From: Arnaldo Carvalho de Melo <acme@redhat.com>

Date: Tue, 16 Jul 2019 12:31:10 -0300

Subject: perf augmented_raw_syscalls: Add handler for "openat"

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Git-commit: 236dd5838871024d58d354ff8d0dab00ee59a867

Patch-mainline: v5.4-rc1

References: jsc#SLE-13661

​

I.e. for a syscall that has its second argument being a string, its

difficult these days to find 'open' being used in the wild :-)

​

Cc: Adrian Hunter <adrian.hunter@intel.com>

Cc: Jiri Olsa <jolsa@kernel.org>

Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>

Cc: Namhyung Kim <namhyung@kernel.org>

Link: https://lkml.kernel.org/n/tip-yf3kbzirqrukd3fb2sp5qx4p@git.kernel.org

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Tony Jones <tonyj@suse.de>

---

 tools/perf/builtin-trace.c                       |  1 +

 tools/perf/examples/bpf/augmented_raw_syscalls.c | 17 +++++++++++++++++

 2 files changed, 18 insertions(+)

​

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c

index 872c9cc982a5..a681b8c2ee4e 100644

--- a/tools/perf/builtin-trace.c

+++ b/tools/perf/builtin-trace.c

@@ -836,6 +836,7 @@ static struct syscall_fmt {

      .arg = { [0] = { .scnprintf = SCA_FDAT,   /* dfd */ },

           [2] = { .scnprintf = SCA_OPEN_FLAGS, /* flags */ }, }, },

    { .name     = "openat",

+     .bpf_prog_name = { .sys_enter = "!syscalls:sys_enter_openat", },

      .arg = { [0] = { .scnprintf = SCA_FDAT,   /* dfd */ },

           [2] = { .scnprintf = SCA_OPEN_FLAGS, /* flags */ }, }, },

    { .name     = "perf_event_open",

diff --git a/tools/perf/examples/bpf/augmented_raw_syscalls.c b/tools/perf/examples/bpf/augmented_raw_syscalls.c

index c66474a6ccf4..661936f90fe0 100644

--- a/tools/perf/examples/bpf/augmented_raw_syscalls.c

+++ b/tools/perf/examples/bpf/augmented_raw_syscalls.c

@@ -131,6 +131,23 @@ int sys_enter_open(struct syscall_enter_args *args)

    return perf_event_output(args, &__augmented_syscalls__, BPF_F_CURRENT_CPU, augmented_args, len);

 }

+SEC("!syscalls:sys_enter_openat")

+int sys_enter_openat(struct syscall_enter_args *args)

+{

+   int key = 0;

+   struct augmented_args_filename *augmented_args = bpf_map_lookup_elem(&augmented_filename_map, &key);

+   const void *filename_arg = (const void *)args->args[1];

+   unsigned int len = sizeof(augmented_args->args);

+

+        if (augmented_args == NULL)

+                return 1; /* Failure: don't filter */

+

+   len += augmented_filename__read(&augmented_args->filename, filename_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)

 {

​

​