out_oracle_log_analytics: minor fixes

[nokute78]

This patch is to

1. Remove some flb_errno. We should use flb_errno for syscall error.
2. Release key to prevent leak.
3. Fix mk_list handling. Always initialize mk_list.
4. Set NULL to prevent double free.

3 is to fix following SIGSEGV. It caused by touching not initalized mk_list.

$ bin/fluent-bit -i dummy -o oracle_log_analytics 
Fluent Bit v2.1.10
* Copyright (C) 2015-2022 The Fluent Bit Authors
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

[2023/09/24 09:20:53] [engine] caught signal (SIGSEGV)
[2023/09/24 09:20:53] [ info] [fluent bit] version=2.1.10, commit=2631ca199e, pid=60103
[2023/09/24 09:20:53] [ info] [storage] ver=1.2.0, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2023/09/24 09:20:53] [ info] [cmetrics] version=0.6.3
[2023/09/24 09:20:53] [ info] [ctraces ] version=0.3.1
[2023/09/24 09:20:53] [ info] [input:dummy:dummy.0] initializing
[2023/09/24 09:20:53] [ info] [input:dummy:dummy.0] storage_strategy='memory' (memory only)
[2023/09/24 09:20:53] [error] [/home/taka/git/fluent-bit/plugins/out_oracle_log_analytics/oci_logan_conf.c:293 errno=0] Success
[2023/09/24 09:20:53] [error] [output:oracle_log_analytics:oracle_log_analytics.0] log source name and log group id are required
#0  0x563a2fe7abae      in  metadata_fields_destroy() at plugins/out_oracle_log_analytics/oci_logan_conf.c:438
#1  0x563a2fe7ae18      in  flb_oci_logan_conf_destroy() at plugins/out_oracle_log_analytics/oci_logan_conf.c:489
#2  0x563a2fe7a278      in  flb_oci_logan_conf_create() at plugins/out_oracle_log_analytics/oci_logan_conf.c:296
#3  0x563a2fe72a01      in  cb_oci_logan_init() at plugins/out_oracle_log_analytics/oci_logan.c:533
#4  0x563a2fa21227      in  flb_output_init_all() at src/flb_output.c:1301
#5  0x563a2fa48e28      in  flb_engine_start() at src/flb_engine.c:790
#6  0x563a2f9e3944      in  flb_lib_worker() at src/flb_lib.c:638
#7  0x7fb2f6a94b42      in  start_thread() at /sysdeps/unix/sysv/linux/rseq-internal.h:442
#8  0x7fb2f6b269ff      in  ???() at /x86_64/clone3.S:81
#9  0xffffffffffffffff  in  ???() at ???:0
Aborted (core dumped)

4 is to fix following double free.

$ valgrind --leak-check=full  bin/fluent-bit -c a.conf 
==60108== Memcheck, a memory error detector
==60108== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==60108== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==60108== Command: bin/fluent-bit -c a.conf
==60108== 
Fluent Bit v2.1.10
* Copyright (C) 2015-2022 The Fluent Bit Authors
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

[2023/09/24 09:21:37] [ info] [fluent bit] version=2.1.10, commit=2631ca199e, pid=60108
[2023/09/24 09:21:37] [ info] [storage] ver=1.2.0, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2023/09/24 09:21:37] [ info] [cmetrics] version=0.6.3
[2023/09/24 09:21:37] [ info] [ctraces ] version=0.3.1
[2023/09/24 09:21:37] [ info] [input:dummy:dummy.0] initializing
[2023/09/24 09:21:37] [ info] [input:dummy:dummy.0] storage_strategy='memory' (memory only)
==60108== Thread 2 flb-pipeline:
==60108== Invalid free() / delete / delete[] / realloc()
==60108==    at 0x484B27F: free (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==60108==    by 0x67016E: mk_mem_free (mk_memory.h:102)
==60108==    by 0x674C3B: load_oci_credentials (oci_logan_conf.c:159)
==60108==    by 0x67543C: flb_oci_logan_conf_create (oci_logan_conf.c:327)
==60108==    by 0x66DA01: cb_oci_logan_init (oci_logan.c:533)
==60108==    by 0x21C227: flb_output_init_all (flb_output.c:1301)
==60108==    by 0x243E28: flb_engine_start (flb_engine.c:790)
==60108==    by 0x1DE944: flb_lib_worker (flb_lib.c:638)
==60108==    by 0x4FF3B42: start_thread (pthread_create.c:442)
==60108==    by 0x5084BB3: clone (clone.S:100)
==60108==  Address 0x547df70 is 0 bytes inside a block of size 6 free'd
==60108==    at 0x484B27F: free (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==60108==    by 0x67016E: mk_mem_free (mk_memory.h:102)
==60108==    by 0x674942: load_oci_credentials (oci_logan_conf.c:123)
==60108==    by 0x67543C: flb_oci_logan_conf_create (oci_logan_conf.c:327)
==60108==    by 0x66DA01: cb_oci_logan_init (oci_logan.c:533)
==60108==    by 0x21C227: flb_output_init_all (flb_output.c:1301)
==60108==    by 0x243E28: flb_engine_start (flb_engine.c:790)
==60108==    by 0x1DE944: flb_lib_worker (flb_lib.c:638)
==60108==    by 0x4FF3B42: start_thread (pthread_create.c:442)
==60108==    by 0x5084BB3: clone (clone.S:100)
==60108==  Block was alloc'd at
==60108==    at 0x4848899: malloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==60108==    by 0xE5591D: mk_mem_alloc (mk_memory.h:53)
==60108==    by 0xE56733: mk_string_copy_substr (mk_string.c:585)
==60108==    by 0x67486C: load_oci_credentials (oci_logan_conf.c:117)
==60108==    by 0x67543C: flb_oci_logan_conf_create (oci_logan_conf.c:327)
==60108==    by 0x66DA01: cb_oci_logan_init (oci_logan.c:533)
==60108==    by 0x21C227: flb_output_init_all (flb_output.c:1301)
==60108==    by 0x243E28: flb_engine_start (flb_engine.c:790)
==60108==    by 0x1DE944: flb_lib_worker (flb_lib.c:638)
==60108==    by 0x4FF3B42: start_thread (pthread_create.c:442)
==60108==    by 0x5084BB3: clone (clone.S:100)
==60108== 

