xref: /linux/tools/testing/selftests/bpf/bpf_util.h (revision 57885276cc16a2e2b76282c808a4e84cbecb3aae)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __BPF_UTIL__
3 #define __BPF_UTIL__
4 
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <string.h>
8 #include <errno.h>
9 #include <syscall.h>
10 #include <bpf/libbpf.h> /* libbpf_num_possible_cpus */
11 #include <linux/args.h>
12 
13 static inline unsigned int bpf_num_possible_cpus(void)
14 {
15 	int possible_cpus = libbpf_num_possible_cpus();
16 
17 	if (possible_cpus < 0) {
18 		printf("Failed to get # of possible cpus: '%s'!\n",
19 		       strerror(-possible_cpus));
20 		exit(1);
21 	}
22 	return possible_cpus;
23 }
24 
25 /*
26  * Simplified strscpy() implementation. The kernel one is in lib/string.c
27  */
28 static inline ssize_t sized_strscpy(char *dest, const char *src, size_t count)
29 {
30 	long res = 0;
31 
32 	if (count == 0)
33 		return -E2BIG;
34 
35 	while (count > 1) {
36 		char c;
37 
38 		c = src[res];
39 		dest[res] = c;
40 		if (!c)
41 			return res;
42 		res++;
43 		count--;
44 	}
45 
46 	/* Force NUL-termination. */
47 	dest[res] = '\0';
48 
49 	/* Return E2BIG if the source didn't stop */
50 	return src[res] ? -E2BIG : res;
51 }
52 
53 #define __strscpy0(dst, src, ...)	\
54 	sized_strscpy(dst, src, sizeof(dst))
55 #define __strscpy1(dst, src, size)	\
56 	sized_strscpy(dst, src, size)
57 
58 #undef strscpy /* Redefine the placeholder from tools/include/linux/string.h */
59 #define strscpy(dst, src, ...)	\
60 	CONCATENATE(__strscpy, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)
61 
62 #define __bpf_percpu_val_align	__attribute__((__aligned__(8)))
63 
64 #define BPF_DECLARE_PERCPU(type, name)				\
65 	struct { type v; /* padding */ } __bpf_percpu_val_align	\
66 		name[bpf_num_possible_cpus()]
67 #define bpf_percpu(name, cpu) name[(cpu)].v
68 
69 #ifndef ARRAY_SIZE
70 # define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
71 #endif
72 
73 #ifndef sizeof_field
74 #define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
75 #endif
76 
77 #ifndef offsetofend
78 #define offsetofend(TYPE, MEMBER) \
79 	(offsetof(TYPE, MEMBER)	+ sizeof_field(TYPE, MEMBER))
80 #endif
81 
82 /* Availability of gettid across glibc versions is hit-and-miss, therefore
83  * fallback to syscall in this macro and use it everywhere.
84  */
85 #ifndef sys_gettid
86 #define sys_gettid() syscall(SYS_gettid)
87 #endif
88 
89 /* and poison usage to ensure it does not creep back in. */
90 #pragma GCC poison gettid
91 
92 #ifndef ENOTSUPP
93 #define ENOTSUPP 524
94 #endif
95 
96 #endif /* __BPF_UTIL__ */
97