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TmpFS: Reads past the end of a file should be zero-length

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This commit is contained in:
Andreas Kling 2020-01-08 12:45:39 +01:00
parent 50056d1d84
commit 28ee5b0e98
2 changed files with 23 additions and 0 deletions
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3
Kernel/FileSystem/TmpFS.cpp
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@ -160,6 +160,9 @@ ssize_t TmpFSInode::read_bytes(off_t offset, ssize_t size, u8* buffer, FileDescr
if (!m_content.has_value())
return 0;
if (offset >= m_metadata.size)
return 0;
if (static_cast<off_t>(size) > m_metadata.size - offset)
size = m_metadata.size - offset;

20
Userland/test_io.cpp
View file

@ -121,6 +121,25 @@ void test_mmap_directory()
close(fd);
}
void test_tmpfs_read_past_end()
{
int fd = open("/tmp/x", O_RDWR | O_CREAT | O_TRUNC, 0600);
ASSERT(fd >= 0);
int rc = ftruncate(fd, 1);
ASSERT(rc == 0);
rc = lseek(fd, 4096, SEEK_SET);
ASSERT(rc == 4096);
char buffer[16];
int nread = read(fd, buffer, sizeof(buffer));
if (nread != 0) {
fprintf(stderr, "Expected 0-length read past end of file in /tmp\n");
}
close(fd);
}
int main(int, char**)
{
int rc;
@ -140,6 +159,7 @@ int main(int, char**)
test_ftruncate_readonly();
test_ftruncate_negative();
test_mmap_directory();
test_tmpfs_read_past_end();
return 0;
}