bpf/progs/test_map_init.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /* Copyright (c) 2020 Tessares SA <http://www.tessares.net> */
0003
0004 #include "vmlinux.h"
0005 #include <bpf/bpf_helpers.h>
0006
0007 __u64 inKey = 0;
0008 __u64 inValue = 0;
0009 __u32 inPid = 0;
0010
0011 struct {
0012     __uint(type, BPF_MAP_TYPE_PERCPU_HASH);
0013     __uint(max_entries, 2);
0014     __type(key, __u64);
0015     __type(value, __u64);
0016 } hashmap1 SEC(".maps");
0017
0018
0019 SEC("tp/syscalls/sys_enter_getpgid")
0020 int sysenter_getpgid(const void *ctx)
0021 {
0022     /* Just do it for once, when called from our own test prog. This
0023      * ensures the map value is only updated for a single CPU.
0024      */
0025     int cur_pid = bpf_get_current_pid_tgid() >> 32;
0026
0027     if (cur_pid == inPid)
0028         bpf_map_update_elem(&hashmap1, &inKey, &inValue, BPF_NOEXIST);
0029
0030     return 0;
0031 }
0032
0033 char _license[] SEC("license") = "GPL";