From daa1284af3b9a8d73b1dadaa12bc4068a4ce22ab Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Tue, 21 Aug 2018 12:20:06 -0300 Subject: [PATCH] perf trace: Augment the 'open' syscall 'filename' arg As described in the previous cset, all we had to do was to touch the augmented_syscalls.c eBPF program, fire up 'perf trace' with that new eBPF script in system wide mode and wait for 'open' syscalls, in addition to 'openat' ones to see that it works: # perf trace -e tools/perf/examples/bpf/augmented_syscalls.c 0.000 StreamT~s #200/16150 openat(dfd: CWD, filename: /home/acme/.mozilla/firefox/fqxhj76d.default/prefs.js, flags: CREAT|EXCL|TRUNC|WRONLY, mode: IRUSR|IWUSR) 0.065 StreamT~s #200/16150 openat(dfd: CWD, filename: /home/acme/.mozilla/firefox/fqxhj76d.default/prefs-1.js, flags: CREAT|EXCL|TRUNC|WRONLY, mode: IRUSR|IWUSR) 0.435 StreamT~s #200/16150 openat(dfd: CWD, filename: /home/acme/.mozilla/firefox/fqxhj76d.default/prefs-1.js, flags: CREAT|TRUNC|WRONLY, mode: IRUSR|IWUSR) 1.875 perf/16772 openat(dfd: CWD, filename: /sys/kernel/debug/tracing/events/syscalls/sys_enter_openat/form) 1227.260 gnome-shell/1463 openat(dfd: CWD, filename: /proc/self/stat) 1227.397 gnome-shell/2125 openat(dfd: CWD, filename: /proc/self/stat) 7227.619 gnome-shell/1463 openat(dfd: CWD, filename: /proc/self/stat) 7227.661 gnome-shell/2125 openat(dfd: CWD, filename: /proc/self/stat) 10018.079 gnome-shell/1463 openat(dfd: CWD, filename: /proc/self/stat) 10018.514 perf/16772 openat(dfd: CWD, filename: /proc/1237/status) 10018.568 perf/16772 openat(dfd: CWD, filename: /proc/1237/status) 10022.409 gnome-shell/2125 openat(dfd: CWD, filename: /proc/self/stat) 10090.044 NetworkManager/1237 openat(dfd: CWD, filename: /proc/2125/stat) 10090.351 NetworkManager/1237 open(filename: /etc/passwd, flags: CLOEXEC) 10090.407 perf/16772 openat(dfd: CWD, filename: /sys/kernel/debug/tracing/events/syscalls/sys_enter_open/format) 10091.763 NetworkManager/1237 openat(dfd: CWD, filename: /proc/2125/stat) 10091.812 NetworkManager/1237 open(filename: /etc/passwd, flags: CLOEXEC) 10092.807 NetworkManager/1237 openat(dfd: CWD, filename: /proc/2125/stat) 10092.851 NetworkManager/1237 open(filename: /etc/passwd, flags: CLOEXEC) 10094.650 NetworkManager/1237 openat(dfd: CWD, filename: /proc/1463/stat) 10094.926 NetworkManager/1237 open(filename: /etc/passwd, flags: CLOEXEC) 10096.010 NetworkManager/1237 openat(dfd: CWD, filename: /proc/1463/stat) 10096.057 NetworkManager/1237 open(filename: /etc/passwd, flags: CLOEXEC) 10097.056 NetworkManager/1237 openat(dfd: CWD, filename: /proc/1463/stat) 10097.099 NetworkManager/1237 open(filename: /etc/passwd, flags: CLOEXEC) 13228.345 gnome-shell/1463 openat(dfd: CWD, filename: /proc/self/stat) 13232.734 gnome-shell/2125 openat(dfd: CWD, filename: /proc/self/stat) 15198.956 lighttpd/16748 open(filename: /proc/loadavg, mode: ISGID|IXOTH) ^C# It even catches 'perf' itself looking at the sys_enter_open and sys_enter_openat tracefs format dictionaries when it first finds them in the trace... :-) Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: https://lkml.kernel.org/n/tip-upmogc57uatljr6el6u8537l@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/examples/bpf/augmented_syscalls.c | 27 ++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/tools/perf/examples/bpf/augmented_syscalls.c b/tools/perf/examples/bpf/augmented_syscalls.c index 93960e891478..154379463c95 100644 --- a/tools/perf/examples/bpf/augmented_syscalls.c +++ b/tools/perf/examples/bpf/augmented_syscalls.c @@ -61,4 +61,31 @@ int syscall_enter(openat)(struct syscall_enter_openat_args *args) return 0; } +struct syscall_enter_open_args { + unsigned long long common_tp_fields; + long syscall_nr; + char *filename_ptr; + long flags; + long mode; +}; + +struct augmented_enter_open_args { + struct syscall_enter_open_args args; + struct augmented_filename filename; +}; + +int syscall_enter(open)(struct syscall_enter_open_args *args) +{ + struct augmented_enter_open_args augmented_args = { .filename.reserved = 0, }; + + probe_read(&augmented_args.args, sizeof(augmented_args.args), args); + augmented_args.filename.size = probe_read_str(&augmented_args.filename.value, + sizeof(augmented_args.filename.value), + args->filename_ptr); + perf_event_output(args, &__augmented_syscalls__, BPF_F_CURRENT_CPU, + &augmented_args, + sizeof(augmented_args) - sizeof(augmented_args.filename.value) + augmented_args.filename.size); + return 0; +} + license(GPL); -- 2.30.2