Fixed enif_release_resource bug
I was accidentally calling enif_release_resource too many times if the
NIF call had previously yielded back to the Erlang VM. For some reason
this works fine on R14B01 but not on R16B02. The fix was simply to add a
field to the resource struct that tracks if its already been released.
This also changes the target binary allocation to not have to allocate
room for the ErlNifBinary struct since we're adding released flags. This
is a minor performance optimization which avoids a malloc/free call per
encode or decode invocation.
diff --git a/c_src/b64url.c b/c_src/b64url.c
index 5e48957..604f21a 100644
--- a/c_src/b64url.c
+++ b/c_src/b64url.c
@@ -24,10 +24,12 @@
typedef struct
{
ErlNifPid pid;
- ErlNifBinary* tgt;
+ ErlNifBinary tgt;
size_t len;
size_t si;
size_t ti;
+ char res_released;
+ char bin_released;
} b64url_st;
@@ -162,12 +164,10 @@
st->len = src->size;
st->si = 0;
st->ti = 0;
- st->tgt = (ErlNifBinary*) enif_alloc(sizeof(ErlNifBinary));
- if(st->tgt == NULL) {
- goto error;
- }
+ st->res_released = 0;
+ st->bin_released = 0;
- if(!enif_alloc_binary(tlen, st->tgt)) {
+ if(!enif_alloc_binary(tlen, &(st->tgt))) {
goto error;
}
@@ -175,6 +175,7 @@
error:
if(st != NULL) {
+ st->res_released = 1;
enif_release_resource(st);
}
return NULL;
@@ -186,9 +187,8 @@
{
b64url_st* st = (b64url_st*) obj;
- if(st->tgt != NULL) {
- enif_release_binary(st->tgt);
- enif_free(st->tgt);
+ if(!st->bin_released) {
+ enif_release_binary(&(st->tgt));
}
}
@@ -199,9 +199,8 @@
ENTERM ret;
if(status == ST_OK) {
- ret = make_ok(env, priv, enif_make_binary(env, st->tgt));
- enif_free(st->tgt);
- st->tgt = NULL;
+ ret = make_ok(env, priv, enif_make_binary(env, &(st->tgt)));
+ st->bin_released = 1;
} else if(status == ST_PARTIAL) {
ret = make_partial(env, priv, enif_make_resource(env, st));
} else {
@@ -209,7 +208,11 @@
ret = enif_make_badarg(env);
}
- enif_release_resource(st);
+ if(!st->res_released) {
+ st->res_released = 1;
+ enif_release_resource(st);
+ }
+
return ret;
}
@@ -219,9 +222,8 @@
b64url_priv* priv = (b64url_priv*) enif_priv_data(env);
if(status == ST_OK) {
- ret = make_ok(env, priv, enif_make_binary(env, st->tgt));
- enif_free(st->tgt);
- st->tgt = NULL;
+ ret = make_ok(env, priv, enif_make_binary(env, &(st->tgt)));
+ st->bin_released = 1;
} else if(status == ST_ERROR) {
ret = make_error(env, priv, ret);
} else if(status == ST_PARTIAL) {
@@ -231,7 +233,11 @@
ret = enif_make_badarg(env);
}
- enif_release_resource(st);
+ if(!st->res_released) {
+ st->res_released = 1;
+ enif_release_resource(st);
+ }
+
return ret;
}
@@ -291,6 +297,7 @@
b64url_encode(ErlNifEnv* env, ErlNifBinary* src, b64url_st* st)
{
size_t chunk_start = st->si;
+ size_t rem;
unsigned char c1;
unsigned char c2;
unsigned char c3;
@@ -303,10 +310,10 @@
c2 = src->data[st->si++];
c3 = src->data[st->si++];
- st->tgt->data[st->ti++] = B64URL_B2A[(c1 >> 2) & 0x3F];
- st->tgt->data[st->ti++] = B64URL_B2A[((c1 << 4) | (c2 >> 4)) & 0x3F];
