spl: ffi: catch panics in FFI layer to prevent caller crashes

[Yumasi]

What does this PR do?

This PR wraps the logic of the public functions of liddd_discovery.a with panic::catch_unwind to prevent crashes on eventual panics.
Now, in case the Rust code panics, it will be caught and dd_discovery_get_services will return NULL to signal an error occured and allow the caller to react accordingly.

Motivation

Prevent panics in Rust from crashing the whole system-probe in the future

Describe how you validated your changes

To verify the catch_unwind barrier works at the C FFI boundary, I built a small C program linked against libdd_discovery.a that called a temporary dd_test_panic() FFI function (added for this test, then removed) that panics internally inside catch_unwind.

Additional Notes

[agent-platform-auto-pr]

Files inventory check summary

File checks results against ancestor af001651:

Results for datadog-agent_7.79.0~devel.git.305.290efe8.pipeline.105291782-1_amd64.deb:

No change detected

[agent-platform-auto-pr]

Static quality checks

✅ Please find below the results from static quality gates
Comparison made with ancestor af00165
📊 Static Quality Gates Dashboard
🔗 SQG Job

30 successful checks with minimal change (< 2 KiB)

	Quality gate	Current Size
✅	agent_deb_amd64	753.077 MiB
✅	agent_deb_amd64_fips	710.016 MiB
✅	agent_heroku_amd64	313.321 MiB
✅	agent_rpm_amd64	753.060 MiB
✅	agent_rpm_amd64_fips	710.000 MiB
✅	agent_rpm_arm64	731.482 MiB
✅	agent_rpm_arm64_fips	691.443 MiB
✅	agent_suse_amd64	753.060 MiB
✅	agent_suse_amd64_fips	710.000 MiB
✅	agent_suse_arm64	731.482 MiB
✅	agent_suse_arm64_fips	691.443 MiB
✅	docker_agent_amd64	813.379 MiB
✅	docker_agent_arm64	816.572 MiB
✅	docker_agent_jmx_amd64	1004.295 MiB
✅	docker_agent_jmx_arm64	996.266 MiB
✅	docker_cluster_agent_amd64	203.945 MiB
✅	docker_cluster_agent_arm64	218.419 MiB
✅	docker_cws_instrumentation_amd64	7.142 MiB
✅	docker_cws_instrumentation_arm64	6.689 MiB
✅	docker_dogstatsd_amd64	39.234 MiB
✅	docker_dogstatsd_arm64	37.445 MiB
✅	dogstatsd_deb_amd64	29.878 MiB
✅	dogstatsd_deb_arm64	28.030 MiB
✅	dogstatsd_rpm_amd64	29.878 MiB
✅	dogstatsd_suse_amd64	29.878 MiB
✅	iot_agent_deb_amd64	43.285 MiB
✅	iot_agent_deb_arm64	40.332 MiB
✅	iot_agent_deb_armhf	41.080 MiB
✅	iot_agent_rpm_amd64	43.286 MiB
✅	iot_agent_suse_amd64	43.286 MiB

On-wire sizes (compressed)

