From d55dfe587bc0670f90564a962615723fe7749ab1 Mon Sep 17 00:00:00 2001 From: Manu Bretelle Date: Mon, 1 Aug 2022 06:24:09 -0700 Subject: [PATCH] bpftool: Remove BPF_OBJ_NAME_LEN restriction when looking up bpf program by name bpftool was limiting the length of names to BPF_OBJ_NAME_LEN in prog_parse fds. Since commit b662000aff84 ("bpftool: Adding support for BTF program names") we can get the full program name from BTF. This patch removes the restriction of name length when running `bpftool prog show name ${name}`. Test: Tested against some internal program names that were longer than `BPF_OBJ_NAME_LEN`, here a redacted example of what was ran to test. # previous behaviour $ sudo bpftool prog show name some_long_program_name Error: can't parse name # with the patch $ sudo ./bpftool prog show name some_long_program_name 123456789: tracing name some_long_program_name tag taghexa gpl .... ... ... ... # too long sudo ./bpftool prog show name $(python3 -c 'print("A"*128)') Error: can't parse name # not too long but no match $ sudo ./bpftool prog show name $(python3 -c 'print("A"*127)') Signed-off-by: Manu Bretelle Signed-off-by: Andrii Nakryiko Tested-by: Jiri Olsa Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20220801132409.4147849-1-chantr4@gmail.com --- tools/bpf/bpftool/common.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c index 067e9ea59e3b..8727765add88 100644 --- a/tools/bpf/bpftool/common.c +++ b/tools/bpf/bpftool/common.c @@ -722,6 +722,7 @@ print_all_levels(__maybe_unused enum libbpf_print_level level, static int prog_fd_by_nametag(void *nametag, int **fds, bool tag) { + char prog_name[MAX_PROG_FULL_NAME]; unsigned int id = 0; int fd, nb_fds = 0; void *tmp; @@ -754,12 +755,20 @@ static int prog_fd_by_nametag(void *nametag, int **fds, bool tag) goto err_close_fd; } - if ((tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) || - (!tag && strncmp(nametag, info.name, BPF_OBJ_NAME_LEN))) { + if (tag && memcmp(nametag, info.tag, BPF_TAG_SIZE)) { close(fd); continue; } + if (!tag) { + get_prog_full_name(&info, fd, prog_name, + sizeof(prog_name)); + if (strncmp(nametag, prog_name, sizeof(prog_name))) { + close(fd); + continue; + } + } + if (nb_fds > 0) { tmp = realloc(*fds, (nb_fds + 1) * sizeof(int)); if (!tmp) { @@ -820,7 +829,7 @@ int prog_parse_fds(int *argc, char ***argv, int **fds) NEXT_ARGP(); name = **argv; - if (strlen(name) > BPF_OBJ_NAME_LEN - 1) { + if (strlen(name) > MAX_PROG_FULL_NAME - 1) { p_err("can't parse name"); return -1; }