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derivations.cc: Use larger buffer in printString

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If we want to be careful about hitting the stack protector page, we should use `-fstack-check` instead.

Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
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Robert Hensing 2022-01-21 17:25:37 +01:00 committed by GitHub
parent dec7748119
commit 0407436b0f
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1 changed files with 1 additions and 9 deletions
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src/libstore/derivations.cc
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@ -273,15 +273,7 @@ Derivation parseDerivation(const Store & store, std::string && s, std::string_vi
static void printString(string & res, std::string_view s) static void printString(string & res, std::string_view s)
{ {
// Large stack allocations can skip past the stack protection page. boost::container::small_vector<char, 64 * 1024> buffer;
const size_t stack_protection_size = 4096;
// We reduce the max stack allocated buffer by an extra amount to increase
// the chance of hitting it, even when `fun`'s first access is some distance
// into its *further* stack frame, particularly if the call was inlined and
// therefore not writing a frame pointer.
const size_t play = 64 * sizeof(char *); // 512B on 64b archs
boost::container::small_vector<char, stack_protection_size - play> buffer;
buffer.reserve(s.size() * 2 + 2); buffer.reserve(s.size() * 2 + 2);
char * buf = buffer.data(); char * buf = buffer.data();
char * p = buf; char * p = buf;