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nix-daemon: add --stdio flag for handling connections over stdin/stdout

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This commit is contained in:
Shea Levy 2016-09-02 13:30:28 -04:00
parent 53b27ddce2
commit 7d4ccd9b17
1 changed files with 75 additions and 1 deletions
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74
src/nix-daemon/nix-daemon.cc
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@ -22,6 +22,7 @@
#include <errno.h>
#include <pwd.h>
#include <grp.h>
#include <fcntl.h>
#if __APPLE__ || __FreeBSD__
#include <sys/ucred.h>
@ -29,6 +30,25 @@
using namespace nix;
#ifndef __linux__
#define SPLICE_F_MOVE 0
static ssize_t splice(int fd_in, loff_t *off_in, int fd_out, loff_t *off_out, size_t len, unsigned int flags)
{
/* We ignore most parameters, we just have them for conformance with the linux syscall */
char buf[8192];
auto read_count = read(fd_in, buf, sizeof(buf));
if (read_count == -1)
return read_count;
auto write_count = decltype<read_count>(0);
while (write_count < read_count) {
auto res = write(fd_out, buf + write_count, read_count - write_count);
if (res == -1)
return res;
write_count += res;
}
return read_count;
}
#endif
static FdSource from(STDIN_FILENO);
static FdSink to(STDOUT_FILENO);
@ -885,6 +905,8 @@ int main(int argc, char * * argv)
return handleExceptions(argv[0], [&]() {
initNix();
auto stdio = false;
parseCmdLine(argc, argv, [&](Strings::iterator & arg, const Strings::iterator & end) {
if (*arg == "--daemon")
; /* ignored for backwards compatibility */
@ -892,10 +914,62 @@ int main(int argc, char * * argv)
showManPage("nix-daemon");
else if (*arg == "--version")
printVersion("nix-daemon");
else if (*arg == "--stdio")
stdio = true;
else return false;
return true;
});
if (stdio) {
if (getStoreType() == tDaemon) {
/* Forward on this connection to the real daemon */
auto socketPath = settings.nixDaemonSocketFile;
auto s = socket(PF_UNIX, SOCK_STREAM, 0);
if (s == -1)
throw SysError("creating Unix domain socket");
auto socketDir = dirOf(socketPath);
if (chdir(socketDir.c_str()) == -1)
throw SysError(format("changing to socket directory %1%") % socketDir);
auto socketName = baseNameOf(socketPath);
auto addr = sockaddr_un{};
addr.sun_family = AF_UNIX;
if (socketName.size() + 1 >= sizeof(addr.sun_path))
throw Error(format("socket name %1% is too long") % socketName);
strcpy(addr.sun_path, socketName.c_str());
if (connect(s, (struct sockaddr *) &addr, sizeof(addr)) == -1)
throw SysError(format("cannot connect to daemon at %1%") % socketPath);
auto nfds = (s > STDIN_FILENO ? s : STDIN_FILENO) + 1;
while (true) {
fd_set fds;
FD_ZERO(&fds);
FD_SET(s, &fds);
FD_SET(STDIN_FILENO, &fds);
if (select(nfds, &fds, nullptr, nullptr, nullptr) == -1)
throw SysError("waiting for data from client or server");
if (FD_ISSET(s, &fds)) {
auto res = splice(s, nullptr, STDOUT_FILENO, nullptr, SIZE_MAX, SPLICE_F_MOVE);
if (res == -1)
throw SysError("splicing data from daemon socket to stdout");
else if (res == 0)
throw EndOfFile("unexpected EOF from daemon socket");
}
if (FD_ISSET(STDIN_FILENO, &fds)) {
auto res = splice(STDIN_FILENO, nullptr, s, nullptr, SIZE_MAX, SPLICE_F_MOVE);
if (res == -1)
throw SysError("splicing data from stdin to daemon socket");
else if (res == 0)
return;
}
}
} else {
processConnection(true);
}
} else {
daemonLoop(argv);
}
});
}