Merge #568

568: Add process_vm_readv and process_vm_writev r=asomers a=geofft

1 files changed, 79 insertions, 0 deletions

diff --git a/src/sys/uio.rs b/src/sys/uio.rs
index edca8cb4..16426ab9 100644
--- a/src/sys/uio.rs
+++ b/src/sys/uio.rs
@@ -56,6 +56,85 @@ pub fn pread(fd: RawFd, buf: &mut [u8], offset: off_t) -> Result<usize>{
     Errno::result(res).map(|r| r as usize)
 }
 
+/// A slice of memory in a remote process, starting at address `base`
+/// and consisting of `len` bytes.
+///
+/// This is the same underlying C structure as [`IoVec`](struct.IoVec.html),
+/// except that it refers to memory in some other process, and is
+/// therefore not represented in Rust by an actual slice as IoVec is. It
+/// is used with [`process_vm_readv`](fn.process_vm_readv.html)
+/// and [`process_vm_writev`](fn.process_vm_writev.html).
+#[cfg(target_os = "linux")]
+#[repr(C)]
+pub struct RemoteIoVec {
+    /// The starting address of this slice (`iov_base`).
+    pub base: usize,
+    /// The number of bytes in this slice (`iov_len`).
+    pub len: usize,
+}
+
+/// Write data directly to another process's virtual memory
+/// (see [`process_vm_writev`(2)]).
+///
+/// `local_iov` is a list of [`IoVec`]s containing the data to be written,
+/// and `remote_iov` is a list of [`RemoteIoVec`]s identifying where the
+/// data should be written in the target process. On success, returns the
+/// number of bytes written, which will always be a whole
+/// number of remote_iov chunks.
+///
+/// This requires the same permissions as debugging the process using
+/// [ptrace]: you must either be a privileged process (with
+/// `CAP_SYS_PTRACE`), or you must be running as the same user as the
+/// target process and the OS must have unprivileged debugging enabled.
+///
+/// This function is only available on Linux.
+///
+/// [`process_vm_writev`(2)]: http://man7.org/linux/man-pages/man2/process_vm_writev.2.html
+/// [ptrace]: ../ptrace/index.html
+/// [`IoVec`]: struct.IoVec.html
+/// [`RemoteIoVec`]: struct.RemoteIoVec.html
+#[cfg(target_os = "linux")]
+pub fn process_vm_writev(pid: ::unistd::Pid, local_iov: &[IoVec<&[u8]>], remote_iov: &[RemoteIoVec]) -> Result<usize> {
+    let res = unsafe {
+        libc::process_vm_writev(pid.into(),
+                                local_iov.as_ptr() as *const libc::iovec, local_iov.len() as libc::c_ulong,
+                                remote_iov.as_ptr() as *const libc::iovec, remote_iov.len() as libc::c_ulong, 0)
+    };
+
+    Errno::result(res).map(|r| r as usize)
+}
+
+/// Read data directly from another process's virtual memory
+/// (see [`process_vm_readv`(2)]).
+///
+/// `local_iov` is a list of [`IoVec`]s containing the buffer to copy
+/// data into, and `remote_iov` is a list of [`RemoteIoVec`]s identifying
+/// where the source data is in the target process. On success,
+/// returns the number of bytes written, which will always be a whole
+/// number of remote_iov chunks.
+///
+/// This requires the same permissions as debugging the process using
+/// [ptrace]: you must either be a privileged process (with
+/// `CAP_SYS_PTRACE`), or you must be running as the same user as the
+/// target process and the OS must have unprivileged debugging enabled.
+///
+/// This function is only available on Linux.
+///
+/// [`process_vm_readv`(2)]: http://man7.org/linux/man-pages/man2/process_vm_readv.2.html
+/// [ptrace]: ../ptrace/index.html
+/// [`IoVec`]: struct.IoVec.html
+/// [`RemoteIoVec`]: struct.RemoteIoVec.html
+#[cfg(any(target_os = "linux"))]
+pub fn process_vm_readv(pid: ::unistd::Pid, local_iov: &[IoVec<&mut [u8]>], remote_iov: &[RemoteIoVec]) -> Result<usize> {
+    let res = unsafe {
+        libc::process_vm_readv(pid.into(),
+                               local_iov.as_ptr() as *const libc::iovec, local_iov.len() as libc::c_ulong,
+                               remote_iov.as_ptr() as *const libc::iovec, remote_iov.len() as libc::c_ulong, 0)
+    };
+
+    Errno::result(res).map(|r| r as usize)
+}
+
 #[repr(C)]
 pub struct IoVec<T>(libc::iovec, PhantomData<T>);