linux_dsm_epyc7002/tools/perf/examples/bpf/etcsnoop.c
Arnaldo Carvalho de Melo f52fdd64f6 perf bpf examples: Convert etcsnoop to use bpf_map()
Making the code more compact, end result is the same:

  # trace -e /home/acme/git/perf/tools/perf/examples/bpf/etcsnoop.c
     0.000 (         ): sed/7385 openat(dfd: CWD, filename: "/etc/ld.so.cache", flags: RDONLY|CLOEXEC) ...
  2727.723 (         ): cat/7389 openat(dfd: CWD, filename: "/etc/ld.so.cache", flags: RDONLY|CLOEXEC) ...
  2728.543 (         ): cat/7389 openat(dfd: CWD, filename: "/etc/passwd")                          ...
  ^C

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>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-znhgz24p0daux2kay200ovc1@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-01-25 15:12:11 +01:00

77 lines
2.6 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Augment the filename syscalls with the contents of the filename pointer argument
* filtering only those that do not start with /etc/.
*
* Test it with:
*
* perf trace -e tools/perf/examples/bpf/augmented_syscalls.c cat /etc/passwd > /dev/null
*
* It'll catch some openat syscalls related to the dynamic linked and
* the last one should be the one for '/etc/passwd'.
*
* This matches what is marshalled into the raw_syscall:sys_enter payload
* expected by the 'perf trace' beautifiers, and can be used by them unmodified,
* which will be done as that feature is implemented in the next csets, for now
* it will appear in a dump done by the default tracepoint handler in 'perf trace',
* that uses bpf_output__fprintf() to just dump those contents, as done with
* the bpf-output event associated with the __bpf_output__ map declared in
* tools/perf/include/bpf/stdio.h.
*/
#include <stdio.h>
/* bpf-output associated map */
bpf_map(__augmented_syscalls__, PERF_EVENT_ARRAY, int, u32, __NR_CPUS__);
struct augmented_filename {
int size;
int reserved;
char value[64];
};
#define augmented_filename_syscall_enter(syscall) \
struct augmented_enter_##syscall##_args { \
struct syscall_enter_##syscall##_args args; \
struct augmented_filename filename; \
}; \
int syscall_enter(syscall)(struct syscall_enter_##syscall##_args *args) \
{ \
char etc[6] = "/etc/"; \
struct augmented_enter_##syscall##_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); \
if (__builtin_memcmp(augmented_args.filename.value, etc, 4) != 0) \
return 0; \
/* 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, \
(sizeof(augmented_args) - sizeof(augmented_args.filename.value) + \
augmented_args.filename.size)); \
}
struct syscall_enter_openat_args {
unsigned long long common_tp_fields;
long syscall_nr;
long dfd;
char *filename_ptr;
long flags;
long mode;
};
augmented_filename_syscall_enter(openat);
struct syscall_enter_open_args {
unsigned long long common_tp_fields;
long syscall_nr;
char *filename_ptr;
long flags;
long mode;
};
augmented_filename_syscall_enter(open);
license(GPL);