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* Simplify communication with the hook a bit (don't use file

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descriptors 3/4, just use stdin/stderr).
This commit is contained in:
Eelco Dolstra 2009-03-28 19:29:55 +00:00
parent 7fb548aa26
commit 3a2bbe7f8a
6 changed files with 68 additions and 117 deletions
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86
src/libstore/build.cc
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@ -660,7 +660,6 @@ private:
/* Pipes for talking to the build hook (if any). */
Pipe toHook;
Pipe fromHook;
/* Whether we're currently doing a chroot build. */
bool useChroot;
@ -1207,49 +1206,6 @@ void DerivationGoal::buildDone()
}
static string readLine(int fd)
{
string s;
while (1) {
checkInterrupt();
char ch;
ssize_t rd = read(fd, &ch, 1);
if (rd == -1) {
if (errno != EINTR)
throw SysError("reading a line");
} else if (rd == 0)
throw Error("unexpected EOF reading a line");
else {
if (ch == '\n') return s;
s += ch;
}
}
}
static void writeLine(int fd, string s)
{
s += '\n';
writeFull(fd, (const unsigned char *) s.c_str(), s.size());
}
/* !!! ugly hack */
static void drain(int fd)
{
unsigned char buffer[1024];
while (1) {
checkInterrupt();
ssize_t rd = read(fd, buffer, sizeof buffer);
if (rd == -1) {
if (errno != EINTR)
throw SysError("draining");
} else if (rd == 0) break;
else writeToStderr(buffer, rd);
}
}
DerivationGoal::HookReply DerivationGoal::tryBuildHook()
{
if (!useBuildHook) return rpDecline;
@ -1266,7 +1222,6 @@ DerivationGoal::HookReply DerivationGoal::tryBuildHook()
/* Create the communication pipes. */
toHook.create();
fromHook.create();
/* Fork the hook. */
pid = fork();
@ -1310,16 +1265,20 @@ DerivationGoal::HookReply DerivationGoal::tryBuildHook()
worker.childStarted(shared_from_this(),
pid, singleton<set<int> >(logPipe.readSide), false);
fromHook.writeSide.close();
toHook.readSide.close();
/* Read the first line of input, which should be a word indicating
whether the hook wishes to perform the build. !!! potential
for deadlock here: we should also read from the child's logger
pipe. */
whether the hook wishes to perform the build. */
string reply;
try {
reply = readLine(fromHook.readSide);
while (true) {
string s = readLine(logPipe.readSide);
if (string(s, 0, 2) == "# ") {
reply = string(s, 2);
break;
}
handleChildOutput(logPipe.readSide, s + "\n");
}
} catch (Error & e) {
terminateBuildHook(true);
throw;
@ -1335,7 +1294,7 @@ DerivationGoal::HookReply DerivationGoal::tryBuildHook()
else if (reply == "accept") {
printMsg(lvlInfo, format("running hook to build path(s) %1%")
printMsg(lvlInfo, format("using hook to build path(s) %1%")
% showPaths(outputPaths(drv.outputs)));
/* Write the information that the hook needs to perform the
@ -1377,13 +1336,13 @@ DerivationGoal::HookReply DerivationGoal::tryBuildHook()
writeStringToFile(referencesFN,
makeValidityRegistration(allInputs, true, false));
/* Tell the hook to proceed. */
/* Tell the hook to proceed. */
writeLine(toHook.writeSide, "okay");
toHook.writeSide.close();
if (printBuildTrace) {
if (printBuildTrace)
printMsg(lvlError, format("@ build-started %1% %2% %3% %4%")
% drvPath % drv.outputs["out"].path % drv.platform % logFile);
}
return rpAccept;
}
@ -1394,7 +1353,6 @@ DerivationGoal::HookReply DerivationGoal::tryBuildHook()
void DerivationGoal::terminateBuildHook(bool kill)
{
/* !!! drain stdout of hook */
debug("terminating build hook");
pid_t savedPid = pid;
if (kill)
@ -1404,10 +1362,8 @@ void DerivationGoal::terminateBuildHook(bool kill)
/* `false' means don't wake up waiting goals, since we want to
keep this build slot ourselves. */
worker.childTerminated(savedPid, false);
fromHook.readSide.close();
toHook.writeSide.close();
fdLogFile.close();
drain(logPipe.readSide);
logPipe.readSide.close();
deleteTmpDir(true); /* get rid of the hook's temporary directory */
}
@ -1993,24 +1949,14 @@ void DerivationGoal::initChild()
throw SysError(format("changing into `%1%'") % tmpDir);
/* When running a hook, dup the communication pipes. */
bool inHook = fromHook.writeSide.isOpen();
if (inHook) {
fromHook.readSide.close();
if (dup2(fromHook.writeSide, 3) == -1)
throw SysError("dupping from-hook write side");
if (usingBuildHook) {
toHook.writeSide.close();
if (dup2(toHook.readSide, 4) == -1)
if (dup2(toHook.readSide, STDIN_FILENO) == -1)
throw SysError("dupping to-hook read side");
}
/* Close all other file descriptors. */
set<int> exceptions;
if (inHook) {
exceptions.insert(3);
exceptions.insert(4);
}
closeMostFDs(exceptions);
closeMostFDs(set<int>());
}