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(v6.x backport) dns: fix crash while using dns.setServers after dns.resolve4 #13724

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(v6.x backport) dns: fix crash while using dns.setServers after dns.resolve4 #13724

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510e626
dns: fix crash using dns.setServers after resolve4
XadillaX May 17, 2017
9d69519
make it compilable
XadillaX Jun 16, 2017
4244c21
update after @addaleax's reviewing
XadillaX Jun 22, 2017
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17 changes: 10 additions & 7 deletions src/cares_wrap.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -318,7 +318,7 @@ void cares_wrap_hostent_cpy(struct hostent* dest, struct hostent* src) {

/* copy `h_name` */
size_t name_size = strlen(src->h_name) + 1;
dest->h_name = node::Malloc<char>(name_size);
dest->h_name = reinterpret_cast<char*>(node::Malloc(name_size));
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@addaleax addaleax Jun 21, 2017

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Can you avoid reinterpret_cast when a static_cast does the job just fine? Alternatively, you could also backport the overloads of node::Malloc & similar methods as they are on master, that would help with backporting other patches in the future.

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@XadillaX XadillaX Jun 21, 2017

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@addaleax #8482 it shows dont-land-on-v6.x and v4.x. May I still make a backport for it?

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@addaleax addaleax Jun 21, 2017

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@XadillaX Yes, you’ll just need to try and see how to resolve the conflicts that you’re going to get. I suspect that will be a bit of work, so only do that if you have the time; for now, just changing to static_cast here is definitely easier. :)

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@XadillaX XadillaX Jun 22, 2017

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@addaleax I found a backport chain for #8482, it will be a big backport. So I decide to only backport this PR but not #8482 and its dependencies.

memcpy(dest->h_name, src->h_name, name_size);

/* copy `h_aliases` */
Expand All @@ -329,10 +329,12 @@ void cares_wrap_hostent_cpy(struct hostent* dest, struct hostent* src) {
alias_count++) {
}

dest->h_aliases = node::Malloc<char*>(alias_count + 1);
dest->h_aliases = reinterpret_cast<char**>(node::Malloc((alias_count + 1) *
sizeof(char*)));
for (size_t i = 0; i < alias_count; i++) {
cur_alias_length = strlen(src->h_aliases[i]);
dest->h_aliases[i] = node::Malloc(cur_alias_length + 1);
dest->h_aliases[i] = reinterpret_cast<char*>(node::Malloc(cur_alias_length +
1));
memcpy(dest->h_aliases[i], src->h_aliases[i], cur_alias_length + 1);
}
dest->h_aliases[alias_count] = nullptr;
Expand All @@ -344,9 +346,10 @@ void cares_wrap_hostent_cpy(struct hostent* dest, struct hostent* src) {
list_count++) {
}

dest->h_addr_list = node::Malloc<char*>(list_count + 1);
dest->h_addr_list = reinterpret_cast<char**>(node::Malloc((list_count + 1) *
sizeof(char*)));
for (size_t i = 0; i < list_count; i++) {
dest->h_addr_list[i] = node::Malloc(src->h_length);
dest->h_addr_list[i] = reinterpret_cast<char*>(node::Malloc(src->h_length));
memcpy(dest->h_addr_list[i], src->h_addr_list[i], src->h_length);
}
dest->h_addr_list[list_count] = nullptr;
Expand Down Expand Up @@ -435,7 +438,7 @@ class QueryWrap : public AsyncWrap {

unsigned char* buf_copy = nullptr;
if (status == ARES_SUCCESS) {
buf_copy = node::Malloc<unsigned char>(answer_len);
buf_copy = reinterpret_cast<unsigned char*>(node::Malloc(answer_len));
memcpy(buf_copy, answer_buf, answer_len);
}

Expand All @@ -459,7 +462,7 @@ class QueryWrap : public AsyncWrap {

struct hostent* host_copy = nullptr;
if (status == ARES_SUCCESS) {
host_copy = node::Malloc<hostent>(1);
host_copy = reinterpret_cast<hostent*>(node::Malloc(sizeof(hostent)));
cares_wrap_hostent_cpy(host_copy, host);
}

Expand Down