bpftool: Remove usage of reallocarray()

This commit fixes a compilation error on systems with glibc < 2.26 [0]:

```
In file included from main.h:14:0,
                 from gen.c:24:
linux/tools/include/tools/libc_compat.h:11:21: error: attempt to use poisoned "reallocarray"
 static inline void *reallocarray(void *ptr, size_t nmemb, size_t size)
```

This happens because gen.c pulls <bpf/libbpf_internal.h>, and then
<tools/libc_compat.h> (through main.h). When
COMPAT_NEED_REALLOCARRAY is set, libc_compat.h defines reallocarray()
which libbpf_internal.h poisons with a GCC pragma.

This commit reuses libbpf_reallocarray() implemented in commit
029258d7b228 ("libbpf: Remove any use of reallocarray() in libbpf").

v1 -> v2:
- reuse libbpf_reallocarray() instead of reimplementing it

Fixes: a9caaba399f9 ("bpftool: Implement "gen min_core_btf" logic")
Reported-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Mauricio Vásquez <mauricio@kinvolk.io>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220221125617.39610-1-mauricio@kinvolk.io

[0]: https://lore.kernel.org/bpf/3bf2bd49-9f2d-a2df-5536-bc0dde70a83b@isovalent.com/

1 files changed, 3 insertions, 2 deletions

diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c
index f1f32e21d5cd..2d9cd6a7b3c8 100644
--- a/tools/bpf/bpftool/xlated_dumper.c
+++ b/tools/bpf/bpftool/xlated_dumper.c
@@ -8,6 +8,7 @@
 #include <string.h>
 #include <sys/types.h>
 #include <bpf/libbpf.h>
+#include <bpf/libbpf_internal.h>
 
 #include "disasm.h"
 #include "json_writer.h"
@@ -32,8 +33,8 @@ void kernel_syms_load(struct dump_data *dd)
 		return;
 
 	while (fgets(buff, sizeof(buff), fp)) {
-		tmp = reallocarray(dd->sym_mapping, dd->sym_count + 1,
-				   sizeof(*dd->sym_mapping));
+		tmp = libbpf_reallocarray(dd->sym_mapping, dd->sym_count + 1,
+					  sizeof(*dd->sym_mapping));
 		if (!tmp) {
 out:
 			free(dd->sym_mapping);