KZERO)==0 && (((ulong)name+1)&(BY2PG-1))==0)
-			validaddr((ulong)name+1, 1, 0);
+	while(*name == '/')
 		name++;
-	}
-	if(*name == '.'){
-		if(((ulong)name&KZERO)==0 && (((ulong)name+1)&(BY2PG-1))==0)
-			validaddr((ulong)name+1, 1, 0);
-		if(name[1]==0 || name[1]=='/'){
-			name++;
-			goto Again;
-		}
+	if(*name=='.' && (name[1]==0 || name[1]=='/')){
+		name++;
+		goto Again;
 	}
 	return name;
 }


@@ 600,7 607,6 @@ char isfrog[]={
  * name[0] should not be a slash.
  * Advance name to next element in path, copying current element into elem.
  * Return pointer to next element, skipping slashes.
- * &name[0] is known to be a valid address.
  */
 char*
 nextelem(char *name, char *elem)


@@ 610,9 616,9 @@ nextelem(char *name, char *elem)
 
 	if(*name == '/')
 		error(0, Efilename);
-	end = vmemchr(name, 0, NAMELEN);
+	end = memchr(name, 0, NAMELEN);
 	if(end == 0){
-		end = vmemchr(name, '/', NAMELEN);
+		end = memchr(name, '/', NAMELEN);
 		if(end == 0)
 			error(0, Efilename);
 	}else{

M gnot/dev.c => gnot/dev.c +5 -8

@@ 143,16 143,14 @@ devstat(Chan *c, char *db, Dirtab *tab, int ntab, Devgen *gen)
 long
 devdirread(Chan *c, char *d, long n, Dirtab *tab, int ntab, Devgen *gen)
 {
-	long k, l, m;
+	long k, m;
 	Dir dir;
 
 	k = c->offset/DIRLEN;
-	l = (c->offset+n)/DIRLEN;
-	n = 0;
-	for(m=k; m<l; k++)
+	for(m=0; m<n; k++)
 		switch((*gen)(c, tab, ntab, k, &dir)){
 		case -1:
-			return n;
+			return m;
 
 		case 0:
 			c->offset += DIRLEN;


@@ 160,12 158,11 @@ devdirread(Chan *c, char *d, long n, Dirtab *tab, int ntab, Devgen *gen)
 
 		case 1:
 			convD2M(&dir, d);
-			n += DIRLEN;
+			m += DIRLEN;
 			d += DIRLEN;
-			m++;
 			break;
 		}
-	return n;
+	return m;
 }
 
 Chan *

M gnot/fault.c => gnot/fault.c +6 -3

@@ 104,7 104,7 @@ fault(Ureg *ur, FFrame *f)
 			exit();
 		}
 		s = &u->p->seg[SSEG];
-		if(s->o==0 || addr<s->maxva-4*1024*1024 || addr>=s->maxva)
+		if(s->o==0 || addr<s->maxva-USTACKSIZE || addr>=s->maxva)
 			goto cant;
 		/* grow stack */
 		o = s->o;


@@ 296,8 296,11 @@ validaddr(ulong addr, ulong len, int write)
 	}
     Again:
 	s = seg(u->p, addr);
-	if(s==0)
-		goto Err;
+	if(s==0){
+		s = &u->p->seg[SSEG];
+		if(s->o==0 || addr<s->maxva-USTACKSIZE || addr>=s->maxva)
+			goto Err;
+	}
 	if(write && (s->o->flag&OWRPERM)==0)
 		goto Err;
 	if(addr+len > s->maxva){

M gnot/mem.h => gnot/mem.h +1 -0

@@ 95,6 95,7 @@
 #define	USTKTOP	(TSTKTOP-100*BY2PG)	/* byte just beyond user stack */
 #define	KZERO	KSEG			/* base of kernel address space */
 #define	KTZERO	(KZERO+BY2PG)		/* first address in kernel text */
+#define	USTACKSIZE	(4*1024*1024)	/* size of user stack */
 
 #define	NSEG		5
 #define	MACHSIZE	4096

M gnot/sysfile.c => gnot/sysfile.c +2 -1

@@ 148,6 148,7 @@ unionread(Chan *c, void *va, long n)
 	nc = (*devtab[nc->type].open)(nc, OREAD);
 	nc->offset = c->offset;
 	nr = (*devtab[nc->type].read)(nc, va, n);
+	c->offset = nc->offset;		/* devdirread e.g. changes it */
 	close(nc);
 	poperror();
 	if(nr > 0)


@@ 192,7 193,7 @@ sysread(ulong *arg)
 		if(c->offset%DIRLEN || n==0)
 			error(0, Ebaddirread);
 	}
-	if((c->qid&CHDIR) && c->flag&CMOUNT)
+	if((c->qid&CHDIR) && (c->flag&CMOUNT))
 		n = unionread(c, (void*)arg[1], n);
 	else
 		n = (*devtab[c->type].read)(c, (void*)arg[1], n);

M port/chan.c => port/chan.c +23 -17

@@ 432,10 432,26 @@ namec(char *name, int amode, int omode, ulong perm)
 	Chan *c, *nc;
 	int t;
 	int mntok, isdot;
-	char *elem = u->elem;
+	char *p;
+	char *elem;
 
 	if(name[0] == 0)
 		error(0, Enonexist);
+
+	/*
+	 * Make sure all of name is o.k.  first byte is validated
+	 * externally so if it's a kernel address we know it's o.k.
+	 */
+	if(!((ulong)name & KZERO)){
+		p = name;
+		t = BY2PG-((ulong)p&(BY2PG-1));
+		while(vmemchr(p, 0, t) == 0){
+			p += t;
+			t = BY2PG;
+		}
+	}
+
+	elem = u->elem;
 	mntok = 1;
 	isdot = 0;
 	if(name[0] == '/'){


