Remove cppcheck from CI, add to tools/

We don't enforce cppcheck through the CI, although it's there since
years. It runs on Ubuntu 18/20, so it's old. For folks, it's likely not
discoverable on how to run it locally. Let's make a fresh start.

This removes cppcheck from all CI-related code. Instead, it adds it
under tools/cppcheck/, including documentation on how to run it locally,
bare-matel or in docker.

Signed-off-by: Robert Schmidt <robert.schmidt@openairinterface.org>

tools/cppcheck/README.md

@@ -0,0 +1,28 @@
+<!-- SPDX-License-Identifier: CC-BY-4.0 -->
+
+# Static code analysis
+
+How to run static code analysis tool(s).
+
+[[_TOC_]]
+
+## cppcheck Overview
+
+This can run a (dockerized) cppcheck static code analysis. The docker-compose
+file represents the status as run as in the CI until it's removal (because it
+was not enforced). It is now here so that people could use it to find bugs (and
+use the tool more easily).
+
+## cppcheck Usage
+
+From the openairinterface5g root, simply run
+
+    ./tools/cppcheck/run-cppcheck.sh
+
+This will run cppcheck with options listed in this file, assuming you have it
+installed. Alternatively, you can run the CI version as of Ubuntu 20 with
+
+    cd tools/cppcheck && docker compose up --no-log-prefix
+
+You can upgrade to a newer version by modifying the `FROM` line in the
+docker-compose file.

tools/cppcheck/docker-compose.yaml

@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: MIT
+
+services:
+  cppcheck:
+    image: cppcheck
+    build:
+      dockerfile_inline: |
+        FROM ubuntu:focal
+        RUN DEBIAN_FRONTEND=noninteractive apt update && apt install -y cppcheck
+    volumes:
+      - ../../:/code/
+    command:
+      bash -c "cd /code/ && ./tools/cppcheck/run-cppcheck.sh"
+

tools/cppcheck/run-cppcheck.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+# SPDX-License-Identifier: MIT
+
+cppcheck --enable=warning --force \
+    --inline-suppr \
+    --quiet \
+    -i openair1/PHY/CODING/nrLDPC_decoder/nrLDPC_decoder.c \
+    --suppressions-list=tools/cppcheck/suppressions.list \
+    -I common/utils \
+    -I openair3/NAS/COMMON/UTIL \
+    -j`nproc` .

tools/cppcheck/suppressions.list

@@ -0,0 +1,94 @@
+// *INDENT-OFF*   cppcheck doesn't like "astyling" this file!!!!
+// SPDX-License-Identifier: LicenseRef-CSSL-1.0
+//*****************************************************************************
+//*****************************************************************************
+// section for "valid" memory leaks: the related functions are allocators and
+// the caller is responsible of freeing the memory. cppcheck has a mechanism
+// to check more accuretaly this, by defining callers responsible of freeing
+// but tools like valgring might be more suitable
+//
+//-----------------------------------------------------------------------------
+//    suppress error about keysP memory leak, free must be done by calling func
+memleak:common/utils/hashtable/obj_hashtable.c
+//-----------------------------------------------------------------------------
+//    suppress error about keys memory leak, free must be done by calling func
+memleak:openair2/UTIL/OMG/omg_hashtable.c
+//-----------------------------------------------------------------------------
+//     suppress error about data memory leak. This is the buffer where
+//    _emm_as_encode function creates the encoded buffer
+//
+memleak:openair3/NAS/UE/EMM/SAP/emm_as.c
+memleak:openair1/PHY/INIT/nr_init_ue.c
+//-----------------------------------------------------------------------------
+//*****************************************************************************
+// section for files not used in oai exec's included in CI.
+// Possibly candidates for removal otherwise should be documented and updated
+// for project rules enforcement
+// ----------------------------------------------------------------------------
+// likely sources for test programs, maintained?
+invalidPrintfArgType_sint:openair1/PHY/CODING/TESTBENCH/ltetest.c
+memleak:openair1/PHY/CODING/TESTBENCH/ltetest.c
+invalidPrintfArgType_sint:openair1/PHY/CODING/TESTBENCH/pdcch_test.c
+//
+//-----------------------------------------------------------------------------
+// is itti analyzer deprecated
+nullPointer:common/utils/itti_analyzer/itti_analyzer.c
+nullPointerRedundantCheck:common/utils/itti_analyzer/libbuffers/buffers.c
+doubleFree:common/utils/itti_analyzer/libbuffers/socket.c
+memleak:common/utils/itti_analyzer/libbuffers/socket.c
+memleak:common/utils/itti_analyzer/libparser/array_type.c
+memleak:common/utils/itti_analyzer/libui/ui_callbacks.c
+//-----------------------------------------------------------------------------
+// obviously never even compiled!!!
+syntaxError:openair1/SIMULATION/LTE_PHY/dlsim_tm4.c
+//-----------------------------------------------------------------------------
+// omg, otg commented out in cmakelist to be cleaned up definitely?
+arrayIndexOutOfBounds:openair2/UTIL/OMG/omg.c
+uninitvar:openair2/UTIL/OTG/otg_rx_socket.c
+//-----------------------------------------------------------------------------
+// cppcheck is not able to understand that buf is initialized at the first
+// iteration of the loop.
+nullPointer:common/utils/T/local_tracer.c:243
+//-----------------------------------------------------------------------------
+// once again cppcheck does not understand that fds is initialized in the
+// first iteration of the loop
+nullPointer:common/utils/T/tracer/multi.c:264
+nullPointer:common/utils/T/tracer/multi.c:265
+//-----------------------------------------------------------------------------
+// this file is used for testing the RLC V2 implementation, this error is
+// not a problem, the programmer has to know what she does when writing
+// the tests
+arrayIndexOutOfBounds:openair2/LAYER2/rlc_v2/tests/test.c:401
+//
+//-----------------------------------------------------------------------------
+// this file is used for testing the NR RLC implementation, this error is
+// not a problem, the programmer has to know what she does when writing
+// the tests
+arrayIndexOutOfBounds:openair2/LAYER2/nr_rlc/tests/test.c:451
+//
+//-----------------------------------------------------------------------------
+// cppcheck does not understand the different lengths of arrays
+arrayIndexOutOfBounds:openair1/SIMULATION/TOOLS/random_channel.c:705
+arrayIndexOutOfBounds:openair1/SIMULATION/TOOLS/random_channel.c:706
+//*****************************************************************************
+//
+// True problems we don't know how to fix, Suppression is commented out,
+// as these kind of problem need either to be fixed or can be suppressed
+// when fully uderstood
+//-----------------------------------------------------------------------------
+// the function [nv]fapi_pnf_p7_config_create should return
+// _this. _this points to a structure and a dynamically allocated field is
+// returned. cppcheck suspects _this will never be released, so do i
+// memleak:nfapi/open-nFAPI/pnf/src/pnf_p7_interface.c
+// memleak:nfapi/open-nFAPI/vnf/src/vnf_p7_interface.c
+//-----------------------------------------------------------------------------
+// may be security_data->kenb.value is released from calling functions. But even
+// when, for test, freeing it before returning from emm_proc_security_mode_command
+// which does the allocation, cppcheck complains. So something might be wrong...
+// memleak:openair3/NAS/UE/EMM/SecurityModeControl.c
+//-----------------------------------------------------------------------------
+// when used, nobody but the original developer can guess if sn_data_cnf is set or not
+// cppcheck found that in some cases it is not, code needs cleanup before fixing that...
+// uninitvar:openair2/LAYER2/RLC/AM_v9.3.0/rlc_am_status_report.c
+//*****************************************************************************
+// *INDENT-ON*