libbpf: Centralize poisoning and poison reallocarray()

Most of libbpf source files already include libbpf_internal.h, so it's a good
place to centralize identifier poisoning. So move kernel integer type
poisoning there. And also add reallocarray to a poison list to prevent
accidental use of it. libbpf_reallocarray() should be used universally
instead.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200819013607.3607269-4-andriin@fb.com

tools/lib/bpf/bpf.c

@@ -32,9 +32,6 @@
 #include "libbpf.h"
 #include "libbpf_internal.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 /*
  * When building perf, unistd.h is overridden. __NR_bpf is
  * required to be defined explicitly.

tools/lib/bpf/bpf_prog_linfo.c

@@ -8,9 +8,6 @@
 #include "libbpf.h"
 #include "libbpf_internal.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 struct bpf_prog_linfo {
 	void *raw_linfo;
 	void *raw_jited_linfo;

tools/lib/bpf/btf.c

@@ -21,9 +21,6 @@
 #include "libbpf_internal.h"
 #include "hashmap.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 #define BTF_MAX_NR_TYPES 0x7fffffffU
 #define BTF_MAX_STR_OFFSET 0x7fffffffU
 

tools/lib/bpf/btf_dump.c

@@ -19,9 +19,6 @@
 #include "libbpf.h"
 #include "libbpf_internal.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 static const char PREFIXES[] = "\t\t\t\t\t\t\t\t\t\t\t\t\t";
 static const size_t PREFIX_CNT = sizeof(PREFIXES) - 1;
 

tools/lib/bpf/hashmap.c

@@ -15,6 +15,9 @@
 /* make sure libbpf doesn't use kernel-only integer typedefs */
 #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
 
+/* prevent accidental re-addition of reallocarray() */
+#pragma GCC poison reallocarray
+
 /* start with 4 buckets */
 #define HASHMAP_MIN_CAP_BITS 2
 

tools/lib/bpf/libbpf.c

@@ -55,9 +55,6 @@
 #include "libbpf_internal.h"
 #include "hashmap.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 #ifndef EM_BPF
 #define EM_BPF 247
 #endif

tools/lib/bpf/libbpf_internal.h

@@ -10,6 +10,13 @@
 #define __LIBBPF_LIBBPF_INTERNAL_H
 
 #include <stdlib.h>
+
+/* make sure libbpf doesn't use kernel-only integer typedefs */
+#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
+
+/* prevent accidental re-addition of reallocarray() */
+#pragma GCC poison reallocarray
+
 #include "libbpf.h"
 
 #define BTF_INFO_ENC(kind, kind_flag, vlen) \

tools/lib/bpf/libbpf_probes.c

@@ -17,9 +17,6 @@
 #include "libbpf.h"
 #include "libbpf_internal.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 static bool grep(const char *buffer, const char *pattern)
 {
 	return !!strstr(buffer, pattern);

tools/lib/bpf/netlink.c

@@ -15,9 +15,6 @@
 #include "libbpf_internal.h"
 #include "nlattr.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 #ifndef SOL_NETLINK
 #define SOL_NETLINK 270
 #endif

tools/lib/bpf/nlattr.c

@@ -7,14 +7,11 @@
  */
 
 #include <errno.h>
-#include "nlattr.h"
-#include "libbpf_internal.h"
-#include <linux/rtnetlink.h>
 #include <string.h>
 #include <stdio.h>
-
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
+#include <linux/rtnetlink.h>
+#include "nlattr.h"
+#include "libbpf_internal.h"
 
 static uint16_t nla_attr_minlen[LIBBPF_NLA_TYPE_MAX+1] = {
 	[LIBBPF_NLA_U8]		= sizeof(uint8_t),

tools/lib/bpf/ringbuf.c

@@ -21,9 +21,6 @@
 #include "libbpf_internal.h"
 #include "bpf.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 struct ring {
 	ring_buffer_sample_fn sample_cb;
 	void *ctx;

tools/lib/bpf/xsk.c

@@ -32,9 +32,6 @@
 #include "libbpf_internal.h"
 #include "xsk.h"
 
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
 #ifndef SOL_XDP
  #define SOL_XDP 283
 #endif