gc: more cleanup
* disallow surrogate pair runes.
* diagnose impossible type assertions
* eliminate another static buffer.
* do not overflow lexbuf.
* add -u flag to disable package unsafe.
R=ken2
CC=golang-dev
https://golang.org/cl/1619042
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 18e87f0..2cf408e 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -659,6 +659,7 @@
EXTERN Biobuf* bout;
EXTERN int nerrors;
EXTERN int nsyntaxerrors;
+EXTERN int safemode;
EXTERN char namebuf[NSYMB];
EXTERN char lexbuf[NSYMB];
EXTERN char debug[256];
diff --git a/src/cmd/gc/lex.c b/src/cmd/gc/lex.c
index 7f85271..5dc6d78 100644
--- a/src/cmd/gc/lex.c
+++ b/src/cmd/gc/lex.c
@@ -21,6 +21,26 @@
EOF = -1,
};
+void
+usage(void)
+{
+ print("usage: %cg [flags] file.go...\n");
+ print("flags:\n");
+ // -A is allow use of "any" type, for bootstrapping
+ print(" -I DIR search for packages in DIR\n");
+ print(" -d print declarations\n");
+ print(" -e no limit on number of errors printed\n");
+ print(" -f print stack frame structure\n");
+ print(" -h panic on an error\n");
+ print(" -o file specify output file\n");
+ print(" -S print the assembly language\n");
+ print(" -V print the compiler version\n");
+ print(" -u disable package unsafe\n");
+ print(" -w print the parse tree after typing\n");
+ print(" -x print lex tokens\n");
+ exit(0);
+}
+
int
main(int argc, char *argv[])
{
@@ -62,19 +82,24 @@
break;
case 'o':
- outfile = ARGF();
+ outfile = EARGF(usage());
break;
case 'I':
- addidir(ARGF());
+ addidir(EARGF(usage()));
break;
+
+ case 'u':
+ safemode = 1;
+ break;
+
case 'V':
print("%cg version %s\n", thechar, getgoversion());
- errorexit();
+ exit(0);
} ARGEND
if(argc < 1)
- goto usage;
+ usage();
// special flag to detect compilation of package runtime
compiling_runtime = debug['+'];
@@ -188,22 +213,6 @@
flusherrors();
exit(0);
return 0;
-
-usage:
- print("flags:\n");
- // -A is allow use of "any" type, for bootstrapping
- print(" -I DIR search for packages in DIR\n");
- print(" -d print declarations\n");
- print(" -e no limit on number of errors printed\n");
- print(" -f print stack frame structure\n");
- print(" -h panic on an error\n");
- print(" -o file specify output file\n");
- print(" -S print the assembly language\n");
- print(" -V print the compiler version\n");
- print(" -w print the parse tree after typing\n");
- print(" -x print lex tokens\n");
- exit(0);
- return 0;
}
int
@@ -336,6 +345,10 @@
}
if(strcmp(f->u.sval->s, "unsafe") == 0) {
+ if(safemode) {
+ yyerror("cannot import package unsafe");
+ errorexit();
+ }
importpkg = mkpkg(f->u.sval);
cannedimports("unsafe.6", unsafeimport);
return;
@@ -461,7 +474,7 @@
{
int c, c1, clen, escflag, ncp;
vlong v;
- char *cp;
+ char *cp, *ep;
Rune rune;
Sym *s;
static Loophack *lstk;
@@ -485,11 +498,13 @@
if(c >= Runeself) {
/* all multibyte runes are alpha */
cp = lexbuf;
+ ep = lexbuf+sizeof lexbuf;
goto talph;
}
if(isalpha(c)) {
cp = lexbuf;
+ ep = lexbuf+sizeof lexbuf;
goto talph;
}
@@ -504,12 +519,14 @@
case '_':
cp = lexbuf;
+ ep = lexbuf+sizeof lexbuf;
goto talph;
case '.':
c1 = getc();
if(isdigit(c1)) {
cp = lexbuf;
+ ep = lexbuf+sizeof lexbuf;
*cp++ = c;
c = c1;
c1 = 0;
@@ -862,6 +879,10 @@
* prefix has been stored
*/
for(;;) {
+ if(cp+10 >= ep) {
+ yyerror("identifier too long");
+ errorexit();
+ }
if(c >= Runeself) {
ungetc(c);
