b3c09fdca1
Copy libbpf_strlcpy() from libbpf_internal.h to bpf_util.h, and rename it
to bpf_strlcpy(), then replace selftests strncpy()/libbpf_strlcpy() with
bpf_strlcpy(), fix compile warning.
The libbpf_internal.h header cannot be used directly here, because
references to cgroup_helpers.c in samples/bpf will generate compilation
errors. We also can't add libbpf_strlcpy() directly to bpf_util.h,
because the definition of libbpf_strlcpy() in libbpf_internal.h is
duplicated. In order not to modify the libbpf code, add a new function
bpf_strlcpy() to selftests bpf_util.h.
How to reproduce this compilation warning:
$ make -C samples/bpf
cgroup_helpers.c: In function ‘__enable_controllers’:
cgroup_helpers.c:80:17: warning: ‘strncpy’ specified bound 4097 equals destination size [-Wstringop-truncation]
80 | strncpy(enable, controllers, sizeof(enable));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Rong Tao <rongtao@cestc.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/tencent_469D8AF32BD56816A29981BED06E96D22506@qq.com
63 lines
1.6 KiB
C
63 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __BPF_UTIL__
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#define __BPF_UTIL__
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <bpf/libbpf.h> /* libbpf_num_possible_cpus */
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static inline unsigned int bpf_num_possible_cpus(void)
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{
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int possible_cpus = libbpf_num_possible_cpus();
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if (possible_cpus < 0) {
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printf("Failed to get # of possible cpus: '%s'!\n",
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strerror(-possible_cpus));
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exit(1);
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}
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return possible_cpus;
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}
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/* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst
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* is zero-terminated string no matter what (unless sz == 0, in which case
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* it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs
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* in what is returned. Given this is internal helper, it's trivial to extend
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* this, when necessary. Use this instead of strncpy inside libbpf source code.
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*/
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static inline void bpf_strlcpy(char *dst, const char *src, size_t sz)
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{
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size_t i;
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if (sz == 0)
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return;
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sz--;
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for (i = 0; i < sz && src[i]; i++)
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dst[i] = src[i];
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dst[i] = '\0';
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}
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#define __bpf_percpu_val_align __attribute__((__aligned__(8)))
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#define BPF_DECLARE_PERCPU(type, name) \
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struct { type v; /* padding */ } __bpf_percpu_val_align \
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name[bpf_num_possible_cpus()]
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#define bpf_percpu(name, cpu) name[(cpu)].v
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#ifndef ARRAY_SIZE
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# define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
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#endif
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#ifndef sizeof_field
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#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
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#endif
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#ifndef offsetofend
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#define offsetofend(TYPE, MEMBER) \
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(offsetof(TYPE, MEMBER) + sizeof_field(TYPE, MEMBER))
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#endif
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#endif /* __BPF_UTIL__ */
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