Revert "SystemSan: arbitrary DNS resolution detection"

[oliverchang]

Reverts #8448.

Build was broken in several places.

Even once fixed, the target_dns example didn't work.

[oliverchang]

@catenacyber can you please fix these? I fixed the build locally myself, but the target_dns example didn't crash for me.

[DonggeLiu]

Noted.
Would you mind sharing the log messages of build failures?
I am happy to add some test cases to capture them in the future.

[oliverchang]

These are the build errors:

rm -f SystemSan /tmp/tripwire target target_file target_dns
clang++ -std=c++17 -Wall -Wextra -O3 -g3 -lpthread -o SystemSan SystemSan.cpp inspect_dns.cpp inspect_utils.cpp
inspect_dns.cpp:164:5: error: no matching function for call to 'report_bug'
    report_bug(kArbitraryDomainNameResolution);
    ^~~~~~~~~~
./inspect_utils.h:28:6: note: candidate function not viable: requires 2 arguments, but 1 was provided
void report_bug(std::string bug_type, pid_t tid);
     ^
1 error generated.
inspect_utils.cpp:32:13: error: no template named 'map' in namespace 'std'; did you mean 'max'?
extern std::map<pid_t, ThreadParent> root_pids;
       ~~~~~^~~
            max
/usr/bin/../lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/bits/stl_algobase.h:254:5: note: 'max' declared here
    max(const _Tp& __a, const _Tp& __b)
    ^
inspect_utils.cpp:32:24: error: use of undeclared identifier 'ThreadParent'
extern std::map<pid_t, ThreadParent> root_pids;
                       ^
inspect_utils.cpp:60:17: error: use of undeclared identifier 'root_pids'; did you mean 'g_root_pid'?
  auto parent = root_pids[tid];
                ^~~~~~~~~
                g_root_pid
inspect_utils.cpp:31:14: note: 'g_root_pid' declared here
extern pid_t g_root_pid;
             ^
inspect_utils.cpp:60:26: error: subscripted value is not an array, pointer, or vector
  auto parent = root_pids[tid];
                ~~~~~~~~~^~~~
inspect_utils.cpp:67:14: error: use of undeclared identifier 'root_pids'; did you mean 'g_root_pid'?
    parent = root_pids[parent.parent_tid];
             ^~~~~~~~~
             g_root_pid
inspect_utils.cpp:31:14: note: 'g_root_pid' declared here
extern pid_t g_root_pid;
             ^
5 errors generated.
make: *** [Makefile:8: SystemSan] Error 1

They're easily fixed, but even once they are it doesn't work.

[catenacyber]

Ah indeed, #8448 was not rebased after merge of #8615

A new PR is coming