1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
use errno::Errno;
use libc::{self, c_int};
use std::ptr;
use sys::signal::Signal;
use unistd::Pid;
use Result;

pub type RequestType = c_int;

cfg_if! {
    if #[cfg(any(target_os = "dragonfly", 
                 target_os = "freebsd", 
                 target_os = "macos",
                 target_os = "openbsd"))] {
        #[doc(hidden)]
        pub type AddressType = *mut ::libc::c_char;
    } else {
        #[doc(hidden)]
        pub type AddressType = *mut ::libc::c_void;
    }
}

libc_enum! {
    #[repr(i32)]
    /// Ptrace Request enum defining the action to be taken.
    pub enum Request {
        PT_TRACE_ME,
        PT_READ_I,
        PT_READ_D,
        #[cfg(target_os = "macos")]
        PT_READ_U,
        PT_WRITE_I,
        PT_WRITE_D,
        #[cfg(target_os = "macos")]
        PT_WRITE_U,
        PT_CONTINUE,
        PT_KILL,
        #[cfg(any(any(target_os = "dragonfly",
                  target_os = "freebsd",
                  target_os = "macos"),
                  all(target_os = "openbsd", target_arch = "x86_64"),
                  all(target_os = "netbsd", any(target_arch = "x86_64",
                                                target_arch = "powerpc"))))]
        PT_STEP,
        PT_ATTACH,
        PT_DETACH,
        #[cfg(target_os = "macos")]
        PT_SIGEXC,
        #[cfg(target_os = "macos")]
        PT_THUPDATE,
        #[cfg(target_os = "macos")]
        PT_ATTACHEXC
    }
}

unsafe fn ptrace_other(
    request: Request,
    pid: Pid,
    addr: AddressType,
    data: c_int,
) -> Result<c_int> {
    Errno::result(libc::ptrace(
        request as RequestType,
        libc::pid_t::from(pid),
        addr,
        data,
    )).map(|_| 0)
}

/// Sets the process as traceable, as with `ptrace(PT_TRACEME, ...)`
///
/// Indicates that this process is to be traced by its parent.
/// This is the only ptrace request to be issued by the tracee.
pub fn traceme() -> Result<()> {
    unsafe { ptrace_other(Request::PT_TRACE_ME, Pid::from_raw(0), ptr::null_mut(), 0).map(drop) }
}

/// Attach to a running process, as with `ptrace(PT_ATTACH, ...)`
///
/// Attaches to the process specified by `pid`, making it a tracee of the calling process.
pub fn attach(pid: Pid) -> Result<()> {
    unsafe { ptrace_other(Request::PT_ATTACH, pid, ptr::null_mut(), 0).map(drop) }
}

/// Detaches the current running process, as with `ptrace(PT_DETACH, ...)`
///
/// Detaches from the process specified by `pid` allowing it to run freely, optionally delivering a
/// signal specified by `sig`.
pub fn detach<T: Into<Option<Signal>>>(pid: Pid, sig: T) -> Result<()> {
    let data = match sig.into() {
        Some(s) => s as c_int,
        None => 0,
    };
    unsafe {
        ptrace_other(Request::PT_DETACH, pid, ptr::null_mut(), data).map(drop)
    }
}

/// Restart the stopped tracee process, as with `ptrace(PTRACE_CONT, ...)`
///
/// Continues the execution of the process with PID `pid`, optionally
/// delivering a signal specified by `sig`.
pub fn cont<T: Into<Option<Signal>>>(pid: Pid, sig: T) -> Result<()> {
    let data = match sig.into() {
        Some(s) => s as c_int,
        None => 0,
    };
    unsafe {
        // Ignore the useless return value
        ptrace_other(Request::PT_CONTINUE, pid, 1 as AddressType, data).map(drop)
    }
}

/// Issues a kill request as with `ptrace(PT_KILL, ...)`
///
/// This request is equivalent to `ptrace(PT_CONTINUE, ..., SIGKILL);` 
pub fn kill(pid: Pid) -> Result<()> {
    unsafe {
        ptrace_other(Request::PT_KILL, pid, 0 as AddressType, 0).map(drop)
    }
}

/// Move the stopped tracee process forward by a single step as with
/// `ptrace(PT_STEP, ...)`
///
/// Advances the execution of the process with PID `pid` by a single step optionally delivering a
/// signal specified by `sig`.
///
/// # Example
/// ```rust
/// extern crate nix;
/// use nix::sys::ptrace::step;
/// use nix::unistd::Pid;
/// use nix::sys::signal::Signal;
/// use nix::sys::wait::*;
/// fn main() {
///     // If a process changes state to the stopped state because of a SIGUSR1
///     // signal, this will step the process forward and forward the user
///     // signal to the stopped process
///     match waitpid(Pid::from_raw(-1), None) {
///         Ok(WaitStatus::Stopped(pid, Signal::SIGUSR1)) => {
///             let _ = step(pid, Signal::SIGUSR1);
///         }
///         _ => {},
///     }
/// }
/// ```
#[cfg(
    any(
        any(target_os = "dragonfly", target_os = "freebsd", target_os = "macos"),
        all(target_os = "openbsd", target_arch = "x86_64"),
        all(target_os = "netbsd",
            any(target_arch = "x86_64", target_arch = "powerpc")
        )
    )
)]
pub fn step<T: Into<Option<Signal>>>(pid: Pid, sig: T) -> Result<()> {
    let data = match sig.into() {
        Some(s) => s as c_int,
        None => 0,
    };
    unsafe { ptrace_other(Request::PT_STEP, pid, ptr::null_mut(), data).map(drop) }
}

/// Reads a word from a processes memory at the given address
pub fn read(pid: Pid, addr: AddressType) -> Result<c_int> {
    unsafe {
        // Traditionally there was a difference between reading data or
        // instruction memory but not in modern systems.
        ptrace_other(Request::PT_READ_D, pid, addr, 0)
    }
}

/// Writes a word into the processes memory at the given address
pub fn write(pid: Pid, addr: AddressType, data: c_int) -> Result<()> {
    unsafe { ptrace_other(Request::PT_WRITE_D, pid, addr, data).map(drop) }
}