@@ 446,8 462,6 @@ namec(char *name, int amode, int omode, ulong perm)
 		name = skipslash(name);
 	}else if(name[0] == '#'){
 		mntok = 0;
-		if(!((ulong)name & KZERO))
-			validaddr((ulong)(name+1), 2, 0);
 		if(name[1]=='|' || name[1]=='M')
 			error(0, Enonexist);
 		t = devno(name[1], 1);


@@ 570,18 584,11 @@ char*
 skipslash(char *name)
 {
     Again:
-	while(*name == '/'){
-		if(((ulong)name&KZERO)==0 && (((ulong)name+1)&(BY2PG-1))==0)
-			validaddr((ulong)name+1, 1, 0);
+	while(*name == '/')
 		name++;
-	}
-	if(*name == '.'){
-		if(((ulong)name&KZERO)==0 && (((ulong)name+1)&(BY2PG-1))==0)
-			validaddr((ulong)name+1, 1, 0);
-		if(name[1]==0 || name[1]=='/'){
-			name++;
-			goto Again;
-		}
+	if(*name=='.' && (name[1]==0 || name[1]=='/')){
+		name++;
+		goto Again;
 	}
 	return name;
 }


@@ 600,7 607,6 @@ char isfrog[]={
  * name[0] should not be a slash.
  * Advance name to next element in path, copying current element into elem.
  * Return pointer to next element, skipping slashes.
- * &name[0] is known to be a valid address.
  */
 char*
 nextelem(char *name, char *elem)


@@ 610,9 616,9 @@ nextelem(char *name, char *elem)
 
 	if(*name == '/')
 		error(0, Efilename);
-	end = vmemchr(name, 0, NAMELEN);
+	end = memchr(name, 0, NAMELEN);
 	if(end == 0){
-		end = vmemchr(name, '/', NAMELEN);
+		end = memchr(name, '/', NAMELEN);
 		if(end == 0)
 			error(0, Efilename);
 	}else{

M port/dev.c => port/dev.c +5 -8

@@ 143,16 143,14 @@ devstat(Chan *c, char *db, Dirtab *tab, int ntab, Devgen *gen)
 long
 devdirread(Chan *c, char *d, long n, Dirtab *tab, int ntab, Devgen *gen)
 {
-	long k, l, m;
+	long k, m;
 	Dir dir;
 
 	k = c->offset/DIRLEN;
-	l = (c->offset+n)/DIRLEN;
-	n = 0;
-	for(m=k; m<l; k++)
+	for(m=0; m<n; k++)
 		switch((*gen)(c, tab, ntab, k, &dir)){
 		case -1:
-			return n;
+			return m;
 
 		case 0:
 			c->offset += DIRLEN;


@@ 160,12 158,11 @@ devdirread(Chan *c, char *d, long n, Dirtab *tab, int ntab, Devgen *gen)
 
 		case 1:
 			convD2M(&dir, d);
-			n += DIRLEN;
+			m += DIRLEN;
 			d += DIRLEN;
-			m++;
 			break;
 		}
-	return n;
+	return m;
 }
 
 Chan *

M port/fault.c => port/fault.c +6 -3

@@ 38,7 38,7 @@ fault(Ureg *ur, int user, int code)
 			panic("fault");
 		}
 		s = &u->p->seg[SSEG];
-		if(s->o==0 || addr<s->maxva-4*1024*1024 || addr>=s->maxva)
+		if(s->o==0 || addr<s->maxva-USTACKSIZE || addr>=s->maxva)
 			goto cant;
 		/* grow stack */
 		o = s->o;


@@ 223,8 223,11 @@ validaddr(ulong addr, ulong len, int write)
 	}
     Again:
 	s = seg(u->p, addr);
-	if(s==0)
-		goto Err;
+	if(s==0){
+		s = &u->p->seg[SSEG];
+		if(s->o==0 || addr<s->maxva-USTACKSIZE || addr>=s->maxva)
+			goto Err;
+	}
 	if(write && (s->o->flag&OWRPERM)==0)
 		goto Err;
 	if(addr+len > s->maxva){

M port/sysfile.c => port/sysfile.c +2 -1

@@ 148,6 148,7 @@ unionread(Chan *c, void *va, long n)
 	nc = (*devtab[nc->type].open)(nc, OREAD);
 	nc->offset = c->offset;
 	nr = (*devtab[nc->type].read)(nc, va, n);
+	c->offset = nc->offset;		/* devdirread e.g. changes it */
 	close(nc);
 	poperror();
 	if(nr > 0)


@@ 192,7 193,7 @@ sysread(ulong *arg)
 		if(c->offset%DIRLEN || n==0)
 			error(0, Ebaddirread);
 	}
-	if((c->qid&CHDIR) && c->flag&CMOUNT)
+	if((c->qid&CHDIR) && (c->flag&CMOUNT))
 		n = unionread(c, (void*)arg[1], n);
 	else
 		n = (*devtab[c->type].read)(c, (void*)arg[1], n);

M power/mem.h => power/mem.h +1 -1

@@ 110,7 110,7 @@
 #define	TSTKTOP	(USERADDR+100*BY2PG)	/* top of temporary stack */
 #define	KZERO	KSEG0			/* base of kernel address space */
 #define	KTZERO	(KSEG0+0x20000)		/* first address in kernel text */
-
+#define	USTACKSIZE	(4*1024*1024)	/* size of user stack */
 /*
  * Exception codes
  */

~kris/9p

9hist