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#!/usr/bin/env raku
use v6.d;
# Grammar to parse /sys/kernel/tracing/events/syscalls/sys_{enter,exit}_*/format'
grammar SysTraceFormat {
rule TOP { <whole-format-section>* }
rule whole-format-section { <name> <id> <format> <print-fmt> }
rule name { 'name:' <identifier> }
rule id { 'ID:' <number> }
rule format { 'format:' <field>* }
rule field { 'field:' <field-elements> }
rule field-elements { <field-declaration> <field-offset> <field-size> <field-signed> }
rule field-declaration { <field-type>+ <identifier> ';' }
token field-type { <-[ \t]> }
token field-offset { 'offset:' <number> ';' }
token field-size { 'size:' <number> ';' }
token field-signed { 'signed:' <cbool> ';' }
token identifier { <[a..zA..Z0..9_]>+ }
token number { \d+ }
token cbool { '0' | '1' }
token print-fmt { 'print fmt' <-[\n]>+ "\n" }
}
class Field {
has Str $.type is rw;
has Str $.name is rw;
has Int $.offset is rw;
has Int $.size is rw;
has Bool $.signed is rw;
}
role TracepointTemplate {
method template(%vals --> Str) {
my Bool \is-enter = %vals<name>.split('_')[1] eq 'enter';
my Str \ctx-struct = is-enter ?? 'trace_event_raw_sys_enter' !! 'trace_event_raw_sys_exit';
my Str @parts;
@parts.push: qq:to/BPF_C_CODE/;
SEC("tracepoint/syscalls/{%vals<name>}")
int handle_{%vals<name>.lc}(struct {ctx-struct} *ctx) \{
__u32 pid, tid;
if (filter(&pid, &tid))
return 0;
struct {%vals<event-struct>} *ev = bpf_ringbuf_reserve(&event_map, sizeof(struct {%vals<event-struct>}), 0);
if (!ev)
return 0;
ev->event_type = {(is-enter ?? 'ENTER_' !! 'EXIT_') ~ %vals<event-struct>.uc};
ev->trace_id = {%vals<name>.uc};
ev->pid = pid;
ev->tid = tid;
ev->time = bpf_ktime_get_boot_ns();
BPF_C_CODE
@parts.push: %vals<extra> if %vals<extra>:exists;
@parts.push: qq:to/BPF_C_CODE/;
bpf_ringbuf_submit(ev, 0);
return 0;
\}
BPF_C_CODE
[~] @parts;
}
}
class FdTracepoint does TracepointTemplate {
method generate-bpf-c-tracepoint(%vals --> Str) {
my Str $extra = qq:to/BPF_C_CODE/;
ev->fd = (__s32)ctx->args[0];
BPF_C_CODE
self.template: %vals.append( ( event-struct => 'fd_event', :$extra ).hash );
}
}
class NameTracepoint does TracepointTemplate {
method generate-bpf-c-tracepoint(%vals --> Str) {
my Int \oldname-field-number = %vals<format>.field-number('oldname');
my Int \newname-field-number = %vals<format>.field-number('newname');
my Str $extra = qq:to/BPF_C_CODE/;
__builtin_memset(\&(ev->oldname), 0, sizeof(ev->oldname) + sizeof(ev->newname));
bpf_probe_read_user_str(ev->oldname, sizeof(ev->oldname), (void*)ctx->args[{oldname-field-number}]);
bpf_probe_read_user_str(ev->newname, sizeof(ev->newname), (void*)ctx->args[{newname-field-number}]);
BPF_C_CODE
self.template: %vals.append( ( event-struct => 'name_event', :$extra ).hash );
}
}
class OpenTracepoint does TracepointTemplate {
method generate-bpf-c-tracepoint(%vals --> Str) {
my Int \field-number = %vals<format>.field-number('filename');
my Str $extra = qq:to/BPF_C_CODE/;
__builtin_memset(\&(ev->filename), 0, sizeof(ev->filename) + sizeof(ev->comm));
bpf_probe_read_user_str(ev->filename, sizeof(ev->filename), (void *)ctx->args[{field-number}]);
bpf_get_current_comm(\&ev->comm, sizeof(ev->comm));
BPF_C_CODE
self.template: %vals.append( ( event-struct => 'open_event', :$extra ).hash );
}
}
class PathnameTracepoint does TracepointTemplate {
method generate-bpf-c-tracepoint(%vals --> Str) {
my Int \field-number = %vals<format>.field-number('pathname');
my Str $extra = qq:to/BPF_C_CODE/;
__builtin_memset(\&(ev->pathname), 0, sizeof(ev->pathname));
bpf_probe_read_user_str(ev->pathname, sizeof(ev->pathname), (void*)ctx->args[{field-number}]);
BPF_C_CODE
self.template: %vals.append( ( event-struct => 'path_event', :$extra ).hash );
}
}
class RetTracepoint does TracepointTemplate {
method generate-bpf-c-tracepoint(%vals --> Str) {
my Str $extra = q:to/BPF_C_CODE/;
ev->ret = ctx->ret;
BPF_C_CODE
self.template: %vals.append( ( event-struct => 'ret_event', :$extra ).hash );
}
}
class NullTracepoint does TracepointTemplate {
method generate-bpf-c-tracepoint(%vals --> Str) {
self.template: %vals.append( ( event-struct => 'null_event' ).hash );
}
}
class Format {
has Field @!internal-fields; # Fields not accessible from raw tracepoints.
