tiny.sys.process.tracing.operations

1const std = @import("std");2const builtin = @import("builtin");3const linux = std.os.linux;4const ptrace = linux.PTRACE;56pub const Event = enum { fork, vfork, clone, exec, stop, signal, syscall };7pub const Observation = struct {8    pid: i32,9    state: union(enum) {10        ended: struct { code: ?u8, signal: ?u8 },11        stopped: struct { event: Event, signal: u8 },12    },13};1415pub fn attach(pid: i32, syscalls: bool) !void {16    if (comptime builtin.os.tag != .linux) return error.UnsupportedPlatform;17    const options = ptrace.O.TRACEFORK | ptrace.O.TRACEVFORK | ptrace.O.TRACECLONE |18        ptrace.O.TRACEEXEC | ptrace.O.EXITKILL |19        (if (syscalls) ptrace.O.TRACESYSGOOD else @as(u32, 0));20    try operation(ptrace.SEIZE, pid, options);21}2223pub fn continueTask(pid: i32, signal: u8, syscalls: bool) !void {24    try operation(if (syscalls) ptrace.SYSCALL else ptrace.CONT, pid, signal);25}26pub fn listen(pid: i32) !void {27    try operation(ptrace.LISTEN, pid, 0);28}29pub fn terminate(pid: i32) void {30    _ = linux.kill(pid, .KILL);31}3233pub fn message(pid: i32) !usize {34    var result: usize = 0;35    try operation(ptrace.GETEVENTMSG, pid, @intFromPtr(&result));36    return result;37}3839pub fn wait() !Observation {40    var status: i32 = 0;41    const result = linux.waitpid(-1, &status, 0x40000000);42    switch (linux.errno(result)) {43        .SUCCESS => {},44        .INTR => return error.Interrupted,45        .CHILD => return error.NoChildren,46        else => return error.TraceWaitFailed,47    }48    const pid: i32 = @intCast(result);49    if ((status & 0xff) != 0x7f) {50        const signal: ?u8 = if ((status & 0x7f) == 0) null else @intCast(status & 0x7f);51        const code: ?u8 = if (signal == null) @intCast((status >> 8) & 0xff) else null;52        return .{ .pid = pid, .state = .{ .ended = .{ .code = code, .signal = signal } } };53    }54    const event: Event = switch (status >> 16) {55        ptrace.EVENT.FORK => .fork,56        ptrace.EVENT.VFORK => .vfork,57        ptrace.EVENT.CLONE => .clone,58        ptrace.EVENT.EXEC => .exec,59        ptrace.EVENT.STOP => .stop,60        0 => if (((status >> 8) & 0xff) == 133) .syscall else .signal,61        else => return error.UnexpectedTraceEvent,62    };63    return .{ .pid = pid, .state = .{ .stopped = .{64        .event = event,65        .signal = @intCast((status >> 8) & 0xff),66    } } };67}6869fn operation(request: u32, pid: i32, data: usize) !void {70    std.debug.assert(pid > 0);71    const result = linux.ptrace(request, pid, 0, data, 0);72    return switch (linux.errno(result)) {73        .SUCCESS => {},74        .PERM, .ACCES => error.TracingPermissionDenied,75        else => error.TraceOperationFailed,76    };77}

1pub const operations = @import("operations.zig");