Yonghong Song 73df93c57c tools/bpftool: fix a bug in bpftool perf ... Commit b04df400c3 ("tools/bpftool: add perf subcommand") introduced bpftool subcommand perf to query bpf program kuprobe and tracepoint attachments. The perf subcommand will first test whether bpf subcommand BPF_TASK_FD_QUERY is supported in kernel or not. It does it by opening a file with argv[0] and feeds the file descriptor and current task pid to the kernel for querying. Such an approach won't work if the argv[0] cannot be opened successfully in the current directory. This is especially true when bpftool is accessible through PATH env variable. The error below reflects the open failure for file argv[0] at home directory. [yhs@localhost ~]$ which bpftool /usr/local/sbin/bpftool [yhs@localhost ~]$ bpftool perf Error: perf_query_support: No such file or directory To fix the issue, let us open root directory ("/") which exists in every linux system. With the fix, the error message will correctly reflect the permission issue. [yhs@localhost ~]$ which bpftool /usr/local/sbin/bpftool [yhs@localhost ~]$ bpftool perf Error: perf_query_support: Operation not permitted HINT: non root or kernel doesn't support TASK_FD_QUERY Fixes: b04df400c3 ("tools/bpftool: add perf subcommand") Reported-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>		2018-06-13 02:03:17 +02:00
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bpftool	tools/bpftool: fix a bug in bpftool perf	2018-06-13 02:03:17 +02:00
bpf_asm.c	tools: rename tools/net directory to tools/bpf	2017-10-04 21:45:05 -07:00
bpf_dbg.c	bpf: fix uninitialized variable in bpf tools	2018-04-26 22:23:02 +02:00
bpf_exp.l	bpf: fix cbpf parser bug for octal numbers	2018-06-03 07:46:55 -07:00
bpf_exp.y	tools: rename tools/net directory to tools/bpf	2017-10-04 21:45:05 -07:00
bpf_jit_disasm.c	tools/bpf_jit_disasm: silence a static checker warning	2018-01-18 22:15:37 +01:00
Makefile	bpf: fix for lex/yacc build error with gcc-5	2018-04-25 23:27:46 +02:00