php-ebpf/tests/hash_table_test.php

<?php
/*
 * Copyright 2024 carl.guo <[email protected]>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

$prog = <<<EOT
BPF_HASH(counts, u32);

int kprobe__do_sys_openat2(struct pt_regs *ctx) {
    u32 key = 0;
    u64 *val, zero = 0;
    
    val = counts.lookup_or_init(&key, &zero);
    (*val)++;
    
    bpf_trace_printk("openat2 called %d times\\n", *val);
    return 0;
}
EOT;

try {
    $bpf = new Bpf(["text" => $prog]);
    echo "BPF program loaded successfully\n";
    
    // Get the hash table
    $counts = $bpf->get_table("counts");
    
    // Start monitoring
    echo "Monitoring openat2 syscalls with counter...\n";
    while (true) {
        try {
            list($task, $pid, $cpu, $flags, $ts, $msg) = $bpf->trace_fields();
            printf("%-18.9f %-16s %-6d %s\n", $ts, $task, $pid, $msg);
            
            // Print current count
            $values = $counts->values();
            foreach ($values as $key => $value) {
                echo "Total calls: " . $value . "\n";
            }
            
            flush();
        } catch (Exception $e) {
            continue;
        }
    }
} catch (Exception $e) {
    echo "Error: " . $e->getMessage() . "\n";
    exit(1);
}