diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/test_legacy_printk.c')
-rw-r--r-- | tools/testing/selftests/bpf/progs/test_legacy_printk.c | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_legacy_printk.c b/tools/testing/selftests/bpf/progs/test_legacy_printk.c new file mode 100644 index 0000000000..42718cd8e6 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_legacy_printk.c @@ -0,0 +1,73 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include <linux/bpf.h> +#define BPF_NO_GLOBAL_DATA +#include <bpf/bpf_helpers.h> + +char LICENSE[] SEC("license") = "GPL"; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, int); + __uint(max_entries, 1); +} my_pid_map SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, int); + __uint(max_entries, 1); +} res_map SEC(".maps"); + +volatile int my_pid_var = 0; +volatile int res_var = 0; + +SEC("tp/raw_syscalls/sys_enter") +int handle_legacy(void *ctx) +{ + int zero = 0, *my_pid, cur_pid, *my_res; + + my_pid = bpf_map_lookup_elem(&my_pid_map, &zero); + if (!my_pid) + return 1; + + cur_pid = bpf_get_current_pid_tgid() >> 32; + if (cur_pid != *my_pid) + return 1; + + my_res = bpf_map_lookup_elem(&res_map, &zero); + if (!my_res) + return 1; + + if (*my_res == 0) + /* use bpf_printk() in combination with BPF_NO_GLOBAL_DATA to + * force .rodata.str1.1 section that previously caused + * problems on old kernels due to libbpf always tried to + * create a global data map for it + */ + bpf_printk("Legacy-case bpf_printk test, pid %d\n", cur_pid); + *my_res = 1; + + return *my_res; +} + +SEC("tp/raw_syscalls/sys_enter") +int handle_modern(void *ctx) +{ + int cur_pid; + + cur_pid = bpf_get_current_pid_tgid() >> 32; + if (cur_pid != my_pid_var) + return 1; + + if (res_var == 0) + /* we need bpf_printk() to validate libbpf logic around unused + * global maps and legacy kernels; see comment in handle_legacy() + */ + bpf_printk("Modern-case bpf_printk test, pid %d\n", cur_pid); + res_var = 1; + + return res_var; +} |