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libstore: Make uploads with filetransfer.cc consume a RestartableSource

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Make uploads run in constant memory. Also change the callbacks to be
noexcept, since we really don't want to be unwinding the stack in the
curl thread. That will definitely corrupt that stack and make nix/curl
crash in very bad ways.
This commit is contained in:
Sergei Zimmerman 2025-10-29 01:29:09 +03:00 • committed by John Ericson
parent b8d7f551e4
commit cf75079bd8
9 changed files with 87 additions and 42 deletions
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42
src/libstore/filetransfer.cc
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@ -295,20 +295,17 @@ struct curlFileTransfer : public FileTransfer
return 0;
}
size_t readOffset = 0;
size_t readCallback(char * buffer, size_t size, size_t nitems)
{
if (readOffset == request.data->length())
return 0;
auto count = std::min(size * nitems, request.data->length() - readOffset);
assert(count);
memcpy(buffer, request.data->data() + readOffset, count);
readOffset += count;
return count;
size_t readCallback(char * buffer, size_t size, size_t nitems) noexcept
try {
auto data = request.data;
return data->source->read(buffer, nitems * size);
} catch (EndOfFile &) {
return 0;
} catch (...) {
return CURL_READFUNC_ABORT;
}
static size_t readCallbackWrapper(char * buffer, size_t size, size_t nitems, void * userp)
static size_t readCallbackWrapper(char * buffer, size_t size, size_t nitems, void * userp) noexcept
{
return ((TransferItem *) userp)->readCallback(buffer, size, nitems);
}
@ -322,19 +319,24 @@ struct curlFileTransfer : public FileTransfer
}
#endif
size_t seekCallback(curl_off_t offset, int origin)
{
size_t seekCallback(curl_off_t offset, int origin) noexcept
try {
auto source = request.data->source;
if (origin == SEEK_SET) {
readOffset = offset;
source->restart();
source->skip(offset);
} else if (origin == SEEK_CUR) {
readOffset += offset;
source->skip(offset);
} else if (origin == SEEK_END) {
readOffset = request.data->length() + offset;
NullSink sink{};
source->drainInto(sink);
}
return CURL_SEEKFUNC_OK;
} catch (...) {
return CURL_SEEKFUNC_FAIL;
}
static size_t seekCallbackWrapper(void * clientp, curl_off_t offset, int origin)
static size_t seekCallbackWrapper(void * clientp, curl_off_t offset, int origin) noexcept
{
return ((TransferItem *) clientp)->seekCallback(offset, origin);
}
@ -393,10 +395,10 @@ struct curlFileTransfer : public FileTransfer
if (request.data) {
if (request.method == HttpMethod::POST) {
curl_easy_setopt(req, CURLOPT_POST, 1L);
curl_easy_setopt(req, CURLOPT_POSTFIELDSIZE_LARGE, (curl_off_t) request.data->length());
curl_easy_setopt(req, CURLOPT_POSTFIELDSIZE_LARGE, (curl_off_t) request.data->sizeHint);
} else if (request.method == HttpMethod::PUT) {
curl_easy_setopt(req, CURLOPT_UPLOAD, 1L);
curl_easy_setopt(req, CURLOPT_INFILESIZE_LARGE, (curl_off_t) request.data->length());
curl_easy_setopt(req, CURLOPT_INFILESIZE_LARGE, (curl_off_t) request.data->sizeHint);
} else {
unreachable();
}