77 lines
2.6 KiB
C
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);
|