Tests verifying snprintf()ing of various data structures, flags combinations using a tp_btf program. Tests are skipped if __builtin_btf_type_id is not available to retrieve BTF type ids.
Signed-off-by: Alan Maguire alan.maguire@oracle.com --- .../selftests/bpf/prog_tests/snprintf_btf.c | 60 +++++ .../selftests/bpf/progs/netif_receive_skb.c | 249 +++++++++++++++++++++ 2 files changed, 309 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/snprintf_btf.c create mode 100644 tools/testing/selftests/bpf/progs/netif_receive_skb.c
diff --git a/tools/testing/selftests/bpf/prog_tests/snprintf_btf.c b/tools/testing/selftests/bpf/prog_tests/snprintf_btf.c new file mode 100644 index 0000000..3a8ecf8 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/snprintf_btf.c @@ -0,0 +1,60 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <test_progs.h> +#include <linux/btf.h> +#include "netif_receive_skb.skel.h" + +/* Demonstrate that bpf_snprintf_btf succeeds and that various data types + * are formatted correctly. + */ +void test_snprintf_btf(void) +{ + struct netif_receive_skb *skel; + struct netif_receive_skb__bss *bss; + int err, duration = 0; + + skel = netif_receive_skb__open(); + if (CHECK(!skel, "skel_open", "failed to open skeleton\n")) + return; + + err = netif_receive_skb__load(skel); + if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err)) + goto cleanup; + + bss = skel->bss; + + err = netif_receive_skb__attach(skel); + if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err)) + goto cleanup; + + /* generate receive event */ + system("ping -c 1 127.0.0.1 > /dev/null"); + + if (bss->skip) { + printf("%s:SKIP:no __builtin_btf_type_id\n", __func__); + test__skip(); + goto cleanup; + } + + /* + * Make sure netif_receive_skb program was triggered + * and it set expected return values from bpf_trace_printk()s + * and all tests ran. + */ + if (CHECK(bss->ret <= 0, + "bpf_snprintf_btf: got return value", + "ret <= 0 %ld test %d\n", bss->ret, bss->ran_subtests)) + goto cleanup; + + if (CHECK(bss->ran_subtests == 0, "check if subtests ran", + "no subtests ran, did BPF program run?")) + goto cleanup; + + if (CHECK(bss->num_subtests != bss->ran_subtests, + "check all subtests ran", + "only ran %d of %d tests\n", bss->num_subtests, + bss->ran_subtests)) + goto cleanup; + +cleanup: + netif_receive_skb__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/netif_receive_skb.c b/tools/testing/selftests/bpf/progs/netif_receive_skb.c new file mode 100644 index 0000000..b873d80 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/netif_receive_skb.c @@ -0,0 +1,249 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020, Oracle and/or its affiliates. */ + +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> +#include <bpf/bpf_core_read.h> + +#include <errno.h> + +long ret = 0; +int num_subtests = 0; +int ran_subtests = 0; +bool skip = false; + +#define STRSIZE 2048 +#define EXPECTED_STRSIZE 256 + +#ifndef ARRAY_SIZE +#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) +#endif + +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); + __uint(max_entries, 1); + __type(key, __u32); + __type(value, char[STRSIZE]); +} strdata SEC(".maps"); + +static int __strncmp(const void *m1, const void *m2, size_t len) +{ + const unsigned char *s1 = m1; + const unsigned char *s2 = m2; + int i, delta = 0; + + for (i = 0; i < len; i++) { + delta = s1[i] - s2[i]; + if (delta || s1[i] == 0 || s2[i] == 0) + break; + } + return delta; +} + +#if __has_builtin(__builtin_btf_type_id) +#define TEST_BTF(_str, _type, _flags, _expected, ...) \ + do { \ + static const char _expectedval[EXPECTED_STRSIZE] = \ + _expected; \ + static const char _ptrtype[64] = #_type; \ + __u64 _hflags = _flags | BTF_F_COMPACT; \ + static _type _ptrdata = __VA_ARGS__; \ + static struct btf_ptr _ptr = { }; \ + int _cmp; \ + \ + ++num_subtests; \ + if (ret < 0) \ + break; \ + ++ran_subtests; \ + _ptr.ptr = &_ptrdata; \ + _ptr.type_id = bpf_core_type_id_kernel(_type); \ + if (_ptr.type_id <= 0) { \ + ret = -EINVAL; \ + break; \ + } \ + ret = bpf_snprintf_btf(_str, STRSIZE, \ + &_ptr, sizeof(_ptr), _hflags); \ + if (ret) \ + break; \ + _cmp = __strncmp(_str, _expectedval, EXPECTED_STRSIZE); \ + if (_cmp != 0) { \ + bpf_printk("(%d) got %s", _cmp, _str); \ + bpf_printk("(%d) expected %s", _cmp, \ + _expectedval); \ + ret = -EBADMSG; \ + break; \ + } \ + } while (0) +#endif + +/* Use where expected data string matches its stringified declaration */ +#define TEST_BTF_C(_str, _type, _flags, ...) \ + TEST_BTF(_str, _type, _flags, "(" #_type ")" #__VA_ARGS__, \ + __VA_ARGS__) + +/* TRACE_EVENT(netif_receive_skb, + * TP_PROTO(struct sk_buff *skb), + */ +SEC("tp_btf/netif_receive_skb") +int BPF_PROG(trace_netif_receive_skb, struct sk_buff *skb) +{ + static __u64 flags[] = { 0, BTF_F_COMPACT, BTF_F_ZERO, BTF_F_PTR_RAW, + BTF_F_NONAME, BTF_F_COMPACT | BTF_F_ZERO | + BTF_F_PTR_RAW | BTF_F_NONAME }; + static struct btf_ptr p = { }; + __u32 key = 0; + int i, __ret; + char *str; + +#if __has_builtin(__builtin_btf_type_id) + str = bpf_map_lookup_elem(&strdata, &key); + if (!str) + return 0; + + /* Ensure we can write skb string representation */ + p.type_id = bpf_core_type_id_kernel(struct sk_buff); + p.ptr = skb; + for (i = 0; i < ARRAY_SIZE(flags); i++) { + ++num_subtests; + ret = bpf_snprintf_btf(str, STRSIZE, &p, sizeof(p), 0); + if (ret < 0) + bpf_printk("returned %d when writing skb", ret); + ++ran_subtests; + } + + /* Check invalid ptr value */ + p.ptr = 0; + __ret = bpf_snprintf_btf(str, STRSIZE, &p, sizeof(p), 0); + if (__ret >= 0) { + bpf_printk("printing NULL should generate error, got (%d)", + __ret); + ret = -ERANGE; + } + + /* Verify type display for various types. */ + + /* simple int */ + TEST_BTF_C(str, int, 0, 1234); + TEST_BTF(str, int, BTF_F_NONAME, "1234", 1234); + /* zero value should be printed at toplevel */ + TEST_BTF(str, int, 0, "(int)0", 0); + TEST_BTF(str, int, BTF_F_NONAME, "0", 0); + TEST_BTF(str, int, BTF_F_ZERO, "(int)0", 0); + TEST_BTF(str, int, BTF_F_NONAME | BTF_F_ZERO, "0", 0); + TEST_BTF_C(str, int, 0, -4567); + TEST_BTF(str, int, BTF_F_NONAME, "-4567", -4567); + + /* simple char */ + TEST_BTF_C(str, char, 0, 100); + TEST_BTF(str, char, BTF_F_NONAME, "100", 100); + /* zero value should be printed at toplevel */ + TEST_BTF(str, char, 0, "(char)0", 0); + TEST_BTF(str, char, BTF_F_NONAME, "0", 0); + TEST_BTF(str, char, BTF_F_ZERO, "(char)0", 0); + TEST_BTF(str, char, BTF_F_NONAME | BTF_F_ZERO, "0", 0); + + /* simple typedef */ + TEST_BTF_C(str, uint64_t, 0, 100); + TEST_BTF(str, u64, BTF_F_NONAME, "1", 1); + /* zero value should be printed at toplevel */ + TEST_BTF(str, u64, 0, "(u64)0", 0); + TEST_BTF(str, u64, BTF_F_NONAME, "0", 0); + TEST_BTF(str, u64, BTF_F_ZERO, "(u64)0", 0); + TEST_BTF(str, u64, BTF_F_NONAME|BTF_F_ZERO, "0", 0); + + /* typedef struct */ + TEST_BTF_C(str, atomic_t, 0, {.counter = (int)1,}); + TEST_BTF(str, atomic_t, BTF_F_NONAME, "{1,}", {.counter = 1,}); + /* typedef with 0 value