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[libc] add mremap (#112804)

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This commit is contained in:
Jingyu Qiu
2024-11-06 13:25:50 -05:00
committed by GitHub
parent 38cc03f78e
commit 5a6cc50921
10 changed files with 194 additions and 1 deletions
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1
libc/config/linux/aarch64/entrypoints.txt
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@@ -245,6 +245,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.sys.mman.mlock2
libc.src.sys.mman.mlockall
libc.src.sys.mman.mmap
libc.src.sys.mman.mremap
libc.src.sys.mman.mprotect
libc.src.sys.mman.msync
libc.src.sys.mman.munlock

1
libc/config/linux/x86_64/entrypoints.txt
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@@ -244,6 +244,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.sys.mman.mlock2
libc.src.sys.mman.mlockall
libc.src.sys.mman.mmap
libc.src.sys.mman.mremap
libc.src.sys.mman.mprotect
libc.src.sys.mman.msync
libc.src.sys.mman.munlock

10
libc/newhdrgen/yaml/sys/mman.yaml
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@@ -55,6 +55,16 @@ functions:
- type: int
- type: int
- type: off_t
- name: mremap
standards:
- POSIX
return_type: void *
arguments:
- type: void *
- type: size_t
- type: size_t
- type: int
- type: '...'
- name: mprotect
standards:
- POSIX

13
libc/spec/linux.td
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@@ -103,7 +103,7 @@ def Linux : StandardSpec<"Linux"> {
ArgSpec<UnsignedIntType>,
]
>,
FunctionSpec<
FunctionSpec<
"remap_file_pages",
RetValSpec<IntType>,
[
@@ -114,6 +114,17 @@ def Linux : StandardSpec<"Linux"> {
ArgSpec<IntType>,
]
>,
FunctionSpec<
"mremap",
RetValSpec<VoidPtr>,
[
ArgSpec<VoidPtr>,
ArgSpec<SizeTType>,
ArgSpec<SizeTType>,
ArgSpec<IntType>,
ArgSpec<VarArgType>,
]
>,
] // Functions
>;

7
libc/src/sys/mman/CMakeLists.txt
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@@ -106,3 +106,10 @@ add_entrypoint_object(
DEPENDS
.${LIBC_TARGET_OS}.shm_unlink
)
add_entrypoint_object(
mremap
ALIAS
DEPENDS
.${LIBC_TARGET_OS}.mremap
)

13
libc/src/sys/mman/linux/CMakeLists.txt
View File

@@ -24,6 +24,19 @@ add_entrypoint_object(
libc.src.errno.errno
)
add_entrypoint_object(
mremap
SRCS
mremap.cpp
HDRS
../mremap.h
DEPENDS
libc.include.sys_mman
libc.include.sys_syscall
libc.src.__support.OSUtil.osutil
libc.src.errno.errno
)
add_entrypoint_object(
munmap
SRCS

45
libc/src/sys/mman/linux/mremap.cpp Normal file
View File

@@ -0,0 +1,45 @@
//===---------- Linux implementation of the POSIX mremap function----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "src/sys/mman/mremap.h"
#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
#include "src/__support/common.h"
#include "src/__support/macros/config.h"
#include "src/errno/libc_errno.h"
#include <linux/param.h> // For EXEC_PAGESIZE.
#include <stdarg.h>
#include <sys/syscall.h> // For syscall numbers.
namespace LIBC_NAMESPACE_DECL {
LLVM_LIBC_FUNCTION(void *, mremap,
(void *old_address, size_t old_size, size_t new_size,
int flags, ... /* void *new_address */)) {
long ret = 0;
void *new_address = nullptr;
if (flags & MREMAP_FIXED) {
va_list varargs;
va_start(varargs, flags);
new_address = va_arg(varargs, void *);
va_end(varargs);
}
ret = LIBC_NAMESPACE::syscall_impl<long>(SYS_mremap, old_address, old_size,
new_size, flags, new_address);
if (ret < 0 && ret > -EXEC_PAGESIZE) {
libc_errno = static_cast<int>(-ret);
return MAP_FAILED;
}
return reinterpret_cast<void *>(ret);
}
} // namespace LIBC_NAMESPACE_DECL

