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https://github.com/RGBCube/serenity
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ca254699ec
So far we only had mmap(2) functionality on the /dev/mem device, but now we can also do read(2) on it. The test unit was updated to check we are doing it safely.
105 lines
3 KiB
C++
105 lines
3 KiB
C++
/*
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* Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Types.h>
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#include <LibTest/TestCase.h>
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#include <assert.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <inttypes.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <unistd.h>
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static u8 read_buffer[0x100000];
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static ALWAYS_INLINE bool mem_chunk(int fd, u64 base, u64 length)
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{
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u64 mmoffset = base % sysconf(_SC_PAGESIZE);
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void* mmp = mmap(NULL, mmoffset + length, PROT_READ, MAP_SHARED, fd, base - mmoffset);
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return mmp != MAP_FAILED;
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}
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enum class ReadResult {
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SeekFailure,
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ReadFailure,
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ReadSuccess,
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};
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static ALWAYS_INLINE ReadResult read_chunk(int fd, u64 base, u64 length)
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{
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VERIFY(length <= sizeof(read_buffer));
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auto rs = lseek(fd, base, SEEK_SET);
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if (rs < 0) {
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fprintf(stderr, "Couldn't seek to offset %" PRIi64 " while verifying: %s\n", base, strerror(errno));
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return ReadResult::SeekFailure;
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}
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if (read(fd, read_buffer, length) < 0)
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return ReadResult::ReadFailure;
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return ReadResult::ReadSuccess;
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}
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TEST_CASE(test_memory_access_device_read)
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{
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int rc = geteuid();
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EXPECT_EQ(rc, 0);
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int fd = open("/dev/mem", O_RDONLY);
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EXPECT(fd >= 0);
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// FIXME: This is expected to work on QEMU machines (both 440FX and Q35),
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// however, it will be much nicer to have some sort of a node in the ProcFS
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// to expose physical memory ranges (e820 memory map).
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auto read_result = read_chunk(fd, 0x0, 0x100000);
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EXPECT_EQ(read_result, ReadResult::ReadFailure);
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read_result = read_chunk(fd, 0xe0000, 0x100000 - 0xe0000);
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EXPECT_EQ(read_result, ReadResult::ReadSuccess);
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read_result = read_chunk(fd, 0x100000, 0x200000 - 0x100000);
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EXPECT_EQ(read_result, ReadResult::ReadFailure);
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read_result = read_chunk(fd, 0xf0000, 70000);
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EXPECT_EQ(read_result, ReadResult::ReadFailure);
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read_result = read_chunk(fd, 0xfffc0000, 16384);
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EXPECT_EQ(read_result, ReadResult::ReadSuccess);
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read_result = read_chunk(fd, 0xfffc0000, 0x100000);
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EXPECT_EQ(read_result, ReadResult::ReadFailure);
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}
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TEST_CASE(test_memory_access_device_mmap)
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{
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int rc = geteuid();
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EXPECT_EQ(rc, 0);
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int fd = open("/dev/mem", O_RDONLY);
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EXPECT(fd >= 0);
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// FIXME: This is expected to work on QEMU machines (both 440FX and Q35),
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// however, it will be much nicer to have some sort of a node in the ProcFS
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// to expose physical memory ranges (e820 memory map).
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auto mmap_result = mem_chunk(fd, 0xe0000, 0x100000 - 0xe0000);
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EXPECT_EQ(mmap_result, true);
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mmap_result = mem_chunk(fd, 0x100000, 0x200000 - 0x100000);
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EXPECT_EQ(mmap_result, false);
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mmap_result = mem_chunk(fd, 0xf0000, 70000);
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EXPECT_EQ(mmap_result, false);
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mmap_result = mem_chunk(fd, 0xfffc0000, 16384);
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EXPECT_EQ(mmap_result, true);
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mmap_result = mem_chunk(fd, 0xfffc0000, 0x100000);
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EXPECT_EQ(mmap_result, false);
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}
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