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libc: Introduce calls to sysconf to get page size. #163462

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Merged
merged 3 commits into from
Oct 15, 2025
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libc: Introduce calls to sysconf to get page size. #163462

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[𝘀𝗽𝗿] initial version
pcc Oct 14, 2025
4e70bf8
Address review comments
pcc Oct 15, 2025
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Update bazel files
pcc Oct 15, 2025
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5 changes: 3 additions & 2 deletions libc/test/src/sys/mman/linux/mincore_test.cpp
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Expand Up @@ -16,12 +16,13 @@
#include "test/UnitTest/ErrnoSetterMatcher.h"
#include "test/UnitTest/Test.h"

#include <unistd.h>
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@michaelrj-google michaelrj-google Oct 14, 2025

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this should be the LLVM-libc sysconf.

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#include <unistd.h>
#include "src/unistd/sysconf.h"

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@pcc pcc Oct 14, 2025

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Done


using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
using LlvmLibcMincoreTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;

// TODO: Replace with sysconf call once the function is properly implemented.
constexpr size_t PAGE_SIZE = 4096;
const size_t PAGE_SIZE = sysconf(_SC_PAGESIZE);
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@michaelrj-google michaelrj-google Oct 14, 2025

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you need to call the sysconf in the LLVM-libc namespace.

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const size_t PAGE_SIZE = sysconf(_SC_PAGESIZE);
const size_t PAGE_SIZE = LIBC_NAMESPACE::sysconf(_SC_PAGESIZE);

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@jhuber6 jhuber6 Oct 14, 2025

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It's fine for tests, but just be aware that this changes the behavior to require a global constructor.

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@pcc pcc Oct 14, 2025

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Right, I also figured that would be fine for tests

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@pcc pcc Oct 14, 2025

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Done


TEST_F(LlvmLibcMincoreTest, UnMappedMemory) {
unsigned char vec;
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4 changes: 2 additions & 2 deletions libc/test/src/sys/mman/linux/mlock_test.cpp
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Expand Up @@ -27,9 +27,9 @@
#include "test/UnitTest/Test.h"

#include <sys/syscall.h>
#include <unistd.h>

// TODO: Replace with sysconf call once the function is properly implemented.
constexpr size_t PAGE_SIZE = 4096;
const size_t PAGE_SIZE = sysconf(_SC_PAGESIZE);

using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
using LlvmLibcMlockTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
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5 changes: 3 additions & 2 deletions libc/test/src/sys/mman/linux/msync_test.cpp
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Expand Up @@ -15,8 +15,9 @@
#include "test/UnitTest/ErrnoSetterMatcher.h"
#include "test/UnitTest/Test.h"

// TODO: Replace with sysconf call once the function is properly implemented.
constexpr size_t PAGE_SIZE = 4096;
#include <unistd.h>

const size_t PAGE_SIZE = sysconf(_SC_PAGESIZE);

using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
using LlvmLibcMsyncTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
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4 changes: 2 additions & 2 deletions libc/test/src/sys/mman/linux/remap_file_pages_test.cpp
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Expand Up @@ -17,9 +17,9 @@

#include <sys/mman.h>
#include <sys/stat.h> // For S_IRWXU
#include <unistd.h>

// TODO: Replace with sysconf call once the function is properly implemented.
constexpr size_t PAGE_SIZE = 4096;
const size_t PAGE_SIZE = sysconf(_SC_PAGESIZE);

using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
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