22
libc/src/sys/mman/mremap.h Normal file
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@@ -0,0 +1,22 @@
//===-- Implementation header for mremap function -------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC_SYS_MMAN_MREMAP_H
#define LLVM_LIBC_SRC_SYS_MMAN_MREMAP_H
#include "src/__support/macros/config.h"
#include <sys/mman.h> // For size_t and off_t
namespace LIBC_NAMESPACE_DECL {
void *mremap(void *old_address, size_t old_size, size_t new_size, int flags,
... /* void *new_address */);
} // namespace LIBC_NAMESPACE_DECL
#endif // LLVM_LIBC_SRC_SYS_MMAN_MREMAP_H

15
libc/test/src/sys/mman/linux/CMakeLists.txt
View File

@@ -14,6 +14,21 @@ add_libc_unittest(
libc.test.UnitTest.ErrnoSetterMatcher
)
add_libc_unittest(
mremap_test
SUITE
libc_sys_mman_unittests
SRCS
mremap_test.cpp
DEPENDS
libc.include.sys_mman
libc.src.errno.errno
libc.src.sys.mman.mmap
libc.src.sys.mman.mremap
libc.src.sys.mman.munmap
libc.test.UnitTest.ErrnoSetterMatcher
)
if (NOT LLVM_USE_SANITIZER)
add_libc_unittest(
mprotect_test

68
libc/test/src/sys/mman/linux/mremap_test.cpp Normal file
View File

@@ -0,0 +1,68 @@
//===-- Unittests for mremap ----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "src/errno/libc_errno.h"
#include "src/sys/mman/mmap.h"
#include "src/sys/mman/mremap.h"
#include "src/sys/mman/munmap.h"
#include "test/UnitTest/ErrnoSetterMatcher.h"
#include "test/UnitTest/Test.h"
#include <sys/mman.h>
using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
TEST(LlvmLibcMremapTest, NoError) {
size_t initial_size = 128;
size_t new_size = 256;
LIBC_NAMESPACE::libc_errno = 0;
// Allocate memory using mmap.
void *addr =
LIBC_NAMESPACE::mmap(nullptr, initial_size, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
ASSERT_ERRNO_SUCCESS();
EXPECT_NE(addr, MAP_FAILED);
int *array = reinterpret_cast<int *>(addr);
// Writing to the memory should not crash the test.
array[0] = 123;
EXPECT_EQ(array[0], 123);
// Re-map the memory using mremap with an increased size.
void *new_addr =
LIBC_NAMESPACE::mremap(addr, initial_size, new_size, MREMAP_MAYMOVE);
ASSERT_ERRNO_SUCCESS();
EXPECT_NE(new_addr, MAP_FAILED);
EXPECT_EQ(reinterpret_cast<int *>(new_addr)[0],
123); // Verify data is preserved.
// Clean up memory by unmapping it.
EXPECT_THAT(LIBC_NAMESPACE::munmap(new_addr, new_size), Succeeds());
}
TEST(LlvmLibcMremapTest, Error_InvalidSize) {
size_t initial_size = 128;
LIBC_NAMESPACE::libc_errno = 0;
// Allocate memory using mmap.
void *addr =
LIBC_NAMESPACE::mmap(nullptr, initial_size, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
ASSERT_ERRNO_SUCCESS();
EXPECT_NE(addr, MAP_FAILED);
// Attempt to re-map the memory with an invalid new size (0).
void *new_addr =
LIBC_NAMESPACE::mremap(addr, initial_size, 0, MREMAP_MAYMOVE);
EXPECT_THAT(new_addr, Fails(EINVAL, MAP_FAILED));
// Clean up the original mapping.
EXPECT_THAT(LIBC_NAMESPACE::munmap(addr, initial_size), Succeeds());
}