ladybird/AK/MappedFile.cpp
Andreas Kling c110cf193d Kernel: Have the open() syscall take an explicit path length parameter.
Instead of computing the path length inside the syscall handler, let the
caller do that work. This allows us to implement to new variants of open()
and creat(), called open_with_path_length() and creat_with_path_length().
These are suitable for use with e.g StringView.
2019-07-08 20:01:49 +02:00

74 lines
1.5 KiB
C++

#include <AK/AKString.h>
#include <AK/MappedFile.h>
#include <fcntl.h>
#include <stdio.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
//#define DEBUG_MAPPED_FILE
namespace AK {
MappedFile::MappedFile(const StringView& file_name)
{
m_size = PAGE_SIZE;
m_fd = open_with_path_length(file_name.characters_without_null_termination(), file_name.length(), O_RDONLY | O_CLOEXEC, 0);
if (m_fd != -1) {
struct stat st;
fstat(m_fd, &st);
m_size = st.st_size;
m_map = mmap(nullptr, m_size, PROT_READ, MAP_SHARED, m_fd, 0);
if (m_map == MAP_FAILED)
perror("");
}
#ifdef DEBUG_MAPPED_FILE
dbgprintf("MappedFile{%s} := { m_fd=%d, m_size=%u, m_map=%p }\n", file_name.characters(), m_fd, m_size, m_map);
#endif
}
MappedFile::~MappedFile()
{
unmap();
}
void MappedFile::unmap()
{
if (!is_valid())
return;
ASSERT(m_fd != -1);
int rc = munmap(m_map, m_size);
ASSERT(rc == 0);
rc = close(m_fd);
ASSERT(rc == 0);
m_size = 0;
m_fd = -1;
m_map = (void*)-1;
}
MappedFile::MappedFile(MappedFile&& other)
: m_size(other.m_size)
, m_fd(other.m_fd)
, m_map(other.m_map)
{
other.m_size = 0;
other.m_fd = -1;
other.m_map = (void*)-1;
}
MappedFile& MappedFile::operator=(MappedFile&& other)
{
if (this == &other)
return *this;
unmap();
swap(m_size, other.m_size);
swap(m_fd, other.m_fd);
swap(m_map, other.m_map);
return *this;
}
}