From: Arnaldo Carvalho de Melo <a...@redhat.com> Starting with the renameat and renameat2 syscall, that both receive as second and fourth parameters a pathname:
# perf trace -e rename* mv one ANOTHER LLVM: dumping /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o mv: cannot stat 'one': No such file or directory renameat2(AT_FDCWD, "one", AT_FDCWD, "ANOTHER", RENAME_NOREPLACE) = -1 ENOENT (No such file or directory) # Since the per CPU scratch buffer map has space for two maximum sized pathnames, the verifier is satisfied that there will be no overrun. Cc: Adrian Hunter <adrian.hun...@intel.com> Cc: Jiri Olsa <jo...@kernel.org> Cc: Luis Cláudio Gonçalves <lclau...@redhat.com> Cc: Namhyung Kim <namhy...@kernel.org> Link: https://lkml.kernel.org/n/tip-x2uboyg5kx2wqeru28820...@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/builtin-trace.c | 2 ++ .../examples/bpf/augmented_raw_syscalls.c | 20 +++++++++++++++++++ 2 files changed, 22 insertions(+) diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index a681b8c2ee4e..c64f7c99db15 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -873,9 +873,11 @@ static struct syscall_fmt { { .name = "recvmsg", .arg = { [2] = { .scnprintf = SCA_MSG_FLAGS, /* flags */ }, }, }, { .name = "renameat", + .bpf_prog_name = { .sys_enter = "!syscalls:sys_enter_renameat", }, .arg = { [0] = { .scnprintf = SCA_FDAT, /* olddirfd */ }, [2] = { .scnprintf = SCA_FDAT, /* newdirfd */ }, }, }, { .name = "renameat2", + .bpf_prog_name = { .sys_enter = "!syscalls:sys_enter_renameat", }, .arg = { [0] = { .scnprintf = SCA_FDAT, /* olddirfd */ }, [2] = { .scnprintf = SCA_FDAT, /* newdirfd */ }, [4] = { .scnprintf = SCA_RENAMEAT2_FLAGS, /* flags */ }, }, }, diff --git a/tools/perf/examples/bpf/augmented_raw_syscalls.c b/tools/perf/examples/bpf/augmented_raw_syscalls.c index ce308b9a317c..df52d92e1c69 100644 --- a/tools/perf/examples/bpf/augmented_raw_syscalls.c +++ b/tools/perf/examples/bpf/augmented_raw_syscalls.c @@ -70,6 +70,7 @@ pid_filter(pids_filtered); struct augmented_args_filename { struct syscall_enter_args args; struct augmented_filename filename; + struct augmented_filename filename2; }; bpf_map(augmented_filename_map, PERCPU_ARRAY, int, struct augmented_args_filename, 1); @@ -148,6 +149,25 @@ int sys_enter_openat(struct syscall_enter_args *args) return perf_event_output(args, &__augmented_syscalls__, BPF_F_CURRENT_CPU, augmented_args, len); } +SEC("!syscalls:sys_enter_renameat") +int sys_enter_renameat(struct syscall_enter_args *args) +{ + int key = 0; + struct augmented_args_filename *augmented_args = bpf_map_lookup_elem(&augmented_filename_map, &key); + const void *oldpath_arg = (const void *)args->args[1], + *newpath_arg = (const void *)args->args[3]; + unsigned int len = sizeof(augmented_args->args), oldpath_len; + + if (augmented_args == NULL) + return 1; /* Failure: don't filter */ + + oldpath_len = augmented_filename__read(&augmented_args->filename, oldpath_arg, sizeof(augmented_args->filename.value)); + len += oldpath_len + augmented_filename__read((void *)(&augmented_args->filename) + oldpath_len, newpath_arg, sizeof(augmented_args->filename.value)); + + /* If perf_event_output fails, return non-zero so that it gets recorded unaugmented */ + return perf_event_output(args, &__augmented_syscalls__, BPF_F_CURRENT_CPU, augmented_args, len); +} + SEC("raw_syscalls:sys_enter") int sys_enter(struct syscall_enter_args *args) { -- 2.21.0
