linux-stable/tools/testing/selftests/bpf/progs/test_snprintf_single.c
Andrii Nakryiko 256eab48e7 selftests/bpf: Stop using static variables for passing data to/from user-space
In preparation of skipping emitting static variables in BPF skeletons, switch
all current selftests uses of static variables to pass data between BPF and
user-space to use global variables.

All non-read-only `static volatile` variables become just plain global
variables by dropping `static volatile` part.

Read-only `static volatile const` variables, though, still require `volatile`
modifier, otherwise compiler will ignore whatever values are set from
user-space.

Few static linker tests are using name-conflicting static variables to
validate that static linker still properly handles static variables and
doesn't trip up on name conflicts.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210507054119.270888-4-andrii@kernel.org
2021-05-11 15:07:17 -07:00

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C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Google LLC. */
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
/* The format string is filled from the userspace such that loading fails */
const char fmt[10];
SEC("raw_tp/sys_enter")
int handler(const void *ctx)
{
unsigned long long arg = 42;
bpf_snprintf(NULL, 0, fmt, &arg, sizeof(arg));
return 0;
}
char _license[] SEC("license") = "GPL";