Nix/src/libutil/posix-source-accessor.cc

93 lines
2.6 KiB
C++

#include "posix-source-accessor.hh"
#include "signals.hh"
namespace nix {
void PosixSourceAccessor::readFile(
const CanonPath & path,
Sink & sink,
std::function<void(uint64_t)> sizeCallback)
{
// FIXME: add O_NOFOLLOW since symlinks should be resolved by the
// caller?
AutoCloseFD fd = open(path.c_str(), O_RDONLY | O_CLOEXEC);
if (!fd)
throw SysError("opening file '%1%'", path);
struct stat st;
if (fstat(fd.get(), &st) == -1)
throw SysError("statting file");
sizeCallback(st.st_size);
off_t left = st.st_size;
std::vector<unsigned char> buf(64 * 1024);
while (left) {
checkInterrupt();
ssize_t rd = read(fd.get(), buf.data(), (size_t) std::min(left, (off_t) buf.size()));
if (rd == -1) {
if (errno != EINTR)
throw SysError("reading from file '%s'", showPath(path));
}
else if (rd == 0)
throw SysError("unexpected end-of-file reading '%s'", showPath(path));
else {
assert(rd <= left);
sink({(char *) buf.data(), (size_t) rd});
left -= rd;
}
}
}
bool PosixSourceAccessor::pathExists(const CanonPath & path)
{
return nix::pathExists(path.abs());
}
std::optional<SourceAccessor::Stat> PosixSourceAccessor::maybeLstat(const CanonPath & path)
{
struct stat st;
if (::lstat(path.c_str(), &st)) {
if (errno == ENOENT) return std::nullopt;
throw SysError("getting status of '%s'", showPath(path));
}
mtime = std::max(mtime, st.st_mtime);
return Stat {
.type =
S_ISREG(st.st_mode) ? tRegular :
S_ISDIR(st.st_mode) ? tDirectory :
S_ISLNK(st.st_mode) ? tSymlink :
tMisc,
.fileSize = S_ISREG(st.st_mode) ? std::optional<uint64_t>(st.st_size) : std::nullopt,
.isExecutable = S_ISREG(st.st_mode) && st.st_mode & S_IXUSR,
};
}
SourceAccessor::DirEntries PosixSourceAccessor::readDirectory(const CanonPath & path)
{
DirEntries res;
for (auto & entry : nix::readDirectory(path.abs())) {
std::optional<Type> type;
switch (entry.type) {
case DT_REG: type = Type::tRegular; break;
case DT_LNK: type = Type::tSymlink; break;
case DT_DIR: type = Type::tDirectory; break;
}
res.emplace(entry.name, type);
}
return res;
}
std::string PosixSourceAccessor::readLink(const CanonPath & path)
{
return nix::readLink(path.abs());
}
std::optional<CanonPath> PosixSourceAccessor::getPhysicalPath(const CanonPath & path)
{
return path;
}
}