Add support to dump processLRU

This patch adds support to print the contents of process cache. This may be useful during debugging.

Example:

$ sudo ./tetra dump processCache
{"process":{"exec_id":"YXBhcGFnLXVidW50dS1kZXY6MTAwNjgwMDAwMDAwOjE4OTg=", "pid":1898, "uid":1010, "cwd":"/home/apapag", "binary":"/home/apapag/.vscode-server/cli/servers/Stable-fee1edb8d6d72a0ddff41e5f71a671c23ed924b9/server/node", "arguments":"--dns-result-order=ipv4first /home/apapag/.vscode-server/cli/servers/Stable-fee1edb8d6d72a0ddff41e5f71a671c23ed924b9/server/out/bootstrap-fork --type=extensionHost --transformURIs --useHostProxy=false", "flags":"procFS auid", "start_time":"2024-09-05T07:00:23.274832687Z", "auid":1010, "parent_exec_id":"YXBhcGFnLXVidW50dS1kZXY6ODk5NTAwMDAwMDA6MTc3Ng==", "tid":1898}, "color":"inUse", "refcnt":5, "refcntOps":{"parent++":346, "parent--":342, "process++":1}}
{"process":{"exec_id":"YXBhcGFnLXVidW50dS1kZXY6MTU2OTQ0MDAwMDAwMDozMzM3OA==", "pid":33378, "uid":1010, "cwd":"/home/apapag/tetragon", "binary":"/usr/bin/bash", "flags":"procFS auid", "start_time":"2024-09-05T07:24:52.034832554Z", "auid":1010, "parent_exec_id":"YXBhcGFnLXVidW50dS1kZXY6MTU2OTIyMDAwMDAwMDozMzM3Nw==", "tid":33378}, "color":"inUse", "refcnt":2, "refcntOps":{"parent++":30, "parent--":29, "process++":1}}
{"process":{"exec_id":"YXBhcGFnLXVidW50dS1kZXY6Mjg1MjM2Nzc1Nzc4NDo1MjE1Mg==", "pid":52152, "uid":0, "cwd":"/home/apapag/tetragon", "binary":"/usr/bin/sudo", "arguments":"./tetra dump processCache --skip-zero-refcnt", "flags":"execve clone", "start_time":"2024-09-05T07:46:14.962590751Z", "auid":1010, "parent_exec_id":"YXBhcGFnLXVidW50dS1kZXY6MTU2OTQ0MDAwMDAwMDozMzM3OA==", "tid":52152}, "color":"inUse", "refcnt":2, "refcntOps":{"parent++":1, "process++":1}}
{"process":{"exec_id":"YXBhcGFnLXVidW50dS1kZXY6Mjg1MjM3NjMxOTI2OTo1MjE1NA==", "pid":52154, "uid":0, "cwd":"/home/apapag/tetragon", "binary":"/home/apapag/tetragon/tetra", "arguments":"dump processCache --skip-zero-refcnt", "flags":"execve clone", "start_time":"2024-09-05T07:46:14.971151996Z", "auid":1010, "parent_exec_id":"YXBhcGFnLXVidW50dS1kZXY6Mjg1MjM3NTU4MTQxMTo1MjE1Mw==", "tid":52154}, "color":"inUse", "refcnt":1, "refcntOps":{"process++":1}}
{"process":{"exec_id":"YXBhcGFnLXVidW50dS1kZXY6Mjg1MjM3NTU4MTQxMTo1MjE1Mw==", "pid":52153, "uid":0, "cwd":"/home/apapag/tetragon", "binary":"/usr/bin/sudo", "arguments":"./tetra dump processCache --skip-zero-refcnt", "flags":"execve", "start_time":"2024-09-05T07:46:14.970414578Z", "auid":1010, "parent_exec_id":"YXBhcGFnLXVidW50dS1kZXY6Mjg1MjM2Nzc1Nzc4NDo1MjE1Mg==", "refcnt":1, "tid":52153}, "color":"inUse", "refcnt":2, "refcntOps":{"parent++":2, "parent--":1, "process++":1}}
[...]