	Quality gate	Change	Size (prev → curr → max)
✅	agent_deb_amd64	-17.83 KiB (0.01% reduction)	174.748 → 174.731 → 178.360
✅	agent_deb_amd64_fips	-21.01 KiB (0.01% reduction)	165.375 → 165.354 → 172.790
✅	agent_heroku_amd64	neutral	75.005 MiB → 79.970
✅	agent_rpm_amd64	-6.11 KiB (0.00% reduction)	177.595 → 177.589 → 181.830
✅	agent_rpm_amd64_fips	+22.16 KiB (0.01% increase)	167.625 → 167.647 → 173.370
✅	agent_rpm_arm64	+29.01 KiB (0.02% increase)	159.547 → 159.575 → 163.060
✅	agent_rpm_arm64_fips	-25.19 KiB (0.02% reduction)	151.435 → 151.411 → 156.170
✅	agent_suse_amd64	-6.11 KiB (0.00% reduction)	177.595 → 177.589 → 181.830
✅	agent_suse_amd64_fips	+22.16 KiB (0.01% increase)	167.625 → 167.647 → 173.370
✅	agent_suse_arm64	+29.01 KiB (0.02% increase)	159.547 → 159.575 → 163.060
✅	agent_suse_arm64_fips	-25.19 KiB (0.02% reduction)	151.435 → 151.411 → 156.170
✅	docker_agent_amd64	neutral	268.198 MiB → 272.480
✅	docker_agent_arm64	neutral	255.391 MiB → 261.060
✅	docker_agent_jmx_amd64	neutral	336.846 MiB → 341.100
✅	docker_agent_jmx_arm64	neutral	320.028 MiB → 325.620
✅	docker_cluster_agent_amd64	neutral	71.375 MiB → 72.920
✅	docker_cluster_agent_arm64	neutral	67.011 MiB → 68.220
✅	docker_cws_instrumentation_amd64	neutral	2.999 MiB → 3.330
✅	docker_cws_instrumentation_arm64	neutral	2.729 MiB → 3.090
✅	docker_dogstatsd_amd64	neutral	15.174 MiB → 15.820
✅	docker_dogstatsd_arm64	neutral	14.489 MiB → 14.830
✅	dogstatsd_deb_amd64	neutral	7.893 MiB → 8.790
✅	dogstatsd_deb_arm64	neutral	6.778 MiB → 7.710
✅	dogstatsd_rpm_amd64	neutral	7.905 MiB → 8.800
✅	dogstatsd_suse_amd64	neutral	7.905 MiB → 8.800
✅	iot_agent_deb_amd64	-5.63 KiB (0.05% reduction)	11.406 → 11.401 → 12.040
✅	iot_agent_deb_arm64	neutral	9.705 MiB → 10.450
✅	iot_agent_deb_armhf	neutral	9.942 MiB → 10.620
✅	iot_agent_rpm_amd64	neutral	11.418 MiB → 12.060
✅	iot_agent_suse_amd64	neutral	11.418 MiB → 12.060

[cit-pr-commenter-54b7da]

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: 2bd8be25-982b-4013-9136-c6ae833c58de

Baseline: af00165
Comparison: 290efe8
Diff

Optimization Goals: ✅ No significant changes detected

Experiments ignored for regressions

Regressions in experiments with settings containing erratic: true are ignored.

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	docker_containers_cpu	% cpu utilization	-2.61	[-5.56, +0.34]	1	Logs

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	quality_gate_metrics_logs	memory utilization	+0.53	[+0.28, +0.77]	1	Logs bounds checks dashboard
➖	ddot_metrics_sum_cumulativetodelta_exporter	memory utilization	+0.44	[+0.22, +0.67]	1	Logs
➖	quality_gate_idle	memory utilization	+0.41	[+0.36, +0.46]	1	Logs bounds checks dashboard
➖	otlp_ingest_logs	memory utilization	+0.34	[+0.25, +0.44]	1	Logs
➖	uds_dogstatsd_20mb_12k_contexts_20_senders	memory utilization	+0.15	[+0.09, +0.21]	1	Logs
➖	tcp_syslog_to_blackhole	ingress throughput	+0.06	[-0.09, +0.21]	1	Logs
➖	file_to_blackhole_1000ms_latency	egress throughput	+0.05	[-0.38, +0.47]	1	Logs
➖	file_to_blackhole_0ms_latency	egress throughput	+0.04	[-0.44, +0.53]	1	Logs
➖	ddot_logs	memory utilization	+0.02	[-0.04, +0.09]	1	Logs
➖	uds_dogstatsd_to_api	ingress throughput	+0.01	[-0.19, +0.21]	1	Logs
➖	uds_dogstatsd_to_api_v3	ingress throughput	+0.01	[-0.19, +0.21]	1	Logs
➖	file_to_blackhole_100ms_latency	egress throughput	+0.00	[-0.07, +0.08]	1	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	-0.00	[-0.11, +0.10]	1	Logs
➖	ddot_metrics	memory utilization	-0.01	[-0.19, +0.18]	1	Logs
➖	file_to_blackhole_500ms_latency	egress throughput	-0.01	[-0.40, +0.38]	1	Logs
➖	file_tree	memory utilization	-0.02	[-0.08, +0.04]	1	Logs
➖	ddot_metrics_sum_delta	memory utilization	-0.15	[-0.32, +0.02]	1	Logs
➖	ddot_metrics_sum_cumulative	memory utilization	-0.18	[-0.33, -0.04]	1	Logs
➖	quality_gate_idle_all_features	memory utilization	-0.24	[-0.28, -0.21]	1	Logs bounds checks dashboard
➖	otlp_ingest_metrics	memory utilization	-0.30	[-0.46, -0.14]	1	Logs
➖	docker_containers_memory	memory utilization	-0.77	[-0.84, -0.70]	1	Logs
➖	quality_gate_logs	% cpu utilization	-1.63	[-3.24, -0.02]	1	Logs bounds checks dashboard
➖	docker_containers_cpu	% cpu utilization	-2.61	[-5.56, +0.34]	1	Logs

