1 files changed, 52 insertions, 20 deletions

diff --git a/tools/testing/selftests/bpf/bpf_util.h b/tools/testing/selftests/bpf/bpf_util.h
index 20ecbaa0d85d..4bc2d25f33e1 100644
--- a/tools/testing/selftests/bpf/bpf_util.h
+++ b/tools/testing/selftests/bpf/bpf_util.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __BPF_UTIL__
 #define __BPF_UTIL__
 
@@ -5,34 +6,38 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#include <syscall.h>
+#include <bpf/libbpf.h> /* libbpf_num_possible_cpus */
 
 static inline unsigned int bpf_num_possible_cpus(void)
 {
-	static const char *fcpu = "/sys/devices/system/cpu/possible";
-	unsigned int start, end, possible_cpus = 0;
-	char buff[128];
-	FILE *fp;
-
-	fp = fopen(fcpu, "r");
-	if (!fp) {
-		printf("Failed to open %s: '%s'!\n", fcpu, strerror(errno));
+	int possible_cpus = libbpf_num_possible_cpus();
+
+	if (possible_cpus < 0) {
+		printf("Failed to get # of possible cpus: '%s'!\n",
+		       strerror(-possible_cpus));
 		exit(1);
 	}
+	return possible_cpus;
+}
 
-	while (fgets(buff, sizeof(buff), fp)) {
-		if (sscanf(buff, "%u-%u", &start, &end) == 2) {
-			possible_cpus = start == 0 ? end + 1 : 0;
-			break;
-		}
-	}
+/* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst
+ * is zero-terminated string no matter what (unless sz == 0, in which case
+ * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs
+ * in what is returned. Given this is internal helper, it's trivial to extend
+ * this, when necessary. Use this instead of strncpy inside libbpf source code.
+ */
+static inline void bpf_strlcpy(char *dst, const char *src, size_t sz)
+{
+	size_t i;
 
-	fclose(fp);
-	if (!possible_cpus) {
-		printf("Failed to retrieve # possible CPUs!\n");
-		exit(1);
-	}
+	if (sz == 0)
+		return;
 
-	return possible_cpus;
+	sz--;
+	for (i = 0; i < sz && src[i]; i++)
+		dst[i] = src[i];
+	dst[i] = '\0';
 }
 
 #define __bpf_percpu_val_align	__attribute__((__aligned__(8)))
@@ -42,4 +47,31 @@ static inline unsigned int bpf_num_possible_cpus(void)
 		name[bpf_num_possible_cpus()]
 #define bpf_percpu(name, cpu) name[(cpu)].v
 
+#ifndef ARRAY_SIZE
+# define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#endif
+
+#ifndef sizeof_field
+#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
+#endif
+
+#ifndef offsetofend
+#define offsetofend(TYPE, MEMBER) \
+	(offsetof(TYPE, MEMBER)	+ sizeof_field(TYPE, MEMBER))
+#endif
+
+/* Availability of gettid across glibc versions is hit-and-miss, therefore
+ * fallback to syscall in this macro and use it everywhere.
+ */
+#ifndef sys_gettid
+#define sys_gettid() syscall(SYS_gettid)
+#endif
+
+/* and poison usage to ensure it does not creep back in. */
+#pragma GCC poison gettid
+
+#ifndef ENOTSUPP
+#define ENOTSUPP 524
+#endif
+
 #endif /* __BPF_UTIL__ */