We also provide "--skip-zero-refcnt" command line argument to print only the entries with refcnt not equals to zero.

$ sudo ./tetra dump processCache --skip-zero-refcnt
{"process":{"exec_id":"YXBhcGFnLXVidW50dS1kZXY6MTAwNjgwMDAwMDAwOjE4OTg=", "pid":1898, "uid":1010, "cwd":"/home/apapag", "binary":"/home/apapag/.vscode-server/cli/servers/Stable-fee1edb8d6d72a0ddff41e5f71a671c23ed924b9/server/node", "arguments":"--dns-result-order=ipv4first /home/apapag/.vscode-server/cli/servers/Stable-fee1edb8d6d72a0ddff41e5f71a671c23ed924b9/server/out/bootstrap-fork --type=extensionHost --transformURIs --useHostProxy=false", "flags":"procFS auid", "start_time":"2024-09-05T07:00:23.274832687Z", "auid":1010, "parent_exec_id":"YXBhcGFnLXVidW50dS1kZXY6ODk5NTAwMDAwMDA6MTc3Ng==", "tid":1898}, "color":"inUse", "refcnt":5, "refcntOps":{"parent++":346, "parent--":342, "process++":1}}
{"process":{"exec_id":"YXBhcGFnLXVidW50dS1kZXY6MTU2OTQ0MDAwMDAwMDozMzM3OA==", "pid":33378, "uid":1010, "cwd":"/home/apapag/tetragon", "binary":"/usr/bin/bash", "flags":"procFS auid", "start_time":"2024-09-05T07:24:52.034832554Z", "auid":1010, "parent_exec_id":"YXBhcGFnLXVidW50dS1kZXY6MTU2OTIyMDAwMDAwMDozMzM3Nw==", "tid":33378}, "color":"inUse", "refcnt":2, "refcntOps":{"parent++":30, "parent--":29, "process++":1}}
{"process":{"exec_id":"YXBhcGFnLXVidW50dS1kZXY6Mjg1MjM2Nzc1Nzc4NDo1MjE1Mg==", "pid":52152, "uid":0, "cwd":"/home/apapag/tetragon", "binary":"/usr/bin/sudo", "arguments":"./tetra dump processCache --skip-zero-refcnt", "flags":"execve clone", "start_time":"2024-09-05T07:46:14.962590751Z", "auid":1010, "parent_exec_id":"YXBhcGFnLXVidW50dS1kZXY6MTU2OTQ0MDAwMDAwMDozMzM3OA==", "tid":52152}, "color":"inUse", "refcnt":2, "refcntOps":{"parent++":1, "process++":1}}
{"process":{"exec_id":"YXBhcGFnLXVidW50dS1kZXY6Mjg1MjM3NjMxOTI2OTo1MjE1NA==", "pid":52154, "uid":0, "cwd":"/home/apapag/tetragon", "binary":"/home/apapag/tetragon/tetra", "arguments":"dump processCache --skip-zero-refcnt", "flags":"execve clone", "start_time":"2024-09-05T07:46:14.971151996Z", "auid":1010, "parent_exec_id":"YXBhcGFnLXVidW50dS1kZXY6Mjg1MjM3NTU4MTQxMTo1MjE1Mw==", "tid":52154}, "color":"inUse", "refcnt":1, "refcntOps":{"process++":1}}
{"process":{"exec_id":"YXBhcGFnLXVidW50dS1kZXY6Mjg1MjM3NTU4MTQxMTo1MjE1Mw==", "pid":52153, "uid":0, "cwd":"/home/apapag/tetragon", "binary":"/usr/bin/sudo", "arguments":"./tetra dump processCache --skip-zero-refcnt", "flags":"execve", "start_time":"2024-09-05T07:46:14.970414578Z", "auid":1010, "parent_exec_id":"YXBhcGFnLXVidW50dS1kZXY6Mjg1MjM2Nzc1Nzc4NDo1MjE1Mg==", "refcnt":1, "tid":52153}, "color":"inUse", "refcnt":2, "refcntOps":{"parent++":2, "parent--":1, "process++":1}}
[...]

Signed-off-by: Anastasios Papagiannis <[email protected]>