out_cloudwatch: fix integer overflow in timestamps (issue #3640)

[nbertram]

This is the simplest fix to avoid integer overflows when multiplying (32 bit) timestamp values by 1000 on 32 bit systems (ARMv7). See the related issue for context.

Fixes #3640

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Testing
Before we can approve your change; please submit the following in a comment:

• [See issue] Example configuration file for the change
• [TODO] Debug log output from testing the change

• [TODO] Attached Valgrind output that shows no leaks or memory corruption was found

Documentation

• [N/A] Documentation required for this feature

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Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

[nbertram]

By the way, the test suite is already failing on ARMv7, but not for Cloudwatch. There doesn't seem to be a test for the formatting of the log HTTP messages.

93% tests passed, 5 tests failed out of 68

Label Time Summary:
internal    =  34.61 sec*proc (31 tests)
runtime     = 875.80 sec*proc (35 tests)

Total Test time (real) = 918.49 sec

The following tests FAILED:
	  4 - flb-rt-in_proc (Failed)
	 21 - flb-rt-out_elasticsearch (Failed)
	 35 - flb-rt-out_td (Failed)
	 44 - flb-it-network (Failed)
	 63 - flb-it-aws_util (Failed)

[PettitWesley]

@edsiper can you review this one- cross-compiler/cross platform stuff is completely outside of my expertise.

@nbertram make sure you submit a PR for this same commit (after its approved) against the 1.7 branch as well so that we can get the fix released in the next 1.7 patch.

[nokute78]

@nbertram Can you check DCO error ?
https://probot.github.io/apps/dco/

@edsiper @PettitWesley
I confirmed. The patch is looks good to me.

I tested a test code on Ubuntu 20.04(x86_64)

environment setting

sudo apt install g++-arm-linux-gnueabihf
sudo apt-get install qemu-system-arm

test code

timestamp is current implementation.
timestamp_patch is fixed implementation by this PR.

#include <stdio.h>
#include <time.h>

int main() {
  unsigned long long timestamp;
  unsigned long long timestamp_patch;
  time_t sec = 1624437067;
  long nsec = 456789000;


  timestamp = (unsigned long long)(sec * 1000 +
                                   nsec / 1000000);

  timestamp_patch  = (unsigned long long)(sec * 1000ull +
                                          nsec / 1000000);

  printf("timestamp    =%lld\n", timestamp);
  printf("timestamp(p) =%lld\n", timestamp_patch);
}

Output

timestamp(p) is right value.

$ arm-linux-gnueabihf-gcc  -Wall -o a --static a.c
$ ./a
timestamp    =939429568
timestamp(p) =1624437067456

[PettitWesley]

@nbertram Can you please fix the DCO error?

Commit the message like this as an example:

git commit --sign -m "..."

[PettitWesley]

@edsiper What should we do to get this fix merged? Should we take the same changes and re-commit them and attribute them to @nbertram?

[nbertram]

Sorry I'll get on to this shorty. It's got an entry in my todo list now!

[nbertram]

@PettitWesley sorry for the delay, have added the DCO.

Anything else you need from me?

[nokute78]

Thank you.