diff options
Diffstat (limited to 'src')
-rw-r--r-- | src/nix-worker/main.cc | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/src/nix-worker/main.cc b/src/nix-worker/main.cc index 17e892c648fc..c4a2d8a7a026 100644 --- a/src/nix-worker/main.cc +++ b/src/nix-worker/main.cc @@ -6,6 +6,9 @@ #include "archive.hh" #include <iostream> +#include <unistd.h> +#include <signal.h> +#include <fcntl.h> using namespace nix; @@ -31,6 +34,10 @@ static Sink * _to; /* !!! should make writeToStderr an object */ bool canSendStderr; +/* This function is called anytime we want to write something to + stderr. If we're in a state where the protocol allows it (i.e., + when canSendStderr), send the message to the client over the + socket. */ static void tunnelStderr(const unsigned char * buf, size_t count) { writeFull(STDERR_FILENO, buf, count); @@ -48,11 +55,28 @@ static void tunnelStderr(const unsigned char * buf, size_t count) } +/* A SIGIO signal is received when data is available on the client + communication scoket, or when the client has closed its side of the + socket. This handler is enabled at precisely those moments in the + protocol when we're doing work and the client is supposed to be + quiet. Thus, if we get a SIGIO signal, it means that the client + has quit. So we should quit as well. */ +static void sigioHandler(int sigNo) +{ + _isInterrupted = 1; + canSendStderr = false; + write(STDERR_FILENO, "SIGIO\n", 6); +} + + /* startWork() means that we're starting an operation for which we want to send out stderr to the client. */ static void startWork() { canSendStderr = true; + + /* Handle client death asynchronously. */ + signal(SIGIO, sigioHandler); } @@ -60,6 +84,11 @@ static void startWork() client. */ static void stopWork() { + /* Stop handling async client death; we're going to a state where + we're either sending or receiving from the client, so we'll be + notified of client death anyway. */ + signal(SIGIO, SIG_IGN); + canSendStderr = false; writeInt(STDERR_LAST, *_to); } @@ -178,7 +207,7 @@ static void processConnection(Source & from, Sink & to) writeInt(WORKER_MAGIC_2, to); debug("greeting exchanged"); - + _to = &to; canSendStderr = false; writeToStderr = tunnelStderr; @@ -216,6 +245,13 @@ void run(Strings args) if (arg == "--daemon") daemon = true; } + /* Allow us to receive SIGIO for events on the client socket. */ + signal(SIGIO, SIG_IGN); + if (fcntl(STDIN_FILENO, F_SETOWN, getpid()) == -1) + throw SysError("F_SETOWN"); + if (fcntl(STDIN_FILENO, F_SETFL, fcntl(STDIN_FILENO, F_GETFL, 0) | FASYNC) == -1) + throw SysError("F_SETFL"); + if (slave) { FdSource source(STDIN_FILENO); FdSink sink(STDOUT_FILENO); |