Bounds Checks: ✅ Passed

perf	experiment	bounds_check_name	replicates_passed	observed_value	links
✅	docker_containers_cpu	simple_check_run	10/10	547 ≥ 26
✅	docker_containers_memory	memory_usage	10/10	273.32MiB ≤ 370MiB
✅	docker_containers_memory	simple_check_run	10/10	704 ≥ 26
✅	file_to_blackhole_0ms_latency	memory_usage	10/10	0.18GiB ≤ 1.20GiB
✅	file_to_blackhole_0ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_1000ms_latency	memory_usage	10/10	0.24GiB ≤ 1.20GiB
✅	file_to_blackhole_1000ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_100ms_latency	memory_usage	10/10	0.20GiB ≤ 1.20GiB
✅	file_to_blackhole_100ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_500ms_latency	memory_usage	10/10	0.22GiB ≤ 1.20GiB
✅	file_to_blackhole_500ms_latency	missed_bytes	10/10	0B = 0B
✅	quality_gate_idle	intake_connections	10/10	3 = 3	bounds checks dashboard
✅	quality_gate_idle	memory_usage	10/10	173.35MiB ≤ 175MiB	bounds checks dashboard
✅	quality_gate_idle_all_features	intake_connections	10/10	3 = 3	bounds checks dashboard
✅	quality_gate_idle_all_features	memory_usage	10/10	491.59MiB ≤ 550MiB	bounds checks dashboard
✅	quality_gate_logs	intake_connections	10/10	4 ≤ 6	bounds checks dashboard
✅	quality_gate_logs	memory_usage	10/10	205.75MiB ≤ 220MiB	bounds checks dashboard
✅	quality_gate_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_metrics_logs	cpu_usage	10/10	353.31 ≤ 2000	bounds checks dashboard
✅	quality_gate_metrics_logs	intake_connections	10/10	4 ≤ 6	bounds checks dashboard
✅	quality_gate_metrics_logs	memory_usage	10/10	416.55MiB ≤ 475MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard

Explanation

Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%

Performance changes are noted in the perf column of each table:

• ✅ = significantly better comparison variant performance
• ❌ = significantly worse comparison variant performance
• ➖ = no significant change in performance

A regression test is an A/B test of target performance in a repeatable rig, where "performance" is measured as "comparison variant minus baseline variant" for an optimization goal (e.g., ingress throughput). Due to intrinsic variability in measuring that goal, we can only estimate its mean value for each experiment; we report uncertainty in that value as a 90.00% confidence interval denoted "Δ mean % CI".

For each experiment, we decide whether a change in performance is a "regression" -- a change worth investigating further -- if all of the following criteria are true:

1. Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.

2. Its 90.00% confidence interval "Δ mean % CI" does not contain zero, indicating that if our statistical model is accurate, there is at least a 90.00% chance there is a difference in performance between baseline and comparison variants.

3. Its configuration does not mark it "erratic".

CI Pass/Fail Decision

✅ Passed. All Quality Gates passed.

• quality_gate_metrics_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.