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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Assertions.h>
#include <AK/Types.h>
#include <fcntl.h>
#include <stdio.h>
#include <sys/mman.h>
#include <unistd.h>
#define EXPECT_OK(syscall, address, size) \
do { \
rc = syscall(fd, (void*)(address), (size_t)(size)); \
if (rc < 0) { \
fprintf(stderr, "Expected success: " #syscall "(%p, %zu), got rc=%d, errno=%d\n", (void*)(address), (size_t)(size), rc, errno); \
} \
} while (0)
#define EXPECT_EFAULT(syscall, address, size) \
do { \
rc = syscall(fd, (void*)(address), (size_t)(size)); \
if (rc >= 0 || errno != EFAULT) { \
fprintf(stderr, "Expected EFAULT: " #syscall "(%p, %zu), got rc=%d, errno=%d\n", (void*)(address), (size_t)(size), rc, errno); \
} \
} while (0)
#define EXPECT_EFAULT_NO_FD(syscall, address, size) \
do { \
rc = syscall((address), (size_t)(size)); \
if (rc >= 0 || errno != EFAULT) { \
fprintf(stderr, "Expected EFAULT: " #syscall "(%p, %zu), got rc=%d, errno=%d\n", (void*)(address), (size_t)(size), rc, errno); \
} \
} while (0)
int main(int, char**)
{
int fd = open("/dev/zero", O_RDONLY);
int rc;
// Test a one-page mapping (4KB)
u8* one_page = (u8*)mmap(nullptr, 4096, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
VERIFY(one_page);
EXPECT_OK(read, one_page, 4096);
EXPECT_EFAULT(read, one_page, 4097);
EXPECT_EFAULT(read, one_page - 1, 4096);
// Test a two-page mapping (8KB)
u8* two_page = (u8*)mmap(nullptr, 8192, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
VERIFY(two_page);
EXPECT_OK(read, two_page, 4096);
EXPECT_OK(read, two_page + 4096, 4096);
EXPECT_OK(read, two_page, 8192);
EXPECT_OK(read, two_page + 4095, 4097);
EXPECT_OK(read, two_page + 1, 8191);
EXPECT_EFAULT(read, two_page, 8193);
EXPECT_EFAULT(read, two_page - 1, 1);
// Check validation of pages between the first and last address.
ptrdiff_t distance = two_page - one_page;
EXPECT_EFAULT(read, one_page, (u32)distance + 1024);
// Test every kernel page just because.
for (u64 kernel_address = 0xc0000000; kernel_address <= 0xffffffff; kernel_address += PAGE_SIZE) {
EXPECT_EFAULT(read, (void*)kernel_address, 1);
}
// Test the page just below where the kernel VM begins.
u8* jerk_page = (u8*)mmap((void*)(0xc0000000 - PAGE_SIZE), PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, 0, 0);
VERIFY(jerk_page == (void*)(0xc0000000 - PAGE_SIZE));
EXPECT_OK(read, jerk_page, 4096);
EXPECT_EFAULT(read, jerk_page, 4097);
// Test something that would wrap around the 2^32 mark.
EXPECT_EFAULT(read, jerk_page, 0x50000000);
return 0;
}
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