Merge pull request #31393 from azat/fix-stderr-before-reopen

Check stderr is writable before reopining it (to avoid losing errors)
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alexey-milovidov 2021-11-14 01:44:08 +03:00 committed by GitHub
commit 5712f9077d
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3 changed files with 62 additions and 0 deletions

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@ -675,6 +675,34 @@ void BaseDaemon::initialize(Application & self)
if ((!log_path.empty() && is_daemon) || config().has("logger.stderr"))
{
std::string stderr_path = config().getString("logger.stderr", log_path + "/stderr.log");
/// Check that stderr is writable before freopen(),
/// since freopen() will make stderr invalid on error,
/// and logging to stderr will be broken,
/// so the following code (that is used in every program) will not write anything:
///
/// int main(int argc, char ** argv)
/// {
/// try
/// {
/// DB::SomeApp app;
/// return app.run(argc, argv);
/// }
/// catch (...)
/// {
/// std::cerr << DB::getCurrentExceptionMessage(true) << "\n";
/// return 1;
/// }
/// }
if (access(stderr_path.c_str(), W_OK))
{
int fd;
if ((fd = creat(stderr_path.c_str(), 0600)) == -1 && errno != EEXIST)
throw Poco::OpenFileException("File " + stderr_path + " (logger.stderr) is not writable");
if (fd != -1)
::close(fd);
}
if (!freopen(stderr_path.c_str(), "a+", stderr))
throw Poco::OpenFileException("Cannot attach stderr to " + stderr_path);

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@ -0,0 +1,3 @@
Ensure that not existing file still write an error to stderr
File /no/such/file (logger.stderr) is not writable
Ensure that the file will be created

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@ -0,0 +1,31 @@
#!/usr/bin/env bash
CUR_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
# shellcheck source=../shell_config.sh
. "$CUR_DIR"/../shell_config.sh
(
echo 'Ensure that not existing file still write an error to stderr'
test_dir=$(mktemp -d -t clickhouse.XXXXXX)
mkdir -p "$test_dir"
cd "$test_dir" || exit 1
$CLICKHOUSE_SERVER_BINARY -- --logger.stderr=/no/such/file |& grep -o 'File /no/such/file (logger.stderr) is not writable'
rm -fr "${test_dir:?}"
)
(
echo 'Ensure that the file will be created'
test_dir=$(mktemp -d -t clickhouse.XXXXXX)
mkdir -p "$test_dir"
cd "$test_dir" || exit 1
stderr=$(mktemp -t clickhouse.XXXXXX)
$CLICKHOUSE_SERVER_BINARY -- --logger.stderr="$stderr" 2>/dev/null
# -s -- check that stderr was created and is not empty
test -s "$stderr" || exit 2
rm "$stderr"
rm -fr "${test_dir:?}"
)