has Field @!external-fields; # Fields accessible from raw tracepoints.
has Bool $!is-external = False; # Track internal/external field sections.
has Str $.name is rw;
has Int $.id is rw;
has $.format-impl;
method push(Field \field) {
$!is-external = True if field.name eq '__syscall_nr';
if $!is-external {
push @!external-fields: field;
} else {
push @!internal-fields: field;
return;
}
self.set-format-impl(field.name, field.type);
}
multi method set-format-impl('fd', 'unsigned int') { $!format-impl = FdTracepoint.new }
multi method set-format-impl('newname', 'const char *') { $!format-impl = NameTracepoint.new }
multi method set-format-impl('filename', 'const char *') { $!format-impl = OpenTracepoint.new }
multi method set-format-impl('pathname', 'const char *') { $!format-impl = PathnameTracepoint.new }
multi method set-format-impl('ret', 'long') { $!format-impl = RetTracepoint.new }
multi method set-format-impl($, $) { }
method generate-c-constant returns Str { "#define {$!name.uc} {$!id}" }
method generate-bpf-c-tracepoint returns Str { $!format-impl.generate-bpf-c-tracepoint: (format => self, :$!name).hash }
method field-number(Str \field-name) { @!external-fields.first(*.name eq field-name, :k) - 1 }
method can-generate returns Bool { so $!format-impl.^can('generate-bpf-c-tracepoint') }
method enter-reject returns Bool { $!format-impl !~~ any(FdTracepoint, NameTracepoint, OpenTracepoint, PathnameTracepoint) }
}
class SysTraceFormatActions {
has Hash %!formats;
has Format $!current-format = Format.new;
has Field $!current-field = Field.new;
method TOP($/) { make %!formats }
method whole-format-section($/) {
my ($, \enter-exit, \what) = $!current-format.name.split('_', 3);
%!formats{what}{enter-exit} = $!current-format;
$!current-format = Format.new;
}
method name($/) { $!current-format.name = ~$/<identifier> }
method id($/) { $!current-format.id = +$/<number> }
method field-declaration($/) {
$!current-field.name = ~$/<identifier>;
$!current-field.type = $/<field-type>.join('').trim-trailing;
$!current-format.push($!current-field);
$!current-field = Field.new;
}
method field-offset($/) { $!current-field.offset = +$/<number> }
method field-size($/) { $!current-field.size = +$/<number> }
method field-signed($/) { $!current-field.signed = +$/<cbool> == 0 ?? False !! True }
}
say qq:to/BPF_C_CODE/;
// Code generated - don't change manually!
BPF_C_CODE
my Format @formats = gather for
SysTraceFormat.parse($*IN.slurp, actions => SysTraceFormatActions.new).made.values -> %syscall {
if !all(%syscall.values.map(*.can-generate)) {
say "// Ignoring {%syscall.values.map(*.name).sort} as possibly not file I/O related";
next;
} elsif %syscall<enter>.enter-reject {
say "// Ignoring {%syscall.values.map(*.name).sort} as enter-rejected";
next;
}
.take for %syscall.values;
}
@formats .= sort({ $^b.id cmp $^a.id });
say qq:to/BPF_C_CODE/;
{@formats.map(*.generate-c-constant).join("\n")}
{@formats.map(*.generate-bpf-c-tracepoint).join("\n")}
BPF_C_CODE
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