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nix/src/libutil/unix-domain-socket.cc
Graham Christensen e4f62e4608 Apply clang-format universally.
* It is tough to contribute to a project that doesn't use a formatter,
* It is extra hard to contribute to a project which has configured the formatter, but ignores it for some files
* Code formatting makes it harder to hide obscure / weird bugs by accident or on purpose,

Let's rip the bandaid off?

Note that PRs currently in flight should be able to be merged relatively easily by applying `clang-format` to their tip prior to merge.
2025-07-18 12:47:27 -04:00

123 lines
3.7 KiB
C++

#include "nix/util/file-system.hh"
#include "nix/util/unix-domain-socket.hh"
#include "nix/util/util.hh"
#ifdef _WIN32
# include <winsock2.h>
# include <afunix.h>
#else
# include <sys/socket.h>
# include <sys/un.h>
# include "nix/util/processes.hh"
#endif
#include <unistd.h>
namespace nix {
AutoCloseFD createUnixDomainSocket()
{
AutoCloseFD fdSocket = toDescriptor(socket(
PF_UNIX,
SOCK_STREAM
#ifdef SOCK_CLOEXEC
| SOCK_CLOEXEC
#endif
,
0));
if (!fdSocket)
throw SysError("cannot create Unix domain socket");
#ifndef _WIN32
unix::closeOnExec(fdSocket.get());
#endif
return fdSocket;
}
AutoCloseFD createUnixDomainSocket(const Path & path, mode_t mode)
{
auto fdSocket = nix::createUnixDomainSocket();
bind(fdSocket.get(), path);
if (chmod(path.c_str(), mode) == -1)
throw SysError("changing permissions on '%1%'", path);
if (listen(toSocket(fdSocket.get()), 100) == -1)
throw SysError("cannot listen on socket '%1%'", path);
return fdSocket;
}
static void
bindConnectProcHelper(std::string_view operationName, auto && operation, Socket fd, const std::string & path)
{
struct sockaddr_un addr;
addr.sun_family = AF_UNIX;
// Casting between types like these legacy C library interfaces
// require is forbidden in C++. To maintain backwards
// compatibility, the implementation of the bind/connect functions
// contains some hints to the compiler that allow for this
// special case.
auto * psaddr = reinterpret_cast<struct sockaddr *>(&addr);
if (path.size() + 1 >= sizeof(addr.sun_path)) {
#ifdef _WIN32
throw Error("cannot %s to socket at '%s': path is too long", operationName, path);
#else
Pipe pipe;
pipe.create();
Pid pid = startProcess([&] {
try {
pipe.readSide.close();
Path dir = dirOf(path);
if (chdir(dir.c_str()) == -1)
throw SysError("chdir to '%s' failed", dir);
std::string base(baseNameOf(path));
if (base.size() + 1 >= sizeof(addr.sun_path))
throw Error("socket path '%s' is too long", base);
memcpy(addr.sun_path, base.c_str(), base.size() + 1);
if (operation(fd, psaddr, sizeof(addr)) == -1)
throw SysError("cannot %s to socket at '%s'", operationName, path);
writeFull(pipe.writeSide.get(), "0\n");
} catch (SysError & e) {
writeFull(pipe.writeSide.get(), fmt("%d\n", e.errNo));
} catch (...) {
writeFull(pipe.writeSide.get(), "-1\n");
}
});
pipe.writeSide.close();
auto errNo = string2Int<int>(chomp(drainFD(pipe.readSide.get())));
if (!errNo || *errNo == -1)
throw Error("cannot %s to socket at '%s'", operationName, path);
else if (*errNo > 0) {
errno = *errNo;
throw SysError("cannot %s to socket at '%s'", operationName, path);
}
#endif
} else {
memcpy(addr.sun_path, path.c_str(), path.size() + 1);
if (operation(fd, psaddr, sizeof(addr)) == -1)
throw SysError("cannot %s to socket at '%s'", operationName, path);
}
}
void bind(Socket fd, const std::string & path)
{
unlink(path.c_str());
bindConnectProcHelper("bind", ::bind, fd, path);
}
void connect(Socket fd, const std::filesystem::path & path)
{
bindConnectProcHelper("connect", ::connect, fd, path.string());
}
AutoCloseFD connect(const std::filesystem::path & path)
{
auto fd = createUnixDomainSocket();
nix::connect(toSocket(fd.get()), path);
return fd;
}
} // namespace nix