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Merge pull request #8544 from edolstra/handle-missing-gc-socket

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LocalStore: :addTempRoot(): Handle ENOENT
(cherry picked from commit 7115edc85a)
Change-Id: Ie6b1596049c3fde09b98f2f0727899f98e48e6b1
This commit is contained in:
eldritch horrors 2024-03-07 06:15:32 +01:00
parent b14f88e0d4
commit 06e92450bd
3 changed files with 59 additions and 24 deletions
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22
src/libstore/gc.cc
View file

@ -142,11 +142,12 @@ void LocalStore::addTempRoot(const StorePath & path)
try {
nix::connect(fdRootsSocket->get(), socketPath);
} catch (SysError & e) {
/* The garbage collector may have exited, so we need to
restart. */
if (e.errNo == ECONNREFUSED) {
debug("GC socket connection refused");
/* The garbage collector may have exited or not
created the socket yet, so we need to restart. */
if (e.errNo == ECONNREFUSED || e.errNo == ENOENT) {
debug("GC socket connection refused: %s", e.msg());
fdRootsSocket->close();
std::this_thread::sleep_for(std::chrono::milliseconds(100));
goto restart;
}
throw;
@ -502,6 +503,11 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
auto fdGCLock = openGCLock();
FdLock gcLock(fdGCLock.get(), ltWrite, true, "waiting for the big garbage collector lock...");
/* Synchronisation point to test ENOENT handling in
addTempRoot(), see tests/gc-non-blocking.sh. */
if (auto p = getEnv("_NIX_TEST_GC_SYNC_1"))
readFile(*p);
/* Start the server for receiving new roots. */
auto socketPath = stateDir.get() + gcSocketPath;
createDirs(dirOf(socketPath));
@ -625,6 +631,10 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
roots.insert(root.first);
}
/* Synchronisation point for testing, see tests/functional/gc-non-blocking.sh. */
if (auto p = getEnv("_NIX_TEST_GC_SYNC_2"))
readFile(*p);
/* Helper function that deletes a path from the store and throws
GCLimitReached if we've deleted enough garbage. */
auto deleteFromStore = [&](std::string_view baseName)
@ -771,10 +781,6 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
}
};
/* Synchronisation point for testing, see tests/functional/gc-concurrent.sh. */
if (auto p = getEnv("_NIX_TEST_GC_SYNC"))
readFile(*p);
/* Either delete all garbage paths, or just the specified
paths (for gcDeleteSpecific). */
if (options.action == GCOptions::gcDeleteSpecific) {

38
src/libutil/util.cc
View file

@ -2042,21 +2042,35 @@ void connect(int fd, const std::string & path)
addr.sun_family = AF_UNIX;
if (path.size() + 1 >= sizeof(addr.sun_path)) {
Pipe pipe;
pipe.create();
Pid pid = startProcess([&]() {
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 (connect(fd, (struct sockaddr *) &addr, sizeof(addr)) == -1)
throw SysError("cannot connect to socket at '%s'", path);
_exit(0);
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 (connect(fd, (struct sockaddr *) &addr, sizeof(addr)) == -1)
throw SysError("cannot connect to socket at '%s'", 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");
}
});
int status = pid.wait();
if (status != 0)
pipe.writeSide.close();
auto errNo = string2Int<int>(chomp(drainFD(pipe.readSide.get())));
if (!errNo || *errNo == -1)
throw Error("cannot connect to socket at '%s'", path);
else if (*errNo > 0) {
errno = *errNo;
throw SysError("cannot connect to socket at '%s'", path);
}
} else {
memcpy(addr.sun_path, path.c_str(), path.size() + 1);
if (connect(fd, (struct sockaddr *) &addr, sizeof(addr)) == -1)

23
tests/functional/gc-non-blocking.sh
View file

@ -6,27 +6,42 @@ needLocalStore "the GC test needs a synchronisation point"
clearStore
fifo=$TEST_ROOT/test.fifo
mkfifo "$fifo"
# This FIFO is read just after the global GC lock has been acquired,
# but before the root server is started.
fifo1=$TEST_ROOT/test2.fifo
mkfifo "$fifo1"
# This FIFO is read just after the roots have been read, but before
# the actual GC starts.
fifo2=$TEST_ROOT/test.fifo
mkfifo "$fifo2"
dummy=$(nix store add-path ./simple.nix)
running=$TEST_ROOT/running
touch $running
(_NIX_TEST_GC_SYNC=$fifo nix-store --gc -vvvvv; rm $running) &
# Start GC.
(_NIX_TEST_GC_SYNC_1=$fifo1 _NIX_TEST_GC_SYNC_2=$fifo2 nix-store --gc -vvvvv; rm $running) &
pid=$!
sleep 2
# Delay the start of the root server to check that the build below
# correctly handles ENOENT when connecting to the root server.
(sleep 1; echo > $fifo1) &
pid2=$!
# Start a build. This should not be blocked by the GC in progress.
outPath=$(nix-build --max-silent-time 60 -o "$TEST_ROOT/result" -E "
with import ./config.nix;
mkDerivation {
name = \"non-blocking\";
buildCommand = \"set -x; test -e $running; mkdir \$out; echo > $fifo\";
buildCommand = \"set -x; test -e $running; mkdir \$out; echo > $fifo2\";
}")
wait $pid
wait $pid2
(! test -e $running)
(! test -e $dummy)