Since the previous commit, some strings logged by write_log() contain a
literal newline, which leads to errors like this one:
> # time="2020-06-07T15:41:37Z" level=error msg="failed to decode \"{\\\"level\\\":\\\"debug\\\", \\\"msg\\\": \\\"nsexec-0[2265]: update /proc/2266/uid_map to '0 1000 1\\n\" to json: invalid character '\\n' in string literal"
The fix is to escape such characters.
Add a simple (as much as it can be) routine which implements JSON string
escaping as required by RFC4627, section 2.5, plus escaping of DEL (0x7f)
character (not required, but allowed by the standard, and usually done
by tools such as jq).
As much as I hate to code something like this, I was not able to find
a ready to consume and decent C implementation (not using glib).
Added a test case (and some additional asserts in C code, conditionally
enabled by the test case) to make sure the implementation is correct.
The test case have to live in a separate directory so we can use
different C flags to compile the test, and use C from go test.
[v2: try to simplify the code, add more tests]
[v3: don't do exit(1), try returning an error instead]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Aleksa Sarai