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mirror of https://github.com/rui314/mold.git synced 2024-11-11 16:58:12 +03:00
mold/output_file.cc
2021-01-24 13:22:32 +09:00

99 lines
2.7 KiB
C++

#include "mold.h"
#include <fcntl.h>
#include <libgen.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
static u32 get_umask() {
u32 orig_umask = umask(0);
umask(orig_umask);
return orig_umask;
}
class MemoryMappedOutputFile : public OutputFile {
public:
MemoryMappedOutputFile(std::string path, i64 filesize)
: OutputFile(path, filesize) {
std::string dir = dirname(strdup(config.output.c_str()));
tmpfile = strdup((dir + "/.mold-XXXXXX").c_str());
i64 fd = mkstemp(tmpfile);
if (fd == -1)
Error() << "cannot open " << tmpfile << ": " << strerror(errno);
if (rename(config.output.c_str(), tmpfile) == 0) {
::close(fd);
fd = ::open(tmpfile, O_RDWR | O_CREAT, 0777);
if (fd == -1) {
if (errno != ETXTBSY)
Error() << "cannot open " << config.output << ": " << strerror(errno);
unlink(tmpfile);
fd = ::open(tmpfile, O_RDWR | O_CREAT, 0777);
if (fd == -1)
Error() << "cannot open " << config.output << ": " << strerror(errno);
}
}
if (ftruncate(fd, filesize))
Error() << "ftruncate failed";
if (fchmod(fd, (0777 & ~get_umask())) == -1)
Error() << "fchmod failed";
buf = (u8 *)mmap(nullptr, filesize, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (buf == MAP_FAILED)
Error() << config.output << ": mmap failed: " << strerror(errno);
::close(fd);
}
void close() override {
Timer t("munmap");
munmap(buf, filesize);
if (rename(tmpfile, config.output.c_str()) == -1)
Error() << config.output << ": rename filed: " << strerror(errno);
tmpfile = nullptr;
}
};
class MallocOutputFile : public OutputFile {
public:
MallocOutputFile(std::string path, u64 filesize)
: OutputFile(path, filesize) {
buf = (u8 *)mmap(NULL, filesize, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_ANONYMOUS, -1, 0);
if (buf == MAP_FAILED)
Error() << "mmap failed: " << strerror(errno);
}
void close() override {
Timer t("munmap");
i64 fd = ::open(path.c_str(), O_RDWR | O_CREAT, 0777);
if (fd == -1)
Error() << "cannot open " << config.output << ": " << strerror(errno);
FILE *fp = fdopen(fd, "w");
fwrite(buf, filesize, 1, fp);
fclose(fp);
}
};
OutputFile *OutputFile::open(std::string path, u64 filesize) {
Timer t("open_file");
bool is_special = false;
struct stat st;
if (stat(path.c_str(), &st) == 0 && (st.st_mode & S_IFMT) != S_IFREG)
is_special = true;
OutputFile *file;
if (is_special)
file = new MallocOutputFile(path, filesize);
else
file = new MemoryMappedOutputFile(path, filesize);
if (config.filler != -1)
memset(file->buf, config.filler, filesize);
return file;
}