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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/perf/examples/bpf/etcsnoop.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | tools/perf/examples/bpf/etcsnoop.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/tools/perf/examples/bpf/etcsnoop.c b/tools/perf/examples/bpf/etcsnoop.c new file mode 100644 index 000000000..e81b53534 --- /dev/null +++ b/tools/perf/examples/bpf/etcsnoop.c @@ -0,0 +1,76 @@ +// 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); |