---

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

• Example configuration file for the change
• Debug log output from testing the change

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

If this is a change to packaging of containers or native binaries then please confirm it works for all targets.

• [N/A] Run local packaging test showing all targets (including any new ones) build.
• [N/A] Set ok-package-test label to test for all targets (requires maintainer to do).

Documentation

• [N/A] Documentation required for this feature

Backporting

• [N/A] Backport to latest stable release.

Configuration

[INPUT]
    Name dummy

[OUTPUT]
    name  oracle_log_analytics
    oci_la_log_source_name hoge
    oci_la_log_group_id hoge
    config_file_location a.conf

Debug/Valgrind output

Valgrind reported error that is not related this PR.

$ valgrind --leak-check=full  bin/fluent-bit -c a.conf 
==57351== Memcheck, a memory error detector
==57351== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==57351== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==57351== Command: bin/fluent-bit -c a.conf
==57351== 
Fluent Bit v2.1.10
* Copyright (C) 2015-2022 The Fluent Bit Authors
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

[2023/09/24 09:15:35] [ info] [fluent bit] version=2.1.10, commit=2631ca199e, pid=57351
[2023/09/24 09:15:35] [ info] [storage] ver=1.2.0, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2023/09/24 09:15:35] [ info] [cmetrics] version=0.6.3
[2023/09/24 09:15:35] [ info] [ctraces ] version=0.3.1
[2023/09/24 09:15:35] [ info] [input:dummy:dummy.0] initializing
[2023/09/24 09:15:35] [ info] [input:dummy:dummy.0] storage_strategy='memory' (memory only)
[2023/09/24 09:15:35] [error] [/home/taka/git/fluent-bit/plugins/out_oracle_log_analytics/oci_logan_conf.c:170 errno=0] Success
[2023/09/24 09:15:35] [error] [/home/taka/git/fluent-bit/plugins/out_oracle_log_analytics/oci_logan_conf.c:331 errno=0] Success
[2023/09/24 09:15:35] [error] [output:oracle_log_analytics:oracle_log_analytics.0] cannot initialize plugin
[2023/09/24 09:15:35] [error] [output] failed to initialize 'oracle_log_analytics' plugin
[2023/09/24 09:15:35] [error] [engine] output initialization failed
[2023/09/24 09:15:35] [error] [lib] backend failed
[2023/09/24 09:15:36] [ info] [input] pausing dummy.0
==57351== 
==57351== HEAP SUMMARY:
==57351==     in use at exit: 7 bytes in 1 blocks
==57351==   total heap usage: 1,478 allocs, 1,477 frees, 287,329 bytes allocated
==57351== 
==57351== 7 bytes in 1 blocks are definitely lost in loss record 1 of 1
==57351==    at 0x4848899: malloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==57351==    by 0x1C4E60: flb_malloc (flb_mem.h:80)
==57351==    by 0x1C514A: flb_strndup (flb_str.h:34)
==57351==    by 0x1C51B1: flb_strdup (flb_str.h:46)
==57351==    by 0x1C781C: flb_main (fluent-bit.c:970)
==57351==    by 0x1C8594: main (fluent-bit.c:1415)
==57351== 
==57351== LEAK SUMMARY:
==57351==    definitely lost: 7 bytes in 1 blocks
==57351==    indirectly lost: 0 bytes in 0 blocks
==57351==      possibly lost: 0 bytes in 0 blocks
==57351==    still reachable: 0 bytes in 0 blocks
==57351==         suppressed: 0 bytes in 0 blocks
==57351== 
==57351== For lists of detected and suppressed errors, rerun with: -s
==57351== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

---

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.

[nokute78]

I merged the branch with master

[patrick-stephens]

@edsiper apologies if already discussed but should @adiforluls be added as code-owner for this plugin?

[adiforluls]

Thanks for the fixes @nokute78, LGTM

[github-actions]

This PR is stale because it has been open 45 days with no activity. Remove stale label or comment or this will be closed in 10 days.

[nokute78]

@edsiper @leonardo-albertovich ping

[github-actions]

This PR is stale because it has been open 45 days with no activity. Remove stale label or comment or this will be closed in 10 days.

[github-actions]

This PR is stale because it has been open 45 days with no activity. Remove stale label or comment or this will be closed in 10 days.