From 2c6f445a8ea43686d20d08c2fc3c9f2d16ff0973 Mon Sep 17 00:00:00 2001 From: Quentin Deslandes Date: Sat, 13 Apr 2024 23:12:57 +0200 Subject: [PATCH] libbpf: Fix misaligned array closing bracket In btf_dump_array_data(), libbpf will call btf_dump_dump_type_data() for each element. For an array of characters, each element will be processed the following way: - btf_dump_dump_type_data() is called to print the character - btf_dump_data_pfx() prefixes the current line with the proper number of indentations - btf_dump_int_data() is called to print the character - After the last character is printed, btf_dump_dump_type_data() calls btf_dump_data_pfx() before writing the closing bracket However, for an array containing characters, btf_dump_int_data() won't print any '\0' and subsequent characters. This leads to situations where the line prefix is written, no character is added, then the prefix is written again before adding the closing bracket: (struct sk_metadata){ .str_array = (__u8[14])[ 'H', 'e', 'l', 'l', 'o', ], This change solves this issue by printing the '\0' character, which has two benefits: - The bracket closing the array is properly aligned - It's clear from a user point of view that libbpf uses '\0' as a terminator for arrays of characters. Signed-off-by: Quentin Deslandes Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20240413211258.134421-2-qde@naccy.de --- src/btf_dump.c | 1 + 1 file changed, 1 insertion(+) diff --git a/src/btf_dump.c b/src/btf_dump.c index 4d9f30b..6a37e85 100644 --- a/src/btf_dump.c +++ b/src/btf_dump.c @@ -1929,6 +1929,7 @@ static int btf_dump_int_data(struct btf_dump *d, if (d->typed_dump->is_array_terminated) break; if (*(char *)data == '\0') { + btf_dump_type_values(d, "'\\0'"); d->typed_dump->is_array_terminated = true; break; }