should be printed at toplevel */ + TEST_BTF(str, atomic_t, 0, "(atomic_t){}", {.counter = 0,}); + TEST_BTF(str, atomic_t, BTF_F_NONAME, "{}", {.counter = 0,}); + TEST_BTF(str, atomic_t, BTF_F_ZERO, "(atomic_t){.counter = (int)0,}", + {.counter = 0,}); + TEST_BTF(str, atomic_t, BTF_F_NONAME|BTF_F_ZERO, + "{0,}", {.counter = 0,}); + + /* enum where enum value does (and does not) exist */ + TEST_BTF_C(str, enum bpf_cmd, 0, BPF_MAP_CREATE); + TEST_BTF(str, enum bpf_cmd, 0, "(enum bpf_cmd)BPF_MAP_CREATE", 0); + TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME, "BPF_MAP_CREATE", + BPF_MAP_CREATE); + TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME|BTF_F_ZERO, + "BPF_MAP_CREATE", 0); + + TEST_BTF(str, enum bpf_cmd, BTF_F_ZERO, "(enum bpf_cmd)BPF_MAP_CREATE", + BPF_MAP_CREATE); + TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME|BTF_F_ZERO, + "BPF_MAP_CREATE", BPF_MAP_CREATE); + TEST_BTF_C(str, enum bpf_cmd, 0, 2000); + TEST_BTF(str, enum bpf_cmd, BTF_F_NONAME, "2000", 2000); + + /* simple struct */ + TEST_BTF_C(str, struct btf_enum, 0, + {.name_off = (__u32)3,.val = (__s32)-1,}); + TEST_BTF(str, struct btf_enum, BTF_F_NONAME, "{3,-1,}", + { .name_off = 3, .val = -1,}); + TEST_BTF(str, struct btf_enum, BTF_F_NONAME, "{-1,}", + { .name_off = 0, .val = -1,}); + TEST_BTF(str, struct btf_enum, BTF_F_NONAME|BTF_F_ZERO, "{0,-1,}", + { .name_off = 0, .val = -1,}); + /* empty struct should be printed */ + TEST_BTF(str, struct btf_enum, 0, "(struct btf_enum){}", + { .name_off = 0, .val = 0,}); + TEST_BTF(str, struct btf_enum, BTF_F_NONAME, "{}", + { .name_off = 0, .val = 0,}); + TEST_BTF(str, struct btf_enum, BTF_F_ZERO, + "(struct btf_enum){.name_off = (__u32)0,.val = (__s32)0,}", + { .name_off = 0, .val = 0,}); + + /* struct with pointers */ + TEST_BTF(str, struct list_head, BTF_F_PTR_RAW, + "(struct list_head){.next = (struct list_head *)0x0000000000000001,}", + { .next = (struct list_head *)1 }); + /* NULL pointer should not be displayed */ + TEST_BTF(str, struct list_head, BTF_F_PTR_RAW, + "(struct list_head){}", + { .next = (struct list_head *)0 }); + + /* struct with char array */ + TEST_BTF(str, struct bpf_prog_info, 0, + "(struct bpf_prog_info){.name = (char[])['f','o','o',],}", + { .name = "foo",}); + TEST_BTF(str, struct bpf_prog_info, BTF_F_NONAME, + "{['f','o','o',],}", + {.name = "foo",}); + /* leading null char means do not display string */ + TEST_BTF(str, struct bpf_prog_info, 0, + "(struct bpf_prog_info){}", + {.name = {'\0', 'f', 'o', 'o'}}); + /* handle non-printable characters */ + TEST_BTF(str, struct bpf_prog_info, 0, + "(struct bpf_prog_info){.name = (char[])[1,2,3,],}", + { .name = {1, 2, 3, 0}}); + + /* struct with non-char array */ + TEST_BTF(str, struct __sk_buff, 0, + "(struct __sk_buff){.cb = (__u32[])[1,2,3,4,5,],}", + { .cb = {1, 2, 3, 4, 5,},}); + TEST_BTF(str, struct __sk_buff, BTF_F_NONAME, + "{[1,2,3,4,5,],}", + { .cb = { 1, 2, 3, 4, 5},}); + /* For non-char, arrays, show non-zero values only */ + TEST_BTF(str, struct __sk_buff, 0, + "(struct __sk_buff){.cb = (__u32[])[1,],}", + { .cb = { 0, 0, 1, 0, 0},}); + + /* struct with bitfields */ + TEST_BTF_C(str, struct bpf_insn, 0, + {.code = (__u8)1,.dst_reg = (__u8)0x2,.src_reg = (__u8)0x3,.off = (__s16)4,.imm = (__s32)5,}); + TEST_BTF(str, struct bpf_insn, BTF_F_NONAME, "{1,0x2,0x3,4,5,}", + {.code = 1, .dst_reg = 0x2, .src_reg = 0x3, .off = 4, + .imm = 5,}); +#else + skip = true; +#endif + + return 0; +} + +char _license[] SEC("license") = "GPL";