154 lines
4.0 KiB
C++
154 lines
4.0 KiB
C++
#include <fcntl.h>
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#include "config.hh"
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#include "fs-sink.hh"
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namespace nix {
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void copyRecursive(
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SourceAccessor & accessor, const CanonPath & from,
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FileSystemObjectSink & sink, const Path & to)
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{
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auto stat = accessor.lstat(from);
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switch (stat.type) {
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case SourceAccessor::tSymlink:
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{
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sink.createSymlink(to, accessor.readLink(from));
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}
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case SourceAccessor::tRegular:
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{
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sink.createRegularFile(to, [&](CreateRegularFileSink & crf) {
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if (stat.isExecutable)
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crf.isExecutable();
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accessor.readFile(from, crf, [&](uint64_t size) {
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crf.preallocateContents(size);
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});
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});
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break;
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}
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case SourceAccessor::tDirectory:
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{
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sink.createDirectory(to);
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for (auto & [name, _] : accessor.readDirectory(from)) {
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copyRecursive(
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accessor, from / name,
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sink, to + "/" + name);
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break;
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}
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}
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case SourceAccessor::tMisc:
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throw Error("file '%1%' has an unsupported type", from);
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default:
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abort();
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}
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}
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struct RestoreSinkSettings : Config
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{
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Setting<bool> preallocateContents{this, false, "preallocate-contents",
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"Whether to preallocate files when writing objects with known size."};
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};
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static RestoreSinkSettings restoreSinkSettings;
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static GlobalConfig::Register r1(&restoreSinkSettings);
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void RestoreSink::createDirectory(const Path & path)
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{
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Path p = dstPath + path;
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if (mkdir(p.c_str(), 0777) == -1)
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throw SysError("creating directory '%1%'", p);
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};
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struct RestoreRegularFile : CreateRegularFileSink {
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AutoCloseFD fd;
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void operator () (std::string_view data) override;
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void isExecutable() override;
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void preallocateContents(uint64_t size) override;
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};
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void RestoreSink::createRegularFile(const Path & path, std::function<void(CreateRegularFileSink &)> func)
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{
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Path p = dstPath + path;
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RestoreRegularFile crf;
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crf.fd = open(p.c_str(), O_CREAT | O_EXCL | O_WRONLY | O_CLOEXEC, 0666);
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if (!crf.fd) throw SysError("creating file '%1%'", p);
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func(crf);
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}
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void RestoreRegularFile::isExecutable()
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{
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struct stat st;
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if (fstat(fd.get(), &st) == -1)
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throw SysError("fstat");
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if (fchmod(fd.get(), st.st_mode | (S_IXUSR | S_IXGRP | S_IXOTH)) == -1)
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throw SysError("fchmod");
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}
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void RestoreRegularFile::preallocateContents(uint64_t len)
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{
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if (!restoreSinkSettings.preallocateContents)
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return;
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#if HAVE_POSIX_FALLOCATE
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if (len) {
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errno = posix_fallocate(fd.get(), 0, len);
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/* Note that EINVAL may indicate that the underlying
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filesystem doesn't support preallocation (e.g. on
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OpenSolaris). Since preallocation is just an
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optimisation, ignore it. */
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if (errno && errno != EINVAL && errno != EOPNOTSUPP && errno != ENOSYS)
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throw SysError("preallocating file of %1% bytes", len);
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}
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#endif
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}
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void RestoreRegularFile::operator () (std::string_view data)
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{
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writeFull(fd.get(), data);
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}
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void RestoreSink::createSymlink(const Path & path, const std::string & target)
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{
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Path p = dstPath + path;
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nix::createSymlink(target, p);
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}
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void RegularFileSink::createRegularFile(const Path & path, std::function<void(CreateRegularFileSink &)> func)
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{
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struct CRF : CreateRegularFileSink {
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RegularFileSink & back;
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CRF(RegularFileSink & back) : back(back) {}
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void operator () (std::string_view data) override
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{
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back.sink(data);
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}
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void isExecutable() override {}
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} crf { *this };
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func(crf);
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}
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void NullFileSystemObjectSink::createRegularFile(const Path & path, std::function<void(CreateRegularFileSink &)> func)
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{
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struct : CreateRegularFileSink {
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void operator () (std::string_view data) override {}
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void isExecutable() override {}
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} crf;
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// Even though `NullFileSystemObjectSink` doesn't do anything, it's important
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// that we call the function, to e.g. advance the parser using this
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// sink.
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func(crf);
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}
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}
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