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https://github.com/SerenityOS/serenity
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ebaa9f9d35
Adds the following tests: * if there are multiple shared mmaps for the same file, writes to one mmap region should be visible in the other mmap regions. * if you write to a file with write(), those changes should be visible in shared mmaps for that file. * if you write to a shared mmap, those changes should be visible when you read() from the file. * if you write to a private mmap, any changes you make should not be visible when you read() the file.
93 lines
2.7 KiB
C++
93 lines
2.7 KiB
C++
/*
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* Copyright (c) 2022, 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 <LibTest/TestCase.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <signal.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 <unistd.h>
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static u8* first_mmap = nullptr;
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static u8* second_mmap = nullptr;
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size_t const buf_len = 0x1000;
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static void shared_non_empty_inode_vmobject_sync_signal_handler(int)
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{
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auto rc = msync(first_mmap, buf_len, MS_ASYNC);
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EXPECT(rc == 0);
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rc = munmap(first_mmap, buf_len);
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EXPECT(rc == 0);
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rc = msync(second_mmap, buf_len, MS_ASYNC);
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EXPECT(rc == 0);
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rc = munmap(second_mmap, buf_len);
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EXPECT(rc == 0);
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exit(0);
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}
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TEST_CASE(shared_non_empty_inode_vmobject_sync)
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{
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{
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struct sigaction new_action {
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{ shared_non_empty_inode_vmobject_sync_signal_handler }, 0, 0
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};
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int rc = sigaction(SIGBUS, &new_action, nullptr);
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VERIFY(rc == 0);
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}
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size_t mmap_len = buf_len * 2;
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u8 buf[buf_len];
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memset(buf, 0, sizeof(buf));
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int fd = open("/tmp/shared_non_empty_msync_test", O_RDWR | O_CREAT, 0644);
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VERIFY(fd >= 0);
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auto rc = write(fd, buf, sizeof(buf));
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VERIFY(rc == sizeof(buf));
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first_mmap = (u8*)mmap(nullptr, mmap_len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
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EXPECT(first_mmap != MAP_FAILED);
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second_mmap = (u8*)mmap(nullptr, mmap_len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
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EXPECT(second_mmap != MAP_FAILED);
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// test that changes to one shared mmap are visible in the other shared mmap
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u8 new_val = first_mmap[0] + 1;
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first_mmap[0] = new_val;
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EXPECT(second_mmap[0] == new_val);
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new_val = second_mmap[1] + 1;
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second_mmap[1] = new_val;
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EXPECT(first_mmap[1] == new_val);
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// test that changes in the shared mmap are visible to read()
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new_val = first_mmap[0] + 1;
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first_mmap[0] = new_val;
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rc = msync(first_mmap, mmap_len, MS_SYNC);
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VERIFY(rc == 0);
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rc = lseek(fd, 0, SEEK_SET);
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VERIFY(rc == 0);
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u8 read_byte = 0;
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rc = read(fd, &read_byte, 1);
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VERIFY(rc == 1);
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EXPECT(read_byte == new_val);
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// test that changes made by write() are visible in shared mmaps
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rc = lseek(fd, 0, SEEK_SET);
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VERIFY(rc == 0);
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new_val = first_mmap[0] + 1;
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rc = write(fd, &new_val, 1);
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VERIFY(rc == 1);
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EXPECT(first_mmap[0] == new_val && second_mmap[0] == new_val);
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// test that writes between the file length (buf_len) and mmap_len cause a SIGBUS
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rc = msync(first_mmap, mmap_len, MS_ASYNC);
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EXPECT(rc == 0);
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rc = msync(second_mmap, mmap_len, MS_ASYNC);
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EXPECT(rc == 0);
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first_mmap[buf_len + 1] = 0x1;
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VERIFY_NOT_REACHED();
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}
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