rune = getr();
@@ -898,8 +919,13 @@
tnum:
c1 = 0;
cp = lexbuf;
+ ep = lexbuf+sizeof lexbuf;
if(c != '0') {
for(;;) {
+ if(cp+10 >= ep) {
+ yyerror("identifier too long");
+ errorexit();
+ }
*cp++ = c;
c = getc();
if(isdigit(c))
@@ -911,6 +937,10 @@
c = getc();
if(c == 'x' || c == 'X') {
for(;;) {
+ if(cp+10 >= ep) {
+ yyerror("identifier too long");
+ errorexit();
+ }
*cp++ = c;
c = getc();
if(isdigit(c))
@@ -930,6 +960,10 @@
c1 = 0;
for(;;) {
+ if(cp+10 >= ep) {
+ yyerror("identifier too long");
+ errorexit();
+ }
if(!isdigit(c))
break;
if(c < '0' || c > '7')
@@ -973,6 +1007,10 @@
casedot:
for(;;) {
+ if(cp+10 >= ep) {
+ yyerror("identifier too long");
+ errorexit();
+ }
*cp++ = c;
c = getc();
if(!isdigit(c))
@@ -993,6 +1031,10 @@
if(!isdigit(c))
yyerror("malformed fp constant exponent");
while(isdigit(c)) {
+ if(cp+10 >= ep) {
+ yyerror("identifier too long");
+ errorexit();
+ }
*cp++ = c;
c = getc();
}
@@ -1010,6 +1052,10 @@
if(!isdigit(c))
yyerror("malformed fp constant exponent");
while(isdigit(c)) {
+ if(cp+10 >= ep) {
+ yyerror("identifier too long");
+ errorexit();
+ }
*cp++ = c;
c = getc();
}
@@ -1254,7 +1300,7 @@
ungetc(c);
break;
}
- if(u && l > Runemax) {
+ if(u && (l > Runemax || (0xd800 <= l && l < 0xe000))) {
yyerror("invalid Unicode code point in escape sequence: %#llx", l);
l = Runeerror;
}
diff --git a/src/cmd/gc/subr.c b/src/cmd/gc/subr.c
index 96d0361..649b8f5 100644
--- a/src/cmd/gc/subr.c
+++ b/src/cmd/gc/subr.c
@@ -877,7 +877,6 @@
int
Lconv(Fmt *fp)
{
- char str[STRINGSZ], s[STRINGSZ];
struct
{
Hist* incl; /* start of this include file */
@@ -917,29 +916,25 @@
if(n > HISTSZ)
n = HISTSZ;
- str[0] = 0;
for(i=n-1; i>=0; i--) {
if(i != n-1) {
if(fp->flags & ~(FmtWidth|FmtPrec))
break;
- strcat(str, " ");
+ fmtprint(fp, " ");
}
if(a[i].line)
- snprint(s, STRINGSZ, "%s:%ld[%s:%ld]",
+ fmtprint(fp, "%s:%ld[%s:%ld]",
a[i].line->name, lno-a[i].ldel+1,
a[i].incl->name, lno-a[i].idel+1);
else
- snprint(s, STRINGSZ, "%s:%ld",
+ fmtprint(fp, "%s:%ld",
a[i].incl->name, lno-a[i].idel+1);
- if(strlen(s)+strlen(str) >= STRINGSZ-10)
- break;
- strcat(str, s);
lno = a[i].incl->line - 1; /* now print out start of this file */
}
if(n == 0)
- strcat(str, "<epoch>");
+ fmtprint(fp, "<epoch>");
- return fmtstrcpy(fp, str);
+ return 0;
}
/*
@@ -1135,10 +1130,10 @@
Type *t1;
Sym *s;
- if(debug['U']) {
- debug['U'] = 0;
+ if(debug['r']) {
+ debug['r'] = 0;
fmtprint(fp, "%T (orig=%T)", t, t->orig);
- debug['U'] = 1;
+ debug['r'] = 1;
return 0;
}
@@ -1871,6 +1866,11 @@
if(why != nil)
*why = "";
+ if(safemode && (isptrto(src, TANY) || isptrto(dst, TANY))) {
+ yyerror("cannot use unsafe.Pointer");
+ errorexit();
+ }
+
if(src == dst)
return OCONVNOP;
if(src == T || dst == T || src->etype == TFORW || dst->etype == TFORW || src->orig == T || dst->orig == T)
@@ -1894,7 +1894,8 @@
*why = smprint(": %T is pointer to interface, not interface", src);
else if(have)
*why = smprint(": %T does not implement %T (wrong type for %S method)\n"
- "\thave %T\n\twant %T", src, dst, missing->sym, have->type, missing->type);
+ "\thave %S%hhT\n\twant %S%hhT", src, dst, missing->sym,
+ have->sym, have->type, missing->sym, missing->type);
else
*why = smprint(": %T does not implement %T (missing %S method)",
src, dst, missing->sym);
@@ -2031,7 +2032,6 @@
// 9. src is unsafe.Pointer and dst is a pointer or uintptr.
