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#!/usr/bin/env raku
use v6.d;
#use Grammar::Debugger;
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;
}
class Format {
# Fields not accessible from raw tracepoints.
has Field @!internal-fields;
# Fields accessible from raw tracepoints.
has Field @!external-fields;
# Track internal/external field sections.
has Bool $!is-external = False;
has Str $.name is rw;
has Int $.id is rw;
# file descriptor passed to syscalls.
has Bool $.has-fd is rw = False;
# Tracepoint has oldname/newname
has Bool $.has-name is rw = False;
# Tracepoint has pathname
has Bool $.has-path is rw = False;
# Syscall returns with a long value (e.g. bytes read/written)
has Bool $.has-long-ret is rw = False;
method push(Field \field) {
# External fields start from this field name.
$!is-external = True if field.name eq '__syscall_nr';
if $!is-external {
push @!external-fields: field;
} else {
push @!internal-fields: field;
return;
}
if (field.name eq 'fd' && field.type eq 'unsigned int') {
$!has-fd = True;
} elsif (field.name eq 'newname' && field.type eq 'const char *') {
$!has-name = True;
} elsif (field.name eq 'pathname' && field.type eq 'const char *') {
$!has-path = True;
} elsif (field.name eq 'ret' && field.type eq 'long') {
$.has-long-ret = True;
}
}
method !field-number(Str \field-name) {
@!external-fields.first(*.name eq field-name, :k) - 1;
}
method generate-constant returns Str {
"#define {$!name.uc} {$!id}";
}
method generate-probe returns Str {
my \is-enter = $!name.split('_')[1] eq 'enter';
my \ctx-struct = is-enter ?? 'trace_event_raw_sys_enter'
!! 'trace_event_raw_sys_exit';
my \event-struct = do if $!has-fd { 'fd_event' }
elsif $!has-long-ret { 'ret_event' }
elsif $!has-name { 'name_event' }
elsif $!has-path { 'path_event' }
else { 'null_event' };
my \extra-data = do if $!has-fd { 'ev->fd = (__s32)ctx->args[0];' }
elsif $!has-long-ret { 'ev->ret = ctx->ret;' }
elsif $!has-name {
my Int \oldname-index = self!field-number('oldname');
my Int \newname-index = self!field-number('newname');
qq:to/END/.trim-trailing;
__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-index}]);
bpf_probe_read_user_str(ev->newname, sizeof(ev->newname), (void*)ctx->args[{newname-index}]);
END
} elsif $!has-path {
my Int \pathname-index = self!field-number('pathname');
qq:to/END/.trim-trailing;
__builtin_memset(\&(ev->pathname), 0, sizeof(ev->pathname));
bpf_probe_read_user_str(ev->pathname, sizeof(ev->pathname), (void*)ctx->args[{pathname-index}]);
END
}
else { '' };
qq:to/END/;
SEC("tracepoint/syscalls/{$!name}")
int handle_{$!name.lc}(struct {ctx-struct} *ctx) \{
__u32 pid, tid;
if (filter(&pid, &tid))
return 0;
struct {event-struct} *ev = bpf_ringbuf_reserve(&event_map, sizeof(struct {event-struct}), 0);
if (!ev)
return 0;
ev->event_type = {(is-enter ?? 'ENTER_' !! 'EXIT_') ~ event-struct.uc};
ev->trace_id = {$!name.uc};
ev->pid = pid;
ev->tid = tid;
ev->time = bpf_ktime_get_ns() / 1000;
{extra-data}
bpf_ringbuf_submit(ev, 0);
return 0;
\}
END
}
}
class SysTraceFormatActions {
has Format @!formats;
has Format $!current-format = Format.new;
has Field $!current-field = Field.new;
method TOP($/) { make @!formats }
method whole-format-section($/) {
push @!formats: $!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 }
}
my Format @formats = gather for SysTraceFormat
.parse($*IN.slurp,:actions(SysTraceFormatActions.new)).made
# For each enter there is an exit tracepoint. E.g. sys_enter_open and sys_exit_open
.classify(*.name.split('_').tail).values
.grep({ $_.grep(*.has-fd) || $_.grep(*.has-name) || $_.grep(*.has-path) }) -> @_ { .take for @_ }
@formats .= sort(*.id);
say qq:to/END/;
// Code generated - don't change manually!
{@formats.map(*.generate-constant).join("\n")}
{@formats.map(*.generate-probe).join("\n")}
END
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