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libaml: allow amlmapio() to re-enter the interpreter (can happen by pciadd() -> amleval())

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- make frame base pointer variable
- in rwreg(), save/restore the interpreter state and allocate a Frame* on the stack
- add overflow checks for frame base pointer to xec() and amleval()
- gc() scans the whole stack from FP to the *real* bottom F0
This commit is contained in:
cinap_lenrek 2018-11-04 19:48:27 +01:00
parent 89c659d80b
commit 93e493f391
1 changed files with 26 additions and 8 deletions
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34
sys/src/libaml/aml.c
View file

@ -123,14 +123,17 @@ struct Frame {
struct Interp {
uchar *pc;
Frame *fp;
Frame *fb;
};
static Interp interp;
static Frame stack[32];
#define PC interp.pc
#define PC interp.pc
#define FP interp.fp
#define FB stack
#define FB interp.fb
#define F0 stack
#define FT &stack[nelem(stack)]
static Heap *hp;
@ -234,7 +237,7 @@ gc(void)
if(h->mark & 2)
gcmark(H2D(h));
for(f = FP; f >= FB; f--){
for(f = FP; f >= F0; f--){
for(i=0; i<f->narg; i++)
gcmark(f->arg[i]);
gcmark(f->env);
@ -485,9 +488,13 @@ putle(uchar *p, int len, uvlong v)
static uvlong
rwreg(void *reg, int off, int len, uvlong v, int write)
{
Interp save;
uchar buf[8], *p;
Region *r;
save = interp; /* save, in case we reenter the interpreter */
FB = FP+1; /* allocate new base */
switch(TAG(reg)){
case 'b':
p = reg;
@ -498,7 +505,7 @@ rwreg(void *reg, int off, int len, uvlong v, int write)
putle(p, len, v);
else
v = getle(p, len);
return v;
goto Out;
case 'r':
r = reg;
@ -547,10 +554,13 @@ rwreg(void *reg, int off, int len, uvlong v, int write)
(Name*)r->name, spacename[r->space],
r->off, off, len, v);
}
return v;
goto Out;
}
return ~0;
v = -1;
Out:
interp = save; /* restore */
return v;
}
static uvlong
@ -937,6 +947,8 @@ xec(uchar *pc, uchar *end, Name *dot, Env *env, void **pret)
void *r;
PC = pc;
if(FB < F0 || FB >= FT)
goto Out;
FP = FB;
FP->tag = 0;
@ -946,7 +958,7 @@ xec(uchar *pc, uchar *end, Name *dot, Env *env, void **pret)
FP->start = PC;
FP->end = end;
FP->aux = end;
FB->ref = nil;
FP->ref = nil;
FP->dot = dot;
FP->env = env;
FP->op = nil;
@ -2153,6 +2165,9 @@ amlinit(void)
{
Name *n;
FB = F0;
FP = F0-1;
fmtinstall('V', Vfmt);
fmtinstall('N', Nfmt);
@ -2190,7 +2205,8 @@ void
amlexit(void)
{
amlroot = nil;
FP = FB-1;
FB = F0;
FP = F0-1;
gc();
}
@ -2269,6 +2285,8 @@ amleval(void *dot, char *fmt, ...)
return -1;
if(m->eval == nil)
return xec(m->start, m->end, forkname(m->name), e, r);
if(FB < F0 || FB >= FT)
return -1;
FP = FB;
FP->op = nil;
FP->env = e;