if(isptrto(src, TANY) && (isptr[dst->etype] || dst->etype == TUINTPTR))
return OCONVNOP;
-
return 0;
}
diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index d285ad0..592166c 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -52,7 +52,7 @@
Node *n, *l, *r;
NodeList *args;
int lno, ok, ntop;
- Type *t;
+ Type *t, *missing, *have;
Sym *sym;
Val v;
char *why;
@@ -521,6 +521,18 @@
if(n->type == T)
goto error;
}
+ if(n->type != T && n->type->etype != TINTER)
+ if(!implements(n->type, t, &missing, &have)) {
+ if(have)
+ yyerror("impossible type assertion: %+N cannot have dynamic type %T"
+ " (wrong type for %S method)\n\thave %S%hhT\n\twant %S%hhT",
+ l, n->type, missing->sym, have->sym, have->type,
+ missing->sym, missing->type);
+ else
+ yyerror("impossible type assertion: %+N cannot have dynamic type %T"
+ " (missing %S method)", l, n->type, missing->sym);
+ goto error;
+ }
goto ret;
case OINDEX:
@@ -1179,6 +1191,8 @@
checkwidth(t);
}
}
+ if(safemode && isptrto(t, TANY))
+ yyerror("cannot use unsafe.Pointer");
evconst(n);
if(n->op == OTYPE && !(top & Etype)) {
diff --git a/src/cmd/gc/unsafe.c b/src/cmd/gc/unsafe.c
index 423fc08..dbf6f70 100644
--- a/src/cmd/gc/unsafe.c
+++ b/src/cmd/gc/unsafe.c
@@ -19,7 +19,7 @@
long v;
Val val;
- if(fn == N || fn->op != ONAME || (s = fn->sym) == S)
+ if(safemode || fn == N || fn->op != ONAME || (s = fn->sym) == S)
goto no;
if(s->pkg != unsafepkg)
goto no;
diff --git a/test/interface/explicit.go b/test/interface/explicit.go
index 797cec8..120135c 100644
--- a/test/interface/explicit.go
+++ b/test/interface/explicit.go
@@ -1,4 +1,4 @@
-// errchk $G $D/$F.go
+// errchk $G -e $D/$F.go
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
@@ -50,3 +50,22 @@
e = E(t) // ok
t = T(e) // ERROR "need explicit|need type assertion|incompatible"
}
+
+type M interface { M() }
+var m M
+
+var _ = m.(int) // ERROR "impossible type assertion"
+
+type Int int
+func (Int) M(float) {}
+
+var _ = m.(Int) // ERROR "impossible type assertion"
+
+var ii int
+var jj Int
+
+var m1 M = ii // ERROR "missing"
+var m2 M = jj // ERROR "wrong type for M method"
+
+var m3 = M(ii) // ERROR "missing"
+var m4 = M(jj) // ERROR "wrong type for M method"