- st->tgt->data[st->ti++] = B64URL_B2A[((c2 << 2) | (c3 >> 6)) & 0x3F];
- st->tgt->data[st->ti++] = B64URL_B2A[c3 & 0x3F];
+ st->tgt.data[st->ti++] = B64URL_B2A[(c1 >> 2) & 0x3F];
+ st->tgt.data[st->ti++] = B64URL_B2A[((c1 << 4) | (c2 >> 4)) & 0x3F];
+ st->tgt.data[st->ti++] = B64URL_B2A[((c2 << 2) | (c3 >> 6)) & 0x3F];
+ st->tgt.data[st->ti++] = B64URL_B2A[c3 & 0x3F];
if(st->si - chunk_start > BYTES_PER_PERCENT) {
if(do_consume_timeslice(env)) {
@@ -317,17 +324,18 @@
}
}
- if(src->size % 3 == 1) {
+ rem = src->size % 3;
+ if(rem == 1) {
c1 = src->data[st->si];
- st->tgt->data[st->ti++] = B64URL_B2A[(c1 >> 2) & 0x3F];
- st->tgt->data[st->ti++] = B64URL_B2A[(c1 << 4) & 0x3F];
- } else if(src->size % 3 == 2) {
+ st->tgt.data[st->ti++] = B64URL_B2A[(c1 >> 2) & 0x3F];
+ st->tgt.data[st->ti++] = B64URL_B2A[(c1 << 4) & 0x3F];
+ } else if(rem == 2) {
c1 = src->data[st->si];
c2 = src->data[st->si+1];
- st->tgt->data[st->ti++] = B64URL_B2A[(c1 >> 2) & 0x3F];
- st->tgt->data[st->ti++] = B64URL_B2A[((c1 << 4) | (c2 >> 4)) & 0x3F];
- st->tgt->data[st->ti++] = B64URL_B2A[(c2 << 2) & 0x3F];
- } else {
+ st->tgt.data[st->ti++] = B64URL_B2A[(c1 >> 2) & 0x3F];
+ st->tgt.data[st->ti++] = B64URL_B2A[((c1 << 4) | (c2 >> 4)) & 0x3F];
+ st->tgt.data[st->ti++] = B64URL_B2A[(c2 << 2) & 0x3F];
+ } else if(rem != 0) {
assert(0 == 1 && "Inavlid length calculation");
}
@@ -378,6 +386,7 @@
error:
if(st != NULL) {
+ st->res_released = 1;
enif_release_resource(st);
}
@@ -424,6 +433,7 @@
{
b64url_priv* priv = (b64url_priv*) enif_priv_data(env);
size_t chunk_start = st->si;
+ size_t rem;
unsigned char c1;
unsigned char c2;
unsigned char c3;
@@ -443,9 +453,9 @@
return ST_ERROR;
}
- st->tgt->data[st->ti++] = (c1 << 2) | (c2 >> 4);
- st->tgt->data[st->ti++] = (c2 << 4) | (c3 >> 2);
- st->tgt->data[st->ti++] = (c3 << 6) | c4;
+ st->tgt.data[st->ti++] = (c1 << 2) | (c2 >> 4);
+ st->tgt.data[st->ti++] = (c2 << 4) | (c3 >> 2);
+ st->tgt.data[st->ti++] = (c3 << 6) | c4;
if(st->si - chunk_start > BYTES_PER_PERCENT) {
if(do_consume_timeslice(env)) {
@@ -456,7 +466,8 @@
}
}
- if(src->size % 4 == 2) {
+ rem = src->size % 4;
+ if(rem == 2) {
c1 = B64URL_A2B[src->data[st->si]];
c2 = B64URL_A2B[src->data[st->si+1]];
@@ -465,8 +476,8 @@
return ST_ERROR;
}
- st->tgt->data[st->ti++] = (c1 << 2) | (c2 >> 4);
- } else if(src->size % 4 == 3) {
+ st->tgt.data[st->ti++] = (c1 << 2) | (c2 >> 4);
+ } else if(rem == 3) {
c1 = B64URL_A2B[src->data[st->si]];
c2 = B64URL_A2B[src->data[st->si+1]];
c3 = B64URL_A2B[src->data[st->si+2]];
@@ -476,9 +487,9 @@
return ST_ERROR;
}
- st->tgt->data[st->ti++] = (c1 << 2) | (c2 >> 4);
- st->tgt->data[st->ti++] = (c2 << 4) | (c3 >> 2);
- } else {
+ st->tgt.data[st->ti++] = (c1 << 2) | (c2 >> 4);
+ st->tgt.data[st->ti++] = (c2 << 4) | (c3 >> 2);
+ } else if(rem != 0) {
assert(0 == 1 && "invalid source length");
}
@@ -529,6 +540,7 @@
error:
if(st != NULL) {
+ st->res_released = 1;
enif_release_resource(st);
}
